lh | 9ed821d | 2023-04-07 01:36:19 -0700 | [diff] [blame] | 1 | /* Shared library add-on to iptables for ECN matching |
| 2 | * |
| 3 | * (C) 2002 by Harald Welte <laforge@gnumonks.org> |
| 4 | * |
| 5 | * This program is distributed under the terms of GNU GPL v2, 1991 |
| 6 | * |
| 7 | * libipt_ecn.c borrowed heavily from libipt_dscp.c |
| 8 | * |
| 9 | */ |
| 10 | #include <stdio.h> |
| 11 | #include <string.h> |
| 12 | #include <stdlib.h> |
| 13 | #include <getopt.h> |
| 14 | |
| 15 | #include <xtables.h> |
| 16 | #include <linux/netfilter_ipv4/ipt_ecn.h> |
| 17 | |
| 18 | static void ecn_help(void) |
| 19 | { |
| 20 | printf( |
| 21 | "ECN match options\n" |
| 22 | "[!] --ecn-tcp-cwr Match CWR bit of TCP header\n" |
| 23 | "[!] --ecn-tcp-ece Match ECE bit of TCP header\n" |
| 24 | "[!] --ecn-ip-ect [0..3] Match ECN codepoint in IPv4 header\n"); |
| 25 | } |
| 26 | |
| 27 | static const struct option ecn_opts[] = { |
| 28 | { .name = "ecn-tcp-cwr", .has_arg = 0, .val = 'F' }, |
| 29 | { .name = "ecn-tcp-ece", .has_arg = 0, .val = 'G' }, |
| 30 | { .name = "ecn-ip-ect", .has_arg = 1, .val = 'H' }, |
| 31 | { .name = NULL } |
| 32 | }; |
| 33 | |
| 34 | static int ecn_parse(int c, char **argv, int invert, unsigned int *flags, |
| 35 | const void *entry, struct xt_entry_match **match) |
| 36 | { |
| 37 | unsigned int result; |
| 38 | struct ipt_ecn_info *einfo |
| 39 | = (struct ipt_ecn_info *)(*match)->data; |
| 40 | |
| 41 | switch (c) { |
| 42 | case 'F': |
| 43 | if (*flags & IPT_ECN_OP_MATCH_CWR) |
| 44 | xtables_error(PARAMETER_PROBLEM, |
| 45 | "ECN match: can only use parameter ONCE!"); |
| 46 | xtables_check_inverse(optarg, &invert, &optind, 0); |
| 47 | einfo->operation |= IPT_ECN_OP_MATCH_CWR; |
| 48 | if (invert) |
| 49 | einfo->invert |= IPT_ECN_OP_MATCH_CWR; |
| 50 | *flags |= IPT_ECN_OP_MATCH_CWR; |
| 51 | break; |
| 52 | |
| 53 | case 'G': |
| 54 | if (*flags & IPT_ECN_OP_MATCH_ECE) |
| 55 | xtables_error(PARAMETER_PROBLEM, |
| 56 | "ECN match: can only use parameter ONCE!"); |
| 57 | xtables_check_inverse(optarg, &invert, &optind, 0); |
| 58 | einfo->operation |= IPT_ECN_OP_MATCH_ECE; |
| 59 | if (invert) |
| 60 | einfo->invert |= IPT_ECN_OP_MATCH_ECE; |
| 61 | *flags |= IPT_ECN_OP_MATCH_ECE; |
| 62 | break; |
| 63 | |
| 64 | case 'H': |
| 65 | if (*flags & IPT_ECN_OP_MATCH_IP) |
| 66 | xtables_error(PARAMETER_PROBLEM, |
| 67 | "ECN match: can only use parameter ONCE!"); |
| 68 | xtables_check_inverse(optarg, &invert, &optind, 0); |
| 69 | if (invert) |
| 70 | einfo->invert |= IPT_ECN_OP_MATCH_IP; |
| 71 | *flags |= IPT_ECN_OP_MATCH_IP; |
| 72 | einfo->operation |= IPT_ECN_OP_MATCH_IP; |
| 73 | if (!xtables_strtoui(optarg, NULL, &result, 0, 3)) |
| 74 | xtables_error(PARAMETER_PROBLEM, |
| 75 | "ECN match: Value out of range"); |
| 76 | einfo->ip_ect = result; |
| 77 | break; |
| 78 | default: |
| 79 | return 0; |
| 80 | } |
| 81 | |
| 82 | return 1; |
| 83 | } |
| 84 | |
| 85 | static void ecn_check(unsigned int flags) |
| 86 | { |
| 87 | if (!flags) |
| 88 | xtables_error(PARAMETER_PROBLEM, |
| 89 | "ECN match: some option required"); |
| 90 | } |
| 91 | |
| 92 | static void ecn_print(const void *ip, const struct xt_entry_match *match, |
| 93 | int numeric) |
| 94 | { |
| 95 | const struct ipt_ecn_info *einfo = |
| 96 | (const struct ipt_ecn_info *)match->data; |
| 97 | |
| 98 | printf("ECN match "); |
| 99 | |
| 100 | if (einfo->operation & IPT_ECN_OP_MATCH_ECE) { |
| 101 | if (einfo->invert & IPT_ECN_OP_MATCH_ECE) |
| 102 | fputc('!', stdout); |
| 103 | printf("ECE "); |
| 104 | } |
| 105 | |
| 106 | if (einfo->operation & IPT_ECN_OP_MATCH_CWR) { |
| 107 | if (einfo->invert & IPT_ECN_OP_MATCH_CWR) |
| 108 | fputc('!', stdout); |
| 109 | printf("CWR "); |
| 110 | } |
| 111 | |
| 112 | if (einfo->operation & IPT_ECN_OP_MATCH_IP) { |
| 113 | if (einfo->invert & IPT_ECN_OP_MATCH_IP) |
| 114 | fputc('!', stdout); |
| 115 | printf("ECT=%d ", einfo->ip_ect); |
| 116 | } |
| 117 | } |
| 118 | |
| 119 | static void ecn_save(const void *ip, const struct xt_entry_match *match) |
| 120 | { |
| 121 | const struct ipt_ecn_info *einfo = |
| 122 | (const struct ipt_ecn_info *)match->data; |
| 123 | |
| 124 | if (einfo->operation & IPT_ECN_OP_MATCH_ECE) { |
| 125 | if (einfo->invert & IPT_ECN_OP_MATCH_ECE) |
| 126 | printf("! "); |
| 127 | printf("--ecn-tcp-ece "); |
| 128 | } |
| 129 | |
| 130 | if (einfo->operation & IPT_ECN_OP_MATCH_CWR) { |
| 131 | if (einfo->invert & IPT_ECN_OP_MATCH_CWR) |
| 132 | printf("! "); |
| 133 | printf("--ecn-tcp-cwr "); |
| 134 | } |
| 135 | |
| 136 | if (einfo->operation & IPT_ECN_OP_MATCH_IP) { |
| 137 | if (einfo->invert & IPT_ECN_OP_MATCH_IP) |
| 138 | printf("! "); |
| 139 | printf("--ecn-ip-ect %d", einfo->ip_ect); |
| 140 | } |
| 141 | } |
| 142 | |
| 143 | static struct xtables_match ecn_mt_reg = { |
| 144 | .name = "ecn", |
| 145 | .version = XTABLES_VERSION, |
| 146 | .family = NFPROTO_IPV4, |
| 147 | .size = XT_ALIGN(sizeof(struct ipt_ecn_info)), |
| 148 | .userspacesize = XT_ALIGN(sizeof(struct ipt_ecn_info)), |
| 149 | .help = ecn_help, |
| 150 | .parse = ecn_parse, |
| 151 | .final_check = ecn_check, |
| 152 | .print = ecn_print, |
| 153 | .save = ecn_save, |
| 154 | .extra_opts = ecn_opts, |
| 155 | }; |
| 156 | |
| 157 | void _init(void) |
| 158 | { |
| 159 | xtables_register_match(&ecn_mt_reg); |
| 160 | } |