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522 lines
12 KiB
522 lines
12 KiB
// SPDX-License-Identifier: GPL-2.0-or-later |
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/* |
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* "LAPB via ethernet" driver release 001 |
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* |
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* This code REQUIRES 2.1.15 or higher/ NET3.038 |
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* |
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* This is a "pseudo" network driver to allow LAPB over Ethernet. |
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* |
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* This driver can use any ethernet destination address, and can be |
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* limited to accept frames from one dedicated ethernet card only. |
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* |
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* History |
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* LAPBETH 001 Jonathan Naylor Cloned from bpqether.c |
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* 2000-10-29 Henner Eisen lapb_data_indication() return status. |
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* 2000-11-14 Henner Eisen dev_hold/put, NETDEV_GOING_DOWN support |
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*/ |
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#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt |
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#include <linux/errno.h> |
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#include <linux/types.h> |
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#include <linux/socket.h> |
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#include <linux/in.h> |
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#include <linux/slab.h> |
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#include <linux/kernel.h> |
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#include <linux/string.h> |
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#include <linux/net.h> |
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#include <linux/inet.h> |
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#include <linux/netdevice.h> |
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#include <linux/if_arp.h> |
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#include <linux/skbuff.h> |
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#include <net/sock.h> |
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#include <linux/uaccess.h> |
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#include <linux/mm.h> |
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#include <linux/interrupt.h> |
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#include <linux/notifier.h> |
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#include <linux/stat.h> |
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#include <linux/module.h> |
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#include <linux/lapb.h> |
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#include <linux/init.h> |
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#include <net/x25device.h> |
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static const u8 bcast_addr[6] = { 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF }; |
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/* If this number is made larger, check that the temporary string buffer |
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* in lapbeth_new_device is large enough to store the probe device name. |
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*/ |
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#define MAXLAPBDEV 100 |
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struct lapbethdev { |
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struct list_head node; |
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struct net_device *ethdev; /* link to ethernet device */ |
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struct net_device *axdev; /* lapbeth device (lapb#) */ |
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bool up; |
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spinlock_t up_lock; /* Protects "up" */ |
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struct sk_buff_head rx_queue; |
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struct napi_struct napi; |
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}; |
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static LIST_HEAD(lapbeth_devices); |
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static void lapbeth_connected(struct net_device *dev, int reason); |
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static void lapbeth_disconnected(struct net_device *dev, int reason); |
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/* ------------------------------------------------------------------------ */ |
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/* Get the LAPB device for the ethernet device |
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*/ |
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static struct lapbethdev *lapbeth_get_x25_dev(struct net_device *dev) |
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{ |
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struct lapbethdev *lapbeth; |
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list_for_each_entry_rcu(lapbeth, &lapbeth_devices, node, lockdep_rtnl_is_held()) { |
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if (lapbeth->ethdev == dev) |
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return lapbeth; |
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} |
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return NULL; |
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} |
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static __inline__ int dev_is_ethdev(struct net_device *dev) |
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{ |
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return dev->type == ARPHRD_ETHER && strncmp(dev->name, "dummy", 5); |
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} |
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/* ------------------------------------------------------------------------ */ |
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static int lapbeth_napi_poll(struct napi_struct *napi, int budget) |
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{ |
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struct lapbethdev *lapbeth = container_of(napi, struct lapbethdev, |
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napi); |
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struct sk_buff *skb; |
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int processed = 0; |
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for (; processed < budget; ++processed) { |
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skb = skb_dequeue(&lapbeth->rx_queue); |
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if (!skb) |
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break; |
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netif_receive_skb_core(skb); |
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} |
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if (processed < budget) |
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napi_complete(napi); |
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return processed; |
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} |
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/* Receive a LAPB frame via an ethernet interface. |
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*/ |
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static int lapbeth_rcv(struct sk_buff *skb, struct net_device *dev, |
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struct packet_type *ptype, struct net_device *orig_dev) |
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{ |
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int len, err; |
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struct lapbethdev *lapbeth; |
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if (dev_net(dev) != &init_net) |
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goto drop; |
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skb = skb_share_check(skb, GFP_ATOMIC); |
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if (!skb) |
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return NET_RX_DROP; |
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if (!pskb_may_pull(skb, 2)) |
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goto drop; |
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rcu_read_lock(); |
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lapbeth = lapbeth_get_x25_dev(dev); |
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if (!lapbeth) |
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goto drop_unlock_rcu; |
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spin_lock_bh(&lapbeth->up_lock); |
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if (!lapbeth->up) |
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goto drop_unlock; |
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len = skb->data[0] + skb->data[1] * 256; |
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dev->stats.rx_packets++; |
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dev->stats.rx_bytes += len; |
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skb_pull(skb, 2); /* Remove the length bytes */ |
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skb_trim(skb, len); /* Set the length of the data */ |
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err = lapb_data_received(lapbeth->axdev, skb); |
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if (err != LAPB_OK) { |
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printk(KERN_DEBUG "lapbether: lapb_data_received err - %d\n", err); |
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goto drop_unlock; |
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} |
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out: |
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spin_unlock_bh(&lapbeth->up_lock); |
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rcu_read_unlock(); |
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return 0; |
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drop_unlock: |
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kfree_skb(skb); |
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goto out; |
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drop_unlock_rcu: |
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rcu_read_unlock(); |
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drop: |
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kfree_skb(skb); |
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return 0; |
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} |
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static int lapbeth_data_indication(struct net_device *dev, struct sk_buff *skb) |
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{ |
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struct lapbethdev *lapbeth = netdev_priv(dev); |
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unsigned char *ptr; |
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if (skb_cow(skb, 1)) { |
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kfree_skb(skb); |
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return NET_RX_DROP; |
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} |
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skb_push(skb, 1); |
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ptr = skb->data; |
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*ptr = X25_IFACE_DATA; |
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skb->protocol = x25_type_trans(skb, dev); |
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skb_queue_tail(&lapbeth->rx_queue, skb); |
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napi_schedule(&lapbeth->napi); |
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return NET_RX_SUCCESS; |
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} |
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/* Send a LAPB frame via an ethernet interface |
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*/ |
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static netdev_tx_t lapbeth_xmit(struct sk_buff *skb, |
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struct net_device *dev) |
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{ |
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struct lapbethdev *lapbeth = netdev_priv(dev); |
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int err; |
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spin_lock_bh(&lapbeth->up_lock); |
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if (!lapbeth->up) |
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goto drop; |
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/* There should be a pseudo header of 1 byte added by upper layers. |
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* Check to make sure it is there before reading it. |
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*/ |
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if (skb->len < 1) |
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goto drop; |
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switch (skb->data[0]) { |
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case X25_IFACE_DATA: |
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break; |
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case X25_IFACE_CONNECT: |
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err = lapb_connect_request(dev); |
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if (err == LAPB_CONNECTED) |
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lapbeth_connected(dev, LAPB_OK); |
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else if (err != LAPB_OK) |
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pr_err("lapb_connect_request error: %d\n", err); |
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goto drop; |
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case X25_IFACE_DISCONNECT: |
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err = lapb_disconnect_request(dev); |
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if (err == LAPB_NOTCONNECTED) |
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lapbeth_disconnected(dev, LAPB_OK); |
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else if (err != LAPB_OK) |
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pr_err("lapb_disconnect_request err: %d\n", err); |
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fallthrough; |
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default: |
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goto drop; |
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} |
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skb_pull(skb, 1); |
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err = lapb_data_request(dev, skb); |
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if (err != LAPB_OK) { |
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pr_err("lapb_data_request error - %d\n", err); |
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goto drop; |
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} |
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out: |
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spin_unlock_bh(&lapbeth->up_lock); |
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return NETDEV_TX_OK; |
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drop: |
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kfree_skb(skb); |
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goto out; |
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} |
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static void lapbeth_data_transmit(struct net_device *ndev, struct sk_buff *skb) |
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{ |
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struct lapbethdev *lapbeth = netdev_priv(ndev); |
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unsigned char *ptr; |
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struct net_device *dev; |
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int size = skb->len; |
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ptr = skb_push(skb, 2); |
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*ptr++ = size % 256; |
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*ptr++ = size / 256; |
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ndev->stats.tx_packets++; |
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ndev->stats.tx_bytes += size; |
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skb->dev = dev = lapbeth->ethdev; |
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skb->protocol = htons(ETH_P_DEC); |
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skb_reset_network_header(skb); |
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dev_hard_header(skb, dev, ETH_P_DEC, bcast_addr, NULL, 0); |
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dev_queue_xmit(skb); |
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} |
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static void lapbeth_connected(struct net_device *dev, int reason) |
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{ |
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struct lapbethdev *lapbeth = netdev_priv(dev); |
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unsigned char *ptr; |
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struct sk_buff *skb = __dev_alloc_skb(1, GFP_ATOMIC | __GFP_NOMEMALLOC); |
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if (!skb) |
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return; |
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ptr = skb_put(skb, 1); |
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*ptr = X25_IFACE_CONNECT; |
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skb->protocol = x25_type_trans(skb, dev); |
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skb_queue_tail(&lapbeth->rx_queue, skb); |
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napi_schedule(&lapbeth->napi); |
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} |
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static void lapbeth_disconnected(struct net_device *dev, int reason) |
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{ |
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struct lapbethdev *lapbeth = netdev_priv(dev); |
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unsigned char *ptr; |
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struct sk_buff *skb = __dev_alloc_skb(1, GFP_ATOMIC | __GFP_NOMEMALLOC); |
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if (!skb) |
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return; |
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ptr = skb_put(skb, 1); |
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*ptr = X25_IFACE_DISCONNECT; |
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skb->protocol = x25_type_trans(skb, dev); |
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skb_queue_tail(&lapbeth->rx_queue, skb); |
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napi_schedule(&lapbeth->napi); |
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} |
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/* Set AX.25 callsign |
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*/ |
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static int lapbeth_set_mac_address(struct net_device *dev, void *addr) |
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{ |
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struct sockaddr *sa = addr; |
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memcpy(dev->dev_addr, sa->sa_data, dev->addr_len); |
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return 0; |
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} |
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static const struct lapb_register_struct lapbeth_callbacks = { |
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.connect_confirmation = lapbeth_connected, |
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.connect_indication = lapbeth_connected, |
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.disconnect_confirmation = lapbeth_disconnected, |
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.disconnect_indication = lapbeth_disconnected, |
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.data_indication = lapbeth_data_indication, |
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.data_transmit = lapbeth_data_transmit, |
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}; |
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/* open/close a device |
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*/ |
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static int lapbeth_open(struct net_device *dev) |
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{ |
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struct lapbethdev *lapbeth = netdev_priv(dev); |
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int err; |
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napi_enable(&lapbeth->napi); |
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err = lapb_register(dev, &lapbeth_callbacks); |
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if (err != LAPB_OK) { |
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pr_err("lapb_register error: %d\n", err); |
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return -ENODEV; |
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} |
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spin_lock_bh(&lapbeth->up_lock); |
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lapbeth->up = true; |
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spin_unlock_bh(&lapbeth->up_lock); |
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return 0; |
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} |
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static int lapbeth_close(struct net_device *dev) |
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{ |
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struct lapbethdev *lapbeth = netdev_priv(dev); |
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int err; |
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spin_lock_bh(&lapbeth->up_lock); |
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lapbeth->up = false; |
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spin_unlock_bh(&lapbeth->up_lock); |
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err = lapb_unregister(dev); |
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if (err != LAPB_OK) |
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pr_err("lapb_unregister error: %d\n", err); |
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napi_disable(&lapbeth->napi); |
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return 0; |
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} |
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/* ------------------------------------------------------------------------ */ |
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static const struct net_device_ops lapbeth_netdev_ops = { |
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.ndo_open = lapbeth_open, |
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.ndo_stop = lapbeth_close, |
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.ndo_start_xmit = lapbeth_xmit, |
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.ndo_set_mac_address = lapbeth_set_mac_address, |
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}; |
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static void lapbeth_setup(struct net_device *dev) |
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{ |
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dev->netdev_ops = &lapbeth_netdev_ops; |
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dev->needs_free_netdev = true; |
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dev->type = ARPHRD_X25; |
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dev->hard_header_len = 0; |
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dev->mtu = 1000; |
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dev->addr_len = 0; |
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} |
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/* Setup a new device. |
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*/ |
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static int lapbeth_new_device(struct net_device *dev) |
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{ |
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struct net_device *ndev; |
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struct lapbethdev *lapbeth; |
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int rc = -ENOMEM; |
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ASSERT_RTNL(); |
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ndev = alloc_netdev(sizeof(*lapbeth), "lapb%d", NET_NAME_UNKNOWN, |
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lapbeth_setup); |
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if (!ndev) |
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goto out; |
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/* When transmitting data: |
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* first this driver removes a pseudo header of 1 byte, |
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* then the lapb module prepends an LAPB header of at most 3 bytes, |
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* then this driver prepends a length field of 2 bytes, |
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* then the underlying Ethernet device prepends its own header. |
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*/ |
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ndev->needed_headroom = -1 + 3 + 2 + dev->hard_header_len |
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+ dev->needed_headroom; |
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ndev->needed_tailroom = dev->needed_tailroom; |
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lapbeth = netdev_priv(ndev); |
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lapbeth->axdev = ndev; |
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dev_hold(dev); |
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lapbeth->ethdev = dev; |
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lapbeth->up = false; |
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spin_lock_init(&lapbeth->up_lock); |
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skb_queue_head_init(&lapbeth->rx_queue); |
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netif_napi_add(ndev, &lapbeth->napi, lapbeth_napi_poll, 16); |
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rc = -EIO; |
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if (register_netdevice(ndev)) |
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goto fail; |
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list_add_rcu(&lapbeth->node, &lapbeth_devices); |
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rc = 0; |
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out: |
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return rc; |
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fail: |
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dev_put(dev); |
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free_netdev(ndev); |
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goto out; |
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} |
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/* Free a lapb network device. |
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*/ |
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static void lapbeth_free_device(struct lapbethdev *lapbeth) |
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{ |
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dev_put(lapbeth->ethdev); |
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list_del_rcu(&lapbeth->node); |
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unregister_netdevice(lapbeth->axdev); |
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} |
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/* Handle device status changes. |
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* |
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* Called from notifier with RTNL held. |
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*/ |
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static int lapbeth_device_event(struct notifier_block *this, |
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unsigned long event, void *ptr) |
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{ |
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struct lapbethdev *lapbeth; |
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struct net_device *dev = netdev_notifier_info_to_dev(ptr); |
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if (dev_net(dev) != &init_net) |
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return NOTIFY_DONE; |
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if (!dev_is_ethdev(dev)) |
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return NOTIFY_DONE; |
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switch (event) { |
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case NETDEV_UP: |
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/* New ethernet device -> new LAPB interface */ |
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if (!lapbeth_get_x25_dev(dev)) |
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lapbeth_new_device(dev); |
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break; |
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case NETDEV_GOING_DOWN: |
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/* ethernet device closes -> close LAPB interface */ |
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lapbeth = lapbeth_get_x25_dev(dev); |
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if (lapbeth) |
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dev_close(lapbeth->axdev); |
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break; |
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case NETDEV_UNREGISTER: |
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/* ethernet device disappears -> remove LAPB interface */ |
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lapbeth = lapbeth_get_x25_dev(dev); |
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if (lapbeth) |
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lapbeth_free_device(lapbeth); |
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break; |
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} |
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return NOTIFY_DONE; |
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} |
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/* ------------------------------------------------------------------------ */ |
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static struct packet_type lapbeth_packet_type __read_mostly = { |
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.type = cpu_to_be16(ETH_P_DEC), |
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.func = lapbeth_rcv, |
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}; |
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static struct notifier_block lapbeth_dev_notifier = { |
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.notifier_call = lapbeth_device_event, |
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}; |
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static const char banner[] __initconst = |
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KERN_INFO "LAPB Ethernet driver version 0.02\n"; |
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static int __init lapbeth_init_driver(void) |
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{ |
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dev_add_pack(&lapbeth_packet_type); |
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register_netdevice_notifier(&lapbeth_dev_notifier); |
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printk(banner); |
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return 0; |
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} |
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module_init(lapbeth_init_driver); |
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static void __exit lapbeth_cleanup_driver(void) |
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{ |
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struct lapbethdev *lapbeth; |
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struct list_head *entry, *tmp; |
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dev_remove_pack(&lapbeth_packet_type); |
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unregister_netdevice_notifier(&lapbeth_dev_notifier); |
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rtnl_lock(); |
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list_for_each_safe(entry, tmp, &lapbeth_devices) { |
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lapbeth = list_entry(entry, struct lapbethdev, node); |
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dev_put(lapbeth->ethdev); |
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unregister_netdevice(lapbeth->axdev); |
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} |
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rtnl_unlock(); |
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} |
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module_exit(lapbeth_cleanup_driver); |
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MODULE_AUTHOR("Jonathan Naylor <[email protected]>"); |
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MODULE_DESCRIPTION("The unofficial LAPB over Ethernet driver"); |
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MODULE_LICENSE("GPL");
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