669 lines
16 KiB
C
669 lines
16 KiB
C
/*
|
||
* bootpgw.c - BOOTP GateWay
|
||
* This program forwards BOOTP Request packets to a BOOTP server.
|
||
*/
|
||
|
||
/************************************************************************
|
||
Copyright 1988, 1991 by Carnegie Mellon University
|
||
|
||
All Rights Reserved
|
||
|
||
Permission to use, copy, modify, and distribute this software and its
|
||
documentation for any purpose and without fee is hereby granted, provided
|
||
that the above copyright notice appear in all copies and that both that
|
||
copyright notice and this permission notice appear in supporting
|
||
documentation, and that the name of Carnegie Mellon University not be used
|
||
in advertising or publicity pertaining to distribution of the software
|
||
without specific, written prior permission.
|
||
|
||
CARNEGIE MELLON UNIVERSITY DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS
|
||
SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS.
|
||
IN NO EVENT SHALL CMU BE LIABLE FOR ANY SPECIAL, INDIRECT OR CONSEQUENTIAL
|
||
DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR
|
||
PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS
|
||
ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
|
||
SOFTWARE.
|
||
************************************************************************/
|
||
|
||
#include <sys/cdefs.h>
|
||
#ifndef lint
|
||
__RCSID("$NetBSD: bootpgw.c,v 1.12 2006/05/09 20:18:09 mrg Exp $");
|
||
#endif
|
||
|
||
/*
|
||
* BOOTPGW is typically used to forward BOOTP client requests from
|
||
* one subnet to a BOOTP server on a different subnet.
|
||
*/
|
||
|
||
#include <sys/types.h>
|
||
#include <sys/param.h>
|
||
#include <sys/socket.h>
|
||
#include <sys/ioctl.h>
|
||
#include <sys/file.h>
|
||
#include <sys/time.h>
|
||
#include <sys/stat.h>
|
||
#include <sys/poll.h>
|
||
|
||
#include <net/if.h>
|
||
#include <netinet/in.h>
|
||
#include <arpa/inet.h> /* inet_ntoa */
|
||
|
||
#ifndef NO_UNISTD
|
||
#include <unistd.h>
|
||
#endif
|
||
#include <stdlib.h>
|
||
#include <signal.h>
|
||
#include <stdio.h>
|
||
#include <string.h>
|
||
#include <errno.h>
|
||
#include <ctype.h>
|
||
#include <netdb.h>
|
||
#include <syslog.h>
|
||
#include <assert.h>
|
||
|
||
#ifdef NO_SETSID
|
||
# include <fcntl.h> /* for O_RDONLY, etc */
|
||
#endif
|
||
|
||
#ifndef USE_BFUNCS
|
||
# include <memory.h>
|
||
/* Yes, memcpy is OK here (no overlapped copies). */
|
||
# define bcopy(a,b,c) memcpy(b,a,c)
|
||
# define bzero(p,l) memset(p,0,l)
|
||
# define bcmp(a,b,c) memcmp(a,b,c)
|
||
#endif
|
||
|
||
#include "bootp.h"
|
||
#include "getif.h"
|
||
#include "hwaddr.h"
|
||
#include "report.h"
|
||
#include "patchlevel.h"
|
||
|
||
/* Local definitions: */
|
||
#define MAX_MSG_SIZE (3*512) /* Maximum packet size */
|
||
#define TRUE 1
|
||
#define FALSE 0
|
||
#define get_network_errmsg get_errmsg
|
||
|
||
|
||
|
||
/*
|
||
* Externals, forward declarations, and global variables
|
||
*/
|
||
|
||
static void usage(void);
|
||
static void handle_reply(void);
|
||
static void handle_request(void);
|
||
int main(int, char **);
|
||
|
||
/*
|
||
* IP port numbers for client and server obtained from /etc/services
|
||
*/
|
||
|
||
u_short bootps_port, bootpc_port;
|
||
|
||
|
||
/*
|
||
* Internet socket and interface config structures
|
||
*/
|
||
|
||
struct sockaddr_in bind_addr; /* Listening */
|
||
struct sockaddr_in clnt_addr; /* client address */
|
||
struct sockaddr_in serv_addr; /* server address */
|
||
|
||
|
||
/*
|
||
* option defaults
|
||
*/
|
||
int debug = 0; /* Debugging flag (level) */
|
||
int actualtimeout = 15 * 60000; /* fifteen minutes */
|
||
u_int maxhops = 4; /* Number of hops allowed for requests. */
|
||
u_int minwait = 3; /* Number of seconds client must wait before
|
||
its bootrequest packets are forwarded. */
|
||
|
||
/*
|
||
* General
|
||
*/
|
||
|
||
int s; /* Socket file descriptor */
|
||
char *pktbuf; /* Receive packet buffer */
|
||
int pktlen;
|
||
char *progname;
|
||
char *servername;
|
||
|
||
char myhostname[MAXHOSTNAMELEN + 1];
|
||
struct in_addr my_ip_addr;
|
||
|
||
|
||
|
||
|
||
/*
|
||
* Initialization such as command-line processing is done and then the
|
||
* main server loop is started.
|
||
*/
|
||
|
||
int
|
||
main(int argc, char **argv)
|
||
{
|
||
int timeout;
|
||
struct bootp *bp;
|
||
struct servent *servp;
|
||
struct hostent *hep;
|
||
char *stmp;
|
||
socklen_t ba_len, ra_len;
|
||
int n;
|
||
int nfound;
|
||
struct pollfd set[1];
|
||
int standalone;
|
||
|
||
progname = strrchr(argv[0], '/');
|
||
if (progname) progname++;
|
||
else progname = argv[0];
|
||
|
||
/*
|
||
* Initialize logging.
|
||
*/
|
||
report_init(0); /* uses progname */
|
||
|
||
/*
|
||
* Log startup
|
||
*/
|
||
report(LOG_INFO, "version %s.%d", VERSION, PATCHLEVEL);
|
||
|
||
/* Debugging for compilers with struct padding. */
|
||
assert(sizeof(struct bootp) == BP_MINPKTSZ);
|
||
|
||
/* Get space for receiving packets and composing replies. */
|
||
pktbuf = malloc(MAX_MSG_SIZE);
|
||
if (!pktbuf) {
|
||
report(LOG_ERR, "malloc failed");
|
||
exit(1);
|
||
}
|
||
bp = (struct bootp *) pktbuf;
|
||
|
||
/*
|
||
* Check to see if a socket was passed to us from inetd.
|
||
*
|
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* Use getsockname() to determine if descriptor 0 is indeed a socket
|
||
* (and thus we are probably a child of inetd) or if it is instead
|
||
* something else and we are running standalone.
|
||
*/
|
||
s = 0;
|
||
ba_len = sizeof(bind_addr);
|
||
bzero((char *) &bind_addr, ba_len);
|
||
errno = 0;
|
||
standalone = TRUE;
|
||
if (getsockname(s, (struct sockaddr *) &bind_addr, &ba_len) == 0) {
|
||
/*
|
||
* Descriptor 0 is a socket. Assume we are a child of inetd.
|
||
*/
|
||
if (bind_addr.sin_family == AF_INET) {
|
||
standalone = FALSE;
|
||
bootps_port = ntohs(bind_addr.sin_port);
|
||
} else {
|
||
/* Some other type of socket? */
|
||
report(LOG_INFO, "getsockname: not an INET socket");
|
||
}
|
||
}
|
||
/*
|
||
* Set defaults that might be changed by option switches.
|
||
*/
|
||
stmp = NULL;
|
||
timeout = actualtimeout;
|
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gethostname(myhostname, sizeof(myhostname));
|
||
myhostname[sizeof(myhostname) - 1] = '\0';
|
||
hep = gethostbyname(myhostname);
|
||
if (!hep) {
|
||
printf("Can not get my IP address\n");
|
||
exit(1);
|
||
}
|
||
bcopy(hep->h_addr, (char *)&my_ip_addr, sizeof(my_ip_addr));
|
||
|
||
/*
|
||
* Read switches.
|
||
*/
|
||
for (argc--, argv++; argc > 0; argc--, argv++) {
|
||
if (argv[0][0] != '-')
|
||
break;
|
||
switch (argv[0][1]) {
|
||
|
||
case 'd': /* debug level */
|
||
if (argv[0][2]) {
|
||
stmp = &(argv[0][2]);
|
||
} else if (argv[1] && argv[1][0] == '-') {
|
||
/*
|
||
* Backwards-compatible behavior:
|
||
* no parameter, so just increment the debug flag.
|
||
*/
|
||
debug++;
|
||
break;
|
||
} else {
|
||
argc--;
|
||
argv++;
|
||
stmp = argv[0];
|
||
}
|
||
if (!stmp || (sscanf(stmp, "%d", &n) != 1) || (n < 0)) {
|
||
fprintf(stderr,
|
||
"%s: invalid debug level\n", progname);
|
||
break;
|
||
}
|
||
debug = n;
|
||
break;
|
||
|
||
case 'h': /* hop count limit */
|
||
if (argv[0][2]) {
|
||
stmp = &(argv[0][2]);
|
||
} else {
|
||
argc--;
|
||
argv++;
|
||
stmp = argv[0];
|
||
}
|
||
if (!stmp || (sscanf(stmp, "%d", &n) != 1) ||
|
||
(n < 0) || (n > 16))
|
||
{
|
||
fprintf(stderr,
|
||
"bootpgw: invalid hop count limit\n");
|
||
break;
|
||
}
|
||
maxhops = (u_int)n;
|
||
break;
|
||
|
||
case 'i': /* inetd mode */
|
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standalone = FALSE;
|
||
break;
|
||
|
||
case 's': /* standalone mode */
|
||
standalone = TRUE;
|
||
break;
|
||
|
||
case 't': /* timeout */
|
||
if (argv[0][2]) {
|
||
stmp = &(argv[0][2]);
|
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} else {
|
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argc--;
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argv++;
|
||
stmp = argv[0];
|
||
}
|
||
if (!stmp || (sscanf(stmp, "%d", &n) != 1) || (n < 0)) {
|
||
fprintf(stderr,
|
||
"%s: invalid timeout specification\n", progname);
|
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break;
|
||
}
|
||
actualtimeout = n * 60000;
|
||
/*
|
||
* If the actual timeout is zero, pass INFTIM
|
||
* to poll so it blocks indefinitely, otherwise,
|
||
* use the actual timeout value.
|
||
*/
|
||
timeout = (n > 0) ? actualtimeout : INFTIM;
|
||
break;
|
||
|
||
case 'w': /* wait time */
|
||
if (argv[0][2]) {
|
||
stmp = &(argv[0][2]);
|
||
} else {
|
||
argc--;
|
||
argv++;
|
||
stmp = argv[0];
|
||
}
|
||
if (!stmp || (sscanf(stmp, "%d", &n) != 1) ||
|
||
(n < 0) || (n > 60))
|
||
{
|
||
fprintf(stderr,
|
||
"bootpgw: invalid wait time\n");
|
||
break;
|
||
}
|
||
minwait = (u_int)n;
|
||
break;
|
||
|
||
default:
|
||
fprintf(stderr, "%s: unknown switch: -%c\n",
|
||
progname, argv[0][1]);
|
||
usage();
|
||
break;
|
||
|
||
} /* switch */
|
||
} /* for args */
|
||
|
||
/* Make sure server name argument is suplied. */
|
||
servername = argv[0];
|
||
if (!servername) {
|
||
fprintf(stderr, "bootpgw: missing server name\n");
|
||
usage();
|
||
}
|
||
/*
|
||
* Get address of real bootp server.
|
||
*/
|
||
if (inet_aton(servername, &serv_addr.sin_addr) == 0) {
|
||
hep = gethostbyname(servername);
|
||
if (!hep) {
|
||
fprintf(stderr, "bootpgw: can't get addr for %s\n", servername);
|
||
exit(1);
|
||
}
|
||
memcpy(&serv_addr.sin_addr, hep->h_addr,
|
||
sizeof(serv_addr.sin_addr));
|
||
}
|
||
|
||
if (standalone) {
|
||
/*
|
||
* Go into background and disassociate from controlling terminal.
|
||
* XXX - This is not the POSIX way (Should use setsid). -gwr
|
||
*/
|
||
if (debug < 3) {
|
||
if (fork())
|
||
exit(0);
|
||
#ifdef NO_SETSID
|
||
setpgrp(0,0);
|
||
#ifdef TIOCNOTTY
|
||
n = open("/dev/tty", O_RDWR);
|
||
if (n >= 0) {
|
||
ioctl(n, TIOCNOTTY, (char *) 0);
|
||
(void) close(n);
|
||
}
|
||
#endif /* TIOCNOTTY */
|
||
#else /* SETSID */
|
||
if (setsid() < 0)
|
||
perror("setsid");
|
||
#endif /* SETSID */
|
||
} /* if debug < 3 */
|
||
/*
|
||
* Nuke any timeout value
|
||
*/
|
||
timeout = INFTIM;
|
||
|
||
/*
|
||
* Here, bootpd would do:
|
||
* chdir
|
||
* tzone_init
|
||
* rdtab_init
|
||
* readtab
|
||
*/
|
||
|
||
/*
|
||
* Create a socket.
|
||
*/
|
||
if ((s = socket(AF_INET, SOCK_DGRAM, 0)) < 0) {
|
||
report(LOG_ERR, "socket: %s", get_network_errmsg());
|
||
exit(1);
|
||
}
|
||
/*
|
||
* Get server's listening port number
|
||
*/
|
||
servp = getservbyname("bootps", "udp");
|
||
if (servp) {
|
||
bootps_port = ntohs((u_short) servp->s_port);
|
||
} else {
|
||
bootps_port = (u_short) IPPORT_BOOTPS;
|
||
report(LOG_ERR,
|
||
"udp/bootps: unknown service -- assuming port %d",
|
||
bootps_port);
|
||
}
|
||
|
||
/*
|
||
* Bind socket to BOOTPS port.
|
||
*/
|
||
bind_addr.sin_family = AF_INET;
|
||
bind_addr.sin_port = htons(bootps_port);
|
||
bind_addr.sin_addr.s_addr = INADDR_ANY;
|
||
if (bind(s, (struct sockaddr *) &bind_addr,
|
||
sizeof(bind_addr)) < 0)
|
||
{
|
||
report(LOG_ERR, "bind: %s", get_network_errmsg());
|
||
exit(1);
|
||
}
|
||
} /* if standalone */
|
||
/*
|
||
* Get destination port number so we can reply to client
|
||
*/
|
||
servp = getservbyname("bootpc", "udp");
|
||
if (servp) {
|
||
bootpc_port = ntohs(servp->s_port);
|
||
} else {
|
||
report(LOG_ERR,
|
||
"udp/bootpc: unknown service -- assuming port %d",
|
||
IPPORT_BOOTPC);
|
||
bootpc_port = (u_short) IPPORT_BOOTPC;
|
||
}
|
||
|
||
/* no signal catchers */
|
||
|
||
/*
|
||
* Process incoming requests.
|
||
*/
|
||
set[0].fd = s;
|
||
set[0].events = POLLIN;
|
||
for (;;) {
|
||
nfound = poll(set, 1, timeout);
|
||
if (nfound < 0) {
|
||
if (errno != EINTR) {
|
||
report(LOG_ERR, "poll: %s", get_errmsg());
|
||
}
|
||
continue;
|
||
}
|
||
if (nfound == 0) {
|
||
report(LOG_INFO, "exiting after %d minute%s of inactivity",
|
||
actualtimeout / 60000,
|
||
actualtimeout == 60000 ? "" : "s");
|
||
exit(0);
|
||
}
|
||
ra_len = sizeof(clnt_addr);
|
||
n = recvfrom(s, pktbuf, MAX_MSG_SIZE, 0,
|
||
(struct sockaddr *) &clnt_addr, &ra_len);
|
||
if (n <= 0) {
|
||
continue;
|
||
}
|
||
if (debug > 3) {
|
||
report(LOG_INFO, "recvd pkt from IP addr %s",
|
||
inet_ntoa(clnt_addr.sin_addr));
|
||
}
|
||
if (n < sizeof(struct bootp)) {
|
||
if (debug) {
|
||
report(LOG_INFO, "received short packet");
|
||
}
|
||
continue;
|
||
}
|
||
pktlen = n;
|
||
|
||
switch (bp->bp_op) {
|
||
case BOOTREQUEST:
|
||
handle_request();
|
||
break;
|
||
case BOOTREPLY:
|
||
handle_reply();
|
||
break;
|
||
}
|
||
}
|
||
}
|
||
|
||
|
||
|
||
|
||
/*
|
||
* Print "usage" message and exit
|
||
*/
|
||
|
||
static void
|
||
usage(void)
|
||
{
|
||
fprintf(stderr,
|
||
"usage: bootpgw [-d level] [-i] [-s] [-t timeout] server\n");
|
||
fprintf(stderr, "\t -d n\tset debug level\n");
|
||
fprintf(stderr, "\t -h n\tset max hop count\n");
|
||
fprintf(stderr, "\t -i\tforce inetd mode (run as child of inetd)\n");
|
||
fprintf(stderr, "\t -s\tforce standalone mode (run without inetd)\n");
|
||
fprintf(stderr, "\t -t n\tset inetd exit timeout to n minutes\n");
|
||
fprintf(stderr, "\t -w n\tset min wait time (secs)\n");
|
||
exit(1);
|
||
}
|
||
|
||
|
||
|
||
/*
|
||
* Process BOOTREQUEST packet.
|
||
*
|
||
* Note, this just forwards the request to a real server.
|
||
*/
|
||
static void
|
||
handle_request(void)
|
||
{
|
||
struct bootp *bp = (struct bootp *) pktbuf;
|
||
#if 0
|
||
struct ifreq *ifr;
|
||
#endif
|
||
u_short secs, hops;
|
||
|
||
/* XXX - SLIP init: Set bp_ciaddr = clnt_addr here? */
|
||
|
||
if (debug) {
|
||
report(LOG_INFO, "request from %s",
|
||
inet_ntoa(clnt_addr.sin_addr));
|
||
}
|
||
/* Has the client been waiting long enough? */
|
||
secs = ntohs(bp->bp_secs);
|
||
if (secs < minwait)
|
||
return;
|
||
|
||
/* Has this packet hopped too many times? */
|
||
hops = ntohs(bp->bp_hops);
|
||
if (++hops > maxhops) {
|
||
report(LOG_NOTICE, "request from %s reached hop limit",
|
||
inet_ntoa(clnt_addr.sin_addr));
|
||
return;
|
||
}
|
||
bp->bp_hops = htons(hops);
|
||
|
||
/*
|
||
* Here one might discard a request from the same subnet as the
|
||
* real server, but we can assume that the real server will send
|
||
* a reply to the client before it waits for minwait seconds.
|
||
*/
|
||
|
||
/* If gateway address is not set, put in local interface addr. */
|
||
if (bp->bp_giaddr.s_addr == 0) {
|
||
#if 0 /* BUG */
|
||
struct sockaddr_in *sip;
|
||
/*
|
||
* XXX - This picks the wrong interface when the receive addr
|
||
* is the broadcast address. There is no portable way to
|
||
* find out which interface a broadcast was received on. -gwr
|
||
* (Thanks to <walker@zk3.dec.com> for finding this bug!)
|
||
*/
|
||
ifr = getif(s, &clnt_addr.sin_addr);
|
||
if (!ifr) {
|
||
report(LOG_NOTICE, "no interface for request from %s",
|
||
inet_ntoa(clnt_addr.sin_addr));
|
||
return;
|
||
}
|
||
sip = (struct sockaddr_in *) &(ifr->ifr_addr);
|
||
bp->bp_giaddr = sip->sin_addr;
|
||
#else /* BUG */
|
||
/*
|
||
* XXX - Just set "giaddr" to our "official" IP address.
|
||
* RFC 1532 says giaddr MUST be set to the address of the
|
||
* interface on which the request was received. Setting
|
||
* it to our "default" IP address is not strictly correct,
|
||
* but is good enough to allow the real BOOTP server to
|
||
* get the reply back here. Then, before we forward the
|
||
* reply to the client, the giaddr field is corrected.
|
||
* (In case the client uses giaddr, which it should not.)
|
||
* See handle_reply()
|
||
*/
|
||
bp->bp_giaddr = my_ip_addr;
|
||
#endif /* BUG */
|
||
|
||
/*
|
||
* XXX - DHCP says to insert a subnet mask option into the
|
||
* options area of the request (if vendor magic == std).
|
||
*/
|
||
}
|
||
/* Set up socket address for send. */
|
||
serv_addr.sin_family = AF_INET;
|
||
serv_addr.sin_port = htons(bootps_port);
|
||
|
||
/* Send reply with same size packet as request used. */
|
||
if (sendto(s, pktbuf, pktlen, 0,
|
||
(struct sockaddr *) &serv_addr,
|
||
sizeof(serv_addr)) < 0)
|
||
{
|
||
report(LOG_ERR, "sendto: %s", get_network_errmsg());
|
||
}
|
||
}
|
||
|
||
|
||
|
||
/*
|
||
* Process BOOTREPLY packet.
|
||
*/
|
||
static void
|
||
handle_reply(void)
|
||
{
|
||
struct bootp *bp = (struct bootp *) pktbuf;
|
||
struct ifreq *ifr;
|
||
struct sockaddr_in *sip;
|
||
u_char canon_haddr[MAXHADDRLEN];
|
||
unsigned char *ha;
|
||
int len;
|
||
|
||
if (debug) {
|
||
report(LOG_INFO, " reply for %s",
|
||
inet_ntoa(bp->bp_yiaddr));
|
||
}
|
||
/* Make sure client is directly accessible. */
|
||
ifr = getif(s, &(bp->bp_yiaddr));
|
||
if (!ifr) {
|
||
report(LOG_NOTICE, "no interface for reply to %s",
|
||
inet_ntoa(bp->bp_yiaddr));
|
||
return;
|
||
}
|
||
#if 1 /* Experimental (see BUG above) */
|
||
/* #ifdef CATER_TO_OLD_CLIENTS ? */
|
||
/*
|
||
* The giaddr field has been set to our "default" IP address
|
||
* which might not be on the same interface as the client.
|
||
* In case the client looks at giaddr, (which it should not)
|
||
* giaddr is now set to the address of the correct interface.
|
||
*/
|
||
sip = (struct sockaddr_in *) &(ifr->ifr_addr);
|
||
bp->bp_giaddr = sip->sin_addr;
|
||
#endif
|
||
|
||
/* Set up socket address for send to client. */
|
||
clnt_addr.sin_family = AF_INET;
|
||
clnt_addr.sin_addr = bp->bp_yiaddr;
|
||
clnt_addr.sin_port = htons(bootpc_port);
|
||
|
||
/* Create an ARP cache entry for the client. */
|
||
ha = bp->bp_chaddr;
|
||
len = bp->bp_hlen;
|
||
if (len > MAXHADDRLEN)
|
||
len = MAXHADDRLEN;
|
||
if (bp->bp_htype == HTYPE_IEEE802) {
|
||
haddr_conv802(ha, canon_haddr, len);
|
||
ha = canon_haddr;
|
||
}
|
||
if (debug > 1)
|
||
report(LOG_INFO, "setarp %s - %s",
|
||
inet_ntoa(bp->bp_yiaddr), haddrtoa(ha, len));
|
||
setarp(s, &bp->bp_yiaddr, ha, len);
|
||
|
||
/* Send reply with same size packet as request used. */
|
||
if (sendto(s, pktbuf, pktlen, 0,
|
||
(struct sockaddr *) &clnt_addr,
|
||
sizeof(clnt_addr)) < 0)
|
||
{
|
||
report(LOG_ERR, "sendto: %s", get_network_errmsg());
|
||
}
|
||
}
|
||
|
||
/*
|
||
* Local Variables:
|
||
* tab-width: 4
|
||
* c-indent-level: 4
|
||
* c-argdecl-indent: 4
|
||
* c-continued-statement-offset: 4
|
||
* c-continued-brace-offset: -4
|
||
* c-label-offset: -4
|
||
* c-brace-offset: 0
|
||
* End:
|
||
*/
|