1 #include <net/netfilter/nf_tproxy.h>
2 #include <linux/module.h>
3 #include <net/inet6_hashtables.h>
4 #include <net/addrconf.h>
5 #include <net/udp.h>
6 #include <net/tcp.h>
7
8 const struct in6_addr *
nf_tproxy_laddr6(struct sk_buff * skb,const struct in6_addr * user_laddr,const struct in6_addr * daddr)9 nf_tproxy_laddr6(struct sk_buff *skb, const struct in6_addr *user_laddr,
10 const struct in6_addr *daddr)
11 {
12 struct inet6_dev *indev;
13 struct inet6_ifaddr *ifa;
14 struct in6_addr *laddr;
15
16 if (!ipv6_addr_any(user_laddr))
17 return user_laddr;
18 laddr = NULL;
19
20 indev = __in6_dev_get(skb->dev);
21 if (indev) {
22 read_lock_bh(&indev->lock);
23 list_for_each_entry(ifa, &indev->addr_list, if_list) {
24 if (ifa->flags & (IFA_F_TENTATIVE | IFA_F_DEPRECATED))
25 continue;
26
27 laddr = &ifa->addr;
28 break;
29 }
30 read_unlock_bh(&indev->lock);
31 }
32
33 return laddr ? laddr : daddr;
34 }
35 EXPORT_SYMBOL_GPL(nf_tproxy_laddr6);
36
37 struct sock *
nf_tproxy_handle_time_wait6(struct sk_buff * skb,int tproto,int thoff,struct net * net,const struct in6_addr * laddr,const __be16 lport,struct sock * sk)38 nf_tproxy_handle_time_wait6(struct sk_buff *skb, int tproto, int thoff,
39 struct net *net,
40 const struct in6_addr *laddr,
41 const __be16 lport,
42 struct sock *sk)
43 {
44 const struct ipv6hdr *iph = ipv6_hdr(skb);
45 struct tcphdr _hdr, *hp;
46
47 hp = skb_header_pointer(skb, thoff, sizeof(_hdr), &_hdr);
48 if (hp == NULL) {
49 inet_twsk_put(inet_twsk(sk));
50 return NULL;
51 }
52
53 if (hp->syn && !hp->rst && !hp->ack && !hp->fin) {
54 /* SYN to a TIME_WAIT socket, we'd rather redirect it
55 * to a listener socket if there's one */
56 struct sock *sk2;
57
58 sk2 = nf_tproxy_get_sock_v6(net, skb, thoff, tproto,
59 &iph->saddr,
60 nf_tproxy_laddr6(skb, laddr, &iph->daddr),
61 hp->source,
62 lport ? lport : hp->dest,
63 skb->dev, NF_TPROXY_LOOKUP_LISTENER);
64 if (sk2) {
65 inet_twsk_deschedule_put(inet_twsk(sk));
66 sk = sk2;
67 }
68 }
69
70 return sk;
71 }
72 EXPORT_SYMBOL_GPL(nf_tproxy_handle_time_wait6);
73
74 struct sock *
nf_tproxy_get_sock_v6(struct net * net,struct sk_buff * skb,int thoff,const u8 protocol,const struct in6_addr * saddr,const struct in6_addr * daddr,const __be16 sport,const __be16 dport,const struct net_device * in,const enum nf_tproxy_lookup_t lookup_type)75 nf_tproxy_get_sock_v6(struct net *net, struct sk_buff *skb, int thoff,
76 const u8 protocol,
77 const struct in6_addr *saddr, const struct in6_addr *daddr,
78 const __be16 sport, const __be16 dport,
79 const struct net_device *in,
80 const enum nf_tproxy_lookup_t lookup_type)
81 {
82 struct sock *sk;
83
84 switch (protocol) {
85 case IPPROTO_TCP: {
86 struct tcphdr _hdr, *hp;
87
88 hp = skb_header_pointer(skb, thoff,
89 sizeof(struct tcphdr), &_hdr);
90 if (hp == NULL)
91 return NULL;
92
93 switch (lookup_type) {
94 case NF_TPROXY_LOOKUP_LISTENER:
95 sk = inet6_lookup_listener(net, &tcp_hashinfo, skb,
96 thoff + __tcp_hdrlen(hp),
97 saddr, sport,
98 daddr, ntohs(dport),
99 in->ifindex, 0);
100
101 if (sk && !refcount_inc_not_zero(&sk->sk_refcnt))
102 sk = NULL;
103 /* NOTE: we return listeners even if bound to
104 * 0.0.0.0, those are filtered out in
105 * xt_socket, since xt_TPROXY needs 0 bound
106 * listeners too
107 */
108 break;
109 case NF_TPROXY_LOOKUP_ESTABLISHED:
110 sk = __inet6_lookup_established(net, &tcp_hashinfo,
111 saddr, sport, daddr, ntohs(dport),
112 in->ifindex, 0);
113 break;
114 default:
115 BUG();
116 }
117 break;
118 }
119 case IPPROTO_UDP:
120 sk = udp6_lib_lookup(net, saddr, sport, daddr, dport,
121 in->ifindex);
122 if (sk) {
123 int connected = (sk->sk_state == TCP_ESTABLISHED);
124 int wildcard = ipv6_addr_any(&sk->sk_v6_rcv_saddr);
125
126 /* NOTE: we return listeners even if bound to
127 * 0.0.0.0, those are filtered out in
128 * xt_socket, since xt_TPROXY needs 0 bound
129 * listeners too
130 */
131 if ((lookup_type == NF_TPROXY_LOOKUP_ESTABLISHED && (!connected || wildcard)) ||
132 (lookup_type == NF_TPROXY_LOOKUP_LISTENER && connected)) {
133 sock_put(sk);
134 sk = NULL;
135 }
136 }
137 break;
138 default:
139 WARN_ON(1);
140 sk = NULL;
141 }
142
143 pr_debug("tproxy socket lookup: proto %u %pI6:%u -> %pI6:%u, lookup type: %d, sock %p\n",
144 protocol, saddr, ntohs(sport), daddr, ntohs(dport), lookup_type, sk);
145
146 return sk;
147 }
148 EXPORT_SYMBOL_GPL(nf_tproxy_get_sock_v6);
149
150 MODULE_LICENSE("GPL");
151 MODULE_AUTHOR("Balazs Scheidler, Krisztian Kovacs");
152 MODULE_DESCRIPTION("Netfilter IPv4 transparent proxy support");
153
