bgp: add bgpspaker module for non Ryu application usage

This enables you to use Ryu BGP feature as 'bgp speaker' python
library, that is, without ryu-manager, RPC API, REST API, or other Ryu
stuff, you can use Ryu BGP feature in your python application (just
import bgpspeaker.py). The sample code and the API reference docs are
included too.

Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Reviewed-by: YAMAMOTO Takashi <yamamoto@valinux.co.jp>

1 files changed, 44 insertions, 0 deletions

diff --git a/doc/source/library_bgp_speaker.rst b/doc/source/library_bgp_speaker.rst
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+*******************
+BGP speaker library
+*******************
+
+Introduction
+============
+
+Ryu BGP speaker library helps you to enable your code to speak BGP
+protocol. The library supports ipv4, ipv4 vpn, and ipv6 vpn address
+families.
+
+Example
+=======
+
+The following simple code creates a BGP instance with AS number 64512
+and Router ID 10.0.0.1. It tries to establish a bgp session with a
+peer (its IP is 192.168.177.32 and the AS number is 64513). The
+instance advertizes some prefixes.
+
+.. code-block:: python
+
+    import eventlet
+    from ryu.services.protocols.bgp.bgpspeaker import BGPSpeaker
+        
+    def dump_remote_best_path_change(event):
+        print 'the best path changed:', event.remote_as, event.prefix,\
+            event.nexthop, event.is_withdraw
+
+    if __name__ == "__main__":
+        speaker = BGPSpeaker(as_number=64512, router_id='10.0.0.1',
+                             best_path_change_handler=dump_remote_best_path_change)
+        
+        speaker.neighbor_add('192.168.177.32', 64513)
+    
+        count = 1
+        while True:
+            eventlet.sleep(30)
+            prefix = '10.20.' + str(count) + '.0/24'
+            print "add a new prefix", prefix
+            speaker.prefix_add(prefix)
+            count += 1
+            if count == 4:
+                speaker.shutdown()
+                break