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linux/drivers/isdn/i4l/isdn_x25iface.c
Johannes Berg 634fef6107 networking: add and use skb_put_u8() 
Joe and Bjørn suggested that it'd be nicer to not have the
cast in the fairly common case of doing
	*(u8 *)skb_put(skb, 1) = c;

Add skb_put_u8() for this case, and use it across the code,
using the following spatch:

    @@
    expression SKB, C, S;
    typedef u8;
    identifier fn = {skb_put};
    fresh identifier fn2 = fn ## "_u8";
    @@
    - *(u8 *)fn(SKB, S) = C;
    + fn2(SKB, C);

Note that due to the "S", the spatch isn't perfect, it should
have checked that S is 1, but there's also places that use a
sizeof expression like sizeof(var) or sizeof(u8) etc. Turns
out that nobody ever did something like
	*(u8 *)skb_put(skb, 2) = c;

which would be wrong anyway since the second byte wouldn't be
initialized.

Suggested-by: Joe Perches <joe@perches.com>
Suggested-by: Bjørn Mork <bjorn@mork.no>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2017-06-16 11:48:40 -04:00

333 lines
9.8 KiB
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/* $Id: isdn_x25iface.c,v 1.1.2.2 2004/01/12 22:37:19 keil Exp $
*
* Linux ISDN subsystem, X.25 related functions
*
* This software may be used and distributed according to the terms
* of the GNU General Public License, incorporated herein by reference.
*
* stuff needed to support the Linux X.25 PLP code on top of devices that
* can provide a lab_b service using the concap_proto mechanism.
* This module supports a network interface which provides lapb_sematics
* -- as defined in Documentation/networking/x25-iface.txt -- to
* the upper layer and assumes that the lower layer provides a reliable
* data link service by means of the concap_device_ops callbacks.
*
* Only protocol specific stuff goes here. Device specific stuff
* goes to another -- device related -- concap_proto support source file.
*
*/
/* #include <linux/isdn.h> */
#include <linux/netdevice.h>
#include <linux/concap.h>
#include <linux/slab.h>
#include <linux/wanrouter.h>
#include <net/x25device.h>
#include "isdn_x25iface.h"
/* for debugging messages not to cause an oops when device pointer is NULL*/
#define MY_DEVNAME(dev) ((dev) ? (dev)->name : "DEVICE UNSPECIFIED")
typedef struct isdn_x25iface_proto_data {
int magic;
enum wan_states state;
/* Private stuff, not to be accessed via proto_data. We provide the
other storage for the concap_proto instance here as well,
enabling us to allocate both with just one kmalloc(): */
struct concap_proto priv;
} ix25_pdata_t;
/* is now in header file (extern): struct concap_proto * isdn_x25iface_proto_new(void); */
static void isdn_x25iface_proto_del(struct concap_proto *);
static int isdn_x25iface_proto_close(struct concap_proto *);
static int isdn_x25iface_proto_restart(struct concap_proto *,
struct net_device *,
struct concap_device_ops *);
static int isdn_x25iface_xmit(struct concap_proto *, struct sk_buff *);
static int isdn_x25iface_receive(struct concap_proto *, struct sk_buff *);
static int isdn_x25iface_connect_ind(struct concap_proto *);
static int isdn_x25iface_disconn_ind(struct concap_proto *);
static struct concap_proto_ops ix25_pops = {
.proto_new = &isdn_x25iface_proto_new,
.proto_del = &isdn_x25iface_proto_del,
.restart = &isdn_x25iface_proto_restart,
.close = &isdn_x25iface_proto_close,
.encap_and_xmit = &isdn_x25iface_xmit,
.data_ind = &isdn_x25iface_receive,
.connect_ind = &isdn_x25iface_connect_ind,
.disconn_ind = &isdn_x25iface_disconn_ind
};
/* error message helper function */
static void illegal_state_warn(unsigned state, unsigned char firstbyte)
{
printk(KERN_WARNING "isdn_x25iface: firstbyte %x illegal in"
"current state %d\n", firstbyte, state);
}
/* check protocol data field for consistency */
static int pdata_is_bad(ix25_pdata_t *pda) {
if (pda && pda->magic == ISDN_X25IFACE_MAGIC) return 0;
printk(KERN_WARNING
"isdn_x25iface_xxx: illegal pointer to proto data\n");
return 1;
}
/* create a new x25 interface protocol instance
*/
struct concap_proto *isdn_x25iface_proto_new(void)
{
ix25_pdata_t *tmp = kmalloc(sizeof(ix25_pdata_t), GFP_KERNEL);
IX25DEBUG("isdn_x25iface_proto_new\n");
if (tmp) {
tmp->magic = ISDN_X25IFACE_MAGIC;
tmp->state = WAN_UNCONFIGURED;
/* private data space used to hold the concap_proto data.
Only to be accessed via the returned pointer */
spin_lock_init(&tmp->priv.lock);
tmp->priv.dops = NULL;
tmp->priv.net_dev = NULL;
tmp->priv.pops = &ix25_pops;
tmp->priv.flags = 0;
tmp->priv.proto_data = tmp;
return (&(tmp->priv));
}
return NULL;
};
/* close the x25iface encapsulation protocol
*/
static int isdn_x25iface_proto_close(struct concap_proto *cprot) {
ix25_pdata_t *tmp;
int ret = 0;
ulong flags;
if (!cprot) {
printk(KERN_ERR "isdn_x25iface_proto_close: "
"invalid concap_proto pointer\n");
return -1;
}
IX25DEBUG("isdn_x25iface_proto_close %s \n", MY_DEVNAME(cprot->net_dev));
spin_lock_irqsave(&cprot->lock, flags);
cprot->dops = NULL;
cprot->net_dev = NULL;
tmp = cprot->proto_data;
if (pdata_is_bad(tmp)) {
ret = -1;
} else {
tmp->state = WAN_UNCONFIGURED;
}
spin_unlock_irqrestore(&cprot->lock, flags);
return ret;
}
/* Delete the x25iface encapsulation protocol instance
*/
static void isdn_x25iface_proto_del(struct concap_proto *cprot) {
ix25_pdata_t *tmp;
IX25DEBUG("isdn_x25iface_proto_del \n");
if (!cprot) {
printk(KERN_ERR "isdn_x25iface_proto_del: "
"concap_proto pointer is NULL\n");
return;
}
tmp = cprot->proto_data;
if (tmp == NULL) {
printk(KERN_ERR "isdn_x25iface_proto_del: inconsistent "
"proto_data pointer (maybe already deleted?)\n");
return;
}
/* close if the protocol is still open */
if (cprot->dops) isdn_x25iface_proto_close(cprot);
/* freeing the storage should be sufficient now. But some additional
settings might help to catch wild pointer bugs */
tmp->magic = 0;
cprot->proto_data = NULL;
kfree(tmp);
return;
}
/* (re-)initialize the data structures for x25iface encapsulation
*/
static int isdn_x25iface_proto_restart(struct concap_proto *cprot,
struct net_device *ndev,
struct concap_device_ops *dops)
{
ix25_pdata_t *pda = cprot->proto_data;
ulong flags;
IX25DEBUG("isdn_x25iface_proto_restart %s \n", MY_DEVNAME(ndev));
if (pdata_is_bad(pda)) return -1;
if (!(dops && dops->data_req && dops->connect_req
&& dops->disconn_req)) {
printk(KERN_WARNING "isdn_x25iface_restart: required dops"
" missing\n");
isdn_x25iface_proto_close(cprot);
return -1;
}
spin_lock_irqsave(&cprot->lock, flags);
cprot->net_dev = ndev;
cprot->pops = &ix25_pops;
cprot->dops = dops;
pda->state = WAN_DISCONNECTED;
spin_unlock_irqrestore(&cprot->lock, flags);
return 0;
}
/* deliver a dl_data frame received from i4l HL driver to the network layer
*/
static int isdn_x25iface_receive(struct concap_proto *cprot, struct sk_buff *skb)
{
IX25DEBUG("isdn_x25iface_receive %s \n", MY_DEVNAME(cprot->net_dev));
if (((ix25_pdata_t *)(cprot->proto_data))
->state == WAN_CONNECTED) {
if (skb_push(skb, 1)) {
skb->data[0] = X25_IFACE_DATA;
skb->protocol = x25_type_trans(skb, cprot->net_dev);
netif_rx(skb);
return 0;
}
}
printk(KERN_WARNING "isdn_x25iface_receive %s: not connected, skb dropped\n", MY_DEVNAME(cprot->net_dev));
dev_kfree_skb(skb);
return -1;
}
/* a connection set up is indicated by lower layer
*/
static int isdn_x25iface_connect_ind(struct concap_proto *cprot)
{
struct sk_buff *skb;
enum wan_states *state_p
= &(((ix25_pdata_t *)(cprot->proto_data))->state);
IX25DEBUG("isdn_x25iface_connect_ind %s \n"
, MY_DEVNAME(cprot->net_dev));
if (*state_p == WAN_UNCONFIGURED) {
printk(KERN_WARNING
"isdn_x25iface_connect_ind while unconfigured %s\n"
, MY_DEVNAME(cprot->net_dev));
return -1;
}
*state_p = WAN_CONNECTED;
skb = dev_alloc_skb(1);
if (skb) {
skb_put_u8(skb, X25_IFACE_CONNECT);
skb->protocol = x25_type_trans(skb, cprot->net_dev);
netif_rx(skb);
return 0;
} else {
printk(KERN_WARNING "isdn_x25iface_connect_ind: "
" out of memory -- disconnecting\n");
cprot->dops->disconn_req(cprot);
return -1;
}
}
/* a disconnect is indicated by lower layer
*/
static int isdn_x25iface_disconn_ind(struct concap_proto *cprot)
{
struct sk_buff *skb;
enum wan_states *state_p
= &(((ix25_pdata_t *)(cprot->proto_data))->state);
IX25DEBUG("isdn_x25iface_disconn_ind %s \n", MY_DEVNAME(cprot->net_dev));
if (*state_p == WAN_UNCONFIGURED) {
printk(KERN_WARNING
"isdn_x25iface_disconn_ind while unconfigured\n");
return -1;
}
if (!cprot->net_dev) return -1;
*state_p = WAN_DISCONNECTED;
skb = dev_alloc_skb(1);
if (skb) {
skb_put_u8(skb, X25_IFACE_DISCONNECT);
skb->protocol = x25_type_trans(skb, cprot->net_dev);
netif_rx(skb);
return 0;
} else {
printk(KERN_WARNING "isdn_x25iface_disconn_ind:"
" out of memory\n");
return -1;
}
}
/* process a frame handed over to us from linux network layer. First byte
semantics as defined in Documentation/networking/x25-iface.txt
*/
static int isdn_x25iface_xmit(struct concap_proto *cprot, struct sk_buff *skb)
{
unsigned char firstbyte = skb->data[0];
enum wan_states *state = &((ix25_pdata_t *)cprot->proto_data)->state;
int ret = 0;
IX25DEBUG("isdn_x25iface_xmit: %s first=%x state=%d\n",
MY_DEVNAME(cprot->net_dev), firstbyte, *state);
switch (firstbyte) {
case X25_IFACE_DATA:
if (*state == WAN_CONNECTED) {
skb_pull(skb, 1);
netif_trans_update(cprot->net_dev);
ret = (cprot->dops->data_req(cprot, skb));
/* prepare for future retransmissions */
if (ret) skb_push(skb, 1);
return ret;
}
illegal_state_warn(*state, firstbyte);
break;
case X25_IFACE_CONNECT:
if (*state == WAN_DISCONNECTED) {
*state = WAN_CONNECTING;
ret = cprot->dops->connect_req(cprot);
if (ret) {
/* reset state and notify upper layer about
* immidiatly failed attempts */
isdn_x25iface_disconn_ind(cprot);
}
} else {
illegal_state_warn(*state, firstbyte);
}
break;
case X25_IFACE_DISCONNECT:
switch (*state) {
case WAN_DISCONNECTED:
/* Should not happen. However, give upper layer a
chance to recover from inconstistency but don't
trust the lower layer sending the disconn_confirm
when already disconnected */
printk(KERN_WARNING "isdn_x25iface_xmit: disconnect "
" requested while disconnected\n");
isdn_x25iface_disconn_ind(cprot);
break; /* prevent infinite loops */
case WAN_CONNECTING:
case WAN_CONNECTED:
*state = WAN_DISCONNECTED;
cprot->dops->disconn_req(cprot);
break;
default:
illegal_state_warn(*state, firstbyte);
}
break;
case X25_IFACE_PARAMS:
printk(KERN_WARNING "isdn_x25iface_xmit: setting of lapb"
" options not yet supported\n");
break;
default:
printk(KERN_WARNING "isdn_x25iface_xmit: frame with illegal"
" first byte %x ignored:\n", firstbyte);
}
dev_kfree_skb(skb);
return 0;
}
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