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linux/drivers/net/pppoe.c
Michal Ostrowski fb64bb560e PPPoE: Fix flush/close races. 
Be more careful about the state of pointers during tear-down.
The "pppoe_dev" field can only be looked at safely while holding socket locks.
This subsequently allows for the flush_lock to be killed.

We depend on the PPPOX_CONNECTED state to tell us that that those fields are
valid, so whoever clears that state (pppox_unbind_sock()) is responsible for
the dev_put() call.

We also have to ensure that we delete_item() on all sockets before they are
cleaned up.

The need for these changes has been exposed by scenarios wherein namespace
bindings of ethernet devices change while there are ongoing PPPoE sessions,
which resulted in oopses due to unusual socket connection termination paths,
exposing these issues.

Signed-off-by: Michal Ostrowski <mostrows@gmail.com>
Reviewed-by: Cyril Gorcunov <gorcunov@gmail.com>
Reported-by: Denys Fedoryschenko <denys@visp.net.lb>
Tested-by: Denys Fedoryschenko <denys@visp.net.lb>
2009-10-26 16:23:20 -07:00

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/** -*- linux-c -*- ***********************************************************
* Linux PPP over Ethernet (PPPoX/PPPoE) Sockets
*
* PPPoX --- Generic PPP encapsulation socket family
* PPPoE --- PPP over Ethernet (RFC 2516)
*
*
* Version: 0.7.0
*
* 070228 : Fix to allow multiple sessions with same remote MAC and same
* session id by including the local device ifindex in the
* tuple identifying a session. This also ensures packets can't
* be injected into a session from interfaces other than the one
* specified by userspace. Florian Zumbiehl <florz@florz.de>
* (Oh, BTW, this one is YYMMDD, in case you were wondering ...)
* 220102 : Fix module use count on failure in pppoe_create, pppox_sk -acme
* 030700 : Fixed connect logic to allow for disconnect.
* 270700 : Fixed potential SMP problems; we must protect against
* simultaneous invocation of ppp_input
* and ppp_unregister_channel.
* 040800 : Respect reference count mechanisms on net-devices.
* 200800 : fix kfree(skb) in pppoe_rcv (acme)
* Module reference count is decremented in the right spot now,
* guards against sock_put not actually freeing the sk
* in pppoe_release.
* 051000 : Initialization cleanup.
* 111100 : Fix recvmsg.
* 050101 : Fix PADT procesing.
* 140501 : Use pppoe_rcv_core to handle all backlog. (Alexey)
* 170701 : Do not lock_sock with rwlock held. (DaveM)
* Ignore discovery frames if user has socket
* locked. (DaveM)
* Ignore return value of dev_queue_xmit in __pppoe_xmit
* or else we may kfree an SKB twice. (DaveM)
* 190701 : When doing copies of skb's in __pppoe_xmit, always delete
* the original skb that was passed in on success, never on
* failure. Delete the copy of the skb on failure to avoid
* a memory leak.
* 081001 : Misc. cleanup (licence string, non-blocking, prevent
* reference of device on close).
* 121301 : New ppp channels interface; cannot unregister a channel
* from interrupts. Thus, we mark the socket as a ZOMBIE
* and do the unregistration later.
* 081002 : seq_file support for proc stuff -acme
* 111602 : Merge all 2.4 fixes into 2.5/2.6 tree. Label 2.5/2.6
* as version 0.7. Spacing cleanup.
* Author: Michal Ostrowski <mostrows@speakeasy.net>
* Contributors:
* Arnaldo Carvalho de Melo <acme@conectiva.com.br>
* David S. Miller (davem@redhat.com)
*
* License:
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version
* 2 of the License, or (at your option) any later version.
*
*/
#include <linux/string.h>
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/slab.h>
#include <linux/errno.h>
#include <linux/netdevice.h>
#include <linux/net.h>
#include <linux/inetdevice.h>
#include <linux/etherdevice.h>
#include <linux/skbuff.h>
#include <linux/init.h>
#include <linux/if_ether.h>
#include <linux/if_pppox.h>
#include <linux/ppp_channel.h>
#include <linux/ppp_defs.h>
#include <linux/if_ppp.h>
#include <linux/notifier.h>
#include <linux/file.h>
#include <linux/proc_fs.h>
#include <linux/seq_file.h>
#include <linux/nsproxy.h>
#include <net/net_namespace.h>
#include <net/netns/generic.h>
#include <net/sock.h>
#include <asm/uaccess.h>
#define PPPOE_HASH_BITS 4
#define PPPOE_HASH_SIZE (1 << PPPOE_HASH_BITS)
#define PPPOE_HASH_MASK (PPPOE_HASH_SIZE - 1)
static int pppoe_ioctl(struct socket *sock, unsigned int cmd, unsigned long arg);
static int pppoe_xmit(struct ppp_channel *chan, struct sk_buff *skb);
static int __pppoe_xmit(struct sock *sk, struct sk_buff *skb);
static const struct proto_ops pppoe_ops;
static struct ppp_channel_ops pppoe_chan_ops;
/* per-net private data for this module */
static int pppoe_net_id;
struct pppoe_net {
/*
* we could use _single_ hash table for all
* nets by injecting net id into the hash but
* it would increase hash chains and add
* a few additional math comparations messy
* as well, moreover in case of SMP less locking
* controversy here
*/
struct pppox_sock *hash_table[PPPOE_HASH_SIZE];
rwlock_t hash_lock;
};
/*
* PPPoE could be in the following stages:
* 1) Discovery stage (to obtain remote MAC and Session ID)
* 2) Session stage (MAC and SID are known)
*
* Ethernet frames have a special tag for this but
* we use simplier approach based on session id
*/
static inline bool stage_session(__be16 sid)
{
return sid != 0;
}
static inline struct pppoe_net *pppoe_pernet(struct net *net)
{
BUG_ON(!net);
return net_generic(net, pppoe_net_id);
}
static inline int cmp_2_addr(struct pppoe_addr *a, struct pppoe_addr *b)
{
return a->sid == b->sid && !memcmp(a->remote, b->remote, ETH_ALEN);
}
static inline int cmp_addr(struct pppoe_addr *a, __be16 sid, char *addr)
{
return a->sid == sid && !memcmp(a->remote, addr, ETH_ALEN);
}
#if 8 % PPPOE_HASH_BITS
#error 8 must be a multiple of PPPOE_HASH_BITS
#endif
static int hash_item(__be16 sid, unsigned char *addr)
{
unsigned char hash = 0;
unsigned int i;
for (i = 0; i < ETH_ALEN; i++)
hash ^= addr[i];
for (i = 0; i < sizeof(sid_t) * 8; i += 8)
hash ^= (__force __u32)sid >> i;
for (i = 8; (i >>= 1) >= PPPOE_HASH_BITS;)
hash ^= hash >> i;
return hash & PPPOE_HASH_MASK;
}
/**********************************************************************
*
* Set/get/delete/rehash items (internal versions)
*
**********************************************************************/
static struct pppox_sock *__get_item(struct pppoe_net *pn, __be16 sid,
unsigned char *addr, int ifindex)
{
int hash = hash_item(sid, addr);
struct pppox_sock *ret;
ret = pn->hash_table[hash];
while (ret) {
if (cmp_addr(&ret->pppoe_pa, sid, addr) &&
ret->pppoe_ifindex == ifindex)
return ret;
ret = ret->next;
}
return NULL;
}
static int __set_item(struct pppoe_net *pn, struct pppox_sock *po)
{
int hash = hash_item(po->pppoe_pa.sid, po->pppoe_pa.remote);
struct pppox_sock *ret;
ret = pn->hash_table[hash];
while (ret) {
if (cmp_2_addr(&ret->pppoe_pa, &po->pppoe_pa) &&
ret->pppoe_ifindex == po->pppoe_ifindex)
return -EALREADY;
ret = ret->next;
}
po->next = pn->hash_table[hash];
pn->hash_table[hash] = po;
return 0;
}
static struct pppox_sock *__delete_item(struct pppoe_net *pn, __be16 sid,
char *addr, int ifindex)
{
int hash = hash_item(sid, addr);
struct pppox_sock *ret, **src;
ret = pn->hash_table[hash];
src = &pn->hash_table[hash];
while (ret) {
if (cmp_addr(&ret->pppoe_pa, sid, addr) &&
ret->pppoe_ifindex == ifindex) {
*src = ret->next;
break;
}
src = &ret->next;
ret = ret->next;
}
return ret;
}
/**********************************************************************
*
* Set/get/delete/rehash items
*
**********************************************************************/
static inline struct pppox_sock *get_item(struct pppoe_net *pn, __be16 sid,
unsigned char *addr, int ifindex)
{
struct pppox_sock *po;
read_lock_bh(&pn->hash_lock);
po = __get_item(pn, sid, addr, ifindex);
if (po)
sock_hold(sk_pppox(po));
read_unlock_bh(&pn->hash_lock);
return po;
}
static inline struct pppox_sock *get_item_by_addr(struct net *net,
struct sockaddr_pppox *sp)
{
struct net_device *dev;
struct pppoe_net *pn;
struct pppox_sock *pppox_sock;
int ifindex;
dev = dev_get_by_name(net, sp->sa_addr.pppoe.dev);
if (!dev)
return NULL;
ifindex = dev->ifindex;
pn = net_generic(net, pppoe_net_id);
pppox_sock = get_item(pn, sp->sa_addr.pppoe.sid,
sp->sa_addr.pppoe.remote, ifindex);
dev_put(dev);
return pppox_sock;
}
static inline struct pppox_sock *delete_item(struct pppoe_net *pn, __be16 sid,
char *addr, int ifindex)
{
struct pppox_sock *ret;
write_lock_bh(&pn->hash_lock);
ret = __delete_item(pn, sid, addr, ifindex);
write_unlock_bh(&pn->hash_lock);
return ret;
}
/***************************************************************************
*
* Handler for device events.
* Certain device events require that sockets be unconnected.
*
**************************************************************************/
static void pppoe_flush_dev(struct net_device *dev)
{
struct pppoe_net *pn;
int i;
BUG_ON(dev == NULL);
pn = pppoe_pernet(dev_net(dev));
if (!pn) /* already freed */
return;
write_lock_bh(&pn->hash_lock);
for (i = 0; i < PPPOE_HASH_SIZE; i++) {
struct pppox_sock *po = pn->hash_table[i];
struct sock *sk;
while (po) {
while (po && po->pppoe_dev != dev) {
po = po->next;
}
if (!po)
break;
sk = sk_pppox(po);
/* We always grab the socket lock, followed by the
* hash_lock, in that order. Since we should hold the
* sock lock while doing any unbinding, we need to
* release the lock we're holding. Hold a reference to
* the sock so it doesn't disappear as we're jumping
* between locks.
*/
sock_hold(sk);
write_unlock_bh(&pn->hash_lock);
lock_sock(sk);
if (po->pppoe_dev == dev
&& sk->sk_state & (PPPOX_CONNECTED | PPPOX_BOUND)) {
pppox_unbind_sock(sk);
sk->sk_state = PPPOX_ZOMBIE;
sk->sk_state_change(sk);
po->pppoe_dev = NULL;
dev_put(dev);
}
release_sock(sk);
sock_put(sk);
/* Restart the process from the start of the current
* hash chain. We dropped locks so the world may have
* change from underneath us.
*/
BUG_ON(pppoe_pernet(dev_net(dev)) == NULL);
write_lock_bh(&pn->hash_lock);
po = pn->hash_table[i];
}
}
write_unlock_bh(&pn->hash_lock);
}
static int pppoe_device_event(struct notifier_block *this,
unsigned long event, void *ptr)
{
struct net_device *dev = (struct net_device *)ptr;
/* Only look at sockets that are using this specific device. */
switch (event) {
case NETDEV_CHANGEMTU:
/* A change in mtu is a bad thing, requiring
* LCP re-negotiation.
*/
case NETDEV_GOING_DOWN:
case NETDEV_DOWN:
/* Find every socket on this device and kill it. */
pppoe_flush_dev(dev);
break;
default:
break;
};
return NOTIFY_DONE;
}
static struct notifier_block pppoe_notifier = {
.notifier_call = pppoe_device_event,
};
/************************************************************************
*
* Do the real work of receiving a PPPoE Session frame.
*
***********************************************************************/
static int pppoe_rcv_core(struct sock *sk, struct sk_buff *skb)
{
struct pppox_sock *po = pppox_sk(sk);
struct pppox_sock *relay_po;
/* Backlog receive. Semantics of backlog rcv preclude any code from
* executing in lock_sock()/release_sock() bounds; meaning sk->sk_state
* can't change.
*/
if (sk->sk_state & PPPOX_BOUND) {
ppp_input(&po->chan, skb);
} else if (sk->sk_state & PPPOX_RELAY) {
relay_po = get_item_by_addr(sock_net(sk),
&po->pppoe_relay);
if (relay_po == NULL)
goto abort_kfree;
if ((sk_pppox(relay_po)->sk_state & PPPOX_CONNECTED) == 0)
goto abort_put;
if (!__pppoe_xmit(sk_pppox(relay_po), skb))
goto abort_put;
} else {
if (sock_queue_rcv_skb(sk, skb))
goto abort_kfree;
}
return NET_RX_SUCCESS;
abort_put:
sock_put(sk_pppox(relay_po));
abort_kfree:
kfree_skb(skb);
return NET_RX_DROP;
}
/************************************************************************
*
* Receive wrapper called in BH context.
*
***********************************************************************/
static int pppoe_rcv(struct sk_buff *skb, struct net_device *dev,
struct packet_type *pt, struct net_device *orig_dev)
{
struct pppoe_hdr *ph;
struct pppox_sock *po;
struct pppoe_net *pn;
int len;
skb = skb_share_check(skb, GFP_ATOMIC);
if (!skb)
goto out;
if (!pskb_may_pull(skb, sizeof(struct pppoe_hdr)))
goto drop;
ph = pppoe_hdr(skb);
len = ntohs(ph->length);
skb_pull_rcsum(skb, sizeof(*ph));
if (skb->len < len)
goto drop;
if (pskb_trim_rcsum(skb, len))
goto drop;
pn = pppoe_pernet(dev_net(dev));
/* Note that get_item does a sock_hold(), so sk_pppox(po)
* is known to be safe.
*/
po = get_item(pn, ph->sid, eth_hdr(skb)->h_source, dev->ifindex);
if (!po)
goto drop;
return sk_receive_skb(sk_pppox(po), skb, 0);
drop:
kfree_skb(skb);
out:
return NET_RX_DROP;
}
/************************************************************************
*
* Receive a PPPoE Discovery frame.
* This is solely for detection of PADT frames
*
***********************************************************************/
static int pppoe_disc_rcv(struct sk_buff *skb, struct net_device *dev,
struct packet_type *pt, struct net_device *orig_dev)
{
struct pppoe_hdr *ph;
struct pppox_sock *po;
struct pppoe_net *pn;
skb = skb_share_check(skb, GFP_ATOMIC);
if (!skb)
goto out;
if (!pskb_may_pull(skb, sizeof(struct pppoe_hdr)))
goto abort;
ph = pppoe_hdr(skb);
if (ph->code != PADT_CODE)
goto abort;
pn = pppoe_pernet(dev_net(dev));
po = get_item(pn, ph->sid, eth_hdr(skb)->h_source, dev->ifindex);
if (po) {
struct sock *sk = sk_pppox(po);
bh_lock_sock(sk);
/* If the user has locked the socket, just ignore
* the packet. With the way two rcv protocols hook into
* one socket family type, we cannot (easily) distinguish
* what kind of SKB it is during backlog rcv.
*/
if (sock_owned_by_user(sk) == 0) {
/* We're no longer connect at the PPPOE layer,
* and must wait for ppp channel to disconnect us.
*/
sk->sk_state = PPPOX_ZOMBIE;
}
bh_unlock_sock(sk);
sock_put(sk);
}
abort:
kfree_skb(skb);
out:
return NET_RX_SUCCESS; /* Lies... :-) */
}
static struct packet_type pppoes_ptype __read_mostly = {
.type = cpu_to_be16(ETH_P_PPP_SES),
.func = pppoe_rcv,
};
static struct packet_type pppoed_ptype __read_mostly = {
.type = cpu_to_be16(ETH_P_PPP_DISC),
.func = pppoe_disc_rcv,
};
static struct proto pppoe_sk_proto __read_mostly = {
.name = "PPPOE",
.owner = THIS_MODULE,
.obj_size = sizeof(struct pppox_sock),
};
/***********************************************************************
*
* Initialize a new struct sock.
*
**********************************************************************/
static int pppoe_create(struct net *net, struct socket *sock)
{
struct sock *sk;
sk = sk_alloc(net, PF_PPPOX, GFP_KERNEL, &pppoe_sk_proto);
if (!sk)
return -ENOMEM;
sock_init_data(sock, sk);
sock->state = SS_UNCONNECTED;
sock->ops = &pppoe_ops;
sk->sk_backlog_rcv = pppoe_rcv_core;
sk->sk_state = PPPOX_NONE;
sk->sk_type = SOCK_STREAM;
sk->sk_family = PF_PPPOX;
sk->sk_protocol = PX_PROTO_OE;
return 0;
}
static int pppoe_release(struct socket *sock)
{
struct sock *sk = sock->sk;
struct pppox_sock *po;
struct pppoe_net *pn;
struct net *net = NULL;
if (!sk)
return 0;
lock_sock(sk);
if (sock_flag(sk, SOCK_DEAD)) {
release_sock(sk);
return -EBADF;
}
po = pppox_sk(sk);
if (sk->sk_state & (PPPOX_CONNECTED | PPPOX_BOUND)) {
dev_put(po->pppoe_dev);
po->pppoe_dev = NULL;
}
pppox_unbind_sock(sk);
/* Signal the death of the socket. */
sk->sk_state = PPPOX_DEAD;
net = sock_net(sk);
pn = pppoe_pernet(net);
/*
* protect "po" from concurrent updates
* on pppoe_flush_dev
*/
delete_item(pn, po->pppoe_pa.sid, po->pppoe_pa.remote,
po->pppoe_ifindex);
sock_orphan(sk);
sock->sk = NULL;
skb_queue_purge(&sk->sk_receive_queue);
release_sock(sk);
sock_put(sk);
return 0;
}
static int pppoe_connect(struct socket *sock, struct sockaddr *uservaddr,
int sockaddr_len, int flags)
{
struct sock *sk = sock->sk;
struct sockaddr_pppox *sp = (struct sockaddr_pppox *)uservaddr;
struct pppox_sock *po = pppox_sk(sk);
struct net_device *dev = NULL;
struct pppoe_net *pn;
struct net *net = NULL;
int error;
lock_sock(sk);
error = -EINVAL;
if (sp->sa_protocol != PX_PROTO_OE)
goto end;
/* Check for already bound sockets */
error = -EBUSY;
if ((sk->sk_state & PPPOX_CONNECTED) &&
stage_session(sp->sa_addr.pppoe.sid))
goto end;
/* Check for already disconnected sockets, on attempts to disconnect */
error = -EALREADY;
if ((sk->sk_state & PPPOX_DEAD) &&
!stage_session(sp->sa_addr.pppoe.sid))
goto end;
error = 0;
/* Delete the old binding */
if (stage_session(po->pppoe_pa.sid)) {
pppox_unbind_sock(sk);
pn = pppoe_pernet(sock_net(sk));
delete_item(pn, po->pppoe_pa.sid,
po->pppoe_pa.remote, po->pppoe_ifindex);
if (po->pppoe_dev) {
dev_put(po->pppoe_dev);
po->pppoe_dev = NULL;
}
memset(sk_pppox(po) + 1, 0,
sizeof(struct pppox_sock) - sizeof(struct sock));
sk->sk_state = PPPOX_NONE;
}
/* Re-bind in session stage only */
if (stage_session(sp->sa_addr.pppoe.sid)) {
error = -ENODEV;
net = sock_net(sk);
dev = dev_get_by_name(net, sp->sa_addr.pppoe.dev);
if (!dev)
goto err_put;
po->pppoe_dev = dev;
po->pppoe_ifindex = dev->ifindex;
pn = pppoe_pernet(net);
if (!(dev->flags & IFF_UP)) {
goto err_put;
}
memcpy(&po->pppoe_pa,
&sp->sa_addr.pppoe,
sizeof(struct pppoe_addr));
write_lock_bh(&pn->hash_lock);
error = __set_item(pn, po);
write_unlock_bh(&pn->hash_lock);
if (error < 0)
goto err_put;
po->chan.hdrlen = (sizeof(struct pppoe_hdr) +
dev->hard_header_len);
po->chan.mtu = dev->mtu - sizeof(struct pppoe_hdr);
po->chan.private = sk;
po->chan.ops = &pppoe_chan_ops;
error = ppp_register_net_channel(dev_net(dev), &po->chan);
if (error) {
delete_item(pn, po->pppoe_pa.sid,
po->pppoe_pa.remote, po->pppoe_ifindex);
goto err_put;
}
sk->sk_state = PPPOX_CONNECTED;
}
po->num = sp->sa_addr.pppoe.sid;
end:
release_sock(sk);
return error;
err_put:
if (po->pppoe_dev) {
dev_put(po->pppoe_dev);
po->pppoe_dev = NULL;
}
goto end;
}
static int pppoe_getname(struct socket *sock, struct sockaddr *uaddr,
int *usockaddr_len, int peer)
{
int len = sizeof(struct sockaddr_pppox);
struct sockaddr_pppox sp;
sp.sa_family = AF_PPPOX;
sp.sa_protocol = PX_PROTO_OE;
memcpy(&sp.sa_addr.pppoe, &pppox_sk(sock->sk)->pppoe_pa,
sizeof(struct pppoe_addr));
memcpy(uaddr, &sp, len);
*usockaddr_len = len;
return 0;
}
static int pppoe_ioctl(struct socket *sock, unsigned int cmd,
unsigned long arg)
{
struct sock *sk = sock->sk;
struct pppox_sock *po = pppox_sk(sk);
int val;
int err;
switch (cmd) {
case PPPIOCGMRU:
err = -ENXIO;
if (!(sk->sk_state & PPPOX_CONNECTED))
break;
err = -EFAULT;
if (put_user(po->pppoe_dev->mtu -
sizeof(struct pppoe_hdr) -
PPP_HDRLEN,
(int __user *)arg))
break;
err = 0;
break;
case PPPIOCSMRU:
err = -ENXIO;
if (!(sk->sk_state & PPPOX_CONNECTED))
break;
err = -EFAULT;
if (get_user(val, (int __user *)arg))
break;
if (val < (po->pppoe_dev->mtu
- sizeof(struct pppoe_hdr)
- PPP_HDRLEN))
err = 0;
else
err = -EINVAL;
break;
case PPPIOCSFLAGS:
err = -EFAULT;
if (get_user(val, (int __user *)arg))
break;
err = 0;
break;
case PPPOEIOCSFWD:
{
struct pppox_sock *relay_po;
err = -EBUSY;
if (sk->sk_state & (PPPOX_BOUND | PPPOX_ZOMBIE | PPPOX_DEAD))
break;
err = -ENOTCONN;
if (!(sk->sk_state & PPPOX_CONNECTED))
break;
/* PPPoE address from the user specifies an outbound
PPPoE address which frames are forwarded to */
err = -EFAULT;
if (copy_from_user(&po->pppoe_relay,
(void __user *)arg,
sizeof(struct sockaddr_pppox)))
break;
err = -EINVAL;
if (po->pppoe_relay.sa_family != AF_PPPOX ||
po->pppoe_relay.sa_protocol != PX_PROTO_OE)
break;
/* Check that the socket referenced by the address
actually exists. */
relay_po = get_item_by_addr(sock_net(sk), &po->pppoe_relay);
if (!relay_po)
break;
sock_put(sk_pppox(relay_po));
sk->sk_state |= PPPOX_RELAY;
err = 0;
break;
}
case PPPOEIOCDFWD:
err = -EALREADY;
if (!(sk->sk_state & PPPOX_RELAY))
break;
sk->sk_state &= ~PPPOX_RELAY;
err = 0;
break;
default:
err = -ENOTTY;
}
return err;
}
static int pppoe_sendmsg(struct kiocb *iocb, struct socket *sock,
struct msghdr *m, size_t total_len)
{
struct sk_buff *skb;
struct sock *sk = sock->sk;
struct pppox_sock *po = pppox_sk(sk);
int error;
struct pppoe_hdr hdr;
struct pppoe_hdr *ph;
struct net_device *dev;
char *start;
lock_sock(sk);
if (sock_flag(sk, SOCK_DEAD) || !(sk->sk_state & PPPOX_CONNECTED)) {
error = -ENOTCONN;
goto end;
}
hdr.ver = 1;
hdr.type = 1;
hdr.code = 0;
hdr.sid = po->num;
dev = po->pppoe_dev;
error = -EMSGSIZE;
if (total_len > (dev->mtu + dev->hard_header_len))
goto end;
skb = sock_wmalloc(sk, total_len + dev->hard_header_len + 32,
0, GFP_KERNEL);
if (!skb) {
error = -ENOMEM;
goto end;
}
/* Reserve space for headers. */
skb_reserve(skb, dev->hard_header_len);
skb_reset_network_header(skb);
skb->dev = dev;
skb->priority = sk->sk_priority;
skb->protocol = cpu_to_be16(ETH_P_PPP_SES);
ph = (struct pppoe_hdr *)skb_put(skb, total_len + sizeof(struct pppoe_hdr));
start = (char *)&ph->tag[0];
error = memcpy_fromiovec(start, m->msg_iov, total_len);
if (error < 0) {
kfree_skb(skb);
goto end;
}
error = total_len;
dev_hard_header(skb, dev, ETH_P_PPP_SES,
po->pppoe_pa.remote, NULL, total_len);
memcpy(ph, &hdr, sizeof(struct pppoe_hdr));
ph->length = htons(total_len);
dev_queue_xmit(skb);
end:
release_sock(sk);
return error;
}
/************************************************************************
*
* xmit function for internal use.
*
***********************************************************************/
static int __pppoe_xmit(struct sock *sk, struct sk_buff *skb)
{
struct pppox_sock *po = pppox_sk(sk);
struct net_device *dev = po->pppoe_dev;
struct pppoe_hdr *ph;
int data_len = skb->len;
/* The higher-level PPP code (ppp_unregister_channel()) ensures the PPP
* xmit operations conclude prior to an unregistration call. Thus
* sk->sk_state cannot change, so we don't need to do lock_sock().
* But, we also can't do a lock_sock since that introduces a potential
* deadlock as we'd reverse the lock ordering used when calling
* ppp_unregister_channel().
*/
if (sock_flag(sk, SOCK_DEAD) || !(sk->sk_state & PPPOX_CONNECTED))
goto abort;
if (!dev)
goto abort;
/* Copy the data if there is no space for the header or if it's
* read-only.
*/
if (skb_cow_head(skb, sizeof(*ph) + dev->hard_header_len))
goto abort;
__skb_push(skb, sizeof(*ph));
skb_reset_network_header(skb);
ph = pppoe_hdr(skb);
ph->ver = 1;
ph->type = 1;
ph->code = 0;
ph->sid = po->num;
ph->length = htons(data_len);
skb->protocol = cpu_to_be16(ETH_P_PPP_SES);
skb->dev = dev;
dev_hard_header(skb, dev, ETH_P_PPP_SES,
po->pppoe_pa.remote, NULL, data_len);
dev_queue_xmit(skb);
return 1;
abort:
kfree_skb(skb);
return 1;
}
/************************************************************************
*
* xmit function called by generic PPP driver
* sends PPP frame over PPPoE socket
*
***********************************************************************/
static int pppoe_xmit(struct ppp_channel *chan, struct sk_buff *skb)
{
struct sock *sk = (struct sock *)chan->private;
return __pppoe_xmit(sk, skb);
}
static struct ppp_channel_ops pppoe_chan_ops = {
.start_xmit = pppoe_xmit,
};
static int pppoe_recvmsg(struct kiocb *iocb, struct socket *sock,
struct msghdr *m, size_t total_len, int flags)
{
struct sock *sk = sock->sk;
struct sk_buff *skb;
int error = 0;
if (sk->sk_state & PPPOX_BOUND) {
error = -EIO;
goto end;
}
skb = skb_recv_datagram(sk, flags & ~MSG_DONTWAIT,
flags & MSG_DONTWAIT, &error);
if (error < 0)
goto end;
m->msg_namelen = 0;
if (skb) {
total_len = min_t(size_t, total_len, skb->len);
error = skb_copy_datagram_iovec(skb, 0, m->msg_iov, total_len);
if (error == 0)
error = total_len;
}
kfree_skb(skb);
end:
return error;
}
#ifdef CONFIG_PROC_FS
static int pppoe_seq_show(struct seq_file *seq, void *v)
{
struct pppox_sock *po;
char *dev_name;
if (v == SEQ_START_TOKEN) {
seq_puts(seq, "Id Address Device\n");
goto out;
}
po = v;
dev_name = po->pppoe_pa.dev;
seq_printf(seq, "%08X %pM %8s\n",
po->pppoe_pa.sid, po->pppoe_pa.remote, dev_name);
out:
return 0;
}
static inline struct pppox_sock *pppoe_get_idx(struct pppoe_net *pn, loff_t pos)
{
struct pppox_sock *po;
int i;
for (i = 0; i < PPPOE_HASH_SIZE; i++) {
po = pn->hash_table[i];
while (po) {
if (!pos--)
goto out;
po = po->next;
}
}
out:
return po;
}
static void *pppoe_seq_start(struct seq_file *seq, loff_t *pos)
__acquires(pn->hash_lock)
{
struct pppoe_net *pn = pppoe_pernet(seq_file_net(seq));
loff_t l = *pos;
read_lock_bh(&pn->hash_lock);
return l ? pppoe_get_idx(pn, --l) : SEQ_START_TOKEN;
}
static void *pppoe_seq_next(struct seq_file *seq, void *v, loff_t *pos)
{
struct pppoe_net *pn = pppoe_pernet(seq_file_net(seq));
struct pppox_sock *po;
++*pos;
if (v == SEQ_START_TOKEN) {
po = pppoe_get_idx(pn, 0);
goto out;
}
po = v;
if (po->next)
po = po->next;
else {
int hash = hash_item(po->pppoe_pa.sid, po->pppoe_pa.remote);
po = NULL;
while (++hash < PPPOE_HASH_SIZE) {
po = pn->hash_table[hash];
if (po)
break;
}
}
out:
return po;
}
static void pppoe_seq_stop(struct seq_file *seq, void *v)
__releases(pn->hash_lock)
{
struct pppoe_net *pn = pppoe_pernet(seq_file_net(seq));
read_unlock_bh(&pn->hash_lock);
}
static const struct seq_operations pppoe_seq_ops = {
.start = pppoe_seq_start,
.next = pppoe_seq_next,
.stop = pppoe_seq_stop,
.show = pppoe_seq_show,
};
static int pppoe_seq_open(struct inode *inode, struct file *file)
{
return seq_open_net(inode, file, &pppoe_seq_ops,
sizeof(struct seq_net_private));
}
static const struct file_operations pppoe_seq_fops = {
.owner = THIS_MODULE,
.open = pppoe_seq_open,
.read = seq_read,
.llseek = seq_lseek,
.release = seq_release_net,
};
#endif /* CONFIG_PROC_FS */
static const struct proto_ops pppoe_ops = {
.family = AF_PPPOX,
.owner = THIS_MODULE,
.release = pppoe_release,
.bind = sock_no_bind,
.connect = pppoe_connect,
.socketpair = sock_no_socketpair,
.accept = sock_no_accept,
.getname = pppoe_getname,
.poll = datagram_poll,
.listen = sock_no_listen,
.shutdown = sock_no_shutdown,
.setsockopt = sock_no_setsockopt,
.getsockopt = sock_no_getsockopt,
.sendmsg = pppoe_sendmsg,
.recvmsg = pppoe_recvmsg,
.mmap = sock_no_mmap,
.ioctl = pppox_ioctl,
};
static struct pppox_proto pppoe_proto = {
.create = pppoe_create,
.ioctl = pppoe_ioctl,
.owner = THIS_MODULE,
};
static __net_init int pppoe_init_net(struct net *net)
{
struct pppoe_net *pn;
struct proc_dir_entry *pde;
int err;
pn = kzalloc(sizeof(*pn), GFP_KERNEL);
if (!pn)
return -ENOMEM;
rwlock_init(&pn->hash_lock);
err = net_assign_generic(net, pppoe_net_id, pn);
if (err)
goto out;
pde = proc_net_fops_create(net, "pppoe", S_IRUGO, &pppoe_seq_fops);
#ifdef CONFIG_PROC_FS
if (!pde) {
err = -ENOMEM;
goto out;
}
#endif
return 0;
out:
kfree(pn);
return err;
}
static __net_exit void pppoe_exit_net(struct net *net)
{
struct pppoe_net *pn;
proc_net_remove(net, "pppoe");
pn = net_generic(net, pppoe_net_id);
/*
* if someone has cached our net then
* further net_generic call will return NULL
*/
net_assign_generic(net, pppoe_net_id, NULL);
kfree(pn);
}
static struct pernet_operations pppoe_net_ops = {
.init = pppoe_init_net,
.exit = pppoe_exit_net,
};
static int __init pppoe_init(void)
{
int err;
err = register_pernet_gen_device(&pppoe_net_id, &pppoe_net_ops);
if (err)
goto out;
err = proto_register(&pppoe_sk_proto, 0);
if (err)
goto out_unregister_net_ops;
err = register_pppox_proto(PX_PROTO_OE, &pppoe_proto);
if (err)
goto out_unregister_pppoe_proto;
dev_add_pack(&pppoes_ptype);
dev_add_pack(&pppoed_ptype);
register_netdevice_notifier(&pppoe_notifier);
return 0;
out_unregister_pppoe_proto:
proto_unregister(&pppoe_sk_proto);
out_unregister_net_ops:
unregister_pernet_gen_device(pppoe_net_id, &pppoe_net_ops);
out:
return err;
}
static void __exit pppoe_exit(void)
{
unregister_netdevice_notifier(&pppoe_notifier);
dev_remove_pack(&pppoed_ptype);
dev_remove_pack(&pppoes_ptype);
unregister_pppox_proto(PX_PROTO_OE);
proto_unregister(&pppoe_sk_proto);
unregister_pernet_gen_device(pppoe_net_id, &pppoe_net_ops);
}
module_init(pppoe_init);
module_exit(pppoe_exit);
MODULE_AUTHOR("Michal Ostrowski <mostrows@speakeasy.net>");
MODULE_DESCRIPTION("PPP over Ethernet driver");
MODULE_LICENSE("GPL");
MODULE_ALIAS_NETPROTO(PF_PPPOX);
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