s6fromaddr
if (s6fromaddr(ss2sin6(&sp->to), buf,
if (s6fromaddr(&sin6, NULL, DHCP6_SERVER_PORT_STR, 1) == -1)
if (s6fromaddr(&sin6, DHCP6_ADDR_RELAYSERVER, NULL, 0) == -1)
if (s6fromaddr(&sin6, NULL, DHCP6_SERVER_PORT_STR, 1) == -1)
int s6fromaddr(struct sockaddr_in6 *, const char *, const char *, int);