+++ /dev/null
-/* drivers/net/pppolac.c
- *
- * 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
- * may be copied, distributed, and modified under those terms.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
- * GNU General Public License for more details.
- */
-
-/* This driver handles L2TP data packets between a UDP socket and a PPP channel.
- * To keep things simple, only one session per socket is permitted. Packets are
- * sent via the socket, so it must keep connected to the same address. One must
- * not set sequencing in ICCN but let LNS controll it. Currently this driver
- * only works on IPv4 due to the lack of UDP encapsulation support in IPv6. */
-
-#include <linux/module.h>
-#include <linux/skbuff.h>
-#include <linux/file.h>
-#include <linux/net.h>
-#include <linux/udp.h>
-#include <linux/ppp_defs.h>
-#include <linux/if_ppp.h>
-#include <linux/if_pppox.h>
-#include <linux/ppp_channel.h>
-#include <net/tcp_states.h>
-
-#define L2TP_CONTROL_MASK 0x80
-#define L2TP_VERSION_MASK 0x0F
-#define L2TP_VERSION 0x02
-#define L2TP_LENGTH_MASK 0x40
-#define L2TP_OFFSET_MASK 0x02
-#define L2TP_SEQUENCE_MASK 0x08
-
-#define PPP_ADDR 0xFF
-#define PPP_CTRL 0x03
-
-union unaligned {
- __u32 u32;
-} __attribute__((packed));
-
-static inline union unaligned *unaligned(void *ptr)
-{
- return (union unaligned *)ptr;
-}
-
-static int pppolac_recv(struct sock *sk_udp, struct sk_buff *skb)
-{
- struct sock *sk;
- struct pppolac_opt *opt;
- __u8 bits;
- __u8 *ptr;
-
- /* Drop the packet if it is too short. */
- if (skb->len < sizeof(struct udphdr) + 6)
- goto drop;
-
- /* Put it back if it is a control packet. */
- if (skb->data[sizeof(struct udphdr)] & L2TP_CONTROL_MASK)
- return 1;
-
- /* Now the packet is ours. Skip UDP header. */
- skb_pull(skb, sizeof(struct udphdr));
-
- /* Check the version. */
- if ((skb->data[1] & L2TP_VERSION_MASK) != L2TP_VERSION)
- goto drop;
- bits = skb->data[0];
- ptr = &skb->data[2];
-
- /* Check the length if it is present. */
- if (bits & L2TP_LENGTH_MASK) {
- 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)))
- goto drop;
-
- /* Skip the offset padding if it is present. */
- if (bits & L2TP_OFFSET_MASK &&
- !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);
- 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;
-
- /* Skip PPP address and control if they are present. */
- if (skb->len >= 2 && skb->data[0] == PPP_ADDR &&
- skb->data[1] == PPP_CTRL)
- skb_pull(skb, 2);
-
- /* Fix PPP protocol if it is compressed. */
- 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(). */
- skb_orphan(skb);
- lock_sock(sk);
- ppp_input(&pppox_sk(sk)->chan, skb);
- release_sock(sk);
- sock_put(sk);
- return 0;
-
-drop:
- kfree_skb(skb);
- return 0;
-}
-
-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);
- skb->data[0] = PPP_ADDR;
- skb->data[1] = PPP_CTRL;
-
- /* Install L2TP header. */
- if (opt->sequencing) {
- skb_push(skb, 10);
- skb->data[0] = L2TP_SEQUENCE_MASK;
- skb->data[6] = opt->sequence >> 8;
- skb->data[7] = opt->sequence;
- skb->data[8] = 0;
- skb->data[9] = 0;
- opt->sequence++;
- } else {
- skb_push(skb, 6);
- skb->data[0] = 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);
- return 1;
-}
-
-/******************************************************************************/
-
-static struct ppp_channel_ops pppolac_channel_ops = {
- .start_xmit = pppolac_xmit,
-};
-
-static int pppolac_connect(struct socket *sock, struct sockaddr *useraddr,
- int addrlen, int flags)
-{
- struct sock *sk = sock->sk;
- struct pppox_sock *po = pppox_sk(sk);
- struct sockaddr_pppolac *addr = (struct sockaddr_pppolac *)useraddr;
- struct socket *sock_udp = NULL;
- struct sock *sk_udp;
- int error;
-
- if (addrlen != sizeof(struct sockaddr_pppolac) ||
- !addr->local.tunnel || !addr->local.session ||
- !addr->remote.tunnel || !addr->remote.session) {
- return -EINVAL;
- }
-
- lock_sock(sk);
- error = -EALREADY;
- if (sk->sk_state != PPPOX_NONE)
- goto out;
-
- sock_udp = sockfd_lookup(addr->udp_socket, &error);
- if (!sock_udp)
- goto out;
- sk_udp = sock_udp->sk;
- lock_sock(sk_udp);
-
- /* Remove this check when IPv6 supports UDP encapsulation. */
- error = -EAFNOSUPPORT;
- if (sk_udp->sk_family != AF_INET)
- goto out;
- error = -EPROTONOSUPPORT;
- if (sk_udp->sk_protocol != IPPROTO_UDP)
- goto out;
- error = -EDESTADDRREQ;
- if (sk_udp->sk_state != TCP_ESTABLISHED)
- goto out;
- error = -EBUSY;
- if (udp_sk(sk_udp)->encap_type || sk_udp->sk_user_data)
- goto out;
-
- po->chan.hdrlen = 12;
- po->chan.private = sk_udp;
- po->chan.ops = &pppolac_channel_ops;
- po->chan.mtu = PPP_MTU - 80;
- po->proto.lac.local = unaligned(&addr->local)->u32;
- po->proto.lac.remote = unaligned(&addr->remote)->u32;
-
- error = ppp_register_channel(&po->chan);
- if (error)
- goto out;
-
- 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_user_data = sk;
-
-out:
- if (sock_udp) {
- release_sock(sk_udp);
- if (error)
- sockfd_put(sock_udp);
- }
- release_sock(sk);
- return error;
-}
-
-static int pppolac_release(struct socket *sock)
-{
- struct sock *sk = sock->sk;
-
- if (!sk)
- return 0;
-
- lock_sock(sk);
- if (sock_flag(sk, SOCK_DEAD)) {
- release_sock(sk);
- return -EBADF;
- }
-
- 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;
-
- release_sock(sk_udp);
- sockfd_put(sk_udp->sk_socket);
- }
-
- sock_orphan(sk);
- sock->sk = NULL;
- release_sock(sk);
- sock_put(sk);
- return 0;
-}
-
-/******************************************************************************/
-
-static struct proto pppolac_proto = {
- .name = "PPPOLAC",
- .owner = THIS_MODULE,
- .obj_size = sizeof(struct pppox_sock),
-};
-
-static struct proto_ops pppolac_proto_ops = {
- .family = PF_PPPOX,
- .owner = THIS_MODULE,
- .release = pppolac_release,
- .bind = sock_no_bind,
- .connect = pppolac_connect,
- .socketpair = sock_no_socketpair,
- .accept = sock_no_accept,
- .getname = sock_no_getname,
- .poll = sock_no_poll,
- .ioctl = pppox_ioctl,
- .listen = sock_no_listen,
- .shutdown = sock_no_shutdown,
- .setsockopt = sock_no_setsockopt,
- .getsockopt = sock_no_getsockopt,
- .sendmsg = sock_no_sendmsg,
- .recvmsg = sock_no_recvmsg,
- .mmap = sock_no_mmap,
-};
-
-static int pppolac_create(struct net *net, struct socket *sock)
-{
- struct sock *sk;
-
- sk = sk_alloc(net, PF_PPPOX, GFP_KERNEL, &pppolac_proto);
- if (!sk)
- return -ENOMEM;
-
- sock_init_data(sock, sk);
- sock->state = SS_UNCONNECTED;
- sock->ops = &pppolac_proto_ops;
- sk->sk_protocol = PX_PROTO_OLAC;
- sk->sk_state = PPPOX_NONE;
- return 0;
-}
-
-/******************************************************************************/
-
-static struct pppox_proto pppolac_pppox_proto = {
- .create = pppolac_create,
- .owner = THIS_MODULE,
-};
-
-static int __init pppolac_init(void)
-{
- int error;
-
- error = proto_register(&pppolac_proto, 0);
- if (error)
- return error;
-
- error = register_pppox_proto(PX_PROTO_OLAC, &pppolac_pppox_proto);
- if (error)
- proto_unregister(&pppolac_proto);
- return error;
-}
-
-static void __exit pppolac_exit(void)
-{
- unregister_pppox_proto(PX_PROTO_OLAC);
- proto_unregister(&pppolac_proto);
-}
-
-module_init(pppolac_init);
-module_exit(pppolac_exit);
-
-MODULE_DESCRIPTION("PPP on L2TP Access Concentrator (PPPoLAC)");
-MODULE_AUTHOR("Chia-chi Yeh <chiachi@android.com>");
-MODULE_LICENSE("GPL");
projects / firefly-linux-kernel-4.4.55.git / commitdiff