struct pppol2tp_session {
int owner; /* pid that opened the socket */
- struct sock *sock; /* Pointer to the session
+ struct mutex sk_lock; /* Protects .sk */
+ struct sock __rcu *sk; /* Pointer to the session
* PPPoX socket */
+ struct sock *__sk; /* Copy of .sk, for cleanup */
+ struct rcu_head rcu; /* For asynchronous release */
struct sock *tunnel_sock; /* Pointer to the tunnel UDP
* socket */
int flags; /* accessed by PPPIOCGFLAGS.
static const struct proto_ops pppol2tp_ops;
+/* Retrieves the pppol2tp socket associated to a session.
+ * A reference is held on the returned socket, so this function must be paired
+ * with sock_put().
+ */
+static struct sock *pppol2tp_session_get_sock(struct l2tp_session *session)
+{
+ struct pppol2tp_session *ps = l2tp_session_priv(session);
+ struct sock *sk;
+
+ rcu_read_lock();
+ sk = rcu_dereference(ps->sk);
+ if (sk)
+ sock_hold(sk);
+ rcu_read_unlock();
+
+ return sk;
+}
+
/* Helpers to obtain tunnel/session contexts from sockets.
*/
static inline struct l2tp_session *pppol2tp_sock_to_session(struct sock *sk)
/* If the socket is bound, send it in to PPP's input queue. Otherwise
* queue it on the session socket.
*/
- sk = ps->sock;
+ rcu_read_lock();
+ sk = rcu_dereference(ps->sk);
if (sk == NULL)
goto no_sock;
session->stats.rx_errors++;
kfree_skb(skb);
}
+ rcu_read_unlock();
return;
no_sock:
+ rcu_read_unlock();
PRINTK(session->debug, PPPOL2TP_MSG_DATA, KERN_INFO,
"%s: no socket\n", session->name);
kfree_skb(skb);
}
-static void pppol2tp_session_sock_hold(struct l2tp_session *session)
-{
- struct pppol2tp_session *ps = l2tp_session_priv(session);
-
- if (ps->sock)
- sock_hold(ps->sock);
-}
-
-static void pppol2tp_session_sock_put(struct l2tp_session *session)
-{
- struct pppol2tp_session *ps = l2tp_session_priv(session);
-
- if (ps->sock)
- sock_put(ps->sock);
-}
-
/************************************************************************
* Transmit handling
***********************************************************************/
*/
static void pppol2tp_session_close(struct l2tp_session *session)
{
- struct pppol2tp_session *ps = l2tp_session_priv(session);
- struct sock *sk = ps->sock;
- struct socket *sock = sk->sk_socket;
+ struct sock *sk;
BUG_ON(session->magic != L2TP_SESSION_MAGIC);
- if (sock)
- inet_shutdown(sock, 2);
+ sk = pppol2tp_session_get_sock(session);
+ if (sk) {
+ if (sk->sk_socket)
+ inet_shutdown(sk->sk_socket, SEND_SHUTDOWN);
+ sock_put(sk);
+ }
/* Don't let the session go away before our socket does */
l2tp_session_inc_refcount(session);
return;
}
+static void pppol2tp_put_sk(struct rcu_head *head)
+{
+ struct pppol2tp_session *ps;
+
+ ps = container_of(head, typeof(*ps), rcu);
+ sock_put(ps->__sk);
+}
+
/* Called when the PPPoX socket (session) is closed.
*/
static int pppol2tp_release(struct socket *sock)
session = pppol2tp_sock_to_session(sk);
- /* Purge any queued data */
if (session != NULL) {
+ struct pppol2tp_session *ps;
+
l2tp_session_queue_purge(session);
- sock_put(sk);
+
+ ps = l2tp_session_priv(session);
+ mutex_lock(&ps->sk_lock);
+ ps->__sk = rcu_dereference_protected(ps->sk,
+ lockdep_is_held(&ps->sk_lock));
+ RCU_INIT_POINTER(ps->sk, NULL);
+ mutex_unlock(&ps->sk_lock);
+ call_rcu(&ps->rcu, pppol2tp_put_sk);
+
+ /* Rely on the sock_put() call at the end of the function for
+ * dropping the reference held by pppol2tp_sock_to_session().
+ * The last reference will be dropped by pppol2tp_put_sk().
+ */
}
skb_queue_purge(&sk->sk_receive_queue);
skb_queue_purge(&sk->sk_write_queue);
static void pppol2tp_show(struct seq_file *m, void *arg)
{
struct l2tp_session *session = arg;
- struct pppol2tp_session *ps = l2tp_session_priv(session);
+ struct sock *sk;
+
+ sk = pppol2tp_session_get_sock(session);
+ if (sk) {
+ struct pppox_sock *po = pppox_sk(sk);
- if (ps) {
- struct pppox_sock *po = pppox_sk(ps->sock);
- if (po)
- seq_printf(m, " interface %s\n", ppp_dev_name(&po->chan));
+ seq_printf(m, " interface %s\n", ppp_dev_name(&po->chan));
+ sock_put(sk);
}
}
#endif
/* Using a pre-existing session is fine as long as it hasn't
* been connected yet.
*/
- if (ps->sock) {
+ mutex_lock(&ps->sk_lock);
+ if (rcu_dereference_protected(ps->sk,
+ lockdep_is_held(&ps->sk_lock))) {
+ mutex_unlock(&ps->sk_lock);
error = -EEXIST;
goto end;
}
/* consistency checks */
if (ps->tunnel_sock != tunnel->sock) {
+ mutex_unlock(&ps->sk_lock);
error = -EEXIST;
goto end;
}
goto end;
}
+ ps = l2tp_session_priv(session);
+ mutex_init(&ps->sk_lock);
l2tp_session_inc_refcount(session);
+
+ mutex_lock(&ps->sk_lock);
error = l2tp_session_register(session, tunnel);
if (error < 0) {
+ mutex_unlock(&ps->sk_lock);
kfree(session);
goto end;
}
drop_refcnt = true;
}
- /* Associate session with its PPPoL2TP socket */
- ps = l2tp_session_priv(session);
ps->owner = current->pid;
- ps->sock = sk;
ps->tunnel_sock = tunnel->sock;
session->recv_skb = pppol2tp_recv;
session->show = pppol2tp_show;
#endif
- /* We need to know each time a skb is dropped from the reorder
- * queue.
- */
- session->ref = pppol2tp_session_sock_hold;
- session->deref = pppol2tp_session_sock_put;
-
/* If PMTU discovery was enabled, use the MTU that was discovered */
dst = sk_dst_get(tunnel->sock);
if (dst != NULL) {
po->chan.mtu = session->mtu;
error = ppp_register_net_channel(sock_net(sk), &po->chan);
- if (error)
+ if (error) {
+ mutex_unlock(&ps->sk_lock);
goto end;
+ }
out_no_ppp:
/* This is how we get the session context from the socket. */
sk->sk_user_data = session;
+ rcu_assign_pointer(ps->sk, sk);
+ mutex_unlock(&ps->sk_lock);
+
sk->sk_state = PPPOX_CONNECTED;
PRINTK(session->debug, PPPOL2TP_MSG_CONTROL, KERN_INFO,
"%s: created\n", session->name);
}
ps = l2tp_session_priv(session);
+ mutex_init(&ps->sk_lock);
ps->tunnel_sock = tunnel->sock;
error = l2tp_session_register(session, tunnel);
"%s: pppol2tp_session_ioctl(cmd=%#x, arg=%#lx)\n",
session->name, cmd, arg);
- sk = ps->sock;
+ sk = pppol2tp_session_get_sock(session);
if (!sk)
return -EBADR;
- sock_hold(sk);
-
switch (cmd) {
case SIOCGIFMTU:
err = -ENXIO;
int optname, int val)
{
int err = 0;
- struct pppol2tp_session *ps = l2tp_session_priv(session);
switch (optname) {
case PPPOL2TP_SO_RECVSEQ:
}
session->send_seq = val ? -1 : 0;
{
- struct sock *ssk = ps->sock;
- struct pppox_sock *po = pppox_sk(ssk);
+ struct pppox_sock *po = pppox_sk(sk);
+
po->chan.hdrlen = val ? PPPOL2TP_L2TP_HDR_SIZE_SEQ :
PPPOL2TP_L2TP_HDR_SIZE_NOSEQ;
}
{
struct l2tp_session *session = v;
struct l2tp_tunnel *tunnel = session->tunnel;
- struct pppol2tp_session *ps = l2tp_session_priv(session);
- struct pppox_sock *po = pppox_sk(ps->sock);
+ unsigned char state;
+ char user_data_ok;
+ struct sock *sk;
u32 ip = 0;
u16 port = 0;
port = ntohs(inet->inet_sport);
}
+ sk = pppol2tp_session_get_sock(session);
+ if (sk) {
+ state = sk->sk_state;
+ user_data_ok = (session == sk->sk_user_data) ? 'Y' : 'N';
+ } else {
+ state = 0;
+ user_data_ok = 'N';
+ }
+
seq_printf(m, " SESSION '%s' %08X/%d %04X/%04X -> "
"%04X/%04X %d %c\n",
session->name, ip, port,
session->session_id,
tunnel->peer_tunnel_id,
session->peer_session_id,
- ps->sock->sk_state,
- (session == ps->sock->sk_user_data) ?
- 'Y' : 'N');
+ state, user_data_ok);
seq_printf(m, " %d/%d/%c/%c/%s %08x %u\n",
session->mtu, session->mru,
session->recv_seq ? 'R' : '-',
(unsigned long long)session->stats.rx_bytes,
(unsigned long long)session->stats.rx_errors);
- if (po)
+ if (sk) {
+ struct pppox_sock *po = pppox_sk(sk);
+
seq_printf(m, " interface %s\n", ppp_dev_name(&po->chan));
+ sock_put(sk);
+ }
}
static int pppol2tp_seq_show(struct seq_file *m, void *v)
git.openpandora.org / pandora-kernel.git / blobdiff