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authorGravatar Martin Szulecki2009-05-04 18:18:40 +0200
committerGravatar Nikias Bassen2009-05-04 18:18:40 +0200
commit7364e09f6849076c710ac9ce52a5d5fd2445e19c (patch)
treeb1435d14501f704900142c0a5f7b11ea5f3217fa /src/usbmux.c
parentcae80628faeeb19a88a28d7fb058e74f8b2743ed (diff)
downloadusbmuxd-7364e09f6849076c710ac9ce52a5d5fd2445e19c.tar.gz
usbmuxd-7364e09f6849076c710ac9ce52a5d5fd2445e19c.tar.bz2
Use autotools build system and add license
Signed-off-by: Nikias Bassen <nikias@gmx.li>
Diffstat (limited to 'src/usbmux.c')
-rw-r--r--src/usbmux.c1259
1 files changed, 1259 insertions, 0 deletions
diff --git a/src/usbmux.c b/src/usbmux.c
new file mode 100644
index 0000000..e86e3bc
--- /dev/null
+++ b/src/usbmux.c
@@ -0,0 +1,1259 @@
+/*
+ * Copyright (c) 2008 Jing Su. All Rights Reserved.
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+#include <stdint.h>
+#include <stdarg.h>
+#include <stdlib.h>
+#include <string.h>
+#include <usb.h>
+#include <stdio.h>
+#include <arpa/inet.h>
+#include <errno.h>
+#include <pthread.h>
+#include "usbmux.h"
+
+#define BULKIN 0x85
+#define BULKOUT 0x04
+#define HEADERLEN 28
+
+static const uint8_t TCP_FIN = 1;
+static const uint8_t TCP_SYN = 1 << 1;
+static const uint8_t TCP_RST = 1 << 2;
+static const uint8_t TCP_PSH = 1 << 3;
+static const uint8_t TCP_ACK = 1 << 4;
+static const uint8_t TCP_URG = 1 << 5;
+
+// I have trouble figuring out how to properly manage the windowing to
+// the device. It keeps sending back 512 and seems to drop off a cliff
+// when the device gets overwhelmed. In addition, the device likes to
+// panic and send out RESETS before the window hits zero. Also, waiting
+// for responses seems to not be a winning strategy.
+//
+// Since I'm not sure how in the hell to interpret the window sizes that
+// the device is sending back to us, I've figured out some magic number
+// constants which seem to work okay.
+static const uint32_t WINDOW_MAX = 5 * 1024;
+static const uint32_t WINDOW_INCREMENT = 512;
+
+typedef struct {
+ char *buffer;
+ int leftover;
+ int capacity;
+} receivebuf_t;
+
+struct usbmux_device_int {
+ struct usb_dev_handle *usbdev;
+ struct usb_device *__device;
+ receivebuf_t usbReceive;
+};
+
+typedef struct {
+ uint32_t type, length, major, minor, allnull;
+} usbmux_version_header;
+
+typedef struct {
+ uint32_t type, length;
+ uint16_t sport, dport;
+ uint32_t scnt, ocnt;
+ uint8_t offset, tcp_flags;
+ uint16_t window, nullnull, length16;
+} usbmux_tcp_header;
+
+struct usbmux_client_int {
+ usbmux_tcp_header *header;
+ usbmux_device_t device;
+
+ char *recv_buffer;
+ int r_len;
+ pthread_cond_t wait;
+
+ // this contains a conditional variable which usb-writers can wait
+ // on while waiting for window updates from the device.
+ pthread_cond_t wr_wait;
+ // I'm going to do something really cheesy here. We are going to
+ // just record the most recent scnt that we are expecting to hear
+ // back on. We will actually halt progress by limiting the number
+ // of outstanding un-acked bulk sends that we have beamed out.
+ uint32_t wr_pending_scnt;
+ long wr_window;
+
+ pthread_mutex_t mutex;
+
+ // this variable is not protected by the mutex. This will always
+ // be E_SUCCESS, unless an error of some kind breaks this stream.
+ // this will then be set to the error that caused the broken stream.
+ // no further operations other than free_client will be allowed.
+ int error;
+
+ int cleanup;
+};
+
+
+static pthread_mutex_t usbmuxmutex = PTHREAD_MUTEX_INITIALIZER;
+static usbmux_client_t *connlist = NULL;
+static int clients = 0;
+
+
+/**
+ */
+int toto_debug = 0;
+
+void usbmux_set_debug(int e)
+{
+ toto_debug = e;
+}
+
+void log_debug_msg(const char *format, ...)
+{
+#ifndef STRIP_DEBUG_CODE
+ va_list args;
+ /* run the real fprintf */
+ va_start(args, format);
+
+ if (toto_debug)
+ vfprintf(stderr, format, args);
+
+ va_end(args);
+#endif
+}
+
+#ifdef DEBUG
+/**
+ * for debugging purposes.
+ */
+static void print_buffer(const char *data, const int length)
+{
+ if (toto_debug <= 0) {
+ return;
+ }
+ int i;
+ int j;
+ unsigned char c;
+
+ for (i = 0; i < length; i += 16) {
+ printf("%04x: ", i);
+ for (j = 0; j < 16; j++) {
+ if (i + j >= length) {
+ printf(" ");
+ continue;
+ }
+ printf("%02hhx ", *(data + i + j));
+ }
+ printf(" | ");
+ for (j = 0; j < 16; j++) {
+ if (i + j >= length)
+ break;
+ c = *(data + i + j);
+ if ((c < 32) || (c > 127)) {
+ printf(".");
+ continue;
+ }
+ printf("%c", c);
+ }
+ printf("\n");
+ }
+ printf("\n");
+}
+#endif
+
+void hton_header(usbmux_tcp_header * hdr)
+{
+ if (hdr) {
+ hdr->length = htonl(hdr->length);
+ hdr->scnt = htonl(hdr->scnt);
+ hdr->ocnt = htonl(hdr->ocnt);
+ hdr->length16 = htons(hdr->length16);
+ }
+}
+
+void ntoh_header(usbmux_tcp_header * hdr)
+{
+ if (hdr) {
+ hdr->length = ntohl(hdr->length);
+ hdr->scnt = ntohl(hdr->scnt);
+ hdr->ocnt = ntohl(hdr->ocnt);
+ hdr->length16 = ntohs(hdr->length16);
+ }
+}
+
+/** Creates a USBMux header containing version information
+ *
+ * @return A USBMux header
+ */
+usbmux_version_header *version_header()
+{
+ usbmux_version_header *version =
+ (usbmux_version_header *) malloc(sizeof(usbmux_version_header));
+ version->type = 0;
+ version->length = htonl(20);
+ version->major = htonl(1);
+ version->minor = 0;
+ version->allnull = 0;
+ return version;
+}
+
+/**
+ * This function sets the configuration of the given device to 3
+ * and claims the interface 1. If usb_set_configuration fails, it detaches
+ * the kernel driver that blocks the device, and retries configuration.
+ *
+ * @param device which device to configure
+ */
+static int usbmux_config_usb_device(usbmux_device_t device)
+{
+ int ret;
+ int bytes;
+ char buf[512];
+
+#if 0
+ log_debug_msg("checking configuration...\n");
+ if (device->__device->config->bConfigurationValue != 3) {
+ log_debug_msg
+ ("WARNING: usb device configuration is not 3 as expected!\n");
+ }
+
+ log_debug_msg("setting configuration...\n");
+ ret = usb_set_configuration(device->device, 3);
+ if (ret != 0) {
+ log_debug_msg("Hm, usb_set_configuration returned %d: %s\n", ret,
+ strerror(-ret));
+#if LIBUSB_HAS_GET_DRIVER_NP
+ log_debug_msg("trying to fix:\n");
+ log_debug_msg("-> detaching kernel driver... ");
+ ret =
+ usb_detach_kernel_driver_np(device->device,
+ device->__device->config->
+ interface->altsetting->
+ bInterfaceNumber);
+ if (ret != 0) {
+ log_debug_msg("usb_detach_kernel_driver_np returned %d: %s\n",
+ ret, strerror(-ret));
+ } else {
+ log_debug_msg("done.\n");
+ log_debug_msg("setting configuration again... ");
+ ret = usb_set_configuration(device->device, 3);
+ if (ret != 0) {
+ log_debug_msg
+ ("Error: usb_set_configuration returned %d: %s\n", ret,
+ strerror(-ret));
+ log_debug_msg("--> trying to continue anyway...\n");
+ } else {
+ log_debug_msg("done.\n");
+ }
+ }
+#else
+ log_debug_msg("--> trying to continue anyway...\n");
+#endif
+ } else {
+ log_debug_msg("done.\n");
+ }
+#endif
+
+ log_debug_msg("claiming interface... ");
+ ret = usb_claim_interface(device->usbdev, 1);
+ if (ret != 0) {
+ log_debug_msg("Error: usb_claim_interface returned %d: %s\n", ret,
+ strerror(-ret));
+ return -ENODEV;
+ } else {
+ log_debug_msg("done.\n");
+ }
+
+ do {
+ bytes = usb_bulk_read(device->usbdev, BULKIN, buf, 512, 800);
+ } while (bytes > 0);
+
+ return 0;
+}
+
+/**
+ * Given a USB bus and device number, returns a device handle to the device on
+ * that bus. To aid compatibility with future devices, this function does not
+ * check the vendor and device IDs! To do that, you should use
+ * usbmux_get_device() or a system-specific API (e.g. HAL).
+ *
+ * @param bus_n The USB bus number.
+ * @param dev_n The USB device number.
+ * @param device A pointer to a usbmux_device_t, which must be set to NULL upon
+ * calling usbmux_get_specific_device, which will be filled with a device
+ * descriptor on return.
+ * @return 0 if ok, otherwise a negative errno value.
+ */
+int usbmux_get_specific_device(int bus_n, int dev_n,
+ usbmux_device_t * device)
+{
+ struct usb_bus *bus;
+ struct usb_device *dev;
+ usbmux_version_header *version;
+ int bytes = 0;
+
+ //check we can actually write in device
+ if (!device || (device && *device))
+ return -EINVAL;
+
+ usbmux_device_t newdevice =
+ (usbmux_device_t) malloc(sizeof(struct usbmux_device_int));
+
+ // Initialize the struct
+ newdevice->usbdev = NULL;
+ newdevice->__device = NULL;
+
+ // don't forget these:
+ newdevice->usbReceive.buffer = NULL;
+ newdevice->usbReceive.leftover = 0;
+ newdevice->usbReceive.capacity = 0;
+
+ // Initialize libusb
+ usb_init();
+ usb_find_busses();
+ usb_find_devices();
+
+ // Set the device configuration
+ for (bus = usb_get_busses(); bus; bus = bus->next)
+ //if (bus->location == bus_n)
+ for (dev = bus->devices; dev != NULL; dev = dev->next)
+ if (dev->devnum == dev_n) {
+ newdevice->__device = dev;
+ newdevice->usbdev = usb_open(newdevice->__device);
+ if (usbmux_config_usb_device(newdevice) == 0) {
+ goto found;
+ }
+ }
+
+ usbmux_free_device(newdevice);
+
+ log_debug_msg("usbmux_get_specific_device: device not found\n");
+ return -ENODEV;
+
+ found:
+ // Send the version command to the device
+ version = version_header();
+ bytes =
+ usb_bulk_write(newdevice->usbdev, BULKOUT, (char *) version,
+ sizeof(*version), 800);
+ if (bytes < 20) {
+ log_debug_msg("%s: libusb did NOT send enough!\n", __func__);
+ if (bytes < 0) {
+ log_debug_msg("%s: libusb gave me the error %d: %s (%s)\n",
+ __func__, bytes, usb_strerror(),
+ strerror(-bytes));
+ }
+ }
+ // Read the device's response
+ bytes =
+ usb_bulk_read(newdevice->usbdev, BULKIN, (char *) version,
+ sizeof(*version), 800);
+
+ // Check for bad response
+ if (bytes < 20) {
+ free(version);
+ usbmux_free_device(newdevice);
+ log_debug_msg("%s: Invalid version message -- header too short.\n",
+ __func__);
+ if (bytes < 0) {
+ log_debug_msg("%s: libusb error message %d: %s (%s)\n",
+ __func__, bytes, usb_strerror(),
+ strerror(-bytes));
+ return bytes;
+ }
+ return -EBADMSG;
+ }
+ // Check for correct version
+ if (ntohl(version->major) == 1 && ntohl(version->minor) == 0) {
+ // We're all ready to roll.
+ log_debug_msg("%s: success\n", __func__);
+ free(version);
+ *device = newdevice;
+ return 0;
+ } else {
+ // Bad header
+ usbmux_free_device(newdevice);
+ free(version);
+ log_debug_msg("%s: Received a bad header/invalid version number.",
+ __func__);
+ return -EBADMSG;
+ }
+
+ // If it got to this point it's gotta be bad
+ log_debug_msg("%s: Unknown error.\n", __func__);
+ usbmux_free_device(newdevice);
+ free(version);
+ return -EBADMSG; // if it got to this point it's gotta be bad
+}
+
+/** Cleans up an usbmux_device_t structure, then frees the structure itself.
+ * This is a library-level function; deals directly with the device to tear
+ * down relations, but otherwise is mostly internal.
+ *
+ * @param device A pointer to an usbmux_device_t structure.
+ */
+int usbmux_free_device(usbmux_device_t device)
+{
+ char buf[512];
+ int bytes;
+
+ if (!device)
+ return -EINVAL;
+ int ret = 0;
+
+ if (device->usbdev) {
+ do {
+ bytes = usb_bulk_read(device->usbdev, BULKIN, buf, 512, 800);
+ } while (bytes > 0);
+ }
+
+ if (bytes < 0) {
+ ret = bytes;
+ }
+
+ if (device->usbReceive.buffer) {
+ free(device->usbReceive.buffer);
+ }
+ if (device->usbdev) {
+ usb_release_interface(device->usbdev, 1);
+ usb_close(device->usbdev);
+ ret = 0;
+ }
+ free(device);
+
+ return ret;
+}
+
+
+
+/** Sends data to the device
+ * This is a low-level (i.e. directly to device) function.
+ *
+ * @param device The device to send data to
+ * @param data The data to send
+ * @param datalen The length of the data
+ * @return The number of bytes sent, or -ERRNO on error
+ */
+int send_to_device(usbmux_device_t device, char *data, int datalen)
+{
+ if (!device)
+ return -EINVAL;
+
+ int timeout = 1000;
+ int retrycount = 0;
+ int bytes = 0;
+
+#ifdef DEBUG
+#ifdef DEBUG_MORE
+ printf("===============================\n%s: trying to send\n",
+ __func__);
+ print_buffer(data, datalen);
+ printf("===============================\n");
+#endif
+#endif
+ do {
+ if (retrycount > 3) {
+ log_debug_msg
+ ("EPIC FAIL! aborting on retry count overload.\n");
+ return -ECOMM;
+ }
+
+ bytes =
+ usb_bulk_write(device->usbdev, BULKOUT, data, datalen,
+ timeout);
+ if (bytes == -ETIMEDOUT) {
+ // timed out waiting for write.
+ log_debug_msg("usb_bulk_write timeout error.\n");
+ return bytes;
+ } else if (bytes < 0) {
+ log_debug_msg
+ ("usb_bulk_write failed with error. err:%d (%s)(%s)\n",
+ bytes, usb_strerror(), strerror(-bytes));
+ return bytes;
+ } else if (bytes == 0) {
+ log_debug_msg("usb_bulk_write sent nothing. retrying.\n");
+ timeout = timeout * 4;
+ retrycount++;
+ continue;
+ } else if (bytes < datalen) {
+ log_debug_msg
+ ("usb_bulk_write failed to send full dataload. %d of %d\n",
+ bytes, datalen);
+ timeout = timeout * 4;
+ retrycount++;
+ data += bytes;
+ datalen -= bytes;
+ continue;
+ }
+ } while (0); // fall out
+
+#ifdef DEBUG
+ if (bytes > 0) {
+ if (toto_debug > 0) {
+ printf(">>>>>>>>>>>>>>>>>>>>>>>>>>>>>>\n");
+ printf("%s: sent to device\n", __func__);
+ print_buffer(data, bytes);
+ printf(">>>>>>>>>>>>>>>>>>>>>>>>>>>>>>\n");
+ }
+ }
+#endif
+ return bytes;
+}
+
+/** Receives data from the device
+ * This function is a low-level (i.e. direct from device) function.
+ *
+ * @param device The device to receive data from
+ * @param data Where to put data read
+ * @param datalen How much data to read in
+ * @param timeout How many milliseconds to wait for data
+ *
+ * @return How many bytes were read in, or -1 on error.
+ */
+int recv_from_device_timeout(usbmux_device_t device, char *data,
+ int datalen, int timeoutmillis)
+{
+ if (!device)
+ return -EINVAL;
+ //log_debug_msg("%s: attempting to receive %i bytes\n", __func__, datalen);
+
+ int bytes =
+ usb_bulk_read(device->usbdev, BULKIN, data, datalen,
+ timeoutmillis);
+ // There are some things which are errors, others which are no problem.
+ // It's not documented in libUSB, but it seems that the error values
+ // returned are just negated ERRNO values.
+ if (bytes < 0) {
+ if (bytes == -ETIMEDOUT) {
+ // ignore this. it just means timeout reached before we
+ // picked up any data. no problem.
+ return 0;
+ } else {
+ fprintf(stderr, "%s: libusb gave me the error %d: %s (%s)\n",
+ __func__, bytes, usb_strerror(), strerror(-bytes));
+ log_debug_msg("%s: libusb gave me the error %d: %s (%s)\n",
+ __func__, bytes, usb_strerror(),
+ strerror(-bytes));
+ }
+ return bytes;
+ }
+#ifdef DEBUG
+ if (bytes > 0) {
+ if (toto_debug > 0) {
+ printf("<<<<<<<<<<<<<<<<<<<<<<<<<<<\n");
+ printf("%s: received from device:\n", __func__);
+ print_buffer(data, bytes);
+ printf("<<<<<<<<<<<<<<<<<<<<<<<<<<<\n");
+ }
+ }
+#endif
+
+ return bytes;
+}
+
+/** Creates a USBMux packet for the given set of ports.
+ *
+ * @param s_port The source port for the connection.
+ * @param d_port The destination port for the connection.
+ *
+ * @return A USBMux packet
+ */
+usbmux_tcp_header *new_mux_packet(uint16_t s_port, uint16_t d_port)
+{
+ usbmux_tcp_header *conn =
+ (usbmux_tcp_header *) malloc(sizeof(usbmux_tcp_header));
+ conn->type = htonl(6);
+ conn->length = HEADERLEN;
+ conn->sport = htons(s_port);
+ conn->dport = htons(d_port);
+ conn->scnt = 0;
+ conn->ocnt = 0;
+ conn->offset = 0x50;
+ conn->window = htons(0x0200);
+ conn->nullnull = 0x0000;
+ conn->length16 = HEADERLEN;
+ return conn;
+}
+
+
+/** Removes a connection from the list of connections made.
+ * The list of connections is necessary for buffering.
+ *
+ * @param connection The connection to delete from the tracking list.
+ */
+static void delete_connection(usbmux_client_t connection)
+{
+ usbmux_client_t *newlist = NULL;
+
+ pthread_mutex_lock(&usbmuxmutex);
+
+ // update the global list of connections
+ if (clients > 1) {
+ newlist =
+ (usbmux_client_t *) malloc(sizeof(usbmux_client_t) *
+ (clients - 1));
+ int i = 0, j = 0;
+ for (i = 0; i < clients; i++) {
+ if (connlist[i] == connection)
+ continue;
+ else {
+ newlist[j] = connlist[i];
+ j++;
+ }
+ }
+ }
+ if (connlist) {
+ free(connlist);
+ }
+ connlist = newlist;
+ clients--;
+
+ // free up this connection
+ pthread_mutex_lock(&connection->mutex);
+ if (connection->recv_buffer) {
+ free(connection->recv_buffer);
+ connection->recv_buffer = NULL;
+ }
+ if (connection->header) {
+ free(connection->header);
+ connection->header = NULL;
+ }
+ connection->r_len = 0;
+ pthread_mutex_unlock(&connection->mutex);
+ pthread_mutex_destroy(&connection->mutex);
+ free(connection);
+
+ pthread_mutex_unlock(&usbmuxmutex);
+}
+
+/** Adds a connection to the list of connections made.
+ * The connection list is necessary for buffering.
+ *
+ * @param connection The connection to add to the global list of connections.
+ */
+
+static void add_connection(usbmux_client_t connection)
+{
+ pthread_mutex_lock(&usbmuxmutex);
+ usbmux_client_t *newlist =
+ (usbmux_client_t *) realloc(connlist,
+ sizeof(usbmux_client_t) * (clients +
+ 1));
+ newlist[clients] = connection;
+ connlist = newlist;
+ clients++;
+ pthread_mutex_unlock(&usbmuxmutex);
+}
+
+/**
+ * Get a source port number that is not used by one of our connections
+ * This is needed for us to make sure we are not sending on another
+ * connection.
+ */
+static uint16_t get_free_port()
+{
+ int i;
+ uint16_t newport = 30000;
+ int cnt = 0;
+
+ pthread_mutex_lock(&usbmuxmutex);
+ while (1) {
+ cnt = 0;
+ for (i = 0; i < clients; i++) {
+ if (ntohs(connlist[i]->header->sport) == newport) {
+ cnt++;
+ }
+ }
+ if (cnt == 0) {
+ // newport is not used in our list of connections!
+ break;
+ } else {
+ newport++;
+ if (newport < 30000) {
+ // if all ports from 30000 to 65535 are in use,
+ // the value wraps (16-bit overflow)
+ // return 0, no port is available.
+ // This should not happen, but just in case ;)
+ newport = 0;
+ break;
+ }
+ }
+ }
+ pthread_mutex_unlock(&usbmuxmutex);
+
+ return newport;
+}
+
+/** Initializes a connection to 'device' with source port s_port and destination port d_port
+ *
+ * @param device The device to initialize a connection on.
+ * @param src_port The source port
+ * @param dst_port The destination port -- 0xf27e for lockdownd.
+ * @param client A mux TCP header for the connection which is used for tracking and data transfer.
+ * @return 0 on success, a negative errno value otherwise.
+ */
+int usbmux_new_client(usbmux_device_t device, uint16_t src_port,
+ uint16_t dst_port, usbmux_client_t * client)
+{
+ if (!device || !dst_port)
+ return -EINVAL;
+
+ src_port = get_free_port();
+
+ if (!src_port) {
+ // this is a special case, if we get 0, this is not good, so
+ return -EISCONN; // TODO: error code suitable?
+ }
+ // Initialize connection stuff
+ usbmux_client_t new_connection =
+ (usbmux_client_t) malloc(sizeof(struct usbmux_client_int));
+ new_connection->header = new_mux_packet(src_port, dst_port);
+
+ // send TCP syn
+ if (new_connection && new_connection->header) {
+ int err = 0;
+ new_connection->header->tcp_flags = TCP_SYN;
+ new_connection->header->length = new_connection->header->length;
+ new_connection->header->length16 =
+ new_connection->header->length16;
+ new_connection->header->scnt = 0;
+ new_connection->header->ocnt = 0;
+ new_connection->device = device;
+ new_connection->recv_buffer = NULL;
+ new_connection->r_len = 0;
+ pthread_cond_init(&new_connection->wait, NULL);
+ pthread_mutex_init(&new_connection->mutex, NULL);
+ pthread_cond_init(&new_connection->wr_wait, NULL);
+ new_connection->wr_pending_scnt = 0;
+ new_connection->wr_window = 0;
+ add_connection(new_connection);
+ new_connection->error = 0;
+ new_connection->cleanup = 0;
+ hton_header(new_connection->header);
+ log_debug_msg("%s: send_to_device (%d --> %d)\n", __func__,
+ ntohs(new_connection->header->sport),
+ ntohs(new_connection->header->dport));
+ err =
+ send_to_device(device, (char *) new_connection->header,
+ sizeof(usbmux_tcp_header));
+ if (err >= 0) {
+ *client = new_connection;
+ return 0;
+ } else {
+ delete_connection(new_connection);
+ return err;
+ }
+ }
+ // if we get to this point it's probably bad
+ return -ENOMEM;
+}
+
+/** Cleans up the given USBMux connection.
+ * @note Once a connection is closed it may not be used again.
+ *
+ * @param connection The connection to close.
+ *
+ * @return 0 on success or a negative errno value on error.
+ */
+int usbmux_free_client(usbmux_client_t client)
+{
+ if (!client || !client->device)
+ return -EINVAL;
+
+ int err = 0;
+ int result = 0;
+ pthread_mutex_lock(&client->mutex);
+ client->header->tcp_flags = TCP_FIN;
+ client->header->length = 0x1C;
+ client->header->window = 0;
+ client->header->length16 = 0x1C;
+ hton_header(client->header);
+
+ err =
+ send_to_device(client->device, (char *) client->header,
+ sizeof(usbmux_tcp_header));
+ if (err < 0) {
+ log_debug_msg("%s: error sending TCP_FIN\n", __func__);
+ result = err;
+ }
+
+ client->cleanup = 1;
+
+ // make sure we don't have any last-minute laggards waiting on this.
+ // I put it after the mutex unlock because we have cases where the
+ // conditional wait is dependent on re-grabbing that mutex.
+ pthread_cond_broadcast(&client->wait);
+ pthread_cond_destroy(&client->wait);
+ pthread_cond_broadcast(&client->wr_wait);
+ pthread_cond_destroy(&client->wr_wait);
+
+ pthread_mutex_unlock(&client->mutex);
+
+ return result;
+}
+
+/** Sends the given data over the selected connection.
+ *
+ * @param client The client we're sending data on.
+ * @param data A pointer to the data to send.
+ * @param datalen How much data we're sending.
+ * @param sent_bytes The number of bytes sent, minus the header (28)
+ *
+ * @return 0 on success or a negative errno value on error.
+ */
+int usbmux_send(usbmux_client_t client, const char *data, uint32_t datalen,
+ uint32_t * sent_bytes)
+{
+ if (!client->device || !client || !sent_bytes)
+ return -EINVAL;
+
+ if (client->error < 0) {
+ return client->error;
+ }
+
+ *sent_bytes = 0;
+ pthread_mutex_lock(&client->mutex);
+
+ int sendresult = 0;
+ uint32_t blocksize = 0;
+ if (client->wr_window <= 0) {
+ struct timespec ts;
+ clock_gettime(CLOCK_REALTIME, &ts);
+ //ts.tv_sec += 1;
+ ts.tv_nsec += 750 * 1000;
+ if (pthread_cond_timedwait(&client->wait, &client->mutex, &ts) ==
+ ETIMEDOUT) {
+ // timed out. optimistically grow the window and try to make progress
+ client->wr_window += WINDOW_INCREMENT;
+ }
+ }
+
+ blocksize = sizeof(usbmux_tcp_header) + datalen;
+
+ // client->scnt and client->ocnt should already be in host notation...
+ // we don't need to change them juuuust yet.
+ char *buffer = (char *) malloc(blocksize + 2); // allow 2 bytes of safety padding
+ // Set the length
+ client->header->length = blocksize;
+ client->header->length16 = blocksize;
+
+ // Put header into big-endian notation
+ hton_header(client->header);
+ // Concatenation of stuff in the buffer.
+ memcpy(buffer, client->header, sizeof(usbmux_tcp_header));
+ memcpy(buffer + sizeof(usbmux_tcp_header), data, datalen);
+
+ log_debug_msg("%s: send_to_device(%d --> %d)\n", __func__,
+ ntohs(client->header->sport),
+ ntohs(client->header->dport));
+ sendresult = send_to_device(client->device, buffer, blocksize);
+ // Now that we've sent it off, we can clean up after our sloppy selves.
+ if (buffer)
+ free(buffer);
+
+ // revert header fields that have been swapped before trying to send
+ ntoh_header(client->header);
+
+ // update counts ONLY if the send succeeded.
+ if ((uint32_t) sendresult == blocksize) {
+ // Re-calculate scnt
+ client->header->scnt += datalen;
+ client->wr_window -= blocksize;
+ }
+
+ pthread_mutex_unlock(&client->mutex);
+
+ if (sendresult == -ETIMEDOUT || sendresult == 0) {
+ // no problem for now...
+ *sent_bytes = 0;
+ return -ETIMEDOUT;
+ } else if (sendresult < 0) {
+ return sendresult;
+ } else if ((uint32_t) sendresult == blocksize) {
+ // actual number of data bytes sent.
+ *sent_bytes = sendresult - HEADERLEN;
+ return 0;
+ } else {
+ fprintf(stderr,
+ "usbsend managed to dump a packet that is not full size. %d of %d\n",
+ sendresult, blocksize);
+ return -EBADMSG;
+ }
+}
+
+/** append the packet's DATA to the receive buffer for the client.
+ *
+ * this has a few other corner-case functions:
+ * 1. this will properly handle the handshake syn+ack.
+ * 2. for all receives, this will appropriately update the ocnt.
+ *
+ * @return number of bytes consumed (header + data)
+ */
+uint32_t append_receive_buffer(usbmux_client_t client, char *packet)
+{
+ if (client == NULL || packet == NULL)
+ return 0;
+
+ usbmux_tcp_header *header = (usbmux_tcp_header *) packet;
+ char *data = &packet[HEADERLEN];
+ uint32_t packetlen = ntohl(header->length);
+ uint32_t datalen = packetlen - HEADERLEN;
+
+ int dobroadcast = 0;
+
+ pthread_mutex_lock(&client->mutex);
+
+ // we need to handle a few corner case tasks and book-keeping which
+ // falls on our responsibility because we are the ones reading in
+ // feedback.
+ if (client->header->scnt == 0 && client->header->ocnt == 0) {
+ log_debug_msg("client is still waiting for handshake.\n");
+ if (header->tcp_flags == (TCP_SYN | TCP_ACK)) {
+ log_debug_msg("yes, got syn+ack ; replying with ack.\n");
+ client->header->tcp_flags = TCP_ACK;
+ client->header->length = sizeof(usbmux_tcp_header);
+ client->header->length16 = sizeof(usbmux_tcp_header);
+ client->header->scnt += 1;
+ client->header->ocnt = header->ocnt;
+ hton_header(client->header);
+ // push it to USB
+ // TODO: need to check for error in the send here.... :(
+ log_debug_msg("%s: send_to_device (%d --> %d)\n", __func__,
+ ntohs(client->header->sport),
+ ntohs(client->header->dport));
+ if (send_to_device
+ (client->device, (char *) client->header,
+ sizeof(usbmux_tcp_header)) <= 0) {
+ log_debug_msg("%s: error when pushing to usb...\n",
+ __func__);
+ }
+ // need to revert some of the fields back to host notation.
+ ntoh_header(client->header);
+ } else {
+ client->error = -ECONNABORTED;
+ // woah... this connection failed us.
+ // TODO: somehow signal that this stream is a no-go.
+ log_debug_msg("WOAH! client failed to get proper syn+ack.\n");
+ }
+ }
+ // update TCP counters and windows.
+ //
+ // save the window that we're getting from the USB device.
+ // apparently the window is bigger than just the 512 that's typically
+ // advertised. iTunes apparently shifts this value by 8 to get a much
+ // larger number.
+ if (header->tcp_flags & TCP_RST) {
+ client->error = -ECONNRESET;
+
+ if (datalen > 0) {
+ char e_msg[128];
+ e_msg[0] = 0;
+ if (datalen > 1) {
+ memcpy(e_msg, data + 1, datalen - 1);
+ e_msg[datalen - 1] = 0;
+ }
+ // fetch the message
+ switch (data[0]) {
+ case 0:
+ // this is not an error, it's just a status message.
+ log_debug_msg("received status message: %s\n", e_msg);
+ datalen = 0;
+ break;
+ case 1:
+ log_debug_msg("received error message: %s\n", e_msg);
+ datalen = 0;
+ break;
+ default:
+ log_debug_msg
+ ("received unknown message (type 0x%02x): %s\n",
+ data[0], e_msg);
+ //datalen = 0; // <-- we let this commented out for testing
+ break;
+ }
+ } else {
+ log_debug_msg
+ ("peer sent connection reset. setting error: %d\n",
+ client->error);
+ }
+ }
+ // the packet's ocnt tells us how much of our data the device has received.
+ if (header->tcp_flags & TCP_ACK) {
+ // this is a hacky magic number condition. it seems that once
+ // the window reported by the device starts to drop below this
+ // number, we quickly fall into connection reset problems.
+ // Once we see the reported window size start falling off,
+ // ut off and wait for solid acks to come back.
+ if (ntohs(header->window) < 256)
+ client->wr_window = 0;
+
+ // check what just got acked.
+ if (ntohl(header->ocnt) < client->header->scnt) {
+ // we got some kind of ack, but it hasn't caught up
+ // with the pending that have been sent.
+ pthread_cond_broadcast(&client->wr_wait);
+ } else if (ntohl(header->ocnt) >
+ /*client->wr_pending_scnt */ client->header->scnt) {
+ fprintf(stderr,
+ "WTF?! acks overtook pending outstanding. %u,%u\n",
+ ntohl(header->ocnt), client->wr_pending_scnt);
+ } else {
+ // reset the window
+ client->wr_window = WINDOW_MAX;
+ pthread_cond_broadcast(&client->wr_wait);
+ }
+ }
+ // the packet's scnt will be our new ocnt.
+ client->header->ocnt = ntohl(header->scnt);
+
+ // ensure there is enough space, either by first malloc or realloc
+ if (datalen > 0) {
+ log_debug_msg("%s: putting %d bytes into client's recv_buffer\n",
+ __func__, datalen);
+ if (client->r_len == 0)
+ dobroadcast = 1;
+
+ if (client->recv_buffer == NULL) {
+ client->recv_buffer = malloc(datalen);
+ client->r_len = 0;
+ } else {
+ client->recv_buffer =
+ realloc(client->recv_buffer, client->r_len + datalen);
+ }
+
+ memcpy(&client->recv_buffer[client->r_len], data, datalen);
+ client->r_len += datalen;
+ }
+
+ pthread_mutex_unlock(&client->mutex);
+
+ // I put this outside the mutex unlock just so that when the threads
+ // wake, we don't have to do another round of unlock+try to grab.
+ if (dobroadcast)
+ pthread_cond_broadcast(&client->wait);
+
+ return packetlen;
+}
+
+/**
+ * @note THERE IS NO MUTEX LOCK IN THIS FUNCTION!
+ * because we're only called from one location, pullbulk, where the lock
+ * is already held.
+ */
+usbmux_client_t find_client(usbmux_tcp_header * recv_header)
+{
+ // remember, as we're looking for the client, the receive header is
+ // coming from the USB into our client. This means that when we check
+ // the src/dst ports, we need to reverse them.
+ usbmux_client_t retval = NULL;
+
+ // just for debugging check, I'm going to convert the numbers to host-endian.
+ uint16_t hsport = ntohs(recv_header->sport);
+ uint16_t hdport = ntohs(recv_header->dport);
+
+ pthread_mutex_lock(&usbmuxmutex);
+ int i;
+ for (i = 0; i < clients; i++) {
+ uint16_t csport = ntohs(connlist[i]->header->sport);
+ uint16_t cdport = ntohs(connlist[i]->header->dport);
+
+ if (hsport == cdport && hdport == csport) {
+ retval = connlist[i];
+ break;
+ }
+ }
+ pthread_mutex_unlock(&usbmuxmutex);
+
+ return retval;
+}
+
+/** pull in a big USB bulk packet and distribute it to queues appropriately.
+ */
+int usbmux_pullbulk(usbmux_device_t device)
+{
+ if (!device)
+ return -EINVAL;
+
+ int res = 0;
+ static const int DEFAULT_CAPACITY = 128 * 1024;
+ if (device->usbReceive.buffer == NULL) {
+ device->usbReceive.capacity = DEFAULT_CAPACITY;
+ device->usbReceive.buffer = malloc(device->usbReceive.capacity);
+ device->usbReceive.leftover = 0;
+ }
+ // start the cursor off just ahead of the leftover.
+ char *cursor = &device->usbReceive.buffer[device->usbReceive.leftover];
+ // pull in content, note that the amount we can pull is capacity minus leftover
+ int readlen =
+ recv_from_device_timeout(device, cursor,
+ device->usbReceive.capacity -
+ device->usbReceive.leftover, 3000);
+ if (readlen < 0) {
+ res = readlen;
+ //fprintf(stderr, "recv_from_device_timeout gave us an error.\n");
+ readlen = 0;
+ }
+ if (readlen > 0) {
+ //fprintf(stdout, "recv_from_device_timeout pulled an extra %d bytes\n", readlen);
+ }
+ // the amount of content we have to work with is the remainder plus
+ // what we managed to read
+ device->usbReceive.leftover += readlen;
+
+ // reset the cursor to the front of that buffer and work through
+ // trying to decode packets out of them.
+ cursor = device->usbReceive.buffer;
+ while (1) {
+ // check if there's even sufficient data to decode a header
+ if (device->usbReceive.leftover < HEADERLEN)
+ break;
+ usbmux_tcp_header *header = (usbmux_tcp_header *) cursor;
+
+ log_debug_msg("%s: recv_from_device_timeout (%d --> %d)\n",
+ __func__, ntohs(header->sport),
+ ntohs(header->dport));
+
+ // now that we have a header, check if there is sufficient data
+ // to construct a full packet, including its data
+ uint32_t packetlen = ntohl(header->length);
+ if ((uint32_t) device->usbReceive.leftover < packetlen) {
+ fprintf(stderr,
+ "%s: not enough data to construct a full packet\n",
+ __func__);
+ break;
+ }
+ // ok... find the client this packet will get stuffed to.
+ usbmux_client_t client = find_client(header);
+ if (client == NULL) {
+ log_debug_msg
+ ("WARNING: client for packet cannot be found. dropping packet.\n");
+ } else {
+ // stuff the data
+ log_debug_msg
+ ("%s: found client, calling append_receive_buffer\n",
+ __func__);
+ append_receive_buffer(client, cursor);
+
+ // perhaps this is too general, == -ECONNRESET
+ // might be a better check here
+ if (client->error < 0) {
+ pthread_mutex_lock(&client->mutex);
+ if (client->cleanup) {
+ pthread_mutex_unlock(&client->mutex);
+ log_debug_msg("freeing up connection (%d->%d)\n",
+ ntohs(client->header->sport),
+ ntohs(client->header->dport));
+ delete_connection(client);
+ } else {
+ pthread_mutex_unlock(&client->mutex);
+ }
+ }
+ }
+
+ // move the cursor and account for the consumption
+ cursor += packetlen;
+ device->usbReceive.leftover -= packetlen;
+ }
+
+ // now, we need to manage any leftovers.
+ // I'm going to manage the leftovers by alloc'ing a new block and
+ // copyingthe leftovers to it. This is just to prevent problems with
+ // memory moves where there may be overlap. Besides, the leftovers
+ // should be small enough that this copy is minimal in overhead.
+ //
+ // if there are no leftovers, we just leave the datastructure as is,
+ // and re-use the block next time.
+ if (device->usbReceive.leftover > 0
+ && cursor != device->usbReceive.buffer) {
+ log_debug_msg("%s: we got a leftover, so handle it\n", __func__);
+ char *newbuff = malloc(DEFAULT_CAPACITY);
+ memcpy(newbuff, cursor, device->usbReceive.leftover);
+ free(device->usbReceive.buffer);
+ device->usbReceive.buffer = newbuff;
+ device->usbReceive.capacity = DEFAULT_CAPACITY;
+ }
+
+ return res;
+}
+
+/**
+ * return the error code stored in usbmux_client_t structure,
+ * e.g. non-zero when an usb read error occurs.
+ *
+ * @param client the usbmux client
+ *
+ * @return 0 or a negative errno value.
+ */
+int usbmux_get_error(usbmux_client_t client)
+{
+ if (!client) {
+ return 0;
+ }
+ return client->error;
+}
+
+/** This function reads from the client's recv_buffer.
+ *
+ * @param client The client to receive data from.
+ * @param data Where to put the data we receive.
+ * @param datalen How much data to read.
+ * @param timeout How many milliseconds to wait for data
+ *
+ * @return 0 on success or a negative errno value on failure.
+ */
+int usbmux_recv_timeout(usbmux_client_t client, char *data,
+ uint32_t datalen, uint32_t * recv_bytes,
+ int timeout)
+{
+
+ if (!client || !data || datalen == 0 || !recv_bytes)
+ return -EINVAL;
+
+ if (client->error < 0)
+ return client->error;
+
+ pthread_mutex_lock(&client->mutex);
+
+ if (timeout > 0 && (client->recv_buffer == NULL || client->r_len == 0)) {
+ struct timespec ts;
+ clock_gettime(CLOCK_REALTIME, &ts);
+ ts.tv_sec += timeout / 1000;
+ ts.tv_nsec += (timeout - ((int) (timeout / 1000)) * 1000) * 1000;
+ pthread_cond_timedwait(&client->wait, &client->mutex, &ts);
+ }
+
+ *recv_bytes = 0;
+ if (client->recv_buffer != NULL && client->r_len > 0) {
+ uint32_t foolen = datalen;
+ if ((int) foolen > client->r_len)
+ foolen = client->r_len;
+ memcpy(data, client->recv_buffer, foolen);
+ *recv_bytes = foolen;
+
+ // preserve any left-over unread amounts.
+ int remainder = client->r_len - foolen;
+ if (remainder > 0) {
+ char *newbuf = malloc(remainder);
+ memcpy(newbuf, client->recv_buffer + foolen, remainder);
+ client->r_len = remainder;
+ free(client->recv_buffer);
+ client->recv_buffer = newbuf;
+ } else {
+ free(client->recv_buffer);
+ client->recv_buffer = NULL;
+ client->r_len = 0;
+ }
+ }
+
+ pthread_mutex_unlock(&client->mutex);
+
+ return 0;
+}