/* $OpenBSD: dhclient.c,v 1.9 2004/02/10 13:12:48 henning Exp $ */ /* DHCP Client. */ /* * 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 "dhcpd.h" #define PERIOD 0x2e #define hyphenchar(c) ((c) == 0x2d) #define bslashchar(c) ((c) == 0x5c) #define periodchar(c) ((c) == PERIOD) #define asterchar(c) ((c) == 0x2a) #define alphachar(c) (((c) >= 0x41 && (c) <= 0x5a) || \ ((c) >= 0x61 && (c) <= 0x7a)) #define digitchar(c) ((c) >= 0x30 && (c) <= 0x39) #define borderchar(c) (alphachar(c) || digitchar(c)) #define middlechar(c) (borderchar(c) || hyphenchar(c)) #define domainchar(c) ((c) > 0x20 && (c) < 0x7f) #define CLIENT_PATH "PATH=/usr/bin:/usr/sbin:/bin:/sbin" TIME cur_time; TIME default_lease_time = 43200; /* 12 hours... */ TIME max_lease_time = 86400; /* 24 hours... */ struct tree_cache *global_options[256]; char *path_dhclient_conf = _PATH_DHCLIENT_CONF; char *path_dhclient_db = _PATH_DHCLIENT_DB; char *path_dhclient_pid = _PATH_DHCLIENT_PID; int interfaces_requested = 0; int log_perror = 1; struct iaddr iaddr_broadcast = { 4, { 255, 255, 255, 255 } }; struct iaddr iaddr_any = { 4, { 0, 0, 0, 0 } }; struct in_addr inaddr_any; struct sockaddr_in sockaddr_broadcast; /* * ASSERT_STATE() does nothing now; it used to be * assert (state_is == state_shouldbe). */ #define ASSERT_STATE(state_is, state_shouldbe) {} u_int16_t local_port; u_int16_t remote_port; int log_priority; int no_daemon; int save_scripts; int onetry = 0; int unknown_ok = 1; static void usage(char *); static int check_option(struct client_lease *l, int option); static int ipv4addrs(char * buf); static int res_hnok(const char *dn); char *option_as_string(unsigned int code, unsigned char *data, int len); int routefd; struct interface_info * isours(u_int16_t index) { struct interface_info *ip; for (ip = interfaces; ip; ip = ip->next) if (index == ip->index) return (ip); return (NULL); } #define ROUNDUP(a) \ ((a) > 0 ? (1 + (((a) - 1) | (sizeof(long) - 1))) : sizeof(long)) #define ADVANCE(x, n) (x += ROUNDUP((n)->sa_len)) 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); } void routehandler(struct protocol *p) { char msg[2048]; struct rt_msghdr *rtm; struct if_msghdr *ifm; struct ifa_msghdr *ifam; struct interface_info *ip; ssize_t n; n = read(routefd, &msg, sizeof(msg)); 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 ((ip = isours(ifam->ifam_index)) == NULL) break; if (findproto((char *)(ifam + 1), ifam->ifam_addrs) != AF_INET) break; /* goto die; */ break; case RTM_DELADDR: ifam = (struct ifa_msghdr *)rtm; if ((ip = isours(ifam->ifam_index)) == NULL) break; if (findproto((char *)(ifam + 1), ifam->ifam_addrs) != AF_INET) break; goto die; break; case RTM_IFINFO: ifm = (struct if_msghdr *)rtm; if ((ip = isours(ifm->ifm_index)) == NULL) break; if ((rtm->rtm_flags & RTF_UP) == 0) goto die; break; default: break; } return; die: script_init(ip, "FAIL", NULL); if (ip->client->alias) script_write_params(ip, "alias_", ip->client->alias); script_go(ip); exit(1); } int main(int argc, char *argv[]) { int i, fd; struct servent *ent; struct interface_info *ip; int seed; int quiet = 0; char *s; int ifs = 0; s = strrchr(argv[0], '/'); if (!s) s = argv[0]; else s++; /* Initially, log errors to stderr as well as to syslogd. */ openlog(s, LOG_NDELAY, DHCPD_LOG_FACILITY); setlogmask(LOG_UPTO(LOG_INFO)); for (i = 1; i < argc; i++) { if (!strcmp(argv[i], "-p")) { if (++i == argc) usage(s); local_port = htons(atoi(argv[i])); debug("binding to user-specified port %d", ntohs(local_port)); } else if (!strcmp(argv[i], "-d")) { no_daemon = 1; } else if (!strcmp(argv[i], "-D")) { save_scripts = 1; } else if (!strcmp(argv[i], "-cf")) { if (++i == argc) usage(s); path_dhclient_conf = argv[i]; } else if (!strcmp(argv[i], "-pf")) { if (++i == argc) usage(s); path_dhclient_pid = argv[i]; } else if (!strcmp(argv[i], "-lf")) { if (++i == argc) usage(s); path_dhclient_db = argv[i]; } else if (!strcmp(argv[i], "-q")) { quiet = 1; quiet_interface_discovery = 1; } else if (!strcmp(argv[i], "-u")) { unknown_ok = 0; } else if (!strcmp(argv[i], "-1")) { onetry = 1; } else if (argv[i][0] == '-') { usage(s); } else { struct interface_info *tmp = dmalloc(sizeof(*tmp), "specified_interface"); if (!tmp) error("Insufficient memory to %s %s", "record interface", argv[i]); memset(tmp, 0, sizeof(*tmp)); strlcpy(tmp->name, argv[i], IFNAMSIZ); tmp->next = interfaces; tmp->flags = INTERFACE_REQUESTED; interfaces_requested = 1; interfaces = tmp; } } if (quiet) log_perror = 0; /* Default to the DHCP/BOOTP port. */ if (!local_port) { ent = getservbyname("dhcpc", "udp"); if (!ent) local_port = htons(68); else local_port = ent->s_port; } remote_port = htons(ntohs(local_port) - 1); /* XXX */ /* Get the current time... */ GET_TIME(&cur_time); memset(&sockaddr_broadcast, 0, sizeof(sockaddr_broadcast)); sockaddr_broadcast.sin_family = AF_INET; sockaddr_broadcast.sin_port = remote_port; sockaddr_broadcast.sin_addr.s_addr = INADDR_BROADCAST; sockaddr_broadcast.sin_len = sizeof(sockaddr_broadcast); inaddr_any.s_addr = INADDR_ANY; /* Discover all the network interfaces. */ discover_interfaces(DISCOVER_UNCONFIGURED); /* Parse the dhclient.conf file. */ read_client_conf(); /* Lock the leases file */ fd = open(path_dhclient_db, O_RDONLY | O_EXLOCK | O_CREAT, 0); if (fd < 0) error("can't open and lock %s: %m", path_dhclient_db); /* Parse the lease database. */ read_client_leases(); /* Rewrite the lease database... */ rewrite_client_leases(); /* Close and unlock */ close(fd); /* If no broadcast interfaces were discovered, call the script and tell it so. */ if (!interfaces) { script_init(NULL, "NBI", NULL); script_go(NULL); note("No broadcast interfaces found - exiting."); /* Nothing more to do. */ exit(0); } else { /* Call the script with the list of interfaces. */ for (ip = interfaces; ip; ip = ip->next) { /* If interfaces were specified, don't configure interfaces that weren't specified! */ if (interfaces_requested && ((ip->flags & (INTERFACE_REQUESTED | INTERFACE_AUTOMATIC)) != INTERFACE_REQUESTED)) continue; if (!interface_link_status(ip->name)) continue; ifs++; script_init(ip, "PREINIT", NULL); if (ip->client->alias) script_write_params(ip, "alias_", ip->client->alias); script_go(ip); } } if (ifs == 0) { note("No active interfaces found - exiting."); exit(0); } routefd = socket(PF_ROUTE, SOCK_RAW, 0); if (routefd != -1) add_protocol("AF_ROUTE", routefd, routehandler, interfaces); /* At this point, all the interfaces that the script thinks are relevant should be running, so now we once again call discover_interfaces(), and this time ask it to actually set up the interfaces. */ discover_interfaces(interfaces_requested ? DISCOVER_REQUESTED : DISCOVER_RUNNING); /* Make up a seed for the random number generator from current time plus the sum of the last four bytes of each interface's hardware address interpreted as an integer. Not much entropy, but we're booting, so we're not likely to find anything better. */ seed = 0; /* Unfortunately, what's on the stack isn't random. :') */ for (ip = interfaces; ip; ip = ip->next) { int junk; memcpy(&junk, &ip->hw_address.haddr[ip->hw_address.hlen - sizeof(seed)], sizeof(seed)); seed += junk; } srandom(seed + cur_time); /* Start a configuration state machine for each interface. */ for (ip = interfaces; ip; ip = ip->next) { ip->client->state = S_INIT; state_reboot(ip); } /* Set up the bootp packet handler... */ bootp_packet_handler = do_packet; /* Start dispatching packets and timeouts... */ dispatch(); /*NOTREACHED*/ return (0); } static void usage(char *appname) { warn("Usage: %s [-c1u] [-p ] [-lf lease-file]", appname); error(" [-pf pidfile] [interface]"); } void cleanup(void) { } /* * 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 *ipp) { struct interface_info *ip = ipp; /* If we don't remember an active lease, go straight to INIT. */ if (!ip->client->active || ip->client->active->is_bootp) { state_init(ip); return; } /* We are in the rebooting state. */ ip->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. */ ip->client->xid = random(); /* Make a DHCPREQUEST packet, and set appropriate per-interface flags. */ make_request(ip, ip->client->active); ip->client->destination = iaddr_broadcast; ip->client->first_sending = cur_time; ip->client->interval = ip->client->config->initial_interval; /* Zap the medium list... */ ip->client->medium = NULL; /* Send out the first DHCPREQUEST packet. */ send_request(ip); } /* Called when a lease has completely expired and we've been unable to renew it. */ void state_init(void *ipp) { struct interface_info *ip = ipp; ASSERT_STATE(state, S_INIT); /* Make a DHCPDISCOVER packet, and set appropriate per-interface flags. */ make_discover(ip, ip->client->active); ip->client->xid = ip->client->packet.xid; ip->client->destination = iaddr_broadcast; ip->client->state = S_SELECTING; ip->client->first_sending = cur_time; ip->client->interval = ip->client->config->initial_interval; /* Add an immediate timeout to cause the first DHCPDISCOVER packet to go out. */ send_discover(ip); } /* 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 *ipp) { struct interface_info *ip = ipp; struct client_lease *lp, *next, *picked; ASSERT_STATE(state, S_SELECTING); /* Cancel state_selecting and send_discover timeouts, since either one could have got us here. */ cancel_timeout(state_selecting, ip); cancel_timeout(send_discover, ip); /* 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 = ip->client->offered_leases; lp; lp = next) { next = lp->next; /* Check to see if we got an ARPREPLY for the address in this particular lease. */ if (!picked) { script_init(ip, "ARPCHECK", lp->medium); script_write_params(ip, "check_", lp); /* If the ARPCHECK code detects another machine using the offered address, it exits nonzero. We need to send a DHCPDECLINE and toss the lease. */ if (script_go(ip)) { make_decline(ip, lp); send_decline(ip); goto freeit; } picked = lp; picked->next = NULL; } else { freeit: free_client_lease(lp); } } ip->client->offered_leases = NULL; /* If we just tossed all the leases we were offered, go back to square one. */ if (!picked) { ip->client->state = S_INIT; state_init(ip); return; } /* If it was a BOOTREPLY, we can just take the address right now. */ if (!picked->options[DHO_DHCP_MESSAGE_TYPE].len) { ip->client->new = picked; /* Make up some lease expiry times XXX these should be configurable. */ ip->client->new->expiry = cur_time + 12000; ip->client->new->renewal += cur_time + 8000; ip->client->new->rebind += cur_time + 10000; ip->client->state = S_REQUESTING; /* Bind to the address we received. */ bind_lease(ip); return; } /* Go to the REQUESTING state. */ ip->client->destination = iaddr_broadcast; ip->client->state = S_REQUESTING; ip->client->first_sending = cur_time; ip->client->interval = ip->client->config->initial_interval; /* Make a DHCPREQUEST packet from the lease we picked. */ make_request(ip, picked); ip->client->xid = ip->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(ip); } /* state_requesting is called when we receive a DHCPACK message after having sent out one or more DHCPREQUEST packets. */ void dhcpack(struct packet *packet) { struct interface_info *ip = packet->interface; struct client_lease *lease; /* If we're not receptive to an offer right now, or if the offer has an unrecognizable transaction id, then just drop it. */ if (packet->interface->client->xid != packet->raw->xid || (packet->interface->hw_address.hlen != packet->raw->hlen) || (memcmp(packet->interface->hw_address.haddr, packet->raw->chaddr, packet->raw->hlen))) { #ifdef DEBUG debug("DHCPACK in wrong transaction."); #endif return; } if (ip->client->state != S_REBOOTING && ip->client->state != S_REQUESTING && ip->client->state != S_RENEWING && ip->client->state != S_REBINDING) { #ifdef DEBUG debug("DHCPACK in wrong state."); #endif return; } note("DHCPACK from %s", piaddr(packet->client_addr)); lease = packet_to_lease(packet); if (!lease) { note("packet_to_lease failed."); return; } ip->client->new = lease; /* Stop resending DHCPREQUEST. */ cancel_timeout(send_request, ip); /* Figure out the lease time. */ if (ip->client->new->options[DHO_DHCP_LEASE_TIME].data) ip->client->new->expiry = getULong( ip->client->new->options[DHO_DHCP_LEASE_TIME].data); else ip->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 (ip->client->new->expiry < 0) ip->client->new->expiry = TIME_MAX; /* Take the server-provided renewal time if there is one; otherwise figure it out according to the spec. */ if (ip->client->new->options[DHO_DHCP_RENEWAL_TIME].len) ip->client->new->renewal = getULong( ip->client->new->options[DHO_DHCP_RENEWAL_TIME].data); else ip->client->new->renewal = ip->client->new->expiry / 2; /* Same deal with the rebind time. */ if (ip->client->new->options[DHO_DHCP_REBINDING_TIME].len) ip->client->new->rebind = getULong( ip->client->new->options[DHO_DHCP_REBINDING_TIME].data); else ip->client->new->rebind = ip->client->new->renewal + ip->client->new->renewal / 2 + ip->client->new->renewal / 4; ip->client->new->expiry += cur_time; /* Lease lengths can never be negative. */ if (ip->client->new->expiry < cur_time) ip->client->new->expiry = TIME_MAX; ip->client->new->renewal += cur_time; if (ip->client->new->renewal < cur_time) ip->client->new->renewal = TIME_MAX; ip->client->new->rebind += cur_time; if (ip->client->new->rebind < cur_time) ip->client->new->rebind = TIME_MAX; bind_lease(ip); } void bind_lease(struct interface_info *ip) { /* Remember the medium. */ ip->client->new->medium = ip->client->medium; /* Write out the new lease. */ write_client_lease(ip, ip->client->new, 0); /* Run the client script with the new parameters. */ script_init(ip, (ip->client->state == S_REQUESTING ? "BOUND" : (ip->client->state == S_RENEWING ? "RENEW" : (ip->client->state == S_REBOOTING ? "REBOOT" : "REBIND"))), ip->client->new->medium); if (ip->client->active && ip->client->state != S_REBOOTING) script_write_params(ip, "old_", ip->client->active); script_write_params(ip, "new_", ip->client->new); if (ip->client->alias) script_write_params(ip, "alias_", ip->client->alias); script_go(ip); /* Replace the old active lease with the new one. */ if (ip->client->active) free_client_lease(ip->client->active); ip->client->active = ip->client->new; ip->client->new = NULL; /* Set up a timeout to start the renewal process. */ add_timeout(ip->client->active->renewal, state_bound, ip); note("bound to %s -- renewal in %d seconds.", piaddr(ip->client->active->address), ip->client->active->renewal - cur_time); ip->client->state = S_BOUND; reinitialize_interfaces(); 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 *ipp) { struct interface_info *ip = ipp; ASSERT_STATE(state, S_BOUND); /* T1 has expired. */ make_request(ip, ip->client->active); ip->client->xid = ip->client->packet.xid; if (ip->client->active->options[DHO_DHCP_SERVER_IDENTIFIER].len == 4) { memcpy(ip->client->destination.iabuf, ip->client->active-> options[DHO_DHCP_SERVER_IDENTIFIER].data, 4); ip->client->destination.len = 4; } else ip->client->destination = iaddr_broadcast; ip->client->first_sending = cur_time; ip->client->interval = ip->client->config->initial_interval; ip->client->state = S_RENEWING; /* Send the first packet immediately. */ send_request(ip); } int commit_leases(void) { return (0); } int write_lease(struct lease *lease) { return (0); } void db_startup(void) { } void bootp(struct packet *packet) { struct iaddrlist *ap; if (packet->raw->op != BOOTREPLY) return; /* If there's a reject list, make sure this packet's sender isn't on it. */ for (ap = packet->interface->client->config->reject_list; ap; ap = ap->next) { if (addr_eq(packet->client_addr, ap->addr)) { note("BOOTREPLY from %s rejected.", piaddr(ap->addr)); return; } } dhcpoffer(packet); } void dhcp(struct packet *packet) { struct iaddrlist *ap; void (*handler)(struct packet *); char *type; switch (packet->packet_type) { case DHCPOFFER: handler = dhcpoffer; type = "DHCPOFFER"; break; case DHCPNAK: handler = dhcpnak; type = "DHCPNACK"; break; case DHCPACK: handler = dhcpack; type = "DHCPACK"; break; default: return; } /* If there's a reject list, make sure this packet's sender isn't on it. */ for (ap = packet->interface->client->config->reject_list; ap; ap = ap->next) { if (addr_eq(packet->client_addr, ap->addr)) { note("%s from %s rejected.", type, piaddr(ap->addr)); return; } } (*handler)(packet); } void dhcpoffer(struct packet *packet) { struct interface_info *ip = packet->interface; struct client_lease *lease, *lp; int i; int arp_timeout_needed, stop_selecting; char *name = packet->options[DHO_DHCP_MESSAGE_TYPE].len ? "DHCPOFFER" : "BOOTREPLY"; #ifdef DEBUG_PACKET dump_packet(packet); #endif /* If we're not receptive to an offer right now, or if the offer has an unrecognizable transaction id, then just drop it. */ if (ip->client->state != S_SELECTING || packet->interface->client->xid != packet->raw->xid || (packet->interface->hw_address.hlen != packet->raw->hlen) || (memcmp(packet->interface->hw_address.haddr, packet->raw->chaddr, packet->raw->hlen))) { #ifdef DEBUG debug("%s in wrong transaction.", name); #endif return; } note("%s from %s", name, piaddr(packet->client_addr)); /* If this lease doesn't supply the minimum required parameters, blow it off. */ for (i = 0; ip->client->config->required_options[i]; i++) { if (!packet->options[ip->client->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 = ip->client->offered_leases; lease; lease = lease->next) { if (lease->address.len == sizeof(packet->raw->yiaddr) && !memcmp(lease->address.iabuf, &packet->raw->yiaddr, lease->address.len)) { debug("%s already seen.", name); return; } } lease = packet_to_lease(packet); if (!lease) { note("packet_to_lease failed."); return; } /* If this lease was acquired through a BOOTREPLY, record that fact. */ if (!packet->options[DHO_DHCP_MESSAGE_TYPE].len) lease->is_bootp = 1; /* Record the medium under which this lease was offered. */ lease->medium = ip->client->medium; /* Send out an ARP Request for the offered IP address. */ script_init(ip, "ARPSEND", lease->medium); script_write_params(ip, "check_", lease); /* If the script can't send an ARP request without waiting, we'll be waiting when we do the ARPCHECK, so don't wait now. */ if (script_go(ip)) arp_timeout_needed = 0; else arp_timeout_needed = 2; /* Figure out when we're supposed to stop selecting. */ stop_selecting = ip->client->first_sending + ip->client->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 (lease->address.len == ip->client->requested_address.len && !memcmp(lease->address.iabuf, ip->client->requested_address.iabuf, ip->client->requested_address.len)) { lease->next = ip->client->offered_leases; ip->client->offered_leases = lease; } else { /* If we already have an offer, and arping for this offer would take us past the selection timeout, then don't extend the timeout - just hope for the best. */ if (ip->client->offered_leases && (cur_time + arp_timeout_needed) > stop_selecting) arp_timeout_needed = 0; /* Put the lease at the end of the list. */ lease->next = NULL; if (!ip->client->offered_leases) ip->client->offered_leases = lease; else { for (lp = ip->client->offered_leases; lp->next; lp = lp->next) ; /* nothing */ lp->next = lease; } } /* If we're supposed to stop selecting before we've had time to wait for the ARPREPLY, add some delay to wait for the ARPREPLY. */ if (stop_selecting - cur_time < arp_timeout_needed) stop_selecting = cur_time + arp_timeout_needed; /* If the selecting interval has expired, go immediately to state_selecting(). Otherwise, time out into state_selecting at the select interval. */ if (stop_selecting <= 0) state_selecting(ip); else { add_timeout(stop_selecting, state_selecting, ip); cancel_timeout(send_discover, ip); } } /* Allocate a client_lease structure and initialize it from the parameters in the specified packet. */ struct client_lease * packet_to_lease(struct packet *packet) { struct client_lease *lease; int i; lease = malloc(sizeof(struct client_lease)); if (!lease) { warn("dhcpoffer: no memory to record lease."); return (NULL); } memset(lease, 0, sizeof(*lease)); /* Copy the lease options. */ for (i = 0; i < 256; i++) { if (packet->options[i].len) { lease->options[i].data = malloc(packet->options[i].len + 1); if (!lease->options[i].data) { warn("dhcpoffer: no memory for option %d", i); free_client_lease(lease); return (NULL); } else { memcpy(lease->options[i].data, packet->options[i].data, packet->options[i].len); lease->options[i].len = packet->options[i].len; lease->options[i].data[lease->options[i].len] = 0; } if (!check_option(lease,i)) { /* ignore a bogus lease offer */ warn("Invalid lease option - ignoring offer"); free_client_lease(lease); return (NULL); } } } lease->address.len = sizeof(packet->raw->yiaddr); memcpy(lease->address.iabuf, &packet->raw->yiaddr, lease->address.len); /* If the server name was filled out, copy it. */ if ((!packet->options[DHO_DHCP_OPTION_OVERLOAD].len || !(packet->options[DHO_DHCP_OPTION_OVERLOAD].data[0] & 2)) && packet->raw->sname[0]) { lease->server_name = malloc(DHCP_SNAME_LEN + 1); if (!lease->server_name) { warn("dhcpoffer: no memory for server name."); free_client_lease(lease); return (NULL); } memcpy(lease->server_name, packet->raw->sname, DHCP_SNAME_LEN); lease->server_name[DHCP_SNAME_LEN]='\0'; if (!res_hnok(lease->server_name) ) { warn("Bogus server name %s", lease->server_name ); free_client_lease(lease); return (NULL); } } /* Ditto for the filename. */ if ((!packet->options[DHO_DHCP_OPTION_OVERLOAD].len || !(packet->options[DHO_DHCP_OPTION_OVERLOAD].data[0] & 1)) && packet->raw->file[0]) { /* Don't count on the NUL terminator. */ lease->filename = malloc(DHCP_FILE_LEN + 1); if (!lease->filename) { warn("dhcpoffer: no memory for filename."); free_client_lease(lease); return (NULL); } memcpy(lease->filename, packet->raw->file, DHCP_FILE_LEN); lease->filename[DHCP_FILE_LEN]='\0'; } return lease; } void dhcpnak(struct packet *packet) { struct interface_info *ip = packet->interface; /* If we're not receptive to an offer right now, or if the offer has an unrecognizable transaction id, then just drop it. */ if (packet->interface->client->xid != packet->raw->xid || (packet->interface->hw_address.hlen != packet->raw->hlen) || (memcmp(packet->interface->hw_address.haddr, packet->raw->chaddr, packet->raw->hlen))) { #ifdef DEBUG debug("DHCPNAK in wrong transaction."); #endif return; } if (ip->client->state != S_REBOOTING && ip->client->state != S_REQUESTING && ip->client->state != S_RENEWING && ip->client->state != S_REBINDING) { #ifdef DEBUG debug("DHCPNAK in wrong state."); #endif return; } note("DHCPNAK from %s", piaddr(packet->client_addr)); if (!ip->client->active) { note("DHCPNAK with no active lease.\n"); return; } free_client_lease(ip->client->active); ip->client->active = NULL; /* Stop sending DHCPREQUEST packets... */ cancel_timeout(send_request, ip); ip->client->state = S_INIT; state_init(ip); } /* 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 *ipp) { struct interface_info *ip = ipp; int result; int interval; int increase = 1; /* Figure out how long it's been since we started transmitting. */ interval = cur_time - ip->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 > ip->client->config->timeout) { state_panic(ip); return; } /* If we're selecting media, try the whole list before doing the exponential backoff, but if we've already received an offer, stop looping, because we obviously have it right. */ if (!ip->client->offered_leases && ip->client->config->media) { int fail = 0; again: if (ip->client->medium) { ip->client->medium = ip->client->medium->next; increase = 0; } if (!ip->client->medium) { if (fail) error("No valid media types for %s!", ip->name); ip->client->medium = ip->client->config->media; increase = 1; } note("Trying medium \"%s\" %d", ip->client->medium->string, increase); script_init(ip, "MEDIUM", ip->client->medium); if (script_go(ip)) goto again; } /* * 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 one; 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 (!ip->client->interval) ip->client->interval = ip->client->config->initial_interval; else { ip->client->interval += (random() >> 2) % (2 * ip->client->interval); } /* Don't backoff past cutoff. */ if (ip->client->interval > ip->client->config->backoff_cutoff) ip->client->interval = ((ip->client->config->backoff_cutoff / 2) + ((random () >> 2) % ip->client->config->backoff_cutoff)); } else if (!ip->client->interval) ip->client->interval = ip->client->config->initial_interval; /* If the backoff would take us to the panic timeout, just use that as the interval. */ if (cur_time + ip->client->interval > ip->client->first_sending + ip->client->config->timeout) ip->client->interval = (ip->client->first_sending + ip->client->config->timeout) - cur_time + 1; /* Record the number of seconds since we started sending. */ if (interval < 65536) ip->client->packet.secs = htons(interval); else ip->client->packet.secs = htons(65535); ip->client->secs = ip->client->packet.secs; note("DHCPDISCOVER on %s to %s port %d interval %d", ip->name, inet_ntoa(sockaddr_broadcast.sin_addr), ntohs(sockaddr_broadcast.sin_port), ip->client->interval); /* Send out a packet. */ result = send_packet(ip, NULL, &ip->client->packet, ip->client->packet_length, inaddr_any, &sockaddr_broadcast, NULL); add_timeout(cur_time + ip->client->interval, send_discover, ip); } /* * 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 *ipp) { struct interface_info *ip = ipp; struct client_lease *loop = ip->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 (!ip->client->active && ip->client->leases) goto activate_next; /* Run through the list of leases and see if one can be used. */ while (ip->client->active) { if (ip->client->active->expiry > cur_time) { note("Trying recorded lease %s", piaddr(ip->client->active->address)); /* Run the client script with the existing parameters. */ script_init(ip, "TIMEOUT", ip->client->active->medium); script_write_params(ip, "new_", ip->client->active); if (ip->client->alias) script_write_params(ip, "alias_", ip->client->alias); /* 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(ip)) { if (cur_time < ip->client->active->renewal) { ip->client->state = S_BOUND; note("bound: renewal in %d seconds.", ip->client->active->renewal - cur_time); add_timeout( ip->client->active->renewal, state_bound, ip); } else { ip->client->state = S_BOUND; note("bound: immediate renewal."); state_bound(ip); } reinitialize_interfaces(); go_daemon(); return; } } /* If there are no other leases, give up. */ if (!ip->client->leases) { ip->client->leases = ip->client->active; ip->client->active = NULL; break; } activate_next: /* Otherwise, put the active lease at the end of the lease list, and try another lease.. */ for (lp = ip->client->leases; lp->next; lp = lp->next) ; lp->next = ip->client->active; if (lp->next) lp->next->next = NULL; ip->client->active = ip->client->leases; ip->client->leases = ip->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 (ip->client->active == loop) break; else if (!loop) loop = ip->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. */ if (onetry) exit(1); note("No working leases in persistent database - sleeping.\n"); script_init(ip, "FAIL", NULL); if (ip->client->alias) script_write_params(ip, "alias_", ip->client->alias); script_go(ip); ip->client->state = S_INIT; add_timeout(cur_time + ip->client->config->retry_interval, state_init, ip); go_daemon(); } void send_request(void *ipp) { struct interface_info *ip = ipp; int result; int interval; struct sockaddr_in destination; struct in_addr from; /* Figure out how long it's been since we started transmitting. */ interval = cur_time - ip->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 ((ip->client->state == S_REBOOTING || ip->client->state == S_REQUESTING) && interval > ip->client->config->reboot_timeout) { cancel: ip->client->state = S_INIT; cancel_timeout(send_request, ip); state_init(ip); return; } /* If we're in the reboot state, make sure the media is set up correctly. */ if (ip->client->state == S_REBOOTING && !ip->client->medium && ip->client->active->medium ) { script_init(ip, "MEDIUM", ip->client->active->medium); /* If the medium we chose won't fly, go to INIT state. */ if (script_go(ip)) goto cancel; /* Record the medium. */ ip->client->medium = ip->client->active->medium; } /* If the lease has expired, relinquish the address and go back to the INIT state. */ if (ip->client->state != S_REQUESTING && cur_time > ip->client->active->expiry) { /* Run the client script with the new parameters. */ script_init(ip, "EXPIRE", NULL); script_write_params(ip, "old_", ip->client->active); if (ip->client->alias) script_write_params(ip, "alias_", ip->client->alias); script_go(ip); /* Now do a preinit on the interface so that we can discover a new address. */ script_init(ip, "PREINIT", NULL); if (ip->client->alias) script_write_params(ip, "alias_", ip->client->alias); script_go(ip); ip->client->state = S_INIT; state_init(ip); return; } /* Do the exponential backoff... */ if (!ip->client->interval) ip->client->interval = ip->client->config->initial_interval; else ip->client->interval += ((random () >> 2) % (2 * ip->client->interval)); /* Don't backoff past cutoff. */ if (ip->client->interval > ip->client->config->backoff_cutoff) ip->client->interval = ((ip->client->config->backoff_cutoff / 2) + ((random () >> 2) % ip->client->interval)); /* If the backoff would take us to the expiry time, just set the timeout to the expiry time. */ if (ip->client->state != S_REQUESTING && cur_time + ip->client->interval > ip->client->active->expiry) ip->client->interval = ip->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 (ip->client->state == S_REQUESTING || ip->client->state == S_REBOOTING || cur_time > ip->client->active->rebind) destination.sin_addr.s_addr = INADDR_BROADCAST; else memcpy(&destination.sin_addr.s_addr, ip->client->destination.iabuf, sizeof(destination.sin_addr.s_addr)); destination.sin_port = remote_port; destination.sin_family = AF_INET; destination.sin_len = sizeof(destination); if (ip->client->state != S_REQUESTING) memcpy(&from, ip->client->active->address.iabuf, sizeof(from)); else from.s_addr = INADDR_ANY; /* Record the number of seconds since we started sending. */ if (ip->client->state == S_REQUESTING) ip->client->packet.secs = ip->client->secs; else { if (interval < 65536) ip->client->packet.secs = htons(interval); else ip->client->packet.secs = htons(65535); } note("DHCPREQUEST on %s to %s port %d", ip->name, inet_ntoa(destination.sin_addr), ntohs(destination.sin_port)); if (destination.sin_addr.s_addr != INADDR_BROADCAST && fallback_interface) result = send_packet(fallback_interface, NULL, &ip->client->packet, ip->client->packet_length, from, &destination, NULL); else /* Send out a packet. */ result = send_packet(ip, NULL, &ip->client->packet, ip->client->packet_length, from, &destination, NULL); add_timeout(cur_time + ip->client->interval, send_request, ip); } void send_decline(void *ipp) { struct interface_info *ip = ipp; int result; note("DHCPDECLINE on %s to %s port %d", ip->name, inet_ntoa(sockaddr_broadcast.sin_addr), ntohs(sockaddr_broadcast.sin_port)); /* Send out a packet. */ result = send_packet(ip, NULL, &ip->client->packet, ip->client->packet_length, inaddr_any, &sockaddr_broadcast, NULL); } void send_release(void *ipp) { struct interface_info *ip = ipp; int result; note("DHCPRELEASE on %s to %s port %d", ip->name, inet_ntoa(sockaddr_broadcast.sin_addr), ntohs(sockaddr_broadcast.sin_port)); /* Send out a packet. */ result = send_packet(ip, NULL, &ip->client->packet, ip->client->packet_length, inaddr_any, &sockaddr_broadcast, NULL); } void make_discover(struct interface_info *ip, struct client_lease *lease) { unsigned char discover = DHCPDISCOVER; int i; struct tree_cache *options[256]; struct tree_cache option_elements[256]; memset(option_elements, 0, sizeof(option_elements)); memset(options, 0, sizeof(options)); memset(&ip->client->packet, 0, sizeof(ip->client->packet)); /* Set DHCP_MESSAGE_TYPE to DHCPDISCOVER */ i = DHO_DHCP_MESSAGE_TYPE; options[i] = &option_elements[i]; options[i]->value = &discover; options[i]->len = sizeof(discover); options[i]->buf_size = sizeof(discover); options[i]->timeout = 0xFFFFFFFF; options[i]->tree = NULL; /* Request the options we want */ i = DHO_DHCP_PARAMETER_REQUEST_LIST; options[i] = &option_elements[i]; options[i]->value = ip->client->config->requested_options; options[i]->len = ip->client->config->requested_option_count; options[i]->buf_size = ip->client->config->requested_option_count; options[i]->timeout = 0xFFFFFFFF; options[i]->tree = NULL; /* If we had an address, try to get it again. */ if (lease) { ip->client->requested_address = lease->address; i = DHO_DHCP_REQUESTED_ADDRESS; options[i] = &option_elements[i]; options[i]->value = lease->address.iabuf; options[i]->len = lease->address.len; options[i]->buf_size = lease->address.len; options[i]->timeout = 0xFFFFFFFF; options[i]->tree = NULL; } else ip->client->requested_address.len = 0; /* Send any options requested in the config file. */ for (i = 0; i < 256; i++) if (!options[i] && ip->client->config->send_options[i].data) { options[i] = &option_elements[i]; options[i]->value = ip->client->config->send_options[i].data; options[i]->len = ip->client->config->send_options[i].len; options[i]->buf_size = ip->client->config->send_options[i].len; options[i]->timeout = 0xFFFFFFFF; options[i]->tree = NULL; } /* Set up the option buffer... */ ip->client->packet_length = cons_options(NULL, &ip->client->packet, 0, options, 0, 0, 0, NULL, 0); if (ip->client->packet_length < BOOTP_MIN_LEN) ip->client->packet_length = BOOTP_MIN_LEN; ip->client->packet.op = BOOTREQUEST; ip->client->packet.htype = ip->hw_address.htype; ip->client->packet.hlen = ip->hw_address.hlen; ip->client->packet.hops = 0; ip->client->packet.xid = arc4random(); ip->client->packet.secs = 0; /* filled in by send_discover. */ if (can_receive_unicast_unconfigured(ip)) ip->client->packet.flags = 0; else ip->client->packet.flags = htons(BOOTP_BROADCAST); memset(&(ip->client->packet.ciaddr), 0, sizeof(ip->client->packet.ciaddr)); memset(&(ip->client->packet.yiaddr), 0, sizeof(ip->client->packet.yiaddr)); memset(&(ip->client->packet.siaddr), 0, sizeof(ip->client->packet.siaddr)); memset(&(ip->client->packet.giaddr), 0, sizeof(ip->client->packet.giaddr)); memcpy(ip->client->packet.chaddr, ip->hw_address.haddr, ip->hw_address.hlen); #ifdef DEBUG_PACKET dump_packet(sendpkt); dump_raw((unsigned char *)ip->client->packet, sendpkt->packet_length); #endif } void make_request(struct interface_info *ip, struct client_lease * lease) { unsigned char request = DHCPREQUEST; int i; struct tree_cache *options[256]; struct tree_cache option_elements[256]; memset(options, 0, sizeof(options)); memset(&ip->client->packet, 0, sizeof(ip->client->packet)); /* Set DHCP_MESSAGE_TYPE to DHCPREQUEST */ i = DHO_DHCP_MESSAGE_TYPE; options[i] = &option_elements[i]; options[i]->value = &request; options[i]->len = sizeof(request); options[i]->buf_size = sizeof(request); options[i]->timeout = 0xFFFFFFFF; options[i]->tree = NULL; /* Request the options we want */ i = DHO_DHCP_PARAMETER_REQUEST_LIST; options[i] = &option_elements[i]; options[i]->value = ip->client->config->requested_options; options[i]->len = ip->client->config->requested_option_count; options[i]->buf_size = ip->client->config->requested_option_count; options[i]->timeout = 0xFFFFFFFF; options[i]->tree = NULL; /* If we are requesting an address that hasn't yet been assigned to us, use the DHCP Requested Address option. */ if (ip->client->state == S_REQUESTING) { /* Send back the server identifier... */ i = DHO_DHCP_SERVER_IDENTIFIER; options[i] = &option_elements[i]; options[i]->value = lease->options[i].data; options[i]->len = lease->options[i].len; options[i]->buf_size = lease->options[i].len; options[i]->timeout = 0xFFFFFFFF; options[i]->tree = NULL; } if (ip->client->state == S_REQUESTING || ip->client->state == S_REBOOTING) { ip->client->requested_address = lease->address; i = DHO_DHCP_REQUESTED_ADDRESS; options[i] = &option_elements[i]; options[i]->value = lease->address.iabuf; options[i]->len = lease->address.len; options[i]->buf_size = lease->address.len; options[i]->timeout = 0xFFFFFFFF; options[i]->tree = NULL; } else ip->client->requested_address.len = 0; /* Send any options requested in the config file. */ for (i = 0; i < 256; i++) if (!options[i] && ip->client->config->send_options[i].data) { options[i] = &option_elements[i]; options[i]->value = ip->client->config->send_options[i].data; options[i]->len = ip->client->config->send_options[i].len; options[i]->buf_size = ip->client->config->send_options[i].len; options[i]->timeout = 0xFFFFFFFF; options[i]->tree = NULL; } /* Set up the option buffer... */ ip->client->packet_length = cons_options(NULL, &ip->client->packet, 0, options, 0, 0, 0, NULL, 0); if (ip->client->packet_length < BOOTP_MIN_LEN) ip->client->packet_length = BOOTP_MIN_LEN; ip->client->packet.op = BOOTREQUEST; ip->client->packet.htype = ip->hw_address.htype; ip->client->packet.hlen = ip->hw_address.hlen; ip->client->packet.hops = 0; ip->client->packet.xid = ip->client->xid; ip->client->packet.secs = 0; /* Filled in by send_request. */ /* If we own the address we're requesting, put it in ciaddr; otherwise set ciaddr to zero. */ if (ip->client->state == S_BOUND || ip->client->state == S_RENEWING || ip->client->state == S_REBINDING) { memcpy(&ip->client->packet.ciaddr, lease->address.iabuf, lease->address.len); ip->client->packet.flags = 0; } else { memset(&ip->client->packet.ciaddr, 0, sizeof(ip->client->packet.ciaddr)); if (can_receive_unicast_unconfigured(ip)) ip->client->packet.flags = 0; else ip->client->packet.flags = htons(BOOTP_BROADCAST); } memset(&ip->client->packet.yiaddr, 0, sizeof(ip->client->packet.yiaddr)); memset(&ip->client->packet.siaddr, 0, sizeof(ip->client->packet.siaddr)); memset(&ip->client->packet.giaddr, 0, sizeof(ip->client->packet.giaddr)); memcpy(ip->client->packet.chaddr, ip->hw_address.haddr, ip->hw_address.hlen); #ifdef DEBUG_PACKET dump_packet(sendpkt); dump_raw((unsigned char *)ip->client->packet, sendpkt->packet_length); #endif } void make_decline(struct interface_info *ip, struct client_lease *lease) { unsigned char decline = DHCPDECLINE; int i; struct tree_cache *options[256]; struct tree_cache message_type_tree; struct tree_cache requested_address_tree; struct tree_cache server_id_tree; struct tree_cache client_id_tree; memset(options, 0, sizeof(options)); memset(&ip->client->packet, 0, sizeof(ip->client->packet)); /* Set DHCP_MESSAGE_TYPE to DHCPDECLINE */ i = DHO_DHCP_MESSAGE_TYPE; options[i] = &message_type_tree; options[i]->value = &decline; options[i]->len = sizeof(decline); options[i]->buf_size = sizeof(decline); options[i]->timeout = 0xFFFFFFFF; options[i]->tree = NULL; /* Send back the server identifier... */ i = DHO_DHCP_SERVER_IDENTIFIER; options[i] = &server_id_tree; options[i]->value = lease->options[i].data; options[i]->len = lease->options[i].len; options[i]->buf_size = lease->options[i].len; options[i]->timeout = 0xFFFFFFFF; options[i]->tree = NULL; /* Send back the address we're declining. */ i = DHO_DHCP_REQUESTED_ADDRESS; options[i] = &requested_address_tree; options[i]->value = lease->address.iabuf; options[i]->len = lease->address.len; options[i]->buf_size = lease->address.len; options[i]->timeout = 0xFFFFFFFF; options[i]->tree = NULL; /* Send the uid if the user supplied one. */ i = DHO_DHCP_CLIENT_IDENTIFIER; if (ip->client->config->send_options[i].len) { options[i] = &client_id_tree; options[i]->value = ip->client->config->send_options[i].data; options[i]->len = ip->client->config->send_options[i].len; options[i]->buf_size = ip->client->config->send_options[i].len; options[i]->timeout = 0xFFFFFFFF; options[i]->tree = NULL; } /* Set up the option buffer... */ ip->client->packet_length = cons_options(NULL, &ip->client->packet, 0, options, 0, 0, 0, NULL, 0); if (ip->client->packet_length < BOOTP_MIN_LEN) ip->client->packet_length = BOOTP_MIN_LEN; ip->client->packet.op = BOOTREQUEST; ip->client->packet.htype = ip->hw_address.htype; ip->client->packet.hlen = ip->hw_address.hlen; ip->client->packet.hops = 0; ip->client->packet.xid = ip->client->xid; ip->client->packet.secs = 0; /* Filled in by send_request. */ ip->client->packet.flags = 0; /* ciaddr must always be zero. */ memset(&ip->client->packet.ciaddr, 0, sizeof(ip->client->packet.ciaddr)); memset(&ip->client->packet.yiaddr, 0, sizeof(ip->client->packet.yiaddr)); memset(&ip->client->packet.siaddr, 0, sizeof(ip->client->packet.siaddr)); memset(&ip->client->packet.giaddr, 0, sizeof(ip->client->packet.giaddr)); memcpy(ip->client->packet.chaddr, ip->hw_address.haddr, ip->hw_address.hlen); #ifdef DEBUG_PACKET dump_packet(sendpkt); dump_raw((unsigned char *)ip->client->packet, sendpkt->packet_length); #endif } void make_release(struct interface_info *ip, struct client_lease *lease) { unsigned char request = DHCPRELEASE; int i; struct tree_cache *options[256]; struct tree_cache message_type_tree; struct tree_cache server_id_tree; memset(options, 0, sizeof(options)); memset(&ip->client->packet, 0, sizeof(ip->client->packet)); /* Set DHCP_MESSAGE_TYPE to DHCPRELEASE */ i = DHO_DHCP_MESSAGE_TYPE; options[i] = &message_type_tree; options[i]->value = &request; options[i]->len = sizeof(request); options[i]->buf_size = sizeof(request); options[i]->timeout = 0xFFFFFFFF; options[i]->tree = NULL; /* Send back the server identifier... */ i = DHO_DHCP_SERVER_IDENTIFIER; options[i] = &server_id_tree; options[i]->value = lease->options[i].data; options[i]->len = lease->options[i].len; options[i]->buf_size = lease->options[i].len; options[i]->timeout = 0xFFFFFFFF; options[i]->tree = NULL; /* Set up the option buffer... */ ip->client->packet_length = cons_options(NULL, &ip->client->packet, 0, options, 0, 0, 0, NULL, 0); if (ip->client->packet_length < BOOTP_MIN_LEN) ip->client->packet_length = BOOTP_MIN_LEN; ip->client->packet.op = BOOTREQUEST; ip->client->packet.htype = ip->hw_address.htype; ip->client->packet.hlen = ip->hw_address.hlen; ip->client->packet.hops = 0; ip->client->packet.xid = random(); ip->client->packet.secs = 0; ip->client->packet.flags = 0; memset(&ip->client->packet.ciaddr, 0, sizeof(ip->client->packet.ciaddr)); memset(&ip->client->packet.yiaddr, 0, sizeof(ip->client->packet.yiaddr)); memset(&ip->client->packet.siaddr, 0, sizeof(ip->client->packet.siaddr)); memset(&ip->client->packet.giaddr, 0, sizeof(ip->client->packet.giaddr)); memcpy(ip->client->packet.chaddr, ip->hw_address.haddr, ip->hw_address.hlen); #ifdef DEBUG_PACKET dump_packet(sendpkt); dump_raw((unsigned char *)ip->client->packet, ip->client->packet_length); #endif } 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); } FILE *leaseFile; void rewrite_client_leases(void) { struct interface_info *ip; struct client_lease *lp; if (leaseFile) fclose(leaseFile); leaseFile = fopen(path_dhclient_db, "w"); if (!leaseFile) error("can't create %s: %m", path_dhclient_db); /* Write out all the leases attached to configured interfaces that we know about. */ for (ip = interfaces; ip; ip = ip->next) { for (lp = ip->client->leases; lp; lp = lp->next) write_client_lease(ip, lp, 1); if (ip->client->active) write_client_lease(ip, ip->client->active, 1); } /* Write out any leases that are attached to interfaces that aren't currently configured. */ for (ip = dummy_interfaces; ip; ip = ip->next) { for (lp = ip->client->leases; lp; lp = lp->next) write_client_lease(ip, lp, 1); if (ip->client->active) write_client_lease(ip, ip->client->active, 1); } fflush(leaseFile); } void write_client_lease(struct interface_info *ip, struct client_lease *lease, int rewrite) { int i; struct tm *t; static int leases_written; 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 */ leaseFile = fopen(path_dhclient_db, "w"); if (!leaseFile) error("can't create %s: %m", path_dhclient_db); } fprintf(leaseFile, "lease {\n"); if (lease->is_bootp) fprintf(leaseFile, " bootp;\n"); fprintf(leaseFile, " interface \"%s\";\n", ip->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); if (lease->medium) fprintf(leaseFile, " medium \"%s\";\n", lease->medium->string); 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)); /* Note: the following is not a Y2K bug - it's a Y1.9K bug. Until somebody invents a time machine, I think we can safely disregard it. */ 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); } /* Variables holding name of script and file pointer for writing to script. Needless to say, this is not reentrant - only one script can be invoked at a time. */ char scriptName[256]; FILE *scriptFile; void script_init(struct interface_info *ip, char *reason, struct string_list *medium) { if (ip) { ip->client->scriptEnvsize = 100; if (ip->client->scriptEnv == NULL) ip->client->scriptEnv = malloc(ip->client->scriptEnvsize * sizeof(char *)); if (ip->client->scriptEnv == NULL) error("script_init: no memory for environment"); ip->client->scriptEnv[0]=strdup(CLIENT_PATH); if (ip->client->scriptEnv[0] == NULL) error("script_init: no memory for environment"); ip->client->scriptEnv[1] = NULL; script_set_env(ip->client, "", "interface", ip->name); if (medium) script_set_env(ip->client, "", "medium", medium->string); script_set_env(ip->client, "", "reason", reason); } } void script_write_params(struct interface_info *ip, char *prefix, struct client_lease *lease) { int i; u_int8_t dbuf[1500]; int len = 0; char tbuf[128]; script_set_env(ip->client, prefix, "ip_address", piaddr(lease->address)); /* For the benefit of Linux (and operating systems which may have similar needs), compute the network address based on the supplied ip address and netmask, if provided. Also compute the broadcast address (the host address all ones broadcast address, not the host address all zeroes broadcast 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(ip->client, prefix, "network_number", piaddr(subnet)); if (!lease->options[DHO_BROADCAST_ADDRESS].len) { broadcast = broadcast_addr(subnet, netmask); if (broadcast.len) script_set_env(ip->client, prefix, "broadcast_address", piaddr(broadcast)); } } } if (lease->filename) script_set_env(ip->client, prefix, "filename", lease->filename); if (lease->server_name) script_set_env(ip->client, prefix, "server_name", lease->server_name); for (i = 0; i < 256; i++) { u_int8_t *dp = NULL; if (ip->client->config->defaults[i].len) { if (lease->options[i].len) { switch ( ip->client->config->default_actions[i]) { case ACTION_DEFAULT: dp = lease->options[i].data; len = lease->options[i].len; break; case ACTION_SUPERSEDE: supersede: dp = ip->client-> config->defaults[i].data; len = ip->client-> config->defaults[i].len; break; case ACTION_PREPEND: len = ip->client-> config->defaults[i].len + lease->options[i].len; if (len > sizeof(dbuf)) { warn("no space to %s %s", "prepend option", dhcp_options[i].name); goto supersede; } dp = dbuf; memcpy(dp, ip->client-> config->defaults[i].data, ip->client-> config->defaults[i].len); memcpy(dp + ip->client-> config->defaults[i].len, lease->options[i].data, lease->options[i].len); dp[len] = '\0'; break; case ACTION_APPEND: len = ip->client-> config->defaults[i].len + lease->options[i].len; if (len > sizeof(dbuf)) { warn("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, ip->client-> config->defaults[i].data, ip->client-> config->defaults[i].len); dp[len] = '\0'; } } else { dp = ip->client-> config->defaults[i].data; len = ip->client-> 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(ip->client, prefix, name, pretty_print_option(i, dp, len, 0, 0)); } } snprintf(tbuf, sizeof(tbuf), "%d", (int)lease->expiry); script_set_env(ip->client, prefix, "expiry", tbuf); } int script_go(struct interface_info *ip) { char *scriptName; char *argv[2]; char **envp; char *epp[3]; char reason[] = "REASON=NBI"; static char client_path[] = CLIENT_PATH; int pid, wpid, wstatus; if (ip) { scriptName = ip->client->config->script_name; envp = ip->client->scriptEnv; } else { scriptName = top_level_config.script_name; epp[0] = reason; epp[1] = client_path; epp[2] = NULL; envp = epp; } 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); exit(0); } if (ip) script_flush_env(ip->client); return (wstatus & 0xff); } void script_set_env(struct client_state *client, const char *prefix, const char *name, const char *value) { int i, 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"); snprintf(client->scriptEnv[i], strlen(prefix) + strlen(name) + 1 + strlen(value) + 1, "%s%s=%s", prefix, name, value); } void script_flush_env(struct client_state *client) { 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, 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; int pid; /* Don't become a daemon if the user requested otherwise. */ if (no_daemon) { write_client_pid_file(); return; } /* Only do it once. */ if (state) return; state = 1; /* Stop logging to stderr... */ log_perror = 0; /* Become a daemon... */ if ((pid = fork()) < 0) error("Can't fork daemon: %m"); else if (pid) exit(0); /* Become session leader and get pid... */ pid = setsid(); /* Close standard I/O descriptors. */ close(0); close(1); close(2); write_client_pid_file(); } void write_client_pid_file() { FILE *pf; int pfdesc; pfdesc = open(path_dhclient_pid, O_CREAT | O_TRUNC | O_WRONLY, 0644); if (pfdesc < 0) { warn("Can't create %s: %m", path_dhclient_pid); return; } pf = fdopen(pfdesc, "w"); if (!pf) warn("Can't fdopen %s: %m", path_dhclient_pid); else { fprintf(pf, "%ld\n", (long)getpid()); fclose(pf); } } 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_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_SWAP_SERVER : case DHO_BROADCAST_ADDRESS : case DHO_NIS_SERVERS : case DHO_NTP_SERVERS : case DHO_NETBIOS_NAME_SERVERS : case DHO_NETBIOS_DD_SERVER : case DHO_FONT_SERVERS : case DHO_DHCP_SERVER_IDENTIFIER : /* These should be a list of one or more IP addresses, * separated by spaces. If they aren't, this lease is not * valid. */ if (!ipv4addrs(opbuf)) { warn("Invalid IP address in option: %s", opbuf); return (0); } return (1) ; case DHO_HOST_NAME : case DHO_DOMAIN_NAME : case DHO_NIS_DOMAIN : /* This has to be a valid internet domain name */ if (!res_hnok(sbuf)) { warn("Bogus Host Name option %d: %s (%s)", option, sbuf, opbuf); return (0); } 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_ROUTER_SOLICITATION_ADDRESS : 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_REQUESTED_ADDRESS : 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_END : /* do nothing */ return (1); default: warn("unknown dhcp option value 0x%x", option); return (unknown_ok); } } int res_hnok(const char *dn) { int pch = PERIOD, ch = *dn++; while (ch != '\0') { int nch = *dn++; if (periodchar(ch)) { ; } else if (periodchar(pch)) { if (!borderchar(ch)) return (0); } else if (periodchar(nch) || nch == '\0') { if (!borderchar(ch)) return (0); } else { if (!middlechar(ch)) return (0); } 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 (periodchar(*buf) || digitchar(*buf)) buf++; if (*buf == '\0') return (count); while (*buf == ' ') buf++; } return (0); } /* Format the specified option as a string */ 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; /* Code should be between 0 and 255. */ if (code > 255) error("option_as_string: bad code %d\n", code); for (; dp < data + len; dp++) { if (!isascii(*dp) || !isprint(*dp)) { if (dp + 1 != data + len || *dp != 0) { snprintf(op, opleft, "\\%03o", *dp); op += 4; opleft -= 4; } } 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: warn("dhcp option too large"); return ""; }