xt_dscp.c 2.6 KB

123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106107108109110
  1. // SPDX-License-Identifier: GPL-2.0-only
  2. /* IP tables module for matching the value of the IPv4/IPv6 DSCP field
  3. *
  4. * (C) 2002 by Harald Welte <laforge@netfilter.org>
  5. */
  6. #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  7. #include <linux/module.h>
  8. #include <linux/skbuff.h>
  9. #include <linux/ip.h>
  10. #include <linux/ipv6.h>
  11. #include <net/dsfield.h>
  12. #include <linux/netfilter/x_tables.h>
  13. #include <linux/netfilter/xt_dscp.h>
  14. MODULE_AUTHOR("Harald Welte <laforge@netfilter.org>");
  15. MODULE_DESCRIPTION("Xtables: DSCP/TOS field match");
  16. MODULE_LICENSE("GPL");
  17. MODULE_ALIAS("ipt_dscp");
  18. MODULE_ALIAS("ip6t_dscp");
  19. MODULE_ALIAS("ipt_tos");
  20. MODULE_ALIAS("ip6t_tos");
  21. static bool
  22. dscp_mt(const struct sk_buff *skb, struct xt_action_param *par)
  23. {
  24. const struct xt_dscp_info *info = par->matchinfo;
  25. u_int8_t dscp = ipv4_get_dsfield(ip_hdr(skb)) >> XT_DSCP_SHIFT;
  26. return (dscp == info->dscp) ^ !!info->invert;
  27. }
  28. static bool
  29. dscp_mt6(const struct sk_buff *skb, struct xt_action_param *par)
  30. {
  31. const struct xt_dscp_info *info = par->matchinfo;
  32. u_int8_t dscp = ipv6_get_dsfield(ipv6_hdr(skb)) >> XT_DSCP_SHIFT;
  33. return (dscp == info->dscp) ^ !!info->invert;
  34. }
  35. static int dscp_mt_check(const struct xt_mtchk_param *par)
  36. {
  37. const struct xt_dscp_info *info = par->matchinfo;
  38. if (info->dscp > XT_DSCP_MAX)
  39. return -EDOM;
  40. return 0;
  41. }
  42. static bool tos_mt(const struct sk_buff *skb, struct xt_action_param *par)
  43. {
  44. const struct xt_tos_match_info *info = par->matchinfo;
  45. if (xt_family(par) == NFPROTO_IPV4)
  46. return ((ip_hdr(skb)->tos & info->tos_mask) ==
  47. info->tos_value) ^ !!info->invert;
  48. else
  49. return ((ipv6_get_dsfield(ipv6_hdr(skb)) & info->tos_mask) ==
  50. info->tos_value) ^ !!info->invert;
  51. }
  52. static struct xt_match dscp_mt_reg[] __read_mostly = {
  53. {
  54. .name = "dscp",
  55. .family = NFPROTO_IPV4,
  56. .checkentry = dscp_mt_check,
  57. .match = dscp_mt,
  58. .matchsize = sizeof(struct xt_dscp_info),
  59. .me = THIS_MODULE,
  60. },
  61. {
  62. .name = "dscp",
  63. .family = NFPROTO_IPV6,
  64. .checkentry = dscp_mt_check,
  65. .match = dscp_mt6,
  66. .matchsize = sizeof(struct xt_dscp_info),
  67. .me = THIS_MODULE,
  68. },
  69. {
  70. .name = "tos",
  71. .revision = 1,
  72. .family = NFPROTO_IPV4,
  73. .match = tos_mt,
  74. .matchsize = sizeof(struct xt_tos_match_info),
  75. .me = THIS_MODULE,
  76. },
  77. {
  78. .name = "tos",
  79. .revision = 1,
  80. .family = NFPROTO_IPV6,
  81. .match = tos_mt,
  82. .matchsize = sizeof(struct xt_tos_match_info),
  83. .me = THIS_MODULE,
  84. },
  85. };
  86. static int __init dscp_mt_init(void)
  87. {
  88. return xt_register_matches(dscp_mt_reg, ARRAY_SIZE(dscp_mt_reg));
  89. }
  90. static void __exit dscp_mt_exit(void)
  91. {
  92. xt_unregister_matches(dscp_mt_reg, ARRAY_SIZE(dscp_mt_reg));
  93. }
  94. module_init(dscp_mt_init);
  95. module_exit(dscp_mt_exit);