netdev - [PATCH] bpf, sockmap: Do not read sk_receive_queue in tcp_bpf

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Date:   Fri, 15 Oct 2021 16:01:42 +0800
From:   Liu Jian <liujian56@...wei.com>
To:     <john.fastabend@...il.com>, <daniel@...earbox.net>,
        <jakub@...udflare.com>, <lmb@...udflare.com>,
        <edumazet@...gle.com>, <davem@...emloft.net>, <kuba@...nel.org>,
        <yoshfuji@...ux-ipv6.org>, <dsahern@...nel.org>, <ast@...nel.org>,
        <andrii@...nel.org>, <kafai@...com>, <songliubraving@...com>,
        <yhs@...com>, <kpsingh@...nel.org>, <netdev@...r.kernel.org>,
        <bpf@...r.kernel.org>
CC:     <liujian56@...wei.com>
Subject: [PATCH] bpf, sockmap: Do not read sk_receive_queue in tcp_bpf_recvmsg if strparser enabled

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 <liujian56@...wei.com>
---
 include/linux/skmsg.h | 6 ++++++
 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;
+}
+
 void sk_psock_stop_strp(struct sock *sk, struct sk_psock *psock)
 {
 	if (!psock->saved_data_ready)
diff --git a/net/ipv4/tcp_bpf.c b/net/ipv4/tcp_bpf.c
index 9d068153c316..17129b343966 100644
--- a/net/ipv4/tcp_bpf.c
+++ b/net/ipv4/tcp_bpf.c
@@ -198,6 +198,7 @@ static int tcp_bpf_recvmsg(struct sock *sk, struct msghdr *msg, size_t len,
 	if (unlikely(!psock))
 		return tcp_recvmsg(sk, msg, len, nonblock, flags, addr_len);
 	if (!skb_queue_empty(&sk->sk_receive_queue) &&
+	    !sk_psock_strparser_started(sk) &&
 	    sk_psock_queue_empty(psock)) {
 		sk_psock_put(sk, psock);
 		return tcp_recvmsg(sk, msg, len, nonblock, flags, addr_len);
@@ -214,9 +215,11 @@ static int tcp_bpf_recvmsg(struct sock *sk, struct msghdr *msg, size_t len,
 		if (data) {
 			if (!sk_psock_queue_empty(psock))
 				goto msg_bytes_ready;
-			release_sock(sk);
-			sk_psock_put(sk, psock);
-			return tcp_recvmsg(sk, msg, len, nonblock, flags, addr_len);
+			if (!sk_psock_strparser_started(sk)) {
+				release_sock(sk);
+				sk_psock_put(sk, psock);
+				return tcp_recvmsg(sk, msg, len, nonblock, flags, addr_len);
+			}
 		}
 		copied = -EAGAIN;
 	}
-- 
2.17.1