From d52eb0d46f3606b9de9965cebb2beb2202a0dc62 Mon Sep 17 00:00:00 2001 From: Paul Durrant Date: Wed, 11 Dec 2013 16:37:40 +0000 Subject: [PATCH] xen-netback: make sure skb linear area covers checksum field skb_partial_csum_set requires that the linear area of the skb covers the checksum field. The checksum setup code in netback was only doing that pullup in the case when the pseudo header checksum was being recalculated though. This patch makes that pullup unconditional. (I pullup the whole transport header just for simplicity; the requirement is only for the check field but in the case of UDP this is the last field in the header and in the case of TCP it's the last but one). The lack of pullup manifested as failures running Microsoft HCK network tests on a pair of Windows 8 VMs and it has been verified that this patch fixes the problem. Suggested-by: Jan Beulich Signed-off-by: Paul Durrant Cc: Wei Liu Cc: Ian Campbell Cc: David Vrabel Reviewed-by: Jan Beulich Signed-off-by: David S. Miller --- drivers/net/xen-netback/netback.c | 60 ++++++++++++++++++--------------------- 1 file changed, 28 insertions(+), 32 deletions(-) diff --git a/drivers/net/xen-netback/netback.c b/drivers/net/xen-netback/netback.c index acf1392..d158fc4 100644 --- a/drivers/net/xen-netback/netback.c +++ b/drivers/net/xen-netback/netback.c @@ -1199,42 +1199,40 @@ static int checksum_setup_ip(struct xenvif *vif, struct sk_buff *skb, switch (ip_hdr(skb)->protocol) { case IPPROTO_TCP: + err = maybe_pull_tail(skb, + off + sizeof(struct tcphdr), + MAX_IP_HDR_LEN); + if (err < 0) + goto out; + if (!skb_partial_csum_set(skb, off, offsetof(struct tcphdr, check))) goto out; - if (recalculate_partial_csum) { - err = maybe_pull_tail(skb, - off + sizeof(struct tcphdr), - MAX_IP_HDR_LEN); - if (err < 0) - goto out; - + if (recalculate_partial_csum) tcp_hdr(skb)->check = ~csum_tcpudp_magic(ip_hdr(skb)->saddr, ip_hdr(skb)->daddr, skb->len - off, IPPROTO_TCP, 0); - } break; case IPPROTO_UDP: + err = maybe_pull_tail(skb, + off + sizeof(struct udphdr), + MAX_IP_HDR_LEN); + if (err < 0) + goto out; + if (!skb_partial_csum_set(skb, off, offsetof(struct udphdr, check))) goto out; - if (recalculate_partial_csum) { - err = maybe_pull_tail(skb, - off + sizeof(struct udphdr), - MAX_IP_HDR_LEN); - if (err < 0) - goto out; - + if (recalculate_partial_csum) udp_hdr(skb)->check = ~csum_tcpudp_magic(ip_hdr(skb)->saddr, ip_hdr(skb)->daddr, skb->len - off, IPPROTO_UDP, 0); - } break; default: goto out; @@ -1342,42 +1340,40 @@ static int checksum_setup_ipv6(struct xenvif *vif, struct sk_buff *skb, switch (nexthdr) { case IPPROTO_TCP: + err = maybe_pull_tail(skb, + off + sizeof(struct tcphdr), + MAX_IPV6_HDR_LEN); + if (err < 0) + goto out; + if (!skb_partial_csum_set(skb, off, offsetof(struct tcphdr, check))) goto out; - if (recalculate_partial_csum) { - err = maybe_pull_tail(skb, - off + sizeof(struct tcphdr), - MAX_IPV6_HDR_LEN); - if (err < 0) - goto out; - + if (recalculate_partial_csum) tcp_hdr(skb)->check = ~csum_ipv6_magic(&ipv6_hdr(skb)->saddr, &ipv6_hdr(skb)->daddr, skb->len - off, IPPROTO_TCP, 0); - } break; case IPPROTO_UDP: + err = maybe_pull_tail(skb, + off + sizeof(struct udphdr), + MAX_IPV6_HDR_LEN); + if (err < 0) + goto out; + if (!skb_partial_csum_set(skb, off, offsetof(struct udphdr, check))) goto out; - if (recalculate_partial_csum) { - err = maybe_pull_tail(skb, - off + sizeof(struct udphdr), - MAX_IPV6_HDR_LEN); - if (err < 0) - goto out; - + if (recalculate_partial_csum) udp_hdr(skb)->check = ~csum_ipv6_magic(&ipv6_hdr(skb)->saddr, &ipv6_hdr(skb)->daddr, skb->len - off, IPPROTO_UDP, 0); - } break; default: goto out; -- 2.7.4