Under RSS, assign a TCP flow's inp_flowid anyway.

[cc]

Summary

This brings some benefit of a tcp flow identification for some kernel
modules, such as siftr.

Test Plan

Tested in an Emulab testbed.

before this change:
cc@s1:~ % netstat -nRp tcp
Active Internet connections
Proto Recv-Q Send-Q Local Address Foreign Address flowid ftype
tcp6 28 0 fd00::2.41352 fd00::3.5001 00000000 0
tcp6 28 0 fd00::2.10845 fd00::3.5001 00000000 0
tcp6 28 0 fd00::2.28532 fd00::3.5001 00000000 0
tcp6 28 0 fd00::2.34124 fd00::3.5001 00000000 0
tcp4 0 0 127.0.0.1.16505 127.0.0.1.57268 00000000 0
tcp4 0 0 127.0.0.1.57268 127.0.0.1.16505 00000000 0
tcp4 0 0 127.0.0.1.16505 127.0.0.1.37918 00000000 0
tcp4 0 0 127.0.0.1.37918 127.0.0.1.16505 00000000 0

after this change:
cc@s1:~ % netstat -nRp tcp
Active Internet connections
Proto Recv-Q Send-Q Local Address Foreign Address flowid ftype
tcp6 28 0 fd00::2.43004 fd00::3.5001 8458ef94 132
tcp6 28 0 fd00::2.59450 fd00::3.5001 f96e24cf 132
tcp6 28 0 fd00::2.25706 fd00::3.5001 70119d2f 132
tcp6 28 0 fd00::2.27760 fd00::3.5001 8a1ed781 132
tcp4 0 0 127.0.0.1.16505 127.0.0.1.30417 e34c3361 130
tcp4 0 0 127.0.0.1.30417 127.0.0.1.16505 58b6e0bb 130
tcp4 0 0 127.0.0.1.16505 127.0.0.1.18519 c47bf08d 130
tcp4 0 0 127.0.0.1.18519 127.0.0.1.16505 9b5a6416 130

[tuexen]

sys/netinet/tcp_input.c

948

Would it make sense to organize the code above and below like:

if ((inp->inp_flowtype == M_HASHTYPE_NONE) &&
    !SOLISTENING(inp->inp_socket)) {
        if (M_HASHTYPE_GET(m) != M_HASHTYPE_NONE) {
                inp->inp_flowid = m->m_pkthdr.flowid;
		inp->inp_flowtype = M_HASHTYPE_GET(m);
#ifdef RSS
	} else {
                /* assign flowid by software RSS hash */
                ...
#endif
        }
}

[cc]

sys/netinet/tcp_input.c

948

Good idea. Will change. Thanks.

[cc]

cleanup change and fix a bug in this change

[tuexen]

sys/netinet/tcp_input.c

949

Why not do

#ifdef RSS
       } else {
...
#endif
       }

[cc]

sys/netinet/tcp_input.c

949

I see what you mean now. I will clean it up. Thanks.

[cc]

further cleanup