From 08b1648194e0076220c52aebe27ee1eb5615fd6a Mon Sep 17 00:00:00 2001 From: Neale Ranns Date: Sat, 13 May 2017 05:52:58 -0700 Subject: Fix FIB recursion loops via cover (VPP-842) Change-Id: Ia91c3e8cb27b9e4c1cccefc0a4857dd9995450ab Signed-off-by: Neale Ranns --- src/vnet/fib/fib_entry_src_rr.c | 78 +++++++++++++++++++++++------------------ 1 file changed, 43 insertions(+), 35 deletions(-) (limited to 'src/vnet/fib/fib_entry_src_rr.c') diff --git a/src/vnet/fib/fib_entry_src_rr.c b/src/vnet/fib/fib_entry_src_rr.c index c145aaa2915..d66ef7b1108 100644 --- a/src/vnet/fib/fib_entry_src_rr.c +++ b/src/vnet/fib/fib_entry_src_rr.c @@ -69,6 +69,47 @@ fib_entry_src_rr_init (fib_entry_src_t *src) src->rr.fesr_sibling = FIB_NODE_INDEX_INVALID; } + +/* + * use the path-list of the cover, unless it would form a loop. + * that is unless the cover is via this entry. + * If a loop were to form it would be a 1 level loop (i.e. X via X), + * and there would be 2 locks on the path-list; one since its used + * by the cover, and 1 from here. The first lock will go when the + * cover is removed, the second, and last, when the covered walk + * occurs during the cover's removel - this is not a place where + * we can handle last lock gone. + * In short, don't let the loop form. The usual rules of 'we must + * let it form so we know when it breaks' don't apply here, since + * the loop will break when the cover changes, and this function + * will be called again when that happens. + */ +static void +fib_entry_src_rr_use_covers_pl (fib_entry_src_t *src, + const fib_entry_t *fib_entry, + const fib_entry_t *cover) +{ + fib_node_index_t *entries = NULL; + fib_protocol_t proto; + + proto = fib_entry->fe_prefix.fp_proto; + vec_add1(entries, fib_entry_get_index(fib_entry)); + + if (fib_path_list_recursive_loop_detect(cover->fe_parent, + &entries)) + { + src->fes_pl = fib_path_list_create_special( + proto, + FIB_PATH_LIST_FLAG_DROP, + drop_dpo_get(fib_proto_to_dpo(proto))); + } + else + { + src->fes_pl = cover->fe_parent; + } + vec_free(entries); +} + /* * Source activation. Called when the source is the new best source on the entry */ @@ -112,40 +153,7 @@ fib_entry_src_rr_activate (fib_entry_src_t *src, } else { - /* - * use the path-list of the cover, unless it would form a loop. - * that is unless the cover is via this entry. - * If a loop were to form it would be a 1 level loop (i.e. X via X), - * and there would be 2 locks on the path-list; one since its used - * by the cover, and 1 from here. The first lock will go when the - * cover is removed, the second, and last, when the covered walk - * occurs during the cover's removel - this is not a place where - * we can handle last lock gone. - * In short, don't let the loop form. The usual rules of 'we must - * let it form so we know when it breaks' don't apply here, since - * the loop will break when the cover changes, and this function - * will be called again when that happens. - */ - fib_node_index_t *entries = NULL; - fib_protocol_t proto; - - proto = fib_entry->fe_prefix.fp_proto; - vec_add1(entries, fib_entry_get_index(fib_entry)); - - if (fib_path_list_recursive_loop_detect(cover->fe_parent, - &entries)) - { - src->fes_pl = fib_path_list_create_special( - proto, - FIB_PATH_LIST_FLAG_DROP, - drop_dpo_get(fib_proto_to_dpo(proto))); - } - else - { - src->fes_pl = cover->fe_parent; - } - vec_free(entries); - + fib_entry_src_rr_use_covers_pl(src, fib_entry, cover); } fib_path_list_lock(src->fes_pl); @@ -256,7 +264,7 @@ fib_entry_src_rr_cover_update (fib_entry_src_t *src, } else { - src->fes_pl = cover->fe_parent; + fib_entry_src_rr_use_covers_pl(src, fib_entry, cover); } fib_path_list_lock(src->fes_pl); fib_path_list_unlock(old_path_list); -- cgit 1.2.3-korg