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| author |   Edward Cree <ecree@solarflare.com> | 2016-02-11 20:48:04 +0000 |
|---|---|---|
| committer |   David S. Miller <davem@davemloft.net> | 2016-02-12 05:52:15 -0500 |
| commit | 179bc67f69b6cb53ad68cfdec5a917c2a2248355 (patch) | |
| tree | 9c3251d5226c75826a19f10d33e3b7279d6f0969 /net/ipv4/udp.c | |
| parent | Merge branch 'tcp_dccp_ports' (diff) | |
| download | linux-dev-179bc67f69b6cb53ad68cfdec5a917c2a2248355.tar.xz linux-dev-179bc67f69b6cb53ad68cfdec5a917c2a2248355.zip | |
net: local checksum offload for encapsulation
The arithmetic properties of the ones-complement checksum mean that a
correctly checksummed inner packet, including its checksum, has a ones
complement sum depending only on whatever value was used to initialise
the checksum field before checksumming (in the case of TCP and UDP,
this is the ones complement sum of the pseudo header, complemented).
Consequently, if we are going to offload the inner checksum with
CHECKSUM_PARTIAL, we can compute the outer checksum based only on the
packed data not covered by the inner checksum, and the initial value of
the inner checksum field.
Signed-off-by: Edward Cree <ecree@solarflare.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/ipv4/udp.c')
| -rw-r--r-- | net/ipv4/udp.c | 20 |
1 files changed, 10 insertions, 10 deletions
diff --git a/net/ipv4/udp.c b/net/ipv4/udp.c index ac3cedb25a9f..a59341cf483e 100644 --- a/net/ipv4/udp.c +++ b/net/ipv4/udp.c @@ -848,16 +848,18 @@ void udp_set_csum(bool nocheck, struct sk_buff *skb, { struct udphdr *uh = udp_hdr(skb); - if (nocheck) + if (nocheck) { uh->check = 0; - else if (skb_is_gso(skb)) + } else if (skb_is_gso(skb)) { uh->check = ~udp_v4_check(len, saddr, daddr, 0); - else if (skb_dst(skb) && skb_dst(skb)->dev && - (skb_dst(skb)->dev->features & - (NETIF_F_IP_CSUM | NETIF_F_HW_CSUM))) { - - BUG_ON(skb->ip_summed == CHECKSUM_PARTIAL); - + } else if (skb->ip_summed == CHECKSUM_PARTIAL) { + uh->check = 0; + uh->check = udp_v4_check(len, saddr, daddr, lco_csum(skb)); + if (uh->check == 0) + uh->check = CSUM_MANGLED_0; + } else if (skb_dst(skb) && skb_dst(skb)->dev && + (skb_dst(skb)->dev->features & + (NETIF_F_IP_CSUM | NETIF_F_HW_CSUM))) { skb->ip_summed = CHECKSUM_PARTIAL; skb->csum_start = skb_transport_header(skb) - skb->head; skb->csum_offset = offsetof(struct udphdr, check); @@ -865,8 +867,6 @@ void udp_set_csum(bool nocheck, struct sk_buff *skb, } else { __wsum csum; - BUG_ON(skb->ip_summed == CHECKSUM_PARTIAL); - uh->check = 0; csum = skb_checksum(skb, 0, len, 0); uh->check = udp_v4_check(len, saddr, daddr, csum); |