Commit eec2e618 authored by Hannes Frederic Sowa's avatar Hannes Frederic Sowa Committed by David S. Miller
Browse files

ipv6: implement RFC3168 5.3 (ecn protection) for ipv6 fragmentation handling 



Hello!

After patch 1 got accepted to net-next I will also send a patch to
netfilter-devel to make the corresponding changes to the netfilter
reassembly logic.

Thanks,

  Hannes

-- >8 --
[PATCH 2/2] ipv6: implement RFC3168 5.3 (ecn protection) for ipv6 fragmentation handling

This patch also ensures that INET_ECN_CE is propagated if one fragment
had the codepoint set.

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>
Acked-by: default avatarYOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent be991971

include/net/ipv6.h

+2 −0
Original line number Diff line number Diff line
@@ -478,6 +478,7 @@ struct ip6_create_arg { 
	u32 user;

	const struct in6_addr *src;

	const struct in6_addr *dst;

	u8 ecn;

};



void ip6_frag_init(struct inet_frag_queue *q, void *a);
@@ -497,6 +498,7 @@ struct frag_queue { 
	int			iif;

	unsigned int		csum;

	__u16			nhoffset;

	u8			ecn;

};



void ip6_expire_frag_queue(struct net *net, struct frag_queue *fq,

net/ipv6/reassembly.c

+21 −2
Original line number Diff line number Diff line
@@ -58,6 +58,7 @@ 
#include <net/ndisc.h>

#include <net/addrconf.h>

#include <net/inet_frag.h>

#include <net/inet_ecn.h>



struct ip6frag_skb_cb

{
@@ -67,6 +68,10 @@ struct ip6frag_skb_cb 


#define FRAG6_CB(skb)	((struct ip6frag_skb_cb*)((skb)->cb))



static inline u8 ip6_frag_ecn(const struct ipv6hdr *ipv6h)

{

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

}



static struct inet_frags ip6_frags;
@@ -119,6 +124,7 @@ void ip6_frag_init(struct inet_frag_queue *q, void *a) 
	fq->user = arg->user;

	fq->saddr = *arg->src;

	fq->daddr = *arg->dst;

	fq->ecn = arg->ecn;

}

EXPORT_SYMBOL(ip6_frag_init);
@@ -173,7 +179,8 @@ static void ip6_frag_expire(unsigned long data) 
}



static __inline__ struct frag_queue *

fq_find(struct net *net, __be32 id, const struct in6_addr *src, const struct in6_addr *dst)

fq_find(struct net *net, __be32 id, const struct in6_addr *src,

	const struct in6_addr *dst, u8 ecn)

{

	struct inet_frag_queue *q;

	struct ip6_create_arg arg;
@@ -183,6 +190,7 @@ fq_find(struct net *net, __be32 id, const struct in6_addr *src, const struct in6 
	arg.user = IP6_DEFRAG_LOCAL_DELIVER;

	arg.src = src;

	arg.dst = dst;

	arg.ecn = ecn;



	read_lock(&ip6_frags.lock);

	hash = inet6_hash_frag(id, src, dst, ip6_frags.rnd);
@@ -202,6 +210,7 @@ static int ip6_frag_queue(struct frag_queue *fq, struct sk_buff *skb, 
	struct net_device *dev;

	int offset, end;

	struct net *net = dev_net(skb_dst(skb)->dev);

	u8 ecn;



	if (fq->q.last_in & INET_FRAG_COMPLETE)

		goto err;
@@ -219,6 +228,8 @@ static int ip6_frag_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,
@@ -319,6 +330,7 @@ found: 
	}

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

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

	fq->ecn |= ecn;

	add_frag_mem_limit(&fq->q, skb->truesize);



	/* The first fragment.
@@ -362,9 +374,14 @@ static int ip6_frag_reasm(struct frag_queue *fq, struct sk_buff *prev, 
	int    payload_len;

	unsigned int nhoff;

	int sum_truesize;

	u8 ecn;



	inet_frag_kill(&fq->q, &ip6_frags);



	ecn = ip_frag_ecn_table[fq->ecn];

	if (unlikely(ecn == 0xff))

		goto out_fail;



	/* Make the one we just received the head. */

	if (prev) {

		head = prev->next;
@@ -463,6 +480,7 @@ static int ip6_frag_reasm(struct frag_queue *fq, struct sk_buff *prev, 
	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)->nhoff = nhoff;



	/* Yes, and fold redundant checksum back. 8) */
@@ -526,7 +544,8 @@ static int ipv6_frag_rcv(struct sk_buff *skb) 
		IP6_ADD_STATS_BH(net, ip6_dst_idev(skb_dst(skb)),

				 IPSTATS_MIB_REASMFAILS, evicted);



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

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

		     ip6_frag_ecn(hdr));

	if (fq != NULL) {

		int ret;

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