MFC:
sys/sys/socket.h ver. 1.93

lib/libc/net/rthdr.c ver. 1.9

date: 2007/04/19 15:48:16; author: mtm; state: Exp; lines: +4 -2
Make inet6_rth_* family of functions more compliant with RFC3542:

1. CMSG_NXTHDR(mhdr, cmsg) is supposed to dereference cmsg and return the next header in the chain. If cmsg is NULL it should return the first header, behaving essentially like CMSG_FIRSTHDR().
2. inet6_rth_(space|init|add) should do basic checking on their input to verify that the number of headers (segments) is between 0 and 127 inclusive.