Re: [PATCH] bpf, sockmap: Do not read sk_receive_queue in tcp_bpf_recvmsg if strparser enabled

Jakub Sitnicki wrote:

On Fri, Oct 15, 2021 at 10:01 AM CEST, Liu Jian wrote:

quoted

If the strparser function of sk is turned on, all received data needs to
be processed by strparser first.

Fixes: 604326b41a6fb ("bpf, sockmap: convert to generic sk_msg interface")
Signed-off-by: Liu Jian <redacted>
---

[...]

quoted

 net/core/skmsg.c      | 5 +++++
 net/ipv4/tcp_bpf.c    | 9 ++++++---
 3 files changed, 17 insertions(+), 3 deletions(-)

diff --git a/include/linux/skmsg.h b/include/linux/skmsg.h
index 94e2a1f6e58d..25e92dff04aa 100644
--- a/include/linux/skmsg.h
+++ b/include/linux/skmsg.h

@@ -390,6 +390,7 @@ void sk_psock_stop(struct sk_psock *psock, bool wait);
 int sk_psock_init_strp(struct sock *sk, struct sk_psock *psock);
 void sk_psock_start_strp(struct sock *sk, struct sk_psock *psock);
 void sk_psock_stop_strp(struct sock *sk, struct sk_psock *psock);
+bool sk_psock_strparser_started(struct sock *sk);
 #else
 static inline int sk_psock_init_strp(struct sock *sk, struct sk_psock *psock)
 {

@@ -403,6 +404,11 @@ static inline void sk_psock_start_strp(struct sock *sk, struct sk_psock *psock)
 static inline void sk_psock_stop_strp(struct sock *sk, struct sk_psock *psock)
 {
 }
+
+static inline bool sk_psock_strparser_started(struct sock *sk)
+{
+	return false;
+}
 #endif
 
 void sk_psock_start_verdict(struct sock *sk, struct sk_psock *psock);

diff --git a/net/core/skmsg.c b/net/core/skmsg.c
index e85b7f8491b9..dd64ef854f3e 100644
--- a/net/core/skmsg.c
+++ b/net/core/skmsg.c

@@ -1105,6 +1105,11 @@ void sk_psock_start_strp(struct sock *sk, struct sk_psock *psock)
 	sk->sk_write_space = sk_psock_write_space;
 }
 
+bool sk_psock_strparser_started(struct sock *sk)
+{
+	return sk->sk_data_ready == sk_psock_strp_data_ready;

What if kTLS is configured on the socket? I think this check won't work then.

Liu, did you see this. I think its a bit cleaner, avoids the extra parser
check in hotpath, and should solve the issue?

https://patchwork.kernel.org/project/netdevbpf/patch/20211011191647.418704-3-john.fastabend@gmail.com/

I think it should also address Jakub's concern.

Thanks,
John

quoted

+}
+
 void sk_psock_stop_strp(struct sock *sk, struct sk_psock *psock)
 {
 	if (!psock->saved_data_ready)

[...]