Jian-Hong Pan [off-list ref] 於 2019年1月7日 週一 下午10:47寫道：

Andreas Färber [off-list ref] 於 2018年12月29日 週六 下午3:27寫道：

quoted

Hi Jian-Hong,

Am 16.12.18 um 11:18 schrieb Jian-Hong Pan:

quoted

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 <redacted>

[...]

quoted

 include/linux/lora/lorawan_netdev.h |  52 +++
 net/lorawan/Kconfig                 |  10 +
 net/lorawan/Makefile                |   2 +
 net/lorawan/socket.c                | 686 ++++++++++++++++++++++++++++
 4 files changed, 750 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

I'm not 100% happy with this yet, but to decouple it from the soft-MAC
discussion (patches 2-6/6) and to allow reuse by Ben, I've staged it in
linux-lora.git.

We can clean it up with incremental patches there (and squash later).

quoted

diff --git a/include/linux/lora/lorawan_netdev.h b/include/linux/lora/lorawan_netdev.h
new file mode 100644
index 000000000000..5bffb5164f95
--- /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 */

Is there any practical reason you dual-license your code? My LoRa code
is only GPL - should I reconsider that?

I use dual-license due to the event "[Ksummit-discuss] [CORE TOPIC]
GPL defense issues"
https://lists.linuxfoundation.org/pipermail/ksummit-discuss/2016-August/003580.html

quoted

quoted

+/*-

I assume the dash is a typo?

quoted

+ * LoRaWAN stack related definitions
+ *
+ * Copyright (c) 2018 Jian-Hong, Pan [off-list ref]
+ *

Leftover white line from old license header?

quoted

+ */
+
+#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;

In my RFC and in linux-lora.git I have a lora_eui typedef - any reason
you're not using it here?

lora_eui is defined as a type of u8 array with 8 bytes in
include/linux/lora/dev.h
typedef u8 lora_eui[8];
It is not a basic nor simple data type.

1. There is the endian issue.  LoRaWAN uses little endian for
transmission.  If u64 data type is used, we can call functions like
cpu_to_le64 and le64_to_cpu to deal the endian jobs directly.
2. We can compare the EUIs with relational operators directly if the
EUI is not a type of array.

quoted

quoted

+             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;
+};
+
+/**
+ * lrw_get_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 *lrw_get_mac_cb(struct sk_buff *skb)
+{
+     return (struct lrw_mac_cb *)skb->cb;
+}

For LoRa I have a separate lora/skb.h - suggest to split this off into
its own header consistently.

Sounds good.
Do you prefer separate them into lora/skb.h or lora/lorawan_skb.h?

quoted

quoted

+
+#endif

diff --git a/net/lorawan/Kconfig b/net/lorawan/Kconfig
new file mode 100644
index 000000000000..bf6c9b77573b
--- /dev/null
+++ b/net/lorawan/Kconfig

@@ -0,0 +1,10 @@
+config LORAWAN
+     tristate "LoRaWAN Network support"

The N in LoRaWAN is already for Network. :)

quoted

+     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.

The missing information here to distinguish it from LoRa would be that
it's a client/server technology centered around gateways. In particular
gateways that anyone can run, distinguishing it from (Sigfox or) NB-IoT.

quoted

+
+       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

Both Kconfig and Makefile are not integrated into net/ here. That
happens only in 6/6.

quoted

diff --git a/net/lorawan/socket.c b/net/lorawan/socket.c
new file mode 100644
index 000000000000..7ef106b877ca
--- /dev/null
+++ b/net/lorawan/socket.c

@@ -0,0 +1,686 @@
+// SPDX-License-Identifier: GPL-2.0-or-later OR BSD-3-Clause
+/*-

?

quoted

+ * LoRaWAN stack related definitions
+ *
+ * Copyright (c) 2018 Jian-Hong, Pan [off-list ref]
+ *

?

quoted

+ */
+
+#define      LORAWAN_MODULE_NAME     "lorawan"
+
+#define      pr_fmt(fmt)             LORAWAN_MODULE_NAME ": " fmt
+
+#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>

Please sort headers alphabetically.

quoted

+
+/**
+ * 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

Might that sentence be more useful as inline comment below?

quoted

+ * @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

Doesn't exist below?

quoted

+ */
+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 struct dgram_sock *
+dgram_sk(const struct sock *sk)
+{
+     return container_of(sk, struct dgram_sock, sk);
+}
+
+static struct net_device *
+lrw_get_dev_by_addr(struct net *net, u32 devaddr)
+{
+     __be32 be_addr = cpu_to_be32(devaddr);
+     struct net_device *ndev = NULL;
+
+     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;
+
+     pr_debug("%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;

This is leaking ndev.

quoted

+     }
+
+     ro->src_devaddr = addr->addr_in.devaddr;
+     ro->bound = 1;
+     ret = 0;
+     dev_put(ndev);
+     pr_debug("%s: bound address %X\n", __func__, ro->src_devaddr);
+
+dgram_bind_end:
+     release_sock(sk);
+     return ret;
+}
+
+static 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 */

I wonder, is your idea that you would always write headers here but have
me ignore them in hard-MAC drivers by accessing data and not head?

I.e., does this dgram (and a later seqpacket) implementation give us not
just the buffer to pass to hard-MAC or soft-MAC but actually LoRa, too,
so that maclorawan needs to further post-processing of header/checksum?

I put lrw_dev_hard_header function here for the header processing nnd
thought it might be called in the future originally.  However, as you
mentioned, we already have soft and hard-MAC and this abstraction
layer only pass the buffer.  So, it can be removed now.

quoted

quoted

+     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;
+
+     pr_debug("%s: going to send %zu bytes", __func__, size);

\n

quoted

+     if (msg->msg_flags & MSG_OOB) {
+             pr_debug("msg->msg_flags = 0x%x\n", msg->msg_flags);
+             return -EOPNOTSUPP;
+     }
+
+     pr_debug("%s: check msg_name\n", __func__);
+     if (!ro->connected && !msg->msg_name)
+             return -EDESTADDRREQ;
+     else if (ro->connected && msg->msg_name)
+             return -EISCONN;
+
+     pr_debug("%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) {
+             pr_debug("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;

Leaks at least ndev from lrw_get_dev_by_addr.

quoted

+     }
+
+     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)
+{
+     DECLARE_SOCKADDR(struct sockaddr_lorawan *, saddr, msg->msg_name);
+     struct sk_buff *skb;
+     size_t copied = 0;
+     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 = lrw_get_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)
+{
+     pr_debug("%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)
+{
+     pr_debug("%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 net_device *ndev = sk->sk_dst_cache->dev;
+     struct sk_buff *skb;
+     int amount;
+     int err;
+
+     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;
+
+     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 sockaddr_lorawan *addr = (struct sockaddr_lorawan *)uaddr;
+     struct sock *sk = sock->sk;
+
+     pr_debug("%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 net_device *ndev;
+     struct ifreq ifr;
+     int ret;
+
+     pr_debug("%s: cmd %ud\n", __func__, cmd);
+     ret = -ENOIOCTLCMD;
+
+     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;
+
+     pr_debug("%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;
+
+     pr_debug("%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)

create
Also, why lorawan_ here and lrw_ elsewhere?

quoted

+{
+     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:

create

quoted

+     return ret;
+}
+
+static const struct net_proto_family lorawan_family_ops = {
+     .owner          = THIS_MODULE,
+     .family         = PF_LORAWAN,
+     .create         = lorawan_creat,
+};
+
+static int
+lrw_dgram_deliver(struct net_device *ndev, struct sk_buff *skb)
+{
+     struct dgram_sock *ro;
+     struct sock *sk;
+     bool found;
+     int ret;
+
+     ret = NET_RX_SUCCESS;
+     found = false;

In times of C99 you could probably fold that into the declarations.

I have thought this issue many times, but give up and just follow
"Reverse XMAS tree declarations" rule in net subsystem. [1]
David also gave the related review comment. [2]

[1] https://lore.kernel.org/patchwork/patch/732076/
[2] https://lkml.org/lkml/2018/11/5/916

Regards,
Jian-Hong Pan

quoted

quoted

+
+     read_lock(&dgram_lock);
+     sk_for_each(sk, &dgram_head) {
+             ro = dgram_sk(sk);
+             if (cpu_to_be32(ro->src_devaddr) == *(__be32 *)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;
+
+     pr_info("module inserted\n");
+     ret = proto_register(&lrw_dgram_prot, 1);
+     if (ret)
+             goto lrw_sock_init_end;
+
+     /* Tell SOCKET that we are alive */

Drop?

quoted

+     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;

return ret;?

quoted

+}
+
+static void __exit
+lrw_sock_exit(void)
+{
+     dev_remove_pack(&lorawan_packet_type);
+     sock_unregister(PF_LORAWAN);
+     proto_unregister(&lrw_dgram_prot);
+     pr_info("module removed\n");
+}
+
+module_init(lrw_sock_init);
+module_exit(lrw_sock_exit);
+
+MODULE_AUTHOR("Jian-Hong Pan, [off-list ref]");

Drop the comma?

quoted

+MODULE_DESCRIPTION("LoRaWAN socket kernel module");

Aren't they all kernel modules? :)

quoted

+MODULE_LICENSE("Dual BSD/GPL");
+MODULE_ALIAS_NETPROTO(PF_LORAWAN);

Thanks for the reviewing.  Preparing the fixing patches now. :)

Jain-Hong Pan