Re: ss command not showing raw sockets? (regression)

On Tue, 17 Aug 2021 18:47:06 -0600
David Ahern [off-list ref] wrote with subject
"Re: ss command not showing raw sockets? (regression)":

On 8/17/21 3:37 PM, Jakub Kicinski wrote:

quoted

Ah, good point, strace will show it. 

/me goes off to look at the strace Jonas sent off list.

Well this is unexpected:

sendmsg(3, {msg_name={sa_family=AF_NETLINK, nl_pid=0,
nl_groups=00000000}, msg_namelen=12, msg_iov=[{iov_base={{len=76,
type=DCCPDIAG_GETSOCK, ... --->8----------------  

From: Jakub Kicinski <kuba@kernel.org>
Subject: ss: fix fallback to procfs for raw and sctp sockets

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.

Fixes: 41fe6c34de50 ("ss: Add inet raw sockets information
gathering via netlink diag interface") Signed-off-by: Jakub
Kicinski [off-list ref] ---
 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));
  

That looks correct to me.

Jonas: can you build iproute2 and test?

I've cloned branch main as instructed in https://wiki.linuxfoundation.org/networking/iproute2. Most recent commit is 9b7ea92b9e3f. After building, no socket was listed in table.

Then I [manually] applied the patch and rebuilt. The patched version works well, I do see the two sockets right now.

Command was in both cases misc/ss -awp