[lwip-users] patch etharp

[Andreas Becker]

Hi all, 

im working on a DHCP extension to make it more RFC2131 compatible and able to 
use DHCP-Reboot. ( Patch comming soon.)

I noticed an wrong behavior, if we do an DHCP_DOES_ARP_CHECK with an 
unconfigured interface. First to assign an IP-number to our interface we have 
to (ARP-)check it. The answer is then "for_us" with an unconfigured 
Interface. But if we have an unconfigured Interface, the ARP-answer will not 
be processed.

So I think it's better to check, if the Ethernet-MAC of the received packet 
matches our MAC-address.

void
etharp_arp_input(struct netif *netif, struct eth_addr *ethaddr, struct pbuf 
*p)
{
....
  /* this interface is not configured? */
#if 0
  if (netif->ip_addr.addr == 0) {
    for_us = 0;
  } else {
     /* ARP packet directed to us? */
    for_us = ip_addr_cmp(&dipaddr, &(netif->ip_addr));
  }
#else
  if (memcmp(netif->hwaddr, ethaddr, netif->hwaddr_len) == 0 /*equal*/)
  {
    for_us = 1;
  }
  else
  {
    for_us = 0;
  }
#endif


Regards, 

-- 
MEng Dipl.-Ing.(FH) Andreas Becker
Entwicklung

dSys e.K.
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D-89077 Ulm
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