1// Copyright (c) 2008 The Chromium Authors. All rights reserved.
2// Use of this source code is governed by a BSD-style license that can be
3// found in the LICENSE file.
4// Written in NSPR style to also be suitable for adding to the NSS demo suite
5
6#ifndef __MEMIO_H
7#define __MEMIO_H
8#pragma once
9
10#include <stddef.h>
11
12#ifdef __cplusplus
13extern "C" {
14#endif
15
16#include "prio.h"
17
18/* Opaque structure.  Really just a more typesafe alias for PRFilePrivate. */
19struct memio_Private;
20typedef struct memio_Private memio_Private;
21
22/*----------------------------------------------------------------------
23 NSPR I/O layer that terminates in a pair of circular buffers
24 rather than talking to the real network.
25 To use this with NSS:
26 1) call memio_CreateIOLayer to create a fake NSPR socket
27 2) call SSL_ImportFD to ssl-ify the socket
28 3) Do your own networking calls to set up a TCP connection
29 4) call memio_SetPeerName to tell NSS about the other end of the connection
30 5) While at the same time doing plaintext nonblocking NSPR I/O as
31    usual to the nspr file descriptor returned by SSL_ImportFD,
32    your app must shuttle encrypted data between
33    the real network and memio's network buffers.
34    memio_GetReadParams/memio_PutReadResult
35    are the hooks you need to pump data into memio's input buffer,
36    and memio_GetWriteParams/memio_PutWriteResult
37    are the hooks you need to pump data out of memio's output buffer.
38----------------------------------------------------------------------*/
39
40/* Create the I/O layer and its two circular buffers. */
41PRFileDesc *memio_CreateIOLayer(int bufsize);
42
43/* Must call before trying to make an ssl connection */
44void memio_SetPeerName(PRFileDesc *fd, const PRNetAddr *peername);
45
46/* Return a private pointer needed by the following
47 * four functions.  (We could have passed a PRFileDesc to
48 * them, but that would be slower.  Better for the caller
49 * to grab the pointer once and cache it.
50 * This may be a premature optimization.)
51 */
52memio_Private *memio_GetSecret(PRFileDesc *fd);
53
54/* Ask memio where to put bytes from the network, and how many it can handle.
55 * Returns bytes available to write, or 0 if none available.
56 * Puts current buffer position into *buf.
57 */
58int memio_GetReadParams(memio_Private *secret, char **buf);
59
60/* Tell memio how many bytes were read from the network.
61 * If bytes_read is 0, causes EOF to be reported to
62 * NSS after it reads the last byte from the circular buffer.
63 * If bytes_read is < 0, it is treated as an NSPR error code.
64 * See nspr/pr/src/md/unix/unix_errors.c for how to
65 * map from Unix errors to NSPR error codes.
66 * On EWOULDBLOCK or the equivalent, don't call this function.
67 */
68void memio_PutReadResult(memio_Private *secret, int bytes_read);
69
70/* Ask memio what data it has to send to the network.
71 * Returns up to two buffers of data by writing the positions and lengths into
72 * |buf1|, |len1| and |buf2|, |len2|.
73 */
74void memio_GetWriteParams(memio_Private *secret,
75                          const char **buf1, unsigned int *len1,
76                          const char **buf2, unsigned int *len2);
77
78/* Tell memio how many bytes were sent to the network.
79 * If bytes_written is < 0, it is treated as an NSPR error code.
80 * See nspr/pr/src/md/unix/unix_errors.c for how to
81 * map from Unix errors to NSPR error codes.
82 * On EWOULDBLOCK or the equivalent, don't call this function.
83 */
84void memio_PutWriteResult(memio_Private *secret, int bytes_written);
85
86
87#ifdef __cplusplus
88}
89#endif
90
91#endif
92