From 5fb4cd8a9c1e4d322b4f2758378722ebc4856840 Mon Sep 17 00:00:00 2001
From: Jon Shallow <supjps-libcoap@jpshallow.com>
Date: Sat, 27 Dec 2025 12:18:21 +0000
Subject: [PATCH] getifaddrs(): Check for function support

---
 CMakeLists.txt         |  1 +
 cmake_coap_config.h.in |  3 +++
 configure.ac           |  2 +-
 src/coap_address.c     | 12 ++++++------
 4 files changed, 11 insertions(+), 7 deletions(-)

diff --git a/CMakeLists.txt b/CMakeLists.txt
index a4509238..f862c103 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -314,6 +314,7 @@ if(MINGW OR WIN32)
   set(CMAKE_REQUIRED_LIBRARIES "")
 endif()
 check_function_exists(getaddrinfo HAVE_GETADDRINFO)
+check_function_exists(getifaddrs HAVE_GETIFADDRS)
 check_function_exists(strnlen HAVE_STRNLEN)
 check_function_exists(strrchr HAVE_STRRCHR)
 check_function_exists(getrandom HAVE_GETRANDOM)
diff --git a/cmake_coap_config.h.in b/cmake_coap_config.h.in
index 4c1895a5..c134572a 100644
--- a/cmake_coap_config.h.in
+++ b/cmake_coap_config.h.in
@@ -43,6 +43,9 @@
 /* Define to 1 if you have the `getaddrinfo' function. */
 #cmakedefine HAVE_GETADDRINFO @HAVE_GETADDRINFO@
 
+/* Define to 1 if you have the `getifaddrs' function. */
+#cmakedefine HAVE_GETIFADDRS @HAVE_GETIFADDRS@
+
 /* Define to 1 if you have the `getrandom' function. */
 #cmakedefine HAVE_GETRANDOM @HAVE_GETRANDOM@
 
diff --git a/configure.ac b/configure.ac
index a8715b8f..9a1c0bf8 100644
--- a/configure.ac
+++ b/configure.ac
@@ -1242,7 +1242,7 @@ AC_TYPE_SIZE_T
 AC_TYPE_SSIZE_T
 
 # Checks for library functions.
-AC_CHECK_FUNCS([memset select socket strcasecmp strrchr getaddrinfo \
+AC_CHECK_FUNCS([memset select socket strcasecmp strrchr getaddrinfo getifaddrs \
                 strnlen malloc pthread_mutex_lock getrandom random if_nametoindex])
 
 # Check if -lsocket -lnsl is required (specifically Solaris)
diff --git a/src/coap_address.c b/src/coap_address.c
index 35215832..845a9dec 100644
--- a/src/coap_address.c
+++ b/src/coap_address.c
@@ -180,20 +180,20 @@ coap_is_mcast(const coap_address_t *a) {
 #define COAP_BCST_REFRESH_SECS 30
 #endif /* COAP_BCST_REFRESH_SECS */
 
-#if (COAP_IPV4_SUPPORT && defined(HAVE_IFADDRS_H) && !defined(__ZEPHYR__)) || defined(_WIN32)
+#if COAP_IPV4_SUPPORT && !defined(__ZEPHYR__) && (defined(HAVE_GETIFADDRS) || defined(_WIN32))
 static int bcst_cnt = -1;
 static coap_tick_t last_refresh;
 static struct in_addr b_ipv4[COAP_BCST_CNT];
-#endif /* (COAP_IPV4_SUPPORT && HAVE_IFADDRS_H && !defined(__ZEPHYR__)) || defined(_WIN32) */
+#endif /* COAP_IPV4_SUPPORT && !defined(__ZEPHYR__) && (defined(HAVE_GETIFADDRS) || defined(_WIN32)) */
 
 int
 coap_is_bcast(const coap_address_t *a) {
 #if COAP_IPV4_SUPPORT
   struct in_addr ipv4;
-#if defined(HAVE_IFADDRS_H) && !defined(__ZEPHYR__)
+#if defined(HAVE_GETIFADDRS) && !defined(__ZEPHYR__)
   int i;
   coap_tick_t now;
-#endif /* HAVE_IFADDRS_H && !defined(__ZEPHYR__) */
+#endif /* HAVE_GETIFADDRS && !defined(__ZEPHYR__) */
 #endif /* COAP_IPV4_SUPPORT */
 
   if (!a)
@@ -226,7 +226,7 @@ coap_is_bcast(const coap_address_t *a) {
   if (ipv4.s_addr == INADDR_BROADCAST)
     return 1;
 
-#if defined(HAVE_IFADDRS_H) && !defined(__ZEPHYR__) && !defined(_WIN32)
+#if defined(HAVE_GETIFADDRS) && !defined(__ZEPHYR__)
   coap_ticks(&now);
   if (bcst_cnt == -1 ||
       (now - last_refresh) > (COAP_BCST_REFRESH_SECS * COAP_TICKS_PER_SECOND)) {
@@ -268,7 +268,7 @@ coap_is_bcast(const coap_address_t *a) {
     if (ipv4.s_addr == b_ipv4[i].s_addr)
       return 1;
   }
-#endif /* HAVE_IFADDRS_H && !defined(__ZEPHYR__) && !defined(_WIN32) */
+#endif /* HAVE_GETIFADDRS && !defined(__ZEPHYR__) */
 
 #if defined(_WIN32)