Port SSLClientSocket to Linux

net/base/nss_memio.c

+// Copyright (c) 2008 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
+
+/* memio is a simple NSPR I/O layer that lets you decouple NSS from 
+ * the real network.  It's rather like openssl's memory bio,
+ * and is useful when your app absolutely, positively doesn't
+ * want to let NSS do its own networking.
+ */
+
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+
+#include <prerror.h>
+#include <prinit.h>
+#include <prlog.h>
+
+#include "nss_memio.h"
+
+/*--------------- private memio types -----------------------*/
+
+/*----------------------------------------------------------------------
+ Simple private circular buffer class.  Size cannot be changed once allocated.
+----------------------------------------------------------------------*/
+
+struct memio_buffer {
+    int head;     /* where to take next byte out of buf */
+    int tail;     /* where to put next byte into buf */
+    int bufsize;  /* number of bytes allocated to buf */
+    /* TODO(port): error handling is pessimistic right now.
+     * Once an error is set, the socket is considered broken
+     * (PR_WOULD_BLOCK_ERROR not included).
+     */
+    PRErrorCode last_err;
+    char *buf;
+};
+
+
+/* The 'secret' field of a PRFileDesc created by memio_CreateIOLayer points 
+ * to one of these.
+ * In the public header, we use struct memio_Private as a typesafe alias 
+ * for this.  This causes a few ugly typecasts in the private file, but
+ * seems safer.
+ */
+struct PRFilePrivate {
+    /* read requests are satisfied from this buffer */
+    struct memio_buffer readbuf;    
+
+    /* write requests are satisfied from this buffer */
+    struct memio_buffer writebuf;   
+
+    /* SSL needs to know socket peer's name */
+    PRNetAddr peername;             
+
+    /* if set, empty I/O returns EOF instead of EWOULDBLOCK */
+    int eof;
+};
+
+/*--------------- private memio_buffer functions ---------------------*/
+
+/* Forward declarations.  */
+
+/* Allocate a memio_buffer of given size. */
+static void memio_buffer_new(struct memio_buffer *mb, int size);
+
+/* Deallocate a memio_buffer allocated by memio_buffer_new. */
+static void memio_buffer_destroy(struct memio_buffer *mb);
+
+/* How many bytes have been put into the buffer */
+static int memio_buffer_used(const struct memio_buffer *mb);
+
+/* How many bytes can be read out of the buffer without wrapping */
+static int memio_buffer_used_contiguous(const struct memio_buffer *mb);
+
+/* How many bytes can still be put into the buffer */
+static int memio_buffer_unused(const struct memio_buffer *mb);
+
+/* How many bytes can be written into the buffer without wrapping */
+static int memio_buffer_unused_contiguous(const struct memio_buffer *mb);
+
+/* Is buffer completely empty? */
+static int memio_buffer_empty(const struct memio_buffer *mb);
+
+/* Is buffer completely full? */
+static int memio_buffer_full(const struct memio_buffer *mb);
+
+/* Write n bytes into the buffer.  Returns number of bytes written. */
+static int memio_buffer_put(struct memio_buffer *mb, const char *buf, int n);
+
+/* Read n bytes from the buffer.  Returns number of bytes read. */
+static int memio_buffer_get(struct memio_buffer *mb, char *buf, int n);
+
+/* Allocate a memio_buffer of given size. */
+static void memio_buffer_new(struct memio_buffer *mb, int size)
+{
+    mb->head = 0;
+    mb->tail = 0;
+    mb->bufsize = size;
+    mb->buf = malloc(size);
+}
+
+/* Deallocate a memio_buffer allocated by memio_buffer_new. */
+static void memio_buffer_destroy(struct memio_buffer *mb)
+{
+    free(mb->buf);
+    mb->buf = NULL;
+    mb->head = 0;
+    mb->tail = 0;
+}
+
+/* How many bytes have been put into the buffer */
+static int memio_buffer_used(const struct memio_buffer *mb)
+{
+    int n = mb->tail - mb->head;
+    if (n < 0) n += mb->bufsize;
+    return n;
+}
+
+/* How many bytes can be read out of the buffer without wrapping */
+static int memio_buffer_used_contiguous(const struct memio_buffer *mb)
+{ 
+    return (((mb->tail >= mb->head) ? mb->tail : mb->bufsize) - mb->head);
+}
+
+/* How many bytes can still be put into the buffer */
+static int memio_buffer_unused(const struct memio_buffer *mb)
+{
+    return mb->bufsize - memio_buffer_used(mb) - 1;
+}
+
+/* How many bytes can be written into the buffer without wrapping */
+static int memio_buffer_unused_contiguous(const struct memio_buffer *mb)
+{ 
+    if (mb->head > mb->tail) return mb->head - mb->tail - 1;
+    return mb->bufsize - mb->tail - (mb->head == 0);
+}
+
+/* Is buffer completely empty? */
+static int memio_buffer_empty(const struct memio_buffer *mb)
+{
+    return mb->head == mb->tail;
+}
+
+/* Is buffer completely full? */
+static int memio_buffer_full(const struct memio_buffer *mb)
+{
+    return memio_buffer_unused(mb) == 0;
+}
+
+/* Write n bytes into the buffer.  Returns number of bytes written. */
+static int memio_buffer_put(struct memio_buffer *mb, const char *buf, int n)
+{
+    int len;
+    int transferred = 0;
+
+    /* Handle part before wrap */
+    len = PR_MIN(n, memio_buffer_unused_contiguous(mb));
+    if (len > 0) {
+        /* Buffer not full */
+        memcpy(&mb->buf[mb->tail], buf, len);
+        mb->tail += len;
+        if (mb->tail == mb->bufsize)
+            mb->tail = 0;
+        n -= len;
+        buf += len;
+        transferred += len;
+
+        /* Handle part after wrap */
+        len = PR_MIN(n, memio_buffer_unused_contiguous(mb));
+        if (len > 0) {
+            /* Output buffer still not full, input buffer still not empty */
+            memcpy(&mb->buf[mb->tail], buf, len);
+            mb->tail += len;
+            if (mb->tail == mb->bufsize)
+                mb->tail = 0;
+            transferred += len;
+        }
+    }
+
+    return transferred;
+}
+
+
+/* Read n bytes from the buffer.  Returns number of bytes read. */
+static int memio_buffer_get(struct memio_buffer *mb, char *buf, int n)
+{
+    int len;
+    int transferred = 0;
+
+    /* Handle part before wrap */
+    len = PR_MIN(n, memio_buffer_used_contiguous(mb));
+    if (len) {
+        memcpy(buf, &mb->buf[mb->head], len);
+        mb->head += len;
+        if (mb->head == mb->bufsize)
+            mb->head = 0;
+        n -= len;
+        buf += len;
+        transferred += len;
+
+        /* Handle part after wrap */
+        len = PR_MIN(n, memio_buffer_used_contiguous(mb));
+        if (len) {
+            memcpy(buf, &mb->buf[mb->head], len);
+            mb->head += len;
+            if (mb->head == mb->bufsize)
+                mb->head = 0;
+            transferred += len;
+        }
+    }
+
+    return transferred;
+}
+
+/*--------------- private memio functions -----------------------*/
+
+static PRStatus PR_CALLBACK memio_Close(PRFileDesc *fd)
+{
+    struct PRFilePrivate *secret = fd->secret;
+    memio_buffer_destroy(&secret->readbuf);
+    memio_buffer_destroy(&secret->writebuf);
+    free(secret);
+    fd->dtor(fd);
+    return PR_SUCCESS;
+}
+
+static PRStatus PR_CALLBACK memio_Shutdown(PRFileDesc *fd, PRIntn how)
+{
+    /* TODO: pass shutdown status to app somehow */
+    return PR_SUCCESS;
+}
+
+/* If there was a network error in the past taking bytes
+ * out of the buffer, return it to the next call that
+ * tries to read from an empty buffer.
+ */
+static int PR_CALLBACK memio_Recv(PRFileDesc *fd, void *buf, PRInt32 len, 
+                                  PRIntn flags, PRIntervalTime timeout)
+{
+    struct PRFilePrivate *secret;
+    struct memio_buffer *mb;
+    int rv;
+
+    if (flags) {
+        PR_SetError(PR_NOT_IMPLEMENTED_ERROR, 0);
+        return -1;
+    }
+
+    secret = fd->secret;
+    mb = &secret->readbuf;
+    PR_ASSERT(mb->bufsize);
+    rv = memio_buffer_get(mb, buf, len);
+    if (rv == 0 && !secret->eof) {
+        if (mb->last_err)
+            PR_SetError(mb->last_err, 0);
+        else
+            PR_SetError(PR_WOULD_BLOCK_ERROR, 0);
+        return -1;
+    }
+
+    return rv;
+}
+
+static int PR_CALLBACK memio_Read(PRFileDesc *fd, void *buf, PRInt32 len)
+{
+    /* pull bytes from buffer */
+    return memio_Recv(fd, buf, len, 0, PR_INTERVAL_NO_TIMEOUT);
+}
+
+static int PR_CALLBACK memio_Send(PRFileDesc *fd, const void *buf, PRInt32 len,
+                                  PRIntn flags, PRIntervalTime timeout)
+{
+    struct PRFilePrivate *secret;
+    struct memio_buffer *mb;
+    int rv;
+
+    secret = fd->secret;
+    mb = &secret->writebuf;
+    PR_ASSERT(mb->bufsize);
+
+    if (mb->last_err) {
+        PR_SetError(mb->last_err, 0);
+        return -1;
+    }
+    rv = memio_buffer_put(mb, buf, len);
+    if (rv == 0) {
+        PR_SetError(PR_WOULD_BLOCK_ERROR, 0);
+        return -1;
+    }
+    return rv;
+}
+
+static int PR_CALLBACK memio_Write(PRFileDesc *fd, const void *buf, PRInt32 len)
+{
+    /* append bytes to buffer */
+    return memio_Send(fd, buf, len, 0, PR_INTERVAL_NO_TIMEOUT);
+}
+
+static PRStatus PR_CALLBACK memio_GetPeerName(PRFileDesc *fd, PRNetAddr *addr)
+{
+    /* TODO: fail if memio_SetPeerName has not been called */
+    struct PRFilePrivate *secret = fd->secret;
+    *addr = secret->peername;
+    return PR_SUCCESS;
+}
+
+static PRStatus memio_GetSocketOption(PRFileDesc *fd, PRSocketOptionData *data)
+{
+    /*
+     * Even in the original version for real tcp sockets,
+     * PR_SockOpt_Nonblocking is a special case that does not
+     * translate to a getsockopt() call
+     */
+    if (PR_SockOpt_Nonblocking == data->option) {
+        data->value.non_blocking = PR_TRUE;
+        return PR_SUCCESS;
+    }
+    PR_SetError(PR_OPERATION_NOT_SUPPORTED_ERROR, 0);
+    return PR_FAILURE;
+}
+
+/*--------------- private memio data -----------------------*/
+
+/* 
+ * Implement just the bare minimum number of methods needed to make ssl happy.
+ *
+ * Oddly, PR_Recv calls ssl_Recv calls ssl_SocketIsBlocking calls 
+ * PR_GetSocketOption, so we have to provide an implementation of 
+ * PR_GetSocketOption that just says "I'm nonblocking".
+ */
+
+static struct PRIOMethods  memio_layer_methods = {
+    PR_DESC_LAYERED,
+    memio_Close,
+    memio_Read,
+    memio_Write,
+    NULL,
+    NULL,
+    NULL,
+    NULL,
+    NULL,
+    NULL,
+    NULL,
+    NULL,
+    NULL,
+    NULL,
+    NULL,
+    NULL,
+    memio_Shutdown,
+    memio_Recv,
+    memio_Send,
+    NULL,
+    NULL,
+    NULL,
+    NULL,
+    NULL,
+    NULL,
+    memio_GetPeerName,
+    NULL,
+    NULL,
+    memio_GetSocketOption,
+    NULL,
+    NULL,
+    NULL,
+    NULL,
+    NULL,
+    NULL,
+    NULL,
+};
+
+static PRDescIdentity memio_identity = PR_INVALID_IO_LAYER;
+
+static PRStatus memio_InitializeLayerName(void)
+{
+    memio_identity = PR_GetUniqueIdentity("memio");
+    return PR_SUCCESS;
+}
+
+/*--------------- public memio functions -----------------------*/
+
+PRFileDesc *memio_CreateIOLayer(int bufsize)
+{
+    PRFileDesc *fd;
+    struct PRFilePrivate *secret;
+    static PRCallOnceType once;
+
+    PR_CallOnce(&once, memio_InitializeLayerName);
+
+    fd = PR_CreateIOLayerStub(memio_identity, &memio_layer_methods);
+    secret = malloc(sizeof(struct PRFilePrivate));
+    memset(secret, 0, sizeof(*secret));
+
+    memio_buffer_new(&secret->readbuf, bufsize);
+    memio_buffer_new(&secret->writebuf, bufsize);
+    fd->secret = secret;
+    return fd;
+}
+
+void memio_SetPeerName(PRFileDesc *fd, const PRNetAddr *peername)
+{
+    PRFileDesc *memiofd = PR_GetIdentitiesLayer(fd, memio_identity);
+    struct PRFilePrivate *secret =  memiofd->secret;
+    secret->peername = *peername;
+}
+
+memio_Private *memio_GetSecret(PRFileDesc *fd)
+{
+    PRFileDesc *memiofd = PR_GetIdentitiesLayer(fd, memio_identity);
+    struct PRFilePrivate *secret =  memiofd->secret;
+    return (memio_Private *)secret;
+}
+
+int memio_GetReadParams(memio_Private *secret, char **buf)
+{
+    struct memio_buffer* mb = &((PRFilePrivate *)secret)->readbuf;
+    PR_ASSERT(mb->bufsize);
+
+    *buf = &mb->buf[mb->tail];
+    return memio_buffer_unused_contiguous(mb);
+}
+
+void memio_PutReadResult(memio_Private *secret, int bytes_read)
+{
+    struct memio_buffer* mb = &((PRFilePrivate *)secret)->readbuf;
+    PR_ASSERT(mb->bufsize);
+
+    if (bytes_read > 0) {
+        mb->tail += bytes_read;
+        if (mb->tail == mb->bufsize)
+            mb->tail = 0;
+    } else if (bytes_read == 0) {
+        /* Record EOF condition and report to caller when buffer runs dry */
+        ((PRFilePrivate *)secret)->eof = PR_TRUE;
+    } else /* if (bytes_read < 0) */ {
+        mb->last_err = bytes_read;
+    }
+}
+
+int memio_GetWriteParams(memio_Private *secret, const char **buf)
+{
+    struct memio_buffer* mb = &((PRFilePrivate *)secret)->writebuf;
+    PR_ASSERT(mb->bufsize);
+
+    *buf = &mb->buf[mb->head];
+    return memio_buffer_used_contiguous(mb);
+}
+
+void memio_PutWriteResult(memio_Private *secret, int bytes_written)
+{
+    struct memio_buffer* mb = &((PRFilePrivate *)secret)->writebuf;
+    PR_ASSERT(mb->bufsize);
+
+    if (bytes_written > 0) {
+        mb->head += bytes_written;
+        if (mb->head == mb->bufsize)
+            mb->head = 0;
+    } else if (bytes_written < 0) {
+        mb->last_err = bytes_written;
+    }
+}
+
+/*--------------- private memio_buffer self-test -----------------*/
+
+/* Even a trivial unit test is very helpful when doing circular buffers. */
+/*#define TRIVIAL_SELF_TEST*/
+#ifdef TRIVIAL_SELF_TEST
+#include <stdio.h>
+
+#define TEST_BUFLEN 7
+
+#define CHECKEQ(a, b) { \
+    if ((a) != (b)) { \
+        printf("%d != %d, Test failed line %d\n", a, b, __LINE__); \
+        exit(1); \
+    } \
+}
+
+int main()
+{
+    struct memio_buffer mb;
+    char buf[100];
+    int i;
+
+    memio_buffer_new(&mb, TEST_BUFLEN);
+
+    CHECKEQ(memio_buffer_empty(&mb), TRUE);
+    CHECKEQ(memio_buffer_full(&mb), FALSE);
+    CHECKEQ(memio_buffer_unused_contiguous(&mb), TEST_BUFLEN-1);
+    CHECKEQ(memio_buffer_unused(&mb), TEST_BUFLEN-1);
+    CHECKEQ(memio_buffer_used_contiguous(&mb), 0);
+    CHECKEQ(memio_buffer_used(&mb), 0);
+
+    CHECKEQ(memio_buffer_put(&mb, "howdy", 5), 5);
+
+    CHECKEQ(memio_buffer_empty(&mb), FALSE);
+    CHECKEQ(memio_buffer_full(&mb), FALSE);
+    CHECKEQ(memio_buffer_unused_contiguous(&mb), TEST_BUFLEN-1-5);
+    CHECKEQ(memio_buffer_unused(&mb), TEST_BUFLEN-1-5);
+    CHECKEQ(memio_buffer_used_contiguous(&mb), 5);
+    CHECKEQ(memio_buffer_used(&mb), 5);
+
+    CHECKEQ(memio_buffer_put(&mb, "!", 1), 1);
+
+    CHECKEQ(memio_buffer_empty(&mb), FALSE);
+    CHECKEQ(memio_buffer_full(&mb), TRUE);
+    CHECKEQ(memio_buffer_unused_contiguous(&mb), 0);
+    CHECKEQ(memio_buffer_unused(&mb), 0);
+    CHECKEQ(memio_buffer_used_contiguous(&mb), 6);
+    CHECKEQ(memio_buffer_used(&mb), 6);
+
+    CHECKEQ(memio_buffer_get(&mb, buf, 6), 6);
+    CHECKEQ(memcmp(buf, "howdy!", 6), 0);
+
+    CHECKEQ(memio_buffer_empty(&mb), TRUE);
+    CHECKEQ(memio_buffer_full(&mb), FALSE);
+    CHECKEQ(memio_buffer_unused(&mb), TEST_BUFLEN-1);
+    CHECKEQ(memio_buffer_unused_contiguous(&mb), 1);
+    CHECKEQ(memio_buffer_used_contiguous(&mb), 0);
+    CHECKEQ(memio_buffer_used(&mb), 0);
+
+    CHECKEQ(memio_buffer_put(&mb, "01234", 5), 5);
+
+    CHECKEQ(memio_buffer_empty(&mb), FALSE);
+    CHECKEQ(memio_buffer_full(&mb), FALSE);
+    CHECKEQ(memio_buffer_used(&mb), 5);
+    CHECKEQ(memio_buffer_used_contiguous(&mb), 1);
+    CHECKEQ(memio_buffer_unused_contiguous(&mb), TEST_BUFLEN-1-5);
+    CHECKEQ(memio_buffer_unused(&mb), TEST_BUFLEN-1-5);
+
+    CHECKEQ(memio_buffer_put(&mb, "5", 1), 1);
+
+    CHECKEQ(memio_buffer_empty(&mb), FALSE);
+    CHECKEQ(memio_buffer_full(&mb), TRUE);
+    CHECKEQ(memio_buffer_unused_contiguous(&mb), 0);
+    CHECKEQ(memio_buffer_unused(&mb), 0);
+    CHECKEQ(memio_buffer_used_contiguous(&mb), 1);
+    CHECKEQ(memio_buffer_used(&mb), 6);
+
+    /* TODO: add more cases */
+
+    printf("Test passed\n");
+    exit(0);
+}
+
+#endif