Implemented resolver to replace sock_srv_lookup()

tests/res_query_dump.c

@@ -0,0 +1,56 @@
+/* Simple program to dump res_query(3) response. */
+
+#include <netinet/in.h>
+#include <arpa/nameser.h>
+#include <resolv.h>
+
+#include <errno.h>
+#include <stdio.h>
+#include <string.h>
+
+#define STEP 8
+
+int main(int argc, char **argv)
+{
+    unsigned char buf[65536];
+    char fulldomain[2048];
+    char *service = "xmpp-client";
+    char *proto = "tcp";
+    char *domain = NULL;
+    int len;
+    int i;
+    int j;
+
+    if (argc < 2) {
+        fprintf(stderr, "%s: argument missed\n", argc > 0 ? argv[0] : "$0");
+        fprintf(stderr, "Usage: %s <domain>\n", argc > 0 ? argv[0] : "$0");
+        return 1;
+    }
+
+    domain = argv[1];
+    snprintf(fulldomain, sizeof(fulldomain), "_%s._%s.%s",
+             service, proto, domain);
+    errno = 0;
+    len = res_query(fulldomain, C_IN, T_SRV, buf, sizeof(buf));
+
+    if (len < 0) {
+        fprintf(stderr, "res_query(): Error occured (errno=%d)\n", errno);
+    }
+    if (len == 0) {
+        fprintf(stderr, "res_query(): Empty result\n");
+    }
+    if (len > 0) {
+        printf("/* res_query(\"%s\", C_IN, T_SRV, ...) */\n", fulldomain);
+        printf("static const unsigned char data[] = {\n");
+        for (i = 0; i < len; i += STEP) {
+            printf("   ");
+            for (j = i; j < len && j < i + STEP; ++j) {
+                printf(" 0x%02x,", buf[j]);
+            }
+            printf("\n");
+        }
+        printf("};\n");
+    }
+
+    return len <= 0;
+}