From cc5c00bbb44c5d68b883aa5cb9d01514a2525d94 Mon Sep 17 00:00:00 2001 From: Herbert Xu Date: Fri, 22 Nov 2013 10:31:29 +0800 Subject: gro: Only verify TCP checksums for candidates In some cases we may receive IP packets that are longer than their stated lengths. Such packets are never merged in GRO. However, we may end up computing their checksums incorrectly and end up allowing packets with a bogus checksum enter our stack with the checksum status set as verified. Since such packets are rare and not performance-critical, this patch simply skips the checksum verification for them. Reported-by: Alexander Duyck Signed-off-by: Herbert Xu Acked-by: Alexander Duyck Thanks, Acked-by: Eric Dumazet Signed-off-by: David S. Miller --- net/ipv4/tcp_offload.c | 5 +++++ 1 file changed, 5 insertions(+) (limited to 'net/ipv4/tcp_offload.c') diff --git a/net/ipv4/tcp_offload.c b/net/ipv4/tcp_offload.c index a2b68a108ea..55aeec93014 100644 --- a/net/ipv4/tcp_offload.c +++ b/net/ipv4/tcp_offload.c @@ -276,6 +276,10 @@ static struct sk_buff **tcp4_gro_receive(struct sk_buff **head, struct sk_buff * __wsum wsum; __sum16 sum; + /* Don't bother verifying checksum if we're going to flush anyway. */ + if (NAPI_GRO_CB(skb)->flush) + goto skip_csum; + switch (skb->ip_summed) { case CHECKSUM_COMPLETE: if (!tcp_v4_check(skb_gro_len(skb), iph->saddr, iph->daddr, @@ -301,6 +305,7 @@ flush: break; } +skip_csum: return tcp_gro_receive(head, skb); } -- cgit v1.2.3-70-g09d2 From b8ee93ba80b5a0b6c3c06b65c34dd1276f16c047 Mon Sep 17 00:00:00 2001 From: Herbert Xu Date: Fri, 22 Nov 2013 10:32:11 +0800 Subject: gro: Clean up tcpX_gro_receive checksum verification This patch simplifies the checksum verification in tcpX_gro_receive by reusing the CHECKSUM_COMPLETE code for CHECKSUM_NONE. All it does for CHECKSUM_NONE is compute the partial checksum and then treat it as if it came from the hardware (CHECKSUM_COMPLETE). Signed-off-by: Herbert Xu Cheers, Acked-by: Eric Dumazet Signed-off-by: David S. Miller --- net/ipv4/tcp_offload.c | 26 ++++++++++---------------- net/ipv6/tcpv6_offload.c | 27 ++++++++++----------------- 2 files changed, 20 insertions(+), 33 deletions(-) (limited to 'net/ipv4/tcp_offload.c') diff --git a/net/ipv4/tcp_offload.c b/net/ipv4/tcp_offload.c index 55aeec93014..05606353c7e 100644 --- a/net/ipv4/tcp_offload.c +++ b/net/ipv4/tcp_offload.c @@ -274,35 +274,29 @@ static struct sk_buff **tcp4_gro_receive(struct sk_buff **head, struct sk_buff * { const struct iphdr *iph = skb_gro_network_header(skb); __wsum wsum; - __sum16 sum; /* Don't bother verifying checksum if we're going to flush anyway. */ if (NAPI_GRO_CB(skb)->flush) goto skip_csum; + wsum = skb->csum; + switch (skb->ip_summed) { + case CHECKSUM_NONE: + wsum = skb_checksum(skb, skb_gro_offset(skb), skb_gro_len(skb), + 0); + + /* fall through */ + case CHECKSUM_COMPLETE: if (!tcp_v4_check(skb_gro_len(skb), iph->saddr, iph->daddr, - skb->csum)) { + wsum)) { skb->ip_summed = CHECKSUM_UNNECESSARY; break; } -flush: + NAPI_GRO_CB(skb)->flush = 1; return NULL; - - case CHECKSUM_NONE: - wsum = csum_tcpudp_nofold(iph->saddr, iph->daddr, - skb_gro_len(skb), IPPROTO_TCP, 0); - sum = csum_fold(skb_checksum(skb, - skb_gro_offset(skb), - skb_gro_len(skb), - wsum)); - if (sum) - goto flush; - - skb->ip_summed = CHECKSUM_UNNECESSARY; - break; } skip_csum: diff --git a/net/ipv6/tcpv6_offload.c b/net/ipv6/tcpv6_offload.c index 71923d14127..6d18157dc32 100644 --- a/net/ipv6/tcpv6_offload.c +++ b/net/ipv6/tcpv6_offload.c @@ -37,36 +37,29 @@ static struct sk_buff **tcp6_gro_receive(struct sk_buff **head, { const struct ipv6hdr *iph = skb_gro_network_header(skb); __wsum wsum; - __sum16 sum; /* Don't bother verifying checksum if we're going to flush anyway. */ if (NAPI_GRO_CB(skb)->flush) goto skip_csum; + wsum = skb->csum; + switch (skb->ip_summed) { + case CHECKSUM_NONE: + wsum = skb_checksum(skb, skb_gro_offset(skb), skb_gro_len(skb), + wsum); + + /* fall through */ + case CHECKSUM_COMPLETE: if (!tcp_v6_check(skb_gro_len(skb), &iph->saddr, &iph->daddr, - skb->csum)) { + wsum)) { skb->ip_summed = CHECKSUM_UNNECESSARY; break; } -flush: + NAPI_GRO_CB(skb)->flush = 1; return NULL; - - case CHECKSUM_NONE: - wsum = ~csum_unfold(csum_ipv6_magic(&iph->saddr, &iph->daddr, - skb_gro_len(skb), - IPPROTO_TCP, 0)); - sum = csum_fold(skb_checksum(skb, - skb_gro_offset(skb), - skb_gro_len(skb), - wsum)); - if (sum) - goto flush; - - skb->ip_summed = CHECKSUM_UNNECESSARY; - break; } skip_csum: -- cgit v1.2.3-70-g09d2