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Commit 299b0767 authored by Steffen Klassert's avatar Steffen Klassert Committed by David S. Miller
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ipv6: Fix IPsec slowpath fragmentation problem 



ip6_append_data() builds packets based on the mtu from dst_mtu(rt->dst.path).
On IPsec the effective mtu is lower because we need to add the protocol
headers and trailers later when we do the IPsec transformations. So after
the IPsec transformations the packet might be too big, which leads to a
slowpath fragmentation then. This patch fixes this by building the packets
based on the lower IPsec mtu from dst_mtu(&rt->dst) and adapts the exthdr
handling to this.

Signed-off-by: default avatarSteffen Klassert <steffen.klassert@secunet.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent c113464d

net/ipv6/ip6_output.c

+12 −6
Original line number Diff line number Diff line
@@ -1193,6 +1193,7 @@ int ip6_append_data(struct sock *sk, int getfrag(void *from, char *to, 
	struct sk_buff *skb;

	unsigned int maxfraglen, fragheaderlen;

	int exthdrlen;

	int dst_exthdrlen;

	int hh_len;

	int mtu;

	int copy;
@@ -1248,7 +1249,7 @@ int ip6_append_data(struct sock *sk, int getfrag(void *from, char *to, 
		np->cork.hop_limit = hlimit;

		np->cork.tclass = tclass;

		mtu = np->pmtudisc == IPV6_PMTUDISC_PROBE ?

		      rt->dst.dev->mtu : dst_mtu(rt->dst.path);

		      rt->dst.dev->mtu : dst_mtu(&rt->dst);

		if (np->frag_size < mtu) {

			if (np->frag_size)

				mtu = np->frag_size;
@@ -1259,16 +1260,17 @@ int ip6_append_data(struct sock *sk, int getfrag(void *from, char *to, 
		cork->length = 0;

		sk->sk_sndmsg_page = NULL;

		sk->sk_sndmsg_off = 0;

		exthdrlen = rt->dst.header_len + (opt ? opt->opt_flen : 0) -

			    rt->rt6i_nfheader_len;

		exthdrlen = (opt ? opt->opt_flen : 0) - rt->rt6i_nfheader_len;

		length += exthdrlen;

		transhdrlen += exthdrlen;

		dst_exthdrlen = rt->dst.header_len;

	} else {

		rt = (struct rt6_info *)cork->dst;

		fl6 = &inet->cork.fl.u.ip6;

		opt = np->cork.opt;

		transhdrlen = 0;

		exthdrlen = 0;

		dst_exthdrlen = 0;

		mtu = cork->fragsize;

	}
@@ -1368,6 +1370,8 @@ int ip6_append_data(struct sock *sk, int getfrag(void *from, char *to, 
			else

				alloclen = datalen + fragheaderlen;



			alloclen += dst_exthdrlen;



			/*

			 * The last fragment gets additional space at tail.

			 * Note: we overallocate on fragments with MSG_MODE
@@ -1419,9 +1423,9 @@ int ip6_append_data(struct sock *sk, int getfrag(void *from, char *to, 
			/*

			 *	Find where to start putting bytes

			 */

			data = skb_put(skb, fraglen);

			skb_set_network_header(skb, exthdrlen);

			data += fragheaderlen;

			data = skb_put(skb, fraglen + dst_exthdrlen);

			skb_set_network_header(skb, exthdrlen + dst_exthdrlen);

			data += fragheaderlen + dst_exthdrlen;

			skb->transport_header = (skb->network_header +

						 fragheaderlen);

			if (fraggap) {
@@ -1434,6 +1438,7 @@ int ip6_append_data(struct sock *sk, int getfrag(void *from, char *to, 
				pskb_trim_unique(skb_prev, maxfraglen);

			}

			copy = datalen - transhdrlen - fraggap;



			if (copy < 0) {

				err = -EINVAL;

				kfree_skb(skb);
@@ -1448,6 +1453,7 @@ int ip6_append_data(struct sock *sk, int getfrag(void *from, char *to, 
			length -= datalen - fraggap;

			transhdrlen = 0;

			exthdrlen = 0;

			dst_exthdrlen = 0;

			csummode = CHECKSUM_NONE;



			/*

net/ipv6/raw.c

+1 −2
Original line number Diff line number Diff line
@@ -542,8 +542,7 @@ static int rawv6_push_pending_frames(struct sock *sk, struct flowi6 *fl6, 
		goto out;



	offset = rp->offset;

	total_len = inet_sk(sk)->cork.base.length - (skb_network_header(skb) -

						     skb->data);

	total_len = inet_sk(sk)->cork.base.length;

	if (offset >= total_len - 1) {

		err = -EINVAL;

		ip6_flush_pending_frames(sk);