1 files changed, 50 insertions, 0 deletions
diff --git a/force-ip-protocol-ipv4-or-ipv6.c b/force-ip-protocol-ipv4-or-ipv6.c
new file mode 100644
index 0000000..bd366ff
--- /dev/null
+++ b/force-ip-protocol-ipv4-or-ipv6.c
@@ -0,0 +1,50 @@
+/*
+   force-ip-protocol
+   Copyright (C) 2023 Thorsten Alteholz
+
+   This program is free software: you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation, version 2 of the License.
+
+   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 <http://www.gnu.org/licenses/>.
+
+   usage: LD_PRELOAD=/path/to/library.so program args ...
+ */
+
+#include <config.h>
+
+#ifdef HAVE_SYS_SOCKET_H
+ #include <sys/socket.h>
+#endif
+
+#ifdef HAVE_NETDB_H
+ #include <netdb.h>
+#endif
+
+#ifdef HAVE_DLFCN_H
+ #include <dlfcn.h>
+#endif
+
+int getaddrinfo(const char *hostname, const char *servname,
+		const struct addrinfo *hints, struct addrinfo **res)
+{
+	int (*getaddrinfo_org)();
+	struct addrinfo *hints2 = (struct addrinfo *) hints;
+
+	getaddrinfo_org = dlsym(RTLD_NEXT, "getaddrinfo");
+#if defined USE_IPV4
+	hints2->ai_family = PF_INET;
+#elif defined USE_IPV6
+	hints2->ai_family = PF_INET6;
+#else
+#error You must define either USE_IPV4 or USE_IPV6.
+#endif
+
+	return (getaddrinfo_org(hostname, servname, hints2, res));
+}