/* $NetBSD: output.c,v 1.10 1996/08/10 01:29:26 thorpej Exp $ */ /* * Copyright (c) 1983, 1988, 1993 * The Regents of the University of California. All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * 3. All advertising materials mentioning features or use of this software * must display the following acknowledgement: * This product includes software developed by the University of * California, Berkeley and its contributors. * 4. Neither the name of the University nor the names of its contributors * may be used to endorse or promote products derived from this software * without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. */ #if !defined(lint) && !defined(sgi) #if 0 static char sccsid[] = "@(#)output.c 8.1 (Berkeley) 6/5/93"; #else static char rcsid[] = "$NetBSD: output.c,v 1.10 1996/08/10 01:29:26 thorpej Exp $"; #endif #endif /* not lint */ #include "defs.h" int update_seqno; /* walk the tree of routes with this for output */ struct { struct sockaddr_in to; naddr to_mask; naddr to_net; naddr to_std_mask; naddr to_std_net; struct interface *ifp; /* usually output interface */ struct ws_buf { /* info for each buffer */ struct rip *buf; struct netinfo *n; struct netinfo *base; struct netinfo *lim; enum output_type type; } v12, v2; char metric; /* adjust metrics by interface */ int npackets; u_int state; #define WS_ST_FLASH 0x001 /* send only changed routes */ #define WS_ST_RIP2_SAFE 0x002 /* send RIPv2 safe for RIPv1 */ #define WS_ST_RIP2_ALL 0x004 /* send full featured RIPv2 */ #define WS_ST_AG 0x008 /* ok to aggregate subnets */ #define WS_ST_SUPER_AG 0x010 /* ok to aggregate networks */ #define WS_ST_SUB_AG 0x020 /* aggregate subnets in odd case */ #define WS_ST_QUERY 0x040 /* responding to a query */ #define WS_ST_TO_ON_NET 0x080 /* sending onto one of our nets */ #define WS_ST_DEFAULT 0x100 /* faking a default */ #define WS_ST_PM_RDISC 0x200 /* poor-man's router discovery */ } ws; /* A buffer for what can be heard by both RIPv1 and RIPv2 listeners */ union pkt_buf ripv12_buf; /* Another for only RIPv2 listeners */ union pkt_buf rip_v2_buf; /* Send the contents of the global buffer via the non-multicast socket */ int /* <0 on failure */ output(enum output_type type, struct sockaddr_in *dst, /* send to here */ struct interface *ifp, struct rip *buf, int size) /* this many bytes */ { struct sockaddr_in sin; int flags; char *msg; int res; naddr tgt_mcast; int soc; int serrno; sin = *dst; if (sin.sin_port == 0) sin.sin_port = htons(RIP_PORT); #ifdef _HAVE_SIN_LEN if (sin.sin_len == 0) sin.sin_len = sizeof(sin); #endif soc = rip_sock; flags = 0; switch (type) { case OUT_QUERY: msg = "Answer Query"; if (soc < 0) soc = ifp->int_rip_sock; break; case OUT_UNICAST: msg = "Send"; if (soc < 0) soc = ifp->int_rip_sock; flags = MSG_DONTROUTE; break; case OUT_BROADCAST: if (ifp->int_if_flags & IFF_POINTOPOINT) { msg = "Send"; } else { msg = "Send bcast"; } flags = MSG_DONTROUTE; break; case OUT_MULTICAST: if (ifp->int_if_flags & IFF_POINTOPOINT) { msg = "Send pt-to-pt"; } else if (ifp->int_state & IS_DUP) { trace_act("abort multicast output via %s" " with duplicate address\n", ifp->int_name); return 0; } else { msg = "Send mcast"; if (rip_sock_mcast != ifp) { #ifdef MCAST_PPP_BUG /* Do not specifiy the primary interface * explicitly if we have the multicast * point-to-point kernel bug, since the * kernel will do the wrong thing if the * local address of a point-to-point link * is the same as the address of an ordinary * interface. */ if (ifp->int_addr == myaddr) { tgt_mcast = 0; } else #endif tgt_mcast = ifp->int_addr; if (0 > setsockopt(rip_sock, IPPROTO_IP, IP_MULTICAST_IF, &tgt_mcast, sizeof(tgt_mcast))) { serrno = errno; LOGERR("setsockopt(rip_sock," "IP_MULTICAST_IF)"); errno = serrno; ifp = 0; return -1; } rip_sock_mcast = ifp; } sin.sin_addr.s_addr = htonl(INADDR_RIP_GROUP); } break; default: /* Nothing; keep compilers happy. */ } trace_rip(msg, "to", &sin, ifp, buf, size); res = sendto(soc, buf, size, flags, (struct sockaddr *)&sin, sizeof(sin)); if (res < 0 && (ifp == 0 || !(ifp->int_state & IS_BROKE))) { serrno = errno; msglog("%s sendto(%s%s%s.%d): %s", msg, ifp != 0 ? ifp->int_name : "", ifp != 0 ? ", " : "", inet_ntoa(sin.sin_addr), ntohs(sin.sin_port), strerror(errno)); errno = serrno; } return res; } /* install authentication if appropriate */ static void set_auth(struct ws_buf *w) { if (ws.ifp != 0 && ws.ifp->int_passwd[0] != '\0' && (ws.state & WS_ST_RIP2_SAFE)) { w->n->n_family = RIP_AF_AUTH; ((struct netauth*)w->n)->a_type = RIP_AUTH_PW; bcopy(ws.ifp->int_passwd, ((struct netauth*)w->n)->au.au_pw, sizeof(((struct netauth*)w->n)->au.au_pw)); w->n++; } } /* Send the buffer */ static void supply_write(struct ws_buf *wb) { /* Output multicast only if legal. * If we would multcast and it would be illegal, then discard the * packet. */ switch (wb->type) { case NO_OUT_MULTICAST: trace_pkt("skip multicast to %s because impossible\n", naddr_ntoa(ws.to.sin_addr.s_addr)); break; case NO_OUT_RIPV2: break; default: if (output(wb->type, &ws.to, ws.ifp, wb->buf, ((char *)wb->n - (char*)wb->buf)) < 0 && ws.ifp != 0) if_sick(ws.ifp); ws.npackets++; break; } bzero(wb->n = wb->base, sizeof(*wb->n)*NETS_LEN); if (wb->buf->rip_vers == RIPv2) set_auth(wb); } /* put an entry into the packet */ static void supply_out(struct ag_info *ag) { int i; naddr mask, v1_mask, s_mask, dst_h, ddst_h; struct ws_buf *wb; /* Skip this route if doing a flash update and it and the routes * it aggregates have not changed recently. */ if (ag->ag_seqno < update_seqno && (ws.state & WS_ST_FLASH)) return; /* Skip this route if required by split-horizon */ if (ag->ag_state & AGS_SPLIT_HZ) return; dst_h = ag->ag_dst_h; mask = ag->ag_mask; v1_mask = ripv1_mask_host(htonl(dst_h), (ws.state & WS_ST_TO_ON_NET) ? ws.ifp : 0); s_mask = std_mask(htonl(dst_h)); i = 0; /* If we are sending RIPv2 packets that cannot (or must not) be * heard by RIPv1 listeners, do not worry about sub- or supernets. * Subnets (from other networks) can only be sent via multicast. * A pair of subnet routes might have been promoted so that they * are legal to send by RIPv1. * If RIPv1 is off, use the multicast buffer, unless this is the * fake default route and it is acting as a poor-man's router- * discovery mechanism. */ if (((ws.state & WS_ST_RIP2_ALL) && (dst_h != RIP_DEFAULT || !(ws.state & WS_ST_PM_RDISC))) || ((ag->ag_state & AGS_RIPV2) && v1_mask != mask)) { /* use the RIPv2-only buffer */ wb = &ws.v2; } else { /* use the RIPv1-or-RIPv2 buffer */ wb = &ws.v12; /* Convert supernet route into corresponding set of network * routes for RIPv1, but leave non-contiguous netmasks * to ag_check(). */ if (v1_mask > mask && mask + (mask & -mask) == 0) { ddst_h = v1_mask & -v1_mask; i = (v1_mask & ~mask)/ddst_h; if (i >= 1024) { /* Punt if we would have to generate an * unreasonable number of routes. */ #ifdef DEBUG msglog("sending %s to %s as-is instead" " of as %d routes", addrname(htonl(dst_h),mask,0), naddr_ntoa(ws.to.sin_addr.s_addr), i); #endif i = 0; } else { mask = v1_mask; } } } do { wb->n->n_family = RIP_AF_INET; wb->n->n_dst = htonl(dst_h); /* If the route is from router-discovery or we are * shutting down, admit only a bad metric. */ wb->n->n_metric = ((stopint || ag->ag_metric < 1) ? HOPCNT_INFINITY : ag->ag_metric); HTONL(wb->n->n_metric); if (wb->buf->rip_vers == RIPv2) { if (ag->ag_nhop != 0 && (ws.state & WS_ST_RIP2_SAFE) && ((ws.state & WS_ST_QUERY) || (ag->ag_nhop != ws.ifp->int_addr && on_net(ag->ag_nhop, ws.ifp->int_net, ws.ifp->int_mask)))) wb->n->n_nhop = ag->ag_nhop; if ((ws.state & WS_ST_RIP2_ALL) || mask != s_mask) wb->n->n_mask = htonl(mask); wb->n->n_tag = ag->ag_tag; } dst_h += ddst_h; if (++wb->n >= wb->lim) supply_write(wb); } while (i-- != 0); } /* supply one route from the table */ /* ARGSUSED */ static int walk_supply(struct radix_node *rn, void *argp) { #define RT ((struct rt_entry *)rn) #if 0 struct walkarg *w = argp; /* not used */ #endif u_short ags = 0; char metric, pref; naddr dst, nhop; /* Do not advertise the loopback interface * or external remote interfaces */ if (RT->rt_ifp != 0 && ((RT->rt_ifp->int_if_flags & IFF_LOOPBACK) || (RT->rt_ifp->int_state & IS_EXTERNAL)) && !(RT->rt_state & RS_MHOME)) return 0; /* If being quiet about our ability to forward, then * do not say anything unless responding to a query. */ if (!supplier && !(ws.state & WS_ST_QUERY)) return 0; dst = RT->rt_dst; /* do not collide with the fake default route */ if (dst == RIP_DEFAULT && (ws.state & WS_ST_DEFAULT)) return 0; if (RT->rt_state & RS_NET_SYN) { if (RT->rt_state & RS_NET_INT) { /* Do not send manual synthetic network routes * into the subnet. */ if (on_net(ws.to.sin_addr.s_addr, ntohl(dst), RT->rt_mask)) return 0; } else { /* Do not send automatic synthetic network routes * if they are not needed becaus no RIPv1 listeners * can hear them. */ if (ws.state & WS_ST_RIP2_ALL) return 0; /* Do not send automatic synthetic network routes to * the real subnet. */ if (on_net(ws.to.sin_addr.s_addr, ntohl(dst), RT->rt_mask)) return 0; } nhop = 0; } else { /* Advertise the next hop if this is not a route for one * of our interfaces and the next hop is on the same * network as the target. */ if (!(RT->rt_state & RS_IF) && RT->rt_gate != myaddr && RT->rt_gate != loopaddr) nhop = RT->rt_gate; else nhop = 0; } /* Adjust the outgoing metric by the cost of the link. */ pref = metric = RT->rt_metric + ws.metric; if (pref < HOPCNT_INFINITY) { /* Keep track of the best metric with which the * route has been advertised recently. */ if (RT->rt_poison_metric >= metric || RT->rt_poison_time <= now_garbage) { RT->rt_poison_time = now.tv_sec; RT->rt_poison_metric = RT->rt_metric; } } else { /* Do not advertise stable routes that will be ignored, * unless they are being held down and poisoned. If the * route recently was advertised with a metric that would * have been less than infinity through this interface, we * need to continue to advertise it in order to poison it. */ pref = RT->rt_poison_metric + ws.metric; if (pref >= HOPCNT_INFINITY) return 0; metric = HOPCNT_INFINITY; } if (RT->rt_state & RS_MHOME) { /* retain host route of multi-homed servers */ ; } else if (RT_ISHOST(RT)) { /* We should always aggregate the host routes * for the local end of our point-to-point links. * If we are suppressing host routes in general, then do so. * Avoid advertising host routes onto their own network, * where they should be handled by proxy-ARP. */ if ((RT->rt_state & RS_LOCAL) || ridhosts || (ws.state & WS_ST_SUPER_AG) || on_net(dst, ws.to_net, ws.to_mask)) ags |= AGS_SUPPRESS; if (ws.state & WS_ST_SUPER_AG) ags |= AGS_PROMOTE; } else if (ws.state & WS_ST_AG) { /* Aggregate network routes, if we are allowed. */ ags |= AGS_SUPPRESS; /* Generate supernets if allowed. * If we can be heard by RIPv1 systems, we will * later convert back to ordinary nets. * This unifies dealing with received supernets. */ if ((RT->rt_state & RS_SUBNET) || (ws.state & WS_ST_SUPER_AG)) ags |= AGS_PROMOTE; } /* Do not send RIPv1 advertisements of subnets to other * networks. If possible, multicast them by RIPv2. */ if ((RT->rt_state & RS_SUBNET) && !(ws.state & WS_ST_RIP2_ALL) && !on_net(dst, ws.to_std_net, ws.to_std_mask)) { ags |= AGS_RIPV2 | AGS_PROMOTE; if (ws.state & WS_ST_SUB_AG) ags |= AGS_SUPPRESS; } /* Do not send a route back to where it came from, except in * response to a query. This is "split-horizon". That means not * advertising back to the same network and so via the same interface. * * We want to suppress routes that might have been fragmented * from this route by a RIPv1 router and sent back to us, and so we * cannot forget this route here. Let the split-horizon route * aggregate (suppress) the fragmented routes and then itself be * forgotten. * * Include the routes for both ends of point-to-point interfaces * since the other side presumably knows them as well as we do. */ if (RT->rt_ifp == ws.ifp && ws.ifp != 0 && !(ws.state & WS_ST_QUERY) && (ws.state & WS_ST_TO_ON_NET) && (!(RT->rt_state & RS_IF) || ws.ifp->int_if_flags & IFF_POINTOPOINT)) { ags |= AGS_SPLIT_HZ; ags &= ~(AGS_PROMOTE | AGS_SUPPRESS); } ag_check(dst, RT->rt_mask, 0, nhop, metric, pref, RT->rt_seqno, RT->rt_tag, ags, supply_out); return 0; #undef RT } /* Supply dst with the contents of the routing tables. * If this won't fit in one packet, chop it up into several. */ void supply(struct sockaddr_in *dst, struct interface *ifp, /* output interface */ enum output_type type, int flash, /* 1=flash update */ int vers) /* RIP version */ { static int init = 1; struct rt_entry *rt; ws.state = 0; ws.to = *dst; ws.to_std_mask = std_mask(ws.to.sin_addr.s_addr); ws.to_std_net = ntohl(ws.to.sin_addr.s_addr) & ws.to_std_mask; if (ifp != 0) { ws.to_mask = ifp->int_mask; ws.to_net = ifp->int_net; if (on_net(ws.to.sin_addr.s_addr, ws.to_net, ws.to_mask)) ws.state |= WS_ST_TO_ON_NET; } else { ws.to_mask = ripv1_mask_net(ws.to.sin_addr.s_addr, 0); ws.to_net = ntohl(ws.to.sin_addr.s_addr) & ws.to_mask; rt = rtfind(dst->sin_addr.s_addr); if (rt) ifp = rt->rt_ifp; } ws.npackets = 0; if (flash) ws.state |= WS_ST_FLASH; if (type == OUT_QUERY) ws.state |= WS_ST_QUERY; if ((ws.ifp = ifp) == 0) { ws.metric = 1; } else { /* Adjust the advertised metric by the outgoing interface * metric. */ ws.metric = ifp->int_metric+1; } if (init) { init = 0; bzero(&ripv12_buf, sizeof(ripv12_buf)); ripv12_buf.rip.rip_cmd = RIPCMD_RESPONSE; ws.v12.buf = &ripv12_buf.rip; ws.v12.base = &ws.v12.buf->rip_nets[0]; ws.v12.lim = ws.v12.base + NETS_LEN; bzero(&rip_v2_buf, sizeof(rip_v2_buf)); rip_v2_buf.rip.rip_cmd = RIPCMD_RESPONSE; rip_v2_buf.rip.rip_vers = RIPv2; ws.v2.buf = &rip_v2_buf.rip; ws.v2.base = &ws.v2.buf->rip_nets[0]; ws.v2.lim = ws.v2.base + NETS_LEN; } ripv12_buf.rip.rip_vers = vers; ws.v12.n = ws.v12.base; set_auth(&ws.v12); ws.v2.n = ws.v2.base; set_auth(&ws.v2); switch (type) { case OUT_BROADCAST: ws.v2.type = ((ws.ifp != 0 && (ws.ifp->int_if_flags & IFF_MULTICAST)) ? OUT_MULTICAST : NO_OUT_MULTICAST); ws.v12.type = OUT_BROADCAST; break; case OUT_MULTICAST: ws.v2.type = ((ws.ifp != 0 && (ws.ifp->int_if_flags & IFF_MULTICAST)) ? OUT_MULTICAST : NO_OUT_MULTICAST); ws.v12.type = OUT_BROADCAST; break; case OUT_UNICAST: case OUT_QUERY: ws.v2.type = (vers == RIPv2) ? type : NO_OUT_RIPV2; ws.v12.type = type; break; default: ws.v2.type = type; ws.v12.type = type; break; } if (vers == RIPv2) { /* if asked to send RIPv2, send at least that which can * be safely heard by RIPv1 listeners. */ ws.state |= WS_ST_RIP2_SAFE; /* full RIPv2 only if cannot be heard by RIPv1 listeners */ if (type != OUT_BROADCAST) ws.state |= WS_ST_RIP2_ALL; if (!(ws.state & WS_ST_TO_ON_NET)) { ws.state |= (WS_ST_AG | WS_ST_SUPER_AG); } else if (ws.ifp == 0 || !(ws.ifp->int_state & IS_NO_AG)) { ws.state |= WS_ST_AG; if (type != OUT_BROADCAST && (ws.ifp == 0 || !(ws.ifp->int_state & IS_NO_SUPER_AG))) ws.state |= WS_ST_SUPER_AG; } } else if (ws.ifp == 0 || !(ws.ifp->int_state & IS_NO_AG)) { ws.state |= WS_ST_SUB_AG; } if (supplier) { /* Fake a default route if asked, and if there is not * a better, real default route. */ if (ifp->int_d_metric != 0 && (0 == (rt = rtget(RIP_DEFAULT, 0)) || rt->rt_metric+ws.metric >= ifp->int_d_metric)) { ws.state |= WS_ST_DEFAULT; ag_check(0, 0, 0, 0, ifp->int_d_metric,ifp->int_d_metric, 0, 0, 0, supply_out); } if ((ws.state & WS_ST_RIP2_ALL) && (ifp->int_state & IS_PM_RDISC)) { ws.state |= WS_ST_PM_RDISC; ripv12_buf.rip.rip_vers = RIPv1; } } (void)rn_walktree(rhead, walk_supply, 0); ag_flush(0,0,supply_out); /* Flush the packet buffers, provided they are not empty and * do not contain only the password. */ if (ws.v12.n != ws.v12.base && (ws.v12.n > ws.v12.base+1 || ws.v12.n->n_family != RIP_AF_AUTH)) supply_write(&ws.v12); if (ws.v2.n != ws.v2.base && (ws.v2.n > ws.v2.base+1 || ws.v2.n->n_family != RIP_AF_AUTH)) supply_write(&ws.v2); /* If we sent nothing and this is an answer to a query, send * an empty buffer. */ if (ws.npackets == 0 && (ws.state & WS_ST_QUERY)) supply_write(&ws.v12); } /* send all of the routing table or just do a flash update */ void rip_bcast(int flash) { #ifdef _HAVE_SIN_LEN static struct sockaddr_in dst = {sizeof(dst), AF_INET}; #else static struct sockaddr_in dst = {AF_INET}; #endif struct interface *ifp; enum output_type type; int vers; struct timeval rtime; need_flash = 0; intvl_random(&rtime, MIN_WAITTIME, MAX_WAITTIME); no_flash = rtime; timevaladd(&no_flash, &now); if (rip_sock < 0) return; trace_act("send %s and inhibit dynamic updates for %.3f sec\n", flash ? "dynamic update" : "all routes", rtime.tv_sec + ((float)rtime.tv_usec)/1000000.0); for (ifp = ifnet; ifp != 0; ifp = ifp->int_next) { /* skip interfaces not doing RIP, those already queried, * and aliases. Do try broken interfaces to see * if they have healed. */ if (0 != (ifp->int_state & (IS_PASSIVE | IS_ALIAS))) continue; /* skip turned off interfaces */ if (!iff_alive(ifp->int_if_flags)) continue; /* default to RIPv1 output */ if (ifp->int_state & IS_NO_RIPV1_OUT) { /* Say nothing if this interface is turned off */ if (ifp->int_state & IS_NO_RIPV2_OUT) continue; vers = RIPv2; } else { vers = RIPv1; } if (ifp->int_if_flags & IFF_BROADCAST) { /* ordinary, hardware interface */ dst.sin_addr.s_addr = ifp->int_brdaddr; /* if RIPv1 is not turned off, then broadcast so * that RIPv1 listeners can hear. */ if (vers == RIPv2 && (ifp->int_state & IS_NO_RIPV1_OUT)) { type = OUT_MULTICAST; } else { type = OUT_BROADCAST; } } else if (ifp->int_if_flags & IFF_POINTOPOINT) { /* point-to-point hardware interface */ dst.sin_addr.s_addr = ifp->int_dstaddr; type = OUT_UNICAST; } else { /* remote interface */ dst.sin_addr.s_addr = ifp->int_addr; type = OUT_UNICAST; } supply(&dst, ifp, type, flash, vers); } update_seqno++; /* all routes are up to date */ } /* Ask for routes * Do it only once to an interface, and not even after the interface * was broken and recovered. */ void rip_query(void) { #ifdef _HAVE_SIN_LEN static struct sockaddr_in dst = {sizeof(dst), AF_INET}; #else static struct sockaddr_in dst = {AF_INET}; #endif struct interface *ifp; struct rip buf; enum output_type type; if (rip_sock < 0) return; bzero(&buf, sizeof(buf)); for (ifp = ifnet; ifp; ifp = ifp->int_next) { /* skip interfaces not doing RIP, those already queried, * and aliases. Do try broken interfaces to see * if they have healed. */ if (0 != (ifp->int_state & (IS_RIP_QUERIED | IS_PASSIVE | IS_ALIAS))) continue; /* skip turned off interfaces */ if (!iff_alive(ifp->int_if_flags)) continue; /* default to RIPv1 output */ if (ifp->int_state & IS_NO_RIPV2_OUT) { /* Say nothing if this interface is turned off */ if (ifp->int_state & IS_NO_RIPV1_OUT) continue; buf.rip_vers = RIPv1; } else { buf.rip_vers = RIPv2; } buf.rip_cmd = RIPCMD_REQUEST; buf.rip_nets[0].n_family = RIP_AF_UNSPEC; buf.rip_nets[0].n_metric = htonl(HOPCNT_INFINITY); if (ifp->int_if_flags & IFF_BROADCAST) { /* ordinary, hardware interface */ dst.sin_addr.s_addr = ifp->int_brdaddr; /* if RIPv1 is not turned off, then broadcast so * that RIPv1 listeners can hear. */ if (buf.rip_vers == RIPv2 && (ifp->int_state & IS_NO_RIPV1_OUT)) { type = OUT_MULTICAST; } else { type = OUT_BROADCAST; } } else if (ifp->int_if_flags & IFF_POINTOPOINT) { /* point-to-point hardware interface */ dst.sin_addr.s_addr = ifp->int_dstaddr; type = OUT_UNICAST; } else { /* remote interface */ dst.sin_addr.s_addr = ifp->int_addr; type = OUT_UNICAST; } ifp->int_state |= IS_RIP_QUERIED; if (output(type, &dst, ifp, &buf, sizeof(buf)) < 0) if_sick(ifp); } }