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48bc232f08
This option allows to keep the received next hop even in cases when the route is sent to an interface with a different subnet.
317 lines
13 KiB
C
317 lines
13 KiB
C
/*
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* BIRD -- The Border Gateway Protocol
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*
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* (c) 2000 Martin Mares <mj@ucw.cz>
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*
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* Can be freely distributed and used under the terms of the GNU GPL.
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*/
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#ifndef _BIRD_BGP_H_
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#define _BIRD_BGP_H_
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#include <stdint.h>
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#include "nest/route.h"
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struct linpool;
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struct eattr;
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struct bgp_config {
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struct proto_config c;
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u32 local_as, remote_as;
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ip_addr remote_ip;
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ip_addr source_addr; /* Source address to use */
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struct iface *iface; /* Interface for link-local addresses */
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int multihop; /* Number of hops if multihop */
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int ttl_security; /* Enable TTL security [RFC5082] */
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int next_hop_self; /* Always set next hop to local IP address */
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int next_hop_keep; /* Do not touch next hop attribute */
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int missing_lladdr; /* What we will do when we don' know link-local addr, see MLL_* */
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int gw_mode; /* How we compute route gateway from next_hop attr, see GW_* */
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int compare_path_lengths; /* Use path lengths when selecting best route */
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int med_metric; /* Compare MULTI_EXIT_DISC even between routes from differen ASes */
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int igp_metric; /* Use IGP metrics when selecting best route */
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int prefer_older; /* Prefer older routes according to RFC 5004 */
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int deterministic_med; /* Use more complicated algo to have strict RFC 4271 MED comparison */
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u32 default_local_pref; /* Default value for LOCAL_PREF attribute */
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u32 default_med; /* Default value for MULTI_EXIT_DISC attribute */
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int capabilities; /* Enable capability handshake [RFC3392] */
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int enable_refresh; /* Enable local support for route refresh [RFC2918] */
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int enable_as4; /* Enable local support for 4B AS numbers [RFC4893] */
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u32 rr_cluster_id; /* Route reflector cluster ID, if different from local ID */
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int rr_client; /* Whether neighbor is RR client of me */
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int rs_client; /* Whether neighbor is RS client of me */
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int advertise_ipv4; /* Whether we should add IPv4 capability advertisement to OPEN message */
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int passive; /* Do not initiate outgoing connection */
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int interpret_communities; /* Hardwired handling of well-known communities */
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int secondary; /* Accept also non-best routes (i.e. RA_ACCEPTED) */
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unsigned connect_retry_time;
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unsigned hold_time, initial_hold_time;
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unsigned keepalive_time;
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unsigned start_delay_time; /* Minimum delay between connects */
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unsigned error_amnesia_time; /* Errors are forgotten after */
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unsigned error_delay_time_min; /* Time to wait after an error is detected */
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unsigned error_delay_time_max;
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unsigned disable_after_error; /* Disable the protocol when error is detected */
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char *password; /* Password used for MD5 authentication */
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struct rtable_config *igp_table; /* Table used for recursive next hop lookups */
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};
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#define MLL_SELF 1
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#define MLL_DROP 2
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#define MLL_IGNORE 3
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#define GW_DIRECT 1
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#define GW_RECURSIVE 2
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struct bgp_conn {
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struct bgp_proto *bgp;
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struct birdsock *sk;
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unsigned int state; /* State of connection state machine */
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struct timer *connect_retry_timer;
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struct timer *hold_timer;
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struct timer *keepalive_timer;
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struct event *tx_ev;
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int packets_to_send; /* Bitmap of packet types to be sent */
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int notify_code, notify_subcode, notify_size;
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byte *notify_data;
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u32 advertised_as; /* Temporary value for AS number received */
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int start_state; /* protocol start_state snapshot when connection established */
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int want_as4_support; /* Connection tries to establish AS4 session */
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int peer_as4_support; /* Peer supports 4B AS numbers [RFC4893] */
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int peer_refresh_support; /* Peer supports route refresh [RFC2918] */
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unsigned hold_time, keepalive_time; /* Times calculated from my and neighbor's requirements */
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};
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struct bgp_proto {
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struct proto p;
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struct bgp_config *cf; /* Shortcut to BGP configuration */
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u32 local_as, remote_as;
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int start_state; /* Substates that partitions BS_START */
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int is_internal; /* Internal BGP connection (local_as == remote_as) */
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int as4_session; /* Session uses 4B AS numbers in AS_PATH (both sides support it) */
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u32 local_id; /* BGP identifier of this router */
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u32 remote_id; /* BGP identifier of the neighbor */
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u32 rr_cluster_id; /* Route reflector cluster ID */
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int rr_client; /* Whether neighbor is RR client of me */
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int rs_client; /* Whether neighbor is RS client of me */
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struct bgp_conn *conn; /* Connection we have established */
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struct bgp_conn outgoing_conn; /* Outgoing connection we're working with */
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struct bgp_conn incoming_conn; /* Incoming connection we have neither accepted nor rejected yet */
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struct object_lock *lock; /* Lock for neighbor connection */
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struct neighbor *neigh; /* Neighbor entry corresponding to remote ip, NULL if multihop */
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ip_addr source_addr; /* Local address used as an advertised next hop */
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rtable *igp_table; /* Table used for recursive next hop lookups */
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struct event *event; /* Event for respawning and shutting process */
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struct timer *startup_timer; /* Timer used to delay protocol startup due to previous errors (startup_delay) */
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struct bgp_bucket **bucket_hash; /* Hash table of attribute buckets */
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unsigned int hash_size, hash_count, hash_limit;
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struct fib prefix_fib; /* Prefixes to be sent */
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list bucket_queue; /* Queue of buckets to send */
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struct bgp_bucket *withdraw_bucket; /* Withdrawn routes */
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unsigned startup_delay; /* Time to delay protocol startup by due to errors */
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bird_clock_t last_proto_error; /* Time of last error that leads to protocol stop */
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u8 last_error_class; /* Error class of last error */
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u32 last_error_code; /* Error code of last error. BGP protocol errors
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are encoded as (bgp_err_code << 16 | bgp_err_subcode) */
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#ifdef IPV6
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byte *mp_reach_start, *mp_unreach_start; /* Multiprotocol BGP attribute notes */
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unsigned mp_reach_len, mp_unreach_len;
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ip_addr local_link; /* Link-level version of source_addr */
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#endif
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};
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struct bgp_prefix {
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struct fib_node n; /* Node in prefix fib */
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node bucket_node; /* Node in per-bucket list */
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};
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struct bgp_bucket {
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node send_node; /* Node in send queue */
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struct bgp_bucket *hash_next, *hash_prev; /* Node in bucket hash table */
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unsigned hash; /* Hash over extended attributes */
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list prefixes; /* Prefixes in this buckets */
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ea_list eattrs[0]; /* Per-bucket extended attributes */
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};
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#define BGP_PORT 179
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#define BGP_VERSION 4
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#define BGP_HEADER_LENGTH 19
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#define BGP_MAX_PACKET_LENGTH 4096
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#define BGP_RX_BUFFER_SIZE 4096
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#define BGP_TX_BUFFER_SIZE BGP_MAX_PACKET_LENGTH
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extern struct linpool *bgp_linpool;
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void bgp_start_timer(struct timer *t, int value);
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void bgp_check_config(struct bgp_config *c);
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void bgp_error(struct bgp_conn *c, unsigned code, unsigned subcode, byte *data, int len);
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void bgp_close_conn(struct bgp_conn *c);
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void bgp_update_startup_delay(struct bgp_proto *p);
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void bgp_conn_enter_openconfirm_state(struct bgp_conn *conn);
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void bgp_conn_enter_established_state(struct bgp_conn *conn);
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void bgp_conn_enter_close_state(struct bgp_conn *conn);
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void bgp_conn_enter_idle_state(struct bgp_conn *conn);
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void bgp_store_error(struct bgp_proto *p, struct bgp_conn *c, u8 class, u32 code);
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void bgp_stop(struct bgp_proto *p, unsigned subcode);
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#ifdef LOCAL_DEBUG
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#define BGP_FORCE_DEBUG 1
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#else
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#define BGP_FORCE_DEBUG 0
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#endif
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#define BGP_TRACE(flags, msg, args...) do { if ((p->p.debug & flags) || BGP_FORCE_DEBUG) \
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log(L_TRACE "%s: " msg, p->p.name , ## args ); } while(0)
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#define BGP_TRACE_RL(rl, flags, msg, args...) do { if ((p->p.debug & flags) || BGP_FORCE_DEBUG) \
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log_rl(rl, L_TRACE "%s: " msg, p->p.name , ## args ); } while(0)
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/* attrs.c */
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/* Hack: although BA_NEXT_HOP attribute has type EAF_TYPE_IP_ADDRESS, in IPv6
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* we store two addesses in it - a global address and a link local address.
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*/
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#ifdef IPV6
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#define NEXT_HOP_LENGTH (2*sizeof(ip_addr))
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static inline void set_next_hop(byte *b, ip_addr addr) { ((ip_addr *) b)[0] = addr; ((ip_addr *) b)[1] = IPA_NONE; }
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#else
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#define NEXT_HOP_LENGTH sizeof(ip_addr)
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static inline void set_next_hop(byte *b, ip_addr addr) { ((ip_addr *) b)[0] = addr; }
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#endif
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void bgp_attach_attr(struct ea_list **to, struct linpool *pool, unsigned attr, uintptr_t val);
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byte *bgp_attach_attr_wa(struct ea_list **to, struct linpool *pool, unsigned attr, unsigned len);
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struct rta *bgp_decode_attrs(struct bgp_conn *conn, byte *a, unsigned int len, struct linpool *pool, int mandatory);
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int bgp_get_attr(struct eattr *e, byte *buf, int buflen);
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int bgp_rte_better(struct rte *, struct rte *);
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int bgp_rte_recalculate(rtable *table, net *net, rte *new, rte *old, rte *old_best);
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void bgp_rt_notify(struct proto *P, rtable *tbl UNUSED, net *n, rte *new, rte *old UNUSED, ea_list *attrs);
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int bgp_import_control(struct proto *, struct rte **, struct ea_list **, struct linpool *);
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void bgp_attr_init(struct bgp_proto *);
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unsigned int bgp_encode_attrs(struct bgp_proto *p, byte *w, ea_list *attrs, int remains);
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void bgp_free_bucket(struct bgp_proto *p, struct bgp_bucket *buck);
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void bgp_get_route_info(struct rte *, byte *buf, struct ea_list *attrs);
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inline static void bgp_attach_attr_ip(struct ea_list **to, struct linpool *pool, unsigned attr, ip_addr a)
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{ *(ip_addr *) bgp_attach_attr_wa(to, pool, attr, sizeof(ip_addr)) = a; }
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/* packets.c */
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void mrt_dump_bgp_state_change(struct bgp_conn *conn, unsigned old, unsigned new);
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void bgp_schedule_packet(struct bgp_conn *conn, int type);
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void bgp_kick_tx(void *vconn);
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void bgp_tx(struct birdsock *sk);
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int bgp_rx(struct birdsock *sk, int size);
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const char * bgp_error_dsc(unsigned code, unsigned subcode);
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void bgp_log_error(struct bgp_proto *p, u8 class, char *msg, unsigned code, unsigned subcode, byte *data, unsigned len);
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/* Packet types */
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#define PKT_OPEN 0x01
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#define PKT_UPDATE 0x02
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#define PKT_NOTIFICATION 0x03
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#define PKT_KEEPALIVE 0x04
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#define PKT_ROUTE_REFRESH 0x05
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#define PKT_SCHEDULE_CLOSE 0x1f /* Used internally to schedule socket close */
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/* Attributes */
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#define BAF_OPTIONAL 0x80
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#define BAF_TRANSITIVE 0x40
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#define BAF_PARTIAL 0x20
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#define BAF_EXT_LEN 0x10
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#define BA_ORIGIN 0x01 /* [RFC1771] */ /* WM */
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#define BA_AS_PATH 0x02 /* WM */
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#define BA_NEXT_HOP 0x03 /* WM */
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#define BA_MULTI_EXIT_DISC 0x04 /* ON */
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#define BA_LOCAL_PREF 0x05 /* WD */
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#define BA_ATOMIC_AGGR 0x06 /* WD */
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#define BA_AGGREGATOR 0x07 /* OT */
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#define BA_COMMUNITY 0x08 /* [RFC1997] */ /* OT */
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#define BA_ORIGINATOR_ID 0x09 /* [RFC1966] */ /* ON */
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#define BA_CLUSTER_LIST 0x0a /* ON */
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/* We don't support these: */
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#define BA_DPA 0x0b /* ??? */
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#define BA_ADVERTISER 0x0c /* [RFC1863] */
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#define BA_RCID_PATH 0x0d
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#define BA_MP_REACH_NLRI 0x0e /* [RFC2283] */
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#define BA_MP_UNREACH_NLRI 0x0f
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#define BA_EXT_COMMUNITY 0x10 /* [RFC4360] */
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#define BA_AS4_PATH 0x11 /* [RFC4893] */
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#define BA_AS4_AGGREGATOR 0x12
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/* BGP connection states */
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#define BS_IDLE 0
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#define BS_CONNECT 1 /* Attempting to connect */
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#define BS_ACTIVE 2 /* Waiting for connection retry & listening */
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#define BS_OPENSENT 3
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#define BS_OPENCONFIRM 4
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#define BS_ESTABLISHED 5
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#define BS_CLOSE 6 /* Used during transition to BS_IDLE */
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/* BGP start states
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*
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* Used in PS_START for fine-grained specification of starting state.
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*
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* When BGP protocol is started by core, it goes to BSS_PREPARE. When BGP protocol
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* done what is neccessary to start itself (like acquiring the lock), it goes to BSS_CONNECT.
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* When some connection attempt failed because of option or capability error, it goes to
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* BSS_CONNECT_NOCAP.
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*/
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#define BSS_PREPARE 0 /* Used before ordinary BGP started, i. e. waiting for lock */
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#define BSS_DELAY 1 /* Startup delay due to previous errors */
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#define BSS_CONNECT 2 /* Ordinary BGP connecting */
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#define BSS_CONNECT_NOCAP 3 /* Legacy BGP connecting (without capabilities) */
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/* Error classes */
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#define BE_NONE 0
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#define BE_MISC 1 /* Miscellaneous error */
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#define BE_SOCKET 2 /* Socket error */
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#define BE_BGP_RX 3 /* BGP protocol error notification received */
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#define BE_BGP_TX 4 /* BGP protocol error notification sent */
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#define BE_AUTO_DOWN 5 /* Automatic shutdown */
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#define BE_MAN_DOWN 6 /* Manual shutdown */
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/* Misc error codes */
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#define BEM_NEIGHBOR_LOST 1
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#define BEM_INVALID_NEXT_HOP 2
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#define BEM_INVALID_MD5 3 /* MD5 authentication kernel request failed (possibly not supported) */
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#define BEM_NO_SOCKET 4
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/* Automatic shutdown error codes */
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#define BEA_ROUTE_LIMIT_EXCEEDED 1
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/* Well-known communities */
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#define BGP_COMM_NO_EXPORT 0xffffff01 /* Don't export outside local AS / confed. */
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#define BGP_COMM_NO_ADVERTISE 0xffffff02 /* Don't export at all */
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#define BGP_COMM_NO_EXPORT_SUBCONFED 0xffffff03 /* NO_EXPORT even in local confederation */
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/* Origins */
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#define ORIGIN_IGP 0
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#define ORIGIN_EGP 1
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#define ORIGIN_INCOMPLETE 2
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/* Address families */
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#define BGP_AF_IPV4 1
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#define BGP_AF_IPV6 2
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#ifdef IPV6
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#define BGP_AF BGP_AF_IPV6
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#else
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#define BGP_AF BGP_AF_IPV4
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#endif
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#endif
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