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/
Reported-and-tested-by: Jonas Bechtel <post@jbechtel.de>
Fixes: 41fe6c34de50 ("ss: Add inet raw sockets information gathering via netlink diag interface")
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Stephen Hemminger <stephen@networkplumber.org>

diff --git a/misc/ss.c b/misc/ss.c
index 894ad40574f1058a9fa0b8519d29b154bf228d7e..b39f63fe3b17b390ae5fa56438708656f7a334b9 100644 (file)
--- 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));