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Feature #7416 ยป dhclient.c

Fabian Kurtz, 03/21/2017 08:53 AM

 
/* $OpenBSD: dhclient.c,v 1.63 2005/02/06 17:10:13 krw Exp $ */

/*
* 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 <sys/cdefs.h>
__FBSDID("$FreeBSD$");

#include <sys/capsicum.h>

#include "dhcpd.h"
#include "privsep.h"

#include <sys/capsicum.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 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"

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;

char hostname[_POSIX_HOST_NAME_MAX + 1];

struct iaddr iaddr_broadcast = { 4, { 255, 255, 255, 255 } };
struct in_addr inaddr_any, inaddr_broadcast;

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) {}

#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 check_classless_option(unsigned char *data, int len);
int ipv4addrs(char * buf);
int res_hnok(const char *dn);
int check_search(const char *srch);
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))

static 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 };
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;
}

/* ARGSUSED */
void
routehandler(struct protocol *p)
{
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 *sa;
struct iaddr a;
ssize_t n;
int linkstat;

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:
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 = 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, &((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) /* added/deleted addr is not the one we set */
break;

addr = inet_ntoa(((struct sockaddr_in *)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);
}

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;
pid_t otherpid;
cap_rights_t rights;

/* Initially, log errors to stderr as well as to syslogd. */
openlog(__progname, LOG_PID | LOG_NDELAY, DHCPD_LOG_FACILITY);
setlogmask(LOG_UPTO(LOG_DEBUG));

while ((ch = getopt(argc, argv, "bc:dl:p: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 '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,
"%sdhclient.%s.pid", _PATH_VARRUN, *argv);
if (path_dhclient_pidfile == NULL)
error("asprintf");
}
pidfile = pidfile_open(path_dhclient_pidfile, 0600, &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();
time(&cur_time);

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 (cap_rights_limit(privfd, &rights) < 0 && errno != ENOSYS)
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 (cap_rights_limit(routefd, &rights) < 0 && errno != ENOSYS)
error("can't limit route socket: %m");

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 (cap_enter() < 0 && errno != ENOSYS)
error("can't enter capability mode: %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)
{
extern char *__progname;

fprintf(stderr, "usage: %s [-bdqu] ", __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;

/* Start of the updated section. */
if (ip->client->config->default_actions[DHO_DHCP_SERVER_IDENTIFIER] == ACTION_SUPERSEDE) {
memcpy(ip->client->destination.iabuf, ip->client->config->defaults[DHO_DHCP_SERVER_IDENTIFIER].data, 4);
ip->client->config->defaults[DHO_DHCP_SERVER_IDENTIFIER].len = 4;
} else 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;
/* End of the updated section */
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);

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)
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(struct hardware)];
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(struct hardware)];
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);
}

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 (cap_rights_limit(fileno(leaseFile), &rights) < 0 &&
errno != ENOSYS) {
error("can't limit lease descriptor: %m");
}
if (cap_fcntls_limit(fileno(leaseFile), CAP_FCNTL_GETFL) < 0 &&
errno != ENOSYS) {
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(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], *dp = NULL;
int i, 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(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;

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 (wstatus & 0xff);
}

void
script_set_env(struct client_state *client, const char *prefix,
const char *name, const char *value)
{
int i, j, namelen;

/* 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)
{
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;
cap_rights_t rights;

if (no_daemon || state)
return;

state = 1;

/* Stop logging to stderr... */
log_perror = 0;

if (daemon(1, 0) == -1)
error("daemon");

cap_rights_init(&rights);

if (pidfile != NULL) {
pidfile_write(pidfile);
if (cap_rights_limit(pidfile_fileno(pidfile), &rights) < 0 &&
errno != ENOSYS) {
error("can't limit pidfile descriptor: %m");
}
}

/* 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;
}

if (cap_rights_limit(STDIN_FILENO, &rights) < 0 && errno != ENOSYS)
error("can't limit stdin: %m");
cap_rights_init(&rights, CAP_WRITE);
if (cap_rights_limit(STDOUT_FILENO, &rights) < 0 && errno != ENOSYS)
error("can't limit stdout: %m");
if (cap_rights_limit(STDERR_FILENO, &rights) < 0 && errno != ENOSYS)
error("can't limit stderr: %m");
}

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:
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_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(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);

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);
}
}
    (1-1/1)