diff options
Diffstat (limited to 'drivers/net')
| -rw-r--r-- | drivers/net/Kconfig | 9 | ||||
| -rw-r--r-- | drivers/net/Makefile | 1 | ||||
| -rw-r--r-- | drivers/net/pppolac.c | 359 |
3 files changed, 369 insertions, 0 deletions
diff --git a/drivers/net/Kconfig b/drivers/net/Kconfig index 19f04a3..5abe1b3 100644 --- a/drivers/net/Kconfig +++ b/drivers/net/Kconfig @@ -3323,6 +3323,15 @@ config PPPOL2TP used by ISPs and enterprises to tunnel PPP traffic over UDP tunnels. L2TP is replacing PPTP for VPN uses. +config PPPOLAC + tristate "PPP on L2TP Access Concentrator" + depends on PPP && INET + help + L2TP (RFC 2661) is a tunneling protocol widely used in virtual private + networks. This driver handles L2TP data packets between a UDP socket + and a PPP channel, but only permits one session per socket. Thus it is + fairly simple and suited for clients. + config SLIP tristate "SLIP (serial line) support" ---help--- diff --git a/drivers/net/Makefile b/drivers/net/Makefile index 776a478..77b94a0 100644 --- a/drivers/net/Makefile +++ b/drivers/net/Makefile @@ -168,6 +168,7 @@ obj-$(CONFIG_PPP_MPPE) += ppp_mppe.o obj-$(CONFIG_PPPOE) += pppox.o pppoe.o obj-$(CONFIG_PPPOL2TP) += pppox.o obj-$(CONFIG_PPTP) += pppox.o pptp.o +obj-$(CONFIG_PPPOLAC) += pppox.o pppolac.o obj-$(CONFIG_SLIP) += slip.o obj-$(CONFIG_SLHC) += slhc.o diff --git a/drivers/net/pppolac.c b/drivers/net/pppolac.c new file mode 100644 index 0000000..8843a9d --- /dev/null +++ b/drivers/net/pppolac.c @@ -0,0 +1,359 @@ +/* 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"); |