relay.c revision 7c478bd95313f5f23a4c958a745db2134aa03244
/*
* CDDL HEADER START
*
* The contents of this file are subject to the terms of the
* Common Development and Distribution License, Version 1.0 only
* (the "License"). You may not use this file except in compliance
* with the License.
*
* You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
* or http://www.opensolaris.org/os/licensing.
* See the License for the specific language governing permissions
* and limitations under the License.
*
* When distributing Covered Code, include this CDDL HEADER in each
* file and include the License file at usr/src/OPENSOLARIS.LICENSE.
* If applicable, add the following below this CDDL HEADER, with the
* fields enclosed by brackets "[]" replaced with your own identifying
* information: Portions Copyright [yyyy] [name of copyright owner]
*
* CDDL HEADER END
*/
/*
* Copyright 1996-2003 Sun Microsystems, Inc. All rights reserved.
* Use is subject to license terms.
*/
#pragma ident "%Z%%M% %I% %E% SMI"
#include <stdio.h>
#include <stdlib.h>
#include <stdarg.h>
#include <sys/types.h>
#include <assert.h>
#include <sys/socket.h>
#include <sys/sockio.h>
#include <net/if.h>
#include <errno.h>
#include <netdb.h>
#include <string.h>
#include <sys/syslog.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <netinet/dhcp.h>
#include "dhcpd.h"
#include "per_dnet.h"
#include "interfaces.h"
#include <locale.h>
#define MAX_RELAY_IP 5 /* Maximum of destinations */
static struct in_addr relay_ip[MAX_RELAY_IP]; /* IPs of targets */
static struct in_addr relay_net[MAX_RELAY_IP]; /* target nets */
static int relay_reply(IF *, PKT_LIST *);
static int relay_request(IF *, PKT_LIST *);
/*
* This file contains the code which implements the BOOTP relay agent.
*/
/*
* Parse arguments. If an agument begins with a digit, then it's
* an IP address, otherwise it's a hostname which needs to be
* resolved into an IP address.
*
* Use the arguments to fill in relay_ip array.
*
* Only callable by main thread. MT UNSAFE
*/
int
relay_agent_init(char *args)
{
int i;
struct in_addr *ip;
struct hostent *hp;
char ntoab[INET_ADDRSTRLEN];
for (i = 0; i <= MAX_RELAY_IP; i++) {
if ((args = strtok(args, ",")) == NULL)
break; /* done */
/*
* If there's more than MAX_RELAY_IP addresses
* specified that's an error. If we can't
* resolve the host name, that's an error.
*/
if (i == MAX_RELAY_IP) {
(void) fprintf(stderr,
gettext("Too many relay agent destinations.\n"));
return (E2BIG);
}
if ((hp = gethostbyname(args)) == NULL) {
(void) fprintf(stderr, gettext(
"Invalid relay agent destination name: %s\n"),
args);
return (EINVAL);
}
/* LINTED [will be lw aligned] */
ip = (struct in_addr *)hp->h_addr;
/*
* Note: no way to guess at destination subnet mask,
* and verify that it's not a new broadcast addr.
*/
if (ip->s_addr == INADDR_ANY ||
ip->s_addr == INADDR_LOOPBACK ||
ip->s_addr == INADDR_BROADCAST) {
(void) fprintf(stderr, gettext("Relay destination \
cannot be 0, loopback, or broadcast address.\n"));
return (EINVAL);
}
relay_ip[i].s_addr = ip->s_addr;
ip = &relay_ip[i];
get_netmask(ip, &relay_net[i]);
relay_net[i].s_addr &= ip->s_addr;
if (verbose) {
(void) fprintf(stdout,
gettext("Relay destination: %s (%s)"),
inet_ntop(AF_INET, &relay_ip[i],
ntoab, sizeof (ntoab)), args);
(void) fprintf(stdout, gettext("\t\tnetwork: %s\n"),
inet_ntop(AF_INET, &relay_net[i],
ntoab, sizeof (ntoab)));
}
args = NULL; /* for next call to strtok() */
}
if (i == 0) {
/*
* Gotta specify at least one IP addr.
*/
(void) fprintf(stderr,
gettext("Specify at least one relay agent destination.\n"));
return (ENOENT);
}
if (i < MAX_RELAY_IP)
relay_ip[i].s_addr = NULL; /* terminate the list */
return (0);
}
/*
* Note: if_head_mtx must be held by caller, as the interface list is
* walked in relay_reply.
*
* MT SAFE
*/
int
relay_agent(IF *ifp, PKT_LIST *plp)
{
if (plp->pkt->op == BOOTREQUEST)
return (relay_request(ifp, plp));
return (relay_reply(ifp, plp));
}
/*
* MT SAFE
*/
static int
relay_request(IF *ifp, PKT_LIST *plp)
{
PKT *pkp;
struct sockaddr_in to;
struct in_addr ifnet, any;
int i;
char ntoab[INET_ADDRSTRLEN];
char buf[DN_MAX_CID_LEN], *msg;
pkp = plp->pkt;
if (pkp->giaddr.s_addr == 0L)
pkp->giaddr.s_addr = ifp->addr.s_addr;
pkp->hops++;
/*
* Send it on to the next relay(s)/servers
*/
to.sin_port = htons(IPPORT_BOOTPS + port_offset);
any.s_addr = htonl(INADDR_ANY);
(void) disp_cid(plp, buf, sizeof (buf));
for (i = 0; i < MAX_RELAY_IP; i++) {
if (relay_ip[i].s_addr == 0L)
break; /* we're done */
ifnet.s_addr = ifp->addr.s_addr & ifp->mask.s_addr;
if (relay_net[i].s_addr == ifnet.s_addr) {
if (verbose) {
dhcpmsg(LOG_INFO, "Target's network: \
%1$s is the same as client %2$s network, ignored.\n",
inet_ntop(AF_INET, &relay_net[i],
ntoab, sizeof (ntoab)),
buf);
}
continue; /* skip this target */
}
to.sin_addr.s_addr = relay_ip[i].s_addr;
if (to.sin_port == htons(IPPORT_BOOTPS + port_offset))
msg = "Relaying request %1$s to %2$s, server port.\n";
else
msg = "Relaying request %1$s to %2$s, client port.\n";
if (debug) {
dhcpmsg(LOG_INFO, msg, buf,
inet_ntop(AF_INET, &to.sin_addr,
ntoab, sizeof (ntoab)));
}
if (write_interface(ifp, pkp, plp->len, &to)) {
dhcpmsg(LOG_INFO, "Cannot relay request %1$s to %2$s\n",
buf, inet_ntop(AF_INET, &to.sin_addr,
ntoab, sizeof (ntoab)));
} else {
logtrans(P_BOOTP, L_RELAY_REQ, 0, any, to.sin_addr,
plp);
}
}
return (0);
}
/*
* Note: if_head_mtx must be held by caller, as the interface list is
* walked here.
*/
static int
relay_reply(IF *ifp, PKT_LIST *plp)
{
int err;
IF *tifp;
PKT *pkp = plp->pkt;
struct in_addr to;
char buf[DHCP_MAX_OPT_SIZE];
char ntoab_a[INET_ADDRSTRLEN], ntoab_b[INET_ADDRSTRLEN];
assert(MUTEX_HELD(&if_head_mtx));
if (pkp->giaddr.s_addr == 0L) {
/*
* Somehow we picked up a reply packet from a DHCP server
* on this net intended for a client on this net. Drop it.
*/
if (verbose) {
dhcpmsg(LOG_INFO,
"Reply packet without giaddr set ignored.\n");
}
return (0);
}
/*
* We can assume that the message came directly from a dhcp/bootp
* server to us, and we are to address it directly to the client.
*/
if (pkp->giaddr.s_addr != ifp->addr.s_addr) {
/*
* It is possible that this is a multihomed host. We'll
* check to see if this is the case, and handle it
* appropriately.
*/
for (tifp = if_head; tifp != NULL; tifp = tifp->next) {
if (tifp->addr.s_addr == pkp->giaddr.s_addr)
break;
}
if (tifp == NULL) {
if (verbose) {
dhcpmsg(LOG_INFO, "Received relayed reply \
not intended for this interface: %1$s giaddr: %2$s\n",
inet_ntop(AF_INET, &ifp->addr,
ntoab_a, sizeof (ntoab_a)),
inet_ntop(AF_INET, &pkp->giaddr,
ntoab_b, sizeof (ntoab_b)));
}
return (0);
} else
ifp = tifp;
}
(void) disp_cid(plp, buf, sizeof (buf));
pkp->hops++;
if (debug)
dhcpmsg(LOG_INFO, "Relaying reply to client %s\n", buf);
if ((ntohs(pkp->flags) & BCAST_MASK) == 0) {
if (pkp->yiaddr.s_addr == htonl(INADDR_ANY)) {
if (pkp->ciaddr.s_addr == htonl(INADDR_ANY)) {
dhcpmsg(LOG_INFO, "No destination IP \
address or network IP address; cannot send reply to client: %s.\n", buf);
return (0);
}
to.s_addr = pkp->ciaddr.s_addr;
} else
to.s_addr = pkp->yiaddr.s_addr;
}
if ((err = send_reply(ifp, pkp, plp->len, &to)) == 0)
logtrans(P_BOOTP, L_RELAY_REP, 0, ifp->addr, to, plp);
return (err);
}