xt_nat.c 6.5 KB

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  1. // SPDX-License-Identifier: GPL-2.0-only
  2. /*
  3. * (C) 1999-2001 Paul `Rusty' Russell
  4. * (C) 2002-2006 Netfilter Core Team <coreteam@netfilter.org>
  5. * (C) 2011 Patrick McHardy <kaber@trash.net>
  6. */
  7. #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  8. #include <linux/module.h>
  9. #include <linux/skbuff.h>
  10. #include <linux/netfilter.h>
  11. #include <linux/netfilter/x_tables.h>
  12. #include <net/netfilter/nf_nat.h>
  13. static int xt_nat_checkentry_v0(const struct xt_tgchk_param *par)
  14. {
  15. const struct nf_nat_ipv4_multi_range_compat *mr = par->targinfo;
  16. if (mr->rangesize != 1) {
  17. pr_info_ratelimited("multiple ranges no longer supported\n");
  18. return -EINVAL;
  19. }
  20. return nf_ct_netns_get(par->net, par->family);
  21. }
  22. static int xt_nat_checkentry(const struct xt_tgchk_param *par)
  23. {
  24. return nf_ct_netns_get(par->net, par->family);
  25. }
  26. static void xt_nat_destroy(const struct xt_tgdtor_param *par)
  27. {
  28. nf_ct_netns_put(par->net, par->family);
  29. }
  30. static void xt_nat_convert_range(struct nf_nat_range2 *dst,
  31. const struct nf_nat_ipv4_range *src)
  32. {
  33. memset(&dst->min_addr, 0, sizeof(dst->min_addr));
  34. memset(&dst->max_addr, 0, sizeof(dst->max_addr));
  35. memset(&dst->base_proto, 0, sizeof(dst->base_proto));
  36. dst->flags = src->flags;
  37. dst->min_addr.ip = src->min_ip;
  38. dst->max_addr.ip = src->max_ip;
  39. dst->min_proto = src->min;
  40. dst->max_proto = src->max;
  41. }
  42. static unsigned int
  43. xt_snat_target_v0(struct sk_buff *skb, const struct xt_action_param *par)
  44. {
  45. const struct nf_nat_ipv4_multi_range_compat *mr = par->targinfo;
  46. struct nf_nat_range2 range;
  47. enum ip_conntrack_info ctinfo;
  48. struct nf_conn *ct;
  49. ct = nf_ct_get(skb, &ctinfo);
  50. WARN_ON(!(ct != NULL &&
  51. (ctinfo == IP_CT_NEW || ctinfo == IP_CT_RELATED ||
  52. ctinfo == IP_CT_RELATED_REPLY)));
  53. xt_nat_convert_range(&range, &mr->range[0]);
  54. return nf_nat_setup_info(ct, &range, NF_NAT_MANIP_SRC);
  55. }
  56. static unsigned int
  57. xt_dnat_target_v0(struct sk_buff *skb, const struct xt_action_param *par)
  58. {
  59. const struct nf_nat_ipv4_multi_range_compat *mr = par->targinfo;
  60. struct nf_nat_range2 range;
  61. enum ip_conntrack_info ctinfo;
  62. struct nf_conn *ct;
  63. ct = nf_ct_get(skb, &ctinfo);
  64. WARN_ON(!(ct != NULL &&
  65. (ctinfo == IP_CT_NEW || ctinfo == IP_CT_RELATED)));
  66. xt_nat_convert_range(&range, &mr->range[0]);
  67. return nf_nat_setup_info(ct, &range, NF_NAT_MANIP_DST);
  68. }
  69. static unsigned int
  70. xt_snat_target_v1(struct sk_buff *skb, const struct xt_action_param *par)
  71. {
  72. const struct nf_nat_range *range_v1 = par->targinfo;
  73. struct nf_nat_range2 range;
  74. enum ip_conntrack_info ctinfo;
  75. struct nf_conn *ct;
  76. ct = nf_ct_get(skb, &ctinfo);
  77. WARN_ON(!(ct != NULL &&
  78. (ctinfo == IP_CT_NEW || ctinfo == IP_CT_RELATED ||
  79. ctinfo == IP_CT_RELATED_REPLY)));
  80. memcpy(&range, range_v1, sizeof(*range_v1));
  81. memset(&range.base_proto, 0, sizeof(range.base_proto));
  82. return nf_nat_setup_info(ct, &range, NF_NAT_MANIP_SRC);
  83. }
  84. static unsigned int
  85. xt_dnat_target_v1(struct sk_buff *skb, const struct xt_action_param *par)
  86. {
  87. const struct nf_nat_range *range_v1 = par->targinfo;
  88. struct nf_nat_range2 range;
  89. enum ip_conntrack_info ctinfo;
  90. struct nf_conn *ct;
  91. ct = nf_ct_get(skb, &ctinfo);
  92. WARN_ON(!(ct != NULL &&
  93. (ctinfo == IP_CT_NEW || ctinfo == IP_CT_RELATED)));
  94. memcpy(&range, range_v1, sizeof(*range_v1));
  95. memset(&range.base_proto, 0, sizeof(range.base_proto));
  96. return nf_nat_setup_info(ct, &range, NF_NAT_MANIP_DST);
  97. }
  98. static unsigned int
  99. xt_snat_target_v2(struct sk_buff *skb, const struct xt_action_param *par)
  100. {
  101. const struct nf_nat_range2 *range = par->targinfo;
  102. enum ip_conntrack_info ctinfo;
  103. struct nf_conn *ct;
  104. ct = nf_ct_get(skb, &ctinfo);
  105. WARN_ON(!(ct != NULL &&
  106. (ctinfo == IP_CT_NEW || ctinfo == IP_CT_RELATED ||
  107. ctinfo == IP_CT_RELATED_REPLY)));
  108. return nf_nat_setup_info(ct, range, NF_NAT_MANIP_SRC);
  109. }
  110. static unsigned int
  111. xt_dnat_target_v2(struct sk_buff *skb, const struct xt_action_param *par)
  112. {
  113. const struct nf_nat_range2 *range = par->targinfo;
  114. enum ip_conntrack_info ctinfo;
  115. struct nf_conn *ct;
  116. ct = nf_ct_get(skb, &ctinfo);
  117. WARN_ON(!(ct != NULL &&
  118. (ctinfo == IP_CT_NEW || ctinfo == IP_CT_RELATED)));
  119. return nf_nat_setup_info(ct, range, NF_NAT_MANIP_DST);
  120. }
  121. static struct xt_target xt_nat_target_reg[] __read_mostly = {
  122. {
  123. .name = "SNAT",
  124. .revision = 0,
  125. .checkentry = xt_nat_checkentry_v0,
  126. .destroy = xt_nat_destroy,
  127. .target = xt_snat_target_v0,
  128. .targetsize = sizeof(struct nf_nat_ipv4_multi_range_compat),
  129. .family = NFPROTO_IPV4,
  130. .table = "nat",
  131. .hooks = (1 << NF_INET_POST_ROUTING) |
  132. (1 << NF_INET_LOCAL_IN),
  133. .me = THIS_MODULE,
  134. },
  135. {
  136. .name = "DNAT",
  137. .revision = 0,
  138. .checkentry = xt_nat_checkentry_v0,
  139. .destroy = xt_nat_destroy,
  140. .target = xt_dnat_target_v0,
  141. .targetsize = sizeof(struct nf_nat_ipv4_multi_range_compat),
  142. .family = NFPROTO_IPV4,
  143. .table = "nat",
  144. .hooks = (1 << NF_INET_PRE_ROUTING) |
  145. (1 << NF_INET_LOCAL_OUT),
  146. .me = THIS_MODULE,
  147. },
  148. {
  149. .name = "SNAT",
  150. .revision = 1,
  151. .checkentry = xt_nat_checkentry,
  152. .destroy = xt_nat_destroy,
  153. .target = xt_snat_target_v1,
  154. .targetsize = sizeof(struct nf_nat_range),
  155. .table = "nat",
  156. .hooks = (1 << NF_INET_POST_ROUTING) |
  157. (1 << NF_INET_LOCAL_IN),
  158. .me = THIS_MODULE,
  159. },
  160. {
  161. .name = "DNAT",
  162. .revision = 1,
  163. .checkentry = xt_nat_checkentry,
  164. .destroy = xt_nat_destroy,
  165. .target = xt_dnat_target_v1,
  166. .targetsize = sizeof(struct nf_nat_range),
  167. .table = "nat",
  168. .hooks = (1 << NF_INET_PRE_ROUTING) |
  169. (1 << NF_INET_LOCAL_OUT),
  170. .me = THIS_MODULE,
  171. },
  172. {
  173. .name = "SNAT",
  174. .revision = 2,
  175. .checkentry = xt_nat_checkentry,
  176. .destroy = xt_nat_destroy,
  177. .target = xt_snat_target_v2,
  178. .targetsize = sizeof(struct nf_nat_range2),
  179. .table = "nat",
  180. .hooks = (1 << NF_INET_POST_ROUTING) |
  181. (1 << NF_INET_LOCAL_IN),
  182. .me = THIS_MODULE,
  183. },
  184. {
  185. .name = "DNAT",
  186. .revision = 2,
  187. .checkentry = xt_nat_checkentry,
  188. .destroy = xt_nat_destroy,
  189. .target = xt_dnat_target_v2,
  190. .targetsize = sizeof(struct nf_nat_range2),
  191. .table = "nat",
  192. .hooks = (1 << NF_INET_PRE_ROUTING) |
  193. (1 << NF_INET_LOCAL_OUT),
  194. .me = THIS_MODULE,
  195. },
  196. };
  197. static int __init xt_nat_init(void)
  198. {
  199. return xt_register_targets(xt_nat_target_reg,
  200. ARRAY_SIZE(xt_nat_target_reg));
  201. }
  202. static void __exit xt_nat_exit(void)
  203. {
  204. xt_unregister_targets(xt_nat_target_reg, ARRAY_SIZE(xt_nat_target_reg));
  205. }
  206. module_init(xt_nat_init);
  207. module_exit(xt_nat_exit);
  208. MODULE_LICENSE("GPL");
  209. MODULE_AUTHOR("Patrick McHardy <kaber@trash.net>");
  210. MODULE_ALIAS("ipt_SNAT");
  211. MODULE_ALIAS("ipt_DNAT");
  212. MODULE_ALIAS("ip6t_SNAT");
  213. MODULE_ALIAS("ip6t_DNAT");
  214. MODULE_DESCRIPTION("SNAT and DNAT targets support");