/* * Copyright (c) 1990, 1991, 1992, 1993, 1996 * 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: (1) source code distributions * retain the above copyright notice and this paragraph in its entirety, (2) * distributions including binary code include the above copyright notice and * this paragraph in its entirety in the documentation or other materials * provided with the distribution * * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR IMPLIED * WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. */ #if 0 #ifndef lint static const char copyright[] = "@(#) Copyright (c) 1990, 1991, 1992, 1993, 1996\n\ The Regents of the University of California. All rights reserved.\n"; #endif /* not lint */ #endif #include __FBSDID("$FreeBSD$"); /* * rarpd - Reverse ARP Daemon * * Usage: rarpd -a [-dfsv] [-t directory] [-P pidfile] [hostname] * rarpd [-dfsv] [-t directory] [-P pidfile] interface [hostname] * * 'hostname' is optional solely for backwards compatibility with Sun's rarpd. * Currently, the argument is ignored. */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include /* Cast a struct sockaddr to a struct sockaddr_in */ #define SATOSIN(sa) ((struct sockaddr_in *)(sa)) #ifndef TFTP_DIR #define TFTP_DIR "/tftpboot" #endif #define ARPSECS (20 * 60) /* as per code in netinet/if_ether.c */ #define REVARP_REQUEST ARPOP_REVREQUEST #define REVARP_REPLY ARPOP_REVREPLY /* * The structure for each interface. */ struct if_info { struct if_info *ii_next; int ii_fd; /* BPF file descriptor */ in_addr_t ii_ipaddr; /* IP address */ in_addr_t ii_netmask; /* subnet or net mask */ u_char ii_eaddr[ETHER_ADDR_LEN]; /* ethernet address */ char ii_ifname[IF_NAMESIZE]; }; /* * The list of all interfaces that are being listened to. rarp_loop() * "selects" on the descriptors in this list. */ static struct if_info *iflist; static int verbose; /* verbose messages */ static const char *tftp_dir = TFTP_DIR; /* tftp directory */ static int dflag; /* messages to stdout/stderr, not syslog(3) */ static int sflag; /* ignore /tftpboot */ static u_char zero[6]; static char pidfile_buf[PATH_MAX]; static char *pidfile; #define RARPD_PIDFILE "/var/run/rarpd.%s.pid" static struct pidfh *pidfile_fh; static int bpf_open(void); static in_addr_t choose_ipaddr(in_addr_t **, in_addr_t, in_addr_t); static char *eatoa(u_char *); static int expand_syslog_m(const char *fmt, char **newfmt); static void init(char *); static void init_one(struct ifaddrs *, char *, int); static char *intoa(in_addr_t); static in_addr_t ipaddrtonetmask(in_addr_t); static void logmsg(int, const char *, ...) __printflike(2, 3); static int rarp_bootable(in_addr_t); static int rarp_check(u_char *, u_int); static void rarp_loop(void); static int rarp_open(char *); static void rarp_process(struct if_info *, u_char *, u_int); static void rarp_reply(struct if_info *, struct ether_header *, in_addr_t, u_int); static void update_arptab(u_char *, in_addr_t); static void usage(void); int main(int argc, char *argv[]) { int op; char *ifname, *name; int aflag = 0; /* listen on "all" interfaces */ int fflag = 0; /* don't fork */ if ((name = strrchr(argv[0], '/')) != NULL) ++name; else name = argv[0]; if (*name == '-') ++name; /* * All error reporting is done through syslog, unless -d is specified */ openlog(name, LOG_PID | LOG_CONS, LOG_DAEMON); opterr = 0; while ((op = getopt(argc, argv, "adfsP:t:v")) != -1) switch (op) { case 'a': ++aflag; break; case 'd': ++dflag; break; case 'f': ++fflag; break; case 's': ++sflag; break; case 'P': strncpy(pidfile_buf, optarg, sizeof(pidfile_buf) - 1); pidfile_buf[sizeof(pidfile_buf) - 1] = '\0'; pidfile = pidfile_buf; break; case 't': tftp_dir = optarg; break; case 'v': ++verbose; break; default: usage(); /* NOTREACHED */ } argc -= optind; argv += optind; ifname = (aflag == 0) ? argv[0] : NULL; if ((aflag && ifname) || (!aflag && ifname == NULL)) usage(); init(ifname); if (!fflag) { if (pidfile == NULL && ifname != NULL && aflag == 0) { snprintf(pidfile_buf, sizeof(pidfile_buf) - 1, RARPD_PIDFILE, ifname); pidfile_buf[sizeof(pidfile_buf) - 1] = '\0'; pidfile = pidfile_buf; } /* If pidfile == NULL, /var/run/.pid will be used. */ pidfile_fh = pidfile_open(pidfile, 0600, NULL); if (pidfile_fh == NULL) logmsg(LOG_ERR, "Cannot open or create pidfile: %s", (pidfile == NULL) ? "/var/run/rarpd.pid" : pidfile); if (daemon(0,0)) { logmsg(LOG_ERR, "cannot fork"); pidfile_remove(pidfile_fh); exit(1); } pidfile_write(pidfile_fh); } rarp_loop(); return(0); } /* * Add to the interface list. */ static void init_one(struct ifaddrs *ifa, char *target, int pass1) { struct if_info *ii, *ii2; struct sockaddr_dl *ll; int family; family = ifa->ifa_addr->sa_family; switch (family) { case AF_INET: if (pass1) /* Consider only AF_LINK during pass1. */ return; /* FALLTHROUGH */ case AF_LINK: if (!(ifa->ifa_flags & IFF_UP) || (ifa->ifa_flags & (IFF_LOOPBACK | IFF_POINTOPOINT))) return; break; default: return; } /* Don't bother going any further if not the target interface */ if (target != NULL && strcmp(ifa->ifa_name, target) != 0) return; /* Look for interface in list */ for (ii = iflist; ii != NULL; ii = ii->ii_next) if (strcmp(ifa->ifa_name, ii->ii_ifname) == 0) break; if (pass1 && ii != NULL) /* We've already seen that interface once. */ return; /* Allocate a new one if not found */ if (ii == NULL) { ii = (struct if_info *)malloc(sizeof(*ii)); if (ii == NULL) { logmsg(LOG_ERR, "malloc: %m"); pidfile_remove(pidfile_fh); exit(1); } bzero(ii, sizeof(*ii)); ii->ii_fd = -1; strlcpy(ii->ii_ifname, ifa->ifa_name, sizeof(ii->ii_ifname)); ii->ii_next = iflist; iflist = ii; } else if (!pass1 && ii->ii_ipaddr != 0) { /* * Second AF_INET definition for that interface: clone * the existing one, and work on that cloned one. * This must be another IP address for this interface, * so avoid killing the previous configuration. */ ii2 = (struct if_info *)malloc(sizeof(*ii2)); if (ii2 == NULL) { logmsg(LOG_ERR, "malloc: %m"); pidfile_remove(pidfile_fh); exit(1); } memcpy(ii2, ii, sizeof(*ii2)); ii2->ii_fd = -1; ii2->ii_next = iflist; iflist = ii2; ii = ii2; } switch (family) { case AF_INET: ii->ii_ipaddr = SATOSIN(ifa->ifa_addr)->sin_addr.s_addr; ii->ii_netmask = SATOSIN(ifa->ifa_netmask)->sin_addr.s_addr; if (ii->ii_netmask == 0) ii->ii_netmask = ipaddrtonetmask(ii->ii_ipaddr); if (ii->ii_fd < 0) ii->ii_fd = rarp_open(ii->ii_ifname); break; case AF_LINK: ll = (struct sockaddr_dl *)ifa->ifa_addr; switch (ll->sdl_type) { case IFT_ETHER: case IFT_L2VLAN: bcopy(LLADDR(ll), ii->ii_eaddr, 6); } break; } } /* * Initialize all "candidate" interfaces that are in the system * configuration list. A "candidate" is up, not loopback and not * point to point. */ static void init(char *target) { struct if_info *ii, *nii, *lii; struct ifaddrs *ifhead, *ifa; int error; error = getifaddrs(&ifhead); if (error) { logmsg(LOG_ERR, "getifaddrs: %m"); pidfile_remove(pidfile_fh); exit(1); } /* * We make two passes over the list we have got. In the first * one, we only collect AF_LINK interfaces, and initialize our * list of interfaces from them. In the second pass, we * collect the actual IP addresses from the AF_INET * interfaces, and allow for the same interface name to appear * multiple times (in case of more than one IP address). */ for (ifa = ifhead; ifa != NULL; ifa = ifa->ifa_next) init_one(ifa, target, 1); for (ifa = ifhead; ifa != NULL; ifa = ifa->ifa_next) init_one(ifa, target, 0); freeifaddrs(ifhead); /* Throw away incomplete interfaces */ lii = NULL; for (ii = iflist; ii != NULL; ii = nii) { nii = ii->ii_next; if (ii->ii_ipaddr == 0 || bcmp(ii->ii_eaddr, zero, 6) == 0) { if (lii == NULL) iflist = nii; else lii->ii_next = nii; if (ii->ii_fd >= 0) close(ii->ii_fd); free(ii); continue; } lii = ii; } /* Verbose stuff */ if (verbose) for (ii = iflist; ii != NULL; ii = ii->ii_next) logmsg(LOG_DEBUG, "%s %s 0x%08x %s", ii->ii_ifname, intoa(ntohl(ii->ii_ipaddr)), (in_addr_t)ntohl(ii->ii_netmask), eatoa(ii->ii_eaddr)); } static void usage(void) { (void)fprintf(stderr, "%s\n%s\n", "usage: rarpd -a [-dfsv] [-t directory] [-P pidfile]", " rarpd [-dfsv] [-t directory] [-P pidfile] interface"); exit(1); } static int bpf_open(void) { int fd; int n = 0; char device[sizeof "/dev/bpf000"]; /* * Go through all the minors and find one that isn't in use. */ do { (void)sprintf(device, "/dev/bpf%d", n++); fd = open(device, O_RDWR); } while ((fd == -1) && (errno == EBUSY)); if (fd == -1) { logmsg(LOG_ERR, "%s: %m", device); pidfile_remove(pidfile_fh); exit(1); } return fd; } /* * Open a BPF file and attach it to the interface named 'device'. * Set immediate mode, and set a filter that accepts only RARP requests. */ static int rarp_open(char *device) { int fd; struct ifreq ifr; u_int dlt; int immediate; static struct bpf_insn insns[] = { BPF_STMT(BPF_LD|BPF_H|BPF_ABS, 12), BPF_JUMP(BPF_JMP|BPF_JEQ|BPF_K, ETHERTYPE_REVARP, 0, 3), BPF_STMT(BPF_LD|BPF_H|BPF_ABS, 20), BPF_JUMP(BPF_JMP|BPF_JEQ|BPF_K, REVARP_REQUEST, 0, 1), BPF_STMT(BPF_RET|BPF_K, sizeof(struct ether_arp) + sizeof(struct ether_header)), BPF_STMT(BPF_RET|BPF_K, 0), }; static struct bpf_program filter = { sizeof insns / sizeof(insns[0]), insns }; fd = bpf_open(); /* * Set immediate mode so packets are processed as they arrive. */ immediate = 1; if (ioctl(fd, BIOCIMMEDIATE, &immediate) == -1) { logmsg(LOG_ERR, "BIOCIMMEDIATE: %m"); goto rarp_open_err; } strlcpy(ifr.ifr_name, device, sizeof(ifr.ifr_name)); if (ioctl(fd, BIOCSETIF, (caddr_t)&ifr) == -1) { logmsg(LOG_ERR, "BIOCSETIF: %m"); goto rarp_open_err; } /* * Check that the data link layer is an Ethernet; this code won't * work with anything else. */ if (ioctl(fd, BIOCGDLT, (caddr_t)&dlt) == -1) { logmsg(LOG_ERR, "BIOCGDLT: %m"); goto rarp_open_err; } if (dlt != DLT_EN10MB) { logmsg(LOG_ERR, "%s is not an ethernet", device); goto rarp_open_err; } /* * Set filter program. */ if (ioctl(fd, BIOCSETF, (caddr_t)&filter) == -1) { logmsg(LOG_ERR, "BIOCSETF: %m"); goto rarp_open_err; } return fd; rarp_open_err: pidfile_remove(pidfile_fh); exit(1); } /* * Perform various sanity checks on the RARP request packet. Return * false on failure and log the reason. */ static int rarp_check(u_char *p, u_int len) { struct ether_header *ep = (struct ether_header *)p; struct ether_arp *ap = (struct ether_arp *)(p + sizeof(*ep)); if (len < sizeof(*ep) + sizeof(*ap)) { logmsg(LOG_ERR, "truncated request, got %u, expected %lu", len, (u_long)(sizeof(*ep) + sizeof(*ap))); return 0; } /* * XXX This test might be better off broken out... */ if (ntohs(ep->ether_type) != ETHERTYPE_REVARP || ntohs(ap->arp_hrd) != ARPHRD_ETHER || ntohs(ap->arp_op) != REVARP_REQUEST || ntohs(ap->arp_pro) != ETHERTYPE_IP || ap->arp_hln != 6 || ap->arp_pln != 4) { logmsg(LOG_DEBUG, "request fails sanity check"); return 0; } if (bcmp((char *)&ep->ether_shost, (char *)&ap->arp_sha, 6) != 0) { logmsg(LOG_DEBUG, "ether/arp sender address mismatch"); return 0; } if (bcmp((char *)&ap->arp_sha, (char *)&ap->arp_tha, 6) != 0) { logmsg(LOG_DEBUG, "ether/arp target address mismatch"); return 0; } return 1; } /* * Loop indefinitely listening for RARP requests on the * interfaces in 'iflist'. */ static void rarp_loop(void) { u_char *buf, *bp, *ep; int cc, fd; fd_set fds, listeners; int bufsize, maxfd = 0; struct if_info *ii; if (iflist == NULL) { logmsg(LOG_ERR, "no interfaces"); goto rarpd_loop_err; } if (ioctl(iflist->ii_fd, BIOCGBLEN, (caddr_t)&bufsize) == -1) { logmsg(LOG_ERR, "BIOCGBLEN: %m"); goto rarpd_loop_err; } buf = malloc(bufsize); if (buf == NULL) { logmsg(LOG_ERR, "malloc: %m"); goto rarpd_loop_err; } while (1) { /* * Find the highest numbered file descriptor for select(). * Initialize the set of descriptors to listen to. */ FD_ZERO(&fds); for (ii = iflist; ii != NULL; ii = ii->ii_next) { FD_SET(ii->ii_fd, &fds); if (ii->ii_fd > maxfd) maxfd = ii->ii_fd; } listeners = fds; if (select(maxfd + 1, &listeners, NULL, NULL, NULL) == -1) { /* Don't choke when we get ptraced */ if (errno == EINTR) continue; logmsg(LOG_ERR, "select: %m"); goto rarpd_loop_err; } for (ii = iflist; ii != NULL; ii = ii->ii_next) { fd = ii->ii_fd; if (!FD_ISSET(fd, &listeners)) continue; again: cc = read(fd, (char *)buf, bufsize); /* Don't choke when we get ptraced */ if ((cc == -1) && (errno == EINTR)) goto again; /* Loop through the packet(s) */ #define bhp ((struct bpf_hdr *)bp) bp = buf; ep = bp + cc; while (bp < ep) { u_int caplen, hdrlen; caplen = bhp->bh_caplen; hdrlen = bhp->bh_hdrlen; if (rarp_check(bp + hdrlen, caplen)) rarp_process(ii, bp + hdrlen, caplen); bp += BPF_WORDALIGN(hdrlen + caplen); } } } #undef bhp return; rarpd_loop_err: pidfile_remove(pidfile_fh); exit(1); } /* * True if this server can boot the host whose IP address is 'addr'. * This check is made by looking in the tftp directory for the * configuration file. */ static int rarp_bootable(in_addr_t addr) { struct dirent *dent; DIR *d; char ipname[9]; static DIR *dd = NULL; (void)sprintf(ipname, "%08X", (in_addr_t)ntohl(addr)); /* * If directory is already open, rewind it. Otherwise, open it. */ if ((d = dd) != NULL) rewinddir(d); else { if (chdir(tftp_dir) == -1) { logmsg(LOG_ERR, "chdir: %s: %m", tftp_dir); goto rarp_bootable_err; } d = opendir("."); if (d == NULL) { logmsg(LOG_ERR, "opendir: %m"); goto rarp_bootable_err; } dd = d; } while ((dent = readdir(d)) != NULL) if (strncmp(dent->d_name, ipname, 8) == 0) return 1; return 0; rarp_bootable_err: pidfile_remove(pidfile_fh); exit(1); } /* * Given a list of IP addresses, 'alist', return the first address that * is on network 'net'; 'netmask' is a mask indicating the network portion * of the address. */ static in_addr_t choose_ipaddr(in_addr_t **alist, in_addr_t net, in_addr_t netmask) { for (; *alist; ++alist) if ((**alist & netmask) == net) return **alist; return 0; } /* * Answer the RARP request in 'pkt', on the interface 'ii'. 'pkt' has * already been checked for validity. The reply is overlaid on the request. */ static void rarp_process(struct if_info *ii, u_char *pkt, u_int len) { struct ether_header *ep; struct hostent *hp; in_addr_t target_ipaddr; char ename[256]; ep = (struct ether_header *)pkt; /* should this be arp_tha? */ if (ether_ntohost(ename, (struct ether_addr *)&ep->ether_shost) != 0) { logmsg(LOG_ERR, "cannot map %s to name", eatoa(ep->ether_shost)); return; } if ((hp = gethostbyname(ename)) == NULL) { logmsg(LOG_ERR, "cannot map %s to IP address", ename); return; } /* * Choose correct address from list. */ if (hp->h_addrtype != AF_INET) { logmsg(LOG_ERR, "cannot handle non IP addresses for %s", ename); return; } target_ipaddr = choose_ipaddr((in_addr_t **)hp->h_addr_list, ii->ii_ipaddr & ii->ii_netmask, ii->ii_netmask); if (target_ipaddr == 0) { logmsg(LOG_ERR, "cannot find %s on net %s", ename, intoa(ntohl(ii->ii_ipaddr & ii->ii_netmask))); return; } if (sflag || rarp_bootable(target_ipaddr)) rarp_reply(ii, ep, target_ipaddr, len); else if (verbose > 1) logmsg(LOG_INFO, "%s %s at %s DENIED (not bootable)", ii->ii_ifname, eatoa(ep->ether_shost), intoa(ntohl(target_ipaddr))); } /* * Poke the kernel arp tables with the ethernet/ip address combinataion * given. When processing a reply, we must do this so that the booting * host (i.e. the guy running rarpd), won't try to ARP for the hardware * address of the guy being booted (he cannot answer the ARP). */ static struct sockaddr_in sin_inarp = { sizeof(struct sockaddr_in), AF_INET, 0, {0}, {0}, }; static struct sockaddr_dl sin_dl = { sizeof(struct sockaddr_dl), AF_LINK, 0, IFT_ETHER, 0, 6, 0, "" }; static struct { struct rt_msghdr rthdr; char rtspace[512]; } rtmsg; static void update_arptab(u_char *ep, in_addr_t ipaddr) { struct timespec tp; int cc; struct sockaddr_in *ar, *ar2; struct sockaddr_dl *ll, *ll2; struct rt_msghdr *rt; int xtype, xindex; static pid_t pid; int r; static int seq; r = socket(PF_ROUTE, SOCK_RAW, 0); if (r == -1) { logmsg(LOG_ERR, "raw route socket: %m"); pidfile_remove(pidfile_fh); exit(1); } pid = getpid(); ar = &sin_inarp; ar->sin_addr.s_addr = ipaddr; ll = &sin_dl; bcopy(ep, LLADDR(ll), 6); /* Get the type and interface index */ rt = &rtmsg.rthdr; bzero(rt, sizeof(rtmsg)); rt->rtm_version = RTM_VERSION; rt->rtm_addrs = RTA_DST; rt->rtm_type = RTM_GET; rt->rtm_seq = ++seq; ar2 = (struct sockaddr_in *)rtmsg.rtspace; bcopy(ar, ar2, sizeof(*ar)); rt->rtm_msglen = sizeof(*rt) + sizeof(*ar); errno = 0; if ((write(r, rt, rt->rtm_msglen) == -1) && (errno != ESRCH)) { logmsg(LOG_ERR, "rtmsg get write: %m"); close(r); return; } do { cc = read(r, rt, sizeof(rtmsg)); } while (cc > 0 && (rt->rtm_seq != seq || rt->rtm_pid != pid)); if (cc == -1) { logmsg(LOG_ERR, "rtmsg get read: %m"); close(r); return; } ll2 = (struct sockaddr_dl *)((u_char *)ar2 + ar2->sin_len); if (ll2->sdl_family != AF_LINK) { /* * XXX I think this means the ip address is not on a * directly connected network (the family is AF_INET in * this case). */ logmsg(LOG_ERR, "bogus link family (%d) wrong net for %08X?\n", ll2->sdl_family, ipaddr); close(r); return; } xtype = ll2->sdl_type; xindex = ll2->sdl_index; /* Set the new arp entry */ bzero(rt, sizeof(rtmsg)); rt->rtm_version = RTM_VERSION; rt->rtm_addrs = RTA_DST | RTA_GATEWAY; rt->rtm_inits = RTV_EXPIRE; clock_gettime(CLOCK_MONOTONIC, &tp); rt->rtm_rmx.rmx_expire = tp.tv_sec + ARPSECS; rt->rtm_flags = RTF_HOST | RTF_STATIC; rt->rtm_type = RTM_ADD; rt->rtm_seq = ++seq; bcopy(ar, ar2, sizeof(*ar)); ll2 = (struct sockaddr_dl *)((u_char *)ar2 + sizeof(*ar2)); bcopy(ll, ll2, sizeof(*ll)); ll2->sdl_type = xtype; ll2->sdl_index = xindex; rt->rtm_msglen = sizeof(*rt) + sizeof(*ar2) + sizeof(*ll2); errno = 0; if ((write(r, rt, rt->rtm_msglen) == -1) && (errno != EEXIST)) { logmsg(LOG_ERR, "rtmsg add write: %m"); close(r); return; } do { cc = read(r, rt, sizeof(rtmsg)); } while (cc > 0 && (rt->rtm_seq != seq || rt->rtm_pid != pid)); close(r); if (cc == -1) { logmsg(LOG_ERR, "rtmsg add read: %m"); return; } } /* * Build a reverse ARP packet and sent it out on the interface. * 'ep' points to a valid REVARP_REQUEST. The REVARP_REPLY is built * on top of the request, then written to the network. * * RFC 903 defines the ether_arp fields as follows. The following comments * are taken (more or less) straight from this document. * * REVARP_REQUEST * * arp_sha is the hardware address of the sender of the packet. * arp_spa is undefined. * arp_tha is the 'target' hardware address. * In the case where the sender wishes to determine his own * protocol address, this, like arp_sha, will be the hardware * address of the sender. * arp_tpa is undefined. * * REVARP_REPLY * * arp_sha is the hardware address of the responder (the sender of the * reply packet). * arp_spa is the protocol address of the responder (see the note below). * arp_tha is the hardware address of the target, and should be the same as * that which was given in the request. * arp_tpa is the protocol address of the target, that is, the desired address. * * Note that the requirement that arp_spa be filled in with the responder's * protocol is purely for convenience. For instance, if a system were to use * both ARP and RARP, then the inclusion of the valid protocol-hardware * address pair (arp_spa, arp_sha) may eliminate the need for a subsequent * ARP request. */ static void rarp_reply(struct if_info *ii, struct ether_header *ep, in_addr_t ipaddr, u_int len) { u_int n; struct ether_arp *ap = (struct ether_arp *)(ep + 1); update_arptab((u_char *)&ap->arp_sha, ipaddr); /* * Build the rarp reply by modifying the rarp request in place. */ ap->arp_op = htons(REVARP_REPLY); #ifdef BROKEN_BPF ep->ether_type = ETHERTYPE_REVARP; #endif bcopy((char *)&ap->arp_sha, (char *)&ep->ether_dhost, 6); bcopy((char *)ii->ii_eaddr, (char *)&ep->ether_shost, 6); bcopy((char *)ii->ii_eaddr, (char *)&ap->arp_sha, 6); bcopy((char *)&ipaddr, (char *)ap->arp_tpa, 4); /* Target hardware is unchanged. */ bcopy((char *)&ii->ii_ipaddr, (char *)ap->arp_spa, 4); /* Zero possible garbage after packet. */ bzero((char *)ep + (sizeof(*ep) + sizeof(*ap)), len - (sizeof(*ep) + sizeof(*ap))); n = write(ii->ii_fd, (char *)ep, len); if (n != len) logmsg(LOG_ERR, "write: only %d of %d bytes written", n, len); if (verbose) logmsg(LOG_INFO, "%s %s at %s REPLIED", ii->ii_ifname, eatoa(ap->arp_tha), intoa(ntohl(ipaddr))); } /* * Get the netmask of an IP address. This routine is used if * SIOCGIFNETMASK doesn't work. */ static in_addr_t ipaddrtonetmask(in_addr_t addr) { addr = ntohl(addr); if (IN_CLASSA(addr)) return htonl(IN_CLASSA_NET); if (IN_CLASSB(addr)) return htonl(IN_CLASSB_NET); if (IN_CLASSC(addr)) return htonl(IN_CLASSC_NET); logmsg(LOG_DEBUG, "unknown IP address class: %08X", addr); return htonl(0xffffffff); } /* * A faster replacement for inet_ntoa(). */ static char * intoa(in_addr_t addr) { char *cp; u_int byte; int n; static char buf[sizeof(".xxx.xxx.xxx.xxx")]; cp = &buf[sizeof buf]; *--cp = '\0'; n = 4; do { byte = addr & 0xff; *--cp = byte % 10 + '0'; byte /= 10; if (byte > 0) { *--cp = byte % 10 + '0'; byte /= 10; if (byte > 0) *--cp = byte + '0'; } *--cp = '.'; addr >>= 8; } while (--n > 0); return cp + 1; } static char * eatoa(u_char *ea) { static char buf[sizeof("xx:xx:xx:xx:xx:xx")]; (void)sprintf(buf, "%x:%x:%x:%x:%x:%x", ea[0], ea[1], ea[2], ea[3], ea[4], ea[5]); return (buf); } static void logmsg(int pri, const char *fmt, ...) { va_list v; FILE *fp; char *newfmt; va_start(v, fmt); if (dflag) { if (pri == LOG_ERR) fp = stderr; else fp = stdout; if (expand_syslog_m(fmt, &newfmt) == -1) { vfprintf(fp, fmt, v); } else { vfprintf(fp, newfmt, v); free(newfmt); } fputs("\n", fp); fflush(fp); } else { vsyslog(pri, fmt, v); } va_end(v); } static int expand_syslog_m(const char *fmt, char **newfmt) { const char *str, *m; char *p, *np; p = strdup(""); str = fmt; while ((m = strstr(str, "%m")) != NULL) { asprintf(&np, "%s%.*s%s", p, (int)(m - str), str, strerror(errno)); free(p); if (np == NULL) { errno = ENOMEM; return (-1); } p = np; str = m + 2; } if (*str != '\0') { asprintf(&np, "%s%s", p, str); free(p); if (np == NULL) { errno = ENOMEM; return (-1); } p = np; } *newfmt = p; return (0); }