Re: [lwip-users] DHCP usage

[Adam Fullerton]

Hi Sandra,

I e-mailed you directly as I don't like appearing on the lwIP mail list.

I'm the wrong person to ask as I use the socket API. The only place where I use the lwIP functions is in the interface layer which binds the Ethernet drivers to lwIP, hence the abstraction layer functions such as ipReconfigure etc...

Probably worth posting the question though.

Cheers,

Adam.

On 05/06/2015 14:05, Sandra Gilge wrote:

Hallo,

 

thanks, I’m doing the dhcp_release and can see it in wireshark now.

Since I work with lwipv1.4.1 I use the netifapi functions. For dhcp release I call netifapi_netif_common(netif, NULL, dhcp_release);

 

That leads to another questions:

Wouldn’t it make sense to have a define in netifapi.h for dhcp_release as follows:

#define netifapi_dhcp_release(n)        netifapi_netif_common(n, NULL, dhcp_release)

 

Best regards,

Sandra

 

 

 

Gesendet: Freitag, 5. Juni 2015 11:07
An: Sandra Gilge
Betreff: Fwd: [lwip-users] DHCP usage

 

Hi,

I had issues with this too. This is what I did and it has worked with out change from lwIP V1.3.2 to current:

typedef struct _NVDHCP
{
    uint8_t         pbyIpAddress[4];
    uint8_t         pbyAddressMask[4];
    uint8_t         pbyGatewayAddress[4];
    uint8_t         byEnableDHCP;
} NVDHCP,
*PNVDHCP;

/******************************************************************************
* Function Name: ipReconfigure
* Description  : Function to re-configure the interface
* Arguments    : IN  pszInterface - The symbolic link name of the interface
*                IN  pIpConfig - Pointer to the new configuration
* Return Value : 0 for success or -1 on error
******************************************************************************/
int32_t ipReconfigure(int8_t *pszInterface, PNVDHCP pIpConfig)
{
    PRTEIP pEtherC = ipFindNetIf(&gpEtherC, pszInterface);
    if (pEtherC)
    {
        if (pIpConfig->byEnableDHCP == 0U)
        {
            _Bool    bfLinkUp = false;
            pEtherC->ipConfig = *pIpConfig;
            /* If DHCP was previously on */
            if (pEtherC->ipConfig.byEnableDHCP)
            {
                /* Stop it */
                tcpip_callback((void(*)(void*))dhcp_release,
                               &pEtherC->ipNetIf);
                tcpip_callback((void(*)(void*))dhcp_stop,
                &pEtherC->ipNetIf);
            }
            /* Set the fixed address */
            memcpy(&pEtherC->ipNetIf.ip_addr.addr,
                   pEtherC->ipConfig.pbyIpAddress,
                   sizeof(struct ip_addr));
            memcpy(&pEtherC->ipNetIf.netmask.addr,
                   pEtherC->ipConfig.pbyAddressMask,
                   sizeof(struct ip_addr));
            memcpy(&pEtherC->ipNetIf.gw.addr,
                   pEtherC->ipConfig.pbyGatewayAddress,
                   sizeof(struct ip_addr));
            /* Check the state of the link */
            if ((control(pEtherC->iEtherC, CTL_GET_LINK_STATE, &bfLinkUp) == 0U)
            &&  (bfLinkUp))
            {
                /* Tell lwIP that the data link is up */
                tcpip_callback((void(*)(void*))netif_set_up,
                               &pEtherC->ipNetIf);
            }
        }
        else
        {
            if (pEtherC->ipConfig.byEnableDHCP == 0U)
            {
                pEtherC->ipConfig = *pIpConfig;
                /* Protect against concurrent access,
                   specifically in the ARP modules */
                tcpip_callback((void(*)(void*))netif_set_link_down,
                               &pEtherC->ipNetIf);
                /* Also have to do this one as well. Is it not obvious
                   that if the physical link has been set down that
                   the data link is down too? */
                tcpip_callback((void(*)(void*))netif_set_down,
                               &pEtherC->ipNetIf);
                /* Tell lwIP to start DHCP */
                tcpip_callback((void(*)(void*))dhcp_start,
                               &pEtherC->ipNetIf);
            }
            else
            {
                pEtherC->ipConfig = *pIpConfig;
            }
        }
        return 0;
    }
    return -1;
}
/******************************************************************************
End of function  ipReconfigure
******************************************************************************/

The code comes from a system using an RTOS so the calls are made by call-backs to the TCPIP task.

Good luck!

Adam.

-------- Forwarded Message --------

Subject:	[lwip-users] DHCP usage
Date:	Fri, 5 Jun 2015 10:37:00 +0200
From:	Sandra Gilge <address@hidden>
Reply-To:	Mailing list for lwIP users <address@hidden>
To:	address@hidden

Hallo,

 

The IP configuration in our embedded system is reconfigurable by the user during runtime.

The user can also switch on DHCP or switch it off and use a static IP address.

 

What is the correct way to switch DHCP off. Do I have to call netifapi_dhcp_stop(), when switching off DHCP?

I tried this, but I could not see a DHCP message on wireshark.

 

This is how it works right now:

Any configuration change:

netifapi_netif_set_down()

 

DHCP switched off:

netifapi_netif_set_addr()

netifapi_netif_set_up()

 

DHCP switched on:

netifapi_dhcp_start()

wait up to 7 secs for DHCP_BOUND

 

Best regards,

Sandra

 

 

 

 

 

 

 

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