Reduce incidence of trying to transmit to new neighbors to conserve neighbor table

src/net/arp.c

@@ -234,7 +234,7 @@ static int arp_rx ( struct io_buffer *iobuf, struct net_device *netdev,
 		goto done;
 	
 	/* Create new ARP table entry if necessary */
-	if ( ! merge ) {
+	if ( ( arphdr->ar_op == htons ( ARPOP_REPLY ) ) && (! merge ) ) {
 		arp = &arp_table[next_new_arp_entry++ % NUM_ARP_ENTRIES];
 		arp->ll_protocol = ll_protocol;
 		arp->net_protocol = net_protocol;

src/net/icmp.c

@@ -69,11 +69,12 @@ static int icmp_rx ( struct io_buffer *iobuf, struct sockaddr_tcpip *st_src,
 	}
 
 	/* We respond only to pings */
-	if ( icmp->type != ICMP_ECHO_REQUEST ) {
+        /* Don't bother responding to ping, it's above what most do and the neighbor table is preciously small here */
+	/* if ( icmp->type != ICMP_ECHO_REQUEST ) { */
 		DBG ( "ICMP ignoring type %d\n", icmp->type );
 		rc = 0;
 		goto done;
-	}
+	/* } */
 
 	DBG ( "ICMP responding to ping\n" );
 

src/net/tcp.c

@@ -1120,7 +1120,8 @@ static int tcp_rx ( struct io_buffer *iobuf,
 
 	/* If no connection was found, send RST */
 	if ( ! tcp ) {
-		tcp_xmit_reset ( tcp, st_src, tcphdr );
+		/* Transmitting RST costs precious neighbor table space, and this is no worse than most boot roms */
+		/* tcp_xmit_reset ( tcp, st_src, tcphdr ); */
 		rc = -ENOTCONN;
 		goto discard;
 	}