diff options
Diffstat (limited to 'usbmux.c')
| -rw-r--r-- | usbmux.c | 1259 |
1 files changed, 0 insertions, 1259 deletions
diff --git a/usbmux.c b/usbmux.c deleted file mode 100644 index e86e3bc..0000000 --- a/usbmux.c +++ /dev/null @@ -1,1259 +0,0 @@ -/* - * 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; -} |