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lwip/src/core/dhcp.c

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/**
* @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_SERVER 8
#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_CHECK
static 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 request, fill in common headers */
static err_t dhcp_create_request(struct netif *netif, struct dhcp *dhcp);
/* free a DHCP request */
static void dhcp_delete_request(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 void
dhcp_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 void
dhcp_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 void
dhcp_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_set(&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_t
dhcp_select(struct netif *netif)
{
struct dhcp *dhcp = netif->dhcp;
err_t result;
u16_t msecs;
#if LWIP_NETIF_HOSTNAME
const char *p;
#endif /* LWIP_NETIF_HOSTNAME */
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_request(netif, dhcp);
if (result == ERR_OK) {
dhcp_option(dhcp, DHCP_OPTION_MESSAGE_TYPE, DHCP_OPTION_MESSAGE_TYPE_LEN);
dhcp_option_byte(dhcp, DHCP_REQUEST);
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
p = (const char*)netif->hostname;
if (p != NULL) {
u8_t namelen = (u8_t)strlen(p);
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_request(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.
*/
void
dhcp_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.
*/
void
dhcp_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 void
dhcp_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 void
dhcp_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"));
dhcp_renew(netif);
}
}
/**
* The rebind period has timed out.
*
* @param netif the netif under DHCP control
*/
static void
dhcp_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"));
dhcp_rebind(netif);
}
}
/**
* Handle a DHCP ACK packet
*
* @param netif the netif under DHCP control
*/
static void
dhcp_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_set(&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_set(&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 */
}
/**
* 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_t
dhcp_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;
}
#if IP_SOF_BROADCAST
dhcp->pcb->so_options |= SOF_BROADCAST;
#endif /* IP_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
*/
void
dhcp_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;
#if IP_SOF_BROADCAST
dhcp.pcb->so_options |= SOF_BROADCAST;
#endif /* IP_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_request(netif, &dhcp);
if (result == ERR_OK) {
dhcp_option(&dhcp, DHCP_OPTION_MESSAGE_TYPE, DHCP_OPTION_MESSAGE_TYPE_LEN);
dhcp_option_byte(&dhcp, DHCP_INFORM);
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_request(&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.
*/
void
dhcp_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;
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_t
dhcp_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_request(netif, dhcp);
if (result == ERR_OK) {
dhcp_option(dhcp, DHCP_OPTION_MESSAGE_TYPE, DHCP_OPTION_MESSAGE_TYPE_LEN);
dhcp_option_byte(dhcp, DHCP_DECLINE);
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_request(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
/**
* Start the DHCP process, discover a DHCP server.
*
* @param netif the netif under DHCP control
*/
static err_t
dhcp_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_request(netif, dhcp);
if (result == ERR_OK) {
LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE, ("dhcp_discover: making request\n"));
dhcp_option(dhcp, DHCP_OPTION_MESSAGE_TYPE, DHCP_OPTION_MESSAGE_TYPE_LEN);
dhcp_option_byte(dhcp, DHCP_DISCOVER);
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_request(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 void
dhcp_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_set(&sn_mask, &dhcp->offered_sn_mask);
} else {
/* subnet mask not given, choose a safe subnet mask given the network class */
u8_t first_octet = (u8_t)ip4_addr1_16(&dhcp->offered_ip_addr);
if (first_octet <= 127) {
ip4_addr_set_u32(&sn_mask, htonl(0xff000000));
} else if (first_octet >= 192) {
ip4_addr_set_u32(&sn_mask, htonl(0xffffff00));
} else {
ip4_addr_set_u32(&sn_mask, htonl(0xffff0000));
}
}
ip_addr_set(&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) | htonl(0x00000001));
}
#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_t
dhcp_renew(struct netif *netif)
{
struct dhcp *dhcp = netif->dhcp;
err_t result;
u16_t msecs;
#if LWIP_NETIF_HOSTNAME
const char *p;
#endif /* LWIP_NETIF_HOSTNAME */
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_request(netif, dhcp);
if (result == ERR_OK) {
dhcp_option(dhcp, DHCP_OPTION_MESSAGE_TYPE, DHCP_OPTION_MESSAGE_TYPE_LEN);
dhcp_option_byte(dhcp, DHCP_REQUEST);
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
p = (const char*)netif->hostname;
if (p != NULL) {
u8_t namelen = (u8_t)strlen(p);
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_request(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_t
dhcp_rebind(struct netif *netif)
{
struct dhcp *dhcp = netif->dhcp;
err_t result;
u16_t msecs;
#if LWIP_NETIF_HOSTNAME
const char *p;
#endif /* LWIP_NETIF_HOSTNAME */
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_request(netif, dhcp);
if (result == ERR_OK) {
dhcp_option(dhcp, DHCP_OPTION_MESSAGE_TYPE, DHCP_OPTION_MESSAGE_TYPE_LEN);
dhcp_option_byte(dhcp, DHCP_REQUEST);
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
p = (const char*)netif->hostname;
if (p != NULL) {
u8_t namelen = (u8_t)strlen(p);
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_request(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_t
dhcp_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_request(netif, dhcp);
if (result == ERR_OK) {
dhcp_option(dhcp, DHCP_OPTION_MESSAGE_TYPE, DHCP_OPTION_MESSAGE_TYPE_LEN);
dhcp_option_byte(dhcp, DHCP_REQUEST);
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_request(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_t
dhcp_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_request(netif, dhcp);
if (result == ERR_OK) {
dhcp_option(dhcp, DHCP_OPTION_MESSAGE_TYPE, DHCP_OPTION_MESSAGE_TYPE_LEN);
dhcp_option_byte(dhcp, DHCP_RELEASE);
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_request(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
*/
void
dhcp_stop(struct netif *netif)
{
struct dhcp *dhcp = netif->dhcp;
LWIP_ERROR("dhcp_stop: netif != NULL", (netif != NULL), return;);
/* 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 void
dhcp_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 void
dhcp_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 void
dhcp_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 void
dhcp_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 void
dhcp_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_t
dhcp_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;
decode_idx++;
goto decode_next;
} else if (decode_len == 4) {
value = ntohl(value);
} else {
LWIP_ASSERT("invalid decode_len", decode_len == 1);
}
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 void
dhcp_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
*/
static err_t
dhcp_create_request(struct netif *netif, struct dhcp *dhcp)
{
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_request: netif != NULL", (netif != NULL), return ERR_ARG;);
LWIP_ERROR("dhcp_create_request: dhcp != NULL", (dhcp != NULL), return ERR_VAL;);
LWIP_ASSERT("dhcp_create_request: dhcp->p_out == NULL", dhcp->p_out == NULL);
LWIP_ASSERT("dhcp_create_request: 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_request(): could not allocate pbuf\n"));
return ERR_MEM;
}
LWIP_ASSERT("dhcp_create_request: 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);
if (dhcp->state==DHCP_BOUND || dhcp->state==DHCP_RENEWING || dhcp->state==DHCP_REBINDING) {
ip_addr_set(&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 = 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 */
}
return ERR_OK;
}
/**
* Free previously allocated memory used to send a DHCP request.
*
* @param dhcp the dhcp struct to free the request from
*/
static void
dhcp_delete_request(struct dhcp *dhcp)
{
LWIP_ERROR("dhcp_delete_request: dhcp != NULL", (dhcp != NULL), return;);
LWIP_ASSERT("dhcp_delete_request: dhcp->p_out != NULL", dhcp->p_out != NULL);
LWIP_ASSERT("dhcp_delete_request: 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 void
dhcp_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 */
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