// SPDX-License-Identifier: GPL-2.0-only
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#include <net/netfilter/nf_tproxy.h>
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#include <linux/module.h>
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#include <net/inet6_hashtables.h>
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#include <net/addrconf.h>
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#include <net/udp.h>
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#include <net/tcp.h>
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const struct in6_addr *
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nf_tproxy_laddr6(struct sk_buff *skb, const struct in6_addr *user_laddr,
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const struct in6_addr *daddr)
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{
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struct inet6_dev *indev;
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struct inet6_ifaddr *ifa;
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struct in6_addr *laddr;
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if (!ipv6_addr_any(user_laddr))
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return user_laddr;
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laddr = NULL;
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indev = __in6_dev_get(skb->dev);
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if (indev) {
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read_lock_bh(&indev->lock);
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list_for_each_entry(ifa, &indev->addr_list, if_list) {
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if (ifa->flags & (IFA_F_TENTATIVE | IFA_F_DEPRECATED))
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continue;
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laddr = &ifa->addr;
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break;
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}
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read_unlock_bh(&indev->lock);
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}
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return laddr ? laddr : daddr;
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}
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EXPORT_SYMBOL_GPL(nf_tproxy_laddr6);
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struct sock *
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nf_tproxy_handle_time_wait6(struct sk_buff *skb, int tproto, int thoff,
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struct net *net,
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const struct in6_addr *laddr,
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const __be16 lport,
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struct sock *sk)
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{
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const struct ipv6hdr *iph = ipv6_hdr(skb);
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struct tcphdr _hdr, *hp;
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hp = skb_header_pointer(skb, thoff, sizeof(_hdr), &_hdr);
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if (hp == NULL) {
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inet_twsk_put(inet_twsk(sk));
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return NULL;
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}
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if (hp->syn && !hp->rst && !hp->ack && !hp->fin) {
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/* SYN to a TIME_WAIT socket, we'd rather redirect it
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* to a listener socket if there's one */
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struct sock *sk2;
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sk2 = nf_tproxy_get_sock_v6(net, skb, thoff, tproto,
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&iph->saddr,
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nf_tproxy_laddr6(skb, laddr, &iph->daddr),
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hp->source,
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lport ? lport : hp->dest,
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skb->dev, NF_TPROXY_LOOKUP_LISTENER);
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if (sk2) {
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nf_tproxy_twsk_deschedule_put(inet_twsk(sk));
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sk = sk2;
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}
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}
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return sk;
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}
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EXPORT_SYMBOL_GPL(nf_tproxy_handle_time_wait6);
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struct sock *
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nf_tproxy_get_sock_v6(struct net *net, struct sk_buff *skb, int thoff,
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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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const enum nf_tproxy_lookup_t lookup_type)
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{
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struct sock *sk;
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switch (protocol) {
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case IPPROTO_TCP: {
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struct tcphdr _hdr, *hp;
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hp = skb_header_pointer(skb, thoff,
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sizeof(struct tcphdr), &_hdr);
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if (hp == NULL)
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return NULL;
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switch (lookup_type) {
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case NF_TPROXY_LOOKUP_LISTENER:
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sk = inet6_lookup_listener(net, &tcp_hashinfo, skb,
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thoff + __tcp_hdrlen(hp),
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saddr, sport,
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daddr, ntohs(dport),
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in->ifindex, 0);
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if (sk && !refcount_inc_not_zero(&sk->sk_refcnt))
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sk = NULL;
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/* NOTE: we return listeners even if bound to
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* 0.0.0.0, those are filtered out in
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* xt_socket, since xt_TPROXY needs 0 bound
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* listeners too
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*/
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break;
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case NF_TPROXY_LOOKUP_ESTABLISHED:
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sk = __inet6_lookup_established(net, &tcp_hashinfo,
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saddr, sport, daddr, ntohs(dport),
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in->ifindex, 0);
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break;
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default:
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BUG();
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}
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break;
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}
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case IPPROTO_UDP:
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sk = udp6_lib_lookup(net, saddr, sport, daddr, dport,
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in->ifindex);
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if (sk) {
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int connected = (sk->sk_state == TCP_ESTABLISHED);
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int wildcard = ipv6_addr_any(&sk->sk_v6_rcv_saddr);
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/* NOTE: we return listeners even if bound to
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* 0.0.0.0, those are filtered out in
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* xt_socket, since xt_TPROXY needs 0 bound
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* listeners too
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*/
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if ((lookup_type == NF_TPROXY_LOOKUP_ESTABLISHED && (!connected || wildcard)) ||
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(lookup_type == NF_TPROXY_LOOKUP_LISTENER && connected)) {
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sock_put(sk);
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sk = NULL;
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}
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}
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break;
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default:
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WARN_ON(1);
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sk = NULL;
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}
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pr_debug("tproxy socket lookup: proto %u %pI6:%u -> %pI6:%u, lookup type: %d, sock %p\n",
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protocol, saddr, ntohs(sport), daddr, ntohs(dport), lookup_type, sk);
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return sk;
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}
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EXPORT_SYMBOL_GPL(nf_tproxy_get_sock_v6);
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MODULE_LICENSE("GPL");
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MODULE_AUTHOR("Balazs Scheidler, Krisztian Kovacs");
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MODULE_DESCRIPTION("Netfilter IPv6 transparent proxy support");
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