Commit c5ff44a7 authored by Ondrej Zajicek's avatar Ondrej Zajicek
Browse files

KRT: Fixes learning of preferred kernel routes. 

When a new route was imported from kernel and chosen as preferred, then
the old best route was propagated as a withdraw to the kernel protocol.
Under some circumstances such withdraw propagated to the BSD kernel could
remove the new alien route and thus reverting the import.
parent 90097f4f

sysdep/cf/README

+1 −0
Original line number Diff line number Diff line
@@ -5,6 +5,7 @@ CONFIG_AUTO_ROUTES Device routes are added automagically by the kernel 
CONFIG_SELF_CONSCIOUS	We're able to recognize whether route was installed by us

CONFIG_MULTIPLE_TABLES	The kernel supports multiple routing tables

CONFIG_ALL_TABLES_AT_ONCE	Kernel scanner wants to process all tables at once

CONFIG_SINGLE_ROUTE	There is only one route per network



CONFIG_MC_PROPER_SRC	Multicast packets have source address according to socket saddr field

CONFIG_SKIP_MC_BIND	Don't call bind on multicast socket (def for *BSD)

sysdep/cf/bsd-v6.h

+1 −0
Original line number Diff line number Diff line
@@ -11,6 +11,7 @@ 
#define CONFIG_AUTO_ROUTES

#define CONFIG_SELF_CONSCIOUS

#define CONFIG_MULTIPLE_TABLES

#define CONFIG_SINGLE_ROUTE



#define CONFIG_SKIP_MC_BIND

#define CONFIG_NO_IFACE_BIND

sysdep/cf/bsd.h

+1 −0
Original line number Diff line number Diff line
@@ -9,6 +9,7 @@ 
#define CONFIG_AUTO_ROUTES

#define CONFIG_SELF_CONSCIOUS

#define CONFIG_MULTIPLE_TABLES

#define CONFIG_SINGLE_ROUTE



#define CONFIG_SKIP_MC_BIND

#define CONFIG_NO_IFACE_BIND

sysdep/unix/krt.c

+14 −0
Original line number Diff line number Diff line
@@ -961,7 +961,21 @@ krt_import_control(struct proto *P, rte **new, ea_list **attrs, struct linpool * 
  rte *e = *new;



  if (e->attrs->src->proto == P)

  {

#ifdef CONFIG_SINGLE_ROUTE

    /*

     * Implicit withdraw - when the imported kernel route becomes the best one,

     * we know that the previous one exported to the kernel was already removed,

     * but if we processed the update as usual, we would send withdraw to the

     * kernel, which would remove the new imported route instead.

     *

     * We will remove KRT_INSTALLED flag, which stops such withdraw to be

     * processed in krt_rt_notify() and krt_replace_rte().

     */

    e->net->n.flags &= ~KRF_INSTALLED;

#endif

    return -1;

  }



  if (!KRT_CF->devroutes &&

      (e->attrs->dest == RTD_DEVICE) &&

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