Hi Daniel, On Thu, Mar 07, 2024 at 02:34:38PM +0100, Daniel Mack wrote: > On 3/6/24 19:17, Pablo Neira Ayuso wrote: [...] > > I guess you are running a kernel with > > > > commit 0ae8e4cca78781401b17721bfb72718fdf7b4912 > > Author: Pablo Neira Ayuso <pablo@xxxxxxxxxxxxx> > > Date: Thu Dec 14 11:50:12 2023 +0100 > > > > netfilter: nf_tables: set transport offset from mac header for netdev/egress > > > > so this is a different bug? > > Interesting, I did in fact run a 6.4 production kernel when I tried > this, and that didn't have that patch applied. Sorry for that oversight. > > On 6.7, what I see is different but still broken: I'm here with 6.8.0-rc6+: > This rules does the right thing and patches the source MAC correctly: > > table netdev dummy { > chain egress { > type filter hook egress device dummy priority 0; > ether saddr set 1:2:3:4:5:6 dup to eth0 > } > } > > Whereas trying to patch the IP source addr leads to no packets being > forwarded at all anymore: My setup: # ip link set up dev dummy # ip a a 10.141.10.1/24 dev dummy # ip ro del local 10.141.10.1 dev dummy table local proto kernel scope host src 10.141.10.1 testing with ping to 10.141.10.1 I need to remove the local route, otherwise packets go through loopback interface. > table netdev dummy { > chain egress { > type filter hook egress device dummy priority 0; > ip saddr set 1.1.1.1 dup to eth0 > } > } 1) tcpdump in dummy: 17:14:42.939483 f2:20:1a:4c:c4:a1 > f2:20:1a:4c:c4:a1, ethertype IPv4 (0x0800), length 98: 1.1.1.1 > 10.141.10.1: ICMP echo request, id 46403, seq 1, length 64 2) tcpdump in eth0: 17:15:21.006853 f2:20:1a:4c:c4:a1 > f2:20:1a:4c:c4:a1, ethertype IPv4 (0x0800), length 98: 1.1.1.1 > 10.141.10.1: ICMP echo request, id 1087, seq 1, length 64 > Interestingly, ether type filtering is also broken now, the following > also doesn't match any packets: > > table netdev dummy { > chain egress { > type filter hook egress device dummy priority 0; > ether type ip dup to eth0 > } > } 1) tcpdump in dummy 17:18:13.921128 f2:20:1a:4c:c4:a1 > f2:20:1a:4c:c4:a1, ethertype IPv4 (0x0800), length 98: 10.141.10.1 > 10.141.10.1: ICMP echo request, id 137, seq 1, length 64 2) tcpdump in eth0: 17:19:00.398882 f2:20:1a:4c:c4:a1 > f2:20:1a:4c:c4:a1, ethertype IPv4 (0x0800), length 98: 10.141.10.1 > 10.141.10.1: ICMP echo request, id 21186, seq 1, length 64 > I browsed through the patches since 6.7 and couldn't find anything that > is related. Did I miss anything? I tried again this first example you posted: table netdev dummy { chain egress { type filter hook egress device "dummy" priority 0; ether type ip ether saddr set 01:02:03:04:05:06 ip saddr set 1.1.1.1 dup to "eth0" } } tcpdump dummy: 17:22:08.390312 01:02:03:04:05:06 > f2:20:1a:4c:c4:a1, ethertype IPv4 (0x0800), length 98: 1.1.1.1 > 10.141.10.1: ICMP echo request, id 47168, seq 1, length 64 tcpdump enps25: 17:20:28.298524 01:02:03:04:05:06 > f2:20:1a:4c:c4:a1, ethertype IPv4 (0x0800), length 98: 1.1.1.1 > 10.141.10.1: ICMP echo request, id 15435, seq 1, length 64 Maybe my setup is different?