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libwebsockets/minimal-examples/api-tests/api-test-async-dns/main.c
Andy Green c591e1adfc asynchronous dns for ipv4 and ipv6
This adds the option to have lws do its own dns resolution on
the event loop, without blocking.  Existing implementations get
the name resolution done by the libc, which is blocking.  In
the case you are opening client connections but need to carefully
manage latency, another connection opening and doing the name
resolution becomes a big problem.

Currently it supports

 - ipv4 / A records
 - ipv6 / AAAA records
 - ipv4-over-ipv6 ::ffff:1.2.3.4 A record promotion for ipv6
 - only one server supported over UDP :53
 - nameserver discovery on linux, windows, freertos

It also has some nice advantages

 - lws-style paranoid response parsing
 - random unique tid generation to increase difficulty of poisoning
 - it's really integrated with the lws event loop, it does not spawn
   threads or use the libc resolver, and of course no blocking at all
 - platform-specific server address capturing (from /etc/resolv.conf
   on linux, windows apis on windows)
 - it has LRU caching
 - piggybacking (multiple requests before the first completes go on
   a list on the first request, not spawn multiple requests)
 - observes TTL in cache
 - TTL and timeout use lws_sul timers on the event loop
 - ipv6 pieces only built if cmake LWS_IPV6 enabled
2019-09-19 06:54:53 +01:00

315 lines
7.2 KiB
C

/*
* lws-api-test-async-dns
*
* Written in 2019 by Andy Green <andy@warmcat.com>
*
* This file is made available under the Creative Commons CC0 1.0
* Universal Public Domain Dedication.
*
* This api test confirms various kinds of async dns apis
*/
#include <libwebsockets.h>
#include <signal.h>
static int interrupted, dtest, ok, fail, exp = 26;
struct lws_context *context;
/*
* These are used to test the apis to parse and print ipv4 / ipv6 literal
* address strings for various cases.
*
* Expected error cases are not used to test the ip data -> string api.
*/
static const struct ipparser_tests {
const char *test;
int rlen;
const char *emit_test;
int emit_len;
uint8_t b[16];
} ipt[] = {
{ "2001:db8:85a3:0:0:8a2e:370:7334", 16,
"2001:db8:85a3::8a2e:370:7334", 28,
{ 0x20, 0x01, 0x0d, 0xb8, 0x85, 0xa3, 0x00, 0x00,
0x00, 0x00, 0x8a, 0x2e, 0x03, 0x70, 0x73, 0x34 } },
{ "2001:db8:85a3::8a2e:370:7334", 16,
"2001:db8:85a3::8a2e:370:7334", 28,
{ 0x20, 0x01, 0x0d, 0xb8, 0x85, 0xa3, 0x00, 0x00,
0x00, 0x00, 0x8a, 0x2e, 0x03, 0x70, 0x73, 0x34 } },
{ "::1", 16, "::1", 3,
{ 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1 } },
{ "::", 16, "::", 2,
{ 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 } },
{ "::ffff:192.0.2.128", 16, "::ffff:192.0.2.128", 18,
{ 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0xff, 0xff, 0xc0, 0x00, 0x02, 0x80 } },
{ "cats", -1, "", 0,
{ 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1 } },
{ "onevalid.bogus.warmcat.com", -1, "", 0,
{ 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1 } },
{ "1.cat.dog.com", -1, "", 0,
{ 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1 } },
{ ":::1", -8, "", 0,
{ 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1 } },
{ "0:0::0:1", 16, "::1", 3,
{ 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1 } },
{ "1.2.3.4", 4, "1.2.3.4", 7, { 1, 2, 3, 4 } },
};
static const struct async_dns_tests {
const char *dns_name;
int recordtype;
int addrlen;
uint8_t ads[16];
} adt[] = {
{ "warmcat.com", LWS_ADNS_RECORD_A, 4,
{ 46, 105, 127, 147, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, } },
{ "libwebsockets.org", LWS_ADNS_RECORD_A, 4,
{ 46, 105, 127, 147, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, } },
{ "doesntexist", LWS_ADNS_RECORD_A, 0,
{ 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, } },
{ "localhost", LWS_ADNS_RECORD_A, 4,
{ 127, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, } },
{ "ipv4only.warmcat.com", LWS_ADNS_RECORD_A, 4,
{ 46, 105, 127, 147, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, } },
{ "onevalid.bogus.warmcat.com", LWS_ADNS_RECORD_A, 4,
{ 46, 105, 127, 147, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, } },
#if defined(LWS_WITH_IPV6)
{ "warmcat.com", LWS_ADNS_RECORD_AAAA, 16, /* check ipv6 */
{ 0x20, 0x01, 0x41, 0xd0, 0x00, 0x02, 0xee, 0x93,
0, 0, 0, 0, 0, 0, 0, 0, } },
{ "ipv6only.warmcat.com", LWS_ADNS_RECORD_AAAA, 16, /* check ipv6 */
{ 0x20, 0x01, 0x41, 0xd0, 0x00, 0x02, 0xee, 0x93,
0, 0, 0, 0, 0, 0, 0, 0, } },
#endif
};
static lws_sorted_usec_list_t sul;
struct lws *
cb1(struct lws *wsi_unused, const char *ads, const struct addrinfo *a, int n,
void *opaque);
static void
next_test_cb(lws_sorted_usec_list_t *sul)
{
int m;
lwsl_notice("%s: querying %s\n", __func__, adt[dtest].dns_name);
m = lws_async_dns_query(context, 0,
adt[dtest].dns_name,
adt[dtest].recordtype, cb1, NULL,
context);
if (m != LADNS_RET_CONTINUING && m != LADNS_RET_FOUND) {
lwsl_err("%s: adns 1 failed: %d\n", __func__, m);
interrupted = 1;
}
}
struct lws *
cb1(struct lws *wsi_unused, const char *ads, const struct addrinfo *a, int n,
void *opaque)
{
const struct addrinfo *ac = a;
int ctr = 0, alen;
uint8_t *addr;
char buf[64];
dtest++;
if (!ac)
lwsl_warn("%s: no results\n", __func__);
/* dump the results */
while (ac) {
if (ac->ai_family == AF_INET) {
addr = (uint8_t *)&(((struct sockaddr_in *)
ac->ai_addr)->sin_addr.s_addr);
alen = 4;
} else {
addr = (uint8_t *)&(((struct sockaddr_in6 *)
ac->ai_addr)->sin6_addr.s6_addr);
alen = 16;
}
strcpy(buf, "unknown");
lws_write_numeric_address(addr, alen, buf, sizeof(buf));
lwsl_warn("%s: %d: %s %d %s\n", __func__, ctr++, ads, alen, buf);
ac = ac->ai_next;
}
ac = a;
while (ac) {
if (ac->ai_family == AF_INET) {
addr = (uint8_t *)&(((struct sockaddr_in *)
ac->ai_addr)->sin_addr.s_addr);
alen = 4;
} else {
#if defined(LWS_WITH_IPV6)
addr = (uint8_t *)&(((struct sockaddr_in6 *)
ac->ai_addr)->sin6_addr.s6_addr);
alen = 16;
#else
goto again;
#endif
}
if (alen == adt[dtest - 1].addrlen &&
!memcmp(adt[dtest - 1].ads, addr, alen)) {
ok++;
goto next;
}
#if !defined(LWS_WITH_IPV6)
again:
#endif
ac = ac->ai_next;
}
/* testing for NXDOMAIN? */
if (!a && !adt[dtest - 1].addrlen) {
ok++;
goto next;
}
lwsl_err("%s: dns test %d: no match\n", __func__, dtest);
fail++;
next:
lws_async_dns_freeaddrinfo(a);
if (dtest == (int)LWS_ARRAY_SIZE(adt))
interrupted = 1;
else
lws_sul_schedule(context, 0, &sul, next_test_cb, 1);
return NULL;
}
void sigint_handler(int sig)
{
interrupted = 1;
}
int
main(int argc, const char **argv)
{
int n = 1, logs = LLL_USER | LLL_ERR | LLL_WARN | LLL_NOTICE;
struct lws_context_creation_info info;
const char *p;
/* the normal lws init */
signal(SIGINT, sigint_handler);
if ((p = lws_cmdline_option(argc, argv, "-d")))
logs = atoi(p);
lws_set_log_level(logs, NULL);
lwsl_user("LWS API selftest: Async DNS\n");
memset(&info, 0, sizeof info); /* otherwise uninitialized garbage */
info.port = CONTEXT_PORT_NO_LISTEN;
info.options = LWS_SERVER_OPTION_DO_SSL_GLOBAL_INIT;
context = lws_create_context(&info);
if (!context) {
lwsl_err("lws init failed\n");
return 1;
}
/* ip address parser tests */
for (n = 0; n < (int)LWS_ARRAY_SIZE(ipt); n++) {
uint8_t u[16];
int m = lws_parse_numeric_address(ipt[n].test, u, sizeof(u));
if (m != ipt[n].rlen) {
lwsl_err("%s: fail %s ret %d\n",
__func__, ipt[n].test, m);
fail++;
continue;
}
if (m > 0) {
if (memcmp(ipt[n].b, u, m)) {
lwsl_err("%s: fail %s compare\n", __func__,
ipt[n].test);
lwsl_hexdump_notice(u, m);
fail++;
continue;
}
}
ok++;
}
/* ip address formatter tests */
for (n = 0; n < (int)LWS_ARRAY_SIZE(ipt); n++) {
char buf[64];
int m;
/* don't attempt to reverse the ones that are meant to fail */
if (ipt[n].rlen < 0)
continue;
m = lws_write_numeric_address(ipt[n].b, ipt[n].rlen, buf,
sizeof(buf));
if (m != ipt[n].emit_len) {
lwsl_err("%s: fail %s ret %d\n",
__func__, ipt[n].emit_test, m);
fail++;
continue;
}
if (m > 0) {
if (strcmp(ipt[n].emit_test, buf)) {
lwsl_err("%s: fail %s compare\n", __func__,
ipt[n].test);
lwsl_hexdump_notice(buf, m);
fail++;
continue;
}
}
ok++;
}
#if !defined(LWS_WITH_IPV6)
exp -= 2;
#endif
/* kick off the async dns tests */
lws_sul_schedule(context, 0, &sul, next_test_cb, 1);
/* the usual lws event loop */
n = 1;
while (n >= 0 && !interrupted)
n = lws_service(context, 0);
lws_context_destroy(context);
if (fail || ok != exp)
lwsl_user("Completed: PASS: %d / %d, FAIL: %d\n", ok, exp,
fail);
else
lwsl_user("Completed: ALL PASS: %d / %d\n", ok, exp);
return !(ok == exp && !fail);
}