Function update_rtm_from_rc

freebsd/net/rtsock.c:889–965

* Update sockaddrs, flags, etc in @prtm based on @rc data. * rtm can be reallocated. * * Returns 0 on success, along with pointer to (potentially reallocated) * rtm. * */

 *
 */
static int
update_rtm_from_rc(struct rt_addrinfo *info, struct rt_msghdr **prtm,
    int alloc_len, struct rib_cmd_info *rc, struct nhop_object *nh)
{
	struct walkarg w;
	union sockaddr_union saun;
	struct rt_msghdr *rtm, *orig_rtm = NULL;
	struct ifnet *ifp;
	int error, len;

	rtm = *prtm;
	union sockaddr_union sa_dst, sa_mask;
	int family = info->rti_info[RTAX_DST]->sa_family;
	init_sockaddrs_family(family, &sa_dst.sa, &sa_mask.sa);
	export_rtaddrs(rc->rc_rt, &sa_dst.sa, &sa_mask.sa);

	info->rti_info[RTAX_DST] = &sa_dst.sa;
	info->rti_info[RTAX_NETMASK] = rt_is_host(rc->rc_rt) ? NULL : &sa_mask.sa;
	info->rti_info[RTAX_GATEWAY] = &nh->gw_sa;
	info->rti_info[RTAX_GENMASK] = 0;
	ifp = nh->nh_ifp;
	if (rtm->rtm_addrs & (RTA_IFP | RTA_IFA)) {
		if (ifp) {
			info->rti_info[RTAX_IFP] =
			    ifp->if_addr->ifa_addr;
			error = rtm_get_jailed(info, ifp, nh,
			    &saun, curthread->td_ucred);
			if (error != 0)
				return (error);
			if (ifp->if_flags & IFF_POINTOPOINT)
				info->rti_info[RTAX_BRD] =
				    nh->nh_ifa->ifa_dstaddr;
			rtm->rtm_index = ifp->if_index;
		} else {
			info->rti_info[RTAX_IFP] = NULL;
			info->rti_info[RTAX_IFA] = NULL;
		}
	} else if (ifp != NULL)
		rtm->rtm_index = ifp->if_index;

	/* Check if we need to realloc storage */
	rtsock_msg_buffer(rtm->rtm_type, info, NULL, &len);
	if (len > alloc_len) {
		struct rt_msghdr *tmp_rtm;

		tmp_rtm = malloc(len, M_TEMP, M_NOWAIT);
		if (tmp_rtm == NULL)
			return (ENOBUFS);
		bcopy(rtm, tmp_rtm, rtm->rtm_msglen);
		orig_rtm = rtm;
		rtm = tmp_rtm;
		alloc_len = len;

		/*
		 * Delay freeing original rtm as info contains
		 * data referencing it.
		 */
	}