Hi there!
with the current master and the 5.10 kernel, I have some trouble with large outgoing packets. It seems packets larger than 1496 bytes originating from the CPU are not sent out. Switched packets between outside ports are not affected, switching seems to work fine, at least with the bugfixes of PR #4535 included.
These outgoing packets are visible in tcpdump -i switch.vlanid but don't actually seem to go to wire. Here are two dumps, one from the switch:
root@OpenWrt:~# tcpdump -i switch.100 -n
[ 3159.589614] device switch.100 entered promiscuous mode
[ 3159.595488] device switch entered promiscuous mode
tcpdump: verbose output suppressed, use -v or -vv for full protocol decode
listening on switch.100, link-type EN10MB (Ethernet), capture size 262144 bytes
22:51:17.620667 IP 10.1.1.100 > 10.1.0.102: ICMP echo request, id 69, seq 1, length 1476
22:51:17.621103 IP 10.1.0.102 > 10.1.1.100: ICMP echo reply, id 69, seq 1, length 1476
22:51:18.621795 IP 10.1.1.100 > 10.1.0.102: ICMP echo request, id 69, seq 2, length 1476
22:51:18.622173 IP 10.1.0.102 > 10.1.1.100: ICMP echo reply, id 69, seq 2, length 1476
22:51:19.622698 IP 10.1.1.100 > 10.1.0.102: ICMP echo request, id 69, seq 3, length 1476
22:51:19.623085 IP 10.1.0.102 > 10.1.1.100: ICMP echo reply, id 69, seq 3, length 1476
22:51:24.628064 ARP, Request who-has 10.1.0.1 tell 10.1.0.102, length 28
22:51:24.628624 ARP, Reply 10.1.0.1 is-at 4a:17:f1:89:2f:c2, length 42
22:51:26.775001 IP 10.1.1.100 > 10.1.0.102: ICMP echo request, id 70, seq 1, length 1477
22:51:26.775437 IP 10.1.0.102 > 10.1.1.100: ICMP echo reply, id 70, seq 1, length 1477
22:51:27.786844 IP 10.1.1.100 > 10.1.0.102: ICMP echo request, id 70, seq 2, length 1477
22:51:27.787219 IP 10.1.0.102 > 10.1.1.100: ICMP echo reply, id 70, seq 2, length 1477
22:51:28.810738 IP 10.1.1.100 > 10.1.0.102: ICMP echo request, id 70, seq 3, length 1477
22:51:28.811113 IP 10.1.0.102 > 10.1.1.100: ICMP echo reply, id 70, seq 3, length 1477
and from the router (10.1.0.1) in-between the switch and my desktop:
root@router:~# tcpdump -i eth0.100 host 10.1.0.102 -n
tcpdump: verbose output suppressed, use -v or -vv for full protocol decode
listening on eth0.100, link-type EN10MB (Ethernet), capture size 262144 bytes
00:51:17.616106 IP 10.1.1.100 > 10.1.0.102: ICMP echo request, id 69, seq 1, length 1476
00:51:17.617416 IP 10.1.0.102 > 10.1.1.100: ICMP echo reply, id 69, seq 1, length 1476
00:51:18.617245 IP 10.1.1.100 > 10.1.0.102: ICMP echo request, id 69, seq 2, length 1476
00:51:18.618372 IP 10.1.0.102 > 10.1.1.100: ICMP echo reply, id 69, seq 2, length 1476
00:51:19.618132 IP 10.1.1.100 > 10.1.0.102: ICMP echo request, id 69, seq 3, length 1476
00:51:19.619246 IP 10.1.0.102 > 10.1.1.100: ICMP echo reply, id 69, seq 3, length 1476
00:51:24.624110 ARP, Request who-has 10.1.0.1 tell 10.1.0.102, length 46
00:51:24.624271 ARP, Reply 10.1.0.1 is-at 4a:17:f1:89:2f:c2, length 28
00:51:26.770443 IP 10.1.1.100 > 10.1.0.102: ICMP echo request, id 70, seq 1, length 1477
00:51:27.782251 IP 10.1.1.100 > 10.1.0.102: ICMP echo request, id 70, seq 2, length 1477
00:51:28.806175 IP 10.1.1.100 > 10.1.0.102: ICMP echo request, id 70, seq 3, length 1477
(Forgive the different time-zones)
This seems to be already present before the recently merged PR #4535, I just tested a build of commit f887c93.
Any ideas? Is this another quirk of the DGS-1210 bootloader initialization?