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freebsd-nq/sbin/dhclient/dhclient.c
Brooks Davis 59eac186e2 Avoid a null pointer dereference by not expiring our lease if we don't 
have an active one.

Submitted by:	sam
Reported by:	James Snow <snow at teardrop dot org>
Approved by:	re (dhclient blanket)
2005-06-13 23:43:08 +00:00

2416 lines
65 KiB
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/* $OpenBSD: dhclient.c,v 1.63 2005/02/06 17:10:13 krw Exp $ */
/* $FreeBSD$ */
/*
* Copyright 2004 Henning Brauer <henning@openbsd.org>
* 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 <mellon@fugue.com> 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"
#include "privsep.h"
#include <net80211/ieee80211_freebsd.h>
#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 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_t cur_time;
time_t default_lease_time = 43200; /* 12 hours... */
char *path_dhclient_conf = _PATH_DHCLIENT_CONF;
char *path_dhclient_db = NULL;
int log_perror = 1;
int privfd;
int nullfd = -1;
struct iaddr iaddr_broadcast = { 4, { 255, 255, 255, 255 } };
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) {}
#define TIME_MAX 2147483647
int log_priority;
int no_daemon;
int unknown_ok = 1;
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 ipv4addrs(char * buf);
int res_hnok(const char *dn);
char *option_as_string(unsigned int code, unsigned char *data, int len);
int fork_privchld(int, int);
#define ROUNDUP(a) \
((a) > 0 ? (1 + (((a) - 1) | (sizeof(long) - 1))) : sizeof(long))
#define ADVANCE(x, n) (x += ROUNDUP((n)->sa_len))
time_t scripttime;
int
findproto(char *cp, int n)
{
struct sockaddr *sa;
int i;
if (n == 0)
return -1;
for (i = 1; i; i <<= 1) {
if (i & n) {
sa = (struct sockaddr *)cp;
switch (i) {
case RTA_IFA:
case RTA_DST:
case RTA_GATEWAY:
case RTA_NETMASK:
if (sa->sa_family == AF_INET)
return AF_INET;
if (sa->sa_family == AF_INET6)
return AF_INET6;
break;
case RTA_IFP:
break;
}
ADVANCE(cp, sa);
}
}
return (-1);
}
struct sockaddr *
get_ifa(char *cp, int n)
{
struct sockaddr *sa;
int i;
if (n == 0)
return (NULL);
for (i = 1; i; i <<= 1)
if (i & n) {
sa = (struct sockaddr *)cp;
if (i == RTA_IFA)
return (sa);
ADVANCE(cp, sa);
}
return (NULL);
}
struct iaddr defaddr = { 4 };
/* ARGSUSED */
void
routehandler(struct protocol *p)
{
char msg[2048];
struct rt_msghdr *rtm;
struct if_msghdr *ifm;
struct ifa_msghdr *ifam;
struct if_announcemsghdr *ifan;
struct client_lease *l;
time_t t = time(NULL);
struct sockaddr *sa;
struct iaddr a;
ssize_t n;
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 (ifam->ifam_index != ifi->index)
break;
if (findproto((char *)(ifam + 1), ifam->ifam_addrs) != AF_INET)
break;
if (ifi == NULL)
goto die;
sa = get_ifa((char *)(ifam + 1), ifam->ifam_addrs);
if (sa == NULL)
goto die;
if ((a.len = sizeof(struct in_addr)) > sizeof(a.iabuf))
error("king bula sez: len mismatch");
memcpy(a.iabuf, &((struct sockaddr_in *)sa)->sin_addr, a.len);
if (addr_eq(a, defaddr))
break;
for (l = ifi->client->active; l != NULL; l = l->next)
if (addr_eq(a, l->address))
break;
if (l != NULL) /* new addr is the one we set */
break;
goto die;
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;
goto die;
case RTM_IFINFO:
ifm = (struct if_msghdr *)rtm;
if (ifm->ifm_index != ifi->index)
break;
if ((rtm->rtm_flags & RTF_UP) == 0)
goto die;
break;
case RTM_IFANNOUNCE:
ifan = (struct if_announcemsghdr *)rtm;
if (ifan->ifan_what == IFAN_DEPARTURE &&
ifan->ifan_index == ifi->index)
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:
state_reboot(ifi);
break;
case RTM_IEEE80211_DISASSOC:
/*
* Clear existing state; transition to the init
* state and then wait for either a link down
* notification or an associate event.
*/
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;
break;
}
break;
default:
break;
}
return;
die:
script_init("FAIL", NULL);
if (ifi->client->alias)
script_write_params("alias_", ifi->client->alias);
script_go();
exit(1);
}
int
main(int argc, char *argv[])
{
extern char *__progname;
int ch, fd, quiet = 0, i = 0;
int pipe_fd[2];
int immediate_daemon = 0;
struct passwd *pw;
/* Initially, log errors to stderr as well as to syslogd. */
openlog(__progname, LOG_PID | LOG_NDELAY, DHCPD_LOG_FACILITY);
setlogmask(LOG_UPTO(LOG_INFO));
while ((ch = getopt(argc, argv, "bc:dl:nqu")) != -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 'q':
quiet = 1;
break;
case 'u':
unknown_ok = 0;
break;
default:
usage();
}
argc -= optind;
argv += optind;
if (argc != 1)
usage();
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();
time(&cur_time);
memset(&sockaddr_broadcast, 0, sizeof(sockaddr_broadcast));
sockaddr_broadcast.sin_family = AF_INET;
sockaddr_broadcast.sin_port = htons(REMOTE_PORT);
sockaddr_broadcast.sin_addr.s_addr = INADDR_BROADCAST;
sockaddr_broadcast.sin_len = sizeof(sockaddr_broadcast);
inaddr_any.s_addr = INADDR_ANY;
read_client_conf();
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");
}
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");
}
if (pipe(pipe_fd) == -1)
error("pipe");
fork_privchld(pipe_fd[0], pipe_fd[1]);
close(pipe_fd[0]);
privfd = pipe_fd[1];
if ((fd = open(path_dhclient_db, O_RDONLY|O_EXLOCK|O_CREAT, 0)) == -1)
error("can't open and lock %s: %m", path_dhclient_db);
read_client_leases();
rewrite_client_leases();
close(fd);
priv_script_init("PREINIT", NULL);
if (ifi->client->alias)
priv_script_write_params("alias_", ifi->client->alias);
priv_script_go();
if ((routefd = socket(PF_ROUTE, SOCK_RAW, 0)) != -1)
add_protocol("AF_ROUTE", routefd, routehandler, ifi);
/* set up the interface */
discover_interfaces(ifi);
if (chroot(_PATH_VAREMPTY) == -1)
error("chroot");
if (chdir("/") == -1)
error("chdir(\"/\")");
if (setgroups(1, &pw->pw_gid) ||
setegid(pw->pw_gid) || setgid(pw->pw_gid) ||
seteuid(pw->pw_uid) || setuid(pw->pw_uid))
error("can't drop privileges: %m");
endpwent();
setproctitle("%s", ifi->name);
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)
{
extern char *__progname;
fprintf(stderr, "usage: %s [-dqu] ", __progname);
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->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;
/* XXX should be fixed by resetting the client state */
if (ip->client->new->expiry < 60)
ip->client->new->expiry = 60;
/* 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->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;
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);
}
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";
/* 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 = 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) {
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) {
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);
/* 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) {
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';
if (!res_hnok(lease->server_name) ) {
warning("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) {
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(sockaddr_broadcast.sin_addr),
ntohs(sockaddr_broadcast.sin_port),
(int)ip->client->interval);
/* Send out a packet. */
(void)send_packet(ip, &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("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 sockaddr_in destination;
struct in_addr from;
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. */
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 = htons(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));
/* Send out a packet. */
(void) send_packet(ip, &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;
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. */
(void) send_packet(ip, &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;
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;
}
/* 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;
}
/* 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);
}
FILE *leaseFile;
void
rewrite_client_leases(void)
{
struct client_lease *lp;
if (!leaseFile) {
leaseFile = fopen(path_dhclient_db, "w");
if (!leaseFile)
error("can't create %s: %m", path_dhclient_db);
} 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->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(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(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(char *prefix, struct client_lease *lease)
{
struct interface_info *ip = ifi;
u_int8_t dbuf[1500];
int i, len = 0;
char tbuf[128];
script_set_env(ip->client, prefix, "ip_address",
piaddr(lease->address));
if (lease->options[DHO_SUBNET_MASK].len &&
(lease->options[DHO_SUBNET_MASK].len <
sizeof(lease->address.iabuf))) {
struct iaddr netmask, subnet, broadcast;
memcpy(netmask.iabuf, lease->options[DHO_SUBNET_MASK].data,
lease->options[DHO_SUBNET_MASK].len);
netmask.len = lease->options[DHO_SUBNET_MASK].len;
subnet = subnet_number(lease->address, netmask);
if (subnet.len) {
script_set_env(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)) {
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:
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;
}
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);
}
void
script_write_params(char *prefix, struct client_lease *lease)
{
size_t fn_len = 0, sn_len = 0, pr_len = 0;
struct imsg_hdr hdr;
struct buf *buf;
int 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(struct client_lease) +
sizeof(size_t) + fn_len + sizeof(size_t) + sn_len +
sizeof(size_t) + pr_len;
for (i = 0; i < 256; i++)
hdr.len += sizeof(int) + lease->options[i].len;
scripttime = time(NULL);
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(struct client_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;
scripttime = time(NULL);
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));
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 (wstatus & 0xff);
}
void
script_set_env(struct client_state *client, const char *prefix,
const char *name, const char *value)
{
int i, j, namelen;
namelen = strlen(name);
for (i = 0; client->scriptEnv[i]; i++)
if (strncmp(client->scriptEnv[i], name, namelen) == 0 &&
client->scriptEnv[i][namelen] == '=')
break;
if (client->scriptEnv[i])
/* Reuse the slot. */
free(client->scriptEnv[i]);
else {
/* New variable. Expand if necessary. */
if (i >= client->scriptEnvsize - 1) {
char **newscriptEnv;
int newscriptEnvsize = client->scriptEnvsize + 50;
newscriptEnv = realloc(client->scriptEnv,
newscriptEnvsize);
if (newscriptEnv == NULL) {
free(client->scriptEnv);
client->scriptEnv = NULL;
client->scriptEnvsize = 0;
error("script_set_env: no memory for variable");
}
client->scriptEnv = newscriptEnv;
client->scriptEnvsize = newscriptEnvsize;
}
/* need to set the NULL pointer at end of array beyond
the new slot. */
client->scriptEnv[i + 1] = NULL;
}
/* Allocate space and format the variable in the appropriate slot. */
client->scriptEnv[i] = malloc(strlen(prefix) + strlen(name) + 1 +
strlen(value) + 1);
if (client->scriptEnv[i] == NULL)
error("script_set_env: no memory for variable assignment");
/* No `` or $() command substitution allowed in environment values! */
for (j=0; j < strlen(value); j++)
switch (value[j]) {
case '`':
case '$':
error("illegal character (%c) in value '%s'", value[j],
value);
/* not reached */
}
snprintf(client->scriptEnv[i], strlen(prefix) + strlen(name) +
1 + strlen(value) + 1, "%s%s=%s", prefix, name, value);
}
void
script_flush_env(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;
if (no_daemon || state)
return;
state = 1;
/* Stop logging to stderr... */
log_perror = 0;
if (daemon(1, 0) == -1)
error("daemon");
/* we are chrooted, daemon(3) fails to open /dev/null */
if (nullfd != -1) {
dup2(nullfd, STDIN_FILENO);
dup2(nullfd, STDOUT_FILENO);
dup2(nullfd, STDERR_FILENO);
close(nullfd);
nullfd = -1;
}
}
int
check_option(struct client_lease *l, int option)
{
char *opbuf;
char *sbuf;
/* we use this, since this is what gets passed to dhclient-script */
opbuf = pretty_print_option(option, l->options[option].data,
l->options[option].len, 0, 0);
sbuf = option_as_string(option, l->options[option].data,
l->options[option].len);
switch (option) {
case DHO_SUBNET_MASK:
case DHO_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:
if (!ipv4addrs(opbuf)) {
warning("Invalid IP address in option: %s", opbuf);
return (0);
}
return (1) ;
case DHO_HOST_NAME:
case DHO_DOMAIN_NAME:
case DHO_NIS_DOMAIN:
if (!res_hnok(sbuf)) {
warning("Bogus Host Name option %d: %s (%s)", option,
sbuf, opbuf);
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:
return (1);
default:
warning("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);
}
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 "<error>";
}
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);
dup2(nullfd, STDIN_FILENO);
dup2(nullfd, STDOUT_FILENO);
dup2(nullfd, STDERR_FILENO);
close(nullfd);
close(fd2);
for (;;) {
pfd[0].fd = fd;
pfd[0].events = POLLIN;
if ((nfds = poll(pfd, 1, INFTIM)) == -1)
if (errno != EINTR)
error("poll error");
if (nfds == 0 || !(pfd[0].revents & POLLIN))
continue;
dispatch_imsg(fd);
}
}
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