Rusty Russell | 2ce6ec6 | 2000-08-30 05:49:06 +0000 | [diff] [blame] | 1 | /* Shared library add-on to iptables to add tcp MSS matching support. */ |
| 2 | #include <stdio.h> |
| 3 | #include <netdb.h> |
| 4 | #include <string.h> |
| 5 | #include <stdlib.h> |
| 6 | #include <getopt.h> |
| 7 | |
Yasuyuki KOZAKAI | 7999bd3 | 2007-07-24 06:57:56 +0000 | [diff] [blame] | 8 | #include <xtables.h> |
| 9 | #include <linux/netfilter/xt_tcpmss.h> |
Rusty Russell | 2ce6ec6 | 2000-08-30 05:49:06 +0000 | [diff] [blame] | 10 | |
Jan Engelhardt | 181dead | 2007-10-04 16:27:07 +0000 | [diff] [blame] | 11 | static void tcpmss_help(void) |
Rusty Russell | 2ce6ec6 | 2000-08-30 05:49:06 +0000 | [diff] [blame] | 12 | { |
| 13 | printf( |
Jan Engelhardt | 8b7c64d | 2008-04-15 11:48:25 +0200 | [diff] [blame] | 14 | "tcpmss match options:\n" |
Rusty Russell | 2ce6ec6 | 2000-08-30 05:49:06 +0000 | [diff] [blame] | 15 | "[!] --mss value[:value] Match TCP MSS range.\n" |
Jan Engelhardt | 8b7c64d | 2008-04-15 11:48:25 +0200 | [diff] [blame] | 16 | " (only valid for TCP SYN or SYN/ACK packets)\n"); |
Rusty Russell | 2ce6ec6 | 2000-08-30 05:49:06 +0000 | [diff] [blame] | 17 | } |
| 18 | |
Jan Engelhardt | 181dead | 2007-10-04 16:27:07 +0000 | [diff] [blame] | 19 | static const struct option tcpmss_opts[] = { |
Patrick McHardy | 500f483 | 2007-09-08 15:59:04 +0000 | [diff] [blame] | 20 | { "mss", 1, NULL, '1' }, |
Max Kellermann | 9ee386a | 2008-01-29 13:48:05 +0000 | [diff] [blame] | 21 | { .name = NULL } |
Rusty Russell | 2ce6ec6 | 2000-08-30 05:49:06 +0000 | [diff] [blame] | 22 | }; |
| 23 | |
Rusty Russell | 2ce6ec6 | 2000-08-30 05:49:06 +0000 | [diff] [blame] | 24 | static u_int16_t |
| 25 | parse_tcp_mssvalue(const char *mssvalue) |
| 26 | { |
Harald Welte | b471976 | 2001-07-23 02:14:22 +0000 | [diff] [blame] | 27 | unsigned int mssvaluenum; |
Rusty Russell | 2ce6ec6 | 2000-08-30 05:49:06 +0000 | [diff] [blame] | 28 | |
Jan Engelhardt | 5f2922c | 2009-01-27 18:43:01 +0100 | [diff] [blame] | 29 | if (!xtables_strtoui(mssvalue, NULL, &mssvaluenum, 0, UINT16_MAX)) |
Jan Engelhardt | 213e185 | 2009-01-27 17:24:34 +0100 | [diff] [blame] | 30 | return mssvaluenum; |
Rusty Russell | 2ce6ec6 | 2000-08-30 05:49:06 +0000 | [diff] [blame] | 31 | |
| 32 | exit_error(PARAMETER_PROBLEM, |
| 33 | "Invalid mss `%s' specified", mssvalue); |
| 34 | } |
| 35 | |
| 36 | static void |
| 37 | parse_tcp_mssvalues(const char *mssvaluestring, |
| 38 | u_int16_t *mss_min, u_int16_t *mss_max) |
| 39 | { |
| 40 | char *buffer; |
| 41 | char *cp; |
| 42 | |
| 43 | buffer = strdup(mssvaluestring); |
| 44 | if ((cp = strchr(buffer, ':')) == NULL) |
Rusty Russell | d4a8b28 | 2000-08-31 11:22:14 +0000 | [diff] [blame] | 45 | *mss_min = *mss_max = parse_tcp_mssvalue(buffer); |
Rusty Russell | 2ce6ec6 | 2000-08-30 05:49:06 +0000 | [diff] [blame] | 46 | else { |
| 47 | *cp = '\0'; |
| 48 | cp++; |
| 49 | |
Rusty Russell | d4a8b28 | 2000-08-31 11:22:14 +0000 | [diff] [blame] | 50 | *mss_min = buffer[0] ? parse_tcp_mssvalue(buffer) : 0; |
| 51 | *mss_max = cp[0] ? parse_tcp_mssvalue(cp) : 0xFFFF; |
Rusty Russell | 2ce6ec6 | 2000-08-30 05:49:06 +0000 | [diff] [blame] | 52 | } |
| 53 | free(buffer); |
| 54 | } |
| 55 | |
Rusty Russell | 2ce6ec6 | 2000-08-30 05:49:06 +0000 | [diff] [blame] | 56 | static int |
Jan Engelhardt | 181dead | 2007-10-04 16:27:07 +0000 | [diff] [blame] | 57 | tcpmss_parse(int c, char **argv, int invert, unsigned int *flags, |
| 58 | const void *entry, struct xt_entry_match **match) |
Rusty Russell | 2ce6ec6 | 2000-08-30 05:49:06 +0000 | [diff] [blame] | 59 | { |
Yasuyuki KOZAKAI | 7999bd3 | 2007-07-24 06:57:56 +0000 | [diff] [blame] | 60 | struct xt_tcpmss_match_info *mssinfo = |
| 61 | (struct xt_tcpmss_match_info *)(*match)->data; |
Rusty Russell | 2ce6ec6 | 2000-08-30 05:49:06 +0000 | [diff] [blame] | 62 | |
| 63 | switch (c) { |
| 64 | case '1': |
| 65 | if (*flags) |
| 66 | exit_error(PARAMETER_PROBLEM, |
| 67 | "Only one `--mss' allowed"); |
Harald Welte | b77f1da | 2002-03-14 11:35:58 +0000 | [diff] [blame] | 68 | check_inverse(optarg, &invert, &optind, 0); |
Rusty Russell | 2ce6ec6 | 2000-08-30 05:49:06 +0000 | [diff] [blame] | 69 | parse_tcp_mssvalues(argv[optind-1], |
| 70 | &mssinfo->mss_min, &mssinfo->mss_max); |
| 71 | if (invert) |
| 72 | mssinfo->invert = 1; |
| 73 | *flags = 1; |
| 74 | break; |
| 75 | default: |
| 76 | return 0; |
| 77 | } |
| 78 | return 1; |
| 79 | } |
| 80 | |
Jan Engelhardt | 181dead | 2007-10-04 16:27:07 +0000 | [diff] [blame] | 81 | static void tcpmss_check(unsigned int flags) |
Rusty Russell | 2ce6ec6 | 2000-08-30 05:49:06 +0000 | [diff] [blame] | 82 | { |
| 83 | if (!flags) |
| 84 | exit_error(PARAMETER_PROBLEM, |
| 85 | "tcpmss match: You must specify `--mss'"); |
| 86 | } |
| 87 | |
Rusty Russell | 2ce6ec6 | 2000-08-30 05:49:06 +0000 | [diff] [blame] | 88 | static void |
Jan Engelhardt | 181dead | 2007-10-04 16:27:07 +0000 | [diff] [blame] | 89 | tcpmss_print(const void *ip, const struct xt_entry_match *match, int numeric) |
Rusty Russell | 2ce6ec6 | 2000-08-30 05:49:06 +0000 | [diff] [blame] | 90 | { |
Jan Engelhardt | cea9f71 | 2008-12-09 15:06:20 +0100 | [diff] [blame] | 91 | const struct xt_tcpmss_match_info *info = (void *)match->data; |
Rusty Russell | 2ce6ec6 | 2000-08-30 05:49:06 +0000 | [diff] [blame] | 92 | |
Jan Engelhardt | cea9f71 | 2008-12-09 15:06:20 +0100 | [diff] [blame] | 93 | printf("tcpmss match %s", info->invert ? "!" : ""); |
| 94 | if (info->mss_min == info->mss_max) |
| 95 | printf("%u ", info->mss_min); |
| 96 | else |
| 97 | printf("%u:%u ", info->mss_min, info->mss_max); |
Rusty Russell | 2ce6ec6 | 2000-08-30 05:49:06 +0000 | [diff] [blame] | 98 | } |
| 99 | |
Jan Engelhardt | 181dead | 2007-10-04 16:27:07 +0000 | [diff] [blame] | 100 | static void tcpmss_save(const void *ip, const struct xt_entry_match *match) |
Rusty Russell | 2ce6ec6 | 2000-08-30 05:49:06 +0000 | [diff] [blame] | 101 | { |
Jan Engelhardt | cea9f71 | 2008-12-09 15:06:20 +0100 | [diff] [blame] | 102 | const struct xt_tcpmss_match_info *info = (void *)match->data; |
Rusty Russell | 2ce6ec6 | 2000-08-30 05:49:06 +0000 | [diff] [blame] | 103 | |
Jan Engelhardt | cea9f71 | 2008-12-09 15:06:20 +0100 | [diff] [blame] | 104 | printf("%s--mss ", info->invert ? "! " : ""); |
| 105 | if (info->mss_min == info->mss_max) |
| 106 | printf("%u ", info->mss_min); |
| 107 | else |
| 108 | printf("%u:%u ", info->mss_min, info->mss_max); |
Rusty Russell | 2ce6ec6 | 2000-08-30 05:49:06 +0000 | [diff] [blame] | 109 | } |
| 110 | |
Jan Engelhardt | 181dead | 2007-10-04 16:27:07 +0000 | [diff] [blame] | 111 | static struct xtables_match tcpmss_match = { |
Jan Engelhardt | 03d9948 | 2008-11-18 12:27:54 +0100 | [diff] [blame] | 112 | .family = NFPROTO_IPV4, |
Pablo Neira | 8caee8b | 2004-12-28 13:11:59 +0000 | [diff] [blame] | 113 | .name = "tcpmss", |
Jan Engelhardt | 8b7c64d | 2008-04-15 11:48:25 +0200 | [diff] [blame] | 114 | .version = XTABLES_VERSION, |
Yasuyuki KOZAKAI | 7999bd3 | 2007-07-24 06:57:56 +0000 | [diff] [blame] | 115 | .size = XT_ALIGN(sizeof(struct xt_tcpmss_match_info)), |
| 116 | .userspacesize = XT_ALIGN(sizeof(struct xt_tcpmss_match_info)), |
Jan Engelhardt | 181dead | 2007-10-04 16:27:07 +0000 | [diff] [blame] | 117 | .help = tcpmss_help, |
| 118 | .parse = tcpmss_parse, |
| 119 | .final_check = tcpmss_check, |
| 120 | .print = tcpmss_print, |
| 121 | .save = tcpmss_save, |
| 122 | .extra_opts = tcpmss_opts, |
Yasuyuki KOZAKAI | 7999bd3 | 2007-07-24 06:57:56 +0000 | [diff] [blame] | 123 | }; |
| 124 | |
Jan Engelhardt | 181dead | 2007-10-04 16:27:07 +0000 | [diff] [blame] | 125 | static struct xtables_match tcpmss_match6 = { |
Jan Engelhardt | 03d9948 | 2008-11-18 12:27:54 +0100 | [diff] [blame] | 126 | .family = NFPROTO_IPV6, |
Yasuyuki KOZAKAI | 7999bd3 | 2007-07-24 06:57:56 +0000 | [diff] [blame] | 127 | .name = "tcpmss", |
Jan Engelhardt | 8b7c64d | 2008-04-15 11:48:25 +0200 | [diff] [blame] | 128 | .version = XTABLES_VERSION, |
Yasuyuki KOZAKAI | 7999bd3 | 2007-07-24 06:57:56 +0000 | [diff] [blame] | 129 | .size = XT_ALIGN(sizeof(struct xt_tcpmss_match_info)), |
| 130 | .userspacesize = XT_ALIGN(sizeof(struct xt_tcpmss_match_info)), |
Jan Engelhardt | 181dead | 2007-10-04 16:27:07 +0000 | [diff] [blame] | 131 | .help = tcpmss_help, |
| 132 | .parse = tcpmss_parse, |
| 133 | .final_check = tcpmss_check, |
| 134 | .print = tcpmss_print, |
| 135 | .save = tcpmss_save, |
| 136 | .extra_opts = tcpmss_opts, |
Rusty Russell | 2ce6ec6 | 2000-08-30 05:49:06 +0000 | [diff] [blame] | 137 | }; |
| 138 | |
| 139 | void _init(void) |
| 140 | { |
Jan Engelhardt | 181dead | 2007-10-04 16:27:07 +0000 | [diff] [blame] | 141 | xtables_register_match(&tcpmss_match); |
| 142 | xtables_register_match(&tcpmss_match6); |
Rusty Russell | 2ce6ec6 | 2000-08-30 05:49:06 +0000 | [diff] [blame] | 143 | } |