/* * Copyright (c) 2016 Cisco and/or its affiliates. * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. * You may obtain a copy of the License at: * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */ #include <vlib/vlib.h> #include <vnet/ip/format.h> #include <vnet/ip/lookup.h> #include <vnet/adj/adj.h> #include <vnet/dpo/drop_dpo.h> #include "fib_entry_src.h" #include "fib_entry_cover.h" #include "fib_entry.h" #include "fib_table.h" /* * fib_entry_src_rr_resolve_via_connected * * Resolve via a connected cover. */ static void fib_entry_src_rr_resolve_via_connected (fib_entry_src_t *src, const fib_entry_t *fib_entry, const fib_entry_t *cover) { const fib_route_path_t path = { .frp_proto = fib_entry->fe_prefix.fp_proto, .frp_addr = fib_entry->fe_prefix.fp_addr, .frp_sw_if_index = fib_entry_get_resolving_interface( fib_entry_get_index(cover)), .frp_fib_index = ~0, .frp_weight = 1, }; fib_route_path_t *paths = NULL; vec_add1(paths, path); /* * since the cover is connected, the address this entry corresponds * to is a peer (ARP-able for) on the interface to which the cover is * connected. The fact we resolve via the cover, just means this RR * source is the first SRC to use said peer. The ARP source will be along * shortly to over-rule this RR source. */ src->fes_pl = fib_path_list_create(FIB_PATH_LIST_FLAG_NONE, paths); src->fes_entry_flags = fib_entry_get_flags(fib_entry_get_index(cover)); vec_free(paths); } /** * Source initialisation Function */ static void fib_entry_src_rr_init (fib_entry_src_t *src) { src->rr.fesr_cover = FIB_NODE_INDEX_INVALID; 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 */ static int fib_entry_src_rr_activate (fib_entry_src_t *src, const fib_entry_t *fib_entry) { fib_entry_t *cover; /* * find the covering prefix. become a dependent thereof. * for IP there should always be a cover, though it may be the default route. * For MPLS there is never a cover. */ if (FIB_PROTOCOL_MPLS == fib_entry->fe_prefix.fp_proto) { src->fes_pl = fib_path_list_create_special(FIB_PROTOCOL_MPLS, FIB_PATH_LIST_FLAG_DROP, NULL); fib_path_list_lock(src->fes_pl); return (!0); } src->rr.fesr_cover = fib_table_get_less_specific(fib_entry->fe_fib_index, &fib_entry->fe_prefix); ASSERT(FIB_NODE_INDEX_INVALID != src->rr.fesr_cover); cover = fib_entry_get(src->rr.fesr_cover); src->rr.fesr_sibling = fib_entry_cover_track(cover, fib_entry_get_index(fib_entry)); /* * if the cover is attached then install an attached-host path * (like an adj-fib). Otherwise inherit the forwarding from the cover */ if (FIB_ENTRY_FLAG_ATTACHED & fib_entry_get_flags_i(cover)) { fib_entry_src_rr_resolve_via_connected(src, fib_entry, cover); } else { fib_entry_src_rr_use_covers_pl(src, fib_entry, cover); } fib_path_list_lock(src->fes_pl); /* * return go for install */ return (!0); } /** * Source Deactivate. * Called when the source is no longer best source on the entry */ static void fib_entry_src_rr_deactivate (fib_entry_src_t *src, const fib_entry_t *fib_entry) { fib_entry_t *cover; /* * remove the depednecy on the covering entry */ if (FIB_NODE_INDEX_INVALID != src->rr.fesr_cover) { cover = fib_entry_get(src->rr.fesr_cover); fib_entry_cover_untrack(cover, src->rr.fesr_sibling); src->rr.fesr_cover = FIB_NODE_INDEX_INVALID; } fib_path_list_unlock(src->fes_pl); src->fes_pl = FIB_NODE_INDEX_INVALID; src->fes_entry_flags = FIB_ENTRY_FLAG_NONE; } static fib_entry_src_cover_res_t fib_entry_src_rr_cover_change (fib_entry_src_t *src, const fib_entry_t *fib_entry) { fib_entry_src_cover_res_t res = { .install = !0, .bw_reason = FIB_NODE_BW_REASON_FLAG_NONE, }; if (FIB_NODE_INDEX_INVALID == src->rr.fesr_cover) { /* * the source may be added, but it is not active * if it is not tracking the cover. */ return (res); } /* * this function is called when this entry's cover has a more specific * entry inserted benaeth it. That does not necessarily mean that this * entry is covered by the new prefix. check that */ if (src->rr.fesr_cover != fib_table_get_less_specific(fib_entry->fe_fib_index, &fib_entry->fe_prefix)) { fib_entry_src_rr_deactivate(src, fib_entry); fib_entry_src_rr_activate(src, fib_entry); /* * dependent children need to re-resolve to the new forwarding info */ res.bw_reason = FIB_NODE_BW_REASON_FLAG_EVALUATE; } return (res); } /* * fib_entry_src_rr_cover_update * * This entry's cover has updated its forwarding info. This entry * will need to re-inheret. */ static fib_entry_src_cover_res_t fib_entry_src_rr_cover_update (fib_entry_src_t *src, const fib_entry_t *fib_entry) { fib_entry_src_cover_res_t res = { .install = !0, .bw_reason = FIB_NODE_BW_REASON_FLAG_NONE, }; fib_node_index_t old_path_list; fib_entry_t *cover; if (FIB_NODE_INDEX_INVALID == src->rr.fesr_cover) { /* * the source may be added, but it is not active * if it is not tracking the cover. */ return (res); } cover = fib_entry_get(src->rr.fesr_cover); old_path_list = src->fes_pl; /* * if the ocver is attached then install an attached-host path * (like an adj-fib). Otherwise inherit the forwarding from the cover */ if (FIB_ENTRY_FLAG_ATTACHED & fib_entry_get_flags_i(cover)) { fib_entry_src_rr_resolve_via_connected(src, fib_entry, cover); } else { 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); /* * dependent children need to re-resolve to the new forwarding info */ res.bw_reason = FIB_NODE_BW_REASON_FLAG_EVALUATE; return (res); } static u8* fib_entry_src_rr_format (fib_entry_src_t *src, u8* s) { return (format(s, "cover:%d", src->rr.fesr_cover)); } const static fib_entry_src_vft_t rr_src_vft = { .fesv_init = fib_entry_src_rr_init, .fesv_activate = fib_entry_src_rr_activate, .fesv_deactivate = fib_entry_src_rr_deactivate, .fesv_cover_change = fib_entry_src_rr_cover_change, .fesv_cover_update = fib_entry_src_rr_cover_update, .fesv_format = fib_entry_src_rr_format, }; void fib_entry_src_rr_register (void) { fib_entry_src_register(FIB_SOURCE_RR, &rr_src_vft); fib_entry_src_register(FIB_SOURCE_URPF_EXEMPT, &rr_src_vft); }