Use autotools build system and add license

Signed-off-by: Nikias Bassen <nikias@gmx.li>

9 files changed, 3317 insertions, 0 deletions

diff --git a/src/Makefile.am b/src/Makefile.am
new file mode 100644
index 0000000..547870e
--- /dev/null
+++ b/src/Makefile.am
@@ -0,0 +1,31 @@
+AM_CFLAGS = $(GLOBAL_CFLAGS) $(libusb_CFLAGS)
+AM_LDFLAGS = $(libusb_LIBS) -lpthread -lrt
+
+# Libraries
+
+noinst_LTLIBRARIES = libusbmux.la libsock_stuff.la
+libsock_stuff_la_SOURCES = sock_stuff.c \
+			   sock_stuff.h
+
+libusbmux_la_SOURCES = usbmux.c \
+		       usbmux.h
+libusbmux_la_CFLAGS = $(AM_CFLAGS)
+libusbmux_la_LDFLAGS = $(AM_LDFLAGS)
+
+lib_LTLIBRARIES = libusbmuxd.la
+libusbmuxd_la_SOURCES = libusbmuxd.c \
+		        usbmuxd.h \
+		        usbmuxd-proto.h
+libusbmuxd_la_LIBADD = libsock_stuff.la
+
+include_HEADERS = usbmuxd.h \
+		  usbmuxd-proto.h
+
+# Programs
+
+sbin_PROGRAMS = usbmuxd
+
+usbmuxd_SOURCES = main.c
+usbmuxd_LDADD = libusbmux.la \
+	        libsock_stuff.la
+
diff --git a/src/libusbmuxd.c b/src/libusbmuxd.c
new file mode 100644
index 0000000..c8acbf8
--- /dev/null
+++ b/src/libusbmuxd.c
@@ -0,0 +1,202 @@
+#include <stdint.h>
+#include <stdlib.h>
+#include <errno.h>
+#include <stdio.h>
+#include <string.h>
+#include <sys/socket.h>
+#include <arpa/inet.h>
+#include <unistd.h>
+
+// usbmuxd public interface
+#include <usbmuxd.h>
+// usbmuxd protocol 
+#include <usbmuxd-proto.h>
+// socket utility functions
+#include "sock_stuff.h"
+
+static int usbmuxd_get_result(int sfd, uint32_t tag, uint32_t * result)
+{
+	struct usbmuxd_result res;
+	int recv_len;
+
+	if (!result) {
+		return -EINVAL;
+	}
+
+	if ((recv_len = recv_buf(sfd, &res, sizeof(res))) <= 0) {
+		perror("recv");
+		return -errno;
+	} else {
+		if ((recv_len == sizeof(res))
+			&& (res.header.length == (uint32_t) recv_len)
+			&& (res.header.reserved == 0)
+			&& (res.header.type == USBMUXD_RESULT)
+			) {
+			*result = res.result;
+			if (res.header.tag == tag) {
+				return 1;
+			} else {
+				return 0;
+			}
+		}
+	}
+
+	return -1;
+}
+
+int usbmuxd_scan(usbmuxd_scan_result ** available_devices)
+{
+	struct usbmuxd_scan_request s_req;
+	int sfd;
+	int scan_success = 0;
+	uint32_t res;
+	uint32_t pktlen;
+	int recv_len;
+	usbmuxd_scan_result *newlist = NULL;
+	struct usbmuxd_device_info_record dev_info_pkt;
+	int dev_cnt = 0;
+
+	sfd = connect_unix_socket(USBMUXD_SOCKET_FILE);
+	if (sfd < 0) {
+		fprintf(stderr, "%s: error opening socket!\n", __func__);
+		return sfd;
+	}
+
+	s_req.header.length = sizeof(struct usbmuxd_scan_request);
+	s_req.header.reserved = 0;
+	s_req.header.type = USBMUXD_SCAN;
+	s_req.header.tag = 2;
+
+	// send scan request packet
+	if (send_buf(sfd, &s_req, s_req.header.length) ==
+		(int) s_req.header.length) {
+		res = -1;
+		// get response
+		if (usbmuxd_get_result(sfd, s_req.header.tag, &res) && (res == 0)) {
+			scan_success = 1;
+		} else {
+			fprintf(stderr,
+					"%s: Did not get response to scan request (with result=0)...\n",
+					__func__);
+			close(sfd);
+			return res;
+		}
+	}
+
+	if (!scan_success) {
+		fprintf(stderr, "%s: Could not send scan request!\n", __func__);
+		return -1;
+	}
+
+	*available_devices = NULL;
+	// receive device list
+	while (1) {
+		if (recv_buf_timeout(sfd, &pktlen, 4, MSG_PEEK, 1000) == 4) {
+			if (pktlen != sizeof(dev_info_pkt)) {
+				// invalid packet size received!
+				fprintf(stderr,
+						"%s: Invalid packet size (%d) received when expecting a device info record.\n",
+						__func__, pktlen);
+				break;
+			}
+
+			recv_len = recv_buf(sfd, &dev_info_pkt, pktlen);
+			if (recv_len <= 0) {
+				fprintf(stderr,
+						"%s: Error when receiving device info record\n",
+						__func__);
+				break;
+			} else if ((uint32_t) recv_len < pktlen) {
+				fprintf(stderr,
+						"%s: received less data than specified in header!\n",
+						__func__);
+			} else {
+				//fprintf(stderr, "%s: got device record with id %d, UUID=%s\n", __func__, dev_info_pkt.device_info.device_id, dev_info_pkt.device_info.serial_number);
+				newlist =
+					(usbmuxd_scan_result *) realloc(*available_devices,
+													sizeof
+													(usbmuxd_scan_result) *
+													(dev_cnt + 1));
+				if (newlist) {
+					newlist[dev_cnt].handle =
+						(int) dev_info_pkt.device.device_id;
+					newlist[dev_cnt].product_id =
+						dev_info_pkt.device.product_id;
+					memset(newlist[dev_cnt].serial_number, '\0',
+						   sizeof(newlist[dev_cnt].serial_number));
+					memcpy(newlist[dev_cnt].serial_number,
+						   dev_info_pkt.device.serial_number,
+						   sizeof(dev_info_pkt.device.serial_number));
+					*available_devices = newlist;
+					dev_cnt++;
+				} else {
+					fprintf(stderr,
+							"%s: ERROR: out of memory when trying to realloc!\n",
+							__func__);
+					break;
+				}
+			}
+		} else {
+			// we _should_ have all of them now.
+			// or perhaps an error occured.
+			break;
+		}
+	}
+
+	// terminating zero record
+	newlist =
+		(usbmuxd_scan_result *) realloc(*available_devices,
+										sizeof(usbmuxd_scan_result) *
+										(dev_cnt + 1));
+	memset(newlist + dev_cnt, 0, sizeof(usbmuxd_scan_result));
+	*available_devices = newlist;
+
+	return dev_cnt;
+}
+
+int usbmuxd_connect(const int handle, const unsigned short tcp_port)
+{
+	int sfd;
+	struct usbmuxd_connect_request c_req;
+	int connected = 0;
+	uint32_t res = -1;
+
+	sfd = connect_unix_socket(USBMUXD_SOCKET_FILE);
+	if (sfd < 0) {
+		fprintf(stderr, "%s: Error: Connection to usbmuxd failed: %s\n",
+				__func__, strerror(errno));
+		return sfd;
+	}
+
+	c_req.header.length = sizeof(c_req);
+	c_req.header.reserved = 0;
+	c_req.header.type = USBMUXD_CONNECT;
+	c_req.header.tag = 3;
+	c_req.device_id = (uint32_t) handle;
+	c_req.tcp_dport = htons(tcp_port);
+	c_req.reserved = 0;
+
+	if (send_buf(sfd, &c_req, sizeof(c_req)) < 0) {
+		perror("send");
+	} else {
+		// read ACK
+		//fprintf(stderr, "%s: Reading connect result...\n", __func__);
+		if (usbmuxd_get_result(sfd, c_req.header.tag, &res)) {
+			if (res == 0) {
+				//fprintf(stderr, "%s: Connect success!\n", __func__);
+				connected = 1;
+			} else {
+				fprintf(stderr, "%s: Connect failed, Error code=%d\n",
+						__func__, res);
+			}
+		}
+	}
+
+	if (connected) {
+		return sfd;
+	}
+
+	close(sfd);
+
+	return -1;
+}
diff --git a/src/main.c b/src/main.c
new file mode 100644
index 0000000..e7292cc
--- /dev/null
+++ b/src/main.c
@@ -0,0 +1,1351 @@
+/*
+ * usbmuxd -- daemon for communication with iPhone/iPod via USB
+ * 
+ * Copyright (c) 2009 Nikias Bassen. All Rights Reserved.
+ * Based upon iTunnel source code, Copyright (c) 2008 Jing Su.
+ *  http://www.cs.toronto.edu/~jingsu/itunnel/
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program 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 General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA 
+ */
+#include <stddef.h>
+#include <stdio.h>
+#include <errno.h>
+#include <stdlib.h>
+#include <string.h>
+#include <getopt.h>
+#include <stdarg.h>
+#include <syslog.h>
+#include <fcntl.h>
+#include <sys/socket.h>
+#include <sys/un.h>
+#include <sys/stat.h>
+#include <arpa/inet.h>
+#include <unistd.h>
+#include <signal.h>
+#include <pthread.h>
+#include <stdint.h>
+#include <usb.h>
+#include <pwd.h>
+
+#include "usbmuxd-proto.h"
+#include "sock_stuff.h"
+
+#include "usbmux.h"
+
+#define DEFAULT_TIMEOUT 4000
+#define DEFAULT_CHILDREN_CAPACITY 10
+#define DEBUG_LEVEL 0
+
+#define LOCKFILE "/var/run/usbmuxd.lock"
+
+#define THREAD (unsigned int)pthread_self()
+
+static int quit_flag = 0;
+static int fsock = -1;
+static int verbose = DEBUG_LEVEL;
+static int foreground = 0;
+static int exit_on_no_devices = 0;
+
+struct device_info {
+	uint32_t device_id;
+	usbmux_device_t phone;
+	int use_count;
+	pthread_t bulk_reader;
+	pthread_mutex_t mutex;
+	/* mutex for mutual exclusion of calling the usbmux_send function
+	 * TODO: I don't know if we need really need this? */
+	pthread_mutex_t writer_mutex;
+};
+
+struct client_data {
+	volatile int dead;
+	int socket;
+	int tag;
+	pthread_t thread;
+	pthread_t handler;
+	pthread_t reader;
+	int reader_quit;
+	int reader_dead;
+	int handler_dead;
+	int connected;
+	usbmux_client_t muxclient;
+	struct device_info *dev;
+};
+
+static struct device_info **devices = NULL;
+static int device_count = 0;
+static pthread_mutex_t usbmux_mutex = PTHREAD_MUTEX_INITIALIZER;
+static pthread_mutex_t usb_mutex = PTHREAD_MUTEX_INITIALIZER;
+
+/**
+ * logs a message to syslog when running as daemon or to stdout/stderr when
+ * running in foreground.
+ * @param prio The logging priority.
+ * @param format The message to be printed.
+ */
+static void logmsg(int prio, const char *format, ...)
+{
+	va_list args;
+	va_start(args, format);
+
+	if (!foreground) {
+		// daemon. log using syslog.
+		vsyslog(prio, format, args);
+	} else {
+		// running in foreground. log to stdout/stderr.
+		char msgbuf[256];
+		FILE *lfp = stdout;
+		switch (prio) {
+		case LOG_EMERG:
+		case LOG_ALERT:
+		case LOG_CRIT:
+		case LOG_ERR:
+		case LOG_WARNING:
+			lfp = stderr;
+			break;
+		default:
+			lfp = stdout;
+		}
+		strcpy(msgbuf, "usbmuxd: ");
+		vsnprintf(msgbuf + 9, 244, format, args);
+		strcat(msgbuf, "\n");
+		fputs(msgbuf, lfp);
+	}
+
+	va_end(args);
+}
+
+#ifdef DEBUG
+/**
+ * for debugging purposes.
+ */
+static void print_buffer(FILE * fp, const char *data, const int length)
+{
+	int i;
+	int j;
+	unsigned char c;
+
+	for (i = 0; i < length; i += 16) {
+		if (verbose >= 4)
+			fprintf(fp, "%04x: ", i);
+		for (j = 0; j < 16; j++) {
+			if (i + j >= length) {
+				if (verbose >= 4)
+					fprintf(fp, "   ");
+				continue;
+			}
+			if (verbose >= 4)
+				fprintf(fp, "%02hhx ", *(data + i + j));
+		}
+		if (verbose >= 4)
+			fprintf(fp, "  | ");
+		for (j = 0; j < 16; j++) {
+			if (i + j >= length)
+				break;
+			c = *(data + i + j);
+			if ((c < 32) || (c > 127)) {
+				if (verbose >= 4)
+					fprintf(fp, ".");
+				continue;
+			}
+			if (verbose >= 4)
+				fprintf(fp, "%c", c);
+		}
+		if (verbose >= 4)
+			fprintf(fp, "\n");
+	}
+	if (verbose >= 4)
+		fprintf(fp, "\n");
+}
+#endif
+
+/**
+ * Read incoming usbmuxd packet. If the packet is larger than
+ * the size specified by len, the data will be truncated.
+ *
+ * @param fd the file descriptor to read from.
+ * @param data pointer to a buffer to store the read data to.
+ * @param len the length of the data to be read. The buffer
+ *        pointed to by data should be at least len bytes in size.
+ *
+ * @return 
+ */
+static int usbmuxd_get_request(int fd, void **data, size_t len)
+{
+	uint32_t pktlen;
+	int recv_len;
+
+	if (peek_buf(fd, &pktlen, sizeof(pktlen)) < (int) sizeof(pktlen)) {
+		return -errno;
+	}
+
+	if (len == 0) {
+		// allocate buffer space
+		*data = malloc(pktlen);
+	} else if (len < pktlen) {
+		// target buffer is to small to hold this packet! fix it!
+		if (verbose >= 2)
+			logmsg(LOG_WARNING,
+				   "%s: WARNING -- packet (%d) is larger than target buffer (%d)! Truncating.",
+				   __func__, pktlen, len);
+		pktlen = len;
+	}
+
+	recv_len = recv_buf(fd, *data, pktlen);
+	if ((recv_len > 0) && ((uint32_t) recv_len < pktlen)) {
+		if (verbose >= 2)
+			logmsg(LOG_WARNING,
+				   "%s: Uh-oh, we got less than the packet's size, %d instead of %d...",
+				   __func__, recv_len, pktlen);
+	}
+#ifdef DEBUG
+	if (*data && (recv_len > 0) && verbose >= 4) {
+		fprintf(stderr, "%s: received:\n", __func__);
+		print_buffer(stderr, *data, recv_len);
+	}
+#endif
+
+	return recv_len;
+}
+
+/**
+ * Send a usbmuxd result packet with given tag and result_code.
+ *
+ * @param fd the file descriptor to write to.
+ * @param tag the tag value that identifies where this message belongs to.
+ * @param result_code the error value (0 = Success, most likely errno values otherwise)
+ *
+ * @return the return value returned by send_buf (normally the number of bytes sent)
+ */
+static int usbmuxd_send_result(int fd, uint32_t tag, uint32_t result_code)
+{
+	struct usbmuxd_result res;
+	int ret;
+
+	res.header.length = sizeof(res);
+	res.header.reserved = 0;
+	res.header.type = USBMUXD_RESULT;
+	res.header.tag = tag;
+	res.result = result_code;
+
+	if (verbose >= 4)
+		logmsg(LOG_NOTICE, "%s: tag=%d result=%d", __func__,
+			   res.header.tag, res.result);
+
+	ret = send_buf(fd, &res, sizeof(res));
+	fsync(fd);					// let's get it sent
+	return ret;
+}
+
+/**
+ * this thread reads from the usb connection and writes the 
+ * data to the connected client.
+ *
+ * @param arg pointer to a client_data structure.
+ *
+ * @return NULL in any case
+ */
+static void *usbmuxd_client_reader_thread(void *arg)
+{
+	struct client_data *cdata;
+
+	char rbuffer[512];
+	uint32_t rbuffersize = 512;
+	uint32_t rlen;
+	int err;
+	char *cursor;
+	ssize_t len;
+	int result;
+
+	if (!arg) {
+		if (verbose >= 2)
+			logmsg(LOG_ERR, "%s: invalid client_data supplied!", __func__);
+		cdata->reader_dead = 1;
+		return NULL;
+	}
+
+	cdata = (struct client_data *) arg;
+
+	cdata->reader_dead = 0;
+
+	if (verbose >= 3)
+		logmsg(LOG_NOTICE, "%s[%d:%d]: started", __func__,
+			   cdata->dev->device_id, cdata->dev->use_count);
+
+	while (!quit_flag && !cdata->reader_quit) {
+		result = check_fd(cdata->socket, FD_WRITE, DEFAULT_TIMEOUT);
+		if (result <= 0) {
+			if (result < 0) {
+				if (verbose >= 2)
+					logmsg(LOG_ERR, "%s: select error: %s", __func__,
+						   strerror(errno));
+			}
+			continue;
+		}
+
+		rlen = 0;
+		err =
+			usbmux_recv_timeout(cdata->muxclient, rbuffer, rbuffersize,
+								&rlen, DEFAULT_TIMEOUT);
+		if (err != 0) {
+			if (verbose >= 2)
+				logmsg(LOG_ERR,
+					   "%s[%d:%d]: encountered USB read error: %d",
+					   __func__, cdata->dev->device_id,
+					   cdata->dev->use_count, err);
+			break;
+		}
+
+		cursor = rbuffer;
+		while (rlen > 0) {
+			len = send_buf(cdata->socket, cursor, rlen);
+			if (len <= 0) {
+				logmsg(LOG_ERR, "%s: Error: send returned %d", __func__,
+					   len);
+				err = 1;
+				break;
+			}
+			// calculate remainder
+			rlen -= len;
+			// advance cursor
+			cursor += len;
+		}
+		if (err != 0) {
+			logmsg(LOG_ERR, "%s: Error when writing to client...",
+				   __func__);
+			break;
+		}
+		fsync(cdata->socket);
+	}
+
+	if (verbose >= 3)
+		logmsg(LOG_NOTICE, "%s[%d:%d]: terminated", __func__,
+			   cdata->dev->device_id, cdata->dev->use_count);
+
+	cdata->reader_dead = 1;
+
+	return NULL;
+}
+
+/**
+ * This function handles the connecting procedure to a previously
+ * set up usbmux client.
+ * Sends a usbmuxd result packet denoting success or failure.
+ * A successful result is mandatory for later communication.
+ *
+ * @param cdata pointer to a previously initialized client_data structure
+ *
+ * @return
+ */
+static int usbmuxd_handleConnectResult(struct client_data *cdata)
+{
+	int result;
+	char buffer[512];
+	char err_type[64];
+	int err_code;
+	ssize_t maxlen = 512;
+	uint32_t rlen;
+	int err;
+
+	if (!cdata) {
+		if (verbose >= 2)
+			logmsg(LOG_ERR, "%s: Invalid client_data provided!", __func__);
+		return -EINVAL;
+	}
+
+	result = check_fd(cdata->socket, FD_WRITE, DEFAULT_TIMEOUT);
+	if (result <= 0) {
+		if (result < 0) {
+			if (verbose >= 2)
+				logmsg(LOG_ERR, "%s: select error: %s", __func__,
+					   strerror(errno));
+			return result;
+		}
+	} else {
+		result = 0;
+		err =
+			usbmux_recv_timeout(cdata->muxclient, buffer, maxlen, &rlen,
+								100);
+		if (err < 0) {
+			if (verbose >= 2)
+				logmsg(LOG_ERR, "%s: encountered USB read error: %d",
+					   __func__, err);
+			usbmuxd_send_result(cdata->socket, cdata->tag, -err);
+			return err;
+		} else {
+			if (rlen > 0) {
+				if ((buffer[0] == 1) && (rlen > 20)
+					&& !memcmp(buffer + 1, "handleConnectResult:", 20)) {
+					// hm... we got an error message!
+					buffer[rlen] = 0;
+					if (verbose >= 1)
+						logmsg(LOG_ERR, "%s: %s\n", __func__, buffer + 22);
+
+					if (sscanf
+						(buffer + 22, "%s - %d\n", err_type, &err_code)
+						== 2) {
+						usbmuxd_send_result(cdata->socket, cdata->tag,
+											err_code);
+						return -err_code;
+					} else {
+						usbmuxd_send_result(cdata->socket, cdata->tag,
+											ENODATA);
+						return -ENODATA;
+					}
+				} else {
+					// send success result
+					usbmuxd_send_result(cdata->socket, cdata->tag, 0);
+					// and the server greeting message
+					send_buf(cdata->socket, buffer, rlen);
+				}
+			} else {
+				// no server greeting? this seems to be ok. send success.
+				usbmuxd_send_result(cdata->socket, cdata->tag, 0);
+			}
+		}
+		//fsync(cdata->socket);
+	}
+	return result;
+}
+
+/**
+ * This thread handles the communication between the connected iPhone/iPod
+ * and the client that created the connection.
+ */
+static void *usbmuxd_client_handler_thread(void *arg)
+{
+	struct client_data *cdata;
+	int result;
+	char *cursor;
+	char buffer[65536];
+	ssize_t len;
+	ssize_t maxlen = sizeof(buffer);
+	uint32_t wlen;
+	int err;
+
+	if (!arg) {
+		if (verbose >= 2)
+			logmsg(LOG_ERR, "%s: invalid client_data provided!", __func__);
+		return NULL;
+	}
+
+	cdata = (struct client_data *) arg;
+
+	if (verbose >= 3)
+		logmsg(LOG_NOTICE, "%s[%d:%d]: started", __func__,
+			   cdata->dev->device_id, cdata->dev->use_count);
+
+	if (usbmuxd_handleConnectResult(cdata)) {
+		if (verbose >= 3)
+			logmsg(LOG_ERR, "handleConnectResult: Error");
+		goto leave;
+	} else {
+		if (verbose >= 3)
+			logmsg(LOG_NOTICE, "handleConnectResult: Success");
+	}
+
+	// starting mux reader thread
+	cdata->reader_quit = 0;
+	cdata->reader_dead = 0;
+	if (pthread_create
+		(&cdata->reader, NULL, usbmuxd_client_reader_thread, cdata) != 0) {
+		if (verbose >= 2)
+			logmsg(LOG_ERR, "%s: could not start client_reader thread",
+				   __func__);
+		cdata->reader = 0;
+	}
+
+	while (!quit_flag && !cdata->reader_dead) {
+		result = check_fd(cdata->socket, FD_READ, DEFAULT_TIMEOUT);
+		if (result <= 0) {
+			if (result < 0) {
+				if (verbose >= 3)
+					logmsg(LOG_ERR, "%s: Error: checkfd: %s", __func__,
+						   strerror(errno));
+			}
+			continue;
+		}
+		// check_fd told us there's data available, so read from client
+		// and push to USB device.
+		len = recv(cdata->socket, buffer, maxlen, 0);
+		if (len == 0) {
+			break;
+		}
+		if (len < 0) {
+			if (verbose >= 2)
+				logmsg(LOG_ERR, "%s[%d:%d]: Error: recv: %s", __func__,
+					   cdata->dev->device_id, cdata->dev->use_count,
+					   strerror(errno));
+			break;
+		}
+
+		cursor = buffer;
+
+		pthread_mutex_lock(&cdata->dev->writer_mutex);
+		do {
+			wlen = 0;
+			err = usbmux_send(cdata->muxclient, cursor, len, &wlen);
+			if (err == -ETIMEDOUT) {
+				// some kind of timeout... just be patient and retry.
+			} else if (err < 0) {
+				if (verbose >= 2)
+					logmsg(LOG_ERR, "%s[%d:%d]: USB write error: %d",
+						   __func__, cdata->dev->device_id,
+						   cdata->dev->use_count, err);
+				len = -1;
+				break;
+			}
+			// calculate remainder.
+			len -= wlen;
+			// advance cursor appropiately.
+			cursor += wlen;
+		}
+		while ((len > 0) && !quit_flag);
+		pthread_mutex_unlock(&cdata->dev->writer_mutex);
+		if (len < 0) {
+			break;
+		}
+	}
+
+  leave:
+	// cleanup
+	if (verbose >= 3)
+		logmsg(LOG_NOTICE, "%s[%d:%d]: terminating", __func__,
+			   cdata->dev->device_id, cdata->dev->use_count);
+	if (cdata->reader != 0) {
+		cdata->reader_quit = 1;
+		pthread_join(cdata->reader, NULL);
+	}
+
+	cdata->handler_dead = 1;
+
+	if (verbose >= 3)
+		logmsg(LOG_NOTICE, "%s[%d:%d]: terminated", __func__,
+			   cdata->dev->device_id, cdata->dev->use_count);
+	return NULL;
+}
+
+/**
+ * Thread performing usb_bulk_read from the connected device.
+ * One thread per device. Lives as long as the device is in use.
+ */
+static void *usbmuxd_bulk_reader_thread(void *arg)
+{
+	struct device_info *cur_dev;
+	int err;
+
+	if (!arg) {
+		if (verbose >= 2)
+			logmsg(LOG_ERR, "%s: Invalid client_data provided", __func__);
+		return NULL;
+	}
+
+	cur_dev = (struct device_info *) arg;
+
+	if (verbose >= 3)
+		logmsg(LOG_NOTICE, "%s: started", __func__);
+
+	while (!quit_flag && cur_dev) {
+
+		pthread_mutex_lock(&cur_dev->mutex);
+		if (cur_dev->use_count <= 0) {
+			pthread_mutex_unlock(&cur_dev->mutex);
+			break;
+		}
+		pthread_mutex_unlock(&cur_dev->mutex);
+
+		if ((err = usbmux_pullbulk(cur_dev->phone)) < 0) {
+			if (verbose >= 1)
+				logmsg(LOG_ERR, "%s: error %d when reading from device",
+					   __func__, err);
+			break;
+		}
+	}
+
+	if (verbose >= 3)
+		logmsg(LOG_NOTICE, "%s: terminated", __func__);
+
+	return NULL;
+}
+
+/**
+ * This thread is started when a new connection is accepted.
+ * It performs the handshake, then waits for the connect packet and
+ * on success it starts the usbmuxd_client_handler thread.
+ */
+static void *usbmuxd_client_init_thread(void *arg)
+{
+	struct client_data *cdata;
+	struct usbmuxd_scan_request *s_req = NULL;
+	struct usbmuxd_device_info_record dev_info_rec;
+	struct usbmuxd_connect_request *c_req = NULL;
+
+	struct usb_bus *bus;
+	struct usb_device *dev;
+
+	int recv_len;
+	int found = 0;
+	int res;
+	int i;
+
+	usbmux_device_t phone = NULL;
+	struct device_info *cur_dev = NULL;
+
+	if (!arg) {
+		if (verbose >= 1)
+			logmsg(LOG_ERR, "%s[%x]: invalid client_data provided!",
+				   __func__, THREAD);
+		return NULL;
+	}
+
+	cdata = (struct client_data *) arg;
+	cdata->dead = 0;
+
+	if (verbose >= 3)
+		logmsg(LOG_NOTICE, "%s[%x]: started (fd=%d)", __func__, THREAD,
+			   cdata->socket);
+
+	if ((recv_len =
+		 usbmuxd_get_request(cdata->socket, (void **) &s_req, 0)) <= 0) {
+		if (verbose >= 2)
+			logmsg(LOG_ERR, "%s[%x]: No scan packet received, error %s",
+				   __func__, THREAD, strerror(errno));
+		goto leave;
+	}
+
+	if ((recv_len == sizeof(struct usbmuxd_scan_request))
+		&& (s_req->header.length == sizeof(struct usbmuxd_scan_request))
+		&& (s_req->header.reserved == 0)
+		&& (s_req->header.type == USBMUXD_SCAN)) {
+		// send success response
+		if (verbose >= 3)
+			logmsg(LOG_NOTICE, "%s[%x]: Got scan packet!", __func__,
+				   THREAD);
+		usbmuxd_send_result(cdata->socket, s_req->header.tag, 0);
+	} else if ((recv_len == sizeof(struct usbmuxd_connect_request))
+			   && (s_req->header.type == USBMUXD_CONNECT)) {
+		c_req = (struct usbmuxd_connect_request *) s_req;
+		s_req = NULL;
+		goto connect;
+	} else {
+		// send error response and exit
+		if (verbose >= 2)
+			logmsg(LOG_ERR, "%s[%x]: Invalid scan packet received.",
+				   __func__, THREAD);
+		// TODO is this required?!
+		usbmuxd_send_result(cdata->socket, s_req->header.tag, EINVAL);
+		goto leave;
+	}
+
+	pthread_mutex_lock(&usb_mutex);
+	// gather data about all iPhones/iPods attached
+
+	if (verbose >= 5)
+		logmsg(LOG_DEBUG, "%s[%x]: usb init", __func__, THREAD);
+	usb_init();
+	if (verbose >= 5)
+		logmsg(LOG_DEBUG, "%s[%x]: usb find busses", __func__, THREAD);
+	usb_find_busses();
+	if (verbose >= 5)
+		logmsg(LOG_DEBUG, "%s[%x]: usb find devices", __func__, THREAD);
+	usb_find_devices();
+
+	if (verbose >= 2)
+		logmsg(LOG_NOTICE, "%s[%x]: Looking for attached devices...",
+			   __func__, THREAD);
+
+	for (bus = usb_get_busses(); bus; bus = bus->next) {
+		for (dev = bus->devices; dev; dev = dev->next) {
+			if (dev->descriptor.idVendor == 0x05ac
+				&& dev->descriptor.idProduct >= 0x1290
+				&& dev->descriptor.idProduct <= 0x1293) {
+				if (verbose >= 1)
+					logmsg(LOG_NOTICE,
+						   "%s[%x]: Found device on bus %d, id %d",
+						   __func__, THREAD, bus->location, dev->devnum);
+				found++;
+
+				// construct packet
+				memset(&dev_info_rec, 0, sizeof(dev_info_rec));
+				dev_info_rec.header.length = sizeof(dev_info_rec);
+				dev_info_rec.header.type = USBMUXD_DEVICE_INFO;
+				dev_info_rec.device.device_id = dev->devnum;
+				dev_info_rec.device.product_id = dev->descriptor.idProduct;
+				if (dev->descriptor.iSerialNumber) {
+					usb_dev_handle *udev;
+					//pthread_mutex_lock(&usbmux_mutex);
+					udev = usb_open(dev);
+					if (udev) {
+						usb_get_string_simple(udev,
+											  dev->descriptor.
+											  iSerialNumber,
+											  dev_info_rec.device.
+											  serial_number,
+											  sizeof(dev_info_rec.device.
+													 serial_number) + 1);
+						usb_close(udev);
+					}
+					//pthread_mutex_unlock(&usbmux_mutex);
+				}
+#ifdef DEBUG
+				if (verbose >= 4)
+					print_buffer(stderr, (char *) &dev_info_rec,
+								 sizeof(dev_info_rec));
+#endif
+
+				// send it
+				if (send_buf
+					(cdata->socket, &dev_info_rec,
+					 sizeof(dev_info_rec)) <= 0) {
+					if (verbose >= 3)
+						logmsg(LOG_ERR,
+							   "%s[%x]: Error: Could not send device info: %s",
+							   __func__, THREAD, strerror(errno));
+					found--;
+				}
+			}
+		}
+	}
+	pthread_mutex_unlock(&usb_mutex);
+
+	if (found <= 0) {
+		if (verbose >= 1)
+			logmsg(LOG_NOTICE,
+				   "%s[%x]: No attached iPhone/iPod devices found.",
+				   __func__, THREAD);
+		goto leave;
+	}
+
+	if (verbose >= 3)
+		logmsg(LOG_NOTICE, "%s[%x]: Waiting for connect request", __func__,
+			   THREAD);
+
+	// now wait for connect request
+	//memset(&c_req, 0, sizeof(c_req));
+	if ((recv_len =
+		 usbmuxd_get_request(cdata->socket, (void **) &c_req, 0)) <= 0) {
+		if (verbose >= 3)
+			logmsg(LOG_NOTICE,
+				   "%s[%x]: Did not receive any connect request.",
+				   __func__, THREAD);
+		goto leave;
+	}
+
+  connect:
+
+	if (c_req->header.type != USBMUXD_CONNECT) {
+		if (verbose >= 2)
+			logmsg(LOG_ERR,
+				   "%s[%x]: Unexpected packet of type %d received.",
+				   __func__, THREAD, c_req->header.type);
+		goto leave;
+	}
+
+	if (verbose >= 3)
+		logmsg(LOG_NOTICE,
+			   "%s[%x]: Setting up connection to usb device #%d on port %d",
+			   __func__, THREAD, c_req->device_id,
+			   ntohs(c_req->tcp_dport));
+
+	// find the device, and open usb connection
+	pthread_mutex_lock(&usbmux_mutex);
+	phone = NULL;
+	cur_dev = NULL;
+	// first check if we already have an open connection
+	if (devices) {
+		for (i = 0; i < device_count; i++) {
+			if (devices[i]) {
+				if (devices[i]->device_id == c_req->device_id) {
+					devices[i]->use_count++;
+					cur_dev = devices[i];
+					phone = cur_dev->phone;
+					break;
+				}
+			}
+		}
+	}
+	if (!phone) {
+		// if not found, make a new connection
+		if (verbose >= 2)
+			logmsg(LOG_NOTICE,
+				   "%s[%x]: creating new usb connection, device_id=%d",
+				   __func__, THREAD, c_req->device_id);
+
+		pthread_mutex_lock(&usb_mutex);
+		if (usbmux_get_specific_device(0, c_req->device_id, &phone) < 0) {
+			pthread_mutex_unlock(&usb_mutex);
+			pthread_mutex_unlock(&usbmux_mutex);
+			if (verbose >= 1)
+				logmsg(LOG_ERR, "%s[%x]: device_id %d could not be opened",
+					   __func__, THREAD, c_req->device_id);
+			usbmuxd_send_result(cdata->socket, c_req->header.tag, ENODEV);
+			goto leave;
+		}
+		pthread_mutex_unlock(&usb_mutex);
+
+		// create device object
+		if (verbose >= 3)
+			logmsg(LOG_DEBUG, "%s[%x]: add to device list", __func__,
+				   THREAD);
+		cur_dev =
+			(struct device_info *) malloc(sizeof(struct device_info));
+		memset(cur_dev, 0, sizeof(struct device_info));
+		cur_dev->use_count = 1;
+		cur_dev->device_id = c_req->device_id;
+		cur_dev->phone = phone;
+		cur_dev->bulk_reader = 0;
+		pthread_mutex_init(&cur_dev->mutex, NULL);
+		pthread_mutex_init(&cur_dev->writer_mutex, NULL);
+
+		if (verbose >= 3)
+			logmsg(LOG_DEBUG, "%s[%x]: device_count = %d", __func__,
+				   THREAD, device_count);
+
+		// add to list of devices
+		devices =
+			(struct device_info **) realloc(devices,
+											sizeof(struct device_info *) *
+											(device_count + 1));
+		if (devices) {
+			devices[device_count] = cur_dev;
+			device_count++;
+		}
+	} else {
+		if (verbose >= 2)
+			logmsg(LOG_NOTICE,
+				   "%s[%x]: reusing usb connection, device_id=%d",
+				   __func__, THREAD, c_req->device_id);
+	}
+	pthread_mutex_unlock(&usbmux_mutex);
+
+	// setup connection to iPhone/iPod
+//    pthread_mutex_lock(&usbmux_mutex);
+	res =
+		usbmux_new_client(cur_dev->phone, 0, ntohs(c_req->tcp_dport),
+						  &(cdata->muxclient));
+//    pthread_mutex_unlock(&usbmux_mutex);
+
+	if (res != 0) {
+		usbmuxd_send_result(cdata->socket, c_req->header.tag, res);
+		if (verbose >= 1)
+			logmsg(LOG_ERR,
+				   "%s[%x]: mux_new_client returned %d, aborting.",
+				   __func__, THREAD, res);
+		goto leave;
+	}
+	// start bulk reader thread (once per device)
+	pthread_mutex_lock(&cur_dev->mutex);
+	if (cur_dev->bulk_reader == 0) {
+		pthread_create(&cur_dev->bulk_reader, NULL,
+					   usbmuxd_bulk_reader_thread, cur_dev);
+	}
+	pthread_mutex_unlock(&cur_dev->mutex);
+
+	// start connection handler thread
+	cdata->handler_dead = 0;
+	cdata->tag = c_req->header.tag;
+	cdata->dev = cur_dev;
+	if (pthread_create
+		(&cdata->handler, NULL, usbmuxd_client_handler_thread, cdata) != 0)
+	{
+		if (verbose >= 1)
+			logmsg(LOG_ERR,
+				   "%s[%x]: could not create usbmuxd_client_handler_thread!",
+				   __func__, THREAD);
+		cdata->handler = 0;
+		goto leave;
+	}
+	// wait for handler thread to finish its work
+	if (cdata->handler != 0) {
+		pthread_join(cdata->handler, NULL);
+	}
+
+	if (verbose >= 2)
+		logmsg(LOG_NOTICE, "%s[%x]: closing connection", __func__, THREAD);
+
+	// time to clean up
+	if (cdata && cdata->muxclient) {	// should be non-NULL
+		usbmux_free_client(cdata->muxclient);
+	}
+
+  leave:
+	if (verbose >= 3)
+		logmsg(LOG_NOTICE, "%s[%x]: terminating", __func__, THREAD);
+
+	if (s_req) {
+		free(s_req);
+	}
+	if (c_req) {
+		free(c_req);
+	}
+	// this has to be freed only if it's not in use anymore as it closes
+	// the USB connection
+	pthread_mutex_lock(&usbmux_mutex);
+	if (cur_dev) {
+		pthread_mutex_lock(&cur_dev->mutex);
+		if (cur_dev->use_count > 1) {
+			if (verbose >= 2)
+				logmsg(LOG_NOTICE,
+					   "%s[%x]: decreasing device use count (from %d to %d)",
+					   __func__, THREAD, cur_dev->use_count,
+					   cur_dev->use_count - 1);
+			cur_dev->use_count--;
+			pthread_mutex_unlock(&cur_dev->mutex);
+		} else {
+			if (verbose >= 2)
+				logmsg(LOG_NOTICE,
+					   "%s[%x]: last client disconnected, cleaning up",
+					   __func__, THREAD);
+			cur_dev->use_count = 0;
+			pthread_mutex_unlock(&cur_dev->mutex);
+			if (cur_dev->bulk_reader != 0) {
+				if (verbose >= 3)
+					logmsg(LOG_NOTICE, "%s[%x]: joining bulk_reader...",
+						   __func__, THREAD);
+				pthread_join(cur_dev->bulk_reader, NULL);
+			}
+			pthread_mutex_lock(&usb_mutex);
+			usbmux_free_device(cur_dev->phone);
+			pthread_mutex_unlock(&usb_mutex);
+			pthread_mutex_destroy(&cur_dev->writer_mutex);
+			pthread_mutex_destroy(&cur_dev->mutex);
+			free(cur_dev);
+			cur_dev = NULL;
+			if (device_count > 1) {
+				struct device_info **newlist;
+				int j;
+
+				newlist =
+					(struct device_info **)
+					malloc(sizeof(struct device_info *)
+						   * device_count - 1);
+				for (i = 0; i < device_count; i++) {
+					if (devices[i] != NULL) {
+						newlist[j++] = devices[i];
+					}
+				}
+				free(devices);
+				devices = newlist;
+				device_count--;
+			} else {
+				free(devices);
+				devices = NULL;
+				device_count = 0;
+			}
+		}
+	}
+	pthread_mutex_unlock(&usbmux_mutex);
+
+	cdata->dead = 1;
+	close(cdata->socket);
+
+	if (verbose >= 3)
+		logmsg(LOG_NOTICE, "%s[%x]: terminated", __func__, THREAD);
+
+	return NULL;
+}
+
+/**
+ * make this program run detached from the current console
+ */
+static int daemonize()
+{
+	pid_t pid;
+	pid_t sid;
+
+	// already a daemon
+	if (getppid() == 1)
+		return 0;
+
+	pid = fork();
+	if (pid < 0) {
+		exit(EXIT_FAILURE);
+	}
+
+	if (pid > 0) {
+		// exit parent process
+		exit(EXIT_SUCCESS);
+	}
+	// At this point we are executing as the child process
+
+	// Change the file mode mask
+	umask(0);
+
+	// Create a new SID for the child process
+	sid = setsid();
+	if (sid < 0) {
+		return -1;
+	}
+	// Change the current working directory.
+	if ((chdir("/")) < 0) {
+		return -2;
+	}
+	// Redirect standard files to /dev/null
+	freopen("/dev/null", "r", stdin);
+	freopen("/dev/null", "w", stdout);
+	freopen("/dev/null", "w", stderr);
+
+	return 0;
+}
+
+/**
+ * signal handler function for cleaning up properly
+ */
+static void clean_exit(int sig)
+{
+	if (sig == SIGINT) {
+		if (verbose >= 1)
+			fprintf(stderr, "CTRL+C pressed\n");
+	}
+	quit_flag = 1;
+}
+
+static void usage()
+{
+	printf("usage: usbmuxd [options]\n");
+	printf("\t-h|--help        print this message.\n");
+	printf("\t-v|--verbose     be verbose\n");
+	printf("\t-f|--foreground  do not daemonize\n");
+	printf("\n");
+}
+
+static void parse_opts(int argc, char **argv)
+{
+	static struct option longopts[] = {
+		{"help", 0, NULL, 'h'},
+		{"foreground", 0, NULL, 'f'},
+		{"verbose", 0, NULL, 'v'},
+		{"exit-on-no-devices", 0, NULL, 'e'},
+		{NULL, 0, NULL, 0}
+	};
+	int c;
+
+	while (1) {
+		c = getopt_long(argc, argv, "hfve", longopts, (int *) 0);
+		if (c == -1) {
+			break;
+		}
+
+		switch (c) {
+		case 'h':
+			usage();
+			exit(0);
+		case 'f':
+			foreground = 1;
+			break;
+		case 'v':
+			sock_stuff_set_verbose(++verbose);
+			break;
+		case 'e':
+			exit_on_no_devices = 1;
+			break;
+		default:
+			usage();
+			exit(2);
+		}
+	}
+}
+
+/**
+ * checks for attached devices
+ *
+ * @return number of devices found
+ */
+static int devices_attached()
+{
+	struct usb_bus *bus;
+	struct usb_device *dev;
+	int res = 0;
+
+	usb_init();
+	usb_find_busses();
+	usb_find_devices();
+
+	for (bus = usb_get_busses(); bus; bus = bus->next) {
+		for (dev = bus->devices; dev; dev = dev->next) {
+			if (dev->descriptor.idVendor == 0x05ac
+				&& dev->descriptor.idProduct >= 0x1290
+				&& dev->descriptor.idProduct <= 0x1293) {
+				res++;
+			}
+		}
+	}
+
+	return res;
+}
+
+/**
+ * main function. Initializes all stuff and then loops waiting in accept.
+ */
+int main(int argc, char **argv)
+{
+	struct sockaddr_un c_addr;
+	socklen_t len = sizeof(struct sockaddr_un);
+	struct client_data *cdata = NULL;
+	struct client_data **children = NULL;
+	int children_capacity = DEFAULT_CHILDREN_CAPACITY;
+	int i;
+	int result = 0;
+	int cnt = 0;
+	FILE *lfd = NULL;
+	struct flock lock;
+
+	parse_opts(argc, argv);
+
+	argc -= optind;
+	argv += optind;
+
+	if (!foreground) {
+		openlog("usbmuxd", LOG_PID, 0);
+	}
+
+	if (verbose >= 2)
+		logmsg(LOG_NOTICE, "starting");
+
+	// signal(SIGHUP, reload_conf); // none yet
+	signal(SIGINT, clean_exit);
+	signal(SIGQUIT, clean_exit);
+	signal(SIGTERM, clean_exit);
+	signal(SIGPIPE, SIG_IGN);
+
+	// check for other running instance
+	lfd = fopen(LOCKFILE, "r");
+	if (lfd) {
+		lock.l_type = 0;
+		lock.l_whence = SEEK_SET;
+		lock.l_start = 0;
+		lock.l_len = 0;
+		fcntl(fileno(lfd), F_GETLK, &lock);
+		fclose(lfd);
+		if (lock.l_type != F_UNLCK) {
+			logmsg(LOG_NOTICE,
+				   "another instance is already running. exiting.");
+			return -1;
+		}
+	}
+
+	if (exit_on_no_devices) {
+		if (devices_attached() <= 0) {
+			logmsg(LOG_NOTICE, "no devices attached. exiting.");
+			return 0;
+		}
+	}
+
+	fsock = create_unix_socket(USBMUXD_SOCKET_FILE);
+	if (fsock < 0) {
+		logmsg(LOG_ERR, "Could not create socket, exiting");
+		if (!foreground) {
+			closelog();
+		}
+		return -1;
+	}
+
+	chmod(USBMUXD_SOCKET_FILE, 0666);
+
+	if (verbose >= 3)
+		usbmux_set_debug(1);
+
+	if (!foreground) {
+		if (daemonize() < 0) {
+			fprintf(stderr, "usbmuxd: FATAL: Could not daemonize!\n");
+			syslog(LOG_ERR, "FATAL: Could not daemonize!");
+			closelog();
+			exit(EXIT_FAILURE);
+		}
+	}
+	// now open the lockfile and place the lock
+	lfd = fopen(LOCKFILE, "w");
+	if (lfd) {
+		lock.l_type = F_WRLCK;
+		lock.l_whence = SEEK_SET;
+		lock.l_start = 0;
+		lock.l_len = 0;
+		if (fcntl(fileno(lfd), F_SETLK, &lock) == -1) {
+			logmsg(LOG_ERR, "ERROR: lockfile locking failed!");
+		}
+	}
+	// drop elevated privileges
+	if (getuid() == 0 || geteuid() == 0) {
+		struct passwd *pw = getpwnam("nobody");
+		if (pw) {
+			setuid(pw->pw_uid);
+		} else {
+			logmsg(LOG_ERR,
+				   "ERROR: Dropping privileges failed, check if user 'nobody' exists! Will now terminate.");
+			exit(EXIT_FAILURE);
+		}
+
+		// security check
+		if (setuid(0) != -1) {
+			logmsg(LOG_ERR, "ERROR: Failed to drop privileges properly!");
+			exit(EXIT_FAILURE);
+		}
+		if (verbose >= 2)
+			logmsg(LOG_NOTICE, "Successfully dropped privileges");
+	}
+	// Reserve space for 10 clients which should be enough. If not, the
+	// buffer gets enlarged later.
+	children =
+		(struct client_data **) malloc(sizeof(struct client_data *) *
+									   children_capacity);
+	if (!children) {
+		logmsg(LOG_ERR,
+			   "Out of memory when allocating memory for child threads. Terminating.");
+		if (!foreground) {
+			closelog();
+		}
+		exit(EXIT_FAILURE);
+	}
+	memset(children, 0, sizeof(struct client_data *) * children_capacity);
+
+	if (verbose >= 2)
+		logmsg(LOG_NOTICE, "waiting for connection");
+	while (!quit_flag) {
+		// Check the file descriptor before accepting a connection.
+		// If no connection attempt is made, just repeat...
+		result = check_fd(fsock, FD_READ, 1000);
+		if (result <= 0) {
+			if (result == 0) {
+				// cleanup
+				for (i = 0; i < children_capacity; i++) {
+					if (children[i]) {
+						if (children[i]->dead != 0) {
+							pthread_join(children[i]->thread, NULL);
+							if (verbose >= 3)
+								logmsg(LOG_NOTICE,
+									   "reclaimed client thread (fd=%d)",
+									   children[i]->socket);
+							free(children[i]);
+							children[i] = NULL;
+							cnt++;
+						} else {
+							cnt = 0;
+						}
+					} else {
+						cnt++;
+					}
+				}
+
+				if ((children_capacity > DEFAULT_CHILDREN_CAPACITY)
+					&& ((children_capacity - cnt) <=
+						DEFAULT_CHILDREN_CAPACITY)) {
+					children_capacity = DEFAULT_CHILDREN_CAPACITY;
+					children =
+						realloc(children,
+								sizeof(struct client_data *) *
+								children_capacity);
+				}
+				continue;
+			} else {
+				if (verbose >= 3)
+					logmsg(LOG_ERR, "usbmuxd: select error: %s",
+						   strerror(errno));
+				continue;
+			}
+		}
+
+		cdata = (struct client_data *) malloc(sizeof(struct client_data));
+		memset(cdata, 0, sizeof(struct client_data));
+		if (!cdata) {
+			quit_flag = 1;
+			logmsg(LOG_ERR, "Error: Out of memory! Terminating.");
+			break;
+		}
+
+		cdata->socket = accept(fsock, (struct sockaddr *) &c_addr, &len);
+		if (cdata->socket < 0) {
+			free(cdata);
+			if (errno == EINTR) {
+				continue;
+			} else {
+				if (verbose >= 3)
+					logmsg(LOG_ERR, "Error in accept: %s",
+						   strerror(errno));
+				continue;
+			}
+		}
+
+		if (verbose >= 1)
+			logmsg(LOG_NOTICE, "new client connected (fd=%d)",
+				   cdata->socket);
+
+		// create client thread:
+		if (pthread_create
+			(&cdata->thread, NULL, usbmuxd_client_init_thread, cdata) == 0)
+		{
+			for (i = 0; i < children_capacity; i++) {
+				if (children[i] == NULL)
+					break;
+			}
+			if (i == children_capacity) {
+				// enlarge buffer
+				children_capacity++;
+				children =
+					realloc(children,
+							sizeof(struct client_data *) *
+							children_capacity);
+				if (!children) {
+					logmsg(LOG_ERR,
+						   "Out of memory when enlarging child thread buffer");
+				}
+			}
+			children[i] = cdata;
+		} else {
+			logmsg(LOG_ERR, "Failed to create client_init_thread.");
+			close(cdata->socket);
+			free(cdata);
+			cdata = NULL;
+		}
+	}
+
+	if (verbose >= 3)
+		logmsg(LOG_NOTICE, "terminating");
+
+	// preparing for shutdown: wait for child threads to terminate (if any)
+	if (verbose >= 2)
+		logmsg(LOG_NOTICE, "waiting for child threads to terminate...");
+	for (i = 0; i < children_capacity; i++) {
+		if (children[i] != NULL) {
+			pthread_join(children[i]->thread, NULL);
+			free(children[i]);
+		}
+	}
+
+	// delete the children set.
+	free(children);
+	children = NULL;
+
+
+	if (fsock >= 0) {
+		close(fsock);
+	}
+
+	unlink(USBMUXD_SOCKET_FILE);
+
+	// unlock lock file and close it.
+	if (lfd) {
+		lock.l_type = F_UNLCK;
+		fcntl(fileno(lfd), F_SETLK, &lock);
+		fclose(lfd);
+	}
+
+	if (verbose >= 1)
+		logmsg(LOG_NOTICE, "usbmuxd: terminated");
+	if (!foreground) {
+		closelog();
+	}
+
+	return 0;
+}
diff --git a/src/sock_stuff.c b/src/sock_stuff.c
new file mode 100644
index 0000000..b51d6ba
--- /dev/null
+++ b/src/sock_stuff.c
@@ -0,0 +1,298 @@
+#include <stdio.h>
+#include <stddef.h>
+#include <unistd.h>
+#include <errno.h>
+#include <sys/time.h>
+#include <sys/stat.h>
+#include <sys/socket.h>
+#include <sys/un.h>
+#include <netinet/in.h>
+#include <netdb.h>
+#include <arpa/inet.h>
+#include "sock_stuff.h"
+
+#define RECV_TIMEOUT 20000
+
+static int verbose = 0;
+
+void sock_stuff_set_verbose(int level)
+{
+	verbose = level;
+}
+
+int create_unix_socket(const char *filename)
+{
+	struct sockaddr_un name;
+	int sock;
+	size_t size;
+
+	// remove if still present
+	unlink(filename);
+
+	/* Create the socket. */
+	sock = socket(PF_LOCAL, SOCK_STREAM, 0);
+	if (sock < 0) {
+		perror("socket");
+		return -1;
+	}
+
+	/* Bind a name to the socket. */
+	name.sun_family = AF_LOCAL;
+	strncpy(name.sun_path, filename, sizeof(name.sun_path));
+	name.sun_path[sizeof(name.sun_path) - 1] = '\0';
+
+	/* The size of the address is
+	   the offset of the start of the filename,
+	   plus its length,
+	   plus one for the terminating null byte.
+	   Alternatively you can just do:
+	   size = SUN_LEN (&name);
+	 */
+	size = (offsetof(struct sockaddr_un, sun_path)
+			+ strlen(name.sun_path) + 1);
+
+	if (bind(sock, (struct sockaddr *) &name, size) < 0) {
+		perror("bind");
+		close(sock);
+		return -1;
+	}
+
+	if (listen(sock, 10) < 0) {
+		perror("listen");
+		close(sock);
+		return -1;
+	}
+
+	return sock;
+}
+
+int connect_unix_socket(const char *filename)
+{
+	struct sockaddr_un name;
+	int sfd = -1;
+	size_t size;
+	struct stat fst;
+
+	// check if socket file exists...
+	if (stat(filename, &fst) != 0) {
+		if (verbose >= 2)
+			fprintf(stderr, "%s: stat '%s': %s\n", __func__, filename,
+					strerror(errno));
+		return -1;
+	}
+	// ... and if it is a unix domain socket
+	if (!S_ISSOCK(fst.st_mode)) {
+		if (verbose >= 2)
+			fprintf(stderr, "%s: File '%s' is not a socket!\n", __func__,
+					filename);
+		return -1;
+	}
+	// make a new socket
+	if ((sfd = socket(PF_LOCAL, SOCK_STREAM, 0)) < 0) {
+		if (verbose >= 2)
+			fprintf(stderr, "%s: socket: %s\n", __func__, strerror(errno));
+		return -1;
+	}
+	// and connect to 'filename'
+	name.sun_family = AF_LOCAL;
+	strncpy(name.sun_path, filename, sizeof(name.sun_path));
+	name.sun_path[sizeof(name.sun_path) - 1] = 0;
+
+	size = (offsetof(struct sockaddr_un, sun_path)
+			+ strlen(name.sun_path) + 1);
+
+	if (connect(sfd, (struct sockaddr *) &name, size) < 0) {
+		close(sfd);
+		if (verbose >= 2)
+			fprintf(stderr, "%s: connect: %s\n", __func__,
+					strerror(errno));
+		return -1;
+	}
+
+	return sfd;
+}
+
+int create_socket(uint16_t port)
+{
+	int sfd = -1;
+	int yes = 1;
+	struct sockaddr_in saddr;
+
+	if (0 > (sfd = socket(PF_INET, SOCK_STREAM, IPPROTO_TCP))) {
+		perror("socket()");
+		return -1;
+	}
+
+	if (setsockopt(sfd, SOL_SOCKET, SO_REUSEADDR, &yes, sizeof(int)) == -1) {
+		perror("setsockopt()");
+		close(sfd);
+		return -1;
+	}
+
+	memset((void *) &saddr, 0, sizeof(saddr));
+	saddr.sin_family = AF_INET;
+	saddr.sin_addr.s_addr = htonl(INADDR_ANY);
+	saddr.sin_port = htons(port);
+
+	if (0 > bind(sfd, (struct sockaddr *) &saddr, sizeof(saddr))) {
+		perror("bind()");
+		close(sfd);
+		return -1;
+	}
+
+	if (listen(sfd, 1) == -1) {
+		perror("listen()");
+		close(sfd);
+		return -1;
+	}
+
+	return sfd;
+}
+
+int connect_socket(const char *addr, uint16_t port)
+{
+	int sfd = -1;
+	int yes = 1;
+	struct hostent *hp;
+	struct sockaddr_in saddr;
+
+	if (!addr) {
+		errno = EINVAL;
+		return -1;
+	}
+
+	if ((hp = gethostbyname(addr)) == NULL) {
+		if (verbose >= 2)
+			fprintf(stderr, "%s: unknown host '%s'\n", __func__, addr);
+		return -1;
+	}
+
+	if (!hp->h_addr) {
+		if (verbose >= 2)
+			fprintf(stderr, "%s: gethostbyname returned NULL address!\n",
+					__func__);
+		return -1;
+	}
+
+	if (0 > (sfd = socket(PF_INET, SOCK_STREAM, IPPROTO_TCP))) {
+		perror("socket()");
+		return -1;
+	}
+
+	if (setsockopt(sfd, SOL_SOCKET, SO_REUSEADDR, &yes, sizeof(int)) == -1) {
+		perror("setsockopt()");
+		close(sfd);
+		return -1;
+	}
+
+	memset((void *) &saddr, 0, sizeof(saddr));
+	saddr.sin_family = AF_INET;
+	saddr.sin_addr.s_addr = *(uint32_t *) hp->h_addr;
+	saddr.sin_port = htons(port);
+
+	if (connect(sfd, (struct sockaddr *) &saddr, sizeof(saddr)) < 0) {
+		perror("connect");
+		close(sfd);
+		return -2;
+	}
+
+	return sfd;
+}
+
+int check_fd(int fd, fd_mode fdm, unsigned int timeout)
+{
+	fd_set fds;
+	int sret;
+	int eagain;
+	struct timeval to;
+
+	if (fd <= 0) {
+		if (verbose >= 2)
+			fprintf(stderr, "ERROR: invalid fd in check_fd %d\n", fd);
+		return -1;
+	}
+
+	FD_ZERO(&fds);
+	FD_SET(fd, &fds);
+
+	to.tv_sec = (time_t) (timeout / 1000);
+	to.tv_usec = (time_t) ((timeout - (to.tv_sec * 1000)) * 1000);
+
+	sret = -1;
+
+	do {
+		eagain = 0;
+		switch (fdm) {
+		case FD_READ:
+			sret = select(fd + 1, &fds, NULL, NULL, &to);
+			break;
+		case FD_WRITE:
+			sret = select(fd + 1, NULL, &fds, NULL, &to);
+			break;
+		case FD_EXCEPT:
+			sret = select(fd + 1, NULL, NULL, &fds, &to);
+			break;
+		default:
+			return -1;
+		}
+
+		if (sret < 0) {
+			switch (errno) {
+			case EINTR:
+				// interrupt signal in select
+				if (verbose >= 2)
+					fprintf(stderr, "%s: EINTR\n", __func__);
+				eagain = 1;
+				break;
+			case EAGAIN:
+				if (verbose >= 2)
+					fprintf(stderr, "%s: EAGAIN\n", __func__);
+				break;
+			default:
+				if (verbose >= 2)
+					fprintf(stderr, "%s: select failed: %s\n", __func__,
+							strerror(errno));
+				return -1;
+			}
+		}
+	} while (eagain);
+
+	return sret;
+}
+
+int recv_buf(int fd, void *data, size_t length)
+{
+	return recv_buf_timeout(fd, data, length, 0, RECV_TIMEOUT);
+}
+
+int peek_buf(int fd, void *data, size_t length)
+{
+	return recv_buf_timeout(fd, data, length, MSG_PEEK, RECV_TIMEOUT);
+}
+
+int recv_buf_timeout(int fd, void *data, size_t length, int flags,
+					 unsigned int timeout)
+{
+	int res;
+	int result;
+
+	// check if data is available
+	res = check_fd(fd, FD_READ, timeout);
+	if (res <= 0) {
+		return res;
+	}
+	// if we get here, there _is_ data available
+	result = recv(fd, data, length, flags);
+	if (res > 0 && result == 0) {
+		// but this is an error condition
+		if (verbose >= 3)
+			fprintf(stderr, "%s: fd=%d recv returned 0\n", __func__, fd);
+		return -1;
+	}
+	return result;
+}
+
+int send_buf(int fd, void *data, size_t length)
+{
+	return send(fd, data, length, 0);
+}
diff --git a/src/sock_stuff.h b/src/sock_stuff.h
new file mode 100644
index 0000000..190f7e1
--- /dev/null
+++ b/src/sock_stuff.h
@@ -0,0 +1,28 @@
+#ifndef __SOCK_STUFF_H
+#define __SOCK_STUFF_H
+
+#include <stdint.h>
+
+enum fd_mode {
+	FD_READ,
+	FD_WRITE,
+	FD_EXCEPT
+};
+typedef enum fd_mode fd_mode;
+
+int create_unix_socket(const char *filename);
+int connect_unix_socket(const char *filename);
+int create_socket(uint16_t port);
+int connect_socket(const char *addr, uint16_t port);
+int check_fd(int fd, fd_mode fdm, unsigned int timeout);
+
+int recv_buf(int fd, void *data, size_t size);
+int peek_buf(int fd, void *data, size_t size);
+int recv_buf_timeout(int fd, void *data, size_t size, int flags,
+					 unsigned int timeout);
+
+int send_buf(int fd, void *data, size_t size);
+
+void sock_stuff_set_verbose(int level);
+
+#endif							/* __SOCK_STUFF_H */
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;
+}
diff --git a/src/usbmux.h b/src/usbmux.h
new file mode 100644
index 0000000..2bcdb15
--- /dev/null
+++ b/src/usbmux.h
@@ -0,0 +1,51 @@
+/*
+ * 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 
+ */
+
+#ifndef __USBMUX_H__
+#define __USBMUX_H__
+
+#include <stdint.h>
+#include <sys/types.h>
+//#include <sys/stat.h>
+
+
+void usbmux_set_debug(int e);
+
+struct usbmux_device_int;
+typedef struct usbmux_device_int *usbmux_device_t;
+
+struct usbmux_client_int;
+typedef struct usbmux_client_int *usbmux_client_t;
+
+int usbmux_get_device ( usbmux_device_t *device );
+int usbmux_get_specific_device(int bus_n, int dev_n, usbmux_device_t * device);
+int usbmux_free_device ( usbmux_device_t device );
+
+
+int usbmux_new_client ( usbmux_device_t device, uint16_t src_port, uint16_t dst_port, usbmux_client_t *client );
+int usbmux_free_client ( usbmux_client_t client );
+
+int usbmux_send(usbmux_client_t client, const char *data, uint32_t datalen, uint32_t * sent_bytes);
+
+int usbmux_recv_timeout(usbmux_client_t client, char *data, uint32_t datalen, uint32_t * recv_bytes, int timeout);
+
+int usbmux_pullbulk(usbmux_device_t device);
+
+int usbmux_get_error(usbmux_client_t client);
+
+#endif
diff --git a/src/usbmuxd-proto.h b/src/usbmuxd-proto.h
new file mode 100644
index 0000000..7f8c2d6
--- /dev/null
+++ b/src/usbmuxd-proto.h
@@ -0,0 +1,52 @@
+/* Protocol defintion for usbmuxd proxy protocol */
+
+#ifndef __USBMUXD_PROTO_H
+#define __USBMUXD_PROTO_H
+
+#include <stdint.h>
+
+#define USBMUXD_SOCKET_FILE "/var/run/usbmuxd"
+
+struct usbmuxd_header {
+	uint32_t length;    // length of message, including header
+	uint32_t reserved;  // always zero
+	uint32_t type;      // message type
+	uint32_t tag;       // responses to this query will echo back this tag
+} __attribute__((__packed__));
+
+struct usbmuxd_result {
+	struct usbmuxd_header header;
+	uint32_t result;
+} __attribute__((__packed__));
+
+struct	usbmuxd_connect_request {
+	struct usbmuxd_header header;
+	uint32_t device_id;
+	uint16_t tcp_dport;   // TCP port number
+	uint16_t reserved;   // set to zero
+} __attribute__((__packed__));
+
+struct usbmuxd_device {
+	uint32_t device_id;
+	uint16_t product_id;
+	char serial_number[40];
+} __attribute__((__packed__));
+
+struct usbmuxd_device_info_record {
+	struct usbmuxd_header header;
+	struct usbmuxd_device device;
+	char padding[222];
+} __attribute__((__packed__));
+
+struct usbmuxd_scan_request {
+	struct usbmuxd_header header;
+} __attribute__((__packed__));
+
+enum {
+	USBMUXD_RESULT  = 1,
+	USBMUXD_CONNECT = 2,
+	USBMUXD_SCAN = 3,
+	USBMUXD_DEVICE_INFO = 4,
+};
+
+#endif /* __USBMUXD_PROTO_H */
diff --git a/src/usbmuxd.h b/src/usbmuxd.h
new file mode 100644
index 0000000..15e97ee
--- /dev/null
+++ b/src/usbmuxd.h
@@ -0,0 +1,45 @@
+#ifndef __USBMUXD_H
+#define __USBMUXD_H
+
+/**
+ * Array entry returned by 'usbmuxd_scan()' scanning.
+ *
+ * If more than one device is available, 'product_id' and
+ * 'serial_number' and be analysed to help make a selection.
+ * The relevant 'handle' should be passed to 'usbmuxd_connect()', to
+ * start a proxy connection.  The value 'handle' should be considered
+ * opaque and no presumption made about the meaning of its value.
+ */
+typedef struct {
+	int handle;
+	int product_id;
+	char serial_number[41];
+} usbmuxd_scan_result;
+
+/**
+ * Contacts usbmuxd and performs a scan for connected devices.
+ *
+ * @param available_devices pointer to array of usbmuxd_scan_result.
+ * 	Array of available devices.  The required 'handle'
+ *	should be passed to 'usbmuxd_connect()'.  The returned array
+ *	is zero-terminated for convenience; the final (unused)
+ *	entry containing handle == 0.  The returned array pointer
+ *	should be freed by passing to 'free()' after use.
+ *
+ * @return number of available devices, zero on no devices, or negative on error
+ */
+int usbmuxd_scan(usbmuxd_scan_result **available_devices);
+
+/**
+ * Request proxy connect to 
+ *
+ * @param handle returned by 'usbmuxd_scan()'
+ *
+ * @param tcp_port TCP port number on device, in range 0-65535.
+ *	common values are 62078 for lockdown, and 22 for SSH.
+ *
+ * @return file descriptor socket of the connection, or -1 on error
+ */
+int usbmuxd_connect(const int handle, const unsigned short tcp_port);
+
+#endif /* __USBMUXD_H */