v4.19.13 snapshot.
diff --git a/drivers/net/ppp/pptp.c b/drivers/net/ppp/pptp.c
new file mode 100644
index 0000000..67ffe74
--- /dev/null
+++ b/drivers/net/ppp/pptp.c
@@ -0,0 +1,699 @@
+/*
+ * Point-to-Point Tunneling Protocol for Linux
+ *
+ * Authors: Dmitry Kozlov <xeb@mail.ru>
+ *
+ * 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.
+ *
+ */
+
+#include <linux/string.h>
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/slab.h>
+#include <linux/errno.h>
+#include <linux/netdevice.h>
+#include <linux/net.h>
+#include <linux/skbuff.h>
+#include <linux/vmalloc.h>
+#include <linux/init.h>
+#include <linux/ppp_channel.h>
+#include <linux/ppp_defs.h>
+#include <linux/if_pppox.h>
+#include <linux/ppp-ioctl.h>
+#include <linux/notifier.h>
+#include <linux/file.h>
+#include <linux/in.h>
+#include <linux/ip.h>
+#include <linux/rcupdate.h>
+#include <linux/spinlock.h>
+
+#include <net/sock.h>
+#include <net/protocol.h>
+#include <net/ip.h>
+#include <net/icmp.h>
+#include <net/route.h>
+#include <net/gre.h>
+#include <net/pptp.h>
+
+#include <linux/uaccess.h>
+
+#define PPTP_DRIVER_VERSION "0.8.5"
+
+#define MAX_CALLID 65535
+
+static DECLARE_BITMAP(callid_bitmap, MAX_CALLID + 1);
+static struct pppox_sock __rcu **callid_sock;
+
+static DEFINE_SPINLOCK(chan_lock);
+
+static struct proto pptp_sk_proto __read_mostly;
+static const struct ppp_channel_ops pptp_chan_ops;
+static const struct proto_ops pptp_ops;
+
+static struct pppox_sock *lookup_chan(u16 call_id, __be32 s_addr)
+{
+ struct pppox_sock *sock;
+ struct pptp_opt *opt;
+
+ rcu_read_lock();
+ sock = rcu_dereference(callid_sock[call_id]);
+ if (sock) {
+ opt = &sock->proto.pptp;
+ if (opt->dst_addr.sin_addr.s_addr != s_addr)
+ sock = NULL;
+ else
+ sock_hold(sk_pppox(sock));
+ }
+ rcu_read_unlock();
+
+ return sock;
+}
+
+static int lookup_chan_dst(u16 call_id, __be32 d_addr)
+{
+ struct pppox_sock *sock;
+ struct pptp_opt *opt;
+ int i;
+
+ rcu_read_lock();
+ i = 1;
+ for_each_set_bit_from(i, callid_bitmap, MAX_CALLID) {
+ sock = rcu_dereference(callid_sock[i]);
+ if (!sock)
+ continue;
+ opt = &sock->proto.pptp;
+ if (opt->dst_addr.call_id == call_id &&
+ opt->dst_addr.sin_addr.s_addr == d_addr)
+ break;
+ }
+ rcu_read_unlock();
+
+ return i < MAX_CALLID;
+}
+
+static int add_chan(struct pppox_sock *sock,
+ struct pptp_addr *sa)
+{
+ static int call_id;
+
+ spin_lock(&chan_lock);
+ if (!sa->call_id) {
+ call_id = find_next_zero_bit(callid_bitmap, MAX_CALLID, call_id + 1);
+ if (call_id == MAX_CALLID) {
+ call_id = find_next_zero_bit(callid_bitmap, MAX_CALLID, 1);
+ if (call_id == MAX_CALLID)
+ goto out_err;
+ }
+ sa->call_id = call_id;
+ } else if (test_bit(sa->call_id, callid_bitmap)) {
+ goto out_err;
+ }
+
+ sock->proto.pptp.src_addr = *sa;
+ set_bit(sa->call_id, callid_bitmap);
+ rcu_assign_pointer(callid_sock[sa->call_id], sock);
+ spin_unlock(&chan_lock);
+
+ return 0;
+
+out_err:
+ spin_unlock(&chan_lock);
+ return -1;
+}
+
+static void del_chan(struct pppox_sock *sock)
+{
+ spin_lock(&chan_lock);
+ clear_bit(sock->proto.pptp.src_addr.call_id, callid_bitmap);
+ RCU_INIT_POINTER(callid_sock[sock->proto.pptp.src_addr.call_id], NULL);
+ spin_unlock(&chan_lock);
+}
+
+static int pptp_xmit(struct ppp_channel *chan, struct sk_buff *skb)
+{
+ struct sock *sk = (struct sock *) chan->private;
+ struct pppox_sock *po = pppox_sk(sk);
+ struct net *net = sock_net(sk);
+ struct pptp_opt *opt = &po->proto.pptp;
+ struct pptp_gre_header *hdr;
+ unsigned int header_len = sizeof(*hdr);
+ struct flowi4 fl4;
+ int islcp;
+ int len;
+ unsigned char *data;
+ __u32 seq_recv;
+
+
+ struct rtable *rt;
+ struct net_device *tdev;
+ struct iphdr *iph;
+ int max_headroom;
+
+ if (sk_pppox(po)->sk_state & PPPOX_DEAD)
+ goto tx_error;
+
+ rt = ip_route_output_ports(net, &fl4, NULL,
+ opt->dst_addr.sin_addr.s_addr,
+ opt->src_addr.sin_addr.s_addr,
+ 0, 0, IPPROTO_GRE,
+ RT_TOS(0), 0);
+ if (IS_ERR(rt))
+ goto tx_error;
+
+ tdev = rt->dst.dev;
+
+ max_headroom = LL_RESERVED_SPACE(tdev) + sizeof(*iph) + sizeof(*hdr) + 2;
+
+ if (skb_headroom(skb) < max_headroom || skb_cloned(skb) || skb_shared(skb)) {
+ struct sk_buff *new_skb = skb_realloc_headroom(skb, max_headroom);
+ if (!new_skb) {
+ ip_rt_put(rt);
+ goto tx_error;
+ }
+ if (skb->sk)
+ skb_set_owner_w(new_skb, skb->sk);
+ consume_skb(skb);
+ skb = new_skb;
+ }
+
+ data = skb->data;
+ islcp = ((data[0] << 8) + data[1]) == PPP_LCP && 1 <= data[2] && data[2] <= 7;
+
+ /* compress protocol field */
+ if ((opt->ppp_flags & SC_COMP_PROT) && data[0] == 0 && !islcp)
+ skb_pull(skb, 1);
+
+ /* Put in the address/control bytes if necessary */
+ if ((opt->ppp_flags & SC_COMP_AC) == 0 || islcp) {
+ data = skb_push(skb, 2);
+ data[0] = PPP_ALLSTATIONS;
+ data[1] = PPP_UI;
+ }
+
+ len = skb->len;
+
+ seq_recv = opt->seq_recv;
+
+ if (opt->ack_sent == seq_recv)
+ header_len -= sizeof(hdr->ack);
+
+ /* Push down and install GRE header */
+ skb_push(skb, header_len);
+ hdr = (struct pptp_gre_header *)(skb->data);
+
+ hdr->gre_hd.flags = GRE_KEY | GRE_VERSION_1 | GRE_SEQ;
+ hdr->gre_hd.protocol = GRE_PROTO_PPP;
+ hdr->call_id = htons(opt->dst_addr.call_id);
+
+ hdr->seq = htonl(++opt->seq_sent);
+ if (opt->ack_sent != seq_recv) {
+ /* send ack with this message */
+ hdr->gre_hd.flags |= GRE_ACK;
+ hdr->ack = htonl(seq_recv);
+ opt->ack_sent = seq_recv;
+ }
+ hdr->payload_len = htons(len);
+
+ /* Push down and install the IP header. */
+
+ skb_reset_transport_header(skb);
+ skb_push(skb, sizeof(*iph));
+ skb_reset_network_header(skb);
+ memset(&(IPCB(skb)->opt), 0, sizeof(IPCB(skb)->opt));
+ IPCB(skb)->flags &= ~(IPSKB_XFRM_TUNNEL_SIZE | IPSKB_XFRM_TRANSFORMED | IPSKB_REROUTED);
+
+ iph = ip_hdr(skb);
+ iph->version = 4;
+ iph->ihl = sizeof(struct iphdr) >> 2;
+ if (ip_dont_fragment(sk, &rt->dst))
+ iph->frag_off = htons(IP_DF);
+ else
+ iph->frag_off = 0;
+ iph->protocol = IPPROTO_GRE;
+ iph->tos = 0;
+ iph->daddr = fl4.daddr;
+ iph->saddr = fl4.saddr;
+ iph->ttl = ip4_dst_hoplimit(&rt->dst);
+ iph->tot_len = htons(skb->len);
+
+ skb_dst_drop(skb);
+ skb_dst_set(skb, &rt->dst);
+
+ nf_reset(skb);
+
+ skb->ip_summed = CHECKSUM_NONE;
+ ip_select_ident(net, skb, NULL);
+ ip_send_check(iph);
+
+ ip_local_out(net, skb->sk, skb);
+ return 1;
+
+tx_error:
+ kfree_skb(skb);
+ return 1;
+}
+
+static int pptp_rcv_core(struct sock *sk, struct sk_buff *skb)
+{
+ struct pppox_sock *po = pppox_sk(sk);
+ struct pptp_opt *opt = &po->proto.pptp;
+ int headersize, payload_len, seq;
+ __u8 *payload;
+ struct pptp_gre_header *header;
+
+ if (!(sk->sk_state & PPPOX_CONNECTED)) {
+ if (sock_queue_rcv_skb(sk, skb))
+ goto drop;
+ return NET_RX_SUCCESS;
+ }
+
+ header = (struct pptp_gre_header *)(skb->data);
+ headersize = sizeof(*header);
+
+ /* test if acknowledgement present */
+ if (GRE_IS_ACK(header->gre_hd.flags)) {
+ __u32 ack;
+
+ if (!pskb_may_pull(skb, headersize))
+ goto drop;
+ header = (struct pptp_gre_header *)(skb->data);
+
+ /* ack in different place if S = 0 */
+ ack = GRE_IS_SEQ(header->gre_hd.flags) ? header->ack : header->seq;
+
+ ack = ntohl(ack);
+
+ if (ack > opt->ack_recv)
+ opt->ack_recv = ack;
+ /* also handle sequence number wrap-around */
+ if (WRAPPED(ack, opt->ack_recv))
+ opt->ack_recv = ack;
+ } else {
+ headersize -= sizeof(header->ack);
+ }
+ /* test if payload present */
+ if (!GRE_IS_SEQ(header->gre_hd.flags))
+ goto drop;
+
+ payload_len = ntohs(header->payload_len);
+ seq = ntohl(header->seq);
+
+ /* check for incomplete packet (length smaller than expected) */
+ if (!pskb_may_pull(skb, headersize + payload_len))
+ goto drop;
+
+ payload = skb->data + headersize;
+ /* check for expected sequence number */
+ if (seq < opt->seq_recv + 1 || WRAPPED(opt->seq_recv, seq)) {
+ if ((payload[0] == PPP_ALLSTATIONS) && (payload[1] == PPP_UI) &&
+ (PPP_PROTOCOL(payload) == PPP_LCP) &&
+ ((payload[4] == PPP_LCP_ECHOREQ) || (payload[4] == PPP_LCP_ECHOREP)))
+ goto allow_packet;
+ } else {
+ opt->seq_recv = seq;
+allow_packet:
+ skb_pull(skb, headersize);
+
+ if (payload[0] == PPP_ALLSTATIONS && payload[1] == PPP_UI) {
+ /* chop off address/control */
+ if (skb->len < 3)
+ goto drop;
+ skb_pull(skb, 2);
+ }
+
+ if ((*skb->data) & 1) {
+ /* protocol is compressed */
+ *(u8 *)skb_push(skb, 1) = 0;
+ }
+
+ skb->ip_summed = CHECKSUM_NONE;
+ skb_set_network_header(skb, skb->head-skb->data);
+ ppp_input(&po->chan, skb);
+
+ return NET_RX_SUCCESS;
+ }
+drop:
+ kfree_skb(skb);
+ return NET_RX_DROP;
+}
+
+static int pptp_rcv(struct sk_buff *skb)
+{
+ struct pppox_sock *po;
+ struct pptp_gre_header *header;
+ struct iphdr *iph;
+
+ if (skb->pkt_type != PACKET_HOST)
+ goto drop;
+
+ if (!pskb_may_pull(skb, 12))
+ goto drop;
+
+ iph = ip_hdr(skb);
+
+ header = (struct pptp_gre_header *)skb->data;
+
+ if (header->gre_hd.protocol != GRE_PROTO_PPP || /* PPTP-GRE protocol for PPTP */
+ GRE_IS_CSUM(header->gre_hd.flags) || /* flag CSUM should be clear */
+ GRE_IS_ROUTING(header->gre_hd.flags) || /* flag ROUTING should be clear */
+ !GRE_IS_KEY(header->gre_hd.flags) || /* flag KEY should be set */
+ (header->gre_hd.flags & GRE_FLAGS)) /* flag Recursion Ctrl should be clear */
+ /* if invalid, discard this packet */
+ goto drop;
+
+ po = lookup_chan(htons(header->call_id), iph->saddr);
+ if (po) {
+ skb_dst_drop(skb);
+ nf_reset(skb);
+ return sk_receive_skb(sk_pppox(po), skb, 0);
+ }
+drop:
+ kfree_skb(skb);
+ return NET_RX_DROP;
+}
+
+static int pptp_bind(struct socket *sock, struct sockaddr *uservaddr,
+ int sockaddr_len)
+{
+ struct sock *sk = sock->sk;
+ struct sockaddr_pppox *sp = (struct sockaddr_pppox *) uservaddr;
+ struct pppox_sock *po = pppox_sk(sk);
+ int error = 0;
+
+ if (sockaddr_len < sizeof(struct sockaddr_pppox))
+ return -EINVAL;
+
+ lock_sock(sk);
+
+ if (sk->sk_state & PPPOX_DEAD) {
+ error = -EALREADY;
+ goto out;
+ }
+
+ if (sk->sk_state & PPPOX_BOUND) {
+ error = -EBUSY;
+ goto out;
+ }
+
+ if (add_chan(po, &sp->sa_addr.pptp))
+ error = -EBUSY;
+ else
+ sk->sk_state |= PPPOX_BOUND;
+
+out:
+ release_sock(sk);
+ return error;
+}
+
+static int pptp_connect(struct socket *sock, struct sockaddr *uservaddr,
+ int sockaddr_len, int flags)
+{
+ struct sock *sk = sock->sk;
+ struct sockaddr_pppox *sp = (struct sockaddr_pppox *) uservaddr;
+ struct pppox_sock *po = pppox_sk(sk);
+ struct pptp_opt *opt = &po->proto.pptp;
+ struct rtable *rt;
+ struct flowi4 fl4;
+ int error = 0;
+
+ if (sockaddr_len < sizeof(struct sockaddr_pppox))
+ return -EINVAL;
+
+ if (sp->sa_protocol != PX_PROTO_PPTP)
+ return -EINVAL;
+
+ if (lookup_chan_dst(sp->sa_addr.pptp.call_id, sp->sa_addr.pptp.sin_addr.s_addr))
+ return -EALREADY;
+
+ lock_sock(sk);
+ /* Check for already bound sockets */
+ if (sk->sk_state & PPPOX_CONNECTED) {
+ error = -EBUSY;
+ goto end;
+ }
+
+ /* Check for already disconnected sockets, on attempts to disconnect */
+ if (sk->sk_state & PPPOX_DEAD) {
+ error = -EALREADY;
+ goto end;
+ }
+
+ if (!opt->src_addr.sin_addr.s_addr || !sp->sa_addr.pptp.sin_addr.s_addr) {
+ error = -EINVAL;
+ goto end;
+ }
+
+ po->chan.private = sk;
+ po->chan.ops = &pptp_chan_ops;
+
+ rt = ip_route_output_ports(sock_net(sk), &fl4, sk,
+ opt->dst_addr.sin_addr.s_addr,
+ opt->src_addr.sin_addr.s_addr,
+ 0, 0,
+ IPPROTO_GRE, RT_CONN_FLAGS(sk), 0);
+ if (IS_ERR(rt)) {
+ error = -EHOSTUNREACH;
+ goto end;
+ }
+ sk_setup_caps(sk, &rt->dst);
+
+ po->chan.mtu = dst_mtu(&rt->dst);
+ if (!po->chan.mtu)
+ po->chan.mtu = PPP_MRU;
+ po->chan.mtu -= PPTP_HEADER_OVERHEAD;
+
+ po->chan.hdrlen = 2 + sizeof(struct pptp_gre_header);
+ error = ppp_register_channel(&po->chan);
+ if (error) {
+ pr_err("PPTP: failed to register PPP channel (%d)\n", error);
+ goto end;
+ }
+
+ opt->dst_addr = sp->sa_addr.pptp;
+ sk->sk_state |= PPPOX_CONNECTED;
+
+ end:
+ release_sock(sk);
+ return error;
+}
+
+static int pptp_getname(struct socket *sock, struct sockaddr *uaddr,
+ int peer)
+{
+ int len = sizeof(struct sockaddr_pppox);
+ struct sockaddr_pppox sp;
+
+ memset(&sp.sa_addr, 0, sizeof(sp.sa_addr));
+
+ sp.sa_family = AF_PPPOX;
+ sp.sa_protocol = PX_PROTO_PPTP;
+ sp.sa_addr.pptp = pppox_sk(sock->sk)->proto.pptp.src_addr;
+
+ memcpy(uaddr, &sp, len);
+
+ return len;
+}
+
+static int pptp_release(struct socket *sock)
+{
+ struct sock *sk = sock->sk;
+ struct pppox_sock *po;
+ int error = 0;
+
+ if (!sk)
+ return 0;
+
+ lock_sock(sk);
+
+ if (sock_flag(sk, SOCK_DEAD)) {
+ release_sock(sk);
+ return -EBADF;
+ }
+
+ po = pppox_sk(sk);
+ del_chan(po);
+ synchronize_rcu();
+
+ pppox_unbind_sock(sk);
+ sk->sk_state = PPPOX_DEAD;
+
+ sock_orphan(sk);
+ sock->sk = NULL;
+
+ release_sock(sk);
+ sock_put(sk);
+
+ return error;
+}
+
+static void pptp_sock_destruct(struct sock *sk)
+{
+ if (!(sk->sk_state & PPPOX_DEAD)) {
+ del_chan(pppox_sk(sk));
+ pppox_unbind_sock(sk);
+ }
+ skb_queue_purge(&sk->sk_receive_queue);
+}
+
+static int pptp_create(struct net *net, struct socket *sock, int kern)
+{
+ int error = -ENOMEM;
+ struct sock *sk;
+ struct pppox_sock *po;
+ struct pptp_opt *opt;
+
+ sk = sk_alloc(net, PF_PPPOX, GFP_KERNEL, &pptp_sk_proto, kern);
+ if (!sk)
+ goto out;
+
+ sock_init_data(sock, sk);
+
+ sock->state = SS_UNCONNECTED;
+ sock->ops = &pptp_ops;
+
+ sk->sk_backlog_rcv = pptp_rcv_core;
+ sk->sk_state = PPPOX_NONE;
+ sk->sk_type = SOCK_STREAM;
+ sk->sk_family = PF_PPPOX;
+ sk->sk_protocol = PX_PROTO_PPTP;
+ sk->sk_destruct = pptp_sock_destruct;
+
+ po = pppox_sk(sk);
+ opt = &po->proto.pptp;
+
+ opt->seq_sent = 0; opt->seq_recv = 0xffffffff;
+ opt->ack_recv = 0; opt->ack_sent = 0xffffffff;
+
+ error = 0;
+out:
+ return error;
+}
+
+static int pptp_ppp_ioctl(struct ppp_channel *chan, unsigned int cmd,
+ unsigned long arg)
+{
+ struct sock *sk = (struct sock *) chan->private;
+ struct pppox_sock *po = pppox_sk(sk);
+ struct pptp_opt *opt = &po->proto.pptp;
+ void __user *argp = (void __user *)arg;
+ int __user *p = argp;
+ int err, val;
+
+ err = -EFAULT;
+ switch (cmd) {
+ case PPPIOCGFLAGS:
+ val = opt->ppp_flags;
+ if (put_user(val, p))
+ break;
+ err = 0;
+ break;
+ case PPPIOCSFLAGS:
+ if (get_user(val, p))
+ break;
+ opt->ppp_flags = val & ~SC_RCV_BITS;
+ err = 0;
+ break;
+ default:
+ err = -ENOTTY;
+ }
+
+ return err;
+}
+
+static const struct ppp_channel_ops pptp_chan_ops = {
+ .start_xmit = pptp_xmit,
+ .ioctl = pptp_ppp_ioctl,
+};
+
+static struct proto pptp_sk_proto __read_mostly = {
+ .name = "PPTP",
+ .owner = THIS_MODULE,
+ .obj_size = sizeof(struct pppox_sock),
+};
+
+static const struct proto_ops pptp_ops = {
+ .family = AF_PPPOX,
+ .owner = THIS_MODULE,
+ .release = pptp_release,
+ .bind = pptp_bind,
+ .connect = pptp_connect,
+ .socketpair = sock_no_socketpair,
+ .accept = sock_no_accept,
+ .getname = pptp_getname,
+ .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,
+ .ioctl = pppox_ioctl,
+};
+
+static const struct pppox_proto pppox_pptp_proto = {
+ .create = pptp_create,
+ .owner = THIS_MODULE,
+};
+
+static const struct gre_protocol gre_pptp_protocol = {
+ .handler = pptp_rcv,
+};
+
+static int __init pptp_init_module(void)
+{
+ int err = 0;
+ pr_info("PPTP driver version " PPTP_DRIVER_VERSION "\n");
+
+ callid_sock = vzalloc(array_size(sizeof(void *), (MAX_CALLID + 1)));
+ if (!callid_sock)
+ return -ENOMEM;
+
+ err = gre_add_protocol(&gre_pptp_protocol, GREPROTO_PPTP);
+ if (err) {
+ pr_err("PPTP: can't add gre protocol\n");
+ goto out_mem_free;
+ }
+
+ err = proto_register(&pptp_sk_proto, 0);
+ if (err) {
+ pr_err("PPTP: can't register sk_proto\n");
+ goto out_gre_del_protocol;
+ }
+
+ err = register_pppox_proto(PX_PROTO_PPTP, &pppox_pptp_proto);
+ if (err) {
+ pr_err("PPTP: can't register pppox_proto\n");
+ goto out_unregister_sk_proto;
+ }
+
+ return 0;
+
+out_unregister_sk_proto:
+ proto_unregister(&pptp_sk_proto);
+out_gre_del_protocol:
+ gre_del_protocol(&gre_pptp_protocol, GREPROTO_PPTP);
+out_mem_free:
+ vfree(callid_sock);
+
+ return err;
+}
+
+static void __exit pptp_exit_module(void)
+{
+ unregister_pppox_proto(PX_PROTO_PPTP);
+ proto_unregister(&pptp_sk_proto);
+ gre_del_protocol(&gre_pptp_protocol, GREPROTO_PPTP);
+ vfree(callid_sock);
+}
+
+module_init(pptp_init_module);
+module_exit(pptp_exit_module);
+
+MODULE_DESCRIPTION("Point-to-Point Tunneling Protocol");
+MODULE_AUTHOR("D. Kozlov (xeb@mail.ru)");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS_NET_PF_PROTO(PF_PPPOX, PX_PROTO_PPTP);