On 2024/12/10 04:44, Halil Pasic wrote: > On Mon, 9 Dec 2024 20:36:45 +0800 > Guangguan Wang <guangguan.wang@xxxxxxxxxxxxxxxxx> wrote: > >>> I believe we would like to have a v3 here. Also I'm not sure >>> checking on saddr is sufficient, but I didn't do my research on >>> that question yet. >>> >>> Regards, >>> Halil >> >> Did you mean to research whether the daddr should be checked too? > > Right! Or is it implied that if saddr is a ipv4 mapped ipv6 addr > then the daddr must be ipv4 mapped ipv6 addr as well? > > Regards, > Halil I did a test by iperf3: A server with IPV4 addr 11.213.5.33/24 and real IPV6 addr 2012::1/64. A client with IPV4 addr 11.213.5.5/24 and real IPV6 addr 2012::2/64. iperf3 fails to run when server listen on IPV6 addr and client connect to server using IPV4 mapped IPV6 addr. commands show below: server: smc_run iperf3 -s -6 -B 2012::1 client: smc_run iperf3 -t 10 -c 2012::1 -6 -B ::ffff:11.213.5.5 Failure happened due to the connect() function got the errno -EAFNOSUPPORT, I also located the kernel code where the -EAFNOSUPPORT is returned (https://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next.git/tree/net/ipv6/ip6_output.c#:~:text=err%20%3D%20%2DEAFNOSUPPORT%3B). The call stack is: ip6_dst_lookup_tail+1 ip6_dst_lookup_flow+55 tcp_v6_connect+743 __inet_stream_connect+181 inet_stream_connect+59 kernel_connect+109 smc_connect+239 __sys_connect+179 __x64_sys_connect+26 do_syscall_64+112 entry_SYSCALL_64_after_hwframe+118 The kernel code mentioned above restricts that when the saddr is ipv4 mapped ipv6 addr, the daddr should be either ipv4 mapped ipv6 addr or ipv6_addr_any(::). As far as I know, the ipv6_addr_any daddr is used to connect to a server listen on ipv6_addr_any(::) by loopback connection. Thus, based on the test and the code, I think it has the restrict that for SMC-Rv2 if saddr is a ipv4 mapped ipv6 addr then the daddr must be ipv4 mapped ipv6 addr as well. Thanks, Guangguan Wang
