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dhcp.c

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00001 /**
00002  * @file
00003  * Dynamic Host Configuration Protocol client
00004  *
00005  */
00006 
00007 /*
00008  *
00009  * Copyright (c) 2001-2004 Leon Woestenberg <leon.woestenberg@gmx.net>
00010  * Copyright (c) 2001-2004 Axon Digital Design B.V., The Netherlands.
00011  * All rights reserved.
00012  *
00013  * Redistribution and use in source and binary forms, with or without modification,
00014  * are permitted provided that the following conditions are met:
00015  *
00016  * 1. Redistributions of source code must retain the above copyright notice,
00017  *    this list of conditions and the following disclaimer.
00018  * 2. Redistributions in binary form must reproduce the above copyright notice,
00019  *    this list of conditions and the following disclaimer in the documentation
00020  *    and/or other materials provided with the distribution.
00021  * 3. The name of the author may not be used to endorse or promote products
00022  *    derived from this software without specific prior written permission.
00023  *
00024  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
00025  * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
00026  * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT
00027  * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
00028  * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
00029  * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
00030  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
00031  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
00032  * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
00033  * OF SUCH DAMAGE.
00034  *
00035  * This file is a contribution to the lwIP TCP/IP stack.
00036  * The Swedish Institute of Computer Science and Adam Dunkels
00037  * are specifically granted permission to redistribute this
00038  * source code.
00039  *
00040  * Author: Leon Woestenberg <leon.woestenberg@gmx.net>
00041  *
00042  * This is a DHCP client for the lwIP TCP/IP stack. It aims to conform
00043  * with RFC 2131 and RFC 2132.
00044  *
00045  * TODO:
00046  * - Support for interfaces other than Ethernet (SLIP, PPP, ...)
00047  *
00048  * Please coordinate changes and requests with Leon Woestenberg
00049  * <leon.woestenberg@gmx.net>
00050  *
00051  * Integration with your code:
00052  *
00053  * In lwip/dhcp.h
00054  * #define DHCP_COARSE_TIMER_SECS (recommended 60 which is a minute)
00055  * #define DHCP_FINE_TIMER_MSECS (recommended 500 which equals TCP coarse timer)
00056  *
00057  * Then have your application call dhcp_coarse_tmr() and
00058  * dhcp_fine_tmr() on the defined intervals.
00059  *
00060  * dhcp_start(struct netif *netif);
00061  * starts a DHCP client instance which configures the interface by
00062  * obtaining an IP address lease and maintaining it.
00063  *
00064  * Use dhcp_release(netif) to end the lease and use dhcp_stop(netif)
00065  * to remove the DHCP client.
00066  *
00067  */
00068 
00069 #include "lwip/opt.h"
00070 
00071 #if LWIP_DHCP /* don't build if not configured for use in lwipopts.h */
00072 
00073 #include "lwip/stats.h"
00074 #include "lwip/mem.h"
00075 #include "lwip/udp.h"
00076 #include "lwip/ip_addr.h"
00077 #include "lwip/netif.h"
00078 #include "lwip/def.h"
00079 #include "lwip/sys.h"
00080 #include "lwip/dhcp.h "
00081 #include "lwip/autoip.h"
00082 #include "lwip/dns.h"
00083 #include "netif/etharp.h"
00084 
00085 #include <string.h>
00086 
00087 /** Default for DHCP_GLOBAL_XID is 0xABCD0000
00088  * This can be changed by defining DHCP_GLOBAL_XID and DHCP_GLOBAL_XID_HEADER, e.g.
00089  *  #define DHCP_GLOBAL_XID_HEADER "stdlib.h"
00090  *  #define DHCP_GLOBAL_XID rand()
00091  */
00092 #ifdef DHCP_GLOBAL_XID_HEADER
00093 #include DHCP_GLOBAL_XID_HEADER /* include optional starting XID generation prototypes */
00094 #endif
00095 
00096 /** DHCP_OPTION_MAX_MSG_SIZE is set to the MTU
00097  * MTU is checked to be big enough in dhcp_start */
00098 #define DHCP_MAX_MSG_LEN(netif)        (netif->mtu)
00099 #define DHCP_MAX_MSG_LEN_MIN_REQUIRED  576
00100 /** Minimum length for reply before packet is parsed */
00101 #define DHCP_MIN_REPLY_LEN             44
00102 
00103 #define REBOOT_TRIES 2
00104 
00105 /** Option handling: options are parsed in dhcp_parse_reply
00106  * and saved in an array where other functions can load them from.
00107  * This might be moved into the struct dhcp (not necessarily since
00108  * lwIP is single-threaded and the array is only used while in recv
00109  * callback). */
00110 #define DHCP_OPTION_IDX_OVERLOAD    0
00111 #define DHCP_OPTION_IDX_MSG_TYPE    1
00112 #define DHCP_OPTION_IDX_SERVER_ID   2
00113 #define DHCP_OPTION_IDX_LEASE_TIME  3
00114 #define DHCP_OPTION_IDX_T1          4
00115 #define DHCP_OPTION_IDX_T2          5
00116 #define DHCP_OPTION_IDX_SUBNET_MASK 6
00117 #define DHCP_OPTION_IDX_ROUTER      7
00118 #define DHCP_OPTION_IDX_DNS_SERVER  8
00119 #define DHCP_OPTION_IDX_MAX         (DHCP_OPTION_IDX_DNS_SERVER + DNS_MAX_SERVERS)
00120 
00121 /** Holds the decoded option values, only valid while in dhcp_recv.
00122     @todo: move this into struct dhcp? */
00123 u32_t dhcp_rx_options_val[DHCP_OPTION_IDX_MAX];
00124 /** Holds a flag which option was received and is contained in dhcp_rx_options_val,
00125     only valid while in dhcp_recv.
00126     @todo: move this into struct dhcp? */
00127 u8_t  dhcp_rx_options_given[DHCP_OPTION_IDX_MAX];
00128 
00129 #define dhcp_option_given(dhcp, idx)          (dhcp_rx_options_given[idx] != 0)
00130 #define dhcp_got_option(dhcp, idx)            (dhcp_rx_options_given[idx] = 1)
00131 #define dhcp_clear_option(dhcp, idx)          (dhcp_rx_options_given[idx] = 0)
00132 #define dhcp_clear_all_options(dhcp)          (memset(dhcp_rx_options_given, 0, sizeof(dhcp_rx_options_given)))
00133 #define dhcp_get_option_value(dhcp, idx)      (dhcp_rx_options_val[idx])
00134 #define dhcp_set_option_value(dhcp, idx, val) (dhcp_rx_options_val[idx] = (val))
00135 
00136 
00137 /* DHCP client state machine functions */
00138 static err_t dhcp_discover(struct netif *netif);
00139 static err_t dhcp_select(struct netif *netif);
00140 static void dhcp_bind(struct netif *netif);
00141 #if DHCP_DOES_ARP_CHECK
00142 static err_t dhcp_decline(struct netif *netif);
00143 #endif /* DHCP_DOES_ARP_CHECK */
00144 static err_t dhcp_rebind(struct netif *netif);
00145 static err_t dhcp_reboot(struct netif *netif);
00146 static void dhcp_set_state(struct dhcp *dhcp, u8_t new_state);
00147 
00148 /* receive, unfold, parse and free incoming messages */
00149 static void dhcp_recv(void *arg, struct udp_pcb *pcb, struct pbuf *p, ip_addr_t *addr, u16_t port);
00150 
00151 /* set the DHCP timers */
00152 static void dhcp_timeout(struct netif *netif);
00153 static void dhcp_t1_timeout(struct netif *netif);
00154 static void dhcp_t2_timeout(struct netif *netif);
00155 
00156 /* build outgoing messages */
00157 /* create a DHCP message, fill in common headers */
00158 static err_t dhcp_create_msg(struct netif *netif, struct dhcp *dhcp, u8_t message_type);
00159 /* free a DHCP request */
00160 static void dhcp_delete_msg(struct dhcp *dhcp);
00161 /* add a DHCP option (type, then length in bytes) */
00162 static void dhcp_option(struct dhcp *dhcp, u8_t option_type, u8_t option_len);
00163 /* add option values */
00164 static void dhcp_option_byte(struct dhcp *dhcp, u8_t value);
00165 static void dhcp_option_short(struct dhcp *dhcp, u16_t value);
00166 static void dhcp_option_long(struct dhcp *dhcp, u32_t value);
00167 /* always add the DHCP options trailer to end and pad */
00168 static void dhcp_option_trailer(struct dhcp *dhcp);
00169 
00170 /**
00171  * Back-off the DHCP client (because of a received NAK response).
00172  *
00173  * Back-off the DHCP client because of a received NAK. Receiving a
00174  * NAK means the client asked for something non-sensible, for
00175  * example when it tries to renew a lease obtained on another network.
00176  *
00177  * We clear any existing set IP address and restart DHCP negotiation
00178  * afresh (as per RFC2131 3.2.3).
00179  *
00180  * @param netif the netif under DHCP control
00181  */
00182 static void
00183 dhcp_handle_nak(struct netif *netif)
00184 {
00185   struct dhcp *dhcp = netif->dhcp;
00186   LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE, ("dhcp_handle_nak(netif=%p) %c%c%"U16_F"\n", 
00187     (void*)netif, netif->name[0], netif->name[1], (u16_t)netif->num));
00188   /* Set the interface down since the address must no longer be used, as per RFC2131 */
00189   netif_set_down(netif);
00190   /* remove IP address from interface */
00191   netif_set_ipaddr(netif, IP_ADDR_ANY);
00192   netif_set_gw(netif, IP_ADDR_ANY);
00193   netif_set_netmask(netif, IP_ADDR_ANY); 
00194   /* Change to a defined state */
00195   dhcp_set_state(dhcp, DHCP_BACKING_OFF);
00196   /* We can immediately restart discovery */
00197   dhcp_discover(netif);
00198 }
00199 
00200 #if DHCP_DOES_ARP_CHECK
00201 /**
00202  * Checks if the offered IP address is already in use.
00203  *
00204  * It does so by sending an ARP request for the offered address and
00205  * entering CHECKING state. If no ARP reply is received within a small
00206  * interval, the address is assumed to be free for use by us.
00207  *
00208  * @param netif the netif under DHCP control
00209  */
00210 static void
00211 dhcp_check(struct netif *netif)
00212 {
00213   struct dhcp *dhcp = netif->dhcp;
00214   err_t result;
00215   u16_t msecs;
00216   LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE, ("dhcp_check(netif=%p) %c%c\n", (void *)netif, (s16_t)netif->name[0],
00217     (s16_t)netif->name[1]));
00218   dhcp_set_state(dhcp, DHCP_CHECKING);
00219   /* create an ARP query for the offered IP address, expecting that no host
00220      responds, as the IP address should not be in use. */
00221   result = etharp_query(netif, &dhcp->offered_ip_addr, NULL);
00222   if (result != ERR_OK) {
00223     LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_LEVEL_WARNING, ("dhcp_check: could not perform ARP query\n"));
00224   }
00225   dhcp->tries++;
00226   msecs = 500;
00227   dhcp->request_timeout = (msecs + DHCP_FINE_TIMER_MSECS - 1) / DHCP_FINE_TIMER_MSECS;
00228   LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE, ("dhcp_check(): set request timeout %"U16_F" msecs\n", msecs));
00229 }
00230 #endif /* DHCP_DOES_ARP_CHECK */
00231 
00232 /**
00233  * Remember the configuration offered by a DHCP server.
00234  *
00235  * @param netif the netif under DHCP control
00236  */
00237 static void
00238 dhcp_handle_offer(struct netif *netif)
00239 {
00240   struct dhcp *dhcp = netif->dhcp;
00241   LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE, ("dhcp_handle_offer(netif=%p) %c%c%"U16_F"\n",
00242     (void*)netif, netif->name[0], netif->name[1], (u16_t)netif->num));
00243   /* obtain the server address */
00244   if (dhcp_option_given(dhcp, DHCP_OPTION_IDX_SERVER_ID)) {
00245     ip4_addr_set_u32(&dhcp->server_ip_addr, htonl(dhcp_get_option_value(dhcp, DHCP_OPTION_IDX_SERVER_ID)));
00246     LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_STATE, ("dhcp_handle_offer(): server 0x%08"X32_F"\n",
00247       ip4_addr_get_u32(&dhcp->server_ip_addr)));
00248     /* remember offered address */
00249     ip_addr_copy(dhcp->offered_ip_addr, dhcp->msg_in->yiaddr);
00250     LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_STATE, ("dhcp_handle_offer(): offer for 0x%08"X32_F"\n",
00251       ip4_addr_get_u32(&dhcp->offered_ip_addr)));
00252 
00253     dhcp_select(netif);
00254   } else {
00255     LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_LEVEL_SERIOUS,
00256       ("dhcp_handle_offer(netif=%p) did not get server ID!\n", (void*)netif));
00257   }
00258 }
00259 
00260 /**
00261  * Select a DHCP server offer out of all offers.
00262  *
00263  * Simply select the first offer received.
00264  *
00265  * @param netif the netif under DHCP control
00266  * @return lwIP specific error (see error.h)
00267  */
00268 static err_t
00269 dhcp_select(struct netif *netif)
00270 {
00271   struct dhcp *dhcp = netif->dhcp;
00272   err_t result;
00273   u16_t msecs;
00274 
00275   LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE, ("dhcp_select(netif=%p) %c%c%"U16_F"\n", (void*)netif, netif->name[0], netif->name[1], (u16_t)netif->num));
00276   dhcp_set_state(dhcp, DHCP_REQUESTING);
00277 
00278   /* create and initialize the DHCP message header */
00279   result = dhcp_create_msg(netif, dhcp, DHCP_REQUEST);
00280   if (result == ERR_OK) {
00281     dhcp_option(dhcp, DHCP_OPTION_MAX_MSG_SIZE, DHCP_OPTION_MAX_MSG_SIZE_LEN);
00282     dhcp_option_short(dhcp, DHCP_MAX_MSG_LEN(netif));
00283 
00284     /* MUST request the offered IP address */
00285     dhcp_option(dhcp, DHCP_OPTION_REQUESTED_IP, 4);
00286     dhcp_option_long(dhcp, ntohl(ip4_addr_get_u32(&dhcp->offered_ip_addr)));
00287 
00288     dhcp_option(dhcp, DHCP_OPTION_SERVER_ID, 4);
00289     dhcp_option_long(dhcp, ntohl(ip4_addr_get_u32(&dhcp->server_ip_addr)));
00290 
00291     dhcp_option(dhcp, DHCP_OPTION_PARAMETER_REQUEST_LIST, 4/*num options*/);
00292     dhcp_option_byte(dhcp, DHCP_OPTION_SUBNET_MASK);
00293     dhcp_option_byte(dhcp, DHCP_OPTION_ROUTER);
00294     dhcp_option_byte(dhcp, DHCP_OPTION_BROADCAST);
00295     dhcp_option_byte(dhcp, DHCP_OPTION_DNS_SERVER);
00296 
00297 #if LWIP_NETIF_HOSTNAME
00298     if (netif->hostname != NULL) {
00299       const char *p = (const char*)netif->hostname;
00300       u8_t namelen = (u8_t)strlen(p);
00301       if (namelen > 0) {
00302         LWIP_ASSERT("DHCP: hostname is too long!", namelen < 255);
00303         dhcp_option(dhcp, DHCP_OPTION_HOSTNAME, namelen);
00304         while (*p) {
00305           dhcp_option_byte(dhcp, *p++);
00306         }
00307       }
00308     }
00309 #endif /* LWIP_NETIF_HOSTNAME */
00310 
00311     dhcp_option_trailer(dhcp);
00312     /* shrink the pbuf to the actual content length */
00313     pbuf_realloc(dhcp->p_out, sizeof(struct dhcp_msg) - DHCP_OPTIONS_LEN + dhcp->options_out_len);
00314 
00315     /* send broadcast to any DHCP server */
00316     udp_sendto_if(dhcp->pcb, dhcp->p_out, IP_ADDR_BROADCAST, DHCP_SERVER_PORT, netif);
00317     dhcp_delete_msg(dhcp);
00318     LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE, ("dhcp_select: REQUESTING\n"));
00319   } else {
00320     LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_LEVEL_WARNING, ("dhcp_select: could not allocate DHCP request\n"));
00321   }
00322   dhcp->tries++;
00323   msecs = (dhcp->tries < 6 ? 1 << dhcp->tries : 60) * 1000;
00324   dhcp->request_timeout = (msecs + DHCP_FINE_TIMER_MSECS - 1) / DHCP_FINE_TIMER_MSECS;
00325   LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_STATE, ("dhcp_select(): set request timeout %"U16_F" msecs\n", msecs));
00326   return result;
00327 }
00328 
00329 /**
00330  * The DHCP timer that checks for lease renewal/rebind timeouts.
00331  */
00332 void
00333 dhcp_coarse_tmr()
00334 {
00335   struct netif *netif = netif_list;
00336   LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE, ("dhcp_coarse_tmr()\n"));
00337   /* iterate through all network interfaces */
00338   while (netif != NULL) {
00339     /* only act on DHCP configured interfaces */
00340     if (netif->dhcp != NULL) {
00341       /* timer is active (non zero), and triggers (zeroes) now? */
00342       if (netif->dhcp->t2_timeout-- == 1) {
00343         LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE, ("dhcp_coarse_tmr(): t2 timeout\n"));
00344         /* this clients' rebind timeout triggered */
00345         dhcp_t2_timeout(netif);
00346       /* timer is active (non zero), and triggers (zeroes) now */
00347       } else if (netif->dhcp->t1_timeout-- == 1) {
00348         LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE, ("dhcp_coarse_tmr(): t1 timeout\n"));
00349         /* this clients' renewal timeout triggered */
00350         dhcp_t1_timeout(netif);
00351       }
00352     }
00353     /* proceed to next netif */
00354     netif = netif->next;
00355   }
00356 }
00357 
00358 /**
00359  * DHCP transaction timeout handling
00360  *
00361  * A DHCP server is expected to respond within a short period of time.
00362  * This timer checks whether an outstanding DHCP request is timed out.
00363  */
00364 void
00365 dhcp_fine_tmr()
00366 {
00367   struct netif *netif = netif_list;
00368   /* loop through netif's */
00369   while (netif != NULL) {
00370     /* only act on DHCP configured interfaces */
00371     if (netif->dhcp != NULL) {
00372       /* timer is active (non zero), and is about to trigger now */      
00373       if (netif->dhcp->request_timeout > 1) {
00374         netif->dhcp->request_timeout--;
00375       }
00376       else if (netif->dhcp->request_timeout == 1) {
00377         netif->dhcp->request_timeout--;
00378         /* { netif->dhcp->request_timeout == 0 } */
00379         LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE, ("dhcp_fine_tmr(): request timeout\n"));
00380         /* this client's request timeout triggered */
00381         dhcp_timeout(netif);
00382       }
00383     }
00384     /* proceed to next network interface */
00385     netif = netif->next;
00386   }
00387 }
00388 
00389 /**
00390  * A DHCP negotiation transaction, or ARP request, has timed out.
00391  *
00392  * The timer that was started with the DHCP or ARP request has
00393  * timed out, indicating no response was received in time.
00394  *
00395  * @param netif the netif under DHCP control
00396  */
00397 static void
00398 dhcp_timeout(struct netif *netif)
00399 {
00400   struct dhcp *dhcp = netif->dhcp;
00401   LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE, ("dhcp_timeout()\n"));
00402   /* back-off period has passed, or server selection timed out */
00403   if ((dhcp->state == DHCP_BACKING_OFF) || (dhcp->state == DHCP_SELECTING)) {
00404     LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE, ("dhcp_timeout(): restarting discovery\n"));
00405     dhcp_discover(netif);
00406   /* receiving the requested lease timed out */
00407   } else if (dhcp->state == DHCP_REQUESTING) {
00408     LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE, ("dhcp_timeout(): REQUESTING, DHCP request timed out\n"));
00409     if (dhcp->tries <= 5) {
00410       dhcp_select(netif);
00411     } else {
00412       LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE, ("dhcp_timeout(): REQUESTING, releasing, restarting\n"));
00413       dhcp_release(netif);
00414       dhcp_discover(netif);
00415     }
00416 #if DHCP_DOES_ARP_CHECK
00417   /* received no ARP reply for the offered address (which is good) */
00418   } else if (dhcp->state == DHCP_CHECKING) {
00419     LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE, ("dhcp_timeout(): CHECKING, ARP request timed out\n"));
00420     if (dhcp->tries <= 1) {
00421       dhcp_check(netif);
00422     /* no ARP replies on the offered address,
00423        looks like the IP address is indeed free */
00424     } else {
00425       /* bind the interface to the offered address */
00426       dhcp_bind(netif);
00427     }
00428 #endif /* DHCP_DOES_ARP_CHECK */
00429   }
00430   /* did not get response to renew request? */
00431   else if (dhcp->state == DHCP_RENEWING) {
00432     LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE, ("dhcp_timeout(): RENEWING, DHCP request timed out\n"));
00433     /* just retry renewal */
00434     /* note that the rebind timer will eventually time-out if renew does not work */
00435     dhcp_renew(netif);
00436   /* did not get response to rebind request? */
00437   } else if (dhcp->state == DHCP_REBINDING) {
00438     LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE, ("dhcp_timeout(): REBINDING, DHCP request timed out\n"));
00439     if (dhcp->tries <= 8) {
00440       dhcp_rebind(netif);
00441     } else {
00442       LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE, ("dhcp_timeout(): RELEASING, DISCOVERING\n"));
00443       dhcp_release(netif);
00444       dhcp_discover(netif);
00445     }
00446   } else if (dhcp->state == DHCP_REBOOTING) {
00447     if (dhcp->tries < REBOOT_TRIES) {
00448       dhcp_reboot(netif);
00449     } else {
00450       dhcp_discover(netif);
00451     }
00452   }
00453 }
00454 
00455 /**
00456  * The renewal period has timed out.
00457  *
00458  * @param netif the netif under DHCP control
00459  */
00460 static void
00461 dhcp_t1_timeout(struct netif *netif)
00462 {
00463   struct dhcp *dhcp = netif->dhcp;
00464   LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_STATE, ("dhcp_t1_timeout()\n"));
00465   if ((dhcp->state == DHCP_REQUESTING) || (dhcp->state == DHCP_BOUND) ||
00466       (dhcp->state == DHCP_RENEWING)) {
00467     /* just retry to renew - note that the rebind timer (t2) will
00468      * eventually time-out if renew tries fail. */
00469     LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE,
00470                 ("dhcp_t1_timeout(): must renew\n"));
00471     /* This slightly different to RFC2131: DHCPREQUEST will be sent from state
00472        DHCP_RENEWING, not DHCP_BOUND */
00473     dhcp_renew(netif);
00474   }
00475 }
00476 
00477 /**
00478  * The rebind period has timed out.
00479  *
00480  * @param netif the netif under DHCP control
00481  */
00482 static void
00483 dhcp_t2_timeout(struct netif *netif)
00484 {
00485   struct dhcp *dhcp = netif->dhcp;
00486   LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE, ("dhcp_t2_timeout()\n"));
00487   if ((dhcp->state == DHCP_REQUESTING) || (dhcp->state == DHCP_BOUND) ||
00488       (dhcp->state == DHCP_RENEWING)) {
00489     /* just retry to rebind */
00490     LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE,
00491                 ("dhcp_t2_timeout(): must rebind\n"));
00492     /* This slightly different to RFC2131: DHCPREQUEST will be sent from state
00493        DHCP_REBINDING, not DHCP_BOUND */
00494     dhcp_rebind(netif);
00495   }
00496 }
00497 
00498 /**
00499  * Handle a DHCP ACK packet
00500  *
00501  * @param netif the netif under DHCP control
00502  */
00503 static void
00504 dhcp_handle_ack(struct netif *netif)
00505 {
00506   struct dhcp *dhcp = netif->dhcp;
00507 #if LWIP_DNS
00508   u8_t n;
00509 #endif /* LWIP_DNS */
00510 
00511   /* clear options we might not get from the ACK */
00512   ip_addr_set_zero(&dhcp->offered_sn_mask);
00513   ip_addr_set_zero(&dhcp->offered_gw_addr);
00514 #if LWIP_DHCP_BOOTP_FILE
00515   ip_addr_set_zero(&dhcp->offered_si_addr);
00516 #endif /* LWIP_DHCP_BOOTP_FILE */
00517 
00518   /* lease time given? */
00519   if (dhcp_option_given(dhcp, DHCP_OPTION_IDX_LEASE_TIME)) {
00520     /* remember offered lease time */
00521     dhcp->offered_t0_lease = dhcp_get_option_value(dhcp, DHCP_OPTION_IDX_LEASE_TIME);
00522   }
00523   /* renewal period given? */
00524   if (dhcp_option_given(dhcp, DHCP_OPTION_IDX_T1)) {
00525     /* remember given renewal period */
00526     dhcp->offered_t1_renew = dhcp_get_option_value(dhcp, DHCP_OPTION_IDX_T1);
00527   } else {
00528     /* calculate safe periods for renewal */
00529     dhcp->offered_t1_renew = dhcp->offered_t0_lease / 2;
00530   }
00531 
00532   /* renewal period given? */
00533   if (dhcp_option_given(dhcp, DHCP_OPTION_IDX_T2)) {
00534     /* remember given rebind period */
00535     dhcp->offered_t2_rebind = dhcp_get_option_value(dhcp, DHCP_OPTION_IDX_T2);
00536   } else {
00537     /* calculate safe periods for rebinding */
00538     dhcp->offered_t2_rebind = dhcp->offered_t0_lease;
00539   }
00540 
00541   /* (y)our internet address */
00542   ip_addr_copy(dhcp->offered_ip_addr, dhcp->msg_in->yiaddr);
00543 
00544 #if LWIP_DHCP_BOOTP_FILE
00545   /* copy boot server address,
00546      boot file name copied in dhcp_parse_reply if not overloaded */
00547   ip_addr_copy(dhcp->offered_si_addr, dhcp->msg_in->siaddr);
00548 #endif /* LWIP_DHCP_BOOTP_FILE */
00549 
00550   /* subnet mask given? */
00551   if (dhcp_option_given(dhcp, DHCP_OPTION_IDX_SUBNET_MASK)) {
00552     /* remember given subnet mask */
00553     ip4_addr_set_u32(&dhcp->offered_sn_mask, htonl(dhcp_get_option_value(dhcp, DHCP_OPTION_IDX_SUBNET_MASK)));
00554     dhcp->subnet_mask_given = 1;
00555   } else {
00556     dhcp->subnet_mask_given = 0;
00557   }
00558 
00559   /* gateway router */
00560   if (dhcp_option_given(dhcp, DHCP_OPTION_IDX_ROUTER)) {
00561     ip4_addr_set_u32(&dhcp->offered_gw_addr, htonl(dhcp_get_option_value(dhcp, DHCP_OPTION_IDX_ROUTER)));
00562   }
00563   
00564 #if LWIP_DNS
00565   /* DNS servers */
00566   n = 0;
00567   while(dhcp_option_given(dhcp, DHCP_OPTION_IDX_DNS_SERVER + n) && (n < DNS_MAX_SERVERS)) {
00568     ip_addr_t dns_addr;
00569     ip4_addr_set_u32(&dns_addr, htonl(dhcp_get_option_value(dhcp, DHCP_OPTION_IDX_DNS_SERVER + n)));
00570     dns_setserver(n, &dns_addr);
00571     n++;
00572   }
00573 #endif /* LWIP_DNS */
00574 }
00575 
00576 /** Set a statically allocated struct dhcp to work with.
00577  * Using this prevents dhcp_start to allocate it using mem_malloc.
00578  *
00579  * @param netif the netif for which to set the struct dhcp
00580  * @param dhcp (uninitialised) dhcp struct allocated by the application
00581  */
00582 void
00583 dhcp_set_struct(struct netif *netif, struct dhcp *dhcp)
00584 {
00585   LWIP_ASSERT("netif != NULL", netif != NULL);
00586   LWIP_ASSERT("dhcp != NULL", dhcp != NULL);
00587   LWIP_ASSERT("netif already has a struct dhcp set", netif->dhcp == NULL);
00588 
00589   /* clear data structure */
00590   memset(dhcp, 0, sizeof(struct dhcp));
00591   /* dhcp_set_state(&dhcp, DHCP_OFF); */
00592   netif->dhcp = dhcp;
00593 }
00594 
00595 /** Removes a struct dhcp from a netif.
00596  *
00597  * ATTENTION: Only use this when not using dhcp_set_struct() to allocate the
00598  *            struct dhcp since the memory is passed back to the heap.
00599  *
00600  * @param netif the netif from which to remove the struct dhcp
00601  */
00602 void dhcp_cleanup(struct netif *netif)
00603 {
00604   LWIP_ASSERT("netif != NULL", netif != NULL);
00605 
00606   if (netif->dhcp != NULL) {
00607     mem_free(netif->dhcp);
00608     netif->dhcp = NULL;
00609   }
00610 }
00611 
00612 /**
00613  * Start DHCP negotiation for a network interface.
00614  *
00615  * If no DHCP client instance was attached to this interface,
00616  * a new client is created first. If a DHCP client instance
00617  * was already present, it restarts negotiation.
00618  *
00619  * @param netif The lwIP network interface
00620  * @return lwIP error code
00621  * - ERR_OK - No error
00622  * - ERR_MEM - Out of memory
00623  */
00624 err_t
00625 dhcp_start(struct netif *netif)
00626 {
00627   struct dhcp *dhcp;
00628   err_t result = ERR_OK;
00629 
00630   LWIP_ERROR("netif != NULL", (netif != NULL), return ERR_ARG;);
00631   dhcp = netif->dhcp;
00632   LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE, ("dhcp_start(netif=%p) %c%c%"U16_F"\n", (void*)netif, netif->name[0], netif->name[1], (u16_t)netif->num));
00633   /* Remove the flag that says this netif is handled by DHCP,
00634      it is set when we succeeded starting. */
00635   netif->flags &= ~NETIF_FLAG_DHCP;
00636 
00637   /* check hwtype of the netif */
00638   if ((netif->flags & NETIF_FLAG_ETHARP) == 0) {
00639     LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE, ("dhcp_start(): No ETHARP netif\n"));
00640     return ERR_ARG;
00641   }
00642 
00643   /* check MTU of the netif */
00644   if (netif->mtu < DHCP_MAX_MSG_LEN_MIN_REQUIRED) {
00645     LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE, ("dhcp_start(): Cannot use this netif with DHCP: MTU is too small\n"));
00646     return ERR_MEM;
00647   }
00648 
00649   /* no DHCP client attached yet? */
00650   if (dhcp == NULL) {
00651     LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE, ("dhcp_start(): starting new DHCP client\n"));
00652     dhcp = (struct dhcp *)mem_malloc(sizeof(struct dhcp));
00653     if (dhcp == NULL) {
00654       LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE, ("dhcp_start(): could not allocate dhcp\n"));
00655       return ERR_MEM;
00656     }
00657     /* store this dhcp client in the netif */
00658     netif->dhcp = dhcp;
00659     LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE, ("dhcp_start(): allocated dhcp"));
00660   /* already has DHCP client attached */
00661   } else {
00662     LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE, ("dhcp_start(): restarting DHCP configuration\n"));
00663     if (dhcp->pcb != NULL) {
00664       udp_remove(dhcp->pcb);
00665     }
00666     LWIP_ASSERT("pbuf p_out wasn't freed", dhcp->p_out == NULL);
00667     LWIP_ASSERT("reply wasn't freed", dhcp->msg_in == NULL );
00668   }
00669     
00670   /* clear data structure */
00671   memset(dhcp, 0, sizeof(struct dhcp));
00672   /* dhcp_set_state(&dhcp, DHCP_OFF); */
00673   /* allocate UDP PCB */
00674   dhcp->pcb = udp_new();
00675   if (dhcp->pcb == NULL) {
00676     LWIP_DEBUGF(DHCP_DEBUG  | LWIP_DBG_TRACE, ("dhcp_start(): could not obtain pcb\n"));
00677     return ERR_MEM;
00678   }
00679   dhcp->pcb->so_options |= SOF_BROADCAST;
00680   /* set up local and remote port for the pcb */
00681   udp_bind(dhcp->pcb, IP_ADDR_ANY, DHCP_CLIENT_PORT);
00682   udp_connect(dhcp->pcb, IP_ADDR_ANY, DHCP_SERVER_PORT);
00683   /* set up the recv callback and argument */
00684   udp_recv(dhcp->pcb, dhcp_recv, netif);
00685   LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE, ("dhcp_start(): starting DHCP configuration\n"));
00686   /* (re)start the DHCP negotiation */
00687   result = dhcp_discover(netif);
00688   if (result != ERR_OK) {
00689     /* free resources allocated above */
00690     dhcp_stop(netif);
00691     return ERR_MEM;
00692   }
00693   /* Set the flag that says this netif is handled by DHCP. */
00694   netif->flags |= NETIF_FLAG_DHCP;
00695   return result;
00696 }
00697 
00698 /**
00699  * Inform a DHCP server of our manual configuration.
00700  *
00701  * This informs DHCP servers of our fixed IP address configuration
00702  * by sending an INFORM message. It does not involve DHCP address
00703  * configuration, it is just here to be nice to the network.
00704  *
00705  * @param netif The lwIP network interface
00706  */
00707 void
00708 dhcp_inform(struct netif *netif)
00709 {
00710   struct dhcp dhcp;
00711   err_t result = ERR_OK;
00712   struct udp_pcb *pcb;
00713 
00714   LWIP_ERROR("netif != NULL", (netif != NULL), return;);
00715 
00716   memset(&dhcp, 0, sizeof(struct dhcp));
00717   dhcp_set_state(&dhcp, DHCP_INFORM);
00718 
00719   if ((netif->dhcp != NULL) && (netif->dhcp->pcb != NULL)) {
00720     /* re-use existing pcb */
00721     pcb = netif->dhcp->pcb;
00722   } else {
00723     pcb = udp_new();
00724     if (pcb == NULL) {
00725       LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_LEVEL_SERIOUS, ("dhcp_inform(): could not obtain pcb"));
00726       return;
00727     }
00728     dhcp.pcb = pcb;
00729     dhcp.pcb->so_options |= SOF_BROADCAST;
00730     udp_bind(dhcp.pcb, IP_ADDR_ANY, DHCP_CLIENT_PORT);
00731     LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE, ("dhcp_inform(): created new udp pcb\n"));
00732   }
00733   /* create and initialize the DHCP message header */
00734   result = dhcp_create_msg(netif, &dhcp, DHCP_INFORM);
00735   if (result == ERR_OK) {
00736     dhcp_option(&dhcp, DHCP_OPTION_MAX_MSG_SIZE, DHCP_OPTION_MAX_MSG_SIZE_LEN);
00737     dhcp_option_short(&dhcp, DHCP_MAX_MSG_LEN(netif));
00738 
00739     dhcp_option_trailer(&dhcp);
00740 
00741     pbuf_realloc(dhcp.p_out, sizeof(struct dhcp_msg) - DHCP_OPTIONS_LEN + dhcp.options_out_len);
00742 
00743     LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE, ("dhcp_inform: INFORMING\n"));
00744     udp_sendto_if(pcb, dhcp.p_out, IP_ADDR_BROADCAST, DHCP_SERVER_PORT, netif);
00745     dhcp_delete_msg(&dhcp);
00746   } else {
00747     LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_LEVEL_SERIOUS, ("dhcp_inform: could not allocate DHCP request\n"));
00748   }
00749 
00750   if (dhcp.pcb != NULL) {
00751     /* otherwise, the existing pcb was used */
00752     udp_remove(dhcp.pcb);
00753   }
00754 }
00755 
00756 /** Handle a possible change in the network configuration.
00757  *
00758  * This enters the REBOOTING state to verify that the currently bound
00759  * address is still valid.
00760  */
00761 void
00762 dhcp_network_changed(struct netif *netif)
00763 {
00764   struct dhcp *dhcp = netif->dhcp;
00765   if (!dhcp)
00766     return;
00767   switch (dhcp->state) {
00768   case DHCP_REBINDING:
00769   case DHCP_RENEWING:
00770   case DHCP_BOUND:
00771   case DHCP_REBOOTING:
00772     netif_set_down(netif);
00773     dhcp->tries = 0;
00774     dhcp_reboot(netif);
00775     break;
00776   case DHCP_OFF:
00777     /* stay off */
00778     break;
00779   default:
00780     dhcp->tries = 0;
00781 #if LWIP_DHCP_AUTOIP_COOP
00782     if(dhcp->autoip_coop_state == DHCP_AUTOIP_COOP_STATE_ON) {
00783       autoip_stop(netif);
00784       dhcp->autoip_coop_state = DHCP_AUTOIP_COOP_STATE_OFF;
00785     }
00786 #endif /* LWIP_DHCP_AUTOIP_COOP */
00787     dhcp_discover(netif);
00788     break;
00789   }
00790 }
00791 
00792 #if DHCP_DOES_ARP_CHECK
00793 /**
00794  * Match an ARP reply with the offered IP address.
00795  *
00796  * @param netif the network interface on which the reply was received
00797  * @param addr The IP address we received a reply from
00798  */
00799 void dhcp_arp_reply(struct netif *netif, ip_addr_t *addr)
00800 {
00801   LWIP_ERROR("netif != NULL", (netif != NULL), return;);
00802   LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE, ("dhcp_arp_reply()\n"));
00803   /* is a DHCP client doing an ARP check? */
00804   if ((netif->dhcp != NULL) && (netif->dhcp->state == DHCP_CHECKING)) {
00805     LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE, ("dhcp_arp_reply(): CHECKING, arp reply for 0x%08"X32_F"\n",
00806       ip4_addr_get_u32(addr)));
00807     /* did a host respond with the address we
00808        were offered by the DHCP server? */
00809     if (ip_addr_cmp(addr, &netif->dhcp->offered_ip_addr)) {
00810       /* we will not accept the offered address */
00811       LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE | LWIP_DBG_LEVEL_WARNING,
00812         ("dhcp_arp_reply(): arp reply matched with offered address, declining\n"));
00813       dhcp_decline(netif);
00814     }
00815   }
00816 }
00817 
00818 /**
00819  * Decline an offered lease.
00820  *
00821  * Tell the DHCP server we do not accept the offered address.
00822  * One reason to decline the lease is when we find out the address
00823  * is already in use by another host (through ARP).
00824  *
00825  * @param netif the netif under DHCP control
00826  */
00827 static err_t
00828 dhcp_decline(struct netif *netif)
00829 {
00830   struct dhcp *dhcp = netif->dhcp;
00831   err_t result = ERR_OK;
00832   u16_t msecs;
00833   LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE, ("dhcp_decline()\n"));
00834   dhcp_set_state(dhcp, DHCP_BACKING_OFF);
00835   /* create and initialize the DHCP message header */
00836   result = dhcp_create_msg(netif, dhcp, DHCP_DECLINE);
00837   if (result == ERR_OK) {
00838     dhcp_option(dhcp, DHCP_OPTION_REQUESTED_IP, 4);
00839     dhcp_option_long(dhcp, ntohl(ip4_addr_get_u32(&dhcp->offered_ip_addr)));
00840 
00841     dhcp_option_trailer(dhcp);
00842     /* resize pbuf to reflect true size of options */
00843     pbuf_realloc(dhcp->p_out, sizeof(struct dhcp_msg) - DHCP_OPTIONS_LEN + dhcp->options_out_len);
00844 
00845     /* per section 4.4.4, broadcast DECLINE messages */
00846     udp_sendto_if(dhcp->pcb, dhcp->p_out, IP_ADDR_BROADCAST, DHCP_SERVER_PORT, netif);
00847     dhcp_delete_msg(dhcp);
00848     LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE, ("dhcp_decline: BACKING OFF\n"));
00849   } else {
00850     LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_LEVEL_SERIOUS,
00851       ("dhcp_decline: could not allocate DHCP request\n"));
00852   }
00853   dhcp->tries++;
00854   msecs = 10*1000;
00855   dhcp->request_timeout = (msecs + DHCP_FINE_TIMER_MSECS - 1) / DHCP_FINE_TIMER_MSECS;
00856   LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE, ("dhcp_decline(): set request timeout %"U16_F" msecs\n", msecs));
00857   return result;
00858 }
00859 #endif /* DHCP_DOES_ARP_CHECK */
00860 
00861 
00862 /**
00863  * Start the DHCP process, discover a DHCP server.
00864  *
00865  * @param netif the netif under DHCP control
00866  */
00867 static err_t
00868 dhcp_discover(struct netif *netif)
00869 {
00870   struct dhcp *dhcp = netif->dhcp;
00871   err_t result = ERR_OK;
00872   u16_t msecs;
00873   LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE, ("dhcp_discover()\n"));
00874   ip_addr_set_any(&dhcp->offered_ip_addr);
00875   dhcp_set_state(dhcp, DHCP_SELECTING);
00876   /* create and initialize the DHCP message header */
00877   result = dhcp_create_msg(netif, dhcp, DHCP_DISCOVER);
00878   if (result == ERR_OK) {
00879     LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE, ("dhcp_discover: making request\n"));
00880 
00881     dhcp_option(dhcp, DHCP_OPTION_MAX_MSG_SIZE, DHCP_OPTION_MAX_MSG_SIZE_LEN);
00882     dhcp_option_short(dhcp, DHCP_MAX_MSG_LEN(netif));
00883 
00884     dhcp_option(dhcp, DHCP_OPTION_PARAMETER_REQUEST_LIST, 4/*num options*/);
00885     dhcp_option_byte(dhcp, DHCP_OPTION_SUBNET_MASK);
00886     dhcp_option_byte(dhcp, DHCP_OPTION_ROUTER);
00887     dhcp_option_byte(dhcp, DHCP_OPTION_BROADCAST);
00888     dhcp_option_byte(dhcp, DHCP_OPTION_DNS_SERVER);
00889 
00890     dhcp_option_trailer(dhcp);
00891 
00892     LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE, ("dhcp_discover: realloc()ing\n"));
00893     pbuf_realloc(dhcp->p_out, sizeof(struct dhcp_msg) - DHCP_OPTIONS_LEN + dhcp->options_out_len);
00894 
00895     LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE, ("dhcp_discover: sendto(DISCOVER, IP_ADDR_BROADCAST, DHCP_SERVER_PORT)\n"));
00896     udp_sendto_if(dhcp->pcb, dhcp->p_out, IP_ADDR_BROADCAST, DHCP_SERVER_PORT, netif);
00897     LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE, ("dhcp_discover: deleting()ing\n"));
00898     dhcp_delete_msg(dhcp);
00899     LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE, ("dhcp_discover: SELECTING\n"));
00900   } else {
00901     LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_LEVEL_SERIOUS, ("dhcp_discover: could not allocate DHCP request\n"));
00902   }
00903   dhcp->tries++;
00904 #if LWIP_DHCP_AUTOIP_COOP
00905   if(dhcp->tries >= LWIP_DHCP_AUTOIP_COOP_TRIES && dhcp->autoip_coop_state == DHCP_AUTOIP_COOP_STATE_OFF) {
00906     dhcp->autoip_coop_state = DHCP_AUTOIP_COOP_STATE_ON;
00907     autoip_start(netif);
00908   }
00909 #endif /* LWIP_DHCP_AUTOIP_COOP */
00910   msecs = (dhcp->tries < 6 ? 1 << dhcp->tries : 60) * 1000;
00911   dhcp->request_timeout = (msecs + DHCP_FINE_TIMER_MSECS - 1) / DHCP_FINE_TIMER_MSECS;
00912   LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE, ("dhcp_discover(): set request timeout %"U16_F" msecs\n", msecs));
00913   return result;
00914 }
00915 
00916 
00917 /**
00918  * Bind the interface to the offered IP address.
00919  *
00920  * @param netif network interface to bind to the offered address
00921  */
00922 static void
00923 dhcp_bind(struct netif *netif)
00924 {
00925   u32_t timeout;
00926   struct dhcp *dhcp;
00927   ip_addr_t sn_mask, gw_addr;
00928   LWIP_ERROR("dhcp_bind: netif != NULL", (netif != NULL), return;);
00929   dhcp = netif->dhcp;
00930   LWIP_ERROR("dhcp_bind: dhcp != NULL", (dhcp != NULL), return;);
00931   LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE, ("dhcp_bind(netif=%p) %c%c%"U16_F"\n", (void*)netif, netif->name[0], netif->name[1], (u16_t)netif->num));
00932 
00933   /* temporary DHCP lease? */
00934   if (dhcp->offered_t1_renew != 0xffffffffUL) {
00935     /* set renewal period timer */
00936     LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE, ("dhcp_bind(): t1 renewal timer %"U32_F" secs\n", dhcp->offered_t1_renew));
00937     timeout = (dhcp->offered_t1_renew + DHCP_COARSE_TIMER_SECS / 2) / DHCP_COARSE_TIMER_SECS;
00938     if(timeout > 0xffff) {
00939       timeout = 0xffff;
00940     }
00941     dhcp->t1_timeout = (u16_t)timeout;
00942     if (dhcp->t1_timeout == 0) {
00943       dhcp->t1_timeout = 1;
00944     }
00945     LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE, ("dhcp_bind(): set request timeout %"U32_F" msecs\n", dhcp->offered_t1_renew*1000));
00946   }
00947   /* set renewal period timer */
00948   if (dhcp->offered_t2_rebind != 0xffffffffUL) {
00949     LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE, ("dhcp_bind(): t2 rebind timer %"U32_F" secs\n", dhcp->offered_t2_rebind));
00950     timeout = (dhcp->offered_t2_rebind + DHCP_COARSE_TIMER_SECS / 2) / DHCP_COARSE_TIMER_SECS;
00951     if(timeout > 0xffff) {
00952       timeout = 0xffff;
00953     }
00954     dhcp->t2_timeout = (u16_t)timeout;
00955     if (dhcp->t2_timeout == 0) {
00956       dhcp->t2_timeout = 1;
00957     }
00958     LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE, ("dhcp_bind(): set request timeout %"U32_F" msecs\n", dhcp->offered_t2_rebind*1000));
00959   }
00960 
00961   if (dhcp->subnet_mask_given) {
00962     /* copy offered network mask */
00963     ip_addr_copy(sn_mask, dhcp->offered_sn_mask);
00964   } else {
00965     /* subnet mask not given, choose a safe subnet mask given the network class */
00966     u8_t first_octet = ip4_addr1(&dhcp->offered_ip_addr);
00967     if (first_octet <= 127) {
00968       ip4_addr_set_u32(&sn_mask, PP_HTONL(0xff000000UL));
00969     } else if (first_octet >= 192) {
00970       ip4_addr_set_u32(&sn_mask, PP_HTONL(0xffffff00UL));
00971     } else {
00972       ip4_addr_set_u32(&sn_mask, PP_HTONL(0xffff0000UL));
00973     }
00974   }
00975 
00976   ip_addr_copy(gw_addr, dhcp->offered_gw_addr);
00977   /* gateway address not given? */
00978   if (ip_addr_isany(&gw_addr)) {
00979     /* copy network address */
00980     ip_addr_get_network(&gw_addr, &dhcp->offered_ip_addr, &sn_mask);
00981     /* use first host address on network as gateway */
00982     ip4_addr_set_u32(&gw_addr, ip4_addr_get_u32(&gw_addr) | PP_HTONL(0x00000001UL));
00983   }
00984 
00985 #if LWIP_DHCP_AUTOIP_COOP
00986   if(dhcp->autoip_coop_state == DHCP_AUTOIP_COOP_STATE_ON) {
00987     autoip_stop(netif);
00988     dhcp->autoip_coop_state = DHCP_AUTOIP_COOP_STATE_OFF;
00989   }
00990 #endif /* LWIP_DHCP_AUTOIP_COOP */
00991 
00992   LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_STATE, ("dhcp_bind(): IP: %d.%d.%d.%d\n",
00993     ip4_addr1(&dhcp->offered_ip_addr), ip4_addr2(&dhcp->offered_ip_addr), ip4_addr3(&dhcp->offered_ip_addr), ip4_addr4(&dhcp->offered_ip_addr)));
00994   netif_set_ipaddr(netif, &dhcp->offered_ip_addr);
00995   LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_STATE, ("dhcp_bind(): SN: 0x%08"X32_F"\n",
00996     ip4_addr_get_u32(&sn_mask)));
00997   netif_set_netmask(netif, &sn_mask);
00998   LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_STATE, ("dhcp_bind(): GW: 0x%08"X32_F"\n",
00999     ip4_addr_get_u32(&gw_addr)));
01000   netif_set_gw(netif, &gw_addr);
01001   /* bring the interface up */
01002   netif_set_up(netif);
01003   /* netif is now bound to DHCP leased address */
01004   dhcp_set_state(dhcp, DHCP_BOUND);
01005 }
01006 
01007 /**
01008  * Renew an existing DHCP lease at the involved DHCP server.
01009  *
01010  * @param netif network interface which must renew its lease
01011  */
01012 err_t
01013 dhcp_renew(struct netif *netif)
01014 {
01015   struct dhcp *dhcp = netif->dhcp;
01016   err_t result;
01017   u16_t msecs;
01018   LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE, ("dhcp_renew()\n"));
01019   dhcp_set_state(dhcp, DHCP_RENEWING);
01020 
01021   /* create and initialize the DHCP message header */
01022   result = dhcp_create_msg(netif, dhcp, DHCP_REQUEST);
01023   if (result == ERR_OK) {
01024     dhcp_option(dhcp, DHCP_OPTION_MAX_MSG_SIZE, DHCP_OPTION_MAX_MSG_SIZE_LEN);
01025     dhcp_option_short(dhcp, DHCP_MAX_MSG_LEN(netif));
01026 
01027 #if LWIP_NETIF_HOSTNAME
01028     if (netif->hostname != NULL) {
01029       const char *p = (const char*)netif->hostname;
01030       u8_t namelen = (u8_t)strlen(p);
01031       if (namelen > 0) {
01032         LWIP_ASSERT("DHCP: hostname is too long!", namelen < 255);
01033         dhcp_option(dhcp, DHCP_OPTION_HOSTNAME, namelen);
01034         while (*p) {
01035           dhcp_option_byte(dhcp, *p++);
01036         }
01037       }
01038     }
01039 #endif /* LWIP_NETIF_HOSTNAME */
01040 
01041 #if 0
01042     dhcp_option(dhcp, DHCP_OPTION_REQUESTED_IP, 4);
01043     dhcp_option_long(dhcp, ntohl(dhcp->offered_ip_addr.addr));
01044 #endif
01045 
01046 #if 0
01047     dhcp_option(dhcp, DHCP_OPTION_SERVER_ID, 4);
01048     dhcp_option_long(dhcp, ntohl(dhcp->server_ip_addr.addr));
01049 #endif
01050     /* append DHCP message trailer */
01051     dhcp_option_trailer(dhcp);
01052 
01053     pbuf_realloc(dhcp->p_out, sizeof(struct dhcp_msg) - DHCP_OPTIONS_LEN + dhcp->options_out_len);
01054 
01055     udp_sendto_if(dhcp->pcb, dhcp->p_out, &dhcp->server_ip_addr, DHCP_SERVER_PORT, netif);
01056     dhcp_delete_msg(dhcp);
01057 
01058     LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE, ("dhcp_renew: RENEWING\n"));
01059   } else {
01060     LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_LEVEL_SERIOUS, ("dhcp_renew: could not allocate DHCP request\n"));
01061   }
01062   dhcp->tries++;
01063   /* back-off on retries, but to a maximum of 20 seconds */
01064   msecs = dhcp->tries < 10 ? dhcp->tries * 2000 : 20 * 1000;
01065   dhcp->request_timeout = (msecs + DHCP_FINE_TIMER_MSECS - 1) / DHCP_FINE_TIMER_MSECS;
01066   LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE, ("dhcp_renew(): set request timeout %"U16_F" msecs\n", msecs));
01067   return result;
01068 }
01069 
01070 /**
01071  * Rebind with a DHCP server for an existing DHCP lease.
01072  *
01073  * @param netif network interface which must rebind with a DHCP server
01074  */
01075 static err_t
01076 dhcp_rebind(struct netif *netif)
01077 {
01078   struct dhcp *dhcp = netif->dhcp;
01079   err_t result;
01080   u16_t msecs;
01081   LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE, ("dhcp_rebind()\n"));
01082   dhcp_set_state(dhcp, DHCP_REBINDING);
01083 
01084   /* create and initialize the DHCP message header */
01085   result = dhcp_create_msg(netif, dhcp, DHCP_REQUEST);
01086   if (result == ERR_OK) {
01087     dhcp_option(dhcp, DHCP_OPTION_MAX_MSG_SIZE, DHCP_OPTION_MAX_MSG_SIZE_LEN);
01088     dhcp_option_short(dhcp, DHCP_MAX_MSG_LEN(netif));
01089 
01090 #if LWIP_NETIF_HOSTNAME
01091     if (netif->hostname != NULL) {
01092       const char *p = (const char*)netif->hostname;
01093       u8_t namelen = (u8_t)strlen(p);
01094       if (namelen > 0) {
01095         LWIP_ASSERT("DHCP: hostname is too long!", namelen < 255);
01096         dhcp_option(dhcp, DHCP_OPTION_HOSTNAME, namelen);
01097         while (*p) {
01098           dhcp_option_byte(dhcp, *p++);
01099         }
01100       }
01101     }
01102 #endif /* LWIP_NETIF_HOSTNAME */
01103 
01104 #if 0
01105     dhcp_option(dhcp, DHCP_OPTION_REQUESTED_IP, 4);
01106     dhcp_option_long(dhcp, ntohl(dhcp->offered_ip_addr.addr));
01107 
01108     dhcp_option(dhcp, DHCP_OPTION_SERVER_ID, 4);
01109     dhcp_option_long(dhcp, ntohl(dhcp->server_ip_addr.addr));
01110 #endif
01111 
01112     dhcp_option_trailer(dhcp);
01113 
01114     pbuf_realloc(dhcp->p_out, sizeof(struct dhcp_msg) - DHCP_OPTIONS_LEN + dhcp->options_out_len);
01115 
01116     /* broadcast to server */
01117     udp_sendto_if(dhcp->pcb, dhcp->p_out, IP_ADDR_BROADCAST, DHCP_SERVER_PORT, netif);
01118     dhcp_delete_msg(dhcp);
01119     LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE, ("dhcp_rebind: REBINDING\n"));
01120   } else {
01121     LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_LEVEL_SERIOUS, ("dhcp_rebind: could not allocate DHCP request\n"));
01122   }
01123   dhcp->tries++;
01124   msecs = dhcp->tries < 10 ? dhcp->tries * 1000 : 10 * 1000;
01125   dhcp->request_timeout = (msecs + DHCP_FINE_TIMER_MSECS - 1) / DHCP_FINE_TIMER_MSECS;
01126   LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE, ("dhcp_rebind(): set request timeout %"U16_F" msecs\n", msecs));
01127   return result;
01128 }
01129 
01130 /**
01131  * Enter REBOOTING state to verify an existing lease
01132  *
01133  * @param netif network interface which must reboot
01134  */
01135 static err_t
01136 dhcp_reboot(struct netif *netif)
01137 {
01138   struct dhcp *dhcp = netif->dhcp;
01139   err_t result;
01140   u16_t msecs;
01141   LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE, ("dhcp_reboot()\n"));
01142   dhcp_set_state(dhcp, DHCP_REBOOTING);
01143 
01144   /* create and initialize the DHCP message header */
01145   result = dhcp_create_msg(netif, dhcp, DHCP_REQUEST);
01146   if (result == ERR_OK) {
01147     dhcp_option(dhcp, DHCP_OPTION_MAX_MSG_SIZE, DHCP_OPTION_MAX_MSG_SIZE_LEN);
01148     dhcp_option_short(dhcp, 576);
01149 
01150     dhcp_option(dhcp, DHCP_OPTION_REQUESTED_IP, 4);
01151     dhcp_option_long(dhcp, ntohl(ip4_addr_get_u32(&dhcp->offered_ip_addr)));
01152 
01153     dhcp_option_trailer(dhcp);
01154 
01155     pbuf_realloc(dhcp->p_out, sizeof(struct dhcp_msg) - DHCP_OPTIONS_LEN + dhcp->options_out_len);
01156 
01157     /* broadcast to server */
01158     udp_sendto_if(dhcp->pcb, dhcp->p_out, IP_ADDR_BROADCAST, DHCP_SERVER_PORT, netif);
01159     dhcp_delete_msg(dhcp);
01160     LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE, ("dhcp_reboot: REBOOTING\n"));
01161   } else {
01162     LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_LEVEL_SERIOUS, ("dhcp_reboot: could not allocate DHCP request\n"));
01163   }
01164   dhcp->tries++;
01165   msecs = dhcp->tries < 10 ? dhcp->tries * 1000 : 10 * 1000;
01166   dhcp->request_timeout = (msecs + DHCP_FINE_TIMER_MSECS - 1) / DHCP_FINE_TIMER_MSECS;
01167   LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE, ("dhcp_reboot(): set request timeout %"U16_F" msecs\n", msecs));
01168   return result;
01169 }
01170 
01171 
01172 /**
01173  * Release a DHCP lease.
01174  *
01175  * @param netif network interface which must release its lease
01176  */
01177 err_t
01178 dhcp_release(struct netif *netif)
01179 {
01180   struct dhcp *dhcp = netif->dhcp;
01181   err_t result;
01182   u16_t msecs;
01183   LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE, ("dhcp_release()\n"));
01184 
01185   /* idle DHCP client */
01186   dhcp_set_state(dhcp, DHCP_OFF);
01187   /* clean old DHCP offer */
01188   ip_addr_set_zero(&dhcp->server_ip_addr);
01189   ip_addr_set_zero(&dhcp->offered_ip_addr);
01190   ip_addr_set_zero(&dhcp->offered_sn_mask);
01191   ip_addr_set_zero(&dhcp->offered_gw_addr);
01192 #if LWIP_DHCP_BOOTP_FILE
01193   ip_addr_set_zero(&dhcp->offered_si_addr);
01194 #endif /* LWIP_DHCP_BOOTP_FILE */
01195   dhcp->offered_t0_lease = dhcp->offered_t1_renew = dhcp->offered_t2_rebind = 0;
01196   
01197   /* create and initialize the DHCP message header */
01198   result = dhcp_create_msg(netif, dhcp, DHCP_RELEASE);
01199   if (result == ERR_OK) {
01200     dhcp_option_trailer(dhcp);
01201 
01202     pbuf_realloc(dhcp->p_out, sizeof(struct dhcp_msg) - DHCP_OPTIONS_LEN + dhcp->options_out_len);
01203 
01204     udp_sendto_if(dhcp->pcb, dhcp->p_out, &dhcp->server_ip_addr, DHCP_SERVER_PORT, netif);
01205     dhcp_delete_msg(dhcp);
01206     LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE, ("dhcp_release: RELEASED, DHCP_OFF\n"));
01207   } else {
01208     LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_LEVEL_SERIOUS, ("dhcp_release: could not allocate DHCP request\n"));
01209   }
01210   dhcp->tries++;
01211   msecs = dhcp->tries < 10 ? dhcp->tries * 1000 : 10 * 1000;
01212   dhcp->request_timeout = (msecs + DHCP_FINE_TIMER_MSECS - 1) / DHCP_FINE_TIMER_MSECS;
01213   LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE, ("dhcp_release(): set request timeout %"U16_F" msecs\n", msecs));
01214   /* bring the interface down */
01215   netif_set_down(netif);
01216   /* remove IP address from interface */
01217   netif_set_ipaddr(netif, IP_ADDR_ANY);
01218   netif_set_gw(netif, IP_ADDR_ANY);
01219   netif_set_netmask(netif, IP_ADDR_ANY);
01220   
01221   return result;
01222 }
01223 
01224 /**
01225  * Remove the DHCP client from the interface.
01226  *
01227  * @param netif The network interface to stop DHCP on
01228  */
01229 void
01230 dhcp_stop(struct netif *netif)
01231 {
01232   struct dhcp *dhcp;
01233   LWIP_ERROR("dhcp_stop: netif != NULL", (netif != NULL), return;);
01234   dhcp = netif->dhcp;
01235   /* Remove the flag that says this netif is handled by DHCP. */
01236   netif->flags &= ~NETIF_FLAG_DHCP;
01237 
01238   LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE, ("dhcp_stop()\n"));
01239   /* netif is DHCP configured? */
01240   if (dhcp != NULL) {
01241 #if LWIP_DHCP_AUTOIP_COOP
01242     if(dhcp->autoip_coop_state == DHCP_AUTOIP_COOP_STATE_ON) {
01243       autoip_stop(netif);
01244       dhcp->autoip_coop_state = DHCP_AUTOIP_COOP_STATE_OFF;
01245     }
01246 #endif /* LWIP_DHCP_AUTOIP_COOP */
01247 
01248     if (dhcp->pcb != NULL) {
01249       udp_remove(dhcp->pcb);
01250       dhcp->pcb = NULL;
01251     }
01252     LWIP_ASSERT("reply wasn't freed", dhcp->msg_in == NULL);
01253     dhcp_set_state(dhcp, DHCP_OFF);
01254   }
01255 }
01256 
01257 /*
01258  * Set the DHCP state of a DHCP client.
01259  *
01260  * If the state changed, reset the number of tries.
01261  */
01262 static void
01263 dhcp_set_state(struct dhcp *dhcp, u8_t new_state)
01264 {
01265   if (new_state != dhcp->state) {
01266     dhcp->state = new_state;
01267     dhcp->tries = 0;
01268     dhcp->request_timeout = 0;
01269   }
01270 }
01271 
01272 /*
01273  * Concatenate an option type and length field to the outgoing
01274  * DHCP message.
01275  *
01276  */
01277 static void
01278 dhcp_option(struct dhcp *dhcp, u8_t option_type, u8_t option_len)
01279 {
01280   LWIP_ASSERT("dhcp_option: dhcp->options_out_len + 2 + option_len <= DHCP_OPTIONS_LEN", dhcp->options_out_len + 2U + option_len <= DHCP_OPTIONS_LEN);
01281   dhcp->msg_out->options[dhcp->options_out_len++] = option_type;
01282   dhcp->msg_out->options[dhcp->options_out_len++] = option_len;
01283 }
01284 /*
01285  * Concatenate a single byte to the outgoing DHCP message.
01286  *
01287  */
01288 static void
01289 dhcp_option_byte(struct dhcp *dhcp, u8_t value)
01290 {
01291   LWIP_ASSERT("dhcp_option_byte: dhcp->options_out_len < DHCP_OPTIONS_LEN", dhcp->options_out_len < DHCP_OPTIONS_LEN);
01292   dhcp->msg_out->options[dhcp->options_out_len++] = value;
01293 }
01294 
01295 static void
01296 dhcp_option_short(struct dhcp *dhcp, u16_t value)
01297 {
01298   LWIP_ASSERT("dhcp_option_short: dhcp->options_out_len + 2 <= DHCP_OPTIONS_LEN", dhcp->options_out_len + 2U <= DHCP_OPTIONS_LEN);
01299   dhcp->msg_out->options[dhcp->options_out_len++] = (u8_t)((value & 0xff00U) >> 8);
01300   dhcp->msg_out->options[dhcp->options_out_len++] = (u8_t) (value & 0x00ffU);
01301 }
01302 
01303 static void
01304 dhcp_option_long(struct dhcp *dhcp, u32_t value)
01305 {
01306   LWIP_ASSERT("dhcp_option_long: dhcp->options_out_len + 4 <= DHCP_OPTIONS_LEN", dhcp->options_out_len + 4U <= DHCP_OPTIONS_LEN);
01307   dhcp->msg_out->options[dhcp->options_out_len++] = (u8_t)((value & 0xff000000UL) >> 24);
01308   dhcp->msg_out->options[dhcp->options_out_len++] = (u8_t)((value & 0x00ff0000UL) >> 16);
01309   dhcp->msg_out->options[dhcp->options_out_len++] = (u8_t)((value & 0x0000ff00UL) >> 8);
01310   dhcp->msg_out->options[dhcp->options_out_len++] = (u8_t)((value & 0x000000ffUL));
01311 }
01312 
01313 /**
01314  * Extract the DHCP message and the DHCP options.
01315  *
01316  * Extract the DHCP message and the DHCP options, each into a contiguous
01317  * piece of memory. As a DHCP message is variable sized by its options,
01318  * and also allows overriding some fields for options, the easy approach
01319  * is to first unfold the options into a conitguous piece of memory, and
01320  * use that further on.
01321  *
01322  */
01323 static err_t
01324 dhcp_parse_reply(struct dhcp *dhcp, struct pbuf *p)
01325 {
01326   u8_t *options;
01327   u16_t offset;
01328   u16_t offset_max;
01329   u16_t options_idx;
01330   u16_t options_idx_max;
01331   struct pbuf *q;
01332   int parse_file_as_options = 0;
01333   int parse_sname_as_options = 0;
01334 
01335   /* clear received options */
01336   dhcp_clear_all_options(dhcp);
01337   /* check that beginning of dhcp_msg (up to and including chaddr) is in first pbuf */
01338   if (p->len < DHCP_SNAME_OFS) {
01339     return ERR_BUF;
01340   }
01341   dhcp->msg_in = (struct dhcp_msg *)p->payload;
01342 #if LWIP_DHCP_BOOTP_FILE
01343   /* clear boot file name */
01344   dhcp->boot_file_name[0] = 0;
01345 #endif /* LWIP_DHCP_BOOTP_FILE */
01346 
01347   /* parse options */
01348 
01349   /* start with options field */
01350   options_idx = DHCP_OPTIONS_OFS;
01351   /* parse options to the end of the received packet */
01352   options_idx_max = p->tot_len;
01353 again:
01354   q = p;
01355   while((q != NULL) && (options_idx >= q->len)) {
01356     options_idx -= q->len;
01357     options_idx_max -= q->len;
01358     q = q->next;
01359   }
01360   if (q == NULL) {
01361     return ERR_BUF;
01362   }
01363   offset = options_idx;
01364   offset_max = options_idx_max;
01365   options = (u8_t*)q->payload;
01366   /* at least 1 byte to read and no end marker, then at least 3 bytes to read? */
01367   while((q != NULL) && (options[offset] != DHCP_OPTION_END) && (offset < offset_max)) {
01368     u8_t op = options[offset];
01369     u8_t len;
01370     u8_t decode_len = 0;
01371     int decode_idx = -1;
01372     u16_t val_offset = offset + 2;
01373     /* len byte might be in the next pbuf */
01374     if (offset + 1 < q->len) {
01375       len = options[offset + 1];
01376     } else {
01377       len = (q->next != NULL ? ((u8_t*)q->next->payload)[0] : 0);
01378     }
01379     /* LWIP_DEBUGF(DHCP_DEBUG, ("msg_offset=%"U16_F", q->len=%"U16_F, msg_offset, q->len)); */
01380     decode_len = len;
01381     switch(op) {
01382       /* case(DHCP_OPTION_END): handled above */
01383       case(DHCP_OPTION_PAD):
01384         /* special option: no len encoded */
01385         decode_len = len = 0;
01386         /* will be increased below */
01387         offset--;
01388         break;
01389       case(DHCP_OPTION_SUBNET_MASK):
01390         LWIP_ASSERT("len == 4", len == 4);
01391         decode_idx = DHCP_OPTION_IDX_SUBNET_MASK;
01392         break;
01393       case(DHCP_OPTION_ROUTER):
01394         decode_len = 4; /* only copy the first given router */
01395         LWIP_ASSERT("len >= decode_len", len >= decode_len);
01396         decode_idx = DHCP_OPTION_IDX_ROUTER;
01397         break;
01398       case(DHCP_OPTION_DNS_SERVER):
01399         /* special case: there might be more than one server */
01400         LWIP_ASSERT("len % 4 == 0", len % 4 == 0);
01401         /* limit number of DNS servers */
01402         decode_len = LWIP_MIN(len, 4 * DNS_MAX_SERVERS);
01403         LWIP_ASSERT("len >= decode_len", len >= decode_len);
01404         decode_idx = DHCP_OPTION_IDX_DNS_SERVER;
01405         break;
01406       case(DHCP_OPTION_LEASE_TIME):
01407         LWIP_ASSERT("len == 4", len == 4);
01408         decode_idx = DHCP_OPTION_IDX_LEASE_TIME;
01409         break;
01410       case(DHCP_OPTION_OVERLOAD):
01411         LWIP_ASSERT("len == 1", len == 1);
01412         decode_idx = DHCP_OPTION_IDX_OVERLOAD;
01413         break;
01414       case(DHCP_OPTION_MESSAGE_TYPE):
01415         LWIP_ASSERT("len == 1", len == 1);
01416         decode_idx = DHCP_OPTION_IDX_MSG_TYPE;
01417         break;
01418       case(DHCP_OPTION_SERVER_ID):
01419         LWIP_ASSERT("len == 4", len == 4);
01420         decode_idx = DHCP_OPTION_IDX_SERVER_ID;
01421         break;
01422       case(DHCP_OPTION_T1):
01423         LWIP_ASSERT("len == 4", len == 4);
01424         decode_idx = DHCP_OPTION_IDX_T1;
01425         break;
01426       case(DHCP_OPTION_T2):
01427         LWIP_ASSERT("len == 4", len == 4);
01428         decode_idx = DHCP_OPTION_IDX_T2;
01429         break;
01430       default:
01431         decode_len = 0;
01432         LWIP_DEBUGF(DHCP_DEBUG, ("skipping option %"U16_F" in options\n", op));
01433         break;
01434     }
01435     offset += len + 2;
01436     if (decode_len > 0) {
01437       u32_t value = 0;
01438       u16_t copy_len;
01439 decode_next:
01440       LWIP_ASSERT("check decode_idx", decode_idx >= 0 && decode_idx < DHCP_OPTION_IDX_MAX);
01441       LWIP_ASSERT("option already decoded", !dhcp_option_given(dhcp, decode_idx));
01442       copy_len = LWIP_MIN(decode_len, 4);
01443       pbuf_copy_partial(q, &value, copy_len, val_offset);
01444       if (decode_len > 4) {
01445         /* decode more than one u32_t */
01446         LWIP_ASSERT("decode_len % 4 == 0", decode_len % 4 == 0);
01447         dhcp_got_option(dhcp, decode_idx);
01448         dhcp_set_option_value(dhcp, decode_idx, htonl(value));
01449         decode_len -= 4;
01450         val_offset += 4;
01451         decode_idx++;
01452         goto decode_next;
01453       } else if (decode_len == 4) {
01454         value = ntohl(value);
01455       } else {
01456         LWIP_ASSERT("invalid decode_len", decode_len == 1);
01457         value = ((u8_t*)&value)[0];
01458       }
01459       dhcp_got_option(dhcp, decode_idx);
01460       dhcp_set_option_value(dhcp, decode_idx, value);
01461     }
01462     if (offset >= q->len) {
01463       offset -= q->len;
01464       offset_max -= q->len;
01465       q = q->next;
01466       options = (u8_t*)q->payload;
01467     }
01468   }
01469   /* is this an overloaded message? */
01470   if (dhcp_option_given(dhcp, DHCP_OPTION_IDX_OVERLOAD)) {
01471     u32_t overload = dhcp_get_option_value(dhcp, DHCP_OPTION_IDX_OVERLOAD);
01472     dhcp_clear_option(dhcp, DHCP_OPTION_IDX_OVERLOAD);
01473     if (overload == DHCP_OVERLOAD_FILE) {
01474       parse_file_as_options = 1;
01475       LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE, ("overloaded file field\n"));
01476     } else if (overload == DHCP_OVERLOAD_SNAME) {
01477       parse_sname_as_options = 1;
01478       LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE, ("overloaded sname field\n"));
01479     } else if (overload == DHCP_OVERLOAD_SNAME_FILE) {
01480       parse_sname_as_options = 1;
01481       parse_file_as_options = 1;
01482       LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE, ("overloaded sname and file field\n"));
01483     } else {
01484       LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE, ("invalid overload option: %d\n", (int)overload));
01485     }
01486 #if LWIP_DHCP_BOOTP_FILE
01487     if (!parse_file_as_options) {
01488       /* only do this for ACK messages */
01489       if (dhcp_option_given(dhcp, DHCP_OPTION_IDX_MSG_TYPE) &&
01490         (dhcp_get_option_value(dhcp, DHCP_OPTION_IDX_MSG_TYPE) == DHCP_ACK))
01491       /* copy bootp file name, don't care for sname (server hostname) */
01492       pbuf_copy_partial(p, dhcp->boot_file_name, DHCP_FILE_LEN-1, DHCP_FILE_OFS);
01493       /* make sure the string is really NULL-terminated */
01494       dhcp->boot_file_name[DHCP_FILE_LEN-1] = 0;
01495     }
01496 #endif /* LWIP_DHCP_BOOTP_FILE */
01497   }
01498   if (parse_file_as_options) {
01499     /* if both are overloaded, parse file first and then sname (RFC 2131 ch. 4.1) */
01500     parse_file_as_options = 0;
01501     options_idx = DHCP_FILE_OFS;
01502     options_idx_max = DHCP_FILE_OFS + DHCP_FILE_LEN;
01503     goto again;
01504   } else if (parse_sname_as_options) {
01505     parse_sname_as_options = 0;
01506     options_idx = DHCP_SNAME_OFS;
01507     options_idx_max = DHCP_SNAME_OFS + DHCP_SNAME_LEN;
01508     goto again;
01509   }
01510   return ERR_OK;
01511 }
01512 
01513 /**
01514  * If an incoming DHCP message is in response to us, then trigger the state machine
01515  */
01516 static void
01517 dhcp_recv(void *arg, struct udp_pcb *pcb, struct pbuf *p, ip_addr_t *addr, u16_t port)
01518 {
01519   struct netif *netif = (struct netif *)arg;
01520   struct dhcp *dhcp = netif->dhcp;
01521   struct dhcp_msg *reply_msg = (struct dhcp_msg *)p->payload;
01522   u8_t msg_type;
01523   u8_t i;
01524   LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE, ("dhcp_recv(pbuf = %p) from DHCP server %"U16_F".%"U16_F".%"U16_F".%"U16_F" port %"U16_F"\n", (void*)p,
01525     ip4_addr1_16(addr), ip4_addr2_16(addr), ip4_addr3_16(addr), ip4_addr4_16(addr), port));
01526   LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE, ("pbuf->len = %"U16_F"\n", p->len));
01527   LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE, ("pbuf->tot_len = %"U16_F"\n", p->tot_len));
01528   /* prevent warnings about unused arguments */
01529   LWIP_UNUSED_ARG(pcb);
01530   LWIP_UNUSED_ARG(addr);
01531   LWIP_UNUSED_ARG(port);
01532 
01533   LWIP_ASSERT("reply wasn't freed", dhcp->msg_in == NULL);
01534 
01535   if (p->len < DHCP_MIN_REPLY_LEN) {
01536     LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_LEVEL_WARNING, ("DHCP reply message or pbuf too short\n"));
01537     goto free_pbuf_and_return;
01538   }
01539 
01540   if (reply_msg->op != DHCP_BOOTREPLY) {
01541     LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_LEVEL_WARNING, ("not a DHCP reply message, but type %"U16_F"\n", (u16_t)reply_msg->op));
01542     goto free_pbuf_and_return;
01543   }
01544   /* iterate through hardware address and match against DHCP message */
01545   for (i = 0; i < netif->hwaddr_len; i++) {
01546     if (netif->hwaddr[i] != reply_msg->chaddr[i]) {
01547       LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_LEVEL_WARNING,
01548         ("netif->hwaddr[%"U16_F"]==%02"X16_F" != reply_msg->chaddr[%"U16_F"]==%02"X16_F"\n",
01549         (u16_t)i, (u16_t)netif->hwaddr[i], (u16_t)i, (u16_t)reply_msg->chaddr[i]));
01550       goto free_pbuf_and_return;
01551     }
01552   }
01553   /* match transaction ID against what we expected */
01554   if (ntohl(reply_msg->xid) != dhcp->xid) {
01555     LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_LEVEL_WARNING,
01556       ("transaction id mismatch reply_msg->xid(%"X32_F")!=dhcp->xid(%"X32_F")\n",ntohl(reply_msg->xid),dhcp->xid));
01557     goto free_pbuf_and_return;
01558   }
01559   /* option fields could be unfold? */
01560   if (dhcp_parse_reply(dhcp, p) != ERR_OK) {
01561     LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_LEVEL_SERIOUS,
01562       ("problem unfolding DHCP message - too short on memory?\n"));
01563     goto free_pbuf_and_return;
01564   }
01565 
01566   LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE, ("searching DHCP_OPTION_MESSAGE_TYPE\n"));
01567   /* obtain pointer to DHCP message type */
01568   if (!dhcp_option_given(dhcp, DHCP_OPTION_IDX_MSG_TYPE)) {
01569     LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_LEVEL_WARNING, ("DHCP_OPTION_MESSAGE_TYPE option not found\n"));
01570     goto free_pbuf_and_return;
01571   }
01572 
01573   /* read DHCP message type */
01574   msg_type = (u8_t)dhcp_get_option_value(dhcp, DHCP_OPTION_IDX_MSG_TYPE);
01575   /* message type is DHCP ACK? */
01576   if (msg_type == DHCP_ACK) {
01577     LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE, ("DHCP_ACK received\n"));
01578     /* in requesting state? */
01579     if (dhcp->state == DHCP_REQUESTING) {
01580       dhcp_handle_ack(netif);
01581 #if DHCP_DOES_ARP_CHECK
01582       /* check if the acknowledged lease address is already in use */
01583       dhcp_check(netif);
01584 #else
01585       /* bind interface to the acknowledged lease address */
01586       dhcp_bind(netif);
01587 #endif
01588     }
01589     /* already bound to the given lease address? */
01590     else if ((dhcp->state == DHCP_REBOOTING) || (dhcp->state == DHCP_REBINDING) || (dhcp->state == DHCP_RENEWING)) {
01591       dhcp_bind(netif);
01592     }
01593   }
01594   /* received a DHCP_NAK in appropriate state? */
01595   else if ((msg_type == DHCP_NAK) &&
01596     ((dhcp->state == DHCP_REBOOTING) || (dhcp->state == DHCP_REQUESTING) ||
01597      (dhcp->state == DHCP_REBINDING) || (dhcp->state == DHCP_RENEWING  ))) {
01598     LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE, ("DHCP_NAK received\n"));
01599     dhcp_handle_nak(netif);
01600   }
01601   /* received a DHCP_OFFER in DHCP_SELECTING state? */
01602   else if ((msg_type == DHCP_OFFER) && (dhcp->state == DHCP_SELECTING)) {
01603     LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE, ("DHCP_OFFER received in DHCP_SELECTING state\n"));
01604     dhcp->request_timeout = 0;
01605     /* remember offered lease */
01606     dhcp_handle_offer(netif);
01607   }
01608 free_pbuf_and_return:
01609   dhcp->msg_in = NULL;
01610   pbuf_free(p);
01611 }
01612 
01613 /**
01614  * Create a DHCP request, fill in common headers
01615  *
01616  * @param netif the netif under DHCP control
01617  * @param dhcp dhcp control struct
01618  * @param message_type message type of the request
01619  */
01620 static err_t
01621 dhcp_create_msg(struct netif *netif, struct dhcp *dhcp, u8_t message_type)
01622 {
01623   u16_t i;
01624 #ifndef DHCP_GLOBAL_XID
01625   /** default global transaction identifier starting value (easy to match
01626    *  with a packet analyser). We simply increment for each new request.
01627    *  Predefine DHCP_GLOBAL_XID to a better value or a function call to generate one
01628    *  at runtime, any supporting function prototypes can be defined in DHCP_GLOBAL_XID_HEADER */
01629   static u32_t xid = 0xABCD0000;
01630 #else
01631   static u32_t xid;
01632   static u8_t xid_initialised = 0;
01633   if (!xid_initialised) {
01634     xid = DHCP_GLOBAL_XID;
01635     xid_initialised = !xid_initialised;
01636   }
01637 #endif
01638   LWIP_ERROR("dhcp_create_msg: netif != NULL", (netif != NULL), return ERR_ARG;);
01639   LWIP_ERROR("dhcp_create_msg: dhcp != NULL", (dhcp != NULL), return ERR_VAL;);
01640   LWIP_ASSERT("dhcp_create_msg: dhcp->p_out == NULL", dhcp->p_out == NULL);
01641   LWIP_ASSERT("dhcp_create_msg: dhcp->msg_out == NULL", dhcp->msg_out == NULL);
01642   dhcp->p_out = pbuf_alloc(PBUF_TRANSPORT, sizeof(struct dhcp_msg), PBUF_RAM);
01643   if (dhcp->p_out == NULL) {
01644     LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_LEVEL_SERIOUS,
01645       ("dhcp_create_msg(): could not allocate pbuf\n"));
01646     return ERR_MEM;
01647   }
01648   LWIP_ASSERT("dhcp_create_msg: check that first pbuf can hold struct dhcp_msg",
01649            (dhcp->p_out->len >= sizeof(struct dhcp_msg)));
01650 
01651   /* reuse transaction identifier in retransmissions */
01652   if (dhcp->tries == 0) {
01653       xid++;
01654   }
01655   dhcp->xid = xid;
01656   LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE,
01657               ("transaction id xid(%"X32_F")\n", xid));
01658 
01659   dhcp->msg_out = (struct dhcp_msg *)dhcp->p_out->payload;
01660 
01661   dhcp->msg_out->op = DHCP_BOOTREQUEST;
01662   /* TODO: make link layer independent */
01663   dhcp->msg_out->htype = DHCP_HTYPE_ETH;
01664   dhcp->msg_out->hlen = netif->hwaddr_len;
01665   dhcp->msg_out->hops = 0;
01666   dhcp->msg_out->xid = htonl(dhcp->xid);
01667   dhcp->msg_out->secs = 0;
01668   /* we don't need the broadcast flag since we can receive unicast traffic
01669      before being fully configured! */
01670   dhcp->msg_out->flags = 0;
01671   ip_addr_set_zero(&dhcp->msg_out->ciaddr);
01672   /* set ciaddr to netif->ip_addr based on message_type and state */
01673   if ((message_type == DHCP_INFORM) || (message_type == DHCP_DECLINE) ||
01674       ((message_type == DHCP_REQUEST) && /* DHCP_BOUND not used for sending! */
01675        ((dhcp->state==DHCP_RENEWING) || dhcp->state==DHCP_REBINDING))) {
01676     ip_addr_copy(dhcp->msg_out->ciaddr, netif->ip_addr);
01677   }
01678   ip_addr_set_zero(&dhcp->msg_out->yiaddr);
01679   ip_addr_set_zero(&dhcp->msg_out->siaddr);
01680   ip_addr_set_zero(&dhcp->msg_out->giaddr);
01681   for (i = 0; i < DHCP_CHADDR_LEN; i++) {
01682     /* copy netif hardware address, pad with zeroes */
01683     dhcp->msg_out->chaddr[i] = (i < netif->hwaddr_len) ? netif->hwaddr[i] : 0/* pad byte*/;
01684   }
01685   for (i = 0; i < DHCP_SNAME_LEN; i++) {
01686     dhcp->msg_out->sname[i] = 0;
01687   }
01688   for (i = 0; i < DHCP_FILE_LEN; i++) {
01689     dhcp->msg_out->file[i] = 0;
01690   }
01691   dhcp->msg_out->cookie = PP_HTONL(DHCP_MAGIC_COOKIE);
01692   dhcp->options_out_len = 0;
01693   /* fill options field with an incrementing array (for debugging purposes) */
01694   for (i = 0; i < DHCP_OPTIONS_LEN; i++) {
01695     dhcp->msg_out->options[i] = (u8_t)i; /* for debugging only, no matter if truncated */
01696   }
01697   /* Add option MESSAGE_TYPE */
01698   dhcp_option(dhcp, DHCP_OPTION_MESSAGE_TYPE, DHCP_OPTION_MESSAGE_TYPE_LEN);
01699   dhcp_option_byte(dhcp, message_type);
01700   return ERR_OK;
01701 }
01702 
01703 /**
01704  * Free previously allocated memory used to send a DHCP request.
01705  *
01706  * @param dhcp the dhcp struct to free the request from
01707  */
01708 static void
01709 dhcp_delete_msg(struct dhcp *dhcp)
01710 {
01711   LWIP_ERROR("dhcp_delete_msg: dhcp != NULL", (dhcp != NULL), return;);
01712   LWIP_ASSERT("dhcp_delete_msg: dhcp->p_out != NULL", dhcp->p_out != NULL);
01713   LWIP_ASSERT("dhcp_delete_msg: dhcp->msg_out != NULL", dhcp->msg_out != NULL);
01714   if (dhcp->p_out != NULL) {
01715     pbuf_free(dhcp->p_out);
01716   }
01717   dhcp->p_out = NULL;
01718   dhcp->msg_out = NULL;
01719 }
01720 
01721 /**
01722  * Add a DHCP message trailer
01723  *
01724  * Adds the END option to the DHCP message, and if
01725  * necessary, up to three padding bytes.
01726  *
01727  * @param dhcp DHCP state structure
01728  */
01729 static void
01730 dhcp_option_trailer(struct dhcp *dhcp)
01731 {
01732   LWIP_ERROR("dhcp_option_trailer: dhcp != NULL", (dhcp != NULL), return;);
01733   LWIP_ASSERT("dhcp_option_trailer: dhcp->msg_out != NULL\n", dhcp->msg_out != NULL);
01734   LWIP_ASSERT("dhcp_option_trailer: dhcp->options_out_len < DHCP_OPTIONS_LEN\n", dhcp->options_out_len < DHCP_OPTIONS_LEN);
01735   dhcp->msg_out->options[dhcp->options_out_len++] = DHCP_OPTION_END;
01736   /* packet is too small, or not 4 byte aligned? */
01737   while ((dhcp->options_out_len < DHCP_MIN_OPTIONS_LEN) || (dhcp->options_out_len & 3)) {
01738     /* LWIP_DEBUGF(DHCP_DEBUG,("dhcp_option_trailer:dhcp->options_out_len=%"U16_F", DHCP_OPTIONS_LEN=%"U16_F, dhcp->options_out_len, DHCP_OPTIONS_LEN)); */
01739     LWIP_ASSERT("dhcp_option_trailer: dhcp->options_out_len < DHCP_OPTIONS_LEN\n", dhcp->options_out_len < DHCP_OPTIONS_LEN);
01740     /* add a fill/padding byte */
01741     dhcp->msg_out->options[dhcp->options_out_len++] = 0;
01742   }
01743 }
01744 
01745 #endif /* LWIP_DHCP */