LXR linux/net/ipv6/netfilter/nf_tproxy

   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
   8const struct in6_addr *
   9nf_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}
  35EXPORT_SYMBOL_GPL(nf_tproxy_laddr6);
  36
  37struct sock *
  38nf_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}
  72EXPORT_SYMBOL_GPL(nf_tproxy_handle_time_wait6);
  73
  74struct sock *
  75nf_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}
 148EXPORT_SYMBOL_GPL(nf_tproxy_get_sock_v6);
 149
 150MODULE_LICENSE("GPL");
 151MODULE_AUTHOR("Balazs Scheidler, Krisztian Kovacs");
 152MODULE_DESCRIPTION("Netfilter IPv4 transparent proxy support");
 153