lwip中etharp_query函数

caep1986

如果ip地址在arp表中有相应的表项存在，且表项处于stable状态，此时如果给定的数据包为空为什么还要向该ip地址发送一个arp请求？

aozima

1.   /* create an ARP query for the offered IP address, expecting that no host
   
2.      responds, as the IP address should not be in use. */
   
3.   result = etharp_query(netif, &dhcp->offered_ip_addr, NULL);
   

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1. err_t
   
2. etharp_query(struct netif *netif, ip_addr_t *ipaddr, struct pbuf *q)
   
3. {
   
4.   /* do we have a pending entry? or an implicit query request? */
   
5.   if ((arp_table[i].state == ETHARP_STATE_PENDING) || (q == NULL)) {
   

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caep1986

aozima 发表于 2014-3-29 21:26

懂了谢谢啦