[location/libloc.git] / src / writer.c

/*
        libloc - A library to determine the location of someone on the Internet

        Copyright (C) 2017 IPFire Development Team <info@ipfire.org>

        This library is free software; you can redistribute it and/or
        modify it under the terms of the GNU Lesser General Public
        License as published by the Free Software Foundation; either
        version 2.1 of the License, or (at your option) any later version.

        This library is distributed in the hope that it will be useful,
        but WITHOUT ANY WARRANTY; without even the implied warranty of
        MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
        Lesser General Public License for more details.
*/

#include <assert.h>
#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/queue.h>
#include <time.h>

#ifdef HAVE_ENDIAN_H
#  include <endian.h>
#endif

#include <openssl/bio.h>
#include <openssl/err.h>
#include <openssl/evp.h>
#include <openssl/pem.h>

#include <loc/libloc.h>
#include <loc/as.h>
#include <loc/compat.h>
#include <loc/country.h>
#include <loc/database.h>
#include <loc/format.h>
#include <loc/network.h>
#include <loc/private.h>
#include <loc/writer.h>

struct loc_writer {
        struct loc_ctx* ctx;
        int refcount;

        struct loc_stringpool* pool;
        off_t vendor;
        off_t description;
        off_t license;

        // Private key to sign any databases
        EVP_PKEY* private_key;

        struct loc_as** as;
        size_t as_count;

        struct loc_country** countries;
        size_t countries_count;

        struct loc_network_tree* networks;
};

static int parse_private_key(struct loc_writer* writer, FILE* f) {
        // Free any previously loaded keys
        if (writer->private_key)
                EVP_PKEY_free(writer->private_key);

        // Read the key
        writer->private_key = PEM_read_PrivateKey(f, NULL, NULL, NULL);

        // Log any errors
        if (!writer->private_key) {
                char* error = ERR_error_string(ERR_get_error(), NULL);
                ERROR(writer->ctx, "Could not parse private key: %s\n", error);

                return -1;
        }

        return 0;
}

LOC_EXPORT int loc_writer_new(struct loc_ctx* ctx, struct loc_writer** writer, FILE* fkey) {
        struct loc_writer* w = calloc(1, sizeof(*w));
        if (!w)
                return -ENOMEM;

        w->ctx = loc_ref(ctx);
        w->refcount = 1;

        int r = loc_stringpool_new(ctx, &w->pool);
        if (r) {
                loc_writer_unref(w);
                return r;
        }

        // Initialize the network tree
        r = loc_network_tree_new(ctx, &w->networks);
        if (r) {
                loc_writer_unref(w);
                return r;
        }

        // Load the private key to sign databases
        if (fkey) {
                r = parse_private_key(w, fkey);
                if (r) {
                        loc_writer_unref(w);
                        return r;
                }
        }

        *writer = w;
        return 0;
}

LOC_EXPORT struct loc_writer* loc_writer_ref(struct loc_writer* writer) {
        writer->refcount++;

        return writer;
}

static void loc_writer_free(struct loc_writer* writer) {
        DEBUG(writer->ctx, "Releasing writer at %p\n", writer);

        // Free private key
        if (writer->private_key)
                EVP_PKEY_free(writer->private_key);

        // Unref all AS
        for (unsigned int i = 0; i < writer->as_count; i++) {
                loc_as_unref(writer->as[i]);
        }

        // Release network tree
        if (writer->networks)
                loc_network_tree_unref(writer->networks);

        // Unref the string pool
        loc_stringpool_unref(writer->pool);

        loc_unref(writer->ctx);
        free(writer);
}

LOC_EXPORT struct loc_writer* loc_writer_unref(struct loc_writer* writer) {
        if (--writer->refcount > 0)
                return writer;

        loc_writer_free(writer);

        return NULL;
}

LOC_EXPORT const char* loc_writer_get_vendor(struct loc_writer* writer) {
        return loc_stringpool_get(writer->pool, writer->vendor);
}

LOC_EXPORT int loc_writer_set_vendor(struct loc_writer* writer, const char* vendor) {
        // Add the string to the string pool
        off_t offset = loc_stringpool_add(writer->pool, vendor);
        if (offset < 0)
                return offset;

        writer->vendor = offset;
        return 0;
}

LOC_EXPORT const char* loc_writer_get_description(struct loc_writer* writer) {
        return loc_stringpool_get(writer->pool, writer->description);
}

LOC_EXPORT int loc_writer_set_description(struct loc_writer* writer, const char* description) {
        // Add the string to the string pool
        off_t offset = loc_stringpool_add(writer->pool, description);
        if (offset < 0)
                return offset;

        writer->description = offset;
        return 0;
}

LOC_EXPORT const char* loc_writer_get_license(struct loc_writer* writer) {
        return loc_stringpool_get(writer->pool, writer->license);
}

LOC_EXPORT int loc_writer_set_license(struct loc_writer* writer, const char* license) {
        // Add the string to the string pool
        off_t offset = loc_stringpool_add(writer->pool, license);
        if (offset < 0)
                return offset;

        writer->license = offset;
        return 0;
}

static int __loc_as_cmp(const void* as1, const void* as2) {
        return loc_as_cmp(*(struct loc_as**)as1, *(struct loc_as**)as2);
}

LOC_EXPORT int loc_writer_add_as(struct loc_writer* writer, struct loc_as** as, uint32_t number) {
        int r = loc_as_new(writer->ctx, as, number);
        if (r)
                return r;

        // We have a new AS to add
        writer->as_count++;

        // Make space
        writer->as = realloc(writer->as, sizeof(*writer->as) * writer->as_count);
        if (!writer->as)
                return -ENOMEM;

        // Add as last element
        writer->as[writer->as_count - 1] = loc_as_ref(*as);

        // Sort everything
        qsort(writer->as, writer->as_count, sizeof(*writer->as), __loc_as_cmp);

        return 0;
}

LOC_EXPORT int loc_writer_add_network(struct loc_writer* writer, struct loc_network** network, const char* string) {
        int r;

        // Create a new network object
        r = loc_network_new_from_string(writer->ctx, network, string);
        if (r)
                return r;

        // Add it to the local tree
        return loc_network_tree_add_network(writer->networks, *network);
}

static int __loc_country_cmp(const void* country1, const void* country2) {
        return loc_country_cmp(*(struct loc_country**)country1, *(struct loc_country**)country2);
}

LOC_EXPORT int loc_writer_add_country(struct loc_writer* writer, struct loc_country** country, const char* country_code) {
        int r = loc_country_new(writer->ctx, country, country_code);
        if (r)
                return r;

        // We have a new country to add
        writer->countries_count++;

        // Make space
        writer->countries = realloc(writer->countries, sizeof(*writer->countries) * writer->countries_count);
        if (!writer->countries)
                return -ENOMEM;

        // Add as last element
        writer->countries[writer->countries_count - 1] = loc_country_ref(*country);

        // Sort everything
        qsort(writer->countries, writer->countries_count, sizeof(*writer->countries), __loc_country_cmp);

        return 0;
}

static void make_magic(struct loc_writer* writer, struct loc_database_magic* magic,
                enum loc_database_version version) {
        // Copy magic bytes
        for (unsigned int i = 0; i < strlen(LOC_DATABASE_MAGIC); i++)
                magic->magic[i] = LOC_DATABASE_MAGIC[i];

        // Set version
        magic->version = version;
}

static void align_page_boundary(off_t* offset, FILE* f) {
        // Move to next page boundary
        while (*offset % LOC_DATABASE_PAGE_SIZE > 0)
                *offset += fwrite("", 1, 1, f);
}

static int loc_database_write_pool(struct loc_writer* writer,
                struct loc_database_header_v1* header, off_t* offset, FILE* f) {
        // Save the offset of the pool section
        DEBUG(writer->ctx, "Pool starts at %jd bytes\n", (intmax_t)*offset);
        header->pool_offset = htobe32(*offset);

        // Write the pool
        size_t pool_length = loc_stringpool_write(writer->pool, f);
        *offset += pool_length;

        DEBUG(writer->ctx, "Pool has a length of %zu bytes\n", pool_length);
        header->pool_length = htobe32(pool_length);

        return 0;
}

static int loc_database_write_as_section(struct loc_writer* writer,
                struct loc_database_header_v1* header, off_t* offset, FILE* f) {
        DEBUG(writer->ctx, "AS section starts at %jd bytes\n", (intmax_t)*offset);
        header->as_offset = htobe32(*offset);

        size_t as_length = 0;

        struct loc_database_as_v1 as;
        for (unsigned int i = 0; i < writer->as_count; i++) {
                // Convert AS into database format
                loc_as_to_database_v1(writer->as[i], writer->pool, &as);

                // Write to disk
                *offset += fwrite(&as, 1, sizeof(as), f);
                as_length += sizeof(as);
        }

        DEBUG(writer->ctx, "AS section has a length of %zu bytes\n", as_length);
        header->as_length = htobe32(as_length);

        align_page_boundary(offset, f);

        return 0;
}

struct node {
        TAILQ_ENTRY(node) nodes;

        struct loc_network_tree_node* node;

        // Indices of the child nodes
        uint32_t index_zero;
        uint32_t index_one;
};

static struct node* make_node(struct loc_network_tree_node* node) {
        struct node* n = malloc(sizeof(*n));
        if (!n)
                return NULL;

        n->node  = loc_network_tree_node_ref(node);
        n->index_zero = n->index_one = 0;

        return n;
}

static void free_node(struct node* node) {
        loc_network_tree_node_unref(node->node);

        free(node);
}

struct network {
        TAILQ_ENTRY(network) networks;

        struct loc_network* network;
};

static struct network* make_network(struct loc_network* network) {
        struct network* n = malloc(sizeof(*n));
        if (!n)
                return NULL;

        n->network = loc_network_ref(network);

        return n;
}

static void free_network(struct network* network) {
        loc_network_unref(network->network);

        free(network);
}

static int loc_database_write_networks(struct loc_writer* writer,
                struct loc_database_header_v1* header, off_t* offset, FILE* f) {
        // Write the network tree
        DEBUG(writer->ctx, "Network tree starts at %jd bytes\n", (intmax_t)*offset);
        header->network_tree_offset = htobe32(*offset);

        size_t network_tree_length = 0;
        size_t network_data_length = 0;

        struct node* node;
        struct node* child_node;

        uint32_t index = 0;
        uint32_t network_index = 0;

        struct loc_database_network_v1 db_network;
        struct loc_database_network_node_v1 db_node;

        // Initialize queue for nodes
        TAILQ_HEAD(node_t, node) nodes;
        TAILQ_INIT(&nodes);

        // Initialize queue for networks
        TAILQ_HEAD(network_t, network) networks;
        TAILQ_INIT(&networks);

        // Add root
        struct loc_network_tree_node* root = loc_network_tree_get_root(writer->networks);
        node = make_node(root);

        TAILQ_INSERT_TAIL(&nodes, node, nodes);

        while (!TAILQ_EMPTY(&nodes)) {
                // Pop first node in list
                node = TAILQ_FIRST(&nodes);
                TAILQ_REMOVE(&nodes, node, nodes);

                DEBUG(writer->ctx, "Processing node %p\n", node);

                // Get child nodes
                struct loc_network_tree_node* node_zero = loc_network_tree_node_get(node->node, 0);
                if (node_zero) {
                        node->index_zero = ++index;

                        child_node = make_node(node_zero);
                        loc_network_tree_node_unref(node_zero);

                        TAILQ_INSERT_TAIL(&nodes, child_node, nodes);
                }

                struct loc_network_tree_node* node_one = loc_network_tree_node_get(node->node, 1);
                if (node_one) {
                        node->index_one = ++index;

                        child_node = make_node(node_one);
                        loc_network_tree_node_unref(node_one);

                        TAILQ_INSERT_TAIL(&nodes, child_node, nodes);
                }

                // Prepare what we are writing to disk
                db_node.zero = htobe32(node->index_zero);
                db_node.one  = htobe32(node->index_one);

                if (loc_network_tree_node_is_leaf(node->node)) {
                        struct loc_network* network = loc_network_tree_node_get_network(node->node);

                        // Append network to be written out later
                        struct network* nw = make_network(network);
                        TAILQ_INSERT_TAIL(&networks, nw, networks);

                        db_node.network = htobe32(network_index++);
                        loc_network_unref(network);
                } else {
                        db_node.network = htobe32(0xffffffff);
                }

                // Write the current node
                DEBUG(writer->ctx, "Writing node %p (0 = %d, 1 = %d)\n",
                        node, node->index_zero, node->index_one);

                *offset += fwrite(&db_node, 1, sizeof(db_node), f);
                network_tree_length += sizeof(db_node);

                free_node(node);
        }

        loc_network_tree_node_unref(root);

        header->network_tree_length = htobe32(network_tree_length);

        align_page_boundary(offset, f);

        DEBUG(writer->ctx, "Networks data section starts at %jd bytes\n", (intmax_t)*offset);
        header->network_data_offset = htobe32(*offset);

        // We have now written the entire tree and have all networks
        // in a queue in order as they are indexed
        while (!TAILQ_EMPTY(&networks)) {
                struct network* nw = TAILQ_FIRST(&networks);
                TAILQ_REMOVE(&networks, nw, networks);

                // Prepare what we are writing to disk
                int r = loc_network_to_database_v1(nw->network, &db_network);
                if (r)
                        return r;

                *offset += fwrite(&db_network, 1, sizeof(db_network), f);
                network_data_length += sizeof(db_network);

                free_network(nw);
        }

        header->network_data_length = htobe32(network_data_length);

        align_page_boundary(offset, f);

        return 0;
}

static int loc_database_write_countries(struct loc_writer* writer,
                struct loc_database_header_v1* header, off_t* offset, FILE* f) {
        DEBUG(writer->ctx, "Countries section starts at %jd bytes\n", (intmax_t)*offset);
        header->countries_offset = htobe32(*offset);

        size_t countries_length = 0;

        struct loc_database_country_v1 country;
        for (unsigned int i = 0; i < writer->countries_count; i++) {
                // Convert country into database format
                loc_country_to_database_v1(writer->countries[i], writer->pool, &country);

                // Write to disk
                *offset += fwrite(&country, 1, sizeof(country), f);
                countries_length += sizeof(country);
        }

        DEBUG(writer->ctx, "Countries section has a length of %zu bytes\n", countries_length);
        header->countries_length = htobe32(countries_length);

        align_page_boundary(offset, f);

        return 0;
}

static int loc_writer_create_signature(struct loc_writer* writer,
                struct loc_database_header_v1* header, FILE* f) {
        DEBUG(writer->ctx, "Signing database...\n");

        // Read file from the beginning
        rewind(f);

        // Create a new context for signing
        EVP_MD_CTX* mdctx = EVP_MD_CTX_new();

        // Initialise the context
        int r = EVP_DigestSignInit(mdctx, NULL, NULL, NULL, writer->private_key);
        if (r != 1) {
                ERROR(writer->ctx, "%s\n", ERR_error_string(ERR_get_error(), NULL));
                goto END;
        }

        // Read magic
        struct loc_database_magic magic;
        fread(&magic, 1, sizeof(magic), f);

        hexdump(writer->ctx, &magic, sizeof(magic));

        // Feed magic into the signature
        r = EVP_DigestSignUpdate(mdctx, &magic, sizeof(magic));
        if (r != 1) {
                ERROR(writer->ctx, "%s\n", ERR_error_string(ERR_get_error(), NULL));
                goto END;
        }

        hexdump(writer->ctx, header, sizeof(*header));

        // Feed the header into the signature
        r = EVP_DigestSignUpdate(mdctx, header, sizeof(*header));
        if (r != 1) {
                ERROR(writer->ctx, "%s\n", ERR_error_string(ERR_get_error(), NULL));
                goto END;
        }

        // Skip header
        fseek(f, sizeof(*header), SEEK_CUR);

        // Walk through the file in chunks of 64kB
        char buffer[64 * 1024];
        while (!feof(f)) {
                size_t bytes_read = fread(buffer, 1, sizeof(buffer), f);

                if (ferror(f)) {
                        ERROR(writer->ctx, "Error reading from file: %s\n", strerror(errno));
                        r = errno;
                        goto END;
                }

                hexdump(writer->ctx, buffer, bytes_read);

                r = EVP_DigestSignUpdate(mdctx, buffer, bytes_read);
                if (r != 1) {
                        ERROR(writer->ctx, "%s\n", ERR_error_string(ERR_get_error(), NULL));
                        goto END;
                }
        }

        // Compute the signature
        size_t signature_length = sizeof(header->signature);

        r = EVP_DigestSignFinal(mdctx,
                (unsigned char*)header->signature, &signature_length);
        if (r != 1) {
                ERROR(writer->ctx, "%s\n", ERR_error_string(ERR_get_error(), NULL));
                goto END;
        }

        // Save length of the signature
        header->signature_length = htobe32(signature_length);

        DEBUG(writer->ctx, "Successfully generated signature of %lu bytes\n",
                signature_length);
        r = 0;

        // Dump signature
        hexdump(writer->ctx, header->signature, signature_length);

END:
        EVP_MD_CTX_free(mdctx);

        return r;
}

LOC_EXPORT int loc_writer_write(struct loc_writer* writer, FILE* f, enum loc_database_version version) {
        // Check version
        switch (version) {
                case LOC_DATABASE_VERSION_UNSET:
                        version = LOC_DATABASE_VERSION_LATEST;
                        break;

                case LOC_DATABASE_VERSION_1:
                        break;

                default:
                        ERROR(writer->ctx, "Invalid database version: %d\n", version);
                        return -1;
        }

        DEBUG(writer->ctx, "Writing database in version %d\n", version);

        struct loc_database_magic magic;
        make_magic(writer, &magic, version);

        // Make the header
        struct loc_database_header_v1 header;
        header.vendor      = htobe32(writer->vendor);
        header.description = htobe32(writer->description);
        header.license     = htobe32(writer->license);

        time_t now = time(NULL);
        header.created_at = htobe64(now);

        // Clear the signature
        header.signature_length = 0;
        for (unsigned int i = 0; i < sizeof(header.signature); i++)
                header.signature[i] = '\0';

        // Clear the padding
        for (unsigned int i = 0; i < sizeof(header.padding); i++)
                header.padding[i] = '\0';

        int r;
        off_t offset = 0;

        // Start writing at the beginning of the file
        r = fseek(f, 0, SEEK_SET);
        if (r)
                return r;

        // Write the magic
        offset += fwrite(&magic, 1, sizeof(magic), f);

        // Skip the space we need to write the header later
        r = fseek(f, sizeof(header), SEEK_CUR);
        if (r) {
                DEBUG(writer->ctx, "Could not seek to position after header\n");
                return r;
        }
        offset += sizeof(header);

        align_page_boundary(&offset, f);

        // Write all ASes
        r = loc_database_write_as_section(writer, &header, &offset, f);
        if (r)
                return r;

        // Write all networks
        r = loc_database_write_networks(writer, &header, &offset, f);
        if (r)
                return r;

        // Write countries
        r = loc_database_write_countries(writer, &header, &offset, f);
        if (r)
                return r;

        // Write pool
        r = loc_database_write_pool(writer, &header, &offset, f);
        if (r)
                return r;

        // Create the signature
        if (writer->private_key) {
                r = loc_writer_create_signature(writer, &header, f);
                if (r)
                        return r;
        }

        // Write the header
        r = fseek(f, sizeof(magic), SEEK_SET);
        if (r)
                return r;

        fwrite(&header, 1, sizeof(header), f);

        return r;
}