[1041] in linux-net channel archive
Permanent ARP entries broken ?
daemon@ATHENA.MIT.EDU (Craig Schlenter)
Mon Sep 4 18:41:56 1995
Date: Mon, 4 Sep 1995 10:10:25 +0200 (GMT+0200)
From: Craig Schlenter <schz@kidd.co.za>
To: linux-net@vger.rutgers.edu
Hi
Should permanent entries in the ARP cache be changed by incoming arp requests
? Currently arp.c overwrites the existing entry. The patch below fixes the
problem ...
If the current behaviour is considered 'correct', could we add another
entry type, say VERY_PERMANENT, that will not be overwritten ?
If there are no complaints, I'll submit this for 1.3.24.
Thank you,
--Craig Schlenter
cschle@paradigm.co.za <- preferred
schz@kidd.co.za
--- v1.3.22/net/ipv4/arp.c Fri Sep 1 19:50:01 1995
+++ linux/net/ipv4/arp.c Sat Sep 2 17:00:52 1995
@@ -42,7 +42,9 @@
* Mike Shaver : RFC1122 checks.
* Jonathan Naylor : Only lookup the hardware address for
* the correct hardware type.
- * Germano Caronni : Assorted subtle races
+ * Germano Caronni : Assorted subtle races.
+ * Craig Schlenter : Don't modify permanent entry
+ * during arp_rcv.
*/
/* RFC1122 Status:
@@ -93,9 +95,9 @@
/*
* This structure defines the ARP mapping cache. As long as we make changes
- * in this structure, we keep interrupts of. But normally we can copy the
- * hardware address and the device pointer in a local variable and then make
- * any "long calls" to send a packet out.
+ * in this structure, we keep interrupts off. But normally we can copy the
+ * hardware address and the device pointer in a local variable and then
+ * make any "long calls" to send a packet out.
*/
struct arp_table
@@ -811,11 +813,13 @@
if(entry)
{
/*
- * Entry found; update it.
+ * Entry found; update it only if it is not a permanent entry.
*/
- memcpy(entry->ha, sha, hlen);
- entry->hlen = hlen;
- entry->last_used = jiffies;
+ if (!(entry->flags & ATF_PERM)) {
+ memcpy(entry->ha, sha, hlen);
+ entry->hlen = hlen;
+ entry->last_used = jiffies;
+ }
if (!(entry->flags & ATF_COM))
{
/*
