From 2d6c314c64c0c8e6c51f10dc5ea4970f1398c7b7 Mon Sep 17 00:00:00 2001
From: likewise <likewise>
Date: Thu, 22 Jan 2004 20:41:22 +0000
Subject: [PATCH] Corrected some comments. Strongened assertions. Preparation
 for gratuitous ARP sending.

---
 src/netif/etharp.c | 31 ++++++++++++++++++-------------
 1 file changed, 18 insertions(+), 13 deletions(-)

diff --git a/src/netif/etharp.c b/src/netif/etharp.c
index b1417898..b3e04483 100644
--- a/src/netif/etharp.c
+++ b/src/netif/etharp.c
@@ -372,20 +372,22 @@ update_arp_entry(struct netif *netif, struct ip_addr *ipaddr, struct eth_addr *e
 #if ARP_QUEUEING
         /* get the first packet on the queue (if any) */
         p = arp_table[i].p;
-        /* queued packet present? */
+        /* (another) queued packet present? */
         while (p != NULL) {
           struct pbuf *q, *n;
           /* search for second packet on queue (n) */
           q = p;
           while (q->tot_len > q->len) {
-          	/* proceed to next pbuf of this packet */
-          	LWIP_ASSERT("q->next ! NULL", q->next != NULL);
-          	q = q->next;
+            LWIP_ASSERT("q->next != NULL (while q->tot_len > q->len)", q->next != NULL);
+            /* proceed to next pbuf of this packet */
+            q = q->next;
           }
-          /* { q = last pbuf of first packet, q->tot_len = q->len } */
+          /* { q = last pbuf of this packet, q->tot_len == q->len } */
+          LWIP_ASSERT("q->tot_len == q->len", q->tot_len == q->len);
+          /* remember next packet on queue */
           n = q->next;
-          /* { n = first pbuf of 2nd packet, or NULL if no 2nd packet } */
-          /* terminate the first packet pbuf chain */
+          /* { n = first pbuf of next packet, or NULL if no next packet } */
+          /* terminate this packet pbuf chain */
           q->next = NULL;
           /* fill-in Ethernet header */
           ethhdr = p->payload;
@@ -394,7 +396,7 @@ update_arp_entry(struct netif *netif, struct ip_addr *ipaddr, struct eth_addr *e
             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 %p.\n",(void *)p));
+          LWIP_DEBUGF(ETHARP_DEBUG | DBG_TRACE, ("update_arp_entry: sending queued IP packet %p.\n", (void *)p));
           /* send the queued IP packet */
           netif->linkoutput(netif, p);
           /* free the queued IP packet */
@@ -405,10 +407,11 @@ update_arp_entry(struct netif *netif, struct ip_addr *ipaddr, struct eth_addr *e
         /* NULL attached buffer*/
         arp_table[i].p = NULL;
 #endif
+        /* IP addresses should only occur once in the ARP entry, we are done */
         return NULL;
       }
-    } /* if */
-  } /* for */
+    } /* if STABLE */
+  } /* for all ARP entries */
 
   /* no matching ARP entry was found */
   LWIP_ASSERT("update_arp_entry: i == ARP_TABLE_SIZE", i == ARP_TABLE_SIZE);
@@ -520,6 +523,8 @@ etharp_arp_input(struct netif *netif, struct eth_addr *ethaddr, struct pbuf *p)
     /* ARP packet directed to us? */
     for_us = ip_addr_cmp(&(hdr->dipaddr), &(netif->ip_addr));
   }
+  
+  /* first, let's answer */
 
   switch (htons(hdr->opcode)) {
   /* ARP request? */
@@ -545,7 +550,7 @@ etharp_arp_input(struct netif *netif, struct eth_addr *ethaddr, struct pbuf *p)
       ip_addr_set(&(hdr->dipaddr), &(hdr->sipaddr));
       ip_addr_set(&(hdr->sipaddr), &(netif->ip_addr));
 
-      for(i = 0; i < netif->hwaddr_len; ++i) {
+      for (i = 0; i < netif->hwaddr_len; ++i) {
         hdr->dhwaddr.addr[i] = hdr->shwaddr.addr[i];
         hdr->shwaddr.addr[i] = ethaddr->addr[i];
         hdr->ethhdr.dest.addr[i] = hdr->dhwaddr.addr[i];
@@ -571,7 +576,7 @@ etharp_arp_input(struct netif *netif, struct eth_addr *ethaddr, struct pbuf *p)
     /* 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 to our address */
+    /* DHCP wants to know about ARP replies to our wanna-have-address */
     if (for_us) dhcp_arp_reply(netif, &hdr->sipaddr);
 #endif
     break;
@@ -584,7 +589,7 @@ etharp_arp_input(struct netif *netif, struct eth_addr *ethaddr, struct pbuf *p)
     /* 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 */
+  /* request was not directed to us, but snoop for updates anyway */
   } else {
     /* update or insert the source IP address in the cache */
     update_arp_entry(netif, &(hdr->sipaddr), &(hdr->shwaddr), 0);