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Commit b8dd6a22 authored by Hannes Frederic Sowa's avatar Hannes Frederic Sowa Committed by Pablo Neira Ayuso
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netfilter: implement RFC3168 5.3 (ecn protection) for ipv6 fragmentation handling 



This change brings netfilter reassembly logic on par with
reassembly.c. The corresponding change in net-next is
(eec2e618 ipv6: implement RFC3168 5.3 (ecn protection) for
ipv6 fragmentation handling)

Cc: Eric Dumazet <eric.dumazet@gmail.com>
Cc: Jesper Dangaard Brouer <jbrouer@redhat.com>
Cc: YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org>
Signed-off-by: default avatarHannes Frederic Sowa <hannes@stressinduktion.org>
Signed-off-by: default avatarPablo Neira Ayuso <pablo@netfilter.org>
parent 12202fa7

net/ipv6/netfilter/nf_conntrack_reasm.c

+20 −2
Original line number Diff line number Diff line
@@ -41,6 +41,7 @@ 
#include <net/rawv6.h>

#include <net/ndisc.h>

#include <net/addrconf.h>

#include <net/inet_ecn.h>

#include <net/netfilter/ipv6/nf_conntrack_ipv6.h>

#include <linux/sysctl.h>

#include <linux/netfilter.h>
@@ -138,6 +139,11 @@ static void __net_exit nf_ct_frags6_sysctl_unregister(struct net *net) 
}

#endif



static inline u8 ip6_frag_ecn(const struct ipv6hdr *ipv6h)

{

	return 1 << (ipv6_get_dsfield(ipv6h) & INET_ECN_MASK);

}



static unsigned int nf_hashfn(struct inet_frag_queue *q)

{

	const struct frag_queue *nq;
@@ -166,7 +172,7 @@ static void nf_ct_frag6_expire(unsigned long data) 
/* Creation primitives. */

static inline struct frag_queue *fq_find(struct net *net, __be32 id,

					 u32 user, struct in6_addr *src,

					 struct in6_addr *dst)

					 struct in6_addr *dst, u8 ecn)

{

	struct inet_frag_queue *q;

	struct ip6_create_arg arg;
@@ -176,6 +182,7 @@ static inline struct frag_queue *fq_find(struct net *net, __be32 id, 
	arg.user = user;

	arg.src = src;

	arg.dst = dst;

	arg.ecn = ecn;



	read_lock_bh(&nf_frags.lock);

	hash = inet6_hash_frag(id, src, dst, nf_frags.rnd);
@@ -196,6 +203,7 @@ static int nf_ct_frag6_queue(struct frag_queue *fq, struct sk_buff *skb, 
	struct sk_buff *prev, *next;

	unsigned int payload_len;

	int offset, end;

	u8 ecn;



	if (fq->q.last_in & INET_FRAG_COMPLETE) {

		pr_debug("Already completed\n");
@@ -213,6 +221,8 @@ static int nf_ct_frag6_queue(struct frag_queue *fq, struct sk_buff *skb, 
		return -1;

	}



	ecn = ip6_frag_ecn(ipv6_hdr(skb));



	if (skb->ip_summed == CHECKSUM_COMPLETE) {

		const unsigned char *nh = skb_network_header(skb);

		skb->csum = csum_sub(skb->csum,
@@ -317,6 +327,7 @@ static int nf_ct_frag6_queue(struct frag_queue *fq, struct sk_buff *skb, 
	}

	fq->q.stamp = skb->tstamp;

	fq->q.meat += skb->len;

	fq->ecn |= ecn;

	if (payload_len > fq->q.max_size)

		fq->q.max_size = payload_len;

	add_frag_mem_limit(&fq->q, skb->truesize);
@@ -352,12 +363,17 @@ nf_ct_frag6_reasm(struct frag_queue *fq, struct net_device *dev) 
{

	struct sk_buff *fp, *op, *head = fq->q.fragments;

	int    payload_len;

	u8 ecn;



	inet_frag_kill(&fq->q, &nf_frags);



	WARN_ON(head == NULL);

	WARN_ON(NFCT_FRAG6_CB(head)->offset != 0);



	ecn = ip_frag_ecn_table[fq->ecn];

	if (unlikely(ecn == 0xff))

		goto out_fail;



	/* Unfragmented part is taken from the first segment. */

	payload_len = ((head->data - skb_network_header(head)) -

		       sizeof(struct ipv6hdr) + fq->q.len -
@@ -428,6 +444,7 @@ nf_ct_frag6_reasm(struct frag_queue *fq, struct net_device *dev) 
	head->dev = dev;

	head->tstamp = fq->q.stamp;

	ipv6_hdr(head)->payload_len = htons(payload_len);

	ipv6_change_dsfield(ipv6_hdr(head), 0xff, ecn);

	IP6CB(head)->frag_max_size = sizeof(struct ipv6hdr) + fq->q.max_size;



	/* Yes, and fold redundant checksum back. 8) */
@@ -572,7 +589,8 @@ struct sk_buff *nf_ct_frag6_gather(struct sk_buff *skb, u32 user) 
	inet_frag_evictor(&net->nf_frag.frags, &nf_frags, false);

	local_bh_enable();



	fq = fq_find(net, fhdr->identification, user, &hdr->saddr, &hdr->daddr);

	fq = fq_find(net, fhdr->identification, user, &hdr->saddr, &hdr->daddr,

		     ip6_frag_ecn(hdr));

	if (fq == NULL) {

		pr_debug("Can't find and can't create new queue\n");

		goto ret_orig;