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l2tp_ppp.c
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/*****************************************************************************
* Linux PPP over L2TP (PPPoX/PPPoL2TP) Sockets
*
* PPPoX --- Generic PPP encapsulation socket family
* PPPoL2TP --- PPP over L2TP (RFC 2661)
*
* Version: 2.0.0
*
* Authors: James Chapman (jchapman@katalix.com)
*
* Based on original work by Martijn van Oosterhout <kleptog@svana.org>
*
* 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.
*
*/
/* This driver handles only L2TP data frames; control frames are handled by a
* userspace application.
*
* To send data in an L2TP session, userspace opens a PPPoL2TP socket and
* attaches it to a bound UDP socket with local tunnel_id / session_id and
* peer tunnel_id / session_id set. Data can then be sent or received using
* regular socket sendmsg() / recvmsg() calls. Kernel parameters of the socket
* can be read or modified using ioctl() or [gs]etsockopt() calls.
*
* When a PPPoL2TP socket is connected with local and peer session_id values
* zero, the socket is treated as a special tunnel management socket.
*
* Here's example userspace code to create a socket for sending/receiving data
* over an L2TP session:-
*
* struct sockaddr_pppol2tp sax;
* int fd;
* int session_fd;
*
* fd = socket(AF_PPPOX, SOCK_DGRAM, PX_PROTO_OL2TP);
*
* sax.sa_family = AF_PPPOX;
* sax.sa_protocol = PX_PROTO_OL2TP;
* sax.pppol2tp.fd = tunnel_fd; // bound UDP socket
* sax.pppol2tp.addr.sin_addr.s_addr = addr->sin_addr.s_addr;
* sax.pppol2tp.addr.sin_port = addr->sin_port;
* sax.pppol2tp.addr.sin_family = AF_INET;
* sax.pppol2tp.s_tunnel = tunnel_id;
* sax.pppol2tp.s_session = session_id;
* sax.pppol2tp.d_tunnel = peer_tunnel_id;
* sax.pppol2tp.d_session = peer_session_id;
*
* session_fd = connect(fd, (struct sockaddr *)&sax, sizeof(sax));
*
* A pppd plugin that allows PPP traffic to be carried over L2TP using
* this driver is available from the OpenL2TP project at
* http://openl2tp.sourceforge.net.
*/
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/module.h>
#include <linux/string.h>
#include <linux/list.h>
#include <linux/uaccess.h>
#include <linux/kernel.h>
#include <linux/spinlock.h>
#include <linux/kthread.h>
#include <linux/sched.h>
#include <linux/slab.h>
#include <linux/errno.h>
#include <linux/jiffies.h>
#include <linux/netdevice.h>
#include <linux/net.h>
#include <linux/inetdevice.h>
#include <linux/skbuff.h>
#include <linux/init.h>
#include <linux/ip.h>
#include <linux/udp.h>
#include <linux/if_pppox.h>
#include <linux/if_pppol2tp.h>
#include <net/sock.h>
#include <linux/ppp_channel.h>
#include <linux/ppp_defs.h>
#include <linux/ppp-ioctl.h>
#include <linux/file.h>
#include <linux/hash.h>
#include <linux/sort.h>
#include <linux/proc_fs.h>
#include <linux/l2tp.h>
#include <linux/nsproxy.h>
#include <net/net_namespace.h>
#include <net/netns/generic.h>
#include <net/dst.h>
#include <net/ip.h>
#include <net/udp.h>
#include <net/xfrm.h>
#include <net/inet_common.h>
#include <asm/byteorder.h>
#include <linux/atomic.h>
#include "l2tp_core.h"
#define PPPOL2TP_DRV_VERSION "V2.0"
/* Space for UDP, L2TP and PPP headers */
#define PPPOL2TP_HEADER_OVERHEAD 40
/* Number of bytes to build transmit L2TP headers.
* Unfortunately the size is different depending on whether sequence numbers
* are enabled.
*/
#define PPPOL2TP_L2TP_HDR_SIZE_SEQ 10
#define PPPOL2TP_L2TP_HDR_SIZE_NOSEQ 6
/* Private data of each session. This data lives at the end of struct
* l2tp_session, referenced via session->priv[].
*/
struct pppol2tp_session {
int owner; /* pid that opened the socket */
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 */
int flags; /* accessed by PPPIOCGFLAGS.
* Unused. */
};
static int pppol2tp_xmit(struct ppp_channel *chan, struct sk_buff *skb);
static const struct ppp_channel_ops pppol2tp_chan_ops = {
.start_xmit = pppol2tp_xmit,
};
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)
{
struct l2tp_session *session;
if (sk == NULL)
return NULL;
sock_hold(sk);
session = (struct l2tp_session *)(sk->sk_user_data);
if (session == NULL) {
sock_put(sk);
goto out;
}
BUG_ON(session->magic != L2TP_SESSION_MAGIC);
out:
return session;
}
/*****************************************************************************
* Receive data handling
*****************************************************************************/
static int pppol2tp_recv_payload_hook(struct sk_buff *skb)
{
/* Skip PPP header, if present. In testing, Microsoft L2TP clients
* don't send the PPP header (PPP header compression enabled), but
* other clients can include the header. So we cope with both cases
* here. The PPP header is always FF03 when using L2TP.
*
* Note that skb->data[] isn't dereferenced from a u16 ptr here since
* the field may be unaligned.
*/
if (!pskb_may_pull(skb, 2))
return 1;
if ((skb->data[0] == PPP_ALLSTATIONS) && (skb->data[1] == PPP_UI))
skb_pull(skb, 2);
return 0;
}
/* Receive message. This is the recvmsg for the PPPoL2TP socket.
*/
static int pppol2tp_recvmsg(struct socket *sock, struct msghdr *msg,
size_t len, int flags)
{
int err;
struct sk_buff *skb;
struct sock *sk = sock->sk;
err = -EIO;
if (sk->sk_state & PPPOX_BOUND)
goto end;
err = 0;
skb = skb_recv_datagram(sk, flags & ~MSG_DONTWAIT,
flags & MSG_DONTWAIT, &err);
if (!skb)
goto end;
if (len > skb->len)
len = skb->len;
else if (len < skb->len)
msg->msg_flags |= MSG_TRUNC;
err = skb_copy_datagram_msg(skb, 0, msg, len);
if (likely(err == 0))
err = len;
kfree_skb(skb);
end:
return err;
}
static void pppol2tp_recv(struct l2tp_session *session, struct sk_buff *skb, int data_len)
{
struct pppol2tp_session *ps = l2tp_session_priv(session);
struct sock *sk = NULL;
/* If the socket is bound, send it in to PPP's input queue. Otherwise
* queue it on the session socket.
*/
rcu_read_lock();
sk = rcu_dereference(ps->sk);
if (sk == NULL)
goto no_sock;
if (sk->sk_state & PPPOX_BOUND) {
struct pppox_sock *po;
l2tp_dbg(session, L2TP_MSG_DATA,
"%s: recv %d byte data frame, passing to ppp\n",
session->name, data_len);
po = pppox_sk(sk);
ppp_input(&po->chan, skb);
} else {
l2tp_dbg(session, L2TP_MSG_DATA,
"%s: recv %d byte data frame, passing to L2TP socket\n",
session->name, data_len);
if (sock_queue_rcv_skb(sk, skb) < 0) {
atomic_long_inc(&session->stats.rx_errors);
kfree_skb(skb);
}
}
rcu_read_unlock();
return;
no_sock:
rcu_read_unlock();
l2tp_info(session, L2TP_MSG_DATA, "%s: no socket\n", session->name);
kfree_skb(skb);
}
/************************************************************************
* Transmit handling
***********************************************************************/
/* This is the sendmsg for the PPPoL2TP pppol2tp_session socket. We come here
* when a user application does a sendmsg() on the session socket. L2TP and
* PPP headers must be inserted into the user's data.
*/
static int pppol2tp_sendmsg(struct socket *sock, struct msghdr *m,
size_t total_len)
{
struct sock *sk = sock->sk;
struct sk_buff *skb;
int error;
struct l2tp_session *session;
struct l2tp_tunnel *tunnel;
int uhlen;
error = -ENOTCONN;
if (sock_flag(sk, SOCK_DEAD) || !(sk->sk_state & PPPOX_CONNECTED))
goto error;
/* Get session and tunnel contexts */
error = -EBADF;
session = pppol2tp_sock_to_session(sk);
if (session == NULL)
goto error;
tunnel = session->tunnel;
uhlen = (tunnel->encap == L2TP_ENCAPTYPE_UDP) ? sizeof(struct udphdr) : 0;
/* Allocate a socket buffer */
error = -ENOMEM;
skb = sock_wmalloc(sk, NET_SKB_PAD + sizeof(struct iphdr) +
uhlen + session->hdr_len +
2 + total_len, /* 2 bytes for PPP_ALLSTATIONS & PPP_UI */
0, GFP_KERNEL);
if (!skb)
goto error_put_sess;
/* Reserve space for headers. */
skb_reserve(skb, NET_SKB_PAD);
skb_reset_network_header(skb);
skb_reserve(skb, sizeof(struct iphdr));
skb_reset_transport_header(skb);
skb_reserve(skb, uhlen);
/* Add PPP header */
skb->data[0] = PPP_ALLSTATIONS;
skb->data[1] = PPP_UI;
skb_put(skb, 2);
/* Copy user data into skb */
error = memcpy_from_msg(skb_put(skb, total_len), m, total_len);
if (error < 0) {
kfree_skb(skb);
goto error_put_sess;
}
local_bh_disable();
l2tp_xmit_skb(session, skb, session->hdr_len);
local_bh_enable();
sock_put(sk);
return total_len;
error_put_sess:
sock_put(sk);
error:
return error;
}
/* Transmit function called by generic PPP driver. Sends PPP frame
* over PPPoL2TP socket.
*
* This is almost the same as pppol2tp_sendmsg(), but rather than
* being called with a msghdr from userspace, it is called with a skb
* from the kernel.
*
* The supplied skb from ppp doesn't have enough headroom for the
* insertion of L2TP, UDP and IP headers so we need to allocate more
* headroom in the skb. This will create a cloned skb. But we must be
* careful in the error case because the caller will expect to free
* the skb it supplied, not our cloned skb. So we take care to always
* leave the original skb unfreed if we return an error.
*/
static int pppol2tp_xmit(struct ppp_channel *chan, struct sk_buff *skb)
{
struct sock *sk = (struct sock *) chan->private;
struct l2tp_session *session;
struct l2tp_tunnel *tunnel;
int uhlen, headroom;
if (sock_flag(sk, SOCK_DEAD) || !(sk->sk_state & PPPOX_CONNECTED))
goto abort;
/* Get session and tunnel contexts from the socket */
session = pppol2tp_sock_to_session(sk);
if (session == NULL)
goto abort;
tunnel = session->tunnel;
uhlen = (tunnel->encap == L2TP_ENCAPTYPE_UDP) ? sizeof(struct udphdr) : 0;
headroom = NET_SKB_PAD +
sizeof(struct iphdr) + /* IP header */
uhlen + /* UDP header (if L2TP_ENCAPTYPE_UDP) */
session->hdr_len + /* L2TP header */
2; /* 2 bytes for PPP_ALLSTATIONS & PPP_UI */
if (skb_cow_head(skb, headroom))
goto abort_put_sess;
/* Setup PPP header */
__skb_push(skb, 2);
skb->data[0] = PPP_ALLSTATIONS;
skb->data[1] = PPP_UI;
local_bh_disable();
l2tp_xmit_skb(session, skb, session->hdr_len);
local_bh_enable();
sock_put(sk);
return 1;
abort_put_sess:
sock_put(sk);
abort:
/* Free the original skb */
kfree_skb(skb);
return 1;
}
/*****************************************************************************
* Session (and tunnel control) socket create/destroy.
*****************************************************************************/
static void pppol2tp_put_sk(struct rcu_head *head)
{
struct pppol2tp_session *ps;
ps = container_of(head, typeof(*ps), rcu);
sock_put(ps->__sk);
}
/* Really kill the session socket. (Called from sock_put() if
* refcnt == 0.)
*/
static void pppol2tp_session_destruct(struct sock *sk)
{
struct l2tp_session *session = sk->sk_user_data;
skb_queue_purge(&sk->sk_receive_queue);
skb_queue_purge(&sk->sk_write_queue);
if (session) {
sk->sk_user_data = NULL;
BUG_ON(session->magic != L2TP_SESSION_MAGIC);
l2tp_session_dec_refcount(session);
}
}
/* Called when the PPPoX socket (session) is closed.
*/
static int pppol2tp_release(struct socket *sock)
{
struct sock *sk = sock->sk;
struct l2tp_session *session;
int error;
if (!sk)
return 0;
error = -EBADF;
lock_sock(sk);
if (sock_flag(sk, SOCK_DEAD) != 0)
goto error;
pppox_unbind_sock(sk);
/* Signal the death of the socket. */
sk->sk_state = PPPOX_DEAD;
sock_orphan(sk);
sock->sk = NULL;
session = pppol2tp_sock_to_session(sk);
if (session) {
struct pppol2tp_session *ps;
l2tp_session_delete(session);
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().
*/
}
release_sock(sk);
/* This will delete the session context via
* pppol2tp_session_destruct() if the socket's refcnt drops to
* zero.
*/
sock_put(sk);
return 0;
error:
release_sock(sk);
return error;
}
static struct proto pppol2tp_sk_proto = {
.name = "PPPOL2TP",
.owner = THIS_MODULE,
.obj_size = sizeof(struct pppox_sock),
};
static int pppol2tp_backlog_recv(struct sock *sk, struct sk_buff *skb)
{
int rc;
rc = l2tp_udp_encap_recv(sk, skb);
if (rc)
kfree_skb(skb);
return NET_RX_SUCCESS;
}
/* socket() handler. Initialize a new struct sock.
*/
static int pppol2tp_create(struct net *net, struct socket *sock, int kern)
{
int error = -ENOMEM;
struct sock *sk;
sk = sk_alloc(net, PF_PPPOX, GFP_KERNEL, &pppol2tp_sk_proto, kern);
if (!sk)
goto out;
sock_init_data(sock, sk);
sock->state = SS_UNCONNECTED;
sock->ops = &pppol2tp_ops;
sk->sk_backlog_rcv = pppol2tp_backlog_recv;
sk->sk_protocol = PX_PROTO_OL2TP;
sk->sk_family = PF_PPPOX;
sk->sk_state = PPPOX_NONE;
sk->sk_type = SOCK_STREAM;
sk->sk_destruct = pppol2tp_session_destruct;
error = 0;
out:
return error;
}
#if IS_ENABLED(CONFIG_L2TP_DEBUGFS)
static void pppol2tp_show(struct seq_file *m, void *arg)
{
struct l2tp_session *session = arg;
struct sock *sk;
sk = pppol2tp_session_get_sock(session);
if (sk) {
struct pppox_sock *po = pppox_sk(sk);
seq_printf(m, " interface %s\n", ppp_dev_name(&po->chan));
sock_put(sk);
}
}
#endif
static void pppol2tp_session_init(struct l2tp_session *session)
{
struct pppol2tp_session *ps;
struct dst_entry *dst;
session->recv_skb = pppol2tp_recv;
#if IS_ENABLED(CONFIG_L2TP_DEBUGFS)
session->show = pppol2tp_show;
#endif
ps = l2tp_session_priv(session);
mutex_init(&ps->sk_lock);
ps->owner = current->pid;
/* If PMTU discovery was enabled, use the MTU that was discovered */
dst = sk_dst_get(session->tunnel->sock);
if (dst) {
u32 pmtu = dst_mtu(dst);
if (pmtu) {
session->mtu = pmtu - PPPOL2TP_HEADER_OVERHEAD;
session->mru = pmtu - PPPOL2TP_HEADER_OVERHEAD;
}
dst_release(dst);
}
}
struct l2tp_connect_info {
u8 version;
int fd;
u32 tunnel_id;
u32 peer_tunnel_id;
u32 session_id;
u32 peer_session_id;
};
static int pppol2tp_sockaddr_get_info(const void *sa, int sa_len,
struct l2tp_connect_info *info)
{
switch (sa_len) {
case sizeof(struct sockaddr_pppol2tp):
{
const struct sockaddr_pppol2tp *sa_v2in4 = sa;
if (sa_v2in4->sa_protocol != PX_PROTO_OL2TP)
return -EINVAL;
info->version = 2;
info->fd = sa_v2in4->pppol2tp.fd;
info->tunnel_id = sa_v2in4->pppol2tp.s_tunnel;
info->peer_tunnel_id = sa_v2in4->pppol2tp.d_tunnel;
info->session_id = sa_v2in4->pppol2tp.s_session;
info->peer_session_id = sa_v2in4->pppol2tp.d_session;
break;
}
case sizeof(struct sockaddr_pppol2tpv3):
{
const struct sockaddr_pppol2tpv3 *sa_v3in4 = sa;
if (sa_v3in4->sa_protocol != PX_PROTO_OL2TP)
return -EINVAL;
info->version = 3;
info->fd = sa_v3in4->pppol2tp.fd;
info->tunnel_id = sa_v3in4->pppol2tp.s_tunnel;
info->peer_tunnel_id = sa_v3in4->pppol2tp.d_tunnel;
info->session_id = sa_v3in4->pppol2tp.s_session;
info->peer_session_id = sa_v3in4->pppol2tp.d_session;
break;
}
case sizeof(struct sockaddr_pppol2tpin6):
{
const struct sockaddr_pppol2tpin6 *sa_v2in6 = sa;
if (sa_v2in6->sa_protocol != PX_PROTO_OL2TP)
return -EINVAL;
info->version = 2;
info->fd = sa_v2in6->pppol2tp.fd;
info->tunnel_id = sa_v2in6->pppol2tp.s_tunnel;
info->peer_tunnel_id = sa_v2in6->pppol2tp.d_tunnel;
info->session_id = sa_v2in6->pppol2tp.s_session;
info->peer_session_id = sa_v2in6->pppol2tp.d_session;
break;
}
case sizeof(struct sockaddr_pppol2tpv3in6):
{
const struct sockaddr_pppol2tpv3in6 *sa_v3in6 = sa;
if (sa_v3in6->sa_protocol != PX_PROTO_OL2TP)
return -EINVAL;
info->version = 3;
info->fd = sa_v3in6->pppol2tp.fd;
info->tunnel_id = sa_v3in6->pppol2tp.s_tunnel;
info->peer_tunnel_id = sa_v3in6->pppol2tp.d_tunnel;
info->session_id = sa_v3in6->pppol2tp.s_session;
info->peer_session_id = sa_v3in6->pppol2tp.d_session;
break;
}
default:
return -EINVAL;
}
return 0;
}
/* connect() handler. Attach a PPPoX socket to a tunnel UDP socket
*/
static int pppol2tp_connect(struct socket *sock, struct sockaddr *uservaddr,
int sockaddr_len, int flags)
{
struct sock *sk = sock->sk;
struct pppox_sock *po = pppox_sk(sk);
struct l2tp_session *session = NULL;
struct l2tp_connect_info info;
struct l2tp_tunnel *tunnel;
struct pppol2tp_session *ps;
struct l2tp_session_cfg cfg = { 0, };
bool drop_refcnt = false;
bool drop_tunnel = false;
bool new_session = false;
bool new_tunnel = false;
int error;
error = pppol2tp_sockaddr_get_info(uservaddr, sockaddr_len, &info);
if (error < 0)
return error;
lock_sock(sk);
/* Check for already bound sockets */
error = -EBUSY;
if (sk->sk_state & PPPOX_CONNECTED)
goto end;
/* We don't supporting rebinding anyway */
error = -EALREADY;
if (sk->sk_user_data)
goto end; /* socket is already attached */
/* Don't bind if tunnel_id is 0 */
error = -EINVAL;
if (!info.tunnel_id)
goto end;
tunnel = l2tp_tunnel_get(sock_net(sk), info.tunnel_id);
if (tunnel)
drop_tunnel = true;
/* Special case: create tunnel context if session_id and
* peer_session_id is 0. Otherwise look up tunnel using supplied
* tunnel id.
*/
if (!info.session_id && !info.peer_session_id) {
if (tunnel == NULL) {
struct l2tp_tunnel_cfg tcfg = {
.encap = L2TP_ENCAPTYPE_UDP,
.debug = 0,
};
/* Prevent l2tp_tunnel_register() from trying to set up
* a kernel socket.
*/
if (info.fd < 0) {
error = -EBADF;
goto end;
}
error = l2tp_tunnel_create(sock_net(sk), info.fd,
info.version,
info.tunnel_id,
info.peer_tunnel_id, &tcfg,
&tunnel);
if (error < 0)
goto end;
l2tp_tunnel_inc_refcount(tunnel);
error = l2tp_tunnel_register(tunnel, sock_net(sk),
&tcfg);
if (error < 0) {
kfree(tunnel);
goto end;
}
drop_tunnel = true;
new_tunnel = true;
}
} else {
/* Error if we can't find the tunnel */
error = -ENOENT;
if (tunnel == NULL)
goto end;
/* Error if socket is not prepped */
if (tunnel->sock == NULL)
goto end;
}
if (tunnel->recv_payload_hook == NULL)
tunnel->recv_payload_hook = pppol2tp_recv_payload_hook;
if (tunnel->peer_tunnel_id == 0)
tunnel->peer_tunnel_id = info.peer_tunnel_id;
session = l2tp_session_get(sock_net(sk), tunnel, info.session_id);
if (session) {
drop_refcnt = true;
if (session->pwtype != L2TP_PWTYPE_PPP) {
error = -EPROTOTYPE;
goto end;
}
ps = l2tp_session_priv(session);
/* Using a pre-existing session is fine as long as it hasn't
* been connected yet.
*/
mutex_lock(&ps->sk_lock);
if (rcu_dereference_protected(ps->sk,
lockdep_is_held(&ps->sk_lock)) ||
ps->__sk) {
mutex_unlock(&ps->sk_lock);
error = -EEXIST;
goto end;
}
} else {
/* Default MTU must allow space for UDP/L2TP/PPP headers */
cfg.mtu = 1500 - PPPOL2TP_HEADER_OVERHEAD;
cfg.mru = cfg.mtu;
cfg.pw_type = L2TP_PWTYPE_PPP;
session = l2tp_session_create(sizeof(struct pppol2tp_session),
tunnel, info.session_id,
info.peer_session_id, &cfg);
if (IS_ERR(session)) {
error = PTR_ERR(session);
goto end;
}
pppol2tp_session_init(session);
ps = l2tp_session_priv(session);
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;
new_session = true;
}
/* Special case: if source & dest session_id == 0x0000, this
* socket is being created to manage the tunnel. Just set up
* the internal context for use by ioctl() and sockopt()
* handlers.
*/
if ((session->session_id == 0) &&
(session->peer_session_id == 0)) {
error = 0;
goto out_no_ppp;
}
/* The only header we need to worry about is the L2TP
* header. This size is different depending on whether
* sequence numbers are enabled for the data channel.
*/
po->chan.hdrlen = PPPOL2TP_L2TP_HDR_SIZE_NOSEQ;
po->chan.private = sk;
po->chan.ops = &pppol2tp_chan_ops;
po->chan.mtu = session->mtu;
error = ppp_register_net_channel(sock_net(sk), &po->chan);
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);
/* Keep the reference we've grabbed on the session: sk doesn't expect
* the session to disappear. pppol2tp_session_destruct() is responsible
* for dropping it.
*/
drop_refcnt = false;
sk->sk_state = PPPOX_CONNECTED;
l2tp_info(session, L2TP_MSG_CONTROL, "%s: created\n",
session->name);
end:
if (error) {
if (new_session)
l2tp_session_delete(session);
if (new_tunnel)
l2tp_tunnel_delete(tunnel);
}
if (drop_refcnt)
l2tp_session_dec_refcount(session);
if (drop_tunnel)
l2tp_tunnel_dec_refcount(tunnel);
release_sock(sk);
return error;
}
#ifdef CONFIG_L2TP_V3
/* Called when creating sessions via the netlink interface. */
static int pppol2tp_session_create(struct net *net, struct l2tp_tunnel *tunnel,
u32 session_id, u32 peer_session_id,
struct l2tp_session_cfg *cfg)
{
int error;
struct l2tp_session *session;
/* Error if tunnel socket is not prepped */
if (!tunnel->sock) {
error = -ENOENT;
goto err;
}
/* Default MTU values. */
if (cfg->mtu == 0)
cfg->mtu = 1500 - PPPOL2TP_HEADER_OVERHEAD;
if (cfg->mru == 0)
cfg->mru = cfg->mtu;
/* Allocate and initialize a new session context. */
session = l2tp_session_create(sizeof(struct pppol2tp_session),
tunnel, session_id,
peer_session_id, cfg);
if (IS_ERR(session)) {
error = PTR_ERR(session);
goto err;
}
pppol2tp_session_init(session);
error = l2tp_session_register(session, tunnel);
if (error < 0)
goto err_sess;
return 0;
err_sess:
kfree(session);
err:
return error;
}
#endif /* CONFIG_L2TP_V3 */
/* getname() support.
*/
static int pppol2tp_getname(struct socket *sock, struct sockaddr *uaddr,
int peer)
{
int len = 0;
int error = 0;
struct l2tp_session *session;
struct l2tp_tunnel *tunnel;
struct sock *sk = sock->sk;
struct inet_sock *inet;
struct pppol2tp_session *pls;
error = -ENOTCONN;
if (sk == NULL)
goto end;
if (!(sk->sk_state & PPPOX_CONNECTED))
goto end;
error = -EBADF;
session = pppol2tp_sock_to_session(sk);
if (session == NULL)
goto end;
pls = l2tp_session_priv(session);
tunnel = session->tunnel;
inet = inet_sk(tunnel->sock);
if ((tunnel->version == 2) && (tunnel->sock->sk_family == AF_INET)) {
struct sockaddr_pppol2tp sp;
len = sizeof(sp);
memset(&sp, 0, len);
sp.sa_family = AF_PPPOX;
sp.sa_protocol = PX_PROTO_OL2TP;
sp.pppol2tp.fd = tunnel->fd;
sp.pppol2tp.pid = pls->owner;
sp.pppol2tp.s_tunnel = tunnel->tunnel_id;
sp.pppol2tp.d_tunnel = tunnel->peer_tunnel_id;
sp.pppol2tp.s_session = session->session_id;
sp.pppol2tp.d_session = session->peer_session_id;
sp.pppol2tp.addr.sin_family = AF_INET;
sp.pppol2tp.addr.sin_port = inet->inet_dport;
sp.pppol2tp.addr.sin_addr.s_addr = inet->inet_daddr;
memcpy(uaddr, &sp, len);
#if IS_ENABLED(CONFIG_IPV6)
} else if ((tunnel->version == 2) &&
(tunnel->sock->sk_family == AF_INET6)) {
struct sockaddr_pppol2tpin6 sp;
len = sizeof(sp);
memset(&sp, 0, len);
sp.sa_family = AF_PPPOX;
sp.sa_protocol = PX_PROTO_OL2TP;
sp.pppol2tp.fd = tunnel->fd;
sp.pppol2tp.pid = pls->owner;
sp.pppol2tp.s_tunnel = tunnel->tunnel_id;
sp.pppol2tp.d_tunnel = tunnel->peer_tunnel_id;
sp.pppol2tp.s_session = session->session_id;
sp.pppol2tp.d_session = session->peer_session_id;
sp.pppol2tp.addr.sin6_family = AF_INET6;
sp.pppol2tp.addr.sin6_port = inet->inet_dport;
memcpy(&sp.pppol2tp.addr.sin6_addr, &tunnel->sock->sk_v6_daddr,
sizeof(tunnel->sock->sk_v6_daddr));
memcpy(uaddr, &sp, len);
} else if ((tunnel->version == 3) &&
(tunnel->sock->sk_family == AF_INET6)) {
struct sockaddr_pppol2tpv3in6 sp;
len = sizeof(sp);
memset(&sp, 0, len);
sp.sa_family = AF_PPPOX;
sp.sa_protocol = PX_PROTO_OL2TP;