test_dns_recurring.c

Go to the documentation of this file.

/*
 * Asterisk -- An open source telephony toolkit.
 *
 * Copyright (C) 2015, Mark Michelson
 *
 * Mark Michelson <mmichelson@digium.com>
 *
 * 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.
 */
 
/*** MODULEINFO
    <depend>TEST_FRAMEWORK</depend>
    <support_level>core</support_level>
 ***/
 
#include "asterisk.h"
 
#include <arpa/nameser.h>
#include <arpa/inet.h>
 
#include "asterisk/test.h"
#include "asterisk/module.h"
#include "asterisk/dns_core.h"
#include "asterisk/dns_resolver.h"
#include "asterisk/dns_recurring.h"
#include "asterisk/dns_internal.h"
 
struct recurring_data {
    /*! TTL to place in first returned result */
    int ttl1;
    /*! TTL to place in second returned result */
    int ttl2;
    /*! Boolean indicator if query has completed */
    int query_complete;
    /*! Number of times recurring resolution has completed */
    int complete_resolutions;
    /*! Number of times resolve() method has been called */
    int resolves;
    /*! Indicates that the query is expected to be canceled */
    int cancel_expected;
    /*! Indicates that the query is ready to be canceled */
    int cancel_ready;
    /*! Indicates that the query has been canceled */
    int canceled;
    ast_mutex_t lock;
    ast_cond_t cond;
};
 
static void recurring_data_destructor(void *obj)
{
    struct recurring_data *rdata = obj;
 
    ast_mutex_destroy(&rdata->lock);
    ast_cond_destroy(&rdata->cond);
}
 
static struct recurring_data *recurring_data_alloc(void)
{
    struct recurring_data *rdata;
 
    rdata = ao2_alloc(sizeof(*rdata), recurring_data_destructor);
    if (!rdata) {
        return NULL;
    }
 
    ast_mutex_init(&rdata->lock);
    ast_cond_init(&rdata->cond, NULL);
 
    return rdata;
}
 
#define DNS_ANSWER "Yes sirree"
#define DNS_ANSWER_SIZE strlen(DNS_ANSWER)
 
/*!
 * \brief Thread that performs asynchronous resolution.
 *
 * This thread uses the query's user data to determine how to
 * perform the resolution. The query may either be canceled or
 * it may be completed with records.
 *
 * \param dns_query The ast_dns_query that is being performed
 * \return NULL
 */
static void *resolution_thread(void *dns_query)
{
    struct ast_dns_query *query = dns_query;
 
    static const char *ADDR1 = "127.0.0.1";
    static const size_t ADDR1_BUFSIZE = sizeof(struct in_addr);
    char addr1_buf[ADDR1_BUFSIZE];
 
    static const char *ADDR2 = "192.168.0.1";
    static const size_t ADDR2_BUFSIZE = sizeof(struct in_addr);
    char addr2_buf[ADDR2_BUFSIZE];
 
    struct ast_dns_query_recurring *recurring = ast_dns_query_get_data(query);
    struct recurring_data *rdata = recurring->user_data;
 
    ast_assert(rdata != NULL);
 
    /* Canceling is an interesting dance. This thread needs to signal that it is
     * ready to be canceled. Then it needs to wait until the query is actually canceled.
     */
    if (rdata->cancel_expected) {
        ast_mutex_lock(&rdata->lock);
        rdata->cancel_ready = 1;
        ast_cond_signal(&rdata->cond);
 
        while (!rdata->canceled) {
            ast_cond_wait(&rdata->cond, &rdata->lock);
        }
        ast_mutex_unlock(&rdata->lock);
 
        ast_dns_resolver_completed(query);
        ao2_ref(query, -1);
 
        return NULL;
    }
 
    /* When the query isn't canceled, we set the TTL of the results based on what
     * we've been told to set it to
     */
    ast_dns_resolver_set_result(query, 0, 0, NOERROR, "asterisk.org", DNS_ANSWER, DNS_ANSWER_SIZE);
 
    inet_pton(AF_INET, ADDR1, addr1_buf);
    ast_dns_resolver_add_record(query, T_A, C_IN, rdata->ttl1, addr1_buf, ADDR1_BUFSIZE);
 
    inet_pton(AF_INET, ADDR2, addr2_buf);
    ast_dns_resolver_add_record(query, T_A, C_IN, rdata->ttl2, addr2_buf, ADDR2_BUFSIZE);
 
    ++rdata->complete_resolutions;
 
    ast_dns_resolver_completed(query);
 
    ao2_ref(query, -1);
    return NULL;
}
 
/*!
 * \brief Resolver's resolve() method
 *
 * \param query The query that is to be resolved
 * \retval 0 Successfully created thread to perform the resolution
 * \retval non-zero Failed to create resolution thread
 */
static int recurring_resolve(struct ast_dns_query *query)
{
    struct ast_dns_query_recurring *recurring = ast_dns_query_get_data(query);
    struct recurring_data *rdata = recurring->user_data;
    pthread_t resolver_thread;
 
    ast_assert(rdata != NULL);
    ++rdata->resolves;
    return ast_pthread_create_detached(&resolver_thread, NULL, resolution_thread, ao2_bump(query));
}
 
/*!
 * \brief Resolver's cancel() method
 *
 * \param query The query to cancel
 * \return 0
 */
static int recurring_cancel(struct ast_dns_query *query)
{
    struct ast_dns_query_recurring *recurring = ast_dns_query_get_data(query);
    struct recurring_data *rdata = recurring->user_data;
 
    ast_mutex_lock(&rdata->lock);
    rdata->canceled = 1;
    ast_cond_signal(&rdata->cond);
    ast_mutex_unlock(&rdata->lock);
 
    return 0;
}
 
static struct ast_dns_resolver recurring_resolver = {
    .name = "test_recurring",
    .priority = 0,
    .resolve = recurring_resolve,
    .cancel = recurring_cancel,
};
 
/*!
 * \brief Wait for a successful resolution to complete
 *
 * This is called whenever a successful DNS resolution occurs. This function
 * serves to ensure that parameters are as we expect them to be.
 *
 * \param test The test being executed
 * \param rdata DNS query user data
 * \param expected_lapse The amount of time we expect to wait for the query to complete
 * \param num_resolves The number of DNS resolutions that have been executed
 * \param num_completed The number of DNS resolutions we expect to have completed successfully
 * \param canceled Whether the query is expected to have been canceled
 */
static int wait_for_resolution(struct ast_test *test, struct recurring_data *rdata,
        int expected_lapse, int num_resolves, int num_completed, int canceled)
{
    struct timespec begin;
    struct timespec end;
    struct timespec timeout;
    int secdiff;
 
    begin = ast_tsnow();
 
    timeout.tv_sec = begin.tv_sec + 20;
    timeout.tv_nsec = begin.tv_nsec;
 
    ast_mutex_lock(&rdata->lock);
    while (!rdata->query_complete) {
        if (ast_cond_timedwait(&rdata->cond, &rdata->lock, &timeout) == ETIMEDOUT) {
            break;
        }
    }
    ast_mutex_unlock(&rdata->lock);
 
    if (!rdata->query_complete) {
        ast_test_status_update(test, "Query timed out\n");
        return -1;
    }
 
    rdata->query_complete = 0;
    end = ast_tsnow();
 
    secdiff = end.tv_sec - begin.tv_sec;
 
    /* Give ourselves some wiggle room */
    if (secdiff < expected_lapse - 2 || secdiff > expected_lapse + 2) {
        ast_test_status_update(test, "Query did not complete in expected time\n");
        return -1;
    }
 
    if (rdata->resolves != num_resolves || rdata->complete_resolutions != num_completed) {
        ast_test_status_update(test, "Query has not undergone expected number of resolutions\n");
        return -1;
    }
 
    if (rdata->canceled != canceled) {
        ast_test_status_update(test, "Query was canceled unexpectedly\n");
        return -1;
    }
 
    ast_test_status_update(test, "Query completed in expected time frame\n");
 
    return 0;
}
 
static void async_callback(const struct ast_dns_query *query)
{
    struct recurring_data *rdata = ast_dns_query_get_data(query);
 
    ast_assert(rdata != NULL);
 
    ast_mutex_lock(&rdata->lock);
    rdata->query_complete = 1;
    ast_cond_signal(&rdata->cond);
    ast_mutex_unlock(&rdata->lock);
}
 
AST_TEST_DEFINE(recurring_query)
{
    RAII_VAR(struct ast_dns_query_recurring *, recurring_query, NULL, ao2_cleanup);
    RAII_VAR(struct recurring_data *, rdata, NULL, ao2_cleanup);
 
    enum ast_test_result_state res = AST_TEST_PASS;
    int expected_lapse;
 
    switch (cmd) {
    case TEST_INIT:
        info->name = "recurring_query";
        info->category = "/main/dns/recurring/";
        info->summary = "Test nominal asynchronous recurring DNS queries";
        info->description =
            "This tests nominal recurring queries in the following ways:\n"
            "\t* An asynchronous query is sent to a mock resolver\n"
            "\t* The mock resolver returns two records with different TTLs\n"
            "\t* We ensure that the query re-occurs according to the lower of the TTLs\n"
            "\t* The mock resolver returns two records, this time with different TTLs\n"
            "\t  from the first time the query was resolved\n"
            "\t* We ensure that the query re-occurs according to the new lower TTL";
        return AST_TEST_NOT_RUN;
    case TEST_EXECUTE:
        break;
    }
 
    if (ast_dns_resolver_register(&recurring_resolver)) {
        ast_test_status_update(test, "Failed to register recurring DNS resolver\n");
        return AST_TEST_FAIL;
    }
 
    rdata = recurring_data_alloc();
    if (!rdata) {
        ast_test_status_update(test, "Failed to allocate data necessary for recurring test\n");
        res = AST_TEST_FAIL;
        goto cleanup;
    }
 
    expected_lapse = 0;
    rdata->ttl1 = 5;
    rdata->ttl2 = 20;
 
    recurring_query = ast_dns_resolve_recurring("asterisk.org", T_A, C_IN, async_callback, rdata);
    if (!recurring_query) {
        ast_test_status_update(test, "Failed to create recurring DNS query\n");
        res = AST_TEST_FAIL;
        goto cleanup;
    }
 
    /* This should be near instantaneous */
    if (wait_for_resolution(test, rdata, expected_lapse, 1, 1, 0)) {
        res = AST_TEST_FAIL;
        goto cleanup;
    }
 
    expected_lapse = rdata->ttl1;
    rdata->ttl1 = 45;
    rdata->ttl2 = 10;
 
    /* This should take approximately 5 seconds */
    if (wait_for_resolution(test, rdata, expected_lapse, 2, 2, 0)) {
        res = AST_TEST_FAIL;
        goto cleanup;
    }
 
    expected_lapse = rdata->ttl2;
 
    /* This should take approximately 10 seconds */
    if (wait_for_resolution(test, rdata, expected_lapse, 3, 3, 0)) {
        res = AST_TEST_FAIL;
        goto cleanup;
    }
 
cleanup:
    if (recurring_query) {
        /* XXX I don't like calling this here since I'm not testing
         * canceling recurring queries, but I'm forced into it here
         */
        ast_dns_resolve_recurring_cancel(recurring_query);
    }
    ast_dns_resolver_unregister(&recurring_resolver);
    return res;
}
 
static int fail_resolve(struct ast_dns_query *query)
{
    return -1;
}
 
static int stub_cancel(struct ast_dns_query *query)
{
    return 0;
}
 
static void stub_callback(const struct ast_dns_query *query)
{
    return;
}
 
AST_TEST_DEFINE(recurring_query_off_nominal)
{
    struct ast_dns_resolver terrible_resolver = {
        .name = "Harold P. Warren's Filmography",
        .priority = 0,
        .resolve = fail_resolve,
        .cancel = stub_cancel,
    };
 
    struct ast_dns_query_recurring *recurring;
 
    struct dns_resolve_data {
        const char *name;
        int rr_type;
        int rr_class;
        ast_dns_resolve_callback callback;
    } resolves [] = {
        { NULL,           T_A,       C_IN,      stub_callback },
        { "asterisk.org", -1,        C_IN,      stub_callback },
        { "asterisk.org", 65536 + 1, C_IN,      stub_callback },
        { "asterisk.org", T_A,       -1,        stub_callback },
        { "asterisk.org", T_A,       65536 + 1, stub_callback },
        { "asterisk.org", T_A,       C_IN,      NULL },
    };
    int i;
    enum ast_test_result_state res = AST_TEST_PASS;
 
    switch (cmd) {
    case TEST_INIT:
        info->name = "recurring_query_off_nominal";
        info->category = "/main/dns/recurring/";
        info->summary = "Test off-nominal recurring DNS resolution";
        info->description =
            "This test performs several off-nominal recurring DNS resolutions:\n"
            "\t* Attempt resolution with NULL name\n"
            "\t* Attempt resolution with invalid RR type\n"
            "\t* Attempt resolution with invalid RR class\n"
            "\t* Attempt resolution with NULL callback pointer\n"
            "\t* Attempt resolution with resolver that returns an error";
        return AST_TEST_NOT_RUN;
    case TEST_EXECUTE:
        break;
    }
 
    if (ast_dns_resolver_register(&recurring_resolver)) {
        ast_test_status_update(test, "Failed to register test resolver\n");
        return AST_TEST_FAIL;
    }
 
    for (i = 0; i < ARRAY_LEN(resolves); ++i) {
        recurring = ast_dns_resolve_recurring(resolves[i].name, resolves[i].rr_type, resolves[i].rr_class,
                resolves[i].callback, NULL);
        if (recurring) {
            ast_test_status_update(test, "Successfully performed recurring resolution with invalid data\n");
            ast_dns_resolve_recurring_cancel(recurring);
            ao2_ref(recurring, -1);
            res = AST_TEST_FAIL;
        }
    }
 
    ast_dns_resolver_unregister(&recurring_resolver);
 
    if (ast_dns_resolver_register(&terrible_resolver)) {
        ast_test_status_update(test, "Failed to register the DNS resolver\n");
        return AST_TEST_FAIL;
    }
 
    recurring = ast_dns_resolve_recurring("asterisk.org", T_A, C_IN, stub_callback, NULL);
 
    ast_dns_resolver_unregister(&terrible_resolver);
 
    if (recurring) {
        ast_test_status_update(test, "Successfully performed recurring resolution with invalid data\n");
        ast_dns_resolve_recurring_cancel(recurring);
        ao2_ref(recurring, -1);
        return AST_TEST_FAIL;
    }
 
    return res;
}
 
AST_TEST_DEFINE(recurring_query_cancel_between)
{
    RAII_VAR(struct ast_dns_query_recurring *, recurring_query, NULL, ao2_cleanup);
    RAII_VAR(struct recurring_data *, rdata, NULL, ao2_cleanup);
 
    enum ast_test_result_state res = AST_TEST_PASS;
    struct timespec timeout;
 
    switch (cmd) {
    case TEST_INIT:
        info->name = "recurring_query_cancel_between";
        info->category = "/main/dns/recurring/";
        info->summary = "Test canceling a recurring DNS query during the downtime between queries";
        info->description = "This test does the following:\n"
            "\t* Issue a recurring DNS query.\n"
            "\t* Once results have been returned, cancel the recurring query.\n"
            "\t* Wait a while to ensure that no more queries are occurring.";
        return AST_TEST_NOT_RUN;
    case TEST_EXECUTE:
        break;
    }
 
    if (ast_dns_resolver_register(&recurring_resolver)) {
        ast_test_status_update(test, "Failed to register recurring DNS resolver\n");
        return AST_TEST_FAIL;
    }
 
    rdata = recurring_data_alloc();
    if (!rdata) {
        ast_test_status_update(test, "Failed to allocate data necessary for recurring test\n");
        res = AST_TEST_FAIL;
        goto cleanup;
    }
 
    rdata->ttl1 = 5;
    rdata->ttl2 = 20;
 
    recurring_query = ast_dns_resolve_recurring("asterisk.org", T_A, C_IN, async_callback, rdata);
    if (!recurring_query) {
        ast_test_status_update(test, "Unable to make recurring query\n");
        res = AST_TEST_FAIL;
        goto cleanup;
    }
 
    if (wait_for_resolution(test, rdata, 0, 1, 1, 0)) {
        res = AST_TEST_FAIL;
        goto cleanup;
    }
 
    if (ast_dns_resolve_recurring_cancel(recurring_query)) {
        ast_test_status_update(test, "Failed to cancel recurring query\n");
        res = AST_TEST_FAIL;
        goto cleanup;
    }
 
    /* Query has been canceled, so let's wait to make sure that we don't get
     * told another query has occurred.
     */
    timeout = ast_tsnow();
    timeout.tv_sec += 10;
 
    ast_mutex_lock(&rdata->lock);
    while (!rdata->query_complete) {
        if (ast_cond_timedwait(&rdata->cond, &rdata->lock, &timeout) == ETIMEDOUT) {
            break;
        }
    }
    ast_mutex_unlock(&rdata->lock);
 
    if (rdata->query_complete) {
        ast_test_status_update(test, "Recurring query occurred after cancellation\n");
        res = AST_TEST_FAIL;
        goto cleanup;
    }
 
cleanup:
    ast_dns_resolver_unregister(&recurring_resolver);
    return res;
}
 
AST_TEST_DEFINE(recurring_query_cancel_during)
{
 
    RAII_VAR(struct ast_dns_query_recurring *, recurring_query, NULL, ao2_cleanup);
    RAII_VAR(struct recurring_data *, rdata, NULL, ao2_cleanup);
 
    enum ast_test_result_state res = AST_TEST_PASS;
    struct timespec timeout;
 
    switch (cmd) {
    case TEST_INIT:
        info->name = "recurring_query_cancel_during";
        info->category = "/main/dns/recurring/";
        info->summary = "Cancel a recurring DNS query while a query is actually happening";
        info->description = "This test does the following:\n"
            "\t* Initiate a recurring DNS query.\n"
            "\t* Allow the initial query to complete, and a second query to start\n"
            "\t* Cancel the recurring query while the second query is executing\n"
            "\t* Ensure that the resolver's cancel() method was called\n"
            "\t* Wait a while to make sure that recurring queries are no longer occurring";
        return AST_TEST_NOT_RUN;
    case TEST_EXECUTE:
        break;
    }
 
    if (ast_dns_resolver_register(&recurring_resolver)) {
        ast_test_status_update(test, "Failed to register recurring DNS resolver\n");
        return AST_TEST_FAIL;
    }
 
    rdata = recurring_data_alloc();
    if (!rdata) {
        ast_test_status_update(test, "Failed to allocate data necessary for recurring test\n");
        res = AST_TEST_FAIL;
        goto cleanup;
    }
 
    rdata->ttl1 = 5;
    rdata->ttl2 = 20;
 
    recurring_query = ast_dns_resolve_recurring("asterisk.org", T_A, C_IN, async_callback, rdata);
    if (!recurring_query) {
        ast_test_status_update(test, "Failed to make recurring DNS query\n");
        res = AST_TEST_FAIL;
        goto cleanup;
    }
 
    if (wait_for_resolution(test, rdata, 0, 1, 1, 0)) {
        res = AST_TEST_FAIL;
        goto cleanup;
    }
 
    /* Initial query has completed. Now let's make the next query expect a cancelation */
    rdata->cancel_expected = 1;
 
    /* Wait to be told that the query should be canceled  */
    ast_mutex_lock(&rdata->lock);
    while (!rdata->cancel_ready) {
        ast_cond_wait(&rdata->cond, &rdata->lock);
    }
    rdata->cancel_expected = 0;
    ast_mutex_unlock(&rdata->lock);
 
    if (ast_dns_resolve_recurring_cancel(recurring_query)) {
        ast_test_status_update(test, "Failed to cancel recurring DNS query\n");
        res = AST_TEST_FAIL;
        goto cleanup;
    }
 
    /* Query has been canceled. We'll be told that the query in flight has completed. */
    if (wait_for_resolution(test, rdata, 0, 2, 1, 1)) {
        res = AST_TEST_FAIL;
        goto cleanup;
    }
 
    /* Now ensure that no more queries get completed after cancellation. */
    timeout = ast_tsnow();
    timeout.tv_sec += 10;
 
    ast_mutex_lock(&rdata->lock);
    while (!rdata->query_complete) {
        if (ast_cond_timedwait(&rdata->cond, &rdata->lock, &timeout) == ETIMEDOUT) {
            break;
        }
    }
    ast_mutex_unlock(&rdata->lock);
 
    if (rdata->query_complete) {
        ast_test_status_update(test, "Recurring query occurred after cancellation\n");
        res = AST_TEST_FAIL;
        goto cleanup;
    }
 
cleanup:
    ast_dns_resolver_unregister(&recurring_resolver);
    return res;
}
 
static int unload_module(void)
{
    AST_TEST_UNREGISTER(recurring_query);
    AST_TEST_UNREGISTER(recurring_query_off_nominal);
    AST_TEST_UNREGISTER(recurring_query_cancel_between);
    AST_TEST_UNREGISTER(recurring_query_cancel_during);
 
    return 0;
}
 
static int load_module(void)
{
    AST_TEST_REGISTER(recurring_query);
    AST_TEST_REGISTER(recurring_query_off_nominal);
    AST_TEST_REGISTER(recurring_query_cancel_between);
    AST_TEST_REGISTER(recurring_query_cancel_during);
 
    return AST_MODULE_LOAD_SUCCESS;
}
 
AST_MODULE_INFO_STANDARD(ASTERISK_GPL_KEY, "Recurring DNS query tests");