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    Contents of /trunk/mkinitrd-magellan/busybox/networking/udhcp/serverpacket.c

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    Revision 532 - (show annotations) (download)
    Sat Sep 1 22:45:15 2007 UTC (16 years, 8 months ago) by niro
    File MIME type: text/plain
    File size: 7673 byte(s) 
    -import if magellan mkinitrd; it is a fork of redhats mkinitrd-5.0.8 with all magellan patches and features; deprecates magellan-src/mkinitrd
    1 /* vi: set sw=4 ts=4: */
    2 /* serverpacket.c
    3 *
    4 * Construct and send DHCP server packets
    5 *
    6 * Russ Dill <Russ.Dill@asu.edu> July 2001
    7 *
    8 * This program is free software; you can redistribute it and/or modify
    9 * it under the terms of the GNU General Public License as published by
    10 * the Free Software Foundation; either version 2 of the License, or
    11 * (at your option) any later version.
    12 *
    13 * This program is distributed in the hope that it will be useful,
    14 * but WITHOUT ANY WARRANTY; without even the implied warranty of
    15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
    16 * GNU General Public License for more details.
    17 *
    18 * You should have received a copy of the GNU General Public License
    19 * along with this program; if not, write to the Free Software
    20 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
    21 */
    22
    23 #include "common.h"
    24 #include "dhcpd.h"
    25 #include "options.h"
    26
    27
    28 /* send a packet to giaddr using the kernel ip stack */
    29 static int send_packet_to_relay(struct dhcpMessage *payload)
    30 {
    31 DEBUG("Forwarding packet to relay");
    32
    33 return udhcp_kernel_packet(payload, server_config.server, SERVER_PORT,
    34 payload->giaddr, SERVER_PORT);
    35 }
    36
    37
    38 /* send a packet to a specific arp address and ip address by creating our own ip packet */
    39 static int send_packet_to_client(struct dhcpMessage *payload, int force_broadcast)
    40 {
    41 uint8_t *chaddr;
    42 uint32_t ciaddr;
    43
    44 if (force_broadcast) {
    45 DEBUG("broadcasting packet to client (NAK)");
    46 ciaddr = INADDR_BROADCAST;
    47 chaddr = MAC_BCAST_ADDR;
    48 } else if (payload->ciaddr) {
    49 DEBUG("unicasting packet to client ciaddr");
    50 ciaddr = payload->ciaddr;
    51 chaddr = payload->chaddr;
    52 } else if (ntohs(payload->flags) & BROADCAST_FLAG) {
    53 DEBUG("broadcasting packet to client (requested)");
    54 ciaddr = INADDR_BROADCAST;
    55 chaddr = MAC_BCAST_ADDR;
    56 } else {
    57 DEBUG("unicasting packet to client yiaddr");
    58 ciaddr = payload->yiaddr;
    59 chaddr = payload->chaddr;
    60 }
    61 return udhcp_raw_packet(payload, server_config.server, SERVER_PORT,
    62 ciaddr, CLIENT_PORT, chaddr, server_config.ifindex);
    63 }
    64
    65
    66 /* send a dhcp packet, if force broadcast is set, the packet will be broadcast to the client */
    67 static int send_packet(struct dhcpMessage *payload, int force_broadcast)
    68 {
    69 int ret;
    70
    71 if (payload->giaddr)
    72 ret = send_packet_to_relay(payload);
    73 else ret = send_packet_to_client(payload, force_broadcast);
    74 return ret;
    75 }
    76
    77
    78 static void init_packet(struct dhcpMessage *packet, struct dhcpMessage *oldpacket, char type)
    79 {
    80 udhcp_init_header(packet, type);
    81 packet->xid = oldpacket->xid;
    82 memcpy(packet->chaddr, oldpacket->chaddr, 16);
    83 packet->flags = oldpacket->flags;
    84 packet->giaddr = oldpacket->giaddr;
    85 packet->ciaddr = oldpacket->ciaddr;
    86 add_simple_option(packet->options, DHCP_SERVER_ID, server_config.server);
    87 }
    88
    89
    90 /* add in the bootp options */
    91 static void add_bootp_options(struct dhcpMessage *packet)
    92 {
    93 packet->siaddr = server_config.siaddr;
    94 if (server_config.sname)
    95 strncpy((char*)packet->sname, server_config.sname, sizeof(packet->sname) - 1);
    96 if (server_config.boot_file)
    97 strncpy((char*)packet->file, server_config.boot_file, sizeof(packet->file) - 1);
    98 }
    99
    100
    101 /* send a DHCP OFFER to a DHCP DISCOVER */
    102 int sendOffer(struct dhcpMessage *oldpacket)
    103 {
    104 struct dhcpMessage packet;
    105 struct dhcpOfferedAddr *lease = NULL;
    106 uint32_t req_align, lease_time_align = server_config.lease;
    107 uint8_t *req, *lease_time;
    108 struct option_set *curr;
    109 struct in_addr addr;
    110
    111 uint32_t static_lease_ip;
    112
    113 init_packet(&packet, oldpacket, DHCPOFFER);
    114
    115 static_lease_ip = getIpByMac(server_config.static_leases, oldpacket->chaddr);
    116
    117 /* ADDME: if static, short circuit */
    118 if (!static_lease_ip) {
    119 /* the client is in our lease/offered table */
    120 lease = find_lease_by_chaddr(oldpacket->chaddr);
    121 if (lease) {
    122 if (!lease_expired(lease))
    123 lease_time_align = lease->expires - time(0);
    124 packet.yiaddr = lease->yiaddr;
    125
    126 /* Or the client has a requested ip */
    127 } else if ((req = get_option(oldpacket, DHCP_REQUESTED_IP))
    128 /* Don't look here (ugly hackish thing to do) */
    129 && memcpy(&req_align, req, 4)
    130 /* and the ip is in the lease range */
    131 && ntohl(req_align) >= ntohl(server_config.start)
    132 && ntohl(req_align) <= ntohl(server_config.end)
    133 && !static_lease_ip /* Check that its not a static lease */
    134 /* and is not already taken/offered */
    135 && (!(lease = find_lease_by_yiaddr(req_align))
    136 /* or its taken, but expired */ /* ADDME: or maybe in here */
    137 || lease_expired(lease))
    138 ) {
    139 packet.yiaddr = req_align; /* FIXME: oh my, is there a host using this IP? */
    140 /* otherwise, find a free IP */
    141 } else {
    142 /* Is it a static lease? (No, because find_address skips static lease) */
    143 packet.yiaddr = find_address(0);
    144 /* try for an expired lease */
    145 if (!packet.yiaddr) packet.yiaddr = find_address(1);
    146 }
    147
    148 if (!packet.yiaddr) {
    149 bb_error_msg("no IP addresses to give - OFFER abandoned");
    150 return -1;
    151 }
    152 if (!add_lease(packet.chaddr, packet.yiaddr, server_config.offer_time)) {
    153 bb_error_msg("lease pool is full - OFFER abandoned");
    154 return -1;
    155 }
    156 lease_time = get_option(oldpacket, DHCP_LEASE_TIME);
    157 if (lease_time) {
    158 memcpy(&lease_time_align, lease_time, 4);
    159 lease_time_align = ntohl(lease_time_align);
    160 if (lease_time_align > server_config.lease)
    161 lease_time_align = server_config.lease;
    162 }
    163
    164 /* Make sure we aren't just using the lease time from the previous offer */
    165 if (lease_time_align < server_config.min_lease)
    166 lease_time_align = server_config.lease;
    167 /* ADDME: end of short circuit */
    168 } else {
    169 /* It is a static lease... use it */
    170 packet.yiaddr = static_lease_ip;
    171 }
    172
    173 add_simple_option(packet.options, DHCP_LEASE_TIME, htonl(lease_time_align));
    174
    175 curr = server_config.options;
    176 while (curr) {
    177 if (curr->data[OPT_CODE] != DHCP_LEASE_TIME)
    178 add_option_string(packet.options, curr->data);
    179 curr = curr->next;
    180 }
    181
    182 add_bootp_options(&packet);
    183
    184 addr.s_addr = packet.yiaddr;
    185 bb_info_msg("Sending OFFER of %s", inet_ntoa(addr));
    186 return send_packet(&packet, 0);
    187 }
    188
    189
    190 int sendNAK(struct dhcpMessage *oldpacket)
    191 {
    192 struct dhcpMessage packet;
    193
    194 init_packet(&packet, oldpacket, DHCPNAK);
    195
    196 DEBUG("Sending NAK");
    197 return send_packet(&packet, 1);
    198 }
    199
    200
    201 int sendACK(struct dhcpMessage *oldpacket, uint32_t yiaddr)
    202 {
    203 struct dhcpMessage packet;
    204 struct option_set *curr;
    205 uint8_t *lease_time;
    206 uint32_t lease_time_align = server_config.lease;
    207 struct in_addr addr;
    208
    209 init_packet(&packet, oldpacket, DHCPACK);
    210 packet.yiaddr = yiaddr;
    211
    212 if ((lease_time = get_option(oldpacket, DHCP_LEASE_TIME))) {
    213 memcpy(&lease_time_align, lease_time, 4);
    214 lease_time_align = ntohl(lease_time_align);
    215 if (lease_time_align > server_config.lease)
    216 lease_time_align = server_config.lease;
    217 else if (lease_time_align < server_config.min_lease)
    218 lease_time_align = server_config.lease;
    219 }
    220
    221 add_simple_option(packet.options, DHCP_LEASE_TIME, htonl(lease_time_align));
    222
    223 curr = server_config.options;
    224 while (curr) {
    225 if (curr->data[OPT_CODE] != DHCP_LEASE_TIME)
    226 add_option_string(packet.options, curr->data);
    227 curr = curr->next;
    228 }
    229
    230 add_bootp_options(&packet);
    231
    232 addr.s_addr = packet.yiaddr;
    233 bb_info_msg("Sending ACK to %s", inet_ntoa(addr));
    234
    235 if (send_packet(&packet, 0) < 0)
    236 return -1;
    237
    238 add_lease(packet.chaddr, packet.yiaddr, lease_time_align);
    239
    240 return 0;
    241 }
    242
    243
    244 int send_inform(struct dhcpMessage *oldpacket)
    245 {
    246 struct dhcpMessage packet;
    247 struct option_set *curr;
    248
    249 init_packet(&packet, oldpacket, DHCPACK);
    250
    251 curr = server_config.options;
    252 while (curr) {
    253 if (curr->data[OPT_CODE] != DHCP_LEASE_TIME)
    254 add_option_string(packet.options, curr->data);
    255 curr = curr->next;
    256 }
    257
    258 add_bootp_options(&packet);
    259
    260 return send_packet(&packet, 0);
    261 }