This is a fundamental change of an original (1999) concept of route
processing inside BIRD. During import/export, there was a temporary
ea_list created which was to be used instead of the another one inside
the route itself.

This led to some confusion, quirks, and strange filter code that handled
extended route attributes. Dropping it now.

The protocol interface has changed in an uniform way -- the
`struct ea_list *attrs` argument has been removed from store_tmp_attrs(),
import_control(), rt_notify() and get_route_info().

This supersedes the EAP_* constants.

Just to make the code a bit more clean and easier to maintain.

Included are Makefile implicit rules to show the preprocessed source.
When debugging something around this, it may be handy.

During route export, the receiving protocol often initialized route
metrics to default value in its import_control hook before export filter
was executed. This is inconsistent with the expectation that an export
filter would process the same route as one in the routing table and it
breaks setting these metrics before (e.g. for static routes directly in
static protocol).

The patch removes the initialization of route metrics in import_control
hook, the default values are already handled in rt_notify hook called
after export filters.

The patch also changed the behavior of OSPF to keep metrics when a route
is reannounced between OSPF instances (to be consistent with other
protocols) and the behavior when both ospf_metric1 and ospf_metric2
are specified (to have more expected behavior).

The patch allows to use 'net.src' to access SADR source prefix
from filters.

Thanks to Toke Hoiland-Jorgensen for the original patch for srclen.

Use full time precision to initialize random generator. The old
code was prone to initialize it to the same values in specific
circumstances (boot without RTC, multiple VMs starting at once).

When a Babel node restarts, it loses its sequence number, which can cause
its routes to be rejected by peers until the state is cleared out by other
nodes in the network (which can take on the order of minutes).

There are two ways to fix this: Having stable storage to keep the sequence
number across restarts, or picking a different router ID each time.

This implements the latter, by introducing a new option that will cause
BIRD to randomize a high 32 bits of router ID every time it starts up.
This avoids the problem at the cost of not having stable router IDs in
the network.

Thanks to Toke Hoiland-Jorgensen for the patch.

The router ID being assigned to routes was a uint, which discards the
upper 32 bits. This also has the nice side effect of echoing the wrong
router ID back to other routers.

Thanks to Toke Hoiland-Jorgensen for the patch.

Thanks to Toke Høiland-Jørgensen <toke@toke.dk> for reporting this bug.

These instructions caused SIGABORTs on reconfiguration.

Implement RFC 7166, crypthographic authentication for OSPFv3
analogous to authentication used for OSPFv2.

For IPv4 with extended next hop, we use MP-BGP format and therefore no
independent NEXT_HOP attribute.

Thanks to Arvin Gan for the bugreport.

Thanks to Arvin Gan for the bugreport.

The old one does not work with 2.0.x.

Thanks to Toke Hoiland-Jorgensen for the bugreport.

Thanks to Joshua McQuistan for the bugreport.

The bgpmask literals can include expressions. This is OK but they have
to be interpreted as soon as the code is run, not in the time the code
is used as value.

This led to strange behavior like rewriting bgpmasks when they shan't
be rewritten:

	function mask_generator(int as)
	{
		return [= * as * =];
	}

	function another()
	bgpmask m1;
	bgpmask m2;
	{
		m1 = mask_generator(10);
		m2 = mask_generator(20);
		if (m1 == m2) {
			print("strange"); # this would happen
		}
	}

Moreover, sending this to CLI would cause stack overflow and knock down the
whole BIRD, as soon as there is at least one route to execute the given
filter on.

	show route filter bgpmask mmm; bgppath ppp; { ppp = +empty+; mmm = [= (ppp ~ mmm) =]; print(mmm); accept; }

The magic match operator (~) inside the bgpmask literal would try to
resolve mmm, which points to the same bgpmask so it would resolve
itself, call the magic match operator and vice versa.

After this patch, the bgpmask literal will get resolved as soon as it's
assigned to mmm and it also will return a type error as bool is not
convertible to ASN in BIRD.

This instruction was removed in the commit linked below
and never used ever again. Rest in peace.

commit 84c7e194
Author: Pavel Machek <pavel@ucw.cz>
Date:   Tue Mar 2 19:49:28 1999 +0000

It was supposed to do tail-recursion in interpret() but it didn't
compile as such. Converting it to loop makes a significant filter
performance improvement for flat filters.

The two-letter instructions were quite messy but they could be easily
read from memory dumps. Now GDB (since 2012) supports pretty printing
enum values and GCC checks the switch construction for missing enum
values so we are converting the nice two-byte values to enums.

Anyway, the enum still keeps the old two-byte values to be able to read
the instruction codes even without GDB from plain memory dump.

Uncommented an old test.