[PATCH 4.2.y-ckt 268/268] ipv6: update skb->csum when CE mark is propagated
From: Kamal Mostafa <hidden>
Date: 2016-01-27 20:41:12
Also in:
lkml
Subsystem:
networking [general], networking [ipsec], the rest · Maintainers:
"David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Steffen Klassert, Herbert Xu, Linus Torvalds
4.2.8-ckt3 -stable review patch. If anyone has any objections, please let me know. ---8<------------------------------------------------------------ From: Eric Dumazet <edumazet@google.com> [ Upstream commit 34ae6a1aa0540f0f781dd265366036355fdc8930 ] 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> Signed-off-by: Kamal Mostafa <redacted> --- include/net/inet_ecn.h | 19 ++++++++++++++++--- net/ipv6/xfrm6_mode_tunnel.c | 2 +- 2 files changed, 17 insertions(+), 4 deletions(-)
diff --git a/include/net/inet_ecn.h b/include/net/inet_ecn.h
index 84b2083..0dc0a51 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 901ef6f..5266ad2 100644
--- a/net/ipv6/xfrm6_mode_tunnel.c
+++ b/net/ipv6/xfrm6_mode_tunnel.c@@ -24,7 +24,7 @@ static inline void ipip6_ecn_decapsulate(struct sk_buff *skb) struct ipv6hdr *inner_iph = ipipv6_hdr(skb); if (INET_ECN_is_ce(ipv6_get_dsfield(outer_iph))) - IP6_ECN_set_ce(inner_iph); + IP6_ECN_set_ce(skb, inner_iph); } /* Add encapsulation header.
--
1.9.1