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henrike@webrtc.orga7b98182014-02-21 15:51:43 +00001/*
2 * libjingle
3 * Copyright 2014 Google Inc.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions are met:
7 *
8 * 1. Redistributions of source code must retain the above copyright notice,
9 * this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright notice,
11 * this list of conditions and the following disclaimer in the documentation
12 * and/or other materials provided with the distribution.
13 * 3. The name of the author may not be used to endorse or promote products
14 * derived from this software without specific prior written permission.
15 *
16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
17 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
18 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO
19 * EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
20 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
21 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
22 * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
23 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
24 * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
25 * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
26 */
27
28#ifndef TALK_SESSION_MEDIA_EXTERNAL_HMAC_H_
29#define TALK_SESSION_MEDIA_EXTERNAL_HMAC_H_
30
31// External libsrtp HMAC auth module which implements methods defined in
32// auth_type_t.
33// The default auth module will be replaced only when the ENABLE_EXTERNAL_AUTH
34// flag is enabled. This allows us to access to authentication keys,
35// as the default auth implementation doesn't provide access and avoids
36// hashing each packet twice.
37
38// How will libsrtp select this module?
39// Libsrtp defines authentication function types identified by an unsigned
40// integer, e.g. HMAC_SHA1 is 3. Using authentication ids, the application
41// can plug any desired authentication modules into libsrtp.
42// libsrtp also provides a mechanism to select different auth functions for
43// individual streams. This can be done by setting the right value in
44// the auth_type of srtp_policy_t. The application must first register auth
45// functions and the corresponding authentication id using
46// crypto_kernel_replace_auth_type function.
47#if defined(HAVE_SRTP) && defined(ENABLE_EXTERNAL_AUTH)
48
henrike@webrtc.org2d213e42014-03-06 18:51:21 +000049#include "talk/base/basictypes.h"
henrike@webrtc.orga7b98182014-02-21 15:51:43 +000050#ifdef SRTP_RELATIVE_PATH
henrike@webrtc.org2d213e42014-03-06 18:51:21 +000051#include "auth.h" // NOLINT
henrike@webrtc.orga7b98182014-02-21 15:51:43 +000052#else
henrike@webrtc.org2d213e42014-03-06 18:51:21 +000053#include "third_party/libsrtp/crypto/include/auth.h"
henrike@webrtc.orga7b98182014-02-21 15:51:43 +000054#endif // SRTP_RELATIVE_PATH
55
56#define EXTERNAL_HMAC_SHA1 HMAC_SHA1 + 1
57#define HMAC_KEY_LENGTH 20
58
59// The HMAC context structure used to store authentication keys.
60// The pointer to the key will be allocated in the external_hmac_init function.
61// This pointer is owned by srtp_t in a template context.
62typedef struct {
henrike@webrtc.org2d213e42014-03-06 18:51:21 +000063 uint8 key[HMAC_KEY_LENGTH];
henrike@webrtc.orga7b98182014-02-21 15:51:43 +000064 int key_length;
65} external_hmac_ctx_t;
66
67err_status_t
68external_hmac_alloc(auth_t** a, int key_len, int out_len);
69
70err_status_t
71external_hmac_dealloc(auth_t* a);
72
73err_status_t
74external_hmac_init(external_hmac_ctx_t* state,
75 const uint8_t* key, int key_len);
76
77err_status_t
78external_hmac_start(external_hmac_ctx_t* state);
79
80err_status_t
81external_hmac_update(external_hmac_ctx_t* state, const uint8_t* message,
82 int msg_octets);
83
84err_status_t
85external_hmac_compute(external_hmac_ctx_t* state, const void* message,
86 int msg_octets, int tag_len, uint8_t* result);
87
88err_status_t
89external_crypto_init();
90
91#endif // defined(HAVE_SRTP) && defined(ENABLE_EXTERNAL_AUTH)
92#endif // TALK_SESSION_MEDIA_EXTERNAL_HMAC_H_