Routes comming through pipe from primary to secondary table were
filtered by both EXPORT and IMPORT filters, but they should be
only filtered by EXPORT filters.

Missing macro leads to not calling some of protocol's
callbacks.

KRF_INSTALLED flag was not cleared during reconfiguration
that lead to not removing routes during reconfigure when
export rules changed.

We also should not try to remove routes we didi not installed,
on Linux this leads to warnings (as kernel checks route source
field and do not allow to remove non-bird routes) but we should
not rely on it.

AS4 optional attribute errors were handled by session
drop (according to BGP RFC). This patch implements
error handling according to new BGP AS4 draft (*)
 - ignoring invalid AS4 optional attributes.

(*) http://www.ietf.org/internet-drafts/draft-chen-rfc4893bis-02.txt

Add 'capabilities' option, change default behavior to advertise ipv4,
add some checks and ignore incoming capabilities when capabilities
are disabled.

This patch extends the length for attributes from 1024 to 2048
(because both AS_PATH and AS4_PATH attributes take 2+4 B per AS).

If there is not enough space for attributes, Bird skips that
route group. Old behavior (skipping remaining attributes)
leads to skipping required attributes and session drop.

When slave was in full state, it didn't retransmit
lost packets. That leads to OSPF connection locked
in states loading-full.

Bird crashed when 'bgp_path.len' was used for routes that does
not came from BGP.

When packet was lost during dbdes exchange, slave did not retransmit
it. That leads to OSPF connection locked in states exchange-exstart.

Scheduling flush must be done before resource pool freeing as it
frees some allocated list nodes from a global list.

Older kernel headers (the ones in Debian Sarge) does not
have __kernel_sockaddr_storage .

When OSPF neighbor state drops down to EXSTART,
clear LSA request and retransmit lists, as specified
by RFC. I hope that this will prevent oscillations
between EXSTART and LOADING states, which sometimes
happened.

It also contains related fix from Yury Shevchuk that
properly resets DB summary list iterator.

Checksum was not recalculated when LSA was changed and
packets with bad checksum were sent.

Missing cases in filter code interpret leads to crash
when  bgp_next_hop attr was queried.

Filter code used 'aux' integer field of 'symbol' struct to store ptr
to next symbol and both 'aux2' and 'def' fields for value.
Changed to just 'def' for value and 'aux2' for ptr to next symbol.
Also another minor bugfix.

When capability related error is received, next connect will be
without capabilities. Also cease error subcodes descriptions
(according to [RFC4486]) are added.

BGP keeps its copy of configuration ptr and didn't update it during
reconfiguration. But old configuration is freed during reconfiguration.
That leads to unnecessary reset of BGP connection during reconfiguration
(old conf is corrupted and therefore different) and possibly other strange
behavior.

Fixes two race conditions causing crash of Bird, several unhandled
cases during BGP initialization, and some other bugs. Also changes
handling of startup delay to be more useful and implement
reporting of last error in 'show protocols' command.

WALK_LIST_DELSAFE (in ev_run_list) is not safe with regard
to deletion of next node. When some events are rescheduled
during event execution, it may lead to deletion of next
node and some events are skipped. Such skipped nodes remain
in temporary list on stack and the last of them contains
'next' pointer to stack area. When this event is later
scheduled, it damages stack area trying to remove it from
the list, which leads to random crashes with funny
backtraces :-) .

executing sk_read().

The core state machine was broken - it didn't free resources
in START -> DOWN transition and might freed resources after
UP -> STOP transition before protocol turned down. It leads
to deadlock on olock acquisition when lock was not freed
during previous stop.

The current behavior is that resources, allocated during
DOWN -> * transition, are freed in * -> DOWN transition,
and flushing (scheduled in UP -> *) just counteract
feeding (scheduled in * -> UP). Protocol fell down
when both flushing is done (if needed) and protocol
reports DOWN.

BTW, is thera a reason why neighbour cache item acquired
by protocol is not tracked by resource mechanism?