diff options
| -rw-r--r-- | nest/rt-table.c | 31 |
1 files changed, 29 insertions, 2 deletions
diff --git a/nest/rt-table.c b/nest/rt-table.c index 4649132c..de4d4f58 100644 --- a/nest/rt-table.c +++ b/nest/rt-table.c @@ -227,6 +227,24 @@ do_rte_announce(struct announce_hook *a, net *net, rte *new, rte *old, ea_list * rte_free(old); } +/** + * rte_announce - announce a routing table change + * @tab: table the route has been added to + * @net: network in question + * @new: the new route to be announced + * @old: previous optimal route for the same network + * @tmpa: a list of temporary attributes belonging to the new route + * + * This function gets a routing table update and announces it + * to all protocols connected to the same table by their announcement hooks. + * + * For each such protocol, we first call its import_control() hook which + * performs basic checks on the route (each protocol has a right to veto + * or force accept of the route before any filter is asked) and adds default + * values of attributes specific to the new protocol (metrics, tags etc.). + * Then it consults the protocol's export filter and if it accepts the + * route, the rt_notify() hook of the protocol gets called. + */ static void rte_announce(rtable *tab, net *net, rte *new, rte *old, ea_list *tmpa) { @@ -435,10 +453,19 @@ rte_update_unlock(void) * rta_clone()), call rte_get_temp() to obtain a temporary &rte, fill in all * the appropriate data and finally submit the new &rte by calling rte_update(). * - * rte_update() will automatically find the old route defined by the protocol @p + * When rte_update() gets any route, it automatically validates it (checks, + * whether the network and next hop address are valid IP addresses and also + * whether a normal routing protocol doesn't try to smuggle a host or link + * scope route to the table), converts all protocol dependent attributes stored + * in the &rte to temporary extended attributes, consults import filters of the + * protocol to see if the route should be accepted and/or its attributes modified, + * stores the temporary attributes back to the &rte. + * + * Now, having a "public" version of the route, we + * automatically find any old route defined by the protocol @p * for network @n, replace it by the new one (or removing it if @new is %NULL), * recalculate the optimal route for this destination and finally broadcast - * the change (if any) to all routing protocols. + * the change (if any) to all routing protocols by calling rte_announce(). * * All memory used for attribute lists and other temporary allocations is taken * from a special linear pool @rte_update_pool and freed when rte_update() |