From c7ba65d7b64984ff371cb5630b36af23506c50d5 Mon Sep 17 00:00:00 2001 From: Florian Westphal Date: Mon, 5 May 2014 15:00:43 +0200 Subject: net: ip: push gso skb forwarding handling down the stack Doing the segmentation in the forward path has one major drawback: When using virtio, we may process gso udp packets coming from host network stack. In that case, netfilter POSTROUTING will see one packet with udp header followed by multiple ip fragments. Delay the segmentation and do it after POSTROUTING invocation to avoid this. Fixes: fe6cc55f3a9 ("net: ip, ipv6: handle gso skbs in forwarding path") Signed-off-by: Florian Westphal Signed-off-by: David S. Miller --- net/ipv4/ip_forward.c | 50 -------------------------------------------------- 1 file changed, 50 deletions(-) (limited to 'net/ipv4/ip_forward.c') diff --git a/net/ipv4/ip_forward.c b/net/ipv4/ip_forward.c index c29ae8371e44..6f111e48e11c 100644 --- a/net/ipv4/ip_forward.c +++ b/net/ipv4/ip_forward.c @@ -56,53 +56,6 @@ static bool ip_exceeds_mtu(const struct sk_buff *skb, unsigned int mtu) return true; } -static bool ip_gso_exceeds_dst_mtu(const struct sk_buff *skb) -{ - unsigned int mtu; - - if (skb->local_df || !skb_is_gso(skb)) - return false; - - mtu = ip_dst_mtu_maybe_forward(skb_dst(skb), true); - - /* if seglen > mtu, do software segmentation for IP fragmentation on - * output. DF bit cannot be set since ip_forward would have sent - * icmp error. - */ - return skb_gso_network_seglen(skb) > mtu; -} - -/* called if GSO skb needs to be fragmented on forward */ -static int ip_forward_finish_gso(struct sk_buff *skb) -{ - struct dst_entry *dst = skb_dst(skb); - netdev_features_t features; - struct sk_buff *segs; - int ret = 0; - - features = netif_skb_dev_features(skb, dst->dev); - segs = skb_gso_segment(skb, features & ~NETIF_F_GSO_MASK); - if (IS_ERR(segs)) { - kfree_skb(skb); - return -ENOMEM; - } - - consume_skb(skb); - - do { - struct sk_buff *nskb = segs->next; - int err; - - segs->next = NULL; - err = dst_output(segs); - - if (err && ret == 0) - ret = err; - segs = nskb; - } while (segs); - - return ret; -} static int ip_forward_finish(struct sk_buff *skb) { @@ -114,9 +67,6 @@ static int ip_forward_finish(struct sk_buff *skb) if (unlikely(opt->optlen)) ip_forward_options(skb); - if (ip_gso_exceeds_dst_mtu(skb)) - return ip_forward_finish_gso(skb); - return dst_output(skb); } -- cgit v1.2.3