mirror of
https://github.com/libevent/libevent.git
synced 2025-01-09 00:56:20 +08:00
Fix an annoying evdns crash bug, and add more unit tests for evdns.
svn:r1406
This commit is contained in:
Nick Mathewson
parent
a5006d80cd
commit
213dc2a2ef
56
evdns.c
56
evdns.c
@ -623,7 +623,7 @@ static void
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request_finished(struct evdns_request *const req, struct evdns_request **head) {
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struct evdns_base *base = req->base;
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int was_inflight = (head != &base->req_waiting_head);
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EVDNS_LOCK(req->base);
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EVDNS_LOCK(base);
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if (head)
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evdns_request_remove(req, head);
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@ -648,6 +648,7 @@ request_finished(struct evdns_request *const req, struct evdns_request **head) {
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mm_free(req);
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evdns_requests_pump_waiting_queue(base);
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EVDNS_UNLOCK(base);
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}
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/* This is called when a server returns a funny error code. */
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@ -849,6 +850,8 @@ reply_handle(struct evdns_request *const req, u16 flags, u32 ttl, struct reply *
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} else {
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/* all ok, tell the user */
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reply_schedule_callback(req, ttl, 0, reply);
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if (req == req->ns->probe_request)
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req->ns->probe_request = NULL; /* Avoid double-free */
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nameserver_up(req->ns);
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request_finished(req, &REQ_HEAD(req->base, req->trans_id));
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}
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@ -2075,11 +2078,12 @@ evdns_server_request_get_requesting_addr(struct evdns_server_request *_req, stru
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static void
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evdns_request_timeout_callback(evutil_socket_t fd, short events, void *arg) {
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struct evdns_request *const req = (struct evdns_request *) arg;
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struct evdns_base *base = req->base;
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(void) fd;
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(void) events;
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log(EVDNS_LOG_DEBUG, "Request %lx timed out", (unsigned long) arg);
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EVDNS_LOCK(req->base);
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EVDNS_LOCK(base);
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req->ns->timedout++;
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if (req->ns->timedout > req->base->global_max_nameserver_timeout) {
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@ -2096,7 +2100,7 @@ evdns_request_timeout_callback(evutil_socket_t fd, short events, void *arg) {
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(void) evtimer_del(&req->timeout_event);
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evdns_request_transmit(req);
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}
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EVDNS_UNLOCK(req->base);
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EVDNS_UNLOCK(base);
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}
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/* try to send a request to a given server. */
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@ -2502,6 +2506,27 @@ static void
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evdns_request_remove(struct evdns_request *req, struct evdns_request **head)
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{
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ASSERT_LOCKED(req->base);
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#if 0
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{
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struct evdns_request *ptr;
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int found = 0;
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assert(*head != NULL);
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ptr = *head;
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do {
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if (ptr == req) {
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found = 1;
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break;
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}
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ptr = ptr->next;
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} while (ptr != *head);
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assert(found);
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assert(req->next);
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}
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#endif
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if (req->next == req) {
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/* only item in the list */
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*head = NULL;
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@ -2510,6 +2535,7 @@ evdns_request_remove(struct evdns_request *req, struct evdns_request **head)
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req->prev->next = req->next;
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if (*head == req) *head = req->next;
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}
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req->next = req->prev = NULL;
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}
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/* insert into the tail of the queue */
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@ -3061,13 +3087,27 @@ strtok_r(char *s, const char *delim, char **state) {
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/* helper version of atoi which returns -1 on error */
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static int
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strtoint(const char *const str) {
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strtoint(const char *const str)
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{
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char *endptr;
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const int r = strtol(str, &endptr, 10);
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if (*endptr) return -1;
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return r;
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}
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/* Parse a number of seconds into a timeval; return -1 on error. */
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static int
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strtotimeval(const char *const str, struct timeval *out)
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{
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double d;
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char *endptr;
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d = strtod(str, &endptr);
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if (*endptr) return -1;
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out->tv_sec = (int) d;
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out->tv_usec = (int) ((d - (int) d)*1000000);
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return 0;
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}
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/* helper version of atoi that returns -1 on error and clips to bounds. */
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static int
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strtoint_clipped(const char *const str, int min, int max)
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@ -3142,11 +3182,11 @@ evdns_base_set_option_impl(struct evdns_base *base,
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if (!base->global_search_state) return -1;
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base->global_search_state->ndots = ndots;
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} else if (!strncmp(option, "timeout:", 8)) {
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const int timeout = strtoint(val);
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if (timeout == -1) return -1;
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struct timeval tv;
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if (strtotimeval(val, &tv) == -1) return -1;
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if (!(flags & DNS_OPTION_MISC)) return 0;
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log(EVDNS_LOG_DEBUG, "Setting timeout to %d", timeout);
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base->global_timeout.tv_sec = timeout;
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log(EVDNS_LOG_DEBUG, "Setting timeout to %s", val);
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memcpy(&base->global_timeout, &tv, sizeof(struct timeval));
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} else if (!strncmp(option, "max-timeouts:", 12)) {
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const int maxtimeout = strtoint_clipped(val, 1, 255);
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if (maxtimeout == -1) return -1;
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@ -452,7 +452,8 @@ end:
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static struct evdns_server_port *
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get_generic_server(struct event_base *base,
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ev_uint64_t portnum,
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struct generic_dns_server_table *tab)
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evdns_request_callback_fn_type cb,
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void *arg)
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{
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struct evdns_server_port *port = NULL;
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evutil_socket_t sock;
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@ -472,7 +473,7 @@ get_generic_server(struct event_base *base,
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if (bind(sock, (struct sockaddr*)&my_addr, sizeof(my_addr)) < 0) {
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tt_abort_perror("bind");
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}
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port = evdns_add_server_port_with_base(base, sock, 0, generic_dns_server_cb, tab);
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port = evdns_add_server_port_with_base(base, sock, 0, cb, arg);
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return port;
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end:
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@ -544,7 +545,8 @@ dns_search_test(void *arg)
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struct generic_dns_callback_result r1, r2, r3, r4, r5;
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port = get_generic_server(base, 53900, search_table);
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port = get_generic_server(base, 53900, generic_dns_server_cb,
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search_table);
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tt_assert(port);
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dns = evdns_base_new(base, 0);
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@ -576,10 +578,161 @@ dns_search_test(void *arg)
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tt_int_op(r5.result, ==, DNS_ERR_NOTEXIST);
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end:
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if (dns)
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evdns_base_free(dns, 0);
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if (port)
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evdns_close_server_port(port);
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}
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static void
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fail_server_cb(struct evdns_server_request *req, void *data)
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{
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const char *question;
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int *count = data;
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struct in_addr in;
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/* Drop the first N requests that we get. */
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if (*count > 0) {
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--*count;
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tt_want(! evdns_server_request_drop(req));
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return;
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}
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if (req->nquestions != 1)
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TT_DIE(("Only handling one question at a time; got %d",
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req->nquestions));
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question = req->questions[0]->name;
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if (!evutil_ascii_strcasecmp(question, "google.com")) {
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/* Detect a probe, and get out of the loop. */
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event_base_loopexit(exit_base, NULL);
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}
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evutil_inet_pton(AF_INET, "16.32.64.128", &in);
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evdns_server_request_add_a_reply(req, question, 1, &in.s_addr,
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100);
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tt_assert(! evdns_server_request_respond(req, 0))
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return;
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end:
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tt_want(! evdns_server_request_drop(req));
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}
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static void
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dns_retry_test(void *arg)
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{
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struct basic_test_data *data = arg;
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struct event_base *base = data->base;
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struct evdns_server_port *port = NULL;
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struct evdns_base *dns = NULL;
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int drop_count = 2;
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struct generic_dns_callback_result r1;
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port = get_generic_server(base, 53900, fail_server_cb,
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&drop_count);
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tt_assert(port);
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dns = evdns_base_new(base, 0);
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tt_assert(!evdns_base_nameserver_ip_add(dns, "127.0.0.1:53900"));
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tt_assert(! evdns_base_set_option(dns, "timeout:", "0.3", DNS_OPTIONS_ALL));
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tt_assert(! evdns_base_set_option(dns, "max-timeouts:", "10", DNS_OPTIONS_ALL));
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evdns_base_resolve_ipv4(dns, "host.example.com", 0,
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generic_dns_callback, &r1);
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n_replies_left = 1;
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exit_base = base;
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event_base_dispatch(base);
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tt_int_op(drop_count, ==, 0);
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tt_int_op(r1.type, ==, DNS_IPv4_A);
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tt_int_op(r1.count, ==, 1);
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tt_int_op(((ev_uint32_t*)r1.addrs)[0], ==, htonl(0x10204080));
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/* Now try again, but this time have the server get treated as
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* failed, so we can send it a test probe. */
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drop_count = 4;
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tt_assert(! evdns_base_set_option(dns, "max-timeouts:", "3", DNS_OPTIONS_ALL));
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tt_assert(! evdns_base_set_option(dns, "attempts:", "4", DNS_OPTIONS_ALL));
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memset(&r1, 0, sizeof(r1));
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evdns_base_resolve_ipv4(dns, "host.example.com", 0,
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generic_dns_callback, &r1);
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n_replies_left = 2;
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/* This will run until it answers the "google.com" probe request. */
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/* XXXX It takes 10 seconds to retry the probe, which makes the test
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* slow. */
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event_base_dispatch(base);
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/* We'll treat the server as failed here. */
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tt_int_op(r1.result, ==, DNS_ERR_TIMEOUT);
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/* It should work this time. */
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tt_int_op(drop_count, ==, 0);
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evdns_base_resolve_ipv4(dns, "host.example.com", 0,
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generic_dns_callback, &r1);
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event_base_dispatch(base);
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tt_int_op(r1.type, ==, DNS_IPv4_A);
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tt_int_op(((ev_uint32_t*)r1.addrs)[0], ==, htonl(0x10204080));
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end:
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if (dns)
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evdns_base_free(dns, 0);
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if (port)
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evdns_close_server_port(port);
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}
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#if 0
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static void
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dns_probe_test(void *arg)
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{
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struct basic_test_data *data = arg;
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struct event_base *base = data->base;
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struct evdns_server_port *port = NULL;
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struct evdns_base *dns = NULL;
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int drop_count = 4;
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struct generic_dns_callback_result r1;
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port = get_generic_server(base, 53900, fail_twice_server_cb,
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&drop_count);
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tt_assert(port);
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dns = evdns_base_new(base, 0);
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tt_assert(!evdns_base_nameserver_ip_add(dns, "127.0.0.1:53900"));
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tt_assert(! evdns_base_set_option(dns, "timeout:", "0.2", DNS_OPTIONS_ALL));
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tt_assert(! evdns_base_set_option(dns, "max-timeouts:", "4", DNS_OPTIONS_ALL));
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evdns_base_resolve_ipv4(dns, "host.example.com", 0,
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generic_dns_callback, &r1);
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n_replies_left = 1;
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exit_base = base;
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event_base_dispatch(base);
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tt_int_op(drop_count, ==, 1);
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tt_int_op(r1.type, ==, DNS_IPv4_A);
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tt_int_op(r1.count, ==, 1);
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tt_int_op(((ev_uint32_t*)r1.addrs)[0], ==, htonl(0x10204080));
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event_base_dispatch(base);
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end:
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if (dns)
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evdns_base_free(dns, 0);
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if (port)
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evdns_close_server_port(port);
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}
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#endif
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#define DNS_LEGACY(name, flags) \
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{ #name, run_legacy_test_fn, flags|TT_LEGACY, &legacy_setup, \
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@ -592,6 +745,7 @@ struct testcase_t dns_testcases[] = {
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DNS_LEGACY(gethostbyaddr, TT_FORK|TT_NEED_BASE|TT_NEED_DNS),
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{ "resolve_reverse", dns_resolve_reverse, TT_FORK, NULL, NULL },
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{ "search", dns_search_test, TT_FORK|TT_NEED_BASE, &basic_setup, NULL },
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{ "retry", dns_retry_test, TT_FORK|TT_NEED_BASE, &basic_setup, NULL },
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END_OF_TESTCASES
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};
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