dhcp.c

来自「lwip-1.4.0」· C语言 代码 · 共 1,746 行 · 第 1/5 页

    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_t
dhcp_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_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_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_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_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
 */
void
dhcp_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 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);