Commit bdd2ed27 authored by David S. Miller's avatar David S. Miller
Browse files

Merge branch 'mptcp-add-REUSEADDR-REUSEPORT-V6ONLY-setsockopt-support' 



Florian Westphal says:

====================
mptcp: add REUSEADDR/REUSEPORT/V6ONLY setsockopt support

restarting an mptcp-patched sshd yields following error:

  sshd: error: Bind to port 22 on 0.0.0.0 failed: Address already in use.
  sshd: error: setsockopt IPV6_V6ONLY: Operation not supported
  sshd: error: Bind to port 22 on :: failed: Address already in use.
  sshd: fatal: Cannot bind any address.

This series adds support for the needed setsockopts:

First patch skips the generic SOL_SOCKET handler for MPTCP:
in mptcp case, the setsockopt needs to alter the tcp socket, not the mptcp
parent socket.

Second patch adds minimal SOL_SOCKET support: REUSEPORT and REUSEADDR.
Rest is still handled by the generic SOL_SOCKET code.

Last patch adds IPV6ONLY support.  This makes ipv6 work for openssh:
It creates two listening sockets, before this patch, binding the ipv6
socket will fail because the port is already bound by the ipv4 one.
====================

Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parents f551e2fd c9b95a13

net/mptcp/protocol.c

+64 −0
Original line number Diff line number Diff line
@@ -1601,6 +1601,64 @@ static void mptcp_destroy(struct sock *sk) 
	sk_sockets_allocated_dec(sk);

}



static int mptcp_setsockopt_sol_socket(struct mptcp_sock *msk, int optname,

				       char __user *optval, unsigned int optlen)

{

	struct sock *sk = (struct sock *)msk;

	struct socket *ssock;

	int ret;



	switch (optname) {

	case SO_REUSEPORT:

	case SO_REUSEADDR:

		lock_sock(sk);

		ssock = __mptcp_nmpc_socket(msk);

		if (!ssock) {

			release_sock(sk);

			return -EINVAL;

		}



		ret = sock_setsockopt(ssock, SOL_SOCKET, optname, optval, optlen);

		if (ret == 0) {

			if (optname == SO_REUSEPORT)

				sk->sk_reuseport = ssock->sk->sk_reuseport;

			else if (optname == SO_REUSEADDR)

				sk->sk_reuse = ssock->sk->sk_reuse;

		}

		release_sock(sk);

		return ret;

	}



	return sock_setsockopt(sk->sk_socket, SOL_SOCKET, optname, optval, optlen);

}



static int mptcp_setsockopt_v6(struct mptcp_sock *msk, int optname,

			       char __user *optval, unsigned int optlen)

{

	struct sock *sk = (struct sock *)msk;

	int ret = -EOPNOTSUPP;

	struct socket *ssock;



	switch (optname) {

	case IPV6_V6ONLY:

		lock_sock(sk);

		ssock = __mptcp_nmpc_socket(msk);

		if (!ssock) {

			release_sock(sk);

			return -EINVAL;

		}



		ret = tcp_setsockopt(ssock->sk, SOL_IPV6, optname, optval, optlen);

		if (ret == 0)

			sk->sk_ipv6only = ssock->sk->sk_ipv6only;



		release_sock(sk);

		break;

	}



	return ret;

}



static int mptcp_setsockopt(struct sock *sk, int level, int optname,

			    char __user *optval, unsigned int optlen)

{
@@ -1609,6 +1667,9 @@ static int mptcp_setsockopt(struct sock *sk, int level, int optname, 


	pr_debug("msk=%p", msk);



	if (level == SOL_SOCKET)

		return mptcp_setsockopt_sol_socket(msk, optname, optval, optlen);



	/* @@ the meaning of setsockopt() when the socket is connected and

	 * there are multiple subflows is not yet defined. It is up to the

	 * MPTCP-level socket to configure the subflows until the subflow
@@ -1621,6 +1682,9 @@ static int mptcp_setsockopt(struct sock *sk, int level, int optname, 
	if (ssk)

		return tcp_setsockopt(ssk, level, optname, optval, optlen);



	if (level == SOL_IPV6)

		return mptcp_setsockopt_v6(msk, optname, optval, optlen);



	return -EOPNOTSUPP;

}

net/socket.c

+12 −1
Original line number Diff line number Diff line
@@ -2080,6 +2080,17 @@ SYSCALL_DEFINE4(recv, int, fd, void __user *, ubuf, size_t, size, 
	return __sys_recvfrom(fd, ubuf, size, flags, NULL, NULL);

}



static bool sock_use_custom_sol_socket(const struct socket *sock)

{

	const struct sock *sk = sock->sk;



	/* Use sock->ops->setsockopt() for MPTCP */

	return IS_ENABLED(CONFIG_MPTCP) &&

	       sk->sk_protocol == IPPROTO_MPTCP &&

	       sk->sk_type == SOCK_STREAM &&

	       (sk->sk_family == AF_INET || sk->sk_family == AF_INET6);

}



/*

 *	Set a socket option. Because we don't know the option lengths we have

 *	to pass the user mode parameter for the protocols to sort out.
@@ -2118,7 +2129,7 @@ static int __sys_setsockopt(int fd, int level, int optname, 
			optval = (char __user __force *)kernel_optval;

		}



		if (level == SOL_SOCKET)

		if (level == SOL_SOCKET && !sock_use_custom_sol_socket(sock))

			err =

			    sock_setsockopt(sock, level, optname, optval,

					    optlen);