* Driver for PPP on L2TP Access Concentrator / PPPoLAC Socket (RFC 2661)
*
* Copyright (C) 2009 Google, Inc.
- * Author: Chia-chi Yeh <chiachi@android.com>
*
* This software is licensed under the terms of the GNU General Public
* License version 2, as published by the Free Software Foundation, and
* only works on IPv4 due to the lack of UDP encapsulation support in IPv6. */
#include <linux/module.h>
+#include <linux/workqueue.h>
#include <linux/skbuff.h>
#include <linux/file.h>
+#include <linux/netdevice.h>
#include <linux/net.h>
#include <linux/udp.h>
#include <linux/ppp_defs.h>
#include <linux/if_pppox.h>
#include <linux/ppp_channel.h>
#include <net/tcp_states.h>
+#include <asm/uaccess.h>
-#define L2TP_CONTROL_MASK 0x80
-#define L2TP_VERSION_MASK 0x0F
+#define L2TP_CONTROL_BIT 0x80
+#define L2TP_LENGTH_BIT 0x40
+#define L2TP_SEQUENCE_BIT 0x08
+#define L2TP_OFFSET_BIT 0x02
#define L2TP_VERSION 0x02
-#define L2TP_LENGTH_MASK 0x40
-#define L2TP_OFFSET_MASK 0x02
-#define L2TP_SEQUENCE_MASK 0x08
+#define L2TP_VERSION_MASK 0x0F
#define PPP_ADDR 0xFF
#define PPP_CTRL 0x03
return (union unaligned *)ptr;
}
-static int pppolac_recv(struct sock *sk_udp, struct sk_buff *skb)
+static int pppolac_recv_core(struct sock *sk_udp, struct sk_buff *skb)
{
- struct sock *sk;
- struct pppolac_opt *opt;
+ struct sock *sk = (struct sock *)sk_udp->sk_user_data;
+ struct pppolac_opt *opt = &pppox_sk(sk)->proto.lac;
__u8 bits;
__u8 *ptr;
goto drop;
/* Put it back if it is a control packet. */
- if (skb->data[sizeof(struct udphdr)] & L2TP_CONTROL_MASK)
- return 1;
+ if (skb->data[sizeof(struct udphdr)] & L2TP_CONTROL_BIT)
+ return opt->backlog_rcv(sk_udp, skb);
- /* Now the packet is ours. Skip UDP header. */
+ /* Skip UDP header. */
skb_pull(skb, sizeof(struct udphdr));
/* Check the version. */
ptr = &skb->data[2];
/* Check the length if it is present. */
- if (bits & L2TP_LENGTH_MASK) {
+ if (bits & L2TP_LENGTH_BIT) {
if ((ptr[0] << 8 | ptr[1]) != skb->len)
goto drop;
ptr += 2;
}
/* Skip all fields including optional ones. */
- if (!skb_pull(skb, 6 + (bits & L2TP_SEQUENCE_MASK ? 4 : 0) +
- (bits & L2TP_LENGTH_MASK ? 2 : 0) +
- (bits & L2TP_OFFSET_MASK ? 2 : 0)))
+ if (!skb_pull(skb, 6 + (bits & L2TP_SEQUENCE_BIT ? 4 : 0) +
+ (bits & L2TP_LENGTH_BIT ? 2 : 0) +
+ (bits & L2TP_OFFSET_BIT ? 2 : 0)))
goto drop;
/* Skip the offset padding if it is present. */
- if (bits & L2TP_OFFSET_MASK &&
+ if (bits & L2TP_OFFSET_BIT &&
!skb_pull(skb, skb->data[-2] << 8 | skb->data[-1]))
goto drop;
- /* Now ptr is pointing to the tunnel and skb is pointing to the payload.
- * We have to lock sk_udp to prevent sk from being closed. */
- lock_sock(sk_udp);
- sk = sk_udp->sk_user_data;
- if (!sk) {
- release_sock(sk_udp);
- goto drop;
- }
- sock_hold(sk);
- release_sock(sk_udp);
- opt = &pppox_sk(sk)->proto.lac;
-
/* Check the tunnel and the session. */
- if (unaligned(ptr)->u32 != opt->local) {
- sock_put(sk);
+ if (unaligned(ptr)->u32 != opt->local)
goto drop;
- }
- /* Check the sequence if it is present. According to RFC 2661 page 10
- * and 43, the only thing to do is updating opt->sequencing. */
- opt->sequencing = bits & L2TP_SEQUENCE_MASK;
+ /* Check the sequence if it is present. According to RFC 2661 section
+ * 5.4, the only thing to do is to update opt->sequencing. */
+ opt->sequencing = bits & L2TP_SEQUENCE_BIT;
/* Skip PPP address and control if they are present. */
if (skb->len >= 2 && skb->data[0] == PPP_ADDR &&
if (skb->len >= 1 && skb->data[0] & 1)
skb_push(skb, 1)[0] = 0;
- /* Finally, deliver the packet to PPP channel. We have to lock sk to
- * prevent another thread from calling pppox_unbind_sock(). */
+ /* Finally, deliver the packet to PPP channel. */
skb_orphan(skb);
- lock_sock(sk);
ppp_input(&pppox_sk(sk)->chan, skb);
- release_sock(sk);
- sock_put(sk);
- return 0;
-
+ return NET_RX_SUCCESS;
drop:
kfree_skb(skb);
+ return NET_RX_DROP;
+}
+
+static int pppolac_recv(struct sock *sk_udp, struct sk_buff *skb)
+{
+ sock_hold(sk_udp);
+ sk_receive_skb(sk_udp, skb, 0);
return 0;
}
+static struct sk_buff_head delivery_queue;
+
+static void pppolac_xmit_core(struct work_struct *delivery_work)
+{
+ mm_segment_t old_fs = get_fs();
+ struct sk_buff *skb;
+
+ set_fs(KERNEL_DS);
+ while ((skb = skb_dequeue(&delivery_queue))) {
+ struct sock *sk_udp = skb->sk;
+ struct kvec iov = {.iov_base = skb->data, .iov_len = skb->len};
+ struct user_msghdr msg = {
+ .msg_iov = (struct iovec *)&iov,
+ .msg_iovlen = 1,
+ .msg_flags = MSG_NOSIGNAL | MSG_DONTWAIT,
+ };
+ sk_udp->sk_prot->sendmsg(NULL, sk_udp, &msg, skb->len);
+ kfree_skb(skb);
+ }
+ set_fs(old_fs);
+}
+
+static DECLARE_WORK(delivery_work, pppolac_xmit_core);
+
static int pppolac_xmit(struct ppp_channel *chan, struct sk_buff *skb)
{
struct sock *sk_udp = (struct sock *)chan->private;
struct pppolac_opt *opt = &pppox_sk(sk_udp->sk_user_data)->proto.lac;
- struct msghdr msg = {.msg_flags = MSG_NOSIGNAL | MSG_DONTWAIT};
- struct kvec iov;
/* Install PPP address and control. */
skb_push(skb, 2);
/* Install L2TP header. */
if (opt->sequencing) {
skb_push(skb, 10);
- skb->data[0] = L2TP_SEQUENCE_MASK;
+ skb->data[0] = L2TP_SEQUENCE_BIT;
skb->data[6] = opt->sequence >> 8;
skb->data[7] = opt->sequence;
skb->data[8] = 0;
skb->data[1] = L2TP_VERSION;
unaligned(&skb->data[2])->u32 = opt->remote;
- /* Now send the packet via UDP socket. */
- iov.iov_base = skb->data;
- iov.iov_len = skb->len;
- kernel_sendmsg(sk_udp->sk_socket, &msg, &iov, 1, skb->len);
- kfree_skb(skb);
+ /* Now send the packet via the delivery queue. */
+ skb_set_owner_w(skb, sk_udp);
+ skb_queue_tail(&delivery_queue, skb);
+ schedule_work(&delivery_work);
return 1;
}
error = -EBUSY;
if (udp_sk(sk_udp)->encap_type || sk_udp->sk_user_data)
goto out;
+ if (!sk_udp->sk_bound_dev_if) {
+ struct dst_entry *dst = sk_dst_get(sk_udp);
+ error = -ENODEV;
+ if (!dst)
+ goto out;
+ sk_udp->sk_bound_dev_if = dst->dev->ifindex;
+ dst_release(dst);
+ }
po->chan.hdrlen = 12;
po->chan.private = sk_udp;
po->chan.mtu = PPP_MTU - 80;
po->proto.lac.local = unaligned(&addr->local)->u32;
po->proto.lac.remote = unaligned(&addr->remote)->u32;
+ po->proto.lac.backlog_rcv = sk_udp->sk_backlog_rcv;
error = ppp_register_channel(&po->chan);
if (error)
sk->sk_state = PPPOX_CONNECTED;
udp_sk(sk_udp)->encap_type = UDP_ENCAP_L2TPINUDP;
udp_sk(sk_udp)->encap_rcv = pppolac_recv;
+ sk_udp->sk_backlog_rcv = pppolac_recv_core;
sk_udp->sk_user_data = sk;
-
out:
if (sock_udp) {
release_sock(sk_udp);
if (sk->sk_state != PPPOX_NONE) {
struct sock *sk_udp = (struct sock *)pppox_sk(sk)->chan.private;
lock_sock(sk_udp);
-
pppox_unbind_sock(sk);
- sk_udp->sk_user_data = NULL;
udp_sk(sk_udp)->encap_type = 0;
udp_sk(sk_udp)->encap_rcv = NULL;
-
+ sk_udp->sk_backlog_rcv = pppox_sk(sk)->proto.lac.backlog_rcv;
+ sk_udp->sk_user_data = NULL;
release_sock(sk_udp);
sockfd_put(sk_udp->sk_socket);
}
error = register_pppox_proto(PX_PROTO_OLAC, &pppolac_pppox_proto);
if (error)
proto_unregister(&pppolac_proto);
+ else
+ skb_queue_head_init(&delivery_queue);
return error;
}
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