common.c

DHCPv6协议在Linux操作系统下的一个客户端实现。

/*	$Id: common.c,v 1.19 2004/02/04 23:30:17 shemminger Exp $	*/
/*	ported from KAME: common.c,v 1.65 2002/12/06 01:41:29 suz Exp	*/

/*
 * Copyright (C) 1998 and 1999 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 <linux/sockios.h>
#include <sys/ioctl.h>

#if TIME_WITH_SYS_TIME
# include <sys/time.h>
# include <time.h>
#else
# if HAVE_SYS_TIME_H
#  include <sys/time.h>
# else
#  include <time.h>
# endif
#endif
#include <net/if.h>
#if defined(__FreeBSD__) && __FreeBSD__ >= 3
#include <net/if_var.h>
#endif
#include <net/if_arp.h>

#include <netinet/in.h>
#include <errno.h>
#include <limits.h>
#include <stdio.h>
#include <stdarg.h>
#include <syslog.h>
#include <stdlib.h>
#include <unistd.h>
#include <string.h>
#include <err.h>
#include <netdb.h>
#include <ifaddrs.h>
#include <resolv.h>

#ifdef HAVE_GETIFADDRS 
# ifdef HAVE_IFADDRS_H
#  define USE_GETIFADDRS
#  include <ifaddrs.h>
# endif
#endif

#include "queue.h"
#include "dhcp6.h"
#include "config.h"
#include "common.h"
#include "timer.h"
#include "lease.h"

int foreground;
int debug_thresh;
struct dhcp6_if *dhcp6_if;
struct dns_list dnslist;
static struct host_conf *host_conflist;
static int in6_matchflags __P((struct sockaddr *, char *, int));
ssize_t gethwid __P((char *, int, const char *, u_int16_t *));
static int get_assigned_ipv6addrs __P((char *, char *,
					struct dhcp6_optinfo *));
struct dhcp6_if *
find_ifconfbyname(const char *ifname)
{
	struct dhcp6_if *ifp;

	for (ifp = dhcp6_if; ifp; ifp = ifp->next) {
		if (strcmp(ifp->ifname, ifname) == 0)
			return (ifp);
	}

	return (NULL);
}

struct dhcp6_if *
find_ifconfbyid(unsigned int id)
{
	struct dhcp6_if *ifp;

	for (ifp = dhcp6_if; ifp; ifp = ifp->next) {
		if (ifp->ifid == id)
			return (ifp);
	}

	return (NULL);
}

struct host_conf *
find_hostconf(const struct duid *duid)
{
	struct host_conf *host;

	for (host = host_conflist; host; host = host->next) {
		if (host->duid.duid_len == duid->duid_len &&
		    memcmp(host->duid.duid_id, duid->duid_id,
			   host->duid.duid_len) == 0) {
			return (host);
		}
	}

	return (NULL);
}
void
ifinit(const char *ifname)
{
	struct dhcp6_if *ifp;

	if ((ifp = find_ifconfbyname(ifname)) != NULL) {
		dprintf(LOG_NOTICE, "%s" "duplicated interface: %s",
			FNAME, ifname);
		return;
	}

	if ((ifp = malloc(sizeof(*ifp))) == NULL) {
		dprintf(LOG_ERR, "%s" "malloc failed", FNAME);
		goto die;
	}
	memset(ifp, 0, sizeof(*ifp));

	TAILQ_INIT(&ifp->event_list);

	if ((ifp->ifname = strdup(ifname)) == NULL) {
		dprintf(LOG_ERR, "%s" "failed to copy ifname", FNAME);
		goto die;
	}

	if ((ifp->ifid = if_nametoindex(ifname)) == 0) {
		dprintf(LOG_ERR, "%s" "invalid interface(%s): %s", FNAME,
			ifname, strerror(errno));
		goto die;
	}
#ifdef HAVE_SCOPELIB
	if (inet_zoneid(AF_INET6, 2, ifname, &ifp->linkid)) {
		dprintf(LOG_ERR, "%s" "failed to get link ID for %s",
			FNAME, ifname);
		goto die;
	}
#else
	ifp->linkid = ifp->ifid; /* XXX */
#endif
	if (get_linklocal(ifname, &ifp->linklocal) < 0)
		goto die;
	ifp->next = dhcp6_if;
	dhcp6_if = ifp;
	return;

  die:
	exit(1);
}

int
dhcp6_copy_list(struct dhcp6_list *dst, 
		const struct dhcp6_list *src)
{
	const struct dhcp6_listval *ent;
	struct dhcp6_listval *dent;

	for (ent = TAILQ_FIRST(src); ent; ent = TAILQ_NEXT(ent, link)) {
		if ((dent = malloc(sizeof(*dent))) == NULL)
			goto fail;

		memset(dent, 0, sizeof(*dent));
		memcpy(&dent->uv, &ent->uv, sizeof(ent->uv));

		TAILQ_INSERT_TAIL(dst, dent, link);
	}

	return 0;

  fail:
	dhcp6_clear_list(dst);
	return -1;
}

void
dhcp6_clear_list(head)
	struct dhcp6_list *head;
{
	struct dhcp6_listval *v;

	while ((v = TAILQ_FIRST(head)) != NULL) {
		TAILQ_REMOVE(head, v, link);
		free(v);
	}

	return;
}

int
dhcp6_count_list(head)
	struct dhcp6_list *head;
{
	struct dhcp6_listval *v;
	int i;

	for (i = 0, v = TAILQ_FIRST(head); v; v = TAILQ_NEXT(v, link))
		i++;

	return i;
}

struct dhcp6_listval *
dhcp6_find_listval(head, val, type)
	struct dhcp6_list *head;
	void *val;
	dhcp6_listval_type_t type;
{
	struct dhcp6_listval *lv;

	for (lv = TAILQ_FIRST(head); lv; lv = TAILQ_NEXT(lv, link)) {
		switch(type) {
		case DHCP6_LISTVAL_NUM:
			if (lv->val_num == *(int *)val)
				return (lv);
			break;
		case DHCP6_LISTVAL_ADDR6:
			if (IN6_ARE_ADDR_EQUAL(&lv->val_addr6,
			    (struct in6_addr *)val)) {
				return (lv);
			}
			break;
		case DHCP6_LISTVAL_DHCP6ADDR:
			if (IN6_ARE_ADDR_EQUAL(&lv->val_dhcp6addr.addr,
			    &((struct dhcp6_addr *)val)->addr) && 
			    (lv->val_dhcp6addr.plen == ((struct dhcp6_addr *)val)->plen)) {
				return (lv);
			}
			break;
		}
	}

	return (NULL);
}

struct dhcp6_listval *
dhcp6_add_listval(head, val, type)
	struct dhcp6_list *head;
	void *val;
	dhcp6_listval_type_t type;
{
	struct dhcp6_listval *lv;

	if ((lv = malloc(sizeof(*lv))) == NULL) {
		dprintf(LOG_ERR, "%s" "failed to allocate memory for list "
		    "entry", FNAME);
		return (NULL);
	}
	memset(lv, 0, sizeof(*lv));

	switch(type) {
	case DHCP6_LISTVAL_NUM:
		lv->val_num = *(int *)val;
		break;
	case DHCP6_LISTVAL_ADDR6:
		lv->val_addr6 = *(struct in6_addr *)val;
		break;
	case DHCP6_LISTVAL_DHCP6ADDR:
		lv->val_dhcp6addr = *(struct dhcp6_addr *)val;
		break;
	default:
		dprintf(LOG_ERR, "%s" "unexpected list value type (%d)",
		    FNAME, type);
		return (NULL);
	}
	TAILQ_INSERT_TAIL(head, lv, link);
	return (lv);
}

struct dhcp6_event *
dhcp6_create_event(ifp, state)
	struct dhcp6_if *ifp;
	int state;
{
	struct dhcp6_event *ev;

	if ((ev = malloc(sizeof(*ev))) == NULL) {
		dprintf(LOG_ERR, "%s" "failed to allocate memory for an event",
			FNAME);
		return (NULL);
	}
	/* for safety */
	memset(ev, 0, sizeof(*ev));
	ev->serverid.duid_id = NULL;
	
	ev->ifp = ifp;
	ev->state = state;
	TAILQ_INIT(&ev->data_list);
	dprintf(LOG_DEBUG, "%s" "create an event %p xid %d for state %d", 
		FNAME, ev, ev->xid, ev->state);
	return (ev);
}

void
dhcp6_remove_event(ev)
	struct dhcp6_event *ev;
{
	dprintf(LOG_DEBUG, "%s" "removing an event %p on %s, state=%d, xid=%x", FNAME,
		ev, ev->ifp->ifname, ev->state, ev->xid);

	if (!TAILQ_EMPTY(&ev->data_list)) {
		dprintf(LOG_ERR, "%s" "assumption failure: "
			"event data list is not empty", FNAME);
		exit(1);
	}
	if (ev->serverid.duid_id != NULL)
		duidfree(&ev->serverid);
	if (ev->timer)
		dhcp6_remove_timer(ev->timer);
	TAILQ_REMOVE(&ev->ifp->event_list, ev, link);
	free(ev);
	/* XXX: for safety */
	ev = NULL;
}


int
getifaddr(addr, ifnam, prefix, plen, strong, ignoreflags)
	struct in6_addr *addr;
	char *ifnam;
	struct in6_addr *prefix;
	int plen;
	int strong;		/* if strong host model is required or not */
	int ignoreflags;
{
	struct ifaddrs *ifap, *ifa;
	struct sockaddr_in6 sin6;
	int error = -1;

	if (getifaddrs(&ifap) != 0) {
		err(1, "getifaddr: getifaddrs");
		/*NOTREACHED*/
	}

	for (ifa = ifap; ifa; ifa = ifa->ifa_next) {
		int s1, s2;

		if (strong && strcmp(ifnam, ifa->ifa_name) != 0)
			continue;

		/* in any case, ignore interfaces in different scope zones. */
		if ((s1 = in6_addrscopebyif(prefix, ifnam)) < 0 ||
		    (s2 = in6_addrscopebyif(prefix, ifa->ifa_name)) < 0 ||
		     s1 != s2)
			continue;

		if (ifa->ifa_addr->sa_family != AF_INET6)
			continue;
		if (sizeof(*(ifa->ifa_addr)) > sizeof(sin6))
			continue;

		if (in6_matchflags(ifa->ifa_addr, ifa->ifa_name, ignoreflags))
			continue;

		memcpy(&sin6, ifa->ifa_addr, sizeof(sin6));
#ifdef __KAME__
		if (IN6_IS_ADDR_LINKLOCAL(&sin6.sin6_addr)) {
			sin6.sin6_addr.s6_addr[2] = 0;
			sin6.sin6_addr.s6_addr[3] = 0;
		}
#endif
		if (plen % 8 == 0) {
			if (memcmp(&sin6.sin6_addr, prefix, plen / 8) != 0)
				continue;
		} else {
			struct in6_addr a, m;
			int i;

			memcpy(&a, &sin6.sin6_addr, sizeof(a));
			memset(&m, 0, sizeof(m));
			memset(&m, 0xff, plen / 8);
			m.s6_addr[plen / 8] = (0xff00 >> (plen % 8)) & 0xff;
			for (i = 0; i < sizeof(a); i++)
				a.s6_addr[i] &= m.s6_addr[i];

			if (memcmp(&a, prefix, plen / 8) != 0 ||
			    a.s6_addr[plen / 8] !=
			    (prefix->s6_addr[plen / 8] & m.s6_addr[plen / 8]))
				continue;
		}
		memcpy(addr, &sin6.sin6_addr, sizeof(*addr));
#ifdef __KAME__
		if (IN6_IS_ADDR_LINKLOCAL(addr))
			addr->s6_addr[2] = addr->s6_addr[3] = 0; 
#endif
		error = 0;
		break;
	}

	freeifaddrs(ifap);
	return (error);
}

int
in6_addrscopebyif(addr, ifnam)
	struct in6_addr *addr;
	char *ifnam;
{
	u_int ifindex; 

	if ((ifindex = if_nametoindex(ifnam)) == 0)
		return (-1);

	if (IN6_IS_ADDR_LINKLOCAL(addr) || IN6_IS_ADDR_MC_LINKLOCAL(addr))
		return (ifindex);

	if (IN6_IS_ADDR_SITELOCAL(addr) || IN6_IS_ADDR_MC_SITELOCAL(addr))
		return (1);	/* XXX */

	if (IN6_IS_ADDR_MC_ORGLOCAL(addr))
		return (1);	/* XXX */

	return (1);		/* treat it as global */
}

/* XXX: this code assumes getifaddrs(3) */
const char *
getdev(addr)
	struct sockaddr_in6 *addr;
{
	struct ifaddrs *ifap, *ifa;
	struct sockaddr_in6 *a6;
	static char ret_ifname[IFNAMSIZ];

	if (getifaddrs(&ifap) != 0) {
		err(1, "getdev: getifaddrs");
		/* NOTREACHED */
	}

	for (ifa = ifap; ifa; ifa = ifa->ifa_next) {
		if (ifa->ifa_addr->sa_family != AF_INET6)
			continue;

		a6 = (struct sockaddr_in6 *)ifa->ifa_addr;
		if (!IN6_ARE_ADDR_EQUAL(&a6->sin6_addr, &addr->sin6_addr) ||
		    a6->sin6_scope_id != addr->sin6_scope_id)
			continue;

		break;
	}

	if (ifa)
		strlcpy(ret_ifname, ifa->ifa_name, sizeof(ret_ifname));
	freeifaddrs(ifap);

	return (ifa ? ret_ifname : NULL);
}

int
transmit_sa(s, sa, buf, len)
	int s;
	struct sockaddr_in6 *sa;
	char *buf;
	size_t len;
{
	int error;

	error = sendto(s, buf, len, MSG_DONTROUTE, (struct sockaddr *)sa, sizeof(*sa));

	return (error != len) ? -1 : 0;
}

long
random_between(x, y)
	long x;
	long y;
{
	long ratio;

	ratio = 1 << 16;
	while ((y - x) * ratio < (y - x))