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Date: Fri, 21 Oct 2022 15:58:55 -0700
From: Mat Martineau <mathew.j.martineau@...ux.intel.com>
To: netdev@...r.kernel.org
Cc: Paolo Abeni <pabeni@...hat.com>, davem@...emloft.net,
kuba@...nel.org, edumazet@...gle.com, dmytro@...tyi.net,
benjamin.hesmans@...sares.net, matthieu.baerts@...sares.net,
mptcp@...ts.linux.dev,
Mat Martineau <mathew.j.martineau@...ux.intel.com>
Subject: [PATCH net 2/3] mptcp: factor out mptcp_connect()
From: Paolo Abeni <pabeni@...hat.com>
The current MPTCP connect implementation duplicates a bit of inet
code and does not use nor provide a struct proto->connect callback,
which in turn will not fit the upcoming fastopen implementation.
Refactor such implementation to use the common helper, moving the
MPTCP-specific bits into mptcp_connect(). Additionally, avoid an
indirect call to the subflow connect callback.
Note that the fastopen call-path invokes mptcp_connect() while already
holding the subflow socket lock. Explicitly keep track of such path
via a new MPTCP-level flag and handle the locking accordingly.
Additionally, track the connect flags in a new msk field to allow
propagating them to the subflow inet_stream_connect call.
Fixes: d98a82a6afc7 ("mptcp: handle defer connect in mptcp_sendmsg")
Reviewed-by: Mat Martineau <mathew.j.martineau@...ux.intel.com>
Signed-off-by: Paolo Abeni <pabeni@...hat.com>
Signed-off-by: Mat Martineau <mathew.j.martineau@...ux.intel.com>
---
net/mptcp/protocol.c | 136 ++++++++++++++++++++++---------------------
net/mptcp/protocol.h | 4 +-
2 files changed, 73 insertions(+), 67 deletions(-)
diff --git a/net/mptcp/protocol.c b/net/mptcp/protocol.c
index e33f9caf409d..f2930699c6d3 100644
--- a/net/mptcp/protocol.c
+++ b/net/mptcp/protocol.c
@@ -1698,7 +1698,10 @@ static int mptcp_sendmsg(struct sock *sk, struct msghdr *msg, size_t len)
lock_sock(ssk);
+ msk->connect_flags = (msg->msg_flags & MSG_DONTWAIT) ? O_NONBLOCK : 0;
+ msk->is_sendmsg = 1;
ret = tcp_sendmsg_fastopen(ssk, msg, &copied_syn, len, NULL);
+ msk->is_sendmsg = 0;
copied += copied_syn;
if (ret == -EINPROGRESS && copied_syn > 0) {
/* reflect the new state on the MPTCP socket */
@@ -3507,10 +3510,73 @@ static int mptcp_ioctl(struct sock *sk, int cmd, unsigned long arg)
return put_user(answ, (int __user *)arg);
}
+static void mptcp_subflow_early_fallback(struct mptcp_sock *msk,
+ struct mptcp_subflow_context *subflow)
+{
+ subflow->request_mptcp = 0;
+ __mptcp_do_fallback(msk);
+}
+
+static int mptcp_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len)
+{
+ struct mptcp_subflow_context *subflow;
+ struct mptcp_sock *msk = mptcp_sk(sk);
+ struct socket *ssock;
+ int err = -EINVAL;
+
+ ssock = __mptcp_nmpc_socket(msk);
+ if (!ssock)
+ return -EINVAL;
+
+ mptcp_token_destroy(msk);
+ inet_sk_state_store(sk, TCP_SYN_SENT);
+ subflow = mptcp_subflow_ctx(ssock->sk);
+#ifdef CONFIG_TCP_MD5SIG
+ /* no MPTCP if MD5SIG is enabled on this socket or we may run out of
+ * TCP option space.
+ */
+ if (rcu_access_pointer(tcp_sk(ssock->sk)->md5sig_info))
+ mptcp_subflow_early_fallback(msk, subflow);
+#endif
+ if (subflow->request_mptcp && mptcp_token_new_connect(ssock->sk)) {
+ MPTCP_INC_STATS(sock_net(ssock->sk), MPTCP_MIB_TOKENFALLBACKINIT);
+ mptcp_subflow_early_fallback(msk, subflow);
+ }
+ if (likely(!__mptcp_check_fallback(msk)))
+ MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_MPCAPABLEACTIVE);
+
+ /* if reaching here via the fastopen/sendmsg path, the caller already
+ * acquired the subflow socket lock, too.
+ */
+ if (msk->is_sendmsg)
+ err = __inet_stream_connect(ssock, uaddr, addr_len, msk->connect_flags, 1);
+ else
+ err = inet_stream_connect(ssock, uaddr, addr_len, msk->connect_flags);
+ inet_sk(sk)->defer_connect = inet_sk(ssock->sk)->defer_connect;
+
+ /* on successful connect, the msk state will be moved to established by
+ * subflow_finish_connect()
+ */
+ if (unlikely(err && err != -EINPROGRESS)) {
+ inet_sk_state_store(sk, inet_sk_state_load(ssock->sk));
+ return err;
+ }
+
+ mptcp_copy_inaddrs(sk, ssock->sk);
+
+ /* unblocking connect, mptcp-level inet_stream_connect will error out
+ * without changing the socket state, update it here.
+ */
+ if (err == -EINPROGRESS)
+ sk->sk_socket->state = ssock->state;
+ return err;
+}
+
static struct proto mptcp_prot = {
.name = "MPTCP",
.owner = THIS_MODULE,
.init = mptcp_init_sock,
+ .connect = mptcp_connect,
.disconnect = mptcp_disconnect,
.close = mptcp_close,
.accept = mptcp_accept,
@@ -3562,78 +3628,16 @@ static int mptcp_bind(struct socket *sock, struct sockaddr *uaddr, int addr_len)
return err;
}
-static void mptcp_subflow_early_fallback(struct mptcp_sock *msk,
- struct mptcp_subflow_context *subflow)
-{
- subflow->request_mptcp = 0;
- __mptcp_do_fallback(msk);
-}
-
static int mptcp_stream_connect(struct socket *sock, struct sockaddr *uaddr,
int addr_len, int flags)
{
- struct mptcp_sock *msk = mptcp_sk(sock->sk);
- struct mptcp_subflow_context *subflow;
- struct socket *ssock;
- int err = -EINVAL;
+ int ret;
lock_sock(sock->sk);
- if (uaddr) {
- if (addr_len < sizeof(uaddr->sa_family))
- goto unlock;
-
- if (uaddr->sa_family == AF_UNSPEC) {
- err = mptcp_disconnect(sock->sk, flags);
- sock->state = err ? SS_DISCONNECTING : SS_UNCONNECTED;
- goto unlock;
- }
- }
-
- if (sock->state != SS_UNCONNECTED && msk->subflow) {
- /* pending connection or invalid state, let existing subflow
- * cope with that
- */
- ssock = msk->subflow;
- goto do_connect;
- }
-
- ssock = __mptcp_nmpc_socket(msk);
- if (!ssock)
- goto unlock;
-
- mptcp_token_destroy(msk);
- inet_sk_state_store(sock->sk, TCP_SYN_SENT);
- subflow = mptcp_subflow_ctx(ssock->sk);
-#ifdef CONFIG_TCP_MD5SIG
- /* no MPTCP if MD5SIG is enabled on this socket or we may run out of
- * TCP option space.
- */
- if (rcu_access_pointer(tcp_sk(ssock->sk)->md5sig_info))
- mptcp_subflow_early_fallback(msk, subflow);
-#endif
- if (subflow->request_mptcp && mptcp_token_new_connect(ssock->sk)) {
- MPTCP_INC_STATS(sock_net(ssock->sk), MPTCP_MIB_TOKENFALLBACKINIT);
- mptcp_subflow_early_fallback(msk, subflow);
- }
- if (likely(!__mptcp_check_fallback(msk)))
- MPTCP_INC_STATS(sock_net(sock->sk), MPTCP_MIB_MPCAPABLEACTIVE);
-
-do_connect:
- err = ssock->ops->connect(ssock, uaddr, addr_len, flags);
- inet_sk(sock->sk)->defer_connect = inet_sk(ssock->sk)->defer_connect;
- sock->state = ssock->state;
-
- /* on successful connect, the msk state will be moved to established by
- * subflow_finish_connect()
- */
- if (!err || err == -EINPROGRESS)
- mptcp_copy_inaddrs(sock->sk, ssock->sk);
- else
- inet_sk_state_store(sock->sk, inet_sk_state_load(ssock->sk));
-
-unlock:
+ mptcp_sk(sock->sk)->connect_flags = flags;
+ ret = __inet_stream_connect(sock, uaddr, addr_len, flags, 0);
release_sock(sock->sk);
- return err;
+ return ret;
}
static int mptcp_listen(struct socket *sock, int backlog)
diff --git a/net/mptcp/protocol.h b/net/mptcp/protocol.h
index be19592441df..6a09ab99a12d 100644
--- a/net/mptcp/protocol.h
+++ b/net/mptcp/protocol.h
@@ -285,7 +285,9 @@ struct mptcp_sock {
u8 mpc_endpoint_id;
u8 recvmsg_inq:1,
cork:1,
- nodelay:1;
+ nodelay:1,
+ is_sendmsg:1;
+ int connect_flags;
struct work_struct work;
struct sk_buff *ooo_last_skb;
struct rb_root out_of_order_queue;
--
2.38.1
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