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[mptcp-next,3/3] mptcp: support IPV6_V6ONLY setsockopt

Message ID 20200624192448.20837-4-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 
Without this, Opensshd fails to open an ipv6 socket listening
socket:
  error: setsockopt IPV6_V6ONLY: Operation not supported
  error: Bind to port 22 on :: failed: Address already in use.

Opensshd opens an ipv4 and and ipv6 listening socket, but because
IPV6_V6ONLY setsockopt fails, the port number is already in use.

Signed-off-by: Florian Westphal <fw@strlen.de>
---
 net/mptcp/protocol.c | 30 ++++++++++++++++++++++++++++++
 1 file changed, 30 insertions(+)
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Patch

diff --git a/net/mptcp/protocol.c b/net/mptcp/protocol.c
index 469f651fbdff..db22929132ca 100644
--- a/net/mptcp/protocol.c
+++ b/net/mptcp/protocol.c
@@ -1632,6 +1632,33 @@  static int mptcp_setsockopt_sol_socket(struct mptcp_sock *msk, int optname,
 	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)
 {
@@ -1657,6 +1684,9 @@  static int mptcp_setsockopt(struct sock *sk, int level, int optname,
 		return tcp_setsockopt(ssock->sk, level, optname, optval,
 				      optlen);
 
+	if (level == SOL_IPV6)
+		return mptcp_setsockopt_v6(msk, optname, optval, optlen);
+
 	return -EOPNOTSUPP;
 }