Re: [lwip-users] DHCP server offer timing

[kuwa]

Hi, Leon and everyone,

From: address@hidden
Subject: Re: [lwip-users] DHCP server offer timing
Date: Sat, 13 Mar 2004 11:57:00 +0900 (LMT)

> For now, I am wondering how / where should I call dhcp_start()...
> Should it be called within TCP/IP task? (same context as TCP/IP context?)
> Should also DHPC timers are called within TCP/IP task?

Based on my assumption:
      dhcp_start() and DHCP timers should be called
      inside the tcpip_thread() for mutli-threaded environment

I try to make DHCP start API which is for calling dhcp_start() inside
tcpip_thread() context.

This seems to solve my problem of multi-threaded safety, however I
don't think this is smart way and code.  So I send this as FYI.

I cannot simply create diffs because in my system lwIP is fairly
modified and currently not arranged.  Sorry for incovenience.


Add new file src/api/api_dhcp.c:

This is an API function.

Application thread just calls this function same as dhcp_start().
-----------------------------------------------------
#include "lwip/opt.h"

#if defined(LWIP_DHCP) && defined(DHCP_USE_API)
#include "lwip/api.h"
#include "lwip/api_msg.h"
#include "lwip/api_dhcp.h"
#include "lwip/memp.h"

err_t
api_dhcp_start(struct netif *netif)
{
  struct netconn *conn;
  struct api_msg *msg;
  err_t err = ERR_OK;

  if (netif == NULL) {
    return ERR_ARG;
  }

  conn = memp_malloc(MEMP_NETCONN);
  if (conn == NULL) {
    return ERR_MEM;
  }

  conn->err = ERR_OK;
  if ((conn->mbox = sys_mbox_new()) == SYS_MBOX_NULL) {
    memp_free(MEMP_NETCONN, conn);
    return ERR_MEM;
  }

  if ((msg = memp_malloc(MEMP_API_MSG)) == NULL) {
    memp_free(MEMP_NETCONN, conn);
    return ERR_MEM;
  }
  msg->type = API_MSG_START_DHCP; /* Start DHCP */
  msg->msg.conn = conn;
  msg->msg.msg.w.dataptr = netif;

  api_msg_post(msg);  
  sys_mbox_fetch(conn->mbox, NULL);
  memp_free(MEMP_API_MSG, msg);

  err = conn->err;
  memp_free(MEMP_NETCONN, conn);
  return err;
}
#endif
-----------------------------------------------------

Add new file src/include/lwip/api_dhcp.h:
-----------------------------------------------------
#ifndef __LWIP_API_DHCP_H__
#define __LWIP_API_DHCP_H__

#include "lwip/opt.h"
#include "lwip/sys.h"
#include "lwip/netif.h"
#include "lwip/err.h"

#if defined(LWIP_DHCP) && defined(DHCP_USE_API)
err_t api_dhcp_start(struct netif *netif);
#endif

#endif /* __LWIP_API_DHCP_H__ */
-----------------------------------------------------

Add do_dhcp_start() in src/api/api_msg.c:
This function registers two DHCP timers and calls dhcp_start() inside
tcpip_thread().

-----------------------------------------------------
#if defined(LWIP_DHCP) && defined(DHCP_USE_API)
static void
dhcp_fine_timer(void *arg)
{
  dhcp_fine_tmr();
  sys_timeout(DHCP_FINE_TIMER_MSECS,
              (sys_timeout_handler)dhcp_fine_timer, NULL);
}

static void
dhcp_coarse_timer(void *arg)
{
  dhcp_coarse_tmr();
  sys_timeout((u32_t)DHCP_COARSE_TIMER_SECS * 1000,
              (sys_timeout_handler)dhcp_coarse_timer, NULL);
}

static void
do_dhcp_start(struct api_msg_msg *msg)
{
  extern err_t dhcp_start(struct netif *);

  sys_timeout(DHCP_FINE_TIMER_MSECS,
              (sys_timeout_handler)dhcp_fine_timer, NULL);
  sys_timeout((u32_t)DHCP_COARSE_TIMER_SECS * 1000,
              (sys_timeout_handler)dhcp_coarse_timer, NULL);
  msg->conn->err = dhcp_start((struct netif *)msg->msg.w.dataptr);
  sys_mbox_post(msg->conn->mbox, NULL);
}
#endif /* defined(LWIP_DHCP) && defined(DHCP_USE_API) */
-----------------------------------------------------

Registers the above do_dhcp_start() to api_msg_decode table in
src/api/api_msg.c.
-----------------------------------------------------
typedef void (* api_msg_decode)(struct api_msg_msg *msg);
static api_msg_decode decode[API_MSG_MAX] = {
  do_newconn,
  do_delconn,
  do_bind,
  do_connect,
  do_disconnect,
  do_listen,
  do_accept,
  do_send,
  do_recv,
  do_write,
  do_close
#if defined(LWIP_DHCP) && defined(DHCP_USE_API)
  ,
  do_dhcp_start
#endif
  };
-----------------------------------------------------

Registers new api message type "API_MSG_START_DHCP" in
src/include/lwip/api_msg.h:

-----------------------------------------------------
enum api_msg_type {
  API_MSG_NEWCONN,
  API_MSG_DELCONN,
  
  API_MSG_BIND,
  API_MSG_CONNECT,
  API_MSG_DISCONNECT,

  API_MSG_LISTEN,
  API_MSG_ACCEPT,

  API_MSG_SEND,
  API_MSG_RECV,
  API_MSG_WRITE,

  API_MSG_CLOSE,
  
#if defined(LWIP_DHCP) && defined(DHCP_USE_API)
  API_MSG_START_DHCP,
#endif
  API_MSG_MAX
};
-----------------------------------------------------

--
Shuji KUWAHARA