+ return dodefaultroute(g, 'c');
+}
+
+/*
+ * dodefaultroute - talk to a routing socket to add/delete a default route.
+ */
+int
+dodefaultroute(g, cmd)
+ u_long g;
+ int cmd;
+{
+ int routes;
+ struct {
+ struct rt_msghdr hdr;
+ struct sockaddr_in dst;
+ struct sockaddr_in gway;
+ struct sockaddr_in mask;
+ } rtmsg;
+
+ if ((routes = socket(PF_ROUTE, SOCK_RAW, AF_INET)) < 0) {
+ syslog(LOG_ERR, "%cifdefaultroute: opening routing socket: %m", cmd);
+ return 0;
+ }
+
+ memset(&rtmsg, 0, sizeof(rtmsg));
+ rtmsg.hdr.rtm_type = cmd == 's'? RTM_ADD: RTM_DELETE;
+ rtmsg.hdr.rtm_flags = RTF_UP | RTF_GATEWAY;
+ rtmsg.hdr.rtm_version = RTM_VERSION;
+ rtmsg.hdr.rtm_seq = ++rtm_seq;
+ rtmsg.hdr.rtm_addrs = RTA_DST | RTA_GATEWAY | RTA_NETMASK;
+ rtmsg.dst.sin_len = sizeof(rtmsg.dst);
+ rtmsg.dst.sin_family = AF_INET;
+ rtmsg.gway.sin_len = sizeof(rtmsg.gway);
+ rtmsg.gway.sin_family = AF_INET;
+ rtmsg.gway.sin_addr.s_addr = g;
+ rtmsg.mask.sin_len = sizeof(rtmsg.dst);
+ rtmsg.mask.sin_family = AF_INET;
+
+ rtmsg.hdr.rtm_msglen = sizeof(rtmsg);
+ if (write(routes, &rtmsg, sizeof(rtmsg)) < 0) {
+ syslog(LOG_ERR, "%s default route: %m", cmd=='s'? "add": "delete");
+ close(routes);
+ return 0;
+ }
+
+ close(routes);
+ return 1;
+}
+
+#if RTM_VERSION >= 3
+
+/*
+ * sifproxyarp - Make a proxy ARP entry for the peer.
+ */
+static struct {
+ struct rt_msghdr hdr;
+ struct sockaddr_inarp dst;
+ struct sockaddr_dl hwa;
+ char extra[128];
+} arpmsg;
+
+static int arpmsg_valid;
+
+int
+sifproxyarp(unit, hisaddr)
+ int unit;
+ u_long hisaddr;
+{
+ int routes;
+ int l;
+
+ /*
+ * Get the hardware address of an interface on the same subnet
+ * as our local address.
+ */
+ memset(&arpmsg, 0, sizeof(arpmsg));
+ if (!get_ether_addr(hisaddr, &arpmsg.hwa)) {
+ syslog(LOG_ERR, "Cannot determine ethernet address for proxy ARP");
+ return 0;
+ }
+
+ if ((routes = socket(PF_ROUTE, SOCK_RAW, AF_INET)) < 0) {
+ syslog(LOG_ERR, "sifproxyarp: opening routing socket: %m");
+ return 0;
+ }
+
+ arpmsg.hdr.rtm_type = RTM_ADD;
+ arpmsg.hdr.rtm_flags = RTF_ANNOUNCE | RTF_HOST | RTF_STATIC;
+ arpmsg.hdr.rtm_version = RTM_VERSION;
+ arpmsg.hdr.rtm_seq = ++rtm_seq;
+ arpmsg.hdr.rtm_addrs = RTA_DST | RTA_GATEWAY;
+ arpmsg.hdr.rtm_inits = RTV_EXPIRE;
+ arpmsg.dst.sin_len = sizeof(struct sockaddr_inarp);
+ arpmsg.dst.sin_family = AF_INET;
+ arpmsg.dst.sin_addr.s_addr = hisaddr;
+ arpmsg.dst.sin_other = SIN_PROXY;
+
+ arpmsg.hdr.rtm_msglen = (char *) &arpmsg.hwa - (char *) &arpmsg
+ + arpmsg.hwa.sdl_len;
+ if (write(routes, &arpmsg, arpmsg.hdr.rtm_msglen) < 0) {
+ syslog(LOG_ERR, "add proxy arp entry: %m");
+ close(routes);
+ return 0;
+ }
+
+ close(routes);
+ arpmsg_valid = 1;
+ return 1;
+}
+
+/*
+ * cifproxyarp - Delete the proxy ARP entry for the peer.
+ */
+int
+cifproxyarp(unit, hisaddr)
+ int unit;
+ u_long hisaddr;
+{
+ int routes;
+
+ if (!arpmsg_valid)
+ return 0;
+ arpmsg_valid = 0;
+
+ arpmsg.hdr.rtm_type = RTM_DELETE;
+ arpmsg.hdr.rtm_seq = ++rtm_seq;
+
+ if ((routes = socket(PF_ROUTE, SOCK_RAW, AF_INET)) < 0) {
+ syslog(LOG_ERR, "sifproxyarp: opening routing socket: %m");
+ return 0;
+ }
+
+ if (write(routes, &arpmsg, arpmsg.hdr.rtm_msglen) < 0) {
+ syslog(LOG_ERR, "delete proxy arp entry: %m");
+ close(routes);
+ return 0;
+ }
+
+ close(routes);
+ return 1;