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| author | Ulrich Weber <uweber@astaro.com> | 2010-02-26 04:34:49 -0800 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2010-02-26 04:34:49 -0800 |
| commit | 14f3ad6f4a12495b32b0dd743bc7179f36658208 (patch) | |
| tree | bff2b347d1a1755955ba1b37c561b1bff2f6d861 /net/ipv6 | |
| parent | fbf219f1c89b15e90ec2db5a3e9636376dc623db (diff) | |
| download | linux-14f3ad6f4a12495b32b0dd743bc7179f36658208.tar.gz linux-14f3ad6f4a12495b32b0dd743bc7179f36658208.tar.bz2 linux-14f3ad6f4a12495b32b0dd743bc7179f36658208.zip | |
ipv6: Use 1280 as min MTU for ipv6 forwarding
Clients will set their MTU to 1280 if they receive a
ICMPV6_PKT_TOOBIG message with an MTU less than 1280.
To allow encapsulating of packets over a 1280 link
we should always accept packets with a size of 1280
for forwarding even if the path has a lower MTU and
fragment the encapsulated packets afterwards.
In case a forwarded packet is not going to be encapsulated
a ICMPV6_PKT_TOOBIG msg will still be send by ip6_fragment()
with the correct MTU.
Signed-off-by: Ulrich Weber <uweber@astaro.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/ipv6')
| -rw-r--r-- | net/ipv6/ip6_output.c | 12 |
1 files changed, 8 insertions, 4 deletions
diff --git a/net/ipv6/ip6_output.c b/net/ipv6/ip6_output.c index 1a5fe9ad1947..dabf108ad811 100644 --- a/net/ipv6/ip6_output.c +++ b/net/ipv6/ip6_output.c @@ -402,6 +402,7 @@ int ip6_forward(struct sk_buff *skb) struct ipv6hdr *hdr = ipv6_hdr(skb); struct inet6_skb_parm *opt = IP6CB(skb); struct net *net = dev_net(dst->dev); + u32 mtu; if (net->ipv6.devconf_all->forwarding == 0) goto error; @@ -508,10 +509,14 @@ int ip6_forward(struct sk_buff *skb) } } - if (skb->len > dst_mtu(dst)) { + mtu = dst_mtu(dst); + if (mtu < IPV6_MIN_MTU) + mtu = IPV6_MIN_MTU; + + if (skb->len > mtu) { /* Again, force OUTPUT device used as source address */ skb->dev = dst->dev; - icmpv6_send(skb, ICMPV6_PKT_TOOBIG, 0, dst_mtu(dst)); + icmpv6_send(skb, ICMPV6_PKT_TOOBIG, 0, mtu); IP6_INC_STATS_BH(net, ip6_dst_idev(dst), IPSTATS_MIB_INTOOBIGERRORS); IP6_INC_STATS_BH(net, @@ -621,8 +626,7 @@ static int ip6_fragment(struct sk_buff *skb, int (*output)(struct sk_buff *)) mtu = ip6_skb_dst_mtu(skb); /* We must not fragment if the socket is set to force MTU discovery - * or if the skb it not generated by a local socket. (This last - * check should be redundant, but it's free.) + * or if the skb it not generated by a local socket. */ if (!skb->local_df) { skb->dev = skb_dst(skb)->dev; |