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linux/net/caif/chnl_net.c

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/*
* Copyright (C) ST-Ericsson AB 2010
* Authors: Sjur Brendeland
* Daniel Martensson
* License terms: GNU General Public License (GPL) version 2
*/
#define pr_fmt(fmt) KBUILD_MODNAME ":%s(): " fmt, __func__
#include <linux/fs.h>
#include <linux/hardirq.h>
#include <linux/init.h>
#include <linux/module.h>
#include <linux/netdevice.h>
#include <linux/if_ether.h>
#include <linux/ip.h>
#include <linux/sched.h>
#include <linux/sockios.h>
#include <linux/caif/if_caif.h>
#include <net/rtnetlink.h>
#include <net/caif/caif_layer.h>
#include <net/caif/cfpkt.h>
#include <net/caif/caif_dev.h>
/* GPRS PDP connection has MTU to 1500 */
#define GPRS_PDP_MTU 1500
/* 5 sec. connect timeout */
#define CONNECT_TIMEOUT (5 * HZ)
#define CAIF_NET_DEFAULT_QUEUE_LEN 500
#define UNDEF_CONNID 0xffffffff
/*This list is protected by the rtnl lock. */
static LIST_HEAD(chnl_net_list);
MODULE_LICENSE("GPL");
MODULE_ALIAS_RTNL_LINK("caif");
enum caif_states {
CAIF_CONNECTED = 1,
CAIF_CONNECTING,
CAIF_DISCONNECTED,
CAIF_SHUTDOWN
};
struct chnl_net {
struct cflayer chnl;
struct caif_connect_request conn_req;
struct list_head list_field;
struct net_device *netdev;
char name[256];
wait_queue_head_t netmgmt_wq;
/* Flow status to remember and control the transmission. */
bool flowenabled;
enum caif_states state;
};
static void robust_list_del(struct list_head *delete_node)
{
struct list_head *list_node;
struct list_head *n;
ASSERT_RTNL();
list_for_each_safe(list_node, n, &chnl_net_list) {
if (list_node == delete_node) {
list_del(list_node);
return;
}
}
WARN_ON(1);
}
static int chnl_recv_cb(struct cflayer *layr, struct cfpkt *pkt)
{
struct sk_buff *skb;
struct chnl_net *priv;
int pktlen;
const u8 *ip_version;
u8 buf;
priv = container_of(layr, struct chnl_net, chnl);
if (!priv)
return -EINVAL;
skb = (struct sk_buff *) cfpkt_tonative(pkt);
/* Get length of CAIF packet. */
pktlen = skb->len;
/* Pass some minimum information and
* send the packet to the net stack.
*/
skb->dev = priv->netdev;
/* check the version of IP */
ip_version = skb_header_pointer(skb, 0, 1, &buf);
if (!ip_version) {
kfree_skb(skb);
return -EINVAL;
}
switch (*ip_version >> 4) {
case 4:
skb->protocol = htons(ETH_P_IP);
break;
case 6:
skb->protocol = htons(ETH_P_IPV6);
break;
default:
kfree_skb(skb);
priv->netdev->stats.rx_errors++;
return -EINVAL;
}
/* If we change the header in loop mode, the checksum is corrupted. */
if (priv->conn_req.protocol == CAIFPROTO_DATAGRAM_LOOP)
skb->ip_summed = CHECKSUM_UNNECESSARY;
else
skb->ip_summed = CHECKSUM_NONE;
if (in_interrupt())
netif_rx(skb);
else
netif_rx_ni(skb);
/* Update statistics. */
priv->netdev->stats.rx_packets++;
priv->netdev->stats.rx_bytes += pktlen;
return 0;
}
static int delete_device(struct chnl_net *dev)
{
ASSERT_RTNL();
if (dev->netdev)
unregister_netdevice(dev->netdev);
return 0;
}
static void close_work(struct work_struct *work)
{
struct chnl_net *dev = NULL;
struct list_head *list_node;
struct list_head *_tmp;
rtnl_lock();
list_for_each_safe(list_node, _tmp, &chnl_net_list) {
dev = list_entry(list_node, struct chnl_net, list_field);
if (dev->state == CAIF_SHUTDOWN)
dev_close(dev->netdev);
}
rtnl_unlock();
}
static DECLARE_WORK(close_worker, close_work);
static void chnl_hold(struct cflayer *lyr)
{
struct chnl_net *priv = container_of(lyr, struct chnl_net, chnl);
dev_hold(priv->netdev);
}
static void chnl_put(struct cflayer *lyr)
{
struct chnl_net *priv = container_of(lyr, struct chnl_net, chnl);
dev_put(priv->netdev);
}
static void chnl_flowctrl_cb(struct cflayer *layr, enum caif_ctrlcmd flow,
int phyid)
{
struct chnl_net *priv = container_of(layr, struct chnl_net, chnl);
pr_debug("NET flowctrl func called flow: %s\n",
flow == CAIF_CTRLCMD_FLOW_ON_IND ? "ON" :
flow == CAIF_CTRLCMD_INIT_RSP ? "INIT" :
flow == CAIF_CTRLCMD_FLOW_OFF_IND ? "OFF" :
flow == CAIF_CTRLCMD_DEINIT_RSP ? "CLOSE/DEINIT" :
flow == CAIF_CTRLCMD_INIT_FAIL_RSP ? "OPEN_FAIL" :
flow == CAIF_CTRLCMD_REMOTE_SHUTDOWN_IND ?
"REMOTE_SHUTDOWN" : "UKNOWN CTRL COMMAND");
switch (flow) {
case CAIF_CTRLCMD_FLOW_OFF_IND:
priv->flowenabled = false;
netif_stop_queue(priv->netdev);
break;
case CAIF_CTRLCMD_DEINIT_RSP:
priv->state = CAIF_DISCONNECTED;
break;
case CAIF_CTRLCMD_INIT_FAIL_RSP:
priv->state = CAIF_DISCONNECTED;
wake_up_interruptible(&priv->netmgmt_wq);
break;
case CAIF_CTRLCMD_REMOTE_SHUTDOWN_IND:
priv->state = CAIF_SHUTDOWN;
netif_tx_disable(priv->netdev);
schedule_work(&close_worker);
break;
case CAIF_CTRLCMD_FLOW_ON_IND:
priv->flowenabled = true;
netif_wake_queue(priv->netdev);
break;
case CAIF_CTRLCMD_INIT_RSP:
caif_client_register_refcnt(&priv->chnl, chnl_hold, chnl_put);
priv->state = CAIF_CONNECTED;
priv->flowenabled = true;
netif_wake_queue(priv->netdev);
wake_up_interruptible(&priv->netmgmt_wq);
break;
default:
break;
}
}
static int chnl_net_start_xmit(struct sk_buff *skb, struct net_device *dev)
{
struct chnl_net *priv;
struct cfpkt *pkt = NULL;
int len;
int result = -1;
/* Get our private data. */
priv = netdev_priv(dev);
if (skb->len > priv->netdev->mtu) {
pr_warn("Size of skb exceeded MTU\n");
kfree_skb(skb);
dev->stats.tx_errors++;
return NETDEV_TX_OK;
}
if (!priv->flowenabled) {
pr_debug("dropping packets flow off\n");
kfree_skb(skb);
dev->stats.tx_dropped++;
return NETDEV_TX_OK;
}
if (priv->conn_req.protocol == CAIFPROTO_DATAGRAM_LOOP)
swap(ip_hdr(skb)->saddr, ip_hdr(skb)->daddr);
/* Store original SKB length. */
len = skb->len;
pkt = cfpkt_fromnative(CAIF_DIR_OUT, (void *) skb);
/* Send the packet down the stack. */
result = priv->chnl.dn->transmit(priv->chnl.dn, pkt);
if (result) {
dev->stats.tx_dropped++;
return NETDEV_TX_OK;
}
/* Update statistics. */
dev->stats.tx_packets++;
dev->stats.tx_bytes += len;
return NETDEV_TX_OK;
}
static int chnl_net_open(struct net_device *dev)
{
struct chnl_net *priv = NULL;
int result = -1;
int llifindex, headroom, tailroom, mtu;
struct net_device *lldev;
ASSERT_RTNL();
priv = netdev_priv(dev);
if (!priv) {
pr_debug("chnl_net_open: no priv\n");
return -ENODEV;
}
if (priv->state != CAIF_CONNECTING) {
priv->state = CAIF_CONNECTING;
result = caif_connect_client(dev_net(dev), &priv->conn_req,
&priv->chnl, &llifindex,
&headroom, &tailroom);
if (result != 0) {
pr_debug("err: "
"Unable to register and open device,"
" Err:%d\n",
result);
goto error;
}
lldev = __dev_get_by_index(dev_net(dev), llifindex);
if (lldev == NULL) {
pr_debug("no interface?\n");
result = -ENODEV;
goto error;
}
dev->needed_tailroom = tailroom + lldev->needed_tailroom;
dev->hard_header_len = headroom + lldev->hard_header_len +
lldev->needed_tailroom;
/*
* MTU, head-room etc is not know before we have a
* CAIF link layer device available. MTU calculation may
* override initial RTNL configuration.
* MTU is minimum of current mtu, link layer mtu pluss
* CAIF head and tail, and PDP GPRS contexts max MTU.
*/
mtu = min_t(int, dev->mtu, lldev->mtu - (headroom + tailroom));
mtu = min_t(int, GPRS_PDP_MTU, mtu);
dev_set_mtu(dev, mtu);
if (mtu < 100) {
pr_warn("CAIF Interface MTU too small (%d)\n", mtu);
result = -ENODEV;
goto error;
}
}
rtnl_unlock(); /* Release RTNL lock during connect wait */
result = wait_event_interruptible_timeout(priv->netmgmt_wq,
priv->state != CAIF_CONNECTING,
CONNECT_TIMEOUT);
rtnl_lock();
if (result == -ERESTARTSYS) {
pr_debug("wait_event_interruptible woken by a signal\n");
result = -ERESTARTSYS;
goto error;
}
if (result == 0) {
pr_debug("connect timeout\n");
caif_disconnect_client(dev_net(dev), &priv->chnl);
priv->state = CAIF_DISCONNECTED;
pr_debug("state disconnected\n");
result = -ETIMEDOUT;
goto error;
}
if (priv->state != CAIF_CONNECTED) {
pr_debug("connect failed\n");
result = -ECONNREFUSED;
goto error;
}
pr_debug("CAIF Netdevice connected\n");
return 0;
error:
caif_disconnect_client(dev_net(dev), &priv->chnl);
priv->state = CAIF_DISCONNECTED;
pr_debug("state disconnected\n");
return result;
}
static int chnl_net_stop(struct net_device *dev)
{
struct chnl_net *priv;
ASSERT_RTNL();
priv = netdev_priv(dev);
priv->state = CAIF_DISCONNECTED;
caif_disconnect_client(dev_net(dev), &priv->chnl);
return 0;
}
static int chnl_net_init(struct net_device *dev)
{
struct chnl_net *priv;
ASSERT_RTNL();
priv = netdev_priv(dev);
strncpy(priv->name, dev->name, sizeof(priv->name));
return 0;
}
static void chnl_net_uninit(struct net_device *dev)
{
struct chnl_net *priv;
ASSERT_RTNL();
priv = netdev_priv(dev);
robust_list_del(&priv->list_field);
}
static const struct net_device_ops netdev_ops = {
.ndo_open = chnl_net_open,
.ndo_stop = chnl_net_stop,
.ndo_init = chnl_net_init,
.ndo_uninit = chnl_net_uninit,
.ndo_start_xmit = chnl_net_start_xmit,
};
static void chnl_net_destructor(struct net_device *dev)
{
struct chnl_net *priv = netdev_priv(dev);
caif_free_client(&priv->chnl);
}
static void ipcaif_net_setup(struct net_device *dev)
{
struct chnl_net *priv;
dev->netdev_ops = &netdev_ops;
net: Fix inconsistent teardown and release of private netdev state. Network devices can allocate reasources and private memory using netdev_ops->ndo_init(). However, the release of these resources can occur in one of two different places. Either netdev_ops->ndo_uninit() or netdev->destructor(). The decision of which operation frees the resources depends upon whether it is necessary for all netdev refs to be released before it is safe to perform the freeing. netdev_ops->ndo_uninit() presumably can occur right after the NETDEV_UNREGISTER notifier completes and the unicast and multicast address lists are flushed. netdev->destructor(), on the other hand, does not run until the netdev references all go away. Further complicating the situation is that netdev->destructor() almost universally does also a free_netdev(). This creates a problem for the logic in register_netdevice(). Because all callers of register_netdevice() manage the freeing of the netdev, and invoke free_netdev(dev) if register_netdevice() fails. If netdev_ops->ndo_init() succeeds, but something else fails inside of register_netdevice(), it does call ndo_ops->ndo_uninit(). But it is not able to invoke netdev->destructor(). This is because netdev->destructor() will do a free_netdev() and then the caller of register_netdevice() will do the same. However, this means that the resources that would normally be released by netdev->destructor() will not be. Over the years drivers have added local hacks to deal with this, by invoking their destructor parts by hand when register_netdevice() fails. Many drivers do not try to deal with this, and instead we have leaks. Let's close this hole by formalizing the distinction between what private things need to be freed up by netdev->destructor() and whether the driver needs unregister_netdevice() to perform the free_netdev(). netdev->priv_destructor() performs all actions to free up the private resources that used to be freed by netdev->destructor(), except for free_netdev(). netdev->needs_free_netdev is a boolean that indicates whether free_netdev() should be done at the end of unregister_netdevice(). Now, register_netdevice() can sanely release all resources after ndo_ops->ndo_init() succeeds, by invoking both ndo_ops->ndo_uninit() and netdev->priv_destructor(). And at the end of unregister_netdevice(), we invoke netdev->priv_destructor() and optionally call free_netdev(). Signed-off-by: David S. Miller <davem@davemloft.net>
2017-05-08 09:52:56 -07:00
dev->needs_free_netdev = true;
dev->priv_destructor = chnl_net_destructor;
dev->flags |= IFF_NOARP;
dev->flags |= IFF_POINTOPOINT;
dev->mtu = GPRS_PDP_MTU;
dev->tx_queue_len = CAIF_NET_DEFAULT_QUEUE_LEN;
priv = netdev_priv(dev);
priv->chnl.receive = chnl_recv_cb;
priv->chnl.ctrlcmd = chnl_flowctrl_cb;
priv->netdev = dev;
priv->conn_req.protocol = CAIFPROTO_DATAGRAM;
priv->conn_req.link_selector = CAIF_LINK_HIGH_BANDW;
priv->conn_req.priority = CAIF_PRIO_LOW;
/* Insert illegal value */
priv->conn_req.sockaddr.u.dgm.connection_id = UNDEF_CONNID;
priv->flowenabled = false;
init_waitqueue_head(&priv->netmgmt_wq);
}
static int ipcaif_fill_info(struct sk_buff *skb, const struct net_device *dev)
{
struct chnl_net *priv;
u8 loop;
priv = netdev_priv(dev);
if (nla_put_u32(skb, IFLA_CAIF_IPV4_CONNID,
priv->conn_req.sockaddr.u.dgm.connection_id) ||
nla_put_u32(skb, IFLA_CAIF_IPV6_CONNID,
priv->conn_req.sockaddr.u.dgm.connection_id))
goto nla_put_failure;
loop = priv->conn_req.protocol == CAIFPROTO_DATAGRAM_LOOP;
if (nla_put_u8(skb, IFLA_CAIF_LOOPBACK, loop))
goto nla_put_failure;
return 0;
nla_put_failure:
return -EMSGSIZE;
}
static void caif_netlink_parms(struct nlattr *data[],
struct caif_connect_request *conn_req)
{
if (!data) {
pr_warn("no params data found\n");
return;
}
if (data[IFLA_CAIF_IPV4_CONNID])
conn_req->sockaddr.u.dgm.connection_id =
nla_get_u32(data[IFLA_CAIF_IPV4_CONNID]);
if (data[IFLA_CAIF_IPV6_CONNID])
conn_req->sockaddr.u.dgm.connection_id =
nla_get_u32(data[IFLA_CAIF_IPV6_CONNID]);
if (data[IFLA_CAIF_LOOPBACK]) {
if (nla_get_u8(data[IFLA_CAIF_LOOPBACK]))
conn_req->protocol = CAIFPROTO_DATAGRAM_LOOP;
else
conn_req->protocol = CAIFPROTO_DATAGRAM;
}
}
static int ipcaif_newlink(struct net *src_net, struct net_device *dev,
struct nlattr *tb[], struct nlattr *data[])
{
int ret;
struct chnl_net *caifdev;
ASSERT_RTNL();
caifdev = netdev_priv(dev);
caif_netlink_parms(data, &caifdev->conn_req);
ret = register_netdevice(dev);
if (ret)
pr_warn("device rtml registration failed\n");
else
list_add(&caifdev->list_field, &chnl_net_list);
/* Use ifindex as connection id, and use loopback channel default. */
if (caifdev->conn_req.sockaddr.u.dgm.connection_id == UNDEF_CONNID) {
caifdev->conn_req.sockaddr.u.dgm.connection_id = dev->ifindex;
caifdev->conn_req.protocol = CAIFPROTO_DATAGRAM_LOOP;
}
return ret;
}
static int ipcaif_changelink(struct net_device *dev, struct nlattr *tb[],
struct nlattr *data[])
{
struct chnl_net *caifdev;
ASSERT_RTNL();
caifdev = netdev_priv(dev);
caif_netlink_parms(data, &caifdev->conn_req);
netdev_state_change(dev);
return 0;
}
static size_t ipcaif_get_size(const struct net_device *dev)
{
return
/* IFLA_CAIF_IPV4_CONNID */
nla_total_size(4) +
/* IFLA_CAIF_IPV6_CONNID */
nla_total_size(4) +
/* IFLA_CAIF_LOOPBACK */
nla_total_size(2) +
0;
}
static const struct nla_policy ipcaif_policy[IFLA_CAIF_MAX + 1] = {
[IFLA_CAIF_IPV4_CONNID] = { .type = NLA_U32 },
[IFLA_CAIF_IPV6_CONNID] = { .type = NLA_U32 },
[IFLA_CAIF_LOOPBACK] = { .type = NLA_U8 }
};
static struct rtnl_link_ops ipcaif_link_ops __read_mostly = {
.kind = "caif",
.priv_size = sizeof(struct chnl_net),
.setup = ipcaif_net_setup,
.maxtype = IFLA_CAIF_MAX,
.policy = ipcaif_policy,
.newlink = ipcaif_newlink,
.changelink = ipcaif_changelink,
.get_size = ipcaif_get_size,
.fill_info = ipcaif_fill_info,
};
static int __init chnl_init_module(void)
{
return rtnl_link_register(&ipcaif_link_ops);
}
static void __exit chnl_exit_module(void)
{
struct chnl_net *dev = NULL;
struct list_head *list_node;
struct list_head *_tmp;
rtnl_link_unregister(&ipcaif_link_ops);
rtnl_lock();
list_for_each_safe(list_node, _tmp, &chnl_net_list) {
dev = list_entry(list_node, struct chnl_net, list_field);
list_del(list_node);
delete_device(dev);
}
rtnl_unlock();
}
module_init(chnl_init_module);
module_exit(chnl_exit_module);