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[mptcp-next,2/3] mptcp: add REUSEADDR/REUSEPORT support

Message ID 20200624192448.20837-3-fw@strlen.de
State Accepted, archived
Delegated to: Matthieu Baerts
Headers show
Series setsockopt: allow reuseport and ip6only | expand

Commit Message

Florian Westphal June 24, 2020, 7:24 p.m. UTC
This will e.g. make 'sshd restart' work when MPTCP is used, as we will
now set this option on the listener socket instead of only the mptcp
socket (where it has no effect).

We still need to copy the setting to the master socket so that a
subsequent getsockopt() returns the expected value.

Reported-by: Christoph Paasch <cpaasch@apple.com>
Suggested-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: Florian Westphal <fw@strlen.de>
---
 net/mptcp/protocol.c | 34 +++++++++++++++++++++++++++++++++-
 1 file changed, 33 insertions(+), 1 deletion(-)
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Patch

diff --git a/net/mptcp/protocol.c b/net/mptcp/protocol.c
index f1ecdc7084ca..469f651fbdff 100644
--- a/net/mptcp/protocol.c
+++ b/net/mptcp/protocol.c
@@ -1601,6 +1601,37 @@  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(struct sock *sk, int level, int optname,
 			    char __user *optval, unsigned int optlen)
 {
@@ -1610,7 +1641,8 @@  static int mptcp_setsockopt(struct sock *sk, int level, int optname,
 	pr_debug("msk=%p", msk);
 
 	if (level == SOL_SOCKET)
-		return sock_setsockopt(sk->sk_socket, level, optname, optval, optlen);
+		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