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mptcp: factor out mptcp_connect()

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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: d98a82a6af ("mptcp: handle defer connect in mptcp_sendmsg")
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>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
This commit is contained in:
Paolo Abeni 2022-10-21 15:58:55 -07:00 committed by Jakub Kicinski
parent e72e403263
commit 54f1944ed6
2 changed files with 73 additions and 67 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

136
net/mptcp/protocol.c
View File

@ -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 @@ unlock:
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)

4
net/mptcp/protocol.h
View File

@ -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;