/* $OpenBSD: dhclient.c,v 1.141 2011/05/11 14:38:36 krw Exp $ */ /* * Copyright 2004 Henning Brauer * Copyright (c) 1995, 1996, 1997, 1998, 1999 * The Internet Software Consortium. 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. Neither the name of The Internet Software Consortium 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 INTERNET SOFTWARE CONSORTIUM 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 INTERNET SOFTWARE CONSORTIUM 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. * * This software has been written for the Internet Software Consortium * by Ted Lemon in cooperation with Vixie * Enterprises. To learn more about the Internet Software Consortium, * see ``http://www.vix.com/isc''. To learn more about Vixie * Enterprises, see ``http://www.vix.com''. * * This client was substantially modified and enhanced by Elliot Poger * for use on Linux while he was working on the MosquitoNet project at * Stanford. * * The current version owes much to Elliot's Linux enhancements, but * was substantially reorganized and partially rewritten by Ted Lemon * so as to use the same networking framework that the Internet Software * Consortium DHCP server uses. Much system-specific configuration code * was moved into a shell script so that as support for more operating * systems is added, it will not be necessary to port and maintain * system-specific configuration code to these operating systems - instead, * the shell script can invoke the native tools to accomplish the same * purpose. */ #include #include #include #include #include "dhcpd.h" #include "privsep.h" #define CLIENT_PATH "PATH=/usr/bin:/usr/sbin:/bin:/sbin" #define DEFAULT_LEASE_TIME 43200 /* 12 hours... */ #define TIME_MAX 2147483647 time_t cur_time; char *path_dhclient_conf = _PATH_DHCLIENT_CONF; char *path_dhclient_db = NULL; int log_perror = 1; int privfd; int nullfd = -1; int no_daemon; int unknown_ok = 1; int routefd = -1; struct iaddr iaddr_broadcast = { 4, { 255, 255, 255, 255 } }; struct in_addr inaddr_any; struct sockaddr_in sockaddr_broadcast; struct interface_info *ifi; struct client_state *client; struct client_config *config; int findproto(char *, int); struct sockaddr *get_ifa(char *, int); void usage(void); int check_option(struct client_lease *l, int option); int ipv4addrs(char * buf); int res_hnok(const char *dn); char *option_as_string(unsigned int code, unsigned char *data, int len); int fork_privchld(int, int); void get_ifname(char *, char *); #define ROUNDUP(a) \ ((a) > 0 ? (1 + (((a) - 1) | (sizeof(long) - 1))) : sizeof(long)) #define ADVANCE(x, n) (x += ROUNDUP((n)->sa_len)) time_t scripttime; static FILE *leaseFile; int findproto(char *cp, int n) { struct sockaddr *sa; int i; if (n == 0) return -1; for (i = 1; i; i <<= 1) { if (i & n) { sa = (struct sockaddr *)cp; switch (i) { case RTA_IFA: case RTA_DST: case RTA_GATEWAY: case RTA_NETMASK: if (sa->sa_family == AF_INET) return AF_INET; if (sa->sa_family == AF_INET6) return AF_INET6; break; case RTA_IFP: break; } ADVANCE(cp, sa); } } return (-1); } struct sockaddr * get_ifa(char *cp, int n) { struct sockaddr *sa; int i; if (n == 0) return (NULL); for (i = 1; i; i <<= 1) if (i & n) { sa = (struct sockaddr *)cp; if (i == RTA_IFA) return (sa); ADVANCE(cp, sa); } return (NULL); } struct iaddr defaddr = { 4 }; void routehandler(void) { int linkstat; char msg[2048]; struct rt_msghdr *rtm; struct if_msghdr *ifm; struct ifa_msghdr *ifam; struct if_announcemsghdr *ifan; struct client_lease *l; time_t t = time(NULL); struct sockaddr *sa; struct iaddr a; ssize_t n; char *errmsg, buf[64]; do { n = read(routefd, &msg, sizeof(msg)); } while (n == -1 && errno == EINTR); rtm = (struct rt_msghdr *)msg; if (n < sizeof(rtm->rtm_msglen) || n < rtm->rtm_msglen || rtm->rtm_version != RTM_VERSION) return; switch (rtm->rtm_type) { case RTM_NEWADDR: ifam = (struct ifa_msghdr *)rtm; if (ifam->ifam_index != ifi->index) break; if (findproto((char *)ifam + ifam->ifam_hdrlen, ifam->ifam_addrs) != AF_INET) break; sa = get_ifa((char *)ifam + ifam->ifam_hdrlen, ifam->ifam_addrs); if (sa == NULL) { errmsg = "sa == NULL"; goto die; } if ((a.len = sizeof(struct in_addr)) > sizeof(a.iabuf)) error("king bula sez: len mismatch"); memcpy(a.iabuf, &((struct sockaddr_in *)sa)->sin_addr, a.len); if (addr_eq(a, defaddr)) break; /* state_panic() can try unexpired existing leases */ if (client->active && addr_eq(a, client->active->address)) break; for (l = client->leases; l != NULL; l = l->next) if (addr_eq(a, l->address)) break; if (l != NULL) /* new addr is the one we set */ break; snprintf(buf, sizeof(buf), "%s: %s", "new address not one we set", piaddr(a)); errmsg = buf; goto die; case RTM_DELADDR: ifam = (struct ifa_msghdr *)rtm; if (ifam->ifam_index != ifi->index) break; if (findproto((char *)ifam + ifam->ifam_hdrlen, ifam->ifam_addrs) != AF_INET) break; /* XXX check addrs like RTM_NEWADDR instead of this? */ if (scripttime == 0 || t < scripttime + 10) break; errmsg = "interface address deleted"; goto die; case RTM_IFINFO: ifm = (struct if_msghdr *)rtm; if (ifm->ifm_index != ifi->index) break; if ((rtm->rtm_flags & RTF_UP) == 0) { errmsg = "interface down"; goto die; } linkstat = LINK_STATE_IS_UP(ifm->ifm_data.ifi_link_state) ? 1 : 0; if (linkstat != ifi->linkstat) { #ifdef DEBUG debug("link state %s -> %s", ifi->linkstat ? "up" : "down", linkstat ? "up" : "down"); #endif ifi->linkstat = interface_link_status(ifi->name); if (ifi->linkstat) { client->state = S_INIT; state_reboot(); } } break; case RTM_IFANNOUNCE: ifan = (struct if_announcemsghdr *)rtm; if (ifan->ifan_what == IFAN_DEPARTURE && ifan->ifan_index == ifi->index) { errmsg = "interface departure"; goto die; } break; default: break; } return; die: script_init("FAIL"); script_go(); error("routehandler: %s", errmsg); } int main(int argc, char *argv[]) { int ch, fd, quiet = 0, i = 0, pipe_fd[2]; extern char *__progname; struct passwd *pw; int rtfilter; /* Initially, log errors to stderr as well as to syslogd. */ openlog(__progname, LOG_PID | LOG_NDELAY, DHCPD_LOG_FACILITY); setlogmask(LOG_UPTO(LOG_INFO)); while ((ch = getopt(argc, argv, "c:dl:qu")) != -1) switch (ch) { case 'c': path_dhclient_conf = optarg; break; case 'd': no_daemon = 1; break; case 'l': path_dhclient_db = optarg; break; case 'q': quiet = 1; break; case 'u': unknown_ok = 0; break; default: usage(); } argc -= optind; argv += optind; if (argc != 1) usage(); ifi = calloc(1, sizeof(*ifi)); if (ifi == NULL) error("ifi calloc"); client = calloc(1, sizeof(*client)); if (client == NULL) error("client calloc"); config = calloc(1, sizeof(*config)); if (config == NULL) error("config calloc"); get_ifname(ifi->name, argv[0]); if (path_dhclient_db == NULL && asprintf(&path_dhclient_db, "%s.%s", _PATH_DHCLIENT_DB, ifi->name) == -1) error("asprintf"); if (quiet) log_perror = 0; tzset(); time(&cur_time); memset(&sockaddr_broadcast, 0, sizeof(sockaddr_broadcast)); sockaddr_broadcast.sin_family = AF_INET; sockaddr_broadcast.sin_port = htons(REMOTE_PORT); sockaddr_broadcast.sin_addr.s_addr = INADDR_BROADCAST; sockaddr_broadcast.sin_len = sizeof(sockaddr_broadcast); inaddr_any.s_addr = INADDR_ANY; /* Put us into the correct rdomain */ ifi->rdomain = get_rdomain(ifi->name); read_client_conf(); if (interface_status(ifi->name) == 0) { interface_link_forceup(ifi->name); /* Give it up to 4 seconds of silent grace to find link */ i = -4; } else i = 0; while (!(ifi->linkstat = interface_link_status(ifi->name))) { if (i == 0) fprintf(stderr, "%s: no link ...", ifi->name); else if (i > 0) fprintf(stderr, "."); fflush(stderr); if (++i > config->link_timeout) { fprintf(stderr, " sleeping\n"); goto dispatch; } sleep(1); } if (i > 0) fprintf(stderr, " got link\n"); dispatch: if ((nullfd = open(_PATH_DEVNULL, O_RDWR, 0)) == -1) error("cannot open %s: %m", _PATH_DEVNULL); if ((pw = getpwnam("_dhcp")) == NULL) error("no such user: _dhcp"); if (pipe(pipe_fd) == -1) error("pipe"); fork_privchld(pipe_fd[0], pipe_fd[1]); close(pipe_fd[0]); privfd = pipe_fd[1]; if ((fd = open(path_dhclient_db, O_RDONLY|O_EXLOCK|O_CREAT, 0)) == -1) error("can't open and lock %s: %m", path_dhclient_db); read_client_leases(); if ((leaseFile = fopen(path_dhclient_db, "w")) == NULL) error("can't open %s: %m", path_dhclient_db); rewrite_client_leases(); close(fd); if ((routefd = socket(PF_ROUTE, SOCK_RAW, 0)) == -1) error("socket(PF_ROUTE, SOCK_RAW): %m"); rtfilter = ROUTE_FILTER(RTM_NEWADDR) | ROUTE_FILTER(RTM_DELADDR) | ROUTE_FILTER(RTM_IFINFO) | ROUTE_FILTER(RTM_IFANNOUNCE); if (setsockopt(routefd, PF_ROUTE, ROUTE_MSGFILTER, &rtfilter, sizeof(rtfilter)) == -1) error("setsockopt(ROUTE_MSGFILTER): %m"); /* set up the interface */ discover_interface(); if (chroot(_PATH_VAREMPTY) == -1) error("chroot"); if (chdir("/") == -1) error("chdir(\"/\")"); if (setresgid(pw->pw_gid, pw->pw_gid, pw->pw_gid) == -1) error("setresgid"); if (setgroups(1, &pw->pw_gid) == -1) error("setgroups"); if (setresuid(pw->pw_uid, pw->pw_uid, pw->pw_uid) == -1) error("setresuid"); endpwent(); setproctitle("%s", ifi->name); if (ifi->linkstat) { client->state = S_INIT; state_reboot(); } else go_daemon(); dispatch(); /* not reached */ return (0); } void usage(void) { extern char *__progname; fprintf(stderr, "usage: %s [-dqu] [-c file] [-l file] interface\n", __progname); exit(1); } /* * Individual States: * * Each routine is called from the dhclient_state_machine() in one of * these conditions: * -> entering INIT state * -> recvpacket_flag == 0: timeout in this state * -> otherwise: received a packet in this state * * Return conditions as handled by dhclient_state_machine(): * Returns 1, sendpacket_flag = 1: send packet, reset timer. * Returns 1, sendpacket_flag = 0: just reset the timer (wait for a milestone). * Returns 0: finish the nap which was interrupted for no good reason. * * Several per-interface variables are used to keep track of the process: * active_lease: the lease that is being used on the interface * (null pointer if not configured yet). * offered_leases: leases corresponding to DHCPOFFER messages that have * been sent to us by DHCP servers. * acked_leases: leases corresponding to DHCPACK messages that have been * sent to us by DHCP servers. * sendpacket: DHCP packet we're trying to send. * destination: IP address to send sendpacket to * In addition, there are several relevant per-lease variables. * T1_expiry, T2_expiry, lease_expiry: lease milestones * In the active lease, these control the process of renewing the lease; * In leases on the acked_leases list, this simply determines when we * can no longer legitimately use the lease. */ void state_reboot(void) { /* If we don't remember an active lease, go straight to INIT. */ if (!client->active || client->active->is_bootp) { state_init(); return; } /* We are in the rebooting state. */ client->state = S_REBOOTING; /* make_request doesn't initialize xid because it normally comes from the DHCPDISCOVER, but we haven't sent a DHCPDISCOVER, so pick an xid now. */ client->xid = arc4random(); /* Make a DHCPREQUEST packet, and set appropriate per-interface flags. */ make_request(client->active); client->destination = iaddr_broadcast; client->first_sending = cur_time; client->interval = 0; /* Send out the first DHCPREQUEST packet. */ send_request(); } /* * Called when a lease has completely expired and we've * been unable to renew it. */ void state_init(void) { /* Make a DHCPDISCOVER packet, and set appropriate per-interface flags. */ make_discover(client->active); client->xid = client->packet.xid; client->destination = iaddr_broadcast; client->state = S_SELECTING; client->first_sending = cur_time; client->interval = 0; /* Add an immediate timeout to cause the first DHCPDISCOVER packet to go out. */ send_discover(); } /* * state_selecting is called when one or more DHCPOFFER packets * have been received and a configurable period of time has passed. */ void state_selecting(void) { struct client_lease *lp, *next, *picked; /* Cancel state_selecting and send_discover timeouts, since either one could have got us here. */ cancel_timeout(state_selecting); cancel_timeout(send_discover); /* We have received one or more DHCPOFFER packets. Currently, the only criterion by which we judge leases is whether or not we get a response when we arp for them. */ picked = NULL; for (lp = client->offered_leases; lp; lp = next) { next = lp->next; if (!picked) { picked = lp; } else { make_decline(lp); send_decline(); free_client_lease(lp); } } client->offered_leases = NULL; /* If we just tossed all the leases we were offered, go back to square one. */ if (!picked) { client->state = S_INIT; state_init(); return; } picked->next = NULL; /* If it was a BOOTREPLY, we can just take the address right now. */ if (!picked->options[DHO_DHCP_MESSAGE_TYPE].len) { client->new = picked; /* Make up some lease expiry times XXX these should be configurable. */ client->new->expiry = cur_time + 12000; client->new->renewal += cur_time + 8000; client->new->rebind += cur_time + 10000; client->state = S_REQUESTING; /* Bind to the address we received. */ bind_lease(); return; } /* Go to the REQUESTING state. */ client->destination = iaddr_broadcast; client->state = S_REQUESTING; client->first_sending = cur_time; client->interval = 0; /* Make a DHCPREQUEST packet from the lease we picked. */ make_request(picked); client->xid = client->packet.xid; /* Toss the lease we picked - we'll get it back in a DHCPACK. */ free_client_lease(picked); /* Add an immediate timeout to send the first DHCPREQUEST packet. */ send_request(); } void dhcpack(struct iaddr client_addr, struct option_data *options) { struct client_lease *lease; if (client->state != S_REBOOTING && client->state != S_REQUESTING && client->state != S_RENEWING && client->state != S_REBINDING) return; lease = packet_to_lease(client_addr, options); if (!lease) { note("packet_to_lease failed."); return; } client->new = lease; /* Stop resending DHCPREQUEST. */ cancel_timeout(send_request); /* Figure out the lease time. */ if (client->new->options[DHO_DHCP_LEASE_TIME].data) client->new->expiry = getULong(client->new->options[DHO_DHCP_LEASE_TIME].data); else client->new->expiry = DEFAULT_LEASE_TIME; /* A number that looks negative here is really just very large, because the lease expiry offset is unsigned. */ if (client->new->expiry < 0) client->new->expiry = TIME_MAX; /* XXX should be fixed by resetting the client state */ if (client->new->expiry < 60) client->new->expiry = 60; /* Take the server-provided renewal time if there is one; otherwise figure it out according to the spec. */ if (client->new->options[DHO_DHCP_RENEWAL_TIME].len) client->new->renewal = getULong(client->new->options[DHO_DHCP_RENEWAL_TIME].data); else client->new->renewal = client->new->expiry / 2; /* Same deal with the rebind time. */ if (client->new->options[DHO_DHCP_REBINDING_TIME].len) client->new->rebind = getULong(client->new->options[DHO_DHCP_REBINDING_TIME].data); else client->new->rebind = client->new->renewal + client->new->renewal / 2 + client->new->renewal / 4; client->new->expiry += cur_time; /* Lease lengths can never be negative. */ if (client->new->expiry < cur_time) client->new->expiry = TIME_MAX; client->new->renewal += cur_time; if (client->new->renewal < cur_time) client->new->renewal = TIME_MAX; client->new->rebind += cur_time; if (client->new->rebind < cur_time) client->new->rebind = TIME_MAX; bind_lease(); } void bind_lease(void) { /* Write out the new lease. */ write_client_lease(client->new, 0); /* Run the client script with the new parameters. */ script_init((client->state == S_REQUESTING ? "BOUND" : (client->state == S_RENEWING ? "RENEW" : (client->state == S_REBOOTING ? "REBOOT" : "REBIND")))); if (client->active && client->state != S_REBOOTING) script_write_params("old_", client->active); script_write_params("new_", client->new); script_go(); /* Replace the old active lease with the new one. */ if (client->active) free_client_lease(client->active); client->active = client->new; client->new = NULL; /* Set up a timeout to start the renewal process. */ add_timeout(client->active->renewal, state_bound); note("bound to %s -- renewal in %d seconds.", piaddr(client->active->address), client->active->renewal - cur_time); client->state = S_BOUND; reinitialize_interface(); go_daemon(); } /* * state_bound is called when we've successfully bound to a particular * lease, but the renewal time on that lease has expired. We are * expected to unicast a DHCPREQUEST to the server that gave us our * original lease. */ void state_bound(void) { /* T1 has expired. */ make_request(client->active); client->xid = client->packet.xid; if (client->active->options[DHO_DHCP_SERVER_IDENTIFIER].len == 4) { memcpy(client->destination.iabuf, client->active->options[DHO_DHCP_SERVER_IDENTIFIER].data, 4); client->destination.len = 4; } else client->destination = iaddr_broadcast; client->first_sending = cur_time; client->interval = 0; client->state = S_RENEWING; /* Send the first packet immediately. */ send_request(); } void dhcpoffer(struct iaddr client_addr, struct option_data *options) { struct client_lease *lease, *lp; int i; int stop_selecting; char *name = options[DHO_DHCP_MESSAGE_TYPE].len ? "DHCPOFFER" : "BOOTREPLY"; if (client->state != S_SELECTING) return; /* If this lease doesn't supply the minimum required parameters, blow it off. */ for (i = 0; config->required_options[i]; i++) { if (!options[config->required_options[i]].len) { note("%s isn't satisfactory.", name); return; } } /* If we've already seen this lease, don't record it again. */ for (lease = client->offered_leases; lease; lease = lease->next) { if (lease->address.len == sizeof(client->packet.yiaddr) && !memcmp(lease->address.iabuf, &client->packet.yiaddr, lease->address.len)) { #ifdef DEBUG debug("%s already seen.", name); #endif return; } } lease = packet_to_lease(client_addr, options); if (!lease) { note("packet_to_lease failed."); return; } /* If this lease was acquired through a BOOTREPLY, record that fact. */ if (!options[DHO_DHCP_MESSAGE_TYPE].len) lease->is_bootp = 1; /* Figure out when we're supposed to stop selecting. */ stop_selecting = client->first_sending + config->select_interval; /* If this is the lease we asked for, put it at the head of the list, and don't mess with the arp request timeout. */ if (addr_eq(lease->address, client->requested_address)) { lease->next = client->offered_leases; client->offered_leases = lease; } else { /* Put the lease at the end of the list. */ lease->next = NULL; if (!client->offered_leases) client->offered_leases = lease; else { for (lp = client->offered_leases; lp->next; lp = lp->next) ; /* nothing */ lp->next = lease; } } /* If the selecting interval has expired, go immediately to state_selecting(). Otherwise, time out into state_selecting at the select interval. */ if (stop_selecting <= cur_time) state_selecting(); else { add_timeout(stop_selecting, state_selecting); cancel_timeout(send_discover); } } /* * Allocate a client_lease structure and initialize it from the * parameters in the specified packet. */ struct client_lease * packet_to_lease(struct iaddr client_addr, struct option_data *options) { struct client_lease *lease; int i; lease = malloc(sizeof(struct client_lease)); if (!lease) { warning("dhcpoffer: no memory to record lease."); return (NULL); } memset(lease, 0, sizeof(*lease)); /* Copy the lease options. */ for (i = 0; i < 256; i++) { if (options[i].len) { lease->options[i] = options[i]; options[i].data = NULL; options[i].len = 0; if (!check_option(lease, i)) { warning("Invalid lease option - ignoring offer"); free_client_lease(lease); return (NULL); } } } lease->address.len = sizeof(client->packet.yiaddr); memcpy(lease->address.iabuf, &client->packet.yiaddr, lease->address.len); /* If the server name was filled out, copy it. */ if ((!lease->options[DHO_DHCP_OPTION_OVERLOAD].len || !(lease->options[DHO_DHCP_OPTION_OVERLOAD].data[0] & 2)) && client->packet.sname[0]) { lease->server_name = malloc(DHCP_SNAME_LEN + 1); if (!lease->server_name) { warning("dhcpoffer: no memory for server name."); free_client_lease(lease); return (NULL); } memcpy(lease->server_name, client->packet.sname, DHCP_SNAME_LEN); lease->server_name[DHCP_SNAME_LEN] = '\0'; if (!res_hnok(lease->server_name)) { warning("Bogus server name %s", lease->server_name); free(lease->server_name); lease->server_name = NULL; } } /* Ditto for the filename. */ if ((!lease->options[DHO_DHCP_OPTION_OVERLOAD].len || !(lease->options[DHO_DHCP_OPTION_OVERLOAD].data[0] & 1)) && client->packet.file[0]) { /* Don't count on the NUL terminator. */ lease->filename = malloc(DHCP_FILE_LEN + 1); if (!lease->filename) { warning("dhcpoffer: no memory for filename."); free_client_lease(lease); return (NULL); } memcpy(lease->filename, client->packet.file, DHCP_FILE_LEN); lease->filename[DHCP_FILE_LEN] = '\0'; } return lease; } void dhcpnak(struct iaddr client_addr, struct option_data *options) { if (client->state != S_REBOOTING && client->state != S_REQUESTING && client->state != S_RENEWING && client->state != S_REBINDING) return; if (!client->active) { note("DHCPNAK with no active lease."); return; } free_client_lease(client->active); client->active = NULL; /* Stop sending DHCPREQUEST packets... */ cancel_timeout(send_request); client->state = S_INIT; state_init(); } /* * Send out a DHCPDISCOVER packet, and set a timeout to send out another * one after the right interval has expired. If we don't get an offer by * the time we reach the panic interval, call the panic function. */ void send_discover(void) { int interval, increase = 1; /* Figure out how long it's been since we started transmitting. */ interval = cur_time - client->first_sending; /* If we're past the panic timeout, call the script and tell it we haven't found anything for this interface yet. */ if (interval > config->timeout) { state_panic(); return; } /* * If we're supposed to increase the interval, do so. If it's * currently zero (i.e., we haven't sent any packets yet), set * it to initial_interval; otherwise, add to it a random * number between zero and two times itself. On average, this * means that it will double with every transmission. */ if (increase) { if (!client->interval) client->interval = config->initial_interval; else { client->interval += (arc4random() >> 2) % (2 * client->interval); } /* Don't backoff past cutoff. */ if (client->interval > config->backoff_cutoff) client->interval = ((config->backoff_cutoff / 2) + ((arc4random() >> 2) % config->backoff_cutoff)); } else if (!client->interval) client->interval = config->initial_interval; /* If the backoff would take us to the panic timeout, just use that as the interval. */ if (cur_time + client->interval > client->first_sending + config->timeout) client->interval = (client->first_sending + config->timeout) - cur_time + 1; /* Record the number of seconds since we started sending. */ if (interval < 65536) client->packet.secs = htons(interval); else client->packet.secs = htons(65535); client->secs = client->packet.secs; note("DHCPDISCOVER on %s to %s port %d interval %d", ifi->name, inet_ntoa(sockaddr_broadcast.sin_addr), ntohs(sockaddr_broadcast.sin_port), client->interval); /* Send out a packet. */ send_packet(inaddr_any, &sockaddr_broadcast, NULL); add_timeout(cur_time + client->interval, send_discover); } /* * state_panic gets called if we haven't received any offers in a preset * amount of time. When this happens, we try to use existing leases * that haven't yet expired, and failing that, we call the client script * and hope it can do something. */ void state_panic(void) { struct client_lease *loop = client->active; struct client_lease *lp; note("No DHCPOFFERS received."); /* We may not have an active lease, but we may have some predefined leases that we can try. */ if (!client->active && client->leases) goto activate_next; /* Run through the list of leases and see if one can be used. */ while (client->active) { if (client->active->expiry > cur_time) { note("Trying recorded lease %s", piaddr(client->active->address)); /* Run the client script with the existing parameters. */ script_init("TIMEOUT"); script_write_params("new_", client->active); /* If the old lease is still good and doesn't yet need renewal, go into BOUND state and timeout at the renewal time. */ if (!script_go()) { if (cur_time < client->active->renewal) { client->state = S_BOUND; note("bound: renewal in %d seconds.", client->active->renewal - cur_time); add_timeout(client->active->renewal, state_bound); } else { client->state = S_BOUND; note("bound: immediate renewal."); state_bound(); } reinitialize_interface(); go_daemon(); return; } } /* If there are no other leases, give up. */ if (!client->leases) { client->leases = client->active; client->active = NULL; break; } activate_next: /* Otherwise, put the active lease at the end of the lease list, and try another lease.. */ for (lp = client->leases; lp->next; lp = lp->next) ; lp->next = client->active; if (lp->next) lp->next->next = NULL; client->active = client->leases; client->leases = client->leases->next; /* If we already tried this lease, we've exhausted the set of leases, so we might as well give up for now. */ if (client->active == loop) break; else if (!loop) loop = client->active; } /* No leases were available, or what was available didn't work, so tell the shell script that we failed to allocate an address, and try again later. */ note("No working leases in persistent database - sleeping."); script_init("FAIL"); script_go(); client->state = S_INIT; add_timeout(cur_time + config->retry_interval, state_init); go_daemon(); } void send_request(void) { struct sockaddr_in destination; struct in_addr from; int interval; /* Figure out how long it's been since we started transmitting. */ interval = cur_time - client->first_sending; /* If we're in the INIT-REBOOT or REQUESTING state and we're past the reboot timeout, go to INIT and see if we can DISCOVER an address... */ /* XXX In the INIT-REBOOT state, if we don't get an ACK, it means either that we're on a network with no DHCP server, or that our server is down. In the latter case, assuming that there is a backup DHCP server, DHCPDISCOVER will get us a new address, but we could also have successfully reused our old address. In the former case, we're hosed anyway. This is not a win-prone situation. */ if ((client->state == S_REBOOTING || client->state == S_REQUESTING) && interval > config->reboot_timeout) { client->state = S_INIT; cancel_timeout(send_request); state_init(); return; } /* If the lease has expired, relinquish the address and go back to the INIT state. */ if (client->state != S_REQUESTING && cur_time > client->active->expiry) { /* Run the client script with the new parameters. */ script_init("EXPIRE"); script_write_params("old_", client->active); script_go(); client->state = S_INIT; state_init(); return; } /* Do the exponential backoff... */ if (!client->interval) client->interval = config->initial_interval; else client->interval += ((arc4random() >> 2) % (2 * client->interval)); /* Don't backoff past cutoff. */ if (client->interval > config->backoff_cutoff) client->interval = ((config->backoff_cutoff / 2) + ((arc4random() >> 2) % client->interval)); /* If the backoff would take us to the expiry time, just set the timeout to the expiry time. */ if (client->state != S_REQUESTING && cur_time + client->interval > client->active->expiry) client->interval = client->active->expiry - cur_time + 1; /* If the lease T2 time has elapsed, or if we're not yet bound, broadcast the DHCPREQUEST rather than unicasting. */ memset(&destination, 0, sizeof(destination)); if (client->state == S_REQUESTING || client->state == S_REBOOTING || cur_time > client->active->rebind) destination.sin_addr.s_addr = INADDR_BROADCAST; else memcpy(&destination.sin_addr.s_addr, client->destination.iabuf, sizeof(destination.sin_addr.s_addr)); destination.sin_port = htons(REMOTE_PORT); destination.sin_family = AF_INET; destination.sin_len = sizeof(destination); if (client->state != S_REQUESTING) memcpy(&from, client->active->address.iabuf, sizeof(from)); else from.s_addr = INADDR_ANY; /* Record the number of seconds since we started sending. */ if (client->state == S_REQUESTING) client->packet.secs = client->secs; else { if (interval < 65536) client->packet.secs = htons(interval); else client->packet.secs = htons(65535); } note("DHCPREQUEST on %s to %s port %d", ifi->name, inet_ntoa(destination.sin_addr), ntohs(destination.sin_port)); /* Send out a packet. */ send_packet(from, &destination, NULL); add_timeout(cur_time + client->interval, send_request); } void send_decline(void) { note("DHCPDECLINE on %s to %s port %d", ifi->name, inet_ntoa(sockaddr_broadcast.sin_addr), ntohs(sockaddr_broadcast.sin_port)); /* Send out a packet. */ send_packet(inaddr_any, &sockaddr_broadcast, NULL); } void make_discover(struct client_lease *lease) { unsigned char discover = DHCPDISCOVER; struct option_data options[256]; int i; memset(options, 0, sizeof(options)); memset(&client->packet, 0, sizeof(client->packet)); /* Set DHCP_MESSAGE_TYPE to DHCPDISCOVER */ i = DHO_DHCP_MESSAGE_TYPE; options[i].data = &discover; options[i].len = sizeof(discover); /* Request the options we want */ i = DHO_DHCP_PARAMETER_REQUEST_LIST; options[i].data = config->requested_options; options[i].len = config->requested_option_count; /* If we had an address, try to get it again. */ if (lease) { client->requested_address = lease->address; i = DHO_DHCP_REQUESTED_ADDRESS; options[i].data = lease->address.iabuf; options[i].len = lease->address.len; } else client->requested_address.len = 0; /* Send any options requested in the config file. */ for (i = 0; i < 256; i++) if (!options[i].data && config->send_options[i].data) { options[i].data = config->send_options[i].data; options[i].len = config->send_options[i].len; } /* Set up the option buffer to fit in a minimal UDP packet. */ i = cons_options(options); if (i == -1 || client->packet.options[i] != DHO_END) error("options do not fit in DHCPDISCOVER packet."); client->packet_length = DHCP_FIXED_NON_UDP+i+1; if (client->packet_length < BOOTP_MIN_LEN) client->packet_length = BOOTP_MIN_LEN; client->packet.op = BOOTREQUEST; client->packet.htype = ifi->hw_address.htype; client->packet.hlen = ifi->hw_address.hlen; client->packet.hops = 0; client->packet.xid = arc4random(); client->packet.secs = 0; /* filled in by send_discover. */ client->packet.flags = 0; memset(&client->packet.ciaddr, 0, sizeof(client->packet.ciaddr)); memset(&client->packet.yiaddr, 0, sizeof(client->packet.yiaddr)); memset(&client->packet.siaddr, 0, sizeof(client->packet.siaddr)); memset(&client->packet.giaddr, 0, sizeof(client->packet.giaddr)); memcpy(client->packet.chaddr, ifi->hw_address.haddr, ifi->hw_address.hlen); } void make_request(struct client_lease * lease) { unsigned char request = DHCPREQUEST; struct option_data options[256]; int i; memset(options, 0, sizeof(options)); memset(&client->packet, 0, sizeof(client->packet)); /* Set DHCP_MESSAGE_TYPE to DHCPREQUEST */ i = DHO_DHCP_MESSAGE_TYPE; options[i].data = &request; options[i].len = sizeof(request); /* Request the options we want */ i = DHO_DHCP_PARAMETER_REQUEST_LIST; options[i].data = config->requested_options; options[i].len = config->requested_option_count; /* If we are requesting an address that hasn't yet been assigned to us, use the DHCP Requested Address option. */ if (client->state == S_REQUESTING) { /* Send back the server identifier... */ i = DHO_DHCP_SERVER_IDENTIFIER; options[i].data = lease->options[i].data; options[i].len = lease->options[i].len; } if (client->state == S_REQUESTING || client->state == S_REBOOTING) { client->requested_address = lease->address; i = DHO_DHCP_REQUESTED_ADDRESS; options[i].data = lease->address.iabuf; options[i].len = lease->address.len; } else client->requested_address.len = 0; /* Send any options requested in the config file. */ for (i = 0; i < 256; i++) if (!options[i].data && config->send_options[i].data) { options[i].data = config->send_options[i].data; options[i].len = config->send_options[i].len; } /* Set up the option buffer to fit in a minimal UDP packet. */ i = cons_options(options); if (i == -1 || client->packet.options[i] != DHO_END) error("options do not fit in DHCPREQUEST packet."); client->packet_length = DHCP_FIXED_NON_UDP+i+1; if (client->packet_length < BOOTP_MIN_LEN) client->packet_length = BOOTP_MIN_LEN; client->packet.op = BOOTREQUEST; client->packet.htype = ifi->hw_address.htype; client->packet.hlen = ifi->hw_address.hlen; client->packet.hops = 0; client->packet.xid = client->xid; client->packet.secs = 0; /* Filled in by send_request. */ client->packet.flags = 0; /* If we own the address we're requesting, put it in ciaddr; otherwise set ciaddr to zero. */ if (client->state == S_BOUND || client->state == S_RENEWING || client->state == S_REBINDING) { memcpy(&client->packet.ciaddr, lease->address.iabuf, lease->address.len); } else { memset(&client->packet.ciaddr, 0, sizeof(client->packet.ciaddr)); } memset(&client->packet.yiaddr, 0, sizeof(client->packet.yiaddr)); memset(&client->packet.siaddr, 0, sizeof(client->packet.siaddr)); memset(&client->packet.giaddr, 0, sizeof(client->packet.giaddr)); memcpy(client->packet.chaddr, ifi->hw_address.haddr, ifi->hw_address.hlen); } void make_decline(struct client_lease *lease) { struct option_data options[256]; unsigned char decline = DHCPDECLINE; int i; memset(options, 0, sizeof(options)); memset(&client->packet, 0, sizeof(client->packet)); /* Set DHCP_MESSAGE_TYPE to DHCPDECLINE */ i = DHO_DHCP_MESSAGE_TYPE; options[i].data = &decline; options[i].len = sizeof(decline); /* Send back the server identifier... */ i = DHO_DHCP_SERVER_IDENTIFIER; options[i].data = lease->options[i].data; options[i].len = lease->options[i].len; /* Send back the address we're declining. */ i = DHO_DHCP_REQUESTED_ADDRESS; options[i].data = lease->address.iabuf; options[i].len = lease->address.len; /* Send the uid if the user supplied one. */ i = DHO_DHCP_CLIENT_IDENTIFIER; if (config->send_options[i].len) { options[i].data = config->send_options[i].data; options[i].len = config->send_options[i].len; } /* Set up the option buffer to fit in a minimal UDP packet. */ i = cons_options(options); if (i == -1 || client->packet.options[i] != DHO_END) error("options do not fit in DHCPDECLINE packet."); client->packet_length = DHCP_FIXED_NON_UDP+i+1; if (client->packet_length < BOOTP_MIN_LEN) client->packet_length = BOOTP_MIN_LEN; client->packet.op = BOOTREQUEST; client->packet.htype = ifi->hw_address.htype; client->packet.hlen = ifi->hw_address.hlen; client->packet.hops = 0; client->packet.xid = client->xid; client->packet.secs = 0; /* Filled in by send_request. */ client->packet.flags = 0; /* ciaddr must always be zero. */ memset(&client->packet.ciaddr, 0, sizeof(client->packet.ciaddr)); memset(&client->packet.yiaddr, 0, sizeof(client->packet.yiaddr)); memset(&client->packet.siaddr, 0, sizeof(client->packet.siaddr)); memset(&client->packet.giaddr, 0, sizeof(client->packet.giaddr)); memcpy(client->packet.chaddr, ifi->hw_address.haddr, ifi->hw_address.hlen); } void free_client_lease(struct client_lease *lease) { int i; if (lease->server_name) free(lease->server_name); if (lease->filename) free(lease->filename); for (i = 0; i < 256; i++) { if (lease->options[i].len) free(lease->options[i].data); } free(lease); } void rewrite_client_leases(void) { struct client_lease *lp; if (!leaseFile) /* XXX */ error("lease file not open"); fflush(leaseFile); rewind(leaseFile); for (lp = client->leases; lp; lp = lp->next) write_client_lease(lp, 1); if (client->active) write_client_lease(client->active, 1); fflush(leaseFile); ftruncate(fileno(leaseFile), ftello(leaseFile)); fsync(fileno(leaseFile)); } void write_client_lease(struct client_lease *lease, int rewrite) { static int leases_written; struct tm *t; int i; if (!rewrite) { if (leases_written++ > 20) { rewrite_client_leases(); leases_written = 0; } } /* If the lease came from the config file, we don't need to stash a copy in the lease database. */ if (lease->is_static) return; if (!leaseFile) /* XXX */ error("lease file not open"); fprintf(leaseFile, "lease {\n"); if (lease->is_bootp) fprintf(leaseFile, " bootp;\n"); fprintf(leaseFile, " interface \"%s\";\n", ifi->name); fprintf(leaseFile, " fixed-address %s;\n", piaddr(lease->address)); if (lease->filename) fprintf(leaseFile, " filename \"%s\";\n", lease->filename); if (lease->server_name) fprintf(leaseFile, " server-name \"%s\";\n", lease->server_name); for (i = 0; i < 256; i++) if (lease->options[i].len) fprintf(leaseFile, " option %s %s;\n", dhcp_options[i].name, pretty_print_option(i, lease->options[i].data, lease->options[i].len, 1, 1)); t = gmtime(&lease->renewal); fprintf(leaseFile, " renew %d %d/%d/%d %02d:%02d:%02d;\n", t->tm_wday, t->tm_year + 1900, t->tm_mon + 1, t->tm_mday, t->tm_hour, t->tm_min, t->tm_sec); t = gmtime(&lease->rebind); fprintf(leaseFile, " rebind %d %d/%d/%d %02d:%02d:%02d;\n", t->tm_wday, t->tm_year + 1900, t->tm_mon + 1, t->tm_mday, t->tm_hour, t->tm_min, t->tm_sec); t = gmtime(&lease->expiry); fprintf(leaseFile, " expire %d %d/%d/%d %02d:%02d:%02d;\n", t->tm_wday, t->tm_year + 1900, t->tm_mon + 1, t->tm_mday, t->tm_hour, t->tm_min, t->tm_sec); fprintf(leaseFile, "}\n"); fflush(leaseFile); } void script_init(char *reason) { size_t len; struct imsg_hdr hdr; struct buf *buf; hdr.code = IMSG_SCRIPT_INIT; hdr.len = sizeof(struct imsg_hdr) + sizeof(size_t) + strlen(reason); buf = buf_open(hdr.len); buf_add(buf, &hdr, sizeof(hdr)); len = strlen(reason); buf_add(buf, &len, sizeof(len)); buf_add(buf, reason, len); buf_close(privfd, buf); } void priv_script_init(char *reason) { char *rdomain; client->scriptEnvsize = 100; if (client->scriptEnv == NULL) client->scriptEnv = calloc(client->scriptEnvsize, sizeof(char *)); if (client->scriptEnv == NULL) error("script_init: no memory for environment"); client->scriptEnv[0] = strdup(CLIENT_PATH); if (client->scriptEnv[0] == NULL) error("script_init: no memory for environment"); client->scriptEnv[1] = NULL; script_set_env("", "interface", ifi->name); if (asprintf(&rdomain, "-T %d", ifi->rdomain) == -1) error("script_init: no memory for environment"); script_set_env("", "rdomain", rdomain); free(rdomain); script_set_env("", "reason", reason); } void priv_script_write_params(char *prefix, struct client_lease *lease) { u_int8_t dbuf[1500]; int i, len = 0; char tbuf[128]; script_set_env(prefix, "ip_address", piaddr(lease->address)); if (lease->options[DHO_SUBNET_MASK].len && (lease->options[DHO_SUBNET_MASK].len < sizeof(lease->address.iabuf))) { struct iaddr netmask, subnet, broadcast; memcpy(netmask.iabuf, lease->options[DHO_SUBNET_MASK].data, lease->options[DHO_SUBNET_MASK].len); netmask.len = lease->options[DHO_SUBNET_MASK].len; subnet = subnet_number(lease->address, netmask); if (subnet.len) { script_set_env(prefix, "network_number", piaddr(subnet)); if (!lease->options[DHO_BROADCAST_ADDRESS].len) { broadcast = broadcast_addr(subnet, netmask); if (broadcast.len) script_set_env(prefix, "broadcast_address", piaddr(broadcast)); } } } if (lease->filename) script_set_env(prefix, "filename", lease->filename); if (lease->server_name) script_set_env(prefix, "server_name", lease->server_name); for (i = 0; i < 256; i++) { u_int8_t *dp = NULL; if (config->defaults[i].len) { if (lease->options[i].len) { switch (config->default_actions[i]) { case ACTION_DEFAULT: dp = lease->options[i].data; len = lease->options[i].len; break; case ACTION_SUPERSEDE: supersede: dp = config->defaults[i].data; len = config->defaults[i].len; break; case ACTION_PREPEND: len = config->defaults[i].len + lease->options[i].len; if (len >= sizeof(dbuf)) { warning("no space to %s %s", "prepend option", dhcp_options[i].name); goto supersede; } dp = dbuf; memcpy(dp, config->defaults[i].data, config->defaults[i].len); memcpy(dp + config->defaults[i].len, lease->options[i].data, lease->options[i].len); dp[len] = '\0'; break; case ACTION_APPEND: len = config->defaults[i].len + lease->options[i].len; if (len >= sizeof(dbuf)) { warning("no space to %s %s", "append option", dhcp_options[i].name); goto supersede; } dp = dbuf; memcpy(dp, lease->options[i].data, lease->options[i].len); memcpy(dp + lease->options[i].len, config->defaults[i].data, config->defaults[i].len); dp[len] = '\0'; } } else { dp = config->defaults[i].data; len = config->defaults[i].len; } } else if (lease->options[i].len) { len = lease->options[i].len; dp = lease->options[i].data; } else { len = 0; } if (len) { char name[256]; if (dhcp_option_ev_name(name, sizeof(name), &dhcp_options[i])) script_set_env(prefix, name, pretty_print_option(i, dp, len, 0, 0)); } } snprintf(tbuf, sizeof(tbuf), "%d", (int)lease->expiry); script_set_env(prefix, "expiry", tbuf); } void script_write_params(char *prefix, struct client_lease *lease) { size_t fn_len = 0, sn_len = 0, pr_len = 0; struct imsg_hdr hdr; struct buf *buf; int i; if (lease->filename != NULL) fn_len = strlen(lease->filename); if (lease->server_name != NULL) sn_len = strlen(lease->server_name); if (prefix != NULL) pr_len = strlen(prefix); hdr.code = IMSG_SCRIPT_WRITE_PARAMS; hdr.len = sizeof(hdr) + sizeof(struct client_lease) + sizeof(size_t) + fn_len + sizeof(size_t) + sn_len + sizeof(size_t) + pr_len; for (i = 0; i < 256; i++) hdr.len += sizeof(int) + lease->options[i].len; scripttime = time(NULL); buf = buf_open(hdr.len); buf_add(buf, &hdr, sizeof(hdr)); buf_add(buf, lease, sizeof(struct client_lease)); buf_add(buf, &fn_len, sizeof(fn_len)); buf_add(buf, lease->filename, fn_len); buf_add(buf, &sn_len, sizeof(sn_len)); buf_add(buf, lease->server_name, sn_len); buf_add(buf, &pr_len, sizeof(pr_len)); buf_add(buf, prefix, pr_len); for (i = 0; i < 256; i++) { buf_add(buf, &lease->options[i].len, sizeof(lease->options[i].len)); buf_add(buf, lease->options[i].data, lease->options[i].len); } buf_close(privfd, buf); } int script_go(void) { struct imsg_hdr hdr; struct buf *buf; int ret; scripttime = time(NULL); hdr.code = IMSG_SCRIPT_GO; hdr.len = sizeof(struct imsg_hdr); buf = buf_open(hdr.len); buf_add(buf, &hdr, sizeof(hdr)); buf_close(privfd, buf); bzero(&hdr, sizeof(hdr)); buf_read(privfd, &hdr, sizeof(hdr)); if (hdr.code != IMSG_SCRIPT_GO_RET) error("unexpected msg type %u", hdr.code); if (hdr.len != sizeof(hdr) + sizeof(int)) error("received corrupted message"); buf_read(privfd, &ret, sizeof(ret)); return (ret); } int priv_script_go(void) { char *scriptName, *argv[2], **envp; int pid, wpid, wstatus; scripttime = time(NULL); scriptName = config->script_name; envp = client->scriptEnv; argv[0] = scriptName; argv[1] = NULL; pid = fork(); if (pid < 0) { error("fork: %m"); wstatus = 0; } else if (pid) { do { wpid = wait(&wstatus); } while (wpid != pid && wpid > 0); if (wpid < 0) { error("wait: %m"); wstatus = 0; } } else { execve(scriptName, argv, envp); error("execve (%s, ...): %m", scriptName); } script_flush_env(); return (WEXITSTATUS(wstatus)); } void script_set_env(const char *prefix, const char *name, const char *value) { int i, j, namelen; namelen = strlen(name); for (i = 0; client->scriptEnv[i]; i++) if (strncmp(client->scriptEnv[i], name, namelen) == 0 && client->scriptEnv[i][namelen] == '=') break; if (client->scriptEnv[i]) /* Reuse the slot. */ free(client->scriptEnv[i]); else { /* New variable. Expand if necessary. */ if (i >= client->scriptEnvsize - 1) { char **newscriptEnv; int newscriptEnvsize = client->scriptEnvsize + 50; newscriptEnv = realloc(client->scriptEnv, newscriptEnvsize); if (newscriptEnv == NULL) { free(client->scriptEnv); client->scriptEnv = NULL; client->scriptEnvsize = 0; error("script_set_env: no memory for variable"); } client->scriptEnv = newscriptEnv; client->scriptEnvsize = newscriptEnvsize; } /* need to set the NULL pointer at end of array beyond the new slot. */ client->scriptEnv[i + 1] = NULL; } /* Allocate space and format the variable in the appropriate slot. */ client->scriptEnv[i] = malloc(strlen(prefix) + strlen(name) + 1 + strlen(value) + 1); if (client->scriptEnv[i] == NULL) error("script_set_env: no memory for variable assignment"); /* No `` or $() command substitution allowed in environment values! */ for (j = 0; j < strlen(value); j++) switch (value[j]) { case '`': case '$': error("illegal character (%c) in value '%s'", value[j], value); /* not reached */ } snprintf(client->scriptEnv[i], strlen(prefix) + strlen(name) + 1 + strlen(value) + 1, "%s%s=%s", prefix, name, value); } void script_flush_env(void) { int i; for (i = 0; client->scriptEnv[i]; i++) { free(client->scriptEnv[i]); client->scriptEnv[i] = NULL; } client->scriptEnvsize = 0; } int dhcp_option_ev_name(char *buf, size_t buflen, const struct option *option) { int i; for (i = 0; option->name[i]; i++) { if (i + 1 == buflen) return 0; if (option->name[i] == '-') buf[i] = '_'; else buf[i] = option->name[i]; } buf[i] = 0; return 1; } void go_daemon(void) { static int state = 0; if (no_daemon || state) return; state = 1; /* Stop logging to stderr... */ log_perror = 0; if (daemon(1, 0) == -1) error("daemon"); /* we are chrooted, daemon(3) fails to open /dev/null */ if (nullfd != -1) { dup2(nullfd, STDIN_FILENO); dup2(nullfd, STDOUT_FILENO); dup2(nullfd, STDERR_FILENO); close(nullfd); nullfd = -1; } } int check_option(struct client_lease *l, int option) { char *opbuf; char *sbuf; /* we use this, since this is what gets passed to dhclient-script */ opbuf = pretty_print_option(option, l->options[option].data, l->options[option].len, 0, 0); sbuf = option_as_string(option, l->options[option].data, l->options[option].len); switch (option) { case DHO_SUBNET_MASK: case DHO_SWAP_SERVER: case DHO_BROADCAST_ADDRESS: case DHO_DHCP_SERVER_IDENTIFIER: case DHO_ROUTER_SOLICITATION_ADDRESS: case DHO_DHCP_REQUESTED_ADDRESS: if (ipv4addrs(opbuf) == 0) { warning("Invalid IP address in option %s: %s", dhcp_options[option].name, opbuf); return (0); } if (l->options[option].len != 4) { /* RFC 2132 */ warning("warning: Only 1 IP address allowed in " "%s option; length %d, must be 4", dhcp_options[option].name, l->options[option].len); l->options[option].len = 4; } return (1); case DHO_TIME_SERVERS: case DHO_NAME_SERVERS: case DHO_ROUTERS: case DHO_DOMAIN_NAME_SERVERS: case DHO_LOG_SERVERS: case DHO_COOKIE_SERVERS: case DHO_LPR_SERVERS: case DHO_IMPRESS_SERVERS: case DHO_RESOURCE_LOCATION_SERVERS: case DHO_NIS_SERVERS: case DHO_NTP_SERVERS: case DHO_NETBIOS_NAME_SERVERS: case DHO_NETBIOS_DD_SERVER: case DHO_FONT_SERVERS: if (ipv4addrs(opbuf) == 0) { warning("Invalid IP address in option %s: %s", dhcp_options[option].name, opbuf); return (0); } return (1); case DHO_HOST_NAME: case DHO_DOMAIN_NAME: case DHO_NIS_DOMAIN: if (!res_hnok(sbuf)) { warning("Bogus Host Name option %d: %s (%s)", option, sbuf, opbuf); l->options[option].len = 0; free(l->options[option].data); } return (1); case DHO_PAD: case DHO_TIME_OFFSET: case DHO_BOOT_SIZE: case DHO_MERIT_DUMP: case DHO_ROOT_PATH: case DHO_EXTENSIONS_PATH: case DHO_IP_FORWARDING: case DHO_NON_LOCAL_SOURCE_ROUTING: case DHO_POLICY_FILTER: case DHO_MAX_DGRAM_REASSEMBLY: case DHO_DEFAULT_IP_TTL: case DHO_PATH_MTU_AGING_TIMEOUT: case DHO_PATH_MTU_PLATEAU_TABLE: case DHO_INTERFACE_MTU: case DHO_ALL_SUBNETS_LOCAL: case DHO_PERFORM_MASK_DISCOVERY: case DHO_MASK_SUPPLIER: case DHO_ROUTER_DISCOVERY: case DHO_STATIC_ROUTES: case DHO_TRAILER_ENCAPSULATION: case DHO_ARP_CACHE_TIMEOUT: case DHO_IEEE802_3_ENCAPSULATION: case DHO_DEFAULT_TCP_TTL: case DHO_TCP_KEEPALIVE_INTERVAL: case DHO_TCP_KEEPALIVE_GARBAGE: case DHO_VENDOR_ENCAPSULATED_OPTIONS: case DHO_NETBIOS_NODE_TYPE: case DHO_NETBIOS_SCOPE: case DHO_X_DISPLAY_MANAGER: case DHO_DHCP_LEASE_TIME: case DHO_DHCP_OPTION_OVERLOAD: case DHO_DHCP_MESSAGE_TYPE: case DHO_DHCP_PARAMETER_REQUEST_LIST: case DHO_DHCP_MESSAGE: case DHO_DHCP_MAX_MESSAGE_SIZE: case DHO_DHCP_RENEWAL_TIME: case DHO_DHCP_REBINDING_TIME: case DHO_DHCP_CLASS_IDENTIFIER: case DHO_DHCP_CLIENT_IDENTIFIER: case DHO_DHCP_USER_CLASS_ID: case DHO_TFTP_SERVER: case DHO_END: return (1); default: if (!unknown_ok) warning("unknown dhcp option value 0x%x", option); return (unknown_ok); } } int res_hnok(const char *name) { const char *dn = name; int pch = '.', ch = *dn++; int warn = 0; while (ch != '\0') { int nch = *dn++; if (ch == '.') { ; } else if (pch == '.' || nch == '.' || nch == '\0') { if (!isalnum(ch)) return (0); } else if (!isalnum(ch) && ch != '-' && ch != '_') return (0); else if (ch == '_' && warn == 0) { warning("warning: hostname %s contains an " "underscore which violates RFC 952", name); warn++; } pch = ch, ch = nch; } return (1); } /* Does buf consist only of dotted decimal ipv4 addrs? * return how many if so, * otherwise, return 0 */ int ipv4addrs(char * buf) { struct in_addr jnk; int count = 0; while (inet_aton(buf, &jnk) == 1){ count++; while (*buf == '.' || isdigit(*buf)) buf++; if (*buf == '\0') return (count); while (*buf == ' ') buf++; } return (0); } char * option_as_string(unsigned int code, unsigned char *data, int len) { static char optbuf[32768]; /* XXX */ char *op = optbuf; int opleft = sizeof(optbuf); unsigned char *dp = data; if (code > 255) error("option_as_string: bad code %d", code); for (; dp < data + len; dp++) { if (!isascii(*dp) || !isprint(*dp)) { if (dp + 1 != data + len || *dp != 0) { size_t oplen; snprintf(op, opleft, "\\%03o", *dp); oplen = strlen(op); op += oplen; opleft -= oplen; } } else if (*dp == '"' || *dp == '\'' || *dp == '$' || *dp == '`' || *dp == '\\') { *op++ = '\\'; *op++ = *dp; opleft -= 2; } else { *op++ = *dp; opleft--; } } if (opleft < 1) goto toobig; *op = 0; return optbuf; toobig: warning("dhcp option too large"); return ""; } int fork_privchld(int fd, int fd2) { struct pollfd pfd[1]; int nfds; switch (fork()) { case -1: error("cannot fork"); break; case 0: break; default: return (0); } if (chdir("/") == -1) error("chdir(\"/\")"); setproctitle("%s [priv]", ifi->name); dup2(nullfd, STDIN_FILENO); dup2(nullfd, STDOUT_FILENO); dup2(nullfd, STDERR_FILENO); close(nullfd); close(fd2); for (;;) { pfd[0].fd = fd; pfd[0].events = POLLIN; if ((nfds = poll(pfd, 1, INFTIM)) == -1) if (errno != EINTR) error("poll error"); if (nfds == 0 || !(pfd[0].revents & POLLIN)) continue; dispatch_imsg(fd); } } void get_ifname(char *ifname, char *arg) { struct ifgroupreq ifgr; struct ifg_req *ifg; int s, len; if (!strcmp(arg, "egress")) { s = socket(AF_INET, SOCK_DGRAM, 0); if (s == -1) error("socket error"); bzero(&ifgr, sizeof(ifgr)); strlcpy(ifgr.ifgr_name, "egress", sizeof(ifgr.ifgr_name)); if (ioctl(s, SIOCGIFGMEMB, (caddr_t)&ifgr) == -1) { if (errno == ENOENT) error("no interface in group egress found"); error("ioctl SIOCGIFGMEMB: %m"); } len = ifgr.ifgr_len; if ((ifgr.ifgr_groups = calloc(1, len)) == NULL) error("get_ifname"); if (ioctl(s, SIOCGIFGMEMB, (caddr_t)&ifgr) == -1) error("ioctl SIOCGIFGMEMB: %m"); arg = NULL; for (ifg = ifgr.ifgr_groups; ifg && len >= sizeof(struct ifg_req); ifg++) { len -= sizeof(struct ifg_req); if (arg) error("too many interfaces in group egress"); arg = ifg->ifgrq_member; } if (strlcpy(ifi->name, arg, IFNAMSIZ) >= IFNAMSIZ) error("Interface name too long: %m"); free(ifgr.ifgr_groups); close(s); } else if (strlcpy(ifi->name, arg, IFNAMSIZ) >= IFNAMSIZ) error("Interface name too long"); }