hexdumps for incoming udp packets?

[onehalf3570]

Are they supposed to be there?
I have verbose-packets set to 2 and for tcp this is working ('hexdump of incoming packet' prints (

sslh/tcp-probe.c

Line 49 in 579baae

print_message(msg_packets, "hexdump of incoming packet:\n");

)), but for udp I don't see anything at all..

UDP itself works, although there is only one is_udp: true entry in the protocols section, so maybe the probing is just optimized out in this case.

UPD: apparently it gets optimized out, because if I add another UDP protocol entry, then the first one stops working (my regex isn't good enough yet ;)
but still, no hexdumps ;(

UPD2: I'm using

socat - UDP4-SENDTO:external_fqdn:external_port

to send test packets and I can see them in the internal server debug logs (when there is only one UDP protocol entry and everything gets forwarded there), so the test method is correct/working.

UPD3:
shouldn't it be somewhere around here?

sslh/udp-listener.c

Line 286 in 579baae

if (target == -1) {

I know that I can run tcpdump and get all that easily, but thought that it might be nice to have consistent behaviour for both tcp and udp ;)

[onehalf3570]

Basically this seems to do the job:

diff --git a/udp-listener.c b/udp-listener.c
index de99f6e..698721b 100644
--- a/udp-listener.c
+++ b/udp-listener.c
@@ -284,6 +284,9 @@ struct connection* udp_c2s_forward(int sockfd, struct loop_info* fd_info)
                   len, target, sprintaddr(addr_str, sizeof(addr_str), &addrinfo));
 
     if (target == -1) {
+       print_message(msg_packets, "hexdump of incoming UDP packet:\n");
+       hexdump(msg_packets, data, len);
+
         res = probe_buffer(data, (int)len, udp_protocols, udp_protocols_len, &proto);
         /* First version: if we can't work out the protocol from the first
          * packet, drop it. Conceivably, we could store several packets to

(Should I create a pull request for this? I think this is useful..)

Funny thing is that despite having libwrap0-dev installed and compiled in:

cc -Wall -O2 -DLIBPCRE -g    -o sslh-ev processes.o udp-listener.o sslh-ev.o hash.o tcp-listener.o libsslh.a -lm -lpcre2-8  -lwrap -lconfig -lev

..I still get this message during startup:

sslh-ev[165119]: name: "timeout"; host: "localhost"; port: "daytime": WARNING: `service' specified but libwrap not compiled in. Ignoring setting.

[yrutschle]

Yes, it's surprising I didn't need hexdump for UDP debugging... Thanks for prodding me, I did it slightly differently in probe_buffer() instead to avoid code duplication.

About the libwrap issue: does it say you have it when you sslh -V ? The warning uses the HAVE_LIBWRAP which is defined in config.h, which I guess could somehow end up out of sync with the Makefile, although it shouldn't...

[onehalf3570]

Yes, it's surprising I didn't need hexdump for UDP debugging... Thanks for prodding me, I did it slightly differently in probe_buffer() instead to avoid code duplication.

About the libwrap issue: does it say you have it when you sslh -V ? The warning uses the HAVE_LIBWRAP which is defined in config.h, which I guess could somehow end up out of sync with the Makefile, although it shouldn't...

Thanks for the fix!
Yes, indeed sslh -V didn't show libwrap 🤔 Anyway, doing git clean -xfd and then configure again solved this. Thanks!