Merge branch 'add-rmnet-driver'

Subash Abhinov Kasiviswanathan says:

====================
net: Add support for rmnet driver

This patch series adds support for the rmnet driver which is required to
support recent chipsets using Qualcomm Technologies, Inc. modems. The data
from hardware follows the multiplexing and aggregation protocol (MAP).

This driver can be used to register onto any physical network device in
IP mode. Physical transports include USB, HSIC, PCIe and IP accelerator.

rmnet driver helps to decode these packets and queue them to network
stack (and encode and transmit it to the physical device).

v1: Same as the RFC patch with some minor fixes for issues reported by
kbuild test robot.

v1->v2: Change datatypes and remove config IOCTL as mentioned by David.
Also fix checkpatch issues and remove some unused code.

v2->v3: Move location to drivers/net and rename to rmnet. Change the
userspace - netlink communication from custom netlink to rtnl_link_ops.
Refactor some code. Use a fixed config for ingress and egress.

v3->v4: Move location to drivers/net/ethernet/qualcomm/.
Fix comments from Stephen and Jiri -
Split the ether and arp type changes into seperate patches.
Remove debug and custom logging and switch to standard netdevice log.
Remove module parameters. Refactor and change some code style issues.

v4->v5: Rename some structs and variables. Move the initializer
before the for loop start. Put the arp type in correct sequence.

v5->v6: Fix comments from Dan -
Use the upper link API. As a result, remove all the refcounting logic.
Device refcount is explicitly held on real_dev on rx_handler
registration only. Modifiy the flow control struct. Remove the unused
ethernet mode handling.

v6->v7: Fix comments from David - Add newline to end of Makefile. Remove
inline from .c files. Move the module init/exit to rmnet config. Fix an
error reported by kbuild test robot for an unused file.

v7->v8: Use a smaller value for ETH_P_MAP as mentioned by David. Change
netdev_info to netdev_dbg as mentioned by Andew. Fix comments from
Stephen regarding netdev_priv and sparse related errors of using 0 as NULL

v8->v9: Fix comments from David - Remove the CFLAG rule. Change the way
rmnet devices are freed. Instead of using a workqueue to unregister devices
individually, go through the list and free all devices within the rtnl_lock().

v9->v10: Actually fix the locking as mentioned by David. The locking scheme is
mentioned in a comment in rmnet_config.c. Change comment near MAP type
definition as mentioned by Dan. Refactor some code.

v10->v11: Allow RMNET to compile as a module as mentioned by David
====================
Signed-off-by: David S. Miller <davem@davemloft.net>

Documentation/networking/rmnet.txt

+1. Introduction
+
+rmnet driver is used for supporting the Multiplexing and aggregation
+Protocol (MAP). This protocol is used by all recent chipsets using Qualcomm
+Technologies, Inc. modems.
+
+This driver can be used to register onto any physical network device in
+IP mode. Physical transports include USB, HSIC, PCIe and IP accelerator.
+
+Multiplexing allows for creation of logical netdevices (rmnet devices) to
+handle multiple private data networks (PDN) like a default internet, tethering,
+multimedia messaging service (MMS) or IP media subsystem (IMS). Hardware sends
+packets with MAP headers to rmnet. Based on the multiplexer id, rmnet
+routes to the appropriate PDN after removing the MAP header.
+
+Aggregation is required to achieve high data rates. This involves hardware
+sending aggregated bunch of MAP frames. rmnet driver will de-aggregate
+these MAP frames and send them to appropriate PDN's.
+
+2. Packet format
+
+a. MAP packet (data / control)
+
+MAP header has the same endianness of the IP packet.
+
+Packet format -
+
+Bit             0             1           2-7      8 - 15           16 - 31
+Function   Command / Data   Reserved     Pad   Multiplexer ID    Payload length
+Bit            32 - x
+Function     Raw  Bytes
+
+Command (1)/ Data (0) bit value is to indicate if the packet is a MAP command
+or data packet. Control packet is used for transport level flow control. Data
+packets are standard IP packets.
+
+Reserved bits are usually zeroed out and to be ignored by receiver.
+
+Padding is number of bytes to be added for 4 byte alignment if required by
+hardware.
+
+Multiplexer ID is to indicate the PDN on which data has to be sent.
+
+Payload length includes the padding length but does not include MAP header
+length.
+
+b. MAP packet (command specific)
+
+Bit             0             1           2-7      8 - 15           16 - 31
+Function   Command         Reserved     Pad   Multiplexer ID    Payload length
+Bit          32 - 39        40 - 45    46 - 47       48 - 63
+Function   Command name    Reserved   Command Type   Reserved
+Bit          64 - 95
+Function   Transaction ID
+Bit          96 - 127
+Function   Command data
+
+Command 1 indicates disabling flow while 2 is enabling flow
+
+Command types -
+0 for MAP command request
+1 is to acknowledge the receipt of a command
+2 is for unsupported commands
+3 is for error during processing of commands
+
+c. Aggregation
+
+Aggregation is multiple MAP packets (can be data or command) delivered to
+rmnet in a single linear skb. rmnet will process the individual
+packets and either ACK the MAP command or deliver the IP packet to the
+network stack as needed
+
+MAP header|IP Packet|Optional padding|MAP header|IP Packet|Optional padding....
+MAP header|IP Packet|Optional padding|MAP header|Command Packet|Optional pad...
+
+3. Userspace configuration
+
+rmnet userspace configuration is done through netlink library librmnetctl
+and command line utility rmnetcli. Utility is hosted in codeaurora forum git.
+The driver uses rtnl_link_ops for communication.
+
+https://source.codeaurora.org/quic/la/platform/vendor/qcom-opensource/dataservices/tree/rmnetctl

drivers/net/ethernet/qualcomm/Kconfig

@@ -59,4 +59,6 @@ config QCOM_EMAC
 	  low power, Receive-Side Scaling (RSS), and IEEE 1588-2008
 	  Precision Clock Synchronization Protocol.
 
+source "drivers/net/ethernet/qualcomm/rmnet/Kconfig"
+
 endif # NET_VENDOR_QUALCOMM

drivers/net/ethernet/qualcomm/Makefile

@@ -9,3 +9,5 @@ obj-$(CONFIG_QCA7000_UART) += qcauart.o
 qcauart-objs := qca_uart.o
 
 obj-y += emac/
+
+obj-$(CONFIG_RMNET) += rmnet/

drivers/net/ethernet/qualcomm/rmnet/Kconfig

+#
+# RMNET MAP driver
+#
+
+menuconfig RMNET
+	tristate "RmNet MAP driver"
+	default n
+	---help---
+	  If you select this, you will enable the RMNET module which is used
+	  for handling data in the multiplexing and aggregation protocol (MAP)
+	  format in the embedded data path. RMNET devices can be attached to
+	  any IP mode physical device.

drivers/net/ethernet/qualcomm/rmnet/Makefile

+#
+# Makefile for the RMNET module
+#
+
+rmnet-y		 := rmnet_config.o
+rmnet-y		 += rmnet_vnd.o
+rmnet-y		 += rmnet_handlers.o
+rmnet-y		 += rmnet_map_data.o
+rmnet-y		 += rmnet_map_command.o
+obj-$(CONFIG_RMNET) += rmnet.o

drivers/net/ethernet/qualcomm/rmnet/rmnet_config.c

+/* Copyright (c) 2013-2017, The Linux Foundation. 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 and
+ * only 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.
+ *
+ * RMNET configuration engine
+ *
+ */
+
+#include <net/sock.h>
+#include <linux/module.h>
+#include <linux/netlink.h>
+#include <linux/netdevice.h>
+#include "rmnet_config.h"
+#include "rmnet_handlers.h"
+#include "rmnet_vnd.h"
+#include "rmnet_private.h"
+
+/* Locking scheme -
+ * The shared resource which needs to be protected is realdev->rx_handler_data.
+ * For the writer path, this is using rtnl_lock(). The writer paths are
+ * rmnet_newlink(), rmnet_dellink() and rmnet_force_unassociate_device(). These
+ * paths are already called with rtnl_lock() acquired in. There is also an
+ * ASSERT_RTNL() to ensure that we are calling with rtnl acquired. For
+ * dereference here, we will need to use rtnl_dereference(). Dev list writing
+ * needs to happen with rtnl_lock() acquired for netdev_master_upper_dev_link().
+ * For the reader path, the real_dev->rx_handler_data is called in the TX / RX
+ * path. We only need rcu_read_lock() for these scenarios. In these cases,
+ * the rcu_read_lock() is held in __dev_queue_xmit() and
+ * netif_receive_skb_internal(), so readers need to use rcu_dereference_rtnl()
+ * to get the relevant information. For dev list reading, we again acquire
+ * rcu_read_lock() in rmnet_dellink() for netdev_master_upper_dev_get_rcu().
+ * We also use unregister_netdevice_many() to free all rmnet devices in
+ * rmnet_force_unassociate_device() so we dont lose the rtnl_lock() and free in
+ * same context.
+ */
+
+/* Local Definitions and Declarations */
+#define RMNET_LOCAL_LOGICAL_ENDPOINT -1
+
+struct rmnet_walk_data {
+	struct net_device *real_dev;
+	struct list_head *head;
+	struct rmnet_real_dev_info *real_dev_info;
+};
+
+static int rmnet_is_real_dev_registered(const struct net_device *real_dev)
+{
+	rx_handler_func_t *rx_handler;
+
+	rx_handler = rcu_dereference(real_dev->rx_handler);
+	return (rx_handler == rmnet_rx_handler);
+}
+
+/* Needs either rcu_read_lock() or rtnl lock */
+static struct rmnet_real_dev_info*
+__rmnet_get_real_dev_info(const struct net_device *real_dev)
+{
+	if (rmnet_is_real_dev_registered(real_dev))
+		return rcu_dereference_rtnl(real_dev->rx_handler_data);
+	else
+		return NULL;
+}
+
+/* Needs rtnl lock */
+static struct rmnet_real_dev_info*
+rmnet_get_real_dev_info_rtnl(const struct net_device *real_dev)
+{
+	return rtnl_dereference(real_dev->rx_handler_data);
+}
+
+static struct rmnet_endpoint*
+rmnet_get_endpoint(struct net_device *dev, int config_id)
+{
+	struct rmnet_real_dev_info *r;
+	struct rmnet_endpoint *ep;
+
+	if (!rmnet_is_real_dev_registered(dev)) {
+		ep = rmnet_vnd_get_endpoint(dev);
+	} else {
+		r = __rmnet_get_real_dev_info(dev);
+
+		if (!r)
+			return NULL;
+
+		if (config_id == RMNET_LOCAL_LOGICAL_ENDPOINT)
+			ep = &r->local_ep;
+		else
+			ep = &r->muxed_ep[config_id];
+	}
+
+	return ep;
+}
+
+static int rmnet_unregister_real_device(struct net_device *real_dev,
+					struct rmnet_real_dev_info *r)
+{
+	if (r->nr_rmnet_devs)
+		return -EINVAL;
+
+	kfree(r);
+
+	netdev_rx_handler_unregister(real_dev);
+
+	/* release reference on real_dev */
+	dev_put(real_dev);
+
+	netdev_dbg(real_dev, "Removed from rmnet\n");
+	return 0;
+}
+
+static int rmnet_register_real_device(struct net_device *real_dev)
+{
+	struct rmnet_real_dev_info *r;
+	int rc;
+
+	ASSERT_RTNL();
+
+	if (rmnet_is_real_dev_registered(real_dev))
+		return 0;
+
+	r = kzalloc(sizeof(*r), GFP_ATOMIC);
+	if (!r)
+		return -ENOMEM;
+
+	r->dev = real_dev;
+	rc = netdev_rx_handler_register(real_dev, rmnet_rx_handler, r);
+	if (rc) {
+		kfree(r);
+		return -EBUSY;
+	}
+
+	/* hold on to real dev for MAP data */
+	dev_hold(real_dev);
+
+	netdev_dbg(real_dev, "registered with rmnet\n");
+	return 0;
+}
+
+static int rmnet_set_ingress_data_format(struct net_device *dev, u32 idf)
+{
+	struct rmnet_real_dev_info *r;
+
+	netdev_dbg(dev, "Ingress format 0x%08X\n", idf);
+
+	r = __rmnet_get_real_dev_info(dev);
+
+	r->ingress_data_format = idf;
+
+	return 0;
+}
+
+static int rmnet_set_egress_data_format(struct net_device *dev, u32 edf,
+					u16 agg_size, u16 agg_count)
+{
+	struct rmnet_real_dev_info *r;
+
+	netdev_dbg(dev, "Egress format 0x%08X agg size %d cnt %d\n",
+		   edf, agg_size, agg_count);
+
+	r = __rmnet_get_real_dev_info(dev);
+
+	r->egress_data_format = edf;
+
+	return 0;
+}
+
+static int __rmnet_set_endpoint_config(struct net_device *dev, int config_id,
+				       struct rmnet_endpoint *ep)
+{
+	struct rmnet_endpoint *dev_ep;
+
+	dev_ep = rmnet_get_endpoint(dev, config_id);
+
+	if (!dev_ep)
+		return -EINVAL;
+
+	memcpy(dev_ep, ep, sizeof(struct rmnet_endpoint));
+	if (config_id == RMNET_LOCAL_LOGICAL_ENDPOINT)
+		dev_ep->mux_id = 0;
+	else
+		dev_ep->mux_id = config_id;
+
+	return 0;
+}
+
+static int rmnet_set_endpoint_config(struct net_device *dev,
+				     int config_id, u8 rmnet_mode,
+				     struct net_device *egress_dev)
+{
+	struct rmnet_endpoint ep;
+
+	netdev_dbg(dev, "id %d mode %d dev %s\n",
+		   config_id, rmnet_mode, egress_dev->name);
+
+	if (config_id < RMNET_LOCAL_LOGICAL_ENDPOINT ||
+	    config_id >= RMNET_MAX_LOGICAL_EP)
+		return -EINVAL;
+
+	/* This config is cleared on every set, so its ok to not
+	 * clear it on a device delete.
+	 */
+	memset(&ep, 0, sizeof(struct rmnet_endpoint));
+	ep.rmnet_mode = rmnet_mode;
+	ep.egress_dev = egress_dev;
+
+	return __rmnet_set_endpoint_config(dev, config_id, &ep);
+}
+
+static int rmnet_newlink(struct net *src_net, struct net_device *dev,
+			 struct nlattr *tb[], struct nlattr *data[],
+			 struct netlink_ext_ack *extack)
+{
+	int ingress_format = RMNET_INGRESS_FORMAT_DEMUXING |
+			     RMNET_INGRESS_FORMAT_DEAGGREGATION |
+			     RMNET_INGRESS_FORMAT_MAP;
+	int egress_format = RMNET_EGRESS_FORMAT_MUXING |
+			    RMNET_EGRESS_FORMAT_MAP;
+	struct rmnet_real_dev_info *r;
+	struct net_device *real_dev;
+	int mode = RMNET_EPMODE_VND;
+	int err = 0;
+	u16 mux_id;
+
+	real_dev = __dev_get_by_index(src_net, nla_get_u32(tb[IFLA_LINK]));
+	if (!real_dev || !dev)
+		return -ENODEV;
+
+	if (!data[IFLA_VLAN_ID])
+		return -EINVAL;
+
+	mux_id = nla_get_u16(data[IFLA_VLAN_ID]);
+
+	err = rmnet_register_real_device(real_dev);
+	if (err)
+		goto err0;
+
+	r = rmnet_get_real_dev_info_rtnl(real_dev);
+	err = rmnet_vnd_newlink(mux_id, dev, r);
+	if (err)
+		goto err1;
+
+	err = netdev_master_upper_dev_link(dev, real_dev, NULL, NULL);
+	if (err)
+		goto err2;
+
+	rmnet_vnd_set_mux(dev, mux_id);
+	rmnet_set_egress_data_format(real_dev, egress_format, 0, 0);
+	rmnet_set_ingress_data_format(real_dev, ingress_format);
+	rmnet_set_endpoint_config(real_dev, mux_id, mode, dev);
+	rmnet_set_endpoint_config(dev, mux_id, mode, real_dev);
+	return 0;
+
+err2:
+	rmnet_vnd_dellink(mux_id, r);
+err1:
+	rmnet_unregister_real_device(real_dev, r);
+err0:
+	return err;
+}
+
+static void rmnet_dellink(struct net_device *dev, struct list_head *head)
+{
+	struct rmnet_real_dev_info *r;
+	struct net_device *real_dev;
+	u8 mux_id;
+
+	rcu_read_lock();
+	real_dev = netdev_master_upper_dev_get_rcu(dev);
+	rcu_read_unlock();
+
+	if (!real_dev || !rmnet_is_real_dev_registered(real_dev))
+		return;
+
+	r = rmnet_get_real_dev_info_rtnl(real_dev);
+
+	mux_id = rmnet_vnd_get_mux(dev);
+	rmnet_vnd_dellink(mux_id, r);
+	netdev_upper_dev_unlink(dev, real_dev);
+	rmnet_unregister_real_device(real_dev, r);
+
+	unregister_netdevice_queue(dev, head);
+}
+
+static int rmnet_dev_walk_unreg(struct net_device *rmnet_dev, void *data)
+{
+	struct rmnet_walk_data *d = data;
+	u8 mux_id;
+
+	mux_id = rmnet_vnd_get_mux(rmnet_dev);
+
+	rmnet_vnd_dellink(mux_id, d->real_dev_info);
+	netdev_upper_dev_unlink(rmnet_dev, d->real_dev);
+	unregister_netdevice_queue(rmnet_dev, d->head);
+
+	return 0;
+}
+
+static void rmnet_force_unassociate_device(struct net_device *dev)
+{
+	struct net_device *real_dev = dev;
+	struct rmnet_real_dev_info *r;
+	struct rmnet_walk_data d;
+	LIST_HEAD(list);
+
+	if (!rmnet_is_real_dev_registered(real_dev))
+		return;
+
+	ASSERT_RTNL();
+
+	d.real_dev = real_dev;
+	d.head = &list;
+
+	r = rmnet_get_real_dev_info_rtnl(dev);
+	d.real_dev_info = r;
+
+	rcu_read_lock();
+	netdev_walk_all_lower_dev_rcu(real_dev, rmnet_dev_walk_unreg, &d);
+	rcu_read_unlock();
+	unregister_netdevice_many(&list);
+
+	rmnet_unregister_real_device(real_dev, r);
+}
+
+static int rmnet_config_notify_cb(struct notifier_block *nb,
+				  unsigned long event, void *data)
+{
+	struct net_device *dev = netdev_notifier_info_to_dev(data);
+
+	if (!dev)
+		return NOTIFY_DONE;
+
+	switch (event) {
+	case NETDEV_UNREGISTER:
+		netdev_dbg(dev, "Kernel unregister\n");
+		rmnet_force_unassociate_device(dev);
+		break;
+
+	default:
+		break;
+	}
+
+	return NOTIFY_DONE;
+}
+
+static struct notifier_block rmnet_dev_notifier __read_mostly = {
+	.notifier_call = rmnet_config_notify_cb,
+};
+
+static int rmnet_rtnl_validate(struct nlattr *tb[], struct nlattr *data[],
+			       struct netlink_ext_ack *extack)
+{
+	u16 mux_id;
+
+	if (!data || !data[IFLA_VLAN_ID])
+		return -EINVAL;
+
+	mux_id = nla_get_u16(data[IFLA_VLAN_ID]);
+	if (mux_id > (RMNET_MAX_LOGICAL_EP - 1))
+		return -ERANGE;
+
+	return 0;
+}
+
+static size_t rmnet_get_size(const struct net_device *dev)
+{
+	return nla_total_size(2); /* IFLA_VLAN_ID */
+}
+
+struct rtnl_link_ops rmnet_link_ops __read_mostly = {
+	.kind		= "rmnet",
+	.maxtype	= __IFLA_VLAN_MAX,
+	.priv_size	= sizeof(struct rmnet_priv),
+	.setup		= rmnet_vnd_setup,
+	.validate	= rmnet_rtnl_validate,
+	.newlink	= rmnet_newlink,
+	.dellink	= rmnet_dellink,
+	.get_size	= rmnet_get_size,
+};
+
+struct rmnet_real_dev_info*
+rmnet_get_real_dev_info(struct net_device *real_dev)
+{
+	return __rmnet_get_real_dev_info(real_dev);
+}
+
+/* Startup/Shutdown */
+
+static int __init rmnet_init(void)
+{
+	int rc;
+
+	rc = register_netdevice_notifier(&rmnet_dev_notifier);
+	if (rc != 0)
+		return rc;
+
+	rc = rtnl_link_register(&rmnet_link_ops);
+	if (rc != 0) {
+		unregister_netdevice_notifier(&rmnet_dev_notifier);
+		return rc;
+	}
+	return rc;
+}
+
+static void __exit rmnet_exit(void)
+{
+	unregister_netdevice_notifier(&rmnet_dev_notifier);
+	rtnl_link_unregister(&rmnet_link_ops);
+}
+
+module_init(rmnet_init)
+module_exit(rmnet_exit)
+MODULE_LICENSE("GPL v2");

drivers/net/ethernet/qualcomm/rmnet/rmnet_config.h

+/* Copyright (c) 2013-2014, 2016-2017 The Linux Foundation. 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 and
+ * only 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.
+ *
+ * RMNET Data configuration engine
+ *
+ */
+
+#include <linux/skbuff.h>
+
+#ifndef _RMNET_CONFIG_H_
+#define _RMNET_CONFIG_H_
+
+#define RMNET_MAX_LOGICAL_EP 255
+#define RMNET_MAX_VND        32
+
+/* Information about the next device to deliver the packet to.
+ * Exact usage of this parameter depends on the rmnet_mode.
+ */
+struct rmnet_endpoint {
+	u8 rmnet_mode;
+	u8 mux_id;
+	struct net_device *egress_dev;
+};
+
+/* One instance of this structure is instantiated for each real_dev associated
+ * with rmnet.
+ */
+struct rmnet_real_dev_info {
+	struct net_device *dev;
+	struct rmnet_endpoint local_ep;
+	struct rmnet_endpoint muxed_ep[RMNET_MAX_LOGICAL_EP];
+	u32 ingress_data_format;
+	u32 egress_data_format;
+	struct net_device *rmnet_devices[RMNET_MAX_VND];
+	u8 nr_rmnet_devs;
+};
+
+extern struct rtnl_link_ops rmnet_link_ops;
+
+struct rmnet_priv {
+	struct rmnet_endpoint local_ep;
+	u8 mux_id;
+};
+
+struct rmnet_real_dev_info*
+rmnet_get_real_dev_info(struct net_device *real_dev);
+
+#endif /* _RMNET_CONFIG_H_ */

drivers/net/ethernet/qualcomm/rmnet/rmnet_handlers.c

+/* Copyright (c) 2013-2017, The Linux Foundation. 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 and
+ * only 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.
+ *
+ * RMNET Data ingress/egress handler
+ *
+ */
+
+#include <linux/netdevice.h>
+#include <linux/netdev_features.h>
+#include "rmnet_private.h"
+#include "rmnet_config.h"
+#include "rmnet_vnd.h"
+#include "rmnet_map.h"
+#include "rmnet_handlers.h"
+
+#define RMNET_IP_VERSION_4 0x40
+#define RMNET_IP_VERSION_6 0x60
+
+/* Helper Functions */
+
+static void rmnet_set_skb_proto(struct sk_buff *skb)
+{
+	switch (skb->data[0] & 0xF0) {
+	case RMNET_IP_VERSION_4:
+		skb->protocol = htons(ETH_P_IP);
+		break;
+	case RMNET_IP_VERSION_6:
+		skb->protocol = htons(ETH_P_IPV6);
+		break;
+	default:
+		skb->protocol = htons(ETH_P_MAP);
+		break;
+	}
+}
+
+/* Generic handler */
+
+static rx_handler_result_t
+rmnet_bridge_handler(struct sk_buff *skb, struct rmnet_endpoint *ep)
+{
+	if (!ep->egress_dev)
+		kfree_skb(skb);
+	else
+		rmnet_egress_handler(skb, ep);
+
+	return RX_HANDLER_CONSUMED;
+}
+
+static rx_handler_result_t
+rmnet_deliver_skb(struct sk_buff *skb, struct rmnet_endpoint *ep)
+{
+	switch (ep->rmnet_mode) {
+	case RMNET_EPMODE_NONE:
+		return RX_HANDLER_PASS;
+
+	case RMNET_EPMODE_BRIDGE:
+		return rmnet_bridge_handler(skb, ep);
+
+	case RMNET_EPMODE_VND:
+		skb_reset_transport_header(skb);
+		skb_reset_network_header(skb);
+		rmnet_vnd_rx_fixup(skb, skb->dev);
+
+		skb->pkt_type = PACKET_HOST;
+		skb_set_mac_header(skb, 0);
+		netif_receive_skb(skb);
+		return RX_HANDLER_CONSUMED;
+
+	default:
+		kfree_skb(skb);
+		return RX_HANDLER_CONSUMED;
+	}
+}
+
+static rx_handler_result_t
+rmnet_ingress_deliver_packet(struct sk_buff *skb,
+			     struct rmnet_real_dev_info *r)
+{
+	if (!r) {
+		kfree_skb(skb);
+		return RX_HANDLER_CONSUMED;
+	}
+
+	skb->dev = r->local_ep.egress_dev;
+
+	return rmnet_deliver_skb(skb, &r->local_ep);
+}
+
+/* MAP handler */
+
+static rx_handler_result_t
+__rmnet_map_ingress_handler(struct sk_buff *skb,
+			    struct rmnet_real_dev_info *r)
+{
+	struct rmnet_endpoint *ep;
+	u8 mux_id;
+	u16 len;
+
+	if (RMNET_MAP_GET_CD_BIT(skb)) {
+		if (r->ingress_data_format
+		    & RMNET_INGRESS_FORMAT_MAP_COMMANDS)
+			return rmnet_map_command(skb, r);
+
+		kfree_skb(skb);
+		return RX_HANDLER_CONSUMED;
+	}
+
+	mux_id = RMNET_MAP_GET_MUX_ID(skb);
+	len = RMNET_MAP_GET_LENGTH(skb) - RMNET_MAP_GET_PAD(skb);
+
+	if (mux_id >= RMNET_MAX_LOGICAL_EP) {
+		kfree_skb(skb);
+		return RX_HANDLER_CONSUMED;
+	}
+
+	ep = &r->muxed_ep[mux_id];
+
+	if (r->ingress_data_format & RMNET_INGRESS_FORMAT_DEMUXING)
+		skb->dev = ep->egress_dev;
+
+	/* Subtract MAP header */
+	skb_pull(skb, sizeof(struct rmnet_map_header));
+	skb_trim(skb, len);
+	rmnet_set_skb_proto(skb);
+	return rmnet_deliver_skb(skb, ep);
+}
+
+static rx_handler_result_t
+rmnet_map_ingress_handler(struct sk_buff *skb,
+			  struct rmnet_real_dev_info *r)
+{
+	struct sk_buff *skbn;
+	int rc;
+
+	if (r->ingress_data_format & RMNET_INGRESS_FORMAT_DEAGGREGATION) {
+		while ((skbn = rmnet_map_deaggregate(skb, r)) != NULL)
+			__rmnet_map_ingress_handler(skbn, r);
+
+		consume_skb(skb);
+		rc = RX_HANDLER_CONSUMED;
+	} else {
+		rc = __rmnet_map_ingress_handler(skb, r);
+	}
+
+	return rc;
+}
+
+static int rmnet_map_egress_handler(struct sk_buff *skb,
+				    struct rmnet_real_dev_info *r,
+				    struct rmnet_endpoint *ep,
+				    struct net_device *orig_dev)
+{
+	int required_headroom, additional_header_len;
+	struct rmnet_map_header *map_header;
+
+	additional_header_len = 0;
+	required_headroom = sizeof(struct rmnet_map_header);
+
+	if (skb_headroom(skb) < required_headroom) {
+		if (pskb_expand_head(skb, required_headroom, 0, GFP_KERNEL))
+			return RMNET_MAP_CONSUMED;
+	}
+
+	map_header = rmnet_map_add_map_header(skb, additional_header_len, 0);
+	if (!map_header)
+		return RMNET_MAP_CONSUMED;
+
+	if (r->egress_data_format & RMNET_EGRESS_FORMAT_MUXING) {
+		if (ep->mux_id == 0xff)
+			map_header->mux_id = 0;
+		else
+			map_header->mux_id = ep->mux_id;
+	}
+
+	skb->protocol = htons(ETH_P_MAP);
+
+	return RMNET_MAP_SUCCESS;
+}
+
+/* Ingress / Egress Entry Points */
+
+/* Processes packet as per ingress data format for receiving device. Logical
+ * endpoint is determined from packet inspection. Packet is then sent to the
+ * egress device listed in the logical endpoint configuration.
+ */
+rx_handler_result_t rmnet_rx_handler(struct sk_buff **pskb)
+{
+	struct rmnet_real_dev_info *r;
+	struct sk_buff *skb = *pskb;
+	struct net_device *dev;
+	int rc;
+
+	if (!skb)
+		return RX_HANDLER_CONSUMED;
+
+	dev = skb->dev;
+	r = rmnet_get_real_dev_info(dev);
+
+	if (r->ingress_data_format & RMNET_INGRESS_FORMAT_MAP) {
+		rc = rmnet_map_ingress_handler(skb, r);
+	} else {
+		switch (ntohs(skb->protocol)) {
+		case ETH_P_MAP:
+			if (r->local_ep.rmnet_mode ==
+				RMNET_EPMODE_BRIDGE) {
+				rc = rmnet_ingress_deliver_packet(skb, r);
+			} else {
+				kfree_skb(skb);
+				rc = RX_HANDLER_CONSUMED;
+			}
+			break;
+
+		case ETH_P_IP:
+		case ETH_P_IPV6:
+			rc = rmnet_ingress_deliver_packet(skb, r);
+			break;
+
+		default:
+			rc = RX_HANDLER_PASS;
+		}
+	}
+
+	return rc;
+}
+
+/* Modifies packet as per logical endpoint configuration and egress data format
+ * for egress device configured in logical endpoint. Packet is then transmitted
+ * on the egress device.
+ */
+void rmnet_egress_handler(struct sk_buff *skb,
+			  struct rmnet_endpoint *ep)
+{
+	struct rmnet_real_dev_info *r;
+	struct net_device *orig_dev;
+
+	orig_dev = skb->dev;
+	skb->dev = ep->egress_dev;
+
+	r = rmnet_get_real_dev_info(skb->dev);
+	if (!r) {
+		kfree_skb(skb);
+		return;
+	}
+
+	if (r->egress_data_format & RMNET_EGRESS_FORMAT_MAP) {
+		switch (rmnet_map_egress_handler(skb, r, ep, orig_dev)) {
+		case RMNET_MAP_CONSUMED:
+			return;
+
+		case RMNET_MAP_SUCCESS:
+			break;
+
+		default:
+			kfree_skb(skb);
+			return;
+		}
+	}
+
+	if (ep->rmnet_mode == RMNET_EPMODE_VND)
+		rmnet_vnd_tx_fixup(skb, orig_dev);
+
+	dev_queue_xmit(skb);
+}

drivers/net/ethernet/qualcomm/rmnet/rmnet_handlers.h

+/* Copyright (c) 2013, 2016-2017 The Linux Foundation. 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 and
+ * only 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.
+ *
+ * RMNET Data ingress/egress handler
+ *
+ */
+
+#ifndef _RMNET_HANDLERS_H_
+#define _RMNET_HANDLERS_H_
+
+#include "rmnet_config.h"
+
+void rmnet_egress_handler(struct sk_buff *skb,
+			  struct rmnet_endpoint *ep);
+
+rx_handler_result_t rmnet_rx_handler(struct sk_buff **pskb);
+
+#endif /* _RMNET_HANDLERS_H_ */

drivers/net/ethernet/qualcomm/rmnet/rmnet_map.h

+/* Copyright (c) 2013-2017, The Linux Foundation. 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 and
+ * only 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.
+ */
+
+#ifndef _RMNET_MAP_H_
+#define _RMNET_MAP_H_
+
+struct rmnet_map_control_command {
+	u8  command_name;
+	u8  cmd_type:2;
+	u8  reserved:6;
+	u16 reserved2;
+	u32 transaction_id;
+	union {
+		struct {
+			u16 ip_family:2;
+			u16 reserved:14;
+			u16 flow_control_seq_num;
+			u32 qos_id;
+		} flow_control;
+		u8 data[0];
+	};
+}  __aligned(1);
+
+enum rmnet_map_results {
+	RMNET_MAP_SUCCESS,
+	RMNET_MAP_CONSUMED,
+	RMNET_MAP_GENERAL_FAILURE,
+	RMNET_MAP_NOT_ENABLED,
+	RMNET_MAP_FAILED_AGGREGATION,
+	RMNET_MAP_FAILED_MUX
+};
+
+enum rmnet_map_commands {
+	RMNET_MAP_COMMAND_NONE,
+	RMNET_MAP_COMMAND_FLOW_DISABLE,
+	RMNET_MAP_COMMAND_FLOW_ENABLE,
+	/* These should always be the last 2 elements */
+	RMNET_MAP_COMMAND_UNKNOWN,
+	RMNET_MAP_COMMAND_ENUM_LENGTH
+};
+
+struct rmnet_map_header {
+	u8  pad_len:6;
+	u8  reserved_bit:1;
+	u8  cd_bit:1;
+	u8  mux_id;
+	u16 pkt_len;
+}  __aligned(1);
+
+#define RMNET_MAP_GET_MUX_ID(Y) (((struct rmnet_map_header *) \
+				 (Y)->data)->mux_id)
+#define RMNET_MAP_GET_CD_BIT(Y) (((struct rmnet_map_header *) \
+				(Y)->data)->cd_bit)
+#define RMNET_MAP_GET_PAD(Y) (((struct rmnet_map_header *) \
+				(Y)->data)->pad_len)
+#define RMNET_MAP_GET_CMD_START(Y) ((struct rmnet_map_control_command *) \
+				    ((Y)->data + \
+				      sizeof(struct rmnet_map_header)))
+#define RMNET_MAP_GET_LENGTH(Y) (ntohs(((struct rmnet_map_header *) \
+					(Y)->data)->pkt_len))
+
+#define RMNET_MAP_COMMAND_REQUEST     0
+#define RMNET_MAP_COMMAND_ACK         1
+#define RMNET_MAP_COMMAND_UNSUPPORTED 2
+#define RMNET_MAP_COMMAND_INVALID     3
+
+#define RMNET_MAP_NO_PAD_BYTES        0
+#define RMNET_MAP_ADD_PAD_BYTES       1
+
+u8 rmnet_map_demultiplex(struct sk_buff *skb);
+struct sk_buff *rmnet_map_deaggregate(struct sk_buff *skb,
+				      struct rmnet_real_dev_info *rdinfo);
+
+struct rmnet_map_header *rmnet_map_add_map_header(struct sk_buff *skb,
+						  int hdrlen, int pad);
+rx_handler_result_t rmnet_map_command(struct sk_buff *skb,
+				      struct rmnet_real_dev_info *rdinfo);
+
+#endif /* _RMNET_MAP_H_ */

drivers/net/ethernet/qualcomm/rmnet/rmnet_map_command.c

+/* Copyright (c) 2013-2017, The Linux Foundation. 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 and
+ * only 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.
+ */
+
+#include <linux/netdevice.h>
+#include "rmnet_config.h"
+#include "rmnet_map.h"
+#include "rmnet_private.h"
+#include "rmnet_vnd.h"
+
+static u8 rmnet_map_do_flow_control(struct sk_buff *skb,
+				    struct rmnet_real_dev_info *rdinfo,
+				    int enable)
+{
+	struct rmnet_map_control_command *cmd;
+	struct rmnet_endpoint *ep;
+	struct net_device *vnd;
+	u16 ip_family;
+	u16 fc_seq;
+	u32 qos_id;
+	u8 mux_id;
+	int r;
+
+	mux_id = RMNET_MAP_GET_MUX_ID(skb);
+	cmd = RMNET_MAP_GET_CMD_START(skb);
+
+	if (mux_id >= RMNET_MAX_LOGICAL_EP) {
+		kfree_skb(skb);
+		return RX_HANDLER_CONSUMED;
+	}
+
+	ep = &rdinfo->muxed_ep[mux_id];
+	vnd = ep->egress_dev;
+
+	ip_family = cmd->flow_control.ip_family;
+	fc_seq = ntohs(cmd->flow_control.flow_control_seq_num);
+	qos_id = ntohl(cmd->flow_control.qos_id);
+
+	/* Ignore the ip family and pass the sequence number for both v4 and v6
+	 * sequence. User space does not support creating dedicated flows for
+	 * the 2 protocols
+	 */
+	r = rmnet_vnd_do_flow_control(vnd, enable);
+	if (r) {
+		kfree_skb(skb);
+		return RMNET_MAP_COMMAND_UNSUPPORTED;
+	} else {
+		return RMNET_MAP_COMMAND_ACK;
+	}
+}
+
+static void rmnet_map_send_ack(struct sk_buff *skb,
+			       unsigned char type,
+			       struct rmnet_real_dev_info *rdinfo)
+{
+	struct rmnet_map_control_command *cmd;
+	int xmit_status;
+
+	skb->protocol = htons(ETH_P_MAP);
+
+	cmd = RMNET_MAP_GET_CMD_START(skb);
+	cmd->cmd_type = type & 0x03;
+
+	netif_tx_lock(skb->dev);
+	xmit_status = skb->dev->netdev_ops->ndo_start_xmit(skb, skb->dev);
+	netif_tx_unlock(skb->dev);
+}
+
+/* Process MAP command frame and send N/ACK message as appropriate. Message cmd
+ * name is decoded here and appropriate handler is called.
+ */
+rx_handler_result_t rmnet_map_command(struct sk_buff *skb,
+				      struct rmnet_real_dev_info *rdinfo)
+{
+	struct rmnet_map_control_command *cmd;
+	unsigned char command_name;
+	unsigned char rc = 0;
+
+	cmd = RMNET_MAP_GET_CMD_START(skb);
+	command_name = cmd->command_name;
+
+	switch (command_name) {
+	case RMNET_MAP_COMMAND_FLOW_ENABLE:
+		rc = rmnet_map_do_flow_control(skb, rdinfo, 1);
+		break;
+
+	case RMNET_MAP_COMMAND_FLOW_DISABLE:
+		rc = rmnet_map_do_flow_control(skb, rdinfo, 0);
+		break;
+
+	default:
+		rc = RMNET_MAP_COMMAND_UNSUPPORTED;
+		kfree_skb(skb);
+		break;
+	}
+	if (rc == RMNET_MAP_COMMAND_ACK)
+		rmnet_map_send_ack(skb, rc, rdinfo);
+	return RX_HANDLER_CONSUMED;
+}

drivers/net/ethernet/qualcomm/rmnet/rmnet_map_data.c

+/* Copyright (c) 2013-2017, The Linux Foundation. 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 and
+ * only 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.
+ *
+ * RMNET Data MAP protocol
+ *
+ */
+
+#include <linux/netdevice.h>
+#include "rmnet_config.h"
+#include "rmnet_map.h"
+#include "rmnet_private.h"
+
+#define RMNET_MAP_DEAGGR_SPACING  64
+#define RMNET_MAP_DEAGGR_HEADROOM (RMNET_MAP_DEAGGR_SPACING / 2)
+
+/* Adds MAP header to front of skb->data
+ * Padding is calculated and set appropriately in MAP header. Mux ID is
+ * initialized to 0.
+ */
+struct rmnet_map_header *rmnet_map_add_map_header(struct sk_buff *skb,
+						  int hdrlen, int pad)
+{
+	struct rmnet_map_header *map_header;
+	u32 padding, map_datalen;
+	u8 *padbytes;
+
+	if (skb_headroom(skb) < sizeof(struct rmnet_map_header))
+		return NULL;
+
+	map_datalen = skb->len - hdrlen;
+	map_header = (struct rmnet_map_header *)
+			skb_push(skb, sizeof(struct rmnet_map_header));
+	memset(map_header, 0, sizeof(struct rmnet_map_header));
+
+	if (pad == RMNET_MAP_NO_PAD_BYTES) {
+		map_header->pkt_len = htons(map_datalen);
+		return map_header;
+	}
+
+	padding = ALIGN(map_datalen, 4) - map_datalen;
+
+	if (padding == 0)
+		goto done;
+
+	if (skb_tailroom(skb) < padding)
+		return NULL;
+
+	padbytes = (u8 *)skb_put(skb, padding);
+	memset(padbytes, 0, padding);
+
+done:
+	map_header->pkt_len = htons(map_datalen + padding);
+	map_header->pad_len = padding & 0x3F;
+
+	return map_header;
+}
+
+/* Deaggregates a single packet
+ * A whole new buffer is allocated for each portion of an aggregated frame.
+ * Caller should keep calling deaggregate() on the source skb until 0 is
+ * returned, indicating that there are no more packets to deaggregate. Caller
+ * is responsible for freeing the original skb.
+ */
+struct sk_buff *rmnet_map_deaggregate(struct sk_buff *skb,
+				      struct rmnet_real_dev_info *rdinfo)
+{
+	struct rmnet_map_header *maph;
+	struct sk_buff *skbn;
+	u32 packet_len;
+
+	if (skb->len == 0)
+		return NULL;
+
+	maph = (struct rmnet_map_header *)skb->data;
+	packet_len = ntohs(maph->pkt_len) + sizeof(struct rmnet_map_header);
+
+	if (((int)skb->len - (int)packet_len) < 0)
+		return NULL;
+
+	skbn = alloc_skb(packet_len + RMNET_MAP_DEAGGR_SPACING, GFP_ATOMIC);
+	if (!skbn)
+		return NULL;
+
+	skbn->dev = skb->dev;
+	skb_reserve(skbn, RMNET_MAP_DEAGGR_HEADROOM);
+	skb_put(skbn, packet_len);
+	memcpy(skbn->data, skb->data, packet_len);
+	skb_pull(skb, packet_len);
+
+	/* Some hardware can send us empty frames. Catch them */
+	if (ntohs(maph->pkt_len) == 0) {
+		kfree_skb(skb);
+		return NULL;
+	}
+
+	return skbn;
+}

drivers/net/ethernet/qualcomm/rmnet/rmnet_private.h

+/* Copyright (c) 2013-2014, 2016-2017 The Linux Foundation. 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 and
+ * only 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.
+ */
+
+#ifndef _RMNET_PRIVATE_H_
+#define _RMNET_PRIVATE_H_
+
+#define RMNET_MAX_VND              32
+#define RMNET_MAX_PACKET_SIZE      16384
+#define RMNET_DFLT_PACKET_SIZE     1500
+#define RMNET_NEEDED_HEADROOM      16
+#define RMNET_TX_QUEUE_LEN         1000
+
+/* Constants */
+#define RMNET_EGRESS_FORMAT__RESERVED__         BIT(0)
+#define RMNET_EGRESS_FORMAT_MAP                 BIT(1)
+#define RMNET_EGRESS_FORMAT_AGGREGATION         BIT(2)
+#define RMNET_EGRESS_FORMAT_MUXING              BIT(3)
+#define RMNET_EGRESS_FORMAT_MAP_CKSUMV3         BIT(4)
+#define RMNET_EGRESS_FORMAT_MAP_CKSUMV4         BIT(5)
+
+#define RMNET_INGRESS_FIX_ETHERNET              BIT(0)
+#define RMNET_INGRESS_FORMAT_MAP                BIT(1)
+#define RMNET_INGRESS_FORMAT_DEAGGREGATION      BIT(2)
+#define RMNET_INGRESS_FORMAT_DEMUXING           BIT(3)
+#define RMNET_INGRESS_FORMAT_MAP_COMMANDS       BIT(4)
+#define RMNET_INGRESS_FORMAT_MAP_CKSUMV3        BIT(5)
+#define RMNET_INGRESS_FORMAT_MAP_CKSUMV4        BIT(6)
+
+/* Pass the frame up the stack with no modifications to skb->dev */
+#define RMNET_EPMODE_NONE (0)
+/* Replace skb->dev to a virtual rmnet device and pass up the stack */
+#define RMNET_EPMODE_VND (1)
+/* Pass the frame directly to another device with dev_queue_xmit() */
+#define RMNET_EPMODE_BRIDGE (2)
+
+#endif /* _RMNET_PRIVATE_H_ */

drivers/net/ethernet/qualcomm/rmnet/rmnet_vnd.c

+/* Copyright (c) 2013-2017, The Linux Foundation. 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 and
+ * only 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.
+ *
+ *
+ * RMNET Data virtual network driver
+ *
+ */
+
+#include <linux/etherdevice.h>
+#include <linux/if_arp.h>
+#include <net/pkt_sched.h>
+#include "rmnet_config.h"
+#include "rmnet_handlers.h"
+#include "rmnet_private.h"
+#include "rmnet_map.h"
+#include "rmnet_vnd.h"
+
+/* RX/TX Fixup */
+
+void rmnet_vnd_rx_fixup(struct sk_buff *skb, struct net_device *dev)
+{
+	dev->stats.rx_packets++;
+	dev->stats.rx_bytes += skb->len;
+}
+
+void rmnet_vnd_tx_fixup(struct sk_buff *skb, struct net_device *dev)
+{
+	dev->stats.tx_packets++;
+	dev->stats.tx_bytes += skb->len;
+}
+
+/* Network Device Operations */
+
+static netdev_tx_t rmnet_vnd_start_xmit(struct sk_buff *skb,
+					struct net_device *dev)
+{
+	struct rmnet_priv *priv;
+
+	priv = netdev_priv(dev);
+	if (priv->local_ep.egress_dev) {
+		rmnet_egress_handler(skb, &priv->local_ep);
+	} else {
+		dev->stats.tx_dropped++;
+		kfree_skb(skb);
+	}
+	return NETDEV_TX_OK;
+}
+
+static int rmnet_vnd_change_mtu(struct net_device *rmnet_dev, int new_mtu)
+{
+	if (new_mtu < 0 || new_mtu > RMNET_MAX_PACKET_SIZE)
+		return -EINVAL;
+
+	rmnet_dev->mtu = new_mtu;
+	return 0;
+}
+
+static const struct net_device_ops rmnet_vnd_ops = {
+	.ndo_start_xmit = rmnet_vnd_start_xmit,
+	.ndo_change_mtu = rmnet_vnd_change_mtu,
+};
+
+/* Called by kernel whenever a new rmnet<n> device is created. Sets MTU,
+ * flags, ARP type, needed headroom, etc...
+ */
+void rmnet_vnd_setup(struct net_device *rmnet_dev)
+{
+	struct rmnet_priv *priv;
+
+	priv = netdev_priv(rmnet_dev);
+	netdev_dbg(rmnet_dev, "Setting up device %s\n", rmnet_dev->name);
+
+	rmnet_dev->netdev_ops = &rmnet_vnd_ops;
+	rmnet_dev->mtu = RMNET_DFLT_PACKET_SIZE;
+	rmnet_dev->needed_headroom = RMNET_NEEDED_HEADROOM;
+	random_ether_addr(rmnet_dev->dev_addr);
+	rmnet_dev->tx_queue_len = RMNET_TX_QUEUE_LEN;
+
+	/* Raw IP mode */
+	rmnet_dev->header_ops = NULL;  /* No header */
+	rmnet_dev->type = ARPHRD_RAWIP;
+	rmnet_dev->hard_header_len = 0;
+	rmnet_dev->flags &= ~(IFF_BROADCAST | IFF_MULTICAST);
+
+	rmnet_dev->needs_free_netdev = true;
+}
+
+/* Exposed API */
+
+int rmnet_vnd_newlink(u8 id, struct net_device *rmnet_dev,
+		      struct rmnet_real_dev_info *r)
+{
+	int rc;
+
+	if (r->rmnet_devices[id])
+		return -EINVAL;
+
+	rc = register_netdevice(rmnet_dev);
+	if (!rc) {
+		r->rmnet_devices[id] = rmnet_dev;
+		r->nr_rmnet_devs++;
+		rmnet_dev->rtnl_link_ops = &rmnet_link_ops;
+	}
+
+	return rc;
+}
+
+int rmnet_vnd_dellink(u8 id, struct rmnet_real_dev_info *r)
+{
+	if (id >= RMNET_MAX_VND || !r->rmnet_devices[id])
+		return -EINVAL;
+
+	r->rmnet_devices[id] = NULL;
+	r->nr_rmnet_devs--;
+	return 0;
+}
+
+u8 rmnet_vnd_get_mux(struct net_device *rmnet_dev)
+{
+	struct rmnet_priv *priv;
+
+	priv = netdev_priv(rmnet_dev);
+	return priv->mux_id;
+}
+
+void rmnet_vnd_set_mux(struct net_device *rmnet_dev, u8 mux_id)
+{
+	struct rmnet_priv *priv;
+
+	priv = netdev_priv(rmnet_dev);
+	priv->mux_id = mux_id;
+}
+
+/* Gets the logical endpoint configuration for a RmNet virtual network device
+ * node. Caller should confirm that devices is a RmNet VND before calling.
+ */
+struct rmnet_endpoint *rmnet_vnd_get_endpoint(struct net_device *rmnet_dev)
+{
+	struct rmnet_priv *priv;
+
+	if (!rmnet_dev)
+		return NULL;
+
+	priv = netdev_priv(rmnet_dev);
+
+	return &priv->local_ep;
+}
+
+int rmnet_vnd_do_flow_control(struct net_device *rmnet_dev, int enable)
+{
+	netdev_dbg(rmnet_dev, "Setting VND TX queue state to %d\n", enable);
+	/* Although we expect similar number of enable/disable
+	 * commands, optimize for the disable. That is more
+	 * latency sensitive than enable
+	 */
+	if (unlikely(enable))
+		netif_wake_queue(rmnet_dev);
+	else
+		netif_stop_queue(rmnet_dev);
+
+	return 0;
+}

drivers/net/ethernet/qualcomm/rmnet/rmnet_vnd.h

+/* Copyright (c) 2013-2017, The Linux Foundation. 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 and
+ * only 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.
+ *
+ * RMNET Data Virtual Network Device APIs
+ *
+ */
+
+#ifndef _RMNET_VND_H_
+#define _RMNET_VND_H_
+
+int rmnet_vnd_do_flow_control(struct net_device *dev, int enable);
+struct rmnet_endpoint *rmnet_vnd_get_endpoint(struct net_device *dev);
+int rmnet_vnd_newlink(u8 id, struct net_device *rmnet_dev,
+		      struct rmnet_real_dev_info *r);
+int rmnet_vnd_dellink(u8 id, struct rmnet_real_dev_info *r);
+void rmnet_vnd_rx_fixup(struct sk_buff *skb, struct net_device *dev);
+void rmnet_vnd_tx_fixup(struct sk_buff *skb, struct net_device *dev);
+u8 rmnet_vnd_get_mux(struct net_device *rmnet_dev);
+void rmnet_vnd_set_mux(struct net_device *rmnet_dev, u8 mux_id);
+void rmnet_vnd_setup(struct net_device *dev);
+#endif /* _RMNET_VND_H_ */

include/uapi/linux/if_arp.h

@@ -59,6 +59,7 @@
 #define ARPHRD_LAPB	516		/* LAPB				*/
 #define ARPHRD_DDCMP    517		/* Digital's DDCMP protocol     */
 #define ARPHRD_RAWHDLC	518		/* Raw HDLC			*/
+#define ARPHRD_RAWIP    519		/* Raw IP                       */
 
 #define ARPHRD_TUNNEL	768		/* IPIP tunnel			*/
 #define ARPHRD_TUNNEL6	769		/* IP6IP6 tunnel       		*/

include/uapi/linux/if_ether.h

@@ -140,6 +140,9 @@
 #define ETH_P_IEEE802154 0x00F6		/* IEEE802.15.4 frame		*/
 #define ETH_P_CAIF	0x00F7		/* ST-Ericsson CAIF protocol	*/
 #define ETH_P_XDSA	0x00F8		/* Multiplexed DSA protocol	*/
+#define ETH_P_MAP	0x00F9		/* Qualcomm multiplexing and
+					 * aggregation protocol
+					 */
 
 /*
  *	This is an Ethernet frame header.