diff options
Diffstat (limited to 'openbsc/src/nat/bsc_nat.c')
| -rw-r--r-- | openbsc/src/nat/bsc_nat.c | 802 |
1 files changed, 802 insertions, 0 deletions
diff --git a/openbsc/src/nat/bsc_nat.c b/openbsc/src/nat/bsc_nat.c new file mode 100644 index 000000000..09df4dcb6 --- /dev/null +++ b/openbsc/src/nat/bsc_nat.c @@ -0,0 +1,802 @@ +/* BSC Multiplexer/NAT */ + +/* + * (C) 2010 by Holger Hans Peter Freyther <zecke@selfish.org> + * (C) 2010 by on-waves.com + * (C) 2009 by Harald Welte <laforge@gnumonks.org> + * All Rights Reserved + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2 of the License, or + * (at your option) any later version. + * + * This program 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 General Public License for more details. + * + * You should have received a copy of the GNU General Public License along + * with this program; if not, write to the Free Software Foundation, Inc., + * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA. + * + */ +#include <sys/socket.h> +#include <netinet/in.h> +#include <arpa/inet.h> + +#include <errno.h> +#include <signal.h> +#include <stdio.h> +#include <stdlib.h> +#include <time.h> +#include <unistd.h> + +#define _GNU_SOURCE +#include <getopt.h> + +#include <openbsc/debug.h> +#include <openbsc/bsc_msc.h> +#include <openbsc/bsc_nat.h> +#include <openbsc/bssap.h> +#include <openbsc/ipaccess.h> +#include <openbsc/abis_nm.h> +#include <openbsc/telnet_interface.h> + +#include <osmocore/talloc.h> + +#include <vty/vty.h> + +#include <sccp/sccp.h> + +struct debug_target *stderr_target; +static const char *config_file = "bsc-nat.cfg"; +static char *msc_address = "127.0.0.1"; +static struct in_addr local_addr; +static struct bsc_fd msc_connection; +static struct bsc_fd bsc_connection; + + +static struct bsc_nat *nat; + +static struct bsc_nat *bsc_nat_alloc(void) +{ + struct bsc_nat *nat = talloc_zero(tall_bsc_ctx, struct bsc_nat); + if (!nat) + return NULL; + + INIT_LLIST_HEAD(&nat->sccp_connections); + INIT_LLIST_HEAD(&nat->bsc_connections); + INIT_LLIST_HEAD(&nat->bsc_configs); + return nat; +} + +static struct bsc_connection *bsc_connection_alloc(void) +{ + struct bsc_connection *con = talloc_zero(nat, struct bsc_connection); + if (!con) + return NULL; + + return con; +} + +struct bsc_config *bsc_config_alloc(struct bsc_nat *nat, const char *token, unsigned int lac) +{ + struct bsc_config *conf = talloc_zero(nat, struct bsc_config); + if (!conf) + return NULL; + + conf->token = talloc_strdup(conf, token); + conf->lac = lac; + conf->nr = nat->num_bsc; + conf->nat = nat; + + llist_add(&conf->entry, &nat->bsc_configs); + ++nat->num_bsc; + + return conf; +} + +struct bsc_config *bsc_config_num(struct bsc_nat *nat, int num) +{ + struct bsc_config *conf; + + llist_for_each_entry(conf, &nat->bsc_configs, entry) + if (conf->nr == num) + return conf; + + return NULL; +} + +/* + * below are stubs we need to link + */ +int nm_state_event(enum nm_evt evt, u_int8_t obj_class, void *obj, + struct gsm_nm_state *old_state, struct gsm_nm_state *new_state) +{ + return -1; +} + +void input_event(int event, enum e1inp_sign_type type, struct gsm_bts_trx *trx) +{} + +int gsm0408_rcvmsg(struct msgb *msg, u_int8_t link_id) +{ + return -1; +} + +static int send_reset_ack(struct bsc_fd *bfd) +{ + static const u_int8_t gsm_reset_ack[] = { + 0x00, 0x13, 0xfd, + 0x09, 0x00, 0x03, 0x07, 0x0b, 0x04, 0x43, 0x01, + 0x00, 0xfe, 0x04, 0x43, 0x5c, 0x00, 0xfe, 0x03, + 0x00, 0x01, 0x31, + }; + + return write(bfd->fd, gsm_reset_ack, sizeof(gsm_reset_ack)); +} + +/* + * SCCP patching below + */ + +/* check if we are using this ref for patched already */ +static int sccp_ref_is_free(struct sccp_source_reference *ref) +{ + struct sccp_connections *conn; + + llist_for_each_entry(conn, &nat->sccp_connections, list_entry) { + if (memcmp(ref, &conn->patched_ref, sizeof(*ref)) == 0) + return -1; + } + + return 0; +} + +/* copied from sccp.c */ +static int assign_src_local_reference(struct sccp_source_reference *ref) +{ + static u_int32_t last_ref = 0x50000; + int wrapped = 0; + + do { + struct sccp_source_reference reference; + reference.octet1 = (last_ref >> 0) & 0xff; + reference.octet2 = (last_ref >> 8) & 0xff; + reference.octet3 = (last_ref >> 16) & 0xff; + + ++last_ref; + /* do not use the reversed word and wrap around */ + if ((last_ref & 0x00FFFFFF) == 0x00FFFFFF) { + LOGP(DNAT, LOGL_NOTICE, "Wrapped searching for a free code\n"); + last_ref = 0; + ++wrapped; + } + + if (sccp_ref_is_free(&reference) == 0) { + *ref = reference; + return 0; + } + } while (wrapped != 2); + + LOGP(DNAT, LOGL_ERROR, "Finding a free reference failed\n"); + return -1; +} + +static int create_sccp_src_ref(struct bsc_connection *bsc, struct msgb *msg, struct bsc_nat_parsed *parsed) +{ + struct sccp_connections *conn; + + conn = talloc_zero(nat, struct sccp_connections); + if (!conn) { + LOGP(DNAT, LOGL_ERROR, "Memory allocation failure.\n"); + return -1; + } + + conn->real_ref = *parsed->src_local_ref; + if (assign_src_local_reference(&conn->patched_ref) != 0) { + LOGP(DNAT, LOGL_ERROR, "Failed to assign a ref.\n"); + talloc_free(conn); + return -1; + } + + return 0; +} + +static void remove_sccp_src_ref(struct bsc_connection *bsc, struct msgb *msg, struct bsc_nat_parsed *parsed) +{ + struct sccp_connections *conn; + + llist_for_each_entry(conn, &nat->sccp_connections, list_entry) { + if (memcmp(parsed->src_local_ref, + &conn->real_ref, sizeof(conn->real_ref)) == 0) { + if (bsc != conn->bsc) { + LOGP(DNAT, LOGL_ERROR, "Someone else...\n"); + continue; + } + + + llist_del(&conn->list_entry); + talloc_free(conn); + return; + } + } + + LOGP(DNAT, LOGL_ERROR, "Unknown connection.\n"); +} + +static struct bsc_connection *patch_sccp_src_ref_to_bsc(struct msgb *msg, struct bsc_nat_parsed *parsed) +{ + struct sccp_connections *conn; + llist_for_each_entry(conn, &nat->sccp_connections, list_entry) { + if (memcmp(parsed->dest_local_ref, + &conn->real_ref, sizeof(*parsed->dest_local_ref)) == 0) { + memcpy(parsed->dest_local_ref, + &conn->patched_ref, sizeof(*parsed->dest_local_ref)); + return conn->bsc; + } + } + + return NULL; +} + +static struct bsc_connection *patch_sccp_src_ref_to_msc(struct msgb *msg, struct bsc_nat_parsed *parsed) +{ + struct sccp_connections *conn; + llist_for_each_entry(conn, &nat->sccp_connections, list_entry) { + if (memcmp(parsed->src_local_ref, + &conn->real_ref, sizeof(*parsed->src_local_ref)) == 0) { + memcpy(parsed->src_local_ref, + &conn->patched_ref, sizeof(*parsed->src_local_ref)); + return conn->bsc; + } + } + + return NULL; +} + +/* + * Below is the handling of messages coming + * from the MSC and need to be forwarded to + * a real BSC. + */ +static void initialize_msc_if_needed() +{ + static int init = 0; + init = 1; + + /* do we need to send a GSM 08.08 message here? */ +} + +static int forward_sccp_to_bts(struct msgb *msg) +{ + struct bsc_connection *bsc = NULL; + struct bsc_nat_parsed *parsed; + int rc; + + /* filter, drop, patch the message? */ + parsed = bsc_nat_parse(msg); + if (!parsed) { + LOGP(DNAT, LOGL_ERROR, "Can not parse msg from BSC.\n"); + return -1; + } + + if (bsc_nat_filter_ipa(DIR_BSC, msg, parsed)) + goto exit; + + /* Route and modify the SCCP packet */ + if (parsed->ipa_proto == IPAC_PROTO_SCCP) { + switch (parsed->sccp_type) { + case SCCP_MSG_TYPE_UDT: + /* forward UDT messages to every BSC */ + goto send_to_all; + break; + case SCCP_MSG_TYPE_RLSD: + case SCCP_MSG_TYPE_CREF: + case SCCP_MSG_TYPE_DT1: + case SCCP_MSG_TYPE_CC: + bsc = patch_sccp_src_ref_to_bsc(msg, parsed); + break; + case SCCP_MSG_TYPE_CR: + case SCCP_MSG_TYPE_RLC: + /* MSC never opens a SCCP connection, fall through */ + default: + goto exit; + } + } + + talloc_free(parsed); + if (!bsc) + return -1; + if (!bsc->authenticated) { + LOGP(DNAT, LOGL_ERROR, "Selected BSC not authenticated.\n"); + return -1; + } + + return write(bsc->bsc_fd.fd, msg->data, msg->len); + +send_to_all: + /* + * Filter Paging from the network. We do not want to send a PAGING + * Command to every BSC in our network. We will analys the PAGING + * message and then send it to the authenticated messages... + */ + if (parsed->ipa_proto == IPAC_PROTO_SCCP && parsed->gsm_type == BSS_MAP_MSG_PAGING) { + int data_length; + const u_int8_t *data; + struct tlv_parsed tp; + int i = 0; + + tlv_parse(&tp, gsm0808_att_tlvdef(), msg->l3h + 3, msgb_l3len(msg) - 3, 0, 0); + if (!TLVP_PRESENT(&tp, GSM0808_IE_CELL_IDENTIFIER_LIST)) { + LOGP(DNAT, LOGL_ERROR, "No CellIdentifier List inside paging msg.\n"); + goto exit; + } + + data_length = TLVP_LEN(&tp, GSM0808_IE_CELL_IDENTIFIER_LIST); + data = TLVP_VAL(&tp, GSM0808_IE_CELL_IDENTIFIER_LIST); + if (data[0] != CELL_IDENT_LAC) { + LOGP(DNAT, LOGL_ERROR, "Unhandled cell ident discrminator: %c\n", data[0]); + goto exit; + } + + /* go through each LAC and forward the message */ + for (i = 1; i < data_length - 1; i += 2) { + unsigned int _lac = ntohs(*(unsigned int *) &data[i]); + llist_for_each_entry(bsc, &nat->bsc_connections, list_entry) { + if (!bsc->authenticated || _lac != bsc->lac) + continue; + + rc = write(bsc->bsc_fd.fd, msg->data, msg->len); + if (rc < msg->len) + LOGP(DNAT, LOGL_ERROR, + "Failed to write message to BTS: %d\n", rc); + } + } + + goto exit; + } + /* currently send this to every BSC connected */ + llist_for_each_entry(bsc, &nat->bsc_connections, list_entry) { + if (!bsc->authenticated) + continue; + + rc = write(bsc->bsc_fd.fd, msg->data, msg->len); + + /* try the next one */ + if (rc < msg->len) + LOGP(DNAT, LOGL_ERROR, "Failed to write message to BTS: %d\n", rc); + } + +exit: + talloc_free(parsed); + return 0; +} + +static int ipaccess_msc_cb(struct bsc_fd *bfd, unsigned int what) +{ + int error; + struct msgb *msg = ipaccess_read_msg(bfd, &error); + struct ipaccess_head *hh; + + if (!msg) { + if (error == 0) { + LOGP(DNAT, LOGL_FATAL, "The connection the MSC was lost, exiting\n"); + exit(-2); + } + + LOGP(DNAT, LOGL_ERROR, "Failed to parse ip access message: %d\n", error); + return -1; + } + + LOGP(DNAT, LOGL_DEBUG, "MSG from MSC: %s proto: %d\n", hexdump(msg->data, msg->len), msg->l2h[0]); + + /* handle base message handling */ + hh = (struct ipaccess_head *) msg->data; + ipaccess_rcvmsg_base(msg, bfd); + + /* initialize the networking. This includes sending a GSM08.08 message */ + if (hh->proto == IPAC_PROTO_IPACCESS && msg->l2h[0] == IPAC_MSGT_ID_ACK) + initialize_msc_if_needed(); + else if (hh->proto == IPAC_PROTO_SCCP) + forward_sccp_to_bts(msg); + + msgb_free(msg); + return 0; +} + +/* + * Below is the handling of messages coming + * from the BSC and need to be forwarded to + * a real BSC. + */ + +/* + * Remove the connection from the connections list, + * remove it from the patching of SCCP header lists + * as well. Maybe in the future even close connection.. + */ +static void remove_bsc_connection(struct bsc_connection *connection) +{ + struct sccp_connections *sccp_patch, *tmp; + bsc_unregister_fd(&connection->bsc_fd); + close(connection->bsc_fd.fd); + llist_del(&connection->list_entry); + + /* stop the timeout timer */ + bsc_del_timer(&connection->id_timeout); + + /* remove all SCCP connections */ + llist_for_each_entry_safe(sccp_patch, tmp, &nat->sccp_connections, list_entry) { + if (sccp_patch->bsc != connection) + continue; + + llist_del(&sccp_patch->list_entry); + talloc_free(sccp_patch); + } + + talloc_free(connection); +} + +static void ipaccess_close_bsc(void *data) +{ + struct bsc_connection *conn = data; + + LOGP(DNAT, LOGL_ERROR, "BSC didn't respond to identity request. Closing.\n"); + remove_bsc_connection(conn); +} + +static void ipaccess_auth_bsc(struct tlv_parsed *tvp, struct bsc_connection *bsc) +{ + struct bsc_config *conf; + const char* token = (const char *) TLVP_VAL(tvp, IPAC_IDTAG_UNITNAME); + + llist_for_each_entry(conf, &bsc->nat->bsc_configs, entry) { + if (strcmp(conf->token, token) == 0) { + bsc->authenticated = 1; + bsc->lac = conf->lac; + bsc_del_timer(&bsc->id_timeout); + break; + } + } +} + +static int forward_sccp_to_msc(struct bsc_fd *bfd, struct msgb *msg) +{ + struct bsc_connection *bsc; + struct bsc_connection *found_bsc = NULL; + struct bsc_nat_parsed *parsed; + int rc = -1; + + bsc = bfd->data; + + /* Parse and filter messages */ + parsed = bsc_nat_parse(msg); + if (!parsed) { + LOGP(DNAT, LOGL_ERROR, "Can not parse msg from BSC.\n"); + return -1; + } + + if (bsc_nat_filter_ipa(DIR_MSC, msg, parsed)) + goto exit; + + /* modify the SCCP entries */ + if (parsed->ipa_proto == IPAC_PROTO_SCCP) { + switch (parsed->sccp_type) { + case SCCP_MSG_TYPE_CR: + if (create_sccp_src_ref(bsc, msg, parsed) != 0) + goto exit2; + found_bsc = patch_sccp_src_ref_to_msc(msg, parsed); + break; + case SCCP_MSG_TYPE_RLSD: + case SCCP_MSG_TYPE_CREF: + case SCCP_MSG_TYPE_DT1: + case SCCP_MSG_TYPE_CC: + found_bsc = patch_sccp_src_ref_to_msc(msg, parsed); + break; + case SCCP_MSG_TYPE_RLC: + found_bsc = patch_sccp_src_ref_to_msc(msg, parsed); + remove_sccp_src_ref(bsc, msg, parsed); + break; + case SCCP_MSG_TYPE_UDT: + /* simply forward everything */ + break; + default: + goto exit2; + break; + } + } + + if (found_bsc != bsc) { + LOGP(DNAT, LOGL_ERROR, "Found the wrong entry.\n"); + goto exit2; + } + + if (!bsc->authenticated) { + LOGP(DNAT, LOGL_ERROR, "BSC is not authenticated.\n"); + goto exit2; + } + + /* send the non-filtered but maybe modified msg */ + rc = write(msc_connection.fd, msg->data, msg->len); + talloc_free(parsed); + return rc; + +exit: + /* if we filter out the reset send an ack to the BSC */ + if (parsed->bssap == 0 && parsed->gsm_type == BSS_MAP_MSG_RESET) { + send_reset_ack(bfd); + send_reset_ack(bfd); + } else if (parsed->ipa_proto == IPAC_PROTO_IPACCESS) { + /* do we know who is handling this? */ + if (msg->l2h[0] == IPAC_MSGT_ID_RESP) { + struct tlv_parsed tvp; + ipaccess_idtag_parse(&tvp, + (unsigned char *) msg->l2h + 2, + msgb_l2len(msg) - 2); + if (TLVP_PRESENT(&tvp, IPAC_IDTAG_UNITNAME)) + ipaccess_auth_bsc(&tvp, bsc); + } + + goto exit2; + } + +exit2: + talloc_free(parsed); + return rc; +} + +static int ipaccess_bsc_cb(struct bsc_fd *bfd, unsigned int what) +{ + int error; + struct msgb *msg = ipaccess_read_msg(bfd, &error); + + if (!msg) { + if (error == 0) { + LOGP(DNAT, LOGL_ERROR, "The connection to the BSC was lost. Cleaning it\n"); + remove_bsc_connection((struct bsc_connection *) bfd->data); + } else { + LOGP(DNAT, LOGL_ERROR, "Failed to parse ip access message: %d\n", error); + } + return -1; + } + + + LOGP(DNAT, LOGL_DEBUG, "MSG from BSC: %s proto: %d\n", hexdump(msg->data, msg->len), msg->l2h[0]); + + /* Handle messages from the BSC */ + /* FIXME: Currently no PONG is sent to the BSC */ + /* FIXME: Currently no ID ACK is sent to the BSC */ + forward_sccp_to_msc(bfd, msg); + msgb_free(msg); + + return 0; +} + +static int ipaccess_listen_bsc_cb(struct bsc_fd *bfd, unsigned int what) +{ + struct bsc_connection *bsc; + int ret; + struct sockaddr_in sa; + socklen_t sa_len = sizeof(sa); + + if (!(what & BSC_FD_READ)) + return 0; + + ret = accept(bfd->fd, (struct sockaddr *) &sa, &sa_len); + if (ret < 0) { + perror("accept"); + return ret; + } + + /* todo... do something with the connection */ + /* todo... use GNUtls to see if we want to trust this as a BTS */ + + /* + * + */ + bsc = bsc_connection_alloc(); + if (!bsc) { + LOGP(DNAT, LOGL_ERROR, "Failed to allocate BSC struct.\n"); + close(ret); + return -1; + } + + bsc->nat = nat; + bsc->bsc_fd.data = bsc; + bsc->bsc_fd.fd = ret; + bsc->bsc_fd.cb = ipaccess_bsc_cb; + bsc->bsc_fd.when = BSC_FD_READ; + if (bsc_register_fd(&bsc->bsc_fd) < 0) { + LOGP(DNAT, LOGL_ERROR, "Failed to register BSC fd.\n"); + close(ret); + talloc_free(bsc); + return -2; + } + + LOGP(DNAT, LOGL_INFO, "Registered new BSC\n"); + llist_add(&bsc->list_entry, &nat->bsc_connections); + ipaccess_send_id_ack(bsc->bsc_fd.fd); + ipaccess_send_id_req(ret); + + /* + * start the hangup timer + */ + bsc->id_timeout.data = bsc; + bsc->id_timeout.cb = ipaccess_close_bsc; + bsc_schedule_timer(&bsc->id_timeout, 2, 0); + return 0; +} + +static int listen_for_bsc(struct bsc_fd *bfd, struct in_addr *in_addr, int port) +{ + struct sockaddr_in addr; + int ret, on = 1; + + bfd->fd = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP); + bfd->cb = ipaccess_listen_bsc_cb; + bfd->when = BSC_FD_READ; + + memset(&addr, 0, sizeof(addr)); + addr.sin_family = AF_INET; + addr.sin_port = htons(port); + addr.sin_addr.s_addr = in_addr->s_addr; + + setsockopt(bfd->fd, SOL_SOCKET, SO_REUSEADDR, &on, sizeof(on)); + + ret = bind(bfd->fd, (struct sockaddr *) &addr, sizeof(addr)); + if (ret < 0) { + fprintf(stderr, "Could not bind the BSC socket %s\n", + strerror(errno)); + return -EIO; + } + + ret = listen(bfd->fd, 1); + if (ret < 0) { + perror("listen"); + return ret; + } + + ret = bsc_register_fd(bfd); + if (ret < 0) { + perror("register_listen_fd"); + return ret; + } + return 0; +} + +static void print_usage() +{ + printf("Usage: bsc_nat\n"); +} + +static void print_help() +{ + printf(" Some useful help...\n"); + printf(" -h --help this text\n"); + printf(" -d option --debug=DRLL:DCC:DMM:DRR:DRSL:DNM enable debugging\n"); + printf(" -s --disable-color\n"); + printf(" -c --config-file filename The config file to use.\n"); + printf(" -m --msc=IP. The address of the MSC.\n"); + printf(" -l --local=IP. The local address of this BSC.\n"); +} + +static void handle_options(int argc, char** argv) +{ + while (1) { + int option_index = 0, c; + static struct option long_options[] = { + {"help", 0, 0, 'h'}, + {"debug", 1, 0, 'd'}, + {"config-file", 1, 0, 'c'}, + {"disable-color", 0, 0, 's'}, + {"timestamp", 0, 0, 'T'}, + {"msc", 1, 0, 'm'}, + {"local", 1, 0, 'l'}, + {0, 0, 0, 0} + }; + + c = getopt_long(argc, argv, "hd:sTPc:m:l:", + long_options, &option_index); + if (c == -1) + break; + + switch (c) { + case 'h': + print_usage(); + print_help(); + exit(0); + case 's': + debug_set_use_color(stderr_target, 0); + break; + case 'd': + debug_parse_category_mask(stderr_target, optarg); + break; + case 'c': + config_file = strdup(optarg); + break; + case 'T': + debug_set_print_timestamp(stderr_target, 1); + break; + case 'm': + msc_address = strdup(optarg); + break; + case 'l': + inet_aton(optarg, &local_addr); + break; + default: + /* ignore */ + break; + } + } +} + +static void signal_handler(int signal) +{ + switch (signal) { + case SIGABRT: + /* in case of abort, we want to obtain a talloc report + * and then return to the caller, who will abort the process */ + case SIGUSR1: + talloc_report_full(tall_bsc_ctx, stderr); + break; + default: + break; + } +} + +int main(int argc, char** argv) +{ + int rc; + + debug_init(); + stderr_target = debug_target_create_stderr(); + debug_add_target(stderr_target); + debug_set_all_filter(stderr_target, 1); + + /* parse options */ + local_addr.s_addr = INADDR_ANY; + handle_options(argc, argv); + + nat = bsc_nat_alloc(); + if (!nat) { + fprintf(stderr, "Failed to allocate the BSC nat.\n"); + return -4; + } + + /* init vty and parse */ + bsc_nat_vty_init(nat); + telnet_init(NULL, 4244); + if (vty_read_config_file(config_file) < 0) { + fprintf(stderr, "Failed to parse the config file: '%s'\n", config_file); + return -3; + } + + /* seed the PRNG */ + srand(time(NULL)); + + /* connect to the MSC */ + msc_connection.cb = ipaccess_msc_cb; + rc = connect_to_msc(&msc_connection, msc_address, 5000); + if (rc < 0) { + fprintf(stderr, "Opening the MSC connection failed.\n"); + exit(1); + } + + /* wait for the BSC */ + if (listen_for_bsc(&bsc_connection, &local_addr, 5000) < 0) { + fprintf(stderr, "Failed to listen for BSC.\n"); + exit(1); + } + + signal(SIGABRT, &signal_handler); + signal(SIGUSR1, &signal_handler); + signal(SIGPIPE, SIG_IGN); + + while (1) { + bsc_select_main(0); + } + + return 0; +} |