1 /* SPDX-License-Identifier: GPL-2.0 */ 2 #include <linux/module.h> 3 #include <linux/netfilter/nf_tables.h> 4 #include <net/netfilter/nf_tables.h> 5 #include <net/netfilter/nf_tables_core.h> 6 #include <net/netfilter/nf_socket.h> 7 #include <net/inet_sock.h> 8 #include <net/tcp.h> 9 10 struct nft_socket { 11 enum nft_socket_keys key:8; 12 union { 13 enum nft_registers dreg:8; 14 }; 15 }; 16 17 static void nft_socket_eval(const struct nft_expr *expr, 18 struct nft_regs *regs, 19 const struct nft_pktinfo *pkt) 20 { 21 const struct nft_socket *priv = nft_expr_priv(expr); 22 struct sk_buff *skb = pkt->skb; 23 struct sock *sk = skb->sk; 24 u32 *dest = ®s->data[priv->dreg]; 25 26 if (sk && !net_eq(nft_net(pkt), sock_net(sk))) 27 sk = NULL; 28 29 if (!sk) 30 switch(nft_pf(pkt)) { 31 case NFPROTO_IPV4: 32 sk = nf_sk_lookup_slow_v4(nft_net(pkt), skb, nft_in(pkt)); 33 break; 34 #if IS_ENABLED(CONFIG_NF_TABLES_IPV6) 35 case NFPROTO_IPV6: 36 sk = nf_sk_lookup_slow_v6(nft_net(pkt), skb, nft_in(pkt)); 37 break; 38 #endif 39 default: 40 WARN_ON_ONCE(1); 41 regs->verdict.code = NFT_BREAK; 42 return; 43 } 44 45 if (!sk) { 46 nft_reg_store8(dest, 0); 47 return; 48 } 49 50 /* So that subsequent socket matching not to require other lookups. */ 51 skb->sk = sk; 52 53 switch(priv->key) { 54 case NFT_SOCKET_TRANSPARENT: 55 nft_reg_store8(dest, inet_sk_transparent(sk)); 56 break; 57 default: 58 WARN_ON(1); 59 regs->verdict.code = NFT_BREAK; 60 } 61 } 62 63 static const struct nla_policy nft_socket_policy[NFTA_SOCKET_MAX + 1] = { 64 [NFTA_SOCKET_KEY] = { .type = NLA_U32 }, 65 [NFTA_SOCKET_DREG] = { .type = NLA_U32 }, 66 }; 67 68 static int nft_socket_init(const struct nft_ctx *ctx, 69 const struct nft_expr *expr, 70 const struct nlattr * const tb[]) 71 { 72 struct nft_socket *priv = nft_expr_priv(expr); 73 unsigned int len; 74 75 if (!tb[NFTA_SOCKET_DREG] || !tb[NFTA_SOCKET_KEY]) 76 return -EINVAL; 77 78 switch(ctx->family) { 79 case NFPROTO_IPV4: 80 #if IS_ENABLED(CONFIG_NF_TABLES_IPV6) 81 case NFPROTO_IPV6: 82 #endif 83 case NFPROTO_INET: 84 break; 85 default: 86 return -EOPNOTSUPP; 87 } 88 89 priv->key = ntohl(nla_get_u32(tb[NFTA_SOCKET_KEY])); 90 switch(priv->key) { 91 case NFT_SOCKET_TRANSPARENT: 92 len = sizeof(u8); 93 break; 94 default: 95 return -EOPNOTSUPP; 96 } 97 98 priv->dreg = nft_parse_register(tb[NFTA_SOCKET_DREG]); 99 return nft_validate_register_store(ctx, priv->dreg, NULL, 100 NFT_DATA_VALUE, len); 101 } 102 103 static int nft_socket_dump(struct sk_buff *skb, 104 const struct nft_expr *expr) 105 { 106 const struct nft_socket *priv = nft_expr_priv(expr); 107 108 if (nla_put_u32(skb, NFTA_SOCKET_KEY, htonl(priv->key))) 109 return -1; 110 if (nft_dump_register(skb, NFTA_SOCKET_DREG, priv->dreg)) 111 return -1; 112 return 0; 113 } 114 115 static struct nft_expr_type nft_socket_type; 116 static const struct nft_expr_ops nft_socket_ops = { 117 .type = &nft_socket_type, 118 .size = NFT_EXPR_SIZE(sizeof(struct nft_socket)), 119 .eval = nft_socket_eval, 120 .init = nft_socket_init, 121 .dump = nft_socket_dump, 122 }; 123 124 static struct nft_expr_type nft_socket_type __read_mostly = { 125 .name = "socket", 126 .ops = &nft_socket_ops, 127 .policy = nft_socket_policy, 128 .maxattr = NFTA_SOCKET_MAX, 129 .owner = THIS_MODULE, 130 }; 131 132 static int __init nft_socket_module_init(void) 133 { 134 return nft_register_expr(&nft_socket_type); 135 } 136 137 static void __exit nft_socket_module_exit(void) 138 { 139 nft_unregister_expr(&nft_socket_type); 140 } 141 142 module_init(nft_socket_module_init); 143 module_exit(nft_socket_module_exit); 144 145 MODULE_LICENSE("GPL"); 146 MODULE_AUTHOR("Máté Eckl"); 147 MODULE_DESCRIPTION("nf_tables socket match module"); 148 MODULE_ALIAS_NFT_EXPR("socket"); 149