- 根目录:
- net
- bluetooth
- 6lowpan.c
/*
Copyright (c) 2013 Intel Corp.
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/if_arp.h>
#include <linux/netdevice.h>
#include <linux/etherdevice.h>
#include <net/ipv6.h>
#include <net/ip6_route.h>
#include <net/addrconf.h>
#include <net/af_ieee802154.h> /* to get the address type */
#include <net/bluetooth/bluetooth.h>
#include <net/bluetooth/hci_core.h>
#include <net/bluetooth/l2cap.h>
#include "6lowpan.h"
#include "../ieee802154/6lowpan.h" /* for the compression support */
#define IFACE_NAME_TEMPLATE "bt%d"
#define EUI64_ADDR_LEN 8
struct skb_cb {
struct in6_addr addr;
struct l2cap_conn *conn;
};
#define lowpan_cb(skb) ((struct skb_cb *)((skb)->cb))
/* The devices list contains those devices that we are acting
* as a proxy. The BT 6LoWPAN device is a virtual device that
* connects to the Bluetooth LE device. The real connection to
* BT device is done via l2cap layer. There exists one
* virtual device / one BT 6LoWPAN network (=hciX device).
* The list contains struct lowpan_dev elements.
*/
static LIST_HEAD(bt_6lowpan_devices);
static DEFINE_RWLOCK(devices_lock);
struct lowpan_peer {
struct list_head list;
struct l2cap_conn *conn;
/* peer addresses in various formats */
unsigned char eui64_addr[EUI64_ADDR_LEN];
struct in6_addr peer_addr;
};
struct lowpan_dev {
struct list_head list;
struct hci_dev *hdev;
struct net_device *netdev;
struct list_head peers;
atomic_t peer_count; /* number of items in peers list */
struct work_struct delete_netdev;
struct delayed_work notify_peers;
};
static inline struct lowpan_dev *lowpan_dev(const struct net_device *netdev)
{
return netdev_priv(netdev);
}
static inline void peer_add(struct lowpan_dev *dev, struct lowpan_peer *peer)
{
list_add(&peer->list, &dev->peers);
atomic_inc(&dev->peer_count);
}
static inline bool peer_del(struct lowpan_dev *dev, struct lowpan_peer *peer)
{
list_del(&peer->list);
if (atomic_dec_and_test(&dev->peer_count)) {
BT_DBG("last peer");
return true;
}
return false;
}
static inline struct lowpan_peer *peer_lookup_ba(struct lowpan_dev *dev,
bdaddr_t *ba, __u8 type)
{
struct lowpan_peer *peer, *tmp;
BT_DBG("peers %d addr %pMR type %d", atomic_read(&dev->peer_count),
ba, type);
list_for_each_entry_safe(peer, tmp, &dev->peers, list) {
BT_DBG("addr %pMR type %d",
&peer->conn->hcon->dst, peer->conn->hcon->dst_type);
if (bacmp(&peer->conn->hcon->dst, ba))
continue;
if (type == peer->conn->hcon->dst_type)
return peer;
}
return NULL;
}
static inline struct lowpan_peer *peer_lookup_conn(struct lowpan_dev *dev,
struct l2cap_conn *conn)
{
struct lowpan_peer *peer, *tmp;
list_for_each_entry_safe(peer, tmp, &dev->peers, list) {
if (peer->conn == conn)
return peer;
}
return NULL;
}
static struct lowpan_peer *lookup_peer(struct l2cap_conn *conn)
{
struct lowpan_dev *entry, *tmp;
struct lowpan_peer *peer = NULL;
unsigned long flags;
read_lock_irqsave(&devices_lock, flags);
list_for_each_entry_safe(entry, tmp, &bt_6lowpan_devices, list) {
peer = peer_lookup_conn(entry, conn);
if (peer)
break;
}
read_unlock_irqrestore(&devices_lock, flags);
return peer;
}
static struct lowpan_dev *lookup_dev(struct l2cap_conn *conn)
{
struct lowpan_dev *entry, *tmp;
struct lowpan_dev *dev = NULL;
unsigned long flags;
read_lock_irqsave(&devices_lock, flags);
list_for_each_entry_safe(entry, tmp, &bt_6lowpan_devices, list) {
if (conn->hcon->hdev == entry->hdev) {
dev = entry;
break;
}
}
read_unlock_irqrestore(&devices_lock, flags);
return dev;
}
static int give_skb_to_upper(struct sk_buff *skb, struct net_device *dev)
{
struct sk_buff *skb_cp;
int ret;
skb_cp = skb_copy(skb, GFP_ATOMIC);
if (!skb_cp)
return -ENOMEM;
ret = netif_rx(skb_cp);
BT_DBG("receive skb %d", ret);
if (ret < 0)
return NET_RX_DROP;
return ret;
}
static int process_data(struct sk_buff *skb, struct net_device *netdev,
struct l2cap_conn *conn)
{
const u8 *saddr, *daddr;
u8 iphc0, iphc1;
struct lowpan_dev *dev;
struct lowpan_peer *peer;
unsigned long flags;
dev = lowpan_dev(netdev);
read_lock_irqsave(&devices_lock, flags);
peer = peer_lookup_conn(dev, conn);
read_unlock_irqrestore(&devices_lock, flags);
if (!peer)
goto drop;
saddr = peer->eui64_addr;
daddr = dev->netdev->dev_addr;
/* at least two bytes will be used for the encoding */
if (skb->len < 2)
goto drop;
if (lowpan_fetch_skb_u8(skb, &iphc0))
goto drop;
if (lowpan_fetch_skb_u8(skb, &iphc1))
goto drop;
return lowpan_process_data(skb, netdev,
saddr, IEEE802154_ADDR_LONG, EUI64_ADDR_LEN,
daddr, IEEE802154_ADDR_LONG, EUI64_ADDR_LEN,
iphc0, iphc1, give_skb_to_upper);
drop:
kfree_skb(skb);
return -EINVAL;
}
static int recv_pkt(struct sk_buff *skb, struct net_device *dev,
struct l2cap_conn *conn)
{
struct sk_buff *local_skb;
int ret;
if (!netif_running(dev))
goto drop;
if (dev->type != ARPHRD_6LOWPAN)
goto drop;
/* check that it's our buffer */
if (skb->data[0] == LOWPAN_DISPATCH_IPV6) {
/* Copy the packet so that the IPv6 header is
* properly aligned.
*/
local_skb = skb_copy_expand(skb, NET_SKB_PAD - 1,
skb_tailroom(skb), GFP_ATOMIC);
if (!local_skb)
goto drop;
local_skb->protocol = htons(ETH_P_IPV6);
local_skb->pkt_type = PACKET_HOST;
skb_reset_network_header(local_skb);
skb_set_transport_header(local_skb, sizeof(struct ipv6hdr));
if (give_skb_to_upper(local_skb, dev) != NET_RX_SUCCESS) {
kfree_skb(local_skb);
goto drop;
}
dev->stats.rx_bytes += skb->len;
dev->stats.rx_packets++;
kfree_skb(local_skb);
kfree_skb(skb);
} else {
switch (skb->data[0] & 0xe0) {
case LOWPAN_DISPATCH_IPHC: /* ipv6 datagram */
local_skb = skb_clone(skb, GFP_ATOMIC);
if (!local_skb)
goto drop;
ret = process_data(local_skb, dev, conn);
if (ret != NET_RX_SUCCESS)
goto drop;
dev->stats.rx_bytes += skb->len;
dev->stats.rx_packets++;
kfree_skb(skb);
break;
default:
break;
}
}
return NET_RX_SUCCESS;
drop:
kfree_skb(skb);
return NET_RX_DROP;
}
/* Packet from BT LE device */
int bt_6lowpan_recv(struct l2cap_conn *conn, struct sk_buff *skb)
{
struct lowpan_dev *dev;
struct lowpan_peer *peer;
int err;
peer = lookup_peer(conn);
if (!peer)
return -ENOENT;
dev = lookup_dev(conn);
if (!dev || !dev->netdev)
return -ENOENT;
err = recv_pkt(skb, dev->netdev, conn);
BT_DBG("recv pkt %d", err);
return err;
}
static inline int skbuff_copy(void *msg, int len, int count, int mtu,
struct sk_buff *skb, struct net_device *dev)
{
struct sk_buff **frag;
int sent = 0;
memcpy(skb_put(skb, count), msg, count);
sent += count;
msg += count;
len -= count;
dev->stats.tx_bytes += count;
dev->stats.tx_packets++;
raw_dump_table(__func__, "Sending", skb->data, skb->len);
/* Continuation fragments (no L2CAP header) */
frag = &skb_shinfo(skb)->frag_list;
while (len > 0) {
struct sk_buff *tmp;
count = min_t(unsigned int, mtu, len);
tmp = bt_skb_alloc(count, GFP_ATOMIC);
if (!tmp)
return -ENOMEM;
*frag = tmp;
memcpy(skb_put(*frag, count), msg, count);
raw_dump_table(__func__, "Sending fragment",
(*frag)->data, count);
(*frag)->priority = skb->priority;
sent += count;
msg += count;
len -= count;
skb->len += (*frag)->len;
skb->data_len += (*frag)->len;
frag = &(*frag)->next;
dev->stats.tx_bytes += count;
dev->stats.tx_packets++;
}
return sent;
}
static struct sk_buff *create_pdu(struct l2cap_conn *conn, void *msg,
size_t len, u32 priority,
struct net_device *dev)
{
struct sk_buff *skb;
int err, count;
struct l2cap_hdr *lh;
/* FIXME: This mtu check should be not needed and atm is only used for
* testing purposes
*/
if (conn->mtu > (L2CAP_LE_MIN_MTU + L2CAP_HDR_SIZE))
conn->mtu = L2CAP_LE_MIN_MTU + L2CAP_HDR_SIZE;
count = min_t(unsigned int, (conn->mtu - L2CAP_HDR_SIZE), len);
BT_DBG("conn %p len %zu mtu %d count %d", conn, len, conn->mtu, count);
skb = bt_skb_alloc(count + L2CAP_HDR_SIZE, GFP_ATOMIC);
if (!skb)
return ERR_PTR(-ENOMEM);
skb->priority = priority;
lh = (struct l2cap_hdr *)skb_put(skb, L2CAP_HDR_SIZE);
lh->cid = cpu_to_le16(L2CAP_FC_6LOWPAN);
lh->len = cpu_to_le16(len);
err = skbuff_copy(msg, len, count, conn->mtu, skb, dev);
if (unlikely(err < 0)) {
kfree_skb(skb);
BT_DBG("skbuff copy %d failed", err);
return ERR_PTR(err);
}
return skb;
}
static int conn_send(struct l2cap_conn *conn,
void *msg, size_t len, u32 priority,
struct net_device *dev)
{
struct sk_buff *skb;
skb = create_pdu(conn, msg, len, priority, dev);
if (IS_ERR(skb))
return -EINVAL;
BT_DBG("conn %p skb %p len %d priority %u", conn, skb, skb->len,
skb->priority);
hci_send_acl(conn->hchan, skb, ACL_START);
return 0;
}
static void get_dest_bdaddr(struct in6_addr *ip6_daddr,
bdaddr_t *addr, u8 *addr_type)
{
u8 *eui64;
eui64 = ip6_daddr->s6_addr + 8;
addr->b[0] = eui64[7];
addr->b[1] = eui64[6];
addr->b[2] = eui64[5];
addr->b[3] = eui64[2];
addr->b[4] = eui64[1];
addr->b[5] = eui64[0];
addr->b[5] ^= 2;
/* Set universal/local bit to 0 */
if (addr->b[5] & 1) {
addr->b[5] &= ~1;
*addr_type = ADDR_LE_DEV_PUBLIC;
} else {
*addr_type = ADDR_LE_DEV_RANDOM;
}
}
static int header_create(struct sk_buff *skb, struct net_device *netdev,
unsigned short type, const void *_daddr,
const void *_saddr, unsigned int len)
{
struct ipv6hdr *hdr;
struct lowpan_dev *dev;
struct lowpan_peer *peer;
bdaddr_t addr, *any = BDADDR_ANY;
u8 *saddr, *daddr = any->b;
u8 addr_type;
if (type != ETH_P_IPV6)
return -EINVAL;
hdr = ipv6_hdr(skb);
dev = lowpan_dev(netdev);
if (ipv6_addr_is_multicast(&hdr->daddr)) {
memcpy(&lowpan_cb(skb)->addr, &hdr->daddr,
sizeof(struct in6_addr));
lowpan_cb(skb)->conn = NULL;
} else {
unsigned long flags;
/* Get destination BT device from skb.
* If there is no such peer then discard the packet.
*/
get_dest_bdaddr(&hdr->daddr, &addr, &addr_type);
BT_DBG("dest addr %pMR type %d", &addr, addr_type);
read_lock_irqsave(&devices_lock, flags);
peer = peer_lookup_ba(dev, &addr, addr_type);
read_unlock_irqrestore(&devices_lock, flags);
if (!peer) {
BT_DBG("no such peer %pMR found", &addr);
return -ENOENT;
}
daddr = peer->eui64_addr;
memcpy(&lowpan_cb(skb)->addr, &hdr->daddr,
sizeof(struct in6_addr));
lowpan_cb(skb)->conn = peer->conn;
}
saddr = dev->netdev->dev_addr;
return lowpan_header_compress(skb, netdev, type, daddr, saddr, len);
}
/* Packet to BT LE device */
static int send_pkt(struct l2cap_conn *conn, const void *saddr,
const void *daddr, struct sk_buff *skb,
struct net_device *netdev)
{
raw_dump_table(__func__, "raw skb data dump before fragmentation",
skb->data, skb->len);
return conn_send(conn, skb->data, skb->len, 0, netdev);
}
static void send_mcast_pkt(struct sk_buff *skb, struct net_device *netdev)
{
struct sk_buff *local_skb;
struct lowpan_dev *entry, *tmp;
unsigned long flags;
read_lock_irqsave(&devices_lock, flags);
list_for_each_entry_safe(entry, tmp, &bt_6lowpan_devices, list) {
struct lowpan_peer *pentry, *ptmp;
struct lowpan_dev *dev;
if (entry->netdev != netdev)
continue;
dev = lowpan_dev(entry->netdev);
list_for_each_entry_safe(pentry, ptmp, &dev->peers, list) {
local_skb = skb_clone(skb, GFP_ATOMIC);
send_pkt(pentry->conn, netdev->dev_addr,
pentry->eui64_addr, local_skb, netdev);
kfree_skb(local_skb);
}
}
read_unlock_irqrestore(&devices_lock, flags);
}
static netdev_tx_t bt_xmit(struct sk_buff *skb, struct net_device *netdev)
{
int err = 0;
unsigned char *eui64_addr;
struct lowpan_dev *dev;
struct lowpan_peer *peer;
bdaddr_t addr;
u8 addr_type;
if (ipv6_addr_is_multicast(&lowpan_cb(skb)->addr)) {
/* We need to send the packet to every device
* behind this interface.
*/
send_mcast_pkt(skb, netdev);
} else {
unsigned long flags;
get_dest_bdaddr(&lowpan_cb(skb)->addr, &addr, &addr_type);
eui64_addr = lowpan_cb(skb)->addr.s6_addr + 8;
dev = lowpan_dev(netdev);
read_lock_irqsave(&devices_lock, flags);
peer = peer_lookup_ba(dev, &addr, addr_type);
read_unlock_irqrestore(&devices_lock, flags);
BT_DBG("xmit from %s to %pMR (%pI6c) peer %p", netdev->name,
&addr, &lowpan_cb(skb)->addr, peer);
if (peer && peer->conn)
err = send_pkt(peer->conn, netdev->dev_addr,
eui64_addr, skb, netdev);
}
dev_kfree_skb(skb);
if (err)
BT_DBG("ERROR: xmit failed (%d)", err);
return (err < 0) ? NET_XMIT_DROP : err;
}
static const struct net_device_ops netdev_ops = {
.ndo_start_xmit = bt_xmit,
};
static struct header_ops header_ops = {
.create = header_create,
};
static void netdev_setup(struct net_device *dev)
{
dev->addr_len = EUI64_ADDR_LEN;
dev->type = ARPHRD_6LOWPAN;
dev->hard_header_len = 0;
dev->needed_tailroom = 0;
dev->mtu = IPV6_MIN_MTU;
dev->tx_queue_len = 0;
dev->flags = IFF_RUNNING | IFF_POINTOPOINT;
dev->watchdog_timeo = 0;
dev->netdev_ops = &netdev_ops;
dev->header_ops = &header_ops;
dev->destructor = free_netdev;
}
static struct device_type bt_type = {
.name = "bluetooth",
};
static void set_addr(u8 *eui, u8 *addr, u8 addr_type)
{
/* addr is the BT address in little-endian format */
eui[0] = addr[5];
eui[1] = addr[4];
eui[2] = addr[3];
eui[3] = 0xFF;
eui[4] = 0xFE;
eui[5] = addr[2];
eui[6] = addr[1];
eui[7] = addr[0];
eui[0] ^= 2;
/* Universal/local bit set, RFC 4291 */
if (addr_type == ADDR_LE_DEV_PUBLIC)
eui[0] |= 1;
else
eui[0] &= ~1;
}
static void set_dev_addr(struct net_device *netdev, bdaddr_t *addr,
u8 addr_type)
{
netdev->addr_assign_type = NET_ADDR_PERM;
set_addr(netdev->dev_addr, addr->b, addr_type);
netdev->dev_addr[0] ^= 2;
}
static void ifup(struct net_device *netdev)
{
int err;
rtnl_lock();
err = dev_open(netdev);
if (err < 0)
BT_INFO("iface %s cannot be opened (%d)", netdev->name, err);
rtnl_unlock();
}
static void do_notify_peers(struct work_struct *work)
{
struct lowpan_dev *dev = container_of(work, struct lowpan_dev,
notify_peers.work);
netdev_notify_peers(dev->netdev); /* send neighbour adv at startup */
}
static bool is_bt_6lowpan(struct hci_conn *hcon)
{
if (hcon->type != LE_LINK)
return false;
return test_bit(HCI_CONN_6LOWPAN, &hcon->flags);
}
static int add_peer_conn(struct l2cap_conn *conn, struct lowpan_dev *dev)
{
struct lowpan_peer *peer;
unsigned long flags;
peer = kzalloc(sizeof(*peer), GFP_ATOMIC);
if (!peer)
return -ENOMEM;
peer->conn = conn;
memset(&peer->peer_addr, 0, sizeof(struct in6_addr));
/* RFC 2464 ch. 5 */
peer->peer_addr.s6_addr[0] = 0xFE;
peer->peer_addr.s6_addr[1] = 0x80;
set_addr((u8 *)&peer->peer_addr.s6_addr + 8, conn->hcon->dst.b,
conn->hcon->dst_type);
memcpy(&peer->eui64_addr, (u8 *)&peer->peer_addr.s6_addr + 8,
EUI64_ADDR_LEN);
peer->eui64_addr[0] ^= 2; /* second bit-flip (Universe/Local)
* is done according RFC2464
*/
raw_dump_inline(__func__, "peer IPv6 address",
(unsigned char *)&peer->peer_addr, 16);
raw_dump_inline(__func__, "peer EUI64 address", peer->eui64_addr, 8);
write_lock_irqsave(&devices_lock, flags);
INIT_LIST_HEAD(&peer->list);
peer_add(dev, peer);
write_unlock_irqrestore(&devices_lock, flags);
/* Notifying peers about us needs to be done without locks held */
INIT_DELAYED_WORK(&dev->notify_peers, do_notify_peers);
schedule_delayed_work(&dev->notify_peers, msecs_to_jiffies(100));
return 0;
}
/* This gets called when BT LE 6LoWPAN device is connected. We then
* create network device that acts as a proxy between BT LE device
* and kernel network stack.
*/
int bt_6lowpan_add_conn(struct l2cap_conn *conn)
{
struct lowpan_peer *peer = NULL;
struct lowpan_dev *dev;
struct net_device *netdev;
int err = 0;
unsigned long flags;
if (!is_bt_6lowpan(conn->hcon))
return 0;
peer = lookup_peer(conn);
if (peer)
return -EEXIST;
dev = lookup_dev(conn);
if (dev)
return add_peer_conn(conn, dev);
netdev = alloc_netdev(sizeof(*dev), IFACE_NAME_TEMPLATE, netdev_setup);
if (!netdev)
return -ENOMEM;
set_dev_addr(netdev, &conn->hcon->src, conn->hcon->src_type);
netdev->netdev_ops = &netdev_ops;
SET_NETDEV_DEV(netdev, &conn->hcon->dev);
SET_NETDEV_DEVTYPE(netdev, &bt_type);
err = register_netdev(netdev);
if (err < 0) {
BT_INFO("register_netdev failed %d", err);
free_netdev(netdev);
goto out;
}
BT_DBG("ifindex %d peer bdaddr %pMR my addr %pMR",
netdev->ifindex, &conn->hcon->dst, &conn->hcon->src);
set_bit(__LINK_STATE_PRESENT, &netdev->state);
dev = netdev_priv(netdev);
dev->netdev = netdev;
dev->hdev = conn->hcon->hdev;
INIT_LIST_HEAD(&dev->peers);
write_lock_irqsave(&devices_lock, flags);
INIT_LIST_HEAD(&dev->list);
list_add(&dev->list, &bt_6lowpan_devices);
write_unlock_irqrestore(&devices_lock, flags);
ifup(netdev);
return add_peer_conn(conn, dev);
out:
return err;
}
static void delete_netdev(struct work_struct *work)
{
struct lowpan_dev *entry = container_of(work, struct lowpan_dev,
delete_netdev);
unregister_netdev(entry->netdev);
/* The entry pointer is deleted in device_event() */
}
int bt_6lowpan_del_conn(struct l2cap_conn *conn)
{
struct lowpan_dev *entry, *tmp;
struct lowpan_dev *dev = NULL;
struct lowpan_peer *peer;
int err = -ENOENT;
unsigned long flags;
bool last = false;
if (!conn || !is_bt_6lowpan(conn->hcon))
return 0;
write_lock_irqsave(&devices_lock, flags);
list_for_each_entry_safe(entry, tmp, &bt_6lowpan_devices, list) {
dev = lowpan_dev(entry->netdev);
peer = peer_lookup_conn(dev, conn);
if (peer) {
last = peer_del(dev, peer);
err = 0;
break;
}
}
if (!err && last && dev && !atomic_read(&dev->peer_count)) {
write_unlock_irqrestore(&devices_lock, flags);
cancel_delayed_work_sync(&dev->notify_peers);
/* bt_6lowpan_del_conn() is called with hci dev lock held which
* means that we must delete the netdevice in worker thread.
*/
INIT_WORK(&entry->delete_netdev, delete_netdev);
schedule_work(&entry->delete_netdev);
} else {
write_unlock_irqrestore(&devices_lock, flags);
}
return err;
}
static int device_event(struct notifier_block *unused,
unsigned long event, void *ptr)
{
struct net_device *netdev = netdev_notifier_info_to_dev(ptr);
struct lowpan_dev *entry, *tmp;
unsigned long flags;
if (netdev->type != ARPHRD_6LOWPAN)
return NOTIFY_DONE;
switch (event) {
case NETDEV_UNREGISTER:
write_lock_irqsave(&devices_lock, flags);
list_for_each_entry_safe(entry, tmp, &bt_6lowpan_devices,
list) {
if (entry->netdev == netdev) {
list_del(&entry->list);
kfree(entry);
break;
}
}
write_unlock_irqrestore(&devices_lock, flags);
break;
}
return NOTIFY_DONE;
}
static struct notifier_block bt_6lowpan_dev_notifier = {
.notifier_call = device_event,
};
int bt_6lowpan_init(void)
{
return register_netdevice_notifier(&bt_6lowpan_dev_notifier);
}
void bt_6lowpan_cleanup(void)
{
unregister_netdevice_notifier(&bt_6lowpan_dev_notifier);
}