// Copyright (c) 2011 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
// Written in NSPR style to also be suitable for adding to the NSS demo suite
#ifndef __MEMIO_H
#define __MEMIO_H
#include <stddef.h>
#ifdef __cplusplus
extern "C" {
#endif
#include "prio.h"
/* Opaque structure. Really just a more typesafe alias for PRFilePrivate. */
struct memio_Private;
typedef struct memio_Private memio_Private;
/*----------------------------------------------------------------------
NSPR I/O layer that terminates in a pair of circular buffers
rather than talking to the real network.
To use this with NSS:
1) call memio_CreateIOLayer to create a fake NSPR socket
2) call SSL_ImportFD to ssl-ify the socket
3) Do your own networking calls to set up a TCP connection
4) call memio_SetPeerName to tell NSS about the other end of the connection
5) While at the same time doing plaintext nonblocking NSPR I/O as
usual to the nspr file descriptor returned by SSL_ImportFD,
your app must shuttle encrypted data between
the real network and memio's network buffers.
memio_GetReadParams/memio_PutReadResult
are the hooks you need to pump data into memio's input buffer,
and memio_GetWriteParams/memio_PutWriteResult
are the hooks you need to pump data out of memio's output buffer.
----------------------------------------------------------------------*/
/* Create the I/O layer and its two circular buffers. */
PRFileDesc *memio_CreateIOLayer(int readbufsize, int writebufsize);
/* Must call before trying to make an ssl connection */
void memio_SetPeerName(PRFileDesc *fd, const PRNetAddr *peername);
/* Return a private pointer needed by the following
* four functions. (We could have passed a PRFileDesc to
* them, but that would be slower. Better for the caller
* to grab the pointer once and cache it.
* This may be a premature optimization.)
*/
memio_Private *memio_GetSecret(PRFileDesc *fd);
/* Ask memio how many bytes were requested by a higher layer if the
* last attempt to read data resulted in PR_WOULD_BLOCK_ERROR, due to the
* transport buffer being empty. If the last attempt to read data from the
* memio did not result in PR_WOULD_BLOCK_ERROR, returns 0.
*/
int memio_GetReadRequest(memio_Private *secret);
/* Ask memio where to put bytes from the network, and how many it can handle.
* Returns bytes available to write, or 0 if none available.
* Puts current buffer position into *buf.
*/
int memio_GetReadParams(memio_Private *secret, char **buf);
/* Ask memio how many bytes are contained in the internal buffer.
* Returns bytes available to read, or 0 if none available.
*/
int memio_GetReadableBufferSize(memio_Private *secret);
/* Tell memio how many bytes were read from the network.
* If bytes_read is 0, causes EOF to be reported to
* NSS after it reads the last byte from the circular buffer.
* If bytes_read is < 0, it is treated as an NSPR error code.
* See nspr/pr/src/md/unix/unix_errors.c for how to
* map from Unix errors to NSPR error codes.
* On EWOULDBLOCK or the equivalent, don't call this function.
*/
void memio_PutReadResult(memio_Private *secret, int bytes_read);
/* Ask memio what data it has to send to the network.
* Returns up to two buffers of data by writing the positions and lengths into
* |buf1|, |len1| and |buf2|, |len2|.
*/
void memio_GetWriteParams(memio_Private *secret,
const char **buf1, unsigned int *len1,
const char **buf2, unsigned int *len2);
/* Tell memio how many bytes were sent to the network.
* If bytes_written is < 0, it is treated as an NSPR error code.
* See nspr/pr/src/md/unix/unix_errors.c for how to
* map from Unix errors to NSPR error codes.
* On EWOULDBLOCK or the equivalent, don't call this function.
*/
void memio_PutWriteResult(memio_Private *secret, int bytes_written);
#ifdef __cplusplus
}
#endif
#endif