ASR_BASE
Change-Id: Icf3719cc0afe3eeb3edc7fa80a2eb5199ca9dda1
diff --git a/marvell/linux/net/core/skbuff.c b/marvell/linux/net/core/skbuff.c
new file mode 100644
index 0000000..1031495
--- /dev/null
+++ b/marvell/linux/net/core/skbuff.c
@@ -0,0 +1,6468 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Routines having to do with the 'struct sk_buff' memory handlers.
+ *
+ * Authors: Alan Cox <alan@lxorguk.ukuu.org.uk>
+ * Florian La Roche <rzsfl@rz.uni-sb.de>
+ *
+ * Fixes:
+ * Alan Cox : Fixed the worst of the load
+ * balancer bugs.
+ * Dave Platt : Interrupt stacking fix.
+ * Richard Kooijman : Timestamp fixes.
+ * Alan Cox : Changed buffer format.
+ * Alan Cox : destructor hook for AF_UNIX etc.
+ * Linus Torvalds : Better skb_clone.
+ * Alan Cox : Added skb_copy.
+ * Alan Cox : Added all the changed routines Linus
+ * only put in the headers
+ * Ray VanTassle : Fixed --skb->lock in free
+ * Alan Cox : skb_copy copy arp field
+ * Andi Kleen : slabified it.
+ * Robert Olsson : Removed skb_head_pool
+ *
+ * NOTE:
+ * The __skb_ routines should be called with interrupts
+ * disabled, or you better be *real* sure that the operation is atomic
+ * with respect to whatever list is being frobbed (e.g. via lock_sock()
+ * or via disabling bottom half handlers, etc).
+ */
+
+/*
+ * The functions in this file will not compile correctly with gcc 2.4.x
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/module.h>
+#include <linux/types.h>
+#include <linux/kernel.h>
+#include <linux/mm.h>
+#include <linux/interrupt.h>
+#include <linux/in.h>
+#include <linux/inet.h>
+#include <linux/slab.h>
+#include <linux/tcp.h>
+#include <linux/udp.h>
+#include <linux/sctp.h>
+#include <linux/netdevice.h>
+#ifdef CONFIG_NET_CLS_ACT
+#include <net/pkt_sched.h>
+#endif
+#include <linux/string.h>
+#include <linux/skbuff.h>
+#include <linux/splice.h>
+#include <linux/cache.h>
+#include <linux/rtnetlink.h>
+#include <linux/init.h>
+#include <linux/scatterlist.h>
+#include <linux/errqueue.h>
+#include <linux/prefetch.h>
+#include <linux/if_vlan.h>
+#include <linux/mpls.h>
+#include <linux/if.h>
+
+#include <net/protocol.h>
+#include <net/dst.h>
+#include <net/sock.h>
+#include <net/checksum.h>
+#include <net/ip6_checksum.h>
+#include <net/xfrm.h>
+#include <net/mpls.h>
+
+#include <linux/uaccess.h>
+#include <trace/events/skb.h>
+#include <linux/highmem.h>
+#include <linux/capability.h>
+#include <linux/user_namespace.h>
+#include <linux/indirect_call_wrapper.h>
+#include <trace/hooks/net.h>
+#ifdef CONFIG_ASR_BM
+#include <linux/asrbm.h>
+#endif
+#include <linux/icmp.h>
+#include "datagram.h"
+#include "sock_destructor.h"
+
+struct kmem_cache *skbuff_head_cache __ro_after_init;
+static struct kmem_cache *skbuff_fclone_cache __ro_after_init;
+#ifdef CONFIG_SKB_EXTENSIONS
+static struct kmem_cache *skbuff_ext_cache __ro_after_init;
+#endif
+int sysctl_max_skb_frags __read_mostly = MAX_SKB_FRAGS;
+EXPORT_SYMBOL(sysctl_max_skb_frags);
+
+static void skb_p_revert(struct sk_buff *skb);
+
+/**
+ * skb_panic - private function for out-of-line support
+ * @skb: buffer
+ * @sz: size
+ * @addr: address
+ * @msg: skb_over_panic or skb_under_panic
+ *
+ * Out-of-line support for skb_put() and skb_push().
+ * Called via the wrapper skb_over_panic() or skb_under_panic().
+ * Keep out of line to prevent kernel bloat.
+ * __builtin_return_address is not used because it is not always reliable.
+ */
+static void skb_panic(struct sk_buff *skb, unsigned int sz, void *addr,
+ const char msg[])
+{
+ pr_emerg("%s: text:%p len:%d put:%d head:%p data:%p tail:%#lx end:%#lx dev:%s\n",
+ msg, addr, skb->len, sz, skb->head, skb->data,
+ (unsigned long)skb->tail, (unsigned long)skb->end,
+ skb->dev ? skb->dev->name : "<NULL>");
+ BUG();
+}
+
+static void skb_over_panic(struct sk_buff *skb, unsigned int sz, void *addr)
+{
+ skb_panic(skb, sz, addr, __func__);
+}
+
+static void skb_under_panic(struct sk_buff *skb, unsigned int sz, void *addr)
+{
+ skb_panic(skb, sz, addr, __func__);
+}
+
+void netdev_pkt_dump(struct iphdr *iph, const char *func)
+{
+ struct icmphdr *icmph;
+
+ if (iph->protocol == IPPROTO_ICMP) {
+ icmph = (struct icmphdr *)((u8 *)iph + (iph->ihl << 2));
+ if (icmph->type == ICMP_ECHO)
+ printk(KERN_DEBUG "%s: ICMP request: From %pI4 to %pI4, "
+ "code=%d sequence=%d\n",
+ func, &iph->saddr, &iph->daddr, icmph->code,
+ be16_to_cpu(icmph->un.echo.sequence));
+ else if (icmph->type == ICMP_ECHOREPLY)
+ printk(KERN_DEBUG "%s: ICMP reply: From %pI4 to %pI4 "
+ "code=%d sequence=%d\n",
+ func, &iph->saddr, &iph->daddr, icmph->code,
+ be16_to_cpu(icmph->un.echo.sequence));
+ } else if (iph->protocol == IPPROTO_TCP) {
+ struct tcphdr *th = (struct tcphdr *)(iph + 1);
+
+ printk(KERN_DEBUG "%s: TCP: From%pI4:%u to dst=%pI4:%u "
+ "ID=%u seq=%u ack=%u\r\n",
+ func, &iph->saddr, ntohs(th->source),
+ &iph->daddr, ntohs(th->dest),
+ ntohs(iph->id), ntohl(th->seq), ntohl(th->ack_seq));
+ }
+}
+
+/*
+ * kmalloc_reserve is a wrapper around kmalloc_node_track_caller that tells
+ * the caller if emergency pfmemalloc reserves are being used. If it is and
+ * the socket is later found to be SOCK_MEMALLOC then PFMEMALLOC reserves
+ * may be used. Otherwise, the packet data may be discarded until enough
+ * memory is free
+ */
+#define kmalloc_reserve(size, gfp, node, pfmemalloc) \
+ __kmalloc_reserve(size, gfp, node, _RET_IP_, pfmemalloc)
+
+static void *__kmalloc_reserve(size_t size, gfp_t flags, int node,
+ unsigned long ip, bool *pfmemalloc)
+{
+ void *obj;
+ bool ret_pfmemalloc = false;
+
+ /*
+ * Try a regular allocation, when that fails and we're not entitled
+ * to the reserves, fail.
+ */
+ obj = kmalloc_node_track_caller(size,
+ flags | __GFP_NOMEMALLOC | __GFP_NOWARN,
+ node);
+ if (obj || !(gfp_pfmemalloc_allowed(flags)))
+ goto out;
+
+ /* Try again but now we are using pfmemalloc reserves */
+ ret_pfmemalloc = true;
+ obj = kmalloc_node_track_caller(size, flags, node);
+
+out:
+ if (pfmemalloc)
+ *pfmemalloc = ret_pfmemalloc;
+
+ return obj;
+}
+
+/* Allocate a new skbuff. We do this ourselves so we can fill in a few
+ * 'private' fields and also do memory statistics to find all the
+ * [BEEP] leaks.
+ *
+ */
+
+/**
+ * __alloc_skb - allocate a network buffer
+ * @size: size to allocate
+ * @gfp_mask: allocation mask
+ * @flags: If SKB_ALLOC_FCLONE is set, allocate from fclone cache
+ * instead of head cache and allocate a cloned (child) skb.
+ * If SKB_ALLOC_RX is set, __GFP_MEMALLOC will be used for
+ * allocations in case the data is required for writeback
+ * @node: numa node to allocate memory on
+ *
+ * Allocate a new &sk_buff. The returned buffer has no headroom and a
+ * tail room of at least size bytes. The object has a reference count
+ * of one. The return is the buffer. On a failure the return is %NULL.
+ *
+ * Buffers may only be allocated from interrupts using a @gfp_mask of
+ * %GFP_ATOMIC.
+ */
+struct sk_buff *__alloc_skb(unsigned int size, gfp_t gfp_mask,
+ int flags, int node)
+{
+ struct kmem_cache *cache;
+ struct skb_shared_info *shinfo;
+ struct sk_buff *skb;
+ u8 *data;
+ bool pfmemalloc;
+
+ cache = (flags & SKB_ALLOC_FCLONE)
+ ? skbuff_fclone_cache : skbuff_head_cache;
+
+ if (sk_memalloc_socks() && (flags & SKB_ALLOC_RX))
+ gfp_mask |= __GFP_MEMALLOC;
+
+ /* Get the HEAD */
+ skb = kmem_cache_alloc_node(cache, gfp_mask & ~__GFP_DMA, node);
+ if (!skb)
+ goto out;
+ prefetchw(skb);
+
+ /* We do our best to align skb_shared_info on a separate cache
+ * line. It usually works because kmalloc(X > SMP_CACHE_BYTES) gives
+ * aligned memory blocks, unless SLUB/SLAB debug is enabled.
+ * Both skb->head and skb_shared_info are cache line aligned.
+ */
+ size = SKB_DATA_ALIGN(size);
+ size += SKB_DATA_ALIGN(sizeof(struct skb_shared_info));
+ data = kmalloc_reserve(size, gfp_mask, node, &pfmemalloc);
+ if (!data)
+ goto nodata;
+ /* kmalloc(size) might give us more room than requested.
+ * Put skb_shared_info exactly at the end of allocated zone,
+ * to allow max possible filling before reallocation.
+ */
+ size = SKB_WITH_OVERHEAD(ksize(data));
+ prefetchw(data + size);
+
+ /*
+ * Only clear those fields we need to clear, not those that we will
+ * actually initialise below. Hence, don't put any more fields after
+ * the tail pointer in struct sk_buff!
+ */
+ memset(skb, 0, offsetof(struct sk_buff, tail));
+ /* Account for allocated memory : skb + skb->head */
+ skb->truesize = SKB_TRUESIZE(size);
+ skb->pfmemalloc = pfmemalloc;
+ refcount_set(&skb->users, 1);
+ skb->head = data;
+ skb->data = data;
+ skb_reset_tail_pointer(skb);
+ skb->end = skb->tail + size;
+ skb->mac_header = (typeof(skb->mac_header))~0U;
+ skb->transport_header = (typeof(skb->transport_header))~0U;
+
+ /* make sure we initialize shinfo sequentially */
+ shinfo = skb_shinfo(skb);
+ memset(shinfo, 0, offsetof(struct skb_shared_info, dataref));
+ atomic_set(&shinfo->dataref, 1);
+
+ if (flags & SKB_ALLOC_FCLONE) {
+ struct sk_buff_fclones *fclones;
+
+ fclones = container_of(skb, struct sk_buff_fclones, skb1);
+
+ skb->fclone = SKB_FCLONE_ORIG;
+ refcount_set(&fclones->fclone_ref, 1);
+
+ fclones->skb2.fclone = SKB_FCLONE_CLONE;
+ }
+out:
+ return skb;
+nodata:
+ kmem_cache_free(cache, skb);
+ skb = NULL;
+ goto out;
+}
+EXPORT_SYMBOL(__alloc_skb);
+
+/* Caller must provide SKB that is memset cleared */
+static struct sk_buff *__build_skb_around(struct sk_buff *skb,
+ void *data, unsigned int frag_size)
+{
+ struct skb_shared_info *shinfo;
+ unsigned int size = frag_size ? : ksize(data);
+
+ size -= SKB_DATA_ALIGN(sizeof(struct skb_shared_info));
+
+ /* Assumes caller memset cleared SKB */
+ skb->truesize = SKB_TRUESIZE(size);
+ refcount_set(&skb->users, 1);
+ skb->head = data;
+ skb->data = data;
+ skb_reset_tail_pointer(skb);
+ skb->end = skb->tail + size;
+ skb->mac_header = (typeof(skb->mac_header))~0U;
+ skb->transport_header = (typeof(skb->transport_header))~0U;
+
+ /* make sure we initialize shinfo sequentially */
+ shinfo = skb_shinfo(skb);
+ memset(shinfo, 0, offsetof(struct skb_shared_info, dataref));
+ atomic_set(&shinfo->dataref, 1);
+
+ return skb;
+}
+
+/**
+ * __build_skb - build a network buffer
+ * @data: data buffer provided by caller
+ * @frag_size: size of data, or 0 if head was kmalloced
+ *
+ * Allocate a new &sk_buff. Caller provides space holding head and
+ * skb_shared_info. @data must have been allocated by kmalloc() only if
+ * @frag_size is 0, otherwise data should come from the page allocator
+ * or vmalloc()
+ * The return is the new skb buffer.
+ * On a failure the return is %NULL, and @data is not freed.
+ * Notes :
+ * Before IO, driver allocates only data buffer where NIC put incoming frame
+ * Driver should add room at head (NET_SKB_PAD) and
+ * MUST add room at tail (SKB_DATA_ALIGN(skb_shared_info))
+ * After IO, driver calls build_skb(), to allocate sk_buff and populate it
+ * before giving packet to stack.
+ * RX rings only contains data buffers, not full skbs.
+ */
+struct sk_buff *__build_skb(void *data, unsigned int frag_size)
+{
+ struct sk_buff *skb;
+
+ skb = kmem_cache_alloc(skbuff_head_cache, GFP_ATOMIC);
+ if (unlikely(!skb))
+ return NULL;
+
+ memset(skb, 0, offsetof(struct sk_buff, tail));
+
+ return __build_skb_around(skb, data, frag_size);
+}
+
+/* build_skb() is wrapper over __build_skb(), that specifically
+ * takes care of skb->head and skb->pfmemalloc
+ * This means that if @frag_size is not zero, then @data must be backed
+ * by a page fragment, not kmalloc() or vmalloc()
+ */
+struct sk_buff *build_skb(void *data, unsigned int frag_size)
+{
+ struct sk_buff *skb = __build_skb(data, frag_size);
+
+ if (skb && frag_size) {
+ skb->head_frag = 1;
+ if (page_is_pfmemalloc(virt_to_head_page(data)))
+ skb->pfmemalloc = 1;
+ }
+ return skb;
+}
+EXPORT_SYMBOL(build_skb);
+
+/**
+ * build_skb_around - build a network buffer around provided skb
+ * @skb: sk_buff provide by caller, must be memset cleared
+ * @data: data buffer provided by caller
+ * @frag_size: size of data, or 0 if head was kmalloced
+ */
+struct sk_buff *build_skb_around(struct sk_buff *skb,
+ void *data, unsigned int frag_size)
+{
+ if (unlikely(!skb))
+ return NULL;
+
+ skb = __build_skb_around(skb, data, frag_size);
+
+ if (skb && frag_size) {
+ skb->head_frag = 1;
+ if (page_is_pfmemalloc(virt_to_head_page(data)))
+ skb->pfmemalloc = 1;
+ }
+ return skb;
+}
+EXPORT_SYMBOL(build_skb_around);
+
+#define NAPI_SKB_CACHE_SIZE 64
+
+struct napi_alloc_cache {
+ struct page_frag_cache page;
+ unsigned int skb_count;
+ void *skb_cache[NAPI_SKB_CACHE_SIZE];
+};
+
+static DEFINE_PER_CPU(struct page_frag_cache, netdev_alloc_cache);
+static DEFINE_PER_CPU(struct napi_alloc_cache, napi_alloc_cache);
+
+static void *__napi_alloc_frag(unsigned int fragsz, gfp_t gfp_mask)
+{
+ struct napi_alloc_cache *nc = this_cpu_ptr(&napi_alloc_cache);
+
+ return page_frag_alloc(&nc->page, fragsz, gfp_mask);
+}
+
+void *napi_alloc_frag(unsigned int fragsz)
+{
+ fragsz = SKB_DATA_ALIGN(fragsz);
+
+ return __napi_alloc_frag(fragsz, GFP_ATOMIC);
+}
+EXPORT_SYMBOL(napi_alloc_frag);
+
+/**
+ * netdev_alloc_frag - allocate a page fragment
+ * @fragsz: fragment size
+ *
+ * Allocates a frag from a page for receive buffer.
+ * Uses GFP_ATOMIC allocations.
+ */
+void *netdev_alloc_frag(unsigned int fragsz)
+{
+ struct page_frag_cache *nc;
+ void *data;
+
+ fragsz = SKB_DATA_ALIGN(fragsz);
+ if (in_irq() || irqs_disabled()) {
+ nc = this_cpu_ptr(&netdev_alloc_cache);
+ data = page_frag_alloc(nc, fragsz, GFP_ATOMIC);
+ } else {
+ local_bh_disable();
+ data = __napi_alloc_frag(fragsz, GFP_ATOMIC);
+ local_bh_enable();
+ }
+ return data;
+}
+EXPORT_SYMBOL(netdev_alloc_frag);
+
+/**
+ * __netdev_alloc_skb - allocate an skbuff for rx on a specific device
+ * @dev: network device to receive on
+ * @len: length to allocate
+ * @gfp_mask: get_free_pages mask, passed to alloc_skb
+ *
+ * Allocate a new &sk_buff and assign it a usage count of one. The
+ * buffer has NET_SKB_PAD headroom built in. Users should allocate
+ * the headroom they think they need without accounting for the
+ * built in space. The built in space is used for optimisations.
+ *
+ * %NULL is returned if there is no free memory.
+ */
+struct sk_buff *__netdev_alloc_skb(struct net_device *dev, unsigned int len,
+ gfp_t gfp_mask)
+{
+ struct page_frag_cache *nc;
+ struct sk_buff *skb;
+ bool pfmemalloc;
+ void *data;
+
+ len += NET_SKB_PAD;
+
+ /* If requested length is either too small or too big,
+ * we use kmalloc() for skb->head allocation.
+ */
+ if (len <= SKB_WITH_OVERHEAD(1024) ||
+ len > SKB_WITH_OVERHEAD(PAGE_SIZE) ||
+ (gfp_mask & (__GFP_DIRECT_RECLAIM | GFP_DMA))) {
+ skb = __alloc_skb(len, gfp_mask, SKB_ALLOC_RX, NUMA_NO_NODE);
+ if (!skb)
+ goto skb_fail;
+ goto skb_success;
+ }
+
+ len += SKB_DATA_ALIGN(sizeof(struct skb_shared_info));
+ len = SKB_DATA_ALIGN(len);
+
+ if (sk_memalloc_socks())
+ gfp_mask |= __GFP_MEMALLOC;
+
+ if (in_irq() || irqs_disabled()) {
+ nc = this_cpu_ptr(&netdev_alloc_cache);
+ data = page_frag_alloc(nc, len, gfp_mask);
+ pfmemalloc = nc->pfmemalloc;
+ } else {
+ local_bh_disable();
+ nc = this_cpu_ptr(&napi_alloc_cache.page);
+ data = page_frag_alloc(nc, len, gfp_mask);
+ pfmemalloc = nc->pfmemalloc;
+ local_bh_enable();
+ }
+
+ if (unlikely(!data))
+ return NULL;
+
+ skb = __build_skb(data, len);
+ if (unlikely(!skb)) {
+ skb_free_frag(data);
+ return NULL;
+ }
+
+ /* use OR instead of assignment to avoid clearing of bits in mask */
+ if (pfmemalloc)
+ skb->pfmemalloc = 1;
+ skb->head_frag = 1;
+
+skb_success:
+ skb_reserve(skb, NET_SKB_PAD);
+ skb->dev = dev;
+
+skb_fail:
+ return skb;
+}
+EXPORT_SYMBOL(__netdev_alloc_skb);
+
+/**
+ * __napi_alloc_skb - allocate skbuff for rx in a specific NAPI instance
+ * @napi: napi instance this buffer was allocated for
+ * @len: length to allocate
+ * @gfp_mask: get_free_pages mask, passed to alloc_skb and alloc_pages
+ *
+ * Allocate a new sk_buff for use in NAPI receive. This buffer will
+ * attempt to allocate the head from a special reserved region used
+ * only for NAPI Rx allocation. By doing this we can save several
+ * CPU cycles by avoiding having to disable and re-enable IRQs.
+ *
+ * %NULL is returned if there is no free memory.
+ */
+struct sk_buff *__napi_alloc_skb(struct napi_struct *napi, unsigned int len,
+ gfp_t gfp_mask)
+{
+ struct napi_alloc_cache *nc;
+ struct sk_buff *skb;
+ void *data;
+
+ len += NET_SKB_PAD + NET_IP_ALIGN;
+
+ /* If requested length is either too small or too big,
+ * we use kmalloc() for skb->head allocation.
+ */
+ if (len <= SKB_WITH_OVERHEAD(1024) ||
+ len > SKB_WITH_OVERHEAD(PAGE_SIZE) ||
+ (gfp_mask & (__GFP_DIRECT_RECLAIM | GFP_DMA))) {
+ skb = __alloc_skb(len, gfp_mask, SKB_ALLOC_RX, NUMA_NO_NODE);
+ if (!skb)
+ goto skb_fail;
+ goto skb_success;
+ }
+
+ nc = this_cpu_ptr(&napi_alloc_cache);
+ len += SKB_DATA_ALIGN(sizeof(struct skb_shared_info));
+ len = SKB_DATA_ALIGN(len);
+
+ if (sk_memalloc_socks())
+ gfp_mask |= __GFP_MEMALLOC;
+
+ data = page_frag_alloc(&nc->page, len, gfp_mask);
+ if (unlikely(!data))
+ return NULL;
+
+ skb = __build_skb(data, len);
+ if (unlikely(!skb)) {
+ skb_free_frag(data);
+ return NULL;
+ }
+
+ /* use OR instead of assignment to avoid clearing of bits in mask */
+ if (nc->page.pfmemalloc)
+ skb->pfmemalloc = 1;
+ skb->head_frag = 1;
+
+skb_success:
+ skb_reserve(skb, NET_SKB_PAD + NET_IP_ALIGN);
+ skb->dev = napi->dev;
+
+skb_fail:
+ return skb;
+}
+EXPORT_SYMBOL(__napi_alloc_skb);
+
+struct sk_buff *__netdev_alloc_skb_ip_align(struct net_device *dev,
+ unsigned int length, gfp_t gfp)
+{
+ struct sk_buff *skb = __netdev_alloc_skb(dev, length + NET_IP_ALIGN, gfp);
+
+#ifdef CONFIG_ETHERNET_PACKET_MANGLE
+ if (dev && (dev->priv_flags & IFF_NO_IP_ALIGN))
+ return skb;
+#endif
+
+ if (NET_IP_ALIGN && skb)
+ skb_reserve(skb, NET_IP_ALIGN);
+ return skb;
+}
+EXPORT_SYMBOL(__netdev_alloc_skb_ip_align);
+
+void skb_add_rx_frag(struct sk_buff *skb, int i, struct page *page, int off,
+ int size, unsigned int truesize)
+{
+ skb_fill_page_desc(skb, i, page, off, size);
+ skb->len += size;
+ skb->data_len += size;
+ skb->truesize += truesize;
+}
+EXPORT_SYMBOL(skb_add_rx_frag);
+
+void skb_coalesce_rx_frag(struct sk_buff *skb, int i, int size,
+ unsigned int truesize)
+{
+ skb_frag_t *frag = &skb_shinfo(skb)->frags[i];
+
+ skb_frag_size_add(frag, size);
+ skb->len += size;
+ skb->data_len += size;
+ skb->truesize += truesize;
+}
+EXPORT_SYMBOL(skb_coalesce_rx_frag);
+
+static void skb_drop_list(struct sk_buff **listp)
+{
+ kfree_skb_list(*listp);
+ *listp = NULL;
+}
+
+static inline void skb_drop_fraglist(struct sk_buff *skb)
+{
+ skb_drop_list(&skb_shinfo(skb)->frag_list);
+}
+
+static void skb_clone_fraglist(struct sk_buff *skb)
+{
+ struct sk_buff *list;
+
+ skb_walk_frags(skb, list)
+ skb_get(list);
+}
+
+static void skb_free_head(struct sk_buff *skb)
+{
+ unsigned char *head;
+#ifdef CONFIG_ASR_BM
+ bool cached_head = false;
+#endif
+
+ if (skb_shinfo_is_ptr(skb)) {
+#ifdef CONFIG_ASR_BM
+ /* in case of normal case & skb clone */
+ if (skb->cached_head)
+ cached_head = true;
+#endif
+
+ skb_p_revert(skb);
+ }
+
+#ifdef CONFIG_ASR_BM
+ if (cached_head)
+ return;
+#endif
+
+ head = skb->head;
+ if (skb->head_frag)
+ skb_free_frag(head);
+ else
+ kfree(head);
+}
+
+static void skb_release_data(struct sk_buff *skb)
+{
+ struct skb_shared_info *shinfo = skb_shinfo(skb);
+ int i;
+
+ if (skb->cloned &&
+ atomic_sub_return(skb->nohdr ? (1 << SKB_DATAREF_SHIFT) + 1 : 1,
+ &shinfo->dataref))
+ return;
+
+ for (i = 0; i < shinfo->nr_frags; i++)
+ __skb_frag_unref(&shinfo->frags[i]);
+
+ if (shinfo->frag_list)
+ kfree_skb_list(shinfo->frag_list);
+
+ skb_zcopy_clear(skb, true);
+ skb_free_head(skb);
+}
+
+/*
+ * Free an skbuff by memory without cleaning the state.
+ */
+static void kfree_skbmem(struct sk_buff *skb)
+{
+ struct sk_buff_fclones *fclones;
+
+#ifdef CONFIG_ASR_BM
+ if (skb->cached_skb) {
+ bm_cache_skb_free(skb);
+ return;
+ }
+#endif
+
+ switch (skb->fclone) {
+ case SKB_FCLONE_UNAVAILABLE:
+ kmem_cache_free(skbuff_head_cache, skb);
+ return;
+
+ case SKB_FCLONE_ORIG:
+ fclones = container_of(skb, struct sk_buff_fclones, skb1);
+
+ /* We usually free the clone (TX completion) before original skb
+ * This test would have no chance to be true for the clone,
+ * while here, branch prediction will be good.
+ */
+ if (refcount_read(&fclones->fclone_ref) == 1)
+ goto fastpath;
+ break;
+
+ default: /* SKB_FCLONE_CLONE */
+ fclones = container_of(skb, struct sk_buff_fclones, skb2);
+ break;
+ }
+ if (!refcount_dec_and_test(&fclones->fclone_ref))
+ return;
+fastpath:
+ kmem_cache_free(skbuff_fclone_cache, fclones);
+}
+
+void skb_release_head_state(struct sk_buff *skb)
+{
+ skb_dst_drop(skb);
+ if (skb->destructor) {
+ WARN_ON(in_irq());
+ skb->destructor(skb);
+ }
+#if IS_ENABLED(CONFIG_NF_CONNTRACK)
+ nf_conntrack_put(skb_nfct(skb));
+#endif
+ skb_ext_put(skb);
+}
+
+/* Free everything but the sk_buff shell. */
+static void skb_release_all(struct sk_buff *skb)
+{
+ skb_release_head_state(skb);
+ if (likely(skb->head))
+ skb_release_data(skb);
+}
+
+/**
+ * __kfree_skb - private function
+ * @skb: buffer
+ *
+ * Free an sk_buff. Release anything attached to the buffer.
+ * Clean the state. This is an internal helper function. Users should
+ * always call kfree_skb
+ */
+
+void __kfree_skb(struct sk_buff *skb)
+{
+ skb_release_all(skb);
+ kfree_skbmem(skb);
+}
+EXPORT_SYMBOL(__kfree_skb);
+
+/**
+ * kfree_skb - free an sk_buff
+ * @skb: buffer to free
+ *
+ * Drop a reference to the buffer and free it if the usage count has
+ * hit zero.
+ */
+void kfree_skb(struct sk_buff *skb)
+{
+ if (!skb_unref(skb))
+ return;
+
+ trace_android_vh_kfree_skb(skb);
+ trace_kfree_skb(skb, __builtin_return_address(0));
+ __kfree_skb(skb);
+}
+EXPORT_SYMBOL(kfree_skb);
+
+void kfree_skb_list(struct sk_buff *segs)
+{
+ while (segs) {
+ struct sk_buff *next = segs->next;
+
+ kfree_skb(segs);
+ segs = next;
+ }
+}
+EXPORT_SYMBOL(kfree_skb_list);
+
+/* Dump skb information and contents.
+ *
+ * Must only be called from net_ratelimit()-ed paths.
+ *
+ * Dumps up to can_dump_full whole packets if full_pkt, headers otherwise.
+ */
+void skb_dump(const char *level, const struct sk_buff *skb, bool full_pkt)
+{
+ static atomic_t can_dump_full = ATOMIC_INIT(5);
+ struct skb_shared_info *sh = skb_shinfo(skb);
+ struct net_device *dev = skb->dev;
+ struct sock *sk = skb->sk;
+ struct sk_buff *list_skb;
+ bool has_mac, has_trans;
+ int headroom, tailroom;
+ int i, len, seg_len;
+
+ if (full_pkt)
+ full_pkt = atomic_dec_if_positive(&can_dump_full) >= 0;
+
+ if (full_pkt)
+ len = skb->len;
+ else
+ len = min_t(int, skb->len, MAX_HEADER + 128);
+
+ headroom = skb_headroom(skb);
+ tailroom = skb_tailroom(skb);
+
+ has_mac = skb_mac_header_was_set(skb);
+ has_trans = skb_transport_header_was_set(skb);
+
+ printk("%sskb len=%u headroom=%u headlen=%u tailroom=%u\n"
+ "mac=(%d,%d) net=(%d,%d) trans=%d\n"
+ "shinfo(txflags=%u nr_frags=%u gso(size=%hu type=%u segs=%hu))\n"
+ "csum(0x%x ip_summed=%u complete_sw=%u valid=%u level=%u)\n"
+ "hash(0x%x sw=%u l4=%u) proto=0x%04x pkttype=%u iif=%d\n",
+ level, skb->len, headroom, skb_headlen(skb), tailroom,
+ has_mac ? skb->mac_header : -1,
+ has_mac ? skb_mac_header_len(skb) : -1,
+ skb->network_header,
+ has_trans ? skb_network_header_len(skb) : -1,
+ has_trans ? skb->transport_header : -1,
+ sh->tx_flags, sh->nr_frags,
+ sh->gso_size, sh->gso_type, sh->gso_segs,
+ skb->csum, skb->ip_summed, skb->csum_complete_sw,
+ skb->csum_valid, skb->csum_level,
+ skb->hash, skb->sw_hash, skb->l4_hash,
+ ntohs(skb->protocol), skb->pkt_type, skb->skb_iif);
+
+ if (dev)
+ printk("%sdev name=%s feat=%pNF\n",
+ level, dev->name, &dev->features);
+ if (sk)
+ printk("%ssk family=%hu type=%u proto=%u\n",
+ level, sk->sk_family, sk->sk_type, sk->sk_protocol);
+
+ if (full_pkt && headroom)
+ print_hex_dump(level, "skb headroom: ", DUMP_PREFIX_OFFSET,
+ 16, 1, skb->head, headroom, false);
+
+ seg_len = min_t(int, skb_headlen(skb), len);
+ if (seg_len)
+ print_hex_dump(level, "skb linear: ", DUMP_PREFIX_OFFSET,
+ 16, 1, skb->data, seg_len, false);
+ len -= seg_len;
+
+ if (full_pkt && tailroom)
+ print_hex_dump(level, "skb tailroom: ", DUMP_PREFIX_OFFSET,
+ 16, 1, skb_tail_pointer(skb), tailroom, false);
+
+ for (i = 0; len && i < skb_shinfo(skb)->nr_frags; i++) {
+ skb_frag_t *frag = &skb_shinfo(skb)->frags[i];
+ u32 p_off, p_len, copied;
+ struct page *p;
+ u8 *vaddr;
+
+ skb_frag_foreach_page(frag, skb_frag_off(frag),
+ skb_frag_size(frag), p, p_off, p_len,
+ copied) {
+ seg_len = min_t(int, p_len, len);
+ vaddr = kmap_atomic(p);
+ print_hex_dump(level, "skb frag: ",
+ DUMP_PREFIX_OFFSET,
+ 16, 1, vaddr + p_off, seg_len, false);
+ kunmap_atomic(vaddr);
+ len -= seg_len;
+ if (!len)
+ break;
+ }
+ }
+
+ if (full_pkt && skb_has_frag_list(skb)) {
+ printk("skb fraglist:\n");
+ skb_walk_frags(skb, list_skb)
+ skb_dump(level, list_skb, true);
+ }
+}
+EXPORT_SYMBOL(skb_dump);
+
+/**
+ * skb_tx_error - report an sk_buff xmit error
+ * @skb: buffer that triggered an error
+ *
+ * Report xmit error if a device callback is tracking this skb.
+ * skb must be freed afterwards.
+ */
+void skb_tx_error(struct sk_buff *skb)
+{
+ skb_zcopy_clear(skb, true);
+}
+EXPORT_SYMBOL(skb_tx_error);
+
+/**
+ * consume_skb - free an skbuff
+ * @skb: buffer to free
+ *
+ * Drop a ref to the buffer and free it if the usage count has hit zero
+ * Functions identically to kfree_skb, but kfree_skb assumes that the frame
+ * is being dropped after a failure and notes that
+ */
+void consume_skb(struct sk_buff *skb)
+{
+ if (!skb_unref(skb))
+ return;
+
+ trace_consume_skb(skb);
+ __kfree_skb(skb);
+}
+EXPORT_SYMBOL(consume_skb);
+
+/**
+ * consume_stateless_skb - free an skbuff, assuming it is stateless
+ * @skb: buffer to free
+ *
+ * Alike consume_skb(), but this variant assumes that this is the last
+ * skb reference and all the head states have been already dropped
+ */
+void __consume_stateless_skb(struct sk_buff *skb)
+{
+ trace_consume_skb(skb);
+ skb_release_data(skb);
+ kfree_skbmem(skb);
+}
+
+void __kfree_skb_flush(void)
+{
+ struct napi_alloc_cache *nc = this_cpu_ptr(&napi_alloc_cache);
+
+ /* flush skb_cache if containing objects */
+ if (nc->skb_count) {
+ kmem_cache_free_bulk(skbuff_head_cache, nc->skb_count,
+ nc->skb_cache);
+ nc->skb_count = 0;
+ }
+}
+
+static inline void _kfree_skb_defer(struct sk_buff *skb)
+{
+ struct napi_alloc_cache *nc = this_cpu_ptr(&napi_alloc_cache);
+
+ /* drop skb->head and call any destructors for packet */
+ skb_release_all(skb);
+
+#ifdef CONFIG_ASR_BM
+ if (skb->cached_skb) {
+ bm_cache_skb_free(skb);
+ return;
+ }
+#endif
+
+ /* record skb to CPU local list */
+ nc->skb_cache[nc->skb_count++] = skb;
+
+#ifdef CONFIG_SLUB
+ /* SLUB writes into objects when freeing */
+ prefetchw(skb);
+#endif
+
+ /* flush skb_cache if it is filled */
+ if (unlikely(nc->skb_count == NAPI_SKB_CACHE_SIZE)) {
+ kmem_cache_free_bulk(skbuff_head_cache, NAPI_SKB_CACHE_SIZE,
+ nc->skb_cache);
+ nc->skb_count = 0;
+ }
+}
+void __kfree_skb_defer(struct sk_buff *skb)
+{
+ _kfree_skb_defer(skb);
+}
+
+void napi_consume_skb(struct sk_buff *skb, int budget)
+{
+ if (unlikely(!skb))
+ return;
+
+ /* Zero budget indicate non-NAPI context called us, like netpoll */
+ if (unlikely(!budget)) {
+ dev_consume_skb_any(skb);
+ return;
+ }
+
+ if (!skb_unref(skb))
+ return;
+
+ /* if reaching here SKB is ready to free */
+ trace_consume_skb(skb);
+
+ /* if SKB is a clone, don't handle this case */
+ if (skb->fclone != SKB_FCLONE_UNAVAILABLE) {
+ __kfree_skb(skb);
+ return;
+ }
+
+ _kfree_skb_defer(skb);
+}
+EXPORT_SYMBOL(napi_consume_skb);
+
+/* Make sure a field is enclosed inside headers_start/headers_end section */
+#define CHECK_SKB_FIELD(field) \
+ BUILD_BUG_ON(offsetof(struct sk_buff, field) < \
+ offsetof(struct sk_buff, headers_start)); \
+ BUILD_BUG_ON(offsetof(struct sk_buff, field) > \
+ offsetof(struct sk_buff, headers_end)); \
+
+static void __copy_skb_header(struct sk_buff *new, const struct sk_buff *old)
+{
+ new->tstamp = old->tstamp;
+ /* We do not copy old->sk */
+ new->dev = old->dev;
+ memcpy(new->cb, old->cb, sizeof(old->cb));
+ skb_dst_copy(new, old);
+ __skb_ext_copy(new, old);
+ __nf_copy(new, old, false);
+
+ /* Note : this field could be in headers_start/headers_end section
+ * It is not yet because we do not want to have a 16 bit hole
+ */
+ new->queue_mapping = old->queue_mapping;
+
+ memcpy(&new->headers_start, &old->headers_start,
+ offsetof(struct sk_buff, headers_end) -
+ offsetof(struct sk_buff, headers_start));
+ CHECK_SKB_FIELD(protocol);
+ CHECK_SKB_FIELD(csum);
+ CHECK_SKB_FIELD(hash);
+ CHECK_SKB_FIELD(priority);
+ CHECK_SKB_FIELD(skb_iif);
+ CHECK_SKB_FIELD(vlan_proto);
+ CHECK_SKB_FIELD(vlan_tci);
+ CHECK_SKB_FIELD(transport_header);
+ CHECK_SKB_FIELD(network_header);
+ CHECK_SKB_FIELD(mac_header);
+ CHECK_SKB_FIELD(inner_protocol);
+ CHECK_SKB_FIELD(inner_transport_header);
+ CHECK_SKB_FIELD(inner_network_header);
+ CHECK_SKB_FIELD(inner_mac_header);
+ CHECK_SKB_FIELD(mark);
+#ifdef CONFIG_NETWORK_SECMARK
+ CHECK_SKB_FIELD(secmark);
+#endif
+#ifdef CONFIG_NET_RX_BUSY_POLL
+ CHECK_SKB_FIELD(napi_id);
+#endif
+#ifdef CONFIG_XPS
+ CHECK_SKB_FIELD(sender_cpu);
+#endif
+#ifdef CONFIG_NET_SCHED
+ CHECK_SKB_FIELD(tc_index);
+#endif
+
+}
+
+/*
+ * You should not add any new code to this function. Add it to
+ * __copy_skb_header above instead.
+ */
+static struct sk_buff *__skb_clone(struct sk_buff *n, struct sk_buff *skb)
+{
+#define C(x) n->x = skb->x
+
+ n->next = n->prev = NULL;
+ n->sk = NULL;
+ __copy_skb_header(n, skb);
+
+ C(len);
+ C(data_len);
+ C(mac_len);
+ n->hdr_len = skb->nohdr ? skb_headroom(skb) : skb->hdr_len;
+ n->cloned = 1;
+ n->nohdr = 0;
+ n->peeked = 0;
+ C(pfmemalloc);
+ n->destructor = NULL;
+ C(tail);
+ C(end);
+ C(head);
+ C(head_frag);
+ C(data);
+ C(truesize);
+ C(shared_info_ptr);
+#ifdef CONFIG_ASR_BM
+ C(cached_head);
+ n->cached_skb = 0;
+ n->in_use = 0;
+ n->rsvd = 0;
+#endif
+ refcount_set(&n->users, 1);
+
+ atomic_inc(&(skb_shinfo(skb)->dataref));
+ skb->cloned = 1;
+
+ return n;
+#undef C
+}
+
+/**
+ * alloc_skb_for_msg() - allocate sk_buff to wrap frag list forming a msg
+ * @first: first sk_buff of the msg
+ */
+struct sk_buff *alloc_skb_for_msg(struct sk_buff *first)
+{
+ struct sk_buff *n;
+
+ n = alloc_skb(0, GFP_ATOMIC);
+ if (!n)
+ return NULL;
+
+ n->len = first->len;
+ n->data_len = first->len;
+ n->truesize = first->truesize;
+
+ skb_shinfo(n)->frag_list = first;
+
+ __copy_skb_header(n, first);
+ n->destructor = NULL;
+
+ return n;
+}
+EXPORT_SYMBOL_GPL(alloc_skb_for_msg);
+
+/**
+ * skb_morph - morph one skb into another
+ * @dst: the skb to receive the contents
+ * @src: the skb to supply the contents
+ *
+ * This is identical to skb_clone except that the target skb is
+ * supplied by the user.
+ *
+ * The target skb is returned upon exit.
+ */
+struct sk_buff *skb_morph(struct sk_buff *dst, struct sk_buff *src)
+{
+ skb_release_all(dst);
+ return __skb_clone(dst, src);
+}
+EXPORT_SYMBOL_GPL(skb_morph);
+
+int mm_account_pinned_pages(struct mmpin *mmp, size_t size)
+{
+ unsigned long max_pg, num_pg, new_pg, old_pg;
+ struct user_struct *user;
+
+ if (capable(CAP_IPC_LOCK) || !size)
+ return 0;
+
+ num_pg = (size >> PAGE_SHIFT) + 2; /* worst case */
+ max_pg = rlimit(RLIMIT_MEMLOCK) >> PAGE_SHIFT;
+ user = mmp->user ? : current_user();
+
+ do {
+ old_pg = atomic_long_read(&user->locked_vm);
+ new_pg = old_pg + num_pg;
+ if (new_pg > max_pg)
+ return -ENOBUFS;
+ } while (atomic_long_cmpxchg(&user->locked_vm, old_pg, new_pg) !=
+ old_pg);
+
+ if (!mmp->user) {
+ mmp->user = get_uid(user);
+ mmp->num_pg = num_pg;
+ } else {
+ mmp->num_pg += num_pg;
+ }
+
+ return 0;
+}
+EXPORT_SYMBOL_GPL(mm_account_pinned_pages);
+
+void mm_unaccount_pinned_pages(struct mmpin *mmp)
+{
+ if (mmp->user) {
+ atomic_long_sub(mmp->num_pg, &mmp->user->locked_vm);
+ free_uid(mmp->user);
+ }
+}
+EXPORT_SYMBOL_GPL(mm_unaccount_pinned_pages);
+
+struct ubuf_info *sock_zerocopy_alloc(struct sock *sk, size_t size)
+{
+ struct ubuf_info *uarg;
+ struct sk_buff *skb;
+
+ WARN_ON_ONCE(!in_task());
+
+ skb = sock_omalloc(sk, 0, GFP_KERNEL);
+ if (!skb)
+ return NULL;
+
+ BUILD_BUG_ON(sizeof(*uarg) > sizeof(skb->cb));
+ uarg = (void *)skb->cb;
+ uarg->mmp.user = NULL;
+
+ if (mm_account_pinned_pages(&uarg->mmp, size)) {
+ kfree_skb(skb);
+ return NULL;
+ }
+
+ uarg->callback = sock_zerocopy_callback;
+ uarg->id = ((u32)atomic_inc_return(&sk->sk_zckey)) - 1;
+ uarg->len = 1;
+ uarg->bytelen = size;
+ uarg->zerocopy = 1;
+ refcount_set(&uarg->refcnt, 1);
+ sock_hold(sk);
+
+ return uarg;
+}
+EXPORT_SYMBOL_GPL(sock_zerocopy_alloc);
+
+static inline struct sk_buff *skb_from_uarg(struct ubuf_info *uarg)
+{
+ return container_of((void *)uarg, struct sk_buff, cb);
+}
+
+struct ubuf_info *sock_zerocopy_realloc(struct sock *sk, size_t size,
+ struct ubuf_info *uarg)
+{
+ if (uarg) {
+ const u32 byte_limit = 1 << 19; /* limit to a few TSO */
+ u32 bytelen, next;
+
+ /* realloc only when socket is locked (TCP, UDP cork),
+ * so uarg->len and sk_zckey access is serialized
+ */
+ if (!sock_owned_by_user(sk)) {
+ WARN_ON_ONCE(1);
+ return NULL;
+ }
+
+ bytelen = uarg->bytelen + size;
+ if (uarg->len == USHRT_MAX - 1 || bytelen > byte_limit) {
+ /* TCP can create new skb to attach new uarg */
+ if (sk->sk_type == SOCK_STREAM)
+ goto new_alloc;
+ return NULL;
+ }
+
+ next = (u32)atomic_read(&sk->sk_zckey);
+ if ((u32)(uarg->id + uarg->len) == next) {
+ if (mm_account_pinned_pages(&uarg->mmp, size))
+ return NULL;
+ uarg->len++;
+ uarg->bytelen = bytelen;
+ atomic_set(&sk->sk_zckey, ++next);
+
+ /* no extra ref when appending to datagram (MSG_MORE) */
+ if (sk->sk_type == SOCK_STREAM)
+ sock_zerocopy_get(uarg);
+
+ return uarg;
+ }
+ }
+
+new_alloc:
+ return sock_zerocopy_alloc(sk, size);
+}
+EXPORT_SYMBOL_GPL(sock_zerocopy_realloc);
+
+static bool skb_zerocopy_notify_extend(struct sk_buff *skb, u32 lo, u16 len)
+{
+ struct sock_exterr_skb *serr = SKB_EXT_ERR(skb);
+ u32 old_lo, old_hi;
+ u64 sum_len;
+
+ old_lo = serr->ee.ee_info;
+ old_hi = serr->ee.ee_data;
+ sum_len = old_hi - old_lo + 1ULL + len;
+
+ if (sum_len >= (1ULL << 32))
+ return false;
+
+ if (lo != old_hi + 1)
+ return false;
+
+ serr->ee.ee_data += len;
+ return true;
+}
+
+void sock_zerocopy_callback(struct ubuf_info *uarg, bool success)
+{
+ struct sk_buff *tail, *skb = skb_from_uarg(uarg);
+ struct sock_exterr_skb *serr;
+ struct sock *sk = skb->sk;
+ struct sk_buff_head *q;
+ unsigned long flags;
+ u32 lo, hi;
+ u16 len;
+
+ mm_unaccount_pinned_pages(&uarg->mmp);
+
+ /* if !len, there was only 1 call, and it was aborted
+ * so do not queue a completion notification
+ */
+ if (!uarg->len || sock_flag(sk, SOCK_DEAD))
+ goto release;
+
+ len = uarg->len;
+ lo = uarg->id;
+ hi = uarg->id + len - 1;
+
+ serr = SKB_EXT_ERR(skb);
+ memset(serr, 0, sizeof(*serr));
+ serr->ee.ee_errno = 0;
+ serr->ee.ee_origin = SO_EE_ORIGIN_ZEROCOPY;
+ serr->ee.ee_data = hi;
+ serr->ee.ee_info = lo;
+ if (!success)
+ serr->ee.ee_code |= SO_EE_CODE_ZEROCOPY_COPIED;
+
+ q = &sk->sk_error_queue;
+ spin_lock_irqsave(&q->lock, flags);
+ tail = skb_peek_tail(q);
+ if (!tail || SKB_EXT_ERR(tail)->ee.ee_origin != SO_EE_ORIGIN_ZEROCOPY ||
+ !skb_zerocopy_notify_extend(tail, lo, len)) {
+ __skb_queue_tail(q, skb);
+ skb = NULL;
+ }
+ spin_unlock_irqrestore(&q->lock, flags);
+
+ sk->sk_error_report(sk);
+
+release:
+ consume_skb(skb);
+ sock_put(sk);
+}
+EXPORT_SYMBOL_GPL(sock_zerocopy_callback);
+
+void sock_zerocopy_put(struct ubuf_info *uarg)
+{
+ if (uarg && refcount_dec_and_test(&uarg->refcnt)) {
+ if (uarg->callback)
+ uarg->callback(uarg, uarg->zerocopy);
+ else
+ consume_skb(skb_from_uarg(uarg));
+ }
+}
+EXPORT_SYMBOL_GPL(sock_zerocopy_put);
+
+void sock_zerocopy_put_abort(struct ubuf_info *uarg, bool have_uref)
+{
+ if (uarg) {
+ struct sock *sk = skb_from_uarg(uarg)->sk;
+
+ atomic_dec(&sk->sk_zckey);
+ uarg->len--;
+
+ if (have_uref)
+ sock_zerocopy_put(uarg);
+ }
+}
+EXPORT_SYMBOL_GPL(sock_zerocopy_put_abort);
+
+int skb_zerocopy_iter_dgram(struct sk_buff *skb, struct msghdr *msg, int len)
+{
+ return __zerocopy_sg_from_iter(skb->sk, skb, &msg->msg_iter, len);
+}
+EXPORT_SYMBOL_GPL(skb_zerocopy_iter_dgram);
+
+int skb_zerocopy_iter_stream(struct sock *sk, struct sk_buff *skb,
+ struct msghdr *msg, int len,
+ struct ubuf_info *uarg)
+{
+ struct ubuf_info *orig_uarg = skb_zcopy(skb);
+ struct iov_iter orig_iter = msg->msg_iter;
+ int err, orig_len = skb->len;
+
+ /* An skb can only point to one uarg. This edge case happens when
+ * TCP appends to an skb, but zerocopy_realloc triggered a new alloc.
+ */
+ if (orig_uarg && uarg != orig_uarg)
+ return -EEXIST;
+
+ err = __zerocopy_sg_from_iter(sk, skb, &msg->msg_iter, len);
+ if (err == -EFAULT || (err == -EMSGSIZE && skb->len == orig_len)) {
+ struct sock *save_sk = skb->sk;
+
+ /* Streams do not free skb on error. Reset to prev state. */
+ msg->msg_iter = orig_iter;
+ skb->sk = sk;
+ ___pskb_trim(skb, orig_len);
+ skb->sk = save_sk;
+ return err;
+ }
+
+ skb_zcopy_set(skb, uarg, NULL);
+ return skb->len - orig_len;
+}
+EXPORT_SYMBOL_GPL(skb_zerocopy_iter_stream);
+
+static int skb_zerocopy_clone(struct sk_buff *nskb, struct sk_buff *orig,
+ gfp_t gfp_mask)
+{
+ if (skb_zcopy(orig)) {
+ if (skb_zcopy(nskb)) {
+ /* !gfp_mask callers are verified to !skb_zcopy(nskb) */
+ if (!gfp_mask) {
+ WARN_ON_ONCE(1);
+ return -ENOMEM;
+ }
+ if (skb_uarg(nskb) == skb_uarg(orig))
+ return 0;
+ if (skb_copy_ubufs(nskb, GFP_ATOMIC))
+ return -EIO;
+ }
+ skb_zcopy_set(nskb, skb_uarg(orig), NULL);
+ }
+ return 0;
+}
+
+/**
+ * skb_copy_ubufs - copy userspace skb frags buffers to kernel
+ * @skb: the skb to modify
+ * @gfp_mask: allocation priority
+ *
+ * This must be called on SKBTX_DEV_ZEROCOPY skb.
+ * It will copy all frags into kernel and drop the reference
+ * to userspace pages.
+ *
+ * If this function is called from an interrupt gfp_mask() must be
+ * %GFP_ATOMIC.
+ *
+ * Returns 0 on success or a negative error code on failure
+ * to allocate kernel memory to copy to.
+ */
+int skb_copy_ubufs(struct sk_buff *skb, gfp_t gfp_mask)
+{
+ int num_frags = skb_shinfo(skb)->nr_frags;
+ struct page *page, *head = NULL;
+ int i, new_frags;
+ u32 d_off;
+
+ if (skb_shared(skb) || skb_unclone(skb, gfp_mask))
+ return -EINVAL;
+
+ if (!num_frags)
+ goto release;
+
+ new_frags = (__skb_pagelen(skb) + PAGE_SIZE - 1) >> PAGE_SHIFT;
+ for (i = 0; i < new_frags; i++) {
+ page = alloc_page(gfp_mask);
+ if (!page) {
+ while (head) {
+ struct page *next = (struct page *)page_private(head);
+ put_page(head);
+ head = next;
+ }
+ return -ENOMEM;
+ }
+ set_page_private(page, (unsigned long)head);
+ head = page;
+ }
+
+ page = head;
+ d_off = 0;
+ for (i = 0; i < num_frags; i++) {
+ skb_frag_t *f = &skb_shinfo(skb)->frags[i];
+ u32 p_off, p_len, copied;
+ struct page *p;
+ u8 *vaddr;
+
+ skb_frag_foreach_page(f, skb_frag_off(f), skb_frag_size(f),
+ p, p_off, p_len, copied) {
+ u32 copy, done = 0;
+ vaddr = kmap_atomic(p);
+
+ while (done < p_len) {
+ if (d_off == PAGE_SIZE) {
+ d_off = 0;
+ page = (struct page *)page_private(page);
+ }
+ copy = min_t(u32, PAGE_SIZE - d_off, p_len - done);
+ memcpy(page_address(page) + d_off,
+ vaddr + p_off + done, copy);
+ done += copy;
+ d_off += copy;
+ }
+ kunmap_atomic(vaddr);
+ }
+ }
+
+ /* skb frags release userspace buffers */
+ for (i = 0; i < num_frags; i++)
+ skb_frag_unref(skb, i);
+
+ /* skb frags point to kernel buffers */
+ for (i = 0; i < new_frags - 1; i++) {
+ __skb_fill_page_desc(skb, i, head, 0, PAGE_SIZE);
+ head = (struct page *)page_private(head);
+ }
+ __skb_fill_page_desc(skb, new_frags - 1, head, 0, d_off);
+ skb_shinfo(skb)->nr_frags = new_frags;
+
+release:
+ skb_zcopy_clear(skb, false);
+ return 0;
+}
+EXPORT_SYMBOL_GPL(skb_copy_ubufs);
+
+/**
+ * skb_clone - duplicate an sk_buff
+ * @skb: buffer to clone
+ * @gfp_mask: allocation priority
+ *
+ * Duplicate an &sk_buff. The new one is not owned by a socket. Both
+ * copies share the same packet data but not structure. The new
+ * buffer has a reference count of 1. If the allocation fails the
+ * function returns %NULL otherwise the new buffer is returned.
+ *
+ * If this function is called from an interrupt gfp_mask() must be
+ * %GFP_ATOMIC.
+ */
+
+struct sk_buff *skb_clone(struct sk_buff *skb, gfp_t gfp_mask)
+{
+ struct sk_buff_fclones *fclones = container_of(skb,
+ struct sk_buff_fclones,
+ skb1);
+ struct sk_buff *n;
+
+ if (skb_orphan_frags(skb, gfp_mask))
+ return NULL;
+
+ if (skb->fclone == SKB_FCLONE_ORIG &&
+ refcount_read(&fclones->fclone_ref) == 1) {
+ n = &fclones->skb2;
+ refcount_set(&fclones->fclone_ref, 2);
+ } else {
+ if (skb_pfmemalloc(skb))
+ gfp_mask |= __GFP_MEMALLOC;
+
+ n = kmem_cache_alloc(skbuff_head_cache, gfp_mask);
+ if (!n)
+ return NULL;
+
+ n->fclone = SKB_FCLONE_UNAVAILABLE;
+ }
+
+ return __skb_clone(n, skb);
+}
+EXPORT_SYMBOL(skb_clone);
+
+void skb_headers_offset_update(struct sk_buff *skb, int off)
+{
+ /* Only adjust this if it actually is csum_start rather than csum */
+ if (skb->ip_summed == CHECKSUM_PARTIAL)
+ skb->csum_start += off;
+ /* {transport,network,mac}_header and tail are relative to skb->head */
+ skb->transport_header += off;
+ skb->network_header += off;
+ if (skb_mac_header_was_set(skb))
+ skb->mac_header += off;
+ skb->inner_transport_header += off;
+ skb->inner_network_header += off;
+ skb->inner_mac_header += off;
+}
+EXPORT_SYMBOL(skb_headers_offset_update);
+
+static void skb_p_revert(struct sk_buff *skb)
+{
+ long off;
+
+ if (skb_shinfo(skb)->priv_free_func) {
+ skb_shinfo(skb)->priv_free_func(
+ skb_shinfo(skb)->priv_data,
+ skb->head, skb_end_offset(skb));
+ skb_shinfo(skb)->priv_free_func = NULL;
+ skb_shinfo(skb)->priv_data = NULL;
+ }
+
+ skb->truesize -= skb_end_offset(skb);
+
+ if (skb_shinfo(skb)->priv_head) {
+ off = skb_shinfo(skb)->priv_head - skb->head;
+ skb->head += off;
+ skb->data += off;
+#ifndef NET_SKBUFF_DATA_USES_OFFSET
+ skb->end += off;
+ skb->tail += off;
+#endif
+ skb_shinfo(skb)->priv_head = NULL;
+ }
+
+ skb->shared_info_ptr = NULL;
+}
+
+void skb_copy_header(struct sk_buff *new, const struct sk_buff *old)
+{
+ __copy_skb_header(new, old);
+
+ skb_shinfo(new)->gso_size = skb_shinfo(old)->gso_size;
+ skb_shinfo(new)->gso_segs = skb_shinfo(old)->gso_segs;
+ skb_shinfo(new)->gso_type = skb_shinfo(old)->gso_type;
+}
+EXPORT_SYMBOL(skb_copy_header);
+
+static inline int skb_alloc_rx_flag(const struct sk_buff *skb)
+{
+ if (skb_pfmemalloc(skb))
+ return SKB_ALLOC_RX;
+ return 0;
+}
+
+/**
+ * skb_copy - create private copy of an sk_buff
+ * @skb: buffer to copy
+ * @gfp_mask: allocation priority
+ *
+ * Make a copy of both an &sk_buff and its data. This is used when the
+ * caller wishes to modify the data and needs a private copy of the
+ * data to alter. Returns %NULL on failure or the pointer to the buffer
+ * on success. The returned buffer has a reference count of 1.
+ *
+ * As by-product this function converts non-linear &sk_buff to linear
+ * one, so that &sk_buff becomes completely private and caller is allowed
+ * to modify all the data of returned buffer. This means that this
+ * function is not recommended for use in circumstances when only
+ * header is going to be modified. Use pskb_copy() instead.
+ */
+
+struct sk_buff *skb_copy(const struct sk_buff *skb, gfp_t gfp_mask)
+{
+ int headerlen = skb_headroom(skb);
+ unsigned int size = skb_end_offset(skb) + skb->data_len;
+ struct sk_buff *n = __alloc_skb(size, gfp_mask,
+ skb_alloc_rx_flag(skb), NUMA_NO_NODE);
+
+ if (!n)
+ return NULL;
+
+ /* Set the data pointer */
+ skb_reserve(n, headerlen);
+ /* Set the tail pointer and length */
+ skb_put(n, skb->len);
+
+ BUG_ON(skb_copy_bits(skb, -headerlen, n->head, headerlen + skb->len));
+
+ skb_copy_header(n, skb);
+ return n;
+}
+EXPORT_SYMBOL(skb_copy);
+
+/**
+ * __pskb_copy_fclone - create copy of an sk_buff with private head.
+ * @skb: buffer to copy
+ * @headroom: headroom of new skb
+ * @gfp_mask: allocation priority
+ * @fclone: if true allocate the copy of the skb from the fclone
+ * cache instead of the head cache; it is recommended to set this
+ * to true for the cases where the copy will likely be cloned
+ *
+ * Make a copy of both an &sk_buff and part of its data, located
+ * in header. Fragmented data remain shared. This is used when
+ * the caller wishes to modify only header of &sk_buff and needs
+ * private copy of the header to alter. Returns %NULL on failure
+ * or the pointer to the buffer on success.
+ * The returned buffer has a reference count of 1.
+ */
+
+struct sk_buff *__pskb_copy_fclone(struct sk_buff *skb, int headroom,
+ gfp_t gfp_mask, bool fclone)
+{
+ unsigned int size = skb_headlen(skb) + headroom;
+ int flags;
+ struct sk_buff *n;
+
+ flags = skb_alloc_rx_flag(skb) | (fclone ? SKB_ALLOC_FCLONE : 0);
+ n = __alloc_skb(size, gfp_mask, flags, NUMA_NO_NODE);
+ if (!n)
+ goto out;
+
+ /* Set the data pointer */
+ skb_reserve(n, headroom);
+ /* Set the tail pointer and length */
+ skb_put(n, skb_headlen(skb));
+ /* Copy the bytes */
+ skb_copy_from_linear_data(skb, n->data, n->len);
+
+ n->truesize += skb->data_len;
+ n->data_len = skb->data_len;
+ n->len = skb->len;
+
+ if (skb_shinfo(skb)->nr_frags) {
+ int i;
+
+ if (skb_orphan_frags(skb, gfp_mask) ||
+ skb_zerocopy_clone(n, skb, gfp_mask)) {
+ kfree_skb(n);
+ n = NULL;
+ goto out;
+ }
+ for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
+ skb_shinfo(n)->frags[i] = skb_shinfo(skb)->frags[i];
+ skb_frag_ref(skb, i);
+ }
+ skb_shinfo(n)->nr_frags = i;
+ }
+
+ if (skb_has_frag_list(skb)) {
+ skb_shinfo(n)->frag_list = skb_shinfo(skb)->frag_list;
+ skb_clone_fraglist(n);
+ }
+
+ skb_copy_header(n, skb);
+out:
+ return n;
+}
+EXPORT_SYMBOL(__pskb_copy_fclone);
+
+/**
+ * pskb_expand_head - reallocate header of &sk_buff
+ * @skb: buffer to reallocate
+ * @nhead: room to add at head
+ * @ntail: room to add at tail
+ * @gfp_mask: allocation priority
+ *
+ * Expands (or creates identical copy, if @nhead and @ntail are zero)
+ * header of @skb. &sk_buff itself is not changed. &sk_buff MUST have
+ * reference count of 1. Returns zero in the case of success or error,
+ * if expansion failed. In the last case, &sk_buff is not changed.
+ *
+ * All the pointers pointing into skb header may change and must be
+ * reloaded after call to this function.
+ */
+
+int pskb_expand_head(struct sk_buff *skb, int nhead, int ntail,
+ gfp_t gfp_mask)
+{
+ int i, osize = skb_end_offset(skb);
+ int size = osize + nhead + ntail;
+ long off;
+ u8 *data;
+
+ BUG_ON(nhead < 0);
+
+ BUG_ON(skb_shared(skb));
+
+ size = SKB_DATA_ALIGN(size);
+
+ if (skb_pfmemalloc(skb))
+ gfp_mask |= __GFP_MEMALLOC;
+ data = kmalloc_reserve(size + SKB_DATA_ALIGN(sizeof(struct skb_shared_info)),
+ gfp_mask, NUMA_NO_NODE, NULL);
+ if (!data)
+ goto nodata;
+ size = SKB_WITH_OVERHEAD(ksize(data));
+
+ /* Copy only real data... and, alas, header. This should be
+ * optimized for the cases when header is void.
+ */
+ memcpy(data + nhead, skb->head, skb_tail_pointer(skb) - skb->head);
+
+ memcpy((struct skb_shared_info *)(data + size),
+ skb_shinfo(skb),
+ offsetof(struct skb_shared_info, frags[skb_shinfo(skb)->nr_frags]));
+
+ /*
+ * if shinfo is shared we must drop the old head gracefully, but if it
+ * is not we can just drop the old head and let the existing refcount
+ * be since all we did is relocate the values
+ */
+ if (skb_cloned(skb)) {
+ if (skb_orphan_frags(skb, gfp_mask))
+ goto nofrags;
+ if (skb_zcopy(skb))
+ refcount_inc(&skb_uarg(skb)->refcnt);
+ for (i = 0; i < skb_shinfo(skb)->nr_frags; i++)
+ skb_frag_ref(skb, i);
+
+ if (skb_has_frag_list(skb))
+ skb_clone_fraglist(skb);
+
+ skb_release_data(skb);
+ } else {
+ skb_free_head(skb);
+ }
+ off = (data + nhead) - skb->head;
+
+ skb->head = data;
+ skb->head_frag = 0;
+ skb->data += off;
+#ifdef NET_SKBUFF_DATA_USES_OFFSET
+ skb->end = size;
+ off = nhead;
+#else
+ skb->end = skb->head + size;
+#endif
+ skb->tail += off;
+ skb_headers_offset_update(skb, nhead);
+ skb->cloned = 0;
+ skb->hdr_len = 0;
+ skb->nohdr = 0;
+ skb->shared_info_ptr = NULL;
+
+ atomic_set(&skb_shinfo(skb)->dataref, 1);
+
+ skb_metadata_clear(skb);
+
+ /* It is not generally safe to change skb->truesize.
+ * For the moment, we really care of rx path, or
+ * when skb is orphaned (not attached to a socket).
+ */
+ if (!skb->sk || skb->destructor == sock_edemux)
+ skb->truesize += size - osize;
+
+ return 0;
+
+nofrags:
+ kfree(data);
+nodata:
+ return -ENOMEM;
+}
+EXPORT_SYMBOL(pskb_expand_head);
+
+/* Make private copy of skb with writable head and some headroom */
+
+struct sk_buff *skb_realloc_headroom(struct sk_buff *skb, unsigned int headroom)
+{
+ struct sk_buff *skb2;
+ int delta;
+
+ delta = headroom - skb_headroom(skb);
+ if (delta <= 0)
+ skb2 = pskb_copy(skb, GFP_ATOMIC);
+ else {
+ skb2 = skb_clone(skb, GFP_ATOMIC);
+ if (skb2 && pskb_expand_head(skb2, SKB_DATA_ALIGN(delta), 0,
+ GFP_ATOMIC)) {
+ kfree_skb(skb2);
+ skb2 = NULL;
+ }
+ }
+ return skb2;
+}
+EXPORT_SYMBOL(skb_realloc_headroom);
+
+/**
+ * skb_expand_head - reallocate header of &sk_buff
+ * @skb: buffer to reallocate
+ * @headroom: needed headroom
+ *
+ * Unlike skb_realloc_headroom, this one does not allocate a new skb
+ * if possible; copies skb->sk to new skb as needed
+ * and frees original skb in case of failures.
+ *
+ * It expect increased headroom and generates warning otherwise.
+ */
+
+struct sk_buff *skb_expand_head(struct sk_buff *skb, unsigned int headroom)
+{
+ int delta = headroom - skb_headroom(skb);
+ int osize = skb_end_offset(skb);
+ struct sock *sk = skb->sk;
+
+ if (WARN_ONCE(delta <= 0,
+ "%s is expecting an increase in the headroom", __func__))
+ return skb;
+
+ delta = SKB_DATA_ALIGN(delta);
+ /* pskb_expand_head() might crash, if skb is shared. */
+ if (skb_shared(skb) || !is_skb_wmem(skb)) {
+ struct sk_buff *nskb = skb_clone(skb, GFP_ATOMIC);
+
+ if (unlikely(!nskb))
+ goto fail;
+
+ if (sk)
+ skb_set_owner_w(nskb, sk);
+ consume_skb(skb);
+ skb = nskb;
+ }
+ if (pskb_expand_head(skb, delta, 0, GFP_ATOMIC))
+ goto fail;
+
+ if (sk && is_skb_wmem(skb)) {
+ delta = skb_end_offset(skb) - osize;
+ refcount_add(delta, &sk->sk_wmem_alloc);
+ skb->truesize += delta;
+ }
+ return skb;
+
+fail:
+ kfree_skb(skb);
+ return NULL;
+}
+EXPORT_SYMBOL(skb_expand_head);
+
+/**
+ * skb_copy_expand - copy and expand sk_buff
+ * @skb: buffer to copy
+ * @newheadroom: new free bytes at head
+ * @newtailroom: new free bytes at tail
+ * @gfp_mask: allocation priority
+ *
+ * Make a copy of both an &sk_buff and its data and while doing so
+ * allocate additional space.
+ *
+ * This is used when the caller wishes to modify the data and needs a
+ * private copy of the data to alter as well as more space for new fields.
+ * Returns %NULL on failure or the pointer to the buffer
+ * on success. The returned buffer has a reference count of 1.
+ *
+ * You must pass %GFP_ATOMIC as the allocation priority if this function
+ * is called from an interrupt.
+ */
+struct sk_buff *skb_copy_expand(const struct sk_buff *skb,
+ int newheadroom, int newtailroom,
+ gfp_t gfp_mask)
+{
+ /*
+ * Allocate the copy buffer
+ */
+ struct sk_buff *n = __alloc_skb(newheadroom + skb->len + newtailroom,
+ gfp_mask, skb_alloc_rx_flag(skb),
+ NUMA_NO_NODE);
+ int oldheadroom = skb_headroom(skb);
+ int head_copy_len, head_copy_off;
+
+ if (!n)
+ return NULL;
+
+ skb_reserve(n, newheadroom);
+
+ /* Set the tail pointer and length */
+ skb_put(n, skb->len);
+
+ head_copy_len = oldheadroom;
+ head_copy_off = 0;
+ if (newheadroom <= head_copy_len)
+ head_copy_len = newheadroom;
+ else
+ head_copy_off = newheadroom - head_copy_len;
+
+ /* Copy the linear header and data. */
+ BUG_ON(skb_copy_bits(skb, -head_copy_len, n->head + head_copy_off,
+ skb->len + head_copy_len));
+
+ skb_copy_header(n, skb);
+
+ skb_headers_offset_update(n, newheadroom - oldheadroom);
+
+ return n;
+}
+EXPORT_SYMBOL(skb_copy_expand);
+
+/**
+ * __skb_pad - zero pad the tail of an skb
+ * @skb: buffer to pad
+ * @pad: space to pad
+ * @free_on_error: free buffer on error
+ *
+ * Ensure that a buffer is followed by a padding area that is zero
+ * filled. Used by network drivers which may DMA or transfer data
+ * beyond the buffer end onto the wire.
+ *
+ * May return error in out of memory cases. The skb is freed on error
+ * if @free_on_error is true.
+ */
+
+int __skb_pad(struct sk_buff *skb, int pad, bool free_on_error)
+{
+ int err;
+ int ntail;
+
+ /* If the skbuff is non linear tailroom is always zero.. */
+ if (!skb_cloned(skb) && skb_tailroom(skb) >= pad) {
+ memset(skb->data+skb->len, 0, pad);
+ return 0;
+ }
+
+ ntail = skb->data_len + pad - (skb->end - skb->tail);
+ if (likely(skb_cloned(skb) || ntail > 0)) {
+ err = pskb_expand_head(skb, 0, ntail, GFP_ATOMIC);
+ if (unlikely(err))
+ goto free_skb;
+ }
+
+ /* FIXME: The use of this function with non-linear skb's really needs
+ * to be audited.
+ */
+ err = skb_linearize(skb);
+ if (unlikely(err))
+ goto free_skb;
+
+ memset(skb->data + skb->len, 0, pad);
+ return 0;
+
+free_skb:
+ if (free_on_error)
+ kfree_skb(skb);
+ return err;
+}
+EXPORT_SYMBOL(__skb_pad);
+
+/**
+ * pskb_put - add data to the tail of a potentially fragmented buffer
+ * @skb: start of the buffer to use
+ * @tail: tail fragment of the buffer to use
+ * @len: amount of data to add
+ *
+ * This function extends the used data area of the potentially
+ * fragmented buffer. @tail must be the last fragment of @skb -- or
+ * @skb itself. If this would exceed the total buffer size the kernel
+ * will panic. A pointer to the first byte of the extra data is
+ * returned.
+ */
+
+void *pskb_put(struct sk_buff *skb, struct sk_buff *tail, int len)
+{
+ if (tail != skb) {
+ skb->data_len += len;
+ skb->len += len;
+ }
+ return skb_put(tail, len);
+}
+EXPORT_SYMBOL_GPL(pskb_put);
+
+/**
+ * skb_put - add data to a buffer
+ * @skb: buffer to use
+ * @len: amount of data to add
+ *
+ * This function extends the used data area of the buffer. If this would
+ * exceed the total buffer size the kernel will panic. A pointer to the
+ * first byte of the extra data is returned.
+ */
+void *skb_put(struct sk_buff *skb, unsigned int len)
+{
+ void *tmp = skb_tail_pointer(skb);
+ SKB_LINEAR_ASSERT(skb);
+ skb->tail += len;
+ skb->len += len;
+ if (unlikely(skb->tail > skb->end))
+ skb_over_panic(skb, len, __builtin_return_address(0));
+ return tmp;
+}
+EXPORT_SYMBOL(skb_put);
+
+/**
+ * skb_push - add data to the start of a buffer
+ * @skb: buffer to use
+ * @len: amount of data to add
+ *
+ * This function extends the used data area of the buffer at the buffer
+ * start. If this would exceed the total buffer headroom the kernel will
+ * panic. A pointer to the first byte of the extra data is returned.
+ */
+void *skb_push(struct sk_buff *skb, unsigned int len)
+{
+ skb->data -= len;
+ skb->len += len;
+ if (unlikely(skb->data < skb->head))
+ skb_under_panic(skb, len, __builtin_return_address(0));
+ return skb->data;
+}
+EXPORT_SYMBOL(skb_push);
+
+/**
+ * skb_pull - remove data from the start of a buffer
+ * @skb: buffer to use
+ * @len: amount of data to remove
+ *
+ * This function removes data from the start of a buffer, returning
+ * the memory to the headroom. A pointer to the next data in the buffer
+ * is returned. Once the data has been pulled future pushes will overwrite
+ * the old data.
+ */
+void *skb_pull(struct sk_buff *skb, unsigned int len)
+{
+ return skb_pull_inline(skb, len);
+}
+EXPORT_SYMBOL(skb_pull);
+
+/**
+ * skb_trim - remove end from a buffer
+ * @skb: buffer to alter
+ * @len: new length
+ *
+ * Cut the length of a buffer down by removing data from the tail. If
+ * the buffer is already under the length specified it is not modified.
+ * The skb must be linear.
+ */
+void skb_trim(struct sk_buff *skb, unsigned int len)
+{
+ if (skb->len > len)
+ __skb_trim(skb, len);
+}
+EXPORT_SYMBOL(skb_trim);
+
+/* Trims skb to length len. It can change skb pointers.
+ */
+
+int ___pskb_trim(struct sk_buff *skb, unsigned int len)
+{
+ struct sk_buff **fragp;
+ struct sk_buff *frag;
+ int offset = skb_headlen(skb);
+ int nfrags = skb_shinfo(skb)->nr_frags;
+ int i;
+ int err;
+
+ if (skb_cloned(skb) &&
+ unlikely((err = pskb_expand_head(skb, 0, 0, GFP_ATOMIC))))
+ return err;
+
+ i = 0;
+ if (offset >= len)
+ goto drop_pages;
+
+ for (; i < nfrags; i++) {
+ int end = offset + skb_frag_size(&skb_shinfo(skb)->frags[i]);
+
+ if (end < len) {
+ offset = end;
+ continue;
+ }
+
+ skb_frag_size_set(&skb_shinfo(skb)->frags[i++], len - offset);
+
+drop_pages:
+ skb_shinfo(skb)->nr_frags = i;
+
+ for (; i < nfrags; i++)
+ skb_frag_unref(skb, i);
+
+ if (skb_has_frag_list(skb))
+ skb_drop_fraglist(skb);
+ goto done;
+ }
+
+ for (fragp = &skb_shinfo(skb)->frag_list; (frag = *fragp);
+ fragp = &frag->next) {
+ int end = offset + frag->len;
+
+ if (skb_shared(frag)) {
+ struct sk_buff *nfrag;
+
+ nfrag = skb_clone(frag, GFP_ATOMIC);
+ if (unlikely(!nfrag))
+ return -ENOMEM;
+
+ nfrag->next = frag->next;
+ consume_skb(frag);
+ frag = nfrag;
+ *fragp = frag;
+ }
+
+ if (end < len) {
+ offset = end;
+ continue;
+ }
+
+ if (end > len &&
+ unlikely((err = pskb_trim(frag, len - offset))))
+ return err;
+
+ if (frag->next)
+ skb_drop_list(&frag->next);
+ break;
+ }
+
+done:
+ if (len > skb_headlen(skb)) {
+ skb->data_len -= skb->len - len;
+ skb->len = len;
+ } else {
+ skb->len = len;
+ skb->data_len = 0;
+ skb_set_tail_pointer(skb, len);
+ }
+
+ if (!skb->sk || skb->destructor == sock_edemux)
+ skb_condense(skb);
+ return 0;
+}
+EXPORT_SYMBOL(___pskb_trim);
+
+/* Note : use pskb_trim_rcsum() instead of calling this directly
+ */
+int pskb_trim_rcsum_slow(struct sk_buff *skb, unsigned int len)
+{
+ if (skb->ip_summed == CHECKSUM_COMPLETE) {
+ int delta = skb->len - len;
+
+ skb->csum = csum_block_sub(skb->csum,
+ skb_checksum(skb, len, delta, 0),
+ len);
+ } else if (skb->ip_summed == CHECKSUM_PARTIAL) {
+ int hdlen = (len > skb_headlen(skb)) ? skb_headlen(skb) : len;
+ int offset = skb_checksum_start_offset(skb) + skb->csum_offset;
+
+ if (offset + sizeof(__sum16) > hdlen)
+ return -EINVAL;
+ }
+ return __pskb_trim(skb, len);
+}
+EXPORT_SYMBOL(pskb_trim_rcsum_slow);
+
+/**
+ * __pskb_pull_tail - advance tail of skb header
+ * @skb: buffer to reallocate
+ * @delta: number of bytes to advance tail
+ *
+ * The function makes a sense only on a fragmented &sk_buff,
+ * it expands header moving its tail forward and copying necessary
+ * data from fragmented part.
+ *
+ * &sk_buff MUST have reference count of 1.
+ *
+ * Returns %NULL (and &sk_buff does not change) if pull failed
+ * or value of new tail of skb in the case of success.
+ *
+ * All the pointers pointing into skb header may change and must be
+ * reloaded after call to this function.
+ */
+
+/* Moves tail of skb head forward, copying data from fragmented part,
+ * when it is necessary.
+ * 1. It may fail due to malloc failure.
+ * 2. It may change skb pointers.
+ *
+ * It is pretty complicated. Luckily, it is called only in exceptional cases.
+ */
+void *__pskb_pull_tail(struct sk_buff *skb, int delta)
+{
+ /* If skb has not enough free space at tail, get new one
+ * plus 128 bytes for future expansions. If we have enough
+ * room at tail, reallocate without expansion only if skb is cloned.
+ */
+ int i, k, eat = (skb->tail + delta) - skb->end;
+
+ if (eat > 0 || skb_cloned(skb)) {
+ if (pskb_expand_head(skb, 0, eat > 0 ? eat + 128 : 0,
+ GFP_ATOMIC))
+ return NULL;
+ }
+
+ BUG_ON(skb_copy_bits(skb, skb_headlen(skb),
+ skb_tail_pointer(skb), delta));
+
+ /* Optimization: no fragments, no reasons to preestimate
+ * size of pulled pages. Superb.
+ */
+ if (!skb_has_frag_list(skb))
+ goto pull_pages;
+
+ /* Estimate size of pulled pages. */
+ eat = delta;
+ for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
+ int size = skb_frag_size(&skb_shinfo(skb)->frags[i]);
+
+ if (size >= eat)
+ goto pull_pages;
+ eat -= size;
+ }
+
+ /* If we need update frag list, we are in troubles.
+ * Certainly, it is possible to add an offset to skb data,
+ * but taking into account that pulling is expected to
+ * be very rare operation, it is worth to fight against
+ * further bloating skb head and crucify ourselves here instead.
+ * Pure masohism, indeed. 8)8)
+ */
+ if (eat) {
+ struct sk_buff *list = skb_shinfo(skb)->frag_list;
+ struct sk_buff *clone = NULL;
+ struct sk_buff *insp = NULL;
+
+ do {
+ if (list->len <= eat) {
+ /* Eaten as whole. */
+ eat -= list->len;
+ list = list->next;
+ insp = list;
+ } else {
+ /* Eaten partially. */
+ if (skb_is_gso(skb) && !list->head_frag &&
+ skb_headlen(list))
+ skb_shinfo(skb)->gso_type |= SKB_GSO_DODGY;
+
+ if (skb_shared(list)) {
+ /* Sucks! We need to fork list. :-( */
+ clone = skb_clone(list, GFP_ATOMIC);
+ if (!clone)
+ return NULL;
+ insp = list->next;
+ list = clone;
+ } else {
+ /* This may be pulled without
+ * problems. */
+ insp = list;
+ }
+ if (!pskb_pull(list, eat)) {
+ kfree_skb(clone);
+ return NULL;
+ }
+ break;
+ }
+ } while (eat);
+
+ /* Free pulled out fragments. */
+ while ((list = skb_shinfo(skb)->frag_list) != insp) {
+ skb_shinfo(skb)->frag_list = list->next;
+ consume_skb(list);
+ }
+ /* And insert new clone at head. */
+ if (clone) {
+ clone->next = list;
+ skb_shinfo(skb)->frag_list = clone;
+ }
+ }
+ /* Success! Now we may commit changes to skb data. */
+
+pull_pages:
+ eat = delta;
+ k = 0;
+ for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
+ int size = skb_frag_size(&skb_shinfo(skb)->frags[i]);
+
+ if (size <= eat) {
+ skb_frag_unref(skb, i);
+ eat -= size;
+ } else {
+ skb_frag_t *frag = &skb_shinfo(skb)->frags[k];
+
+ *frag = skb_shinfo(skb)->frags[i];
+ if (eat) {
+ skb_frag_off_add(frag, eat);
+ skb_frag_size_sub(frag, eat);
+ if (!i)
+ goto end;
+ eat = 0;
+ }
+ k++;
+ }
+ }
+ skb_shinfo(skb)->nr_frags = k;
+
+end:
+ skb->tail += delta;
+ skb->data_len -= delta;
+
+ if (!skb->data_len)
+ skb_zcopy_clear(skb, false);
+
+ return skb_tail_pointer(skb);
+}
+EXPORT_SYMBOL(__pskb_pull_tail);
+
+/**
+ * skb_copy_bits - copy bits from skb to kernel buffer
+ * @skb: source skb
+ * @offset: offset in source
+ * @to: destination buffer
+ * @len: number of bytes to copy
+ *
+ * Copy the specified number of bytes from the source skb to the
+ * destination buffer.
+ *
+ * CAUTION ! :
+ * If its prototype is ever changed,
+ * check arch/{*}/net/{*}.S files,
+ * since it is called from BPF assembly code.
+ */
+int skb_copy_bits(const struct sk_buff *skb, int offset, void *to, int len)
+{
+ int start = skb_headlen(skb);
+ struct sk_buff *frag_iter;
+ int i, copy;
+
+ if (offset > (int)skb->len - len)
+ goto fault;
+
+ /* Copy header. */
+ if ((copy = start - offset) > 0) {
+ if (copy > len)
+ copy = len;
+ skb_copy_from_linear_data_offset(skb, offset, to, copy);
+ if ((len -= copy) == 0)
+ return 0;
+ offset += copy;
+ to += copy;
+ }
+
+ for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
+ int end;
+ skb_frag_t *f = &skb_shinfo(skb)->frags[i];
+
+ WARN_ON(start > offset + len);
+
+ end = start + skb_frag_size(f);
+ if ((copy = end - offset) > 0) {
+ u32 p_off, p_len, copied;
+ struct page *p;
+ u8 *vaddr;
+
+ if (copy > len)
+ copy = len;
+
+ skb_frag_foreach_page(f,
+ skb_frag_off(f) + offset - start,
+ copy, p, p_off, p_len, copied) {
+ vaddr = kmap_atomic(p);
+ memcpy(to + copied, vaddr + p_off, p_len);
+ kunmap_atomic(vaddr);
+ }
+
+ if ((len -= copy) == 0)
+ return 0;
+ offset += copy;
+ to += copy;
+ }
+ start = end;
+ }
+
+ skb_walk_frags(skb, frag_iter) {
+ int end;
+
+ WARN_ON(start > offset + len);
+
+ end = start + frag_iter->len;
+ if ((copy = end - offset) > 0) {
+ if (copy > len)
+ copy = len;
+ if (skb_copy_bits(frag_iter, offset - start, to, copy))
+ goto fault;
+ if ((len -= copy) == 0)
+ return 0;
+ offset += copy;
+ to += copy;
+ }
+ start = end;
+ }
+
+ if (!len)
+ return 0;
+
+fault:
+ return -EFAULT;
+}
+EXPORT_SYMBOL(skb_copy_bits);
+
+/*
+ * Callback from splice_to_pipe(), if we need to release some pages
+ * at the end of the spd in case we error'ed out in filling the pipe.
+ */
+static void sock_spd_release(struct splice_pipe_desc *spd, unsigned int i)
+{
+ put_page(spd->pages[i]);
+}
+
+static struct page *linear_to_page(struct page *page, unsigned int *len,
+ unsigned int *offset,
+ struct sock *sk)
+{
+ struct page_frag *pfrag = sk_page_frag(sk);
+
+ if (!sk_page_frag_refill(sk, pfrag))
+ return NULL;
+
+ *len = min_t(unsigned int, *len, pfrag->size - pfrag->offset);
+
+ memcpy(page_address(pfrag->page) + pfrag->offset,
+ page_address(page) + *offset, *len);
+ *offset = pfrag->offset;
+ pfrag->offset += *len;
+
+ return pfrag->page;
+}
+
+static bool spd_can_coalesce(const struct splice_pipe_desc *spd,
+ struct page *page,
+ unsigned int offset)
+{
+ return spd->nr_pages &&
+ spd->pages[spd->nr_pages - 1] == page &&
+ (spd->partial[spd->nr_pages - 1].offset +
+ spd->partial[spd->nr_pages - 1].len == offset);
+}
+
+/*
+ * Fill page/offset/length into spd, if it can hold more pages.
+ */
+static bool spd_fill_page(struct splice_pipe_desc *spd,
+ struct pipe_inode_info *pipe, struct page *page,
+ unsigned int *len, unsigned int offset,
+ bool linear,
+ struct sock *sk)
+{
+ if (unlikely(spd->nr_pages == MAX_SKB_FRAGS))
+ return true;
+
+ if (linear) {
+ page = linear_to_page(page, len, &offset, sk);
+ if (!page)
+ return true;
+ }
+ if (spd_can_coalesce(spd, page, offset)) {
+ spd->partial[spd->nr_pages - 1].len += *len;
+ return false;
+ }
+ get_page(page);
+ spd->pages[spd->nr_pages] = page;
+ spd->partial[spd->nr_pages].len = *len;
+ spd->partial[spd->nr_pages].offset = offset;
+ spd->nr_pages++;
+
+ return false;
+}
+
+static bool __splice_segment(struct page *page, unsigned int poff,
+ unsigned int plen, unsigned int *off,
+ unsigned int *len,
+ struct splice_pipe_desc *spd, bool linear,
+ struct sock *sk,
+ struct pipe_inode_info *pipe)
+{
+ if (!*len)
+ return true;
+
+ /* skip this segment if already processed */
+ if (*off >= plen) {
+ *off -= plen;
+ return false;
+ }
+
+ /* ignore any bits we already processed */
+ poff += *off;
+ plen -= *off;
+ *off = 0;
+
+ do {
+ unsigned int flen = min(*len, plen);
+
+ if (spd_fill_page(spd, pipe, page, &flen, poff,
+ linear, sk))
+ return true;
+ poff += flen;
+ plen -= flen;
+ *len -= flen;
+ } while (*len && plen);
+
+ return false;
+}
+
+/*
+ * Map linear and fragment data from the skb to spd. It reports true if the
+ * pipe is full or if we already spliced the requested length.
+ */
+static bool __skb_splice_bits(struct sk_buff *skb, struct pipe_inode_info *pipe,
+ unsigned int *offset, unsigned int *len,
+ struct splice_pipe_desc *spd, struct sock *sk)
+{
+ int seg;
+ struct sk_buff *iter;
+
+ /* map the linear part :
+ * If skb->head_frag is set, this 'linear' part is backed by a
+ * fragment, and if the head is not shared with any clones then
+ * we can avoid a copy since we own the head portion of this page.
+ */
+ if (__splice_segment(virt_to_page(skb->data),
+ (unsigned long) skb->data & (PAGE_SIZE - 1),
+ skb_headlen(skb),
+ offset, len, spd,
+ skb_head_is_locked(skb),
+ sk, pipe))
+ return true;
+
+ /*
+ * then map the fragments
+ */
+ for (seg = 0; seg < skb_shinfo(skb)->nr_frags; seg++) {
+ const skb_frag_t *f = &skb_shinfo(skb)->frags[seg];
+
+ if (__splice_segment(skb_frag_page(f),
+ skb_frag_off(f), skb_frag_size(f),
+ offset, len, spd, false, sk, pipe))
+ return true;
+ }
+
+ skb_walk_frags(skb, iter) {
+ if (*offset >= iter->len) {
+ *offset -= iter->len;
+ continue;
+ }
+ /* __skb_splice_bits() only fails if the output has no room
+ * left, so no point in going over the frag_list for the error
+ * case.
+ */
+ if (__skb_splice_bits(iter, pipe, offset, len, spd, sk))
+ return true;
+ }
+
+ return false;
+}
+
+/*
+ * Map data from the skb to a pipe. Should handle both the linear part,
+ * the fragments, and the frag list.
+ */
+int skb_splice_bits(struct sk_buff *skb, struct sock *sk, unsigned int offset,
+ struct pipe_inode_info *pipe, unsigned int tlen,
+ unsigned int flags)
+{
+ struct partial_page partial[MAX_SKB_FRAGS];
+ struct page *pages[MAX_SKB_FRAGS];
+ struct splice_pipe_desc spd = {
+ .pages = pages,
+ .partial = partial,
+ .nr_pages_max = MAX_SKB_FRAGS,
+ .ops = &nosteal_pipe_buf_ops,
+ .spd_release = sock_spd_release,
+ };
+ int ret = 0;
+
+ __skb_splice_bits(skb, pipe, &offset, &tlen, &spd, sk);
+
+ if (spd.nr_pages)
+ ret = splice_to_pipe(pipe, &spd);
+
+ return ret;
+}
+EXPORT_SYMBOL_GPL(skb_splice_bits);
+
+/* Send skb data on a socket. Socket must be locked. */
+int skb_send_sock_locked(struct sock *sk, struct sk_buff *skb, int offset,
+ int len)
+{
+ unsigned int orig_len = len;
+ struct sk_buff *head = skb;
+ unsigned short fragidx;
+ int slen, ret;
+
+do_frag_list:
+
+ /* Deal with head data */
+ while (offset < skb_headlen(skb) && len) {
+ struct kvec kv;
+ struct msghdr msg;
+
+ slen = min_t(int, len, skb_headlen(skb) - offset);
+ kv.iov_base = skb->data + offset;
+ kv.iov_len = slen;
+ memset(&msg, 0, sizeof(msg));
+ msg.msg_flags = MSG_DONTWAIT;
+
+ ret = kernel_sendmsg_locked(sk, &msg, &kv, 1, slen);
+ if (ret <= 0)
+ goto error;
+
+ offset += ret;
+ len -= ret;
+ }
+
+ /* All the data was skb head? */
+ if (!len)
+ goto out;
+
+ /* Make offset relative to start of frags */
+ offset -= skb_headlen(skb);
+
+ /* Find where we are in frag list */
+ for (fragidx = 0; fragidx < skb_shinfo(skb)->nr_frags; fragidx++) {
+ skb_frag_t *frag = &skb_shinfo(skb)->frags[fragidx];
+
+ if (offset < skb_frag_size(frag))
+ break;
+
+ offset -= skb_frag_size(frag);
+ }
+
+ for (; len && fragidx < skb_shinfo(skb)->nr_frags; fragidx++) {
+ skb_frag_t *frag = &skb_shinfo(skb)->frags[fragidx];
+
+ slen = min_t(size_t, len, skb_frag_size(frag) - offset);
+
+ while (slen) {
+ ret = kernel_sendpage_locked(sk, skb_frag_page(frag),
+ skb_frag_off(frag) + offset,
+ slen, MSG_DONTWAIT);
+ if (ret <= 0)
+ goto error;
+
+ len -= ret;
+ offset += ret;
+ slen -= ret;
+ }
+
+ offset = 0;
+ }
+
+ if (len) {
+ /* Process any frag lists */
+
+ if (skb == head) {
+ if (skb_has_frag_list(skb)) {
+ skb = skb_shinfo(skb)->frag_list;
+ goto do_frag_list;
+ }
+ } else if (skb->next) {
+ skb = skb->next;
+ goto do_frag_list;
+ }
+ }
+
+out:
+ return orig_len - len;
+
+error:
+ return orig_len == len ? ret : orig_len - len;
+}
+EXPORT_SYMBOL_GPL(skb_send_sock_locked);
+
+/**
+ * skb_store_bits - store bits from kernel buffer to skb
+ * @skb: destination buffer
+ * @offset: offset in destination
+ * @from: source buffer
+ * @len: number of bytes to copy
+ *
+ * Copy the specified number of bytes from the source buffer to the
+ * destination skb. This function handles all the messy bits of
+ * traversing fragment lists and such.
+ */
+
+int skb_store_bits(struct sk_buff *skb, int offset, const void *from, int len)
+{
+ int start = skb_headlen(skb);
+ struct sk_buff *frag_iter;
+ int i, copy;
+
+ if (offset > (int)skb->len - len)
+ goto fault;
+
+ if ((copy = start - offset) > 0) {
+ if (copy > len)
+ copy = len;
+ skb_copy_to_linear_data_offset(skb, offset, from, copy);
+ if ((len -= copy) == 0)
+ return 0;
+ offset += copy;
+ from += copy;
+ }
+
+ for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
+ skb_frag_t *frag = &skb_shinfo(skb)->frags[i];
+ int end;
+
+ WARN_ON(start > offset + len);
+
+ end = start + skb_frag_size(frag);
+ if ((copy = end - offset) > 0) {
+ u32 p_off, p_len, copied;
+ struct page *p;
+ u8 *vaddr;
+
+ if (copy > len)
+ copy = len;
+
+ skb_frag_foreach_page(frag,
+ skb_frag_off(frag) + offset - start,
+ copy, p, p_off, p_len, copied) {
+ vaddr = kmap_atomic(p);
+ memcpy(vaddr + p_off, from + copied, p_len);
+ kunmap_atomic(vaddr);
+ }
+
+ if ((len -= copy) == 0)
+ return 0;
+ offset += copy;
+ from += copy;
+ }
+ start = end;
+ }
+
+ skb_walk_frags(skb, frag_iter) {
+ int end;
+
+ WARN_ON(start > offset + len);
+
+ end = start + frag_iter->len;
+ if ((copy = end - offset) > 0) {
+ if (copy > len)
+ copy = len;
+ if (skb_store_bits(frag_iter, offset - start,
+ from, copy))
+ goto fault;
+ if ((len -= copy) == 0)
+ return 0;
+ offset += copy;
+ from += copy;
+ }
+ start = end;
+ }
+ if (!len)
+ return 0;
+
+fault:
+ return -EFAULT;
+}
+EXPORT_SYMBOL(skb_store_bits);
+
+/* Checksum skb data. */
+__wsum __skb_checksum(const struct sk_buff *skb, int offset, int len,
+ __wsum csum, const struct skb_checksum_ops *ops)
+{
+ int start = skb_headlen(skb);
+ int i, copy = start - offset;
+ struct sk_buff *frag_iter;
+ int pos = 0;
+
+ /* Checksum header. */
+ if (copy > 0) {
+ if (copy > len)
+ copy = len;
+ csum = INDIRECT_CALL_1(ops->update, csum_partial_ext,
+ skb->data + offset, copy, csum);
+ if ((len -= copy) == 0)
+ return csum;
+ offset += copy;
+ pos = copy;
+ }
+
+ for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
+ int end;
+ skb_frag_t *frag = &skb_shinfo(skb)->frags[i];
+
+ WARN_ON(start > offset + len);
+
+ end = start + skb_frag_size(frag);
+ if ((copy = end - offset) > 0) {
+ u32 p_off, p_len, copied;
+ struct page *p;
+ __wsum csum2;
+ u8 *vaddr;
+
+ if (copy > len)
+ copy = len;
+
+ skb_frag_foreach_page(frag,
+ skb_frag_off(frag) + offset - start,
+ copy, p, p_off, p_len, copied) {
+ vaddr = kmap_atomic(p);
+ csum2 = INDIRECT_CALL_1(ops->update,
+ csum_partial_ext,
+ vaddr + p_off, p_len, 0);
+ kunmap_atomic(vaddr);
+ csum = INDIRECT_CALL_1(ops->combine,
+ csum_block_add_ext, csum,
+ csum2, pos, p_len);
+ pos += p_len;
+ }
+
+ if (!(len -= copy))
+ return csum;
+ offset += copy;
+ }
+ start = end;
+ }
+
+ skb_walk_frags(skb, frag_iter) {
+ int end;
+
+ WARN_ON(start > offset + len);
+
+ end = start + frag_iter->len;
+ if ((copy = end - offset) > 0) {
+ __wsum csum2;
+ if (copy > len)
+ copy = len;
+ csum2 = __skb_checksum(frag_iter, offset - start,
+ copy, 0, ops);
+ csum = INDIRECT_CALL_1(ops->combine, csum_block_add_ext,
+ csum, csum2, pos, copy);
+ if ((len -= copy) == 0)
+ return csum;
+ offset += copy;
+ pos += copy;
+ }
+ start = end;
+ }
+ BUG_ON(len);
+
+ return csum;
+}
+EXPORT_SYMBOL(__skb_checksum);
+
+__wsum skb_checksum(const struct sk_buff *skb, int offset,
+ int len, __wsum csum)
+{
+ const struct skb_checksum_ops ops = {
+ .update = csum_partial_ext,
+ .combine = csum_block_add_ext,
+ };
+
+ return __skb_checksum(skb, offset, len, csum, &ops);
+}
+EXPORT_SYMBOL(skb_checksum);
+
+/* Both of above in one bottle. */
+
+__wsum skb_copy_and_csum_bits(const struct sk_buff *skb, int offset,
+ u8 *to, int len, __wsum csum)
+{
+ int start = skb_headlen(skb);
+ int i, copy = start - offset;
+ struct sk_buff *frag_iter;
+ int pos = 0;
+
+ /* Copy header. */
+ if (copy > 0) {
+ if (copy > len)
+ copy = len;
+ csum = csum_partial_copy_nocheck(skb->data + offset, to,
+ copy, csum);
+ if ((len -= copy) == 0)
+ return csum;
+ offset += copy;
+ to += copy;
+ pos = copy;
+ }
+
+ for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
+ int end;
+
+ WARN_ON(start > offset + len);
+
+ end = start + skb_frag_size(&skb_shinfo(skb)->frags[i]);
+ if ((copy = end - offset) > 0) {
+ skb_frag_t *frag = &skb_shinfo(skb)->frags[i];
+ u32 p_off, p_len, copied;
+ struct page *p;
+ __wsum csum2;
+ u8 *vaddr;
+
+ if (copy > len)
+ copy = len;
+
+ skb_frag_foreach_page(frag,
+ skb_frag_off(frag) + offset - start,
+ copy, p, p_off, p_len, copied) {
+ vaddr = kmap_atomic(p);
+ csum2 = csum_partial_copy_nocheck(vaddr + p_off,
+ to + copied,
+ p_len, 0);
+ kunmap_atomic(vaddr);
+ csum = csum_block_add(csum, csum2, pos);
+ pos += p_len;
+ }
+
+ if (!(len -= copy))
+ return csum;
+ offset += copy;
+ to += copy;
+ }
+ start = end;
+ }
+
+ skb_walk_frags(skb, frag_iter) {
+ __wsum csum2;
+ int end;
+
+ WARN_ON(start > offset + len);
+
+ end = start + frag_iter->len;
+ if ((copy = end - offset) > 0) {
+ if (copy > len)
+ copy = len;
+ csum2 = skb_copy_and_csum_bits(frag_iter,
+ offset - start,
+ to, copy, 0);
+ csum = csum_block_add(csum, csum2, pos);
+ if ((len -= copy) == 0)
+ return csum;
+ offset += copy;
+ to += copy;
+ pos += copy;
+ }
+ start = end;
+ }
+ BUG_ON(len);
+ return csum;
+}
+EXPORT_SYMBOL(skb_copy_and_csum_bits);
+
+__sum16 __skb_checksum_complete_head(struct sk_buff *skb, int len)
+{
+ __sum16 sum;
+
+ sum = csum_fold(skb_checksum(skb, 0, len, skb->csum));
+ /* See comments in __skb_checksum_complete(). */
+ if (likely(!sum)) {
+ if (unlikely(skb->ip_summed == CHECKSUM_COMPLETE) &&
+ !skb->csum_complete_sw)
+ netdev_rx_csum_fault(skb->dev, skb);
+ }
+ if (!skb_shared(skb))
+ skb->csum_valid = !sum;
+ return sum;
+}
+EXPORT_SYMBOL(__skb_checksum_complete_head);
+
+/* This function assumes skb->csum already holds pseudo header's checksum,
+ * which has been changed from the hardware checksum, for example, by
+ * __skb_checksum_validate_complete(). And, the original skb->csum must
+ * have been validated unsuccessfully for CHECKSUM_COMPLETE case.
+ *
+ * It returns non-zero if the recomputed checksum is still invalid, otherwise
+ * zero. The new checksum is stored back into skb->csum unless the skb is
+ * shared.
+ */
+__sum16 __skb_checksum_complete(struct sk_buff *skb)
+{
+ __wsum csum;
+ __sum16 sum;
+
+ csum = skb_checksum(skb, 0, skb->len, 0);
+
+ sum = csum_fold(csum_add(skb->csum, csum));
+ /* This check is inverted, because we already knew the hardware
+ * checksum is invalid before calling this function. So, if the
+ * re-computed checksum is valid instead, then we have a mismatch
+ * between the original skb->csum and skb_checksum(). This means either
+ * the original hardware checksum is incorrect or we screw up skb->csum
+ * when moving skb->data around.
+ */
+ if (likely(!sum)) {
+ if (unlikely(skb->ip_summed == CHECKSUM_COMPLETE) &&
+ !skb->csum_complete_sw)
+ netdev_rx_csum_fault(skb->dev, skb);
+ }
+
+ if (!skb_shared(skb)) {
+ /* Save full packet checksum */
+ skb->csum = csum;
+ skb->ip_summed = CHECKSUM_COMPLETE;
+ skb->csum_complete_sw = 1;
+ skb->csum_valid = !sum;
+ }
+
+ return sum;
+}
+EXPORT_SYMBOL(__skb_checksum_complete);
+
+static __wsum warn_crc32c_csum_update(const void *buff, int len, __wsum sum)
+{
+ net_warn_ratelimited(
+ "%s: attempt to compute crc32c without libcrc32c.ko\n",
+ __func__);
+ return 0;
+}
+
+static __wsum warn_crc32c_csum_combine(__wsum csum, __wsum csum2,
+ int offset, int len)
+{
+ net_warn_ratelimited(
+ "%s: attempt to compute crc32c without libcrc32c.ko\n",
+ __func__);
+ return 0;
+}
+
+static const struct skb_checksum_ops default_crc32c_ops = {
+ .update = warn_crc32c_csum_update,
+ .combine = warn_crc32c_csum_combine,
+};
+
+const struct skb_checksum_ops *crc32c_csum_stub __read_mostly =
+ &default_crc32c_ops;
+EXPORT_SYMBOL(crc32c_csum_stub);
+
+ /**
+ * skb_zerocopy_headlen - Calculate headroom needed for skb_zerocopy()
+ * @from: source buffer
+ *
+ * Calculates the amount of linear headroom needed in the 'to' skb passed
+ * into skb_zerocopy().
+ */
+unsigned int
+skb_zerocopy_headlen(const struct sk_buff *from)
+{
+ unsigned int hlen = 0;
+
+ if (!from->head_frag ||
+ skb_headlen(from) < L1_CACHE_BYTES ||
+ skb_shinfo(from)->nr_frags >= MAX_SKB_FRAGS) {
+ hlen = skb_headlen(from);
+ if (!hlen)
+ hlen = from->len;
+ }
+
+ if (skb_has_frag_list(from))
+ hlen = from->len;
+
+ return hlen;
+}
+EXPORT_SYMBOL_GPL(skb_zerocopy_headlen);
+
+/**
+ * skb_zerocopy - Zero copy skb to skb
+ * @to: destination buffer
+ * @from: source buffer
+ * @len: number of bytes to copy from source buffer
+ * @hlen: size of linear headroom in destination buffer
+ *
+ * Copies up to `len` bytes from `from` to `to` by creating references
+ * to the frags in the source buffer.
+ *
+ * The `hlen` as calculated by skb_zerocopy_headlen() specifies the
+ * headroom in the `to` buffer.
+ *
+ * Return value:
+ * 0: everything is OK
+ * -ENOMEM: couldn't orphan frags of @from due to lack of memory
+ * -EFAULT: skb_copy_bits() found some problem with skb geometry
+ */
+int
+skb_zerocopy(struct sk_buff *to, struct sk_buff *from, int len, int hlen)
+{
+ int i, j = 0;
+ int plen = 0; /* length of skb->head fragment */
+ int ret;
+ struct page *page;
+ unsigned int offset;
+
+ BUG_ON(!from->head_frag && !hlen);
+
+ /* dont bother with small payloads */
+ if (len <= skb_tailroom(to))
+ return skb_copy_bits(from, 0, skb_put(to, len), len);
+
+ if (hlen) {
+ ret = skb_copy_bits(from, 0, skb_put(to, hlen), hlen);
+ if (unlikely(ret))
+ return ret;
+ len -= hlen;
+ } else {
+ plen = min_t(int, skb_headlen(from), len);
+ if (plen) {
+ page = virt_to_head_page(from->head);
+ offset = from->data - (unsigned char *)page_address(page);
+ __skb_fill_page_desc(to, 0, page, offset, plen);
+ get_page(page);
+ j = 1;
+ len -= plen;
+ }
+ }
+
+ to->truesize += len + plen;
+ to->len += len + plen;
+ to->data_len += len + plen;
+
+ if (unlikely(skb_orphan_frags(from, GFP_ATOMIC))) {
+ skb_tx_error(from);
+ return -ENOMEM;
+ }
+ skb_zerocopy_clone(to, from, GFP_ATOMIC);
+
+ for (i = 0; i < skb_shinfo(from)->nr_frags; i++) {
+ int size;
+
+ if (!len)
+ break;
+ skb_shinfo(to)->frags[j] = skb_shinfo(from)->frags[i];
+ size = min_t(int, skb_frag_size(&skb_shinfo(to)->frags[j]),
+ len);
+ skb_frag_size_set(&skb_shinfo(to)->frags[j], size);
+ len -= size;
+ skb_frag_ref(to, j);
+ j++;
+ }
+ skb_shinfo(to)->nr_frags = j;
+
+ return 0;
+}
+EXPORT_SYMBOL_GPL(skb_zerocopy);
+
+void skb_copy_and_csum_dev(const struct sk_buff *skb, u8 *to)
+{
+ __wsum csum;
+ long csstart;
+
+ if (skb->ip_summed == CHECKSUM_PARTIAL)
+ csstart = skb_checksum_start_offset(skb);
+ else
+ csstart = skb_headlen(skb);
+
+ BUG_ON(csstart > skb_headlen(skb));
+
+ skb_copy_from_linear_data(skb, to, csstart);
+
+ csum = 0;
+ if (csstart != skb->len)
+ csum = skb_copy_and_csum_bits(skb, csstart, to + csstart,
+ skb->len - csstart, 0);
+
+ if (skb->ip_summed == CHECKSUM_PARTIAL) {
+ long csstuff = csstart + skb->csum_offset;
+
+ *((__sum16 *)(to + csstuff)) = csum_fold(csum);
+ }
+}
+EXPORT_SYMBOL(skb_copy_and_csum_dev);
+
+/**
+ * skb_dequeue - remove from the head of the queue
+ * @list: list to dequeue from
+ *
+ * Remove the head of the list. The list lock is taken so the function
+ * may be used safely with other locking list functions. The head item is
+ * returned or %NULL if the list is empty.
+ */
+
+struct sk_buff *skb_dequeue(struct sk_buff_head *list)
+{
+ unsigned long flags;
+ struct sk_buff *result;
+
+ spin_lock_irqsave(&list->lock, flags);
+ result = __skb_dequeue(list);
+ spin_unlock_irqrestore(&list->lock, flags);
+ return result;
+}
+EXPORT_SYMBOL(skb_dequeue);
+
+/**
+ * skb_dequeue_tail - remove from the tail of the queue
+ * @list: list to dequeue from
+ *
+ * Remove the tail of the list. The list lock is taken so the function
+ * may be used safely with other locking list functions. The tail item is
+ * returned or %NULL if the list is empty.
+ */
+struct sk_buff *skb_dequeue_tail(struct sk_buff_head *list)
+{
+ unsigned long flags;
+ struct sk_buff *result;
+
+ spin_lock_irqsave(&list->lock, flags);
+ result = __skb_dequeue_tail(list);
+ spin_unlock_irqrestore(&list->lock, flags);
+ return result;
+}
+EXPORT_SYMBOL(skb_dequeue_tail);
+
+/**
+ * skb_queue_purge - empty a list
+ * @list: list to empty
+ *
+ * Delete all buffers on an &sk_buff list. Each buffer is removed from
+ * the list and one reference dropped. This function takes the list
+ * lock and is atomic with respect to other list locking functions.
+ */
+void skb_queue_purge(struct sk_buff_head *list)
+{
+ struct sk_buff *skb;
+ while ((skb = skb_dequeue(list)) != NULL)
+ kfree_skb(skb);
+}
+EXPORT_SYMBOL(skb_queue_purge);
+
+/**
+ * skb_rbtree_purge - empty a skb rbtree
+ * @root: root of the rbtree to empty
+ * Return value: the sum of truesizes of all purged skbs.
+ *
+ * Delete all buffers on an &sk_buff rbtree. Each buffer is removed from
+ * the list and one reference dropped. This function does not take
+ * any lock. Synchronization should be handled by the caller (e.g., TCP
+ * out-of-order queue is protected by the socket lock).
+ */
+unsigned int skb_rbtree_purge(struct rb_root *root)
+{
+ struct rb_node *p = rb_first(root);
+ unsigned int sum = 0;
+
+ while (p) {
+ struct sk_buff *skb = rb_entry(p, struct sk_buff, rbnode);
+
+ p = rb_next(p);
+ rb_erase(&skb->rbnode, root);
+ sum += skb->truesize;
+ kfree_skb(skb);
+ }
+ return sum;
+}
+
+/**
+ * skb_queue_head - queue a buffer at the list head
+ * @list: list to use
+ * @newsk: buffer to queue
+ *
+ * Queue a buffer at the start of the list. This function takes the
+ * list lock and can be used safely with other locking &sk_buff functions
+ * safely.
+ *
+ * A buffer cannot be placed on two lists at the same time.
+ */
+void skb_queue_head(struct sk_buff_head *list, struct sk_buff *newsk)
+{
+ unsigned long flags;
+
+ spin_lock_irqsave(&list->lock, flags);
+ __skb_queue_head(list, newsk);
+ spin_unlock_irqrestore(&list->lock, flags);
+}
+EXPORT_SYMBOL(skb_queue_head);
+
+/**
+ * skb_queue_tail - queue a buffer at the list tail
+ * @list: list to use
+ * @newsk: buffer to queue
+ *
+ * Queue a buffer at the tail of the list. This function takes the
+ * list lock and can be used safely with other locking &sk_buff functions
+ * safely.
+ *
+ * A buffer cannot be placed on two lists at the same time.
+ */
+void skb_queue_tail(struct sk_buff_head *list, struct sk_buff *newsk)
+{
+ unsigned long flags;
+
+ spin_lock_irqsave(&list->lock, flags);
+ __skb_queue_tail(list, newsk);
+ spin_unlock_irqrestore(&list->lock, flags);
+}
+EXPORT_SYMBOL(skb_queue_tail);
+
+/**
+ * skb_unlink - remove a buffer from a list
+ * @skb: buffer to remove
+ * @list: list to use
+ *
+ * Remove a packet from a list. The list locks are taken and this
+ * function is atomic with respect to other list locked calls
+ *
+ * You must know what list the SKB is on.
+ */
+void skb_unlink(struct sk_buff *skb, struct sk_buff_head *list)
+{
+ unsigned long flags;
+
+ spin_lock_irqsave(&list->lock, flags);
+ __skb_unlink(skb, list);
+ spin_unlock_irqrestore(&list->lock, flags);
+}
+EXPORT_SYMBOL(skb_unlink);
+
+/**
+ * skb_append - append a buffer
+ * @old: buffer to insert after
+ * @newsk: buffer to insert
+ * @list: list to use
+ *
+ * Place a packet after a given packet in a list. The list locks are taken
+ * and this function is atomic with respect to other list locked calls.
+ * A buffer cannot be placed on two lists at the same time.
+ */
+void skb_append(struct sk_buff *old, struct sk_buff *newsk, struct sk_buff_head *list)
+{
+ unsigned long flags;
+
+ spin_lock_irqsave(&list->lock, flags);
+ __skb_queue_after(list, old, newsk);
+ spin_unlock_irqrestore(&list->lock, flags);
+}
+EXPORT_SYMBOL(skb_append);
+
+static inline void skb_split_inside_header(struct sk_buff *skb,
+ struct sk_buff* skb1,
+ const u32 len, const int pos)
+{
+ int i;
+
+ skb_copy_from_linear_data_offset(skb, len, skb_put(skb1, pos - len),
+ pos - len);
+ /* And move data appendix as is. */
+ for (i = 0; i < skb_shinfo(skb)->nr_frags; i++)
+ skb_shinfo(skb1)->frags[i] = skb_shinfo(skb)->frags[i];
+
+ skb_shinfo(skb1)->nr_frags = skb_shinfo(skb)->nr_frags;
+ skb_shinfo(skb)->nr_frags = 0;
+ skb1->data_len = skb->data_len;
+ skb1->len += skb1->data_len;
+ skb->data_len = 0;
+ skb->len = len;
+ skb_set_tail_pointer(skb, len);
+}
+
+static inline void skb_split_no_header(struct sk_buff *skb,
+ struct sk_buff* skb1,
+ const u32 len, int pos)
+{
+ int i, k = 0;
+ const int nfrags = skb_shinfo(skb)->nr_frags;
+
+ skb_shinfo(skb)->nr_frags = 0;
+ skb1->len = skb1->data_len = skb->len - len;
+ skb->len = len;
+ skb->data_len = len - pos;
+
+ for (i = 0; i < nfrags; i++) {
+ int size = skb_frag_size(&skb_shinfo(skb)->frags[i]);
+
+ if (pos + size > len) {
+ skb_shinfo(skb1)->frags[k] = skb_shinfo(skb)->frags[i];
+
+ if (pos < len) {
+ /* Split frag.
+ * We have two variants in this case:
+ * 1. Move all the frag to the second
+ * part, if it is possible. F.e.
+ * this approach is mandatory for TUX,
+ * where splitting is expensive.
+ * 2. Split is accurately. We make this.
+ */
+ skb_frag_ref(skb, i);
+ skb_frag_off_add(&skb_shinfo(skb1)->frags[0], len - pos);
+ skb_frag_size_sub(&skb_shinfo(skb1)->frags[0], len - pos);
+ skb_frag_size_set(&skb_shinfo(skb)->frags[i], len - pos);
+ skb_shinfo(skb)->nr_frags++;
+ }
+ k++;
+ } else
+ skb_shinfo(skb)->nr_frags++;
+ pos += size;
+ }
+ skb_shinfo(skb1)->nr_frags = k;
+}
+
+/**
+ * skb_split - Split fragmented skb to two parts at length len.
+ * @skb: the buffer to split
+ * @skb1: the buffer to receive the second part
+ * @len: new length for skb
+ */
+void skb_split(struct sk_buff *skb, struct sk_buff *skb1, const u32 len)
+{
+ int pos = skb_headlen(skb);
+
+ skb_shinfo(skb1)->tx_flags |= skb_shinfo(skb)->tx_flags &
+ SKBTX_SHARED_FRAG;
+ skb_zerocopy_clone(skb1, skb, 0);
+ if (len < pos) /* Split line is inside header. */
+ skb_split_inside_header(skb, skb1, len, pos);
+ else /* Second chunk has no header, nothing to copy. */
+ skb_split_no_header(skb, skb1, len, pos);
+}
+EXPORT_SYMBOL(skb_split);
+
+/* Shifting from/to a cloned skb is a no-go.
+ *
+ * Caller cannot keep skb_shinfo related pointers past calling here!
+ */
+static int skb_prepare_for_shift(struct sk_buff *skb)
+{
+ int ret = 0;
+
+ if (skb_cloned(skb)) {
+ /* Save and restore truesize: pskb_expand_head() may reallocate
+ * memory where ksize(kmalloc(S)) != ksize(kmalloc(S)), but we
+ * cannot change truesize at this point.
+ */
+ unsigned int save_truesize = skb->truesize;
+
+ ret = pskb_expand_head(skb, 0, 0, GFP_ATOMIC);
+ skb->truesize = save_truesize;
+ }
+ return ret;
+}
+
+/**
+ * skb_shift - Shifts paged data partially from skb to another
+ * @tgt: buffer into which tail data gets added
+ * @skb: buffer from which the paged data comes from
+ * @shiftlen: shift up to this many bytes
+ *
+ * Attempts to shift up to shiftlen worth of bytes, which may be less than
+ * the length of the skb, from skb to tgt. Returns number bytes shifted.
+ * It's up to caller to free skb if everything was shifted.
+ *
+ * If @tgt runs out of frags, the whole operation is aborted.
+ *
+ * Skb cannot include anything else but paged data while tgt is allowed
+ * to have non-paged data as well.
+ *
+ * TODO: full sized shift could be optimized but that would need
+ * specialized skb free'er to handle frags without up-to-date nr_frags.
+ */
+int skb_shift(struct sk_buff *tgt, struct sk_buff *skb, int shiftlen)
+{
+ int from, to, merge, todo;
+ skb_frag_t *fragfrom, *fragto;
+
+ BUG_ON(shiftlen > skb->len);
+
+ if (skb_headlen(skb))
+ return 0;
+ if (skb_zcopy(tgt) || skb_zcopy(skb))
+ return 0;
+
+ todo = shiftlen;
+ from = 0;
+ to = skb_shinfo(tgt)->nr_frags;
+ fragfrom = &skb_shinfo(skb)->frags[from];
+
+ /* Actual merge is delayed until the point when we know we can
+ * commit all, so that we don't have to undo partial changes
+ */
+ if (!to ||
+ !skb_can_coalesce(tgt, to, skb_frag_page(fragfrom),
+ skb_frag_off(fragfrom))) {
+ merge = -1;
+ } else {
+ merge = to - 1;
+
+ todo -= skb_frag_size(fragfrom);
+ if (todo < 0) {
+ if (skb_prepare_for_shift(skb) ||
+ skb_prepare_for_shift(tgt))
+ return 0;
+
+ /* All previous frag pointers might be stale! */
+ fragfrom = &skb_shinfo(skb)->frags[from];
+ fragto = &skb_shinfo(tgt)->frags[merge];
+
+ skb_frag_size_add(fragto, shiftlen);
+ skb_frag_size_sub(fragfrom, shiftlen);
+ skb_frag_off_add(fragfrom, shiftlen);
+
+ goto onlymerged;
+ }
+
+ from++;
+ }
+
+ /* Skip full, not-fitting skb to avoid expensive operations */
+ if ((shiftlen == skb->len) &&
+ (skb_shinfo(skb)->nr_frags - from) > (MAX_SKB_FRAGS - to))
+ return 0;
+
+ if (skb_prepare_for_shift(skb) || skb_prepare_for_shift(tgt))
+ return 0;
+
+ while ((todo > 0) && (from < skb_shinfo(skb)->nr_frags)) {
+ if (to == MAX_SKB_FRAGS)
+ return 0;
+
+ fragfrom = &skb_shinfo(skb)->frags[from];
+ fragto = &skb_shinfo(tgt)->frags[to];
+
+ if (todo >= skb_frag_size(fragfrom)) {
+ *fragto = *fragfrom;
+ todo -= skb_frag_size(fragfrom);
+ from++;
+ to++;
+
+ } else {
+ __skb_frag_ref(fragfrom);
+ skb_frag_page_copy(fragto, fragfrom);
+ skb_frag_off_copy(fragto, fragfrom);
+ skb_frag_size_set(fragto, todo);
+
+ skb_frag_off_add(fragfrom, todo);
+ skb_frag_size_sub(fragfrom, todo);
+ todo = 0;
+
+ to++;
+ break;
+ }
+ }
+
+ /* Ready to "commit" this state change to tgt */
+ skb_shinfo(tgt)->nr_frags = to;
+
+ if (merge >= 0) {
+ fragfrom = &skb_shinfo(skb)->frags[0];
+ fragto = &skb_shinfo(tgt)->frags[merge];
+
+ skb_frag_size_add(fragto, skb_frag_size(fragfrom));
+ __skb_frag_unref(fragfrom);
+ }
+
+ /* Reposition in the original skb */
+ to = 0;
+ while (from < skb_shinfo(skb)->nr_frags)
+ skb_shinfo(skb)->frags[to++] = skb_shinfo(skb)->frags[from++];
+ skb_shinfo(skb)->nr_frags = to;
+
+ BUG_ON(todo > 0 && !skb_shinfo(skb)->nr_frags);
+
+onlymerged:
+ /* Most likely the tgt won't ever need its checksum anymore, skb on
+ * the other hand might need it if it needs to be resent
+ */
+ tgt->ip_summed = CHECKSUM_PARTIAL;
+ skb->ip_summed = CHECKSUM_PARTIAL;
+
+ /* Yak, is it really working this way? Some helper please? */
+ skb->len -= shiftlen;
+ skb->data_len -= shiftlen;
+ skb->truesize -= shiftlen;
+ tgt->len += shiftlen;
+ tgt->data_len += shiftlen;
+ tgt->truesize += shiftlen;
+
+ return shiftlen;
+}
+
+/**
+ * skb_prepare_seq_read - Prepare a sequential read of skb data
+ * @skb: the buffer to read
+ * @from: lower offset of data to be read
+ * @to: upper offset of data to be read
+ * @st: state variable
+ *
+ * Initializes the specified state variable. Must be called before
+ * invoking skb_seq_read() for the first time.
+ */
+void skb_prepare_seq_read(struct sk_buff *skb, unsigned int from,
+ unsigned int to, struct skb_seq_state *st)
+{
+ st->lower_offset = from;
+ st->upper_offset = to;
+ st->root_skb = st->cur_skb = skb;
+ st->frag_idx = st->stepped_offset = 0;
+ st->frag_data = NULL;
+}
+EXPORT_SYMBOL(skb_prepare_seq_read);
+
+/**
+ * skb_seq_read - Sequentially read skb data
+ * @consumed: number of bytes consumed by the caller so far
+ * @data: destination pointer for data to be returned
+ * @st: state variable
+ *
+ * Reads a block of skb data at @consumed relative to the
+ * lower offset specified to skb_prepare_seq_read(). Assigns
+ * the head of the data block to @data and returns the length
+ * of the block or 0 if the end of the skb data or the upper
+ * offset has been reached.
+ *
+ * The caller is not required to consume all of the data
+ * returned, i.e. @consumed is typically set to the number
+ * of bytes already consumed and the next call to
+ * skb_seq_read() will return the remaining part of the block.
+ *
+ * Note 1: The size of each block of data returned can be arbitrary,
+ * this limitation is the cost for zerocopy sequential
+ * reads of potentially non linear data.
+ *
+ * Note 2: Fragment lists within fragments are not implemented
+ * at the moment, state->root_skb could be replaced with
+ * a stack for this purpose.
+ */
+unsigned int skb_seq_read(unsigned int consumed, const u8 **data,
+ struct skb_seq_state *st)
+{
+ unsigned int block_limit, abs_offset = consumed + st->lower_offset;
+ skb_frag_t *frag;
+
+ if (unlikely(abs_offset >= st->upper_offset)) {
+ if (st->frag_data) {
+ kunmap_atomic(st->frag_data);
+ st->frag_data = NULL;
+ }
+ return 0;
+ }
+
+next_skb:
+ block_limit = skb_headlen(st->cur_skb) + st->stepped_offset;
+
+ if (abs_offset < block_limit && !st->frag_data) {
+ *data = st->cur_skb->data + (abs_offset - st->stepped_offset);
+ return block_limit - abs_offset;
+ }
+
+ if (st->frag_idx == 0 && !st->frag_data)
+ st->stepped_offset += skb_headlen(st->cur_skb);
+
+ while (st->frag_idx < skb_shinfo(st->cur_skb)->nr_frags) {
+ frag = &skb_shinfo(st->cur_skb)->frags[st->frag_idx];
+ block_limit = skb_frag_size(frag) + st->stepped_offset;
+
+ if (abs_offset < block_limit) {
+ if (!st->frag_data)
+ st->frag_data = kmap_atomic(skb_frag_page(frag));
+
+ *data = (u8 *) st->frag_data + skb_frag_off(frag) +
+ (abs_offset - st->stepped_offset);
+
+ return block_limit - abs_offset;
+ }
+
+ if (st->frag_data) {
+ kunmap_atomic(st->frag_data);
+ st->frag_data = NULL;
+ }
+
+ st->frag_idx++;
+ st->stepped_offset += skb_frag_size(frag);
+ }
+
+ if (st->frag_data) {
+ kunmap_atomic(st->frag_data);
+ st->frag_data = NULL;
+ }
+
+ if (st->root_skb == st->cur_skb && skb_has_frag_list(st->root_skb)) {
+ st->cur_skb = skb_shinfo(st->root_skb)->frag_list;
+ st->frag_idx = 0;
+ goto next_skb;
+ } else if (st->cur_skb->next) {
+ st->cur_skb = st->cur_skb->next;
+ st->frag_idx = 0;
+ goto next_skb;
+ }
+
+ return 0;
+}
+EXPORT_SYMBOL(skb_seq_read);
+
+/**
+ * skb_abort_seq_read - Abort a sequential read of skb data
+ * @st: state variable
+ *
+ * Must be called if skb_seq_read() was not called until it
+ * returned 0.
+ */
+void skb_abort_seq_read(struct skb_seq_state *st)
+{
+ if (st->frag_data)
+ kunmap_atomic(st->frag_data);
+}
+EXPORT_SYMBOL(skb_abort_seq_read);
+
+#define TS_SKB_CB(state) ((struct skb_seq_state *) &((state)->cb))
+
+static unsigned int skb_ts_get_next_block(unsigned int offset, const u8 **text,
+ struct ts_config *conf,
+ struct ts_state *state)
+{
+ return skb_seq_read(offset, text, TS_SKB_CB(state));
+}
+
+static void skb_ts_finish(struct ts_config *conf, struct ts_state *state)
+{
+ skb_abort_seq_read(TS_SKB_CB(state));
+}
+
+/**
+ * skb_find_text - Find a text pattern in skb data
+ * @skb: the buffer to look in
+ * @from: search offset
+ * @to: search limit
+ * @config: textsearch configuration
+ *
+ * Finds a pattern in the skb data according to the specified
+ * textsearch configuration. Use textsearch_next() to retrieve
+ * subsequent occurrences of the pattern. Returns the offset
+ * to the first occurrence or UINT_MAX if no match was found.
+ */
+unsigned int skb_find_text(struct sk_buff *skb, unsigned int from,
+ unsigned int to, struct ts_config *config)
+{
+ struct ts_state state;
+ unsigned int ret;
+
+ config->get_next_block = skb_ts_get_next_block;
+ config->finish = skb_ts_finish;
+
+ skb_prepare_seq_read(skb, from, to, TS_SKB_CB(&state));
+
+ ret = textsearch_find(config, &state);
+ return (ret <= to - from ? ret : UINT_MAX);
+}
+EXPORT_SYMBOL(skb_find_text);
+
+int skb_append_pagefrags(struct sk_buff *skb, struct page *page,
+ int offset, size_t size)
+{
+ int i = skb_shinfo(skb)->nr_frags;
+
+ if (skb_can_coalesce(skb, i, page, offset)) {
+ skb_frag_size_add(&skb_shinfo(skb)->frags[i - 1], size);
+ } else if (i < MAX_SKB_FRAGS) {
+ get_page(page);
+ skb_fill_page_desc(skb, i, page, offset, size);
+ } else {
+ return -EMSGSIZE;
+ }
+
+ return 0;
+}
+EXPORT_SYMBOL_GPL(skb_append_pagefrags);
+
+/**
+ * skb_pull_rcsum - pull skb and update receive checksum
+ * @skb: buffer to update
+ * @len: length of data pulled
+ *
+ * This function performs an skb_pull on the packet and updates
+ * the CHECKSUM_COMPLETE checksum. It should be used on
+ * receive path processing instead of skb_pull unless you know
+ * that the checksum difference is zero (e.g., a valid IP header)
+ * or you are setting ip_summed to CHECKSUM_NONE.
+ */
+void *skb_pull_rcsum(struct sk_buff *skb, unsigned int len)
+{
+ unsigned char *data = skb->data;
+
+ BUG_ON(len > skb->len);
+ __skb_pull(skb, len);
+ skb_postpull_rcsum(skb, data, len);
+ return skb->data;
+}
+EXPORT_SYMBOL_GPL(skb_pull_rcsum);
+
+static inline skb_frag_t skb_head_frag_to_page_desc(struct sk_buff *frag_skb)
+{
+ skb_frag_t head_frag;
+ struct page *page;
+
+ page = virt_to_head_page(frag_skb->head);
+ __skb_frag_set_page(&head_frag, page);
+ skb_frag_off_set(&head_frag, frag_skb->data -
+ (unsigned char *)page_address(page));
+ skb_frag_size_set(&head_frag, skb_headlen(frag_skb));
+ return head_frag;
+}
+
+struct sk_buff *skb_segment_list(struct sk_buff *skb,
+ netdev_features_t features,
+ unsigned int offset)
+{
+ struct sk_buff *list_skb = skb_shinfo(skb)->frag_list;
+ unsigned int tnl_hlen = skb_tnl_header_len(skb);
+ unsigned int delta_truesize = 0;
+ unsigned int delta_len = 0;
+ struct sk_buff *tail = NULL;
+ struct sk_buff *nskb, *tmp;
+ int len_diff, err;
+
+ skb_push(skb, -skb_network_offset(skb) + offset);
+
+ skb_shinfo(skb)->frag_list = NULL;
+
+ do {
+ nskb = list_skb;
+ list_skb = list_skb->next;
+
+ err = 0;
+ if (skb_shared(nskb)) {
+ tmp = skb_clone(nskb, GFP_ATOMIC);
+ if (tmp) {
+ consume_skb(nskb);
+ nskb = tmp;
+ err = skb_unclone(nskb, GFP_ATOMIC);
+ } else {
+ err = -ENOMEM;
+ }
+ }
+
+ if (!tail)
+ skb->next = nskb;
+ else
+ tail->next = nskb;
+
+ if (unlikely(err)) {
+ nskb->next = list_skb;
+ goto err_linearize;
+ }
+
+ tail = nskb;
+
+ delta_len += nskb->len;
+ delta_truesize += nskb->truesize;
+
+ skb_push(nskb, -skb_network_offset(nskb) + offset);
+
+ skb_release_head_state(nskb);
+ len_diff = skb_network_header_len(nskb) - skb_network_header_len(skb);
+ __copy_skb_header(nskb, skb);
+
+ skb_headers_offset_update(nskb, skb_headroom(nskb) - skb_headroom(skb));
+ nskb->transport_header += len_diff;
+ skb_copy_from_linear_data_offset(skb, -tnl_hlen,
+ nskb->data - tnl_hlen,
+ offset + tnl_hlen);
+
+ if (skb_needs_linearize(nskb, features) &&
+ __skb_linearize(nskb))
+ goto err_linearize;
+
+ } while (list_skb);
+
+ skb->truesize = skb->truesize - delta_truesize;
+ skb->data_len = skb->data_len - delta_len;
+ skb->len = skb->len - delta_len;
+
+ skb_gso_reset(skb);
+
+ skb->prev = tail;
+
+ if (skb_needs_linearize(skb, features) &&
+ __skb_linearize(skb))
+ goto err_linearize;
+
+ skb_get(skb);
+
+ return skb;
+
+err_linearize:
+ kfree_skb_list(skb->next);
+ skb->next = NULL;
+ return ERR_PTR(-ENOMEM);
+}
+EXPORT_SYMBOL_GPL(skb_segment_list);
+
+int skb_gro_receive_list(struct sk_buff *p, struct sk_buff *skb)
+{
+ if (unlikely(p->len + skb->len >= 65536))
+ return -E2BIG;
+
+ if (skb_shinfo_is_ptr(skb))
+ skb_shinfo(p)->gso_type |= SKB_GSO_DODGY;
+
+ if (NAPI_GRO_CB(p)->last == p)
+ skb_shinfo(p)->frag_list = skb;
+ else
+ NAPI_GRO_CB(p)->last->next = skb;
+
+ skb_pull(skb, skb_gro_offset(skb));
+
+ NAPI_GRO_CB(p)->last = skb;
+ NAPI_GRO_CB(p)->count++;
+ p->data_len += skb->len;
+ p->truesize += skb->truesize;
+ p->len += skb->len;
+
+ NAPI_GRO_CB(skb)->same_flow = 1;
+
+ return 0;
+}
+EXPORT_SYMBOL_GPL(skb_gro_receive_list);
+
+/**
+ * skb_segment - Perform protocol segmentation on skb.
+ * @head_skb: buffer to segment
+ * @features: features for the output path (see dev->features)
+ *
+ * This function performs segmentation on the given skb. It returns
+ * a pointer to the first in a list of new skbs for the segments.
+ * In case of error it returns ERR_PTR(err).
+ */
+struct sk_buff *skb_segment(struct sk_buff *head_skb,
+ netdev_features_t features)
+{
+ struct sk_buff *segs = NULL;
+ struct sk_buff *tail = NULL;
+ struct sk_buff *list_skb = skb_shinfo(head_skb)->frag_list;
+ unsigned int mss = skb_shinfo(head_skb)->gso_size;
+ unsigned int doffset = head_skb->data - skb_mac_header(head_skb);
+ unsigned int offset = doffset;
+ unsigned int tnl_hlen = skb_tnl_header_len(head_skb);
+ unsigned int partial_segs = 0;
+ unsigned int headroom;
+ unsigned int len = head_skb->len;
+ struct sk_buff *frag_skb;
+ skb_frag_t *frag;
+ __be16 proto;
+ bool csum, sg;
+ int err = -ENOMEM;
+ int i = 0;
+ int nfrags, pos;
+ int dummy;
+
+ if ((skb_shinfo(head_skb)->gso_type & SKB_GSO_DODGY) &&
+ mss != GSO_BY_FRAGS && mss != skb_headlen(head_skb)) {
+ struct sk_buff *check_skb;
+
+ for (check_skb = list_skb; check_skb; check_skb = check_skb->next) {
+ if (skb_headlen(check_skb) && !check_skb->head_frag) {
+ /* gso_size is untrusted, and we have a frag_list with
+ * a linear non head_frag item.
+ *
+ * If head_skb's headlen does not fit requested gso_size,
+ * it means that the frag_list members do NOT terminate
+ * on exact gso_size boundaries. Hence we cannot perform
+ * skb_frag_t page sharing. Therefore we must fallback to
+ * copying the frag_list skbs; we do so by disabling SG.
+ */
+ features &= ~NETIF_F_SG;
+ break;
+ }
+ }
+ }
+
+ __skb_push(head_skb, doffset);
+ proto = skb_network_protocol(head_skb, &dummy);
+ if (unlikely(!proto))
+ return ERR_PTR(-EINVAL);
+
+ sg = !!(features & NETIF_F_SG);
+ csum = !!can_checksum_protocol(features, proto);
+
+ if (sg && csum && (mss != GSO_BY_FRAGS)) {
+ if (!(features & NETIF_F_GSO_PARTIAL)) {
+ struct sk_buff *iter;
+ unsigned int frag_len;
+
+ if (!list_skb ||
+ !net_gso_ok(features, skb_shinfo(head_skb)->gso_type))
+ goto normal;
+
+ /* If we get here then all the required
+ * GSO features except frag_list are supported.
+ * Try to split the SKB to multiple GSO SKBs
+ * with no frag_list.
+ * Currently we can do that only when the buffers don't
+ * have a linear part and all the buffers except
+ * the last are of the same length.
+ */
+ frag_len = list_skb->len;
+ skb_walk_frags(head_skb, iter) {
+ if (frag_len != iter->len && iter->next)
+ goto normal;
+ if (skb_headlen(iter) && !iter->head_frag)
+ goto normal;
+
+ len -= iter->len;
+ }
+
+ if (len != frag_len)
+ goto normal;
+ }
+
+ /* GSO partial only requires that we trim off any excess that
+ * doesn't fit into an MSS sized block, so take care of that
+ * now.
+ * Cap len to not accidentally hit GSO_BY_FRAGS.
+ */
+ partial_segs = min(len, GSO_BY_FRAGS - 1U) / mss;
+ if (partial_segs > 1)
+ mss *= partial_segs;
+ else
+ partial_segs = 0;
+ }
+
+normal:
+ headroom = skb_headroom(head_skb);
+ pos = skb_headlen(head_skb);
+
+ if (skb_orphan_frags(head_skb, GFP_ATOMIC))
+ return ERR_PTR(-ENOMEM);
+
+ nfrags = skb_shinfo(head_skb)->nr_frags;
+ frag = skb_shinfo(head_skb)->frags;
+ frag_skb = head_skb;
+
+ do {
+ struct sk_buff *nskb;
+ skb_frag_t *nskb_frag;
+ int hsize;
+ int size;
+
+ if (unlikely(mss == GSO_BY_FRAGS)) {
+ len = list_skb->len;
+ } else {
+ len = head_skb->len - offset;
+ if (len > mss)
+ len = mss;
+ }
+
+ hsize = skb_headlen(head_skb) - offset;
+ if (hsize < 0)
+ hsize = 0;
+ if (hsize > len || !sg)
+ hsize = len;
+
+ if (!hsize && i >= nfrags && skb_headlen(list_skb) &&
+ (skb_headlen(list_skb) == len || sg)) {
+ BUG_ON(skb_headlen(list_skb) > len);
+
+ nskb = skb_clone(list_skb, GFP_ATOMIC);
+ if (unlikely(!nskb))
+ goto err;
+
+ i = 0;
+ nfrags = skb_shinfo(list_skb)->nr_frags;
+ frag = skb_shinfo(list_skb)->frags;
+ frag_skb = list_skb;
+ pos += skb_headlen(list_skb);
+
+ while (pos < offset + len) {
+ BUG_ON(i >= nfrags);
+
+ size = skb_frag_size(frag);
+ if (pos + size > offset + len)
+ break;
+
+ i++;
+ pos += size;
+ frag++;
+ }
+
+ list_skb = list_skb->next;
+
+ if (unlikely(pskb_trim(nskb, len))) {
+ kfree_skb(nskb);
+ goto err;
+ }
+
+ hsize = skb_end_offset(nskb);
+ if (skb_cow_head(nskb, doffset + headroom)) {
+ kfree_skb(nskb);
+ goto err;
+ }
+
+ nskb->truesize += skb_end_offset(nskb) - hsize;
+ skb_release_head_state(nskb);
+ __skb_push(nskb, doffset);
+ } else {
+ nskb = __alloc_skb(hsize + doffset + headroom,
+ GFP_ATOMIC, skb_alloc_rx_flag(head_skb),
+ NUMA_NO_NODE);
+
+ if (unlikely(!nskb))
+ goto err;
+
+ skb_reserve(nskb, headroom);
+ __skb_put(nskb, doffset);
+ }
+
+ if (segs)
+ tail->next = nskb;
+ else
+ segs = nskb;
+ tail = nskb;
+
+ __copy_skb_header(nskb, head_skb);
+
+ skb_headers_offset_update(nskb, skb_headroom(nskb) - headroom);
+ skb_reset_mac_len(nskb);
+
+ skb_copy_from_linear_data_offset(head_skb, -tnl_hlen,
+ nskb->data - tnl_hlen,
+ doffset + tnl_hlen);
+
+ if (nskb->len == len + doffset)
+ goto perform_csum_check;
+
+ if (!sg) {
+ if (!nskb->remcsum_offload)
+ nskb->ip_summed = CHECKSUM_NONE;
+ SKB_GSO_CB(nskb)->csum =
+ skb_copy_and_csum_bits(head_skb, offset,
+ skb_put(nskb, len),
+ len, 0);
+ SKB_GSO_CB(nskb)->csum_start =
+ skb_headroom(nskb) + doffset;
+ continue;
+ }
+
+ nskb_frag = skb_shinfo(nskb)->frags;
+
+ skb_copy_from_linear_data_offset(head_skb, offset,
+ skb_put(nskb, hsize), hsize);
+
+ skb_shinfo(nskb)->tx_flags |= skb_shinfo(head_skb)->tx_flags &
+ SKBTX_SHARED_FRAG;
+
+ if (skb_zerocopy_clone(nskb, frag_skb, GFP_ATOMIC))
+ goto err;
+
+ while (pos < offset + len) {
+ if (i >= nfrags) {
+ if (skb_orphan_frags(list_skb, GFP_ATOMIC) ||
+ skb_zerocopy_clone(nskb, list_skb,
+ GFP_ATOMIC))
+ goto err;
+
+ i = 0;
+ nfrags = skb_shinfo(list_skb)->nr_frags;
+ frag = skb_shinfo(list_skb)->frags;
+ frag_skb = list_skb;
+ if (!skb_headlen(list_skb)) {
+ BUG_ON(!nfrags);
+ } else {
+ BUG_ON(!list_skb->head_frag);
+
+ /* to make room for head_frag. */
+ i--;
+ frag--;
+ }
+
+ list_skb = list_skb->next;
+ }
+
+ if (unlikely(skb_shinfo(nskb)->nr_frags >=
+ MAX_SKB_FRAGS)) {
+ net_warn_ratelimited(
+ "skb_segment: too many frags: %u %u\n",
+ pos, mss);
+ err = -EINVAL;
+ goto err;
+ }
+
+ *nskb_frag = (i < 0) ? skb_head_frag_to_page_desc(frag_skb) : *frag;
+ __skb_frag_ref(nskb_frag);
+ size = skb_frag_size(nskb_frag);
+
+ if (pos < offset) {
+ skb_frag_off_add(nskb_frag, offset - pos);
+ skb_frag_size_sub(nskb_frag, offset - pos);
+ }
+
+ skb_shinfo(nskb)->nr_frags++;
+
+ if (pos + size <= offset + len) {
+ i++;
+ frag++;
+ pos += size;
+ } else {
+ skb_frag_size_sub(nskb_frag, pos + size - (offset + len));
+ goto skip_fraglist;
+ }
+
+ nskb_frag++;
+ }
+
+skip_fraglist:
+ nskb->data_len = len - hsize;
+ nskb->len += nskb->data_len;
+ nskb->truesize += nskb->data_len;
+
+perform_csum_check:
+ if (!csum) {
+ if (skb_has_shared_frag(nskb) &&
+ __skb_linearize(nskb))
+ goto err;
+
+ if (!nskb->remcsum_offload)
+ nskb->ip_summed = CHECKSUM_NONE;
+ SKB_GSO_CB(nskb)->csum =
+ skb_checksum(nskb, doffset,
+ nskb->len - doffset, 0);
+ SKB_GSO_CB(nskb)->csum_start =
+ skb_headroom(nskb) + doffset;
+ }
+ } while ((offset += len) < head_skb->len);
+
+ /* Some callers want to get the end of the list.
+ * Put it in segs->prev to avoid walking the list.
+ * (see validate_xmit_skb_list() for example)
+ */
+ segs->prev = tail;
+
+ if (partial_segs) {
+ struct sk_buff *iter;
+ int type = skb_shinfo(head_skb)->gso_type;
+ unsigned short gso_size = skb_shinfo(head_skb)->gso_size;
+
+ /* Update type to add partial and then remove dodgy if set */
+ type |= (features & NETIF_F_GSO_PARTIAL) / NETIF_F_GSO_PARTIAL * SKB_GSO_PARTIAL;
+ type &= ~SKB_GSO_DODGY;
+
+ /* Update GSO info and prepare to start updating headers on
+ * our way back down the stack of protocols.
+ */
+ for (iter = segs; iter; iter = iter->next) {
+ skb_shinfo(iter)->gso_size = gso_size;
+ skb_shinfo(iter)->gso_segs = partial_segs;
+ skb_shinfo(iter)->gso_type = type;
+ SKB_GSO_CB(iter)->data_offset = skb_headroom(iter) + doffset;
+ }
+
+ if (tail->len - doffset <= gso_size)
+ skb_shinfo(tail)->gso_size = 0;
+ else if (tail != segs)
+ skb_shinfo(tail)->gso_segs = DIV_ROUND_UP(tail->len - doffset, gso_size);
+ }
+
+ /* Following permits correct backpressure, for protocols
+ * using skb_set_owner_w().
+ * Idea is to tranfert ownership from head_skb to last segment.
+ */
+ if (head_skb->destructor == sock_wfree) {
+ swap(tail->truesize, head_skb->truesize);
+ swap(tail->destructor, head_skb->destructor);
+ swap(tail->sk, head_skb->sk);
+ }
+ return segs;
+
+err:
+ kfree_skb_list(segs);
+ return ERR_PTR(err);
+}
+EXPORT_SYMBOL_GPL(skb_segment);
+
+int skb_gro_receive(struct sk_buff *p, struct sk_buff *skb)
+{
+ struct skb_shared_info *pinfo, *skbinfo = skb_shinfo(skb);
+ unsigned int offset = skb_gro_offset(skb);
+ unsigned int headlen = skb_headlen(skb);
+ unsigned int len = skb_gro_len(skb);
+ unsigned int delta_truesize;
+ struct sk_buff *lp;
+
+ if (unlikely(p->len + len >= 65536 || NAPI_GRO_CB(skb)->flush))
+ return -E2BIG;
+
+ lp = NAPI_GRO_CB(p)->last;
+ pinfo = skb_shinfo(lp);
+
+ if (headlen <= offset) {
+ skb_frag_t *frag;
+ skb_frag_t *frag2;
+ int i = skbinfo->nr_frags;
+ int nr_frags = pinfo->nr_frags + i;
+
+ if (nr_frags > MAX_SKB_FRAGS)
+ goto merge;
+
+ offset -= headlen;
+ pinfo->nr_frags = nr_frags;
+ skbinfo->nr_frags = 0;
+
+ frag = pinfo->frags + nr_frags;
+ frag2 = skbinfo->frags + i;
+ do {
+ *--frag = *--frag2;
+ } while (--i);
+
+ skb_frag_off_add(frag, offset);
+ skb_frag_size_sub(frag, offset);
+
+ /* all fragments truesize : remove (head size + sk_buff) */
+ delta_truesize = skb->truesize -
+ SKB_TRUESIZE(skb_end_offset(skb));
+
+ skb->truesize -= skb->data_len;
+ skb->len -= skb->data_len;
+ skb->data_len = 0;
+
+ NAPI_GRO_CB(skb)->free = NAPI_GRO_FREE;
+ goto done;
+ } else if (skb->head_frag) {
+ int nr_frags = pinfo->nr_frags;
+ skb_frag_t *frag = pinfo->frags + nr_frags;
+ struct page *page = virt_to_head_page(skb->head);
+ unsigned int first_size = headlen - offset;
+ unsigned int first_offset;
+
+ if (nr_frags + 1 + skbinfo->nr_frags > MAX_SKB_FRAGS)
+ goto merge;
+
+ first_offset = skb->data -
+ (unsigned char *)page_address(page) +
+ offset;
+
+ pinfo->nr_frags = nr_frags + 1 + skbinfo->nr_frags;
+
+ __skb_frag_set_page(frag, page);
+ skb_frag_off_set(frag, first_offset);
+ skb_frag_size_set(frag, first_size);
+
+ memcpy(frag + 1, skbinfo->frags, sizeof(*frag) * skbinfo->nr_frags);
+ /* We dont need to clear skbinfo->nr_frags here */
+
+ delta_truesize = skb->truesize - SKB_DATA_ALIGN(sizeof(struct sk_buff));
+ NAPI_GRO_CB(skb)->free = NAPI_GRO_FREE_STOLEN_HEAD;
+ goto done;
+ }
+
+merge:
+ delta_truesize = skb->truesize;
+ if (offset > headlen) {
+ unsigned int eat = offset - headlen;
+
+ skb_frag_off_add(&skbinfo->frags[0], eat);
+ skb_frag_size_sub(&skbinfo->frags[0], eat);
+ skb->data_len -= eat;
+ skb->len -= eat;
+ offset = headlen;
+ }
+
+ __skb_pull(skb, offset);
+
+ if (skb_shinfo_is_ptr(skb))
+ skb_shinfo(p)->gso_type |= SKB_GSO_DODGY;
+
+ if (NAPI_GRO_CB(p)->last == p)
+ skb_shinfo(p)->frag_list = skb;
+ else
+ NAPI_GRO_CB(p)->last->next = skb;
+ NAPI_GRO_CB(p)->last = skb;
+ __skb_header_release(skb);
+ lp = p;
+
+done:
+ NAPI_GRO_CB(p)->count++;
+ p->data_len += len;
+ p->truesize += delta_truesize;
+ p->len += len;
+ if (lp != p) {
+ lp->data_len += len;
+ lp->truesize += delta_truesize;
+ lp->len += len;
+ }
+ NAPI_GRO_CB(skb)->same_flow = 1;
+ return 0;
+}
+EXPORT_SYMBOL_GPL(skb_gro_receive);
+
+#ifdef CONFIG_SKB_EXTENSIONS
+#define SKB_EXT_ALIGN_VALUE 8
+#define SKB_EXT_CHUNKSIZEOF(x) (ALIGN((sizeof(x)), SKB_EXT_ALIGN_VALUE) / SKB_EXT_ALIGN_VALUE)
+
+static const u8 skb_ext_type_len[] = {
+#if IS_ENABLED(CONFIG_BRIDGE_NETFILTER)
+ [SKB_EXT_BRIDGE_NF] = SKB_EXT_CHUNKSIZEOF(struct nf_bridge_info),
+#endif
+#ifdef CONFIG_XFRM
+ [SKB_EXT_SEC_PATH] = SKB_EXT_CHUNKSIZEOF(struct sec_path),
+#endif
+#if IS_ENABLED(CONFIG_NET_TC_SKB_EXT)
+ [TC_SKB_EXT] = SKB_EXT_CHUNKSIZEOF(struct tc_skb_ext),
+#endif
+};
+
+static __always_inline unsigned int skb_ext_total_length(void)
+{
+ return SKB_EXT_CHUNKSIZEOF(struct skb_ext) +
+#if IS_ENABLED(CONFIG_BRIDGE_NETFILTER)
+ skb_ext_type_len[SKB_EXT_BRIDGE_NF] +
+#endif
+#ifdef CONFIG_XFRM
+ skb_ext_type_len[SKB_EXT_SEC_PATH] +
+#endif
+#if IS_ENABLED(CONFIG_NET_TC_SKB_EXT)
+ skb_ext_type_len[TC_SKB_EXT] +
+#endif
+ 0;
+}
+
+static void skb_extensions_init(void)
+{
+ BUILD_BUG_ON(SKB_EXT_NUM >= 8);
+ BUILD_BUG_ON(skb_ext_total_length() > 255);
+
+ skbuff_ext_cache = kmem_cache_create("skbuff_ext_cache",
+ SKB_EXT_ALIGN_VALUE * skb_ext_total_length(),
+ 0,
+ SLAB_HWCACHE_ALIGN|SLAB_PANIC,
+ NULL);
+}
+#else
+static void skb_extensions_init(void) {}
+#endif
+
+void __init skb_init(void)
+{
+ skbuff_head_cache = kmem_cache_create_usercopy("skbuff_head_cache",
+ sizeof(struct sk_buff),
+ 0,
+ SLAB_HWCACHE_ALIGN|SLAB_PANIC,
+ offsetof(struct sk_buff, cb),
+ sizeof_field(struct sk_buff, cb),
+ NULL);
+ skbuff_fclone_cache = kmem_cache_create("skbuff_fclone_cache",
+ sizeof(struct sk_buff_fclones),
+ 0,
+ SLAB_HWCACHE_ALIGN|SLAB_PANIC,
+ NULL);
+ skb_extensions_init();
+}
+
+static int
+__skb_to_sgvec(struct sk_buff *skb, struct scatterlist *sg, int offset, int len,
+ unsigned int recursion_level)
+{
+ int start = skb_headlen(skb);
+ int i, copy = start - offset;
+ struct sk_buff *frag_iter;
+ int elt = 0;
+
+ if (unlikely(recursion_level >= 24))
+ return -EMSGSIZE;
+
+ if (copy > 0) {
+ if (copy > len)
+ copy = len;
+ sg_set_buf(sg, skb->data + offset, copy);
+ elt++;
+ if ((len -= copy) == 0)
+ return elt;
+ offset += copy;
+ }
+
+ for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
+ int end;
+
+ WARN_ON(start > offset + len);
+
+ end = start + skb_frag_size(&skb_shinfo(skb)->frags[i]);
+ if ((copy = end - offset) > 0) {
+ skb_frag_t *frag = &skb_shinfo(skb)->frags[i];
+ if (unlikely(elt && sg_is_last(&sg[elt - 1])))
+ return -EMSGSIZE;
+
+ if (copy > len)
+ copy = len;
+ sg_set_page(&sg[elt], skb_frag_page(frag), copy,
+ skb_frag_off(frag) + offset - start);
+ elt++;
+ if (!(len -= copy))
+ return elt;
+ offset += copy;
+ }
+ start = end;
+ }
+
+ skb_walk_frags(skb, frag_iter) {
+ int end, ret;
+
+ WARN_ON(start > offset + len);
+
+ end = start + frag_iter->len;
+ if ((copy = end - offset) > 0) {
+ if (unlikely(elt && sg_is_last(&sg[elt - 1])))
+ return -EMSGSIZE;
+
+ if (copy > len)
+ copy = len;
+ ret = __skb_to_sgvec(frag_iter, sg+elt, offset - start,
+ copy, recursion_level + 1);
+ if (unlikely(ret < 0))
+ return ret;
+ elt += ret;
+ if ((len -= copy) == 0)
+ return elt;
+ offset += copy;
+ }
+ start = end;
+ }
+ BUG_ON(len);
+ return elt;
+}
+
+/**
+ * skb_to_sgvec - Fill a scatter-gather list from a socket buffer
+ * @skb: Socket buffer containing the buffers to be mapped
+ * @sg: The scatter-gather list to map into
+ * @offset: The offset into the buffer's contents to start mapping
+ * @len: Length of buffer space to be mapped
+ *
+ * Fill the specified scatter-gather list with mappings/pointers into a
+ * region of the buffer space attached to a socket buffer. Returns either
+ * the number of scatterlist items used, or -EMSGSIZE if the contents
+ * could not fit.
+ */
+int skb_to_sgvec(struct sk_buff *skb, struct scatterlist *sg, int offset, int len)
+{
+ int nsg = __skb_to_sgvec(skb, sg, offset, len, 0);
+
+ if (nsg <= 0)
+ return nsg;
+
+ sg_mark_end(&sg[nsg - 1]);
+
+ return nsg;
+}
+EXPORT_SYMBOL_GPL(skb_to_sgvec);
+
+/* As compared with skb_to_sgvec, skb_to_sgvec_nomark only map skb to given
+ * sglist without mark the sg which contain last skb data as the end.
+ * So the caller can mannipulate sg list as will when padding new data after
+ * the first call without calling sg_unmark_end to expend sg list.
+ *
+ * Scenario to use skb_to_sgvec_nomark:
+ * 1. sg_init_table
+ * 2. skb_to_sgvec_nomark(payload1)
+ * 3. skb_to_sgvec_nomark(payload2)
+ *
+ * This is equivalent to:
+ * 1. sg_init_table
+ * 2. skb_to_sgvec(payload1)
+ * 3. sg_unmark_end
+ * 4. skb_to_sgvec(payload2)
+ *
+ * When mapping mutilple payload conditionally, skb_to_sgvec_nomark
+ * is more preferable.
+ */
+int skb_to_sgvec_nomark(struct sk_buff *skb, struct scatterlist *sg,
+ int offset, int len)
+{
+ return __skb_to_sgvec(skb, sg, offset, len, 0);
+}
+EXPORT_SYMBOL_GPL(skb_to_sgvec_nomark);
+
+
+
+/**
+ * skb_cow_data - Check that a socket buffer's data buffers are writable
+ * @skb: The socket buffer to check.
+ * @tailbits: Amount of trailing space to be added
+ * @trailer: Returned pointer to the skb where the @tailbits space begins
+ *
+ * Make sure that the data buffers attached to a socket buffer are
+ * writable. If they are not, private copies are made of the data buffers
+ * and the socket buffer is set to use these instead.
+ *
+ * If @tailbits is given, make sure that there is space to write @tailbits
+ * bytes of data beyond current end of socket buffer. @trailer will be
+ * set to point to the skb in which this space begins.
+ *
+ * The number of scatterlist elements required to completely map the
+ * COW'd and extended socket buffer will be returned.
+ */
+int skb_cow_data(struct sk_buff *skb, int tailbits, struct sk_buff **trailer)
+{
+ int copyflag;
+ int elt;
+ struct sk_buff *skb1, **skb_p;
+
+ /* If skb is cloned or its head is paged, reallocate
+ * head pulling out all the pages (pages are considered not writable
+ * at the moment even if they are anonymous).
+ */
+ if ((skb_cloned(skb) || skb_shinfo(skb)->nr_frags) &&
+ __pskb_pull_tail(skb, skb_pagelen(skb)-skb_headlen(skb)) == NULL)
+ return -ENOMEM;
+
+ /* Easy case. Most of packets will go this way. */
+ if (!skb_has_frag_list(skb)) {
+ /* A little of trouble, not enough of space for trailer.
+ * This should not happen, when stack is tuned to generate
+ * good frames. OK, on miss we reallocate and reserve even more
+ * space, 128 bytes is fair. */
+
+ if (skb_tailroom(skb) < tailbits &&
+ pskb_expand_head(skb, 0, tailbits-skb_tailroom(skb)+128, GFP_ATOMIC))
+ return -ENOMEM;
+
+ /* Voila! */
+ *trailer = skb;
+ return 1;
+ }
+
+ /* Misery. We are in troubles, going to mincer fragments... */
+
+ elt = 1;
+ skb_p = &skb_shinfo(skb)->frag_list;
+ copyflag = 0;
+
+ while ((skb1 = *skb_p) != NULL) {
+ int ntail = 0;
+
+ /* The fragment is partially pulled by someone,
+ * this can happen on input. Copy it and everything
+ * after it. */
+
+ if (skb_shared(skb1))
+ copyflag = 1;
+
+ /* If the skb is the last, worry about trailer. */
+
+ if (skb1->next == NULL && tailbits) {
+ if (skb_shinfo(skb1)->nr_frags ||
+ skb_has_frag_list(skb1) ||
+ skb_tailroom(skb1) < tailbits)
+ ntail = tailbits + 128;
+ }
+
+ if (copyflag ||
+ skb_cloned(skb1) ||
+ ntail ||
+ skb_shinfo(skb1)->nr_frags ||
+ skb_has_frag_list(skb1)) {
+ struct sk_buff *skb2;
+
+ /* Fuck, we are miserable poor guys... */
+ if (ntail == 0)
+ skb2 = skb_copy(skb1, GFP_ATOMIC);
+ else
+ skb2 = skb_copy_expand(skb1,
+ skb_headroom(skb1),
+ ntail,
+ GFP_ATOMIC);
+ if (unlikely(skb2 == NULL))
+ return -ENOMEM;
+
+ if (skb1->sk)
+ skb_set_owner_w(skb2, skb1->sk);
+
+ /* Looking around. Are we still alive?
+ * OK, link new skb, drop old one */
+
+ skb2->next = skb1->next;
+ *skb_p = skb2;
+ kfree_skb(skb1);
+ skb1 = skb2;
+ }
+ elt++;
+ *trailer = skb1;
+ skb_p = &skb1->next;
+ }
+
+ return elt;
+}
+EXPORT_SYMBOL_GPL(skb_cow_data);
+
+static void sock_rmem_free(struct sk_buff *skb)
+{
+ struct sock *sk = skb->sk;
+
+ atomic_sub(skb->truesize, &sk->sk_rmem_alloc);
+}
+
+static void skb_set_err_queue(struct sk_buff *skb)
+{
+ /* pkt_type of skbs received on local sockets is never PACKET_OUTGOING.
+ * So, it is safe to (mis)use it to mark skbs on the error queue.
+ */
+ skb->pkt_type = PACKET_OUTGOING;
+ BUILD_BUG_ON(PACKET_OUTGOING == 0);
+}
+
+/*
+ * Note: We dont mem charge error packets (no sk_forward_alloc changes)
+ */
+int sock_queue_err_skb(struct sock *sk, struct sk_buff *skb)
+{
+ if (atomic_read(&sk->sk_rmem_alloc) + skb->truesize >=
+ (unsigned int)READ_ONCE(sk->sk_rcvbuf))
+ return -ENOMEM;
+
+ skb_orphan(skb);
+ skb->sk = sk;
+ skb->destructor = sock_rmem_free;
+ atomic_add(skb->truesize, &sk->sk_rmem_alloc);
+ skb_set_err_queue(skb);
+
+ /* before exiting rcu section, make sure dst is refcounted */
+ skb_dst_force(skb);
+
+ skb_queue_tail(&sk->sk_error_queue, skb);
+ if (!sock_flag(sk, SOCK_DEAD))
+ sk->sk_error_report(sk);
+ return 0;
+}
+EXPORT_SYMBOL(sock_queue_err_skb);
+
+static bool is_icmp_err_skb(const struct sk_buff *skb)
+{
+ return skb && (SKB_EXT_ERR(skb)->ee.ee_origin == SO_EE_ORIGIN_ICMP ||
+ SKB_EXT_ERR(skb)->ee.ee_origin == SO_EE_ORIGIN_ICMP6);
+}
+
+struct sk_buff *sock_dequeue_err_skb(struct sock *sk)
+{
+ struct sk_buff_head *q = &sk->sk_error_queue;
+ struct sk_buff *skb, *skb_next = NULL;
+ bool icmp_next = false;
+ unsigned long flags;
+
+ spin_lock_irqsave(&q->lock, flags);
+ skb = __skb_dequeue(q);
+ if (skb && (skb_next = skb_peek(q))) {
+ icmp_next = is_icmp_err_skb(skb_next);
+ if (icmp_next)
+ sk->sk_err = SKB_EXT_ERR(skb_next)->ee.ee_errno;
+ }
+ spin_unlock_irqrestore(&q->lock, flags);
+
+ if (is_icmp_err_skb(skb) && !icmp_next)
+ sk->sk_err = 0;
+
+ if (skb_next)
+ sk->sk_error_report(sk);
+
+ return skb;
+}
+EXPORT_SYMBOL(sock_dequeue_err_skb);
+
+/**
+ * skb_clone_sk - create clone of skb, and take reference to socket
+ * @skb: the skb to clone
+ *
+ * This function creates a clone of a buffer that holds a reference on
+ * sk_refcnt. Buffers created via this function are meant to be
+ * returned using sock_queue_err_skb, or free via kfree_skb.
+ *
+ * When passing buffers allocated with this function to sock_queue_err_skb
+ * it is necessary to wrap the call with sock_hold/sock_put in order to
+ * prevent the socket from being released prior to being enqueued on
+ * the sk_error_queue.
+ */
+struct sk_buff *skb_clone_sk(struct sk_buff *skb)
+{
+ struct sock *sk = skb->sk;
+ struct sk_buff *clone;
+
+ if (!sk || !refcount_inc_not_zero(&sk->sk_refcnt))
+ return NULL;
+
+ clone = skb_clone(skb, GFP_ATOMIC);
+ if (!clone) {
+ sock_put(sk);
+ return NULL;
+ }
+
+ clone->sk = sk;
+ clone->destructor = sock_efree;
+
+ return clone;
+}
+EXPORT_SYMBOL(skb_clone_sk);
+
+static void __skb_complete_tx_timestamp(struct sk_buff *skb,
+ struct sock *sk,
+ int tstype,
+ bool opt_stats)
+{
+ struct sock_exterr_skb *serr;
+ int err;
+
+ BUILD_BUG_ON(sizeof(struct sock_exterr_skb) > sizeof(skb->cb));
+
+ serr = SKB_EXT_ERR(skb);
+ memset(serr, 0, sizeof(*serr));
+ serr->ee.ee_errno = ENOMSG;
+ serr->ee.ee_origin = SO_EE_ORIGIN_TIMESTAMPING;
+ serr->ee.ee_info = tstype;
+ serr->opt_stats = opt_stats;
+ serr->header.h4.iif = skb->dev ? skb->dev->ifindex : 0;
+ if (sk->sk_tsflags & SOF_TIMESTAMPING_OPT_ID) {
+ serr->ee.ee_data = skb_shinfo(skb)->tskey;
+ if (sk->sk_protocol == IPPROTO_TCP &&
+ sk->sk_type == SOCK_STREAM)
+ serr->ee.ee_data -= sk->sk_tskey;
+ }
+
+ err = sock_queue_err_skb(sk, skb);
+
+ if (err)
+ kfree_skb(skb);
+}
+
+static bool skb_may_tx_timestamp(struct sock *sk, bool tsonly)
+{
+ bool ret;
+
+ if (likely(READ_ONCE(sysctl_tstamp_allow_data) || tsonly))
+ return true;
+
+ read_lock_bh(&sk->sk_callback_lock);
+ ret = sk->sk_socket && sk->sk_socket->file &&
+ file_ns_capable(sk->sk_socket->file, &init_user_ns, CAP_NET_RAW);
+ read_unlock_bh(&sk->sk_callback_lock);
+ return ret;
+}
+
+void skb_complete_tx_timestamp(struct sk_buff *skb,
+ struct skb_shared_hwtstamps *hwtstamps)
+{
+ struct sock *sk = skb->sk;
+
+ if (!skb_may_tx_timestamp(sk, false))
+ goto err;
+
+ /* Take a reference to prevent skb_orphan() from freeing the socket,
+ * but only if the socket refcount is not zero.
+ */
+ if (likely(refcount_inc_not_zero(&sk->sk_refcnt))) {
+ *skb_hwtstamps(skb) = *hwtstamps;
+ __skb_complete_tx_timestamp(skb, sk, SCM_TSTAMP_SND, false);
+ sock_put(sk);
+ return;
+ }
+
+err:
+ kfree_skb(skb);
+}
+EXPORT_SYMBOL_GPL(skb_complete_tx_timestamp);
+
+void __skb_tstamp_tx(struct sk_buff *orig_skb,
+ struct skb_shared_hwtstamps *hwtstamps,
+ struct sock *sk, int tstype)
+{
+ struct sk_buff *skb;
+ bool tsonly, opt_stats = false;
+
+ if (!sk)
+ return;
+
+ if (!hwtstamps && !(sk->sk_tsflags & SOF_TIMESTAMPING_OPT_TX_SWHW) &&
+ skb_shinfo(orig_skb)->tx_flags & SKBTX_IN_PROGRESS)
+ return;
+
+ tsonly = sk->sk_tsflags & SOF_TIMESTAMPING_OPT_TSONLY;
+ if (!skb_may_tx_timestamp(sk, tsonly))
+ return;
+
+ if (tsonly) {
+#ifdef CONFIG_INET
+ if ((sk->sk_tsflags & SOF_TIMESTAMPING_OPT_STATS) &&
+ sk->sk_protocol == IPPROTO_TCP &&
+ sk->sk_type == SOCK_STREAM) {
+ skb = tcp_get_timestamping_opt_stats(sk);
+ opt_stats = true;
+ } else
+#endif
+ skb = alloc_skb(0, GFP_ATOMIC);
+ } else {
+ skb = skb_clone(orig_skb, GFP_ATOMIC);
+
+ if (skb_orphan_frags_rx(skb, GFP_ATOMIC)) {
+ kfree_skb(skb);
+ return;
+ }
+ }
+ if (!skb)
+ return;
+
+ if (tsonly) {
+ skb_shinfo(skb)->tx_flags |= skb_shinfo(orig_skb)->tx_flags &
+ SKBTX_ANY_TSTAMP;
+ skb_shinfo(skb)->tskey = skb_shinfo(orig_skb)->tskey;
+ }
+
+ if (hwtstamps)
+ *skb_hwtstamps(skb) = *hwtstamps;
+ else
+ skb->tstamp = ktime_get_real();
+
+ __skb_complete_tx_timestamp(skb, sk, tstype, opt_stats);
+}
+EXPORT_SYMBOL_GPL(__skb_tstamp_tx);
+
+void skb_tstamp_tx(struct sk_buff *orig_skb,
+ struct skb_shared_hwtstamps *hwtstamps)
+{
+ return __skb_tstamp_tx(orig_skb, hwtstamps, orig_skb->sk,
+ SCM_TSTAMP_SND);
+}
+EXPORT_SYMBOL_GPL(skb_tstamp_tx);
+
+void skb_complete_wifi_ack(struct sk_buff *skb, bool acked)
+{
+ struct sock *sk = skb->sk;
+ struct sock_exterr_skb *serr;
+ int err = 1;
+
+ skb->wifi_acked_valid = 1;
+ skb->wifi_acked = acked;
+
+ serr = SKB_EXT_ERR(skb);
+ memset(serr, 0, sizeof(*serr));
+ serr->ee.ee_errno = ENOMSG;
+ serr->ee.ee_origin = SO_EE_ORIGIN_TXSTATUS;
+
+ /* Take a reference to prevent skb_orphan() from freeing the socket,
+ * but only if the socket refcount is not zero.
+ */
+ if (likely(refcount_inc_not_zero(&sk->sk_refcnt))) {
+ err = sock_queue_err_skb(sk, skb);
+ sock_put(sk);
+ }
+ if (err)
+ kfree_skb(skb);
+}
+EXPORT_SYMBOL_GPL(skb_complete_wifi_ack);
+
+/**
+ * skb_partial_csum_set - set up and verify partial csum values for packet
+ * @skb: the skb to set
+ * @start: the number of bytes after skb->data to start checksumming.
+ * @off: the offset from start to place the checksum.
+ *
+ * For untrusted partially-checksummed packets, we need to make sure the values
+ * for skb->csum_start and skb->csum_offset are valid so we don't oops.
+ *
+ * This function checks and sets those values and skb->ip_summed: if this
+ * returns false you should drop the packet.
+ */
+bool skb_partial_csum_set(struct sk_buff *skb, u16 start, u16 off)
+{
+ u32 csum_end = (u32)start + (u32)off + sizeof(__sum16);
+ u32 csum_start = skb_headroom(skb) + (u32)start;
+
+ if (unlikely(csum_start > U16_MAX || csum_end > skb_headlen(skb))) {
+ net_warn_ratelimited("bad partial csum: csum=%u/%u headroom=%u headlen=%u\n",
+ start, off, skb_headroom(skb), skb_headlen(skb));
+ return false;
+ }
+ skb->ip_summed = CHECKSUM_PARTIAL;
+ skb->csum_start = csum_start;
+ skb->csum_offset = off;
+ skb_set_transport_header(skb, start);
+ return true;
+}
+EXPORT_SYMBOL_GPL(skb_partial_csum_set);
+
+static int skb_maybe_pull_tail(struct sk_buff *skb, unsigned int len,
+ unsigned int max)
+{
+ if (skb_headlen(skb) >= len)
+ return 0;
+
+ /* If we need to pullup then pullup to the max, so we
+ * won't need to do it again.
+ */
+ if (max > skb->len)
+ max = skb->len;
+
+ if (__pskb_pull_tail(skb, max - skb_headlen(skb)) == NULL)
+ return -ENOMEM;
+
+ if (skb_headlen(skb) < len)
+ return -EPROTO;
+
+ return 0;
+}
+
+#define MAX_TCP_HDR_LEN (15 * 4)
+
+static __sum16 *skb_checksum_setup_ip(struct sk_buff *skb,
+ typeof(IPPROTO_IP) proto,
+ unsigned int off)
+{
+ switch (proto) {
+ int err;
+
+ case IPPROTO_TCP:
+ err = skb_maybe_pull_tail(skb, off + sizeof(struct tcphdr),
+ off + MAX_TCP_HDR_LEN);
+ if (!err && !skb_partial_csum_set(skb, off,
+ offsetof(struct tcphdr,
+ check)))
+ err = -EPROTO;
+ return err ? ERR_PTR(err) : &tcp_hdr(skb)->check;
+
+ case IPPROTO_UDP:
+ err = skb_maybe_pull_tail(skb, off + sizeof(struct udphdr),
+ off + sizeof(struct udphdr));
+ if (!err && !skb_partial_csum_set(skb, off,
+ offsetof(struct udphdr,
+ check)))
+ err = -EPROTO;
+ return err ? ERR_PTR(err) : &udp_hdr(skb)->check;
+ }
+
+ return ERR_PTR(-EPROTO);
+}
+
+/* This value should be large enough to cover a tagged ethernet header plus
+ * maximally sized IP and TCP or UDP headers.
+ */
+#define MAX_IP_HDR_LEN 128
+
+static int skb_checksum_setup_ipv4(struct sk_buff *skb, bool recalculate)
+{
+ unsigned int off;
+ bool fragment;
+ __sum16 *csum;
+ int err;
+
+ fragment = false;
+
+ err = skb_maybe_pull_tail(skb,
+ sizeof(struct iphdr),
+ MAX_IP_HDR_LEN);
+ if (err < 0)
+ goto out;
+
+ if (ip_hdr(skb)->frag_off & htons(IP_OFFSET | IP_MF))
+ fragment = true;
+
+ off = ip_hdrlen(skb);
+
+ err = -EPROTO;
+
+ if (fragment)
+ goto out;
+
+ csum = skb_checksum_setup_ip(skb, ip_hdr(skb)->protocol, off);
+ if (IS_ERR(csum))
+ return PTR_ERR(csum);
+
+ if (recalculate)
+ *csum = ~csum_tcpudp_magic(ip_hdr(skb)->saddr,
+ ip_hdr(skb)->daddr,
+ skb->len - off,
+ ip_hdr(skb)->protocol, 0);
+ err = 0;
+
+out:
+ return err;
+}
+
+/* This value should be large enough to cover a tagged ethernet header plus
+ * an IPv6 header, all options, and a maximal TCP or UDP header.
+ */
+#define MAX_IPV6_HDR_LEN 256
+
+#define OPT_HDR(type, skb, off) \
+ (type *)(skb_network_header(skb) + (off))
+
+static int skb_checksum_setup_ipv6(struct sk_buff *skb, bool recalculate)
+{
+ int err;
+ u8 nexthdr;
+ unsigned int off;
+ unsigned int len;
+ bool fragment;
+ bool done;
+ __sum16 *csum;
+
+ fragment = false;
+ done = false;
+
+ off = sizeof(struct ipv6hdr);
+
+ err = skb_maybe_pull_tail(skb, off, MAX_IPV6_HDR_LEN);
+ if (err < 0)
+ goto out;
+
+ nexthdr = ipv6_hdr(skb)->nexthdr;
+
+ len = sizeof(struct ipv6hdr) + ntohs(ipv6_hdr(skb)->payload_len);
+ while (off <= len && !done) {
+ switch (nexthdr) {
+ case IPPROTO_DSTOPTS:
+ case IPPROTO_HOPOPTS:
+ case IPPROTO_ROUTING: {
+ struct ipv6_opt_hdr *hp;
+
+ err = skb_maybe_pull_tail(skb,
+ off +
+ sizeof(struct ipv6_opt_hdr),
+ MAX_IPV6_HDR_LEN);
+ if (err < 0)
+ goto out;
+
+ hp = OPT_HDR(struct ipv6_opt_hdr, skb, off);
+ nexthdr = hp->nexthdr;
+ off += ipv6_optlen(hp);
+ break;
+ }
+ case IPPROTO_AH: {
+ struct ip_auth_hdr *hp;
+
+ err = skb_maybe_pull_tail(skb,
+ off +
+ sizeof(struct ip_auth_hdr),
+ MAX_IPV6_HDR_LEN);
+ if (err < 0)
+ goto out;
+
+ hp = OPT_HDR(struct ip_auth_hdr, skb, off);
+ nexthdr = hp->nexthdr;
+ off += ipv6_authlen(hp);
+ break;
+ }
+ case IPPROTO_FRAGMENT: {
+ struct frag_hdr *hp;
+
+ err = skb_maybe_pull_tail(skb,
+ off +
+ sizeof(struct frag_hdr),
+ MAX_IPV6_HDR_LEN);
+ if (err < 0)
+ goto out;
+
+ hp = OPT_HDR(struct frag_hdr, skb, off);
+
+ if (hp->frag_off & htons(IP6_OFFSET | IP6_MF))
+ fragment = true;
+
+ nexthdr = hp->nexthdr;
+ off += sizeof(struct frag_hdr);
+ break;
+ }
+ default:
+ done = true;
+ break;
+ }
+ }
+
+ err = -EPROTO;
+
+ if (!done || fragment)
+ goto out;
+
+ csum = skb_checksum_setup_ip(skb, nexthdr, off);
+ if (IS_ERR(csum))
+ return PTR_ERR(csum);
+
+ if (recalculate)
+ *csum = ~csum_ipv6_magic(&ipv6_hdr(skb)->saddr,
+ &ipv6_hdr(skb)->daddr,
+ skb->len - off, nexthdr, 0);
+ err = 0;
+
+out:
+ return err;
+}
+
+/**
+ * skb_checksum_setup - set up partial checksum offset
+ * @skb: the skb to set up
+ * @recalculate: if true the pseudo-header checksum will be recalculated
+ */
+int skb_checksum_setup(struct sk_buff *skb, bool recalculate)
+{
+ int err;
+
+ switch (skb->protocol) {
+ case htons(ETH_P_IP):
+ err = skb_checksum_setup_ipv4(skb, recalculate);
+ break;
+
+ case htons(ETH_P_IPV6):
+ err = skb_checksum_setup_ipv6(skb, recalculate);
+ break;
+
+ default:
+ err = -EPROTO;
+ break;
+ }
+
+ return err;
+}
+EXPORT_SYMBOL(skb_checksum_setup);
+
+/**
+ * skb_checksum_maybe_trim - maybe trims the given skb
+ * @skb: the skb to check
+ * @transport_len: the data length beyond the network header
+ *
+ * Checks whether the given skb has data beyond the given transport length.
+ * If so, returns a cloned skb trimmed to this transport length.
+ * Otherwise returns the provided skb. Returns NULL in error cases
+ * (e.g. transport_len exceeds skb length or out-of-memory).
+ *
+ * Caller needs to set the skb transport header and free any returned skb if it
+ * differs from the provided skb.
+ */
+static struct sk_buff *skb_checksum_maybe_trim(struct sk_buff *skb,
+ unsigned int transport_len)
+{
+ struct sk_buff *skb_chk;
+ unsigned int len = skb_transport_offset(skb) + transport_len;
+ int ret;
+
+ if (skb->len < len)
+ return NULL;
+ else if (skb->len == len)
+ return skb;
+
+ skb_chk = skb_clone(skb, GFP_ATOMIC);
+ if (!skb_chk)
+ return NULL;
+
+ ret = pskb_trim_rcsum(skb_chk, len);
+ if (ret) {
+ kfree_skb(skb_chk);
+ return NULL;
+ }
+
+ return skb_chk;
+}
+
+/**
+ * skb_checksum_trimmed - validate checksum of an skb
+ * @skb: the skb to check
+ * @transport_len: the data length beyond the network header
+ * @skb_chkf: checksum function to use
+ *
+ * Applies the given checksum function skb_chkf to the provided skb.
+ * Returns a checked and maybe trimmed skb. Returns NULL on error.
+ *
+ * If the skb has data beyond the given transport length, then a
+ * trimmed & cloned skb is checked and returned.
+ *
+ * Caller needs to set the skb transport header and free any returned skb if it
+ * differs from the provided skb.
+ */
+struct sk_buff *skb_checksum_trimmed(struct sk_buff *skb,
+ unsigned int transport_len,
+ __sum16(*skb_chkf)(struct sk_buff *skb))
+{
+ struct sk_buff *skb_chk;
+ unsigned int offset = skb_transport_offset(skb);
+ __sum16 ret;
+
+ skb_chk = skb_checksum_maybe_trim(skb, transport_len);
+ if (!skb_chk)
+ goto err;
+
+ if (!pskb_may_pull(skb_chk, offset))
+ goto err;
+
+ skb_pull_rcsum(skb_chk, offset);
+ ret = skb_chkf(skb_chk);
+ skb_push_rcsum(skb_chk, offset);
+
+ if (ret)
+ goto err;
+
+ return skb_chk;
+
+err:
+ if (skb_chk && skb_chk != skb)
+ kfree_skb(skb_chk);
+
+ return NULL;
+
+}
+EXPORT_SYMBOL(skb_checksum_trimmed);
+
+void __skb_warn_lro_forwarding(const struct sk_buff *skb)
+{
+ net_warn_ratelimited("%s: received packets cannot be forwarded while LRO is enabled\n",
+ skb->dev->name);
+}
+EXPORT_SYMBOL(__skb_warn_lro_forwarding);
+
+void kfree_skb_partial(struct sk_buff *skb, bool head_stolen)
+{
+ if (head_stolen) {
+ skb_release_head_state(skb);
+ kmem_cache_free(skbuff_head_cache, skb);
+ } else {
+ __kfree_skb(skb);
+ }
+}
+EXPORT_SYMBOL(kfree_skb_partial);
+
+/**
+ * skb_try_coalesce - try to merge skb to prior one
+ * @to: prior buffer
+ * @from: buffer to add
+ * @fragstolen: pointer to boolean
+ * @delta_truesize: how much more was allocated than was requested
+ */
+bool skb_try_coalesce(struct sk_buff *to, struct sk_buff *from,
+ bool *fragstolen, int *delta_truesize)
+{
+ struct skb_shared_info *to_shinfo, *from_shinfo;
+ int i, delta, len = from->len;
+
+ *fragstolen = false;
+
+ if (skb_cloned(to))
+ return false;
+
+ if (len <= skb_tailroom(to)) {
+ if (len)
+ BUG_ON(skb_copy_bits(from, 0, skb_put(to, len), len));
+ *delta_truesize = 0;
+ return true;
+ }
+
+ to_shinfo = skb_shinfo(to);
+ from_shinfo = skb_shinfo(from);
+ if (to_shinfo->frag_list || from_shinfo->frag_list)
+ return false;
+ if (skb_zcopy(to) || skb_zcopy(from))
+ return false;
+ if(skb_shinfo_is_ptr(to) || skb_shinfo_is_ptr(from))
+ return false;
+
+ if (skb_headlen(from) != 0) {
+ struct page *page;
+ unsigned int offset;
+
+ if (to_shinfo->nr_frags +
+ from_shinfo->nr_frags >= MAX_SKB_FRAGS)
+ return false;
+
+ if (skb_head_is_locked(from))
+ return false;
+
+ delta = from->truesize - SKB_DATA_ALIGN(sizeof(struct sk_buff));
+
+ page = virt_to_head_page(from->head);
+ offset = from->data - (unsigned char *)page_address(page);
+
+ skb_fill_page_desc(to, to_shinfo->nr_frags,
+ page, offset, skb_headlen(from));
+ *fragstolen = true;
+ } else {
+ if (to_shinfo->nr_frags +
+ from_shinfo->nr_frags > MAX_SKB_FRAGS)
+ return false;
+
+ delta = from->truesize - SKB_TRUESIZE(skb_end_offset(from));
+ }
+
+ WARN_ON_ONCE(delta < len);
+
+ memcpy(to_shinfo->frags + to_shinfo->nr_frags,
+ from_shinfo->frags,
+ from_shinfo->nr_frags * sizeof(skb_frag_t));
+ to_shinfo->nr_frags += from_shinfo->nr_frags;
+
+ if (!skb_cloned(from))
+ from_shinfo->nr_frags = 0;
+
+ /* if the skb is not cloned this does nothing
+ * since we set nr_frags to 0.
+ */
+ for (i = 0; i < from_shinfo->nr_frags; i++)
+ __skb_frag_ref(&from_shinfo->frags[i]);
+
+ to->truesize += delta;
+ to->len += len;
+ to->data_len += len;
+
+ *delta_truesize = delta;
+ return true;
+}
+EXPORT_SYMBOL(skb_try_coalesce);
+
+/**
+ * skb_scrub_packet - scrub an skb
+ *
+ * @skb: buffer to clean
+ * @xnet: packet is crossing netns
+ *
+ * skb_scrub_packet can be used after encapsulating or decapsulting a packet
+ * into/from a tunnel. Some information have to be cleared during these
+ * operations.
+ * skb_scrub_packet can also be used to clean a skb before injecting it in
+ * another namespace (@xnet == true). We have to clear all information in the
+ * skb that could impact namespace isolation.
+ */
+void skb_scrub_packet(struct sk_buff *skb, bool xnet)
+{
+ skb->pkt_type = PACKET_HOST;
+ skb->skb_iif = 0;
+ skb->ignore_df = 0;
+ skb_dst_drop(skb);
+ skb_ext_reset(skb);
+ nf_reset_ct(skb);
+ nf_reset_trace(skb);
+
+#ifdef CONFIG_NET_SWITCHDEV
+ skb->offload_fwd_mark = 0;
+ skb->offload_l3_fwd_mark = 0;
+#endif
+
+ if (!xnet)
+ return;
+
+ ipvs_reset(skb);
+ skb->mark = 0;
+ skb->tstamp = 0;
+}
+EXPORT_SYMBOL_GPL(skb_scrub_packet);
+
+/**
+ * skb_gso_transport_seglen - Return length of individual segments of a gso packet
+ *
+ * @skb: GSO skb
+ *
+ * skb_gso_transport_seglen is used to determine the real size of the
+ * individual segments, including Layer4 headers (TCP/UDP).
+ *
+ * The MAC/L2 or network (IP, IPv6) headers are not accounted for.
+ */
+static unsigned int skb_gso_transport_seglen(const struct sk_buff *skb)
+{
+ const struct skb_shared_info *shinfo = skb_shinfo(skb);
+ unsigned int thlen = 0;
+
+ if (skb->encapsulation) {
+ thlen = skb_inner_transport_header(skb) -
+ skb_transport_header(skb);
+
+ if (likely(shinfo->gso_type & (SKB_GSO_TCPV4 | SKB_GSO_TCPV6)))
+ thlen += inner_tcp_hdrlen(skb);
+ } else if (likely(shinfo->gso_type & (SKB_GSO_TCPV4 | SKB_GSO_TCPV6))) {
+ thlen = tcp_hdrlen(skb);
+ } else if (unlikely(skb_is_gso_sctp(skb))) {
+ thlen = sizeof(struct sctphdr);
+ } else if (shinfo->gso_type & SKB_GSO_UDP_L4) {
+ thlen = sizeof(struct udphdr);
+ }
+ /* UFO sets gso_size to the size of the fragmentation
+ * payload, i.e. the size of the L4 (UDP) header is already
+ * accounted for.
+ */
+ return thlen + shinfo->gso_size;
+}
+
+/**
+ * skb_gso_network_seglen - Return length of individual segments of a gso packet
+ *
+ * @skb: GSO skb
+ *
+ * skb_gso_network_seglen is used to determine the real size of the
+ * individual segments, including Layer3 (IP, IPv6) and L4 headers (TCP/UDP).
+ *
+ * The MAC/L2 header is not accounted for.
+ */
+static unsigned int skb_gso_network_seglen(const struct sk_buff *skb)
+{
+ unsigned int hdr_len = skb_transport_header(skb) -
+ skb_network_header(skb);
+
+ return hdr_len + skb_gso_transport_seglen(skb);
+}
+
+/**
+ * skb_gso_mac_seglen - Return length of individual segments of a gso packet
+ *
+ * @skb: GSO skb
+ *
+ * skb_gso_mac_seglen is used to determine the real size of the
+ * individual segments, including MAC/L2, Layer3 (IP, IPv6) and L4
+ * headers (TCP/UDP).
+ */
+static unsigned int skb_gso_mac_seglen(const struct sk_buff *skb)
+{
+ unsigned int hdr_len = skb_transport_header(skb) - skb_mac_header(skb);
+
+ return hdr_len + skb_gso_transport_seglen(skb);
+}
+
+/**
+ * skb_gso_size_check - check the skb size, considering GSO_BY_FRAGS
+ *
+ * There are a couple of instances where we have a GSO skb, and we
+ * want to determine what size it would be after it is segmented.
+ *
+ * We might want to check:
+ * - L3+L4+payload size (e.g. IP forwarding)
+ * - L2+L3+L4+payload size (e.g. sanity check before passing to driver)
+ *
+ * This is a helper to do that correctly considering GSO_BY_FRAGS.
+ *
+ * @skb: GSO skb
+ *
+ * @seg_len: The segmented length (from skb_gso_*_seglen). In the
+ * GSO_BY_FRAGS case this will be [header sizes + GSO_BY_FRAGS].
+ *
+ * @max_len: The maximum permissible length.
+ *
+ * Returns true if the segmented length <= max length.
+ */
+static inline bool skb_gso_size_check(const struct sk_buff *skb,
+ unsigned int seg_len,
+ unsigned int max_len) {
+ const struct skb_shared_info *shinfo = skb_shinfo(skb);
+ const struct sk_buff *iter;
+
+ if (shinfo->gso_size != GSO_BY_FRAGS)
+ return seg_len <= max_len;
+
+ /* Undo this so we can re-use header sizes */
+ seg_len -= GSO_BY_FRAGS;
+
+ skb_walk_frags(skb, iter) {
+ if (seg_len + skb_headlen(iter) > max_len)
+ return false;
+ }
+
+ return true;
+}
+
+/**
+ * skb_gso_validate_network_len - Will a split GSO skb fit into a given MTU?
+ *
+ * @skb: GSO skb
+ * @mtu: MTU to validate against
+ *
+ * skb_gso_validate_network_len validates if a given skb will fit a
+ * wanted MTU once split. It considers L3 headers, L4 headers, and the
+ * payload.
+ */
+bool skb_gso_validate_network_len(const struct sk_buff *skb, unsigned int mtu)
+{
+ return skb_gso_size_check(skb, skb_gso_network_seglen(skb), mtu);
+}
+EXPORT_SYMBOL_GPL(skb_gso_validate_network_len);
+
+/**
+ * skb_gso_validate_mac_len - Will a split GSO skb fit in a given length?
+ *
+ * @skb: GSO skb
+ * @len: length to validate against
+ *
+ * skb_gso_validate_mac_len validates if a given skb will fit a wanted
+ * length once split, including L2, L3 and L4 headers and the payload.
+ */
+bool skb_gso_validate_mac_len(const struct sk_buff *skb, unsigned int len)
+{
+ return skb_gso_size_check(skb, skb_gso_mac_seglen(skb), len);
+}
+EXPORT_SYMBOL_GPL(skb_gso_validate_mac_len);
+
+static struct sk_buff *skb_reorder_vlan_header(struct sk_buff *skb)
+{
+ int mac_len, meta_len;
+ void *meta;
+
+ if (skb_cow(skb, skb_headroom(skb)) < 0) {
+ kfree_skb(skb);
+ return NULL;
+ }
+
+ mac_len = skb->data - skb_mac_header(skb);
+ if (likely(mac_len > VLAN_HLEN + ETH_TLEN)) {
+ memmove(skb_mac_header(skb) + VLAN_HLEN, skb_mac_header(skb),
+ mac_len - VLAN_HLEN - ETH_TLEN);
+ }
+
+ meta_len = skb_metadata_len(skb);
+ if (meta_len) {
+ meta = skb_metadata_end(skb) - meta_len;
+ memmove(meta + VLAN_HLEN, meta, meta_len);
+ }
+
+ skb->mac_header += VLAN_HLEN;
+ return skb;
+}
+
+struct sk_buff *skb_vlan_untag(struct sk_buff *skb)
+{
+ struct vlan_hdr *vhdr;
+ u16 vlan_tci;
+
+ if (unlikely(skb_vlan_tag_present(skb))) {
+ /* vlan_tci is already set-up so leave this for another time */
+ return skb;
+ }
+
+ skb = skb_share_check(skb, GFP_ATOMIC);
+ if (unlikely(!skb))
+ goto err_free;
+ /* We may access the two bytes after vlan_hdr in vlan_set_encap_proto(). */
+ if (unlikely(!pskb_may_pull(skb, VLAN_HLEN + sizeof(unsigned short))))
+ goto err_free;
+
+ vhdr = (struct vlan_hdr *)skb->data;
+ vlan_tci = ntohs(vhdr->h_vlan_TCI);
+ __vlan_hwaccel_put_tag(skb, skb->protocol, vlan_tci);
+
+ skb_pull_rcsum(skb, VLAN_HLEN);
+ vlan_set_encap_proto(skb, vhdr);
+
+ skb = skb_reorder_vlan_header(skb);
+ if (unlikely(!skb))
+ goto err_free;
+
+ skb_reset_network_header(skb);
+ skb_reset_transport_header(skb);
+ skb_reset_mac_len(skb);
+
+ return skb;
+
+err_free:
+ kfree_skb(skb);
+ return NULL;
+}
+EXPORT_SYMBOL(skb_vlan_untag);
+
+int skb_ensure_writable(struct sk_buff *skb, int write_len)
+{
+ if (!pskb_may_pull(skb, write_len))
+ return -ENOMEM;
+
+ if (!skb_cloned(skb) || skb_clone_writable(skb, write_len))
+ return 0;
+
+ return pskb_expand_head(skb, 0, 0, GFP_ATOMIC);
+}
+EXPORT_SYMBOL(skb_ensure_writable);
+
+/* remove VLAN header from packet and update csum accordingly.
+ * expects a non skb_vlan_tag_present skb with a vlan tag payload
+ */
+int __skb_vlan_pop(struct sk_buff *skb, u16 *vlan_tci)
+{
+ struct vlan_hdr *vhdr;
+ int offset = skb->data - skb_mac_header(skb);
+ int err;
+
+ if (WARN_ONCE(offset,
+ "__skb_vlan_pop got skb with skb->data not at mac header (offset %d)\n",
+ offset)) {
+ return -EINVAL;
+ }
+
+ err = skb_ensure_writable(skb, VLAN_ETH_HLEN);
+ if (unlikely(err))
+ return err;
+
+ skb_postpull_rcsum(skb, skb->data + (2 * ETH_ALEN), VLAN_HLEN);
+
+ vhdr = (struct vlan_hdr *)(skb->data + ETH_HLEN);
+ *vlan_tci = ntohs(vhdr->h_vlan_TCI);
+
+ memmove(skb->data + VLAN_HLEN, skb->data, 2 * ETH_ALEN);
+ __skb_pull(skb, VLAN_HLEN);
+
+ vlan_set_encap_proto(skb, vhdr);
+ skb->mac_header += VLAN_HLEN;
+
+ if (skb_network_offset(skb) < ETH_HLEN)
+ skb_set_network_header(skb, ETH_HLEN);
+
+ skb_reset_mac_len(skb);
+
+ return err;
+}
+EXPORT_SYMBOL(__skb_vlan_pop);
+
+/* Pop a vlan tag either from hwaccel or from payload.
+ * Expects skb->data at mac header.
+ */
+int skb_vlan_pop(struct sk_buff *skb)
+{
+ u16 vlan_tci;
+ __be16 vlan_proto;
+ int err;
+
+ if (likely(skb_vlan_tag_present(skb))) {
+ __vlan_hwaccel_clear_tag(skb);
+ } else {
+ if (unlikely(!eth_type_vlan(skb->protocol)))
+ return 0;
+
+ err = __skb_vlan_pop(skb, &vlan_tci);
+ if (err)
+ return err;
+ }
+ /* move next vlan tag to hw accel tag */
+ if (likely(!eth_type_vlan(skb->protocol)))
+ return 0;
+
+ vlan_proto = skb->protocol;
+ err = __skb_vlan_pop(skb, &vlan_tci);
+ if (unlikely(err))
+ return err;
+
+ __vlan_hwaccel_put_tag(skb, vlan_proto, vlan_tci);
+ return 0;
+}
+EXPORT_SYMBOL(skb_vlan_pop);
+
+/* Push a vlan tag either into hwaccel or into payload (if hwaccel tag present).
+ * Expects skb->data at mac header.
+ */
+int skb_vlan_push(struct sk_buff *skb, __be16 vlan_proto, u16 vlan_tci)
+{
+ if (skb_vlan_tag_present(skb)) {
+ int offset = skb->data - skb_mac_header(skb);
+ int err;
+
+ if (WARN_ONCE(offset,
+ "skb_vlan_push got skb with skb->data not at mac header (offset %d)\n",
+ offset)) {
+ return -EINVAL;
+ }
+
+ err = __vlan_insert_tag(skb, skb->vlan_proto,
+ skb_vlan_tag_get(skb));
+ if (err)
+ return err;
+
+ skb->protocol = skb->vlan_proto;
+ skb->mac_len += VLAN_HLEN;
+
+ skb_postpush_rcsum(skb, skb->data + (2 * ETH_ALEN), VLAN_HLEN);
+ }
+ __vlan_hwaccel_put_tag(skb, vlan_proto, vlan_tci);
+ return 0;
+}
+EXPORT_SYMBOL(skb_vlan_push);
+
+/* Update the ethertype of hdr and the skb csum value if required. */
+static void skb_mod_eth_type(struct sk_buff *skb, struct ethhdr *hdr,
+ __be16 ethertype)
+{
+ if (skb->ip_summed == CHECKSUM_COMPLETE) {
+ __be16 diff[] = { ~hdr->h_proto, ethertype };
+
+ skb->csum = csum_partial((char *)diff, sizeof(diff), skb->csum);
+ }
+
+ hdr->h_proto = ethertype;
+}
+
+/**
+ * skb_mpls_push() - push a new MPLS header after the mac header
+ *
+ * @skb: buffer
+ * @mpls_lse: MPLS label stack entry to push
+ * @mpls_proto: ethertype of the new MPLS header (expects 0x8847 or 0x8848)
+ * @mac_len: length of the MAC header
+ *
+ * Expects skb->data at mac header.
+ *
+ * Returns 0 on success, -errno otherwise.
+ */
+int skb_mpls_push(struct sk_buff *skb, __be32 mpls_lse, __be16 mpls_proto,
+ int mac_len, bool ethernet)
+{
+ struct mpls_shim_hdr *lse;
+ int err;
+
+ if (unlikely(!eth_p_mpls(mpls_proto)))
+ return -EINVAL;
+
+ /* Networking stack does not allow simultaneous Tunnel and MPLS GSO. */
+ if (skb->encapsulation)
+ return -EINVAL;
+
+ err = skb_cow_head(skb, MPLS_HLEN);
+ if (unlikely(err))
+ return err;
+
+ if (!skb->inner_protocol) {
+ skb_set_inner_network_header(skb, mac_len);
+ skb_set_inner_protocol(skb, skb->protocol);
+ }
+
+ skb_push(skb, MPLS_HLEN);
+ memmove(skb_mac_header(skb) - MPLS_HLEN, skb_mac_header(skb),
+ mac_len);
+ skb_reset_mac_header(skb);
+ skb_set_network_header(skb, mac_len);
+
+ lse = mpls_hdr(skb);
+ lse->label_stack_entry = mpls_lse;
+ skb_postpush_rcsum(skb, lse, MPLS_HLEN);
+
+ if (ethernet && mac_len >= ETH_HLEN)
+ skb_mod_eth_type(skb, eth_hdr(skb), mpls_proto);
+ skb->protocol = mpls_proto;
+
+ return 0;
+}
+EXPORT_SYMBOL_GPL(skb_mpls_push);
+
+/**
+ * skb_mpls_pop() - pop the outermost MPLS header
+ *
+ * @skb: buffer
+ * @next_proto: ethertype of header after popped MPLS header
+ * @mac_len: length of the MAC header
+ * @ethernet: flag to indicate if ethernet header is present in packet
+ *
+ * Expects skb->data at mac header.
+ *
+ * Returns 0 on success, -errno otherwise.
+ */
+int skb_mpls_pop(struct sk_buff *skb, __be16 next_proto, int mac_len,
+ bool ethernet)
+{
+ int err;
+
+ if (unlikely(!eth_p_mpls(skb->protocol)))
+ return 0;
+
+ err = skb_ensure_writable(skb, mac_len + MPLS_HLEN);
+ if (unlikely(err))
+ return err;
+
+ skb_postpull_rcsum(skb, mpls_hdr(skb), MPLS_HLEN);
+ memmove(skb_mac_header(skb) + MPLS_HLEN, skb_mac_header(skb),
+ mac_len);
+
+ __skb_pull(skb, MPLS_HLEN);
+ skb_reset_mac_header(skb);
+ skb_set_network_header(skb, mac_len);
+
+ if (ethernet && mac_len >= ETH_HLEN) {
+ struct ethhdr *hdr;
+
+ /* use mpls_hdr() to get ethertype to account for VLANs. */
+ hdr = (struct ethhdr *)((void *)mpls_hdr(skb) - ETH_HLEN);
+ skb_mod_eth_type(skb, hdr, next_proto);
+ }
+ skb->protocol = next_proto;
+
+ return 0;
+}
+EXPORT_SYMBOL_GPL(skb_mpls_pop);
+
+/**
+ * skb_mpls_update_lse() - modify outermost MPLS header and update csum
+ *
+ * @skb: buffer
+ * @mpls_lse: new MPLS label stack entry to update to
+ *
+ * Expects skb->data at mac header.
+ *
+ * Returns 0 on success, -errno otherwise.
+ */
+int skb_mpls_update_lse(struct sk_buff *skb, __be32 mpls_lse)
+{
+ int err;
+
+ if (unlikely(!eth_p_mpls(skb->protocol)))
+ return -EINVAL;
+
+ err = skb_ensure_writable(skb, skb->mac_len + MPLS_HLEN);
+ if (unlikely(err))
+ return err;
+
+ if (skb->ip_summed == CHECKSUM_COMPLETE) {
+ __be32 diff[] = { ~mpls_hdr(skb)->label_stack_entry, mpls_lse };
+
+ skb->csum = csum_partial((char *)diff, sizeof(diff), skb->csum);
+ }
+
+ mpls_hdr(skb)->label_stack_entry = mpls_lse;
+
+ return 0;
+}
+EXPORT_SYMBOL_GPL(skb_mpls_update_lse);
+
+/**
+ * skb_mpls_dec_ttl() - decrement the TTL of the outermost MPLS header
+ *
+ * @skb: buffer
+ *
+ * Expects skb->data at mac header.
+ *
+ * Returns 0 on success, -errno otherwise.
+ */
+int skb_mpls_dec_ttl(struct sk_buff *skb)
+{
+ u32 lse;
+ u8 ttl;
+
+ if (unlikely(!eth_p_mpls(skb->protocol)))
+ return -EINVAL;
+
+ if (!pskb_may_pull(skb, skb_network_offset(skb) + MPLS_HLEN))
+ return -ENOMEM;
+
+ lse = be32_to_cpu(mpls_hdr(skb)->label_stack_entry);
+ ttl = (lse & MPLS_LS_TTL_MASK) >> MPLS_LS_TTL_SHIFT;
+ if (!--ttl)
+ return -EINVAL;
+
+ lse &= ~MPLS_LS_TTL_MASK;
+ lse |= ttl << MPLS_LS_TTL_SHIFT;
+
+ return skb_mpls_update_lse(skb, cpu_to_be32(lse));
+}
+EXPORT_SYMBOL_GPL(skb_mpls_dec_ttl);
+
+/**
+ * alloc_skb_with_frags - allocate skb with page frags
+ *
+ * @header_len: size of linear part
+ * @data_len: needed length in frags
+ * @max_page_order: max page order desired.
+ * @errcode: pointer to error code if any
+ * @gfp_mask: allocation mask
+ *
+ * This can be used to allocate a paged skb, given a maximal order for frags.
+ */
+struct sk_buff *alloc_skb_with_frags(unsigned long header_len,
+ unsigned long data_len,
+ int max_page_order,
+ int *errcode,
+ gfp_t gfp_mask)
+{
+ int npages = (data_len + (PAGE_SIZE - 1)) >> PAGE_SHIFT;
+ unsigned long chunk;
+ struct sk_buff *skb;
+ struct page *page;
+ int i;
+
+ *errcode = -EMSGSIZE;
+ /* Note this test could be relaxed, if we succeed to allocate
+ * high order pages...
+ */
+ if (npages > MAX_SKB_FRAGS)
+ return NULL;
+
+ *errcode = -ENOBUFS;
+ skb = alloc_skb(header_len, gfp_mask);
+ if (!skb)
+ return NULL;
+
+ skb->truesize += npages << PAGE_SHIFT;
+
+ for (i = 0; npages > 0; i++) {
+ int order = max_page_order;
+
+ while (order) {
+ if (npages >= 1 << order) {
+ page = alloc_pages((gfp_mask & ~__GFP_DIRECT_RECLAIM) |
+ __GFP_COMP |
+ __GFP_NOWARN,
+ order);
+ if (page)
+ goto fill_page;
+ /* Do not retry other high order allocations */
+ order = 1;
+ max_page_order = 0;
+ }
+ order--;
+ }
+ page = alloc_page(gfp_mask);
+ if (!page)
+ goto failure;
+fill_page:
+ chunk = min_t(unsigned long, data_len,
+ PAGE_SIZE << order);
+ skb_fill_page_desc(skb, i, page, 0, chunk);
+ data_len -= chunk;
+ npages -= 1 << order;
+ }
+ return skb;
+
+failure:
+ kfree_skb(skb);
+ return NULL;
+}
+EXPORT_SYMBOL(alloc_skb_with_frags);
+
+/* carve out the first off bytes from skb when off < headlen */
+static int pskb_carve_inside_header(struct sk_buff *skb, const u32 off,
+ const int headlen, gfp_t gfp_mask)
+{
+ int i;
+ int size = skb_end_offset(skb);
+ int new_hlen = headlen - off;
+ u8 *data;
+
+ size = SKB_DATA_ALIGN(size);
+
+ if (skb_pfmemalloc(skb))
+ gfp_mask |= __GFP_MEMALLOC;
+ data = kmalloc_reserve(size +
+ SKB_DATA_ALIGN(sizeof(struct skb_shared_info)),
+ gfp_mask, NUMA_NO_NODE, NULL);
+ if (!data)
+ return -ENOMEM;
+
+ size = SKB_WITH_OVERHEAD(ksize(data));
+
+ /* Copy real data, and all frags */
+ skb_copy_from_linear_data_offset(skb, off, data, new_hlen);
+ skb->len -= off;
+
+ memcpy((struct skb_shared_info *)(data + size),
+ skb_shinfo(skb),
+ offsetof(struct skb_shared_info,
+ frags[skb_shinfo(skb)->nr_frags]));
+ if (skb_cloned(skb)) {
+ /* drop the old head gracefully */
+ if (skb_orphan_frags(skb, gfp_mask)) {
+ kfree(data);
+ return -ENOMEM;
+ }
+ for (i = 0; i < skb_shinfo(skb)->nr_frags; i++)
+ skb_frag_ref(skb, i);
+ if (skb_has_frag_list(skb))
+ skb_clone_fraglist(skb);
+ skb_release_data(skb);
+ } else {
+ /* we can reuse existing recount- all we did was
+ * relocate values
+ */
+ skb_free_head(skb);
+ }
+
+ skb->head = data;
+ skb->data = data;
+ skb->head_frag = 0;
+#ifdef NET_SKBUFF_DATA_USES_OFFSET
+ skb->end = size;
+#else
+ skb->end = skb->head + size;
+#endif
+ skb_set_tail_pointer(skb, skb_headlen(skb));
+ skb_headers_offset_update(skb, 0);
+ skb->cloned = 0;
+ skb->hdr_len = 0;
+ skb->nohdr = 0;
+ skb->shared_info_ptr = NULL;
+ atomic_set(&skb_shinfo(skb)->dataref, 1);
+
+ return 0;
+}
+
+static int pskb_carve(struct sk_buff *skb, const u32 off, gfp_t gfp);
+
+/* carve out the first eat bytes from skb's frag_list. May recurse into
+ * pskb_carve()
+ */
+static int pskb_carve_frag_list(struct sk_buff *skb,
+ struct skb_shared_info *shinfo, int eat,
+ gfp_t gfp_mask)
+{
+ struct sk_buff *list = shinfo->frag_list;
+ struct sk_buff *clone = NULL;
+ struct sk_buff *insp = NULL;
+
+ do {
+ if (!list) {
+ pr_err("Not enough bytes to eat. Want %d\n", eat);
+ return -EFAULT;
+ }
+ if (list->len <= eat) {
+ /* Eaten as whole. */
+ eat -= list->len;
+ list = list->next;
+ insp = list;
+ } else {
+ /* Eaten partially. */
+ if (skb_shared(list)) {
+ clone = skb_clone(list, gfp_mask);
+ if (!clone)
+ return -ENOMEM;
+ insp = list->next;
+ list = clone;
+ } else {
+ /* This may be pulled without problems. */
+ insp = list;
+ }
+ if (pskb_carve(list, eat, gfp_mask) < 0) {
+ kfree_skb(clone);
+ return -ENOMEM;
+ }
+ break;
+ }
+ } while (eat);
+
+ /* Free pulled out fragments. */
+ while ((list = shinfo->frag_list) != insp) {
+ shinfo->frag_list = list->next;
+ consume_skb(list);
+ }
+ /* And insert new clone at head. */
+ if (clone) {
+ clone->next = list;
+ shinfo->frag_list = clone;
+ }
+ return 0;
+}
+
+/* carve off first len bytes from skb. Split line (off) is in the
+ * non-linear part of skb
+ */
+static int pskb_carve_inside_nonlinear(struct sk_buff *skb, const u32 off,
+ int pos, gfp_t gfp_mask)
+{
+ int i, k = 0;
+ int size = skb_end_offset(skb);
+ u8 *data;
+ const int nfrags = skb_shinfo(skb)->nr_frags;
+ struct skb_shared_info *shinfo;
+
+ size = SKB_DATA_ALIGN(size);
+
+ if (skb_pfmemalloc(skb))
+ gfp_mask |= __GFP_MEMALLOC;
+ data = kmalloc_reserve(size +
+ SKB_DATA_ALIGN(sizeof(struct skb_shared_info)),
+ gfp_mask, NUMA_NO_NODE, NULL);
+ if (!data)
+ return -ENOMEM;
+
+ size = SKB_WITH_OVERHEAD(ksize(data));
+
+ memcpy((struct skb_shared_info *)(data + size),
+ skb_shinfo(skb), offsetof(struct skb_shared_info,
+ frags[skb_shinfo(skb)->nr_frags]));
+ if (skb_orphan_frags(skb, gfp_mask)) {
+ kfree(data);
+ return -ENOMEM;
+ }
+ shinfo = (struct skb_shared_info *)(data + size);
+ for (i = 0; i < nfrags; i++) {
+ int fsize = skb_frag_size(&skb_shinfo(skb)->frags[i]);
+
+ if (pos + fsize > off) {
+ shinfo->frags[k] = skb_shinfo(skb)->frags[i];
+
+ if (pos < off) {
+ /* Split frag.
+ * We have two variants in this case:
+ * 1. Move all the frag to the second
+ * part, if it is possible. F.e.
+ * this approach is mandatory for TUX,
+ * where splitting is expensive.
+ * 2. Split is accurately. We make this.
+ */
+ skb_frag_off_add(&shinfo->frags[0], off - pos);
+ skb_frag_size_sub(&shinfo->frags[0], off - pos);
+ }
+ skb_frag_ref(skb, i);
+ k++;
+ }
+ pos += fsize;
+ }
+ shinfo->nr_frags = k;
+ if (skb_has_frag_list(skb))
+ skb_clone_fraglist(skb);
+
+ /* split line is in frag list */
+ if (k == 0 && pskb_carve_frag_list(skb, shinfo, off - pos, gfp_mask)) {
+ /* skb_frag_unref() is not needed here as shinfo->nr_frags = 0. */
+ if (skb_has_frag_list(skb))
+ kfree_skb_list(skb_shinfo(skb)->frag_list);
+ kfree(data);
+ return -ENOMEM;
+ }
+ skb_release_data(skb);
+
+ skb->head = data;
+ skb->head_frag = 0;
+ skb->data = data;
+#ifdef NET_SKBUFF_DATA_USES_OFFSET
+ skb->end = size;
+#else
+ skb->end = skb->head + size;
+#endif
+ skb_reset_tail_pointer(skb);
+ skb_headers_offset_update(skb, 0);
+ skb->cloned = 0;
+ skb->hdr_len = 0;
+ skb->nohdr = 0;
+ skb->len -= off;
+ skb->data_len = skb->len;
+ skb->shared_info_ptr = NULL;
+ atomic_set(&skb_shinfo(skb)->dataref, 1);
+ return 0;
+}
+
+/* remove len bytes from the beginning of the skb */
+static int pskb_carve(struct sk_buff *skb, const u32 len, gfp_t gfp)
+{
+ int headlen = skb_headlen(skb);
+
+ if (len < headlen)
+ return pskb_carve_inside_header(skb, len, headlen, gfp);
+ else
+ return pskb_carve_inside_nonlinear(skb, len, headlen, gfp);
+}
+
+/* Extract to_copy bytes starting at off from skb, and return this in
+ * a new skb
+ */
+struct sk_buff *pskb_extract(struct sk_buff *skb, int off,
+ int to_copy, gfp_t gfp)
+{
+ struct sk_buff *clone = skb_clone(skb, gfp);
+
+ if (!clone)
+ return NULL;
+
+ if (pskb_carve(clone, off, gfp) < 0 ||
+ pskb_trim(clone, to_copy)) {
+ kfree_skb(clone);
+ return NULL;
+ }
+ return clone;
+}
+EXPORT_SYMBOL(pskb_extract);
+
+/**
+ * skb_condense - try to get rid of fragments/frag_list if possible
+ * @skb: buffer
+ *
+ * Can be used to save memory before skb is added to a busy queue.
+ * If packet has bytes in frags and enough tail room in skb->head,
+ * pull all of them, so that we can free the frags right now and adjust
+ * truesize.
+ * Notes:
+ * We do not reallocate skb->head thus can not fail.
+ * Caller must re-evaluate skb->truesize if needed.
+ */
+void skb_condense(struct sk_buff *skb)
+{
+ if (skb->data_len) {
+ if (skb->data_len > skb->end - skb->tail ||
+ skb_cloned(skb))
+ return;
+
+ /* Nice, we can free page frag(s) right now */
+ __pskb_pull_tail(skb, skb->data_len);
+ }
+ /* At this point, skb->truesize might be over estimated,
+ * because skb had a fragment, and fragments do not tell
+ * their truesize.
+ * When we pulled its content into skb->head, fragment
+ * was freed, but __pskb_pull_tail() could not possibly
+ * adjust skb->truesize, not knowing the frag truesize.
+ */
+ skb->truesize = SKB_TRUESIZE(skb_end_offset(skb));
+}
+
+#ifdef CONFIG_SKB_EXTENSIONS
+static void *skb_ext_get_ptr(struct skb_ext *ext, enum skb_ext_id id)
+{
+ return (void *)ext + (ext->offset[id] * SKB_EXT_ALIGN_VALUE);
+}
+
+static struct skb_ext *skb_ext_alloc(void)
+{
+ struct skb_ext *new = kmem_cache_alloc(skbuff_ext_cache, GFP_ATOMIC);
+
+ if (new) {
+ memset(new->offset, 0, sizeof(new->offset));
+ refcount_set(&new->refcnt, 1);
+ }
+
+ return new;
+}
+
+static struct skb_ext *skb_ext_maybe_cow(struct skb_ext *old,
+ unsigned int old_active)
+{
+ struct skb_ext *new;
+
+ if (refcount_read(&old->refcnt) == 1)
+ return old;
+
+ new = kmem_cache_alloc(skbuff_ext_cache, GFP_ATOMIC);
+ if (!new)
+ return NULL;
+
+ memcpy(new, old, old->chunks * SKB_EXT_ALIGN_VALUE);
+ refcount_set(&new->refcnt, 1);
+
+#ifdef CONFIG_XFRM
+ if (old_active & (1 << SKB_EXT_SEC_PATH)) {
+ struct sec_path *sp = skb_ext_get_ptr(old, SKB_EXT_SEC_PATH);
+ unsigned int i;
+
+ for (i = 0; i < sp->len; i++)
+ xfrm_state_hold(sp->xvec[i]);
+ }
+#endif
+ __skb_ext_put(old);
+ return new;
+}
+
+/**
+ * skb_ext_add - allocate space for given extension, COW if needed
+ * @skb: buffer
+ * @id: extension to allocate space for
+ *
+ * Allocates enough space for the given extension.
+ * If the extension is already present, a pointer to that extension
+ * is returned.
+ *
+ * If the skb was cloned, COW applies and the returned memory can be
+ * modified without changing the extension space of clones buffers.
+ *
+ * Returns pointer to the extension or NULL on allocation failure.
+ */
+void *skb_ext_add(struct sk_buff *skb, enum skb_ext_id id)
+{
+ struct skb_ext *new, *old = NULL;
+ unsigned int newlen, newoff;
+
+ if (skb->active_extensions) {
+ old = skb->extensions;
+
+ new = skb_ext_maybe_cow(old, skb->active_extensions);
+ if (!new)
+ return NULL;
+
+ if (__skb_ext_exist(new, id))
+ goto set_active;
+
+ newoff = new->chunks;
+ } else {
+ newoff = SKB_EXT_CHUNKSIZEOF(*new);
+
+ new = skb_ext_alloc();
+ if (!new)
+ return NULL;
+ }
+
+ newlen = newoff + skb_ext_type_len[id];
+ new->chunks = newlen;
+ new->offset[id] = newoff;
+set_active:
+ skb->extensions = new;
+ skb->active_extensions |= 1 << id;
+ return skb_ext_get_ptr(new, id);
+}
+EXPORT_SYMBOL(skb_ext_add);
+
+#ifdef CONFIG_XFRM
+static void skb_ext_put_sp(struct sec_path *sp)
+{
+ unsigned int i;
+
+ for (i = 0; i < sp->len; i++)
+ xfrm_state_put(sp->xvec[i]);
+}
+#endif
+
+void __skb_ext_del(struct sk_buff *skb, enum skb_ext_id id)
+{
+ struct skb_ext *ext = skb->extensions;
+
+ skb->active_extensions &= ~(1 << id);
+ if (skb->active_extensions == 0) {
+ skb->extensions = NULL;
+ __skb_ext_put(ext);
+#ifdef CONFIG_XFRM
+ } else if (id == SKB_EXT_SEC_PATH &&
+ refcount_read(&ext->refcnt) == 1) {
+ struct sec_path *sp = skb_ext_get_ptr(ext, SKB_EXT_SEC_PATH);
+
+ skb_ext_put_sp(sp);
+ sp->len = 0;
+#endif
+ }
+}
+EXPORT_SYMBOL(__skb_ext_del);
+
+void __skb_ext_put(struct skb_ext *ext)
+{
+ /* If this is last clone, nothing can increment
+ * it after check passes. Avoids one atomic op.
+ */
+ if (refcount_read(&ext->refcnt) == 1)
+ goto free_now;
+
+ if (!refcount_dec_and_test(&ext->refcnt))
+ return;
+free_now:
+#ifdef CONFIG_XFRM
+ if (__skb_ext_exist(ext, SKB_EXT_SEC_PATH))
+ skb_ext_put_sp(skb_ext_get_ptr(ext, SKB_EXT_SEC_PATH));
+#endif
+
+ kmem_cache_free(skbuff_ext_cache, ext);
+}
+EXPORT_SYMBOL(__skb_ext_put);
+#endif /* CONFIG_SKB_EXTENSIONS */