1 files changed, 76 insertions, 0 deletions
diff --git a/dnsstub/dns_dfd.c b/dnsstub/dns_dfd.c
new file mode 100644
index 0000000..756a1f8
--- /dev/null
+++ b/dnsstub/dns_dfd.c
@@ -0,0 +1,76 @@
+#include "error.h"
+#include "alloc.h"
+#include "byte.h"
+#include "dnsresolv.h"
+
+/**
+	@file dns_dfd.c
+	@author djb
+	@source ucspi-tcp
+	@brief domain name qualification (domain from dot)
+*/
+
+int dns_domain_fromdot(char **out,const char *buf,unsigned int n)
+{
+  char label[63];
+  unsigned int labellen = 0; /* <= sizeof label */
+  char name[255];
+  unsigned int namelen = 0; /* <= sizeof name */
+  char ch;
+  char *x;
+
+  errno = EPROTO;
+
+  for (;;) {
+    if (!n) break;
+    ch = *buf++; --n;
+    if (ch == '.') {
+      if (labellen) {
+        if (namelen + labellen + 1 > sizeof(name)) return 0;
+        name[namelen++] = labellen;
+        byte_copy(name + namelen,labellen,label);
+        namelen += labellen;
+        labellen = 0;
+      }
+      continue;
+    }
+    if (ch == '\\') {					             // octal -> decimal
+      if (!n) break;
+      ch = *buf++; --n;
+      if ((ch >= '0') && (ch <= '7')) {
+        ch -= '0';
+        if (n && (*buf >= '0') && (*buf <= '7')) {
+          ch <<= 3;
+          ch += *buf - '0';
+          ++buf; --n;
+          if (n && (*buf >= '0') && (*buf <= '7')) {
+            ch <<= 3;
+            ch += *buf - '0';
+            ++buf; --n;
+          }
+        }
+      }
+    }
+    if (labellen >= sizeof(label)) return 0;
+    label[labellen++] = ch;
+  }
+
+  if (labellen) {
+    if (namelen + labellen + 1 > sizeof(name)) return 0;
+    name[namelen++] = labellen;
+    byte_copy(name + namelen,labellen,label);
+    namelen += labellen;
+    labellen = 0;
+  }
+
+  if (namelen + 1 > sizeof(name)) return 0;
+  name[namelen++] = 0;
+
+  x = alloc(namelen);
+  if (!x) return DNS_MEM;
+  byte_copy(x,namelen,name);
+
+  if (*out) alloc_free(*out);
+  *out = x;
+  return 1;
+}