// SPDX-License-Identifier: GPL-2.0-only /* * Copyright (C) 2007-2008 BalaBit IT Ltd. * Author: Krisztian Kovacs */ #include #include #include #include #include #include #include #include #include #include struct sock * nf_tproxy_handle_time_wait4(struct net *net, struct sk_buff *skb, __be32 laddr, __be16 lport, struct sock *sk) { const struct iphdr *iph = ip_hdr(skb); struct tcphdr _hdr, *hp; hp = skb_header_pointer(skb, ip_hdrlen(skb), sizeof(_hdr), &_hdr); if (hp == NULL) { inet_twsk_put(inet_twsk(sk)); return NULL; } if (hp->syn && !hp->rst && !hp->ack && !hp->fin) { /* SYN to a TIME_WAIT socket, we'd rather redirect it * to a listener socket if there's one */ struct sock *sk2; sk2 = nf_tproxy_get_sock_v4(net, skb, iph->protocol, iph->saddr, laddr ? laddr : iph->daddr, hp->source, lport ? lport : hp->dest, skb->dev, NF_TPROXY_LOOKUP_LISTENER); if (sk2) { inet_twsk_deschedule_put(inet_twsk(sk)); sk = sk2; } } return sk; } EXPORT_SYMBOL_GPL(nf_tproxy_handle_time_wait4); __be32 nf_tproxy_laddr4(struct sk_buff *skb, __be32 user_laddr, __be32 daddr) { const struct in_ifaddr *ifa; struct in_device *indev; __be32 laddr; if (user_laddr) return user_laddr; laddr = 0; indev = __in_dev_get_rcu(skb->dev); in_dev_for_each_ifa_rcu(ifa, indev) { if (ifa->ifa_flags & IFA_F_SECONDARY) continue; laddr = ifa->ifa_local; break; } return laddr ? laddr : daddr; } EXPORT_SYMBOL_GPL(nf_tproxy_laddr4); struct sock * nf_tproxy_get_sock_v4(struct net *net, struct sk_buff *skb, const u8 protocol, const __be32 saddr, const __be32 daddr, const __be16 sport, const __be16 dport, const struct net_device *in, const enum nf_tproxy_lookup_t lookup_type) { struct sock *sk; switch (protocol) { case IPPROTO_TCP: { struct tcphdr _hdr, *hp; hp = skb_header_pointer(skb, ip_hdrlen(skb), sizeof(struct tcphdr), &_hdr); if (hp == NULL) return NULL; switch (lookup_type) { case NF_TPROXY_LOOKUP_LISTENER: sk = inet_lookup_listener(net, &tcp_hashinfo, skb, ip_hdrlen(skb) + __tcp_hdrlen(hp), saddr, sport, daddr, dport, in->ifindex, 0); if (sk && !refcount_inc_not_zero(&sk->sk_refcnt)) sk = NULL; /* NOTE: we return listeners even if bound to * 0.0.0.0, those are filtered out in * xt_socket, since xt_TPROXY needs 0 bound * listeners too */ break; case NF_TPROXY_LOOKUP_ESTABLISHED: sk = inet_lookup_established(net, &tcp_hashinfo, saddr, sport, daddr, dport, in->ifindex); break; default: BUG(); } break; } case IPPROTO_UDP: sk = udp4_lib_lookup(net, saddr, sport, daddr, dport, in->ifindex); if (sk) { int connected = (sk->sk_state == TCP_ESTABLISHED); int wildcard = (inet_sk(sk)->inet_rcv_saddr == 0); /* NOTE: we return listeners even if bound to * 0.0.0.0, those are filtered out in * xt_socket, since xt_TPROXY needs 0 bound * listeners too */ if ((lookup_type == NF_TPROXY_LOOKUP_ESTABLISHED && (!connected || wildcard)) || (lookup_type == NF_TPROXY_LOOKUP_LISTENER && connected)) { sock_put(sk); sk = NULL; } } break; default: WARN_ON(1); sk = NULL; } pr_debug("tproxy socket lookup: proto %u %08x:%u -> %08x:%u, lookup type: %d, sock %p\n", protocol, ntohl(saddr), ntohs(sport), ntohl(daddr), ntohs(dport), lookup_type, sk); return sk; } EXPORT_SYMBOL_GPL(nf_tproxy_get_sock_v4); MODULE_LICENSE("GPL"); MODULE_AUTHOR("Balazs Scheidler, Krisztian Kovacs"); MODULE_DESCRIPTION("Netfilter IPv4 transparent proxy support");