dns: implement tcp fallback in __res_msend query core

[musl] / src / network / res_query.c

diff --git a/src/network/res_query.c b/src/network/res_query.c
index 33543dc..506dc23 100644 (file)
--- a/src/network/res_query.c
+++ b/src/network/res_query.c
@@ -1,13 +1,26 @@
+#define _BSD_SOURCE
 #include <resolv.h>
 #include <netdb.h>
-#include "libc.h"
 
 int res_query(const char *name, int class, int type, unsigned char *dest, int len)
 {
        unsigned char q[280];
        int ql = __res_mkquery(0, name, class, type, 0, 0, 0, q, sizeof q);
        if (ql < 0) return ql;
-       return __res_send(q, ql, dest, len);
+       int r = __res_send(q, ql, dest, len);
+       if (r<12) {
+               h_errno = TRY_AGAIN;
+               return -1;
+       }
+       if ((dest[3] & 15) == 3) {
+               h_errno = HOST_NOT_FOUND;
+               return -1;
+       }
+       if ((dest[3] & 15) == 0 && !dest[6] && !dest[7]) {
+               h_errno = NO_DATA;
+               return -1;
+       }
+       return r;
 }
 
 weak_alias(res_query, res_search);