/* * BIRD Internet Routing Daemon -- Route aggregation * * (c) 2023--2023 Igor Putovny * (c) 2023 CZ.NIC, z.s.p.o. * * Can be freely distributed and used under the terms of the GNU GPL. */ /** * DOC: Route aggregation * * This is an implementation of route aggregation functionality. * It enables user to specify a set of route attributes in the configuarion file * and then, for a given destination (net), aggregate routes with the same * values of these attributes into a single multi-path route. * * Structure &channel contains pointer to aggregation list which is represented * by &aggr_list_linearized. In rt_notify_aggregated(), attributes from this * list are evaluated for every route of a given net and results are stored * in &rte_val_list which contains pointer to this route and array of &f_val. * Array of pointers to &rte_val_list entries is sorted using * sort_rte_val_list(). For comparison of &f_val structures, val_compare() * is used. Comparator function is written so that sorting is stable. If all * attributes have the same values, routes are compared by their global IDs. * * After sorting, &rte_val_list entries containing equivalent routes will be * adjacent to each other. Function process_rte_list() iterates through these * entries to identify sequences of equivalent routes. New route will be * created for each such sequence, even if only from a single route. * Only attributes from the aggreagation list will be set for the new route. * New &rta is created and prepare_rta() is used to copy static and dynamic * attributes to new &rta from &rta of the original route. New route is created * by create_merged_rte() from new &rta and exported to the routing table. */ #undef LOCAL_DEBUG #ifndef _GNU_SOURCE #define _GNU_SOURCE #endif #include "nest/bird.h" #include "nest/iface.h" #include "filter/filter.h" #include "aggregator.h" #include /* #include "nest/route.h" #include "nest/iface.h" #include "lib/resource.h" #include "lib/event.h" #include "lib/timer.h" #include "lib/string.h" #include "conf/conf.h" #include "filter/filter.h" #include "filter/data.h" #include "lib/hash.h" #include "lib/string.h" #include "lib/alloca.h" #include "lib/flowspec.h" */ /* Context of &f_val comparison. */ struct cmp_ctx { const struct aggregator_proto *p; const struct network *net; const int val_count; u32 failed:1; }; extern linpool *rte_update_pool; /* * Set static attribute in @rta from static attribute in @old according to @sa. */ static void rta_set_static_attr(struct rta *rta, const struct rta *old, struct f_static_attr sa) { switch (sa.sa_code) { case SA_NET: break; case SA_FROM: rta->from = old->from; break; case SA_GW: rta->dest = RTD_UNICAST; rta->nh.gw = old->nh.gw; rta->nh.iface = old->nh.iface; rta->nh.next = NULL; rta->hostentry = NULL; rta->nh.labels = 0; break; case SA_SCOPE: rta->scope = old->scope; break; case SA_DEST: rta->dest = old->dest; rta->nh.gw = IPA_NONE; rta->nh.iface = NULL; rta->nh.next = NULL; rta->hostentry = NULL; rta->nh.labels = 0; break; case SA_IFNAME: rta->dest = RTD_UNICAST; rta->nh.gw = IPA_NONE; rta->nh.iface = old->nh.iface; rta->nh.next = NULL; rta->hostentry = NULL; rta->nh.labels = 0; break; case SA_GW_MPLS: rta->nh.labels = old->nh.labels; memcpy(&rta->nh.label, &old->nh.label, sizeof(u32) * old->nh.labels); break; case SA_WEIGHT: rta->nh.weight = old->nh.weight; break; case SA_PREF: rta->pref = old->pref; break; default: bug("Invalid static attribute access (%u/%u)", sa.f_type, sa.sa_code); } } /* * Compare list of &f_val entries. * @count: number of &f_val entries */ static int same_val_list(const struct f_val *v1, const struct f_val *v2, uint len) { for (uint i = 0; i < len; i++) if (!val_same(&v1[i], &v2[i])) return 0; return 1; } /* * Create and export new merged route. * @old: first route in a sequence of equivalent routes that are to be merged * @rte_val: first element in a sequence of equivalent rte_val_list entries * @length: number of equivalent routes that are to be merged (at least 1) * @ail: aggregation list */ static void aggregator_bucket_update(struct aggregator_proto *p, struct aggregator_bucket *bucket, struct network *net) { /* Empty bucket */ if (!bucket->rte) { rte_update2(p->dst, net->n.addr, NULL, bucket->last_src); bucket->last_src = NULL; return; } /* Allocate RTA and EA list */ struct rta *rta = allocz(rta_size(bucket->rte->attrs)); rta->dest = RTD_UNREACHABLE; rta->source = RTS_AGGREGATED; rta->scope = SCOPE_UNIVERSE; struct ea_list *eal = allocz(sizeof(struct ea_list) + sizeof(struct eattr) * p->aggr_on_da_count); eal->next = NULL; eal->count = 0; rta->eattrs = eal; /* Seed the attributes from aggregator rule */ for (uint i = 0; i < p->aggr_on_count; i++) { if (p->aggr_on[i].type == AGGR_ITEM_DYNAMIC_ATTR) { u32 ea_code = p->aggr_on[i].da.ea_code; const struct eattr *e = ea_find(bucket->rte->attrs->eattrs, ea_code); if (e) eal->attrs[eal->count++] = *e; } else if (p->aggr_on[i].type == AGGR_ITEM_STATIC_ATTR) rta_set_static_attr(rta, bucket->rte->attrs, p->aggr_on[i].sa); } struct rte *new = rte_get_temp(rta, bucket->rte->src); new->net = net; /* log("=============== CREATE MERGED ROUTE ==============="); log("New route created: id = %d, protocol: %s", new->src->global_id, new->src->proto->name); log("==================================================="); */ /* merge filter needs one argument called "routes" */ struct f_val val = { .type = T_ROUTES_BLOCK, .val.rte = bucket->rte, }; /* Actually run the filter */ enum filter_return fret = f_eval_rte(p->merge_by, &new, rte_update_pool, 1, &val, 0); /* Src must be stored now, rte_update2() may return new */ struct rte_src *new_src = new ? new->src : NULL; /* Finally import the route */ switch (fret) { /* Pass the route to the protocol */ case F_ACCEPT: rte_update2(p->dst, net->n.addr, new, bucket->last_src ?: new->src); break; /* Something bad happened */ default: ASSERT_DIE(fret == F_ERROR); /* fall through */ /* We actually don't want this route */ case F_REJECT: if (bucket->last_src) rte_update2(p->dst, net->n.addr, NULL, bucket->last_src); break; } /* Switch source lock for bucket->last_src */ if (bucket->last_src != new_src) { if (new_src) rt_lock_source(new_src); if (bucket->last_src) rt_unlock_source(bucket->last_src); bucket->last_src = new_src; } } /* * Reload all the buckets on reconfiguration if merge filter has changed. * TODO: make this splitted */ static void aggregator_reload_buckets(void *data) { struct aggregator_proto *p = data; HASH_WALK(p->buckets, next_hash, b) if (b->rte) aggregator_bucket_update(p, b, b->rte->net); HASH_WALK_END; } /* * Evaluate static attribute of @rt1 according to @sa * and store result in @pos. */ static void eval_static_attr(const struct rte *rt1, struct f_static_attr sa, struct f_val *pos) { const struct rta *rta = rt1->attrs; #define RESULT(_type, value, result) \ do { \ pos->type = _type; \ pos->val.value = result; \ } while (0) switch (sa.sa_code) { case SA_NET: RESULT(sa.f_type, net, rt1->net->n.addr); break; case SA_FROM: RESULT(sa.f_type, ip, rta->from); break; case SA_GW: RESULT(sa.f_type, ip, rta->nh.gw); break; case SA_PROTO: RESULT(sa.f_type, s, rt1->src->proto->name); break; case SA_SOURCE: RESULT(sa.f_type, i, rta->source); break; case SA_SCOPE: RESULT(sa.f_type, i, rta->scope); break; case SA_DEST: RESULT(sa.f_type, i, rta->dest); break; case SA_IFNAME: RESULT(sa.f_type, s, rta->nh.iface ? rta->nh.iface->name : ""); break; case SA_IFINDEX: RESULT(sa.f_type, i, rta->nh.iface ? rta->nh.iface->index : 0); break; case SA_WEIGHT: RESULT(sa.f_type, i, rta->nh.weight + 1); break; case SA_PREF: RESULT(sa.f_type, i, rta->pref); break; case SA_GW_MPLS: RESULT(sa.f_type, i, rta->nh.labels ? rta->nh.label[0] : MPLS_NULL); break; default: bug("Invalid static attribute access (%u/%u)", sa.f_type, sa.sa_code); } #undef RESULT } /* * Evaluate dynamic attribute of @rt1 according to @da * and store result in @pos. */ static void eval_dynamic_attr(const struct rte *rt1, struct f_dynamic_attr da, struct f_val *pos) { const struct rta *rta = rt1->attrs; const struct eattr *e = ea_find(rta->eattrs, da.ea_code); #define RESULT(_type, value, result) \ do { \ pos->type = _type; \ pos->val.value = result; \ } while (0) #define RESULT_VOID \ do { \ pos->type = T_VOID; \ } while (0) if (!e) { /* A special case: undefined as_path looks like empty as_path */ if (da.type == EAF_TYPE_AS_PATH) { RESULT(T_PATH, ad, &null_adata); return; } /* The same special case for int_set */ if (da.type == EAF_TYPE_INT_SET) { RESULT(T_CLIST, ad, &null_adata); return; } /* The same special case for ec_set */ if (da.type == EAF_TYPE_EC_SET) { RESULT(T_ECLIST, ad, &null_adata); return; } /* The same special case for lc_set */ if (da.type == EAF_TYPE_LC_SET) { RESULT(T_LCLIST, ad, &null_adata); return; } /* Undefined value */ RESULT_VOID; return; } switch (e->type & EAF_TYPE_MASK) { case EAF_TYPE_INT: RESULT(da.f_type, i, e->u.data); break; case EAF_TYPE_ROUTER_ID: RESULT(T_QUAD, i, e->u.data); break; case EAF_TYPE_OPAQUE: RESULT(T_ENUM_EMPTY, i, 0); break; case EAF_TYPE_IP_ADDRESS: RESULT(T_IP, ip, *((ip_addr *) e->u.ptr->data)); break; case EAF_TYPE_AS_PATH: RESULT(T_PATH, ad, e->u.ptr); break; case EAF_TYPE_BITFIELD: RESULT(T_BOOL, i, !!(e->u.data & (1u << da.bit))); break; case EAF_TYPE_INT_SET: RESULT(T_CLIST, ad, e->u.ptr); break; case EAF_TYPE_EC_SET: RESULT(T_ECLIST, ad, e->u.ptr); break; case EAF_TYPE_LC_SET: RESULT(T_LCLIST, ad, e->u.ptr); break; default: bug("Unknown dynamic attribute type"); } #undef RESULT #undef RESULT_VOID } static inline u32 aggr_route_hash(const rte *e) { struct { net *net; struct rte_src *src; } obj = { .net = e->net, .src = e->src, }; return mem_hash(&obj, sizeof obj); } #define AGGR_RTE_KEY(n) (&(n)->rte) #define AGGR_RTE_NEXT(n) ((n)->next_hash) #define AGGR_RTE_EQ(a,b) (((a)->src == (b)->src) && ((a)->net == (b)->net)) #define AGGR_RTE_FN(_n) aggr_route_hash(_n) #define AGGR_RTE_ORDER 4 /* Initial */ #define AGGR_RTE_REHASH aggr_rte_rehash #define AGGR_RTE_PARAMS /8, *2, 2, 2, 4, 24 HASH_DEFINE_REHASH_FN(AGGR_RTE, struct aggregator_route); #define AGGR_BUCK_KEY(n) (n) #define AGGR_BUCK_NEXT(n) ((n)->next_hash) #define AGGR_BUCK_EQ(a,b) (((a)->hash == (b)->hash) && (same_val_list((a)->aggr_data, (b)->aggr_data, p->aggr_on_count))) #define AGGR_BUCK_FN(n) ((n)->hash) #define AGGR_BUCK_ORDER 4 /* Initial */ #define AGGR_BUCK_REHASH aggr_buck_rehash #define AGGR_BUCK_PARAMS /8, *2, 2, 2, 4, 24 HASH_DEFINE_REHASH_FN(AGGR_BUCK, struct aggregator_bucket); #define AGGR_DATA_MEMSIZE (sizeof(struct f_val) * p->aggr_on_count) static void aggregator_rt_notify(struct proto *P, struct channel *src_ch, net *net, rte *new, rte *old) { struct aggregator_proto *p = SKIP_BACK(struct aggregator_proto, p, P); ASSERT_DIE(src_ch == p->src); struct aggregator_bucket *new_bucket = NULL, *old_bucket = NULL; struct aggregator_route *old_route = NULL; /* Find the objects for the old route */ if (old) old_route = HASH_FIND(p->routes, AGGR_RTE, old); if (old_route) old_bucket = old_route->bucket; /* Find the bucket for the new route */ if (new) { /* Routes are identical, do nothing */ if (old_route && rte_same(&old_route->rte, new)) return; /* Evaluate route attributes. */ struct aggregator_bucket *tmp_bucket = sl_allocz(p->bucket_slab); for (uint val_idx = 0; val_idx < p->aggr_on_count; val_idx++) { int type = p->aggr_on[val_idx].type; switch (type) { case AGGR_ITEM_TERM: { const struct f_line *line = p->aggr_on[val_idx].line; struct rte *rt1 = new; enum filter_return fret = f_eval_rte(line, &new, rte_update_pool, 0, NULL, &tmp_bucket->aggr_data[val_idx]); if (rt1 != new) { rte_free(rt1); log(L_WARN "Aggregator rule modifies the route, reverting"); } if (fret > F_RETURN) log(L_WARN "%s.%s: Wrong number of items left on stack after evaluation of aggregation list", rt1->src->proto->name, rt1->sender); break; } case AGGR_ITEM_STATIC_ATTR: { struct f_val *pos = &tmp_bucket->aggr_data[val_idx]; eval_static_attr(new, p->aggr_on[val_idx].sa, pos); break; } case AGGR_ITEM_DYNAMIC_ATTR: { struct f_val *pos = &tmp_bucket->aggr_data[val_idx]; eval_dynamic_attr(new, p->aggr_on[val_idx].da, pos); break; } default: break; } } /* Compute the hash */ tmp_bucket->hash = mem_hash(tmp_bucket->aggr_data, AGGR_DATA_MEMSIZE); /* Find the existing bucket */ if (new_bucket = HASH_FIND(p->buckets, AGGR_BUCK, tmp_bucket)) sl_free(tmp_bucket); else { new_bucket = tmp_bucket; HASH_INSERT2(p->buckets, AGGR_BUCK, p->p.pool, new_bucket); } /* Store the route attributes */ if (rta_is_cached(new->attrs)) rta_clone(new->attrs); else new->attrs = rta_lookup(new->attrs); /* Insert the new route into the bucket */ struct aggregator_route *arte = sl_alloc(p->route_slab); *arte = (struct aggregator_route) { .bucket = new_bucket, .rte = *new, }; arte->rte.next = new_bucket->rte, new_bucket->rte = &arte->rte; new_bucket->count++; HASH_INSERT2(p->routes, AGGR_RTE, p->p.pool, arte); } /* Remove the old route from its bucket */ if (old_bucket) { for (struct rte **k = &old_bucket->rte; *k; k = &(*k)->next) if (*k == &old_route->rte) { *k = (*k)->next; break; } old_bucket->count--; HASH_REMOVE2(p->routes, AGGR_RTE, p->p.pool, old_route); rta_free(old_route->rte.attrs); sl_free(old_route); } /* Announce changes */ if (old_bucket) aggregator_bucket_update(p, old_bucket, net); if (new_bucket && (new_bucket != old_bucket)) aggregator_bucket_update(p, new_bucket, net); /* Cleanup the old bucket if empty */ if (old_bucket && (!old_bucket->rte || !old_bucket->count)) { ASSERT_DIE(!old_bucket->rte && !old_bucket->count); HASH_REMOVE2(p->buckets, AGGR_BUCK, p->p.pool, old_bucket); sl_free(old_bucket); } } static int aggregator_preexport(struct channel *C, struct rte *new) { struct aggregator_proto *p = SKIP_BACK(struct aggregator_proto, p, C->proto); /* Reject our own routes */ if (new->sender == p->dst) return -1; /* Disallow aggregating already aggregated routes */ if (new->attrs->source == RTS_AGGREGATED) { log(L_ERR "Multiple aggregations of the same route not supported in BIRD 2."); return -1; } return 0; } static void aggregator_postconfig(struct proto_config *CF) { struct aggregator_config *cf = SKIP_BACK(struct aggregator_config, c, CF); if (!cf->dst->table) cf_error("Source table not specified"); if (!cf->src->table) cf_error("Destination table not specified"); if (cf->dst->table->addr_type != cf->src->table->addr_type) cf_error("Both tables must be of the same type"); cf->dst->in_filter = cf->src->in_filter; cf->src->in_filter = FILTER_REJECT; cf->dst->out_filter = FILTER_REJECT; cf->dst->debug = cf->src->debug; } static struct proto * aggregator_init(struct proto_config *CF) { struct proto *P = proto_new(CF); struct aggregator_proto *p = SKIP_BACK(struct aggregator_proto, p, P); struct aggregator_config *cf = SKIP_BACK(struct aggregator_config, c, CF); proto_configure_channel(P, &p->src, cf->src); proto_configure_channel(P, &p->dst, cf->dst); p->aggr_on_count = cf->aggr_on_count; p->aggr_on_da_count = cf->aggr_on_da_count; p->aggr_on = cf->aggr_on; p->merge_by = cf->merge_by; P->rt_notify = aggregator_rt_notify; P->preexport = aggregator_preexport; return P; } static int aggregator_start(struct proto *P) { struct aggregator_proto *p = SKIP_BACK(struct aggregator_proto, p, P); p->bucket_slab = sl_new(P->pool, sizeof(struct aggregator_bucket) + AGGR_DATA_MEMSIZE); HASH_INIT(p->buckets, P->pool, AGGR_BUCK_ORDER); p->route_slab = sl_new(P->pool, sizeof(struct aggregator_route)); HASH_INIT(p->routes, P->pool, AGGR_RTE_ORDER); p->reload_buckets = (event) { .hook = aggregator_reload_buckets, .data = p, }; return PS_UP; } static int aggregator_shutdown(struct proto *P) { struct aggregator_proto *p = SKIP_BACK(struct aggregator_proto, p, P); HASH_WALK_DELSAFE(p->buckets, next_hash, b) { while (b->rte) { struct aggregator_route *arte = SKIP_BACK(struct aggregator_route, rte, b->rte); b->rte = arte->rte.next; b->count--; HASH_REMOVE(p->routes, AGGR_RTE, arte); rta_free(arte->rte.attrs); sl_free(arte); } ASSERT_DIE(b->count == 0); HASH_REMOVE(p->buckets, AGGR_BUCK, b); sl_free(b); } HASH_WALK_END; return PS_DOWN; } static int aggregator_reconfigure(struct proto *P, struct proto_config *CF) { struct aggregator_proto *p = SKIP_BACK(struct aggregator_proto, p, P); struct aggregator_config *cf = SKIP_BACK(struct aggregator_config, c, CF); TRACE(D_EVENTS, "Reconfiguring"); /* Compare numeric values (shortcut) */ if (cf->aggr_on_count != p->aggr_on_count) return 0; if (cf->aggr_on_da_count != p->aggr_on_da_count) return 0; /* Compare aggregator rule */ for (uint i = 0; i < p->aggr_on_count; i++) switch (cf->aggr_on[i].type) { case AGGR_ITEM_TERM: if (!f_same(cf->aggr_on[i].line, p->aggr_on[i].line)) return 0; break; case AGGR_ITEM_STATIC_ATTR: if (memcmp(&cf->aggr_on[i].sa, &p->aggr_on[i].sa, sizeof(struct f_static_attr)) != 0) return 0; break; case AGGR_ITEM_DYNAMIC_ATTR: if (memcmp(&cf->aggr_on[i].da, &p->aggr_on[i].da, sizeof(struct f_dynamic_attr)) != 0) return 0; break; default: bug("Broken aggregator rule"); } /* Compare merge filter */ if (!f_same(cf->merge_by, p->merge_by)) ev_schedule(&p->reload_buckets); p->aggr_on = cf->aggr_on; p->merge_by = cf->merge_by; return 1; } struct protocol proto_aggregator = { .name = "Aggregator", .template = "aggregator%d", .class = PROTOCOL_AGGREGATOR, .preference = 1, .channel_mask = NB_ANY, .proto_size = sizeof(struct aggregator_proto), .config_size = sizeof(struct aggregator_config), .postconfig = aggregator_postconfig, .init = aggregator_init, .start = aggregator_start, .shutdown = aggregator_shutdown, .reconfigure = aggregator_reconfigure, }; void aggregator_build(void) { proto_build(&proto_aggregator); }