1 files changed, 126 insertions, 6 deletions

diff --git a/net/mptcp/protocol.c b/net/mptcp/protocol.c
index 5e24e7cf7d70..294b03a0393a 100644
--- a/net/mptcp/protocol.c
+++ b/net/mptcp/protocol.c
@@ -17,6 +17,53 @@
 #include <net/mptcp.h>
 #include "protocol.h"
 
+#define MPTCP_SAME_STATE TCP_MAX_STATES
+
+/* If msk has an initial subflow socket, and the MP_CAPABLE handshake has not
+ * completed yet or has failed, return the subflow socket.
+ * Otherwise return NULL.
+ */
+static struct socket *__mptcp_nmpc_socket(const struct mptcp_sock *msk)
+{
+	if (!msk->subflow)
+		return NULL;
+
+	return msk->subflow;
+}
+
+static bool __mptcp_can_create_subflow(const struct mptcp_sock *msk)
+{
+	return ((struct sock *)msk)->sk_state == TCP_CLOSE;
+}
+
+static struct socket *__mptcp_socket_create(struct mptcp_sock *msk, int state)
+{
+	struct mptcp_subflow_context *subflow;
+	struct sock *sk = (struct sock *)msk;
+	struct socket *ssock;
+	int err;
+
+	ssock = __mptcp_nmpc_socket(msk);
+	if (ssock)
+		goto set_state;
+
+	if (!__mptcp_can_create_subflow(msk))
+		return ERR_PTR(-EINVAL);
+
+	err = mptcp_subflow_create_socket(sk, &ssock);
+	if (err)
+		return ERR_PTR(err);
+
+	msk->subflow = ssock;
+	subflow = mptcp_subflow_ctx(ssock->sk);
+	subflow->request_mptcp = 1;
+
+set_state:
+	if (state != MPTCP_SAME_STATE)
+		inet_sk_state_store(sk, state);
+	return ssock;
+}
+
 static int mptcp_sendmsg(struct sock *sk, struct msghdr *msg, size_t len)
 {
 	struct mptcp_sock *msk = mptcp_sk(sk);
@@ -48,12 +95,14 @@ static int mptcp_init_sock(struct sock *sk)
 static void mptcp_close(struct sock *sk, long timeout)
 {
 	struct mptcp_sock *msk = mptcp_sk(sk);
+	struct socket *ssock;
 
 	inet_sk_state_store(sk, TCP_CLOSE);
 
-	if (msk->subflow) {
-		pr_debug("subflow=%p", msk->subflow->sk);
-		sock_release(msk->subflow);
+	ssock = __mptcp_nmpc_socket(msk);
+	if (ssock) {
+		pr_debug("subflow=%p", mptcp_subflow_ctx(ssock->sk));
+		sock_release(ssock);
 	}
 
 	sock_orphan(sk);
@@ -67,7 +116,8 @@ static int mptcp_connect(struct sock *sk, struct sockaddr *saddr, int len)
 
 	saddr->sa_family = AF_INET;
 
-	pr_debug("msk=%p, subflow=%p", msk, msk->subflow->sk);
+	pr_debug("msk=%p, subflow=%p", msk,
+		 mptcp_subflow_ctx(msk->subflow->sk));
 
 	err = kernel_connect(msk->subflow, saddr, len, 0);
 
@@ -93,15 +143,79 @@ static struct proto mptcp_prot = {
 	.no_autobind	= true,
 };
 
+static int mptcp_bind(struct socket *sock, struct sockaddr *uaddr, int addr_len)
+{
+	struct mptcp_sock *msk = mptcp_sk(sock->sk);
+	struct socket *ssock;
+	int err = -ENOTSUPP;
+
+	if (uaddr->sa_family != AF_INET) // @@ allow only IPv4 for now
+		return err;
+
+	lock_sock(sock->sk);
+	ssock = __mptcp_socket_create(msk, MPTCP_SAME_STATE);
+	if (IS_ERR(ssock)) {
+		err = PTR_ERR(ssock);
+		goto unlock;
+	}
+
+	err = ssock->ops->bind(ssock, uaddr, addr_len);
+
+unlock:
+	release_sock(sock->sk);
+	return err;
+}
+
+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 socket *ssock;
+	int err;
+
+	lock_sock(sock->sk);
+	ssock = __mptcp_socket_create(msk, TCP_SYN_SENT);
+	if (IS_ERR(ssock)) {
+		err = PTR_ERR(ssock);
+		goto unlock;
+	}
+
+	err = ssock->ops->connect(ssock, uaddr, addr_len, flags);
+	inet_sk_state_store(sock->sk, inet_sk_state_load(ssock->sk));
+
+unlock:
+	release_sock(sock->sk);
+	return err;
+}
+
+static __poll_t mptcp_poll(struct file *file, struct socket *sock,
+			   struct poll_table_struct *wait)
+{
+	__poll_t mask = 0;
+
+	return mask;
+}
+
+static struct proto_ops mptcp_stream_ops;
+
 static struct inet_protosw mptcp_protosw = {
 	.type		= SOCK_STREAM,
 	.protocol	= IPPROTO_MPTCP,
 	.prot		= &mptcp_prot,
-	.ops		= &inet_stream_ops,
+	.ops		= &mptcp_stream_ops,
+	.flags		= INET_PROTOSW_ICSK,
 };
 
 void __init mptcp_init(void)
 {
+	mptcp_prot.h.hashinfo = tcp_prot.h.hashinfo;
+	mptcp_stream_ops = inet_stream_ops;
+	mptcp_stream_ops.bind = mptcp_bind;
+	mptcp_stream_ops.connect = mptcp_stream_connect;
+	mptcp_stream_ops.poll = mptcp_poll;
+
+	mptcp_subflow_init();
+
 	if (proto_register(&mptcp_prot, 1) != 0)
 		panic("Failed to register MPTCP proto.\n");
 
@@ -109,13 +223,14 @@ void __init mptcp_init(void)
 }
 
 #if IS_ENABLED(CONFIG_MPTCP_IPV6)
+static struct proto_ops mptcp_v6_stream_ops;
 static struct proto mptcp_v6_prot;
 
 static struct inet_protosw mptcp_v6_protosw = {
 	.type		= SOCK_STREAM,
 	.protocol	= IPPROTO_MPTCP,
 	.prot		= &mptcp_v6_prot,
-	.ops		= &inet6_stream_ops,
+	.ops		= &mptcp_v6_stream_ops,
 	.flags		= INET_PROTOSW_ICSK,
 };
 
@@ -133,6 +248,11 @@ int mptcpv6_init(void)
 	if (err)
 		return err;
 
+	mptcp_v6_stream_ops = inet6_stream_ops;
+	mptcp_v6_stream_ops.bind = mptcp_bind;
+	mptcp_v6_stream_ops.connect = mptcp_stream_connect;
+	mptcp_v6_stream_ops.poll = mptcp_poll;
+
 	err = inet6_register_protosw(&mptcp_v6_protosw);
 	if (err)
 		proto_unregister(&mptcp_v6_prot);