1 files changed, 74 insertions, 0 deletions
diff --git a/dns_domain.c b/dns_domain.c
new file mode 100644
index 0000000..b931f1d
--- /dev/null
+++ b/dns_domain.c
@@ -0,0 +1,74 @@
+#include "error.h"
+#include "alloc.h"
+#include "case.h"
+#include "byte.h"
+#include "dns.h"
+
+unsigned int dns_domain_length(const char *dn)
+{
+  const char *x;
+  unsigned char c;
+
+  x = dn;
+  while (c = *x++)
+    x += (unsigned int) c;
+  return x - dn;
+}
+
+void dns_domain_free(char **out)
+{
+  if (*out) {
+    alloc_free(*out);
+    *out = 0;
+  }
+}
+
+int dns_domain_copy(char **out,const char *in)
+{
+  unsigned int len;
+  char *x;
+
+  len = dns_domain_length(in);
+  x = alloc(len);
+  if (!x) return 0;
+  byte_copy(x,len,in);
+  if (*out) alloc_free(*out);
+  *out = x;
+  return 1;
+}
+
+int dns_domain_equal(const char *dn1,const char *dn2)
+{
+  unsigned int len;
+
+  len = dns_domain_length(dn1);
+  if (len != dns_domain_length(dn2)) return 0;
+
+  if (case_diffb(dn1,len,dn2)) return 0; /* safe since 63 < 'A' */
+  return 1;
+}
+
+int dns_domain_suffix(const char *big,const char *little)
+{
+  unsigned char c;
+
+  for (;;) {
+    if (dns_domain_equal(big,little)) return 1;
+    c = *big++;
+    if (!c) return 0;
+    big += c;
+  }
+}
+
+unsigned int dns_domain_suffixpos(const char *big,const char *little)
+{
+  const char *orig = big;
+  unsigned char c;
+
+  for (;;) {
+    if (dns_domain_equal(big,little)) return big - orig;
+    c = *big++;
+    if (!c) return 0;
+    big += c;
+  }
+}