[Feature] add GA346 baseline version
Change-Id: Ic62933698569507dcf98240cdf5d9931ae34348f
diff --git a/src/kernel/linux/v4.19/net/ipv6/syncookies.c b/src/kernel/linux/v4.19/net/ipv6/syncookies.c
new file mode 100644
index 0000000..e997141
--- /dev/null
+++ b/src/kernel/linux/v4.19/net/ipv6/syncookies.c
@@ -0,0 +1,263 @@
+/*
+ * IPv6 Syncookies implementation for the Linux kernel
+ *
+ * Authors:
+ * Glenn Griffin <ggriffin.kernel@gmail.com>
+ *
+ * Based on IPv4 implementation by Andi Kleen
+ * linux/net/ipv4/syncookies.c
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version
+ * 2 of the License, or (at your option) any later version.
+ *
+ */
+
+#include <linux/tcp.h>
+#include <linux/random.h>
+#include <linux/siphash.h>
+#include <linux/kernel.h>
+#include <net/secure_seq.h>
+#include <net/ipv6.h>
+#include <net/tcp.h>
+
+#define COOKIEBITS 24 /* Upper bits store count */
+#define COOKIEMASK (((__u32)1 << COOKIEBITS) - 1)
+
+static siphash_key_t syncookie6_secret[2] __read_mostly;
+
+/* RFC 2460, Section 8.3:
+ * [ipv6 tcp] MSS must be computed as the maximum packet size minus 60 [..]
+ *
+ * Due to IPV6_MIN_MTU=1280 the lowest possible MSS is 1220, which allows
+ * using higher values than ipv4 tcp syncookies.
+ * The other values are chosen based on ethernet (1500 and 9k MTU), plus
+ * one that accounts for common encap (PPPoe) overhead. Table must be sorted.
+ */
+static __u16 const msstab[] = {
+ 1280 - 60, /* IPV6_MIN_MTU - 60 */
+ 1480 - 60,
+ 1500 - 60,
+ 9000 - 60,
+};
+
+static u32 cookie_hash(const struct in6_addr *saddr,
+ const struct in6_addr *daddr,
+ __be16 sport, __be16 dport, u32 count, int c)
+{
+ const struct {
+ struct in6_addr saddr;
+ struct in6_addr daddr;
+ u32 count;
+ __be16 sport;
+ __be16 dport;
+ } __aligned(SIPHASH_ALIGNMENT) combined = {
+ .saddr = *saddr,
+ .daddr = *daddr,
+ .count = count,
+ .sport = sport,
+ .dport = dport
+ };
+
+ net_get_random_once(syncookie6_secret, sizeof(syncookie6_secret));
+ return siphash(&combined, offsetofend(typeof(combined), dport),
+ &syncookie6_secret[c]);
+}
+
+static __u32 secure_tcp_syn_cookie(const struct in6_addr *saddr,
+ const struct in6_addr *daddr,
+ __be16 sport, __be16 dport, __u32 sseq,
+ __u32 data)
+{
+ u32 count = tcp_cookie_time();
+ return (cookie_hash(saddr, daddr, sport, dport, 0, 0) +
+ sseq + (count << COOKIEBITS) +
+ ((cookie_hash(saddr, daddr, sport, dport, count, 1) + data)
+ & COOKIEMASK));
+}
+
+static __u32 check_tcp_syn_cookie(__u32 cookie, const struct in6_addr *saddr,
+ const struct in6_addr *daddr, __be16 sport,
+ __be16 dport, __u32 sseq)
+{
+ __u32 diff, count = tcp_cookie_time();
+
+ cookie -= cookie_hash(saddr, daddr, sport, dport, 0, 0) + sseq;
+
+ diff = (count - (cookie >> COOKIEBITS)) & ((__u32) -1 >> COOKIEBITS);
+ if (diff >= MAX_SYNCOOKIE_AGE)
+ return (__u32)-1;
+
+ return (cookie -
+ cookie_hash(saddr, daddr, sport, dport, count - diff, 1))
+ & COOKIEMASK;
+}
+
+u32 __cookie_v6_init_sequence(const struct ipv6hdr *iph,
+ const struct tcphdr *th, __u16 *mssp)
+{
+ int mssind;
+ const __u16 mss = *mssp;
+
+ for (mssind = ARRAY_SIZE(msstab) - 1; mssind ; mssind--)
+ if (mss >= msstab[mssind])
+ break;
+
+ *mssp = msstab[mssind];
+
+ return secure_tcp_syn_cookie(&iph->saddr, &iph->daddr, th->source,
+ th->dest, ntohl(th->seq), mssind);
+}
+EXPORT_SYMBOL_GPL(__cookie_v6_init_sequence);
+
+__u32 cookie_v6_init_sequence(const struct sk_buff *skb, __u16 *mssp)
+{
+ const struct ipv6hdr *iph = ipv6_hdr(skb);
+ const struct tcphdr *th = tcp_hdr(skb);
+
+ return __cookie_v6_init_sequence(iph, th, mssp);
+}
+
+int __cookie_v6_check(const struct ipv6hdr *iph, const struct tcphdr *th,
+ __u32 cookie)
+{
+ __u32 seq = ntohl(th->seq) - 1;
+ __u32 mssind = check_tcp_syn_cookie(cookie, &iph->saddr, &iph->daddr,
+ th->source, th->dest, seq);
+
+ return mssind < ARRAY_SIZE(msstab) ? msstab[mssind] : 0;
+}
+EXPORT_SYMBOL_GPL(__cookie_v6_check);
+
+struct sock *cookie_v6_check(struct sock *sk, struct sk_buff *skb)
+{
+ struct tcp_options_received tcp_opt;
+ struct inet_request_sock *ireq;
+ struct tcp_request_sock *treq;
+ struct ipv6_pinfo *np = inet6_sk(sk);
+ struct tcp_sock *tp = tcp_sk(sk);
+ const struct tcphdr *th = tcp_hdr(skb);
+ __u32 cookie = ntohl(th->ack_seq) - 1;
+ struct sock *ret = sk;
+ struct request_sock *req;
+ int mss;
+ struct dst_entry *dst;
+ __u8 rcv_wscale;
+ u32 tsoff = 0;
+
+ if (!sock_net(sk)->ipv4.sysctl_tcp_syncookies || !th->ack || th->rst)
+ goto out;
+
+ if (tcp_synq_no_recent_overflow(sk))
+ goto out;
+
+ mss = __cookie_v6_check(ipv6_hdr(skb), th, cookie);
+ if (mss == 0) {
+ __NET_INC_STATS(sock_net(sk), LINUX_MIB_SYNCOOKIESFAILED);
+ goto out;
+ }
+
+ __NET_INC_STATS(sock_net(sk), LINUX_MIB_SYNCOOKIESRECV);
+
+ /* check for timestamp cookie support */
+ memset(&tcp_opt, 0, sizeof(tcp_opt));
+ tcp_parse_options(sock_net(sk), skb, &tcp_opt, 0, NULL);
+
+ if (tcp_opt.saw_tstamp && tcp_opt.rcv_tsecr) {
+ tsoff = secure_tcpv6_ts_off(sock_net(sk),
+ ipv6_hdr(skb)->daddr.s6_addr32,
+ ipv6_hdr(skb)->saddr.s6_addr32);
+ tcp_opt.rcv_tsecr -= tsoff;
+ }
+
+ if (!cookie_timestamp_decode(sock_net(sk), &tcp_opt))
+ goto out;
+
+ ret = NULL;
+ req = inet_reqsk_alloc(&tcp6_request_sock_ops, sk, false);
+ if (!req)
+ goto out;
+
+ ireq = inet_rsk(req);
+ treq = tcp_rsk(req);
+ treq->tfo_listener = false;
+
+ if (security_inet_conn_request(sk, skb, req))
+ goto out_free;
+
+ req->mss = mss;
+ ireq->ir_rmt_port = th->source;
+ ireq->ir_num = ntohs(th->dest);
+ ireq->ir_v6_rmt_addr = ipv6_hdr(skb)->saddr;
+ ireq->ir_v6_loc_addr = ipv6_hdr(skb)->daddr;
+ if (ipv6_opt_accepted(sk, skb, &TCP_SKB_CB(skb)->header.h6) ||
+ np->rxopt.bits.rxinfo || np->rxopt.bits.rxoinfo ||
+ np->rxopt.bits.rxhlim || np->rxopt.bits.rxohlim) {
+ refcount_inc(&skb->users);
+ ireq->pktopts = skb;
+ }
+
+ ireq->ir_iif = inet_request_bound_dev_if(sk, skb);
+ /* So that link locals have meaning */
+ if (!sk->sk_bound_dev_if &&
+ ipv6_addr_type(&ireq->ir_v6_rmt_addr) & IPV6_ADDR_LINKLOCAL)
+ ireq->ir_iif = tcp_v6_iif(skb);
+
+ ireq->ir_mark = inet_request_mark(sk, skb);
+
+ req->num_retrans = 0;
+ ireq->snd_wscale = tcp_opt.snd_wscale;
+ ireq->sack_ok = tcp_opt.sack_ok;
+ ireq->wscale_ok = tcp_opt.wscale_ok;
+ ireq->tstamp_ok = tcp_opt.saw_tstamp;
+ req->ts_recent = tcp_opt.saw_tstamp ? tcp_opt.rcv_tsval : 0;
+ treq->snt_synack = 0;
+ treq->rcv_isn = ntohl(th->seq) - 1;
+ treq->snt_isn = cookie;
+ treq->ts_off = 0;
+ treq->txhash = net_tx_rndhash();
+ if (IS_ENABLED(CONFIG_SMC))
+ ireq->smc_ok = 0;
+
+ /*
+ * We need to lookup the dst_entry to get the correct window size.
+ * This is taken from tcp_v6_syn_recv_sock. Somebody please enlighten
+ * me if there is a preferred way.
+ */
+ {
+ struct in6_addr *final_p, final;
+ struct flowi6 fl6;
+ memset(&fl6, 0, sizeof(fl6));
+ fl6.flowi6_proto = IPPROTO_TCP;
+ fl6.daddr = ireq->ir_v6_rmt_addr;
+ final_p = fl6_update_dst(&fl6, rcu_dereference(np->opt), &final);
+ fl6.saddr = ireq->ir_v6_loc_addr;
+ fl6.flowi6_oif = ireq->ir_iif;
+ fl6.flowi6_mark = ireq->ir_mark;
+ fl6.fl6_dport = ireq->ir_rmt_port;
+ fl6.fl6_sport = inet_sk(sk)->inet_sport;
+ fl6.flowi6_uid = sk->sk_uid;
+ security_req_classify_flow(req, flowi6_to_flowi(&fl6));
+
+ dst = ip6_dst_lookup_flow(sk, &fl6, final_p);
+ if (IS_ERR(dst))
+ goto out_free;
+ }
+
+ req->rsk_window_clamp = tp->window_clamp ? :dst_metric(dst, RTAX_WINDOW);
+ tcp_select_initial_window(sk, tcp_full_space(sk), req->mss,
+ &req->rsk_rcv_wnd, &req->rsk_window_clamp,
+ ireq->wscale_ok, &rcv_wscale,
+ dst_metric(dst, RTAX_INITRWND));
+
+ ireq->rcv_wscale = rcv_wscale;
+ ireq->ecn_ok = cookie_ecn_ok(&tcp_opt, sock_net(sk), dst);
+
+ ret = tcp_get_cookie_sock(sk, skb, req, dst, tsoff);
+out:
+ return ret;
+out_free:
+ reqsk_free(req);
+ return NULL;
+}