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authorJerry Chu <hkchu@google.com>2013-12-11 20:53:45 -0800
committerDavid S. Miller <davem@davemloft.net>2013-12-12 13:47:53 -0500
commit299603e8370a93dd5d8e8d800f0dff1ce2c53d36 (patch)
tree2a10106aabe88c278a0cd02b93af1add04f5ffcc /net/ipv4/tcp_offload.c
parenta46dc748caea185d4d0978280a1af0112bf6a8f8 (diff)
downloadlinux-299603e8370a93dd5d8e8d800f0dff1ce2c53d36.tar.bz2
net-gro: Prepare GRO stack for the upcoming tunneling support
This patch modifies the GRO stack to avoid the use of "network_header" and associated macros like ip_hdr() and ipv6_hdr() in order to allow an arbitary number of IP hdrs (v4 or v6) to be used in the encapsulation chain. This lays the foundation for various IP tunneling support (IP-in-IP, GRE, VXLAN, SIT,...) to be added later. With this patch, the GRO stack traversing now is mostly based on skb_gro_offset rather than special hdr offsets saved in skb (e.g., skb->network_header). As a result all but the top layer (i.e., the the transport layer) must have hdrs of the same length in order for a pkt to be considered for aggregation. Therefore when adding a new encap layer (e.g., for tunneling), one must check and skip flows (e.g., by setting NAPI_GRO_CB(p)->same_flow to 0) that have a different hdr length. Note that unlike the network header, the transport header can and will continue to be set by the GRO code since there will be at most one "transport layer" in the encap chain. Signed-off-by: H.K. Jerry Chu <hkchu@google.com> Suggested-by: Eric Dumazet <edumazet@google.com> Reviewed-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/ipv4/tcp_offload.c')
-rw-r--r--net/ipv4/tcp_offload.c9
1 files changed, 5 insertions, 4 deletions
diff --git a/net/ipv4/tcp_offload.c b/net/ipv4/tcp_offload.c
index 05606353c7e7..2658a27f540d 100644
--- a/net/ipv4/tcp_offload.c
+++ b/net/ipv4/tcp_offload.c
@@ -240,7 +240,7 @@ int tcp_gro_complete(struct sk_buff *skb)
{
struct tcphdr *th = tcp_hdr(skb);
- skb->csum_start = skb_transport_header(skb) - skb->head;
+ skb->csum_start = (unsigned char *)th - skb->head;
skb->csum_offset = offsetof(struct tcphdr, check);
skb->ip_summed = CHECKSUM_PARTIAL;
@@ -272,6 +272,7 @@ static int tcp_v4_gso_send_check(struct sk_buff *skb)
static struct sk_buff **tcp4_gro_receive(struct sk_buff **head, struct sk_buff *skb)
{
+ /* Use the IP hdr immediately proceeding for this transport */
const struct iphdr *iph = skb_gro_network_header(skb);
__wsum wsum;
@@ -303,13 +304,13 @@ skip_csum:
return tcp_gro_receive(head, skb);
}
-static int tcp4_gro_complete(struct sk_buff *skb)
+static int tcp4_gro_complete(struct sk_buff *skb, int thoff)
{
const struct iphdr *iph = ip_hdr(skb);
struct tcphdr *th = tcp_hdr(skb);
- th->check = ~tcp_v4_check(skb->len - skb_transport_offset(skb),
- iph->saddr, iph->daddr, 0);
+ th->check = ~tcp_v4_check(skb->len - thoff, iph->saddr,
+ iph->daddr, 0);
skb_shinfo(skb)->gso_type = SKB_GSO_TCPV4;
return tcp_gro_complete(skb);