diff mbox series

[net-next,1/4] mptcp: propagate fastclose error

Message ID 20220930155934.404466-2-mathew.j.martineau@linux.intel.com (mailing list archive)
State Accepted
Commit 69800e516e968fa1cf9202b872dc86515eeeebe6
Delegated to: Netdev Maintainers
Headers show
Series mptcp: Fastclose edge cases and error handling | expand

Checks

Context Check Description
netdev/tree_selection success Clearly marked for net-next
netdev/fixes_present success Fixes tag not required for -next series
netdev/subject_prefix success Link
netdev/cover_letter success Series has a cover letter
netdev/patch_count success Link
netdev/header_inline success No static functions without inline keyword in header files
netdev/build_32bit success Errors and warnings before: 3 this patch: 3
netdev/cc_maintainers success CCed 8 of 8 maintainers
netdev/build_clang success Errors and warnings before: 5 this patch: 5
netdev/module_param success Was 0 now: 0
netdev/verify_signedoff success Signed-off-by tag matches author and committer
netdev/check_selftest success No net selftest shell script
netdev/verify_fixes success No Fixes tag
netdev/build_allmodconfig_warn success Errors and warnings before: 3 this patch: 3
netdev/checkpatch success total: 0 errors, 0 warnings, 0 checks, 96 lines checked
netdev/kdoc success Errors and warnings before: 0 this patch: 0
netdev/source_inline success Was 0 now: 0

Commit Message

Mat Martineau Sept. 30, 2022, 3:59 p.m. UTC 
From: Paolo Abeni <pabeni@redhat.com>

When an mptcp socket is closed due to an incoming FASTCLOSE
option, so specific sk_err is set and later syscall will
fail usually with EPIPE.

Align the current fastclose error handling with TCP reset,
properly setting the socket error according to the current
msk state and propagating such error.

Additionally sendmsg() is currently not handling properly
the sk_err, always returning EPIPE.

Reviewed-by: Matthieu Baerts <matthieu.baerts@tessares.net>
Reviewed-by: Mat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: Mat Martineau <mathew.j.martineau@linux.intel.com>
---
 net/mptcp/protocol.c | 47 +++++++++++++++++++++++++++++++++-----------
 1 file changed, 36 insertions(+), 11 deletions(-)
diff mbox series

Patch

diff --git a/net/mptcp/protocol.c b/net/mptcp/protocol.c
index 760404b15cd0..cad0346c9281 100644
--- a/net/mptcp/protocol.c
+++ b/net/mptcp/protocol.c
@@ -1707,7 +1707,7 @@  static int mptcp_sendmsg(struct sock *sk, struct msghdr *msg, size_t len)
 			goto out;
 		} else if (ret) {
 			release_sock(ssk);
-			goto out;
+			goto do_error;
 		}
 		release_sock(ssk);
 	}
@@ -1717,9 +1717,13 @@  static int mptcp_sendmsg(struct sock *sk, struct msghdr *msg, size_t len)
 	if ((1 << sk->sk_state) & ~(TCPF_ESTABLISHED | TCPF_CLOSE_WAIT)) {
 		ret = sk_stream_wait_connect(sk, &timeo);
 		if (ret)
-			goto out;
+			goto do_error;
 	}
 
+	ret = -EPIPE;
+	if (unlikely(sk->sk_err || (sk->sk_shutdown & SEND_SHUTDOWN)))
+		goto do_error;
+
 	pfrag = sk_page_frag(sk);
 
 	while (msg_data_left(msg)) {
@@ -1728,11 +1732,6 @@  static int mptcp_sendmsg(struct sock *sk, struct msghdr *msg, size_t len)
 		bool dfrag_collapsed;
 		size_t psize, offset;
 
-		if (sk->sk_err || (sk->sk_shutdown & SEND_SHUTDOWN)) {
-			ret = -EPIPE;
-			goto out;
-		}
-
 		/* reuse tail pfrag, if possible, or carve a new one from the
 		 * page allocator
 		 */
@@ -1764,7 +1763,7 @@  static int mptcp_sendmsg(struct sock *sk, struct msghdr *msg, size_t len)
 		if (copy_page_from_iter(dfrag->page, offset, psize,
 					&msg->msg_iter) != psize) {
 			ret = -EFAULT;
-			goto out;
+			goto do_error;
 		}
 
 		/* data successfully copied into the write queue */
@@ -1796,7 +1795,7 @@  static int mptcp_sendmsg(struct sock *sk, struct msghdr *msg, size_t len)
 		__mptcp_push_pending(sk, msg->msg_flags);
 		ret = sk_stream_wait_memory(sk, &timeo);
 		if (ret)
-			goto out;
+			goto do_error;
 	}
 
 	if (copied)
@@ -1804,7 +1803,14 @@  static int mptcp_sendmsg(struct sock *sk, struct msghdr *msg, size_t len)
 
 out:
 	release_sock(sk);
-	return copied ? : ret;
+	return copied;
+
+do_error:
+	if (copied)
+		goto out;
+
+	copied = sk_stream_error(sk, msg->msg_flags, ret);
+	goto out;
 }
 
 static int __mptcp_recvmsg_mskq(struct mptcp_sock *msk,
@@ -2441,12 +2447,31 @@  static void mptcp_check_fastclose(struct mptcp_sock *msk)
 		unlock_sock_fast(tcp_sk, slow);
 	}
 
+	/* Mirror the tcp_reset() error propagation */
+	switch (sk->sk_state) {
+	case TCP_SYN_SENT:
+		sk->sk_err = ECONNREFUSED;
+		break;
+	case TCP_CLOSE_WAIT:
+		sk->sk_err = EPIPE;
+		break;
+	case TCP_CLOSE:
+		return;
+	default:
+		sk->sk_err = ECONNRESET;
+	}
+
 	inet_sk_state_store(sk, TCP_CLOSE);
 	sk->sk_shutdown = SHUTDOWN_MASK;
 	smp_mb__before_atomic(); /* SHUTDOWN must be visible first */
 	set_bit(MPTCP_WORK_CLOSE_SUBFLOW, &msk->flags);
 
-	mptcp_close_wake_up(sk);
+	/* the calling mptcp_worker will properly destroy the socket */
+	if (sock_flag(sk, SOCK_DEAD))
+		return;
+
+	sk->sk_state_change(sk);
+	sk_error_report(sk);
 }
 
 static void __mptcp_retrans(struct sock *sk)