net/ipv6/netfilter.c - linux - Git at Google

 /*
  * IPv6 specific functions of netfilter core
  *
  * Rusty Russell (C) 2000 -- This code is GPL.
  * Patrick McHardy (C) 2006-2012
  */
 #include <linux/kernel.h>
 #include <linux/init.h>
 #include <linux/ipv6.h>
 #include <linux/netfilter.h>
 #include <linux/netfilter_ipv6.h>
 #include <linux/export.h>
 #include <net/addrconf.h>
 #include <net/dst.h>
 #include <net/ipv6.h>
 #include <net/ip6_route.h>
 #include <net/xfrm.h>
 #include <net/netfilter/nf_queue.h>
 #include <net/netfilter/nf_conntrack_bridge.h>
 #include <net/netfilter/ipv6/nf_defrag_ipv6.h>
 #include "../bridge/br_private.h"

 int ip6_route_me_harder(struct net *net, struct sock *sk_partial, struct sk_buff *skb)
 {
 	const struct ipv6hdr *iph = ipv6_hdr(skb);
 	struct sock *sk = sk_to_full_sk(sk_partial);
 	struct flow_keys flkeys;
 	unsigned int hh_len;
 	struct dst_entry *dst;
 	int strict = (ipv6_addr_type(&iph->daddr) &
 		      (IPV6_ADDR_MULTICAST | IPV6_ADDR_LINKLOCAL));
 	struct flowi6 fl6 = {
 		.flowi6_oif = sk && sk->sk_bound_dev_if ? sk->sk_bound_dev_if :
 			strict ? skb_dst(skb)->dev->ifindex : 0,
 		.flowi6_mark = skb->mark,
 		.flowi6_uid = sock_net_uid(net, sk),
 		.daddr = iph->daddr,
 		.saddr = iph->saddr,
 	};
 	int err;

 	fib6_rules_early_flow_dissect(net, skb, &fl6, &flkeys);
 	dst = ip6_route_output(net, sk, &fl6);
 	err = dst->error;
 	if (err) {
 		IP6_INC_STATS(net, ip6_dst_idev(dst), IPSTATS_MIB_OUTNOROUTES);
 		net_dbg_ratelimited("ip6_route_me_harder: No more route\n");
 		dst_release(dst);
 		return err;
 	}

 	/* Drop old route. */
 	skb_dst_drop(skb);

 	skb_dst_set(skb, dst);

 #ifdef CONFIG_XFRM
 	if (!(IP6CB(skb)->flags & IP6SKB_XFRM_TRANSFORMED) &&
 	    xfrm_decode_session(skb, flowi6_to_flowi(&fl6), AF_INET6) == 0) {
 		skb_dst_set(skb, NULL);
 		dst = xfrm_lookup(net, dst, flowi6_to_flowi(&fl6), sk, 0);
 		if (IS_ERR(dst))
 			return PTR_ERR(dst);
 		skb_dst_set(skb, dst);
 	}
 #endif

 	/* Change in oif may mean change in hh_len. */
 	hh_len = skb_dst(skb)->dev->hard_header_len;
 	if (skb_headroom(skb) < hh_len &&
 	    pskb_expand_head(skb, HH_DATA_ALIGN(hh_len - skb_headroom(skb)),
 			     0, GFP_ATOMIC))
 		return -ENOMEM;

 	return 0;
 }
 EXPORT_SYMBOL(ip6_route_me_harder);

 static int nf_ip6_reroute(struct sk_buff *skb,
 			  const struct nf_queue_entry *entry)
 {
 	struct ip6_rt_info *rt_info = nf_queue_entry_reroute(entry);

 	if (entry->state.hook == NF_INET_LOCAL_OUT) {
 		const struct ipv6hdr *iph = ipv6_hdr(skb);
 		if (!ipv6_addr_equal(&iph->daddr, &rt_info->daddr) ||
 		    !ipv6_addr_equal(&iph->saddr, &rt_info->saddr) ||
 		    skb->mark != rt_info->mark)
 			return ip6_route_me_harder(entry->state.net, entry->state.sk, skb);
 	}
 	return 0;
 }

 int __nf_ip6_route(struct net *net, struct dst_entry **dst,
 		   struct flowi *fl, bool strict)
 {
 	static const struct ipv6_pinfo fake_pinfo;
 	static const struct inet_sock fake_sk = {
 		/* makes ip6_route_output set RT6_LOOKUP_F_IFACE: */
 		.sk.sk_bound_dev_if = 1,
 		.pinet6 = (struct ipv6_pinfo *) &fake_pinfo,
 	};
 	const void *sk = strict ? &fake_sk : NULL;
 	struct dst_entry *result;
 	int err;

 	result = ip6_route_output(net, sk, &fl->u.ip6);
 	err = result->error;
 	if (err)
 		dst_release(result);
 	else
 		*dst = result;
 	return err;
 }
 EXPORT_SYMBOL_GPL(__nf_ip6_route);

 int br_ip6_fragment(struct net *net, struct sock *sk, struct sk_buff *skb,
 		    struct nf_bridge_frag_data *data,
 		    int (*output)(struct net *, struct sock *sk,
 				  const struct nf_bridge_frag_data *data,
 				  struct sk_buff *))
 {
 	int frag_max_size = BR_INPUT_SKB_CB(skb)->frag_max_size;
 	bool mono_delivery_time = skb->mono_delivery_time;
 	ktime_t tstamp = skb->tstamp;
 	struct ip6_frag_state state;
 	u8 *prevhdr, nexthdr = 0;
 	unsigned int mtu, hlen;
 	int hroom, err = 0;
 	__be32 frag_id;

 	err = ip6_find_1stfragopt(skb, &prevhdr);
 	if (err < 0)
 		goto blackhole;
 	hlen = err;
 	nexthdr = *prevhdr;

 	mtu = skb->dev->mtu;
 	if (frag_max_size > mtu ||
 	    frag_max_size < IPV6_MIN_MTU)
 		goto blackhole;

 	mtu = frag_max_size;
 	if (mtu < hlen + sizeof(struct frag_hdr) + 8)
 		goto blackhole;
 	mtu -= hlen + sizeof(struct frag_hdr);

 	frag_id = ipv6_select_ident(net, &ipv6_hdr(skb)->daddr,
 				    &ipv6_hdr(skb)->saddr);

 	if (skb->ip_summed == CHECKSUM_PARTIAL &&
 	    (err = skb_checksum_help(skb)))
 		goto blackhole;

 	hroom = LL_RESERVED_SPACE(skb->dev);
 	if (skb_has_frag_list(skb)) {
 		unsigned int first_len = skb_pagelen(skb);
 		struct ip6_fraglist_iter iter;
 		struct sk_buff *frag2;

 		if (first_len - hlen > mtu ||
 		    skb_headroom(skb) < (hroom + sizeof(struct frag_hdr)))
 			goto blackhole;

 		if (skb_cloned(skb))
 			goto slow_path;

 		skb_walk_frags(skb, frag2) {
 			if (frag2->len > mtu ||
 			    skb_headroom(frag2) < (hlen + hroom + sizeof(struct frag_hdr)))
 				goto blackhole;

 			/* Partially cloned skb? */
 			if (skb_shared(frag2))
 				goto slow_path;
 		}

 		err = ip6_fraglist_init(skb, hlen, prevhdr, nexthdr, frag_id,
 					&iter);
 		if (err < 0)
 			goto blackhole;

 		for (;;) {
 			/* Prepare header of the next frame,
 			 * before previous one went down.
 			 */
 			if (iter.frag)
 				ip6_fraglist_prepare(skb, &iter);

 			skb_set_delivery_time(skb, tstamp, mono_delivery_time);
 			err = output(net, sk, data, skb);
 			if (err || !iter.frag)
 				break;

 			skb = ip6_fraglist_next(&iter);
 		}

 		kfree(iter.tmp_hdr);
 		if (!err)
 			return 0;

 		kfree_skb_list(iter.frag);
 		return err;
 	}
 slow_path:
 	/* This is a linearized skbuff, the original geometry is lost for us.
 	 * This may also be a clone skbuff, we could preserve the geometry for
 	 * the copies but probably not worth the effort.
 	 */
 	ip6_frag_init(skb, hlen, mtu, skb->dev->needed_tailroom,
 		      LL_RESERVED_SPACE(skb->dev), prevhdr, nexthdr, frag_id,
 		      &state);

 	while (state.left > 0) {
 		struct sk_buff *skb2;

 		skb2 = ip6_frag_next(skb, &state);
 		if (IS_ERR(skb2)) {
 			err = PTR_ERR(skb2);
 			goto blackhole;
 		}

 		skb_set_delivery_time(skb2, tstamp, mono_delivery_time);
 		err = output(net, sk, data, skb2);
 		if (err)
 			goto blackhole;
 	}
 	consume_skb(skb);
 	return err;

 blackhole:
 	kfree_skb(skb);
 	return 0;
 }
 EXPORT_SYMBOL_GPL(br_ip6_fragment);

 static const struct nf_ipv6_ops ipv6ops = {
 #if IS_MODULE(CONFIG_IPV6)
 	.chk_addr		= ipv6_chk_addr,
 	.route_me_harder	= ip6_route_me_harder,
 	.dev_get_saddr		= ipv6_dev_get_saddr,
 	.route			= __nf_ip6_route,
 #if IS_ENABLED(CONFIG_SYN_COOKIES)
 	.cookie_init_sequence	= __cookie_v6_init_sequence,
 	.cookie_v6_check	= __cookie_v6_check,
 #endif
 #endif
 	.route_input		= ip6_route_input,
 	.fragment		= ip6_fragment,
 	.reroute		= nf_ip6_reroute,
 #if IS_MODULE(CONFIG_IPV6)
 	.br_fragment		= br_ip6_fragment,
 #endif
 };

 int __init ipv6_netfilter_init(void)
 {
 	RCU_INIT_POINTER(nf_ipv6_ops, &ipv6ops);
 	return 0;
 }

 /* This can be called from inet6_init() on errors, so it cannot
  * be marked __exit. -DaveM
  */
 void ipv6_netfilter_fini(void)
 {
 	RCU_INIT_POINTER(nf_ipv6_ops, NULL);
 }
	/*
	* IPv6 specific functions of netfilter core
	*
	* Rusty Russell (C) 2000 -- This code is GPL.
	* Patrick McHardy (C) 2006-2012
	*/
	#include <linux/kernel.h>
	#include <linux/init.h>
	#include <linux/ipv6.h>
	#include <linux/netfilter.h>
	#include <linux/netfilter_ipv6.h>
	#include <linux/export.h>
	#include <net/addrconf.h>
	#include <net/dst.h>
	#include <net/ipv6.h>
	#include <net/ip6_route.h>
	#include <net/xfrm.h>
	#include <net/netfilter/nf_queue.h>
	#include <net/netfilter/nf_conntrack_bridge.h>
	#include <net/netfilter/ipv6/nf_defrag_ipv6.h>
	#include "../bridge/br_private.h"

	int ip6_route_me_harder(struct net net, struct sock sk_partial, struct sk_buff *skb)
	{
	const struct ipv6hdr *iph = ipv6_hdr(skb);
	struct sock *sk = sk_to_full_sk(sk_partial);
	struct flow_keys flkeys;
	unsigned int hh_len;
	struct dst_entry *dst;
	int strict = (ipv6_addr_type(&iph->daddr) &
	(IPV6_ADDR_MULTICAST \| IPV6_ADDR_LINKLOCAL));
	struct flowi6 fl6 = {
	.flowi6_oif = sk && sk->sk_bound_dev_if ? sk->sk_bound_dev_if :
	strict ? skb_dst(skb)->dev->ifindex : 0,
	.flowi6_mark = skb->mark,
	.flowi6_uid = sock_net_uid(net, sk),
	.daddr = iph->daddr,
	.saddr = iph->saddr,
	};
	int err;

	fib6_rules_early_flow_dissect(net, skb, &fl6, &flkeys);
	dst = ip6_route_output(net, sk, &fl6);
	err = dst->error;
	if (err) {
	IP6_INC_STATS(net, ip6_dst_idev(dst), IPSTATS_MIB_OUTNOROUTES);
	net_dbg_ratelimited("ip6_route_me_harder: No more route\n");
	dst_release(dst);
	return err;
	}

	/* Drop old route. */
	skb_dst_drop(skb);

	skb_dst_set(skb, dst);

	#ifdef CONFIG_XFRM
	if (!(IP6CB(skb)->flags & IP6SKB_XFRM_TRANSFORMED) &&
	xfrm_decode_session(skb, flowi6_to_flowi(&fl6), AF_INET6) == 0) {
	skb_dst_set(skb, NULL);
	dst = xfrm_lookup(net, dst, flowi6_to_flowi(&fl6), sk, 0);
	if (IS_ERR(dst))
	return PTR_ERR(dst);
	skb_dst_set(skb, dst);
	}
	#endif

	/* Change in oif may mean change in hh_len. */
	hh_len = skb_dst(skb)->dev->hard_header_len;
	if (skb_headroom(skb) < hh_len &&
	pskb_expand_head(skb, HH_DATA_ALIGN(hh_len - skb_headroom(skb)),
	0, GFP_ATOMIC))
	return -ENOMEM;

	return 0;
	}
	EXPORT_SYMBOL(ip6_route_me_harder);

	static int nf_ip6_reroute(struct sk_buff *skb,
	const struct nf_queue_entry *entry)
	{
	struct ip6_rt_info *rt_info = nf_queue_entry_reroute(entry);

	if (entry->state.hook == NF_INET_LOCAL_OUT) {
	const struct ipv6hdr *iph = ipv6_hdr(skb);
	if (!ipv6_addr_equal(&iph->daddr, &rt_info->daddr) \|\|
	!ipv6_addr_equal(&iph->saddr, &rt_info->saddr) \|\|
	skb->mark != rt_info->mark)
	return ip6_route_me_harder(entry->state.net, entry->state.sk, skb);
	}
	return 0;
	}

	int __nf_ip6_route(struct net net, struct dst_entry *dst,
	struct flowi *fl, bool strict)
	{
	static const struct ipv6_pinfo fake_pinfo;
	static const struct inet_sock fake_sk = {
	/* makes ip6_route_output set RT6_LOOKUP_F_IFACE: */
	.sk.sk_bound_dev_if = 1,
	.pinet6 = (struct ipv6_pinfo *) &fake_pinfo,
	};
	const void *sk = strict ? &fake_sk : NULL;
	struct dst_entry *result;
	int err;

	result = ip6_route_output(net, sk, &fl->u.ip6);
	err = result->error;
	if (err)
	dst_release(result);
	else
	*dst = result;
	return err;
	}
	EXPORT_SYMBOL_GPL(__nf_ip6_route);

	int br_ip6_fragment(struct net net, struct sock sk, struct sk_buff *skb,
	struct nf_bridge_frag_data *data,
	int (output)(struct net , struct sock *sk,
	const struct nf_bridge_frag_data *data,
	struct sk_buff *))
	{
	int frag_max_size = BR_INPUT_SKB_CB(skb)->frag_max_size;
	bool mono_delivery_time = skb->mono_delivery_time;
	ktime_t tstamp = skb->tstamp;
	struct ip6_frag_state state;
	u8 *prevhdr, nexthdr = 0;
	unsigned int mtu, hlen;
	int hroom, err = 0;
	__be32 frag_id;

	err = ip6_find_1stfragopt(skb, &prevhdr);
	if (err < 0)
	goto blackhole;
	hlen = err;
	nexthdr = *prevhdr;

	mtu = skb->dev->mtu;
	if (frag_max_size > mtu \|\|
	frag_max_size < IPV6_MIN_MTU)
	goto blackhole;

	mtu = frag_max_size;
	if (mtu < hlen + sizeof(struct frag_hdr) + 8)
	goto blackhole;
	mtu -= hlen + sizeof(struct frag_hdr);

	frag_id = ipv6_select_ident(net, &ipv6_hdr(skb)->daddr,
	&ipv6_hdr(skb)->saddr);

	if (skb->ip_summed == CHECKSUM_PARTIAL &&
	(err = skb_checksum_help(skb)))
	goto blackhole;

	hroom = LL_RESERVED_SPACE(skb->dev);
	if (skb_has_frag_list(skb)) {
	unsigned int first_len = skb_pagelen(skb);
	struct ip6_fraglist_iter iter;
	struct sk_buff *frag2;

	if (first_len - hlen > mtu \|\|
	skb_headroom(skb) < (hroom + sizeof(struct frag_hdr)))
	goto blackhole;

	if (skb_cloned(skb))
	goto slow_path;

	skb_walk_frags(skb, frag2) {
	if (frag2->len > mtu \|\|
	skb_headroom(frag2) < (hlen + hroom + sizeof(struct frag_hdr)))
	goto blackhole;

	/* Partially cloned skb? */
	if (skb_shared(frag2))
	goto slow_path;
	}

	err = ip6_fraglist_init(skb, hlen, prevhdr, nexthdr, frag_id,
	&iter);
	if (err < 0)
	goto blackhole;

	for (;;) {
	/* Prepare header of the next frame,
	* before previous one went down.
	*/
	if (iter.frag)
	ip6_fraglist_prepare(skb, &iter);

	skb_set_delivery_time(skb, tstamp, mono_delivery_time);
	err = output(net, sk, data, skb);
	if (err \|\| !iter.frag)
	break;

	skb = ip6_fraglist_next(&iter);
	}

	kfree(iter.tmp_hdr);
	if (!err)
	return 0;

	kfree_skb_list(iter.frag);
	return err;
	}
	slow_path:
	/* This is a linearized skbuff, the original geometry is lost for us.
	* This may also be a clone skbuff, we could preserve the geometry for
	* the copies but probably not worth the effort.
	*/
	ip6_frag_init(skb, hlen, mtu, skb->dev->needed_tailroom,
	LL_RESERVED_SPACE(skb->dev), prevhdr, nexthdr, frag_id,
	&state);

	while (state.left > 0) {
	struct sk_buff *skb2;

	skb2 = ip6_frag_next(skb, &state);
	if (IS_ERR(skb2)) {
	err = PTR_ERR(skb2);
	goto blackhole;
	}

	skb_set_delivery_time(skb2, tstamp, mono_delivery_time);
	err = output(net, sk, data, skb2);
	if (err)
	goto blackhole;
	}
	consume_skb(skb);
	return err;

	blackhole:
	kfree_skb(skb);
	return 0;
	}
	EXPORT_SYMBOL_GPL(br_ip6_fragment);

	static const struct nf_ipv6_ops ipv6ops = {
	#if IS_MODULE(CONFIG_IPV6)
	.chk_addr = ipv6_chk_addr,
	.route_me_harder = ip6_route_me_harder,
	.dev_get_saddr = ipv6_dev_get_saddr,
	.route = __nf_ip6_route,
	#if IS_ENABLED(CONFIG_SYN_COOKIES)
	.cookie_init_sequence = __cookie_v6_init_sequence,
	.cookie_v6_check = __cookie_v6_check,
	#endif
	#endif
	.route_input = ip6_route_input,
	.fragment = ip6_fragment,
	.reroute = nf_ip6_reroute,
	#if IS_MODULE(CONFIG_IPV6)
	.br_fragment = br_ip6_fragment,
	#endif
	};

	int __init ipv6_netfilter_init(void)
	{
	RCU_INIT_POINTER(nf_ipv6_ops, &ipv6ops);
	return 0;
	}

	/* This can be called from inet6_init() on errors, so it cannot
	* be marked __exit. -DaveM
	*/
	void ipv6_netfilter_fini(void)
	{
	RCU_INIT_POINTER(nf_ipv6_ops, NULL);
	}