[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.

1 files changed, 21 insertions, 33 deletions

diff --git a/zebra/rt_netlink.c b/zebra/rt_netlink.c
index 216625e9..e2f1f9d9 100644
--- a/zebra/rt_netlink.c
+++ b/zebra/rt_netlink.c
@@ -577,8 +577,8 @@ netlink_interface_addr (struct sockaddr_nl *snl, struct nlmsghdr *h)
   struct ifaddrmsg *ifa;
   struct rtattr *tb[IFA_MAX + 1];
   struct interface *ifp;
-  void *addr = NULL;
-  void *broad = NULL;
+  void *addr;
+  void *broad;
   u_char flags = 0;
   char *label = NULL;
 
@@ -637,41 +637,29 @@ netlink_interface_addr (struct sockaddr_nl *snl, struct nlmsghdr *h)
         }
     }
   
+  /* logic copied from iproute2/ip/ipaddress.c:print_addrinfo() */
+  if (tb[IFA_LOCAL] == NULL)
+    tb[IFA_LOCAL] = tb[IFA_ADDRESS];
   if (tb[IFA_ADDRESS] == NULL)
     tb[IFA_ADDRESS] = tb[IFA_LOCAL];
   
-  if (ifp->flags & IFF_POINTOPOINT)
+  /* local interface address */
+  addr = (tb[IFA_LOCAL] ? RTA_DATA(tb[IFA_LOCAL]) : NULL);
+
+  /* is there a peer address? */
+  /* N.B. I do not understand why the memcmp compares 4 bytes regardless
+     of address family, but this is exactly how it appears in
+     print_addrinfo.  I wonder if it should be RTA_PAYLOAD(tb[IFA_ADDRESS])
+     instead of 4... */
+  if (tb[IFA_ADDRESS] &&
+      memcmp(RTA_DATA(tb[IFA_ADDRESS]), RTA_DATA(tb[IFA_LOCAL]), 4))
     {
-      if (tb[IFA_LOCAL])
-        {
-          addr = RTA_DATA (tb[IFA_LOCAL]);
-          if (tb[IFA_ADDRESS] &&
-	      memcmp(RTA_DATA(tb[IFA_ADDRESS]),RTA_DATA(tb[IFA_LOCAL]),4))
-	    /* if IFA_ADDRESS != IFA_LOCAL, then it's the peer address */
-            broad = RTA_DATA (tb[IFA_ADDRESS]);
-          else
-            broad = NULL;
-        }
-      else
-        {
-          if (tb[IFA_ADDRESS])
-            addr = RTA_DATA (tb[IFA_ADDRESS]);
-          else
-            addr = NULL;
-        }
+      broad = RTA_DATA(tb[IFA_ADDRESS]);
+      SET_FLAG (flags, ZEBRA_IFA_PEER);
     }
   else
-    {
-      if (tb[IFA_ADDRESS])
-        addr = RTA_DATA (tb[IFA_ADDRESS]);
-      else
-        addr = NULL;
-      
-      if (tb[IFA_BROADCAST])
-        broad = RTA_DATA(tb[IFA_BROADCAST]);
-      else
-        broad = NULL;
-    }
+    /* seeking a broadcast address */
+    broad = (tb[IFA_BROADCAST] ? RTA_DATA(tb[IFA_BROADCAST]) : NULL);
 
   /* addr is primary key, SOL if we don't have one */
   if (addr == NULL)
@@ -707,7 +695,7 @@ netlink_interface_addr (struct sockaddr_nl *snl, struct nlmsghdr *h)
   if (ifa->ifa_family == AF_INET6)
     {
       if (h->nlmsg_type == RTM_NEWADDR)
-        connected_add_ipv6 (ifp,
+        connected_add_ipv6 (ifp, flags,
                             (struct in6_addr *) addr, ifa->ifa_prefixlen,
                             (struct in6_addr *) broad, label);
       else
@@ -1849,7 +1837,7 @@ netlink_address (int cmd, int family, struct interface *ifp,
 
   if (family == AF_INET && cmd == RTM_NEWADDR)
     {
-      if (if_is_broadcast (ifp) && ifc->destination)
+      if (!CONNECTED_PEER(ifc) && ifc->destination)
         {
           p = ifc->destination;
           addattr_l (&req.n, sizeof req, IFA_BROADCAST, &p->u.prefix,