/
pppoe.c
1208 lines (989 loc) · 27.5 KB
/
pppoe.c
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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_xmit(struct sock *sk, struct sk_buff *skb);
static const struct proto_ops pppoe_ops;
static const struct ppp_channel_ops pppoe_chan_ops;
/* per-net private data for this module */
static int pppoe_net_id __read_mostly;
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 simpler 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 = NULL;
int ifindex;
rcu_read_lock();
dev = dev_get_by_name_rcu(net, sp->sa_addr.pppoe.dev);
if (dev) {
ifindex = dev->ifindex;
pn = pppoe_pernet(net);
pppox_sock = get_item(pn, sp->sa_addr.pppoe.sid,
sp->sa_addr.pppoe.remote, ifindex);
}
rcu_read_unlock();
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;
pn = pppoe_pernet(dev_net(dev));
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_ZOMBIE)) {
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_CHANGEADDR:
case NETDEV_CHANGEMTU:
/* A change in mtu or address 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 const 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;
}