From db3c6139e6ead91b42e7c2ad044ed8beaee884e6 Mon Sep 17 00:00:00 2001 From: Daniel Borkmann Date: Fri, 4 Mar 2016 15:15:07 +0100 Subject: bpf, vxlan, geneve, gre: fix usage of dst_cache on xmit The assumptions from commit 0c1d70af924b ("net: use dst_cache for vxlan device"), 468dfffcd762 ("geneve: add dst caching support") and 3c1cb4d2604c ("net/ipv4: add dst cache support for gre lwtunnels") on dst_cache usage when ip_tunnel_info is used is unfortunately not always valid as assumed. While it seems correct for ip_tunnel_info front-ends such as OVS, eBPF however can fill in ip_tunnel_info for consumers like vxlan, geneve or gre with different remote dsts, tos, etc, therefore they cannot be assumed as packet independent. Right now vxlan, geneve, gre would cache the dst for eBPF and every packet would reuse the same entry that was first created on the initial route lookup. eBPF doesn't store/cache the ip_tunnel_info, so each skb may have a different one. Fix it by adding a flag that checks the ip_tunnel_info. Also the !tos test in vxlan needs to be handeled differently in this context as it is currently inferred from ip_tunnel_info as well if present. ip_tunnel_dst_cache_usable() helper is added for the three tunnel cases, which checks if we can use dst cache. Fixes: 0c1d70af924b ("net: use dst_cache for vxlan device") Fixes: 468dfffcd762 ("geneve: add dst caching support") Fixes: 3c1cb4d2604c ("net/ipv4: add dst cache support for gre lwtunnels") Signed-off-by: Daniel Borkmann Acked-by: Paolo Abeni Acked-by: Hannes Frederic Sowa Signed-off-by: David S. Miller --- net/ipv4/ip_gre.c | 10 ++++++---- 1 file changed, 6 insertions(+), 4 deletions(-) (limited to 'net/ipv4/ip_gre.c') diff --git a/net/ipv4/ip_gre.c b/net/ipv4/ip_gre.c index 202437d6087b..31936d387cfd 100644 --- a/net/ipv4/ip_gre.c +++ b/net/ipv4/ip_gre.c @@ -527,11 +527,12 @@ static void gre_fb_xmit(struct sk_buff *skb, struct net_device *dev) { struct ip_tunnel_info *tun_info; const struct ip_tunnel_key *key; + struct rtable *rt = NULL; struct flowi4 fl; - struct rtable *rt; int min_headroom; int tunnel_hlen; __be16 df, flags; + bool use_cache; int err; tun_info = skb_tunnel_info(skb); @@ -540,13 +541,14 @@ static void gre_fb_xmit(struct sk_buff *skb, struct net_device *dev) goto err_free_skb; key = &tun_info->key; - rt = !skb->mark ? dst_cache_get_ip4(&tun_info->dst_cache, &fl.saddr) : - NULL; + use_cache = ip_tunnel_dst_cache_usable(skb, tun_info); + if (use_cache) + rt = dst_cache_get_ip4(&tun_info->dst_cache, &fl.saddr); if (!rt) { rt = gre_get_rt(skb, dev, &fl, key); if (IS_ERR(rt)) goto err_free_skb; - if (!skb->mark) + if (use_cache) dst_cache_set_ip4(&tun_info->dst_cache, &rt->dst, fl.saddr); } -- cgit v1.2.3