The new kernel syncer is cleanly split between generic UNIX module
and OS dependent submodules:
- krt.c (the generic part)
- krt-iface (low-level functions for interface handling)
- krt-scan (low-level functions for routing table scanning)
- krt-set (low-level functions for setting of kernel routes)
krt-set and krt-iface are common for all BSD-like Unices, krt-scan is heavily
system dependent (most Unices require /dev/kmem parsing, Linux uses /proc),
Netlink substitues all three modules.
We expect each UNIX port supports kernel routing table scanning, kernel
interface table scanning, kernel route manipulation and possibly also
asynchronous event notifications (new route, interface state change;
not implemented yet) and build the KRT protocol on the top of these
primitive operations.
o Introduced if_find_by_index()
o Recognizing two types of interface updates: full update (starting with
if_start_update(), ending with if_end_update(), guaranteed to see
all existing interfaces) and a partial update (only if_update(),
usually due to asynchronous interface notifications).
o Introduced IF_LINK_UP flag corresponding to real link state.
o Allowed addressless interfaces.
o IF_UP is now automatically calculated and set iff the interface
is administratively up, has link up and has an IP address assigned.
It may be IF_IGNORED, though (as in case of the loopback).
o Any changes which include up/down transition are considered small
enough to not provoke artificial upping and downing of the interface.
o When an interface disappears (i.e., it wasn't seen in the last scan),
we announce this change only once.
o IF_LOOPBACK implies IF_IGNORE.
of various callbacks.
Events are just another resource type objects (thus automatically freed
and unlinked when the protocol using them shuts down). Each event can
be linked in at most one event list. For most purposes, just use the
global event list handled by the following functions:
ev_schedule Schedule event to be called at the next event
scheduling point. If the event was already
scheduled, it's just re-linked to the end of the list.
ev_postpone Postpone an already scheduled event, so that it
won't get called. Postponed events can be scheduled
again by ev_schedule().
You can also create custom event lists to build your own synchronization
primitives. Just use:
ev_init_list to initialize an event list
ev_enqueue to schedule event on specified event list
ev_postpone works as well for custom lists
ev_run_list to run all events on your custom list
ev_run to run a specific event and dequeue it
#define L_DEBUG "\001" /* Debugging messages */
#define L_INFO "\002" /* Informational messages */
#define L_WARN "\003" /* Warnings */
#define L_ERR "\004" /* Errors */
#define L_AUTH "\005" /* Authorization failed etc. */
#define L_FATAL "\006" /* Fatal errors */
#define L_TRACE "\002" /* Protocol tracing */
#define L_INFO "\003" /* Informational messages */
#define L_REMOTE "\004" /* Remote protocol errors */
#define L_WARN "\004" /* Local warnings */
#define L_ERR "\005" /* Local errors */
#define L_AUTH "\006" /* Authorization failed etc. */
#define L_FATAL "\007" /* Fatal errors */
#define L_BUG "\010" /* BIRD bugs */
Introduced bug() which is like die(), but with level L_BUG. Protocols
should _never_ call die() as it should be used only during initialization
and on irrecoverable catastrophic events like out of memory.
Also introduced ASSERT() which behaves like normal assert(), but it calls
bug() when assertion fails. When !defined(DEBUGGING), it gets ignored.
o Interface syncing is now a part of krt and it can have configurable
parameters. Actually, the only one is scan rate now :)
o Kernel routing table syncing is now synchronized with interface
syncing (we need the most recent version of the interface list
to prevent lots of routes to non-existent destinations from
appearing). Instead of its own timer, we just check if it's
route scan time after each iface list scan.
o Syncing of device routes implemented.
o CONFIG_AUTO_ROUTES should control syncing of automatic device routes.
o Rewrote krt_remove_route() to really remove routes :)
o Better diagnostics.
o Fixed a couple of bugs.
regular interface addresses" rule).
Protocols should NOT rely on router_id existence -- when router ID is not
available, the router_id variable is set to zero and protocols requiring
valid router ID should just refuse to start, reporting such error to the log.
the kernel routing table as opposed to modifying it which is approximately
the same on non-netlink systems, I've split the kernel routing table
routines to read and write parts. To be implemented later ;-)
protocols and don't send route/interface updates to them and when they come up,
we resend the whole route/interface tables privately.
Removed the "scan interface list after protocol start" work-around.
this happens, don't reject the whole interface, just mark it as index 0.
o Removed Pavel's comment about EFAULT and SIGSEGV. EFAULT is a valid return
code for cases where the buffer is too small.
o Commented out the smart interface list size logic temporarily as it seems
Linux 2.0 SIOCGIFCONF doesn't react to ifc_req==NULL sanely. Replaced it
by exponential stepping.
