mirror of
https://gitlab.nic.cz/labs/bird.git
synced 2024-12-22 09:41:54 +00:00
Implement basics of prefix aggregation functionality
This commit is contained in:
Igor Putovny
parent
0a408c22f6
commit
e94c9cbf36
@ -46,6 +46,7 @@
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#include "proto/aggregator/aggregator.h"
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#include <stdlib.h>
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#include <assert.h>
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/*
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#include "nest/route.h"
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#include "nest/iface.h"
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@ -64,6 +65,430 @@
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extern linpool *rte_update_pool;
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static inline int
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is_leaf(const struct trie_node *node)
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{
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assert(node != NULL);
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return !node->child[0] && !node->child[1];
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}
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static struct trie_node *
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new_node(slab *trie_slab)
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{
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struct trie_node *new = sl_alloc(trie_slab);
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assert(new != NULL);
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*new = (struct trie_node) {
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.parent = NULL,
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.child = { NULL, NULL },
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.potential_buckets_count = 0,
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};
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return new;
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}
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/*
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* Mark appropriate child of parent node as NULL and free @node
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*/
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static void
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remove_node(struct trie_node *node)
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{
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assert(node != NULL);
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assert(node->parent != NULL);
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assert(node->child[0] == NULL && node->child[1] == NULL);
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if (node->parent->child[0] == node)
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node->parent->child[0] = NULL;
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else if (node->parent->child[1] == node)
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node->parent->child[1] = NULL;
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else
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bug("Invalid child pointer");
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sl_free(node);
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}
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static void
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trie_init(struct aggregator_proto *p)
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{
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static int inits = 0;
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p->trie_slab = sl_new(p->p.pool, sizeof(struct trie_node));
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p->root = new_node(p->trie_slab);
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inits++;
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log("Trie inits: %d", inits);
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}
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/*
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* Insert prefix in @addr to prefix trie with root at @node
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*/
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static void
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trie_insert_prefix(const union net_addr_union *addr, struct aggregator_bucket *bucket, struct trie_node *node, slab *trie_slab)
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{
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assert(addr != NULL);
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assert(node != NULL);
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if (addr->n.type != NET_IP4)
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return;
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const struct net_addr_ip4 * const ip4 = &addr->ip4;
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for (u32 i = 0; i < ip4->pxlen; i++)
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{
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u32 bit = (ip4->prefix.addr >> (31 - i)) & 1;
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if (!node->child[bit])
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{
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struct trie_node *new = new_node(trie_slab);
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new->parent = node;
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node->child[bit] = new;
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}
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node = node->child[bit];
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if ((int)i == ip4->pxlen - 1)
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node->bucket = bucket;
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}
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}
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static void
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first_pass(struct trie_node *node, slab *trie_slab)
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{
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assert(node != NULL);
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if (is_leaf(node))
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return;
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for (int i = 0; i < 2; i++)
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{
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if (!node->child[i])
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{
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node->child[i] = new_node(trie_slab);
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*node->child[i] = (struct trie_node) {
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.parent = node,
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.child[0] = NULL,
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.child[1] = NULL,
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.bucket = node->parent ? node->parent->bucket : NULL,
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.potential_buckets_count = 0,
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};
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}
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}
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first_pass(node->child[0], trie_slab);
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first_pass(node->child[1], trie_slab);
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}
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static int
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aggregator_bucket_compare(const void *a, const void *b)
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{
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if (a == NULL && b == NULL)
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return 0;
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if (a == NULL)
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return -1;
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if (b == NULL)
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return 1;
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assert(a != NULL);
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assert(b != NULL);
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const struct aggregator_bucket *fst = *(struct aggregator_bucket **)a;
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const struct aggregator_bucket *snd = *(struct aggregator_bucket **)b;
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if (fst < snd)
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return -1;
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if (fst > snd)
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return 1;
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return 0;
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}
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static void
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aggregator_bucket_intersection(struct trie_node *node, const struct trie_node *left, const struct trie_node *right)
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{
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assert(node != NULL);
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assert(left != NULL);
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assert(right != NULL);
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int i = 0;
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int j = 0;
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while (i < left->potential_buckets_count && j < right->potential_buckets_count)
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{
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if (node->potential_buckets_count >= MAX_POTENTIAL_NEXTHOP_COUNT)
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return;
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int res = aggregator_bucket_compare(left->potential_buckets[i], right->potential_buckets[j]);
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if (res == 0)
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{
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node->potential_buckets[node->potential_buckets_count++] = left->potential_buckets[i];
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i++;
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j++;
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}
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else if (res == -1)
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node->potential_buckets[node->potential_buckets_count++] = left->potential_buckets[i++];
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else if (res == 1)
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node->potential_buckets[node->potential_buckets_count++] = right->potential_buckets[j++];
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}
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}
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static void
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aggregator_bucket_union(struct trie_node *node, const struct trie_node *left, const struct trie_node *right)
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{
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assert(node != NULL);
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assert(left != NULL);
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assert(right != NULL);
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int i = 0;
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int j = 0;
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while (i < left->potential_buckets_count && j < right->potential_buckets_count)
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{
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if (node->potential_buckets_count >= MAX_POTENTIAL_NEXTHOP_COUNT)
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return;
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int res = aggregator_bucket_compare(left->potential_buckets[i], right->potential_buckets[j]);
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if (res == 0)
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{
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node->potential_buckets[node->potential_buckets_count++] = left->potential_buckets[i];
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i++;
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j++;
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}
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else if (res == -1)
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node->potential_buckets[node->potential_buckets_count++] = left->potential_buckets[i++];
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else if (res == 1)
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node->potential_buckets[node->potential_buckets_count++] = right->potential_buckets[j++];
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}
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while (i < left->potential_buckets_count)
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{
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if (node->potential_buckets_count >= MAX_POTENTIAL_NEXTHOP_COUNT)
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return;
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node->potential_buckets[node->potential_buckets_count++] = left->potential_buckets[i++];
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}
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while (j < right->potential_buckets_count)
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{
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if (node->potential_buckets_count >= MAX_POTENTIAL_NEXTHOP_COUNT)
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return;
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node->potential_buckets[node->potential_buckets_count++] = right->potential_buckets[j++];
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}
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}
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/*
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* Check if sets of potential buckets of two nodes are disjoint
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*/
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static int
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bucket_sets_are_disjoint(const struct trie_node *left, const struct trie_node *right)
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{
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assert(left != NULL);
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assert(right != NULL);
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if (left->potential_buckets_count == 0 || right->potential_buckets_count == 0)
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return 1;
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int i = 0;
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int j = 0;
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while (i < left->potential_buckets_count && j < right->potential_buckets_count)
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{
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int res = aggregator_bucket_compare(left->potential_buckets[i], right->potential_buckets[j]);
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if (res == 0)
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return 0;
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else if (res == -1)
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i++;
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else if (res == 1)
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j++;
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}
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return 1;
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}
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static void
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second_pass(struct trie_node *node)
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{
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assert(node != NULL);
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/* Potential nexthop is assigned to nexthop assigned during first pass */
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if (is_leaf(node))
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{
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node->potential_buckets[node->potential_buckets_count++] = node->bucket;
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return;
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}
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struct trie_node * const left = node->child[0];
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struct trie_node * const right = node->child[1];
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assert(left != NULL);
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assert(right != NULL);
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//assert(left->potential_buckets_count > 0);
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//assert(right->potential_buckets_count > 0);
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second_pass(left);
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second_pass(right);
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qsort(left->potential_buckets, left->potential_buckets_count, sizeof(struct aggregator_bucket *), aggregator_bucket_compare);
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qsort(right->potential_buckets, right->potential_buckets_count, sizeof(struct aggregator_bucket *), aggregator_bucket_compare);
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if (bucket_sets_are_disjoint(left, right))
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aggregator_bucket_union(node, left, right);
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else
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aggregator_bucket_intersection(node, left, right);
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}
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/*
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* Check if @bucket is one of potential nexthop buckets in @node
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*/
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static int
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bucket_is_present(const struct aggregator_bucket *bucket, const struct trie_node *node)
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{
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for (int i = 0; i < node->potential_buckets_count; i++)
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if (node->potential_buckets[i] == bucket)
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return 1;
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return 0;
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}
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static void
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third_pass_helper(struct trie_node *node)
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{
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if (!node)
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return;
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assert(node->parent != NULL);
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if (node->parent->bucket == NULL || bucket_is_present(node->parent->bucket, node))
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node->bucket = NULL;
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else
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{
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assert(node->potential_buckets_count > 0);
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node->bucket = node->potential_buckets[0];
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}
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third_pass_helper(node->child[0]);
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third_pass_helper(node->child[1]);
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/* Leaf node with unassigned nexthop is deleted */
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if (is_leaf(node) && node->bucket == NULL)
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remove_node(node);
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}
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static void
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third_pass(struct trie_node *node)
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{
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assert(node != NULL);
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if (!node)
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return;
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/* Node is a root */
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if (!node->parent)
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{
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assert(node->child[0] != NULL);
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assert(node->child[1] != NULL);
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assert(node->potential_buckets_count > 0);
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if (node->potential_buckets_count > 0)
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{
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node->bucket = node->potential_buckets[0];
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third_pass_helper(node->child[0]);
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third_pass_helper(node->child[1]);
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}
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}
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}
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static void
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get_trie_prefix_count_helper(const struct trie_node *node, int *count)
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{
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if (is_leaf(node))
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{
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*count += 1;
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return;
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}
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if (node->child[0])
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get_trie_prefix_count_helper(node->child[0], count);
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if (node->child[1])
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get_trie_prefix_count_helper(node->child[1], count);
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}
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static int
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get_trie_prefix_count(const struct trie_node *node)
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{
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int count = 0;
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get_trie_prefix_count_helper(node, &count);
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return count;
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}
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static void
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get_trie_depth_helper(const struct trie_node *node, int *result, int depth)
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{
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if (is_leaf(node))
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{
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if (depth > *result)
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*result = depth;
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return;
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}
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if (node->child[0])
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get_trie_depth_helper(node->child[0], result, depth + 1);
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if (node->child[1])
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get_trie_depth_helper(node->child[1], result, depth + 1);
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}
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static int
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get_trie_depth(const struct trie_node *node)
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{
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int result = 0;
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get_trie_depth_helper(node, &result, 0);
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return result;
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}
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static void
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extract_prefixes_helper(const struct trie_node *node, struct aggregated_prefixes * const prefixes, ip4_addr prefix, int depth)
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{
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assert(node != NULL);
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assert(prefixes != NULL);
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log("extracting: %I4", _I(prefix));
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if (is_leaf(node))
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{
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// assert(node->bucket != NULL);
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assert(prefixes->count < prefixes->capacity);
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prefixes->prefix_buckets[prefixes->count++] = (struct prefix_bucket) {
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.trie_prefix = NET_ADDR_IP4(_I(prefix), depth),
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.bucket = node->bucket ? node->bucket : NULL,
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};
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return;
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}
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if (node->child[0])
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extract_prefixes_helper(node->child[0], prefixes, _MI4(_I(prefix) | (0 << (31 - depth))), depth + 1);
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if (node->child[1])
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extract_prefixes_helper(node->child[1], prefixes, _MI4(_I(prefix) | (1 << (31 - depth))), depth + 1);
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}
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static void
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extract_prefixes(const struct trie_node *node, struct aggregated_prefixes *prefixes)
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{
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extract_prefixes_helper(node, prefixes, _MI4(0), 0);
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}
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/*
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* Set static attribute in @rta from static attribute in @old according to @sa.
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*/
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@ -594,6 +1019,59 @@ aggregator_rt_notify(struct proto *P, struct channel *src_ch, net *net, rte *new
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sl_free(old_route);
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}
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trie_init(p);
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HASH_WALK(p->buckets, next_hash, bucket)
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{
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for (const struct rte *rte = bucket->rte; rte; rte = rte->next)
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{
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union net_addr_union *uptr = (net_addr_union *)rte->net->n.addr;
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trie_insert_prefix(uptr, bucket, p->root, p->trie_slab);
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}
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}
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HASH_WALK_END;
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assert(p->root != NULL);
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assert(p->trie_slab != NULL);
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log("protocol: %p, root: %p, slab: %p", p, p->root, p->trie_slab);
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log("Number of prefixes before aggregation: %d", get_trie_prefix_count(p->root));
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log("Trie depth before aggregation: %d", get_trie_depth(p->root));
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first_pass(p->root, p->trie_slab);
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log("Trie depth after first pass: %d", get_trie_depth(p->root));
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second_pass(p->root);
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log("Trie depth after second pass: %d", get_trie_depth(p->root));
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third_pass(p->root);
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log("Trie depth after third pass: %d", get_trie_depth(p->root));
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if (is_leaf(p->root))
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log("WARNING: root is leaf!");
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const int prefix_count = get_trie_prefix_count(p->root);
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struct aggregated_prefixes *prefixes = allocz(sizeof(struct aggregated_prefixes) + sizeof(struct prefix_bucket) * prefix_count);
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prefixes->capacity = prefix_count;
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prefixes->count = 0;
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log("Number of prefixes after aggregation: %d", prefix_count);
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extract_prefixes(p->root, prefixes);
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log("Aggregated prefixes count: %d", prefixes->count);
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log("Trie depth: %d", get_trie_depth(p->root));
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assert(prefixes->count == prefix_count);
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struct buffer buf;
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LOG_BUFFER_INIT(buf);
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for (int i = 0; i < prefixes->count; i++)
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{
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int res = buffer_print(&buf, "%I4", prefixes->prefix_buckets[i].trie_prefix.prefix);
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assert(res != -1);
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}
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log("%s", buf.start);
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/* Announce changes */
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if (old_bucket)
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aggregator_bucket_update(p, old_bucket, net);
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@ -17,6 +17,8 @@
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#include "nest/protocol.h"
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#include "lib/hash.h"
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#define MAX_POTENTIAL_NEXTHOP_COUNT 16
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struct aggregator_config {
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struct proto_config c;
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struct channel_config *src, *dst;
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@ -61,6 +63,10 @@ struct aggregator_proto {
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/* Merge filter */
|
||||
const struct f_line *merge_by;
|
||||
event reload_buckets;
|
||||
|
||||
/* Aggregation trie */
|
||||
slab *trie_slab;
|
||||
struct trie_node *root;
|
||||
};
|
||||
|
||||
enum aggr_item_type {
|
||||
@ -83,4 +89,23 @@ struct aggr_item_node {
|
||||
struct aggr_item i;
|
||||
};
|
||||
|
||||
struct trie_node {
|
||||
struct trie_node *parent;
|
||||
struct trie_node *child[2];
|
||||
struct aggregator_bucket *bucket;
|
||||
struct aggregator_bucket *potential_buckets[MAX_POTENTIAL_NEXTHOP_COUNT];
|
||||
int potential_buckets_count;
|
||||
};
|
||||
|
||||
struct prefix_bucket {
|
||||
net_addr_ip4 trie_prefix;
|
||||
struct aggregator_bucket *bucket;
|
||||
};
|
||||
|
||||
struct aggregated_prefixes {
|
||||
int count;
|
||||
int capacity;
|
||||
struct prefix_bucket prefix_buckets[];
|
||||
};
|
||||
|
||||
#endif
|
||||
|
||||
Loading…
Reference in New Issue
Block a user