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 #include "bgpd/bgpd.h"
  27
  28 /**
  29  * Control variable for write thread.
  30  *
  31  * Setting this variable to false and calling peer_writes_wake() will
  32  * eventually result in thread termination.
  33  */
  34 extern bool bgp_packet_writes_thread_run;
  35
  36 /**
  37  * Initializes data structures and flags for the write thread.
  38  *
  39  * This function should be called from the main thread before
  40  * peer_writes_start() is invoked.
  41  */
  42 extern void peer_writes_init(void);
  43
  44 /**
  45  * Start function for write thread.
  46  *
  47  * This function should be passed to pthread_create() during BGP startup.
  48  */
  49 extern void *peer_writes_start(void *arg);
  50
  51 /**
  52  * Start function for write thread.
  53  *
  54  * Uninitializes all resources and stops the thread.
  55  *
  56  * @param result -- where to store data result, unused
  57  */
  58 extern int peer_writes_stop(void **result);
  59
  60 /**
  61  * Registers a peer with the write thread.
  62  *
  63  * This function adds the peer to an internal data structure, which must be
  64  * locked for write access. This call will block until the structure can be
  65  * locked.
  66  *
  67  * After this function is called, any packets placed on peer->obuf will be
  68  * written to peer->fd at regular intervals.
  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 peer_writes_on(struct peer *peer);
  77
  78 /**
  79  * Deregisters a peer with the write thread.
  80  *
  81  * This function removes the peer from an internal data structure, which must
  82  * be locked for write access. This call will block until the structure can be
  83  * locked.
  84  *
  85  * After this function is called, any packets placed on peer->obuf will not be
  86  * written to peer->fd.
  87  *
  88  * This function decrements the peer reference counter with peer_unlock().
  89  *
  90  * If the peer is not registered, nothing happens.
  91  *
  92  * @param peer - peer to deregister
  93  */
  94 extern void peer_writes_off(struct peer *peer);
  95
  96 /**
  97  * Notifies the write thread that there is work to be done.
  98  *
  99  * This function has the effect of waking the write thread if it is sleeping.
 100  * If the thread is not sleeping, this signal will be ignored.
 101  */
 102 extern void peer_writes_wake(void);
 103
 104 #endif /* _FRR_BGP_IO_H */