[PATCH v4 net-next v4 5/6] net: create tcp_gro_header_pull helper function

Felix Fietkau
2024-04-27T18:23:15Z

Pull the code out of tcp_gro_receive in order to access the tcp header
from tcp4/6_gro_receive.

Reviewed-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Felix Fietkau <nbd@nbd.name>
---
include/net/tcp.h | 4 ++-
net/ipv4/tcp_offload.c | 55 +++++++++++++++++++++++++---------------
net/ipv6/tcpv6_offload.c | 18 +++++++++----
3 files changed, 50 insertions(+), 27 deletions(-)

diff --git a/include/net/tcp.h b/include/net/tcp.h
index 9f08ecab26e0..bf392c1fbadc 100644
--- a/include/net/tcp.h
+++ b/include/net/tcp.h
@@ -2199,8 +2199,10 @@ void tcp_v4_destroy_sock(struct sock *sk);

struct sk_buff *tcp_gso_segment(struct sk_buff *skb,
netdev_features_t features);
+struct tcphdr *tcp_gro_pull_header(struct sk_buff *skb);
struct sk_buff *tcp_gro_lookup(struct list_head *head, struct tcphdr *th);
-struct sk_buff *tcp_gro_receive(struct list_head *head, struct sk_buff *skb);
+struct sk_buff *tcp_gro_receive(struct list_head *head, struct sk_buff *skb,
+ struct tcphdr *th);
INDIRECT_CALLABLE_DECLARE(int tcp4_gro_complete(struct sk_buff *skb, int thoff));
INDIRECT_CALLABLE_DECLARE(struct sk_buff *tcp4_gro_receive(struct list_head *head, struct sk_buff *skb));
INDIRECT_CALLABLE_DECLARE(int tcp6_gro_complete(struct sk_buff *skb, int thoff));
diff --git a/net/ipv4/tcp_offload.c b/net/ipv4/tcp_offload.c
index 4a194a9d36cd..87ae9808e260 100644
--- a/net/ipv4/tcp_offload.c
+++ b/net/ipv4/tcp_offload.c
@@ -266,40 +266,46 @@ struct sk_buff *tcp_gro_lookup(struct list_head *head, struct tcphdr *th)
return NULL;
}

-struct sk_buff *tcp_gro_receive(struct list_head *head, struct sk_buff *skb)
+struct tcphdr *tcp_gro_pull_header(struct sk_buff *skb)
{
- struct sk_buff *pp = NULL;
- struct sk_buff *p;
+ unsigned int thlen, hlen, off;
struct tcphdr *th;
- struct tcphdr *th2;
- unsigned int len;
- unsigned int thlen;
- __be32 flags;
- unsigned int mss = 1;
- unsigned int hlen;
- unsigned int off;
- int flush = 1;
- int i;

off = skb_gro_offset(skb);
hlen = off + sizeof(*th);
th = skb_gro_header(skb, hlen, off);
if (unlikely(!th))
- goto out;
+ return NULL;

thlen = th->doff * 4;
if (thlen < sizeof(*th))
- goto out;
+ return NULL;

hlen = off + thlen;
if (!skb_gro_may_pull(skb, hlen)) {
th = skb_gro_header_slow(skb, hlen, off);
if (unlikely(!th))
- goto out;
+ return NULL;
}

skb_gro_pull(skb, thlen);

+ return th;
+}
+
+struct sk_buff *tcp_gro_receive(struct list_head *head, struct sk_buff *skb,
+ struct tcphdr *th)
+{
+ unsigned int thlen = th->doff * 4;
+ struct sk_buff *pp = NULL;
+ struct sk_buff *p;
+ struct tcphdr *th2;
+ unsigned int len;
+ __be32 flags;
+ unsigned int mss = 1;
+ int flush = 1;
+ int i;
+
len = skb_gro_len(skb);
flags = tcp_flag_word(th);

@@ -376,7 +382,6 @@ struct sk_buff *tcp_gro_receive(struct list_head *head, struct sk_buff *skb)
if (p && (!NAPI_GRO_CB(skb)->same_flow || flush))
pp = p;

-out:
NAPI_GRO_CB(skb)->flush |= (flush != 0);

return pp;
@@ -405,15 +410,23 @@ EXPORT_SYMBOL(tcp_gro_complete);
INDIRECT_CALLABLE_SCOPE
struct sk_buff *tcp4_gro_receive(struct list_head *head, struct sk_buff *skb)
{
+ struct tcphdr *th;
+
/* Don't bother verifying checksum if we're going to flush anyway. */
if (!NAPI_GRO_CB(skb)->flush &&
skb_gro_checksum_validate(skb, IPPROTO_TCP,
- inet_gro_compute_pseudo)) {
- NAPI_GRO_CB(skb)->flush = 1;
- return NULL;
- }
+ inet_gro_compute_pseudo))
+ goto flush;
+
+ th = tcp_gro_pull_header(skb);
+ if (!th)
+ goto flush;

- return tcp_gro_receive(head, skb);
+ return tcp_gro_receive(head, skb, th);
+
+flush:
+ NAPI_GRO_CB(skb)->flush = 1;
+ return NULL;
}

INDIRECT_CALLABLE_SCOPE int tcp4_gro_complete(struct sk_buff *skb, int thoff)
diff --git a/net/ipv6/tcpv6_offload.c b/net/ipv6/tcpv6_offload.c
index 575e2743e331..e73a4f74fd96 100644
--- a/net/ipv6/tcpv6_offload.c
+++ b/net/ipv6/tcpv6_offload.c
@@ -16,15 +16,23 @@
INDIRECT_CALLABLE_SCOPE
struct sk_buff *tcp6_gro_receive(struct list_head *head, struct sk_buff *skb)
{
+ struct tcphdr *th;
+
/* Don't bother verifying checksum if we're going to flush anyway. */
if (!NAPI_GRO_CB(skb)->flush &&
skb_gro_checksum_validate(skb, IPPROTO_TCP,
- ip6_gro_compute_pseudo)) {
- NAPI_GRO_CB(skb)->flush = 1;
- return NULL;
- }
+ ip6_gro_compute_pseudo))
+ goto flush;
+
+ th = tcp_gro_pull_header(skb);
+ if (!th)
+ goto flush;
+
+ return tcp_gro_receive(head, skb, th);

- return tcp_gro_receive(head, skb);
+flush:
+ NAPI_GRO_CB(skb)->flush = 1;
+ return NULL;
}

INDIRECT_CALLABLE_SCOPE int tcp6_gro_complete(struct sk_buff *skb, int thoff)
--
2.44.0