First look at data structures. More to come tomorrow...

25 files changed, 897 insertions, 0 deletions

diff --git a/Makefile b/Makefile
new file mode 100644
index 0000000..0c62fe5
--- /dev/null
+++ b/Makefile
@@ -0,0 +1,23 @@
+# Makefile for the BIRD Internet Routing Daemon
+# (c) 1998 Martin Mares <mj@ucw.cz>
+
+TOPDIR=$(shell pwd)
+CFLAGS=-O2 -Wall -W -Wstrict-prototypes -Wno-unused -Wno-parentheses -I$(TOPDIR)
+
+PROTOCOLS=
+DIRS=sysdep/linux nest $(protocols) lib
+ARCHS=$(join $(addsuffix /,$(DIRS)),$(subst /,_,$(addsuffix .a,$(DIRS))))
+
+export
+
+all: all-dirs bird
+
+all-dirs:
+	set -e ; for a in $(DIRS) ; do $(MAKE) -C $$a ; done
+
+bird: $(ARCHS)
+	$(CC) $(LDFLAGS) -o $@ $^
+
+clean:
+	rm -f `find . -name "*~" -or -name "*.[oa]" -or -name "\#*\#" -or -name TAGS -or -name core`
+	rm -f bird
diff --git a/Rules b/Rules
new file mode 100644
index 0000000..f6baacd
--- /dev/null
+++ b/Rules
@@ -0,0 +1,12 @@
+# Makefile for the BIRD Internet Routing Daemon
+# (c) 1998 Martin Mares <mj@ucw.cz>
+
+THISDIR=$(shell pwd)
+RELDIR=$(subst $(TOPDIR)/,,$(THISDIR))
+ANAME=$(subst /,_,$(RELDIR)).a
+
+all: $(ANAME)
+
+$(ANAME): $(OBJS)
+	rm -f $(ANAME)
+	ar rcs $(ANAME) $(OBJS)
diff --git a/TODO b/TODO
new file mode 100644
index 0000000..10aeef9
--- /dev/null
+++ b/TODO
@@ -0,0 +1,143 @@
+Core
+~~~~
+- route validation
+- fake multipath?
+- config file: symbolic constants?
+- counters (according to SNMP MIB?)
+- generation of subnet mask ICMP's for v6?
+- debugging dumps and protocol tracing!
+- unaligned accesses?
+
+
+RIP
+~~~
+- RIP: export-only and import-only mode?
+- drop RIPv1 (Historic protocol)?
+
+OSPF
+~~~~
+
+Almquist & Kastenholz                                         [Page 111]
+RFC 1716          Towards Requirements for IP Routers      November 1994
+
+
+7.2.2.2  Specific Issues
+
+         Virtual Links
+
+              There is a minor error in the specification that can cause
+              routing loops when all of the following conditions are
+              simultaneously true:
+
+              (1)  A virtual link is configured through a transit area,
+
+              (2)  Two separate paths exist, each having the same
+                   endpoints, but one utilizing only non-virtual
+                   backbone links, and the other using links in the
+                   transit area, and
+
+              (3)  The latter path is part of the (underlying physical
+                   representation of the) configured virtual link,
+                   routing loops may occur.
+
+              To prevent this, an implementation of OSPF SHOULD invoke
+              the calculation in Section 16.3 of [ROUTE:1] whenever any
+              part of the path to the destination is a virtual link (the
+              specification only says this is necessary when the first
+              hop is a virtual link).
+
+BGP
+~~~
+- BGP:
+	- in, local, out RIB
+	- maxsize=4096
+	- BGP identifier aka router id
+	- removal of loops
+	- aggregation, ATOMIC_AGGREGATE
+	- communities
+	- confederations
+	- attributes must be sorted!
+	- re-export of NEXT_HOP attribute
+	- BGP session over currently down interface
+	- route flap dampening?
+	- LOCAL_PREF attribute
+	- error notification received -> log error
+	- set TTL to 1 (configurable?)
+	- consulting IGP for next-hop information? (what if it changes?)
+	- inter-advertisement delay???!
+	- normalize (sort) incoming AS-SET's
+	- maximum length of AS paths
+
+	- expected neighbor AS
+	- hold time
+	- idle timer after error: initial value, exponential growth, maximum value
+
+- address testing macros (ALL_ZEROS)
+- all internal tables are in network order (?)
+- logging of errors and debug dumps
+- filter: logging of dropped routes (?)
+- limitation of memory consumption: per-process and total
+- alloca
+- precedence of all packets (incl. TCP)
+- adding of route: clear all bits not covered by masklen
+- switch: generate default route only if at least one BGP connection exists
+
+- route update: new, change, remove
+- route recalculation timing
+
+- CONFIG_TOS
+- CONFIG_MULTIPATH
+
+- reconfiguration without restart of all protocols?
+- change of interface address: ??? (down and up?)
+- "generate default route" switch for all IGP's
+
+- RIPv2:
+	- Route Tag
+	- limit routing table xfer (frequency, only to neighbors)
+	- multicast on/off
+	- remember routes for all neighbors?
+
+- BGP:
+	- import of IGP routes (use external route tags from OSPF)
+
+- Interface:
+	- RIP metric
+	- multicast capability flag
+	- MTU
+	- OSPF metrics (per-TOS)
+
+- running protocol on an interface:
+	- interface is not required to exist
+	- can specify a wildcard pattern or an interface list
+
+- preferences:
+	- directly connected
+	- static
+	- OSPF internal, OSPF ext type 1 (comparable metrics), OSPF inter-area
+	- RIP
+	- BGP
+	- OSPF ext type 2
+	- sink
+
+- lib:
+	- MD5
+
+- OSPF:
+	- Dijkstra: use Fibonacci heaps?
+	- point-to-point interface with address: advertise as stub network
+	- static routes: stub networks?
+	- modes: PtP, PtP-unnumbered, Broadcast, NBMA, point-to-multipoint
+	- importing of device routes for networks where we don't run OSPF
+	- tie breaking for equal type 2 ext metrics by using internal (type 1) metric
+	- SPF tree recalc timing (per-area timers?)
+	- aggregation: specify network list for each area
+	- stub area: either no external routes or only default route
+	- automatic generation of external route tags (RFC1403) -- what about
+	  using the same rule for RIPv2? [shared code?]
+
+- timers - one-shot and periodic, resolution 1 sec, randomized
+- re-configuration: restart of routing protocols (shutdown mode)
+- route: originating AS
+
+- Check incoming packets and log errors!!
diff --git a/lib/Makefile b/lib/Makefile
new file mode 100644
index 0000000..214f76a
--- /dev/null
+++ b/lib/Makefile
@@ -0,0 +1,3 @@
+OBJS=lists.o
+
+include $(TOPDIR)/Rules
diff --git a/lib/birdlib.h b/lib/birdlib.h
new file mode 100644
index 0000000..fb4814f
--- /dev/null
+++ b/lib/birdlib.h
@@ -0,0 +1,17 @@
+/*
+ *	BIRD Library
+ *
+ *	(c) 1998 Martin Mares <mj@ucw.cz>
+ *
+ *	Can be freely distributed and used under the terms of the GNU GPL.
+ */
+
+#ifndef _BIRD_BIRDLIB_H_
+#define _BIRD_BIRDLIB_H_
+
+/* Ugly structure offset handling macros */
+
+#define OFFSETOF(s, i) ((unsigned int)&((s *)0)->i)
+#define SKIP_BACK(s, i, p) ((s *)((char *)p - OFFSETOF(s, i)))
+
+#endif
diff --git a/lib/lists.c b/lib/lists.c
new file mode 100644
index 0000000..321a5f0
--- /dev/null
+++ b/lib/lists.c
@@ -0,0 +1,76 @@
+/*
+ *	BIRD Library -- Linked Lists
+ *
+ *	(c) 1998 Martin Mares <mj@ucw.cz>
+ *
+ *	Can be freely distributed and used under the terms of the GNU GPL.
+ */
+
+#define _BIRD_LISTS_C_
+
+#include <nest/bird.h>
+#include <lib/lists.h>
+
+LIST_INLINE void
+add_tail(list *l, node *n)
+{
+  node *z = l->tail;
+
+  n->next = (node *) &l->tail;
+  n->prev = z;
+  z->next = n;
+  l->tail = n;
+}
+
+LIST_INLINE void
+add_head(list *l, node *n)
+{
+  node *z = l->head;
+
+  n->next = z;
+  n->prev = (node *) &l->head;
+  z->prev = n;
+  l->head = n;
+}
+
+LIST_INLINE void
+insert_node(node *n, node *after)
+{
+  node *z = after->next;
+
+  n->next = z;
+  n->prev = after;
+  after->next = n;
+  z->prev = n;
+}
+
+LIST_INLINE void
+rem_node(node *n)
+{
+  node *z = n->prev;
+  node *x = n->next;
+
+  z->next = x;
+  x->prev = z;
+}
+
+LIST_INLINE void
+init_list(list *l)
+{
+  l->head = (node *) &l->null;
+  l->null = NULL;
+  l->tail = (node *) &l->head;
+}
+
+LIST_INLINE void
+add_tail_list(list *to, list *l)
+{
+  node *p = to->tail;
+  node *q = l->head;
+
+  p->next = q;
+  q->prev = p;
+  q = l->tail;
+  q->next = (node *) &to->null;
+  to->tail = q;
+}
diff --git a/lib/lists.h b/lib/lists.h
new file mode 100644
index 0000000..acc054d
--- /dev/null
+++ b/lib/lists.h
@@ -0,0 +1,42 @@
+/*
+ *	BIRD Library -- Linked Lists
+ *
+ *	(c) 1998 Martin Mares <mj@ucw.cz>
+ *
+ *	Can be freely distributed and used under the terms of the GNU GPL.
+ */
+
+#ifndef _BIRD_LISTS_H_
+#define _BIRD_LISTS_H_
+
+typedef struct node {
+  struct node *next, *prev;
+} node;
+
+typedef struct list {			/* In fact two overlayed nodes */
+  struct node *head, *null, *tail;
+} list;
+
+#define NODE (node *)
+#define HEAD(list) ((void *)((list).head))
+#define TAIL(list) ((void *)((list).tail))
+#define WALK_LIST(n,list) for((n)=HEAD(list);(NODE (n))->next; \
+				n=(void *)((NODE (n))->next))
+#define EMPTY_LIST(list) (!(list).head->next)
+
+void add_tail(list *, node *);
+void add_head(list *, node *);
+void rem_node(node *);
+void add_tail_list(list *, list *);
+void init_list(list *);
+void insert_node(node *, node *);
+
+#ifndef _BIRD_LISTS_C_
+#define LIST_INLINE extern inline
+#include <lib/lists.c>
+#undef LIST_INLINE
+#else
+#define LIST_INLINE
+#endif
+
+#endif
diff --git a/lib/resource.h b/lib/resource.h
new file mode 100644
index 0000000..a1d229e
--- /dev/null
+++ b/lib/resource.h
@@ -0,0 +1,70 @@
+/*
+ *	BIRD Resource Manager
+ *
+ *	(c) 1998 Martin Mares <mj@ucw.cz>
+ *
+ *	Can be freely distributed and used under the terms of the GNU GPL.
+ */
+
+#ifndef _BIRD_RESOURCE_H_
+#define _BIRD_RESOURCE_H_
+
+#include <lib/lists.h>
+
+/* Resource */
+
+typedef struct resource {
+	node n;				/* Inside resource pool */
+	struct resclass *class;		/* Resource class */
+} resource;
+
+/* Resource class */
+
+struct resclass {
+	char *name;			/* Resource class name */
+	unsigned size;			/* Standard size of single resource */
+	void (*free)(resource *);	/* Freeing function */
+	void (*dump)(resource *);	/* Dump to debug output */
+};
+
+/* Generic resource manipulation */
+
+typedef struct pool pool;
+
+pool *rp_new(pool *);			/* Create new pool */
+void rp_init(pool *);			/* Initialize static pool */
+void rp_empty(pool *);			/* Free everything in the pool */
+void rfree(void *);			/* Free single resource */
+void rdump(void *);			/* Dump to debug output */
+
+void ralloc(pool *, struct resclass *);
+
+/* Normal memory blocks */
+
+void *mb_alloc(pool *, unsigned size);
+void *mb_free(void *);
+
+/* Memory pools with linear allocation */
+
+typedef struct mempool mempool;
+
+mempool *mp_new(pool *, unsigned blk);
+void mp_trim(pool *);				/* Free unused memory */
+void *mp_alloc(mempool *, unsigned size);	/* Aligned */
+void *mp_allocu(mempool *, unsigned size);	/* Unaligned */
+void *mp_allocz(mempool *, unsigned size);	/* With clear */
+
+/* Slabs */
+
+typedef struct slab slab;
+
+slab *sl_new(pool *, unsigned size);
+void *sl_alloc(slab *);
+void sl_free(slab *, void *);
+
+/* Low-level memory allocation functions, please don't use */
+
+void *xmalloc(unsigned);
+#define xfree(x) free(x)
+
+#endif
diff --git a/lib/socket.h b/lib/socket.h
new file mode 100644
index 0000000..4f68a16
--- /dev/null
+++ b/lib/socket.h
@@ -0,0 +1,16 @@
+/*
+ *	BIRD Socket Interface
+ *
+ *	(c) 1998 Martin Mares <mj@ucw.cz>
+ *
+ *	Can be freely distributed and used under the terms of the GNU GPL.
+ */
+
+#ifndef _BIRD_SOCKET_H_
+#define _BIRD_SOCKET_H_
+
+#include <lib/resource.h>
+
+typedef struct birdsock socket;
+
+#endif
diff --git a/lib/timer.h b/lib/timer.h
new file mode 100644
index 0000000..29f20c4
--- /dev/null
+++ b/lib/timer.h
@@ -0,0 +1,26 @@
+/*
+ *	BIRD Timers
+ *
+ *	(c) 1998 Martin Mares <mj@ucw.cz>
+ *
+ *	Can be freely distributed and used under the terms of the GNU GPL.
+ */
+
+#ifndef _BIRD_TIMER_H_
+#define _BIRD_TIMER_H_
+
+#include <lib/resource.h>
+
+typedef struct timer {
+	resource r;
+	void (*hook)(struct timer *);
+	void *data;
+	/* internal fields should be here */
+} timer;
+
+timer *tm_new(pool *, void (*hook)(timer *), void *data);
+void tm_start(timer *, unsigned after);
+void tm_stop(timer *);
+void tm_trigger(timer *);
+
+#endif
diff --git a/lib/unaligned.h b/lib/unaligned.h
new file mode 100644
index 0000000..29fcee9
--- /dev/null
+++ b/lib/unaligned.h
@@ -0,0 +1,12 @@
+/*
+ *	Unaligned Data Accesses
+ *
+ *	(c) 1998 Martin Mares <mj@ucw.cz>
+ *
+ *	Can be freely distributed and used under the terms of the GNU GPL.
+ */
+
+#ifndef _BIRD_UNALIGNED_H_
+#define _BIRD_UNALIGNED_H_
+
+#endif
diff --git a/nest/Makefile b/nest/Makefile
new file mode 100644
index 0000000..d6c0e6e
--- /dev/null
+++ b/nest/Makefile
@@ -0,0 +1,3 @@
+OBJS=main.o
+
+include $(TOPDIR)/Rules
diff --git a/nest/bird.h b/nest/bird.h
new file mode 100644
index 0000000..e8c3318
--- /dev/null
+++ b/nest/bird.h
@@ -0,0 +1,24 @@
+/*
+ *	BIRD Internet Routing Daemon -- Basic Declarations
+ *
+ *	(c) 1998 Martin Mares <mj@ucw.cz>
+ *
+ *	Can be freely distributed and used under the terms of the GNU GPL.
+ */
+
+#ifndef _BIRD_BIRD_H_
+#define _BIRD_BIRD_H_
+
+#include <sysdep/config.h>
+#include <lib/birdlib.h>
+
+#ifndef IPV6
+#include <nest/ipv4.h>
+#else
+#include <nest/ipv6.h>
+#endif
+
+extern u32 router_id;			/* Our Router ID */
+extern u16 this_as;			/* Our Autonomous System Number */
+
+#endif
diff --git a/nest/confile.h b/nest/confile.h
new file mode 100644
index 0000000..1089e76
--- /dev/null
+++ b/nest/confile.h
@@ -0,0 +1,12 @@
+/*
+ *	BIRD Internet Routing Daemon -- Configuration File
+ *
+ *	(c) 1998 Martin Mares <mj@ucw.cz>
+ *
+ *	Can be freely distributed and used under the terms of the GNU GPL.
+ */
+
+#ifndef _BIRD_CONFILE_H_
+#define _BIRD_CONFILE_H_
+
+#endif
diff --git a/nest/iface.h b/nest/iface.h
new file mode 100644
index 0000000..2d0d757
--- /dev/null
+++ b/nest/iface.h
@@ -0,0 +1,12 @@
+/*
+ *	BIRD Internet Routing Daemon -- Network Interfaces
+ *
+ *	(c) 1998 Martin Mares <mj@ucw.cz>
+ *
+ *	Can be freely distributed and used under the terms of the GNU GPL.
+ */
+
+#ifndef _BIRD_IFACE_H_
+#define _BIRD_IFACE_H_
+
+#endif
diff --git a/nest/ipv4.h b/nest/ipv4.h
new file mode 100644
index 0000000..7524229
--- /dev/null
+++ b/nest/ipv4.h
@@ -0,0 +1,20 @@
+/*
+ *	BIRD -- IP Addresses et Cetera for IPv4
+ *
+ *	(c) 1998 Martin Mares <mj@ucw.cz>
+ *
+ *	Can be freely distributed and used under the terms of the GNU GPL.
+ */
+
+#ifndef _BIRD_IPV4_H_
+#define _BIRD_IPV4_H_
+
+#include <netinet/in.h>
+
+typedef struct ipv4_addr {
+  u32 addr;
+} ip_addr;
+
+#define ipa_equal(x,y) ((x).addr == (y).addr)
+
+#endif
diff --git a/nest/ipv6.h b/nest/ipv6.h
new file mode 100644
index 0000000..5d5e354
--- /dev/null
+++ b/nest/ipv6.h
@@ -0,0 +1,21 @@
+/*
+ *	BIRD -- IP Addresses et Cetera for IPv6
+ *
+ *	(c) 1998 Martin Mares <mj@ucw.cz>
+ *
+ *	Can be freely distributed and used under the terms of the GNU GPL.
+ */
+
+#ifndef _BIRD_IPV4_H_
+#define _BIRD_IPV4_H_
+
+#include <netinet/in.h>
+#include <string.h>
+
+typedef struct ipv4_addr {
+  u32 addr[4];
+} ip_addr;
+
+#define ipa_equal(x,y) (!memcmp(&(x),&(y),sizeof(ip_addr)))
+
+#endif
diff --git a/nest/main.c b/nest/main.c
new file mode 100644
index 0000000..8f60f27
--- /dev/null
+++ b/nest/main.c
@@ -0,0 +1,23 @@
+/*
+ *	BIRD Internet Routing Daemon
+ *
+ *	(c) 1998 Martin Mares <mj@ucw.cz>
+ *
+ *	Can be freely distributed and used under the terms of the GNU GPL.
+ */
+
+#include <nest/bird.h>
+#include <lib/lists.h>
+
+#include <nest/resource.h>
+
+int
+main(void)
+{
+	ip_addr x,y;
+
+	x=y;
+	if (ipa_equal(x,y)) return 1;
+
+	return 0;
+}
diff --git a/nest/protocol.h b/nest/protocol.h
new file mode 100644
index 0000000..adca114
--- /dev/null
+++ b/nest/protocol.h
@@ -0,0 +1,66 @@
+/*
+ *	BIRD Internet Routing Daemon -- Protocols
+ *
+ *	(c) 1998 Martin Mares <mj@ucw.cz>
+ *
+ *	Can be freely distributed and used under the terms of the GNU GPL.
+ */
+
+#ifndef _BIRD_PROTOCOL_H_
+#define _BIRD_PROTOCOL_H_
+
+#include <lib/resource.h>
+
+/*
+ *	Routing Protocol
+ */
+
+struct protocol {
+  char *name;
+  unsigned type;			/* ??? List values ??? */
+  unsigned debug;			/* Default debugging flags */
+
+  void (*init)(struct protocol *);	/* Boot time */
+  void (*preconfig)(struct protocol *);	/* Just before configuring */
+  void (*postconfig)(struct protocol *); /* After configuring */
+};
+
+void protos_init(void);
+void protos_preconfig(void);
+void protos_postconfig(void);
+
+/*
+ *	Known protocols
+ */
+
+extern struct protocol proto_static;
+
+/*
+ *	Routing Protocol Instance
+ */
+
+struct proto {
+  struct proto *next;
+  struct protocol *proto;		/* Protocol */
+  char *name;				/* Name of this instance */
+  unsigned debug;			/* Debugging flags */
+  pool *pool;				/* Local objects */
+  unsigned preference;			/* Default route preference */
+
+  void (*if_notify)(struct proto *, struct iface *old, struct iface *new);
+  void (*rt_notify)(struct proto *, struct rte *old, struct rte *new);
+  void (*debug)(struct proto *);		/* Debugging dump */
+  void (*start)(struct proto *);		/* Start the instance */
+  void (*shutdown)(struct proto *, int time);	/* Stop the instance */
+
+  /* Reconfigure function? */
+  /* Interface patterns */
+  /* Input/output filters */
+  /* Connection to routing tables? */
+
+  /* Hic sunt protocol-specific data */
+};
+
+void *proto_new(struct protocol *, unsigned size);
+
+#endif
diff --git a/nest/route.h b/nest/route.h
new file mode 100644
index 0000000..e968e12
--- /dev/null
+++ b/nest/route.h
@@ -0,0 +1,190 @@
+/*
+ *	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_
+
+#include <lib/resource.h>
+
+/*
+ *	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 ??? */
+  struct fib_node *left, *right, *up;	/* Radix Trie links */
+};
+
+struct fib {
+  slab fib_slab;			/* Slab holding all fib nodes */
+  struct fib_node root;
+  void (*init)(struct fib_node *);	/* Constructor */
+};
+
+void fib_init(struct fib *, pool *, unsigned node_size, void (*init)(struct fib_node *));
+void *fib_find(struct fib *, ip_addr *, int);	/* Find or return NULL if doesn't exist */
+void *fib_find_ip(struct fib *, ip_addr *); 	/* Longest match (always exists) */
+void *fib_get(struct fib *, ip_addr *, int); 	/* Find or create new if nonexistent */
+void fib_delete(struct fib *);
+
+/*
+ *	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_...) */
+  byte rfu;
+  word pref;				/* Route preference */
+  union {				/* Protocol-dependent data (metrics etc.) */
+#ifdef CONFIG_STATIC
+    struct {
+    } stat;
+#endif
+#ifdef CONFIG_RIP
+    struct {
+      byte metric;			/* RIP metric */
+    } rip;
+#endif
+#ifdef CONFIG_OSPF
+    struct {
+      u32 metric1, metric2;		/* OSPF Type 1 and Type 2 metrics */
+    } 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_...) */
+  byte scope;				/* Route scope (SCOPE_...) */
+  byte cast;				/* Casting type (RTC_...) */
+  byte dest;				/* Route destination type (RTD_...) */
+  byte tos;				/* TOS of this route */
+  byte flags;				/* Route flags (RTF_...) */
+  word source_as;			/* Source AS of this route (0=local) */
+  ip_addr gw;				/* Next hop */
+  struct iface *iface;			/* Outgoing interface */
+  struct ea_list *attrs;		/* Extended Attribute chain */
+} 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 */
+#define RTS_OSPF_BOUNDARY 11		/* OSPF route to boundary router */
+#define RTS_BGP 12			/* BGP route */
+
+#define SCOPE_HOST 0			/* Address scope */
+#define SCOPE_LINK 0x10
+#define SCOPE_SITE 0x80
+#define SCOPE_UNIVERSE 0xff
+
+#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 */
+
+/*
+ *	Extended Route Attributes
+ */
+
+typedef struct eattr {
+  byte protocol;			/* Protocol ID (EAP_...) */
+  byte flags;				/* Attribute flags (EAF_...) */
+  byte id;				/* Protocol-dependent ID */
+  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 */
+  byte sorted;				/* `Really sorted' flag */
+  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));		\
+	memset(p, sizeof(ea_list));				\
+	p->nattrs = cnt;					\
+} while(0)
+
+#endif
diff --git a/sysdep/cf/linux-20.h b/sysdep/cf/linux-20.h
new file mode 100644
index 0000000..6100add
--- /dev/null
+++ b/sysdep/cf/linux-20.h
@@ -0,0 +1,11 @@
+/*
+ *	Configuration for Linux 2.0 based systems
+ *
+ *	(c) 1998 Martin Mares <mj@ucw.cz>
+ *
+ *	Can be freely distributed and used under the terms of the GNU GPL.
+ */
+
+#undef CONFIG_TOS
+#undef CONFIG_MULTIPATH
+#undef CONFIG_NETLINK
diff --git a/sysdep/cf/linux-21.h b/sysdep/cf/linux-21.h
new file mode 100644
index 0000000..a2afcbb
--- /dev/null
+++ b/sysdep/cf/linux-21.h
@@ -0,0 +1,11 @@
+/*
+ *	Configuration for Linux 2.1 based systems
+ *
+ *	(c) 1998 Martin Mares <mj@ucw.cz>
+ *
+ *	Can be freely distributed and used under the terms of the GNU GPL.
+ */
+
+#define CONFIG_TOS
+#define CONFIG_MULTIPATH
+#define CONFIG_NETLINK
diff --git a/sysdep/cf/linux-v6.h b/sysdep/cf/linux-v6.h
new file mode 100644
index 0000000..de397fc
--- /dev/null
+++ b/sysdep/cf/linux-v6.h
@@ -0,0 +1,13 @@
+/*
+ *	Configuration for Linux 2.1 based systems running IPv6
+ *
+ *	(c) 1998 Martin Mares <mj@ucw.cz>
+ *
+ *	Can be freely distributed and used under the terms of the GNU GPL.
+ */
+
+#define IPV6
+
+#define CONFIG_TOS
+#define CONFIG_MULTIPATH
+#define CONFIG_NETLINK
diff --git a/sysdep/config.h b/sysdep/config.h
new file mode 100644
index 0000000..e83a508
--- /dev/null
+++ b/sysdep/config.h
@@ -0,0 +1,50 @@
+/*
+ *	This is a manually generated BIRD configuration file.
+ *	It will be replaced by something better when we come
+ *	with an automated configuration mechanism. [mj]
+ */
+
+#ifndef _BIRD_CONFIG_H_
+#define _BIRD_CONFIG_H_
+
+/* System-dependent configuration */
+
+#include <sysdep/cf/linux-20.h>
+
+/* Include debugging code */
+
+#define DEBUG
+
+/* Types */
+
+typedef signed char s8;
+typedef unsigned char u8;
+typedef short int s16;
+typedef unsigned short int u16;
+typedef int s32;
+typedef unsigned int u32;
+
+typedef u8 byte;
+typedef u16 word;
+
+/* Endianity */
+
+#define CPU_LITTLE_ENDIAN
+
+/* Required alignment for multi-byte accesses */
+
+#define CPU_NEEDS_ALIGN_WORD 1
+#define CPU_NEEDS_ALIGN_LONG 1
+
+/* Usual alignment for structures */
+
+#define CPU_STRUCT_ALIGN 4
+
+/* Protocol options */
+
+#define CONFIG_STATIC
+#define CONFIG_RIP
+#define CONFIG_BGP
+#define CONFIG_OSPF
+
+#endif
diff --git a/sysdep/linux/Makefile b/sysdep/linux/Makefile
new file mode 100644
index 0000000..a81db06
--- /dev/null
+++ b/sysdep/linux/Makefile
@@ -0,0 +1 @@
+include $(TOPDIR)/Rules