From 299b0767642a65f0c5446ab6d35e6df0daf43d33 Mon Sep 17 00:00:00 2001 From: Steffen Klassert Date: Tue, 11 Oct 2011 01:43:33 +0000 Subject: [PATCH] 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: Steffen Klassert Signed-off-by: David S. Miller --- net/ipv6/ip6_output.c | 18 ++++++++++++------ net/ipv6/raw.c | 3 +-- 2 files changed, 13 insertions(+), 8 deletions(-) diff --git a/net/ipv6/ip6_output.c b/net/ipv6/ip6_output.c index 835c04b..1e20b64 100644 --- a/net/ipv6/ip6_output.c +++ b/net/ipv6/ip6_output.c @@ -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 @@ alloc_new_skb: 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 @@ alloc_new_skb: /* * 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 @@ alloc_new_skb: pskb_trim_unique(skb_prev, maxfraglen); } copy = datalen - transhdrlen - fraggap; + if (copy < 0) { err = -EINVAL; kfree_skb(skb); @@ -1448,6 +1453,7 @@ alloc_new_skb: length -= datalen - fraggap; transhdrlen = 0; exthdrlen = 0; + dst_exthdrlen = 0; csummode = CHECKSUM_NONE; /* diff --git a/net/ipv6/raw.c b/net/ipv6/raw.c index 3486f62..6f7824e 100644 --- a/net/ipv6/raw.c +++ b/net/ipv6/raw.c @@ -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); -- 2.7.4