[PATCH iproute2] ss: fix fallback to procfs for raw sockets

Jonas reports that ss -awp does not display any RAW sockets
on a Knoppix 4.4 kernel.

sockdiag_send() diverts to tcpdiag_send() to try the older
netlink interface. tcpdiag_send() works for TCP and DCCP
but not other protocols. Instead of rejecting unsupported
protocols (and missing RAW and SCTP) match on supported ones.

Link: https://lore.kernel.org/netdev/20210815231738.7b42bad4@mmluhan/ (local)
Reported-and-tested-by: Jonas Bechtel <redacted>
Fixes: 41fe6c34de50 ("ss: Add inet raw sockets information gathering via netlink diag interface")
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
---
 misc/ss.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/misc/ss.c b/misc/ss.c
index 894ad40574f1..b39f63fe3b17 100644
--- a/misc/ss.c
+++ b/misc/ss.c

@@ -3404,13 +3404,13 @@ static int tcpdiag_send(int fd, int protocol, struct filter *f)
 	struct iovec iov[3];
 	int iovlen = 1;
 
-	if (protocol == IPPROTO_UDP || protocol == IPPROTO_MPTCP)
-		return -1;
-
 	if (protocol == IPPROTO_TCP)
 		req.nlh.nlmsg_type = TCPDIAG_GETSOCK;
-	else
+	else if (protocol == IPPROTO_DCCP)
 		req.nlh.nlmsg_type = DCCPDIAG_GETSOCK;
+	else
+		return -1;
+
 	if (show_mem) {
 		req.r.idiag_ext |= (1<<(INET_DIAG_MEMINFO-1));
 		req.r.idiag_ext |= (1<<(INET_DIAG_SKMEMINFO-1));

-- 
2.31.1