/* $OpenBSD: dhclient.c,v 1.63 2005/02/06 17:10:13 krw Exp $ */ /*- * SPDX-License-Identifier: BSD-3-Clause * * 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 "dhcpd.h" #include "privsep.h" #include #include #include #include #include #ifndef _PATH_VAREMPTY #define _PATH_VAREMPTY "/var/empty" #endif #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 whitechar(c) ((c) == ' ' || (c) == '\t') #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" cap_channel_t *capsyslog; time_t cur_time; struct timespec time_now; static time_t default_lease_time = 43200; /* 12 hours... */ const char *path_dhclient_conf = _PATH_DHCLIENT_CONF; char *path_dhclient_db = NULL; int log_perror = 1; static int privfd; static int nullfd = -1; static char hostname[_POSIX_HOST_NAME_MAX + 1]; static struct iaddr iaddr_broadcast = { 4, { 255, 255, 255, 255 } }; static struct in_addr inaddr_any, inaddr_broadcast; static char *path_dhclient_pidfile; struct pidfh *pidfile; /* * ASSERT_STATE() does nothing now; it used to be * assert (state_is == state_shouldbe). */ #define ASSERT_STATE(state_is, state_shouldbe) {} /* * We need to check that the expiry, renewal and rebind times are not beyond * the end of time (~2038 when a 32-bit time_t is being used). */ #define TIME_MAX ((((time_t) 1 << (sizeof(time_t) * CHAR_BIT - 2)) - 1) * 2 + 1) static struct timespec arp_timeout = { .tv_sec = 0, .tv_nsec = 250 * 1000 * 1000 }; static const struct timespec zero_timespec = { .tv_sec = 0, .tv_nsec = 0 }; int log_priority; static int no_daemon; static int unknown_ok = 1; static int routefd; struct interface_info *ifi; int findproto(char *, int); struct sockaddr *get_ifa(char *, int); void routehandler(struct protocol *); void usage(void); int check_option(struct client_lease *l, int option); int check_classless_option(unsigned char *data, int len); int ipv4addrs(const char * buf); int res_hnok(const char *dn); int check_search(const char *srch); const char *option_as_string(unsigned int code, unsigned char *data, int len); int fork_privchld(int, int); #define ROUNDUP(a) \ ((a) > 0 ? (1 + (((a) - 1) | (sizeof(long) - 1))) : sizeof(long)) #define ADVANCE(x, n) (x += ROUNDUP((n)->sa_len)) /* Minimum MTU is 68 as per RFC791, p. 24 */ #define MIN_MTU 68 static time_t scripttime; int findproto(char *cp, int n) { struct sockaddr *sa; unsigned 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; unsigned 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); } static struct iaddr defaddr = { .len = 4 }; static uint8_t curbssid[6]; static void disassoc(void *arg) { struct interface_info *_ifi = arg; /* * Clear existing state. */ if (_ifi->client->active != NULL) { script_init("EXPIRE", NULL); script_write_params("old_", _ifi->client->active); if (_ifi->client->alias) script_write_params("alias_", _ifi->client->alias); script_go(); } _ifi->client->state = S_INIT; } void routehandler(struct protocol *p __unused) { char msg[2048], *addr; struct rt_msghdr *rtm; struct if_msghdr *ifm; struct ifa_msghdr *ifam; struct if_announcemsghdr *ifan; struct ieee80211_join_event *jev; struct client_lease *l; time_t t = time(NULL); struct sockaddr_in *sa; struct iaddr a; ssize_t n; int linkstat; n = read(routefd, &msg, sizeof(msg)); rtm = (struct rt_msghdr *)msg; if (n < (ssize_t)sizeof(rtm->rtm_msglen) || n < (ssize_t)rtm->rtm_msglen || rtm->rtm_version != RTM_VERSION) return; switch (rtm->rtm_type) { case RTM_NEWADDR: case RTM_DELADDR: ifam = (struct ifa_msghdr *)rtm; if (ifam->ifam_index != ifi->index) break; if (findproto((char *)(ifam + 1), ifam->ifam_addrs) != AF_INET) break; if (scripttime == 0 || t < scripttime + 10) break; sa = (struct sockaddr_in*)get_ifa((char *)(ifam + 1), ifam->ifam_addrs); if (sa == NULL) break; if ((a.len = sizeof(struct in_addr)) > sizeof(a.iabuf)) error("king bula sez: len mismatch"); memcpy(a.iabuf, &sa->sin_addr, a.len); if (addr_eq(a, defaddr)) break; for (l = ifi->client->active; l != NULL; l = l->next) if (addr_eq(a, l->address)) break; if (l == NULL) /* added/deleted addr is not the one we set */ break; addr = inet_ntoa(sa->sin_addr); if (rtm->rtm_type == RTM_NEWADDR) { /* * XXX: If someone other than us adds our address, * should we assume they are taking over from us, * delete the lease record, and exit without modifying * the interface? */ warning("My address (%s) was re-added", addr); } else { warning("My address (%s) was deleted, dhclient exiting", addr); goto die; } break; case RTM_IFINFO: ifm = (struct if_msghdr *)rtm; if (ifm->ifm_index != ifi->index) break; if ((rtm->rtm_flags & RTF_UP) == 0) { warning("Interface %s is down, dhclient exiting", ifi->name); goto die; } linkstat = interface_link_status(ifi->name); if (linkstat != ifi->linkstat) { debug("%s link state %s -> %s", ifi->name, ifi->linkstat ? "up" : "down", linkstat ? "up" : "down"); ifi->linkstat = linkstat; if (linkstat) state_reboot(ifi); } break; case RTM_IFANNOUNCE: ifan = (struct if_announcemsghdr *)rtm; if (ifan->ifan_what == IFAN_DEPARTURE && ifan->ifan_index == ifi->index) { warning("Interface %s is gone, dhclient exiting", ifi->name); goto die; } break; case RTM_IEEE80211: ifan = (struct if_announcemsghdr *)rtm; if (ifan->ifan_index != ifi->index) break; switch (ifan->ifan_what) { case RTM_IEEE80211_ASSOC: case RTM_IEEE80211_REASSOC: /* * Use assoc/reassoc event to kick state machine * in case we roam. Otherwise fall back to the * normal state machine just like a wired network. */ jev = (struct ieee80211_join_event *) &ifan[1]; if (memcmp(curbssid, jev->iev_addr, 6)) { disassoc(ifi); state_reboot(ifi); } memcpy(curbssid, jev->iev_addr, 6); break; } break; default: break; } return; die: script_init("FAIL", NULL); if (ifi->client->alias) script_write_params("alias_", ifi->client->alias); script_go(); if (pidfile != NULL) pidfile_remove(pidfile); exit(1); } static void init_casper(void) { cap_channel_t *casper; casper = cap_init(); if (casper == NULL) error("unable to start casper"); capsyslog = cap_service_open(casper, "system.syslog"); cap_close(casper); if (capsyslog == NULL) error("unable to open system.syslog service"); } int main(int argc, char *argv[]) { u_int capmode; int ch, fd, quiet = 0, i = 0; int pipe_fd[2]; int immediate_daemon = 0; struct passwd *pw; pid_t otherpid; cap_rights_t rights; init_casper(); /* Initially, log errors to stderr as well as to syslogd. */ cap_openlog(capsyslog, getprogname(), LOG_PID | LOG_NDELAY, DHCPD_LOG_FACILITY); cap_setlogmask(capsyslog, LOG_UPTO(LOG_DEBUG)); while ((ch = getopt(argc, argv, "bc:dl:np:qu")) != -1) switch (ch) { case 'b': immediate_daemon = 1; break; case 'c': path_dhclient_conf = optarg; break; case 'd': no_daemon = 1; break; case 'l': path_dhclient_db = optarg; break; case 'n': arp_timeout = zero_timespec; break; case 'p': path_dhclient_pidfile = optarg; break; case 'q': quiet = 1; break; case 'u': unknown_ok = 0; break; default: usage(); } argc -= optind; argv += optind; if (argc != 1) usage(); if (path_dhclient_pidfile == NULL) { asprintf(&path_dhclient_pidfile, "%s/dhclient/dhclient.%s.pid", _PATH_VARRUN, *argv); if (path_dhclient_pidfile == NULL) error("asprintf"); } pidfile = pidfile_open(path_dhclient_pidfile, 0644, &otherpid); if (pidfile == NULL) { if (errno == EEXIST) error("dhclient already running, pid: %d.", otherpid); if (errno == EAGAIN) error("dhclient already running."); warning("Cannot open or create pidfile: %m"); } if ((ifi = calloc(1, sizeof(struct interface_info))) == NULL) error("calloc"); if (strlcpy(ifi->name, argv[0], IFNAMSIZ) >= IFNAMSIZ) error("Interface name too long"); 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(); clock_gettime(CLOCK_MONOTONIC, &time_now); cur_time = time_now.tv_sec; inaddr_broadcast.s_addr = INADDR_BROADCAST; inaddr_any.s_addr = INADDR_ANY; read_client_conf(); /* The next bit is potentially very time-consuming, so write out the pidfile right away. We will write it out again with the correct pid after daemonizing. */ if (pidfile != NULL) pidfile_write(pidfile); if (!interface_link_status(ifi->name)) { fprintf(stderr, "%s: no link ...", ifi->name); fflush(stderr); sleep(1); while (!interface_link_status(ifi->name)) { fprintf(stderr, "."); fflush(stderr); if (++i > 10) { fprintf(stderr, " giving up\n"); exit(1); } sleep(1); } fprintf(stderr, " got link\n"); } ifi->linkstat = 1; if ((nullfd = open(_PATH_DEVNULL, O_RDWR, 0)) == -1) error("cannot open %s: %m", _PATH_DEVNULL); if ((pw = getpwnam("_dhcp")) == NULL) { warning("no such user: _dhcp, falling back to \"nobody\""); if ((pw = getpwnam("nobody")) == NULL) error("no such user: nobody"); } /* * Obtain hostname before entering capability mode - it won't be * possible then, as reading kern.hostname is not permitted. */ if (gethostname(hostname, sizeof(hostname)) < 0) hostname[0] = '\0'; priv_script_init("PREINIT", NULL); if (ifi->client->alias) priv_script_write_params("alias_", ifi->client->alias); priv_script_go(); /* set up the interface */ discover_interfaces(ifi); if (pipe(pipe_fd) == -1) error("pipe"); fork_privchld(pipe_fd[0], pipe_fd[1]); close(ifi->ufdesc); ifi->ufdesc = -1; close(ifi->wfdesc); ifi->wfdesc = -1; close(pipe_fd[0]); privfd = pipe_fd[1]; cap_rights_init(&rights, CAP_READ, CAP_WRITE); if (caph_rights_limit(privfd, &rights) < 0) error("can't limit private descriptor: %m"); 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(); rewrite_client_leases(); close(fd); if ((routefd = socket(PF_ROUTE, SOCK_RAW, 0)) != -1) add_protocol("AF_ROUTE", routefd, routehandler, ifi); if (shutdown(routefd, SHUT_WR) < 0) error("can't shutdown route socket: %m"); cap_rights_init(&rights, CAP_EVENT, CAP_READ); if (caph_rights_limit(routefd, &rights) < 0) error("can't limit route socket: %m"); endpwent(); setproctitle("%s", ifi->name); /* setgroups(2) is not permitted in capability mode. */ if (setgroups(1, &pw->pw_gid) != 0) error("can't restrict groups: %m"); if (caph_enter_casper() < 0) error("can't enter capability mode: %m"); /* * If we are not in capability mode (i.e., Capsicum or libcasper is * disabled), try to restrict filesystem access. This will fail if * kern.chroot_allow_open_directories is 0 or the process is jailed. */ if (cap_getmode(&capmode) < 0 || capmode == 0) { if (chroot(_PATH_VAREMPTY) == -1) error("chroot"); if (chdir("/") == -1) error("chdir(\"/\")"); } if (setegid(pw->pw_gid) || setgid(pw->pw_gid) || seteuid(pw->pw_uid) || setuid(pw->pw_uid)) error("can't drop privileges: %m"); if (immediate_daemon) go_daemon(); ifi->client->state = S_INIT; state_reboot(ifi); bootp_packet_handler = do_packet; dispatch(); /* not reached */ return (0); } void usage(void) { fprintf(stderr, "usage: %s [-bdnqu] ", getprogname()); fprintf(stderr, "[-c conffile] [-l leasefile] interface\n"); 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 *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 = arc4random(); /* 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("ARPCHECK", lp->medium); script_write_params("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()) { 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))) return; if (ip->client->state != S_REBOOTING && ip->client->state != S_REQUESTING && ip->client->state != S_RENEWING && ip->client->state != S_REBINDING) 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->config->default_actions[DHO_DHCP_LEASE_TIME] == ACTION_SUPERSEDE) ip->client->new->expiry = getULong( ip->client->config->defaults[DHO_DHCP_LEASE_TIME].data); else if (ip->client->new->options[DHO_DHCP_LEASE_TIME].len >= 4) 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. Also make sure that the addition of cur_time below does not overflow (a 32 bit) time_t. */ if (ip->client->new->expiry < 0 || ip->client->new->expiry > TIME_MAX - cur_time) ip->client->new->expiry = TIME_MAX - cur_time; /* XXX should be fixed by resetting the client state */ if (ip->client->new->expiry < 60) ip->client->new->expiry = 60; /* Unless overridden in the config, take the server-provided renewal * time if there is one. Otherwise figure it out according to the spec. * Also make sure the renewal time does not exceed the expiry time. */ if (ip->client->config->default_actions[DHO_DHCP_RENEWAL_TIME] == ACTION_SUPERSEDE) ip->client->new->renewal = getULong( ip->client->config->defaults[DHO_DHCP_RENEWAL_TIME].data); else if (ip->client->new->options[DHO_DHCP_RENEWAL_TIME].len >= 4) ip->client->new->renewal = getULong( ip->client->new->options[DHO_DHCP_RENEWAL_TIME].data); else ip->client->new->renewal = ip->client->new->expiry / 2; if (ip->client->new->renewal < 0 || ip->client->new->renewal > ip->client->new->expiry / 2) ip->client->new->renewal = ip->client->new->expiry / 2; /* Same deal with the rebind time. */ if (ip->client->config->default_actions[DHO_DHCP_REBINDING_TIME] == ACTION_SUPERSEDE) ip->client->new->rebind = getULong( ip->client->config->defaults[DHO_DHCP_REBINDING_TIME].data); else if (ip->client->new->options[DHO_DHCP_REBINDING_TIME].len >= 4) ip->client->new->rebind = getULong( ip->client->new->options[DHO_DHCP_REBINDING_TIME].data); else ip->client->new->rebind = ip->client->new->renewal / 4 * 7; if (ip->client->new->rebind < 0 || ip->client->new->rebind > ip->client->new->renewal / 4 * 7) ip->client->new->rebind = ip->client->new->renewal / 4 * 7; /* Convert the time offsets into seconds-since-the-epoch */ ip->client->new->expiry += cur_time; ip->client->new->renewal += cur_time; ip->client->new->rebind += cur_time; bind_lease(ip); } void bind_lease(struct interface_info *ip) { struct option_data *opt; /* Remember the medium. */ ip->client->new->medium = ip->client->medium; opt = &ip->client->new->options[DHO_INTERFACE_MTU]; if (opt->len == sizeof(u_int16_t)) { u_int16_t mtu = 0; u_int16_t old_mtu = 0; bool supersede = (ip->client->config->default_actions[DHO_INTERFACE_MTU] == ACTION_SUPERSEDE); if (supersede) mtu = getUShort(ip->client->config->defaults[DHO_INTERFACE_MTU].data); else mtu = be16dec(opt->data); if (ip->client->active) { opt = &ip->client->active->options[DHO_INTERFACE_MTU]; if (opt->len == sizeof(u_int16_t)) { old_mtu = be16dec(opt->data); } } if (mtu < MIN_MTU) { /* Treat 0 like a user intentionally doesn't want to change MTU and, * therefore, warning is not needed */ if (!supersede || mtu != 0) warning("mtu size %u < %d: ignored", (unsigned)mtu, MIN_MTU); } else if (ip->client->state != S_RENEWING || mtu != old_mtu) { interface_set_mtu_unpriv(privfd, mtu); } } /* Write out the new lease. */ write_client_lease(ip, ip->client->new, 0); /* Run the client script with the new parameters. */ script_init((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("old_", ip->client->active); script_write_params("new_", ip->client->new); if (ip->client->alias) script_write_params("alias_", ip->client->alias); script_go(); /* 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), (int)(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; u_int8_t *dp = NULL; int len; ASSERT_STATE(state, S_BOUND); /* T1 has expired. */ make_request(ip, ip->client->active); ip->client->xid = ip->client->packet.xid; if (ip->client->config->default_actions[DHO_DHCP_SERVER_IDENTIFIER] == ACTION_SUPERSEDE) { dp = ip->client->config->defaults[DHO_DHCP_SERVER_IDENTIFIER].data; len = ip->client->config->defaults[DHO_DHCP_SERVER_IDENTIFIER].len; } else { dp = ip->client->active->options[DHO_DHCP_SERVER_IDENTIFIER].data; len = ip->client->active->options[DHO_DHCP_SERVER_IDENTIFIER].len; } if (len == 4) { memcpy(ip->client->destination.iabuf, dp, len); ip->client->destination.len = len; } 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); } 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 *); const 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; struct timespec arp_timeout_needed; struct timespec stop_selecting = { .tv_sec = 0, .tv_nsec = 0 }; time_now.tv_sec = cur_time; time_now.tv_nsec = 0; const char *name = packet->options[DHO_DHCP_MESSAGE_TYPE].len ? "DHCPOFFER" : "BOOTREPLY"; /* 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))) 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("ARPSEND", lease->medium); script_write_params("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()) arp_timeout_needed = zero_timespec; else arp_timeout_needed = arp_timeout; /* Figure out when we're supposed to stop selecting. */ stop_selecting.tv_sec = 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. */ struct timespec interm_struct; timespecadd(&time_now, &arp_timeout_needed, &interm_struct); if (ip->client->offered_leases && timespeccmp(&interm_struct, &stop_selecting, >)) arp_timeout_needed = zero_timespec; /* 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. */ struct timespec time_left; timespecsub(&stop_selecting, &time_now, &time_left); if (timespeccmp(&time_left, &arp_timeout_needed, <)) { timespecadd(&time_now, &arp_timeout_needed, &stop_selecting); } /* If the selecting interval has expired, go immediately to state_selecting(). Otherwise, time out into state_selecting at the select interval. */ if (timespeccmp(&stop_selecting, &zero_timespec, <=)) state_selecting(ip); else { add_timeout_timespec(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 interface_info *ip = packet->interface; struct client_lease *lease; int i, j; 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 (packet->options[i].len) { int ignored = 0; for (j = 0; ip->client->config->ignored_options[j]; j++) if (i == ip->client->config->ignored_options[j]) { ignored = 1; break; } if (ignored) continue; lease->options[i].data = malloc(packet->options[i].len + 1); if (!lease->options[i].data) { warning("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 */ warning("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); lease->nextserver.len = sizeof(packet->raw->siaddr); memcpy(lease->nextserver.iabuf, &packet->raw->siaddr, lease->nextserver.len); /* If the server name was filled out, copy it. Do not attempt to validate the server name as a host name. RFC 2131 merely states that sname is NUL-terminated (which do do not assume) and that it is the server's host name. Since the ISC client and server allow arbitrary characters, we do as well. */ 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) { warning("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'; } /* 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) { warning("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))) return; if (ip->client->state != S_REBOOTING && ip->client->state != S_REQUESTING && ip->client->state != S_RENEWING && ip->client->state != S_REBINDING) 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 interval, 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("MEDIUM", ip->client->medium); if (script_go()) 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 += (arc4random() >> 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) + ((arc4random() >> 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(inaddr_broadcast), REMOTE_PORT, (int)ip->client->interval); /* Send out a packet. */ send_packet_unpriv(privfd, &ip->client->packet, ip->client->packet_length, inaddr_any, inaddr_broadcast); 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("TIMEOUT", ip->client->active->medium); script_write_params("new_", ip->client->active); if (ip->client->alias) script_write_params("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()) { if (cur_time < ip->client->active->renewal) { ip->client->state = S_BOUND; note("bound: renewal in %d seconds.", (int)(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. */ note("No working leases in persistent database - sleeping.\n"); script_init("FAIL", NULL); if (ip->client->alias) script_write_params("alias_", ip->client->alias); script_go(); 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; struct in_addr from, to; int interval; /* 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("MEDIUM", ip->client->active->medium); /* If the medium we chose won't fly, go to INIT state. */ if (script_go()) 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("EXPIRE", NULL); script_write_params("old_", ip->client->active); if (ip->client->alias) script_write_params("alias_", ip->client->alias); script_go(); /* Now do a preinit on the interface so that we can discover a new address. */ script_init("PREINIT", NULL); if (ip->client->alias) script_write_params("alias_", ip->client->alias); script_go(); 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 += ((arc4random() >> 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) + ((arc4random() >> 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. */ if (ip->client->state == S_REQUESTING || ip->client->state == S_REBOOTING || cur_time > ip->client->active->rebind) to.s_addr = INADDR_BROADCAST; else memcpy(&to.s_addr, ip->client->destination.iabuf, sizeof(to.s_addr)); if (ip->client->state != S_REQUESTING && ip->client->state != S_REBOOTING) 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(to), REMOTE_PORT); /* Send out a packet. */ send_packet_unpriv(privfd, &ip->client->packet, ip->client->packet_length, from, to); add_timeout(cur_time + ip->client->interval, send_request, ip); } void send_decline(void *ipp) { struct interface_info *ip = ipp; note("DHCPDECLINE on %s to %s port %d", ip->name, inet_ntoa(inaddr_broadcast), REMOTE_PORT); /* Send out a packet. */ send_packet_unpriv(privfd, &ip->client->packet, ip->client->packet_length, inaddr_any, inaddr_broadcast); } void make_discover(struct interface_info *ip, struct client_lease *lease) { unsigned char discover = DHCPDISCOVER; struct tree_cache *options[256]; struct tree_cache option_elements[256]; int i; 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; /* 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; /* 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; } 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; } /* send host name if not set via config file. */ if (!options[DHO_HOST_NAME]) { if (hostname[0] != '\0') { size_t len; char* posDot = strchr(hostname, '.'); if (posDot != NULL) len = posDot - hostname; else len = strlen(hostname); options[DHO_HOST_NAME] = &option_elements[DHO_HOST_NAME]; options[DHO_HOST_NAME]->value = hostname; options[DHO_HOST_NAME]->len = len; options[DHO_HOST_NAME]->buf_size = len; options[DHO_HOST_NAME]->timeout = 0xFFFFFFFF; } } /* set unique client identifier */ char client_ident[sizeof(ip->hw_address.haddr) + 1]; if (!options[DHO_DHCP_CLIENT_IDENTIFIER]) { int hwlen = (ip->hw_address.hlen < sizeof(client_ident)-1) ? ip->hw_address.hlen : sizeof(client_ident)-1; client_ident[0] = ip->hw_address.htype; memcpy(&client_ident[1], ip->hw_address.haddr, hwlen); options[DHO_DHCP_CLIENT_IDENTIFIER] = &option_elements[DHO_DHCP_CLIENT_IDENTIFIER]; options[DHO_DHCP_CLIENT_IDENTIFIER]->value = client_ident; options[DHO_DHCP_CLIENT_IDENTIFIER]->len = hwlen+1; options[DHO_DHCP_CLIENT_IDENTIFIER]->buf_size = hwlen+1; options[DHO_DHCP_CLIENT_IDENTIFIER]->timeout = 0xFFFFFFFF; } /* 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. */ 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); } void make_request(struct interface_info *ip, struct client_lease * lease) { unsigned char request = DHCPREQUEST; struct tree_cache *options[256]; struct tree_cache option_elements[256]; int i; 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; /* 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; /* 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; } 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; } 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; } /* send host name if not set via config file. */ if (!options[DHO_HOST_NAME]) { if (hostname[0] != '\0') { size_t len; char* posDot = strchr(hostname, '.'); if (posDot != NULL) len = posDot - hostname; else len = strlen(hostname); options[DHO_HOST_NAME] = &option_elements[DHO_HOST_NAME]; options[DHO_HOST_NAME]->value = hostname; options[DHO_HOST_NAME]->len = len; options[DHO_HOST_NAME]->buf_size = len; options[DHO_HOST_NAME]->timeout = 0xFFFFFFFF; } } /* set unique client identifier */ char client_ident[sizeof(ip->hw_address.haddr) + 1]; if (!options[DHO_DHCP_CLIENT_IDENTIFIER]) { int hwlen = (ip->hw_address.hlen < sizeof(client_ident)-1) ? ip->hw_address.hlen : sizeof(client_ident)-1; client_ident[0] = ip->hw_address.htype; memcpy(&client_ident[1], ip->hw_address.haddr, hwlen); options[DHO_DHCP_CLIENT_IDENTIFIER] = &option_elements[DHO_DHCP_CLIENT_IDENTIFIER]; options[DHO_DHCP_CLIENT_IDENTIFIER]->value = client_ident; options[DHO_DHCP_CLIENT_IDENTIFIER]->len = hwlen+1; options[DHO_DHCP_CLIENT_IDENTIFIER]->buf_size = hwlen+1; options[DHO_DHCP_CLIENT_IDENTIFIER]->timeout = 0xFFFFFFFF; } /* 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)); ip->client->packet.flags = 0; } 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); } void make_decline(struct interface_info *ip, struct client_lease *lease) { struct tree_cache *options[256], message_type_tree; struct tree_cache requested_address_tree; struct tree_cache server_id_tree, client_id_tree; unsigned char decline = DHCPDECLINE; int i; 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; /* 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; /* 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; /* 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; } /* 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); } 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); } static FILE *leaseFile; void rewrite_client_leases(void) { struct client_lease *lp; cap_rights_t rights; if (!leaseFile) { leaseFile = fopen(path_dhclient_db, "w"); if (!leaseFile) error("can't create %s: %m", path_dhclient_db); cap_rights_init(&rights, CAP_FCNTL, CAP_FSTAT, CAP_FSYNC, CAP_FTRUNCATE, CAP_SEEK, CAP_WRITE); if (caph_rights_limit(fileno(leaseFile), &rights) < 0) { error("can't limit lease descriptor: %m"); } if (caph_fcntls_limit(fileno(leaseFile), CAP_FCNTL_GETFL) < 0) { error("can't limit lease descriptor fcntls: %m"); } } else { fflush(leaseFile); rewind(leaseFile); } for (lp = ifi->client->leases; lp; lp = lp->next) write_client_lease(ifi, lp, 1); if (ifi->client->active) write_client_lease(ifi, ifi->client->active, 1); fflush(leaseFile); ftruncate(fileno(leaseFile), ftello(leaseFile)); fsync(fileno(leaseFile)); } void write_client_lease(struct interface_info *ip, 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 */ 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->nextserver.len == sizeof(inaddr_any) && 0 != memcmp(lease->nextserver.iabuf, &inaddr_any, sizeof(inaddr_any))) fprintf(leaseFile, " next-server %s;\n", piaddr(lease->nextserver)); 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)); 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(const char *reason, struct string_list *medium) { size_t len, mediumlen = 0; struct imsg_hdr hdr; struct buf *buf; int errs; if (medium != NULL && medium->string != NULL) mediumlen = strlen(medium->string); hdr.code = IMSG_SCRIPT_INIT; hdr.len = sizeof(struct imsg_hdr) + sizeof(size_t) + mediumlen + sizeof(size_t) + strlen(reason); if ((buf = buf_open(hdr.len)) == NULL) error("buf_open: %m"); errs = 0; errs += buf_add(buf, &hdr, sizeof(hdr)); errs += buf_add(buf, &mediumlen, sizeof(mediumlen)); if (mediumlen > 0) errs += buf_add(buf, medium->string, mediumlen); len = strlen(reason); errs += buf_add(buf, &len, sizeof(len)); errs += buf_add(buf, reason, len); if (errs) error("buf_add: %m"); if (buf_close(privfd, buf) == -1) error("buf_close: %m"); } void priv_script_init(const char *reason, char *medium) { struct interface_info *ip = ifi; 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); script_set_env(ip->client, "", "reason", reason); } } void priv_script_write_params(const char *prefix, struct client_lease *lease) { struct interface_info *ip = ifi; u_int8_t dbuf[1500], *dp = NULL; int i; size_t len; char tbuf[128]; script_set_env(ip->client, prefix, "ip_address", piaddr(lease->address)); if (ip->client->config->default_actions[DHO_SUBNET_MASK] == ACTION_SUPERSEDE) { dp = ip->client->config->defaults[DHO_SUBNET_MASK].data; len = ip->client->config->defaults[DHO_SUBNET_MASK].len; } else { dp = lease->options[DHO_SUBNET_MASK].data; len = lease->options[DHO_SUBNET_MASK].len; } if (len && (len < sizeof(lease->address.iabuf))) { struct iaddr netmask, subnet, broadcast; memcpy(netmask.iabuf, dp, len); netmask.len = 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++) { len = 0; 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)) { warning("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: /* * When we append, we assume that we're * appending to text. Some MS servers * include a NUL byte at the end of * the search string provided. */ len = ip->client-> 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; } memcpy(dbuf, lease->options[i].data, lease->options[i].len); for (dp = dbuf + lease->options[i].len; dp > dbuf; dp--, len--) if (dp[-1] != '\0') break; memcpy(dp, ip->client-> config->defaults[i].data, ip->client-> config->defaults[i].len); dp = dbuf; 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); } void script_write_params(const 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 errs, 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(*lease) + sizeof(fn_len) + fn_len + sizeof(sn_len) + sn_len + sizeof(pr_len) + pr_len; for (i = 0; i < 256; i++) { hdr.len += sizeof(lease->options[i].len); hdr.len += lease->options[i].len; } scripttime = time(NULL); if ((buf = buf_open(hdr.len)) == NULL) error("buf_open: %m"); errs = 0; errs += buf_add(buf, &hdr, sizeof(hdr)); errs += buf_add(buf, lease, sizeof(*lease)); errs += buf_add(buf, &fn_len, sizeof(fn_len)); errs += buf_add(buf, lease->filename, fn_len); errs += buf_add(buf, &sn_len, sizeof(sn_len)); errs += buf_add(buf, lease->server_name, sn_len); errs += buf_add(buf, &pr_len, sizeof(pr_len)); errs += buf_add(buf, prefix, pr_len); for (i = 0; i < 256; i++) { errs += buf_add(buf, &lease->options[i].len, sizeof(lease->options[i].len)); errs += buf_add(buf, lease->options[i].data, lease->options[i].len); } if (errs) error("buf_add: %m"); if (buf_close(privfd, buf) == -1) error("buf_close: %m"); } int script_go(void) { struct imsg_hdr hdr; struct buf *buf; int ret; hdr.code = IMSG_SCRIPT_GO; hdr.len = sizeof(struct imsg_hdr); if ((buf = buf_open(hdr.len)) == NULL) error("buf_open: %m"); if (buf_add(buf, &hdr, sizeof(hdr))) error("buf_add: %m"); if (buf_close(privfd, buf) == -1) error("buf_close: %m"); 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)); scripttime = time(NULL); return (ret); } int priv_script_go(void) { char *scriptName, *argv[2], **envp, *epp[3], reason[] = "REASON=NBI"; static char client_path[] = CLIENT_PATH; struct interface_info *ip = ifi; int pid, wpid, wstatus; scripttime = time(NULL); 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); } if (ip) script_flush_env(ip->client); return (WIFEXITED(wstatus) ? WEXITSTATUS(wstatus) : 128 + WTERMSIG(wstatus)); } void script_set_env(struct client_state *client, const char *prefix, const char *name, const char *value) { int i, namelen; size_t j; /* No `` or $() command substitution allowed in environment values! */ for (j=0; j < strlen(value); j++) switch (value[j]) { case '`': case '$': warning("illegal character (%c) in value '%s'", value[j], value); /* Ignore this option */ return; } 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) { size_t 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; cap_rights_t rights; if (no_daemon || state) return; state = 1; /* Stop logging to stderr... */ log_perror = 0; if (daemonfd(-1, nullfd) == -1) error("daemon"); cap_rights_init(&rights); if (pidfile != NULL) { pidfile_write(pidfile); if (caph_rights_limit(pidfile_fileno(pidfile), &rights) < 0) error("can't limit pidfile descriptor: %m"); } if (nullfd != -1) { close(nullfd); nullfd = -1; } if (caph_rights_limit(STDIN_FILENO, &rights) < 0) error("can't limit stdin: %m"); cap_rights_init(&rights, CAP_WRITE); if (caph_rights_limit(STDOUT_FILENO, &rights) < 0) error("can't limit stdout: %m"); if (caph_rights_limit(STDERR_FILENO, &rights) < 0) error("can't limit stderr: %m"); } int check_option(struct client_lease *l, int option) { const char *opbuf; const 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: case DHO_NISPLUS_SERVERS: case DHO_MOBILE_IP_HOME_AGENT: case DHO_SMTP_SERVER: case DHO_POP_SERVER: case DHO_NNTP_SERVER: case DHO_WWW_SERVER: case DHO_FINGER_SERVER: case DHO_IRC_SERVER: case DHO_STREETTALK_SERVER: case DHO_STREETTALK_DA_SERVER: if (!ipv4addrs(opbuf)) { warning("Invalid IP address in option: %s", opbuf); return (0); } return (1) ; case DHO_HOST_NAME: case DHO_NIS_DOMAIN: case DHO_NISPLUS_DOMAIN: case DHO_TFTP_SERVER_NAME: 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_DOMAIN_NAME: case DHO_DOMAIN_SEARCH: if (!res_hnok(sbuf)) { if (!check_search(sbuf)) { warning("Bogus domain search list %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_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_BOOTFILE_NAME: case DHO_DHCP_USER_CLASS_ID: case DHO_URL: case DHO_SIP_SERVERS: case DHO_V_I_VENDOR_CLASS: case DHO_V_I_VENDOR_OPTS: case DHO_END: return (1); case DHO_CLASSLESS_ROUTES: return (check_classless_option(l->options[option].data, l->options[option].len)); default: warning("unknown dhcp option value 0x%x", option); return (unknown_ok); } } /* RFC 3442 The Classless Static Routes option checks */ int check_classless_option(unsigned char *data, int len) { int i = 0; unsigned char width; in_addr_t addr, mask; if (len < 5) { warning("Too small length: %d", len); return (0); } while(i < len) { width = data[i++]; if (width == 0) { i += 4; continue; } else if (width < 9) { addr = (in_addr_t)(data[i] << 24); i += 1; } else if (width < 17) { addr = (in_addr_t)(data[i] << 24) + (in_addr_t)(data[i + 1] << 16); i += 2; } else if (width < 25) { addr = (in_addr_t)(data[i] << 24) + (in_addr_t)(data[i + 1] << 16) + (in_addr_t)(data[i + 2] << 8); i += 3; } else if (width < 33) { addr = (in_addr_t)(data[i] << 24) + (in_addr_t)(data[i + 1] << 16) + (in_addr_t)(data[i + 2] << 8) + data[i + 3]; i += 4; } else { warning("Incorrect subnet width: %d", width); return (0); } mask = (in_addr_t)(~0) << (32 - width); addr = ntohl(addr); mask = ntohl(mask); /* * From RFC 3442: * ... After deriving a subnet number and subnet mask * from each destination descriptor, the DHCP client * MUST zero any bits in the subnet number where the * corresponding bit in the mask is zero... */ if ((addr & mask) != addr) { addr &= mask; data[i - 1] = (unsigned char)( (addr >> (((32 - width)/8)*8)) & 0xFF); } i += 4; } if (i > len) { warning("Incorrect data length: %d (must be %d)", len, i); return (0); } return (1); } 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); } int check_search(const char *srch) { int pch = PERIOD, ch = *srch++; int domains = 1; /* 256 char limit re resolv.conf(5) */ if (strlen(srch) > 256) return (0); while (whitechar(ch)) ch = *srch++; while (ch != '\0') { int nch = *srch++; if (periodchar(ch) || whitechar(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); } if (!whitechar(ch)) { pch = ch; } else { while (whitechar(nch)) { nch = *srch++; } if (nch != '\0') domains++; pch = PERIOD; } ch = nch; } /* 6 domain limit re resolv.conf(5) */ if (domains > 6) return (0); return (1); } /* Does buf consist only of dotted decimal ipv4 addrs? * return how many if so, * otherwise, return 0 */ int ipv4addrs(const 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); } const 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) { 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: 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"); case 0: break; default: return (0); } setproctitle("%s [priv]", ifi->name); setsid(); dup2(nullfd, STDIN_FILENO); dup2(nullfd, STDOUT_FILENO); dup2(nullfd, STDERR_FILENO); close(nullfd); close(fd2); close(ifi->rfdesc); ifi->rfdesc = -1; 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(ifi, fd); } }