dhcp/dhcp-improved-xid.patch

diff -up dhcp-4.3.0a1/client/dhclient.c.improved-xid dhcp-4.3.0a1/client/dhclient.c
--- dhcp-4.3.0a1/client/dhclient.c.improved-xid	2013-12-20 13:29:41.836260810 +0100
+++ dhcp-4.3.0a1/client/dhclient.c	2013-12-20 13:29:41.843260713 +0100
@@ -894,6 +894,26 @@ main(int argc, char **argv) {
 		}
 	}
 
+	/* We create a backup seed before rediscovering interfaces in order to
+	   have a seed built using all of the available interfaces
+	   It's interesting if required interfaces doesn't let us defined
+	   a really unique seed due to a lack of valid HW addr later
+	   (this is the case with DHCP over IB)
+	   We only use the last device as using a sum could broke the
+	   uniqueness of the seed among multiple nodes
+	 */
+	unsigned backup_seed = 0;
+	for (ip = interfaces; ip; ip = ip -> next) {
+		int junk;
+		if ( ip -> hw_address.hlen <= sizeof seed )
+		  continue;
+		memcpy (&junk,
+			&ip -> hw_address.hbuf [ip -> hw_address.hlen -
+						sizeof seed], sizeof seed);
+		backup_seed = junk;
+	}
+
+
 	/* At this point, all the interfaces that the script thinks
 	   are relevant should be running, so now we once again call
 	   discover_interfaces(), and this time ask it to actually set
@@ -908,14 +928,36 @@ main(int argc, char **argv) {
 	   Not much entropy, but we're booting, so we're not likely to
 	   find anything better. */
 	seed = 0;
+	int seed_flag = 0;
 	for (ip = interfaces; ip; ip = ip->next) {
 		int junk;
+		if ( ip -> hw_address.hlen <= sizeof seed )
+		  continue;
 		memcpy(&junk,
 		       &ip->hw_address.hbuf[ip->hw_address.hlen -
 					    sizeof seed], sizeof seed);
 		seed += junk;
+		seed_flag = 1;
 	}
-	srandom(seed + cur_time + (unsigned)getpid());
+	if ( seed_flag == 0 ) {
+		if ( backup_seed != 0 ) {
+		  seed = backup_seed;
+		  log_info ("xid: rand init seed (0x%x) built using all"
+			    " available interfaces",seed);
+		}
+		else {
+		  seed = cur_time^((unsigned) gethostid()) ;
+		  log_info ("xid: warning: no netdev with useable HWADDR found"
+			    " for seed's uniqueness enforcement");
+		  log_info ("xid: rand init seed (0x%x) built using gethostid",
+			    seed);
+		}
+		/* we only use seed and no current time as a broadcast reply */
+		/* will certainly be used by the hwaddrless interface */
+		srandom(seed);
+	}
+	else
+	        srandom(seed + cur_time + (unsigned)getpid());
 
 	/* Setup specific Infiniband options */
 	for (ip = interfaces; ip; ip = ip->next) {
@@ -1460,7 +1502,7 @@ void dhcpack (packet)
 		return;
 	}
 
-	log_info ("DHCPACK from %s", piaddr (packet -> client_addr));
+	log_info ("DHCPACK from %s (xid=0x%x)", piaddr (packet -> client_addr), ntohl(client -> xid));
 
 	lease = packet_to_lease (packet, client);
 	if (!lease) {
@@ -2171,7 +2213,7 @@ void dhcpnak (packet)
 		return;
 	}
 
-	log_info ("DHCPNAK from %s", piaddr (packet -> client_addr));
+	log_info ("DHCPNAK from %s (xid=0x%x)", piaddr (packet -> client_addr), ntohl(client -> xid));
 
 	if (!client -> active) {
 #if defined (DEBUG)
@@ -2298,10 +2340,10 @@ void send_discover (cpp)
 		client -> packet.secs = htons (65535);
 	client -> secs = client -> packet.secs;
 
-	log_info ("DHCPDISCOVER on %s to %s port %d interval %ld",
+	log_info ("DHCPDISCOVER on %s to %s port %d interval %ld (xid=0x%x)",
 	      client -> name ? client -> name : client -> interface -> name,
 	      inet_ntoa (sockaddr_broadcast.sin_addr),
-	      ntohs (sockaddr_broadcast.sin_port), (long)(client -> interval));
+	      ntohs (sockaddr_broadcast.sin_port), (long)(client -> interval), ntohl(client -> xid));
 
 	/* Send out a packet. */
 	result = send_packet(client->interface, NULL, &client->packet,
@@ -2570,10 +2612,10 @@ void send_request (cpp)
 			client -> packet.secs = htons (65535);
 	}
 
-	log_info ("DHCPREQUEST on %s to %s port %d",
+	log_info ("DHCPREQUEST on %s to %s port %d (xid=0x%x)",
 	      client -> name ? client -> name : client -> interface -> name,
 	      inet_ntoa (destination.sin_addr),
-	      ntohs (destination.sin_port));
+	      ntohs (destination.sin_port), ntohl(client -> xid));
 
 	if (destination.sin_addr.s_addr != INADDR_BROADCAST &&
 	    fallback_interface) {
@@ -2613,10 +2655,10 @@ void send_decline (cpp)
 
 	int result;
 
-	log_info ("DHCPDECLINE on %s to %s port %d",
+	log_info ("DHCPDECLINE on %s to %s port %d (xid=0x%x)",
 	      client->name ? client->name : client->interface->name,
 	      inet_ntoa(sockaddr_broadcast.sin_addr),
-	      ntohs(sockaddr_broadcast.sin_port));
+	      ntohs(sockaddr_broadcast.sin_port), ntohl(client -> xid));
 
 	/* Send out a packet. */
 	result = send_packet(client->interface, NULL, &client->packet,
@@ -2659,10 +2701,10 @@ void send_release (cpp)
 		return;
 	}
 
-	log_info ("DHCPRELEASE on %s to %s port %d",
+	log_info ("DHCPRELEASE on %s to %s port %d (xid=0x%x)",
 	      client -> name ? client -> name : client -> interface -> name,
 	      inet_ntoa (destination.sin_addr),
-	      ntohs (destination.sin_port));
+	      ntohs (destination.sin_port), ntohl(client -> xid));
 
 	if (fallback_interface) {
 		result = send_packet(fallback_interface, NULL, &client->packet,