tcp: update error counter when dropping a packet due to bad source

[glebius]

Summary

Use the same counter that ip_input()/ip6_input() use for bad destination
address. For IPv6 this is already heavily abused ip6s_badscope, which
needs to be split into several separate error counters.

[tuexen]

sys/netinet/tcp_input.c

678

Why do you keep the /* XXX */ in one case, but not in the other. I suggest to be consistent.

[markj]

sys/netinet/tcp_input.c

678

For v4, badaddr seems like a reasonable counter. Here, the use of badscope is overloaded, I believe the XXX comment indicates that this is not the right counter. However, it's better than not counting at all.

[glebius]

sys/netinet/tcp_input.c

678

Yes, exactly what Mark said. :)