CURLOPT_RESOLVE: Add support for multiple IP addresses per entry

This enables users to preresolve but still take advantage of happy
eyeballs and trying multiple addresses if some are not connecting.

Ref: https://github.com/curl/curl/pull/2260

4 files changed, 234 insertions, 2 deletions

diff --git a/tests/data/Makefile.inc b/tests/data/Makefile.inc
index 91e4dd924..892012988 100644
--- a/tests/data/Makefile.inc
+++ b/tests/data/Makefile.inc
@@ -172,7 +172,7 @@ test1525 test1526 test1527 test1528 test1529 test1530 test1531 test1532 \
 test1533 test1534 test1535 test1536 test1537 test1538 \
 test1540 \
 test1550 test1551 test1552 test1553 test1554 test1555 test1556 \
-test1600 test1601 test1602 test1603 test1604 test1605 test1606 \
+test1600 test1601 test1602 test1603 test1604 test1605 test1606 test1607 \
 \
 test1700 test1701 test1702 \
 \
diff --git a/tests/data/test1607 b/tests/data/test1607
new file mode 100644
index 000000000..9628324e4
--- /dev/null
+++ b/tests/data/test1607
@@ -0,0 +1,26 @@
+<testcase>
+<info>
+<keywords>
+unittest
+CURLOPT_RESOLVE
+</keywords>
+</info>
+
+#
+# Client-side
+<client>
+<server>
+none
+</server>
+<features>
+unittest
+</features>
+ <name>
+CURLOPT_RESOLVE parsing
+ </name>
+<tool>
+unit1607
+</tool>
+</client>
+
+</testcase>
diff --git a/tests/unit/Makefile.inc b/tests/unit/Makefile.inc
index bfb5c4d45..9a19f51d1 100644
--- a/tests/unit/Makefile.inc
+++ b/tests/unit/Makefile.inc
@@ -9,7 +9,7 @@ UNITPROGS = unit1300 unit1301 unit1302 unit1303 unit1304 unit1305 unit1307	\
  unit1308 unit1309 unit1323 \
  unit1330 unit1394 unit1395 unit1396 unit1397 unit1398	\
  unit1399	\
- unit1600 unit1601 unit1602 unit1603 unit1604 unit1605 unit1606
+ unit1600 unit1601 unit1602 unit1603 unit1604 unit1605 unit1606 unit1607
 
 unit1300_SOURCES = unit1300.c $(UNITFILES)
 unit1300_CPPFLAGS = $(AM_CPPFLAGS)
@@ -85,3 +85,6 @@ unit1605_CPPFLAGS = $(AM_CPPFLAGS)
 
 unit1606_SOURCES = unit1606.c $(UNITFILES)
 unit1606_CPPFLAGS = $(AM_CPPFLAGS)
+
+unit1607_SOURCES = unit1607.c $(UNITFILES)
+unit1607_CPPFLAGS = $(AM_CPPFLAGS)
diff --git a/tests/unit/unit1607.c b/tests/unit/unit1607.c
new file mode 100644
index 000000000..3e53d4d20
--- /dev/null
+++ b/tests/unit/unit1607.c
@@ -0,0 +1,203 @@
+/***************************************************************************
+ *                                  _   _ ____  _
+ *  Project                     ___| | | |  _ \| |
+ *                             / __| | | | |_) | |
+ *                            | (__| |_| |  _ <| |___
+ *                             \___|\___/|_| \_\_____|
+ *
+ * Copyright (C) 1998 - 2018, Daniel Stenberg, <daniel@haxx.se>, et al.
+ *
+ * This software is licensed as described in the file COPYING, which
+ * you should have received as part of this distribution. The terms
+ * are also available at https://curl.haxx.se/docs/copyright.html.
+ *
+ * You may opt to use, copy, modify, merge, publish, distribute and/or sell
+ * copies of the Software, and permit persons to whom the Software is
+ * furnished to do so, under the terms of the COPYING file.
+ *
+ * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
+ * KIND, either express or implied.
+ *
+ ***************************************************************************/
+#include "curlcheck.h"
+
+#include "urldata.h"
+#include "connect.h"
+#include "share.h"
+
+#include "memdebug.h" /* LAST include file */
+
+static struct Curl_easy *easy;
+struct curl_hash *hostcache;
+
+static CURLcode unit_setup(void)
+{
+  int res = CURLE_OK;
+
+  global_init(CURL_GLOBAL_ALL);
+
+  easy = curl_easy_init();
+  if(!easy)
+    return CURLE_OUT_OF_MEMORY;
+
+  hostcache = Curl_global_host_cache_init();
+  if(!hostcache)
+    return CURLE_OUT_OF_MEMORY;
+
+  return res;
+}
+
+static void unit_stop(void)
+{
+  curl_easy_cleanup(easy);
+  curl_global_cleanup();
+}
+
+struct testcase {
+  /* host:port:address[,address]... */
+  const char *optval;
+
+  /* lowercase host and port to retrieve the addresses from hostcache */
+  const char *host;
+  int port;
+
+  /* 0 to 9 addresses expected from hostcache */
+  const char *address[10];
+};
+
+
+/* In builds without IPv6 support CURLOPT_RESOLVE should skip over those
+   addresses, so we have to do that as well. */
+static const char skip = 0;
+#ifdef ENABLE_IPV6
+#define IPV6ONLY(x) x
+#else
+#define IPV6ONLY(x) &skip
+#endif
+
+/* CURLOPT_RESOLVE address parsing tests */
+static const struct testcase tests[] = {
+  /* spaces aren't allowed, for now */
+  { "test.com:80:127.0.0.1, 127.0.0.2",
+    "test.com", 80, { NULL, }
+  },
+  { "TEST.com:80:,,127.0.0.1,,,127.0.0.2,,,,::1,,,",
+    "test.com", 80, { "127.0.0.1", "127.0.0.2", IPV6ONLY("::1"), }
+  },
+  { "test.com:80:::1,127.0.0.1",
+    "test.com", 80, { IPV6ONLY("::1"), "127.0.0.1", }
+  },
+  { "test.com:80:[::1],127.0.0.1",
+    "test.com", 80, { IPV6ONLY("::1"), "127.0.0.1", }
+  },
+  { "test.com:80:::1",
+    "test.com", 80, { IPV6ONLY("::1"), }
+  },
+  { "test.com:80:[::1]",
+    "test.com", 80, { IPV6ONLY("::1"), }
+  },
+  { "test.com:80:127.0.0.1",
+    "test.com", 80, { "127.0.0.1", }
+  },
+  { "test.com:80:,127.0.0.1",
+    "test.com", 80, { "127.0.0.1", }
+  },
+  { "test.com:80:127.0.0.1,",
+    "test.com", 80, { "127.0.0.1", }
+  },
+  { "test.com:0:127.0.0.1",
+    "test.com", 0, { "127.0.0.1", }
+  },
+};
+
+UNITTEST_START
+  int i;
+  int testnum = sizeof(tests) / sizeof(struct testcase);
+
+  for(i = 0; i < testnum; ++i, curl_easy_reset(easy)) {
+    int j;
+    int addressnum = sizeof tests[i].address / sizeof *tests[i].address;
+    struct Curl_addrinfo *addr;
+    struct Curl_dns_entry *dns;
+    struct curl_slist *list;
+    void *entry_id;
+    bool problem = false;
+
+    Curl_hostcache_clean(easy, hostcache);
+    easy->dns.hostcache = hostcache;
+    easy->dns.hostcachetype = HCACHE_GLOBAL;
+
+    list = curl_slist_append(NULL, tests[i].optval);
+    curl_easy_setopt(easy, CURLOPT_RESOLVE, list);
+
+    Curl_loadhostpairs(easy);
+
+    entry_id = (void *)aprintf("%s:%d", tests[i].host, tests[i].port);
+    dns = Curl_hash_pick(easy->dns.hostcache, entry_id, strlen(entry_id) + 1);
+    free(entry_id);
+    entry_id = NULL;
+
+    addr = dns ? dns->addr : NULL;
+
+    for(j = 0; j < addressnum; ++j) {
+      long port = 0;
+      char ipaddress[MAX_IPADR_LEN] = {0};
+
+      if(!addr && !tests[i].address[j])
+        break;
+
+      if(tests[i].address[j] == &skip)
+        continue;
+
+      if(addr && !Curl_getaddressinfo(addr->ai_addr,
+                                      ipaddress, &port)) {
+        fprintf(stderr, "%s:%d tests[%d] failed. getaddressinfo failed.\n",
+                __FILE__, __LINE__, i);
+        problem = true;
+        break;
+      }
+
+      if(addr && !tests[i].address[j]) {
+        fprintf(stderr, "%s:%d tests[%d] failed. the retrieved addr "
+                "is %s but tests[%d].address[%d] is NULL.\n",
+                __FILE__, __LINE__, i, ipaddress, i, j);
+        problem = true;
+        break;
+      }
+
+      if(!addr && tests[i].address[j]) {
+        fprintf(stderr, "%s:%d tests[%d] failed. the retrieved addr "
+                "is NULL but tests[%d].address[%d] is %s.\n",
+                __FILE__, __LINE__, i, i, j, tests[i].address[j]);
+        problem = true;
+        break;
+      }
+
+      if(!curl_strequal(ipaddress, tests[i].address[j])) {
+        fprintf(stderr, "%s:%d tests[%d] failed. the retrieved addr "
+                "%s is not equal to tests[%d].address[%d] %s.\n",
+                __FILE__, __LINE__, i, ipaddress, i, j, tests[i].address[j]);
+        problem = true;
+        break;
+      }
+
+      if(port != tests[i].port) {
+        fprintf(stderr, "%s:%d tests[%d] failed. the retrieved port "
+                "for tests[%d].address[%d] is %ld but tests[%d].port is %d.\n",
+                __FILE__, __LINE__, i, i, j, port, i, tests[i].port);
+        problem = true;
+        break;
+      }
+
+      addr = addr->ai_next;
+    }
+
+    Curl_hostcache_clean(easy, easy->dns.hostcache);
+    curl_slist_free_all(list);
+
+    if(problem) {
+      unitfail++;
+      continue;
+    }
+  }
+UNITTEST_STOP