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.
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.
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.
