1 // Copyright (c) 2011 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 9 #include <stddef.h> 10 11 #ifdef __cplusplus 12 extern "C" { 13 #endif 14 15 #include "prio.h" 16 17 /* Opaque structure. Really just a more typesafe alias for PRFilePrivate. */ 18 struct memio_Private; 19 typedef struct memio_Private memio_Private; 20 21 /*---------------------------------------------------------------------- 22 NSPR I/O layer that terminates in a pair of circular buffers 23 rather than talking to the real network. 24 To use this with NSS: 25 1) call memio_CreateIOLayer to create a fake NSPR socket 26 2) call SSL_ImportFD to ssl-ify the socket 27 3) Do your own networking calls to set up a TCP connection 28 4) call memio_SetPeerName to tell NSS about the other end of the connection 29 5) While at the same time doing plaintext nonblocking NSPR I/O as 30 usual to the nspr file descriptor returned by SSL_ImportFD, 31 your app must shuttle encrypted data between 32 the real network and memio's network buffers. 33 memio_GetReadParams/memio_PutReadResult 34 are the hooks you need to pump data into memio's input buffer, 35 and memio_GetWriteParams/memio_PutWriteResult 36 are the hooks you need to pump data out of memio's output buffer. 37 ----------------------------------------------------------------------*/ 38 39 /* Create the I/O layer and its two circular buffers. */ 40 PRFileDesc *memio_CreateIOLayer(int readbufsize, int writebufsize); 41 42 /* Must call before trying to make an ssl connection */ 43 void memio_SetPeerName(PRFileDesc *fd, const PRNetAddr *peername); 44 45 /* Return a private pointer needed by the following 46 * four functions. (We could have passed a PRFileDesc to 47 * them, but that would be slower. Better for the caller 48 * to grab the pointer once and cache it. 49 * This may be a premature optimization.) 50 */ 51 memio_Private *memio_GetSecret(PRFileDesc *fd); 52 53 /* Ask memio how many bytes were requested by a higher layer if the 54 * last attempt to read data resulted in PR_WOULD_BLOCK_ERROR, due to the 55 * transport buffer being empty. If the last attempt to read data from the 56 * memio did not result in PR_WOULD_BLOCK_ERROR, returns 0. 57 */ 58 int memio_GetReadRequest(memio_Private *secret); 59 60 /* Ask memio where to put bytes from the network, and how many it can handle. 61 * Returns bytes available to write, or 0 if none available. 62 * Puts current buffer position into *buf. 63 */ 64 int memio_GetReadParams(memio_Private *secret, char **buf); 65 66 /* Ask memio how many bytes are contained in the internal buffer. 67 * Returns bytes available to read, or 0 if none available. 68 */ 69 int memio_GetReadableBufferSize(memio_Private *secret); 70 71 /* Tell memio how many bytes were read from the network. 72 * If bytes_read is 0, causes EOF to be reported to 73 * NSS after it reads the last byte from the circular buffer. 74 * If bytes_read is < 0, it is treated as an NSPR error code. 75 * See nspr/pr/src/md/unix/unix_errors.c for how to 76 * map from Unix errors to NSPR error codes. 77 * On EWOULDBLOCK or the equivalent, don't call this function. 78 */ 79 void memio_PutReadResult(memio_Private *secret, int bytes_read); 80 81 /* Ask memio what data it has to send to the network. 82 * Returns up to two buffers of data by writing the positions and lengths into 83 * |buf1|, |len1| and |buf2|, |len2|. 84 */ 85 void memio_GetWriteParams(memio_Private *secret, 86 const char **buf1, unsigned int *len1, 87 const char **buf2, unsigned int *len2); 88 89 /* Tell memio how many bytes were sent to the network. 90 * If bytes_written is < 0, it is treated as an NSPR error code. 91 * See nspr/pr/src/md/unix/unix_errors.c for how to 92 * map from Unix errors to NSPR error codes. 93 * On EWOULDBLOCK or the equivalent, don't call this function. 94 */ 95 void memio_PutWriteResult(memio_Private *secret, int bytes_written); 96 97 #ifdef __cplusplus 98 } 99 #endif 100 101 #endif 102
