+ register u_long i = ntohl(sin->sin_addr.s_addr);
+ struct sockaddr oldaddr;
+ struct sockaddr_in netaddr;
+ int s = splimp(), error;
+
+ oldaddr = ia->ia_addr;
+ ia->ia_addr = *(struct sockaddr *)sin;
+
+ /*
+ * Give the interface a chance to initialize
+ * if this is its first address,
+ * and to validate the address if necessary.
+ */
+ if (ifp->if_ioctl && (error = (*ifp->if_ioctl)(ifp, SIOCSIFADDR, ia))) {
+ splx(s);
+ ia->ia_addr = oldaddr;
+ return (error);
+ }
+
+ /*
+ * Delete any previous route for an old address.
+ */
+ bzero((caddr_t)&netaddr, sizeof (netaddr));
+ netaddr.sin_family = AF_INET;
+ if (ia->ia_flags & IFA_ROUTE) {
+ if (ifp->if_flags & IFF_LOOPBACK)
+ rtinit(&oldaddr, &oldaddr, (int)SIOCDELRT, RTF_HOST);
+ else if (ifp->if_flags & IFF_POINTOPOINT)
+ rtinit(&ia->ia_dstaddr, &oldaddr, (int)SIOCDELRT,
+ RTF_HOST);
+ else {
+ netaddr.sin_addr = in_makeaddr(ia->ia_subnet,
+ INADDR_ANY);
+ rtinit((struct sockaddr *)&netaddr, &oldaddr,
+ (int)SIOCDELRT, 0);
+ }
+ ia->ia_flags &= ~IFA_ROUTE;
+ }
+ if (IN_CLASSA(i))
+ ia->ia_netmask = IN_CLASSA_NET;
+ else if (IN_CLASSB(i))
+ ia->ia_netmask = IN_CLASSB_NET;
+ else
+ ia->ia_netmask = IN_CLASSC_NET;
+ ia->ia_net = i & ia->ia_netmask;
+ /*
+ * The subnet mask includes at least the standard network part,
+ * but may already have been set to a larger value.
+ */
+ ia->ia_subnetmask |= ia->ia_netmask;
+ ia->ia_subnet = i & ia->ia_subnetmask;
+ if (ifp->if_flags & IFF_BROADCAST) {
+ ia->ia_broadaddr.sa_family = AF_INET;
+ ((struct sockaddr_in *)(&ia->ia_broadaddr))->sin_addr =
+ in_makeaddr(ia->ia_subnet, INADDR_BROADCAST);
+ ia->ia_netbroadcast.s_addr =
+ htonl(ia->ia_net | (INADDR_BROADCAST &~ ia->ia_netmask));
+ }
+ /*
+ * Add route for the network.
+ */
+ if (ifp->if_flags & IFF_LOOPBACK)
+ rtinit(&ia->ia_addr, &ia->ia_addr, (int)SIOCADDRT,
+ RTF_HOST|RTF_UP);
+ else if (ifp->if_flags & IFF_POINTOPOINT)
+ rtinit(&ia->ia_dstaddr, &ia->ia_addr, (int)SIOCADDRT,
+ RTF_HOST|RTF_UP);
+ else {
+ netaddr.sin_addr = in_makeaddr(ia->ia_subnet, INADDR_ANY);
+ rtinit((struct sockaddr *)&netaddr, &ia->ia_addr,
+ (int)SIOCADDRT, RTF_UP);
+ }
+ ia->ia_flags |= IFA_ROUTE;
+ splx(s);
+ return (0);
+}
+
+/*
+ * Return address info for specified internet network.
+ */
+struct in_ifaddr *
+in_iaonnetof(net)
+ u_long net;
+{
+ register struct in_ifaddr *ia;
+
+ for (ia = in_ifaddr; ia; ia = ia->ia_next)
+ if (ia->ia_subnet == net)
+ return (ia);
+ return ((struct in_ifaddr *)0);
+}
+
+/*
+ * Return 1 if the address might be a local broadcast address.
+ */
+in_broadcast(in)
+ struct in_addr in;
+{
+ register struct in_ifaddr *ia;
+ u_long t;
+
+ /*
+ * Look through the list of addresses for a match
+ * with a broadcast address.
+ */
+ for (ia = in_ifaddr; ia; ia = ia->ia_next)
+ if (ia->ia_ifp->if_flags & IFF_BROADCAST) {
+ if (satosin(&ia->ia_broadaddr)->sin_addr.s_addr == in.s_addr)
+ return (1);
+ /*
+ * Check for old-style (host 0) broadcast.
+ */
+ if ((t = ntohl(in.s_addr)) == ia->ia_subnet || t == ia->ia_net)
+ return (1);
+ }
+ if (in.s_addr == INADDR_BROADCAST || in.s_addr == INADDR_ANY)
+ return (1);
+ return (0);