From 8db4c5be88f62ffd7a552f70687a10c614dc697b Mon Sep 17 00:00:00 2001 From: Pablo Neira Ayuso Date: Thu, 27 Oct 2016 19:49:48 +0100 Subject: netfilter: move socket lookup infrastructure to nf_socket_ipv{4,6}.c We need this split to reuse existing codebase for the upcoming nf_tables socket expression. Signed-off-by: Pablo Neira Ayuso --- net/ipv4/netfilter/nf_socket_ipv4.c | 163 ++++++++++++++++++++++++++++++++++++ 1 file changed, 163 insertions(+) create mode 100644 net/ipv4/netfilter/nf_socket_ipv4.c (limited to 'net/ipv4/netfilter/nf_socket_ipv4.c') diff --git a/net/ipv4/netfilter/nf_socket_ipv4.c b/net/ipv4/netfilter/nf_socket_ipv4.c new file mode 100644 index 000000000000..a83d558e1aae --- /dev/null +++ b/net/ipv4/netfilter/nf_socket_ipv4.c @@ -0,0 +1,163 @@ +/* + * Copyright (C) 2007-2008 BalaBit IT Ltd. + * Author: Krisztian Kovacs + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + * + */ +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt +#include +#include +#include +#include +#include +#include +#include +#include +#if IS_ENABLED(CONFIG_NF_CONNTRACK) +#include +#endif + +static int +extract_icmp4_fields(const struct sk_buff *skb, u8 *protocol, + __be32 *raddr, __be32 *laddr, + __be16 *rport, __be16 *lport) +{ + unsigned int outside_hdrlen = ip_hdrlen(skb); + struct iphdr *inside_iph, _inside_iph; + struct icmphdr *icmph, _icmph; + __be16 *ports, _ports[2]; + + icmph = skb_header_pointer(skb, outside_hdrlen, + sizeof(_icmph), &_icmph); + if (icmph == NULL) + return 1; + + switch (icmph->type) { + case ICMP_DEST_UNREACH: + case ICMP_SOURCE_QUENCH: + case ICMP_REDIRECT: + case ICMP_TIME_EXCEEDED: + case ICMP_PARAMETERPROB: + break; + default: + return 1; + } + + inside_iph = skb_header_pointer(skb, outside_hdrlen + + sizeof(struct icmphdr), + sizeof(_inside_iph), &_inside_iph); + if (inside_iph == NULL) + return 1; + + if (inside_iph->protocol != IPPROTO_TCP && + inside_iph->protocol != IPPROTO_UDP) + return 1; + + ports = skb_header_pointer(skb, outside_hdrlen + + sizeof(struct icmphdr) + + (inside_iph->ihl << 2), + sizeof(_ports), &_ports); + if (ports == NULL) + return 1; + + /* the inside IP packet is the one quoted from our side, thus + * its saddr is the local address */ + *protocol = inside_iph->protocol; + *laddr = inside_iph->saddr; + *lport = ports[0]; + *raddr = inside_iph->daddr; + *rport = ports[1]; + + return 0; +} + +static struct sock * +nf_socket_get_sock_v4(struct net *net, struct sk_buff *skb, const int doff, + const u8 protocol, + const __be32 saddr, const __be32 daddr, + const __be16 sport, const __be16 dport, + const struct net_device *in) +{ + switch (protocol) { + case IPPROTO_TCP: + return inet_lookup(net, &tcp_hashinfo, skb, doff, + saddr, sport, daddr, dport, + in->ifindex); + case IPPROTO_UDP: + return udp4_lib_lookup(net, saddr, sport, daddr, dport, + in->ifindex); + } + return NULL; +} + +struct sock *nf_sk_lookup_slow_v4(struct net *net, const struct sk_buff *skb, + const struct net_device *indev) +{ + __be32 uninitialized_var(daddr), uninitialized_var(saddr); + __be16 uninitialized_var(dport), uninitialized_var(sport); + const struct iphdr *iph = ip_hdr(skb); + struct sk_buff *data_skb = NULL; + u8 uninitialized_var(protocol); +#if IS_ENABLED(CONFIG_NF_CONNTRACK) + enum ip_conntrack_info ctinfo; + struct nf_conn const *ct; +#endif + int doff = 0; + + if (iph->protocol == IPPROTO_UDP || iph->protocol == IPPROTO_TCP) { + struct udphdr _hdr, *hp; + + hp = skb_header_pointer(skb, ip_hdrlen(skb), + sizeof(_hdr), &_hdr); + if (hp == NULL) + return NULL; + + protocol = iph->protocol; + saddr = iph->saddr; + sport = hp->source; + daddr = iph->daddr; + dport = hp->dest; + data_skb = (struct sk_buff *)skb; + doff = iph->protocol == IPPROTO_TCP ? + ip_hdrlen(skb) + __tcp_hdrlen((struct tcphdr *)hp) : + ip_hdrlen(skb) + sizeof(*hp); + + } else if (iph->protocol == IPPROTO_ICMP) { + if (extract_icmp4_fields(skb, &protocol, &saddr, &daddr, + &sport, &dport)) + return NULL; + } else { + return NULL; + } + +#if IS_ENABLED(CONFIG_NF_CONNTRACK) + /* Do the lookup with the original socket address in + * case this is a reply packet of an established + * SNAT-ted connection. + */ + ct = nf_ct_get(skb, &ctinfo); + if (ct && !nf_ct_is_untracked(ct) && + ((iph->protocol != IPPROTO_ICMP && + ctinfo == IP_CT_ESTABLISHED_REPLY) || + (iph->protocol == IPPROTO_ICMP && + ctinfo == IP_CT_RELATED_REPLY)) && + (ct->status & IPS_SRC_NAT_DONE)) { + + daddr = ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.src.u3.ip; + dport = (iph->protocol == IPPROTO_TCP) ? + ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.src.u.tcp.port : + ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.src.u.udp.port; + } +#endif + + return nf_socket_get_sock_v4(net, data_skb, doff, protocol, saddr, + daddr, sport, dport, indev); +} +EXPORT_SYMBOL_GPL(nf_sk_lookup_slow_v4); + +MODULE_LICENSE("GPL"); +MODULE_AUTHOR("Krisztian Kovacs, Balazs Scheidler"); +MODULE_DESCRIPTION("Netfilter IPv4 socket lookup infrastructure"); -- cgit v1.2.3-59-g8ed1b