1 /* 2 * Copyright (c) 2015 Pablo Neira Ayuso <pablo@netfilter.org> 3 * 4 * This program is free software; you can redistribute it and/or modify it 5 * under the terms of the GNU General Public License version 2 as published by 6 * the Free Software Foundation. 7 */ 8 9 #include <linux/kernel.h> 10 #include <linux/init.h> 11 #include <linux/module.h> 12 #include <linux/netlink.h> 13 #include <linux/netfilter.h> 14 #include <linux/netfilter/nf_tables.h> 15 #include <net/netfilter/nf_tables.h> 16 #include <net/netfilter/ipv4/nf_dup_ipv4.h> 17 18 struct nft_dup_ipv4 { 19 enum nft_registers sreg_addr:8; 20 enum nft_registers sreg_dev:8; 21 }; 22 23 static void nft_dup_ipv4_eval(const struct nft_expr *expr, 24 struct nft_regs *regs, 25 const struct nft_pktinfo *pkt) 26 { 27 struct nft_dup_ipv4 *priv = nft_expr_priv(expr); 28 struct in_addr gw = { 29 .s_addr = (__force __be32)regs->data[priv->sreg_addr], 30 }; 31 int oif = priv->sreg_dev ? regs->data[priv->sreg_dev] : -1; 32 33 nf_dup_ipv4(nft_net(pkt), pkt->skb, nft_hook(pkt), &gw, oif); 34 } 35 36 static int nft_dup_ipv4_init(const struct nft_ctx *ctx, 37 const struct nft_expr *expr, 38 const struct nlattr * const tb[]) 39 { 40 struct nft_dup_ipv4 *priv = nft_expr_priv(expr); 41 int err; 42 43 if (tb[NFTA_DUP_SREG_ADDR] == NULL) 44 return -EINVAL; 45 46 priv->sreg_addr = nft_parse_register(tb[NFTA_DUP_SREG_ADDR]); 47 err = nft_validate_register_load(priv->sreg_addr, sizeof(struct in_addr)); 48 if (err < 0) 49 return err; 50 51 if (tb[NFTA_DUP_SREG_DEV] != NULL) { 52 priv->sreg_dev = nft_parse_register(tb[NFTA_DUP_SREG_DEV]); 53 return nft_validate_register_load(priv->sreg_dev, sizeof(int)); 54 } 55 return 0; 56 } 57 58 static int nft_dup_ipv4_dump(struct sk_buff *skb, const struct nft_expr *expr) 59 { 60 struct nft_dup_ipv4 *priv = nft_expr_priv(expr); 61 62 if (nft_dump_register(skb, NFTA_DUP_SREG_ADDR, priv->sreg_addr)) 63 goto nla_put_failure; 64 if (priv->sreg_dev && 65 nft_dump_register(skb, NFTA_DUP_SREG_DEV, priv->sreg_dev)) 66 goto nla_put_failure; 67 68 return 0; 69 70 nla_put_failure: 71 return -1; 72 } 73 74 static struct nft_expr_type nft_dup_ipv4_type; 75 static const struct nft_expr_ops nft_dup_ipv4_ops = { 76 .type = &nft_dup_ipv4_type, 77 .size = NFT_EXPR_SIZE(sizeof(struct nft_dup_ipv4)), 78 .eval = nft_dup_ipv4_eval, 79 .init = nft_dup_ipv4_init, 80 .dump = nft_dup_ipv4_dump, 81 }; 82 83 static const struct nla_policy nft_dup_ipv4_policy[NFTA_DUP_MAX + 1] = { 84 [NFTA_DUP_SREG_ADDR] = { .type = NLA_U32 }, 85 [NFTA_DUP_SREG_DEV] = { .type = NLA_U32 }, 86 }; 87 88 static struct nft_expr_type nft_dup_ipv4_type __read_mostly = { 89 .family = NFPROTO_IPV4, 90 .name = "dup", 91 .ops = &nft_dup_ipv4_ops, 92 .policy = nft_dup_ipv4_policy, 93 .maxattr = NFTA_DUP_MAX, 94 .owner = THIS_MODULE, 95 }; 96 97 static int __init nft_dup_ipv4_module_init(void) 98 { 99 return nft_register_expr(&nft_dup_ipv4_type); 100 } 101 102 static void __exit nft_dup_ipv4_module_exit(void) 103 { 104 nft_unregister_expr(&nft_dup_ipv4_type); 105 } 106 107 module_init(nft_dup_ipv4_module_init); 108 module_exit(nft_dup_ipv4_module_exit); 109 110 MODULE_LICENSE("GPL"); 111 MODULE_AUTHOR("Pablo Neira Ayuso <pablo@netfilter.org>"); 112 MODULE_ALIAS_NFT_AF_EXPR(AF_INET, "dup"); 113