Basic route aggregation

Add a new protocol offering route aggregation.

User can specify list of route attributes in the configuration file and
run route aggregation on the export side of the pipe protocol. Routes are
sorted and for every group of equivalent routes new route is created and
exported to the routing table. It is also possible to specify filter
which will run for every route before aggregation.

Furthermore, it will be possible to set attributes of new routes
according to attributes of the aggregated routes.

This is a work in progress.

Original work by Igor Putovny, subsequent cleanups and finalization by
Maria Matejka.

1 files changed, 134 insertions, 0 deletions

diff --git a/proto/aggregator/config.Y b/proto/aggregator/config.Y
new file mode 100644
index 00000000..44b7752f
--- /dev/null
+++ b/proto/aggregator/config.Y
@@ -0,0 +1,134 @@
+/*
+ *	BIRD -- Aggregator configuration
+ *
+ *	(c) 2023       Igor Putovny <igor.putovny@nic.cz>
+ *	(c) 2023       Maria Matejka <mq@ucw.cz>
+ *	(c) 2023       CZ.NIC z.s.p.o.
+ *
+ *	Can be freely distributed and used under the terms of the GNU GPL.
+ */
+
+CF_HDR
+
+#include "proto/aggregator/aggregator.h"
+
+CF_DEFINES
+
+#define AGGREGATOR_CFG ((struct aggregator_config *) this_proto)
+#define AGGR_ITEM_ALLOC ((struct aggr_item_node *) cfg_allocz(sizeof(struct aggr_item_node)))
+
+
+CF_DECLS
+
+CF_KEYWORDS(AGGREGATOR, AGGREGATE, ON, MERGE, BY)
+
+%type <ai> aggr_item aggr_list
+
+CF_GRAMMAR
+
+proto: aggregator_proto ;
+
+aggregator_proto_start: proto_start AGGREGATOR
+{
+  this_proto = proto_config_new(&proto_aggregator, $1);
+  this_channel = AGGREGATOR_CFG->src = channel_config_new(NULL, "source", 0, this_proto);
+  AGGREGATOR_CFG->dst = channel_config_new(NULL, "destination", 0, this_proto);
+
+  AGGREGATOR_CFG->src->ra_mode = AGGREGATOR_CFG->dst->ra_mode = RA_ANY;
+};
+
+aggregator_proto_item:
+   proto_item
+ | channel_item_
+ | PEER TABLE rtable { AGGREGATOR_CFG->dst->table = $3; }
+ | AGGREGATE ON aggr_list {
+    if (AGGREGATOR_CFG->aggr_on)
+      cf_error("Only one aggregate on clause allowed");
+
+    _Bool net_present = 0;
+    int count = 0;
+
+    for (const struct aggr_item_node *item = $3; item; item = item->next) {
+//      log(L_WARN "type %d sacode %d", item->i.type, item->i.sa.sa_code);
+      if (item->i.type == AGGR_ITEM_STATIC_ATTR && item->i.sa.sa_code == SA_NET)
+	net_present = 1;
+
+      count++;
+    }
+
+   if (!net_present)
+     cf_error("'NET' must be present");
+
+   AGGREGATOR_CFG->aggr_on = cfg_alloc(sizeof(struct aggr_item) * count);
+
+   int pos = 0;
+   for (const struct aggr_item_node *item = $3; item; item = item->next) {
+     if (item->i.type == AGGR_ITEM_DYNAMIC_ATTR)
+       AGGREGATOR_CFG->aggr_on_da_count++;
+
+     AGGREGATOR_CFG->aggr_on[pos++] = item->i;
+   }
+
+   AGGREGATOR_CFG->aggr_on_count = pos;
+ }
+ | MERGE BY {
+   cf_push_block_scope(new_config);
+   cf_create_symbol(new_config, "routes", SYM_VARIABLE | T_ROUTES_BLOCK, offset, f_new_var(sym_->scope));
+ } function_body {
+   cf_pop_block_scope(new_config);
+   $4->args++;
+   AGGREGATOR_CFG->merge_by = $4;
+ }
+;
+
+aggregator_proto_opts: /* empty */ | aggregator_proto_opts aggregator_proto_item ';' ;
+aggregator_proto: aggregator_proto_start proto_name '{' aggregator_proto_opts '}' ;
+
+
+aggr_list:
+   aggr_item
+ | aggr_list ',' aggr_item {
+       if ($3 == NULL) {
+         $$ = $1;
+       } else {
+         $$ = $3;
+         $$->next = $1;
+       }
+   }
+ ;
+
+aggr_item:
+   '(' term ')' {
+       $$ = AGGR_ITEM_ALLOC;
+       $$->i.type = AGGR_ITEM_TERM;
+       $$->i.line = f_linearize($2, 1);
+    }
+  | CF_SYM_KNOWN {
+      switch ($1->class) {
+        case SYM_ATTRIBUTE:
+          $$ = AGGR_ITEM_ALLOC;
+          $$->i.type = AGGR_ITEM_DYNAMIC_ATTR;
+          $$->i.da = *$1->attribute;
+          break;
+        case SYM_CONSTANT_RANGE:
+          $$ = NULL;
+          break;
+        default:
+          cf_error("Can't aggregate on symbol type %s.", cf_symbol_class_name($1));
+      }
+    }
+  | dynamic_attr {
+      $$ = AGGR_ITEM_ALLOC;
+      $$->i.type = AGGR_ITEM_DYNAMIC_ATTR;
+      $$->i.da = $1;
+    }
+  | static_attr {
+      $$ = AGGR_ITEM_ALLOC;
+      $$->i.type = AGGR_ITEM_STATIC_ATTR;
+      $$->i.sa = $1;
+    }
+  ;
+
+CF_CODE
+
+CF_END