+++ /dev/null
-/* serverpacket.c
- *
- * Construct and send DHCP server packets
- *
- * Russ Dill <Russ.Dill@asu.edu> July 2001
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation; either version 2 of the License, or
- * (at your option) any later version.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program; if not, write to the Free Software
- * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
- */
-
-#include <sys/socket.h>
-#include <netinet/in.h>
-#include <arpa/inet.h>
-#include <string.h>
-#include <time.h>
-
-#include "serverpacket.h"
-#include "dhcpd.h"
-#include "options.h"
-#include "common.h"
-#include "static_leases.h"
-
-/* send a packet to giaddr using the kernel ip stack */
-static int send_packet_to_relay(struct dhcpMessage *payload)
-{
- DEBUG(LOG_INFO, "Forwarding packet to relay");
-
- return kernel_packet(payload, server_config.server, SERVER_PORT,
- payload->giaddr, SERVER_PORT);
-}
-
-
-/* send a packet to a specific arp address and ip address by creating our own ip packet */
-static int send_packet_to_client(struct dhcpMessage *payload, int force_broadcast)
-{
- uint8_t *chaddr;
- uint32_t ciaddr;
-
- if (force_broadcast) {
- DEBUG(LOG_INFO, "broadcasting packet to client (NAK)");
- ciaddr = INADDR_BROADCAST;
- chaddr = MAC_BCAST_ADDR;
- } else if (payload->ciaddr) {
- DEBUG(LOG_INFO, "unicasting packet to client ciaddr");
- ciaddr = payload->ciaddr;
- chaddr = payload->chaddr;
- } else if (ntohs(payload->flags) & BROADCAST_FLAG) {
- DEBUG(LOG_INFO, "broadcasting packet to client (requested)");
- ciaddr = INADDR_BROADCAST;
- chaddr = MAC_BCAST_ADDR;
- } else {
- DEBUG(LOG_INFO, "unicasting packet to client yiaddr");
- ciaddr = payload->yiaddr;
- chaddr = payload->chaddr;
- }
- return raw_packet(payload, server_config.server, SERVER_PORT,
- ciaddr, CLIENT_PORT, chaddr, server_config.ifindex);
-}
-
-
-/* send a dhcp packet, if force broadcast is set, the packet will be broadcast to the client */
-static int send_packet(struct dhcpMessage *payload, int force_broadcast)
-{
- int ret;
-
- if (payload->giaddr)
- ret = send_packet_to_relay(payload);
- else ret = send_packet_to_client(payload, force_broadcast);
- return ret;
-}
-
-
-static void init_packet(struct dhcpMessage *packet, struct dhcpMessage *oldpacket, char type)
-{
- init_header(packet, type);
- packet->xid = oldpacket->xid;
- memcpy(packet->chaddr, oldpacket->chaddr, 16);
- packet->flags = oldpacket->flags;
- packet->giaddr = oldpacket->giaddr;
- packet->ciaddr = oldpacket->ciaddr;
- add_simple_option(packet->options, DHCP_SERVER_ID, server_config.server);
-}
-
-
-/* add in the bootp options */
-static void add_bootp_options(struct dhcpMessage *packet)
-{
- packet->siaddr = server_config.siaddr;
- if (server_config.sname)
- strncpy(packet->sname, server_config.sname, sizeof(packet->sname) - 1);
- if (server_config.boot_file)
- strncpy(packet->file, server_config.boot_file, sizeof(packet->file) - 1);
-}
-
-
-/* send a DHCP OFFER to a DHCP DISCOVER */
-int sendOffer(struct dhcpMessage *oldpacket)
-{
- struct dhcpMessage packet;
- struct dhcpOfferedAddr *lease = NULL;
- uint32_t req_align, lease_time_align = server_config.lease;
- uint8_t *req, *lease_time;
- struct option_set *curr;
- struct in_addr addr;
-
- uint32_t static_lease_ip;
-
- init_packet(&packet, oldpacket, DHCPOFFER);
-
- static_lease_ip = getIpByMac(server_config.static_leases, oldpacket->chaddr);
-
- /* ADDME: if static, short circuit */
- if(!static_lease_ip)
- {
- /* the client is in our lease/offered table */
- if ((lease = find_lease_by_chaddr(oldpacket->chaddr))) {
- if (!lease_expired(lease))
- lease_time_align = lease->expires - time(0);
- packet.yiaddr = lease->yiaddr;
-
- /* Or the client has a requested ip */
- } else if ((req = get_option(oldpacket, DHCP_REQUESTED_IP)) &&
-
- /* Don't look here (ugly hackish thing to do) */
- memcpy(&req_align, req, 4) &&
-
- /* and the ip is in the lease range */
- ntohl(req_align) >= ntohl(server_config.start) &&
- ntohl(req_align) <= ntohl(server_config.end) &&
-
- !static_lease_ip && /* Check that its not a static lease */
- /* and is not already taken/offered */
- ((!(lease = find_lease_by_yiaddr(req_align)) ||
-
- /* or its taken, but expired */ /* ADDME: or maybe in here */
- lease_expired(lease)))) {
- packet.yiaddr = req_align; /* FIXME: oh my, is there a host using this IP? */
-
- /* otherwise, find a free IP */
- } else {
- /* Is it a static lease? (No, because find_address skips static lease) */
- packet.yiaddr = find_address(0);
-
- /* try for an expired lease */
- if (!packet.yiaddr) packet.yiaddr = find_address(1);
- }
-
- if(!packet.yiaddr) {
- LOG(LOG_WARNING, "no IP addresses to give -- OFFER abandoned");
- return -1;
- }
-
- if (!add_lease(packet.chaddr, packet.yiaddr, server_config.offer_time)) {
- LOG(LOG_WARNING, "lease pool is full -- OFFER abandoned");
- return -1;
- }
-
- if ((lease_time = get_option(oldpacket, DHCP_LEASE_TIME))) {
- memcpy(&lease_time_align, lease_time, 4);
- lease_time_align = ntohl(lease_time_align);
- if (lease_time_align > server_config.lease)
- lease_time_align = server_config.lease;
- }
-
- /* Make sure we aren't just using the lease time from the previous offer */
- if (lease_time_align < server_config.min_lease)
- lease_time_align = server_config.lease;
- }
- /* ADDME: end of short circuit */
- else
- {
- /* It is a static lease... use it */
- packet.yiaddr = static_lease_ip;
- }
-
- add_simple_option(packet.options, DHCP_LEASE_TIME, htonl(lease_time_align));
-
- curr = server_config.options;
- while (curr) {
- if (curr->data[OPT_CODE] != DHCP_LEASE_TIME)
- add_option_string(packet.options, curr->data);
- curr = curr->next;
- }
-
- add_bootp_options(&packet);
-
- addr.s_addr = packet.yiaddr;
- LOG(LOG_INFO, "sending OFFER of %s", inet_ntoa(addr));
- return send_packet(&packet, 0);
-}
-
-
-int sendNAK(struct dhcpMessage *oldpacket)
-{
- struct dhcpMessage packet;
-
- init_packet(&packet, oldpacket, DHCPNAK);
-
- DEBUG(LOG_INFO, "sending NAK");
- return send_packet(&packet, 1);
-}
-
-
-int sendACK(struct dhcpMessage *oldpacket, uint32_t yiaddr)
-{
- struct dhcpMessage packet;
- struct option_set *curr;
- uint8_t *lease_time;
- uint32_t lease_time_align = server_config.lease;
- struct in_addr addr;
-
- init_packet(&packet, oldpacket, DHCPACK);
- packet.yiaddr = yiaddr;
-
- if ((lease_time = get_option(oldpacket, DHCP_LEASE_TIME))) {
- memcpy(&lease_time_align, lease_time, 4);
- lease_time_align = ntohl(lease_time_align);
- if (lease_time_align > server_config.lease)
- lease_time_align = server_config.lease;
- else if (lease_time_align < server_config.min_lease)
- lease_time_align = server_config.lease;
- }
-
- add_simple_option(packet.options, DHCP_LEASE_TIME, htonl(lease_time_align));
-
- curr = server_config.options;
- while (curr) {
- if (curr->data[OPT_CODE] != DHCP_LEASE_TIME)
- add_option_string(packet.options, curr->data);
- curr = curr->next;
- }
-
- add_bootp_options(&packet);
-
- addr.s_addr = packet.yiaddr;
- LOG(LOG_INFO, "sending ACK to %s", inet_ntoa(addr));
-
- if (send_packet(&packet, 0) < 0)
- return -1;
-
- add_lease(packet.chaddr, packet.yiaddr, lease_time_align);
-
- return 0;
-}
-
-
-int send_inform(struct dhcpMessage *oldpacket)
-{
- struct dhcpMessage packet;
- struct option_set *curr;
-
- init_packet(&packet, oldpacket, DHCPACK);
-
- curr = server_config.options;
- while (curr) {
- if (curr->data[OPT_CODE] != DHCP_LEASE_TIME)
- add_option_string(packet.options, curr->data);
- curr = curr->next;
- }
-
- add_bootp_options(&packet);
-
- return send_packet(&packet, 0);
-}
projects / grml-terminalserver.git / blobdiff