OpenBSD-4.6/usr.sbin/dhcpd/bootp.c
/* $OpenBSD: bootp.c,v 1.13 2006/03/13 19:57:42 otto Exp $ */
/*
* BOOTP Protocol support.
*/
/*
* Copyright (c) 1995, 1996, 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''.
*/
#include "dhcpd.h"
void
bootp(struct packet *packet)
{
struct host_decl *hp, *host = NULL;
struct packet outgoing;
struct dhcp_packet raw;
struct sockaddr_in to;
struct in_addr from;
struct tree_cache *options[256];
struct subnet *subnet = NULL;
struct lease *lease;
struct iaddr ip_address;
int i;
if (packet->raw->op != BOOTREQUEST)
return;
note("BOOTREQUEST from %s via %s%s", print_hw_addr(packet->raw->htype,
packet->raw->hlen, packet->raw->chaddr),
packet->raw->giaddr.s_addr ? inet_ntoa(packet->raw->giaddr) :
packet->interface->name,
packet->options_valid ? "" : " (non-rfc1048)");
if (!locate_network(packet))
return;
hp = find_hosts_by_haddr(packet->raw->htype, packet->raw->chaddr,
packet->raw->hlen);
lease = find_lease(packet, packet->shared_network, 0);
/*
* Find an IP address in the host_decl that matches the specified
* network.
*/
if (hp)
subnet = find_host_for_network(&hp, &ip_address,
packet->shared_network);
if (!subnet) {
/*
* We didn't find an applicable host declaration. Just in case
* we may be able to dynamically assign an address, see if
* there's a host declaration that doesn't have an ip address
* associated with it.
*/
if (hp)
for (; hp; hp = hp->n_ipaddr)
if (!hp->fixed_addr) {
host = hp;
break;
}
if (host && (!host->group->allow_booting)) {
note("Ignoring excluded BOOTP client %s", host->name ?
host->name : print_hw_addr (packet->raw->htype,
packet->raw->hlen, packet->raw->chaddr));
return;
}
if (host && (!host->group->allow_bootp)) {
note("Ignoring BOOTP request from client %s",
host->name ? host->name :
print_hw_addr(packet->raw->htype,
packet->raw->hlen, packet->raw->chaddr));
return;
}
/*
* If we've been told not to boot unknown clients, and we didn't
* find any host record for this client, ignore it.
*/
if (!host &&
!(packet->shared_network->group->boot_unknown_clients)) {
note("Ignoring unknown BOOTP client %s via %s",
print_hw_addr(packet->raw->htype,
packet->raw->hlen, packet->raw->chaddr),
packet->raw->giaddr.s_addr ?
inet_ntoa(packet->raw->giaddr) :
packet->interface->name);
return;
}
/*
* If we've been told not to boot with bootp on this network,
* ignore it.
*/
if (!host &&
!(packet->shared_network->group->allow_bootp)) {
note("Ignoring BOOTP request from client %s via %s",
print_hw_addr(packet->raw->htype,
packet->raw->hlen, packet->raw->chaddr),
packet->raw->giaddr.s_addr ?
inet_ntoa(packet->raw->giaddr) :
packet->interface->name);
return;
}
/*
* If the packet is from a host we don't know and there are no
* dynamic bootp addresses on the network it came in on, drop
* it on the floor.
*/
if (!(packet->shared_network->group->dynamic_bootp)) {
lose:
note("No applicable record for BOOTP host %s via %s",
print_hw_addr(packet->raw->htype,
packet->raw->hlen, packet->raw->chaddr),
packet->raw->giaddr.s_addr ?
inet_ntoa(packet->raw->giaddr) :
packet->interface->name);
return;
}
/*
* If a lease has already been assigned to this client and it's
* still okay to use dynamic bootp on that lease, reassign it.
*/
if (lease) {
/*
* If this lease can be used for dynamic bootp, do so.
*/
if ((lease->flags & DYNAMIC_BOOTP_OK)) {
/*
* If it's not a DYNAMIC_BOOTP lease, release it
* before reassigning it so that we don't get a
* lease conflict.
*/
if (!(lease->flags & BOOTP_LEASE))
release_lease(lease);
lease->host = host;
ack_lease(packet, lease, 0, 0);
return;
}
/*
* If dynamic BOOTP is no longer allowed for this
* lease, set it free.
*/
release_lease(lease);
}
/*
* If there are dynamic bootp addresses that might be
* available, try to snag one.
*/
for (lease = packet->shared_network->last_lease;
lease && lease->ends <= cur_time;
lease = lease->prev) {
if ((lease->flags & DYNAMIC_BOOTP_OK)) {
lease->host = host;
ack_lease(packet, lease, 0, 0);
return;
}
}
goto lose;
}
/* Make sure we're allowed to boot this client. */
if (hp && (!hp->group->allow_booting)) {
note("Ignoring excluded BOOTP client %s", hp->name);
return;
}
/* Make sure we're allowed to boot this client with bootp. */
if (hp && (!hp->group->allow_bootp)) {
note("Ignoring BOOTP request from client %s", hp->name);
return;
}
/* Set up the outgoing packet... */
memset(&outgoing, 0, sizeof outgoing);
memset(&raw, 0, sizeof raw);
outgoing.raw = &raw;
/*
* If we didn't get a known vendor magic number on the way in, just
* copy the input options to the output.
*/
if (!packet->options_valid && !subnet->group->always_reply_rfc1048 &&
(!hp || !hp->group->always_reply_rfc1048)) {
memcpy(outgoing.raw->options, packet->raw->options,
DHCP_OPTION_LEN);
outgoing.packet_length = BOOTP_MIN_LEN;
} else {
struct tree_cache netmask_tree; /* -- RBF */
/*
* Come up with a list of options that we want to send to this
* client. Start with the per-subnet options, and then override
* those with client-specific options.
*/
memcpy(options, subnet->group->options, sizeof(options));
for (i = 0; i < 256; i++)
if (hp->group->options[i])
options[i] = hp->group->options[i];
/*
* Use the subnet mask from the subnet declaration if no other
* mask has been provided.
*/
if (!options[DHO_SUBNET_MASK]) {
options[DHO_SUBNET_MASK] = &netmask_tree;
netmask_tree.flags = TC_TEMPORARY;
netmask_tree.value = lease->subnet->netmask.iabuf;
netmask_tree.len = lease->subnet->netmask.len;
netmask_tree.buf_size = lease->subnet->netmask.len;
netmask_tree.timeout = -1;
netmask_tree.tree = NULL;
}
/*
* Pack the options into the buffer. Unlike DHCP, we can't pack
* options into the filename and server name buffers.
*/
outgoing.packet_length = cons_options(packet, outgoing.raw,
0, options, 0, 0, 1, NULL, 0);
if (outgoing.packet_length < BOOTP_MIN_LEN)
outgoing.packet_length = BOOTP_MIN_LEN;
}
/* Take the fields that we care about... */
raw.op = BOOTREPLY;
raw.htype = packet->raw->htype;
raw.hlen = packet->raw->hlen;
memcpy(raw.chaddr, packet->raw->chaddr, sizeof(raw.chaddr));
raw.hops = packet->raw->hops;
raw.xid = packet->raw->xid;
raw.secs = packet->raw->secs;
raw.flags = packet->raw->flags;
raw.ciaddr = packet->raw->ciaddr;
memcpy(&raw.yiaddr, ip_address.iabuf, sizeof(raw.yiaddr));
/* Figure out the address of the next server. */
if (hp && hp->group->next_server.len)
memcpy(&raw.siaddr, hp->group->next_server.iabuf, 4);
else if (subnet->group->next_server.len)
memcpy(&raw.siaddr, subnet->group->next_server.iabuf, 4);
else if (subnet->interface_address.len)
memcpy(&raw.siaddr, subnet->interface_address.iabuf, 4);
else
raw.siaddr = packet->interface->primary_address;
raw.giaddr = packet->raw->giaddr;
if (hp->group->server_name)
strncpy(raw.sname, hp->group->server_name, sizeof(raw.sname));
else if (subnet->group->server_name)
strncpy(raw.sname, subnet->group->server_name,
sizeof(raw.sname));
if (hp->group->filename)
strncpy(raw.file, hp->group->filename, sizeof(raw.file));
else if (subnet->group->filename)
strncpy(raw.file, subnet->group->filename, sizeof(raw.file));
else
memcpy(raw.file, packet->raw->file, sizeof(raw.file));
from = packet->interface->primary_address;
/* Report what we're doing... */
note("BOOTREPLY for %s to %s (%s) via %s", piaddr(ip_address),
hp->name, print_hw_addr(packet->raw->htype, packet->raw->hlen,
packet->raw->chaddr), packet->raw->giaddr.s_addr ?
inet_ntoa(packet->raw->giaddr) : packet->interface->name);
/* Set up the parts of the address that are in common. */
memset(&to, 0, sizeof(to));
to.sin_family = AF_INET;
#ifdef HAVE_SA_LEN
to.sin_len = sizeof(to);
#endif
/* If this was gatewayed, send it back to the gateway... */
if (raw.giaddr.s_addr) {
to.sin_addr = raw.giaddr;
to.sin_port = server_port;
(void) send_packet(packet->interface, &raw,
outgoing.packet_length, from, &to, packet->haddr);
return;
}
/*
* If it comes from a client that already knows its address and is not
* requesting a broadcast response, and we can unicast to a client
* without using the ARP protocol, sent it directly to that client.
*/
else if (!(raw.flags & htons(BOOTP_BROADCAST))) {
to.sin_addr = raw.yiaddr;
to.sin_port = client_port;
} else {
/* Otherwise, broadcast it on the local network. */
to.sin_addr.s_addr = INADDR_BROADCAST;
to.sin_port = client_port; /* XXX */
}
errno = 0;
(void) send_packet(packet->interface, &raw,
outgoing.packet_length, from, &to, packet->haddr);
}