dhcp.c

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 /**
00596  * Start DHCP negotiation for a network interface.
00597  *
00598  * If no DHCP client instance was attached to this interface,
00599  * a new client is created first. If a DHCP client instance
00600  * was already present, it restarts negotiation.
00601  *
00602  * @param netif The lwIP network interface
00603  * @return lwIP error code
00604  * - ERR_OK - No error
00605  * - ERR_MEM - Out of memory
00606  */
00607 err_t
00608 dhcp_start(struct netif *netif)
00609 {
00610   struct dhcp *dhcp;
00611   err_t result = ERR_OK;
00612 
00613   LWIP_ERROR("netif != NULL", (netif != NULL), return ERR_ARG;);
00614   dhcp = netif->dhcp;
00615   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));
00616   /* Remove the flag that says this netif is handled by DHCP,
00617      it is set when we succeeded starting. */
00618   netif->flags &= ~NETIF_FLAG_DHCP;
00619 
00620   /* check hwtype of the netif */
00621   if ((netif->flags & NETIF_FLAG_ETHARP) == 0) {
00622     LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE, ("dhcp_start(): No ETHARP netif\n"));
00623     return ERR_ARG;
00624   }
00625 
00626   /* check MTU of the netif */
00627   if (netif->mtu < DHCP_MAX_MSG_LEN_MIN_REQUIRED) {
00628     LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE, ("dhcp_start(): Cannot use this netif with DHCP: MTU is too small\n"));
00629     return ERR_MEM;
00630   }
00631 
00632   /* no DHCP client attached yet? */
00633   if (dhcp == NULL) {
00634     LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE, ("dhcp_start(): starting new DHCP client\n"));
00635     dhcp = (struct dhcp *)mem_malloc(sizeof(struct dhcp));
00636     if (dhcp == NULL) {
00637       LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE, ("dhcp_start(): could not allocate dhcp\n"));
00638       return ERR_MEM;
00639     }
00640     /* store this dhcp client in the netif */
00641     netif->dhcp = dhcp;
00642     LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE, ("dhcp_start(): allocated dhcp"));
00643   /* already has DHCP client attached */
00644   } else {
00645     LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE, ("dhcp_start(): restarting DHCP configuration\n"));
00646     if (dhcp->pcb != NULL) {
00647       udp_remove(dhcp->pcb);
00648     }
00649     LWIP_ASSERT("pbuf p_out wasn't freed", dhcp->p_out == NULL);
00650     LWIP_ASSERT("reply wasn't freed", dhcp->msg_in == NULL );
00651   }
00652     
00653   /* clear data structure */
00654   memset(dhcp, 0, sizeof(struct dhcp));
00655   /* dhcp_set_state(&dhcp, DHCP_OFF); */
00656   /* allocate UDP PCB */
00657   dhcp->pcb = udp_new();
00658   if (dhcp->pcb == NULL) {
00659     LWIP_DEBUGF(DHCP_DEBUG  | LWIP_DBG_TRACE, ("dhcp_start(): could not obtain pcb\n"));
00660     return ERR_MEM;
00661   }
00662   dhcp->pcb->so_options |= SOF_BROADCAST;
00663   /* set up local and remote port for the pcb */
00664   udp_bind(dhcp->pcb, IP_ADDR_ANY, DHCP_CLIENT_PORT);
00665   udp_connect(dhcp->pcb, IP_ADDR_ANY, DHCP_SERVER_PORT);
00666   /* set up the recv callback and argument */
00667   udp_recv(dhcp->pcb, dhcp_recv, netif);
00668   LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE, ("dhcp_start(): starting DHCP configuration\n"));
00669   /* (re)start the DHCP negotiation */
00670   result = dhcp_discover(netif);
00671   if (result != ERR_OK) {
00672     /* free resources allocated above */
00673     dhcp_stop(netif);
00674     return ERR_MEM;
00675   }
00676   /* Set the flag that says this netif is handled by DHCP. */
00677   netif->flags |= NETIF_FLAG_DHCP;
00678   return result;
00679 }
00680 
00681 /**
00682  * Inform a DHCP server of our manual configuration.
00683  *
00684  * This informs DHCP servers of our fixed IP address configuration
00685  * by sending an INFORM message. It does not involve DHCP address
00686  * configuration, it is just here to be nice to the network.
00687  *
00688  * @param netif The lwIP network interface
00689  */
00690 void
00691 dhcp_inform(struct netif *netif)
00692 {
00693   struct dhcp dhcp;
00694   err_t result = ERR_OK;
00695   struct udp_pcb *pcb;
00696 
00697   LWIP_ERROR("netif != NULL", (netif != NULL), return;);
00698 
00699   memset(&dhcp, 0, sizeof(struct dhcp));
00700   dhcp_set_state(&dhcp, DHCP_INFORM);
00701 
00702   if ((netif->dhcp != NULL) && (netif->dhcp->pcb != NULL)) {
00703     /* re-use existing pcb */
00704     pcb = netif->dhcp->pcb;
00705   } else {
00706     pcb = udp_new();
00707     if (pcb == NULL) {
00708       LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_LEVEL_SERIOUS, ("dhcp_inform(): could not obtain pcb"));
00709       return;
00710     }
00711     dhcp.pcb = pcb;
00712     dhcp.pcb->so_options |= SOF_BROADCAST;
00713     udp_bind(dhcp.pcb, IP_ADDR_ANY, DHCP_CLIENT_PORT);
00714     LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE, ("dhcp_inform(): created new udp pcb\n"));
00715   }
00716   /* create and initialize the DHCP message header */
00717   result = dhcp_create_msg(netif, &dhcp, DHCP_INFORM);
00718   if (result == ERR_OK) {
00719     dhcp_option(&dhcp, DHCP_OPTION_MAX_MSG_SIZE, DHCP_OPTION_MAX_MSG_SIZE_LEN);
00720     dhcp_option_short(&dhcp, DHCP_MAX_MSG_LEN(netif));
00721 
00722     dhcp_option_trailer(&dhcp);
00723 
00724     pbuf_realloc(dhcp.p_out, sizeof(struct dhcp_msg) - DHCP_OPTIONS_LEN + dhcp.options_out_len);
00725 
00726     LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE, ("dhcp_inform: INFORMING\n"));
00727     udp_sendto_if(pcb, dhcp.p_out, IP_ADDR_BROADCAST, DHCP_SERVER_PORT, netif);
00728     dhcp_delete_msg(&dhcp);
00729   } else {
00730     LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_LEVEL_SERIOUS, ("dhcp_inform: could not allocate DHCP request\n"));
00731   }
00732 
00733   if (dhcp.pcb != NULL) {
00734     /* otherwise, the existing pcb was used */
00735     udp_remove(dhcp.pcb);
00736   }
00737 }
00738 
00739 /** Handle a possible change in the network configuration.
00740  *
00741  * This enters the REBOOTING state to verify that the currently bound
00742  * address is still valid.
00743  */
00744 void
00745 dhcp_network_changed(struct netif *netif)
00746 {
00747   struct dhcp *dhcp = netif->dhcp;
00748   if (!dhcp)
00749     return;
00750   switch (dhcp->state) {
00751   case DHCP_REBINDING:
00752   case DHCP_RENEWING:
00753   case DHCP_BOUND:
00754   case DHCP_REBOOTING:
00755     netif_set_down(netif);
00756     dhcp->tries = 0;
00757     dhcp_reboot(netif);
00758     break;
00759   case DHCP_OFF:
00760     /* stay off */
00761     break;
00762   default:
00763     dhcp->tries = 0;
00764     dhcp_discover(netif);
00765     break;
00766   }
00767 }
00768 
00769 #if DHCP_DOES_ARP_CHECK
00770 /**
00771  * Match an ARP reply with the offered IP address.
00772  *
00773  * @param netif the network interface on which the reply was received
00774  * @param addr The IP address we received a reply from
00775  */
00776 void dhcp_arp_reply(struct netif *netif, ip_addr_t *addr)
00777 {
00778   LWIP_ERROR("netif != NULL", (netif != NULL), return;);
00779   LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE, ("dhcp_arp_reply()\n"));
00780   /* is a DHCP client doing an ARP check? */
00781   if ((netif->dhcp != NULL) && (netif->dhcp->state == DHCP_CHECKING)) {
00782     LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE, ("dhcp_arp_reply(): CHECKING, arp reply for 0x%08"X32_F"\n",
00783       ip4_addr_get_u32(addr)));
00784     /* did a host respond with the address we
00785        were offered by the DHCP server? */
00786     if (ip_addr_cmp(addr, &netif->dhcp->offered_ip_addr)) {
00787       /* we will not accept the offered address */
00788       LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE | LWIP_DBG_LEVEL_WARNING,
00789         ("dhcp_arp_reply(): arp reply matched with offered address, declining\n"));
00790       dhcp_decline(netif);
00791     }
00792   }
00793 }
00794 
00795 /**
00796  * Decline an offered lease.
00797  *
00798  * Tell the DHCP server we do not accept the offered address.
00799  * One reason to decline the lease is when we find out the address
00800  * is already in use by another host (through ARP).
00801  *
00802  * @param netif the netif under DHCP control
00803  */
00804 static err_t
00805 dhcp_decline(struct netif *netif)
00806 {
00807   struct dhcp *dhcp = netif->dhcp;
00808   err_t result = ERR_OK;
00809   u16_t msecs;
00810   LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE, ("dhcp_decline()\n"));
00811   dhcp_set_state(dhcp, DHCP_BACKING_OFF);
00812   /* create and initialize the DHCP message header */
00813   result = dhcp_create_msg(netif, dhcp, DHCP_DECLINE);
00814   if (result == ERR_OK) {
00815     dhcp_option(dhcp, DHCP_OPTION_REQUESTED_IP, 4);
00816     dhcp_option_long(dhcp, ntohl(ip4_addr_get_u32(&dhcp->offered_ip_addr)));
00817 
00818     dhcp_option_trailer(dhcp);
00819     /* resize pbuf to reflect true size of options */
00820     pbuf_realloc(dhcp->p_out, sizeof(struct dhcp_msg) - DHCP_OPTIONS_LEN + dhcp->options_out_len);
00821 
00822     /* per section 4.4.4, broadcast DECLINE messages */
00823     udp_sendto_if(dhcp->pcb, dhcp->p_out, IP_ADDR_BROADCAST, DHCP_SERVER_PORT, netif);
00824     dhcp_delete_msg(dhcp);
00825     LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE, ("dhcp_decline: BACKING OFF\n"));
00826   } else {
00827     LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_LEVEL_SERIOUS,
00828       ("dhcp_decline: could not allocate DHCP request\n"));
00829   }
00830   dhcp->tries++;
00831   msecs = 10*1000;
00832   dhcp->request_timeout = (msecs + DHCP_FINE_TIMER_MSECS - 1) / DHCP_FINE_TIMER_MSECS;
00833   LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE, ("dhcp_decline(): set request timeout %"U16_F" msecs\n", msecs));
00834   return result;
00835 }
00836 #endif /* DHCP_DOES_ARP_CHECK */
00837 
00838 
00839 /**
00840  * Start the DHCP process, discover a DHCP server.
00841  *
00842  * @param netif the netif under DHCP control
00843  */
00844 static err_t
00845 dhcp_discover(struct netif *netif)
00846 {
00847   struct dhcp *dhcp = netif->dhcp;
00848   err_t result = ERR_OK;
00849   u16_t msecs;
00850   LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE, ("dhcp_discover()\n"));
00851   ip_addr_set_any(&dhcp->offered_ip_addr);
00852   dhcp_set_state(dhcp, DHCP_SELECTING);
00853   /* create and initialize the DHCP message header */
00854   result = dhcp_create_msg(netif, dhcp, DHCP_DISCOVER);
00855   if (result == ERR_OK) {
00856     LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE, ("dhcp_discover: making request\n"));
00857 
00858     dhcp_option(dhcp, DHCP_OPTION_MAX_MSG_SIZE, DHCP_OPTION_MAX_MSG_SIZE_LEN);
00859     dhcp_option_short(dhcp, DHCP_MAX_MSG_LEN(netif));
00860 
00861     dhcp_option(dhcp, DHCP_OPTION_PARAMETER_REQUEST_LIST, 4/*num options*/);
00862     dhcp_option_byte(dhcp, DHCP_OPTION_SUBNET_MASK);
00863     dhcp_option_byte(dhcp, DHCP_OPTION_ROUTER);
00864     dhcp_option_byte(dhcp, DHCP_OPTION_BROADCAST);
00865     dhcp_option_byte(dhcp, DHCP_OPTION_DNS_SERVER);
00866 
00867     dhcp_option_trailer(dhcp);
00868 
00869     LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE, ("dhcp_discover: realloc()ing\n"));
00870     pbuf_realloc(dhcp->p_out, sizeof(struct dhcp_msg) - DHCP_OPTIONS_LEN + dhcp->options_out_len);
00871 
00872     LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE, ("dhcp_discover: sendto(DISCOVER, IP_ADDR_BROADCAST, DHCP_SERVER_PORT)\n"));
00873     udp_sendto_if(dhcp->pcb, dhcp->p_out, IP_ADDR_BROADCAST, DHCP_SERVER_PORT, netif);
00874     LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE, ("dhcp_discover: deleting()ing\n"));
00875     dhcp_delete_msg(dhcp);
00876     LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE, ("dhcp_discover: SELECTING\n"));
00877   } else {
00878     LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_LEVEL_SERIOUS, ("dhcp_discover: could not allocate DHCP request\n"));
00879   }
00880   dhcp->tries++;
00881 #if LWIP_DHCP_AUTOIP_COOP
00882   if(dhcp->tries >= LWIP_DHCP_AUTOIP_COOP_TRIES && dhcp->autoip_coop_state == DHCP_AUTOIP_COOP_STATE_OFF) {
00883     dhcp->autoip_coop_state = DHCP_AUTOIP_COOP_STATE_ON;
00884     autoip_start(netif);
00885   }
00886 #endif /* LWIP_DHCP_AUTOIP_COOP */
00887   msecs = (dhcp->tries < 6 ? 1 << dhcp->tries : 60) * 1000;
00888   dhcp->request_timeout = (msecs + DHCP_FINE_TIMER_MSECS - 1) / DHCP_FINE_TIMER_MSECS;
00889   LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE, ("dhcp_discover(): set request timeout %"U16_F" msecs\n", msecs));
00890   return result;
00891 }
00892 
00893 
00894 /**
00895  * Bind the interface to the offered IP address.
00896  *
00897  * @param netif network interface to bind to the offered address
00898  */
00899 static void
00900 dhcp_bind(struct netif *netif)
00901 {
00902   u32_t timeout;
00903   struct dhcp *dhcp;
00904   ip_addr_t sn_mask, gw_addr;
00905   LWIP_ERROR("dhcp_bind: netif != NULL", (netif != NULL), return;);
00906   dhcp = netif->dhcp;
00907   LWIP_ERROR("dhcp_bind: dhcp != NULL", (dhcp != NULL), return;);
00908   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));
00909 
00910   /* temporary DHCP lease? */
00911   if (dhcp->offered_t1_renew != 0xffffffffUL) {
00912     /* set renewal period timer */
00913     LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE, ("dhcp_bind(): t1 renewal timer %"U32_F" secs\n", dhcp->offered_t1_renew));
00914     timeout = (dhcp->offered_t1_renew + DHCP_COARSE_TIMER_SECS / 2) / DHCP_COARSE_TIMER_SECS;
00915     if(timeout > 0xffff) {
00916       timeout = 0xffff;
00917     }
00918     dhcp->t1_timeout = (u16_t)timeout;
00919     if (dhcp->t1_timeout == 0) {
00920       dhcp->t1_timeout = 1;
00921     }
00922     LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE, ("dhcp_bind(): set request timeout %"U32_F" msecs\n", dhcp->offered_t1_renew*1000));
00923   }
00924   /* set renewal period timer */
00925   if (dhcp->offered_t2_rebind != 0xffffffffUL) {
00926     LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE, ("dhcp_bind(): t2 rebind timer %"U32_F" secs\n", dhcp->offered_t2_rebind));
00927     timeout = (dhcp->offered_t2_rebind + DHCP_COARSE_TIMER_SECS / 2) / DHCP_COARSE_TIMER_SECS;
00928     if(timeout > 0xffff) {
00929       timeout = 0xffff;
00930     }
00931     dhcp->t2_timeout = (u16_t)timeout;
00932     if (dhcp->t2_timeout == 0) {
00933       dhcp->t2_timeout = 1;
00934     }
00935     LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE, ("dhcp_bind(): set request timeout %"U32_F" msecs\n", dhcp->offered_t2_rebind*1000));
00936   }
00937 
00938   if (dhcp->subnet_mask_given) {
00939     /* copy offered network mask */
00940     ip_addr_copy(sn_mask, dhcp->offered_sn_mask);
00941   } else {
00942     /* subnet mask not given, choose a safe subnet mask given the network class */
00943     u8_t first_octet = ip4_addr1(&dhcp->offered_ip_addr);
00944     if (first_octet <= 127) {
00945       ip4_addr_set_u32(&sn_mask, htonl(0xff000000));
00946     } else if (first_octet >= 192) {
00947       ip4_addr_set_u32(&sn_mask, htonl(0xffffff00));
00948     } else {
00949       ip4_addr_set_u32(&sn_mask, htonl(0xffff0000));
00950     }
00951   }
00952 
00953   ip_addr_copy(gw_addr, dhcp->offered_gw_addr);
00954   /* gateway address not given? */
00955   if (ip_addr_isany(&gw_addr)) {
00956     /* copy network address */
00957     ip_addr_get_network(&gw_addr, &dhcp->offered_ip_addr, &sn_mask);
00958     /* use first host address on network as gateway */
00959     ip4_addr_set_u32(&gw_addr, ip4_addr_get_u32(&gw_addr) | htonl(0x00000001));
00960   }
00961 
00962 #if LWIP_DHCP_AUTOIP_COOP
00963   if(dhcp->autoip_coop_state == DHCP_AUTOIP_COOP_STATE_ON) {
00964     autoip_stop(netif);
00965     dhcp->autoip_coop_state = DHCP_AUTOIP_COOP_STATE_OFF;
00966   }
00967 #endif /* LWIP_DHCP_AUTOIP_COOP */
00968 
00969   LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_STATE, ("dhcp_bind(): IP: 0x%08"X32_F"\n",
00970     ip4_addr_get_u32(&dhcp->offered_ip_addr)));
00971   netif_set_ipaddr(netif, &dhcp->offered_ip_addr);
00972   LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_STATE, ("dhcp_bind(): SN: 0x%08"X32_F"\n",
00973     ip4_addr_get_u32(&sn_mask)));
00974   netif_set_netmask(netif, &sn_mask);
00975   LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_STATE, ("dhcp_bind(): GW: 0x%08"X32_F"\n",
00976     ip4_addr_get_u32(&gw_addr)));
00977   netif_set_gw(netif, &gw_addr);
00978   /* bring the interface up */
00979   netif_set_up(netif);
00980   /* netif is now bound to DHCP leased address */
00981   dhcp_set_state(dhcp, DHCP_BOUND);
00982 }
00983 
00984 /**
00985  * Renew an existing DHCP lease at the involved DHCP server.
00986  *
00987  * @param netif network interface which must renew its lease
00988  */
00989 err_t
00990 dhcp_renew(struct netif *netif)
00991 {
00992   struct dhcp *dhcp = netif->dhcp;
00993   err_t result;
00994   u16_t msecs;
00995   LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE, ("dhcp_renew()\n"));
00996   dhcp_set_state(dhcp, DHCP_RENEWING);
00997 
00998   /* create and initialize the DHCP message header */
00999   result = dhcp_create_msg(netif, dhcp, DHCP_REQUEST);
01000   if (result == ERR_OK) {
01001     dhcp_option(dhcp, DHCP_OPTION_MAX_MSG_SIZE, DHCP_OPTION_MAX_MSG_SIZE_LEN);
01002     dhcp_option_short(dhcp, DHCP_MAX_MSG_LEN(netif));
01003 
01004 #if LWIP_NETIF_HOSTNAME
01005     if (netif->hostname != NULL) {
01006       const char *p = (const char*)netif->hostname;
01007       u8_t namelen = (u8_t)strlen(p);
01008       if (namelen > 0) {
01009         LWIP_ASSERT("DHCP: hostname is too long!", namelen < 255);
01010         dhcp_option(dhcp, DHCP_OPTION_HOSTNAME, namelen);
01011         while (*p) {
01012           dhcp_option_byte(dhcp, *p++);
01013         }
01014       }
01015     }
01016 #endif /* LWIP_NETIF_HOSTNAME */
01017 
01018 #if 0
01019     dhcp_option(dhcp, DHCP_OPTION_REQUESTED_IP, 4);
01020     dhcp_option_long(dhcp, ntohl(dhcp->offered_ip_addr.addr));
01021 #endif
01022 
01023 #if 0
01024     dhcp_option(dhcp, DHCP_OPTION_SERVER_ID, 4);
01025     dhcp_option_long(dhcp, ntohl(dhcp->server_ip_addr.addr));
01026 #endif
01027     /* append DHCP message trailer */
01028     dhcp_option_trailer(dhcp);
01029 
01030     pbuf_realloc(dhcp->p_out, sizeof(struct dhcp_msg) - DHCP_OPTIONS_LEN + dhcp->options_out_len);
01031 
01032     udp_sendto_if(dhcp->pcb, dhcp->p_out, &dhcp->server_ip_addr, DHCP_SERVER_PORT, netif);
01033     dhcp_delete_msg(dhcp);
01034 
01035     LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE, ("dhcp_renew: RENEWING\n"));
01036   } else {
01037     LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_LEVEL_SERIOUS, ("dhcp_renew: could not allocate DHCP request\n"));
01038   }
01039   dhcp->tries++;
01040   /* back-off on retries, but to a maximum of 20 seconds */
01041   msecs = dhcp->tries < 10 ? dhcp->tries * 2000 : 20 * 1000;
01042   dhcp->request_timeout = (msecs + DHCP_FINE_TIMER_MSECS - 1) / DHCP_FINE_TIMER_MSECS;
01043   LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE, ("dhcp_renew(): set request timeout %"U16_F" msecs\n", msecs));
01044   return result;
01045 }
01046 
01047 /**
01048  * Rebind with a DHCP server for an existing DHCP lease.
01049  *
01050  * @param netif network interface which must rebind with a DHCP server
01051  */
01052 static err_t
01053 dhcp_rebind(struct netif *netif)
01054 {
01055   struct dhcp *dhcp = netif->dhcp;
01056   err_t result;
01057   u16_t msecs;
01058   LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE, ("dhcp_rebind()\n"));
01059   dhcp_set_state(dhcp, DHCP_REBINDING);
01060 
01061   /* create and initialize the DHCP message header */
01062   result = dhcp_create_msg(netif, dhcp, DHCP_REQUEST);
01063   if (result == ERR_OK) {
01064     dhcp_option(dhcp, DHCP_OPTION_MAX_MSG_SIZE, DHCP_OPTION_MAX_MSG_SIZE_LEN);
01065     dhcp_option_short(dhcp, DHCP_MAX_MSG_LEN(netif));
01066 
01067 #if LWIP_NETIF_HOSTNAME
01068     if (netif->hostname != NULL) {
01069       const char *p = (const char*)netif->hostname;
01070       u8_t namelen = (u8_t)strlen(p);
01071       if (namelen > 0) {
01072         LWIP_ASSERT("DHCP: hostname is too long!", namelen < 255);
01073         dhcp_option(dhcp, DHCP_OPTION_HOSTNAME, namelen);
01074         while (*p) {
01075           dhcp_option_byte(dhcp, *p++);
01076         }
01077       }
01078     }
01079 #endif /* LWIP_NETIF_HOSTNAME */
01080 
01081 #if 0
01082     dhcp_option(dhcp, DHCP_OPTION_REQUESTED_IP, 4);
01083     dhcp_option_long(dhcp, ntohl(dhcp->offered_ip_addr.addr));
01084 
01085     dhcp_option(dhcp, DHCP_OPTION_SERVER_ID, 4);
01086     dhcp_option_long(dhcp, ntohl(dhcp->server_ip_addr.addr));
01087 #endif
01088 
01089     dhcp_option_trailer(dhcp);
01090 
01091     pbuf_realloc(dhcp->p_out, sizeof(struct dhcp_msg) - DHCP_OPTIONS_LEN + dhcp->options_out_len);
01092 
01093     /* broadcast to server */
01094     udp_sendto_if(dhcp->pcb, dhcp->p_out, IP_ADDR_BROADCAST, DHCP_SERVER_PORT, netif);
01095     dhcp_delete_msg(dhcp);
01096     LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE, ("dhcp_rebind: REBINDING\n"));
01097   } else {
01098     LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_LEVEL_SERIOUS, ("dhcp_rebind: could not allocate DHCP request\n"));
01099   }
01100   dhcp->tries++;
01101   msecs = dhcp->tries < 10 ? dhcp->tries * 1000 : 10 * 1000;
01102   dhcp->request_timeout = (msecs + DHCP_FINE_TIMER_MSECS - 1) / DHCP_FINE_TIMER_MSECS;
01103   LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE, ("dhcp_rebind(): set request timeout %"U16_F" msecs\n", msecs));
01104   return result;
01105 }
01106 
01107 /**
01108  * Enter REBOOTING state to verify an existing lease
01109  *
01110  * @param netif network interface which must reboot
01111  */
01112 static err_t
01113 dhcp_reboot(struct netif *netif)
01114 {
01115   struct dhcp *dhcp = netif->dhcp;
01116   err_t result;
01117   u16_t msecs;
01118   LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE, ("dhcp_reboot()\n"));
01119   dhcp_set_state(dhcp, DHCP_REBOOTING);
01120 
01121   /* create and initialize the DHCP message header */
01122   result = dhcp_create_msg(netif, dhcp, DHCP_REQUEST);
01123   if (result == ERR_OK) {
01124     dhcp_option(dhcp, DHCP_OPTION_MAX_MSG_SIZE, DHCP_OPTION_MAX_MSG_SIZE_LEN);
01125     dhcp_option_short(dhcp, 576);
01126 
01127     dhcp_option(dhcp, DHCP_OPTION_REQUESTED_IP, 4);
01128     dhcp_option_long(dhcp, ntohl(ip4_addr_get_u32(&dhcp->offered_ip_addr)));
01129 
01130     dhcp_option_trailer(dhcp);
01131 
01132     pbuf_realloc(dhcp->p_out, sizeof(struct dhcp_msg) - DHCP_OPTIONS_LEN + dhcp->options_out_len);
01133 
01134     /* broadcast to server */
01135     udp_sendto_if(dhcp->pcb, dhcp->p_out, IP_ADDR_BROADCAST, DHCP_SERVER_PORT, netif);
01136     dhcp_delete_msg(dhcp);
01137     LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE, ("dhcp_reboot: REBOOTING\n"));
01138   } else {
01139     LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_LEVEL_SERIOUS, ("dhcp_reboot: could not allocate DHCP request\n"));
01140   }
01141   dhcp->tries++;
01142   msecs = dhcp->tries < 10 ? dhcp->tries * 1000 : 10 * 1000;
01143   dhcp->request_timeout = (msecs + DHCP_FINE_TIMER_MSECS - 1) / DHCP_FINE_TIMER_MSECS;
01144   LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE, ("dhcp_reboot(): set request timeout %"U16_F" msecs\n", msecs));
01145   return result;
01146 }
01147 
01148 
01149 /**
01150  * Release a DHCP lease.
01151  *
01152  * @param netif network interface which must release its lease
01153  */
01154 err_t
01155 dhcp_release(struct netif *netif)
01156 {
01157   struct dhcp *dhcp = netif->dhcp;
01158   err_t result;
01159   u16_t msecs;
01160   LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE, ("dhcp_release()\n"));
01161 
01162   /* idle DHCP client */
01163   dhcp_set_state(dhcp, DHCP_OFF);
01164   /* clean old DHCP offer */
01165   ip_addr_set_zero(&dhcp->server_ip_addr);
01166   ip_addr_set_zero(&dhcp->offered_ip_addr);
01167   ip_addr_set_zero(&dhcp->offered_sn_mask);
01168   ip_addr_set_zero(&dhcp->offered_gw_addr);
01169 #if LWIP_DHCP_BOOTP_FILE
01170   ip_addr_set_zero(&dhcp->offered_si_addr);
01171 #endif /* LWIP_DHCP_BOOTP_FILE */
01172   dhcp->offered_t0_lease = dhcp->offered_t1_renew = dhcp->offered_t2_rebind = 0;
01173   
01174   /* create and initialize the DHCP message header */
01175   result = dhcp_create_msg(netif, dhcp, DHCP_RELEASE);
01176   if (result == ERR_OK) {
01177     dhcp_option_trailer(dhcp);
01178 
01179     pbuf_realloc(dhcp->p_out, sizeof(struct dhcp_msg) - DHCP_OPTIONS_LEN + dhcp->options_out_len);
01180 
01181     udp_sendto_if(dhcp->pcb, dhcp->p_out, &dhcp->server_ip_addr, DHCP_SERVER_PORT, netif);
01182     dhcp_delete_msg(dhcp);
01183     LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE, ("dhcp_release: RELEASED, DHCP_OFF\n"));
01184   } else {
01185     LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_LEVEL_SERIOUS, ("dhcp_release: could not allocate DHCP request\n"));
01186   }
01187   dhcp->tries++;
01188   msecs = dhcp->tries < 10 ? dhcp->tries * 1000 : 10 * 1000;
01189   dhcp->request_timeout = (msecs + DHCP_FINE_TIMER_MSECS - 1) / DHCP_FINE_TIMER_MSECS;
01190   LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE, ("dhcp_release(): set request timeout %"U16_F" msecs\n", msecs));
01191   /* bring the interface down */
01192   netif_set_down(netif);
01193   /* remove IP address from interface */
01194   netif_set_ipaddr(netif, IP_ADDR_ANY);
01195   netif_set_gw(netif, IP_ADDR_ANY);
01196   netif_set_netmask(netif, IP_ADDR_ANY);
01197   
01198   return result;
01199 }
01200 
01201 /**
01202  * Remove the DHCP client from the interface.
01203  *
01204  * @param netif The network interface to stop DHCP on
01205  */
01206 void
01207 dhcp_stop(struct netif *netif)
01208 {
01209   struct dhcp *dhcp = netif->dhcp;
01210   LWIP_ERROR("dhcp_stop: netif != NULL", (netif != NULL), return;);
01211   /* Remove the flag that says this netif is handled by DHCP. */
01212   netif->flags &= ~NETIF_FLAG_DHCP;
01213 
01214   LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE, ("dhcp_stop()\n"));
01215   /* netif is DHCP configured? */
01216   if (dhcp != NULL) {
01217 #if LWIP_DHCP_AUTOIP_COOP
01218     if(dhcp->autoip_coop_state == DHCP_AUTOIP_COOP_STATE_ON) {
01219       autoip_stop(netif);
01220       dhcp->autoip_coop_state = DHCP_AUTOIP_COOP_STATE_OFF;
01221     }
01222 #endif /* LWIP_DHCP_AUTOIP_COOP */
01223 
01224     if (dhcp->pcb != NULL) {
01225       udp_remove(dhcp->pcb);
01226       dhcp->pcb = NULL;
01227     }
01228     LWIP_ASSERT("reply wasn't freed", dhcp->msg_in == NULL);
01229     dhcp_set_state(dhcp, DHCP_OFF);
01230   }
01231 }
01232 
01233 /*
01234  * Set the DHCP state of a DHCP client.
01235  *
01236  * If the state changed, reset the number of tries.
01237  */
01238 static void
01239 dhcp_set_state(struct dhcp *dhcp, u8_t new_state)
01240 {
01241   if (new_state != dhcp->state) {
01242     dhcp->state = new_state;
01243     dhcp->tries = 0;
01244     dhcp->request_timeout = 0;
01245   }
01246 }
01247 
01248 /*
01249  * Concatenate an option type and length field to the outgoing
01250  * DHCP message.
01251  *
01252  */
01253 static void
01254 dhcp_option(struct dhcp *dhcp, u8_t option_type, u8_t option_len)
01255 {
01256   LWIP_ASSERT("dhcp_option: dhcp->options_out_len + 2 + option_len <= DHCP_OPTIONS_LEN", dhcp->options_out_len + 2U + option_len <= DHCP_OPTIONS_LEN);
01257   dhcp->msg_out->options[dhcp->options_out_len++] = option_type;
01258   dhcp->msg_out->options[dhcp->options_out_len++] = option_len;
01259 }
01260 /*
01261  * Concatenate a single byte to the outgoing DHCP message.
01262  *
01263  */
01264 static void
01265 dhcp_option_byte(struct dhcp *dhcp, u8_t value)
01266 {
01267   LWIP_ASSERT("dhcp_option_byte: dhcp->options_out_len < DHCP_OPTIONS_LEN", dhcp->options_out_len < DHCP_OPTIONS_LEN);
01268   dhcp->msg_out->options[dhcp->options_out_len++] = value;
01269 }
01270 
01271 static void
01272 dhcp_option_short(struct dhcp *dhcp, u16_t value)
01273 {
01274   LWIP_ASSERT("dhcp_option_short: dhcp->options_out_len + 2 <= DHCP_OPTIONS_LEN", dhcp->options_out_len + 2U <= DHCP_OPTIONS_LEN);
01275   dhcp->msg_out->options[dhcp->options_out_len++] = (u8_t)((value & 0xff00U) >> 8);
01276   dhcp->msg_out->options[dhcp->options_out_len++] = (u8_t) (value & 0x00ffU);
01277 }
01278 
01279 static void
01280 dhcp_option_long(struct dhcp *dhcp, u32_t value)
01281 {
01282   LWIP_ASSERT("dhcp_option_long: dhcp->options_out_len + 4 <= DHCP_OPTIONS_LEN", dhcp->options_out_len + 4U <= DHCP_OPTIONS_LEN);
01283   dhcp->msg_out->options[dhcp->options_out_len++] = (u8_t)((value & 0xff000000UL) >> 24);
01284   dhcp->msg_out->options[dhcp->options_out_len++] = (u8_t)((value & 0x00ff0000UL) >> 16);
01285   dhcp->msg_out->options[dhcp->options_out_len++] = (u8_t)((value & 0x0000ff00UL) >> 8);
01286   dhcp->msg_out->options[dhcp->options_out_len++] = (u8_t)((value & 0x000000ffUL));
01287 }
01288 
01289 /**
01290  * Extract the DHCP message and the DHCP options.
01291  *
01292  * Extract the DHCP message and the DHCP options, each into a contiguous
01293  * piece of memory. As a DHCP message is variable sized by its options,
01294  * and also allows overriding some fields for options, the easy approach
01295  * is to first unfold the options into a conitguous piece of memory, and
01296  * use that further on.
01297  *
01298  */
01299 static err_t
01300 dhcp_parse_reply(struct dhcp *dhcp, struct pbuf *p)
01301 {
01302   u8_t *options;
01303   u16_t offset;
01304   u16_t offset_max;
01305   u16_t options_idx;
01306   u16_t options_idx_max;
01307   struct pbuf *q;
01308   int parse_file_as_options = 0;
01309   int parse_sname_as_options = 0;
01310 
01311   /* clear received options */
01312   dhcp_clear_all_options(dhcp);
01313   /* check that beginning of dhcp_msg (up to and including chaddr) is in first pbuf */
01314   if (p->len < DHCP_SNAME_OFS) {
01315     return ERR_BUF;
01316   }
01317   dhcp->msg_in = (struct dhcp_msg *)p->payload;
01318 #if LWIP_DHCP_BOOTP_FILE
01319   /* clear boot file name */
01320   dhcp->boot_file_name[0] = 0;
01321 #endif /* LWIP_DHCP_BOOTP_FILE */
01322 
01323   /* parse options */
01324 
01325   /* start with options field */
01326   options_idx = DHCP_OPTIONS_OFS;
01327   /* parse options to the end of the received packet */
01328   options_idx_max = p->tot_len;
01329 again:
01330   q = p;
01331   while((q != NULL) && (options_idx >= q->len)) {
01332     options_idx -= q->len;
01333     options_idx_max -= q->len;
01334     q = q->next;
01335   }
01336   if (q == NULL) {
01337     return ERR_BUF;
01338   }
01339   offset = options_idx;
01340   offset_max = options_idx_max;
01341   options = (u8_t*)q->payload;
01342   /* at least 1 byte to read and no end marker, then at least 3 bytes to read? */
01343   while((q != NULL) && (options[offset] != DHCP_OPTION_END) && (offset < offset_max)) {
01344     u8_t op = options[offset];
01345     u8_t len;
01346     u8_t decode_len = 0;
01347     int decode_idx = -1;
01348     u16_t val_offset = offset + 2;
01349     /* len byte might be in the next pbuf */
01350     if (offset + 1 < q->len) {
01351       len = options[offset + 1];
01352     } else {
01353       len = (q->next != NULL ? ((u8_t*)q->next->payload)[0] : 0);
01354     }
01355     /* LWIP_DEBUGF(DHCP_DEBUG, ("msg_offset=%"U16_F", q->len=%"U16_F, msg_offset, q->len)); */
01356     decode_len = len;
01357     switch(op) {
01358       /* case(DHCP_OPTION_END): handled above */
01359       case(DHCP_OPTION_PAD):
01360         /* special option: no len encoded */
01361         decode_len = len = 0;
01362         /* will be increased below */
01363         offset--;
01364         break;
01365       case(DHCP_OPTION_SUBNET_MASK):
01366         LWIP_ASSERT("len == 4", len == 4);
01367         decode_idx = DHCP_OPTION_IDX_SUBNET_MASK;
01368         break;
01369       case(DHCP_OPTION_ROUTER):
01370         decode_len = 4; /* only copy the first given router */
01371         LWIP_ASSERT("len >= decode_len", len >= decode_len);
01372         decode_idx = DHCP_OPTION_IDX_ROUTER;
01373         break;
01374       case(DHCP_OPTION_DNS_SERVER):
01375         /* special case: there might be more than one server */
01376         LWIP_ASSERT("len % 4 == 0", len % 4 == 0);
01377         /* limit number of DNS servers */
01378         decode_len = LWIP_MIN(len, 4 * DNS_MAX_SERVERS);
01379         LWIP_ASSERT("len >= decode_len", len >= decode_len);
01380         decode_idx = DHCP_OPTION_IDX_DNS_SERVER;
01381         break;
01382       case(DHCP_OPTION_LEASE_TIME):
01383         LWIP_ASSERT("len == 4", len == 4);
01384         decode_idx = DHCP_OPTION_IDX_LEASE_TIME;
01385         break;
01386       case(DHCP_OPTION_OVERLOAD):
01387         LWIP_ASSERT("len == 1", len == 1);
01388         decode_idx = DHCP_OPTION_IDX_OVERLOAD;
01389         break;
01390       case(DHCP_OPTION_MESSAGE_TYPE):
01391         LWIP_ASSERT("len == 1", len == 1);
01392         decode_idx = DHCP_OPTION_IDX_MSG_TYPE;
01393         break;
01394       case(DHCP_OPTION_SERVER_ID):
01395         LWIP_ASSERT("len == 4", len == 4);
01396         decode_idx = DHCP_OPTION_IDX_SERVER_ID;
01397         break;
01398       case(DHCP_OPTION_T1):
01399         LWIP_ASSERT("len == 4", len == 4);
01400         decode_idx = DHCP_OPTION_IDX_T1;
01401         break;
01402       case(DHCP_OPTION_T2):
01403         LWIP_ASSERT("len == 4", len == 4);
01404         decode_idx = DHCP_OPTION_IDX_T2;
01405         break;
01406       default:
01407         decode_len = 0;
01408         LWIP_DEBUGF(DHCP_DEBUG, ("skipping option %"U16_F" in options\n", op));
01409         break;
01410     }
01411     offset += len + 2;
01412     if (decode_len > 0) {
01413       u32_t value = 0;
01414       u16_t copy_len;
01415 decode_next:
01416       LWIP_ASSERT("check decode_idx", decode_idx >= 0 && decode_idx < DHCP_OPTION_IDX_MAX);
01417       LWIP_ASSERT("option already decoded", !dhcp_option_given(dhcp, decode_idx));
01418       copy_len = LWIP_MIN(decode_len, 4);
01419       pbuf_copy_partial(q, &value, copy_len, val_offset);
01420       if (decode_len > 4) {
01421         /* decode more than one u32_t */
01422         LWIP_ASSERT("decode_len % 4 == 0", decode_len % 4 == 0);
01423         dhcp_got_option(dhcp, decode_idx);
01424         dhcp_set_option_value(dhcp, decode_idx, htonl(value));
01425         decode_len -= 4;
01426         val_offset += 4;
01427         decode_idx++;
01428         goto decode_next;
01429       } else if (decode_len == 4) {
01430         value = ntohl(value);
01431       } else {
01432         LWIP_ASSERT("invalid decode_len", decode_len == 1);
01433       }
01434         dhcp_got_option(dhcp, decode_idx);
01435         dhcp_set_option_value(dhcp, decode_idx, value);
01436     }
01437     if (offset >= q->len) {
01438       offset -= q->len;
01439       offset_max -= q->len;
01440       q = q->next;
01441       options = (u8_t*)q->payload;
01442     }
01443   }
01444   /* is this an overloaded message? */
01445   if (dhcp_option_given(dhcp, DHCP_OPTION_IDX_OVERLOAD)) {
01446     u32_t overload = dhcp_get_option_value(dhcp, DHCP_OPTION_IDX_OVERLOAD);
01447     dhcp_clear_option(dhcp, DHCP_OPTION_IDX_OVERLOAD);
01448     if (overload == DHCP_OVERLOAD_FILE) {
01449       parse_file_as_options = 1;
01450       LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE, ("overloaded file field\n"));
01451     } else if (overload == DHCP_OVERLOAD_SNAME) {
01452       parse_sname_as_options = 1;
01453       LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE, ("overloaded sname field\n"));
01454     } else if (overload == DHCP_OVERLOAD_SNAME_FILE) {
01455       parse_sname_as_options = 1;
01456       parse_file_as_options = 1;
01457       LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE, ("overloaded sname and file field\n"));
01458     } else {
01459       LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE, ("invalid overload option: %d\n", (int)overload));
01460     }
01461 #if LWIP_DHCP_BOOTP_FILE
01462     if (!parse_file_as_options) {
01463       /* only do this for ACK messages */
01464       if (dhcp_option_given(dhcp, DHCP_OPTION_IDX_MSG_TYPE) &&
01465         (dhcp_get_option_value(dhcp, DHCP_OPTION_IDX_MSG_TYPE) == DHCP_ACK))
01466       /* copy bootp file name, don't care for sname (server hostname) */
01467       pbuf_copy_partial(p, dhcp->boot_file_name, DHCP_FILE_LEN-1, DHCP_FILE_OFS);
01468       /* make sure the string is really NULL-terminated */
01469       dhcp->boot_file_name[DHCP_FILE_LEN-1] = 0;
01470     }
01471 #endif /* LWIP_DHCP_BOOTP_FILE */
01472   }
01473   if (parse_file_as_options) {
01474     /* if both are overloaded, parse file first and then sname (RFC 2131 ch. 4.1) */
01475     parse_file_as_options = 0;
01476     options_idx = DHCP_FILE_OFS;
01477     options_idx_max = DHCP_FILE_OFS + DHCP_FILE_LEN;
01478     goto again;
01479   } else if (parse_sname_as_options) {
01480     parse_sname_as_options = 0;
01481     options_idx = DHCP_SNAME_OFS;
01482     options_idx_max = DHCP_SNAME_OFS + DHCP_SNAME_LEN;
01483     goto again;
01484   }
01485   return ERR_OK;
01486 }
01487 
01488 /**
01489  * If an incoming DHCP message is in response to us, then trigger the state machine
01490  */
01491 static void
01492 dhcp_recv(void *arg, struct udp_pcb *pcb, struct pbuf *p, ip_addr_t *addr, u16_t port)
01493 {
01494   struct netif *netif = (struct netif *)arg;
01495   struct dhcp *dhcp = netif->dhcp;
01496   struct dhcp_msg *reply_msg = (struct dhcp_msg *)p->payload;
01497   u8_t msg_type;
01498   u8_t i;
01499   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,
01500     ip4_addr1_16(addr), ip4_addr2_16(addr), ip4_addr3_16(addr), ip4_addr4_16(addr), port));
01501   LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE, ("pbuf->len = %"U16_F"\n", p->len));
01502   LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE, ("pbuf->tot_len = %"U16_F"\n", p->tot_len));
01503   /* prevent warnings about unused arguments */
01504   LWIP_UNUSED_ARG(pcb);
01505   LWIP_UNUSED_ARG(addr);
01506   LWIP_UNUSED_ARG(port);
01507 
01508   LWIP_ASSERT("reply wasn't freed", dhcp->msg_in == NULL);
01509 
01510   if (p->len < DHCP_MIN_REPLY_LEN) {
01511     LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_LEVEL_WARNING, ("DHCP reply message or pbuf too short\n"));
01512     goto free_pbuf_and_return;
01513   }
01514 
01515   if (reply_msg->op != DHCP_BOOTREPLY) {
01516     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));
01517     goto free_pbuf_and_return;
01518   }
01519   /* iterate through hardware address and match against DHCP message */
01520   for (i = 0; i < netif->hwaddr_len; i++) {
01521     if (netif->hwaddr[i] != reply_msg->chaddr[i]) {
01522       LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_LEVEL_WARNING,
01523         ("netif->hwaddr[%"U16_F"]==%02"X16_F" != reply_msg->chaddr[%"U16_F"]==%02"X16_F"\n",
01524         (u16_t)i, (u16_t)netif->hwaddr[i], (u16_t)i, (u16_t)reply_msg->chaddr[i]));
01525       goto free_pbuf_and_return;
01526     }
01527   }
01528   /* match transaction ID against what we expected */
01529   if (ntohl(reply_msg->xid) != dhcp->xid) {
01530     LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_LEVEL_WARNING,
01531       ("transaction id mismatch reply_msg->xid(%"X32_F")!=dhcp->xid(%"X32_F")\n",ntohl(reply_msg->xid),dhcp->xid));
01532     goto free_pbuf_and_return;
01533   }
01534   /* option fields could be unfold? */
01535   if (dhcp_parse_reply(dhcp, p) != ERR_OK) {
01536     LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_LEVEL_SERIOUS,
01537       ("problem unfolding DHCP message - too short on memory?\n"));
01538     goto free_pbuf_and_return;
01539   }
01540 
01541   LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE, ("searching DHCP_OPTION_MESSAGE_TYPE\n"));
01542   /* obtain pointer to DHCP message type */
01543   if (!dhcp_option_given(dhcp, DHCP_OPTION_IDX_MSG_TYPE)) {
01544     LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_LEVEL_WARNING, ("DHCP_OPTION_MESSAGE_TYPE option not found\n"));
01545     goto free_pbuf_and_return;
01546   }
01547 
01548   /* read DHCP message type */
01549   msg_type = (u8_t)dhcp_get_option_value(dhcp, DHCP_OPTION_IDX_MSG_TYPE);
01550   /* message type is DHCP ACK? */
01551   if (msg_type == DHCP_ACK) {
01552     LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE, ("DHCP_ACK received\n"));
01553     /* in requesting state? */
01554     if (dhcp->state == DHCP_REQUESTING) {
01555       dhcp_handle_ack(netif);
01556 #if DHCP_DOES_ARP_CHECK
01557       /* check if the acknowledged lease address is already in use */
01558       dhcp_check(netif);
01559 #else
01560       /* bind interface to the acknowledged lease address */
01561       dhcp_bind(netif);
01562 #endif
01563     }
01564     /* already bound to the given lease address? */
01565     else if ((dhcp->state == DHCP_REBOOTING) || (dhcp->state == DHCP_REBINDING) || (dhcp->state == DHCP_RENEWING)) {
01566       dhcp_bind(netif);
01567     }
01568   }
01569   /* received a DHCP_NAK in appropriate state? */
01570   else if ((msg_type == DHCP_NAK) &&
01571     ((dhcp->state == DHCP_REBOOTING) || (dhcp->state == DHCP_REQUESTING) ||
01572      (dhcp->state == DHCP_REBINDING) || (dhcp->state == DHCP_RENEWING  ))) {
01573     LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE, ("DHCP_NAK received\n"));
01574     dhcp_handle_nak(netif);
01575   }
01576   /* received a DHCP_OFFER in DHCP_SELECTING state? */
01577   else if ((msg_type == DHCP_OFFER) && (dhcp->state == DHCP_SELECTING)) {
01578     LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE, ("DHCP_OFFER received in DHCP_SELECTING state\n"));
01579     dhcp->request_timeout = 0;
01580     /* remember offered lease */
01581     dhcp_handle_offer(netif);
01582   }
01583 free_pbuf_and_return:
01584   dhcp->msg_in = NULL;
01585   pbuf_free(p);
01586 }
01587 
01588 /**
01589  * Create a DHCP request, fill in common headers
01590  *
01591  * @param netif the netif under DHCP control
01592  * @param dhcp dhcp control struct
01593  * @param message_type message type of the request
01594  */
01595 static err_t
01596 dhcp_create_msg(struct netif *netif, struct dhcp *dhcp, u8_t message_type)
01597 {
01598   u16_t i;
01599 #ifndef DHCP_GLOBAL_XID
01600   /** default global transaction identifier starting value (easy to match
01601    *  with a packet analyser). We simply increment for each new request.
01602    *  Predefine DHCP_GLOBAL_XID to a better value or a function call to generate one
01603    *  at runtime, any supporting function prototypes can be defined in DHCP_GLOBAL_XID_HEADER */
01604   static u32_t xid = 0xABCD0000;
01605 #else
01606   static u32_t xid;
01607   static u8_t xid_initialised = 0;
01608   if (!xid_initialised) {
01609     xid = DHCP_GLOBAL_XID;
01610     xid_initialised = !xid_initialised;
01611   }
01612 #endif
01613   LWIP_ERROR("dhcp_create_msg: netif != NULL", (netif != NULL), return ERR_ARG;);
01614   LWIP_ERROR("dhcp_create_msg: dhcp != NULL", (dhcp != NULL), return ERR_VAL;);
01615   LWIP_ASSERT("dhcp_create_msg: dhcp->p_out == NULL", dhcp->p_out == NULL);
01616   LWIP_ASSERT("dhcp_create_msg: dhcp->msg_out == NULL", dhcp->msg_out == NULL);
01617   dhcp->p_out = pbuf_alloc(PBUF_TRANSPORT, sizeof(struct dhcp_msg), PBUF_RAM);
01618   if (dhcp->p_out == NULL) {
01619     LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_LEVEL_SERIOUS,
01620       ("dhcp_create_msg(): could not allocate pbuf\n"));
01621     return ERR_MEM;
01622   }
01623   LWIP_ASSERT("dhcp_create_msg: check that first pbuf can hold struct dhcp_msg",
01624            (dhcp->p_out->len >= sizeof(struct dhcp_msg)));
01625 
01626   /* reuse transaction identifier in retransmissions */
01627   if (dhcp->tries == 0) {
01628       xid++;
01629   }
01630   dhcp->xid = xid;
01631   LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE,
01632               ("transaction id xid(%"X32_F")\n", xid));
01633 
01634   dhcp->msg_out = (struct dhcp_msg *)dhcp->p_out->payload;
01635 
01636   dhcp->msg_out->op = DHCP_BOOTREQUEST;
01637   /* TODO: make link layer independent */
01638   dhcp->msg_out->htype = DHCP_HTYPE_ETH;
01639   dhcp->msg_out->hlen = netif->hwaddr_len;
01640   dhcp->msg_out->hops = 0;
01641   dhcp->msg_out->xid = htonl(dhcp->xid);
01642   dhcp->msg_out->secs = 0;
01643   /* we don't need the broadcast flag since we can receive unicast traffic
01644      before being fully configured! */
01645   dhcp->msg_out->flags = 0;
01646   ip_addr_set_zero(&dhcp->msg_out->ciaddr);
01647   /* set ciaddr to netif->ip_addr based on message_type and state */
01648   if ((message_type == DHCP_INFORM) || (message_type == DHCP_DECLINE) ||
01649       ((message_type == DHCP_REQUEST) && /* DHCP_BOUND not used for sending! */
01650        ((dhcp->state==DHCP_RENEWING) || dhcp->state==DHCP_REBINDING))) {
01651     ip_addr_copy(dhcp->msg_out->ciaddr, netif->ip_addr);
01652   }
01653   ip_addr_set_zero(&dhcp->msg_out->yiaddr);
01654   ip_addr_set_zero(&dhcp->msg_out->siaddr);
01655   ip_addr_set_zero(&dhcp->msg_out->giaddr);
01656   for (i = 0; i < DHCP_CHADDR_LEN; i++) {
01657     /* copy netif hardware address, pad with zeroes */
01658     dhcp->msg_out->chaddr[i] = (i < netif->hwaddr_len) ? netif->hwaddr[i] : 0/* pad byte*/;
01659   }
01660   for (i = 0; i < DHCP_SNAME_LEN; i++) {
01661     dhcp->msg_out->sname[i] = 0;
01662   }
01663   for (i = 0; i < DHCP_FILE_LEN; i++) {
01664     dhcp->msg_out->file[i] = 0;
01665   }
01666   dhcp->msg_out->cookie = htonl(DHCP_MAGIC_COOKIE);
01667   dhcp->options_out_len = 0;
01668   /* fill options field with an incrementing array (for debugging purposes) */
01669   for (i = 0; i < DHCP_OPTIONS_LEN; i++) {
01670     dhcp->msg_out->options[i] = (u8_t)i; /* for debugging only, no matter if truncated */
01671   }
01672   /* Add option MESSAGE_TYPE */
01673   dhcp_option(dhcp, DHCP_OPTION_MESSAGE_TYPE, DHCP_OPTION_MESSAGE_TYPE_LEN);
01674   dhcp_option_byte(dhcp, message_type);
01675   return ERR_OK;
01676 }
01677 
01678 /**
01679  * Free previously allocated memory used to send a DHCP request.
01680  *
01681  * @param dhcp the dhcp struct to free the request from
01682  */
01683 static void
01684 dhcp_delete_msg(struct dhcp *dhcp)
01685 {
01686   LWIP_ERROR("dhcp_delete_msg: dhcp != NULL", (dhcp != NULL), return;);
01687   LWIP_ASSERT("dhcp_delete_msg: dhcp->p_out != NULL", dhcp->p_out != NULL);
01688   LWIP_ASSERT("dhcp_delete_msg: dhcp->msg_out != NULL", dhcp->msg_out != NULL);
01689   if (dhcp->p_out != NULL) {
01690     pbuf_free(dhcp->p_out);
01691   }
01692   dhcp->p_out = NULL;
01693   dhcp->msg_out = NULL;
01694 }
01695 
01696 /**
01697  * Add a DHCP message trailer
01698  *
01699  * Adds the END option to the DHCP message, and if
01700  * necessary, up to three padding bytes.
01701  *
01702  * @param dhcp DHCP state structure
01703  */
01704 static void
01705 dhcp_option_trailer(struct dhcp *dhcp)
01706 {
01707   LWIP_ERROR("dhcp_option_trailer: dhcp != NULL", (dhcp != NULL), return;);
01708   LWIP_ASSERT("dhcp_option_trailer: dhcp->msg_out != NULL\n", dhcp->msg_out != NULL);
01709   LWIP_ASSERT("dhcp_option_trailer: dhcp->options_out_len < DHCP_OPTIONS_LEN\n", dhcp->options_out_len < DHCP_OPTIONS_LEN);
01710   dhcp->msg_out->options[dhcp->options_out_len++] = DHCP_OPTION_END;
01711   /* packet is too small, or not 4 byte aligned? */
01712   while ((dhcp->options_out_len < DHCP_MIN_OPTIONS_LEN) || (dhcp->options_out_len & 3)) {
01713     /* 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)); */
01714     LWIP_ASSERT("dhcp_option_trailer: dhcp->options_out_len < DHCP_OPTIONS_LEN\n", dhcp->options_out_len < DHCP_OPTIONS_LEN);
01715     /* add a fill/padding byte */
01716     dhcp->msg_out->options[dhcp->options_out_len++] = 0;
01717   }
01718 }
01719 
01720 #endif /* LWIP_DHCP */