identification: Add hash() method

Compared to hashing the encoding we can ignore string types of RDNs when
hashing DNs, making hash() compatible to equals() that does the same.

Fixes #991.

src/libstrongswan/utils/identification.c

@@ -1,5 +1,5 @@
 /*
- * Copyright (C) 2009-2012 Tobias Brunner
+ * Copyright (C) 2009-2015 Tobias Brunner
  * Copyright (C) 2005-2009 Martin Willi
  * Copyright (C) 2005 Jan Hutter
  * Hochschule fuer Technik Rapperswil
@@ -579,6 +579,19 @@ METHOD(identification_t, contains_wildcards_memchr, bool,
 	return memchr(this->encoded.ptr, '*', this->encoded.len) != NULL;
 }
 
+METHOD(identification_t, hash_binary, u_int,
+	private_identification_t *this, u_int inc)
+{
+	u_int hash;
+
+	hash = chunk_hash_inc(chunk_from_thing(this->type), inc);
+	if (this->type != ID_ANY)
+	{
+		hash = chunk_hash_inc(this->encoded, hash);
+	}
+	return hash;
+}
+
 METHOD(identification_t, equals_binary, bool,
 	private_identification_t *this, identification_t *other)
 {
@@ -687,6 +700,24 @@ METHOD(identification_t, equals_dn, bool,
 	return compare_dn(this->encoded, other->get_encoding(other), NULL);
 }
 
+METHOD(identification_t, hash_dn, u_int,
+	private_identification_t *this, u_int inc)
+{
+	enumerator_t *rdns;
+	chunk_t oid, data;
+	u_char type;
+	u_int hash;
+
+	hash = chunk_hash_inc(chunk_from_thing(this->type), inc);
+	rdns = create_rdn_enumerator(this->encoded);
+	while (rdns->enumerate(rdns, &oid, &type, &data))
+	{
+		hash = chunk_hash_inc(data, chunk_hash_inc(oid, hash));
+	}
+	rdns->destroy(rdns);
+	return hash;
+}
+
 METHOD(identification_t, equals_strcasecmp,  bool,
 	private_identification_t *this, identification_t *other)
 {
@@ -903,6 +934,7 @@ static private_identification_t *identification_create(id_type_t type)
 	switch (type)
 	{
 		case ID_ANY:
+			this->public.hash = _hash_binary;
 			this->public.matches = _matches_any;
 			this->public.equals = _equals_binary;
 			this->public.contains_wildcards = return_true;
@@ -910,16 +942,19 @@ static private_identification_t *identification_create(id_type_t type)
 		case ID_FQDN:
 		case ID_RFC822_ADDR:
 		case ID_USER_ID:
+			this->public.hash = _hash_binary;
 			this->public.matches = _matches_string;
 			this->public.equals = _equals_strcasecmp;
 			this->public.contains_wildcards = _contains_wildcards_memchr;
 			break;
 		case ID_DER_ASN1_DN:
+			this->public.hash = _hash_dn;
 			this->public.equals = _equals_dn;
 			this->public.matches = _matches_dn;
 			this->public.contains_wildcards = _contains_wildcards_dn;
 			break;
 		default:
+			this->public.hash = _hash_binary;
 			this->public.equals = _equals_binary;
 			this->public.matches = _matches_binary;
 			this->public.contains_wildcards = return_false;

src/libstrongswan/utils/identification.h

@@ -1,5 +1,5 @@
 /*
- * Copyright (C) 2009 Tobias Brunner
+ * Copyright (C) 2009-2015 Tobias Brunner
  * Copyright (C) 2005-2009 Martin Willi
  * Copyright (C) 2005 Jan Hutter
  * Hochschule fuer Technik Rapperswil
@@ -218,6 +218,14 @@ struct identification_t {
 	 */
 	id_type_t (*get_type) (identification_t *this);
 
+	/**
+	 * Create a hash value for this identification_t object.
+	 *
+	 * @param inc		optional value for incremental hashing
+	 * @return			hash value
+	 */
+	u_int (*hash) (identification_t *this, u_int inc);
+
 	/**
 	 * Check if two identification_t objects are equal.
 	 *