Fix RIPv1 subnet bugs

Submitted by:	jonny@jonny.eng.br (Joao Carlos Mendes Luis)
Obtained from:	http://www.geocrawler.com/archives/3/372/2002/10/0/9918592/

1 files changed, 301 insertions, 0 deletions

diff --git a/net/zebra-pj/files/patch-ripd b/net/zebra-pj/files/patch-ripd
new file mode 100644
index 00000000000..4178aaac23c
--- /dev/null
+++ b/net/zebra-pj/files/patch-ripd
@@ -0,0 +1,301 @@
+--- lib/if.c.orig	Fri Jun 21 23:49:50 2002
++++ lib/if.c	Mon Oct 14 17:25:42 2002
+@@ -553,6 +553,65 @@
+   return NULL;
+ }
+ 
++/* Find the IPv4 address on our side that will be used when packets
++   are sent to dst. */
++struct connected *
++connected_lookup_address (struct interface *ifp, struct in_addr dst)
++{
++  struct prefix addr;
++  struct prefix best;
++  listnode cnode;
++  struct prefix *p;
++  struct connected *c;
++  struct connected *match;
++
++  /* Zero structures - get rid of rubbish from stack */
++  memset(&addr, 0, sizeof(addr));
++  memset(&best, 0, sizeof(best));
++
++  addr.family = AF_INET;
++  addr.u.prefix4 = dst;
++  addr.prefixlen = IPV4_MAX_BITLEN;
++
++  match = NULL;
++
++  for (cnode = listhead (ifp->connected); cnode; nextnode (cnode))
++    {
++      c = getdata (cnode);
++
++      if (if_is_pointopoint (ifp))
++	{
++	  p = c->address;
++
++	  if (p && p->family == AF_INET)
++	    {
++#ifdef OLD_RIB	 /* PTP  links are conventionally identified 
++		    by the address of the far end - MAG */
++	      if (IPV4_ADDR_SAME (&p->u.prefix4, &dst))
++		return c;
++#endif
++	      p = c->destination;
++	      if (p && IPV4_ADDR_SAME (&p->u.prefix4, &dst))
++		return c;
++	    }
++	}
++      else
++	{
++	  p = c->address;
++
++	  if (p->family == AF_INET)
++	    {
++	      if (prefix_match (p, &addr) && p->prefixlen > best.prefixlen)
++		{
++		  best = *p;
++		  match = c;
++		}
++	    }
++	}
++    }
++  return match;
++}
++
+ /* Check the connected information is PtP style or not.  */
+ int
+ ifc_pointopoint (struct connected *ifc)
+--- ./lib/if.h.orig	Fri Jun 21 23:49:50 2002
++++ ./lib/if.h	Mon Oct 14 17:25:42 2002
+@@ -202,6 +202,7 @@
+ void connected_free (struct connected *);
+ void connected_add (struct interface *, struct connected *);
+ struct connected  *connected_delete_by_prefix (struct interface *, struct prefix *);
++struct connected  *connected_lookup_address (struct interface *, struct in_addr);
+ int ifc_pointopoint (struct connected *);
+ 
+ #ifndef HAVE_IF_NAMETOINDEX
+--- ./ripd/ripd.c.orig	Mon Jul  1 02:57:22 2002
++++ ./ripd/ripd.c	Tue Oct 15 10:02:11 2002
+@@ -55,8 +55,8 @@
+ /* Prototypes. */
+ void rip_event (enum rip_event, int);
+ 
+-void rip_output_process (struct interface *, struct sockaddr_in *, 
+-			 int, u_char);
++void rip_output_process (struct interface *, struct prefix *,
++			 struct sockaddr_in *, int, u_char);
+ 
+ /* RIP output routes type. */
+ enum
+@@ -955,7 +955,14 @@
+ {
+   caddr_t lim;
+   struct rte *rte;
++  struct prefix_ipv4 ifaddr;
++  struct prefix_ipv4 ifaddrclass;
++  struct connected *c;
++  int subnetted;
+       
++  /* We don't know yet. */
++  subnetted = -1;
++
+   /* The Response must be ignored if it is not from the RIP
+      port. (RFC2453 - Sec. 3.9.2)*/
+   if (ntohs (from->sin_port) != RIP_PORT_DEFAULT) 
+@@ -1108,23 +1115,51 @@
+ 	{
+ 	  u_int32_t destination;
+ 
+-	  destination = ntohl (rte->prefix.s_addr);
+-
+-	  if (destination & 0xff) 
++	  if (subnetted == -1)
+ 	    {
+-	      masklen2ip (32, &rte->mask);
++	      c = connected_lookup_address (ifp, from->sin_addr);
++	      if (c != NULL)
++		{
++		  memcpy (&ifaddr, c->address, sizeof (struct prefix_ipv4));
++		  memcpy (&ifaddrclass, &ifaddr, sizeof (struct prefix_ipv4));
++		  apply_classful_mask_ipv4 (&ifaddrclass);
++		  subnetted = 0;
++		  if (ifaddr.prefixlen > ifaddrclass.prefixlen)
++		    subnetted = 1;
++		}
+ 	    }
+-	  else if ((destination & 0xff00) || IN_CLASSC (destination)) 
+-	    {
++
++	  destination = ntohl (rte->prefix.s_addr);
++
++	  if (IN_CLASSA (destination))
++	      masklen2ip (8, &rte->mask);
++	  else if (IN_CLASSB (destination))
++	      masklen2ip (16, &rte->mask);
++	  else if (IN_CLASSC (destination))
+ 	      masklen2ip (24, &rte->mask);
++
++	  if (subnetted == 1)
++	    masklen2ip (ifaddrclass.prefixlen,
++			(struct in_addr *) &destination);
++	  if ((subnetted == 1) && ((rte->prefix.s_addr & destination) ==
++	      ifaddrclass.prefix.s_addr))
++	    {
++	      masklen2ip (ifaddr.prefixlen, &rte->mask);
++	      if ((rte->prefix.s_addr & rte->mask.s_addr) != rte->prefix.s_addr)
++		masklen2ip (32, &rte->mask);
++	      if (IS_RIP_DEBUG_EVENT)
++		zlog_info ("Subnetted route %s", inet_ntoa (rte->prefix));
+ 	    }
+-	  else if ((destination & 0xff0000) || IN_CLASSB (destination)) 
++	  else
+ 	    {
+-	      masklen2ip (16, &rte->mask);
++	      if ((rte->prefix.s_addr & rte->mask.s_addr) != rte->prefix.s_addr)
++		continue;
+ 	    }
+-	  else 
++
++	  if (IS_RIP_DEBUG_EVENT)
+ 	    {
+-	      masklen2ip (8, &rte->mask);
++	      zlog_info ("Resultant route %s", inet_ntoa (rte->prefix));
++	      zlog_info ("Resultant mask %s", inet_ntoa (rte->mask));
+ 	    }
+ 	}
+ 
+@@ -1353,7 +1388,7 @@
+       ntohl (rte->metric) == RIP_METRIC_INFINITY)
+     {	
+       /* All route with split horizon */
+-      rip_output_process (ifp, from, rip_all_route, packet->version);
++      rip_output_process (ifp, NULL, from, rip_all_route, packet->version);
+     }
+   else
+     {
+@@ -1884,8 +1919,8 @@
+ 
+ /* Send update to the ifp or spcified neighbor. */
+ void
+-rip_output_process (struct interface *ifp, struct sockaddr_in *to,
+-		    int route_type, u_char version)
++rip_output_process (struct interface *ifp, struct prefix *ifaddr,
++		    struct sockaddr_in *to, int route_type, u_char version)
+ {
+   int ret;
+   struct stream *s;
+@@ -1894,8 +1929,11 @@
+   struct rip_interface *ri;
+   struct prefix_ipv4 *p;
+   struct prefix_ipv4 classfull;
++  struct prefix_ipv4 ifaddrclass;
++  struct connected *c;
+   int num;
+   int rtemax;
++  int subnetted;
+ 
+   /* Logging output event. */
+   if (IS_RIP_DEBUG_EVENT)
+@@ -1946,29 +1984,60 @@
+          rtemax -=1;
+     }
+ 
++  if (version == RIPv1)
++    {
++      if (ifaddr == NULL)
++	{
++	  c = connected_lookup_address (ifp, to->sin_addr);
++	  if (c != NULL)
++	    ifaddr = c->address;
++	}
++      if (ifaddr == NULL)
++	{
++	  zlog_warn ("cannot find source address for packets to neighbor %s",
++		     inet_ntoa (to->sin_addr));
++	  return;
++	}
++      memcpy (&ifaddrclass, ifaddr, sizeof (struct prefix_ipv4));
++      apply_classful_mask_ipv4 (&ifaddrclass);
++      subnetted = 0;
++      if (ifaddr->prefixlen > ifaddrclass.prefixlen)
++	subnetted = 1;
++    }
++
+   for (rp = route_top (rip->table); rp; rp = route_next (rp))
+     if ((rinfo = rp->info) != NULL)
+       {
+-	/* Some inheritance stuff:                                          */
+-	/* Before we process with ipv4 prefix we should mask it             */
+-	/* with Classful mask if we send RIPv1 packet.That's because        */
+-	/* user could set non-classful mask or we could get it by RIPv2     */
+-	/* or other protocol. checked with Cisco's way of life :)           */
++	/* For RIPv1, if we are subnetted, output subnets in our network    */
++	/* that have the same mask as the output "interface". For other     */
++	/* networks, only the classfull version is output.                  */
+ 	
+ 	if (version == RIPv1)
+ 	  {
+-	    memcpy (&classfull, &rp->p, sizeof (struct prefix_ipv4));
++	    p = (struct prefix_ipv4 *) &rp->p;
+ 
+ 	    if (IS_RIP_DEBUG_PACKET)
+-	      zlog_info("%s/%d before RIPv1 mask check ",
+-			inet_ntoa (classfull.prefix), classfull.prefixlen);
+-
+-	    apply_classful_mask_ipv4 (&classfull);
+-	    p = &classfull;
++	      zlog_info("RIPv1 mask check, %s/%d considered for output",
++			inet_ntoa (rp->p.u.prefix4), rp->p.prefixlen);
+ 
++	    if (subnetted &&
++		prefix_match ((struct prefix *) &ifaddrclass, &rp->p))
++	      {
++		if ((ifaddr->prefixlen != rp->p.prefixlen) &&
++		    (rp->p.prefixlen != 32))
++		  continue;
++	      }
++	    else
++	      {
++		memcpy (&classfull, &rp->p, sizeof(struct prefix_ipv4));
++		apply_classful_mask_ipv4(&classfull);
++		if (rp->p.u.prefix4.s_addr != 0 &&
++		    classfull.prefixlen != rp->p.prefixlen)
++		  continue;
++	      }
+ 	    if (IS_RIP_DEBUG_PACKET)
+-	      zlog_info("%s/%d after RIPv1 mask check",
+-			inet_ntoa (p->prefix), p->prefixlen);
++	      zlog_info("RIPv1 mask check, %s/%d made it through",
++			inet_ntoa (rp->p.u.prefix4), rp->p.prefixlen);
+ 	  }
+ 	else 
+ 	  p = (struct prefix_ipv4 *) &rp->p;
+@@ -2109,7 +2178,7 @@
+       if (IS_RIP_DEBUG_EVENT)
+ 	zlog_info ("multicast announce on %s ", ifp->name);
+ 
+-      rip_output_process (ifp, NULL, route_type, version);
++      rip_output_process (ifp, NULL, NULL, route_type, version);
+       return;
+     }
+ 
+@@ -2136,7 +2205,8 @@
+ 			   if_is_pointopoint (ifp) ? "unicast" : "broadcast",
+ 			   inet_ntoa (to.sin_addr), ifp->name);
+ 
+-	      rip_output_process (ifp, &to, route_type, version);
++	      rip_output_process (ifp, connected->address, &to, route_type,
++				  version);
+ 	    }
+ 	}
+     }
+@@ -2224,7 +2294,7 @@
+ 	to.sin_port = htons (RIP_PORT_DEFAULT);
+ 
+ 	/* RIP version is rip's configuration. */
+-	rip_output_process (ifp, &to, route_type, rip->version);
++	rip_output_process (ifp, NULL, &to, route_type, rip->version);
+       }
+ }