X-Git-Url: http://git.ipfire.org/?p=people%2Fms%2Flibloc.git;a=blobdiff_plain;f=src%2Fdatabase.c;h=fe5e6dc6e0ebcb86a56b5629dc982ff5bc879ff1;hp=9c07590f6cd3e10146e98848bfdc0375c51d8482;hb=273948cfa02a1bacf906f1b4dc296f81b7d8441e;hpb=3f35869aa908b35b296e2694b4f8bf7db8729f6a

diff --git a/src/database.c b/src/database.c
index 9c07590..fe5e6dc 100644
--- a/src/database.c
+++ b/src/database.c
@@ -15,40 +15,244 @@
 */
 
 #include <arpa/inet.h>
+#include <ctype.h>
+#include <endian.h>
 #include <errno.h>
+#include <netinet/in.h>
 #include <stddef.h>
 #include <stdint.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
+#include <sys/mman.h>
 #include <sys/types.h>
+#include <time.h>
 #include <unistd.h>
 
 #include <loc/libloc.h>
+#include <loc/as.h>
+#include <loc/database.h>
 #include <loc/format.h>
-
-#include "libloc-private.h"
-#include "as.h"
-#include "database.h"
-#include "stringpool.h"
+#include <loc/network.h>
+#include <loc/private.h>
+#include <loc/stringpool.h>
 
 struct loc_database {
 	struct loc_ctx* ctx;
 	int refcount;
 
-	FILE* file;
 	unsigned int version;
+	time_t created_at;
 	off_t vendor;
 	off_t description;
+	off_t license;
 
 	// ASes in the database
-	struct loc_as** as;
+	struct loc_database_as_v0* as_v0;
 	size_t as_count;
 
+	// Network tree
+	struct loc_database_network_node_v0* network_nodes_v0;
+	size_t network_nodes_count;
+
+	// Networks
+	struct loc_database_network_v0* networks_v0;
+	size_t networks_count;
+
 	struct loc_stringpool* pool;
 };
 
-LOC_EXPORT int loc_database_new(struct loc_ctx* ctx, struct loc_database** database, size_t pool_size) {
+struct loc_database_enumerator {
+	struct loc_ctx* ctx;
+	struct loc_database* db;
+	int refcount;
+
+	// Search string
+	char* string;
+
+	// Index of the AS we are looking at
+	unsigned int as_index;
+};
+
+static int loc_database_read_magic(struct loc_database* db, FILE* f) {
+	struct loc_database_magic magic;
+
+	// Read from file
+	size_t bytes_read = fread(&magic, 1, sizeof(magic), f);
+
+	// Check if we have been able to read enough data
+	if (bytes_read < sizeof(magic)) {
+		ERROR(db->ctx, "Could not read enough data to validate magic bytes\n");
+		DEBUG(db->ctx, "Read %zu bytes, but needed %zu\n", bytes_read, sizeof(magic));
+		return -ENOMSG;
+	}
+
+	// Compare magic bytes
+	if (memcmp(LOC_DATABASE_MAGIC, magic.magic, strlen(LOC_DATABASE_MAGIC)) == 0) {
+		DEBUG(db->ctx, "Magic value matches\n");
+
+		// Parse version
+		db->version = be16toh(magic.version);
+		DEBUG(db->ctx, "Database version is %u\n", db->version);
+
+		return 0;
+	}
+
+	ERROR(db->ctx, "Database format is not compatible\n");
+
+	// Return an error
+	return 1;
+}
+
+static int loc_database_read_as_section_v0(struct loc_database* db,
+		FILE* f, const struct loc_database_header_v0* header) {
+	off_t as_offset  = be32toh(header->as_offset);
+	size_t as_length = be32toh(header->as_length);
+
+	DEBUG(db->ctx, "Reading AS section from %jd (%zu bytes)\n", as_offset, as_length);
+
+	if (as_length > 0) {
+		db->as_v0 = mmap(NULL, as_length, PROT_READ,
+			MAP_SHARED, fileno(f), as_offset);
+
+		if (db->as_v0 == MAP_FAILED)
+			return -errno;
+	}
+
+	db->as_count = as_length / sizeof(*db->as_v0);
+
+	INFO(db->ctx, "Read %zu ASes from the database\n", db->as_count);
+
+	return 0;
+}
+
+static int loc_database_read_network_nodes_section_v0(struct loc_database* db,
+		FILE* f, const struct loc_database_header_v0* header) {
+	off_t network_nodes_offset  = be32toh(header->network_tree_offset);
+	size_t network_nodes_length = be32toh(header->network_tree_length);
+
+	DEBUG(db->ctx, "Reading network nodes section from %jd (%zu bytes)\n",
+		network_nodes_offset, network_nodes_length);
+
+	if (network_nodes_length > 0) {
+		db->network_nodes_v0 = mmap(NULL, network_nodes_length, PROT_READ,
+			MAP_SHARED, fileno(f), network_nodes_offset);
+
+		if (db->network_nodes_v0 == MAP_FAILED)
+			return -errno;
+	}
+
+	db->network_nodes_count = network_nodes_length / sizeof(*db->network_nodes_v0);
+
+	INFO(db->ctx, "Read %zu network nodes from the database\n", db->network_nodes_count);
+
+	return 0;
+}
+
+static int loc_database_read_networks_section_v0(struct loc_database* db,
+		FILE* f, const struct loc_database_header_v0* header) {
+	off_t networks_offset  = be32toh(header->network_data_offset);
+	size_t networks_length = be32toh(header->network_data_length);
+
+	DEBUG(db->ctx, "Reading networks section from %jd (%zu bytes)\n",
+		networks_offset, networks_length);
+
+	if (networks_length > 0) {
+		db->networks_v0 = mmap(NULL, networks_length, PROT_READ,
+			MAP_SHARED, fileno(f), networks_offset);
+
+		if (db->networks_v0 == MAP_FAILED)
+			return -errno;
+	}
+
+	db->networks_count = networks_length / sizeof(*db->networks_v0);
+
+	INFO(db->ctx, "Read %zu networks from the database\n", db->networks_count);
+
+	return 0;
+}
+
+static int loc_database_read_header_v0(struct loc_database* db, FILE* f) {
+	struct loc_database_header_v0 header;
+
+	// Read from file
+	size_t size = fread(&header, 1, sizeof(header), f);
+
+	if (size < sizeof(header)) {
+		ERROR(db->ctx, "Could not read enough data for header\n");
+		return -ENOMSG;
+	}
+
+	// Copy over data
+	db->created_at  = be64toh(header.created_at);
+	db->vendor      = be32toh(header.vendor);
+	db->description = be32toh(header.description);
+	db->license     = be32toh(header.license);
+
+	// Open pool
+	off_t pool_offset  = be32toh(header.pool_offset);
+	size_t pool_length = be32toh(header.pool_length);
+
+	int r = loc_stringpool_open(db->ctx, &db->pool,
+		f, pool_length, pool_offset);
+	if (r)
+		return r;
+
+	// AS section
+	r = loc_database_read_as_section_v0(db, f, &header);
+	if (r)
+		return r;
+
+	// Network Nodes
+	r = loc_database_read_network_nodes_section_v0(db, f, &header);
+	if (r)
+		return r;
+
+	// Networks
+	r = loc_database_read_networks_section_v0(db, f, &header);
+	if (r)
+		return r;
+
+	return 0;
+}
+
+static int loc_database_read_header(struct loc_database* db, FILE* f) {
+	switch (db->version) {
+		case 0:
+			return loc_database_read_header_v0(db, f);
+
+		default:
+			ERROR(db->ctx, "Incompatible database version: %u\n", db->version);
+			return 1;
+	}
+}
+
+static int loc_database_read(struct loc_database* db, FILE* f) {
+	clock_t start = clock();
+
+	// Read magic bytes
+	int r = loc_database_read_magic(db, f);
+	if (r)
+		return r;
+
+	// Read the header
+	r = loc_database_read_header(db, f);
+	if (r)
+		return r;
+
+	clock_t end = clock();
+
+	INFO(db->ctx, "Opened database in %.8fs\n",
+		(double)(end - start) / CLOCKS_PER_SEC);
+
+	return 0;
+}
+
+LOC_EXPORT int loc_database_new(struct loc_ctx* ctx, struct loc_database** database, FILE* f) {
+	// Fail on invalid file handle
+	if (!f)
+		return -EINVAL;
+
 	struct loc_database* db = calloc(1, sizeof(*db));
 	if (!db)
 		return -ENOMEM;
@@ -57,10 +261,9 @@ LOC_EXPORT int loc_database_new(struct loc_ctx* ctx, struct loc_database** datab
 	db->ctx = loc_ref(ctx);
 	db->refcount = 1;
 
-	DEBUG(db->ctx, "Database allocated at %p\n", db);
+	DEBUG(db->ctx, "Database object allocated at %p\n", db);
 
-	// Create string pool
-	int r = loc_stringpool_new(db->ctx, &db->pool, pool_size);
+	int r = loc_database_read(db, f);
 	if (r) {
 		loc_database_unref(db);
 		return r;
@@ -71,14 +274,6 @@ LOC_EXPORT int loc_database_new(struct loc_ctx* ctx, struct loc_database** datab
 	return 0;
 }
 
-LOC_EXPORT int loc_database_open(struct loc_ctx* ctx, struct loc_database** database, FILE* f) {
-	int r = loc_database_new(ctx, database, 0);
-	if (r)
-		return r;
-
-	return loc_database_read(*database, f);
-}
-
 LOC_EXPORT struct loc_database* loc_database_ref(struct loc_database* db) {
 	db->refcount++;
 
@@ -86,21 +281,32 @@ LOC_EXPORT struct loc_database* loc_database_ref(struct loc_database* db) {
 }
 
 static void loc_database_free(struct loc_database* db) {
+	int r;
+
 	DEBUG(db->ctx, "Releasing database %p\n", db);
 
-	// Remove references to all ASes
-	if (db->as) {
-		for (unsigned int i = 0; i < db->as_count; i++) {
-			loc_as_unref(db->as[i]);
-		}
-		free(db->as);
+	// Removing all ASes
+	if (db->as_v0) {
+		r = munmap(db->as_v0, db->as_count * sizeof(*db->as_v0));
+		if (r)
+			ERROR(db->ctx, "Could not unmap AS section: %s\n", strerror(errno));
 	}
 
-	loc_stringpool_unref(db->pool);
+	// Remove mapped network sections
+	if (db->networks_v0) {
+		r = munmap(db->networks_v0, db->networks_count * sizeof(*db->networks_v0));
+		if (r)
+			ERROR(db->ctx, "Could not unmap networks section: %s\n", strerror(errno));
+	}
+
+	// Remove mapped network nodes section
+	if (db->network_nodes_v0) {
+		r = munmap(db->network_nodes_v0, db->network_nodes_count * sizeof(*db->network_nodes_v0));
+		if (r)
+			ERROR(db->ctx, "Could not unmap network nodes section: %s\n", strerror(errno));
+	}
 
-	// Close file
-	if (db->file)
-		fclose(db->file);
+	loc_stringpool_unref(db->pool);
 
 	loc_unref(db->ctx);
 	free(db);
@@ -114,294 +320,321 @@ LOC_EXPORT struct loc_database* loc_database_unref(struct loc_database* db) {
 	return NULL;
 }
 
-LOC_EXPORT const char* loc_database_get_vendor(struct loc_database* db) {
-	return loc_stringpool_get(db->pool, db->vendor);
+LOC_EXPORT time_t loc_database_created_at(struct loc_database* db) {
+	return db->created_at;
 }
 
-LOC_EXPORT int loc_database_set_vendor(struct loc_database* db, const char* vendor) {
-	// Add the string to the string pool
-	off_t offset = loc_stringpool_add(db->pool, vendor);
-	if (offset < 0)
-		return offset;
-
-	db->vendor = offset;
-	return 0;
+LOC_EXPORT const char* loc_database_get_vendor(struct loc_database* db) {
+	return loc_stringpool_get(db->pool, db->vendor);
 }
 
 LOC_EXPORT const char* loc_database_get_description(struct loc_database* db) {
 	return loc_stringpool_get(db->pool, db->description);
 }
 
-LOC_EXPORT int loc_database_set_description(struct loc_database* db, const char* description) {
-	// Add the string to the string pool
-	off_t offset = loc_stringpool_add(db->pool, description);
-	if (offset < 0)
-		return offset;
-
-	db->description = offset;
-	return 0;
+LOC_EXPORT const char* loc_database_get_license(struct loc_database* db) {
+	return loc_stringpool_get(db->pool, db->license);
 }
 
 LOC_EXPORT size_t loc_database_count_as(struct loc_database* db) {
 	return db->as_count;
 }
 
-static int loc_database_has_as(struct loc_database* db, struct loc_as* as) {
-	for (unsigned int i = 0; i < db->as_count; i++) {
-		if (loc_as_cmp(as, db->as[i]) == 0)
-			return i;
+// Returns the AS at position pos
+static int loc_database_fetch_as(struct loc_database* db, struct loc_as** as, off_t pos) {
+	if ((size_t)pos >= db->as_count)
+		return -EINVAL;
+
+	DEBUG(db->ctx, "Fetching AS at position %jd\n", pos);
+
+	int r;
+	switch (db->version) {
+		case 0:
+			r = loc_as_new_from_database_v0(db->ctx, db->pool, as, db->as_v0 + pos);
+			break;
+
+		default:
+			return -1;
 	}
 
-	return -1;
-}
+	if (r == 0) {
+		DEBUG(db->ctx, "Got AS%u\n", loc_as_get_number(*as));
+	}
 
-static int __loc_as_cmp(const void* as1, const void* as2) {
-	return loc_as_cmp(*(struct loc_as**)as1, *(struct loc_as**)as2);
+	return r;
 }
 
-static void loc_database_sort_ases(struct loc_database* db) {
-	qsort(db->as, db->as_count, sizeof(*db->as), __loc_as_cmp);
-}
+// Performs a binary search to find the AS in the list
+LOC_EXPORT int loc_database_get_as(struct loc_database* db, struct loc_as** as, uint32_t number) {
+	off_t lo = 0;
+	off_t hi = db->as_count - 1;
 
-static struct loc_as* __loc_database_add_as(struct loc_database* db, struct loc_as* as) {
-	// Check if AS exists already
-	int i = loc_database_has_as(db, as);
-	if (i >= 0) {
-		loc_as_unref(as);
+	// Save start time
+	clock_t start = clock();
 
-		// Select already existing AS
-		as = db->as[i];
+	while (lo <= hi) {
+		off_t i = (lo + hi) / 2;
 
-		return loc_as_ref(as);
-	}
+		// Fetch AS in the middle between lo and hi
+		int r = loc_database_fetch_as(db, as, i);
+		if (r)
+			return r;
 
-	db->as_count++;
+		// Check if this is a match
+		uint32_t as_number = loc_as_get_number(*as);
+		if (as_number == number) {
+			clock_t end = clock();
 
-	// Make space for the new entry
-	db->as = realloc(db->as, sizeof(*db->as) * db->as_count);
+			// Log how fast this has been
+			DEBUG(db->ctx, "Found AS%u in %.8fs\n", as_number,
+				(double)(end - start) / CLOCKS_PER_SEC);
 
-	// Add the new entry at the end
-	db->as[db->as_count - 1] = loc_as_ref(as);
+			return 0;
+		}
 
-	// Sort everything
-	loc_database_sort_ases(db);
+		// If it wasn't, we release the AS and
+		// adjust our search pointers
+		loc_as_unref(*as);
 
-	return as;
-}
+		if (as_number < number) {
+			lo = i + 1;
+		} else
+			hi = i - 1;
+	}
 
-LOC_EXPORT struct loc_as* loc_database_add_as(struct loc_database* db, uint32_t number) {
-	struct loc_as* as;
-	int r = loc_as_new(db->ctx, db->pool, &as, number);
-	if (r)
-		return NULL;
+	// Nothing found
+	*as = NULL;
 
-	return __loc_database_add_as(db, as);
+	return 1;
 }
 
-static int loc_database_read_magic(struct loc_database* db) {
-	struct loc_database_magic magic;
-
-	// Read from file
-	size_t bytes_read = fread(&magic, 1, sizeof(magic), db->file);
+// Returns the network at position pos
+static int loc_database_fetch_network(struct loc_database* db, struct loc_network** network,
+		struct in6_addr* address, unsigned int prefix, off_t pos) {
+	if ((size_t)pos >= db->networks_count)
+		return -EINVAL;
 
-	// Check if we have been able to read enough data
-	if (bytes_read < sizeof(magic)) {
-		ERROR(db->ctx, "Could not read enough data to validate magic bytes\n");
-		DEBUG(db->ctx, "Read %zu bytes, but needed %zu\n", bytes_read, sizeof(magic));
-		return -ENOMSG;
-	}
+	DEBUG(db->ctx, "Fetching network at position %jd\n", pos);
 
-	// Compare magic bytes
-	if (memcmp(LOC_DATABASE_MAGIC, magic.magic, strlen(LOC_DATABASE_MAGIC)) == 0) {
-		DEBUG(db->ctx, "Magic value matches\n");
+	int r;
+	switch (db->version) {
+		case 0:
+			r = loc_network_new_from_database_v0(db->ctx, network,
+				address, prefix, db->networks_v0 + pos);
+			break;
 
-		// Parse version
-		db->version = ntohs(magic.version);
-		DEBUG(db->ctx, "Database version is %u\n", db->version);
+		default:
+			return -1;
+	}
 
-		return 0;
+	if (r == 0) {
+		char* string = loc_network_str(*network);
+		DEBUG(db->ctx, "Got network %s\n", string);
+		free(string);
 	}
 
-	ERROR(db->ctx, "Database format is not compatible\n");
+	return r;
+}
 
-	// Return an error
-	return 1;
+static int __loc_database_node_is_leaf(const struct loc_database_network_node_v0* node) {
+	return (node->network != htobe32(0xffffffff));
 }
 
-static int loc_database_read_as_section_v0(struct loc_database* db,
-		off_t as_offset, size_t as_length) {
-	struct loc_database_as_v0 dbobj;
+static int __loc_database_lookup_handle_leaf(struct loc_database* db, const struct in6_addr* address,
+		struct loc_network** network, struct in6_addr* network_address, unsigned int prefix,
+		const struct loc_database_network_node_v0* node) {
+	off_t network_index = be32toh(node->network);
 
-	// Read from the start of the section
-	int r = fseek(db->file, as_offset, SEEK_SET);
-	if (r)
-		return r;
+	DEBUG(db->ctx, "Handling leaf node at %jd (%jd)\n", node - db->network_nodes_v0, network_index);
 
-	// Read all ASes
-	size_t as_count = as_length / sizeof(dbobj);
-	for (unsigned int i = 0; i < as_count; i++) {
-		size_t bytes_read = fread(&dbobj, 1, sizeof(dbobj), db->file);
-		if (bytes_read < sizeof(dbobj)) {
-			ERROR(db->ctx, "Could not read an AS object\n");
-			return -ENOMSG;
-		}
+	// Fetch the network
+	int r = loc_database_fetch_network(db, network,
+		network_address, prefix, network_index);
+	if (r) {
+		ERROR(db->ctx, "Could not fetch network %jd from database\n", network_index);
+		return r;
+	}
 
-		// Allocate a new AS
-		struct loc_as* as;
-		r = loc_as_new_from_database_v0(db->ctx, db->pool, &as, &dbobj);
-		if (r)
-			return r;
+	// Check if the given IP address is inside the network
+	r = loc_network_match_address(*network, address);
+	if (r) {
+		DEBUG(db->ctx, "Searched address is not part of the network\n");
 
-		// Attach it to the database
-		as = __loc_database_add_as(db, as);
-		loc_as_unref(as);
+		loc_network_unref(*network);
+		*network = NULL;
+		return 1;
 	}
 
-	INFO(db->ctx, "Read %zu ASes from the database\n", db->as_count);
-
+	// A network was found and the IP address matches
 	return 0;
 }
 
-static int loc_database_read_header_v0(struct loc_database* db) {
-	struct loc_database_header_v0 header;
+// Searches for an exact match along the path
+static int __loc_database_lookup(struct loc_database* db, const struct in6_addr* address,
+		struct loc_network** network, struct in6_addr* network_address,
+		const struct loc_database_network_node_v0* node, unsigned int level) {
+	int r;
+	off_t node_index;
+
+	// Follow the path
+	int bit = in6_addr_get_bit(address, level);
+	in6_addr_set_bit(network_address, level, bit);
+
+	if (bit == 0)
+		node_index = be32toh(node->zero);
+	else
+		node_index = be32toh(node->one);
+
+	// If the node index is zero, the tree ends here
+	// and we cannot descend any further
+	if (node_index > 0) {
+		// Check boundaries
+		if ((size_t)node_index >= db->network_nodes_count)
+			return -EINVAL;
+
+		// Move on to the next node
+		r = __loc_database_lookup(db, address, network, network_address,
+			db->network_nodes_v0 + node_index, level + 1);
+
+		// End here if a result was found
+		if (r == 0)
+			return r;
 
-	// Read from file
-	size_t size = fread(&header, 1, sizeof(header), db->file);
+		// Raise any errors
+		else if (r < 0)
+			return r;
 
-	if (size < sizeof(header)) {
-		ERROR(db->ctx, "Could not read enough data for header\n");
-		return -ENOMSG;
+		DEBUG(db->ctx, "No match found below level %u\n", level);
+	} else {
+		DEBUG(db->ctx, "Tree ended at level %u\n", level);
 	}
 
-	// Copy over data
-	db->vendor      = ntohl(header.vendor);
-	db->description = ntohl(header.description);
-
-	// Open pool
-	off_t pool_offset  = ntohl(header.pool_offset);
-	size_t pool_length = ntohl(header.pool_length);
+	// If this node has a leaf, we will check if it matches
+	if (__loc_database_node_is_leaf(node)) {
+		r = __loc_database_lookup_handle_leaf(db, address, network, network_address, level, node);
+		if (r <= 0)
+			return r;
+	}
 
-	int r = loc_stringpool_read(db->pool, db->file, pool_offset, pool_length);
-	if (r)
-		return r;
+	return 1;
+}
 
-	// AS section
-	off_t as_offset  = ntohl(header.as_offset);
-	size_t as_length = ntohl(header.as_length);
+LOC_EXPORT int loc_database_lookup(struct loc_database* db,
+		struct in6_addr* address, struct loc_network** network) {
+	struct in6_addr network_address;
+	memset(&network_address, 0, sizeof(network_address));
 
-	r = loc_database_read_as_section_v0(db, as_offset, as_length);
-	if (r)
-		return r;
+	*network = NULL;
 
-	return 0;
-}
+	// Save start time
+	clock_t start = clock();
 
-static int loc_database_read_header(struct loc_database* db) {
-	switch (db->version) {
-		case 0:
-			return loc_database_read_header_v0(db);
+	int r = __loc_database_lookup(db, address, network, &network_address,
+		db->network_nodes_v0, 0);
 
-		default:
-			ERROR(db->ctx, "Incompatible database version: %u\n", db->version);
-			return 1;
-	}
-}
+	clock_t end = clock();
 
-LOC_EXPORT int loc_database_read(struct loc_database* db, FILE* f) {
-	// Copy the file pointer and work on that so we don't care if
-	// the calling function closes the file
-	int fd = fileno(f);
+	// Log how fast this has been
+	DEBUG(db->ctx, "Executed network search in %.8fs\n",
+		(double)(end - start) / CLOCKS_PER_SEC);
 
-	// Make a copy
-	fd = dup(fd);
+	return r;
+}
 
-	// Retrieve a file pointer
-	db->file = fdopen(fd, "r");
-	if (!db->file)
-		return -errno;
+LOC_EXPORT int loc_database_lookup_from_string(struct loc_database* db,
+		const char* string, struct loc_network** network) {
+	struct in6_addr address;
 
-	int r = fseek(db->file, 0, SEEK_SET);
+	int r = loc_parse_address(db->ctx, string, &address);
 	if (r)
 		return r;
 
-	// Read magic bytes
-	r = loc_database_read_magic(db);
-	if (r)
-		return r;
+	return loc_database_lookup(db, &address, network);
+}
 
-	// Read the header
-	r = loc_database_read_header(db);
-	if (r)
-		return r;
+// Enumerator
 
+LOC_EXPORT int loc_database_enumerator_new(struct loc_database_enumerator** enumerator, struct loc_database* db) {
+	struct loc_database_enumerator* e = calloc(1, sizeof(*e));
+	if (!e)
+		return -ENOMEM;
+
+	// Reference context
+	e->ctx = loc_ref(db->ctx);
+	e->db = loc_database_ref(db);
+	e->refcount = 1;
+
+	DEBUG(e->ctx, "Database enumerator object allocated at %p\n", e);
+
+	*enumerator = e;
 	return 0;
 }
 
-static void loc_database_make_magic(struct loc_database* db, struct loc_database_magic* magic) {
-	// Copy magic bytes
-	for (unsigned int i = 0; i < strlen(LOC_DATABASE_MAGIC); i++)
-		magic->magic[i] = LOC_DATABASE_MAGIC[i];
+LOC_EXPORT struct loc_database_enumerator* loc_database_enumerator_ref(struct loc_database_enumerator* enumerator) {
+	enumerator->refcount++;
 
-	// Set version
-	magic->version = htons(LOC_DATABASE_VERSION);
+	return enumerator;
 }
 
-LOC_EXPORT int loc_database_write(struct loc_database* db, FILE* f) {
-	struct loc_database_magic magic;
-	loc_database_make_magic(db, &magic);
+static void loc_database_enumerator_free(struct loc_database_enumerator* enumerator) {
+	DEBUG(enumerator->ctx, "Releasing database enumerator %p\n", enumerator);
 
-	// Make the header
-	struct loc_database_header_v0 header;
-	header.vendor      = htonl(db->vendor);
-	header.description = htonl(db->description);
+	// Release all references
+	loc_database_unref(enumerator->db);
+	loc_unref(enumerator->ctx);
 
-	int r;
-	off_t offset = 0;
+	if (enumerator->string)
+		free(enumerator->string);
 
-	// Start writing at the beginning of the file
-	r = fseek(f, 0, SEEK_SET);
-	if (r)
-		return r;
+	free(enumerator);
+}
 
-	// Write the magic
-	offset += fwrite(&magic, 1, sizeof(magic), f);
+LOC_EXPORT struct loc_database_enumerator* loc_database_enumerator_unref(struct loc_database_enumerator* enumerator) {
+	if (!enumerator)
+		return NULL;
 
-	// Skip the space we need to write the header later
-	r = fseek(f, sizeof(header), SEEK_CUR);
-	if (r) {
-		DEBUG(db->ctx, "Could not seek to position after header\n");
-		return r;
-	}
-	offset += sizeof(header);
+	if (--enumerator->refcount > 0)
+		return enumerator;
 
-	// Write all ASes
-	header.as_offset = htonl(offset);
+	loc_database_enumerator_free(enumerator);
+	return NULL;
+}
 
-	struct loc_database_as_v0 dbas;
-	for (unsigned int i = 0; i < db->as_count; i++) {
-		// Convert AS into database format
-		loc_as_to_database_v0(db->as[i], &dbas);
+LOC_EXPORT int loc_database_enumerator_set_string(struct loc_database_enumerator* enumerator, const char* string) {
+	enumerator->string = strdup(string);
 
-		// Write to disk
-		offset += fwrite(&dbas, 1, sizeof(dbas), f);
-	}
-	header.as_length = htonl(db->as_count * sizeof(dbas));
+	// Make the string lowercase
+	for (char *p = enumerator->string; *p; p++)
+		*p = tolower(*p);
 
-	// Save the offset of the pool section
-	DEBUG(db->ctx, "Pool starts at %jd bytes\n", offset);
-	header.pool_offset = htonl(offset);
+	return 0;
+}
 
-	// Size of the pool
-	size_t pool_length = loc_stringpool_write(db->pool, f);
-	DEBUG(db->ctx, "Pool has a length of %zu bytes\n", pool_length);
-	header.pool_length = htonl(pool_length);
+LOC_EXPORT struct loc_as* loc_database_enumerator_next_as(struct loc_database_enumerator* enumerator) {
+	struct loc_database* db = enumerator->db;
+	struct loc_as* as;
 
-	// Write the header
-	r = fseek(f, sizeof(magic), SEEK_SET);
-	if (r)
-		return r;
+	while (enumerator->as_index < db->as_count) {
+		// Fetch the next AS
+		int r = loc_database_fetch_as(db, &as, enumerator->as_index++);
+		if (r)
+			return NULL;
 
-	offset += fwrite(&header, 1, sizeof(header), f);
+		r = loc_as_match_string(as, enumerator->string);
+		if (r == 1) {
+			DEBUG(enumerator->ctx, "AS%d (%s) matches %s\n",
+				loc_as_get_number(as), loc_as_get_name(as), enumerator->string);
 
-	return 0;
+			return as;
+		}
+
+		// No match
+		loc_as_unref(as);
+	}
+
+	// Reset the index
+	enumerator->as_index = 0;
+
+	// We have searched through all of them
+	return NULL;
 }