[PtP over ethernet] New peer flag allows much more addressing flexibility

2006-12-12 Andrew J. Schorr <ajschorr@alumni.princeton.edu>

	* if.h: (struct connected) Add new ZEBRA_IFA_PEER flag indicating
	  whether a peer address has been configured.  Comment now shows
	  the new interpretation of the destination addr: if ZEBRA_IFA_PEER
	  is set, then it must contain the destination address, otherwise
	  it may contain the broadcast address or be NULL.
	  (CONNECTED_DEST_HOST,CONNECTED_POINTOPOINT_HOST) Remove obsolete
	  macros that were specific to IPv4 and not fully general.
	  (CONNECTED_PEER) New macro to check ZEBRA_IFA_PEER flag.
	  (CONNECTED_PREFIX) New macro giving the prefix to insert into
	  the RIB: if CONNECTED_PEER, then use the destination (peer) address,
	  else use the address field.
	  (CONNECTED_ID) New macro to come up with an identifying address
	  for the struct connected.
	* if.c: (if_lookup_address, connected_lookup_address) Streamline
	  logic with new CONNECTED_PREFIX macro.
	* prefix.h: (PREFIX_COPY_IPV4, PREFIX_COPY_IPV6) New macros
	  for better performance than the general prefix_copy function.
	* zclient.c: (zebra_interface_address_read) For non-null destination
	  addresses, set prefixlen to equal the address prefixlen.  This
	  is needed to get the new CONNECTED_PREFIX macro to work properly.
	* connected.c: (connected_up_ipv4, connected_down_ipv4,
	  connected_up_ipv6, connected_down_ipv6) Simplify logic using the
	  new CONNECTED_PREFIX macro.
	  (connected_add_ipv4) Set prefixlen in destination addresses (required
	  by the CONNECTED_PREFIX macro).  Use CONNECTED_PEER macro instead
	  of testing for IFF_POINTOPOINT.  Delete invalid warning message.
	  Warn about cases where the ZEBRA_IFA_PEER is set but no
	  destination address has been supplied (and turn off the flag).
	  (connected_add_ipv6) Add new flags argument so callers may set
	  the ZEBRA_IFA_PEER flag.  If peer/broadcast address satisfies
	  IN6_IS_ADDR_UNSPECIFIED, then reject it with a warning.
	  Set prefixlen in destination address so CONNECTED_PREFIX will work.
	* connected.h: (connected_add_ipv6) Add new flags argument so
	  callers may set the ZEBRA_IFA_PEER flag.
	* interface.c: (connected_dump_vty) Use CONNECTED_PEER macro
	  to decide whether the destination address is a peer or broadcast
	  address (instead of checking IFF_BROADCAST and IFF_POINTOPOINT).
	* if_ioctl.c: (if_getaddrs) Instead of setting a peer address
	  only when the IFF_POINTOPOINT is set, we now accept a peer
	  address whenever it is available and not the same as the local
	  address.  Otherwise (no peer address assigned), we check
	  for a broadcast address (regardless of the IFF_BROADCAST flag).
	  And must now pass a flags value of ZEBRA_IFA_PEER to
	  connected_add_ipv4 when a peer address is assigned.
	  The same new logic is used with the IPv6 code as well (and we
	  pass the new flags argument to connected_add_ipv6).
	  (if_get_addr) Do not bother to check IFF_POINTOPOINT: just
	  issue the SIOCGIFDSTADDR ioctl and see if we get back
	  a peer address not matching the local address (and set
	  the ZEBRA_IFA_PEER in that case).  If there's no peer address,
	  try to grab SIOCGIFBRDADDR regardless of whether IFF_BROADCAST is set.
	* if_ioctl_solaris.c: (if_get_addr) Just try the SIOCGLIFDSTADDR ioctl
	  without bothering to check the IFF_POINTOPOINT flag.  And if
	  no peer address was found, just try the SIOCGLIFBRDADDR ioctl
	  without checking the IFF_BROADCAST flag.  Call connected_add_ipv4
	  and connected_add_ipv6 with appropriate flags.
	* if_proc.c: (ifaddr_proc_ipv6) Must pass new flags argument to
	  connected_add_ipv6.
	* kernel_socket.c: (ifam_read) Must pass new flags argument to
	  connected_add_ipv6.
	* rt_netlink.c: (netlink_interface_addr) Copy logic from iproute2
	  to determine local and possible peer address (so there's no longer
	  a test for IFF_POINTOPOINT).  Set ZEBRA_IFA_PEER flag appropriately.
	  Pass new flags argument to connected_add_ipv6.
	  (netlink_address) Test !CONNECTED_PEER instead of if_is_broadcast
	  to determine whether the connected destination address is a
	  broadcast address.
	* bgp_nexthop.c: (bgp_connected_add, bgp_connected_delete)
	  Simplify logic by using new CONNECTED_PREFIX macro.
	* ospf_interface.c: (ospf_if_is_configured, ospf_if_lookup_by_prefix,
	  ospf_if_lookup_recv_if) Simplify logic using new CONNECTED_PREFIX
	  macro.
	* ospf_lsa.c: (lsa_link_ptop_set) Using the new CONNECTED_PREFIX
	  macro, both options collapse into the same code.
	* ospf_snmp.c: (ospf_snmp_if_update) Simplify logic using new
	  CONNECTED_ID macro.
	  (ospf_snmp_is_if_have_addr) Simplify logic using new CONNECTED_PREFIX
	  macro.
	* ospf_vty.c: (show_ip_ospf_interface_sub) Use new CONNECTED_PEER macro
	  instead of testing the IFF_POINTOPOINT flag.
	* ospfd.c: (ospf_network_match_iface) Use new CONNECTED_PEER macro
	  instead of testing with if_is_pointopoint.  And add commented-out
	  code to implement alternative (in my opinion) more elegant behavior
	  that has no special-case treatment for PtP addresses.
	  (ospf_network_run) Use new CONNECTED_ID macro to simplify logic.
	* rip_interface.c: (rip_interface_multicast_set) Use new CONNECTED_ID
	  macro to simplify logic.
	  (rip_request_interface_send) Fix minor bug: ipv4_broadcast_addr does
	  not give a useful result if prefixlen is 32 (we require a peer
	  address in such cases).
	* ripd.c: (rip_update_interface) Fix same bug as above.

5 files changed, 66 insertions, 50 deletions

diff --git a/lib/ChangeLog b/lib/ChangeLog
index f076e2f0..914cc5e8 100644
--- a/lib/ChangeLog
+++ b/lib/ChangeLog
@@ -1,3 +1,26 @@
+2006-12-12 Andrew J. Schorr <ajschorr@alumni.princeton.edu>
+
+	* if.h: (struct connected) Add new ZEBRA_IFA_PEER flag indicating
+	  whether a peer address has been configured.  Comment now shows
+	  the new interpretation of the destination addr: if ZEBRA_IFA_PEER
+	  is set, then it must contain the destination address, otherwise
+	  it may contain the broadcast address or be NULL.
+	  (CONNECTED_DEST_HOST,CONNECTED_POINTOPOINT_HOST) Remove obsolete
+	  macros that were specific to IPv4 and not fully general.
+	  (CONNECTED_PEER) New macro to check ZEBRA_IFA_PEER flag.
+	  (CONNECTED_PREFIX) New macro giving the prefix to insert into
+	  the RIB: if CONNECTED_PEER, then use the destination (peer) address,
+	  else use the address field.
+	  (CONNECTED_ID) New macro to come up with an identifying address
+	  for the struct connected.
+	* if.c: (if_lookup_address, connected_lookup_address) Streamline
+	  logic with new CONNECTED_PREFIX macro.
+	* prefix.h: (PREFIX_COPY_IPV4, PREFIX_COPY_IPV6) New macros
+	  for better performance than the general prefix_copy function.
+	* zclient.c: (zebra_interface_address_read) For non-null destination
+	  addresses, set prefixlen to equal the address prefixlen.  This
+	  is needed to get the new CONNECTED_PREFIX macro to work properly.
+
 2006-10-14 Paul Jakma <paul.jakma@sun.com>
 
 	* if.c: (general) Handle upgrades from SUNWzebra, which tried
diff --git a/lib/if.c b/lib/if.c
index 4493cc74..db590f56 100644
--- a/lib/if.c
+++ b/lib/if.c
@@ -275,7 +275,6 @@ if_lookup_address (struct in_addr src)
   int bestlen = 0;
   struct listnode *cnode;
   struct interface *ifp;
-  struct prefix *p;
   struct connected *c;
   struct interface *match;
 
@@ -289,25 +288,12 @@ if_lookup_address (struct in_addr src)
     {
       for (ALL_LIST_ELEMENTS_RO (ifp->connected, cnode, c))
 	{
-	  if (c->address && (c->address->family == AF_INET))
+	  if (c->address && (c->address->family == AF_INET) &&
+	      prefix_match(CONNECTED_PREFIX(c), &addr) &&
+	      (c->address->prefixlen > bestlen))
 	    {
-	      if (CONNECTED_POINTOPOINT_HOST(c))
-		{
-		 /* PTP  links are conventionally identified 
-		    by the address of the far end - MAG */
-		  if (IPV4_ADDR_SAME (&c->destination->u.prefix4, &src))
-		    return ifp;
-		}
-	      else
-		{
-		  p = c->address;
-
-		  if (prefix_match (p, &addr) && p->prefixlen > bestlen)
-		    {
-		      bestlen = p->prefixlen;
-		      match = ifp;
-		    }
-		}
+	      bestlen = c->address->prefixlen;
+	      match = ifp;
 	    }
 	}
     }
@@ -728,7 +714,6 @@ connected_lookup_address (struct interface *ifp, struct in_addr dst)
 {
   struct prefix addr;
   struct listnode *cnode;
-  struct prefix *p;
   struct connected *c;
   struct connected *match;
 
@@ -740,24 +725,10 @@ connected_lookup_address (struct interface *ifp, struct in_addr dst)
 
   for (ALL_LIST_ELEMENTS_RO (ifp->connected, cnode, c))
     {
-      if (c->address && (c->address->family == AF_INET))
-        {
-	  if (CONNECTED_POINTOPOINT_HOST(c))
-	    {
-		     /* PTP  links are conventionally identified 
-			by the address of the far end - MAG */
-	      if (IPV4_ADDR_SAME (&c->destination->u.prefix4, &dst))
-		return c;
-	    }
-	  else
-	    {
-	      p = c->address;
-
-	      if (prefix_match (p, &addr) &&
-	      	  (!match || (p->prefixlen > match->address->prefixlen)))
-		match = c;
-	    }
-        }
+      if (c->address && (c->address->family == AF_INET) &&
+	  prefix_match(CONNECTED_PREFIX(c), &addr) &&
+	  (!match || (c->address->prefixlen > match->address->prefixlen)))
+	match = c;
     }
   return match;
 }
diff --git a/lib/if.h b/lib/if.h
index 0a4ff14d..985b4d68 100644
--- a/lib/if.h
+++ b/lib/if.h
@@ -154,26 +154,38 @@ struct connected
 
   /* Flags for connected address. */
   u_char flags;
-#define ZEBRA_IFA_SECONDARY   (1 << 0)
+#define ZEBRA_IFA_SECONDARY    (1 << 0)
+#define ZEBRA_IFA_PEER         (1 << 1)
+  /* N.B. the ZEBRA_IFA_PEER flag should be set if and only if
+     a peer address has been configured.  If this flag is set,
+     the destination field must contain the peer address.  
+     Otherwise, if this flag is not set, the destination address
+     will either contain a broadcast address or be NULL.
+   */
 
   /* Address of connected network. */
   struct prefix *address;
-  struct prefix *destination; /* broadcast or peer address; may be NULL */
+
+  /* Peer or Broadcast address, depending on whether ZEBRA_IFA_PEER is set.
+     Note: destination may be NULL if ZEBRA_IFA_PEER is not set. */
+  struct prefix *destination;
 
   /* Label for Linux 2.2.X and upper. */
   char *label;
 };
 
-/* Given an IPV4 struct connected, this macro determines whether a /32
-   peer address has been supplied (i.e. there is no subnet assigned) */
-#define CONNECTED_DEST_HOST(C) \
-	((C)->destination && ((C)->address->prefixlen == IPV4_MAX_PREFIXLEN))
+/* Does the destination field contain a peer address? */
+#define CONNECTED_PEER(C) CHECK_FLAG((C)->flags, ZEBRA_IFA_PEER)
+
+/* Prefix to insert into the RIB */
+#define CONNECTED_PREFIX(C) \
+	(CONNECTED_PEER(C) ? (C)->destination : (C)->address)
 
-/* Given an IPV4 struct connected, this macro determins whether it is
-   a point-to-point link with a /32 peer address (i.e. there
-   is no dedicated subnet for the PtP link) */
-#define CONNECTED_POINTOPOINT_HOST(C) \
-	(((C)->ifp->flags & IFF_POINTOPOINT) && CONNECTED_DEST_HOST(C))
+/* Identifying address.  We guess that if there's a peer address, but the
+   local address is in the same prefix, then the local address may be unique. */
+#define CONNECTED_ID(C)	\
+	((CONNECTED_PEER(C) && !prefix_match((C)->destination, (C)->address)) ?\
+	 (C)->destination : (C)->address)
 
 /* Interface hook sort. */
 #define IF_NEW_HOOK   0
diff --git a/lib/prefix.h b/lib/prefix.h
index 7afe7a1e..f2a2adfa 100644
--- a/lib/prefix.h
+++ b/lib/prefix.h
@@ -151,6 +151,9 @@ extern void prefix_ipv4_free (struct prefix_ipv4 *);
 extern int str2prefix_ipv4 (const char *, struct prefix_ipv4 *);
 extern void apply_mask_ipv4 (struct prefix_ipv4 *);
 
+#define PREFIX_COPY_IPV4(DST, SRC)	\
+	*((struct prefix_ipv4 *)(DST)) = *((const struct prefix_ipv4 *)(SRC));
+
 extern int prefix_ipv4_any (const struct prefix_ipv4 *);
 extern void apply_classful_mask_ipv4 (struct prefix_ipv4 *);
 
@@ -172,6 +175,9 @@ extern void prefix_ipv6_free (struct prefix_ipv6 *);
 extern int str2prefix_ipv6 (const char *, struct prefix_ipv6 *);
 extern void apply_mask_ipv6 (struct prefix_ipv6 *);
 
+#define PREFIX_COPY_IPV6(DST, SRC)	\
+	*((struct prefix_ipv6 *)(DST)) = *((const struct prefix_ipv6 *)(SRC));
+
 extern int ip6_masklen (struct in6_addr);
 extern void masklen2ip6 (int, struct in6_addr *);
 
diff --git a/lib/zclient.c b/lib/zclient.c
index a253af61..09a7d25e 100644
--- a/lib/zclient.c
+++ b/lib/zclient.c
@@ -780,7 +780,11 @@ zebra_interface_address_read (int type, struct stream *s)
        ifc = connected_add_by_prefix(ifp, &p,(memconstant(&d.u.prefix,0,plen) ?
 					      NULL : &d));
        if (ifc != NULL)
-       ifc->flags = ifc_flags;
+	 {
+	   ifc->flags = ifc_flags;
+	   if (ifc->destination)
+	     ifc->destination->prefixlen = ifc->address->prefixlen;
+	 }
     }
   else
     {