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path: root/bgpd/bgp_mpath.c
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2011-07-20bgpd: We try to skip out of updating the multipath aggregate if there are noJosh Bailey
changes in the multipath set or attributes, but failed to check for just a bestpath change. The result is there is no attribute on the new bestpath and we hit the assert. Added the bestpath check and rearranged the code to only check attributes when there is no bestpath or multipath change, so we only scan the for attribute changes when necessary. * bgpd/bgp_mpath.c * bgp_info_mpath_aggregate_update(): Added check for bestpath change before skipping the aggregate generation. Skip the attribute check if either the multipath set or bestpath has changed.
2011-07-20bgpd: Fix a crash caused by mistakenly dequeueing the bestpath on theJosh Bailey
multipath list. This causes the multipath list to get truncated but the multipath count still reflects what it was before truncation. When we install the route to zebra we fail to fill the nexthop array with the number of nexthop pointers indicated by the multipath count and this leads to a NULL pointer crash in stream_put_in_addr(). Changes: * bgpd/bgp_mpath.c * bgp_info_mpath_update(): If new_mpath is the bestpath we should just move to the next mp_list node. Move dequeue of new_mpath and the code that updates next_mpath to inside the check that new_mpath is not the bestpath.
2011-07-20bgpd: When advertising a multipath route, the attribute set to beJosh Bailey
advertised is based on the bestpath attribute set, but the following attributes are aggregated from the attribute sets of the multipath constituents: - AS_PATH - ORIGIN - COMMUNITIES - EXTENDED COMMUNITIES In addition the route is advertised with the NEXT_HOP set to the router's interface IP address, instead of the NEXT_HOP of the best path. This is to ensure that traffic will go to this router so it can be fanned out via the multipath route. * bgpd/ecommunity.c * ecommunity_uniq_sort(): Make this function externally accessible * bgpd/ecommunity.h * Add external declaration for ecommunity_uniq_sort() * bgpd/bgp_mpath.c * bgp_info_nexthop_cmp(): Replace calls to bgp_attr_extra_get() to avoid unwanted memory allocation * bgp_info_mpath_free(): Free aggregate attribute for multipath * bgp_info_mpath_attr(): Lookup aggregate attribute of a multipath route * bgp_info_mpath_attr_set(): Set aggregate attribute of a multipath route * bgp_info_mpath_aggregate_update(): Update the aggregate attribute of a multipath route * bgpd/bgp_mpath.h * bgp_info_mpath: Add pointer to hold aggregate attribute of a multipath * Add external declarations for new functions * bgpd/bgp_route.c * bgp_announce_check(): Use aggregate attribute when announcing multipath route * bgp_announce_check_rsclient(): Use aggregate attribute when announcing multipath route * bgp_best_selection(): After updating multipath set, update the multipath aggregate attribute
2011-07-20bgpd: For deterministic MED build a multipath set for each peer AS as theJosh Bailey
first stage of the best path calculation. The second stage then selects a winner from each peer AS's best path. In the second stage we clear multipath set of the non-selected best paths via bgp_mp_dmed_deselect(). Since the multipath set is already marked up for the winning path, we don't call bgp_info_mpath_update() after the second stage calculation. * bgpd/bgp_mpath.c * bgp_mp_dmed_deselect(): New function to cleanup the multipath markup if a DMED selected path loses in stage 2 of the best path calculation * bgpd/bgp_mpath.h * Add external declaration of bgp_mp_dmed_deselect() * bgpd/bgp_route.c * bgp_best_selection(): If multipath is enabled, build up the mp_list for the current peer AS, and do the RIB markup the best path from that AS. In the second stage, clear the RIB markup for the DMED selected path if it is not selected as best. Only call bgp_info_mpath_update() in the second stage when not doing deterministic MED.
2011-07-20bgpd: Adds support to mark up the BGP rib table entry with multipathJosh Bailey
information based on the multipath list (mp_list) generated during the best path calculation. Display "multipath" for paths that are multipath and also on bestpath if the route is multipath. Flag a best path with the BGP_INFO_MULTIPATH_CHG if the multipath set has changed since the last update. This can be used to trigger updates to zebra and peers. The multipath markup is a lazily allocated bgp_info_mpath structure that is added to the best path and any multipaths. The mpath structures are linked together with the best path element at the head and the other elements ordered by nexthop and then by peer address. This markup scheme is updated by calling bgp_info_mpath_update() and passing in a new mp_list the the current multipath set. There are additional API's for walking the multipath set, querying the count of multipaths, and for cleaning up the multipath markup information when freeing path information. * bgpd/bgp_mpath.c * bgp_info_mpath_new(): Allocation of new mpath element * bgp_info_mpath_free(): Release memory for mpath element * bgp_info_mpath_get(): Access mpath element of path. Allocate memory on-demand * bgp_info_mpath_enqueue(): Enqueue a path onto the multipath list * bgp_info_mpath_dequeue(): Remove a path from the multipath list * bgp_info_mpath_first(): Return first path on the multipath list * bgp_info_mpath_next(): Return next path on the multipath list * bgp_info_mpath_count(): Return the number of paths on the multipath list * bgp_info_mpath_count_set(): Set the number of paths on the multipath list * bgp_info_mpath_update(): Update multipath markup on bgp route table entry and flag any changes. Emit 'debug bgp event' output on any multipath change. * bgpd/bgp_mpath.h * struct bgp_info_mpath: Information added to a bgp_info path to record multipath information * External declarations for new functions in bgp_mpath.c * bgpd/bgp_route.c * bgp_info_free(): Free mpath memory when freeing path information * bgp_info_reap(): Dequeue path from multipath queue before deleting it * bgp_best_selection(): Calls bgp_info_mpath_update() with latest mp_list to mark-up rib table entry * bgp_vty_out_detail(): Add display of multipath flag for a path. Also display 'multipath' for bestpath if it is a multipath route * bgpd/bgp_route.h * struct bgp_info: Add pointer to bgp_info_mpath information * Add flags to mark a path as multipath (BGP_INFO_MULTIPATH) and to mark bestpath if multipath information has changed (BGP_INFO_MULTIPATH_CHG) * lib/memtypes.c * Add MTYPE_BGP_MPATH_INFO for allocating memory for bgp_info_mpath * tests/bgp_mpath_test.c * Add test case for bgp_info_mpath_update() and supporting functions
2011-07-20bgpd: Adds equal-paths check to path comparison. Paths that areJosh Bailey
equal to the best path are accumulated onto an ordered list (mp_list) if maximum-paths is configured. A future commit will add the multipath markup to the BGP rib table based on the mp_list. Add unit test for the added mp_list functions. Deterministic MED is not supported in this commit, it will be added later. * bgpd/bgp_aspath.c * Make aspath_cmp() an external symbol so it can be used in equivalent paths check * bgpd/bgp_aspath.h * Add extern declaration of aspath_cmp() * bgpd/bgp_mpath.c * bgp_info_nexthop_cmp(): Compares nexthops of two paths * bgp_info_mpath_cmp(): Compare function to order multipaths by nexthop and then by peer address * bgp_mp_list_init(): Initialize a list with the multipath order function * bgp_mp_list_clear(): Clear out the mp_list * bgp_mp_list_add(): Add a multipath to mp_list * bgpd/bgp_mpath.h * External declarations for above added functions in bgp_mpath.c * bgpd/bgp_route.c * bgp_info_cmp(): Add equivalent paths result (paths_eq). If eBGP paths are equal down to IGP metric check, flag as equal if peer AS matches. Similarly for iBGP paths but compare full AS_PATH. * bgp_best_selection(): If multipath is enabled, accumulate equivalent paths in mp_list. Add debug bgp event output to see result (will be filtered later to display only when change occurs) * bgp_process_rsclient(): Pass multipath config to bgp_best_selection() * bgp_process_main(): Pass multipath config to bgp_best_selection() * tests/bgp_mpath_test.c * Add unit test case for bgp_mp_list functions
2011-07-20bgpd: Add new configuration cli for eBGP and iBGP multipath.Josh Bailey
There is support to configure this for each (AFI,SAFI), but currently this configuration is only present for IPv4 unicast: maximum-paths [ibgp] <1-255> no maximum-paths [ibgp] [<1-255>] * bgpd/Makefile.am * Add bgp_mpath.h and bgp_mpath.c to build * bgpd/bgp_mpath.h * New file for bgp multipath declarations * define BGP_DEFAULT_MAXPATHS * bgpd/bgp_mpath.c * bgp_maximum_paths_set(): Configure maximum paths for the given afi, safi and bgp instance * bgp_maximum_paths_unset(): Return maximum paths configuration to the default setting for the given afi, safi and bgp instance * bgpd/bgp_vty.c * Define command strings for above CLI * bgp_config_write_maxpaths(): Outputs configuration for the given afi, safi and bgp instance * Install command elements for IPv4 unicast * bgpd/bgp_zebra.h * bgp_config_write_maxpaths(): External declaration * bgpd/bgpd.c * bgp_create(): Initialize bgp instance to default maximum paths setting * bgp_config_write_family(): Output maximum paths configuration for the given address family * bgp_config_write(): Output maximum paths configuration for IPv4 unicast address family * bgpd/bgpd.h * struct bgp: Add storage for maximum paths configuration for each afi, safi