/* * sys-bsd.c - System-dependent procedures for setting up * PPP interfaces on bsd-4.4-ish systems (including 386BSD, NetBSD, etc.) * * Copyright (c) 1989 Carnegie Mellon University. * All rights reserved. * * Redistribution and use in source and binary forms are permitted * provided that the above copyright notice and this paragraph are * duplicated in all such forms and that any documentation, * advertising materials, and other materials related to such * distribution and use acknowledge that the software was developed * by Carnegie Mellon University. The name of the * University may not be used to endorse or promote products derived * from this software without specific prior written permission. * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED * WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE. * * $Id: arp.c,v 1.14 1997/08/31 22:59:12 brian Exp $ * */ /* * TODO: */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #ifdef __bsdi__ #include #endif #include #include #if RTM_VERSION >= 3 #include #endif #include "log.h" static int rtm_seq; static int get_ether_addr(int, u_long, struct sockaddr_dl *); #define BCOPY(s, d, l) memcpy(d, s, l) #define BZERO(s, n) memset(s, 0, n) /* * SET_SA_FAMILY - set the sa_family field of a struct sockaddr, * if it exists. */ #define SET_SA_FAMILY(addr, family) \ BZERO((char *) &(addr), sizeof(addr)); \ addr.sa_family = (family); \ addr.sa_len = sizeof(addr); #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(int unit, u_long hisaddr) { int routes; /* * Get the hardware address of an interface on the same subnet as our local * address. */ memset(&arpmsg, 0, sizeof(arpmsg)); if (!get_ether_addr(unit, hisaddr, &arpmsg.hwa)) { LogPrintf(LogERROR, "Cannot determine ethernet address for proxy ARP\n"); return 0; } if ((routes = socket(PF_ROUTE, SOCK_RAW, AF_INET)) < 0) { LogPrintf(LogERROR, "sifproxyarp: opening routing socket: %s\n", strerror(errno)); 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) { LogPrintf(LogERROR, "Add proxy arp entry: %s\n", strerror(errno)); close(routes); return 0; } close(routes); arpmsg_valid = 1; return 1; } /* * cifproxyarp - Delete the proxy ARP entry for the peer. */ int cifproxyarp(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) { LogPrintf(LogERROR, "sifproxyarp: opening routing socket: %s\n", strerror(errno)); return 0; } if (write(routes, &arpmsg, arpmsg.hdr.rtm_msglen) < 0) { LogPrintf(LogERROR, "Delete proxy arp entry: %s\n", strerror(errno)); close(routes); return 0; } close(routes); return 1; } #else /* RTM_VERSION */ /* * sifproxyarp - Make a proxy ARP entry for the peer. */ int sifproxyarp(int unit, u_long hisaddr) { struct arpreq arpreq; struct { struct sockaddr_dl sdl; char space[128]; } dls; BZERO(&arpreq, sizeof(arpreq)); /* * Get the hardware address of an interface on the same subnet as our local * address. */ if (!get_ether_addr(unit, hisaddr, &dls.sdl)) { LogPrintf(LOG_PHASE_BIT, "Cannot determine ethernet address for proxy ARP\n"); return 0; } arpreq.arp_ha.sa_len = sizeof(struct sockaddr); arpreq.arp_ha.sa_family = AF_UNSPEC; BCOPY(LLADDR(&dls.sdl), arpreq.arp_ha.sa_data, dls.sdl.sdl_alen); SET_SA_FAMILY(arpreq.arp_pa, AF_INET); ((struct sockaddr_in *) & arpreq.arp_pa)->sin_addr.s_addr = hisaddr; arpreq.arp_flags = ATF_PERM | ATF_PUBL; if (ioctl(unit, SIOCSARP, (caddr_t) & arpreq) < 0) { LogPrintf(LogERROR, "sifproxyarp: ioctl(SIOCSARP): %s\n", strerror(errno)); return 0; } return 1; } /* * cifproxyarp - Delete the proxy ARP entry for the peer. */ int cifproxyarp(int unit, u_long hisaddr) { struct arpreq arpreq; BZERO(&arpreq, sizeof(arpreq)); SET_SA_FAMILY(arpreq.arp_pa, AF_INET); ((struct sockaddr_in *) & arpreq.arp_pa)->sin_addr.s_addr = hisaddr; if (ioctl(unit, SIOCDARP, (caddr_t) & arpreq) < 0) { LogPrintf(LogERROR, "cifproxyarp: ioctl(SIOCDARP): %s\n", strerror(errno)); return 0; } return 1; } #endif /* RTM_VERSION */ /* * get_ether_addr - get the hardware address of an interface on the * the same subnet as ipaddr. */ #define MAX_IFS 32 int get_ether_addr(int s, u_long ipaddr, struct sockaddr_dl * hwaddr) { struct ifreq *ifr, *ifend, *ifp; u_long ina, mask; struct sockaddr_dl *dla; struct ifreq ifreq; struct ifconf ifc; struct ifreq ifs[MAX_IFS]; ifc.ifc_len = sizeof(ifs); ifc.ifc_req = ifs; if (ioctl(s, SIOCGIFCONF, &ifc) < 0) { LogPrintf(LogERROR, "get_ether_addr: ioctl(SIOCGIFCONF): %s\n", strerror(errno)); return 0; } /* * Scan through looking for an interface with an Internet address on the * same subnet as `ipaddr'. */ ifend = (struct ifreq *) (ifc.ifc_buf + ifc.ifc_len); for (ifr = ifc.ifc_req; ifr < ifend;) { if (ifr->ifr_addr.sa_family == AF_INET) { ina = ((struct sockaddr_in *) & ifr->ifr_addr)->sin_addr.s_addr; strncpy(ifreq.ifr_name, ifr->ifr_name, sizeof(ifreq.ifr_name)); ifreq.ifr_name[sizeof(ifreq.ifr_name) - 1] = '\0'; /* * Check that the interface is up, and not point-to-point or loopback. */ if (ioctl(s, SIOCGIFFLAGS, &ifreq) < 0) continue; if ((ifreq.ifr_flags & (IFF_UP | IFF_BROADCAST | IFF_POINTOPOINT | IFF_LOOPBACK | IFF_NOARP)) != (IFF_UP | IFF_BROADCAST)) goto nextif; /* * Get its netmask and check that it's on the right subnet. */ if (ioctl(s, SIOCGIFNETMASK, &ifreq) < 0) continue; mask = ((struct sockaddr_in *) & ifreq.ifr_addr)->sin_addr.s_addr; if ((ipaddr & mask) != (ina & mask)) goto nextif; break; } nextif: ifr = (struct ifreq *) ((char *) &ifr->ifr_addr + ifr->ifr_addr.sa_len); } if (ifr >= ifend) return 0; LogPrintf(LogPHASE, "Found interface %s for proxy arp\n", ifr->ifr_name); /* * Now scan through again looking for a link-level address for this * interface. */ ifp = ifr; for (ifr = ifc.ifc_req; ifr < ifend;) { if (strcmp(ifp->ifr_name, ifr->ifr_name) == 0 && ifr->ifr_addr.sa_family == AF_LINK) { /* * Found the link-level address - copy it out */ dla = (struct sockaddr_dl *) & ifr->ifr_addr; #ifdef __bsdi__ if (dla->sdl_alen == 0) kmemgetether(ifr->ifr_name, dla); #endif BCOPY(dla, hwaddr, dla->sdl_len); return 1; } ifr = (struct ifreq *) ((char *) &ifr->ifr_addr + ifr->ifr_addr.sa_len); } return 0; } #ifdef __bsdi__ #include struct nlist nl[] = { #define N_IFNET 0 {"_ifnet"}, "", }; kvm_t *kvmd; /* * Read kernel memory, return 0 on success. */ int kread(u_long addr, char *buf, int size) { if (kvm_read(kvmd, addr, buf, size) != size) { /* XXX this duplicates kvm_read's error printout */ LogPrintf(LogERROR, "kvm_read %s\n", kvm_geterr(kvmd)); return -1; } return 0; } void kmemgetether(char *ifname, struct sockaddr_dl * dlo) { struct ifnet ifnet; int n; u_long addr, ifaddraddr, ifnetfound, ifaddrfound; char name[16 + 32]; struct sockaddr *sa; char *cp; struct sockaddr_dl *sdl; union { struct ifaddr ifa; struct in_ifaddr in; } ifaddr; struct arpcom ac; kvmd = kvm_open(NULL, NULL, NULL, O_RDONLY, NULL); if (kvmd) { n = kvm_nlist(kvmd, nl); if (n >= 0) { addr = nl[N_IFNET].n_value; kread(addr, (char *) &addr, sizeof(addr)); ifaddraddr = ifnetfound = 0; while (addr || ifaddraddr) { ifnetfound = addr; if (ifaddraddr == 0) { if (kread(addr, (char *) &ifnet, sizeof(ifnet)) || kread((u_long) ifnet.if_name, name, 16)) return; name[15] = 0; addr = (u_long) ifnet.if_next; cp = (char *) index(name, '\0'); cp += sprintf(cp, "%d", ifnet.if_unit); *cp = '\0'; ifaddraddr = (u_long) ifnet.if_addrlist; } ifaddrfound = ifaddraddr; if (ifaddraddr) { if (kread(ifaddraddr, (char *) &ifaddr, sizeof ifaddr)) { ifaddraddr = 0; continue; } #define CP(x) ((char *)(x)) cp = (CP(ifaddr.ifa.ifa_addr) - CP(ifaddraddr)) + CP(&ifaddr); sa = (struct sockaddr *) cp; if (sa->sa_family == AF_LINK && strcmp(ifname, name) == 0) { sdl = (struct sockaddr_dl *) sa; cp = (char *) LLADDR(sdl); n = sdl->sdl_alen; if (ifnet.if_type == IFT_ETHER) { if (n == 0) { kread(ifnetfound, (char *) &ac, sizeof(ac)); cp = (char *) LLADDR(sdl); bcopy((char *) ac.ac_enaddr, cp, 6); sdl->sdl_alen = 6; } bcopy(sdl, dlo, sizeof(*sdl)); return; } } ifaddraddr = (u_long) ifaddr.ifa.ifa_next; } } } } } #endif #ifdef DEBUG main() { u_long ipaddr; int s; s = socket(AF_INET, SOCK_DGRAM, 0); ipaddr = inet_addr("192.168.1.32"); sifproxyarp(s, ipaddr); close(s); } #endif