dhcp6_ctlclient.c

/*	$KAME: dhcp6_ctlclient.c,v 1.5 2005/01/12 06:06:11 suz Exp $	*/

/*
 * Copyright (C) 2004 WIDE Project.
 * 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 project 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 PROJECT 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 PROJECT 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.
 */
#include <sys/types.h>
#include <sys/socket.h>
#include <sys/time.h>
#include <time.h>

#include <netinet/in.h>

#include <unistd.h>
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <netdb.h>
#include <err.h>

#include <control.h>
#include <auth.h>
#include <base64.h>

#define MD5_DIGESTLENGTH 16
#define DEFAULT_SERVER_KEYFILE SYSCONFDIR "/dhcp6sctlkey"
#define DEFAULT_CLIENT_KEYFILE SYSCONFDIR "/dhcp6cctlkey"

static const char *ctladdr;
static const char *ctlport;

static enum { CTLCLIENT, CTLSERVER } ctltype = CTLCLIENT;

static inline int put16(char **, int *, u_int16_t);
static inline int put32(char **, int *, u_int32_t);
static inline int putval(char **, int *, void *, size_t);

static int setup_auth(const char *, struct keyinfo *, int *);
static int make_command(int, char **, char **, size_t *,
    struct keyinfo *, int);
static int make_remove_command(int, char **, char **, int *);
static int make_start_command(int, char **, char **, int *);
static int make_stop_command(int, char **, char **, int *);
static int make_binding_object(int, char **, char **, int *);
static int make_interface_object(int, char **, char **, int *);
static int make_ia_object(int, char **, char **, int *);
static int parse_duid(char *, int *, char **, int *);
static void usage(void) __attribute__((__noreturn__));

int
main(int argc, char *argv[])
{
	int cc, ch, s, error, passed;
	int Cflag = 0, Sflag = 0;
	char *cbuf = NULL;
	size_t clen = 0;
	struct addrinfo hints, *res0, *res;
	int digestlen;
	const char *keyfile = NULL;
	struct keyinfo key;

	while ((ch = getopt(argc, argv, "CSa:k:p:")) != -1) {
		switch (ch) {
		case 'C':
			if (Sflag)
				errx(1, "-C and -S are exclusive");
			Cflag = 1;
			ctltype = CTLCLIENT;
			break;
		case 'S':
			if (Cflag)
				errx(1, "-C and -S are exclusive");
			Sflag = 1;
			ctltype = CTLSERVER;
			break;
		case 'a':
			ctladdr = optarg;
			break;
		case 'k':
			keyfile = optarg;
			break;
		case 'p':
			ctlport = optarg;
			break;
		default:
			usage();
		}
	}
	argc -= optind;
	argv += optind;

	if (argc == 0)
		usage();

	switch (ctltype) {
	case CTLCLIENT:
		if (ctladdr == NULL)
			ctladdr = DEFAULT_CLIENT_CONTROL_ADDR;
		if (ctlport == NULL)
			ctlport = DEFAULT_CLIENT_CONTROL_PORT;
		if (keyfile == NULL)
			keyfile = DEFAULT_CLIENT_KEYFILE;
		break;
	case CTLSERVER:
		if (ctladdr == NULL)
			ctladdr = DEFAULT_SERVER_CONTROL_ADDR;
		if (ctlport == NULL)
			ctlport = DEFAULT_SERVER_CONTROL_PORT;
		if (keyfile == NULL)
			keyfile = DEFAULT_SERVER_KEYFILE;
		break;
	}

	memset(&key, 0, sizeof(key));
	digestlen = 0;
	if (setup_auth(keyfile, &key, &digestlen) != 0)
		errx(1, "failed to setup message authentication");

	if ((passed = make_command(argc, argv, &cbuf, &clen,
	    &key, digestlen)) < 0) {
		errx(1, "failed to make command buffer");
	}
	argc -= passed;
	argv += passed;
	if (argc != 0)
		warnx("redundant command argument after \"%s\"", argv[0]);

	memset(&hints, 0, sizeof(hints));
	hints.ai_family = AF_INET6;
	hints.ai_socktype = SOCK_STREAM;
	hints.ai_protocol = IPPROTO_TCP;
	error = getaddrinfo(ctladdr, ctlport, &hints, &res0);
	if (error != 0)
		errx(1, "getaddrinfo failed: %s", gai_strerror(error));

	s = -1;
	for (res = res0; res != NULL; res = res->ai_next) {
		s = socket(res->ai_family, res->ai_socktype,
		    res->ai_protocol);
		if (s < 0) {
			warn("socket");
			continue;
		}
		if (connect(s, res->ai_addr, res->ai_addrlen) < 0) {
			warn("connect");
			s = -1;
			continue;
		}
		break;
	}
	freeaddrinfo(res0);
	if (s < 0) {
		warnx("failed to connect to the %s",
		    ctltype == CTLCLIENT ? "client" : "server");
		exit(1);
	}

	cc = write(s, cbuf, clen);
	if (cc < 0)
		err(1, "write command");
	if (cc != clen)
		errx(1, "failed to send complete command");

	close(s);
	free(cbuf);

	exit(0);
}

static int
setup_auth(const char *keyfile, struct keyinfo *key, int *digestlenp)
{
	FILE *fp = NULL;
	char line[1024], secret[1024];
	int secretlen;

	key->secret = NULL;

	/* Currently, we only support HMAC-MD5 for authentication. */
	*digestlenp = MD5_DIGESTLENGTH;

	if ((fp = fopen(keyfile, "r")) == NULL) {
		warn("fopen: %s", keyfile);
		return (-1);
	}
	if (fgets(line, sizeof(line), fp) == NULL && ferror(fp)) {
		warn("fgets failed");
		goto fail;
	}
	if ((secretlen = base64_decodestring(line, secret, sizeof(secret)))
	    < 0) {
		warnx("failed to decode base64 string");
		goto fail;
	}
	if ((key->secret = malloc(secretlen)) == NULL) {
		warn("setup_auth: malloc failed");
		goto fail;
	}
	key->secretlen = (size_t)secretlen;
	memcpy(key->secret, secret, secretlen);

	fclose(fp);

	return (0);

  fail:
	if (fp != NULL)
		fclose(fp);
	if (key->secret != NULL)
		free(key->secret);
	return (-1);
}

static inline int
put16(char **bpp, int *lenp, u_int16_t val)
{
	char *bp = *bpp;
	int len = *lenp;

	if (len < sizeof(val))
		return (-1);

	val = htons(val);
	memcpy(bp, &val, sizeof(val));
	bp += sizeof(val);
	len -= sizeof(val);

	*bpp = bp;
	*lenp = len;

	return (0);
}

static inline int
put32(char **bpp, int *lenp, u_int32_t val)
{
	char *bp = *bpp;
	int len = *lenp;

	if (len < sizeof(val))
		return (-1);

	val = htonl(val);
	memcpy(bp, &val, sizeof(val));
	bp += sizeof(val);
	len -= sizeof(val);

	*bpp = bp;
	*lenp = len;

	return (0);
}

static inline int
putval(char **bpp, int *lenp, void *val, size_t valsize)
{
	char *bp = *bpp;
	int len = *lenp;

	if (len < valsize)
		return (-1);

	memcpy(bp, val, valsize);
	bp += valsize;
	len -= valsize;

	*bpp = bp;
	*lenp = len;

	return (0);
}

static int
make_command(int argc, char **argv, char **bufp, size_t *lenp,
    struct keyinfo *key, int authlen)
{
	struct dhcp6ctl ctl;
	char commandbuf[4096];	/* XXX: ad-hoc value */
	char *bp, *buf, *mac;
	int buflen, len;
	int argc_passed = 0, passed;
	time_t now;

	if (argc == 0) {
		warnx("command is too short");
		return (-1);
	}

	bp = commandbuf + sizeof(ctl) + authlen;
	if (bp >= commandbuf + sizeof(commandbuf)) {
		warnx("make_command: local buffer is too short");
		return (-1);
	}
	buflen = sizeof(commandbuf) - sizeof(ctl);

	memset(&ctl, 0, sizeof(ctl));
	ctl.version = htons(DHCP6CTL_VERSION);

	if (strcmp(argv[0], "reload") == 0)
		ctl.command = htons(DHCP6CTL_COMMAND_RELOAD);
	else if (strcmp(argv[0], "remove") == 0) {
		if (ctltype != CTLSERVER) {
			warnx("remove command is only for server");
			return (-1);
		}
		if ((passed = make_remove_command(argc - 1, argv + 1,
		    &bp, &buflen)) < 0) {
			return (-1);
		}
		argc_passed += passed;
		ctl.command = htons(DHCP6CTL_COMMAND_REMOVE);
	} else if (strcmp(argv[0], "start") == 0) {
		if ((passed = make_start_command(argc - 1, argv + 1,
		    &bp, &buflen)) < 0) {
			return (-1);
		}
		argc_passed += passed;
		ctl.command = htons(DHCP6CTL_COMMAND_START);
	} else if (strcmp(argv[0], "stop") == 0) {
		if ((passed = make_stop_command(argc - 1, argv + 1,
		    &bp, &buflen)) < 0) {
			return (-1);
		}
		argc_passed += passed;
		ctl.command = htons(DHCP6CTL_COMMAND_STOP);
	} else {
		warnx("unknown command: %s", argv[0]);
		return (-1);
	}

	len = bp - commandbuf;
	ctl.len = htons(len - sizeof(ctl));

	if ((now = time(NULL)) < 0) {
		warn("failed to get current time");
		return (-1);
	}
	ctl.timestamp = htonl((u_int32_t)now);

	memcpy(commandbuf, &ctl, sizeof(ctl));

	mac = commandbuf + sizeof(ctl);
	memset(mac, 0, authlen);
	if (dhcp6_calc_mac(commandbuf, len, DHCP6CTL_AUTHPROTO_UNDEF,
	    DHCP6CTL_AUTHALG_HMACMD5, sizeof(ctl), key) != 0) {
		warnx("failed to calculate MAC");
		return (-1);
	}

	if ((buf = malloc(len)) == NULL) {
		warn("memory allocation failed");
		return (-1);
	}
	memcpy(buf, commandbuf, len);

	*lenp = len;
	*bufp = buf;

	argc_passed++;

	return (argc_passed);
}

static int
make_remove_command(int argc, char **argv, char **bpp, int *lenp)
{
	int argc_passed = 0, passed;

	if (argc == 0) {
		warnx("make_remove_command: command is too short");
		return (-1);
	}

	if (strcmp(argv[0], "binding") == 0) {
		if (put32(bpp, lenp, DHCP6CTL_BINDING))
			goto fail;
		if ((passed = make_binding_object(argc - 1, argv + 1,
		    bpp, lenp)) < 0) {
			return (-1);
		}
		argc_passed += passed;
	} else {
		warnx("remove target not supported: %s", argv[0]);
		return (-1);
	}

	argc_passed++;
	return (argc_passed);

  fail:
	warnx("make_remove_command failed");
	return (-1);
}

static int
make_start_command(int argc, char **argv, char **bpp, int *lenp)
{
	int argc_passed = 0, passed;

	if (argc == 0) {
		warnx("make_remove_command: command is too short");
		return (-1);
	}

	if (ctltype != CTLCLIENT) {
		warnx("client-only command is specified for a server");
		return (-1);
	}

	if (strcmp(argv[0], "interface") == 0) {
		if (put32(bpp, lenp, DHCP6CTL_INTERFACE))
			goto fail;
		if ((passed = make_interface_object(argc - 1, argv + 1,
		    bpp, lenp)) < 0) {
			return (-1);
		}
		argc_passed += passed;
	} else {
		warnx("start target not supported: %s", argv[0]);
		return (-1);
	}

	argc_passed++;
	return (argc_passed);

  fail:
	warnx("make_start_command failed");
	return (-1);
}

static int
make_stop_command(int argc, char **argv, char **bpp, int *lenp)
{
	int argc_passed = 0, passed;

	if (argc == 0)
		return (0);

	if (ctltype != CTLCLIENT) {
		warnx("client-only command is specified for a server");
		return (-1);
	}

	if (strcmp(argv[0], "interface") == 0) {
		if (put32(bpp, lenp, DHCP6CTL_INTERFACE))
			goto fail;
		if ((passed = make_interface_object(argc - 1, argv + 1,
		    bpp, lenp)) < 0) {
			return (-1);
		}
		argc_passed += passed;
	} else {
		warnx("stop target not supported: %s", argv[0]);
		return (-1);
	}

	argc_passed++;
	return (argc_passed);

  fail:
	warnx("make_stop_command failed");
	return (-1);
}

static int
make_interface_object(int argc, char **argv, char **bpp, int *lenp)
{
	int iflen;
	int argc_passed = 0;

	if (argc == 0) {
		warnx("make_interface_object: interface not specified");
		return (-1);
	}
	argc_passed++;

	iflen = strlen(argv[0]) + 1;
	if (put32(bpp, lenp, (u_int32_t)iflen))
		goto fail;
	if (putval(bpp, lenp, argv[0], strlen(argv[0]) + 1))
		goto fail;

	return (argc_passed);

  fail:
	warnx("make_interface_object: failed");
	return (-1);
}	

static int
make_binding_object(int argc, char **argv, char **bpp, int *lenp)
{
	int argc_passed = 0, passed;

	if (argc == 0) {
		/* or allow this as "all"? */
		warnx("make_binding_object: command is too short");
		return (-1);
	}

	if (strcmp(argv[0], "IA") == 0) {
		if (put32(bpp, lenp, DHCP6CTL_BINDING_IA))
			goto fail;
		if ((passed = make_ia_object(argc - 1, argv + 1,
		    bpp, lenp)) < 0) {
			return (-1);
		}
		argc_passed += passed;
	} else {
		warn("unknown binding type: %s", argv[0]);
		return (-1);
	}

	argc_passed++;
	return (argc_passed);

  fail:
	warnx("make_binding_object: failed");
	return (-1);
}

static int
make_ia_object(int argc, char **argv, char **bpp, int *lenp)
{
	struct dhcp6ctl_iaspec iaspec;
	int duidlen, dummylen = 0;
	int argc_passed = 0;
	char *dummy = NULL;

	if (argc < 3) {
		/*
		 * Right now, we require all three parameters of
		 * <IA type, IAID, DUID>.  This should be more flexible in
		 * the future.
		 */
		warnx("command is too short for an IA spec");
		return (-1);
	}
	argc_passed += 3;

	memset(&iaspec, 0, sizeof(iaspec));

	if (strcmp(argv[0], "IA_PD") == 0)
		iaspec.type = htonl(DHCP6CTL_IA_PD);
	else if (strcmp(argv[0], "IA_NA") == 0)
		iaspec.type = htonl(DHCP6CTL_IA_NA);
	else {
		warnx("IA type not supported: %s", argv[0]);
		return (-1);
	}

	iaspec.id = htonl((u_int32_t)strtol(argv[1], NULL, 10));

	if (parse_duid(argv[2], &duidlen, &dummy, &dummylen))
		goto fail;
	iaspec.duidlen = htonl(duidlen);

	if (putval(bpp, lenp, &iaspec, sizeof(iaspec)))
		goto fail;

	if (parse_duid(argv[2], &duidlen, bpp, lenp))
		goto fail;

	return (argc_passed);

  fail:
	warnx("make_ia_object: failed");
	return (-1);
}

static int
parse_duid(char *str, int *lenp, char **bufp, int *buflenp)
{
	char *buf = *bufp;
	char *cp, *bp;
	int duidlen, slen, buflen;
	unsigned int x;

	/* calculate DUID len */
	slen = strlen(str);
	if (slen < 2)
		goto bad;
	duidlen = 1;
	slen -= 2;
	if ((slen % 3) != 0)
		goto bad;
	duidlen += (slen / 3);
	if (duidlen > 128) {
		warn("too long DUID (%d bytes)", duidlen);
		return (-1);
	}

	*lenp = duidlen;
	if (buf == NULL)
		return (0);

	buflen = *buflenp;
	if (buflen < duidlen)
		goto bad;

	for (cp = str, bp = buf; *cp != '\0';) {
		if (bp - buf >= buflen)
			goto bad;

		if (sscanf(cp, "%02x", &x) != 1)
			goto bad;
		*bp++ = x;
		cp += 2;

		switch (*cp) {
		case ':':
			cp++;
			break;
		case '\0':
			goto done;
		default:
			goto bad;
		}
	}
  done:
	*bufp = bp;
	return (0);

  bad:
	return (-1);
}

static void
usage(void)
{
	fprintf(stderr, "usage: dhcp6ctl [-C|-S] [-a ctladdr] [-k keyfile] "
	    "[-p ctlport] command...\n");

	exit(1);
}