关于rtt1.1.0+enc28j60+lwip使用DHCP时IP续约的问题

发布于 2014-07-22 19:44:58 浏览：5922 订阅该版

前面一个帖子（https://club.rt-thread.org/ask/question/3688.html）提到【STM32+RT-Thread+ENC28J60+LWIP用DHCP时网卡不能从掉电模式恢复】的问题，折腾了非常长一段时间，经最新调试发现：dhcp.c中，只有dhcp_timeout和dhcp_t2_timeout会被执行，dhcp_t1_timeout却没有被执行，而dhcp_t1_timeout正是负责dhcp_renew的超时函数，请问这是什么原因？是rtt1.1.0中lwip移植不完善导致的吗？

此外，由于在网卡进入掉电模式后，lwip的dhcp仍然会执行一些需要网络连接的事务，这也是导致我之前遇到网卡掉电后不能正常恢复通信的另一个原因，目前我在以上提到的几个timeout中首先调用enc28j60_powersave_exit()让网卡退出掉电模式后再让dhcp执行后续的网络操作，似乎基本能够正常恢复通信了，但也是此时我才发现dhcp_t1_timeout没有被调用，而dhcp_t2_timeout却被调用了。

求解答。

```
extern  void enc28j60_powersave_exit(void);
static void
dhcp_timeout(struct netif *netif)
{
  struct dhcp *dhcp = netif->dhcp;
  LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE, ("dhcp_timeout()
"));
  
  enc28j60_powersave_exit();/*modified by xhly to solve the enc28j60 powersave problem*/
  
  /* 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
"));
    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
"));
    if (dhcp->tries <= 5) {
      dhcp_select(netif);
    } else {
      LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE, ("dhcp_timeout(): REQUESTING, releasing, restarting
"));
      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
"));
    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
"));
    /* 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
"));
    if (dhcp->tries <= 8) {
      dhcp_rebind(netif);
    } else {
      LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE, ("dhcp_timeout(): RELEASING, DISCOVERING
"));
      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()
"));
  
  enc28j60_powersave_exit();
  
  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
"));
    /* 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 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()
"));
  
  enc28j60_powersave_exit();
  
  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
"));
    /* This slightly different to RFC2131: DHCPREQUEST will be sent from state
       DHCP_REBINDING, not DHCP_BOUND */
    dhcp_rebind(netif);
  }
}

```

7 个回答

xhly 2014-07-22

这家伙很懒，什么也没写！

xhly 2014-07-22

这家伙很懒，什么也没写！

哈哈，找到原因了：

```
  
/** period (in seconds) of the application calling dhcp_coarse_tmr() */
#define DHCP_COARSE_TIMER_SECS 60 //60s为单位，导致t1只有等60+s才会被执行。。。。，改为30就行了

/* 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
", 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
", 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
", 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
", dhcp->offered_t2_rebind*1000));
  }

```