Merge commit 'c980f800' into integrated

  c->load_time = now;

  c->tf_route = c->tf_proto = (struct timeformat){"%T", "%F", 20*3600};

  c->tf_base = c->tf_log = (struct timeformat){"%F %T", NULL, 0};

  c->gr_wait = DEFAULT_GR_WAIT;

  return c;

}

  struct timeformat tf_proto;		/* Time format for 'show protocol' */

  struct timeformat tf_log;		/* Time format for the logfile */

  struct timeformat tf_base;		/* Time format for other purposes */

  u32 gr_wait;				/* Graceful restart wait timeout */

  int cli_debug;			/* Tracing of CLI connections and commands */

  char *err_msg;			/* Parser error message */

	<tag>-f</tag>

	run bird in foreground.

	<tag>-R</tag>

	apply graceful restart recovery after start.

</descrip>

<p>BIRD writes messages about its work to log files or syslog (according to config).

standard library, privileges to read the config file and create the

control socket and the CAP_NET_* capabilities.

<chapt>About routing tables

<p>BIRD has one or more routing tables which may or may not be

shown sorted in <cf/show route/, minor disadvantage is that it is

slightly more computationally expensive.

<sect>Graceful restart

<p>When BIRD is started after restart or crash, it repopulates routing tables in

an uncoordinated manner, like after clean start. This may be impractical in some

cases, because if the forwarding plane (i.e. kernel routing tables) remains

intact, then its synchronization with BIRD would temporarily disrupt packet

forwarding until protocols converge. Graceful restart is a mechanism that could

help with this issue. Generally, it works by starting protocols and letting them

repopulate routing tables while deferring route propagation until protocols

acknowledge their convergence. Note that graceful restart behavior have to be

configured for all relevant protocols and requires protocol-specific support

(currently implemented for Kernel and BGP protocols), it is activated for

particular boot by option <cf/-R/.

<chapt>Configuration

	would accept IPv6 routes only). Such behavior was default in

	older versions of BIRD.

	<tag>graceful restart wait <m/number/</tag>

	During graceful restart recovery, BIRD waits for convergence of routing

	protocols. This option allows to specify a timeout for the recovery to

	prevent waiting indefinitely if some protocols cannot converge. Default:

	240 seconds.

	<tag>timeformat route|protocol|base|log "<m/format1/" [<m/limit/ "<m/format2/"]</tag>

	This option allows to specify a format of date/time used by

	BIRD.  The first argument specifies for which purpose such

(RFC 4360<htmlurl url="ftp://ftp.rfc-editor.org/in-notes/rfc4360.txt">),

route reflectors 

(RFC 4456<htmlurl url="ftp://ftp.rfc-editor.org/in-notes/rfc4456.txt">),

graceful restart

(RFC 4724<htmlurl url="ftp://ftp.rfc-editor.org/in-notes/rfc4724.txt">),

multiprotocol extensions

(RFC 4760<htmlurl url="ftp://ftp.rfc-editor.org/in-notes/rfc4760.txt">),

4B AS numbers 

For IPv6, it uses the standard multiprotocol extensions defined in

RFC 2283<htmlurl url="ftp://ftp.rfc-editor.org/in-notes/rfc2283.txt">

including changes described in the

latest draft<htmlurl url="ftp://ftp.rfc-editor.org/internet-drafts/draft-ietf-idr-bgp4-multiprotocol-v2-05.txt">

RFC 4760<htmlurl url="ftp://ftp.rfc-editor.org/in-notes/rfc4760.txt">

and applied to IPv6 according to

RFC 2545<htmlurl url="ftp://ftp.rfc-editor.org/in-notes/rfc2545.txt">.

	capability and accepts such requests. Even when disabled, BIRD

	can send route refresh requests. Default: on.

	<tag>graceful restart <m/switch/|aware</tag>

	When a BGP speaker restarts or crashes, neighbors will discard all

	received paths from the speaker, which disrupts packet forwarding even

	when the forwarding plane of the speaker remains intact. RFC 4724

	specifies an optional graceful restart mechanism to alleviate this

	issue. This option controls the mechanism. It has three states:

	Disabled, when no support is provided. Aware, when the graceful restart

	support is announced and the support for restarting neighbors is

	provided, but no local graceful restart is allowed (i.e. receiving-only

	role). Enabled, when the full graceful restart support is provided

	(i.e. both restarting and receiving role). Note that proper support for

	local graceful restart requires also configuration of other protocols.

	Default: aware.

	<tag>graceful restart time <m/number/</tag>

	The restart time is announced in the BGP graceful restart capability

	and specifies how long the neighbor would wait for the BGP session to

	re-establish after a restart before deleting stale routes. Default:

	120 seconds.

	<tag>interpret communities <m/switch/</tag> RFC 1997 demands

	that BGP speaker should process well-known communities like

	no-export (65535, 65281) or no-advertise (65535, 65282). For

<sect1>Configuration

<p><descrip>

	<tag>persist <m/switch/</tag> Tell BIRD to leave all its routes in the

	routing tables when it exits (instead of cleaning them up).

	<tag>scan time <m/number/</tag> Time in seconds between two consecutive scans of the

	kernel routing table.

	<tag>learn <m/switch/</tag> Enable learning of routes added to the kernel

	routing tables by other routing daemons or by the system administrator.

	This is possible only on systems which support identification of route

	authorship.

	<tag>device routes <m/switch/</tag> Enable export of device

	routes to the kernel routing table. By default, such routes

	are rejected (with the exception of explicitly configured

	device routes from the static protocol) regardless of the

	export filter to protect device routes in kernel routing table

	(managed by OS itself) from accidental overwriting or erasing.

	<tag>kernel table <m/number/</tag> Select which kernel table should

	this particular instance of the Kernel protocol work with. Available

	only on systems supporting multiple routing tables.

	<tag>persist <m/switch/</tag>

	Tell BIRD to leave all its routes in the routing tables when it exits

	(instead of cleaning them up).

	<tag>scan time <m/number/</tag>

	Time in seconds between two consecutive scans of the kernel routing

	table.

	<tag>learn <m/switch/</tag>

	Enable learning of routes added to the kernel routing tables by other

	routing daemons or by the system administrator. This is possible only on

	systems which support identification of route authorship.

	<tag>device routes <m/switch/</tag>

	Enable export of device routes to the kernel routing table. By default,

	such routes are rejected (with the exception of explicitly configured

	device routes from the static protocol) regardless of the export filter

	to protect device routes in kernel routing table (managed by OS itself)

	from accidental overwriting or erasing.

	<tag>kernel table <m/number/</tag>

	Select which kernel table should this particular instance of the Kernel

	protocol work with. Available only on systems supporting multiple

	routing tables.

	<tag>graceful restart <m/switch/</tag>

	Participate in graceful restart recovery. If this option is enabled and

	a graceful restart recovery is active, the Kernel protocol will defer

	synchronization of routing tables until the end of the recovery. Note

	that import of kernel routes to BIRD is not affected.

</descrip>

<sect1>Attributes

0021	Undo requested

0022	Undo scheduled

0023	Evaluation of expression

0024	Graceful restart status report

1000	BIRD version

1001	Interface list

#define NODE_NEXT(n) ((void *)((NODE (n))->next))

#define NODE_VALID(n) ((NODE (n))->next)

#define WALK_LIST(n,list) for(n=HEAD(list); NODE_VALID(n); n=NODE_NEXT(n))

#define WALK_LIST2(n,nn,list,pos) \

  for(nn=(list).head; NODE_VALID(nn) && (n=SKIP_BACK(typeof(*n),pos,nn)); nn=nn->next)

#define WALK_LIST_DELSAFE(n,nxt,list) \

     for(n=HEAD(list); nxt=NODE_NEXT(n); n=(void *) nxt)

/* WALK_LIST_FIRST supposes that called code removes each processed node */