route.h 7.38 KB
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/*
 *	BIRD Internet Routing Daemon -- Routing Table
 *
 *	(c) 1998 Martin Mares <mj@ucw.cz>
 *
 *	Can be freely distributed and used under the terms of the GNU GPL.
 */

#ifndef _BIRD_ROUTE_H_
#define _BIRD_ROUTE_H_

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#include "lib/resource.h"
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/*
 *	Generic data structure for storing network prefixes. Also used
 *	for the master routing table. Currently implemented as a radix
 *	trie.
 *
 *	Available operations:
 *		- insertion of new entry
 *		- deletion of entry
 *		- searching of entry by network prefix
 *		- searching of entry by IP address (longest match)
 */

struct fib_node {
  ip_addr prefix;			/* In host order */
  byte pxlen;
  byte flags;				/* ??? define them ??? */
  byte pad0, pad1;			/* ??? use ??? */
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  struct fib_node *next;		/* Next in hash chain */
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};

struct fib {
  slab fib_slab;			/* Slab holding all fib nodes */
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  struct fib_node *hash_table;		/* Node hash table */
  unsigned int hash_size;		/* Number of hash table entries (a power of two) */
  unsigned int entries;			/* Number of entries */
  unsigned int entries_min, entries_max;/* Entry count limits (else start rehashing) */
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  void (*init)(struct fib_node *);	/* Constructor */
};

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void fib_init(struct fib *, pool *, unsigned node_size, unsigned hash_size, void (*init)(struct fib_node *));
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void *fib_find(struct fib *, ip_addr *, int);	/* Find or return NULL if doesn't exist */
void *fib_get(struct fib *, ip_addr *, int); 	/* Find or create new if nonexistent */
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void fib_delete(void *);		/* Remove fib entry */
void fib_free(struct fib *);		/* Destroy the fib */

#define FIB_WALK(fib, op) {					\
	struct fib_node *f, **ff = (fib)->hash_table;		\
	unsigned int count = (fib)->hash_size;			\
	while (count--)						\
	  for(f = *ff++; f; f=f->next)				\
	    {							\
	      op						\
	    }							\
	}

/*
 *	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.
 */

typedef struct neighbor {
  ip_addr addr;				/* Address of the neighbor */
  struct next *next;			/* Next in hashed chain */
  struct next *sibling;			/* Next in per-device chain */
  struct proto *proto;			/* Protocol this belongs to */
  void *data;				/* Protocol-specific data */
} neighbor;

neighbor *neigh_find(ip_addr *);	/* NULL if not a neighbor */
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/*
 *	Master Routing Table. Generally speaking, it's a FIB with each entry
 *	pointing to a list of route entries representing routes to given network.
 *	Each of the RTE's contains variable data (the preference and protocol-dependent
 *	metrics) and a pointer to route attribute block common for many routes).
 */

typedef struct network {
  struct fib_node n;
  struct rte *routes;			/* Available routes for this network */
  struct network *next;			/* Next in Recalc Chain */
} net;

typedef struct rte {
  struct rte *next;
  struct rtattr *attrs;
  byte flags;				/* Flags (REF_...) */
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  byte pflags;				/* Protocol-specific flags */
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  word pref;				/* Route preference */
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  u32 lastmod;				/* Last modified (time) */
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  union {				/* Protocol-dependent data (metrics etc.) */
#ifdef CONFIG_STATIC
    struct {
    } stat;
#endif
#ifdef CONFIG_RIP
    struct {
      byte metric;			/* RIP metric */
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      u16 tag;				/* External route tag */
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    } rip;
#endif
#ifdef CONFIG_OSPF
    struct {
      u32 metric1, metric2;		/* OSPF Type 1 and Type 2 metrics */
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      u32 tag;				/* External route tag */
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    } ospf;
#endif
#ifdef CONFIG_BGP
    struct {
    } bgp;
#endif
  } u;
} rte;

#define REF_CHOSEN 1			/* Currently chosen route */

typedef struct rte rte;

/*
 *	Route Attributes
 *
 *	Beware: All standard BGP attributes must be represented here instead
 *	of making them local to the route. This is needed to ensure proper
 *	construction of BGP route attribute lists.
 */

struct rtattr {
  struct rtattr *next, *prev;		/* Hash chain */
  struct rtattr *garbage;		/* Garbage collector chain */
  struct proto *proto;			/* Protocol instance */
  unsigned uc;				/* Use count */
  byte source;				/* Route source (RTS_...) */
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  byte scope;				/* Route scope (SCOPE_... -- see ip.h) */
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  byte cast;				/* Casting type (RTC_...) */
  byte dest;				/* Route destination type (RTD_...) */
  byte tos;				/* TOS of this route */
  byte flags;				/* Route flags (RTF_...) */
  ip_addr gw;				/* Next hop */
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  ip_addr from;				/* Advertising router */
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  struct iface *iface;			/* Outgoing interface */
  struct ea_list *attrs;		/* Extended Attribute chain */
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  union {				/* Protocol-specific data */
  } u;
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} rta;

#define RTS_STATIC 1			/* Normal static route */
#define RTS_INHERIT 2			/* Route inherited from kernel */
#define RTS_DEVICE 3			/* Device route */
#define RTS_STATIC_DEVICE 4		/* Static device route */
#define RTS_REDIRECT 5			/* Learned via redirect */
#define RTS_RIP 6			/* RIP route */
#define RTS_RIP_EXT 7			/* RIP external route */
#define RTS_OSPF 8			/* OSPF route */
#define RTS_OSPF_EXT 9			/* OSPF external route */
#define RTS_OSPF_IA 10			/* OSPF inter-area route */
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#define RTS_OSPF_BOUNDARY 11		/* OSPF route to boundary router (???) */
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#define RTS_BGP 12			/* BGP route */

#define RTC_UNICAST 0
#define RTC_BROADCAST 1
#define RTC_MULTICAST 2
#define RTC_ANYCAST 3			/* IPv6 Anycast */

#define RTD_ROUTER 0			/* Next hop is neighbor router */
#define RTD_DEVICE 1			/* Points to device */
#define RTD_BLACKHOLE 2			/* Silently drop packets */
#define RTD_UNREACHABLE 3		/* Reject as unreachable */
#define RTD_PROHIBIT 4			/* Administratively prohibited */

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#define RTF_EXTERIOR 1			/* Learned via exterior protocol */
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#define RTF_TAGGED 2			/* Tagged external route learned via IGP */
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/*
 *	Extended Route Attributes
 */

typedef struct eattr {
  byte protocol;			/* Protocol ID (EAP_...) */
  byte flags;				/* Attribute flags (EAF_...) */
  byte id;				/* Protocol-dependent ID */
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  byte rfu;				/* ??? */
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  union {
    u32 data;
    struct adata *ptr;			/* Attribute data elsewhere */
  } u;
} eattr;

#define EAP_GENERIC 0			/* Generic attributes */
#define EAP_BGP 1			/* BGP attributes */

#define EAF_OPTIONAL 0x80		/* Refer to BGP specs for full meaning */
#define EAF_TRANSITIVE 0x40
#define EAF_PARTIAL 0x20
#define EAF_EXTENDED_LENGTH 0x10	/* Not used by us, internal to BGP */
#define EAF_LONGWORD 0x01		/* Embedded value [Not a BGP flag!] */

struct adata {
  unsigned int length;
  byte data[0];
};

typedef struct ea_list {
  struct ea_list *next;			/* In case we have an override list */
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  byte sorted;				/* `Really sorted' flag (???) */
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  byte rfu;
  word nattrs;				/* Number of attributes */
  eattr attrs[0];			/* Attribute definitions themselves */
} ea_list;

eattr *ea_find(ea_list *, unsigned protocol, unsigned id);

#define EA_LIST_NEW(p, alloc, n) do {				\
	unsigned cnt = n;				       	\
	p = alloc(sizeof(ea_list) + cnt*sizeof(eattr));		\
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	memset(p, 0, sizeof(ea_list));				\
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	p->nattrs = cnt;					\
} while(0)

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/*
 *	Default protocol preferences
 */

#define DEF_PREF_DIRECT	    	240	/* Directly connected */
#define DEF_PREF_STATIC		200	/* Static route */
#define DEF_PREF_OSPF_INTERNAL	150	/* OSPF intra-area, inter-area and type 1 external routes */
#define DEF_PREF_RIP		120	/* RIP */
#define DEF_PREF_BGP		100	/* BGP */
#define DEF_PREF_OSPF_EXTERNAL	80	/* OSPF external routes */
#define DEF_PREF_RIP_EXTERNAL	70	/* RIP external routes */
#define DEF_PREF_SINK		10	/* Sink route */

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#endif