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// SPDX-License-Identifier: GPL-2.0-only
/*
* Copyright (C) 2007-2008 BalaBit IT Ltd.
* Author: Krisztian Kovacs
*/
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/module.h>
#include <linux/skbuff.h>
#include <net/tcp.h>
#include <net/udp.h>
#include <net/icmp.h>
#include <net/sock.h>
#include <net/inet_sock.h>
#include <net/inet6_hashtables.h>
#include <net/netfilter/ipv6/nf_defrag_ipv6.h>
#include <net/netfilter/nf_socket.h>
#if IS_ENABLED(CONFIG_NF_CONNTRACK)
#include <net/netfilter/nf_conntrack.h>
#endif
static int
extract_icmp6_fields(const struct sk_buff *skb,
unsigned int outside_hdrlen,
int *protocol,
const struct in6_addr **raddr,
const struct in6_addr **laddr,
__be16 *rport,
__be16 *lport,
struct ipv6hdr *ipv6_var)
{
const struct ipv6hdr *inside_iph;
struct icmp6hdr *icmph, _icmph;
__be16 *ports, _ports[2];
u8 inside_nexthdr;
__be16 inside_fragoff;
int inside_hdrlen;
icmph = skb_header_pointer(skb, outside_hdrlen,
sizeof(_icmph), &_icmph);
if (icmph == NULL)
return 1;
if (icmph->icmp6_type & ICMPV6_INFOMSG_MASK)
return 1;
inside_iph = skb_header_pointer(skb, outside_hdrlen + sizeof(_icmph),
sizeof(*ipv6_var), ipv6_var);
if (inside_iph == NULL)
return 1;
inside_nexthdr = inside_iph->nexthdr;
inside_hdrlen = ipv6_skip_exthdr(skb, outside_hdrlen + sizeof(_icmph) +
sizeof(*ipv6_var),
&inside_nexthdr, &inside_fragoff);
if (inside_hdrlen < 0)
return 1; /* hjm: Packet has no/incomplete transport layer headers. */
if (inside_nexthdr != IPPROTO_TCP &&
inside_nexthdr != IPPROTO_UDP)
return 1;
ports = skb_header_pointer(skb, inside_hdrlen,
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_nexthdr;
*laddr = &inside_iph->saddr;
*lport = ports[0];
*raddr = &inside_iph->daddr;
*rport = ports[1];
return 0;
}
static struct sock *
nf_socket_get_sock_v6(struct net *net, struct sk_buff *skb, int doff,
const u8 protocol,
const struct in6_addr *saddr, const struct in6_addr *daddr,
const __be16 sport, const __be16 dport,
const struct net_device *in)
{
switch (protocol) {
case IPPROTO_TCP:
return inet6_lookup(net, &tcp_hashinfo, skb, doff,
saddr, sport, daddr, dport,
in->ifindex);
case IPPROTO_UDP:
return udp6_lib_lookup(net, saddr, sport, daddr, dport,
in->ifindex);
}
return NULL;
}
struct sock *nf_sk_lookup_slow_v6(struct net *net, const struct sk_buff *skb,
const struct net_device *indev)
{
__be16 uninitialized_var(dport), uninitialized_var(sport);
const struct in6_addr *daddr = NULL, *saddr = NULL;
struct ipv6hdr *iph = ipv6_hdr(skb);
struct sk_buff *data_skb = NULL;
int doff = 0;
int thoff = 0, tproto;
tproto = ipv6_find_hdr(skb, &thoff, -1, NULL, NULL);
if (tproto < 0) {
pr_debug("unable to find transport header in IPv6 packet, dropping\n");
return NULL;
}
if (tproto == IPPROTO_UDP || tproto == IPPROTO_TCP) {
struct tcphdr _hdr;
struct udphdr *hp;
hp = skb_header_pointer(skb, thoff, tproto == IPPROTO_UDP ?
sizeof(*hp) : sizeof(_hdr), &_hdr);
if (hp == NULL)
return NULL;
saddr = &iph->saddr;
sport = hp->source;
daddr = &iph->daddr;
dport = hp->dest;
data_skb = (struct sk_buff *)skb;
doff = tproto == IPPROTO_TCP ?
thoff + __tcp_hdrlen((struct tcphdr *)hp) :
thoff + sizeof(*hp);
} else if (tproto == IPPROTO_ICMPV6) {
struct ipv6hdr ipv6_var;
if (extract_icmp6_fields(skb, thoff, &tproto, &saddr, &daddr,
&sport, &dport, &ipv6_var))
return NULL;
} else {
return NULL;
}
return nf_socket_get_sock_v6(net, data_skb, doff, tproto, saddr, daddr,
sport, dport, indev);
}
EXPORT_SYMBOL_GPL(nf_sk_lookup_slow_v6);
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Krisztian Kovacs, Balazs Scheidler");
MODULE_DESCRIPTION("Netfilter IPv6 socket lookup infrastructure");
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