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authorEric Dumazet <edumazet@google.com>2016-01-15 15:56:56 +0300
committerDavid S. Miller <davem@davemloft.net>2016-01-15 23:07:23 +0300
commit34ae6a1aa0540f0f781dd265366036355fdc8930 (patch)
tree11df908434ac0da470b34a08fd254df1429c4e65
parent113c74d83eef870e43a0d9279044e9d5435f0d07 (diff)
downloadlinux-34ae6a1aa0540f0f781dd265366036355fdc8930.tar.xz
ipv6: update skb->csum when CE mark is propagated
When a tunnel decapsulates the outer header, it has to comply with RFC 6080 and eventually propagate CE mark into inner header. It turns out IP6_ECN_set_ce() does not correctly update skb->csum for CHECKSUM_COMPLETE packets, triggering infamous "hw csum failure" messages and stack traces. Signed-off-by: Eric Dumazet <edumazet@google.com> Acked-by: Herbert Xu <herbert@gondor.apana.org.au> Signed-off-by: David S. Miller <davem@davemloft.net>
-rw-r--r--include/net/inet_ecn.h19
-rw-r--r--net/ipv6/xfrm6_mode_tunnel.c2
2 files changed, 17 insertions, 4 deletions
diff --git a/include/net/inet_ecn.h b/include/net/inet_ecn.h
index 84b20835b736..0dc0a51da38f 100644
--- a/include/net/inet_ecn.h
+++ b/include/net/inet_ecn.h
@@ -111,11 +111,24 @@ static inline void ipv4_copy_dscp(unsigned int dscp, struct iphdr *inner)
struct ipv6hdr;
-static inline int IP6_ECN_set_ce(struct ipv6hdr *iph)
+/* Note:
+ * IP_ECN_set_ce() has to tweak IPV4 checksum when setting CE,
+ * meaning both changes have no effect on skb->csum if/when CHECKSUM_COMPLETE
+ * In IPv6 case, no checksum compensates the change in IPv6 header,
+ * so we have to update skb->csum.
+ */
+static inline int IP6_ECN_set_ce(struct sk_buff *skb, struct ipv6hdr *iph)
{
+ __be32 from, to;
+
if (INET_ECN_is_not_ect(ipv6_get_dsfield(iph)))
return 0;
- *(__be32*)iph |= htonl(INET_ECN_CE << 20);
+
+ from = *(__be32 *)iph;
+ to = from | htonl(INET_ECN_CE << 20);
+ *(__be32 *)iph = to;
+ if (skb->ip_summed == CHECKSUM_COMPLETE)
+ skb->csum = csum_add(csum_sub(skb->csum, from), to);
return 1;
}
@@ -142,7 +155,7 @@ static inline int INET_ECN_set_ce(struct sk_buff *skb)
case cpu_to_be16(ETH_P_IPV6):
if (skb_network_header(skb) + sizeof(struct ipv6hdr) <=
skb_tail_pointer(skb))
- return IP6_ECN_set_ce(ipv6_hdr(skb));
+ return IP6_ECN_set_ce(skb, ipv6_hdr(skb));
break;
}
diff --git a/net/ipv6/xfrm6_mode_tunnel.c b/net/ipv6/xfrm6_mode_tunnel.c
index f7fbdbabe50e..372855eeaf42 100644
--- a/net/ipv6/xfrm6_mode_tunnel.c
+++ b/net/ipv6/xfrm6_mode_tunnel.c
@@ -23,7 +23,7 @@ static inline void ipip6_ecn_decapsulate(struct sk_buff *skb)
struct ipv6hdr *inner_iph = ipipv6_hdr(skb);
if (INET_ECN_is_ce(XFRM_MODE_SKB_CB(skb)->tos))
- IP6_ECN_set_ce(inner_iph);
+ IP6_ECN_set_ce(skb, inner_iph);
}
/* Add encapsulation header.