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From:   Jian-Hong Pan <starnight@g.ncu.edu.tw>
To:     =?UTF-8?q?Andreas=20F=C3=A4rber?= <afaerber@suse.de>
Cc:     netdev@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
        linux-kernel@vger.kernel.org,
        Marcel Holtmann <marcel@holtmann.org>,
        "David S . Miller" <davem@davemloft.net>,
        Dollar Chen <dollar.chen@wtmec.com>,
        Ken Yu <ken.yu@rakwireless.com>, linux-wpan@vger.kernel.org,
        Stefan Schmidt <stefan@datenfreihafen.org>,
        Jian-Hong Pan <starnight@g.ncu.edu.tw>
Subject: [PATCH V2 2/7] net: lorawan: Add LoRaWAN socket module
Date:   Tue,  6 Nov 2018 00:55:40 +0800
Message-Id: <20181105165544.5215-3-starnight@g.ncu.edu.tw>
In-Reply-To: <fc737f3940bbe91341fb15d85ac11931eb56d1fc.1535039998.git.starnight@g.ncu.edu.tw>
References: <fc737f3940bbe91341fb15d85ac11931eb56d1fc.1535039998.git.starnight@g.ncu.edu.tw>
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Sender: linux-kernel-owner@vger.kernel.org
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This patch adds a new address/protocol family for LoRaWAN network.
It also implements the the functions and maps to Datagram socket for
LoRaWAN unconfirmed data messages.

Signed-off-by: Jian-Hong Pan <starnight@g.ncu.edu.tw>
---
V2:
- Split the LoRaWAN class module patch in V1 into LoRaWAN socket and
  LoRaWAN Soft MAC modules
- Add lorawan_netdev.h header file for network address related
  declaration
- Use SPDX license identifiers

 include/linux/lora/lorawan_netdev.h |  52 +++
 net/lorawan/Kconfig                 |  10 +
 net/lorawan/Makefile                |   2 +
 net/lorawan/socket.c                | 681 ++++++++++++++++++++++++++++
 4 files changed, 745 insertions(+)
 create mode 100644 include/linux/lora/lorawan_netdev.h
 create mode 100644 net/lorawan/Kconfig
 create mode 100644 net/lorawan/Makefile
 create mode 100644 net/lorawan/socket.c

diff --git a/include/linux/lora/lorawan_netdev.h b/include/linux/lora/lorawan_netdev.h
new file mode 100644
index 000000000000..4adf93fd06c5
--- /dev/null
+++ b/include/linux/lora/lorawan_netdev.h
@@ -0,0 +1,52 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later OR BSD-3-Clause */
+/*-
+ * LoRaWAN stack related definitions
+ *
+ * Copyright (c) 2018 Jian-Hong, Pan <starnight@g.ncu.edu.tw>
+ *
+ */
+
+#ifndef __LORAWAN_NET_DEVICE_H__
+#define __LORAWAN_NET_DEVICE_H__
+
+enum {
+	LRW_ADDR_APPEUI,
+	LRW_ADDR_DEVEUI,
+	LRW_ADDR_DEVADDR,
+};
+
+struct lrw_addr_in {
+	int addr_type;
+	union {
+		u64 app_eui;
+		u64 dev_eui;
+		u32 devaddr;
+	};
+};
+
+struct sockaddr_lorawan {
+	sa_family_t family; /* AF_LORAWAN */
+	struct lrw_addr_in addr_in;
+};
+
+/**
+ * lrw_mac_cb - This structure holds the control buffer (cb) of sk_buff
+ *
+ * @devaddr:	the LoRaWAN device address of this LoRaWAN hardware
+ */
+struct lrw_mac_cb {
+	u32 devaddr;
+};
+
+/**
+ * mac_cb - Get the LoRaWAN MAC control buffer of the sk_buff
+ * @skb:	the exchanging sk_buff
+ *
+ * Return:	the pointer of LoRaWAN MAC control buffer
+ */
+static inline struct lrw_mac_cb * mac_cb(struct sk_buff *skb)
+{
+	return (struct lrw_mac_cb *)skb->cb;
+}
+
+#endif
diff --git a/net/lorawan/Kconfig b/net/lorawan/Kconfig
new file mode 100644
index 000000000000..7f2f344085c4
--- /dev/null
+++ b/net/lorawan/Kconfig
@@ -0,0 +1,10 @@
+config LORAWAN
+	tristate "LoRaWAN Network support"
+	---help---
+	  LoRaWAN defines low data rate, low power and long range wireless
+	  wide area networks. It was designed to organize networks of automation
+	  devices, such as sensors, switches and actuators. It can operate
+	  multiple kilometers wide.
+
+	  Say Y here to compile LoRaWAN support into the kernel or say M to
+	  compile it as a module.
diff --git a/net/lorawan/Makefile b/net/lorawan/Makefile
new file mode 100644
index 000000000000..8c923ca6541a
--- /dev/null
+++ b/net/lorawan/Makefile
@@ -0,0 +1,2 @@
+obj-$(CONFIG_LORAWAN)	+= lorawan.o
+lorawan-objs		:= socket.o
diff --git a/net/lorawan/socket.c b/net/lorawan/socket.c
new file mode 100644
index 000000000000..0c03f7a0fb0e
--- /dev/null
+++ b/net/lorawan/socket.c
@@ -0,0 +1,681 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later OR BSD-3-Clause */
+/*-
+ * LoRaWAN stack related definitions
+ *
+ * Copyright (c) 2018 Jian-Hong, Pan <starnight@g.ncu.edu.tw>
+ *
+ */
+
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/list.h>
+#include <linux/net.h>
+#include <linux/if_arp.h>
+#include <linux/termios.h>		/* For TIOCOUTQ/INQ */
+#include <net/sock.h>
+#include <linux/lora/lorawan_netdev.h>
+
+#define	LORAWAN_MODULE_NAME	"lorawan"
+
+#define	LRW_DBG_STR(fmt)	LORAWAN_MODULE_NAME": "fmt
+#define	lrw_info(fmt, ...)	(pr_info(LRW_DBG_STR(fmt), ##__VA_ARGS__))
+#define	lrw_dbg(fmt, ...)	(pr_debug(LRW_DBG_STR(fmt), ##__VA_ARGS__))
+
+/**
+ * dgram_sock - This structure holds the states of Datagram socket
+ *
+ * @sk:			network layer representation of the socket
+ * 			sk must be the first member of dgram_sock
+ * @src_devaddr:	the LoRaWAN device address for this connection
+ * @bound:		this socket is bound or not
+ * @connected:		this socket is connected to the destination or not
+ * @want_ack:		this socket needs to ack for the connection or not
+ */
+struct dgram_sock {
+	struct sock sk;
+	u32 src_devaddr;
+
+	u8 bound:1;
+	u8 connected:1;
+};
+
+static HLIST_HEAD(dgram_head);
+static DEFINE_RWLOCK(dgram_lock);
+
+static inline struct dgram_sock *
+dgram_sk(const struct sock *sk)
+{
+	return container_of(sk, struct dgram_sock, sk);
+}
+
+static inline struct net_device *
+lrw_get_dev_by_addr(struct net *net, u32 devaddr)
+{
+	struct net_device *ndev = NULL;
+	__be32 be_addr = cpu_to_be32(devaddr);
+
+	rcu_read_lock();
+	ndev = dev_getbyhwaddr_rcu(net, ARPHRD_LORAWAN, (char *)&be_addr);
+	if (ndev)
+		dev_hold(ndev);
+	rcu_read_unlock();
+
+	return ndev;
+}
+
+static int
+dgram_init(struct sock *sk)
+{
+	return 0;
+}
+
+static void
+dgram_close(struct sock *sk, long timeout)
+{
+	sk_common_release(sk);
+}
+
+static int
+dgram_bind(struct sock *sk, struct sockaddr *uaddr, int len)
+{
+	struct sockaddr_lorawan *addr = (struct sockaddr_lorawan *)uaddr;
+	struct dgram_sock *ro = dgram_sk(sk);
+	struct net_device *ndev;
+	int ret;
+
+	lock_sock(sk);
+	ro->bound = 0;
+
+	ret = -EINVAL;
+	if (len < sizeof(*addr))
+		goto dgram_bind_end;
+
+	if (addr->family != AF_LORAWAN)
+		goto dgram_bind_end;
+
+	if (addr->addr_in.addr_type != LRW_ADDR_DEVADDR)
+		goto dgram_bind_end;
+
+	lrw_dbg("%s: bind address %X\n", __func__, addr->addr_in.devaddr);
+	ndev = lrw_get_dev_by_addr(sock_net(sk), addr->addr_in.devaddr);
+	if (!ndev) {
+		ret = -ENODEV;
+		goto dgram_bind_end;
+	}
+	netdev_dbg(ndev, "%s: get ndev\n", __func__);
+
+	if (ndev->type != ARPHRD_LORAWAN) {
+		ret = -ENODEV;
+		goto dgram_bind_end;
+	}
+
+	ro->src_devaddr = addr->addr_in.devaddr;
+	ro->bound = 1;
+	ret = 0;
+	dev_put(ndev);
+	lrw_dbg("%s: bound address %X\n", __func__, ro->src_devaddr);
+
+dgram_bind_end:
+	release_sock(sk);
+	return ret;
+}
+
+static inline int
+lrw_dev_hard_header(struct sk_buff *skb, struct net_device *ndev,
+		    const u32 src_devaddr, size_t len)
+{
+	/* TODO: Prepare the LoRaWAN sending header here */
+	return 0;
+}
+
+static int
+dgram_sendmsg(struct sock *sk, struct msghdr *msg, size_t size)
+{
+	struct dgram_sock *ro = dgram_sk(sk);
+	struct net_device *ndev;
+	struct sk_buff *skb;
+	size_t hlen;
+	size_t tlen;
+	int ret;
+
+	lrw_dbg("%s: going to send %zu bytes", __func__, size);
+	if (msg->msg_flags & MSG_OOB) {
+		lrw_dbg("msg->msg_flags = 0x%x\n", msg->msg_flags);
+		return -EOPNOTSUPP;
+	}
+
+	lrw_dbg("%s: check msg_name\n", __func__);
+	if (!ro->connected && !msg->msg_name)
+		return -EDESTADDRREQ;
+	else if (ro->connected && msg->msg_name)
+		return -EISCONN;
+
+	lrw_dbg("%s: check bound\n", __func__);
+	if (!ro->bound)
+		ndev = dev_getfirstbyhwtype(sock_net(sk), ARPHRD_LORAWAN);
+	else
+		ndev = lrw_get_dev_by_addr(sock_net(sk), ro->src_devaddr);
+
+	if (!ndev) {
+		lrw_dbg("no dev\n");
+		ret = -ENXIO;
+		goto dgram_sendmsg_end;
+	}
+
+	if (size > ndev->mtu){
+		netdev_dbg(ndev, "size = %zu, mtu = %u\n", size, ndev->mtu);
+		ret = -EMSGSIZE;
+		goto dgram_sendmsg_end;
+	}
+
+	netdev_dbg(ndev, "%s: create skb\n", __func__);
+	hlen = LL_RESERVED_SPACE(ndev);
+	tlen = ndev->needed_tailroom;
+	skb = sock_alloc_send_skb(sk, hlen + tlen + size,
+				  msg->msg_flags & MSG_DONTWAIT,
+				  &ret);
+
+	if (!skb)
+		goto dgram_sendmsg_no_skb;
+
+	skb_reserve(skb, hlen);
+	skb_reset_network_header(skb);
+
+	ret = lrw_dev_hard_header(skb, ndev, 0, size);
+	if (ret < 0)
+		goto dgram_sendmsg_no_skb;
+
+	ret = memcpy_from_msg(skb_put(skb, size), msg, size);
+	if (ret > 0)
+		goto dgram_sendmsg_err_skb;
+
+	skb->dev = ndev;
+	skb->protocol = htons(ETH_P_LORAWAN);
+
+	netdev_dbg(ndev, "%s: push skb to xmit queue\n", __func__);
+	ret = dev_queue_xmit(skb);
+	if (ret > 0)
+		ret = net_xmit_errno(ret);
+	netdev_dbg(ndev, "%s: pushed skb to xmit queue with ret=%d\n",
+			 __func__, ret);
+	dev_put(ndev);
+
+	return ret ?: size;
+
+dgram_sendmsg_err_skb:
+	kfree_skb(skb);
+dgram_sendmsg_no_skb:
+	dev_put(ndev);
+
+dgram_sendmsg_end:
+	return ret;
+}
+
+static int
+dgram_recvmsg(struct sock *sk, struct msghdr *msg, size_t len,
+	      int noblock, int flags, int *addr_len)
+{
+	struct sk_buff *skb;
+	size_t copied = 0;
+	DECLARE_SOCKADDR(struct sockaddr_lorawan *, saddr, msg->msg_name);
+	int err;
+
+	skb = skb_recv_datagram(sk, flags, noblock, &err);
+	if (!skb)
+		goto dgram_recvmsg_end;
+
+	copied = skb->len;
+	if (len < copied) {
+		msg->msg_flags |= MSG_TRUNC;
+		copied = len;
+	}
+
+	err = skb_copy_datagram_msg(skb, 0, msg, copied);
+	if (err)
+		goto dgram_recvmsg_done;
+
+	sock_recv_ts_and_drops(msg, sk, skb);
+	if(saddr) {
+		memset(saddr, 0, sizeof(*saddr));
+		saddr->family = AF_LORAWAN;
+		saddr->addr_in.devaddr = mac_cb(skb)->devaddr;
+		*addr_len = sizeof(*saddr);
+	}
+
+	if (flags & MSG_TRUNC)
+		copied = skb->len;
+
+dgram_recvmsg_done:
+	skb_free_datagram(sk, skb);
+
+dgram_recvmsg_end:
+	if (err)
+		return err;
+	return copied;
+}
+
+static int
+dgram_hash(struct sock *sk)
+{
+	lrw_dbg("%s\n", __func__);
+	write_lock_bh(&dgram_lock);
+	sk_add_node(sk, &dgram_head);
+	sock_prot_inuse_add(sock_net(sk), sk->sk_prot, 1);
+	write_unlock_bh(&dgram_lock);
+
+	return 0;
+}
+
+static void
+dgram_unhash(struct sock *sk)
+{
+	lrw_dbg("%s\n", __func__);
+	write_lock_bh(&dgram_lock);
+	if (sk_del_node_init(sk))
+		sock_prot_inuse_add(sock_net(sk), sk->sk_prot, -1);
+	write_unlock_bh(&dgram_lock);
+}
+
+static int
+dgram_connect(struct sock *sk, struct sockaddr *uaddr, int len)
+{
+	struct dgram_sock *ro = dgram_sk(sk);
+
+	/* Nodes of LoRaWAN send data to a gateway only, then data is received
+	 * and transferred to servers with the gateway's policy.
+	 * So, the destination address is not used by nodes.
+	 */
+	lock_sock(sk);
+	ro->connected = 1;
+	release_sock(sk);
+
+	return 0;
+}
+
+static int
+dgram_disconnect(struct sock *sk, int flags)
+{
+	struct dgram_sock *ro = dgram_sk(sk);
+
+	lock_sock(sk);
+	ro->connected = 0;
+	release_sock(sk);
+
+	return 0;
+}
+
+static int
+dgram_ioctl(struct sock *sk, int cmd, unsigned long arg)
+{
+	struct sk_buff *skb;
+	int amount;
+	int err;
+	struct net_device *ndev = sk->sk_dst_cache->dev;
+
+	netdev_dbg(ndev, "%s: ioctl file (cmd=0x%X)\n", __func__, cmd);
+	switch (cmd) {
+	case SIOCOUTQ:
+		amount = sk_wmem_alloc_get(sk);
+		err = put_user(amount, (int __user *)arg);
+		break;
+	case SIOCINQ:
+		amount = 0;
+		spin_lock_bh(&sk->sk_receive_queue.lock);
+		skb = skb_peek(&sk->sk_receive_queue);
+		if (skb) {
+			/* We will only return the amount of this packet
+			 * since that is all that will be read.
+			 */
+			amount = skb->len;
+		}
+		spin_unlock_bh(&sk->sk_receive_queue.lock);
+		err = put_user(amount, (int __user *)arg);
+		break;
+	default:
+		err = -ENOIOCTLCMD;
+	}
+
+	return err;
+}
+
+static int
+dgram_getsockopt(struct sock *sk, int level, int optname,
+		 char __user *optval, int __user *optlen)
+{
+	int val, len;
+
+	if (level != SOL_LORAWAN)
+		return -EOPNOTSUPP;
+
+	if (get_user(len, optlen))
+		return -EFAULT;
+
+	len = min_t(unsigned int, len, sizeof(int));
+
+	switch (optname) {
+	default:
+		return -ENOPROTOOPT;
+	}
+
+	if (put_user(len, optlen))
+		return -EFAULT;
+
+	if (copy_to_user(optval, &val, len))
+		return -EFAULT;
+
+	return 0;
+}
+
+static int
+dgram_setsockopt(struct sock *sk, int level, int optname,
+		 char __user *optval, unsigned int optlen)
+{
+	int val;
+	int err = 0;
+
+	if (optlen < sizeof(int))
+		return -EINVAL;
+
+	if (get_user(val, (int __user *)optval))
+		return -EFAULT;
+
+	lock_sock(sk);
+
+	switch (optname) {
+	default:
+		err = -ENOPROTOOPT;
+		break;
+	}
+
+	release_sock(sk);
+
+	return err;
+}
+
+static struct proto lrw_dgram_prot = {
+	.name		= "LoRaWAN",
+	.owner		= THIS_MODULE,
+	.obj_size	= sizeof(struct dgram_sock),
+	.init		= dgram_init,
+	.close		= dgram_close,
+	.bind		= dgram_bind,
+	.sendmsg	= dgram_sendmsg,
+	.recvmsg	= dgram_recvmsg,
+	.hash		= dgram_hash,
+	.unhash		= dgram_unhash,
+	.connect	= dgram_connect,
+	.disconnect	= dgram_disconnect,
+	.ioctl		= dgram_ioctl,
+	.getsockopt	= dgram_getsockopt,
+	.setsockopt	= dgram_setsockopt,
+};
+
+static int
+lrw_sock_release(struct socket *sock)
+{
+	struct sock *sk = sock->sk;
+
+	if (sk) {
+		sock->sk = NULL;
+		sk->sk_prot->close(sk, 0);
+	}
+
+	return 0;
+}
+
+static int
+lrw_sock_bind(struct socket *sock, struct sockaddr *uaddr, int addr_len)
+{
+	struct sock *sk = sock->sk;
+	struct sockaddr_lorawan *addr = (struct sockaddr_lorawan *)uaddr;
+
+	lrw_dbg("%s: bind address %X\n", __func__, addr->addr_in.devaddr);
+	if (sk->sk_prot->bind)
+		return sk->sk_prot->bind(sk, uaddr, addr_len);
+
+	return sock_no_bind(sock, uaddr, addr_len);
+}
+
+static int
+lrw_sock_connect(struct socket *sock, struct sockaddr *uaddr,
+		 int addr_len, int flags)
+{
+	struct sock *sk = sock->sk;
+
+	if (addr_len < sizeof(uaddr->sa_family))
+		return -EINVAL;
+
+	return sk->sk_prot->connect(sk, uaddr, addr_len);
+}
+
+static int
+lrw_ndev_ioctl(struct sock *sk, struct ifreq __user *arg, unsigned int cmd)
+{
+	struct ifreq ifr;
+	int ret = -ENOIOCTLCMD;
+	struct net_device *ndev;
+
+	lrw_dbg("%s: cmd %ud\n", __func__, cmd);
+	if (copy_from_user(&ifr, arg, sizeof(struct ifreq)))
+		return -EFAULT;
+
+	ifr.ifr_name[IFNAMSIZ-1] = 0;
+
+	dev_load(sock_net(sk), ifr.ifr_name);
+	ndev = dev_get_by_name(sock_net(sk), ifr.ifr_name);
+
+	netdev_dbg(ndev, "%s: cmd %ud\n", __func__, cmd);
+	if (!ndev)
+		return -ENODEV;
+
+	if (ndev->type == ARPHRD_LORAWAN && ndev->netdev_ops->ndo_do_ioctl)
+		ret = ndev->netdev_ops->ndo_do_ioctl(ndev, &ifr, cmd);
+
+	if (!ret && copy_to_user(arg, &ifr, sizeof(struct ifreq)))
+		ret = -EFAULT;
+	dev_put(ndev);
+
+	return ret;
+}
+
+static int
+lrw_sock_ioctl(struct socket *sock, unsigned int cmd, unsigned long arg)
+{
+	struct sock *sk = sock->sk;
+
+	lrw_dbg("%s: cmd %ud\n", __func__, cmd);
+	switch (cmd) {
+	case SIOCGSTAMP:
+		return sock_get_timestamp(sk, (struct timeval __user *)arg);
+	case SIOCGSTAMPNS:
+		return sock_get_timestampns(sk, (struct timespec __user *)arg);
+	case SIOCOUTQ:
+	case SIOCINQ:
+		if (!sk->sk_prot->ioctl)
+			return -ENOIOCTLCMD;
+		return sk->sk_prot->ioctl(sk, cmd, arg);
+	default:
+		return lrw_ndev_ioctl(sk, (struct ifreq __user *)arg, cmd);
+	}
+}
+
+static int
+lrw_sock_sendmsg(struct socket *sock, struct msghdr *msg, size_t len)
+{
+	struct sock *sk = sock->sk;
+
+	lrw_dbg("%s: going to send %zu bytes\n", __func__, len);
+	return sk->sk_prot->sendmsg(sk, msg, len);
+}
+
+static const struct proto_ops lrw_dgram_ops = {
+	.family		= PF_LORAWAN,
+	.owner		= THIS_MODULE,
+	.release	= lrw_sock_release,
+	.bind		= lrw_sock_bind,
+	.connect	= lrw_sock_connect,
+	.socketpair	= sock_no_socketpair,
+	.accept		= sock_no_accept,
+	.getname	= sock_no_getname,
+	.poll		= datagram_poll,
+	.ioctl		= lrw_sock_ioctl,
+	.listen		= sock_no_listen,
+	.shutdown	= sock_no_shutdown,
+	.setsockopt	= sock_common_setsockopt,
+	.getsockopt	= sock_common_getsockopt,
+	.sendmsg	= lrw_sock_sendmsg,
+	.recvmsg	= sock_common_recvmsg,
+	.mmap		= sock_no_mmap,
+	.sendpage	= sock_no_sendpage,
+};
+
+static int
+lorawan_creat(struct net *net, struct socket *sock, int protocol, int kern)
+{
+	struct sock *sk;
+	int ret;
+
+	if (!net_eq(net, &init_net))
+		return -EAFNOSUPPORT;
+
+	if (sock->type != SOCK_DGRAM)
+		return -EAFNOSUPPORT;
+
+	/* Allocates enough memory for dgram_sock whose first member is sk */
+	sk = sk_alloc(net, PF_LORAWAN, GFP_KERNEL, &lrw_dgram_prot, kern);
+	if (!sk)
+		return -ENOMEM;
+
+	sock->ops = &lrw_dgram_ops;
+	sock_init_data(sock, sk);
+	sk->sk_family = PF_LORAWAN;
+	sock_set_flag(sk, SOCK_ZAPPED);
+
+	if (sk->sk_prot->hash) {
+		ret = sk->sk_prot->hash(sk);
+		if (ret) {
+			sk_common_release(sk);
+			goto lorawan_creat_end;
+		}
+	}
+
+	if (sk->sk_prot->init) {
+		ret = sk->sk_prot->init(sk);
+		if (ret)
+			sk_common_release(sk);
+	}
+
+lorawan_creat_end:
+	return ret;
+}
+
+static const struct net_proto_family lorawan_family_ops = {
+	.owner		= THIS_MODULE,
+	.family		= PF_LORAWAN,
+	.create		= lorawan_creat,
+};
+
+static inline int
+lrw_dgram_deliver(struct net_device *ndev, struct sk_buff *skb)
+{
+	struct sock *sk;
+	struct dgram_sock *ro;
+	bool found = false;
+	int ret = NET_RX_SUCCESS;
+
+	read_lock(&dgram_lock);
+	sk_for_each(sk, &dgram_head) {
+		ro = dgram_sk(sk);
+		if(cpu_to_le32(ro->src_devaddr) == *(__le32 *)ndev->dev_addr) {
+			found = true;
+			break;
+		}
+	}
+	read_unlock(&dgram_lock);
+
+	if (!found)
+		goto lrw_dgram_deliver_err;
+
+	skb = skb_share_check(skb, GFP_ATOMIC);
+	if (!skb)
+		return NET_RX_DROP;
+
+	if (sock_queue_rcv_skb(sk, skb) < 0)
+		goto lrw_dgram_deliver_err;
+
+	return ret;
+
+lrw_dgram_deliver_err:
+	kfree_skb(skb);
+	ret = NET_RX_DROP;
+	return ret;
+}
+
+static int
+lorawan_rcv(struct sk_buff *skb, struct net_device *ndev,
+	    struct packet_type *pt, struct net_device *orig_ndev)
+{
+	if (!netif_running(ndev))
+		goto lorawan_rcv_drop;
+
+	if (!net_eq(dev_net(ndev), &init_net))
+		goto lorawan_rcv_drop;
+
+	if (ndev->type != ARPHRD_LORAWAN)
+		goto lorawan_rcv_drop;
+
+	if (skb->pkt_type != PACKET_OTHERHOST)
+		return lrw_dgram_deliver(ndev, skb);
+
+lorawan_rcv_drop:
+	kfree_skb(skb);
+	return NET_RX_DROP;
+}
+
+static struct packet_type lorawan_packet_type = {
+	.type		= htons(ETH_P_LORAWAN),
+	.func		= lorawan_rcv,
+};
+
+static int __init
+lrw_sock_init(void)
+{
+	int ret;
+
+	lrw_info("module inserted\n");
+	ret = proto_register(&lrw_dgram_prot, 1);
+	if(ret)
+		goto lrw_sock_init_end;
+
+	/* Tell SOCKET that we are alive */
+	ret = sock_register(&lorawan_family_ops);
+	if(ret)
+		goto lrw_sock_init_err;
+
+	dev_add_pack(&lorawan_packet_type);
+	ret = 0;
+	goto lrw_sock_init_end;
+
+lrw_sock_init_err:
+	proto_unregister(&lrw_dgram_prot);
+
+lrw_sock_init_end:
+	return 0;
+}
+
+static void __exit
+lrw_sock_exit(void)
+{
+	dev_remove_pack(&lorawan_packet_type);
+	sock_unregister(PF_LORAWAN);
+	proto_unregister(&lrw_dgram_prot);
+	lrw_info("module removed\n");
+}
+
+module_init(lrw_sock_init);
+module_exit(lrw_sock_exit);
+
+MODULE_AUTHOR("Jian-Hong Pan, <starnight@g.ncu.edu.tw>");
+MODULE_DESCRIPTION("LoRaWAN socket kernel module");
+MODULE_LICENSE("Dual BSD/GPL");
+MODULE_ALIAS_NETPROTO(PF_LORAWAN);
-- 
2.19.1