Yasuyuki KOZAKAI | 45e4c69 | 2007-07-24 07:22:24 +0000 | [diff] [blame] | 1 | /* Shared library add-on to iptables to add TCPMSS target support. |
| 2 | * |
| 3 | * Copyright (c) 2000 Marc Boucher |
| 4 | */ |
Jan Engelhardt | 4d8656a | 2011-07-22 12:25:43 +0200 | [diff] [blame] | 5 | #include "config.h" |
Yasuyuki KOZAKAI | 45e4c69 | 2007-07-24 07:22:24 +0000 | [diff] [blame] | 6 | #include <stdio.h> |
Yasuyuki KOZAKAI | 45e4c69 | 2007-07-24 07:22:24 +0000 | [diff] [blame] | 7 | #include <xtables.h> |
Jan Engelhardt | ea2a02f | 2011-03-06 18:00:05 +0100 | [diff] [blame] | 8 | #include <netinet/ip.h> |
Yasuyuki KOZAKAI | 45e4c69 | 2007-07-24 07:22:24 +0000 | [diff] [blame] | 9 | #include <linux/netfilter/xt_TCPMSS.h> |
| 10 | |
Jan Engelhardt | ea2a02f | 2011-03-06 18:00:05 +0100 | [diff] [blame] | 11 | enum { |
| 12 | O_SET_MSS = 0, |
| 13 | O_CLAMP_MSS, |
| 14 | }; |
| 15 | |
Yasuyuki KOZAKAI | 45e4c69 | 2007-07-24 07:22:24 +0000 | [diff] [blame] | 16 | struct mssinfo { |
| 17 | struct xt_entry_target t; |
| 18 | struct xt_tcpmss_info mss; |
| 19 | }; |
| 20 | |
Jan Engelhardt | 932e648 | 2007-10-04 16:27:30 +0000 | [diff] [blame] | 21 | static void __TCPMSS_help(int hdrsize) |
Yasuyuki KOZAKAI | 45e4c69 | 2007-07-24 07:22:24 +0000 | [diff] [blame] | 22 | { |
| 23 | printf( |
Jan Engelhardt | 8b7c64d | 2008-04-15 11:48:25 +0200 | [diff] [blame] | 24 | "TCPMSS target mutually-exclusive options:\n" |
Yasuyuki KOZAKAI | 45e4c69 | 2007-07-24 07:22:24 +0000 | [diff] [blame] | 25 | " --set-mss value explicitly set MSS option to specified value\n" |
| 26 | " --clamp-mss-to-pmtu automatically clamp MSS value to (path_MTU - %d)\n", |
Jan Engelhardt | 8b7c64d | 2008-04-15 11:48:25 +0200 | [diff] [blame] | 27 | hdrsize); |
Yasuyuki KOZAKAI | 45e4c69 | 2007-07-24 07:22:24 +0000 | [diff] [blame] | 28 | } |
| 29 | |
Jan Engelhardt | 932e648 | 2007-10-04 16:27:30 +0000 | [diff] [blame] | 30 | static void TCPMSS_help(void) |
Yasuyuki KOZAKAI | 45e4c69 | 2007-07-24 07:22:24 +0000 | [diff] [blame] | 31 | { |
Jan Engelhardt | ea2a02f | 2011-03-06 18:00:05 +0100 | [diff] [blame] | 32 | __TCPMSS_help(sizeof(struct iphdr)); |
Yasuyuki KOZAKAI | 45e4c69 | 2007-07-24 07:22:24 +0000 | [diff] [blame] | 33 | } |
| 34 | |
Jan Engelhardt | 932e648 | 2007-10-04 16:27:30 +0000 | [diff] [blame] | 35 | static void TCPMSS_help6(void) |
Yasuyuki KOZAKAI | 45e4c69 | 2007-07-24 07:22:24 +0000 | [diff] [blame] | 36 | { |
Jan Engelhardt | 4d8656a | 2011-07-22 12:25:43 +0200 | [diff] [blame] | 37 | __TCPMSS_help(SIZEOF_STRUCT_IP6_HDR); |
Yasuyuki KOZAKAI | 45e4c69 | 2007-07-24 07:22:24 +0000 | [diff] [blame] | 38 | } |
| 39 | |
Jan Engelhardt | ea2a02f | 2011-03-06 18:00:05 +0100 | [diff] [blame] | 40 | static const struct xt_option_entry TCPMSS4_opts[] = { |
| 41 | {.name = "set-mss", .id = O_SET_MSS, .type = XTTYPE_UINT16, |
| 42 | .min = 0, .max = UINT16_MAX - sizeof(struct iphdr), |
| 43 | .flags = XTOPT_PUT, XTOPT_POINTER(struct xt_tcpmss_info, mss)}, |
| 44 | {.name = "clamp-mss-to-pmtu", .id = O_CLAMP_MSS, .type = XTTYPE_NONE}, |
| 45 | XTOPT_TABLEEND, |
Yasuyuki KOZAKAI | 45e4c69 | 2007-07-24 07:22:24 +0000 | [diff] [blame] | 46 | }; |
| 47 | |
Jan Engelhardt | ea2a02f | 2011-03-06 18:00:05 +0100 | [diff] [blame] | 48 | static const struct xt_option_entry TCPMSS6_opts[] = { |
| 49 | {.name = "set-mss", .id = O_SET_MSS, .type = XTTYPE_UINT16, |
Jan Engelhardt | 4d8656a | 2011-07-22 12:25:43 +0200 | [diff] [blame] | 50 | .min = 0, .max = UINT16_MAX - SIZEOF_STRUCT_IP6_HDR, |
Jan Engelhardt | ea2a02f | 2011-03-06 18:00:05 +0100 | [diff] [blame] | 51 | .flags = XTOPT_PUT, XTOPT_POINTER(struct xt_tcpmss_info, mss)}, |
| 52 | {.name = "clamp-mss-to-pmtu", .id = O_CLAMP_MSS, .type = XTTYPE_NONE}, |
| 53 | XTOPT_TABLEEND, |
| 54 | }; |
| 55 | |
| 56 | static void TCPMSS_parse(struct xt_option_call *cb) |
Yasuyuki KOZAKAI | 45e4c69 | 2007-07-24 07:22:24 +0000 | [diff] [blame] | 57 | { |
Jan Engelhardt | ea2a02f | 2011-03-06 18:00:05 +0100 | [diff] [blame] | 58 | struct xt_tcpmss_info *mssinfo = cb->data; |
Yasuyuki KOZAKAI | 45e4c69 | 2007-07-24 07:22:24 +0000 | [diff] [blame] | 59 | |
Jan Engelhardt | ea2a02f | 2011-03-06 18:00:05 +0100 | [diff] [blame] | 60 | xtables_option_parse(cb); |
| 61 | if (cb->entry->id == O_CLAMP_MSS) |
Yasuyuki KOZAKAI | 45e4c69 | 2007-07-24 07:22:24 +0000 | [diff] [blame] | 62 | mssinfo->mss = XT_TCPMSS_CLAMP_PMTU; |
Yasuyuki KOZAKAI | 45e4c69 | 2007-07-24 07:22:24 +0000 | [diff] [blame] | 63 | } |
| 64 | |
Jan Engelhardt | ea2a02f | 2011-03-06 18:00:05 +0100 | [diff] [blame] | 65 | static void TCPMSS_check(struct xt_fcheck_call *cb) |
Yasuyuki KOZAKAI | 45e4c69 | 2007-07-24 07:22:24 +0000 | [diff] [blame] | 66 | { |
Jan Engelhardt | ea2a02f | 2011-03-06 18:00:05 +0100 | [diff] [blame] | 67 | if (cb->xflags == 0) |
Jan Engelhardt | 1829ed4 | 2009-02-21 03:29:44 +0100 | [diff] [blame] | 68 | xtables_error(PARAMETER_PROBLEM, |
Yasuyuki KOZAKAI | 45e4c69 | 2007-07-24 07:22:24 +0000 | [diff] [blame] | 69 | "TCPMSS target: At least one parameter is required"); |
| 70 | } |
| 71 | |
Jan Engelhardt | 932e648 | 2007-10-04 16:27:30 +0000 | [diff] [blame] | 72 | static void TCPMSS_print(const void *ip, const struct xt_entry_target *target, |
| 73 | int numeric) |
Yasuyuki KOZAKAI | 45e4c69 | 2007-07-24 07:22:24 +0000 | [diff] [blame] | 74 | { |
| 75 | const struct xt_tcpmss_info *mssinfo = |
| 76 | (const struct xt_tcpmss_info *)target->data; |
| 77 | if(mssinfo->mss == XT_TCPMSS_CLAMP_PMTU) |
Jan Engelhardt | 7386635 | 2010-12-18 02:04:59 +0100 | [diff] [blame] | 78 | printf(" TCPMSS clamp to PMTU"); |
Yasuyuki KOZAKAI | 45e4c69 | 2007-07-24 07:22:24 +0000 | [diff] [blame] | 79 | else |
Jan Engelhardt | 7386635 | 2010-12-18 02:04:59 +0100 | [diff] [blame] | 80 | printf(" TCPMSS set %u", mssinfo->mss); |
Yasuyuki KOZAKAI | 45e4c69 | 2007-07-24 07:22:24 +0000 | [diff] [blame] | 81 | } |
| 82 | |
Jan Engelhardt | 932e648 | 2007-10-04 16:27:30 +0000 | [diff] [blame] | 83 | static void TCPMSS_save(const void *ip, const struct xt_entry_target *target) |
Yasuyuki KOZAKAI | 45e4c69 | 2007-07-24 07:22:24 +0000 | [diff] [blame] | 84 | { |
| 85 | const struct xt_tcpmss_info *mssinfo = |
| 86 | (const struct xt_tcpmss_info *)target->data; |
| 87 | |
| 88 | if(mssinfo->mss == XT_TCPMSS_CLAMP_PMTU) |
Jan Engelhardt | 7386635 | 2010-12-18 02:04:59 +0100 | [diff] [blame] | 89 | printf(" --clamp-mss-to-pmtu"); |
Yasuyuki KOZAKAI | 45e4c69 | 2007-07-24 07:22:24 +0000 | [diff] [blame] | 90 | else |
Jan Engelhardt | 7386635 | 2010-12-18 02:04:59 +0100 | [diff] [blame] | 91 | printf(" --set-mss %u", mssinfo->mss); |
Yasuyuki KOZAKAI | 45e4c69 | 2007-07-24 07:22:24 +0000 | [diff] [blame] | 92 | } |
| 93 | |
Jan Engelhardt | 1757ec8 | 2011-07-22 12:11:03 +0200 | [diff] [blame] | 94 | static struct xtables_target tcpmss_tg_reg[] = { |
| 95 | { |
| 96 | .family = NFPROTO_IPV4, |
| 97 | .name = "TCPMSS", |
| 98 | .version = XTABLES_VERSION, |
| 99 | .size = XT_ALIGN(sizeof(struct xt_tcpmss_info)), |
| 100 | .userspacesize = XT_ALIGN(sizeof(struct xt_tcpmss_info)), |
| 101 | .help = TCPMSS_help, |
| 102 | .print = TCPMSS_print, |
| 103 | .save = TCPMSS_save, |
| 104 | .x6_parse = TCPMSS_parse, |
| 105 | .x6_fcheck = TCPMSS_check, |
| 106 | .x6_options = TCPMSS4_opts, |
| 107 | }, |
| 108 | { |
| 109 | .family = NFPROTO_IPV6, |
| 110 | .name = "TCPMSS", |
| 111 | .version = XTABLES_VERSION, |
| 112 | .size = XT_ALIGN(sizeof(struct xt_tcpmss_info)), |
| 113 | .userspacesize = XT_ALIGN(sizeof(struct xt_tcpmss_info)), |
| 114 | .help = TCPMSS_help6, |
| 115 | .print = TCPMSS_print, |
| 116 | .save = TCPMSS_save, |
| 117 | .x6_parse = TCPMSS_parse, |
| 118 | .x6_fcheck = TCPMSS_check, |
| 119 | .x6_options = TCPMSS6_opts, |
| 120 | }, |
Yasuyuki KOZAKAI | 45e4c69 | 2007-07-24 07:22:24 +0000 | [diff] [blame] | 121 | }; |
| 122 | |
| 123 | void _init(void) |
| 124 | { |
Jan Engelhardt | 1757ec8 | 2011-07-22 12:11:03 +0200 | [diff] [blame] | 125 | xtables_register_targets(tcpmss_tg_reg, ARRAY_SIZE(tcpmss_tg_reg)); |
Yasuyuki KOZAKAI | 45e4c69 | 2007-07-24 07:22:24 +0000 | [diff] [blame] | 126 | } |