bgpd/bgp_io.h

   1 /*
   2   BGP I/O.
   3   Implements a consumer thread to flush packets destined for remote peers.
   4
   5   Copyright (C) 2017  Cumulus Networks
   6
   7   This program is free software; you can redistribute it and/or modify
   8   it under the terms of the GNU General Public License as published by
   9   the Free Software Foundation; either version 2 of the License, or
  10   (at your option) any later version.
  11
  12   This program is distributed in the hope that it will be useful, but
  13   WITHOUT ANY WARRANTY; without even the implied warranty of
  14   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  15   General Public License for more details.
  16
  17   You should have received a copy of the GNU General Public License
  18   along with this program; see the file COPYING; if not, write to the
  19   Free Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston,
  20   MA 02110-1301 USA
  21  */
  22
  23 #ifndef _FRR_BGP_IO_H
  24 #define _FRR_BGP_IO_H
  25
  26 #define BGP_WRITE_PACKET_MAX 10U
  27 #define BGP_READ_PACKET_MAX  10U
  28
  29 #include "bgpd/bgpd.h"
  30 #include "frr_pthread.h"
  31
  32 /**
  33  * Control variable for write thread.
  34  *
  35  * Setting this variable to false will eventually result in thread termination.
  36  */
  37 extern bool bgp_packet_writes_thread_run;
  38
  39 /**
  40  * Initializes data structures and flags for the write thread.
  41  *
  42  * This function should be called from the main thread before
  43  * bgp_writes_start() is invoked.
  44  */
  45 extern void bgp_io_init(void);
  46
  47 /**
  48  * Start function for write thread.
  49  *
  50  * @param arg - unused
  51  */
  52 extern void *bgp_io_start(void *arg);
  53
  54 /**
  55  * Start function for write thread.
  56  *
  57  * Uninitializes all resources and stops the thread.
  58  *
  59  * @param result - where to store data result, unused
  60  */
  61 extern int bgp_io_stop(void **result, struct frr_pthread *fpt);
  62
  63 /**
  64  * Turns on packet writing for a peer.
  65  *
  66  * After this function is called, any packets placed on peer->obuf will be
  67  * written to peer->fd at regular intervals. Additionally it becomes unsafe to
  68  * use peer->fd with select() or poll().
  69  *
  70  * This function increments the peer reference counter with peer_lock().
  71  *
  72  * If the peer is already registered, nothing happens.
  73  *
  74  * @param peer - peer to register
  75  */
  76 extern void bgp_writes_on(struct peer *peer);
  77
  78 /**
  79  * Turns off packet writing for a peer.
  80  *
  81  * After this function is called, any packets placed on peer->obuf will not be
  82  * written to peer->fd. After this function returns it is safe to use peer->fd
  83  * with select() or poll().
  84  *
  85  * If the flush = true, a last-ditch effort will be made to flush any remaining
  86  * packets to peer->fd. Upon encountering any error whatsoever, the attempt
  87  * will abort. If the caller wishes to know whether the flush succeeded they
  88  * may check peer->obuf->count against zero.
  89  *
  90  * If the peer is not registered, nothing happens.
  91  *
  92  * @param peer - peer to deregister
  93  * @param flush - as described
  94  */
  95 extern void bgp_writes_off(struct peer *peer);
  96
  97 /**
  98  * Turns on packet reading for a peer.
  99  *
 100  * After this function is called, any packets received on peer->fd will be read
 101  * and copied into the FIFO queue peer->ibuf. Additionally it becomes unsafe to
 102  * use peer->fd with select() or poll().
 103  *
 104  * When a full packet is read, bgp_process_packet() will be scheduled on the
 105  * main thread.
 106  *
 107  * This function increments the peer reference counter with peer_lock().
 108  *
 109  * If the peer is already registered, nothing happens.
 110  *
 111  * @param peer - peer to register
 112  */
 113 extern void bgp_reads_on(struct peer *peer);
 114
 115 /**
 116  * Turns off packet reading for a peer.
 117  *
 118  * After this function is called, any packets received on peer->fd will not be
 119  * read. After this function returns it is safe to use peer->fd with select()
 120  * or poll().
 121  *
 122  * This function decrements the peer reference counter with peer_unlock().
 123  *
 124  * If the peer is not registered, nothing happens.
 125  *
 126  * @param peer - peer to deregister
 127  */
 128 extern void bgp_reads_off(struct peer *peer);
 129
 130 #endif /* _FRR_BGP_IO_H */