1 /* 2 * CDDL HEADER START 3 * 4 * The contents of this file are subject to the terms of the 5 * Common Development and Distribution License (the "License"). 6 * You may not use this file except in compliance with the License. 7 * 8 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE 9 * or http://www.opensolaris.org/os/licensing. 10 * See the License for the specific language governing permissions 11 * and limitations under the License. 12 * 13 * When distributing Covered Code, include this CDDL HEADER in each 14 * file and include the License file at usr/src/OPENSOLARIS.LICENSE. 15 * If applicable, add the following below this CDDL HEADER, with the 16 * fields enclosed by brackets "[]" replaced with your own identifying 17 * information: Portions Copyright [yyyy] [name of copyright owner] 18 * 19 * CDDL HEADER END 20 */ 21 /* 22 * Copyright 2006 Sun Microsystems, Inc. All rights reserved. 23 * Use is subject to license terms. 24 */ 25 26 #pragma ident "%Z%%M% %I% %E% SMI" 27 28 #include <sys/types.h> 29 #include <time.h> 30 #include <unistd.h> 31 #include <netinet/in.h> 32 #include <netinet/dhcp.h> 33 #include <netinet/udp.h> 34 #include <netinet/ip_var.h> 35 #include <netinet/udp_var.h> 36 #include <libinetutil.h> 37 #include <dhcpmsg.h> 38 #include <string.h> 39 40 #include "packet.h" 41 #include "agent.h" 42 #include "script_handler.h" 43 #include "interface.h" 44 #include "states.h" 45 #include "util.h" 46 47 /* 48 * next_extend_time(): returns the next time an EXTEND request should be sent 49 * 50 * input: monosec_t: the absolute time when the next state is entered 51 * output: uint32_t: the number of seconds in the future to send the next 52 * EXTEND request 53 */ 54 55 static uint32_t 56 next_extend_time(monosec_t limit_monosec) 57 { 58 monosec_t current_monosec = monosec(); 59 60 if (limit_monosec - current_monosec < DHCP_REBIND_MIN) 61 return (0); 62 63 return ((limit_monosec - current_monosec) / 2); 64 } 65 66 /* 67 * dhcp_renew(): attempts to renew a DHCP lease 68 * 69 * input: iu_tq_t *: unused 70 * void *: the ifslist to renew the lease on 71 * output: void 72 */ 73 74 /* ARGSUSED */ 75 void 76 dhcp_renew(iu_tq_t *tqp, void *arg) 77 { 78 struct ifslist *ifsp = (struct ifslist *)arg; 79 uint32_t next; 80 81 82 ifsp->if_timer[DHCP_T1_TIMER] = -1; 83 84 if (check_ifs(ifsp) == 0) { 85 (void) release_ifs(ifsp); 86 return; 87 } 88 89 /* 90 * sanity check: don't send packets if we're past t2. 91 */ 92 93 if (monosec() > (ifsp->if_curstart_monosec + ifsp->if_t2)) 94 return; 95 96 next = next_extend_time(ifsp->if_curstart_monosec + ifsp->if_t2); 97 98 /* 99 * if there isn't an async event pending, then try to renew. 100 */ 101 102 if (!async_pending(ifsp)) 103 if (async_start(ifsp, DHCP_EXTEND, B_FALSE) != 0) 104 105 /* 106 * try to send extend. if we don't succeed, 107 * async_timeout() will clean us up. 108 */ 109 110 (void) dhcp_extending(ifsp); 111 112 /* 113 * if we're within DHCP_REBIND_MIN seconds of REBINDING, don't 114 * reschedule ourselves. 115 */ 116 117 if (next == 0) 118 return; 119 120 /* 121 * no big deal if we can't reschedule; we still have the REBIND 122 * state to save us. 123 */ 124 125 (void) schedule_ifs_timer(ifsp, DHCP_T1_TIMER, next, dhcp_renew); 126 } 127 128 /* 129 * dhcp_rebind(): attempts to renew a DHCP lease from the REBINDING state 130 * 131 * input: iu_tq_t *: unused 132 * void *: the ifslist to renew the lease on 133 * output: void 134 */ 135 136 /* ARGSUSED */ 137 void 138 dhcp_rebind(iu_tq_t *tqp, void *arg) 139 { 140 struct ifslist *ifsp = (struct ifslist *)arg; 141 uint32_t next; 142 143 ifsp->if_timer[DHCP_T2_TIMER] = -1; 144 145 if (check_ifs(ifsp) == 0) { 146 (void) release_ifs(ifsp); 147 return; 148 } 149 150 /* 151 * sanity check: don't send packets if we've already expired. 152 */ 153 154 if (monosec() > (ifsp->if_curstart_monosec + ifsp->if_lease)) 155 return; 156 157 next = next_extend_time(ifsp->if_curstart_monosec + ifsp->if_lease); 158 159 /* 160 * if this is our first venture into the REBINDING state, then 161 * reset the server address. we know the renew timer has 162 * already been cancelled (or we wouldn't be here). 163 */ 164 165 if (ifsp->if_state == RENEWING) { 166 ifsp->if_state = REBINDING; 167 ifsp->if_server.s_addr = htonl(INADDR_BROADCAST); 168 } 169 170 /* 171 * if there isn't an async event pending, then try to rebind. 172 */ 173 174 if (!async_pending(ifsp)) 175 if (async_start(ifsp, DHCP_EXTEND, B_FALSE) != 0) 176 177 /* 178 * try to send extend. if we don't succeed, 179 * async_timeout() will clean us up. 180 */ 181 182 (void) dhcp_extending(ifsp); 183 184 /* 185 * if we're within DHCP_REBIND_MIN seconds of EXPIRE, don't 186 * reschedule ourselves. 187 */ 188 189 if (next == 0) { 190 dhcpmsg(MSG_WARNING, "dhcp_rebind: lease on %s expires in less " 191 "than %i seconds!", ifsp->if_name, DHCP_REBIND_MIN); 192 return; 193 } 194 195 if (schedule_ifs_timer(ifsp, DHCP_T2_TIMER, next, dhcp_rebind) == 0) 196 197 /* 198 * we'll just end up in dhcp_expire(), but it sure sucks. 199 */ 200 201 dhcpmsg(MSG_CRIT, "dhcp_rebind: cannot reschedule another " 202 "rebind attempt; lease may expire for %s", ifsp->if_name); 203 } 204 205 /* 206 * dhcp_restart_lease(): callback function to script_start 207 * 208 * input: struct ifslist *: the interface to be restarted 209 * const char *: unused 210 * output: int: always 1 211 */ 212 213 /* ARGSUSED */ 214 static int 215 dhcp_restart_lease(struct ifslist *ifsp, const char *msg) 216 { 217 dhcpmsg(MSG_INFO, "lease expired on %s -- restarting DHCP", 218 ifsp->if_name); 219 220 /* 221 * in the case where the lease is less than DHCP_REBIND_MIN 222 * seconds, we will never enter dhcp_renew() and thus the packet 223 * counters will not be reset. in that case, reset them here. 224 */ 225 226 if (ifsp->if_state == BOUND) { 227 ifsp->if_bad_offers = 0; 228 ifsp->if_sent = 0; 229 ifsp->if_received = 0; 230 } 231 232 (void) canonize_ifs(ifsp); 233 234 /* reset_ifs() in dhcp_selecting() will clean up any leftover state */ 235 dhcp_selecting(ifsp); 236 return (1); 237 } 238 239 /* 240 * dhcp_expire(): expires a lease on a given interface and restarts DHCP 241 * 242 * input: iu_tq_t *: unused 243 * void *: the ifslist to expire the lease on 244 * output: void 245 */ 246 247 /* ARGSUSED */ 248 void 249 dhcp_expire(iu_tq_t *tqp, void *arg) 250 { 251 struct ifslist *ifsp = (struct ifslist *)arg; 252 253 ifsp->if_timer[DHCP_LEASE_TIMER] = -1; 254 255 if (check_ifs(ifsp) == 0) { 256 (void) release_ifs(ifsp); 257 return; 258 } 259 260 if (async_pending(ifsp)) 261 262 if (async_cancel(ifsp) == 0) { 263 264 dhcpmsg(MSG_WARNING, "dhcp_expire: cannot cancel " 265 "current asynchronous command against %s", 266 ifsp->if_name); 267 268 /* 269 * try to schedule ourselves for callback. 270 * we're really situation critical here 271 * there's not much hope for us if this fails. 272 */ 273 274 if (iu_schedule_timer(tq, DHCP_EXPIRE_WAIT, dhcp_expire, 275 ifsp) != -1) { 276 hold_ifs(ifsp); 277 return; 278 } 279 280 dhcpmsg(MSG_CRIT, "dhcp_expire: cannot reschedule " 281 "dhcp_expire to get called back, proceeding..."); 282 } 283 284 /* 285 * just march on if this fails; at worst someone will be able 286 * to async_start() while we're actually busy with our own 287 * asynchronous transaction. better than not having a lease. 288 */ 289 290 if (async_start(ifsp, DHCP_START, B_FALSE) == 0) 291 dhcpmsg(MSG_WARNING, "dhcp_expire: cannot start asynchronous " 292 "transaction on %s, continuing...", ifsp->if_name); 293 294 (void) script_start(ifsp, EVENT_EXPIRE, dhcp_restart_lease, NULL, NULL); 295 } 296 297 /* 298 * dhcp_extending(): sends a REQUEST to extend a lease on a given interface 299 * and registers to receive the ACK/NAK server reply 300 * 301 * input: struct ifslist *: the interface to send the REQUEST on 302 * output: int: 1 if the extension request was sent, 0 otherwise 303 */ 304 305 int 306 dhcp_extending(struct ifslist *ifsp) 307 { 308 dhcp_pkt_t *dpkt; 309 310 if (ifsp->if_state == BOUND) { 311 ifsp->if_neg_monosec = monosec(); 312 ifsp->if_state = RENEWING; 313 ifsp->if_bad_offers = 0; 314 ifsp->if_sent = 0; 315 ifsp->if_received = 0; 316 } 317 318 dhcpmsg(MSG_DEBUG, "dhcp_extending: registering dhcp_acknak on %s", 319 ifsp->if_name); 320 321 if (register_acknak(ifsp) == 0) { 322 323 ipc_action_finish(ifsp, DHCP_IPC_E_MEMORY); 324 async_finish(ifsp); 325 326 dhcpmsg(MSG_WARNING, "dhcp_extending: cannot register " 327 "dhcp_acknak for %s, not sending renew request", 328 ifsp->if_name); 329 330 return (0); 331 } 332 333 /* 334 * assemble DHCPREQUEST message. The max dhcp message size 335 * option is set to the interface max, minus the size of the udp and 336 * ip headers. 337 */ 338 339 dpkt = init_pkt(ifsp, REQUEST); 340 dpkt->pkt->ciaddr.s_addr = ifsp->if_addr.s_addr; 341 342 add_pkt_opt16(dpkt, CD_MAX_DHCP_SIZE, htons(ifsp->if_max - 343 sizeof (struct udpiphdr))); 344 add_pkt_opt32(dpkt, CD_LEASE_TIME, htonl(DHCP_PERM)); 345 346 add_pkt_opt(dpkt, CD_CLASS_ID, class_id, class_id_len); 347 add_pkt_opt(dpkt, CD_REQUEST_LIST, ifsp->if_prl, ifsp->if_prllen); 348 /* 349 * if_reqhost was set for this interface in dhcp_selecting() 350 * if the REQUEST_HOSTNAME option was set and a host name was 351 * found. 352 */ 353 if (ifsp->if_reqhost != NULL) { 354 add_pkt_opt(dpkt, CD_HOSTNAME, ifsp->if_reqhost, 355 strlen(ifsp->if_reqhost)); 356 } 357 add_pkt_opt(dpkt, CD_END, NULL, 0); 358 359 /* 360 * if we can't send the packet, leave the event handler registered 361 * anyway, since we're not expecting to get any other types of 362 * packets in other than ACKs/NAKs anyway. 363 */ 364 365 return (send_pkt(ifsp, dpkt, ifsp->if_server.s_addr, NULL)); 366 } 367