KOVACS Krisztian | 9ad2d74 | 2008-10-08 11:35:12 +0200 | [diff] [blame] | 1 | #ifndef _NF_TPROXY_CORE_H |
| 2 | #define _NF_TPROXY_CORE_H |
| 3 | |
| 4 | #include <linux/types.h> |
| 5 | #include <linux/in.h> |
| 6 | #include <linux/skbuff.h> |
| 7 | #include <net/sock.h> |
Balazs Scheidler | 3b9afb2 | 2010-10-21 16:12:14 +0200 | [diff] [blame] | 8 | #include <net/inet_hashtables.h> |
| 9 | #include <net/inet6_hashtables.h> |
KOVACS Krisztian | 9ad2d74 | 2008-10-08 11:35:12 +0200 | [diff] [blame] | 10 | #include <net/tcp.h> |
| 11 | |
Balazs Scheidler | 106e4c2 | 2010-10-21 12:45:14 +0200 | [diff] [blame] | 12 | #define NFT_LOOKUP_ANY 0 |
| 13 | #define NFT_LOOKUP_LISTENER 1 |
| 14 | #define NFT_LOOKUP_ESTABLISHED 2 |
| 15 | |
KOVACS Krisztian | 9ad2d74 | 2008-10-08 11:35:12 +0200 | [diff] [blame] | 16 | /* look up and get a reference to a matching socket */ |
Balazs Scheidler | 6006db8 | 2010-10-21 12:47:34 +0200 | [diff] [blame] | 17 | |
| 18 | |
| 19 | /* This function is used by the 'TPROXY' target and the 'socket' |
| 20 | * match. The following lookups are supported: |
| 21 | * |
| 22 | * Explicit TProxy target rule |
| 23 | * =========================== |
| 24 | * |
| 25 | * This is used when the user wants to intercept a connection matching |
| 26 | * an explicit iptables rule. In this case the sockets are assumed |
| 27 | * matching in preference order: |
| 28 | * |
| 29 | * - match: if there's a fully established connection matching the |
| 30 | * _packet_ tuple, it is returned, assuming the redirection |
| 31 | * already took place and we process a packet belonging to an |
| 32 | * established connection |
| 33 | * |
| 34 | * - match: if there's a listening socket matching the redirection |
| 35 | * (e.g. on-port & on-ip of the connection), it is returned, |
| 36 | * regardless if it was bound to 0.0.0.0 or an explicit |
| 37 | * address. The reasoning is that if there's an explicit rule, it |
| 38 | * does not really matter if the listener is bound to an interface |
| 39 | * or to 0. The user already stated that he wants redirection |
| 40 | * (since he added the rule). |
| 41 | * |
| 42 | * "socket" match based redirection (no specific rule) |
| 43 | * =================================================== |
| 44 | * |
| 45 | * There are connections with dynamic endpoints (e.g. FTP data |
| 46 | * connection) that the user is unable to add explicit rules |
| 47 | * for. These are taken care of by a generic "socket" rule. It is |
| 48 | * assumed that the proxy application is trusted to open such |
| 49 | * connections without explicit iptables rule (except of course the |
| 50 | * generic 'socket' rule). In this case the following sockets are |
| 51 | * matched in preference order: |
| 52 | * |
| 53 | * - match: if there's a fully established connection matching the |
| 54 | * _packet_ tuple |
| 55 | * |
| 56 | * - match: if there's a non-zero bound listener (possibly with a |
| 57 | * non-local address) We don't accept zero-bound listeners, since |
| 58 | * then local services could intercept traffic going through the |
| 59 | * box. |
| 60 | * |
| 61 | * Please note that there's an overlap between what a TPROXY target |
| 62 | * and a socket match will match. Normally if you have both rules the |
| 63 | * "socket" match will be the first one, effectively all packets |
| 64 | * belonging to established connections going through that one. |
| 65 | */ |
| 66 | static inline struct sock * |
KOVACS Krisztian | 9ad2d74 | 2008-10-08 11:35:12 +0200 | [diff] [blame] | 67 | nf_tproxy_get_sock_v4(struct net *net, const u8 protocol, |
| 68 | const __be32 saddr, const __be32 daddr, |
| 69 | const __be16 sport, const __be16 dport, |
Balazs Scheidler | 6006db8 | 2010-10-21 12:47:34 +0200 | [diff] [blame] | 70 | const struct net_device *in, int lookup_type) |
| 71 | { |
| 72 | struct sock *sk; |
| 73 | |
| 74 | /* look up socket */ |
| 75 | switch (protocol) { |
| 76 | case IPPROTO_TCP: |
| 77 | switch (lookup_type) { |
| 78 | case NFT_LOOKUP_ANY: |
| 79 | sk = __inet_lookup(net, &tcp_hashinfo, |
| 80 | saddr, sport, daddr, dport, |
| 81 | in->ifindex); |
| 82 | break; |
| 83 | case NFT_LOOKUP_LISTENER: |
| 84 | sk = inet_lookup_listener(net, &tcp_hashinfo, |
| 85 | daddr, dport, |
| 86 | in->ifindex); |
| 87 | |
| 88 | /* NOTE: we return listeners even if bound to |
| 89 | * 0.0.0.0, those are filtered out in |
| 90 | * xt_socket, since xt_TPROXY needs 0 bound |
| 91 | * listeners too */ |
| 92 | |
| 93 | break; |
| 94 | case NFT_LOOKUP_ESTABLISHED: |
| 95 | sk = inet_lookup_established(net, &tcp_hashinfo, |
| 96 | saddr, sport, daddr, dport, |
| 97 | in->ifindex); |
| 98 | break; |
| 99 | default: |
| 100 | WARN_ON(1); |
| 101 | sk = NULL; |
| 102 | break; |
| 103 | } |
| 104 | break; |
| 105 | case IPPROTO_UDP: |
| 106 | sk = udp4_lib_lookup(net, saddr, sport, daddr, dport, |
| 107 | in->ifindex); |
| 108 | if (sk && lookup_type != NFT_LOOKUP_ANY) { |
| 109 | int connected = (sk->sk_state == TCP_ESTABLISHED); |
| 110 | int wildcard = (inet_sk(sk)->inet_rcv_saddr == 0); |
| 111 | |
| 112 | /* NOTE: we return listeners even if bound to |
| 113 | * 0.0.0.0, those are filtered out in |
| 114 | * xt_socket, since xt_TPROXY needs 0 bound |
| 115 | * listeners too */ |
| 116 | if ((lookup_type == NFT_LOOKUP_ESTABLISHED && (!connected || wildcard)) || |
| 117 | (lookup_type == NFT_LOOKUP_LISTENER && connected)) { |
| 118 | sock_put(sk); |
| 119 | sk = NULL; |
| 120 | } |
| 121 | } |
| 122 | break; |
| 123 | default: |
| 124 | WARN_ON(1); |
| 125 | sk = NULL; |
| 126 | } |
| 127 | |
| 128 | pr_debug("tproxy socket lookup: proto %u %08x:%u -> %08x:%u, lookup type: %d, sock %p\n", |
| 129 | protocol, ntohl(saddr), ntohs(sport), ntohl(daddr), ntohs(dport), lookup_type, sk); |
| 130 | |
| 131 | return sk; |
| 132 | } |
| 133 | |
Balazs Scheidler | 3b9afb2 | 2010-10-21 16:12:14 +0200 | [diff] [blame] | 134 | #if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE) |
| 135 | static inline struct sock * |
| 136 | nf_tproxy_get_sock_v6(struct net *net, const u8 protocol, |
| 137 | const struct in6_addr *saddr, const struct in6_addr *daddr, |
| 138 | const __be16 sport, const __be16 dport, |
| 139 | const struct net_device *in, int lookup_type) |
| 140 | { |
| 141 | struct sock *sk; |
| 142 | |
| 143 | /* look up socket */ |
| 144 | switch (protocol) { |
| 145 | case IPPROTO_TCP: |
| 146 | switch (lookup_type) { |
| 147 | case NFT_LOOKUP_ANY: |
| 148 | sk = inet6_lookup(net, &tcp_hashinfo, |
| 149 | saddr, sport, daddr, dport, |
| 150 | in->ifindex); |
| 151 | break; |
| 152 | case NFT_LOOKUP_LISTENER: |
| 153 | sk = inet6_lookup_listener(net, &tcp_hashinfo, |
| 154 | daddr, ntohs(dport), |
| 155 | in->ifindex); |
| 156 | |
| 157 | /* NOTE: we return listeners even if bound to |
| 158 | * 0.0.0.0, those are filtered out in |
| 159 | * xt_socket, since xt_TPROXY needs 0 bound |
| 160 | * listeners too */ |
| 161 | |
| 162 | break; |
| 163 | case NFT_LOOKUP_ESTABLISHED: |
| 164 | sk = __inet6_lookup_established(net, &tcp_hashinfo, |
| 165 | saddr, sport, daddr, ntohs(dport), |
| 166 | in->ifindex); |
| 167 | break; |
| 168 | default: |
| 169 | WARN_ON(1); |
| 170 | sk = NULL; |
| 171 | break; |
| 172 | } |
| 173 | break; |
| 174 | case IPPROTO_UDP: |
| 175 | sk = udp6_lib_lookup(net, saddr, sport, daddr, dport, |
| 176 | in->ifindex); |
| 177 | if (sk && lookup_type != NFT_LOOKUP_ANY) { |
| 178 | int connected = (sk->sk_state == TCP_ESTABLISHED); |
| 179 | int wildcard = ipv6_addr_any(&inet6_sk(sk)->rcv_saddr); |
| 180 | |
| 181 | /* NOTE: we return listeners even if bound to |
| 182 | * 0.0.0.0, those are filtered out in |
| 183 | * xt_socket, since xt_TPROXY needs 0 bound |
| 184 | * listeners too */ |
| 185 | if ((lookup_type == NFT_LOOKUP_ESTABLISHED && (!connected || wildcard)) || |
| 186 | (lookup_type == NFT_LOOKUP_LISTENER && connected)) { |
| 187 | sock_put(sk); |
| 188 | sk = NULL; |
| 189 | } |
| 190 | } |
| 191 | break; |
| 192 | default: |
| 193 | WARN_ON(1); |
| 194 | sk = NULL; |
| 195 | } |
| 196 | |
| 197 | pr_debug("tproxy socket lookup: proto %u %pI6:%u -> %pI6:%u, lookup type: %d, sock %p\n", |
| 198 | protocol, saddr, ntohs(sport), daddr, ntohs(dport), lookup_type, sk); |
| 199 | |
| 200 | return sk; |
| 201 | } |
| 202 | #endif |
KOVACS Krisztian | 9ad2d74 | 2008-10-08 11:35:12 +0200 | [diff] [blame] | 203 | |
KOVACS Krisztian | 9ad2d74 | 2008-10-08 11:35:12 +0200 | [diff] [blame] | 204 | /* assign a socket to the skb -- consumes sk */ |
Florian Westphal | d503b30 | 2011-02-17 11:32:38 +0100 | [diff] [blame] | 205 | void |
KOVACS Krisztian | 9ad2d74 | 2008-10-08 11:35:12 +0200 | [diff] [blame] | 206 | nf_tproxy_assign_sock(struct sk_buff *skb, struct sock *sk); |
| 207 | |
| 208 | #endif |