@@ -628,9 +628,11 @@ if (NOT WIN32)

     target_compile_options(openvpn PRIVATE -DPLUGIN_LIBDIR=\"${PLUGIN_DIR}\")

     find_library(resolv resolv)

-    # some platform like BSDs already include resolver functionality in the libc and not have an extra resolv library

+    # some platform like BSDs already include resolver functionality in the libc

+    # and do not have an extra resolv library

     if (${resolv} OR APPLE)

-        target_link_libraries(openvpn PUBLIC -lresolv)

+        set(RESOLV_LIBRARIES resolv)

+        target_link_libraries(openvpn PUBLIC ${RESOLV_LIBRARIES})

     endif ()

 endif ()

@@ -653,6 +655,7 @@ if (BUILD_TESTING)

         "test_packet_id"

         "test_pkt"

         "test_provider"

+        "test_socket"

         "test_ssl"

         "test_user_pass"

         "test_push_update_msg"

@@ -849,6 +852,16 @@ if (BUILD_TESTING)

         src/openvpn/base64.c

         )

+    target_link_libraries(test_socket PUBLIC ${RESOLV_LIBRARIES})

+    target_sources(test_socket PRIVATE

+        tests/unit_tests/openvpn/mock_get_random.c

+        tests/unit_tests/openvpn/mock_management.c

+        tests/unit_tests/openvpn/mock_win32_execve.c

+        src/openvpn/env_set.c

+        src/openvpn/run_command.c

+        src/openvpn/socket_util.c

+        )

+

     target_sources(test_user_pass PRIVATE

         tests/unit_tests/openvpn/mock_get_random.c

         tests/unit_tests/openvpn/mock_win32_execve.c

@@ -4,23 +4,17 @@ EXTRA_DIST = input

 AM_TESTSUITE_SUMMARY_HEADER = ' for $(PACKAGE_STRING) Unit-Tests'

-test_binaries=

+test_binaries = crypto_testdriver packet_id_testdriver auth_token_testdriver \

+	ncp_testdriver misc_testdriver pkt_testdriver ssl_testdriver \

+	user_pass_testdriver push_update_msg_testdriver provider_testdriver socket_testdriver

 if HAVE_LD_WRAP_SUPPORT

 test_binaries += argv_testdriver buffer_testdriver

-endif

-

-test_binaries += crypto_testdriver packet_id_testdriver auth_token_testdriver ncp_testdriver misc_testdriver \

-	pkt_testdriver ssl_testdriver user_pass_testdriver push_update_msg_testdriver

-

-if HAVE_LD_WRAP_SUPPORT

 if !WIN32

 test_binaries += tls_crypt_testdriver

 endif

 endif

-test_binaries += provider_testdriver

-

 if WIN32

 test_binaries += cryptoapi_testdriver

 LDADD = -lws2_32

@@ -343,4 +337,21 @@ push_update_msg_testdriver_SOURCES = test_push_update_msg.c \

 	$(top_srcdir)/src/openvpn/platform.c \

 	$(top_srcdir)/src/openvpn/push_util.c \

 	$(top_srcdir)/src/openvpn/options_util.c \

-	$(top_srcdir)/src/openvpn/otime.c

\ No newline at end of file

+	$(top_srcdir)/src/openvpn/otime.c

+

+socket_testdriver_CFLAGS  = \

+	-I$(top_srcdir)/include -I$(top_srcdir)/src/compat -I$(top_srcdir)/src/openvpn \

+	-DSOURCEDIR=\"$(top_srcdir)\" @TEST_CFLAGS@

+

+socket_testdriver_LDFLAGS = @TEST_LDFLAGS@ $(SOCKETS_LIBS)

+

+socket_testdriver_SOURCES = test_socket.c \

+	mock_msg.c test_common.h  \

+	mock_get_random.c \

+	mock_management.c \

+	$(top_srcdir)/src/openvpn/buffer.c \

+	$(top_srcdir)/src/openvpn/win32-util.c \

+	$(top_srcdir)/src/openvpn/platform.c \

+	$(top_srcdir)/src/openvpn/env_set.c \

+	$(top_srcdir)/src/openvpn/run_command.c \

+	$(top_srcdir)/src/openvpn/socket_util.c

@@ -46,4 +46,18 @@ management_query_pk_sig(struct management *man, const char *b64_data, const char

 {

     return NULL;

 }

+

+void

+management_set_state(struct management *man, const int state, const char *detail,

+                     const in_addr_t *tun_local_ip, const struct in6_addr *tun_local_ip6,

+                     const struct openvpn_sockaddr *local_addr,

+                     const struct openvpn_sockaddr *remote_addr)

+{

+}

+

 #endif

+

+void

+management_sleep(const int n)

+{

+}

new file mode 100644

@@ -0,0 +1,126 @@

+/*

+ *  OpenVPN -- An application to securely tunnel IP networks

+ *             over a single UDP port, with support for SSL/TLS-based

+ *             session authentication and key exchange,

+ *             packet encryption, packet authentication, and

+ *             packet compression.

+ *

+ *  Copyright (C) 2021-2025 Arne Schwabe <arne@rfc2549.org>

+ *

+ *  This program is free software; you can redistribute it and/or modify

+ *  it under the terms of the GNU General Public License version 2

+ *  as published by the Free Software Foundation.

+ *

+ *  This program is distributed in the hope that it will be useful,

+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of

+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

+ *  GNU General Public License for more details.

+ *

+ *  You should have received a copy of the GNU General Public License along

+ *  with this program; if not, see <https://www.gnu.org/licenses/>.

+ */

+

+#ifdef HAVE_CONFIG_H

+#include "config.h"

+#endif

+

+#include "syshead.h"

+

+#include <stdio.h>

+#include <stdlib.h>

+#include <stdarg.h>

+#include <string.h>

+#include <setjmp.h>

+#include <cmocka.h>

+

+#include "socket.h"

+#include "win32.h"

+

+/* stubs for some unused functions instead of pulling in too many dependencies */

+struct signal_info siginfo_static; /* GLOBAL */

+

+int

+signal_reset(struct signal_info *si, int signum)

+{

+    assert_true(0);

+    return 0;

+}

+

+#ifdef _WIN32

+struct win32_signal win32_signal; /* GLOBAL */

+

+int

+win32_signal_get(struct win32_signal *ws)

+{

+    assert_true(0);

+    return 0;

+}

+#endif

+

+int

+parse_line(const char *line, char **p, const int n, const char *file, const int line_num,

+           int msglevel, struct gc_arena *gc)

+{

+    assert_true(0);

+    return 0;

+}

+

+static void

+test_add_in6_addr_tc(const char *orig_str, uint32_t add, const char *expect_str)

+{

+    struct in6_addr orig, result, expected;

+    struct gc_arena gc = gc_new();

+    assert_int_equal(inet_pton(AF_INET6, orig_str, &orig), 1);

+    assert_int_equal(inet_pton(AF_INET6, expect_str, &expected), 1);

+    result = add_in6_addr(orig, add);

+    const char *result_str = print_in6_addr(result, 0, &gc);

+    assert_string_equal(result_str, expect_str);

+    assert_memory_equal(&result, &expected, sizeof(struct in6_addr));

+    gc_free(&gc);

+}

+

+static bool

+check_mapped_ipv4_address(void)

+{

+    struct gc_arena gc = gc_new();

+    const char *ipv4_output = "::255.255.255.255";

+    struct in6_addr addr;

+    assert_int_equal(inet_pton(AF_INET6, ipv4_output, &addr), 1);

+    const char *test_output = print_in6_addr(addr, 0, &gc);

+    bool ret = strcmp(test_output, ipv4_output) == 0;

+    gc_free(&gc);

+    return ret;

+}

+

+static void

+test_add_in6_addr(void **state)

+{

+    /* Note that some of the result strings need to account for

+       print_in6_addr formatting the addresses potentially as IPv4 */

+    bool mapped_ipv4 = check_mapped_ipv4_address();

+    test_add_in6_addr_tc("::", 1, "::1");

+    test_add_in6_addr_tc("::ff", 1, "::100");

+    test_add_in6_addr_tc("::ffff", 1, mapped_ipv4 ? "::0.1.0.0" : "::1:0");

+    test_add_in6_addr_tc("ffff::ffff", 1, "ffff::1:0");

+    test_add_in6_addr_tc("::ffff:ffff", 1, "::1:0:0");

+    test_add_in6_addr_tc("ffff:ffff:ffff:ffff:ffff:ffff:ffff:ffff", 1, "::");

+    test_add_in6_addr_tc("ffff:ffff:ffff:ffff:ffff:ffff:ffff:ffff", 2, "::1");

+

+    test_add_in6_addr_tc("::", UINT32_MAX, mapped_ipv4 ? "::255.255.255.255" : "::ffff:ffff");

+    test_add_in6_addr_tc("::1", UINT32_MAX, "::1:0:0");

+    test_add_in6_addr_tc("::ffff", UINT32_MAX, "::1:0:fffe");

+    test_add_in6_addr_tc("ffff::ffff", UINT32_MAX, "ffff::1:0:fffe");

+    test_add_in6_addr_tc("::ffff:ffff", UINT32_MAX, "::1:ffff:fffe");

+    test_add_in6_addr_tc("ffff:ffff:ffff:ffff:ffff:ffff:ffff:ffff", UINT32_MAX,

+                         mapped_ipv4 ? "::255.255.255.254" : "::ffff:fffe");

+}

+

+const struct CMUnitTest socket_tests[] = {

+    cmocka_unit_test(test_add_in6_addr)

+};

+

+int

+main(void)

+{

+    return cmocka_run_group_tests(socket_tests, NULL, NULL);

+}