[RFC,net-next,04/15] net: Add lora subsystem

diff --git a/include/linux/lora/skb.h b/include/linux/lora/skb.h
new file mode 100644
index 000000000000..8806741464d0
--- /dev/null
+++ b/include/linux/lora/skb.h
@@ -0,0 +1,29 @@ 
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/*
+ * linux/lora/skb.h
+ *
+ * Copyright (c) 2017-2018 Andreas Färber
+ */
+#ifndef _LORA_SKB_H
+#define _LORA_SKB_H
+
+#include <linux/types.h>
+#include <linux/skbuff.h>
+
+struct lora_skb_priv {
+	int ifindex;
+};
+
+static inline struct lora_skb_priv *lora_skb_prv(struct sk_buff *skb)
+{
+	return (struct lora_skb_priv *)(skb->head);
+}
+
+static inline void lora_skb_reserve(struct sk_buff *skb)
+{
+	skb_reserve(skb, sizeof(struct lora_skb_priv));
+}
+
+struct sk_buff *alloc_lora_skb(struct net_device *dev, u8 **data);
+
+#endif /* _LORA_SKB_H */
diff --git a/net/Kconfig b/net/Kconfig
index f738a6f27665..d294ecc50a3b 100644
--- a/net/Kconfig
+++ b/net/Kconfig
@@ -223,6 +223,7 @@  source "net/phonet/Kconfig"
 source "net/6lowpan/Kconfig"
 source "net/ieee802154/Kconfig"
 source "net/mac802154/Kconfig"
+source "net/lora/Kconfig"
 source "net/sched/Kconfig"
 source "net/dcb/Kconfig"
 source "net/dns_resolver/Kconfig"
diff --git a/net/Makefile b/net/Makefile
index bdaf53925acd..e80b84313851 100644
--- a/net/Makefile
+++ b/net/Makefile
@@ -62,6 +62,7 @@  endif
 obj-$(CONFIG_6LOWPAN)		+= 6lowpan/
 obj-$(CONFIG_IEEE802154)	+= ieee802154/
 obj-$(CONFIG_MAC802154)		+= mac802154/
+obj-$(CONFIG_LORA)		+= lora/
 
 ifeq ($(CONFIG_NET),y)
 obj-$(CONFIG_SYSCTL)		+= sysctl_net.o
diff --git a/net/lora/Kconfig b/net/lora/Kconfig
new file mode 100644
index 000000000000..44972ea8769f
--- /dev/null
+++ b/net/lora/Kconfig
@@ -0,0 +1,9 @@ 
+#
+# LoRa
+#
+
+menuconfig LORA
+	depends on NET
+	tristate "LoRa subsystem support"
+	help
+	  LoRa ...
diff --git a/net/lora/Makefile b/net/lora/Makefile
new file mode 100644
index 000000000000..b58675ef7846
--- /dev/null
+++ b/net/lora/Makefile
@@ -0,0 +1,8 @@ 
+#
+# LoRa
+#
+
+obj-$(CONFIG_LORA) += lora.o
+
+lora-y := af_lora.o
+lora-y += dgram.o
diff --git a/net/lora/af_lora.c b/net/lora/af_lora.c
new file mode 100644
index 000000000000..662482fe4c9b
--- /dev/null
+++ b/net/lora/af_lora.c
@@ -0,0 +1,152 @@ 
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright (c) 2017-2018 Andreas Färber
+ */
+
+#include <linux/if_arp.h>
+#include <linux/lora.h>
+#include <linux/module.h>
+#include <linux/net.h>
+#include <linux/socket.h>
+#include <net/sock.h>
+
+#include "af_lora.h"
+
+int lora_send(struct sk_buff *skb)
+{
+	int ret;
+
+	pr_debug("lora: %s\n", __func__);
+
+	skb->protocol = htons(ETH_P_LORA);
+
+	if (unlikely(skb->len > skb->dev->mtu)) {
+		ret = -EMSGSIZE;
+		goto err_skb;
+	}
+
+	if (unlikely(skb->dev->type != ARPHRD_LORA)) {
+		ret = -EPERM;
+		goto err_skb;
+	}
+
+	if (unlikely(!(skb->dev->flags & IFF_UP))) {
+		ret = -ENETDOWN;
+		goto err_skb;
+	}
+
+	skb->ip_summed = CHECKSUM_UNNECESSARY;
+
+	skb_reset_mac_header(skb);
+	skb_reset_network_header(skb);
+	skb_reset_transport_header(skb);
+
+	if (false) {
+		skb->pkt_type = PACKET_LOOPBACK;
+	} else
+		skb->pkt_type = PACKET_HOST;
+
+	ret = dev_queue_xmit(skb);
+	if (ret > 0)
+		ret = net_xmit_errno(ret);
+	if (ret)
+		return ret;
+
+	return 0;
+
+err_skb:
+	kfree_skb(skb);
+	return ret;
+}
+EXPORT_SYMBOL(lora_send);
+
+static void lora_sock_destruct(struct sock *sk)
+{
+	pr_debug("lora: %s\n", __func__);
+
+	skb_queue_purge(&sk->sk_receive_queue);
+}
+
+static int lora_create(struct net *net, struct socket *sock, int protocol,
+		       int kern)
+{
+	struct sock *sk;
+
+	pr_debug("lora: %s\n", __func__);
+
+	sock->state = SS_UNCONNECTED;
+
+	if (protocol < 0 || protocol > LORA_NPROTO)
+		return -EINVAL;
+
+	/*if (!net_eq(net, &init_net))
+		return -EAFNOSUPPORT;*/
+
+	if (sock->type != SOCK_DGRAM)
+		return -ESOCKTNOSUPPORT;
+
+	sock->ops = &dgram_proto_ops;
+
+	sk = sk_alloc(net, PF_LORA, GFP_KERNEL, &dgram_proto, kern);
+	if (!sk)
+		return -ENOMEM;
+
+	sock_init_data(sock, sk);
+	sk->sk_family = PF_LORA;
+	sk->sk_destruct = lora_sock_destruct;
+
+	if (sk->sk_prot->init) {
+		int ret = sk->sk_prot->init(sk);
+		if (ret) {
+			sock_orphan(sk);
+			sock_put(sk);
+			return ret;
+		}
+	}
+
+	return 0;
+}
+
+static const struct net_proto_family lora_net_proto_family = {
+	.family = PF_LORA,
+	.owner = THIS_MODULE,
+	.create = lora_create,
+};
+
+static __init int lora_init(void)
+{
+	int ret;
+
+	pr_debug("lora: init\n");
+
+	ret = proto_register(&dgram_proto, 1);
+	if (ret)
+		goto err_dgram;
+
+	ret = sock_register(&lora_net_proto_family);
+	if (ret)
+		goto err_sock;
+
+	return 0;
+
+err_sock:
+	proto_unregister(&dgram_proto);
+err_dgram:
+	return ret;
+}
+
+static __exit void lora_exit(void)
+{
+	pr_debug("lora: exit\n");
+
+	sock_unregister(PF_LORA);
+	proto_unregister(&dgram_proto);
+}
+
+module_init(lora_init);
+module_exit(lora_exit);
+
+MODULE_DESCRIPTION("LoRa PF_LORA core");
+MODULE_AUTHOR("Andreas Färber <afaerber@suse.de>");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS_NETPROTO(PF_LORA);
diff --git a/net/lora/af_lora.h b/net/lora/af_lora.h
new file mode 100644
index 000000000000..47dd863531b2
--- /dev/null
+++ b/net/lora/af_lora.h
@@ -0,0 +1,13 @@ 
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/*
+ * Copyright (c) 2017-2018 Andreas Färber
+ */
+#ifndef AF_LORA_H
+#define AF_LORA_H
+
+extern struct proto dgram_proto;
+extern const struct proto_ops dgram_proto_ops;
+
+int lora_send(struct sk_buff *skb);
+
+#endif /* AF_LORA_H */
diff --git a/net/lora/dgram.c b/net/lora/dgram.c
new file mode 100644
index 000000000000..4d931fd3778a
--- /dev/null
+++ b/net/lora/dgram.c
@@ -0,0 +1,293 @@ 
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright (c) 2017-2018 Andreas Färber
+ */
+
+#include <linux/if_arp.h>
+#include <linux/if_ether.h>
+#include <linux/lora.h>
+#include <linux/module.h>
+#include <linux/net.h>
+#include <linux/socket.h>
+#include <linux/version.h>
+#include <linux/lora/skb.h>
+#include <net/sock.h>
+
+#include "af_lora.h"
+
+struct dgram_sock {
+	struct sock sk;
+	int ifindex;
+	bool bound;
+	struct notifier_block notifier;
+};
+
+static inline struct dgram_sock *dgram_sk(const struct sock *sk)
+{
+	return (struct dgram_sock *)sk;
+}
+
+static int dgram_bind(struct socket *sock, struct sockaddr *uaddr, int len)
+{
+	struct sockaddr_lora *addr = (struct sockaddr_lora *)uaddr;
+	struct sock *sk = sock->sk;
+	struct dgram_sock *dgram = dgram_sk(sk);
+	int ifindex;
+	int ret = 0;
+	bool notify_enetdown = false;
+
+	pr_debug("lora: %s\n", __func__);
+
+	if (len < sizeof(*addr))
+		return -EINVAL;
+
+	lock_sock(sk);
+
+	if (dgram->bound && addr->lora_ifindex == dgram->ifindex)
+		goto out;
+
+	if (addr->lora_ifindex) {
+		struct net_device *netdev;
+
+		netdev = dev_get_by_index(sock_net(sk), addr->lora_ifindex);
+		if (!netdev) {
+			ret = -ENODEV;
+			goto out;
+		}
+		if (netdev->type != ARPHRD_LORA) {
+			dev_put(netdev);
+			ret = -ENODEV;
+			goto out;
+		}
+		if (!(netdev->flags & IFF_UP))
+			notify_enetdown = true;
+
+		ifindex = netdev->ifindex;
+
+		dev_put(netdev);
+	} else
+		ifindex = 0;
+
+	dgram->ifindex = ifindex;
+	dgram->bound = true;
+
+out:
+	release_sock(sk);
+
+	if (notify_enetdown) {
+		sk->sk_err = ENETDOWN;
+		if (!sock_flag(sk, SOCK_DEAD))
+			sk->sk_error_report(sk);
+	}
+
+	return ret;
+}
+
+static int dgram_sendmsg(struct socket *sock, struct msghdr *msg, size_t size)
+{
+	struct sock *sk = sock->sk;
+	struct dgram_sock *dgram = dgram_sk(sk);
+	struct sk_buff *skb;
+	struct net_device *netdev;
+	int ifindex;
+	int ret;
+
+	pr_debug("lora: %s\n", __func__);
+
+	if (msg->msg_name) {
+		DECLARE_SOCKADDR(struct sockaddr_lora *, addr, msg->msg_name);
+
+		if (msg->msg_namelen < sizeof(*addr))
+			return -EINVAL;
+
+		if (addr->lora_family != AF_LORA)
+			return -EINVAL;
+
+		ifindex = addr->lora_ifindex;
+	} else
+		ifindex = dgram->ifindex;
+
+	netdev = dev_get_by_index(sock_net(sk), ifindex);
+	if (!netdev)
+		return -ENXIO;
+
+	skb = sock_alloc_send_skb(sk, size + sizeof(struct lora_skb_priv),
+				  msg->msg_flags & MSG_DONTWAIT, &ret);
+	if (!skb)
+		goto err_sock_alloc_send_skb;
+
+	lora_skb_reserve(skb);
+	lora_skb_prv(skb)->ifindex = netdev->ifindex;
+
+	ret = memcpy_from_msg(skb_put(skb, size), msg, size);
+	if (ret < 0)
+		goto err_memcpy_from_msg;
+
+	sock_tx_timestamp(sk,
+			  sk->sk_tsflags,
+			  &skb_shinfo(skb)->tx_flags);
+
+	skb->dev = netdev;
+	skb->sk = sk;
+	skb->priority = sk->sk_priority;
+
+	ret = lora_send(skb);
+
+	dev_put(netdev);
+
+	if (ret)
+		return ret;
+
+	return size;
+
+err_memcpy_from_msg:
+	kfree_skb(skb);
+err_sock_alloc_send_skb:
+	dev_put(netdev);
+	return ret;
+}
+
+static int dgram_ioctl(struct socket *sock, unsigned int cmd, unsigned long arg)
+{
+	pr_debug("lora: %s\n", __func__);
+
+	return -ENOIOCTLCMD;
+}
+
+static int dgram_getname(struct socket *sock, struct sockaddr *uaddr,
+#if LINUX_VERSION_CODE < KERNEL_VERSION(4, 13, 0)
+			 int *len,
+#endif
+			 int peer)
+{
+	struct sockaddr_lora *addr = (struct sockaddr_lora *)uaddr;
+	struct sock *sk = sock->sk;
+	struct dgram_sock *dgram = dgram_sk(sk);
+
+	pr_debug("lora: %s\n", __func__);
+
+	if (peer)
+		return -EOPNOTSUPP;
+
+	memset(addr, 0, sizeof(*addr));
+	addr->lora_family = AF_LORA;
+	addr->lora_ifindex = dgram->ifindex;
+
+#if LINUX_VERSION_CODE >= KERNEL_VERSION(4, 13, 0)
+	return sizeof(*addr);
+#else
+	*len = sizeof(*addr);
+	return 0;
+#endif
+}
+
+static int dgram_release(struct socket *sock)
+{
+	struct sock *sk = sock->sk;
+	struct dgram_sock *dgram;
+
+	pr_debug("lora: %s\n", __func__);
+
+	if (!sk)
+		return 0;
+
+	dgram = dgram_sk(sk);
+
+	unregister_netdevice_notifier(&dgram->notifier);
+
+	lock_sock(sk);
+
+	dgram->ifindex = 0;
+	dgram->bound = false;
+
+	sock_orphan(sk);
+	sock->sk = NULL;
+
+	release_sock(sk);
+	sock_put(sk);
+
+	return 0;
+}
+
+const struct proto_ops dgram_proto_ops = {
+	.family		= PF_LORA,
+	.release	= dgram_release,
+	.bind		= dgram_bind,
+	.connect	= sock_no_connect,
+	.socketpair	= sock_no_socketpair,
+	.accept		= sock_no_accept,
+	.getname	= dgram_getname,
+	.poll		= datagram_poll,
+	.ioctl		= dgram_ioctl,
+	.listen		= sock_no_listen,
+	.shutdown	= sock_no_shutdown,
+	.setsockopt	= sock_no_setsockopt,
+	.getsockopt	= sock_no_getsockopt,
+	.sendmsg	= dgram_sendmsg,
+	.recvmsg	= sock_no_recvmsg,
+	.mmap		= sock_no_mmap,
+	.sendpage	= sock_no_sendpage,
+};
+
+static int dgram_notifier(struct notifier_block *nb, unsigned long msg, void *ptr)
+{
+	struct net_device *netdev = netdev_notifier_info_to_dev(ptr);
+	struct dgram_sock *dgram = container_of(nb, struct dgram_sock, notifier);
+	struct sock *sk = &dgram->sk;
+
+	pr_debug("lora: %s\n", __func__);
+
+	if (!net_eq(dev_net(netdev), sock_net(sk)))
+		return NOTIFY_DONE;
+
+	if (netdev->type != ARPHRD_LORA)
+		return NOTIFY_DONE;
+
+	if (dgram->ifindex != netdev->ifindex)
+		return NOTIFY_DONE;
+
+	switch (msg) {
+	case NETDEV_UNREGISTER:
+		lock_sock(sk);
+
+		dgram->ifindex = 0;
+		dgram->bound = false;
+
+		release_sock(sk);
+
+		sk->sk_err = ENODEV;
+		if (!sock_flag(sk, SOCK_DEAD))
+			sk->sk_error_report(sk);
+		break;
+
+	case NETDEV_DOWN:
+		sk->sk_err = ENETDOWN;
+		if (!sock_flag(sk, SOCK_DEAD))
+			sk->sk_error_report(sk);
+		break;
+	}
+
+	return NOTIFY_DONE;
+}
+
+static int dgram_init(struct sock *sk)
+{
+	struct dgram_sock *dgram = dgram_sk(sk);
+
+	pr_debug("lora: %s\n", __func__);
+
+	dgram->bound = false;
+	dgram->ifindex = 0;
+
+	dgram->notifier.notifier_call = dgram_notifier;
+	register_netdevice_notifier(&dgram->notifier);
+
+	return 0;
+}
+
+struct proto dgram_proto __read_mostly = {
+	.name = "LoRa",
+	.owner = THIS_MODULE,
+	.obj_size = sizeof(struct dgram_sock),
+	.init = dgram_init,
+};