From 4cc78c5082344f0d237a5cdfb05e53dfd04ffd8b Mon Sep 17 00:00:00 2001
From: Martin Mares <mj@ucw.cz>
Date: Mon, 1 Jun 1998 21:41:11 +0000
Subject: - Rewrote whole interface logic. Removed support for multiple
 addresses per   interface since it makes much trouble everywhere. Instead, we
 understand   secondary addresses as subinterfaces.

- In case interface addresses or basic flags change, we simply convert it
  to a down/up sequence.

- Implemented the universal neighbour cache. (Just forget what did previous
  includes say of neighbour caching, this one is brand new.)
---
 nest/iface.h | 57 ++++++++++++++++++++++++++++++++++++++++++---------------
 1 file changed, 42 insertions(+), 15 deletions(-)

(limited to 'nest/iface.h')

diff --git a/nest/iface.h b/nest/iface.h
index 4df9873..c359449 100644
--- a/nest/iface.h
+++ b/nest/iface.h
@@ -18,8 +18,13 @@ struct iface {
   char name[16];
   unsigned flags;
   unsigned mtu;
-  struct ifa *ifa;			/* First address is primary */
   unsigned index;			/* OS-dependent interface index */
+  ip_addr ip;				/* IP address of this host */
+  ip_addr prefix;			/* Network prefix */
+  unsigned pxlen;			/* Prefix length */
+  ip_addr brd;				/* Broadcast address */
+  ip_addr opposite;			/* Opposite end of a point-to-point link */
+  struct neighbor *neigh;		/* List of neighbors on this interface */
 };
 
 #define IF_UP 1
@@ -33,25 +38,12 @@ struct iface {
 #define IF_IGNORE 256
 #define IF_UPDATED 0x1000		/* Touched in last scan */
 
-/* Interface address */
-
-struct ifa {
-  struct ifa *next;
-  ip_addr ip;				/* IP address of this host */
-  ip_addr prefix;			/* Network prefix */
-  unsigned pxlen;			/* Prefix length */
-  ip_addr brd;				/* Broadcast address */
-  ip_addr opposite;			/* Opposite end of a point-to-point link */
-  struct neighbor *neigh;		/* List of neighbors on this interface */
-};
-
 /* Interface change events */
 
 #define IF_CHANGE_UP 1
 #define IF_CHANGE_DOWN 2
-#define IF_CHANGE_FLAGS 4
+#define IF_CHANGE_FLAGS 4		/* Can be converted to down/up internally */
 #define IF_CHANGE_MTU 8
-#define IF_CHANGE_ADDR 16
 
 void if_init(void);
 void if_dump(struct iface *);
@@ -59,4 +51,39 @@ void if_dump_all(void);
 void if_update(struct iface *);
 void if_end_update(void);
 
+/*
+ *	Neighbor Cache. We hold (direct neighbor, protocol) pairs we've seen
+ *	along with pointer to protocol-specific data.
+ *
+ *	The primary goal of this cache is to quickly validate all incoming
+ *	packets if their have been sent by our neighbors and to notify
+ *	protocols about lost neighbors when an interface goes down.
+ *
+ *	Anyway, it can also contain `sticky' entries for currently unreachable
+ *	addresses which cause notification when the address becomes a neighbor.
+ */
+
+typedef struct neighbor {
+  node n;				/* Node in global neighbor list */
+  ip_addr addr;				/* Address of the neighbor */
+  struct iface *iface;			/* Interface address it's connected to */
+  struct neighbor *sibling;		/* Next in per-device chain */
+  struct proto *proto;			/* Protocol this belongs to */
+  void *data;				/* Protocol-specific data */
+  unsigned flags;
+} neighbor;
+
+#define NEF_STICKY 1
+
+/*
+ * Find neighbor or return NULL if it doesn't exist.
+ * If you specify flags == NEF_STICKY, a sticky entry is created if the
+ * address is not a neighbor, but NULL can still be returned if the address
+ * given is invalid.
+ */
+neighbor *neigh_find(struct proto *, ip_addr *, unsigned flags);
+
+void neigh_dump(neighbor *);
+void neigh_dump_all(void);
+
 #endif
-- 
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