Avoid UB from socket.h macros

Only when building with UBSAN for now.

Author: iluuu1994

ext/sockets/conversions.c

@@ -60,6 +60,14 @@ struct _WSAMSG {
 #define MAX_USER_BUFF_SIZE ((size_t)(100*1024*1024))
 #define DEFAULT_BUFF_SIZE 8192
 
+/* The CMSG_DATA macro does pointer arithmetics on NULL which triggers errors in the Clang UBSAN build */
+#ifdef __linux__
+# if __has_feature(address_sanitizer)
+#  undef CMSG_DATA
+#  define CMSG_DATA(cmsg) ((unsigned char *) ((uintptr_t) (cmsg) + sizeof(struct cmsghdr)))
+# endif
+#endif
+
 struct _ser_context {
 	HashTable		params; /* stores pointers; has to be first */
 	struct err_s	err;

ext/sockets/sockets.c

@@ -76,8 +76,12 @@
 
 ZEND_DECLARE_MODULE_GLOBALS(sockets)
 
-#ifndef SUN_LEN
-#define SUN_LEN(su) (sizeof(*(su)) - sizeof((su)->sun_path) + strlen((su)->sun_path))
+/* The SUN_LEN macro does pointer arithmetics on NULL which triggers errors in the Clang UBSAN build */
+#ifdef __linux__
+# if __has_feature(address_sanitizer)
+#  undef SUN_LEN
+#  define SUN_LEN(su) (sizeof(*(su)) - sizeof((su)->sun_path) + strlen((su)->sun_path))
+# endif
 #endif
 
 #ifndef PF_INET