nft_dup_ipv4.c 2.9 KB

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  1. // SPDX-License-Identifier: GPL-2.0-only
  2. /*
  3. * Copyright (c) 2015 Pablo Neira Ayuso <pablo@netfilter.org>
  4. */
  5. #include <linux/kernel.h>
  6. #include <linux/init.h>
  7. #include <linux/module.h>
  8. #include <linux/netlink.h>
  9. #include <linux/netfilter.h>
  10. #include <linux/netfilter/nf_tables.h>
  11. #include <net/netfilter/nf_tables.h>
  12. #include <net/netfilter/ipv4/nf_dup_ipv4.h>
  13. struct nft_dup_ipv4 {
  14. enum nft_registers sreg_addr:8;
  15. enum nft_registers sreg_dev:8;
  16. };
  17. static void nft_dup_ipv4_eval(const struct nft_expr *expr,
  18. struct nft_regs *regs,
  19. const struct nft_pktinfo *pkt)
  20. {
  21. struct nft_dup_ipv4 *priv = nft_expr_priv(expr);
  22. struct in_addr gw = {
  23. .s_addr = (__force __be32)regs->data[priv->sreg_addr],
  24. };
  25. int oif = priv->sreg_dev ? regs->data[priv->sreg_dev] : -1;
  26. nf_dup_ipv4(nft_net(pkt), pkt->skb, nft_hook(pkt), &gw, oif);
  27. }
  28. static int nft_dup_ipv4_init(const struct nft_ctx *ctx,
  29. const struct nft_expr *expr,
  30. const struct nlattr * const tb[])
  31. {
  32. struct nft_dup_ipv4 *priv = nft_expr_priv(expr);
  33. int err;
  34. if (tb[NFTA_DUP_SREG_ADDR] == NULL)
  35. return -EINVAL;
  36. priv->sreg_addr = nft_parse_register(tb[NFTA_DUP_SREG_ADDR]);
  37. err = nft_validate_register_load(priv->sreg_addr, sizeof(struct in_addr));
  38. if (err < 0)
  39. return err;
  40. if (tb[NFTA_DUP_SREG_DEV] != NULL) {
  41. priv->sreg_dev = nft_parse_register(tb[NFTA_DUP_SREG_DEV]);
  42. return nft_validate_register_load(priv->sreg_dev, sizeof(int));
  43. }
  44. return 0;
  45. }
  46. static int nft_dup_ipv4_dump(struct sk_buff *skb, const struct nft_expr *expr)
  47. {
  48. struct nft_dup_ipv4 *priv = nft_expr_priv(expr);
  49. if (nft_dump_register(skb, NFTA_DUP_SREG_ADDR, priv->sreg_addr))
  50. goto nla_put_failure;
  51. if (priv->sreg_dev &&
  52. nft_dump_register(skb, NFTA_DUP_SREG_DEV, priv->sreg_dev))
  53. goto nla_put_failure;
  54. return 0;
  55. nla_put_failure:
  56. return -1;
  57. }
  58. static struct nft_expr_type nft_dup_ipv4_type;
  59. static const struct nft_expr_ops nft_dup_ipv4_ops = {
  60. .type = &nft_dup_ipv4_type,
  61. .size = NFT_EXPR_SIZE(sizeof(struct nft_dup_ipv4)),
  62. .eval = nft_dup_ipv4_eval,
  63. .init = nft_dup_ipv4_init,
  64. .dump = nft_dup_ipv4_dump,
  65. };
  66. static const struct nla_policy nft_dup_ipv4_policy[NFTA_DUP_MAX + 1] = {
  67. [NFTA_DUP_SREG_ADDR] = { .type = NLA_U32 },
  68. [NFTA_DUP_SREG_DEV] = { .type = NLA_U32 },
  69. };
  70. static struct nft_expr_type nft_dup_ipv4_type __read_mostly = {
  71. .family = NFPROTO_IPV4,
  72. .name = "dup",
  73. .ops = &nft_dup_ipv4_ops,
  74. .policy = nft_dup_ipv4_policy,
  75. .maxattr = NFTA_DUP_MAX,
  76. .owner = THIS_MODULE,
  77. };
  78. static int __init nft_dup_ipv4_module_init(void)
  79. {
  80. return nft_register_expr(&nft_dup_ipv4_type);
  81. }
  82. static void __exit nft_dup_ipv4_module_exit(void)
  83. {
  84. nft_unregister_expr(&nft_dup_ipv4_type);
  85. }
  86. module_init(nft_dup_ipv4_module_init);
  87. module_exit(nft_dup_ipv4_module_exit);
  88. MODULE_LICENSE("GPL");
  89. MODULE_AUTHOR("Pablo Neira Ayuso <pablo@netfilter.org>");
  90. MODULE_ALIAS_NFT_AF_EXPR(AF_INET, "dup");
  91. MODULE_DESCRIPTION("IPv4 nftables packet duplication support");