266 lines
6.5 KiB
C
266 lines
6.5 KiB
C
/*
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* IPv6 specific functions of netfilter core
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*
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* Rusty Russell (C) 2000 -- This code is GPL.
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* Patrick McHardy (C) 2006-2012
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*/
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#include <linux/kernel.h>
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#include <linux/init.h>
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#include <linux/ipv6.h>
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#include <linux/netfilter.h>
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#include <linux/netfilter_ipv6.h>
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#include <linux/export.h>
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#include <net/addrconf.h>
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#include <net/dst.h>
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#include <net/ipv6.h>
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#include <net/ip6_route.h>
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#include <net/xfrm.h>
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#include <net/netfilter/nf_queue.h>
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#include <net/netfilter/nf_conntrack_bridge.h>
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#include <net/netfilter/ipv6/nf_defrag_ipv6.h>
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#include "../bridge/br_private.h"
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int ip6_route_me_harder(struct net *net, struct sk_buff *skb)
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{
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const struct ipv6hdr *iph = ipv6_hdr(skb);
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struct sock *sk = sk_to_full_sk(skb->sk);
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unsigned int hh_len;
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struct dst_entry *dst;
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int strict = (ipv6_addr_type(&iph->daddr) &
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(IPV6_ADDR_MULTICAST | IPV6_ADDR_LINKLOCAL));
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struct flowi6 fl6 = {
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.flowi6_oif = sk && sk->sk_bound_dev_if ? sk->sk_bound_dev_if :
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strict ? skb_dst(skb)->dev->ifindex : 0,
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.flowi6_mark = skb->mark,
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.flowi6_uid = sock_net_uid(net, sk),
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.daddr = iph->daddr,
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.saddr = iph->saddr,
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};
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int err;
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dst = ip6_route_output(net, sk, &fl6);
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err = dst->error;
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if (err) {
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IP6_INC_STATS(net, ip6_dst_idev(dst), IPSTATS_MIB_OUTNOROUTES);
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net_dbg_ratelimited("ip6_route_me_harder: No more route\n");
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dst_release(dst);
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return err;
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}
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/* Drop old route. */
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skb_dst_drop(skb);
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skb_dst_set(skb, dst);
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#ifdef CONFIG_XFRM
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if (!(IP6CB(skb)->flags & IP6SKB_XFRM_TRANSFORMED) &&
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xfrm_decode_session(skb, flowi6_to_flowi(&fl6), AF_INET6) == 0) {
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skb_dst_set(skb, NULL);
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dst = xfrm_lookup(net, dst, flowi6_to_flowi(&fl6), sk, 0);
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if (IS_ERR(dst))
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return PTR_ERR(dst);
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skb_dst_set(skb, dst);
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}
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#endif
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/* Change in oif may mean change in hh_len. */
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hh_len = skb_dst(skb)->dev->hard_header_len;
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if (skb_headroom(skb) < hh_len &&
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pskb_expand_head(skb, HH_DATA_ALIGN(hh_len - skb_headroom(skb)),
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0, GFP_ATOMIC))
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return -ENOMEM;
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return 0;
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}
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EXPORT_SYMBOL(ip6_route_me_harder);
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static int nf_ip6_reroute(struct sk_buff *skb,
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const struct nf_queue_entry *entry)
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{
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struct ip6_rt_info *rt_info = nf_queue_entry_reroute(entry);
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if (entry->state.hook == NF_INET_LOCAL_OUT) {
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const struct ipv6hdr *iph = ipv6_hdr(skb);
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if (!ipv6_addr_equal(&iph->daddr, &rt_info->daddr) ||
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!ipv6_addr_equal(&iph->saddr, &rt_info->saddr) ||
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skb->mark != rt_info->mark)
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return ip6_route_me_harder(entry->state.net, skb);
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}
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return 0;
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}
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int __nf_ip6_route(struct net *net, struct dst_entry **dst,
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struct flowi *fl, bool strict)
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{
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static const struct ipv6_pinfo fake_pinfo;
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static const struct inet_sock fake_sk = {
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/* makes ip6_route_output set RT6_LOOKUP_F_IFACE: */
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.sk.sk_bound_dev_if = 1,
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.pinet6 = (struct ipv6_pinfo *) &fake_pinfo,
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};
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const void *sk = strict ? &fake_sk : NULL;
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struct dst_entry *result;
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int err;
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result = ip6_route_output(net, sk, &fl->u.ip6);
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err = result->error;
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if (err)
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dst_release(result);
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else
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*dst = result;
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return err;
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}
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EXPORT_SYMBOL_GPL(__nf_ip6_route);
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int br_ip6_fragment(struct net *net, struct sock *sk, struct sk_buff *skb,
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struct nf_ct_bridge_frag_data *data,
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int (*output)(struct net *, struct sock *sk,
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const struct nf_ct_bridge_frag_data *data,
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struct sk_buff *))
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{
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int frag_max_size = BR_INPUT_SKB_CB(skb)->frag_max_size;
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struct ip6_frag_state state;
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u8 *prevhdr, nexthdr = 0;
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unsigned int mtu, hlen;
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int hroom, err = 0;
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__be32 frag_id;
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err = ip6_find_1stfragopt(skb, &prevhdr);
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if (err < 0)
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goto blackhole;
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hlen = err;
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nexthdr = *prevhdr;
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mtu = skb->dev->mtu;
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if (frag_max_size > mtu ||
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frag_max_size < IPV6_MIN_MTU)
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goto blackhole;
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mtu = frag_max_size;
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if (mtu < hlen + sizeof(struct frag_hdr) + 8)
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goto blackhole;
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mtu -= hlen + sizeof(struct frag_hdr);
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frag_id = ipv6_select_ident(net, &ipv6_hdr(skb)->daddr,
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&ipv6_hdr(skb)->saddr);
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if (skb->ip_summed == CHECKSUM_PARTIAL &&
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(err = skb_checksum_help(skb)))
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goto blackhole;
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hroom = LL_RESERVED_SPACE(skb->dev);
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if (skb_has_frag_list(skb)) {
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unsigned int first_len = skb_pagelen(skb);
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struct ip6_fraglist_iter iter;
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struct sk_buff *frag2;
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if (first_len - hlen > mtu ||
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skb_headroom(skb) < (hroom + sizeof(struct frag_hdr)))
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goto blackhole;
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if (skb_cloned(skb))
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goto slow_path;
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skb_walk_frags(skb, frag2) {
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if (frag2->len > mtu ||
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skb_headroom(frag2) < (hlen + hroom + sizeof(struct frag_hdr)))
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goto blackhole;
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/* Partially cloned skb? */
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if (skb_shared(frag2))
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goto slow_path;
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}
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err = ip6_fraglist_init(skb, hlen, prevhdr, nexthdr, frag_id,
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&iter);
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if (err < 0)
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goto blackhole;
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for (;;) {
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/* Prepare header of the next frame,
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* before previous one went down.
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*/
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if (iter.frag)
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ip6_fraglist_prepare(skb, &iter);
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err = output(net, sk, data, skb);
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if (err || !iter.frag)
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break;
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skb = ip6_fraglist_next(&iter);
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}
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kfree(iter.tmp_hdr);
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if (!err)
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return 0;
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kfree_skb_list(iter.frag);
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return err;
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}
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slow_path:
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/* This is a linearized skbuff, the original geometry is lost for us.
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* This may also be a clone skbuff, we could preserve the geometry for
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* the copies but probably not worth the effort.
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*/
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ip6_frag_init(skb, hlen, mtu, skb->dev->needed_tailroom,
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LL_RESERVED_SPACE(skb->dev), prevhdr, nexthdr, frag_id,
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&state);
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while (state.left > 0) {
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struct sk_buff *skb2;
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skb2 = ip6_frag_next(skb, &state);
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if (IS_ERR(skb2)) {
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err = PTR_ERR(skb2);
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goto blackhole;
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}
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err = output(net, sk, data, skb2);
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if (err)
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goto blackhole;
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}
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consume_skb(skb);
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return err;
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blackhole:
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kfree_skb(skb);
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return 0;
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}
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EXPORT_SYMBOL_GPL(br_ip6_fragment);
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static const struct nf_ipv6_ops ipv6ops = {
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#if IS_MODULE(CONFIG_IPV6)
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.chk_addr = ipv6_chk_addr,
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.route_me_harder = ip6_route_me_harder,
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.dev_get_saddr = ipv6_dev_get_saddr,
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.route = __nf_ip6_route,
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#if IS_ENABLED(CONFIG_SYN_COOKIES)
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.cookie_init_sequence = __cookie_v6_init_sequence,
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.cookie_v6_check = __cookie_v6_check,
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#endif
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#endif
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.route_input = ip6_route_input,
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.fragment = ip6_fragment,
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.reroute = nf_ip6_reroute,
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#if IS_MODULE(CONFIG_IPV6) && IS_ENABLED(CONFIG_NF_DEFRAG_IPV6)
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.br_defrag = nf_ct_frag6_gather,
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#endif
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#if IS_MODULE(CONFIG_IPV6)
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.br_fragment = br_ip6_fragment,
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#endif
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};
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int __init ipv6_netfilter_init(void)
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{
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RCU_INIT_POINTER(nf_ipv6_ops, &ipv6ops);
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return 0;
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}
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/* This can be called from inet6_init() on errors, so it cannot
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* be marked __exit. -DaveM
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*/
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void ipv6_netfilter_fini(void)
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{
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RCU_INIT_POINTER(nf_ipv6_ops, NULL);
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}
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