*
* Functionally, ARP is divided into two parts. The first maps an IP address
* to a physical address when sending a packet, and the second part answers
- * requests from other machines.
+ * requests from other machines for our physical address.
*
+ * This implementation complies with RFC 826 (Ethernet ARP) and supports
+ * Gratuitious ARP from RFC3220 (IP Mobility Support for IPv4) section 4.6.
*/
/*
if ((arp_table[i].state == ETHARP_STATE_STABLE) &&
(arp_table[i].ctime >= ARP_MAXAGE)) {
LWIP_DEBUGF(ETHARP_DEBUG, ("etharp_timer: expired stable entry %u.\n", i));
- arp_table[i].state = ETHARP_STATE_EMPTY;
-#if ARP_QUEUEING
- if (arp_table[i].p != NULL) {
- /* remove any queued packet */
- LWIP_DEBUGF(ETHARP_DEBUG, ("etharp_timer: freeing packet queue %p.\n", i, (void *)(arp_table[i].p)));
- pbuf_free(arp_table[i].p);
- arp_table[i].p = NULL;
- }
-#endif
+ goto empty;
} else if ((arp_table[i].state == ETHARP_STATE_PENDING) &&
(arp_table[i].ctime >= ARP_MAXPENDING)) {
- arp_table[i].state = ETHARP_STATE_EMPTY;
LWIP_DEBUGF(ETHARP_DEBUG, ("etharp_timer: expired pending entry %u.\n", i));
+ empty:
+ arp_table[i].state = ETHARP_STATE_EMPTY;
#if ARP_QUEUEING
if (arp_table[i].p != NULL) {
/* remove any queued packet */
- LWIP_DEBUGF(ETHARP_DEBUG, ("etharp_timer: freeing packet queue %p.\n", i, (void *)(arp_table[i].p)));
+ LWIP_DEBUGF(ETHARP_DEBUG, ("etharp_timer: freeing entry %u, packet queue %p.\n", i, (void *)(arp_table[i].p)));
pbuf_free(arp_table[i].p);
arp_table[i].p = NULL;
}
ethhdr = p->payload;
for (k = 0; k < netif->hwaddr_len; ++k) {
ethhdr->dest.addr[k] = ethaddr->addr[k];
+ ethhdr->src.addr[k] = netif->hwaddr[k];
}
ethhdr->type = htons(ETHTYPE_IP);
LWIP_DEBUGF(ETHARP_DEBUG | DBG_TRACE, ("update_arp_entry: sending queued IP packet.\n"));
/**
- * Responds to ARP requests, updates ARP entries and sends queued IP packets.
+ * Responds to ARP requests to us. Upon ARP replies to us, add entry to cache
+ * send out queued IP packets. Updates cache with snooped address pairs.
*
* Should be called for incoming ARP packets. The pbuf in the argument
* is freed by this function.
{
struct etharp_hdr *hdr;
u8_t i;
+ u8_t for_us;
/* drop short ARP packets */
if (p->tot_len < sizeof(struct etharp_hdr)) {
- LWIP_DEBUGF(ETHARP_DEBUG | DBG_TRACE | 1, ("etharp_arp_input: packet too short (%d/%d)\n", p->tot_len, sizeof(struct etharp_hdr)));
+ LWIP_DEBUGF(ETHARP_DEBUG | DBG_TRACE | 1, ("etharp_arp_input: packet dropped, too short (%d/%d)\n", p->tot_len, sizeof(struct etharp_hdr)));
pbuf_free(p);
return NULL;
}
hdr = p->payload;
+
+ /* this interface is not configured? */
+ if (netif->ip_addr.addr == 0) {
+ for_us = 0;
+ } else {
+ /* ARP packet directed to us? */
+ for_us = ip_addr_cmp(&(hdr->dipaddr), &(netif->ip_addr));
+ }
switch (htons(hdr->opcode)) {
/* ARP request? */
pbuf_free(p);
return NULL;
}
- /* update the ARP cache */
- update_arp_entry(netif, &(hdr->sipaddr), &(hdr->shwaddr), 0);
/* ARP request for our address? */
- if (ip_addr_cmp(&(hdr->dipaddr), &(netif->ip_addr))) {
+ if (for_us) {
LWIP_DEBUGF(ETHARP_DEBUG | DBG_TRACE, ("etharp_arp_input: replying to ARP request for our IP address\n"));
/* re-use pbuf to send ARP reply */
hdr->hwtype = htons(HWTYPE_ETHERNET);
ARPH_HWLEN_SET(hdr, netif->hwaddr_len);
- hdr->proto = htons(ETHTYPE_IP);
+ hdr->proto = htons(ETHTYPE_IP);
ARPH_PROTOLEN_SET(hdr, sizeof(struct ip_addr));
- hdr->ethhdr.type = htons(ETHTYPE_ARP);
+ hdr->ethhdr.type = htons(ETHTYPE_ARP);
/* return ARP reply */
netif->linkoutput(netif, p);
+
+ /* request was not directed to us */
} else {
LWIP_DEBUGF(ETHARP_DEBUG | DBG_TRACE, ("etharp_arp_input: incoming ARP request was not for us.\n"));
}
break;
case ARP_REPLY:
- /* ARP reply. We insert or update the ARP table. */
+ /* ARP reply. We insert or update the ARP table later. */
LWIP_DEBUGF(ETHARP_DEBUG | DBG_TRACE, ("etharp_arp_input: incoming ARP reply\n"));
#if (LWIP_DHCP && DHCP_DOES_ARP_CHECK)
- /* DHCP needs to know about ARP replies */
- dhcp_arp_reply(netif, &hdr->sipaddr);
+ /* DHCP needs to know about ARP replies to our address */
+ if (for_us) dhcp_arp_reply(netif, &hdr->sipaddr);
#endif
- /* ARP reply directed to us? */
- if (ip_addr_cmp(&(hdr->dipaddr), &(netif->ip_addr))) {
- LWIP_DEBUGF(ETHARP_DEBUG | DBG_TRACE, ("etharp_arp_input: incoming ARP reply is for us\n"));
- /* update_the ARP cache, ask to insert */
- update_arp_entry(netif, &(hdr->sipaddr), &(hdr->shwaddr), ARP_INSERT_FLAG);
- /* ARP reply not directed to us */
- } else {
- LWIP_DEBUGF(ETHARP_DEBUG | DBG_TRACE, ("etharp_arp_input: incoming ARP reply is not for us\n"));
- /* update the destination address pair */
- update_arp_entry(netif, &(hdr->sipaddr), &(hdr->shwaddr), 0);
- /* update the destination address pair */
- update_arp_entry(netif, &(hdr->dipaddr), &(hdr->dhwaddr), 0);
- }
break;
default:
LWIP_DEBUGF(ETHARP_DEBUG | DBG_TRACE, ("etharp_arp_input: ARP unknown opcode type %d\n", htons(hdr->opcode)));
break;
}
+ /* add or update entries in the ARP cache */
+ if (for_us) {
+ /* insert IP address in ARP cache (assume requester wants to talk to us)
+ * we might even send out a queued packet to this host */
+ update_arp_entry(netif, &(hdr->sipaddr), &(hdr->shwaddr), ARP_INSERT_FLAG);
+ /* request was not directed to us, but snoop anyway */
+ } else {
+ /* update or insert the source IP address in the cache */
+ update_arp_entry(netif, &(hdr->sipaddr), &(hdr->shwaddr), 0);
+ /* update or insert the destination IP address pair in the cache */
+ update_arp_entry(netif, &(hdr->dipaddr), &(hdr->dhwaddr), 0);
+ }
/* free ARP packet */
pbuf_free(p);
p = NULL;
* returned, ready to be sent.
*
* If ARP does not have the Ethernet address in cache the packet is
- * queued and a ARP request is sent (on a best-effort basis). This
- * ARP request is returned as a pbuf, which should be sent by the
- * caller.
+ * queued (if enabled and space available) and a ARP request is sent.
+ * This ARP request is returned as a pbuf, which should be sent by
+ * the caller.
*
* If ARP failed to allocate resources, NULL is returned.
*
* @param ipaddr The IP address of the packet destination.
* @param pbuf The pbuf(s) containing the IP packet to be sent.
*
- * @return If non-NULL, a packet ready to be sent.
+ * @return If non-NULL, a packet ready to be sent by caller.
+ *
*/
struct pbuf *
etharp_output(struct netif *netif, struct ip_addr *ipaddr, struct pbuf *q)
/* The pbuf_header() call shouldn't fail, and we'll just bail
out if it does.. */
LWIP_DEBUGF(ETHARP_DEBUG | DBG_TRACE | 2, ("etharp_output: could not allocate room for header.\n"));
-#ifdef LINK_STATS
- ++lwip_stats.link.lenerr;
-#endif /* LINK_STATS */
+ LINK_STATS_INC(link.lenerr);
return NULL;
}
/* assume unresolved Ethernet address */
dest = NULL;
/* Construct Ethernet header. Start with looking up deciding which
- MAC address to use as a destination address. Broadcasts and
- multicasts are special, all other addresses are looked up in the
- ARP table. */
+ MAC address to use as a destination address. Broadcasts and
+ multicasts are special, all other addresses are looked up in the
+ ARP table. */
/* destination IP address is an IP broadcast address? */
if (ip_addr_isany(ipaddr) ||
else if (ip_addr_ismulticast(ipaddr)) {
/* Hash IP multicast address to MAC address. */
mcastaddr.addr[0] = 0x01;
- mcastaddr.addr[1] = 0x0;
+ mcastaddr.addr[1] = 0x00;
mcastaddr.addr[2] = 0x5e;
mcastaddr.addr[3] = ip4_addr2(ipaddr) & 0x7f;
mcastaddr.addr[4] = ip4_addr3(ipaddr);
}
/* Ethernet address for IP destination address is in ARP cache? */
- for(i = 0; i < ARP_TABLE_SIZE; ++i) {
+ for (i = 0; i < ARP_TABLE_SIZE; ++i) {
/* match found? */
if (arp_table[i].state == ETHARP_STATE_STABLE &&
ip_addr_cmp(ipaddr, &arp_table[i].ipaddr)) {
/* could not find the destination Ethernet address in ARP cache? */
if (dest == NULL) {
/* ARP query for the IP address, submit this IP packet for queueing */
+ /* TODO: How do we handle netif->ipaddr == ipaddr? */
etharp_query(netif, ipaddr, q);
/* return nothing */
return NULL;
LWIP_DEBUGF(ETHARP_DEBUG | DBG_TRACE, ("etharp_query: sending ARP request.\n"));
hdr = p->payload;
hdr->opcode = htons(ARP_REQUEST);
- for(j = 0; j < netif->hwaddr_len; ++j)
+ for (j = 0; j < netif->hwaddr_len; ++j)
{
- hdr->dhwaddr.addr[j] = 0x00;
hdr->shwaddr.addr[j] = srcaddr->addr[j];
+ /* the hardware address is what we ask for, in
+ * a request it is a don't-care, we use 0's */
+ hdr->dhwaddr.addr[j] = 0x00;
}
ip_addr_set(&(hdr->dipaddr), ipaddr);
ip_addr_set(&(hdr->sipaddr), &(netif->ip_addr));
hdr->proto = htons(ETHTYPE_IP);
ARPH_PROTOLEN_SET(hdr, sizeof(struct ip_addr));
- for(j = 0; j < netif->hwaddr_len; ++j)
+ for (j = 0; j < netif->hwaddr_len; ++j)
{
hdr->ethhdr.dest.addr[j] = 0xff;
hdr->ethhdr.src.addr[j] = srcaddr->addr[j];
projects / pes-rpp / rpp-lwip.git / blobdiff