cel_tds.c

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/*
 * Asterisk -- An open source telephony toolkit.
 *
 * Copyright (C) 2008, Digium, Inc.
 *
 * See http://www.asterisk.org for more information about
 * the Asterisk project. Please do not directly contact
 * any of the maintainers of this project for assistance;
 * the project provides a web site, mailing lists and IRC
 * channels for your use.
 *
 * This program is free software, distributed under the terms of
 * the GNU General Public License Version 2. See the LICENSE file
 * at the top of the source tree.
 */
 
/*! \file
 *
 * \brief FreeTDS CEL logger
 * http://www.freetds.org/
 * \ingroup cel_drivers
 */
 
/*! \verbatim
 *
 * Table Structure for `cel`
 *
 
CREATE TABLE [dbo].[cel] (
    [accountcode] [varchar] (20) NULL ,
    [cidname] [varchar] (80) NULL ,
    [cidnum] [varchar] (80) NULL ,
    [cidani] [varchar] (80) NULL ,
    [cidrdnis] [varchar] (80) NULL ,
    [ciddnid] [varchar] (80) NULL ,
    [exten] [varchar] (80) NULL ,
    [context] [varchar] (80) NULL ,
    [channame] [varchar] (80) NULL ,
    [appname] [varchar] (80) NULL ,
    [appdata] [varchar] (80) NULL ,
    [eventtime] [datetime] NULL ,
    [eventtype] [varchar] (32) NULL ,
    [uniqueid] [varchar] (32) NULL ,
    [linkedid] [varchar] (32) NULL ,
    [amaflags] [varchar] (16) NULL ,
    [userfield] [varchar] (32) NULL ,
    [peer] [varchar] (32) NULL
) ON [PRIMARY]
 
\endverbatim
 
*/
 
/*** MODULEINFO
    <depend>freetds</depend>
    <support_level>extended</support_level>
 ***/
 
#include "asterisk.h"
 
#include <time.h>
#include <math.h>
 
#include "asterisk/config.h"
#include "asterisk/channel.h"
#include "asterisk/cel.h"
#include "asterisk/module.h"
#include "asterisk/logger.h"
 
#include <sqlfront.h>
#include <sybdb.h>
 
#ifdef FREETDS_PRE_0_62
#warning "You have older TDS, you should upgrade!"
#endif
 
#define DATE_FORMAT "%Y/%m/%d %T"
 
#define TDS_BACKEND_NAME "CEL TDS logging backend"
 
static char *config = "cel_tds.conf";
 
struct cel_tds_config {
    AST_DECLARE_STRING_FIELDS(
        AST_STRING_FIELD(connection);
        AST_STRING_FIELD(database);
        AST_STRING_FIELD(username);
        AST_STRING_FIELD(password);
        AST_STRING_FIELD(table);
        AST_STRING_FIELD(charset);
        AST_STRING_FIELD(language);
    );
    DBPROCESS *dbproc;
    unsigned int connected:1;
};
 
AST_MUTEX_DEFINE_STATIC(tds_lock);
 
static struct cel_tds_config *settings;
 
static char *anti_injection(const char *, int);
static void get_date(char *, size_t len, struct timeval);
 
static int execute_and_consume(DBPROCESS *dbproc, const char *fmt, ...)
    __attribute__((format(printf, 2, 3)));
 
static int mssql_connect(void);
static int mssql_disconnect(void);
 
static void tds_log(struct ast_event *event)
{
    char start[80];
    char *accountcode_ai, *clidnum_ai, *exten_ai, *context_ai, *clid_ai, *channel_ai, *app_ai, *appdata_ai, *uniqueid_ai, *linkedid_ai, *cidani_ai, *cidrdnis_ai, *ciddnid_ai, *peer_ai, *userfield_ai;
    RETCODE erc;
    int attempt = 1;
    struct ast_cel_event_record record = {
        .version = AST_CEL_EVENT_RECORD_VERSION,
    };
 
    if (ast_cel_fill_record(event, &record)) {
        return;
    }
 
    ast_mutex_lock(&tds_lock);
 
    accountcode_ai = anti_injection(record.account_code, 20);
    clidnum_ai     = anti_injection(record.caller_id_num, 80);
    clid_ai        = anti_injection(record.caller_id_name, 80);
    cidani_ai      = anti_injection(record.caller_id_ani, 80);
    cidrdnis_ai    = anti_injection(record.caller_id_rdnis, 80);
    ciddnid_ai     = anti_injection(record.caller_id_dnid, 80);
    exten_ai       = anti_injection(record.extension, 80);
    context_ai     = anti_injection(record.context, 80);
    channel_ai     = anti_injection(record.channel_name, 80);
    app_ai         = anti_injection(record.application_name, 80);
    appdata_ai     = anti_injection(record.application_data, 80);
    uniqueid_ai    = anti_injection(record.unique_id, 32);
    linkedid_ai    = anti_injection(record.linked_id, 32);
    userfield_ai   = anti_injection(record.user_field, 32);
    peer_ai        = anti_injection(record.peer, 32);
 
    get_date(start, sizeof(start), record.event_time);
 
retry:
    /* Ensure that we are connected */
    if (!settings->connected) {
        ast_log(LOG_NOTICE, "Attempting to reconnect to %s (Attempt %d)\n", settings->connection, attempt);
        if (mssql_connect()) {
            /* Connect failed */
            if (attempt++ < 3) {
                goto retry;
            }
            goto done;
        }
    }
 
    erc = dbfcmd(settings->dbproc,
        "INSERT INTO %s "
        "("
        "accountcode,"
        "cidnum,"
        "cidname,"
        "cidani,"
        "cidrdnis,"
        "ciddnid,"
        "exten,"
        "context,"
        "channel,"
        "appname,"
        "appdata,"
        "eventtime,"
        "eventtype,"
        "amaflags, "
        "uniqueid,"
        "linkedid,"
        "userfield,"
        "peer"
        ") "
        "VALUES "
        "("
        "'%s'," /* accountcode */
        "'%s'," /* clidnum */
        "'%s'," /* clid */
        "'%s'," /* cid-ani */
        "'%s'," /* cid-rdnis */
        "'%s'," /* cid-dnid */
        "'%s'," /* exten */
        "'%s'," /* context */
        "'%s'," /* channel */
        "'%s'," /* app */
        "'%s'," /* appdata */
        "%s, "  /* eventtime */
        "'%s'," /* eventtype */
        "'%s'," /* amaflags */
        "'%s'," /* uniqueid */
        "'%s'," /* linkedid */
        "'%s'," /* userfield */
        "'%s'"  /* peer */
        ")",
        settings->table, accountcode_ai, clidnum_ai, clid_ai, cidani_ai, cidrdnis_ai,
        ciddnid_ai, exten_ai, context_ai, channel_ai, app_ai, appdata_ai, start,
        (record.event_type == AST_CEL_USER_DEFINED)
            ? record.user_defined_name : record.event_name,
                    ast_channel_amaflags2string(record.amaflag), uniqueid_ai, linkedid_ai,
        userfield_ai, peer_ai);
 
    if (erc == FAIL) {
        if (attempt++ < 3) {
            ast_log(LOG_NOTICE, "Failed to build INSERT statement, retrying...\n");
            mssql_disconnect();
            goto retry;
        } else {
            ast_log(LOG_ERROR, "Failed to build INSERT statement, no CEL was logged.\n");
            goto done;
        }
    }
 
    if (dbsqlexec(settings->dbproc) == FAIL) {
        if (attempt++ < 3) {
            ast_log(LOG_NOTICE, "Failed to execute INSERT statement, retrying...\n");
            mssql_disconnect();
            goto retry;
        } else {
            ast_log(LOG_ERROR, "Failed to execute INSERT statement, no CEL was logged.\n");
            goto done;
        }
    }
 
    /* Consume any results we might get back (this is more of a sanity check than
     * anything else, since an INSERT shouldn't return results). */
    while (dbresults(settings->dbproc) != NO_MORE_RESULTS) {
        while (dbnextrow(settings->dbproc) != NO_MORE_ROWS);
    }
 
done:
    ast_mutex_unlock(&tds_lock);
 
    ast_free(accountcode_ai);
    ast_free(clidnum_ai);
    ast_free(clid_ai);
    ast_free(cidani_ai);
    ast_free(cidrdnis_ai);
    ast_free(ciddnid_ai);
    ast_free(exten_ai);
    ast_free(context_ai);
    ast_free(channel_ai);
    ast_free(app_ai);
    ast_free(appdata_ai);
    ast_free(uniqueid_ai);
    ast_free(linkedid_ai);
    ast_free(userfield_ai);
    ast_free(peer_ai);
 
    return;
}
 
static char *anti_injection(const char *str, int len)
{
    /* Reference to http://www.nextgenss.com/papers/advanced_sql_injection.pdf */
    char *buf;
    char *buf_ptr, *srh_ptr;
    char *known_bad[] = {"select", "insert", "update", "delete", "drop", ";", "--", "\0"};
    int idx;
 
    if (!(buf = ast_calloc(1, len + 1))) {
        ast_log(LOG_ERROR, "Out of memory\n");
        return NULL;
    }
 
    buf_ptr = buf;
 
    /* Escape single quotes */
    for (; *str && strlen(buf) < len; str++) {
        if (*str == '\'') {
            *buf_ptr++ = '\'';
        }
        *buf_ptr++ = *str;
    }
    *buf_ptr = '\0';
 
    /* Erase known bad input */
    for (idx = 0; *known_bad[idx]; idx++) {
        while ((srh_ptr = strcasestr(buf, known_bad[idx]))) {
            memmove(srh_ptr, srh_ptr + strlen(known_bad[idx]), strlen(srh_ptr + strlen(known_bad[idx])) + 1);
        }
    }
    return buf;
}
 
static void get_date(char *dateField, size_t len, struct timeval when)
{
    /* To make sure we have date variable if not insert null to SQL */
    if (!ast_tvzero(when)) {
        struct ast_tm tm;
        ast_localtime(&when, &tm, NULL);
        ast_strftime(dateField, len, "'" DATE_FORMAT "'", &tm);
    } else {
        ast_copy_string(dateField, "null", len);
    }
}
 
static int execute_and_consume(DBPROCESS *dbproc, const char *fmt, ...)
{
    va_list ap;
    char *buffer;
 
    va_start(ap, fmt);
    if (ast_vasprintf(&buffer, fmt, ap) < 0) {
        va_end(ap);
        return 1;
    }
    va_end(ap);
 
    if (dbfcmd(dbproc, buffer) == FAIL) {
        ast_free(buffer);
        return 1;
    }
 
    ast_free(buffer);
 
    if (dbsqlexec(dbproc) == FAIL) {
        return 1;
    }
 
    /* Consume the result set (we don't really care about the result, though) */
    while (dbresults(dbproc) != NO_MORE_RESULTS) {
        while (dbnextrow(dbproc) != NO_MORE_ROWS);
    }
 
    return 0;
}
 
static int mssql_disconnect(void)
{
    if (settings->dbproc) {
        dbclose(settings->dbproc);
        settings->dbproc = NULL;
    }
    settings->connected = 0;
 
    return 0;
}
 
static int mssql_connect(void)
{
    LOGINREC *login;
 
    if ((login = dblogin()) == NULL) {
        ast_log(LOG_ERROR, "Unable to allocate login structure for db-lib\n");
        return -1;
    }
 
    DBSETLAPP(login,  "TSQL");
    DBSETLUSER(login, (char *) settings->username);
    DBSETLPWD(login,  (char *) settings->password);
 
    if (!ast_strlen_zero(settings->charset)) {
        DBSETLCHARSET(login, (char *) settings->charset);
    }
 
    if (!ast_strlen_zero(settings->language)) {
        DBSETLNATLANG(login, (char *) settings->language);
    }
 
    if ((settings->dbproc = dbopen(login, (char *) settings->connection)) == NULL) {
        ast_log(LOG_ERROR, "Unable to connect to %s\n", settings->connection);
        dbloginfree(login);
        return -1;
    }
 
    dbloginfree(login);
 
    if (dbuse(settings->dbproc, (char *) settings->database) == FAIL) {
        ast_log(LOG_ERROR, "Unable to select database %s\n", settings->database);
        goto failed;
    }
 
    if (execute_and_consume(settings->dbproc, "SELECT 1 FROM [%s]", settings->table)) {
        ast_log(LOG_ERROR, "Unable to find table '%s'\n", settings->table);
        goto failed;
    }
 
    settings->connected = 1;
 
    return 0;
 
failed:
    dbclose(settings->dbproc);
    settings->dbproc = NULL;
    return -1;
}
 
static int tds_unload_module(void)
{
    ast_cel_backend_unregister(TDS_BACKEND_NAME);
 
    if (settings) {
        ast_mutex_lock(&tds_lock);
        mssql_disconnect();
        ast_mutex_unlock(&tds_lock);
 
        ast_string_field_free_memory(settings);
        ast_free(settings);
    }
 
    dbexit();
 
    return 0;
}
 
static int tds_error_handler(DBPROCESS *dbproc, int severity, int dberr, int oserr, char *dberrstr, char *oserrstr)
{
    ast_log(LOG_ERROR, "%s (%d)\n", dberrstr, dberr);
 
    if (oserr != DBNOERR) {
        ast_log(LOG_ERROR, "%s (%d)\n", oserrstr, oserr);
    }
 
    return INT_CANCEL;
}
 
static int tds_message_handler(DBPROCESS *dbproc, DBINT msgno, int msgstate, int severity, char *msgtext, char *srvname, char *procname, int line)
{
    ast_debug(1, "Msg %d, Level %d, State %d, Line %d\n", msgno, severity, msgstate, line);
    ast_log(LOG_NOTICE, "%s\n", msgtext);
 
    return 0;
}
 
static int tds_load_module(int reload)
{
    struct ast_config *cfg;
    const char *ptr = NULL;
    struct ast_flags config_flags = { reload ? CONFIG_FLAG_FILEUNCHANGED : 0 };
 
    cfg = ast_config_load(config, config_flags);
    if (!cfg || cfg == CONFIG_STATUS_FILEINVALID) {
        ast_log(LOG_NOTICE, "Unable to load TDS config for CELs: %s\n", config);
        return 0;
    } else if (cfg == CONFIG_STATUS_FILEUNCHANGED) {
        return 0;
    }
 
    if (!ast_variable_browse(cfg, "global")) {
        /* nothing configured */
        ast_config_destroy(cfg);
        ast_log(LOG_NOTICE, "cel_tds has no global category, nothing to configure.\n");
        return 0;
    }
 
    ast_mutex_lock(&tds_lock);
 
    /* Clear out any existing settings */
    ast_string_field_init(settings, 0);
 
    ptr = ast_variable_retrieve(cfg, "global", "connection");
    if (ptr) {
        ast_string_field_set(settings, connection, ptr);
    } else {
        ast_log(LOG_ERROR, "Failed to connect: Database connection name not specified.\n");
        goto failed;
    }
 
    ptr = ast_variable_retrieve(cfg, "global", "dbname");
    if (ptr) {
        ast_string_field_set(settings, database, ptr);
    } else {
        ast_log(LOG_ERROR, "Failed to connect: Database dbname not specified.\n");
        goto failed;
    }
 
    ptr = ast_variable_retrieve(cfg, "global", "user");
    if (ptr) {
        ast_string_field_set(settings, username, ptr);
    } else {
        ast_log(LOG_ERROR, "Failed to connect: Database dbuser not specified.\n");
        goto failed;
    }
 
    ptr = ast_variable_retrieve(cfg, "global", "password");
    if (ptr) {
        ast_string_field_set(settings, password, ptr);
    } else {
        ast_log(LOG_ERROR, "Failed to connect: Database password not specified.\n");
        goto failed;
    }
 
    ptr = ast_variable_retrieve(cfg, "global", "charset");
    if (ptr) {
        ast_string_field_set(settings, charset, ptr);
    }
 
    ptr = ast_variable_retrieve(cfg, "global", "language");
    if (ptr) {
        ast_string_field_set(settings, language, ptr);
    }
 
    ptr = ast_variable_retrieve(cfg, "global", "table");
    if (ptr) {
        ast_string_field_set(settings, table, ptr);
    } else {
        ast_log(LOG_NOTICE, "Table name not specified, using 'cel' by default.\n");
        ast_string_field_set(settings, table, "cel");
    }
 
    mssql_disconnect();
 
    if (mssql_connect()) {
        /* We failed to connect (mssql_connect takes care of logging it) */
        goto failed;
    }
 
    ast_mutex_unlock(&tds_lock);
    ast_config_destroy(cfg);
 
    return 1;
 
failed:
    ast_mutex_unlock(&tds_lock);
    ast_config_destroy(cfg);
 
    return 0;
}
 
static int reload(void)
{
    return tds_load_module(1);
}
 
static int load_module(void)
{
    if (dbinit() == FAIL) {
        ast_log(LOG_ERROR, "Failed to initialize FreeTDS db-lib\n");
        return AST_MODULE_LOAD_DECLINE;
    }
 
    dberrhandle(tds_error_handler);
    dbmsghandle(tds_message_handler);
 
    settings = ast_calloc_with_stringfields(1, struct cel_tds_config, 256);
 
    if (!settings) {
        dbexit();
        return AST_MODULE_LOAD_DECLINE;
    }
 
    if (!tds_load_module(0)) {
        ast_string_field_free_memory(settings);
        ast_free(settings);
        settings = NULL;
        dbexit();
        ast_log(LOG_WARNING,"cel_tds module had config problems; declining load\n");
        return AST_MODULE_LOAD_DECLINE;
    }
 
    /* Register MSSQL CEL handler */
    if (ast_cel_backend_register(TDS_BACKEND_NAME, tds_log)) {
        ast_log(LOG_ERROR, "Unable to register MSSQL CEL handling\n");
        ast_string_field_free_memory(settings);
        ast_free(settings);
        settings = NULL;
        dbexit();
        return AST_MODULE_LOAD_DECLINE;
    }
 
    return AST_MODULE_LOAD_SUCCESS;
}
 
static int unload_module(void)
{
    return tds_unload_module();
}
 
AST_MODULE_INFO(ASTERISK_GPL_KEY, AST_MODFLAG_LOAD_ORDER, "FreeTDS CEL Backend",
    .support_level = AST_MODULE_SUPPORT_EXTENDED,
    .load = load_module,
    .unload = unload_module,
    .reload = reload,
    .load_pri = AST_MODPRI_CDR_DRIVER,
    .requires = "cel",
);