Function fill_addrinfo

freebsd/net/rtsock.c:620–699

* Fills in @info based on userland-provided @rtm message. * * Returns 0 on success. */

 * Returns 0 on success.
 */
static int
fill_addrinfo(struct rt_msghdr *rtm, int len, u_int fibnum, struct rt_addrinfo *info)
{
	int error;
	sa_family_t saf;

	rtm->rtm_pid = curproc->p_pid;
	info->rti_addrs = rtm->rtm_addrs;

	info->rti_mflags = rtm->rtm_inits;
	info->rti_rmx = &rtm->rtm_rmx;

	/*
	 * rt_xaddrs() performs s6_addr[2] := sin6_scope_id for AF_INET6
	 * link-local address because rtrequest requires addresses with
	 * embedded scope id.
	 */
	if (rt_xaddrs((caddr_t)(rtm + 1), len + (caddr_t)rtm, info))
		return (EINVAL);

	if (rtm->rtm_flags & RTF_RNH_LOCKED)
		return (EINVAL);
	info->rti_flags = rtm->rtm_flags;
	error = cleanup_xaddrs(info);
	if (error != 0)
		return (error);
	saf = info->rti_info[RTAX_DST]->sa_family;
	/*
	 * Verify that the caller has the appropriate privilege; RTM_GET
	 * is the only operation the non-superuser is allowed.
	 */
	if (rtm->rtm_type != RTM_GET) {
		error = priv_check(curthread, PRIV_NET_ROUTE);
		if (error != 0)
			return (error);
	}

	/*
	 * The given gateway address may be an interface address.
	 * For example, issuing a "route change" command on a route
	 * entry that was created from a tunnel, and the gateway
	 * address given is the local end point. In this case the 
	 * RTF_GATEWAY flag must be cleared or the destination will
	 * not be reachable even though there is no error message.
	 */
	if (info->rti_info[RTAX_GATEWAY] != NULL &&
	    info->rti_info[RTAX_GATEWAY]->sa_family != AF_LINK) {
		struct rt_addrinfo ginfo;
		struct sockaddr *gdst;
		struct sockaddr_storage ss;

		bzero(&ginfo, sizeof(ginfo));
		bzero(&ss, sizeof(ss));
		ss.ss_len = sizeof(ss);

		ginfo.rti_info[RTAX_GATEWAY] = (struct sockaddr *)&ss;
		gdst = info->rti_info[RTAX_GATEWAY];