/** * @file * Dynamic Host Configuration Protocol client * *//* * * Copyright (c) 2001-2004 Leon Woestenberg <leon.woestenberg@gmx.net> * Copyright (c) 2001-2004 Axon Digital Design B.V., The Netherlands. * All rights reserved. * * Redistribution and use in source and binary forms, with or without modification, * are permitted provided that the following conditions are met: * * 1. Redistributions of source code must retain the above copyright notice, * this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright notice, * this list of conditions and the following disclaimer in the documentation * and/or other materials provided with the distribution. * 3. The name of the author may not be used to endorse or promote products * derived from this software without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY * OF SUCH DAMAGE. * * This file is a contribution to the lwIP TCP/IP stack. * The Swedish Institute of Computer Science and Adam Dunkels * are specifically granted permission to redistribute this * source code. * * Author: Leon Woestenberg <leon.woestenberg@gmx.net> * * This is a DHCP client for the lwIP TCP/IP stack. It aims to conform * with RFC 2131 and RFC 2132. * * TODO: * - Support for interfaces other than Ethernet (SLIP, PPP, ...) * * Please coordinate changes and requests with Leon Woestenberg * <leon.woestenberg@gmx.net> * * Integration with your code: * * In lwip/dhcp.h * #define DHCP_COARSE_TIMER_SECS (recommended 60 which is a minute) * #define DHCP_FINE_TIMER_MSECS (recommended 500 which equals TCP coarse timer) * * Then have your application call dhcp_coarse_tmr() and * dhcp_fine_tmr() on the defined intervals. * * dhcp_start(struct netif *netif); * starts a DHCP client instance which configures the interface by * obtaining an IP address lease and maintaining it. * * Use dhcp_release(netif) to end the lease and use dhcp_stop(netif) * to remove the DHCP client. * */#include "lwip/opt.h"#if LWIP_DHCP /* don't build if not configured for use in lwipopts.h */#include "lwip/stats.h"#include "lwip/mem.h"#include "lwip/udp.h"#include "lwip/ip_addr.h"#include "lwip/netif.h"#include "lwip/def.h"#include "lwip/sys.h"#include "lwip/dhcp.h"#include "lwip/autoip.h"#include "lwip/dns.h"#include "netif/etharp.h"#include <string.h>/** Default for DHCP_GLOBAL_XID is 0xABCD0000 * This can be changed by defining DHCP_GLOBAL_XID and DHCP_GLOBAL_XID_HEADER, e.g. * #define DHCP_GLOBAL_XID_HEADER "stdlib.h" * #define DHCP_GLOBAL_XID rand() */#ifdef DHCP_GLOBAL_XID_HEADER#include DHCP_GLOBAL_XID_HEADER /* include optional starting XID generation prototypes */#endif/** DHCP_OPTION_MAX_MSG_SIZE is set to the MTU * MTU is checked to be big enough in dhcp_start */#define DHCP_MAX_MSG_LEN(netif) (netif->mtu)#define DHCP_MAX_MSG_LEN_MIN_REQUIRED 576/** Minimum length for reply before packet is parsed */#define DHCP_MIN_REPLY_LEN 44#define REBOOT_TRIES 2/** Option handling: options are parsed in dhcp_parse_reply * and saved in an array where other functions can load them from. * This might be moved into the struct dhcp (not necessarily since * lwIP is single-threaded and the array is only used while in recv * callback). */#define DHCP_OPTION_IDX_OVERLOAD 0#define DHCP_OPTION_IDX_MSG_TYPE 1#define DHCP_OPTION_IDX_SERVER_ID 2#define DHCP_OPTION_IDX_LEASE_TIME 3#define DHCP_OPTION_IDX_T1 4#define DHCP_OPTION_IDX_T2 5#define DHCP_OPTION_IDX_SUBNET_MASK 6#define DHCP_OPTION_IDX_ROUTER 7#define DHCP_OPTION_IDX_DNS_SERVER8#define DHCP_OPTION_IDX_MAX (DHCP_OPTION_IDX_DNS_SERVER + DNS_MAX_SERVERS)/** Holds the decoded option values, only valid while in dhcp_recv. @todo: move this into struct dhcp? */u32_t dhcp_rx_options_val[DHCP_OPTION_IDX_MAX];/** Holds a flag which option was received and is contained in dhcp_rx_options_val, only valid while in dhcp_recv. @todo: move this into struct dhcp? */u8_t dhcp_rx_options_given[DHCP_OPTION_IDX_MAX];#define dhcp_option_given(dhcp, idx) (dhcp_rx_options_given[idx] != 0)#define dhcp_got_option(dhcp, idx) (dhcp_rx_options_given[idx] = 1)#define dhcp_clear_option(dhcp, idx) (dhcp_rx_options_given[idx] = 0)#define dhcp_clear_all_options(dhcp) (memset(dhcp_rx_options_given, 0, sizeof(dhcp_rx_options_given)))#define dhcp_get_option_value(dhcp, idx) (dhcp_rx_options_val[idx])#define dhcp_set_option_value(dhcp, idx, val) (dhcp_rx_options_val[idx] = (val))/* DHCP client state machine functions */static err_t dhcp_discover(struct netif *netif);static err_t dhcp_select(struct netif *netif);static void dhcp_bind(struct netif *netif);#if DHCP_DOES_ARP_CHECKstatic err_t dhcp_decline(struct netif *netif);#endif /* DHCP_DOES_ARP_CHECK */static err_t dhcp_rebind(struct netif *netif);static err_t dhcp_reboot(struct netif *netif);static void dhcp_set_state(struct dhcp *dhcp, u8_t new_state);/* receive, unfold, parse and free incoming messages */static void dhcp_recv(void *arg, struct udp_pcb *pcb, struct pbuf *p, ip_addr_t *addr, u16_t port);/* set the DHCP timers */static void dhcp_timeout(struct netif *netif);static void dhcp_t1_timeout(struct netif *netif);static void dhcp_t2_timeout(struct netif *netif);/* build outgoing messages *//* create a DHCP message, fill in common headers */static err_t dhcp_create_msg(struct netif *netif, struct dhcp *dhcp, u8_t message_type);/* free a DHCP request */static void dhcp_delete_msg(struct dhcp *dhcp);/* add a DHCP option (type, then length in bytes) */static void dhcp_option(struct dhcp *dhcp, u8_t option_type, u8_t option_len);/* add option values */static void dhcp_option_byte(struct dhcp *dhcp, u8_t value);static void dhcp_option_short(struct dhcp *dhcp, u16_t value);static void dhcp_option_long(struct dhcp *dhcp, u32_t value);/* always add the DHCP options trailer to end and pad */static void dhcp_option_trailer(struct dhcp *dhcp);/** * Back-off the DHCP client (because of a received NAK response). * * Back-off the DHCP client because of a received NAK. Receiving a * NAK means the client asked for something non-sensible, for * example when it tries to renew a lease obtained on another network. * * We clear any existing set IP address and restart DHCP negotiation * afresh (as per RFC2131 3.2.3). * * @param netif the netif under DHCP control */static voiddhcp_handle_nak(struct netif *netif){ struct dhcp *dhcp = netif->dhcp; LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE, ("dhcp_handle_nak(netif=%p) %c%c%"U16_F"\n", (void*)netif, netif->name[0], netif->name[1], (u16_t)netif->num)); /* Set the interface down since the address must no longer be used, as per RFC2131 */ netif_set_down(netif); /* remove IP address from interface */ netif_set_ipaddr(netif, IP_ADDR_ANY); netif_set_gw(netif, IP_ADDR_ANY); netif_set_netmask(netif, IP_ADDR_ANY); /* Change to a defined state */ dhcp_set_state(dhcp, DHCP_BACKING_OFF); /* We can immediately restart discovery */ dhcp_discover(netif);}#if DHCP_DOES_ARP_CHECK/** * Checks if the offered IP address is already in use. * * It does so by sending an ARP request for the offered address and * entering CHECKING state. If no ARP reply is received within a small * interval, the address is assumed to be free for use by us. * * @param netif the netif under DHCP control */static voiddhcp_check(struct netif *netif){ struct dhcp *dhcp = netif->dhcp; err_t result; u16_t msecs; LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE, ("dhcp_check(netif=%p) %c%c\n", (void *)netif, (s16_t)netif->name[0], (s16_t)netif->name[1])); dhcp_set_state(dhcp, DHCP_CHECKING); /* create an ARP query for the offered IP address, expecting that no host responds, as the IP address should not be in use. */ result = etharp_query(netif, &dhcp->offered_ip_addr, NULL); if (result != ERR_OK) { LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_LEVEL_WARNING, ("dhcp_check: could not perform ARP query\n")); } dhcp->tries++; msecs = 500; dhcp->request_timeout = (msecs + DHCP_FINE_TIMER_MSECS - 1) / DHCP_FINE_TIMER_MSECS; LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE, ("dhcp_check(): set request timeout %"U16_F" msecs\n", msecs));}#endif /* DHCP_DOES_ARP_CHECK *//** * Remember the configuration offered by a DHCP server. * * @param netif the netif under DHCP control */static voiddhcp_handle_offer(struct netif *netif){ struct dhcp *dhcp = netif->dhcp; LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE, ("dhcp_handle_offer(netif=%p) %c%c%"U16_F"\n", (void*)netif, netif->name[0], netif->name[1], (u16_t)netif->num)); /* obtain the server address */ if (dhcp_option_given(dhcp, DHCP_OPTION_IDX_SERVER_ID)) { ip4_addr_set_u32(&dhcp->server_ip_addr, htonl(dhcp_get_option_value(dhcp, DHCP_OPTION_IDX_SERVER_ID))); LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_STATE, ("dhcp_handle_offer(): server 0x%08"X32_F"\n", ip4_addr_get_u32(&dhcp->server_ip_addr))); /* remember offered address */ ip_addr_copy(dhcp->offered_ip_addr, dhcp->msg_in->yiaddr); LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_STATE, ("dhcp_handle_offer(): offer for 0x%08"X32_F"\n", ip4_addr_get_u32(&dhcp->offered_ip_addr))); dhcp_select(netif); } else { LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_LEVEL_SERIOUS, ("dhcp_handle_offer(netif=%p) did not get server ID!\n", (void*)netif)); }}/** * Select a DHCP server offer out of all offers. * * Simply select the first offer received. * * @param netif the netif under DHCP control * @return lwIP specific error (see error.h) */static err_tdhcp_select(struct netif *netif){ struct dhcp *dhcp = netif->dhcp; err_t result; u16_t msecs; 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)); dhcp_set_state(dhcp, DHCP_REQUESTING); /* create and initialize the DHCP message header */ result = dhcp_create_msg(netif, dhcp, DHCP_REQUEST); if (result == ERR_OK) { dhcp_option(dhcp, DHCP_OPTION_MAX_MSG_SIZE, DHCP_OPTION_MAX_MSG_SIZE_LEN); dhcp_option_short(dhcp, DHCP_MAX_MSG_LEN(netif)); /* MUST request the offered IP address */ dhcp_option(dhcp, DHCP_OPTION_REQUESTED_IP, 4); dhcp_option_long(dhcp, ntohl(ip4_addr_get_u32(&dhcp->offered_ip_addr))); dhcp_option(dhcp, DHCP_OPTION_SERVER_ID, 4); dhcp_option_long(dhcp, ntohl(ip4_addr_get_u32(&dhcp->server_ip_addr))); dhcp_option(dhcp, DHCP_OPTION_PARAMETER_REQUEST_LIST, 4/*num options*/); dhcp_option_byte(dhcp, DHCP_OPTION_SUBNET_MASK); dhcp_option_byte(dhcp, DHCP_OPTION_ROUTER); dhcp_option_byte(dhcp, DHCP_OPTION_BROADCAST); dhcp_option_byte(dhcp, DHCP_OPTION_DNS_SERVER);#if LWIP_NETIF_HOSTNAME if (netif->hostname != NULL) { const char *p = (const char*)netif->hostname; u8_t namelen = (u8_t)strlen(p); if (namelen > 0) { LWIP_ASSERT("DHCP: hostname is too long!", namelen < 255); dhcp_option(dhcp, DHCP_OPTION_HOSTNAME, namelen); while (*p) { dhcp_option_byte(dhcp, *p++); } } }#endif /* LWIP_NETIF_HOSTNAME */ dhcp_option_trailer(dhcp); /* shrink the pbuf to the actual content length */ pbuf_realloc(dhcp->p_out, sizeof(struct dhcp_msg) - DHCP_OPTIONS_LEN + dhcp->options_out_len); /* send broadcast to any DHCP server */ udp_sendto_if(dhcp->pcb, dhcp->p_out, IP_ADDR_BROADCAST, DHCP_SERVER_PORT, netif); dhcp_delete_msg(dhcp); LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE, ("dhcp_select: REQUESTING\n")); } else { LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_LEVEL_WARNING, ("dhcp_select: could not allocate DHCP request\n")); } dhcp->tries++; msecs = (dhcp->tries < 6 ? 1 << dhcp->tries : 60) * 1000; dhcp->request_timeout = (msecs + DHCP_FINE_TIMER_MSECS - 1) / DHCP_FINE_TIMER_MSECS; LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_STATE, ("dhcp_select(): set request timeout %"U16_F" msecs\n", msecs)); return result;}/** * The DHCP timer that checks for lease renewal/rebind timeouts. */voiddhcp_coarse_tmr(){ struct netif *netif = netif_list; LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE, ("dhcp_coarse_tmr()\n")); /* iterate through all network interfaces */ while (netif != NULL) { /* only act on DHCP configured interfaces */ if (netif->dhcp != NULL) { /* timer is active (non zero), and triggers (zeroes) now? */ if (netif->dhcp->t2_timeout-- == 1) { LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE, ("dhcp_coarse_tmr(): t2 timeout\n")); /* this clients' rebind timeout triggered */ dhcp_t2_timeout(netif); /* timer is active (non zero), and triggers (zeroes) now */ } else if (netif->dhcp->t1_timeout-- == 1) { LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE, ("dhcp_coarse_tmr(): t1 timeout\n")); /* this clients' renewal timeout triggered */ dhcp_t1_timeout(netif); } } /* proceed to next netif */ netif = netif->next; }}/** * DHCP transaction timeout handling * * A DHCP server is expected to respond within a short period of time. * This timer checks whether an outstanding DHCP request is timed out. */voiddhcp_fine_tmr(){ struct netif *netif = netif_list; /* loop through netif's */ while (netif != NULL) { /* only act on DHCP configured interfaces */ if (netif->dhcp != NULL) { /* timer is active (non zero), and is about to trigger now */ if (netif->dhcp->request_timeout > 1) { netif->dhcp->request_timeout--; } else if (netif->dhcp->request_timeout == 1) { netif->dhcp->request_timeout--; /* { netif->dhcp->request_timeout == 0 } */ LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE, ("dhcp_fine_tmr(): request timeout\n")); /* this client's request timeout triggered */ dhcp_timeout(netif); } } /* proceed to next network interface */ netif = netif->next; }}/** * A DHCP negotiation transaction, or ARP request, has timed out. * * The timer that was started with the DHCP or ARP request has * timed out, indicating no response was received in time. * * @param netif the netif under DHCP control */static voiddhcp_timeout(struct netif *netif){ struct dhcp *dhcp = netif->dhcp; LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE, ("dhcp_timeout()\n")); /* back-off period has passed, or server selection timed out */ if ((dhcp->state == DHCP_BACKING_OFF) || (dhcp->state == DHCP_SELECTING)) { LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE, ("dhcp_timeout(): restarting discovery\n")); dhcp_discover(netif); /* receiving the requested lease timed out */ } else if (dhcp->state == DHCP_REQUESTING) { LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE, ("dhcp_timeout(): REQUESTING, DHCP request timed out\n")); if (dhcp->tries <= 5) { dhcp_select(netif); } else { LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE, ("dhcp_timeout(): REQUESTING, releasing, restarting\n")); dhcp_release(netif); dhcp_discover(netif); }#if DHCP_DOES_ARP_CHECK /* received no ARP reply for the offered address (which is good) */ } else if (dhcp->state == DHCP_CHECKING) { LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE, ("dhcp_timeout(): CHECKING, ARP request timed out\n")); if (dhcp->tries <= 1) { dhcp_check(netif); /* no ARP replies on the offered address, looks like the IP address is indeed free */ } else { /* bind the interface to the offered address */ dhcp_bind(netif); }#endif /* DHCP_DOES_ARP_CHECK */ } /* did not get response to renew request? */ else if (dhcp->state == DHCP_RENEWING) { LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE, ("dhcp_timeout(): RENEWING, DHCP request timed out\n")); /* just retry renewal */ /* note that the rebind timer will eventually time-out if renew does not work */ dhcp_renew(netif); /* did not get response to rebind request? */ } else if (dhcp->state == DHCP_REBINDING) { LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE, ("dhcp_timeout(): REBINDING, DHCP request timed out\n")); if (dhcp->tries <= 8) { dhcp_rebind(netif); } else { LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE, ("dhcp_timeout(): RELEASING, DISCOVERING\n")); dhcp_release(netif); dhcp_discover(netif); } } else if (dhcp->state == DHCP_REBOOTING) { if (dhcp->tries < REBOOT_TRIES) { dhcp_reboot(netif); } else { dhcp_discover(netif); } }}/** * The renewal period has timed out. * * @param netif the netif under DHCP control */static voiddhcp_t1_timeout(struct netif *netif){ struct dhcp *dhcp = netif->dhcp; LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_STATE, ("dhcp_t1_timeout()\n")); if ((dhcp->state == DHCP_REQUESTING) || (dhcp->state == DHCP_BOUND) || (dhcp->state == DHCP_RENEWING)) { /* just retry to renew - note that the rebind timer (t2) will * eventually time-out if renew tries fail. */ LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE, ("dhcp_t1_timeout(): must renew\n")); /* This slightly different to RFC2131: DHCPREQUEST will be sent from state DHCP_RENEWING, not DHCP_BOUND */ dhcp_renew(netif); }}/** * The rebind period has timed out. * * @param netif the netif under DHCP control */static voiddhcp_t2_timeout(struct netif *netif){ struct dhcp *dhcp = netif->dhcp; LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE, ("dhcp_t2_timeout()\n")); if ((dhcp->state == DHCP_REQUESTING) || (dhcp->state == DHCP_BOUND) || (dhcp->state == DHCP_RENEWING)) { /* just retry to rebind */ LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE, ("dhcp_t2_timeout(): must rebind\n")); /* This slightly different to RFC2131: DHCPREQUEST will be sent from state DHCP_REBINDING, not DHCP_BOUND */ dhcp_rebind(netif); }}/** * Handle a DHCP ACK packet * * @param netif the netif under DHCP control */static voiddhcp_handle_ack(struct netif *netif){ struct dhcp *dhcp = netif->dhcp;#if LWIP_DNS u8_t n;#endif /* LWIP_DNS */ /* clear options we might not get from the ACK */ ip_addr_set_zero(&dhcp->offered_sn_mask); ip_addr_set_zero(&dhcp->offered_gw_addr);#if LWIP_DHCP_BOOTP_FILE ip_addr_set_zero(&dhcp->offered_si_addr);#endif /* LWIP_DHCP_BOOTP_FILE */ /* lease time given? */ if (dhcp_option_given(dhcp, DHCP_OPTION_IDX_LEASE_TIME)) { /* remember offered lease time */ dhcp->offered_t0_lease = dhcp_get_option_value(dhcp, DHCP_OPTION_IDX_LEASE_TIME); } /* renewal period given? */ if (dhcp_option_given(dhcp, DHCP_OPTION_IDX_T1)) { /* remember given renewal period */ dhcp->offered_t1_renew = dhcp_get_option_value(dhcp, DHCP_OPTION_IDX_T1); } else { /* calculate safe periods for renewal */ dhcp->offered_t1_renew = dhcp->offered_t0_lease / 2; } /* renewal period given? */ if (dhcp_option_given(dhcp, DHCP_OPTION_IDX_T2)) { /* remember given rebind period */ dhcp->offered_t2_rebind = dhcp_get_option_value(dhcp, DHCP_OPTION_IDX_T2); } else { /* calculate safe periods for rebinding */ dhcp->offered_t2_rebind = dhcp->offered_t0_lease; } /* (y)our internet address */ ip_addr_copy(dhcp->offered_ip_addr, dhcp->msg_in->yiaddr);#if LWIP_DHCP_BOOTP_FILE /* copy boot server address, boot file name copied in dhcp_parse_reply if not overloaded */ ip_addr_copy(dhcp->offered_si_addr, dhcp->msg_in->siaddr);#endif /* LWIP_DHCP_BOOTP_FILE */ /* subnet mask given? */ if (dhcp_option_given(dhcp, DHCP_OPTION_IDX_SUBNET_MASK)) { /* remember given subnet mask */ ip4_addr_set_u32(&dhcp->offered_sn_mask, htonl(dhcp_get_option_value(dhcp, DHCP_OPTION_IDX_SUBNET_MASK))); dhcp->subnet_mask_given = 1; } else { dhcp->subnet_mask_given = 0; } /* gateway router */ if (dhcp_option_given(dhcp, DHCP_OPTION_IDX_ROUTER)) { ip4_addr_set_u32(&dhcp->offered_gw_addr, htonl(dhcp_get_option_value(dhcp, DHCP_OPTION_IDX_ROUTER))); } #if LWIP_DNS /* DNS servers */ n = 0; while(dhcp_option_given(dhcp, DHCP_OPTION_IDX_DNS_SERVER + n) && (n < DNS_MAX_SERVERS)) { ip_addr_t dns_addr; ip4_addr_set_u32(&dns_addr, htonl(dhcp_get_option_value(dhcp, DHCP_OPTION_IDX_DNS_SERVER + n))); dns_setserver(n, &dns_addr); n++; }#endif /* LWIP_DNS */}/** Set a statically allocated struct dhcp to work with. * Using this prevents dhcp_start to allocate it using mem_malloc. * * @param netif the netif for which to set the struct dhcp * @param dhcp (uninitialised) dhcp struct allocated by the application */voiddhcp_set_struct(struct netif *netif, struct dhcp *dhcp){ LWIP_ASSERT("netif != NULL", netif != NULL); LWIP_ASSERT("dhcp != NULL", dhcp != NULL); LWIP_ASSERT("netif already has a struct dhcp set", netif->dhcp == NULL); /* clear data structure */ memset(dhcp, 0, sizeof(struct dhcp)); /* dhcp_set_state(&dhcp, DHCP_OFF); */ netif->dhcp = dhcp;}/** Removes a struct dhcp from a netif. * * ATTENTION: Only use this when not using dhcp_set_struct() to allocate the * struct dhcp since the memory is passed back to the heap. * * @param netif the netif from which to remove the struct dhcp */void dhcp_cleanup(struct netif *netif){ LWIP_ASSERT("netif != NULL", netif != NULL); if (netif->dhcp != NULL) { mem_free(netif->dhcp); netif->dhcp = NULL; }}/** * Start DHCP negotiation for a network interface. * * If no DHCP client instance was attached to this interface, * a new client is created first. If a DHCP client instance * was already present, it restarts negotiation. * * @param netif The lwIP network interface * @return lwIP error code * - ERR_OK - No error * - ERR_MEM - Out of memory */err_tdhcp_start(struct netif *netif){ struct dhcp *dhcp; err_t result = ERR_OK; LWIP_ERROR("netif != NULL", (netif != NULL), return ERR_ARG;); dhcp = netif->dhcp; 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)); /* Remove the flag that says this netif is handled by DHCP, it is set when we succeeded starting. */ netif->flags &= ~NETIF_FLAG_DHCP; /* check hwtype of the netif */ if ((netif->flags & NETIF_FLAG_ETHARP) == 0) { LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE, ("dhcp_start(): No ETHARP netif\n")); return ERR_ARG; } /* check MTU of the netif */ if (netif->mtu < DHCP_MAX_MSG_LEN_MIN_REQUIRED) { LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE, ("dhcp_start(): Cannot use this netif with DHCP: MTU is too small\n")); return ERR_MEM; } /* no DHCP client attached yet? */ if (dhcp == NULL) { LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE, ("dhcp_start(): starting new DHCP client\n")); dhcp = (struct dhcp *)mem_malloc(sizeof(struct dhcp)); if (dhcp == NULL) { LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE, ("dhcp_start(): could not allocate dhcp\n")); return ERR_MEM; } /* store this dhcp client in the netif */ netif->dhcp = dhcp; LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE, ("dhcp_start(): allocated dhcp")); /* already has DHCP client attached */ } else { LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE, ("dhcp_start(): restarting DHCP configuration\n")); if (dhcp->pcb != NULL) { udp_remove(dhcp->pcb); } LWIP_ASSERT("pbuf p_out wasn't freed", dhcp->p_out == NULL); LWIP_ASSERT("reply wasn't freed", dhcp->msg_in == NULL ); } /* clear data structure */ memset(dhcp, 0, sizeof(struct dhcp)); /* dhcp_set_state(&dhcp, DHCP_OFF); */ /* allocate UDP PCB */ dhcp->pcb = udp_new(); if (dhcp->pcb == NULL) { LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE, ("dhcp_start(): could not obtain pcb\n")); return ERR_MEM; } dhcp->pcb->so_options |= SOF_BROADCAST; /* set up local and remote port for the pcb */ udp_bind(dhcp->pcb, IP_ADDR_ANY, DHCP_CLIENT_PORT); udp_connect(dhcp->pcb, IP_ADDR_ANY, DHCP_SERVER_PORT); /* set up the recv callback and argument */ udp_recv(dhcp->pcb, dhcp_recv, netif); LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE, ("dhcp_start(): starting DHCP configuration\n")); /* (re)start the DHCP negotiation */ result = dhcp_discover(netif); if (result != ERR_OK) { /* free resources allocated above */ dhcp_stop(netif); return ERR_MEM; } /* Set the flag that says this netif is handled by DHCP. */ netif->flags |= NETIF_FLAG_DHCP; return result;}/** * Inform a DHCP server of our manual configuration. * * This informs DHCP servers of our fixed IP address configuration * by sending an INFORM message. It does not involve DHCP address * configuration, it is just here to be nice to the network. * * @param netif The lwIP network interface */voiddhcp_inform(struct netif *netif){ struct dhcp dhcp; err_t result = ERR_OK; struct udp_pcb *pcb; LWIP_ERROR("netif != NULL", (netif != NULL), return;); memset(&dhcp, 0, sizeof(struct dhcp)); dhcp_set_state(&dhcp, DHCP_INFORM); if ((netif->dhcp != NULL) && (netif->dhcp->pcb != NULL)) { /* re-use existing pcb */ pcb = netif->dhcp->pcb; } else { pcb = udp_new(); if (pcb == NULL) { LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_LEVEL_SERIOUS, ("dhcp_inform(): could not obtain pcb")); return; } dhcp.pcb = pcb; dhcp.pcb->so_options |= SOF_BROADCAST; udp_bind(dhcp.pcb, IP_ADDR_ANY, DHCP_CLIENT_PORT); LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE, ("dhcp_inform(): created new udp pcb\n")); } /* create and initialize the DHCP message header */ result = dhcp_create_msg(netif, &dhcp, DHCP_INFORM); if (result == ERR_OK) { dhcp_option(&dhcp, DHCP_OPTION_MAX_MSG_SIZE, DHCP_OPTION_MAX_MSG_SIZE_LEN); dhcp_option_short(&dhcp, DHCP_MAX_MSG_LEN(netif)); dhcp_option_trailer(&dhcp); pbuf_realloc(dhcp.p_out, sizeof(struct dhcp_msg) - DHCP_OPTIONS_LEN + dhcp.options_out_len); LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE, ("dhcp_inform: INFORMING\n")); udp_sendto_if(pcb, dhcp.p_out, IP_ADDR_BROADCAST, DHCP_SERVER_PORT, netif); dhcp_delete_msg(&dhcp); } else { LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_LEVEL_SERIOUS, ("dhcp_inform: could not allocate DHCP request\n")); } if (dhcp.pcb != NULL) { /* otherwise, the existing pcb was used */ udp_remove(dhcp.pcb); }}/** Handle a possible change in the network configuration. * * This enters the REBOOTING state to verify that the currently bound * address is still valid. */voiddhcp_network_changed(struct netif *netif){ struct dhcp *dhcp = netif->dhcp; if (!dhcp) return; switch (dhcp->state) { case DHCP_REBINDING: case DHCP_RENEWING: case DHCP_BOUND: case DHCP_REBOOTING: netif_set_down(netif); dhcp->tries = 0; dhcp_reboot(netif); break; case DHCP_OFF: /* stay off */ break; default: dhcp->tries = 0;#if LWIP_DHCP_AUTOIP_COOP if(dhcp->autoip_coop_state == DHCP_AUTOIP_COOP_STATE_ON) { autoip_stop(netif); dhcp->autoip_coop_state = DHCP_AUTOIP_COOP_STATE_OFF; }#endif /* LWIP_DHCP_AUTOIP_COOP */ dhcp_discover(netif); break; }}#if DHCP_DOES_ARP_CHECK/** * Match an ARP reply with the offered IP address. * * @param netif the network interface on which the reply was received * @param addr The IP address we received a reply from */void dhcp_arp_reply(struct netif *netif, ip_addr_t *addr){ LWIP_ERROR("netif != NULL", (netif != NULL), return;); LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE, ("dhcp_arp_reply()\n")); /* is a DHCP client doing an ARP check? */ if ((netif->dhcp != NULL) && (netif->dhcp->state == DHCP_CHECKING)) { LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE, ("dhcp_arp_reply(): CHECKING, arp reply for 0x%08"X32_F"\n", ip4_addr_get_u32(addr))); /* did a host respond with the address we were offered by the DHCP server? */ if (ip_addr_cmp(addr, &netif->dhcp->offered_ip_addr)) { /* we will not accept the offered address */ LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE | LWIP_DBG_LEVEL_WARNING, ("dhcp_arp_reply(): arp reply matched with offered address, declining\n")); dhcp_decline(netif); } }}/** * Decline an offered lease. * * Tell the DHCP server we do not accept the offered address. * One reason to decline the lease is when we find out the address * is already in use by another host (through ARP). * * @param netif the netif under DHCP control */static err_tdhcp_decline(struct netif *netif){ struct dhcp *dhcp = netif->dhcp; err_t result = ERR_OK; u16_t msecs; LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE, ("dhcp_decline()\n")); dhcp_set_state(dhcp, DHCP_BACKING_OFF); /* create and initialize the DHCP message header */ result = dhcp_create_msg(netif, dhcp, DHCP_DECLINE); if (result == ERR_OK) { dhcp_option(dhcp, DHCP_OPTION_REQUESTED_IP, 4); dhcp_option_long(dhcp, ntohl(ip4_addr_get_u32(&dhcp->offered_ip_addr))); dhcp_option_trailer(dhcp); /* resize pbuf to reflect true size of options */ pbuf_realloc(dhcp->p_out, sizeof(struct dhcp_msg) - DHCP_OPTIONS_LEN + dhcp->options_out_len); /* per section 4.4.4, broadcast DECLINE messages */ udp_sendto_if(dhcp->pcb, dhcp->p_out, IP_ADDR_BROADCAST, DHCP_SERVER_PORT, netif); dhcp_delete_msg(dhcp); LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE, ("dhcp_decline: BACKING OFF\n")); } else { LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_LEVEL_SERIOUS, ("dhcp_decline: could not allocate DHCP request\n")); } dhcp->tries++; msecs = 10*1000; dhcp->request_timeout = (msecs + DHCP_FINE_TIMER_MSECS - 1) / DHCP_FINE_TIMER_MSECS; LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE, ("dhcp_decline(): set request timeout %"U16_F" msecs\n", msecs)); return result;}#endif /* DHCP_DOES_ARP_CHECK *//** * Start the DHCP process, discover a DHCP server. * * @param netif the netif under DHCP control */static err_tdhcp_discover(struct netif *netif){ struct dhcp *dhcp = netif->dhcp; err_t result = ERR_OK; u16_t msecs; LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE, ("dhcp_discover()\n")); ip_addr_set_any(&dhcp->offered_ip_addr); dhcp_set_state(dhcp, DHCP_SELECTING); /* create and initialize the DHCP message header */ result = dhcp_create_msg(netif, dhcp, DHCP_DISCOVER); if (result == ERR_OK) { LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE, ("dhcp_discover: making request\n")); dhcp_option(dhcp, DHCP_OPTION_MAX_MSG_SIZE, DHCP_OPTION_MAX_MSG_SIZE_LEN); dhcp_option_short(dhcp, DHCP_MAX_MSG_LEN(netif)); dhcp_option(dhcp, DHCP_OPTION_PARAMETER_REQUEST_LIST, 4/*num options*/); dhcp_option_byte(dhcp, DHCP_OPTION_SUBNET_MASK); dhcp_option_byte(dhcp, DHCP_OPTION_ROUTER); dhcp_option_byte(dhcp, DHCP_OPTION_BROADCAST); dhcp_option_byte(dhcp, DHCP_OPTION_DNS_SERVER); dhcp_option_trailer(dhcp); LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE, ("dhcp_discover: realloc()ing\n")); pbuf_realloc(dhcp->p_out, sizeof(struct dhcp_msg) - DHCP_OPTIONS_LEN + dhcp->options_out_len); LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE, ("dhcp_discover: sendto(DISCOVER, IP_ADDR_BROADCAST, DHCP_SERVER_PORT)\n")); udp_sendto_if(dhcp->pcb, dhcp->p_out, IP_ADDR_BROADCAST, DHCP_SERVER_PORT, netif); LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE, ("dhcp_discover: deleting()ing\n")); dhcp_delete_msg(dhcp); LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE, ("dhcp_discover: SELECTING\n")); } else { LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_LEVEL_SERIOUS, ("dhcp_discover: could not allocate DHCP request\n")); } dhcp->tries++;#if LWIP_DHCP_AUTOIP_COOP if(dhcp->tries >= LWIP_DHCP_AUTOIP_COOP_TRIES && dhcp->autoip_coop_state == DHCP_AUTOIP_COOP_STATE_OFF) { dhcp->autoip_coop_state = DHCP_AUTOIP_COOP_STATE_ON; autoip_start(netif); }#endif /* LWIP_DHCP_AUTOIP_COOP */ msecs = (dhcp->tries < 6 ? 1 << dhcp->tries : 60) * 1000; dhcp->request_timeout = (msecs + DHCP_FINE_TIMER_MSECS - 1) / DHCP_FINE_TIMER_MSECS; LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE, ("dhcp_discover(): set request timeout %"U16_F" msecs\n", msecs)); return result;}/** * Bind the interface to the offered IP address. * * @param netif network interface to bind to the offered address */static voiddhcp_bind(struct netif *netif){ u32_t timeout; struct dhcp *dhcp; ip_addr_t sn_mask, gw_addr; LWIP_ERROR("dhcp_bind: netif != NULL", (netif != NULL), return;); dhcp = netif->dhcp; LWIP_ERROR("dhcp_bind: dhcp != NULL", (dhcp != NULL), return;); 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)); /* temporary DHCP lease? */ if (dhcp->offered_t1_renew != 0xffffffffUL) { /* set renewal period timer */ LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE, ("dhcp_bind(): t1 renewal timer %"U32_F" secs\n", dhcp->offered_t1_renew)); timeout = (dhcp->offered_t1_renew + DHCP_COARSE_TIMER_SECS / 2) / DHCP_COARSE_TIMER_SECS; if(timeout > 0xffff) { timeout = 0xffff; } dhcp->t1_timeout = (u16_t)timeout; if (dhcp->t1_timeout == 0) { dhcp->t1_timeout = 1; } LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE, ("dhcp_bind(): set request timeout %"U32_F" msecs\n", dhcp->offered_t1_renew*1000)); } /* set renewal period timer */ if (dhcp->offered_t2_rebind != 0xffffffffUL) { LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE, ("dhcp_bind(): t2 rebind timer %"U32_F" secs\n", dhcp->offered_t2_rebind)); timeout = (dhcp->offered_t2_rebind + DHCP_COARSE_TIMER_SECS / 2) / DHCP_COARSE_TIMER_SECS; if(timeout > 0xffff) { timeout = 0xffff; } dhcp->t2_timeout = (u16_t)timeout; if (dhcp->t2_timeout == 0) { dhcp->t2_timeout = 1; } LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE, ("dhcp_bind(): set request timeout %"U32_F" msecs\n", dhcp->offered_t2_rebind*1000)); } if (dhcp->subnet_mask_given) { /* copy offered network mask */ ip_addr_copy(sn_mask, dhcp->offered_sn_mask); } else { /* subnet mask not given, choose a safe subnet mask given the network class */ u8_t first_octet = ip4_addr1(&dhcp->offered_ip_addr); if (first_octet <= 127) { ip4_addr_set_u32(&sn_mask, PP_HTONL(0xff000000UL)); } else if (first_octet >= 192) { ip4_addr_set_u32(&sn_mask, PP_HTONL(0xffffff00UL)); } else { ip4_addr_set_u32(&sn_mask, PP_HTONL(0xffff0000UL)); } } ip_addr_copy(gw_addr, dhcp->offered_gw_addr); /* gateway address not given? */ if (ip_addr_isany(&gw_addr)) { /* copy network address */ ip_addr_get_network(&gw_addr, &dhcp->offered_ip_addr, &sn_mask); /* use first host address on network as gateway */ ip4_addr_set_u32(&gw_addr, ip4_addr_get_u32(&gw_addr) | PP_HTONL(0x00000001UL)); }#if LWIP_DHCP_AUTOIP_COOP if(dhcp->autoip_coop_state == DHCP_AUTOIP_COOP_STATE_ON) { autoip_stop(netif); dhcp->autoip_coop_state = DHCP_AUTOIP_COOP_STATE_OFF; }#endif /* LWIP_DHCP_AUTOIP_COOP */ LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_STATE, ("dhcp_bind(): IP: 0x%08"X32_F"\n", ip4_addr_get_u32(&dhcp->offered_ip_addr))); netif_set_ipaddr(netif, &dhcp->offered_ip_addr); LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_STATE, ("dhcp_bind(): SN: 0x%08"X32_F"\n", ip4_addr_get_u32(&sn_mask))); netif_set_netmask(netif, &sn_mask); LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_STATE, ("dhcp_bind(): GW: 0x%08"X32_F"\n", ip4_addr_get_u32(&gw_addr))); netif_set_gw(netif, &gw_addr); /* bring the interface up */ netif_set_up(netif); /* netif is now bound to DHCP leased address */ dhcp_set_state(dhcp, DHCP_BOUND);}/** * Renew an existing DHCP lease at the involved DHCP server. * * @param netif network interface which must renew its lease */err_tdhcp_renew(struct netif *netif){ struct dhcp *dhcp = netif->dhcp; err_t result; u16_t msecs; LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE, ("dhcp_renew()\n")); dhcp_set_state(dhcp, DHCP_RENEWING); /* create and initialize the DHCP message header */ result = dhcp_create_msg(netif, dhcp, DHCP_REQUEST); if (result == ERR_OK) { dhcp_option(dhcp, DHCP_OPTION_MAX_MSG_SIZE, DHCP_OPTION_MAX_MSG_SIZE_LEN); dhcp_option_short(dhcp, DHCP_MAX_MSG_LEN(netif));#if LWIP_NETIF_HOSTNAME if (netif->hostname != NULL) { const char *p = (const char*)netif->hostname; u8_t namelen = (u8_t)strlen(p); if (namelen > 0) { LWIP_ASSERT("DHCP: hostname is too long!", namelen < 255); dhcp_option(dhcp, DHCP_OPTION_HOSTNAME, namelen); while (*p) { dhcp_option_byte(dhcp, *p++); } } }#endif /* LWIP_NETIF_HOSTNAME */#if 0 dhcp_option(dhcp, DHCP_OPTION_REQUESTED_IP, 4); dhcp_option_long(dhcp, ntohl(dhcp->offered_ip_addr.addr));#endif#if 0 dhcp_option(dhcp, DHCP_OPTION_SERVER_ID, 4); dhcp_option_long(dhcp, ntohl(dhcp->server_ip_addr.addr));#endif /* append DHCP message trailer */ dhcp_option_trailer(dhcp); pbuf_realloc(dhcp->p_out, sizeof(struct dhcp_msg) - DHCP_OPTIONS_LEN + dhcp->options_out_len); udp_sendto_if(dhcp->pcb, dhcp->p_out, &dhcp->server_ip_addr, DHCP_SERVER_PORT, netif); dhcp_delete_msg(dhcp); LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE, ("dhcp_renew: RENEWING\n")); } else { LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_LEVEL_SERIOUS, ("dhcp_renew: could not allocate DHCP request\n")); } dhcp->tries++; /* back-off on retries, but to a maximum of 20 seconds */ msecs = dhcp->tries < 10 ? dhcp->tries * 2000 : 20 * 1000; dhcp->request_timeout = (msecs + DHCP_FINE_TIMER_MSECS - 1) / DHCP_FINE_TIMER_MSECS; LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE, ("dhcp_renew(): set request timeout %"U16_F" msecs\n", msecs)); return result;}/** * Rebind with a DHCP server for an existing DHCP lease. * * @param netif network interface which must rebind with a DHCP server */static err_tdhcp_rebind(struct netif *netif){ struct dhcp *dhcp = netif->dhcp; err_t result; u16_t msecs; LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE, ("dhcp_rebind()\n")); dhcp_set_state(dhcp, DHCP_REBINDING); /* create and initialize the DHCP message header */ result = dhcp_create_msg(netif, dhcp, DHCP_REQUEST); if (result == ERR_OK) { dhcp_option(dhcp, DHCP_OPTION_MAX_MSG_SIZE, DHCP_OPTION_MAX_MSG_SIZE_LEN); dhcp_option_short(dhcp, DHCP_MAX_MSG_LEN(netif));#if LWIP_NETIF_HOSTNAME if (netif->hostname != NULL) { const char *p = (const char*)netif->hostname; u8_t namelen = (u8_t)strlen(p); if (namelen > 0) { LWIP_ASSERT("DHCP: hostname is too long!", namelen < 255); dhcp_option(dhcp, DHCP_OPTION_HOSTNAME, namelen); while (*p) { dhcp_option_byte(dhcp, *p++); } } }#endif /* LWIP_NETIF_HOSTNAME */#if 0 dhcp_option(dhcp, DHCP_OPTION_REQUESTED_IP, 4); dhcp_option_long(dhcp, ntohl(dhcp->offered_ip_addr.addr)); dhcp_option(dhcp, DHCP_OPTION_SERVER_ID, 4); dhcp_option_long(dhcp, ntohl(dhcp->server_ip_addr.addr));#endif dhcp_option_trailer(dhcp); pbuf_realloc(dhcp->p_out, sizeof(struct dhcp_msg) - DHCP_OPTIONS_LEN + dhcp->options_out_len); /* broadcast to server */ udp_sendto_if(dhcp->pcb, dhcp->p_out, IP_ADDR_BROADCAST, DHCP_SERVER_PORT, netif); dhcp_delete_msg(dhcp); LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE, ("dhcp_rebind: REBINDING\n")); } else { LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_LEVEL_SERIOUS, ("dhcp_rebind: could not allocate DHCP request\n")); } dhcp->tries++; msecs = dhcp->tries < 10 ? dhcp->tries * 1000 : 10 * 1000; dhcp->request_timeout = (msecs + DHCP_FINE_TIMER_MSECS - 1) / DHCP_FINE_TIMER_MSECS; LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE, ("dhcp_rebind(): set request timeout %"U16_F" msecs\n", msecs)); return result;}/** * Enter REBOOTING state to verify an existing lease * * @param netif network interface which must reboot */static err_tdhcp_reboot(struct netif *netif){ struct dhcp *dhcp = netif->dhcp; err_t result; u16_t msecs; LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE, ("dhcp_reboot()\n")); dhcp_set_state(dhcp, DHCP_REBOOTING); /* create and initialize the DHCP message header */ result = dhcp_create_msg(netif, dhcp, DHCP_REQUEST); if (result == ERR_OK) { dhcp_option(dhcp, DHCP_OPTION_MAX_MSG_SIZE, DHCP_OPTION_MAX_MSG_SIZE_LEN); dhcp_option_short(dhcp, 576); dhcp_option(dhcp, DHCP_OPTION_REQUESTED_IP, 4); dhcp_option_long(dhcp, ntohl(ip4_addr_get_u32(&dhcp->offered_ip_addr))); dhcp_option_trailer(dhcp); pbuf_realloc(dhcp->p_out, sizeof(struct dhcp_msg) - DHCP_OPTIONS_LEN + dhcp->options_out_len); /* broadcast to server */ udp_sendto_if(dhcp->pcb, dhcp->p_out, IP_ADDR_BROADCAST, DHCP_SERVER_PORT, netif); dhcp_delete_msg(dhcp); LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE, ("dhcp_reboot: REBOOTING\n")); } else { LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_LEVEL_SERIOUS, ("dhcp_reboot: could not allocate DHCP request\n")); } dhcp->tries++; msecs = dhcp->tries < 10 ? dhcp->tries * 1000 : 10 * 1000; dhcp->request_timeout = (msecs + DHCP_FINE_TIMER_MSECS - 1) / DHCP_FINE_TIMER_MSECS; LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE, ("dhcp_reboot(): set request timeout %"U16_F" msecs\n", msecs)); return result;}/** * Release a DHCP lease. * * @param netif network interface which must release its lease */err_tdhcp_release(struct netif *netif){ struct dhcp *dhcp = netif->dhcp; err_t result; u16_t msecs; LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE, ("dhcp_release()\n")); /* idle DHCP client */ dhcp_set_state(dhcp, DHCP_OFF); /* clean old DHCP offer */ ip_addr_set_zero(&dhcp->server_ip_addr); ip_addr_set_zero(&dhcp->offered_ip_addr); ip_addr_set_zero(&dhcp->offered_sn_mask); ip_addr_set_zero(&dhcp->offered_gw_addr);#if LWIP_DHCP_BOOTP_FILE ip_addr_set_zero(&dhcp->offered_si_addr);#endif /* LWIP_DHCP_BOOTP_FILE */ dhcp->offered_t0_lease = dhcp->offered_t1_renew = dhcp->offered_t2_rebind = 0; /* create and initialize the DHCP message header */ result = dhcp_create_msg(netif, dhcp, DHCP_RELEASE); if (result == ERR_OK) { dhcp_option_trailer(dhcp); pbuf_realloc(dhcp->p_out, sizeof(struct dhcp_msg) - DHCP_OPTIONS_LEN + dhcp->options_out_len); udp_sendto_if(dhcp->pcb, dhcp->p_out, &dhcp->server_ip_addr, DHCP_SERVER_PORT, netif); dhcp_delete_msg(dhcp); LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE, ("dhcp_release: RELEASED, DHCP_OFF\n")); } else { LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_LEVEL_SERIOUS, ("dhcp_release: could not allocate DHCP request\n")); } dhcp->tries++; msecs = dhcp->tries < 10 ? dhcp->tries * 1000 : 10 * 1000; dhcp->request_timeout = (msecs + DHCP_FINE_TIMER_MSECS - 1) / DHCP_FINE_TIMER_MSECS; LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE, ("dhcp_release(): set request timeout %"U16_F" msecs\n", msecs)); /* bring the interface down */ netif_set_down(netif); /* remove IP address from interface */ netif_set_ipaddr(netif, IP_ADDR_ANY); netif_set_gw(netif, IP_ADDR_ANY); netif_set_netmask(netif, IP_ADDR_ANY); return result;}/** * Remove the DHCP client from the interface. * * @param netif The network interface to stop DHCP on */voiddhcp_stop(struct netif *netif){ struct dhcp *dhcp; LWIP_ERROR("dhcp_stop: netif != NULL", (netif != NULL), return;); dhcp = netif->dhcp; /* Remove the flag that says this netif is handled by DHCP. */ netif->flags &= ~NETIF_FLAG_DHCP; LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE, ("dhcp_stop()\n")); /* netif is DHCP configured? */ if (dhcp != NULL) {#if LWIP_DHCP_AUTOIP_COOP if(dhcp->autoip_coop_state == DHCP_AUTOIP_COOP_STATE_ON) { autoip_stop(netif); dhcp->autoip_coop_state = DHCP_AUTOIP_COOP_STATE_OFF; }#endif /* LWIP_DHCP_AUTOIP_COOP */ if (dhcp->pcb != NULL) { udp_remove(dhcp->pcb); dhcp->pcb = NULL; } LWIP_ASSERT("reply wasn't freed", dhcp->msg_in == NULL); dhcp_set_state(dhcp, DHCP_OFF); }}/* * Set the DHCP state of a DHCP client. * * If the state changed, reset the number of tries. */static voiddhcp_set_state(struct dhcp *dhcp, u8_t new_state){ if (new_state != dhcp->state) { dhcp->state = new_state; dhcp->tries = 0; dhcp->request_timeout = 0; }}/* * Concatenate an option type and length field to the outgoing * DHCP message. * */static voiddhcp_option(struct dhcp *dhcp, u8_t option_type, u8_t option_len){ LWIP_ASSERT("dhcp_option: dhcp->options_out_len + 2 + option_len <= DHCP_OPTIONS_LEN", dhcp->options_out_len + 2U + option_len <= DHCP_OPTIONS_LEN); dhcp->msg_out->options[dhcp->options_out_len++] = option_type; dhcp->msg_out->options[dhcp->options_out_len++] = option_len;}/* * Concatenate a single byte to the outgoing DHCP message. * */static voiddhcp_option_byte(struct dhcp *dhcp, u8_t value){ LWIP_ASSERT("dhcp_option_byte: dhcp->options_out_len < DHCP_OPTIONS_LEN", dhcp->options_out_len < DHCP_OPTIONS_LEN); dhcp->msg_out->options[dhcp->options_out_len++] = value;}static voiddhcp_option_short(struct dhcp *dhcp, u16_t value){ LWIP_ASSERT("dhcp_option_short: dhcp->options_out_len + 2 <= DHCP_OPTIONS_LEN", dhcp->options_out_len + 2U <= DHCP_OPTIONS_LEN); dhcp->msg_out->options[dhcp->options_out_len++] = (u8_t)((value & 0xff00U) >> 8); dhcp->msg_out->options[dhcp->options_out_len++] = (u8_t) (value & 0x00ffU);}static voiddhcp_option_long(struct dhcp *dhcp, u32_t value){ LWIP_ASSERT("dhcp_option_long: dhcp->options_out_len + 4 <= DHCP_OPTIONS_LEN", dhcp->options_out_len + 4U <= DHCP_OPTIONS_LEN); dhcp->msg_out->options[dhcp->options_out_len++] = (u8_t)((value & 0xff000000UL) >> 24); dhcp->msg_out->options[dhcp->options_out_len++] = (u8_t)((value & 0x00ff0000UL) >> 16); dhcp->msg_out->options[dhcp->options_out_len++] = (u8_t)((value & 0x0000ff00UL) >> 8); dhcp->msg_out->options[dhcp->options_out_len++] = (u8_t)((value & 0x000000ffUL));}/** * Extract the DHCP message and the DHCP options. * * Extract the DHCP message and the DHCP options, each into a contiguous * piece of memory. As a DHCP message is variable sized by its options, * and also allows overriding some fields for options, the easy approach * is to first unfold the options into a conitguous piece of memory, and * use that further on. * */static err_tdhcp_parse_reply(struct dhcp *dhcp, struct pbuf *p){ u8_t *options; u16_t offset; u16_t offset_max; u16_t options_idx; u16_t options_idx_max; struct pbuf *q; int parse_file_as_options = 0; int parse_sname_as_options = 0; /* clear received options */ dhcp_clear_all_options(dhcp); /* check that beginning of dhcp_msg (up to and including chaddr) is in first pbuf */ if (p->len < DHCP_SNAME_OFS) { return ERR_BUF; } dhcp->msg_in = (struct dhcp_msg *)p->payload;#if LWIP_DHCP_BOOTP_FILE /* clear boot file name */ dhcp->boot_file_name[0] = 0;#endif /* LWIP_DHCP_BOOTP_FILE */ /* parse options */ /* start with options field */ options_idx = DHCP_OPTIONS_OFS; /* parse options to the end of the received packet */ options_idx_max = p->tot_len;again: q = p; while((q != NULL) && (options_idx >= q->len)) { options_idx -= q->len; options_idx_max -= q->len; q = q->next; } if (q == NULL) { return ERR_BUF; } offset = options_idx; offset_max = options_idx_max; options = (u8_t*)q->payload; /* at least 1 byte to read and no end marker, then at least 3 bytes to read? */ while((q != NULL) && (options[offset] != DHCP_OPTION_END) && (offset < offset_max)) { u8_t op = options[offset]; u8_t len; u8_t decode_len = 0; int decode_idx = -1; u16_t val_offset = offset + 2; /* len byte might be in the next pbuf */ if (offset + 1 < q->len) { len = options[offset + 1]; } else { len = (q->next != NULL ? ((u8_t*)q->next->payload)[0] : 0); } /* LWIP_DEBUGF(DHCP_DEBUG, ("msg_offset=%"U16_F", q->len=%"U16_F, msg_offset, q->len)); */ decode_len = len; switch(op) { /* case(DHCP_OPTION_END): handled above */ case(DHCP_OPTION_PAD): /* special option: no len encoded */ decode_len = len = 0; /* will be increased below */ offset--; break; case(DHCP_OPTION_SUBNET_MASK): LWIP_ASSERT("len == 4", len == 4); decode_idx = DHCP_OPTION_IDX_SUBNET_MASK; break; case(DHCP_OPTION_ROUTER): decode_len = 4; /* only copy the first given router */ LWIP_ASSERT("len >= decode_len", len >= decode_len); decode_idx = DHCP_OPTION_IDX_ROUTER; break; case(DHCP_OPTION_DNS_SERVER): /* special case: there might be more than one server */ LWIP_ASSERT("len % 4 == 0", len % 4 == 0); /* limit number of DNS servers */ decode_len = LWIP_MIN(len, 4 * DNS_MAX_SERVERS); LWIP_ASSERT("len >= decode_len", len >= decode_len); decode_idx = DHCP_OPTION_IDX_DNS_SERVER; break; case(DHCP_OPTION_LEASE_TIME): LWIP_ASSERT("len == 4", len == 4); decode_idx = DHCP_OPTION_IDX_LEASE_TIME; break; case(DHCP_OPTION_OVERLOAD): LWIP_ASSERT("len == 1", len == 1); decode_idx = DHCP_OPTION_IDX_OVERLOAD; break; case(DHCP_OPTION_MESSAGE_TYPE): LWIP_ASSERT("len == 1", len == 1); decode_idx = DHCP_OPTION_IDX_MSG_TYPE; break; case(DHCP_OPTION_SERVER_ID): LWIP_ASSERT("len == 4", len == 4); decode_idx = DHCP_OPTION_IDX_SERVER_ID; break; case(DHCP_OPTION_T1): LWIP_ASSERT("len == 4", len == 4); decode_idx = DHCP_OPTION_IDX_T1; break; case(DHCP_OPTION_T2): LWIP_ASSERT("len == 4", len == 4); decode_idx = DHCP_OPTION_IDX_T2; break; default: decode_len = 0; LWIP_DEBUGF(DHCP_DEBUG, ("skipping option %"U16_F" in options\n", op)); break; } offset += len + 2; if (decode_len > 0) { u32_t value = 0; u16_t copy_len;decode_next: LWIP_ASSERT("check decode_idx", decode_idx >= 0 && decode_idx < DHCP_OPTION_IDX_MAX); LWIP_ASSERT("option already decoded", !dhcp_option_given(dhcp, decode_idx)); copy_len = LWIP_MIN(decode_len, 4); pbuf_copy_partial(q, &value, copy_len, val_offset); if (decode_len > 4) { /* decode more than one u32_t */ LWIP_ASSERT("decode_len % 4 == 0", decode_len % 4 == 0); dhcp_got_option(dhcp, decode_idx); dhcp_set_option_value(dhcp, decode_idx, htonl(value)); decode_len -= 4; val_offset += 4; decode_idx++; goto decode_next; } else if (decode_len == 4) { value = ntohl(value); } else { LWIP_ASSERT("invalid decode_len", decode_len == 1); value = ((u8_t*)&value)[0]; } dhcp_got_option(dhcp, decode_idx); dhcp_set_option_value(dhcp, decode_idx, value); } if (offset >= q->len) { offset -= q->len; offset_max -= q->len; q = q->next; options = (u8_t*)q->payload; } } /* is this an overloaded message? */ if (dhcp_option_given(dhcp, DHCP_OPTION_IDX_OVERLOAD)) { u32_t overload = dhcp_get_option_value(dhcp, DHCP_OPTION_IDX_OVERLOAD); dhcp_clear_option(dhcp, DHCP_OPTION_IDX_OVERLOAD); if (overload == DHCP_OVERLOAD_FILE) { parse_file_as_options = 1; LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE, ("overloaded file field\n")); } else if (overload == DHCP_OVERLOAD_SNAME) { parse_sname_as_options = 1; LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE, ("overloaded sname field\n")); } else if (overload == DHCP_OVERLOAD_SNAME_FILE) { parse_sname_as_options = 1; parse_file_as_options = 1; LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE, ("overloaded sname and file field\n")); } else { LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE, ("invalid overload option: %d\n", (int)overload)); }#if LWIP_DHCP_BOOTP_FILE if (!parse_file_as_options) { /* only do this for ACK messages */ if (dhcp_option_given(dhcp, DHCP_OPTION_IDX_MSG_TYPE) && (dhcp_get_option_value(dhcp, DHCP_OPTION_IDX_MSG_TYPE) == DHCP_ACK)) /* copy bootp file name, don't care for sname (server hostname) */ pbuf_copy_partial(p, dhcp->boot_file_name, DHCP_FILE_LEN-1, DHCP_FILE_OFS); /* make sure the string is really NULL-terminated */ dhcp->boot_file_name[DHCP_FILE_LEN-1] = 0; }#endif /* LWIP_DHCP_BOOTP_FILE */ } if (parse_file_as_options) { /* if both are overloaded, parse file first and then sname (RFC 2131 ch. 4.1) */ parse_file_as_options = 0; options_idx = DHCP_FILE_OFS; options_idx_max = DHCP_FILE_OFS + DHCP_FILE_LEN; goto again; } else if (parse_sname_as_options) { parse_sname_as_options = 0; options_idx = DHCP_SNAME_OFS; options_idx_max = DHCP_SNAME_OFS + DHCP_SNAME_LEN; goto again; } return ERR_OK;}/** * If an incoming DHCP message is in response to us, then trigger the state machine */static voiddhcp_recv(void *arg, struct udp_pcb *pcb, struct pbuf *p, ip_addr_t *addr, u16_t port){ struct netif *netif = (struct netif *)arg; struct dhcp *dhcp = netif->dhcp; struct dhcp_msg *reply_msg = (struct dhcp_msg *)p->payload; u8_t msg_type; u8_t i; 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, ip4_addr1_16(addr), ip4_addr2_16(addr), ip4_addr3_16(addr), ip4_addr4_16(addr), port)); LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE, ("pbuf->len = %"U16_F"\n", p->len)); LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE, ("pbuf->tot_len = %"U16_F"\n", p->tot_len)); /* prevent warnings about unused arguments */ LWIP_UNUSED_ARG(pcb); LWIP_UNUSED_ARG(addr); LWIP_UNUSED_ARG(port); LWIP_ASSERT("reply wasn't freed", dhcp->msg_in == NULL); if (p->len < DHCP_MIN_REPLY_LEN) { LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_LEVEL_WARNING, ("DHCP reply message or pbuf too short\n")); goto free_pbuf_and_return; } if (reply_msg->op != DHCP_BOOTREPLY) { 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)); goto free_pbuf_and_return; } /* iterate through hardware address and match against DHCP message */ for (i = 0; i < netif->hwaddr_len; i++) { if (netif->hwaddr[i] != reply_msg->chaddr[i]) { LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_LEVEL_WARNING, ("netif->hwaddr[%"U16_F"]==%02"X16_F" != reply_msg->chaddr[%"U16_F"]==%02"X16_F"\n", (u16_t)i, (u16_t)netif->hwaddr[i], (u16_t)i, (u16_t)reply_msg->chaddr[i])); goto free_pbuf_and_return; } } /* match transaction ID against what we expected */ if (ntohl(reply_msg->xid) != dhcp->xid) { LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_LEVEL_WARNING, ("transaction id mismatch reply_msg->xid(%"X32_F")!=dhcp->xid(%"X32_F")\n",ntohl(reply_msg->xid),dhcp->xid)); goto free_pbuf_and_return; } /* option fields could be unfold? */ if (dhcp_parse_reply(dhcp, p) != ERR_OK) { LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_LEVEL_SERIOUS, ("problem unfolding DHCP message - too short on memory?\n")); goto free_pbuf_and_return; } LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE, ("searching DHCP_OPTION_MESSAGE_TYPE\n")); /* obtain pointer to DHCP message type */ if (!dhcp_option_given(dhcp, DHCP_OPTION_IDX_MSG_TYPE)) { LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_LEVEL_WARNING, ("DHCP_OPTION_MESSAGE_TYPE option not found\n")); goto free_pbuf_and_return; } /* read DHCP message type */ msg_type = (u8_t)dhcp_get_option_value(dhcp, DHCP_OPTION_IDX_MSG_TYPE); /* message type is DHCP ACK? */ if (msg_type == DHCP_ACK) { LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE, ("DHCP_ACK received\n")); /* in requesting state? */ if (dhcp->state == DHCP_REQUESTING) { dhcp_handle_ack(netif);#if DHCP_DOES_ARP_CHECK /* check if the acknowledged lease address is already in use */ dhcp_check(netif);#else /* bind interface to the acknowledged lease address */ dhcp_bind(netif);#endif } /* already bound to the given lease address? */ else if ((dhcp->state == DHCP_REBOOTING) || (dhcp->state == DHCP_REBINDING) || (dhcp->state == DHCP_RENEWING)) { dhcp_bind(netif); } } /* received a DHCP_NAK in appropriate state? */ else if ((msg_type == DHCP_NAK) && ((dhcp->state == DHCP_REBOOTING) || (dhcp->state == DHCP_REQUESTING) || (dhcp->state == DHCP_REBINDING) || (dhcp->state == DHCP_RENEWING ))) { LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE, ("DHCP_NAK received\n")); dhcp_handle_nak(netif); } /* received a DHCP_OFFER in DHCP_SELECTING state? */ else if ((msg_type == DHCP_OFFER) && (dhcp->state == DHCP_SELECTING)) { LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE, ("DHCP_OFFER received in DHCP_SELECTING state\n")); dhcp->request_timeout = 0; /* remember offered lease */ dhcp_handle_offer(netif); }free_pbuf_and_return: dhcp->msg_in = NULL; pbuf_free(p);}/** * Create a DHCP request, fill in common headers * * @param netif the netif under DHCP control * @param dhcp dhcp control struct * @param message_type message type of the request */static err_tdhcp_create_msg(struct netif *netif, struct dhcp *dhcp, u8_t message_type){ u16_t i;#ifndef DHCP_GLOBAL_XID /** default global transaction identifier starting value (easy to match * with a packet analyser). We simply increment for each new request. * Predefine DHCP_GLOBAL_XID to a better value or a function call to generate one * at runtime, any supporting function prototypes can be defined in DHCP_GLOBAL_XID_HEADER */ static u32_t xid = 0xABCD0000;#else static u32_t xid; static u8_t xid_initialised = 0; if (!xid_initialised) { xid = DHCP_GLOBAL_XID; xid_initialised = !xid_initialised; }#endif LWIP_ERROR("dhcp_create_msg: netif != NULL", (netif != NULL), return ERR_ARG;); LWIP_ERROR("dhcp_create_msg: dhcp != NULL", (dhcp != NULL), return ERR_VAL;); LWIP_ASSERT("dhcp_create_msg: dhcp->p_out == NULL", dhcp->p_out == NULL); LWIP_ASSERT("dhcp_create_msg: dhcp->msg_out == NULL", dhcp->msg_out == NULL); dhcp->p_out = pbuf_alloc(PBUF_TRANSPORT, sizeof(struct dhcp_msg), PBUF_RAM); if (dhcp->p_out == NULL) { LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_LEVEL_SERIOUS, ("dhcp_create_msg(): could not allocate pbuf\n")); return ERR_MEM; } LWIP_ASSERT("dhcp_create_msg: check that first pbuf can hold struct dhcp_msg", (dhcp->p_out->len >= sizeof(struct dhcp_msg))); /* reuse transaction identifier in retransmissions */ if (dhcp->tries == 0) { xid++; } dhcp->xid = xid; LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE, ("transaction id xid(%"X32_F")\n", xid)); dhcp->msg_out = (struct dhcp_msg *)dhcp->p_out->payload; dhcp->msg_out->op = DHCP_BOOTREQUEST; /* TODO: make link layer independent */ dhcp->msg_out->htype = DHCP_HTYPE_ETH; dhcp->msg_out->hlen = netif->hwaddr_len; dhcp->msg_out->hops = 0; dhcp->msg_out->xid = htonl(dhcp->xid); dhcp->msg_out->secs = 0; /* we don't need the broadcast flag since we can receive unicast traffic before being fully configured! */ dhcp->msg_out->flags = 0; ip_addr_set_zero(&dhcp->msg_out->ciaddr); /* set ciaddr to netif->ip_addr based on message_type and state */ if ((message_type == DHCP_INFORM) || (message_type == DHCP_DECLINE) || ((message_type == DHCP_REQUEST) && /* DHCP_BOUND not used for sending! */ ((dhcp->state==DHCP_RENEWING) || dhcp->state==DHCP_REBINDING))) { ip_addr_copy(dhcp->msg_out->ciaddr, netif->ip_addr); } ip_addr_set_zero(&dhcp->msg_out->yiaddr); ip_addr_set_zero(&dhcp->msg_out->siaddr); ip_addr_set_zero(&dhcp->msg_out->giaddr); for (i = 0; i < DHCP_CHADDR_LEN; i++) { /* copy netif hardware address, pad with zeroes */ dhcp->msg_out->chaddr[i] = (i < netif->hwaddr_len) ? netif->hwaddr[i] : 0/* pad byte*/; } for (i = 0; i < DHCP_SNAME_LEN; i++) { dhcp->msg_out->sname[i] = 0; } for (i = 0; i < DHCP_FILE_LEN; i++) { dhcp->msg_out->file[i] = 0; } dhcp->msg_out->cookie = PP_HTONL(DHCP_MAGIC_COOKIE); dhcp->options_out_len = 0; /* fill options field with an incrementing array (for debugging purposes) */ for (i = 0; i < DHCP_OPTIONS_LEN; i++) { dhcp->msg_out->options[i] = (u8_t)i; /* for debugging only, no matter if truncated */ } /* Add option MESSAGE_TYPE */ dhcp_option(dhcp, DHCP_OPTION_MESSAGE_TYPE, DHCP_OPTION_MESSAGE_TYPE_LEN); dhcp_option_byte(dhcp, message_type); return ERR_OK;}/** * Free previously allocated memory used to send a DHCP request. * * @param dhcp the dhcp struct to free the request from */static voiddhcp_delete_msg(struct dhcp *dhcp){ LWIP_ERROR("dhcp_delete_msg: dhcp != NULL", (dhcp != NULL), return;); LWIP_ASSERT("dhcp_delete_msg: dhcp->p_out != NULL", dhcp->p_out != NULL); LWIP_ASSERT("dhcp_delete_msg: dhcp->msg_out != NULL", dhcp->msg_out != NULL); if (dhcp->p_out != NULL) { pbuf_free(dhcp->p_out); } dhcp->p_out = NULL; dhcp->msg_out = NULL;}/** * Add a DHCP message trailer * * Adds the END option to the DHCP message, and if * necessary, up to three padding bytes. * * @param dhcp DHCP state structure */static voiddhcp_option_trailer(struct dhcp *dhcp){ LWIP_ERROR("dhcp_option_trailer: dhcp != NULL", (dhcp != NULL), return;); LWIP_ASSERT("dhcp_option_trailer: dhcp->msg_out != NULL\n", dhcp->msg_out != NULL); LWIP_ASSERT("dhcp_option_trailer: dhcp->options_out_len < DHCP_OPTIONS_LEN\n", dhcp->options_out_len < DHCP_OPTIONS_LEN); dhcp->msg_out->options[dhcp->options_out_len++] = DHCP_OPTION_END; /* packet is too small, or not 4 byte aligned? */ while ((dhcp->options_out_len < DHCP_MIN_OPTIONS_LEN) || (dhcp->options_out_len & 3)) { /* 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)); */ LWIP_ASSERT("dhcp_option_trailer: dhcp->options_out_len < DHCP_OPTIONS_LEN\n", dhcp->options_out_len < DHCP_OPTIONS_LEN); /* add a fill/padding byte */ dhcp->msg_out->options[dhcp->options_out_len++] = 0; }}#endif /* LWIP_DHCP */
