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freebsd-dev/sbin/dhclient/dhclient.c
Conrad Meyer fb0eab090e dhclient: Fix the trivial buffer overruns correctly 
A DHCP client identifier is simply the hardware type (one byte) concatenated
with the hardware address (some variable number of bytes, but at most 16).
Limit the size of the temporary buffer to match and the rest of the
calculations shake out correctly.

This is a follow-up to the incorrect r299512, reverted in r300172.

CIDs:		1008682, 1305550
Sponsored by:	EMC / Isilon Storage Division
2016-05-18 23:41:55 +00:00

2762 lines
75 KiB
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/* $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 "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, 0644, &otherpid);
if (pidfile == NULL) {
if (errno == EEXIST)
error("dhclient already running, pid: %d.", otherpid);
if (errno == EAGAIN)
error("dhclient already running.");
warning("Cannot open or create pidfile: %m");
}
if ((ifi = calloc(1, sizeof(struct interface_info))) == NULL)
error("calloc");
if (strlcpy(ifi->name, argv[0], IFNAMSIZ) >= IFNAMSIZ)
error("Interface name too long");
if (path_dhclient_db == NULL && asprintf(&path_dhclient_db, "%s.%s",
_PATH_DHCLIENT_DB, ifi->name) == -1)
error("asprintf");
if (quiet)
log_perror = 0;
tzset();
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;
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);
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(ip->hw_address.haddr) + 1];
if (!options[DHO_DHCP_CLIENT_IDENTIFIER]) {
int hwlen = (ip->hw_address.hlen < sizeof(client_ident)-1) ?
ip->hw_address.hlen : sizeof(client_ident)-1;
client_ident[0] = ip->hw_address.htype;
memcpy(&client_ident[1], ip->hw_address.haddr, hwlen);
options[DHO_DHCP_CLIENT_IDENTIFIER] = &option_elements[DHO_DHCP_CLIENT_IDENTIFIER];
options[DHO_DHCP_CLIENT_IDENTIFIER]->value = client_ident;
options[DHO_DHCP_CLIENT_IDENTIFIER]->len = hwlen+1;
options[DHO_DHCP_CLIENT_IDENTIFIER]->buf_size = hwlen+1;
options[DHO_DHCP_CLIENT_IDENTIFIER]->timeout = 0xFFFFFFFF;
}
/* Set up the option buffer... */
ip->client->packet_length = cons_options(NULL, &ip->client->packet, 0,
options, 0, 0, 0, NULL, 0);
if (ip->client->packet_length < BOOTP_MIN_LEN)
ip->client->packet_length = BOOTP_MIN_LEN;
ip->client->packet.op = BOOTREQUEST;
ip->client->packet.htype = ip->hw_address.htype;
ip->client->packet.hlen = ip->hw_address.hlen;
ip->client->packet.hops = 0;
ip->client->packet.xid = arc4random();
ip->client->packet.secs = 0; /* filled in by send_discover. */
ip->client->packet.flags = 0;
memset(&(ip->client->packet.ciaddr),
0, sizeof(ip->client->packet.ciaddr));
memset(&(ip->client->packet.yiaddr),
0, sizeof(ip->client->packet.yiaddr));
memset(&(ip->client->packet.siaddr),
0, sizeof(ip->client->packet.siaddr));
memset(&(ip->client->packet.giaddr),
0, sizeof(ip->client->packet.giaddr));
memcpy(ip->client->packet.chaddr,
ip->hw_address.haddr, ip->hw_address.hlen);
}
void
make_request(struct interface_info *ip, struct client_lease * lease)
{
unsigned char request = DHCPREQUEST;
struct tree_cache *options[256];
struct tree_cache option_elements[256];
int i;
memset(options, 0, sizeof(options));
memset(&ip->client->packet, 0, sizeof(ip->client->packet));
/* Set DHCP_MESSAGE_TYPE to DHCPREQUEST */
i = DHO_DHCP_MESSAGE_TYPE;
options[i] = &option_elements[i];
options[i]->value = &request;
options[i]->len = sizeof(request);
options[i]->buf_size = sizeof(request);
options[i]->timeout = 0xFFFFFFFF;
/* Request the options we want */
i = DHO_DHCP_PARAMETER_REQUEST_LIST;
options[i] = &option_elements[i];
options[i]->value = ip->client->config->requested_options;
options[i]->len = ip->client->config->requested_option_count;
options[i]->buf_size =
ip->client->config->requested_option_count;
options[i]->timeout = 0xFFFFFFFF;
/* If we are requesting an address that hasn't yet been assigned
to us, use the DHCP Requested Address option. */
if (ip->client->state == S_REQUESTING) {
/* Send back the server identifier... */
i = DHO_DHCP_SERVER_IDENTIFIER;
options[i] = &option_elements[i];
options[i]->value = lease->options[i].data;
options[i]->len = lease->options[i].len;
options[i]->buf_size = lease->options[i].len;
options[i]->timeout = 0xFFFFFFFF;
}
if (ip->client->state == S_REQUESTING ||
ip->client->state == S_REBOOTING) {
ip->client->requested_address = lease->address;
i = DHO_DHCP_REQUESTED_ADDRESS;
options[i] = &option_elements[i];
options[i]->value = lease->address.iabuf;
options[i]->len = lease->address.len;
options[i]->buf_size = lease->address.len;
options[i]->timeout = 0xFFFFFFFF;
} else
ip->client->requested_address.len = 0;
/* Send any options requested in the config file. */
for (i = 0; i < 256; i++)
if (!options[i] &&
ip->client->config->send_options[i].data) {
options[i] = &option_elements[i];
options[i]->value =
ip->client->config->send_options[i].data;
options[i]->len =
ip->client->config->send_options[i].len;
options[i]->buf_size =
ip->client->config->send_options[i].len;
options[i]->timeout = 0xFFFFFFFF;
}
/* send host name if not set via config file. */
if (!options[DHO_HOST_NAME]) {
if (hostname[0] != '\0') {
size_t len;
char* posDot = strchr(hostname, '.');
if (posDot != NULL)
len = posDot - hostname;
else
len = strlen(hostname);
options[DHO_HOST_NAME] = &option_elements[DHO_HOST_NAME];
options[DHO_HOST_NAME]->value = hostname;
options[DHO_HOST_NAME]->len = len;
options[DHO_HOST_NAME]->buf_size = len;
options[DHO_HOST_NAME]->timeout = 0xFFFFFFFF;
}
}
/* set unique client identifier */
char client_ident[sizeof(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);
}
}
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