Function sctp_compute_hashkey

freebsd/netinet/sctp_auth.c:401–454

* generate the concatenated keying material based on the two keys and the * shared key (if available). draft-ietf-tsvwg-auth specifies the specific * order for concatenation */

 * order for concatenation
 */
sctp_key_t *
sctp_compute_hashkey(sctp_key_t *key1, sctp_key_t *key2, sctp_key_t *shared)
{
	uint32_t keylen;
	sctp_key_t *new_key;
	uint8_t *key_ptr;

	keylen = sctp_get_keylen(key1) + sctp_get_keylen(key2) +
	    sctp_get_keylen(shared);

	if (keylen > 0) {
		/* get space for the new key */
		new_key = sctp_alloc_key(keylen);
		if (new_key == NULL) {
			/* out of memory */
			return (NULL);
		}
		new_key->keylen = keylen;
		key_ptr = new_key->key;
	} else {
		/* all keys empty/null?! */
		return (NULL);
	}

	/* concatenate the keys */
	if (sctp_compare_key(key1, key2) <= 0) {
		/* key is shared + key1 + key2 */
		if (sctp_get_keylen(shared)) {
			memcpy(key_ptr, shared->key, shared->keylen);
			key_ptr += shared->keylen;
		}
		if (sctp_get_keylen(key1)) {
			memcpy(key_ptr, key1->key, key1->keylen);
			key_ptr += key1->keylen;
		}
		if (sctp_get_keylen(key2)) {
			memcpy(key_ptr, key2->key, key2->keylen);
		}
	} else {
		/* key is shared + key2 + key1 */
		if (sctp_get_keylen(shared)) {
			memcpy(key_ptr, shared->key, shared->keylen);
			key_ptr += shared->keylen;
		}
		if (sctp_get_keylen(key2)) {
			memcpy(key_ptr, key2->key, key2->keylen);
			key_ptr += key2->keylen;
		}
		if (sctp_get_keylen(key1)) {
			memcpy(key_ptr, key1->key, key1->keylen);
		}
	}
	return (new_key);
}

sctp_sharedkey_t *
sctp_alloc_sharedkey(void)