[PATCH 1/6] Basic PPP protocol support

[Kristen Carlson Accardi <kristen@linux.intel.com>]

[-- Attachment #1: Type: text/plain, Size: 22852 bytes --]

This patch implements the basic PPP protocol.  LCP, NCP etc. are handled in 
a different patch.
---
 Makefile.am      |    4 +-
 gatchat/gatppp.c |  133 ++++++++++++++++
 gatchat/gatppp.h |   58 +++++++
 gatchat/ppp.c    |  454 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
 gatchat/ppp.h    |  130 ++++++++++++++++
 5 files changed, 778 insertions(+), 1 deletions(-)
 create mode 100644 gatchat/gatppp.c
 create mode 100644 gatchat/gatppp.h
 create mode 100644 gatchat/ppp.c
 create mode 100644 gatchat/ppp.h

diff --git a/Makefile.am b/Makefile.am
index eca8eee..6891d16 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -55,7 +55,9 @@ gatchat_sources = gatchat/gatchat.h gatchat/gatchat.c \
 				gatchat/gattty.h gatchat/gattty.c \
 				gatchat/gatutil.h gatchat/gatutil.c \
 				gatchat/gat.h \
-				gatchat/gatserver.h gatchat/gatserver.c
+				gatchat/gatserver.h gatchat/gatserver.c \
+				gatchat/gatppp.c gatchat/gatppp.h \
+				gatchat/ppp.c gatchat/ppp.h
 
 udev_files = plugins/ofono.rules
 
diff --git a/gatchat/gatppp.c b/gatchat/gatppp.c
new file mode 100644
index 0000000..7b68ff3
--- /dev/null
+++ b/gatchat/gatppp.c
@@ -0,0 +1,133 @@
+/*
+ *
+ *  PPP library with GLib integration
+ *
+ *  Copyright (C) 2009-2010  Intel Corporation. All rights reserved.
+ *
+ *  This program is free software; you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License version 2 as
+ *  published by the Free Software Foundation.
+ *
+ *  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 St, Fifth Floor, Boston, MA  02110-1301  USA
+ *
+ */
+
+#ifdef HAVE_CONFIG_H
+#include <config.h>
+#endif
+
+#include <stdio.h>
+#include <fcntl.h>
+#include <unistd.h>
+#include <string.h>
+#include <termios.h>
+#include <arpa/inet.h>
+
+#include <glib.h>
+
+#include "gatutil.h"
+#include "gatppp.h"
+#include "ppp.h"
+
+/* Administrative Open */
+void g_at_ppp_open(GAtPPP *ppp)
+{
+	/* send an OPEN event to the lcp layer */
+}
+
+void g_at_ppp_set_connect_function(GAtPPP *ppp,
+			       GAtPPPConnectFunc callback, gpointer user_data)
+{
+	ppp->connect_cb = callback;
+	ppp->connect_data = user_data;
+}
+
+void g_at_ppp_set_disconnect_function(GAtPPP *ppp,
+				  GAtPPPDisconnectFunc callback,
+				  gpointer user_data)
+{
+	ppp->disconnect_cb = callback;
+	ppp->disconnect_data = user_data;
+}
+
+void g_at_ppp_shutdown(GAtPPP *ppp)
+{
+	/* close the ppp */
+	ppp_close(ppp);
+
+	/* clean up all the queues */
+	g_queue_free(ppp->event_queue);
+	g_queue_free(ppp->recv_queue);
+
+	/* cleanup modem channel */
+	g_source_remove(ppp->modem_watch);
+	g_io_channel_unref(ppp->modem);
+}
+
+void g_at_ppp_ref(GAtPPP *ppp)
+{
+	g_atomic_int_inc(&ppp->ref_count);
+}
+
+void g_at_ppp_unref(GAtPPP *ppp)
+{
+	if (g_atomic_int_dec_and_test(&ppp->ref_count)) {
+		g_at_ppp_shutdown(ppp);
+		g_free(ppp);
+	}
+}
+
+GAtPPP *g_at_ppp_new(GIOChannel *modem)
+{
+	GAtPPP *ppp;
+
+	ppp = g_try_malloc0(sizeof(GAtPPP));
+	if (!ppp)
+		return NULL;
+
+	ppp->modem = g_io_channel_ref(modem);
+	if (!g_at_util_setup_io(ppp->modem, G_IO_FLAG_NONBLOCK)) {
+		g_io_channel_unref(modem);
+		g_free(ppp);
+		return NULL;
+	}
+	g_io_channel_set_buffered(modem, FALSE);
+
+	ppp->ref_count = 1;
+
+	/* set options to defaults */
+	ppp->mru = DEFAULT_MRU;
+	ppp->recv_accm = DEFAULT_ACCM;
+	ppp->xmit_accm[0] = DEFAULT_ACCM;
+	ppp->xmit_accm[3] = 0x60000000; /* 0x7d, 0x7e */
+	ppp->pfc = FALSE;
+	ppp->acfc = FALSE;
+
+	/* allocate the queues */
+	ppp->event_queue = g_queue_new();
+	ppp->recv_queue = g_queue_new();
+
+	ppp->index = 0;
+
+	/* initialize the lcp state */
+
+
+	/* initialize the autentication state */
+
+
+	/* intialize the network state */
+
+	/* start listening for packets from the modem */
+	ppp->modem_watch = g_io_add_watch(modem,
+			G_IO_IN | G_IO_HUP | G_IO_ERR | G_IO_NVAL,
+			ppp_cb, ppp);
+
+	return ppp;
+}
diff --git a/gatchat/gatppp.h b/gatchat/gatppp.h
new file mode 100644
index 0000000..0d5d5cc
--- /dev/null
+++ b/gatchat/gatppp.h
@@ -0,0 +1,58 @@
+/*
+ *
+ *  PPP library with GLib integration
+ *
+ *  Copyright (C) 2009-2010  Intel Corporation. All rights reserved.
+ *
+ *  This program is free software; you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License version 2 as
+ *  published by the Free Software Foundation.
+ *
+ *  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 St, Fifth Floor, Boston, MA  02110-1301  USA
+ *
+ */
+
+#ifndef __G_AT_PPP_H
+#define __G_AT_PPP_H
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+struct _GAtPPP;
+typedef struct _GAtPPP GAtPPP;
+
+typedef enum _GAtPPPConnectStatus {
+	G_AT_PPP_CONNECT_SUCCESS,
+	G_AT_PPP_CONNECT_FAIL
+} GAtPPPConnectStatus;
+
+typedef void (*GAtPPPConnectFunc)(GAtPPP *ppp, GAtPPPConnectStatus success,
+				 guint32 ip_address,
+				 guint32 dns1, guint32 dns2,
+				 gpointer user_data);
+
+typedef void (*GAtPPPDisconnectFunc)(GAtPPP *ppp, gpointer user_data);
+
+GAtPPP * g_at_ppp_new(GIOChannel *modem);
+void g_at_ppp_open(GAtPPP *ppp);
+void g_at_ppp_set_connect_function(GAtPPP *ppp,
+			       GAtPPPConnectFunc callback, gpointer user_data);
+void g_at_ppp_set_disconnect_function(GAtPPP *ppp,
+				  GAtPPPDisconnectFunc callback,
+				  gpointer user_data);
+void g_at_ppp_shutdown(GAtPPP *ppp);
+void g_at_ppp_ref(GAtPPP *ppp);
+void g_at_ppp_unref(GAtPPP *ppp);
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* __G_AT_PPP_H */
diff --git a/gatchat/ppp.c b/gatchat/ppp.c
new file mode 100644
index 0000000..db20d51
--- /dev/null
+++ b/gatchat/ppp.c
@@ -0,0 +1,454 @@
+/*
+ *
+ *  PPP library with GLib integration
+ *
+ *  Copyright (C) 2009-2010  Intel Corporation. All rights reserved.
+ *
+ *  This program is free software; you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License version 2 as
+ *  published by the Free Software Foundation.
+ *
+ *  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 St, Fifth Floor, Boston, MA  02110-1301  USA
+ *
+ */
+
+#ifdef HAVE_CONFIG_H
+#include <config.h>
+#endif
+
+#include <stdio.h>
+#include <fcntl.h>
+#include <unistd.h>
+#include <string.h>
+#include <termios.h>
+#include <arpa/inet.h>
+
+#include <glib.h>
+
+#include "gatutil.h"
+#include "gatppp.h"
+#include "ppp.h"
+
+#define PPPINITFCS16    0xffff  /* Initial FCS value */
+#define PPPGOODFCS16    0xf0b8  /* Good final FCS value */
+
+static GList *packet_handlers = NULL;
+
+void ppp_register_packet_handler(struct ppp_packet_handler *handler)
+{
+	packet_handlers = g_list_append(packet_handlers, handler);
+}
+
+/*
+ * FCS lookup table copied from rfc1662.
+ */
+static guint16 fcstab[256] = {
+	0x0000, 0x1189, 0x2312, 0x329b, 0x4624, 0x57ad, 0x6536, 0x74bf,
+	0x8c48, 0x9dc1, 0xaf5a, 0xbed3, 0xca6c, 0xdbe5, 0xe97e, 0xf8f7,
+	0x1081, 0x0108, 0x3393, 0x221a, 0x56a5, 0x472c, 0x75b7, 0x643e,
+	0x9cc9, 0x8d40, 0xbfdb, 0xae52, 0xdaed, 0xcb64, 0xf9ff, 0xe876,
+	0x2102, 0x308b, 0x0210, 0x1399, 0x6726, 0x76af, 0x4434, 0x55bd,
+	0xad4a, 0xbcc3, 0x8e58, 0x9fd1, 0xeb6e, 0xfae7, 0xc87c, 0xd9f5,
+	0x3183, 0x200a, 0x1291, 0x0318, 0x77a7, 0x662e, 0x54b5, 0x453c,
+	0xbdcb, 0xac42, 0x9ed9, 0x8f50, 0xfbef, 0xea66, 0xd8fd, 0xc974,
+	0x4204, 0x538d, 0x6116, 0x709f, 0x0420, 0x15a9, 0x2732, 0x36bb,
+	0xce4c, 0xdfc5, 0xed5e, 0xfcd7, 0x8868, 0x99e1, 0xab7a, 0xbaf3,
+	0x5285, 0x430c, 0x7197, 0x601e, 0x14a1, 0x0528, 0x37b3, 0x263a,
+	0xdecd, 0xcf44, 0xfddf, 0xec56, 0x98e9, 0x8960, 0xbbfb, 0xaa72,
+	0x6306, 0x728f, 0x4014, 0x519d, 0x2522, 0x34ab, 0x0630, 0x17b9,
+	0xef4e, 0xfec7, 0xcc5c, 0xddd5, 0xa96a, 0xb8e3, 0x8a78, 0x9bf1,
+	0x7387, 0x620e, 0x5095, 0x411c, 0x35a3, 0x242a, 0x16b1, 0x0738,
+	0xffcf, 0xee46, 0xdcdd, 0xcd54, 0xb9eb, 0xa862, 0x9af9, 0x8b70,
+	0x8408, 0x9581, 0xa71a, 0xb693, 0xc22c, 0xd3a5, 0xe13e, 0xf0b7,
+	0x0840, 0x19c9, 0x2b52, 0x3adb, 0x4e64, 0x5fed, 0x6d76, 0x7cff,
+	0x9489, 0x8500, 0xb79b, 0xa612, 0xd2ad, 0xc324, 0xf1bf, 0xe036,
+	0x18c1, 0x0948, 0x3bd3, 0x2a5a, 0x5ee5, 0x4f6c, 0x7df7, 0x6c7e,
+	0xa50a, 0xb483, 0x8618, 0x9791, 0xe32e, 0xf2a7, 0xc03c, 0xd1b5,
+	0x2942, 0x38cb, 0x0a50, 0x1bd9, 0x6f66, 0x7eef, 0x4c74, 0x5dfd,
+	0xb58b, 0xa402, 0x9699, 0x8710, 0xf3af, 0xe226, 0xd0bd, 0xc134,
+	0x39c3, 0x284a, 0x1ad1, 0x0b58, 0x7fe7, 0x6e6e, 0x5cf5, 0x4d7c,
+	0xc60c, 0xd785, 0xe51e, 0xf497, 0x8028, 0x91a1, 0xa33a, 0xb2b3,
+	0x4a44, 0x5bcd, 0x6956, 0x78df, 0x0c60, 0x1de9, 0x2f72, 0x3efb,
+	0xd68d, 0xc704, 0xf59f, 0xe416, 0x90a9, 0x8120, 0xb3bb, 0xa232,
+	0x5ac5, 0x4b4c, 0x79d7, 0x685e, 0x1ce1, 0x0d68, 0x3ff3, 0x2e7a,
+	0xe70e, 0xf687, 0xc41c, 0xd595, 0xa12a, 0xb0a3, 0x8238, 0x93b1,
+	0x6b46, 0x7acf, 0x4854, 0x59dd, 0x2d62, 0x3ceb, 0x0e70, 0x1ff9,
+	0xf78f, 0xe606, 0xd49d, 0xc514, 0xb1ab, 0xa022, 0x92b9, 0x8330,
+	0x7bc7, 0x6a4e, 0x58d5, 0x495c, 0x3de3, 0x2c6a, 0x1ef1, 0x0f78
+};
+
+/*
+ * Calculate a new fcs given the current fcs and the new data.
+ * copied from rfc1662
+ *
+ *     The FCS field is calculated over all bits of the Address, Control,
+ *     Protocol, Information and Padding fields, not including any start
+ *     and stop bits (asynchronous) nor any bits (synchronous) or octets
+ *     (asynchronous or synchronous) inserted for transparency.  This
+ *     also does not include the Flag Sequences nor the FCS field itself.
+ */
+static guint16 ppp_fcs(guint16 fcs, guint8 c)
+{
+	guint16 new_fcs;
+
+	new_fcs = (fcs >> 8) ^ fcstab[(fcs ^ c) & 0xff];
+	return new_fcs;
+}
+
+/*
+ * escape any chars less than 0x20, and check the transmit accm table to
+ * see if this character should be escaped.
+ */
+static gboolean ppp_escape(GAtPPP *ppp, guint8 c, gboolean lcp)
+{
+	if ((lcp && c < 0x20) || (ppp->xmit_accm[c >> 5] & (1 << (c & 0x1f))))
+		return TRUE;
+	return FALSE;
+}
+
+static void ppp_put(GAtPPP *ppp, guint8 *buf, int *pos,
+			guint8 c, gboolean lcp)
+{
+	int i = *pos;
+
+	/* escape characters if needed,  copy into buf, increment pos */
+	if (ppp_escape(ppp, c, lcp)) {
+		buf[i++] = PPP_ESC;
+		buf[i++] = c ^ 0x20;
+	} else
+		buf[i++] = c;
+	*pos = i;
+}
+
+/* XXX implement PFC and ACFC */
+static guint8 *ppp_encode(GAtPPP *ppp, guint8 *data, int len,
+				guint *newlen)
+{
+	int pos = 0;
+	int i = 0;
+	guint16 fcs = PPPINITFCS16;
+	guint16 proto = get_host_short(data);
+	gboolean lcp = (proto == LCP_PROTOCOL);
+	guint8 *frame = g_try_malloc0(BUFFERSZ);
+	if (!frame)
+		return NULL;
+
+	/* copy in the HDLC framing */
+	frame[pos++] = PPP_FLAG_SEQ;
+
+	/* from here till end flag, calculate FCS over each character */
+	fcs = ppp_fcs(fcs, PPP_ADDR_FIELD);
+	ppp_put(ppp, frame, &pos, PPP_ADDR_FIELD, lcp);
+	fcs = ppp_fcs(fcs, PPP_CTRL);
+	ppp_put(ppp, frame, &pos, PPP_CTRL, lcp);
+
+	/*
+	 * for each byte, first calculate FCS, then do escaping if
+	 * neccessary
+	 */
+	while (len--) {
+		fcs = ppp_fcs(fcs, data[i]);
+		ppp_put(ppp, frame, &pos, data[i++], lcp);
+	}
+
+	/* add FCS */
+	fcs ^= 0xffff;                 /* complement */
+	ppp_put(ppp, frame, &pos, (guint8)(fcs & 0x00ff), lcp);
+	ppp_put(ppp, frame, &pos, (guint8)((fcs >> 8) & 0x00ff), lcp);
+
+	/* add flag */
+	frame[pos++] = PPP_FLAG_SEQ;
+
+	*newlen = pos;
+	return frame;
+}
+
+static gint is_proto_handler(gconstpointer a, gconstpointer b)
+{
+	const struct ppp_packet_handler *h = a;
+	const guint16 proto = (guint16) GPOINTER_TO_UINT(b);
+
+	if (h->proto == proto)
+		return 0;
+	else
+		return -1;
+}
+
+/* called when we have received a complete ppp frame */
+static void ppp_recv(GAtPPP *ppp)
+{
+	guint16 protocol;
+	guint8 *frame, *packet;
+	GList *list;
+	struct ppp_packet_handler *h;
+
+	/* pop frames off of receive queue */
+	while ((frame = g_queue_pop_head(ppp->recv_queue))) {
+		protocol = ppp_proto(frame);
+		packet = ppp_info(frame);
+
+		/*
+		 * check to see if we have a protocol handler
+		 * registered for this packet
+		 */
+		list = g_list_find_custom(packet_handlers,
+				GUINT_TO_POINTER(protocol),
+				is_proto_handler);
+		if (list) {
+			h = list->data;
+			h->handler(h->priv, packet);
+		}
+		g_free(frame);
+	}
+}
+
+/* XXX - Implement PFC and ACFC */
+static guint8 *ppp_decode(GAtPPP *ppp, guint8 *frame)
+{
+	guint8 *data;
+	guint pos = 0;
+	int i = 0;
+	int len;
+	guint16 fcs;
+
+	data = g_try_malloc0(ppp->mru + 10);
+	if (!data)
+		return NULL;
+
+	/* skip the first flag char */
+	pos++;
+
+	/* TBD - how to deal with recv_accm */
+	while (frame[pos] != PPP_FLAG_SEQ) {
+		/* scan for escape character */
+		if (frame[pos] == PPP_ESC) {
+			/* skip that char */
+			pos++;
+			data[i] = frame[pos] ^ 0x20;
+		} else
+			data[i] = frame[pos];
+		i++; pos++;
+	}
+
+	len = i;
+
+	/* see if we have a good FCS */
+	fcs = PPPINITFCS16;
+	for (i = 0; i < len; i++)
+		fcs = ppp_fcs(fcs, data[i]);
+
+	if (fcs != PPPGOODFCS16) {
+		g_free(data);
+		return NULL;
+	}
+	return data;
+}
+
+static void ppp_feed(GAtPPP *ppp, guint8 *data, gsize len)
+{
+	guint pos = 0;
+	guint8 *frame;
+
+	/* collect bytes until we detect we have received a complete frame */
+	/* examine the data.  If we are@the beginning of a new frame,
+	 * allocate memory to buffer the frame.
+	 */
+
+	for (pos = 0; pos < len; pos++) {
+		if (data[pos] == PPP_FLAG_SEQ) {
+			if (ppp->index != 0) {
+				/* store last flag character & decode */
+				ppp->buffer[ppp->index++] = data[pos];
+				frame = ppp_decode(ppp, ppp->buffer);
+
+				/* push decoded frame onto receive queue */
+				if (frame)
+					g_queue_push_tail(ppp->recv_queue,
+								frame);
+
+				/* zero buffer */
+				memset(ppp->buffer, 0, BUFFERSZ);
+				ppp->index = 0;
+				continue;
+			}
+		}
+		/* copy byte to buffer */
+		if (ppp->index < BUFFERSZ)
+			ppp->buffer[ppp->index++] = data[pos];
+	}
+	/* process receive queue */
+	ppp_recv(ppp);
+}
+
+/*
+ * transmit out through the lower layer interface
+ *
+ * infolen - length of the information part of the packet
+ */
+void ppp_transmit(GAtPPP *ppp, guint8 *packet, guint infolen)
+{
+	guint8 *frame;
+	guint framelen;
+	GError *error = NULL;
+	GIOStatus status;
+	gsize bytes_written;
+
+	/*
+	 * do the octet stuffing.  Add 2 bytes to the infolen to
+	 * include the protocol field.
+	 */
+	frame = ppp_encode(ppp, packet, infolen + 2, &framelen);
+	if (!frame) {
+		g_printerr("Failed to encode packet to transmit\n");
+		return;
+	}
+
+	/* transmit through the lower layer interface */
+	/*
+	 * TBD - should we just put this on a queue and transmit when
+	 * we won't block, or allow ourselves to block here?
+	 */
+	status = g_io_channel_write_chars(ppp->modem, (gchar *) frame,
+                                          framelen, &bytes_written, &error);
+
+	g_free(frame);
+}
+
+gboolean ppp_cb(GIOChannel *channel, GIOCondition cond, gpointer data)
+{
+	GAtPPP *ppp = data;
+	GIOStatus status;
+	gchar buf[256];
+	gsize bytes_read;
+	GError *error = NULL;
+
+	if (cond & (G_IO_NVAL | G_IO_ERR | G_IO_HUP)) {
+		g_print("G_IO_NVAL | G_IO_ERR");
+		return FALSE;
+	}
+
+	if (cond & G_IO_IN) {
+		status = g_io_channel_read_chars(channel, buf, 256,
+				&bytes_read, &error);
+		if (bytes_read > 0)
+			ppp_feed(ppp, (guint8 *)buf, bytes_read);
+		if (status != G_IO_STATUS_NORMAL && status != G_IO_STATUS_AGAIN)
+			return FALSE;
+	}
+
+	return TRUE;
+}
+
+/* Administrative Close */
+void ppp_close(GAtPPP *ppp)
+{
+	/* send a CLOSE event to the lcp layer */
+}
+
+static void ppp_link_establishment(GAtPPP *ppp)
+{
+	/* signal UP event to LCP */
+}
+
+static void ppp_terminate(GAtPPP *ppp)
+{
+	/* signal DOWN event to LCP */
+}
+
+static void ppp_authenticate(GAtPPP *ppp)
+{
+	/* we don't do authentication right now, so send NONE */
+	if (!ppp->auth_proto)
+		ppp_generate_event(ppp, PPP_NONE);
+	/* otherwise we need to wait for the peer to send us a challenge */
+}
+
+static void ppp_dead(GAtPPP *ppp)
+{
+	/* re-initialize everything */
+}
+
+static void ppp_network(GAtPPP *ppp)
+{
+	/* bring network phase up */
+}
+
+static void ppp_transition_phase(GAtPPP *ppp, enum ppp_phase phase)
+{
+	/* don't do anything if we're already there */
+	if (ppp->phase == phase)
+		return;
+
+	/* set new phase */
+	ppp->phase = phase;
+
+	switch (phase) {
+	case PPP_ESTABLISHMENT:
+		ppp_link_establishment(ppp);
+		break;
+	case PPP_AUTHENTICATION:
+		ppp_authenticate(ppp);
+		break;
+	case PPP_TERMINATION:
+		ppp_terminate(ppp);
+		break;
+	case PPP_DEAD:
+		ppp_dead(ppp);
+		break;
+	case PPP_NETWORK:
+		ppp_network(ppp);
+		break;
+	}
+
+}
+
+static void ppp_handle_event(GAtPPP *ppp)
+{
+	enum ppp_event event;
+
+	while ((event = GPOINTER_TO_UINT(g_queue_pop_head(ppp->event_queue)))){
+		switch (event) {
+		case PPP_UP:
+			/* causes transition to ppp establishment */
+			ppp_transition_phase(ppp, PPP_ESTABLISHMENT);
+			break;
+		case PPP_OPENED:
+			ppp_transition_phase(ppp, PPP_AUTHENTICATION);
+			break;
+		case PPP_CLOSING:
+			/* causes transition to termination phase */
+			ppp_transition_phase(ppp, PPP_TERMINATION);
+			break;
+		case PPP_DOWN:
+			/* cases transition to dead phase */
+			ppp_transition_phase(ppp, PPP_DEAD);
+			break;
+		case PPP_NONE:
+		case PPP_SUCCESS:
+			/* causes transition to network phase */
+			ppp_transition_phase(ppp, PPP_NETWORK);
+			break;
+		case PPP_FAIL:
+			if (ppp->phase == PPP_ESTABLISHMENT)
+				ppp_transition_phase(ppp, PPP_DEAD);
+			else if (ppp->phase == PPP_AUTHENTICATION)
+				ppp_transition_phase(ppp, PPP_TERMINATION);
+		}
+	}
+}
+
+/*
+ * send the event handler a new event to process
+ */
+void ppp_generate_event(GAtPPP *ppp, enum ppp_event event)
+{
+	g_queue_push_tail(ppp->event_queue, GUINT_TO_POINTER(event));
+	ppp_handle_event(ppp);
+}
diff --git a/gatchat/ppp.h b/gatchat/ppp.h
new file mode 100644
index 0000000..573c967
--- /dev/null
+++ b/gatchat/ppp.h
@@ -0,0 +1,130 @@
+/*
+ *
+ *  PPP library with GLib integration
+ *
+ *  Copyright (C) 2009-2010  Intel Corporation. All rights reserved.
+ *
+ *  This program is free software; you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License version 2 as
+ *  published by the Free Software Foundation.
+ *
+ *  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 St, Fifth Floor, Boston, MA  02110-1301  USA
+ *
+ */
+#define DEFAULT_MRU	1500
+#define BUFFERSZ	DEFAULT_MRU*2
+#define DEFAULT_ACCM	0x00000000
+#define PPP_ESC		0x7d
+#define PPP_FLAG_SEQ 	0x7e
+#define PPP_ADDR_FIELD	0xff
+#define PPP_CTRL	0x03
+#define LCP_PROTOCOL	0xc021
+#define CHAP_PROTOCOL	0xc223
+#define PPP_HEADROOM	2
+#define HDLC_HEADROOM	3
+#define HDLC_TAIL	3
+#define MD5		5
+
+enum ppp_phase {
+	PPP_DEAD = 0,
+	PPP_ESTABLISHMENT,
+	PPP_AUTHENTICATION,
+	PPP_NETWORK,
+	PPP_TERMINATION,
+};
+
+enum ppp_event {
+	PPP_UP = 1,
+	PPP_OPENED,
+	PPP_SUCCESS,
+	PPP_NONE,
+	PPP_CLOSING,
+	PPP_FAIL,
+	PPP_DOWN
+};
+
+struct ppp_packet_handler {
+	guint16 proto;
+	void (*handler)(gpointer priv, guint8 *packet);
+	gpointer priv;
+};
+
+struct ppp_header {
+	guint16 proto;
+	guint8 info[0];
+} __attribute__((packed));
+
+struct packed_short {
+	guint16 s;
+} __attribute__((packed));
+
+struct packed_long {
+	guint32 l;
+} __attribute__((packed));
+
+static inline guint32 __get_unaligned_long(const gpointer p)
+{
+	const struct packed_long *ptr = p;
+	return ptr->l;
+}
+
+static inline guint16 __get_unaligned_short(const gpointer p)
+{
+	const struct packed_short *ptr = p;
+	return ptr->s;
+}
+
+#define get_host_long(p) \
+	(ntohl(__get_unaligned_long(p)))
+
+#define get_host_short(p) \
+	(ntohs(__get_unaligned_short(p)))
+
+#define ppp_info(packet) \
+	(packet + 4)
+
+#define ppp_proto(packet) \
+	(get_host_short(packet + 2))
+
+struct _GAtPPP {
+	gint ref_count;
+	enum ppp_phase phase;
+	guint8 buffer[BUFFERSZ];
+	int index;
+	gint mru;
+	guint16 auth_proto;
+	char user_name[256];
+	char passwd[256];
+	gboolean pfc;
+	gboolean acfc;
+	guint32 xmit_accm[8];
+	guint32 recv_accm;
+	GIOChannel *modem;
+	GQueue *event_queue;
+	GQueue *recv_queue;
+	GAtPPPConnectFunc connect_cb;
+	gpointer connect_data;
+	GAtPPPDisconnectFunc disconnect_cb;
+	gpointer disconnect_data;
+	gint modem_watch;
+};
+
+gboolean ppp_cb(GIOChannel *channel, GIOCondition cond, gpointer data);
+void ppp_close(GAtPPP *ppp);
+void ppp_generate_event(GAtPPP *ppp, enum ppp_event event);
+void ppp_register_packet_handler(struct ppp_packet_handler *handler);
+void ppp_transmit(GAtPPP *ppp, guint8 *packet, guint infolen);
+void ppp_set_auth(GAtPPP *ppp, guint8 *auth_data);
+void ppp_set_recv_accm(GAtPPP *ppp, guint32 accm);
+guint32 ppp_get_xmit_accm(GAtPPP *ppp);
+void ppp_set_pfc(GAtPPP *ppp, gboolean pfc);
+gboolean ppp_get_pfc(GAtPPP *ppp);
+void ppp_set_acfc(GAtPPP *ppp, gboolean acfc);
+gboolean ppp_get_acfc(GAtPPP *ppp);
-- 
1.6.6.1