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