Add PPTP support in mtpd.
If control socket does not exist, parse arguments from command line.
diff --git a/Android.mk b/Android.mk
index 78c5763..b0fd843 100644
--- a/Android.mk
+++ b/Android.mk
@@ -19,7 +19,7 @@
LOCAL_PATH := $(call my-dir)
include $(CLEAR_VARS)
-LOCAL_SRC_FILES := mtpd.c l2tp.c
+LOCAL_SRC_FILES := mtpd.c l2tp.c pptp.c
LOCAL_SHARED_LIBRARIES := libcutils
LOCAL_CFLAGS := -DANDROID_CHANGES
diff --git a/mtpd.c b/mtpd.c
index 5a2492b..4a06f3b 100644
--- a/mtpd.c
+++ b/mtpd.c
@@ -39,7 +39,8 @@
int the_socket = -1;
extern struct protocol l2tp;
-static struct protocol *protocols[] = {&l2tp, NULL};
+extern struct protocol pptp;
+static struct protocol *protocols[] = {&l2tp, &pptp, NULL};
static struct protocol *the_protocol;
static int pppd_argc;
@@ -108,9 +109,11 @@
int control;
int i;
+ if ((i = android_get_control_socket("mtpd")) == -1) {
+ return -1;
+ }
log_print(DEBUG, "Waiting for control socket");
- i = android_get_control_socket("mtpd");
- if (i == -1 || listen(i, 1) == -1 || (control = accept(i, NULL, 0)) == -1) {
+ if (listen(i, 1) == -1 || (control = accept(i, NULL, 0)) == -1) {
log_print(FATAL, "Cannot get control socket");
exit(SYSTEM_ERROR);
}
diff --git a/pptp.c b/pptp.c
new file mode 100644
index 0000000..f749c5c
--- /dev/null
+++ b/pptp.c
@@ -0,0 +1,408 @@
+/*
+ * Copyright (C) 2009 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+/* A simple implementation of PPTP Network Server (RFC 2637) which only
+ * creates a single session. The following code only handles control packets.
+ * Data packets are handled by PPPoPNS driver which can be found in Android
+ * kernel tree. */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <errno.h>
+#include <sys/types.h>
+#include <sys/socket.h>
+#include <arpa/inet.h>
+#include <linux/if_pppopns.h>
+
+#include "mtpd.h"
+
+enum pptp_message {
+ SCCRQ = 1,
+ SCCRP = 2,
+ STOPCCRQ = 3,
+ STOPCCRP = 4,
+ ECHORQ = 5,
+ ECHORP = 6,
+ OCRQ = 7,
+ OCRP = 8,
+ ICRQ = 9,
+ ICRP = 10,
+ ICCN = 11,
+ CCRQ = 12,
+ CDN = 13,
+ WEN = 14,
+ SLI = 15,
+ MESSAGE_MAX = 15,
+};
+
+static char *messages[] = {
+ NULL, "SCCRQ", "SCCRP", "STOPCCRQ", "STOPCCRP", "ECHORQ", "ECHORP",
+ "OCRQ", "OCRP", "ICRQ", "ICRP", "ICCN", "CCRQ", "CDN", "WEN", "SLI",
+};
+
+static uint8_t lengths[] = {
+ 0, 156, 156, 16, 16, 16, 20, 168, 32, 220, 24, 28, 16, 148, 40, 24,
+};
+
+#define CONTROL_MESSAGE htons(1)
+#define MAGIC_COOKIE htonl(0x1A2B3C4D)
+#define PROTOCOL_VERSION htons(0x0100)
+
+#define RESULT_OK 1
+#define RESULT_ERROR 2
+
+/* Some implementation uses 0 instead of 1, so we allow both of them. */
+#define ESTABLISHED(result) (result <= 1)
+
+#define HEADER_SIZE 8
+#define MIN_MESSAGE_SIZE 10
+
+static uint16_t local;
+static uint16_t remote;
+static uint16_t state;
+
+#define MAX_PACKET_LENGTH 220
+
+/* We define all the fields we used in this structure. Type conversion and byte
+ * alignment are solved in one place. Although it looks a little bit ugly, it
+ * really makes life easier. */
+static struct packet {
+ int length;
+ int expect;
+ union {
+ uint8_t buffer[MAX_PACKET_LENGTH];
+ struct {
+ struct __attribute__((packed)) {
+ uint16_t length;
+ uint16_t type;
+ uint32_t cookie;
+ } header;
+ uint16_t message;
+ uint16_t reserved;
+ union {
+ struct __attribute__((packed)) {
+ uint16_t protocol_version;
+ uint8_t result;
+ uint8_t error;
+ uint32_t framing;
+ uint32_t bearer;
+ uint16_t channels;
+ uint16_t firmware_revision;
+ char host[64];
+ } sccrp, sccrq;
+ struct __attribute__((packed)) {
+ uint16_t call;
+ uint16_t serial;
+ uint32_t minimum_speed;
+ uint32_t maximum_speed;
+ uint32_t bearer;
+ uint32_t framing;
+ uint16_t window_size;
+ } ocrq;
+ struct __attribute__((packed)) {
+ uint16_t call;
+ uint16_t peer;
+ uint8_t result;
+ } ocrp, icrp;
+ struct __attribute__((packed)) {
+ uint32_t identifier;
+ uint8_t result;
+ } echorq, echorp;
+ struct __attribute__((packed)) {
+ uint16_t call;
+ } icrq, ccrq, cdn;
+ };
+ } __attribute__((packed));
+ } __attribute__((aligned(4)));
+} incoming, outgoing;
+
+static void set_message(uint16_t message)
+{
+ uint16_t length = lengths[message];
+ memset(outgoing.buffer, 0, length);
+ outgoing.length = length;
+ outgoing.header.length = htons(length);
+ outgoing.header.type = CONTROL_MESSAGE;
+ outgoing.header.cookie = MAGIC_COOKIE;
+ outgoing.message = htons(message);
+}
+
+static void send_packet()
+{
+ send(the_socket, outgoing.buffer, outgoing.length, 0);
+}
+
+static int recv_packet()
+{
+ int length;
+
+ /* We are going to read a new message if incoming.expect is 0. */
+ if (!incoming.expect) {
+ incoming.length = 0;
+ incoming.expect = HEADER_SIZE;
+ }
+
+ /* The longest message defined in RFC 2637 is 220 bytes, but the protocol
+ * itself allows up to 65536 bytes. Therefore we always read a complete
+ * message but only keep the first 220 bytes before passing up. */
+ length = incoming.expect - incoming.length;
+ if (incoming.length >= MAX_PACKET_LENGTH) {
+ uint8_t buffer[length];
+ length = recv(the_socket, buffer, length, 0);
+ } else {
+ if (incoming.expect > MAX_PACKET_LENGTH) {
+ length = MAX_PACKET_LENGTH - incoming.length;
+ }
+ length = recv(the_socket, &incoming.buffer[incoming.length], length, 0);
+ }
+ if (length == -1) {
+ if (errno == EINTR) {
+ return 0;
+ }
+ log_print(FATAL, "Recv() %s", strerror(errno));
+ exit(NETWORK_ERROR);
+ }
+ if (length == 0) {
+ log_print(DEBUG, "Connection closed");
+ log_print(INFO, "Remote server hung up");
+ return -REMOTE_REQUESTED;
+ }
+ incoming.length += length;
+
+ /* If incoming.header is valid, check cookie and update incoming.expect. */
+ if (incoming.length == HEADER_SIZE && incoming.expect == HEADER_SIZE) {
+ if (incoming.header.cookie != MAGIC_COOKIE) {
+ log_print(DEBUG, "Loss of synchronization");
+ log_print(ERROR, "Protocol error");
+ return -PROTOCOL_ERROR;
+ }
+ incoming.expect = ntohs(incoming.header.length);
+ if (incoming.expect < HEADER_SIZE) {
+ log_print(DEBUG, "Invalid message length");
+ log_print(ERROR, "Protocol error");
+ return -PROTOCOL_ERROR;
+ }
+ }
+
+ /* Now we have a complete message. Reset incoming.expect. */
+ if (incoming.length == incoming.expect) {
+ incoming.expect = 0;
+
+ /* Return 1 if it is a control message. */
+ if (incoming.header.type == CONTROL_MESSAGE) {
+ return 1;
+ }
+ log_print(DEBUG, "Ignored non-control message (type = %d)",
+ ntohs(incoming.header.type));
+ }
+ return 0;
+}
+
+static int pptp_connect(int argc, char **argv)
+{
+ if (argc < 2) {
+ return -USAGE_ERROR;
+ }
+ create_socket(AF_UNSPEC, SOCK_STREAM, argv[0], argv[1]);
+
+ log_print(DEBUG, "Sending SCCRQ");
+ state = SCCRQ;
+ set_message(SCCRQ);
+ outgoing.sccrq.protocol_version = PROTOCOL_VERSION;
+ outgoing.sccrq.framing = htonl(3);
+ outgoing.sccrq.bearer = htonl(3);
+ outgoing.sccrq.channels = htons(1);
+ strcpy(outgoing.sccrq.host, "anonymous");
+ send_packet();
+ return 0;
+}
+
+static int create_pppox()
+{
+ int pppox;
+ log_print(INFO, "Creating PPPoX socket");
+ pppox = socket(AF_PPPOX, SOCK_DGRAM, PX_PROTO_OPNS);
+
+ if (pppox == -1) {
+ log_print(FATAL, "Socket() %s", strerror(errno));
+ exit(SYSTEM_ERROR);
+ } else {
+ struct sockaddr_pppopns address = {
+ .sa_family = AF_PPPOX,
+ .sa_protocol = PX_PROTO_OPNS,
+ .tcp_socket = the_socket,
+ .local = local,
+ .remote = remote,
+ };
+ if (connect(pppox, (struct sockaddr *)&address, sizeof(address)) != 0) {
+ log_print(FATAL, "Connect() %s", strerror(errno));
+ exit(SYSTEM_ERROR);
+ }
+ }
+ return pppox;
+}
+
+static int pptp_process()
+{
+ int result = recv_packet();
+ if (result <= 0) {
+ return result;
+ }
+
+ if (incoming.length < MIN_MESSAGE_SIZE) {
+ log_print(DEBUG, "Control message too short");
+ return 0;
+ }
+ incoming.message = ntohs(incoming.message);
+ if (incoming.message > MESSAGE_MAX || !messages[incoming.message]) {
+ log_print(DEBUG, "Received UNKNOWN %d", incoming.message);
+ return 0;
+ }
+ if (incoming.length < lengths[incoming.message]) {
+ log_print(DEBUG, "Received %s with invalid length (length = %d)",
+ messages[incoming.message], incoming.length);
+ return 0;
+ }
+
+ switch(incoming.message) {
+ case SCCRP:
+ if (state == SCCRQ) {
+ if (incoming.sccrp.protocol_version == PROTOCOL_VERSION
+ && ESTABLISHED(incoming.sccrp.result)) {
+ while (!local) {
+ local = random();
+ }
+ log_print(DEBUG, "Received SCCRP -> Sending OCRQ "
+ "(local = %d)", local);
+ log_print(INFO, "Tunnel established");
+ state = OCRQ;
+ set_message(OCRQ);
+ outgoing.ocrq.call = local;
+ outgoing.ocrq.serial = random();
+ outgoing.ocrq.minimum_speed = htonl(1000);
+ outgoing.ocrq.maximum_speed = htonl(100000000);
+ outgoing.ocrq.bearer = htonl(3);
+ outgoing.ocrq.framing = htonl(3);
+ outgoing.ocrq.window_size = htons(8192);
+ send_packet();
+ return 0;
+ }
+ log_print(DEBUG, "Received SCCRP (result = %d)",
+ incoming.sccrq.result);
+ log_print(INFO, "Remote server hung up");
+ return -REMOTE_REQUESTED;
+ }
+ break;
+
+ case OCRP:
+ if (state == OCRQ && incoming.ocrp.peer == local) {
+ if (ESTABLISHED(incoming.ocrp.result)) {
+ remote = incoming.ocrp.call;
+ log_print(DEBUG, "Received OCRQ (remote = %d)", remote);
+ log_print(INFO, "Session established");
+ state = OCRP;
+ start_pppd(create_pppox());
+ return 0;
+ }
+ log_print(DEBUG, "Received OCRP (result = %d)",
+ incoming.ocrp.result);
+ log_print(INFO, "Remote server hung up");
+ return -REMOTE_REQUESTED;
+ }
+ break;
+
+ case STOPCCRQ:
+ log_print(DEBUG, "Received STOPCCRQ");
+ log_print(INFO, "Remote server hung up");
+ state = STOPCCRQ;
+ return -REMOTE_REQUESTED;
+
+ case CCRQ:
+ /* According to RFC 2637 page 45, we should never receive CCRQ for
+ * outgoing calls. However, some implementation only acts as PNS and
+ * always uses CCRQ to clear a call, so here we still handle it. */
+ if (state == OCRP && incoming.ccrq.call == remote) {
+ log_print(DEBUG, "Received CCRQ (remote = %d)", remote);
+ log_print(INFO, "Remote server hung up");
+ return -REMOTE_REQUESTED;
+ }
+ break;
+
+ case CDN:
+ if (state == OCRP && incoming.cdn.call == remote) {
+ log_print(DEBUG, "Received CDN (remote = %d)", remote);
+ log_print(INFO, "Remote server hung up");
+ return -REMOTE_REQUESTED;
+ }
+ break;
+
+ case ECHORQ:
+ log_print(DEBUG, "Received ECHORQ -> Sending ECHORP");
+ set_message(ECHORP);
+ outgoing.echorp.identifier = incoming.echorq.identifier;
+ outgoing.echorp.result = RESULT_OK;
+ send_packet();
+ return 0;
+
+ case WEN:
+ case SLI:
+ log_print(DEBUG, "Recevied %s", messages[incoming.message]);
+ return 0;
+
+ case ICRQ:
+ log_print(DEBUG, "Received ICRQ (remote = %d) -> Sending ICRP "
+ "with error", incoming.icrq.call);
+ set_message(ICRP);
+ outgoing.icrp.peer = incoming.icrq.call;
+ outgoing.icrp.result = RESULT_ERROR;
+ send_packet();
+ return 0;
+
+ case OCRQ:
+ log_print(DEBUG, "Received OCRQ (remote = %d) -> Sending OCRP "
+ "with error", incoming.ocrq.call);
+ set_message(OCRP);
+ outgoing.ocrp.peer = incoming.ocrq.call;
+ outgoing.ocrp.result = RESULT_ERROR;
+ send_packet();
+ return 0;
+ }
+
+ /* We reach here if we got an unexpected message. Just log it. */
+ log_print(DEBUG, "Received UNEXPECTED %s", messages[incoming.message]);
+ return 0;
+}
+
+static int pptp_timeout()
+{
+ return 0;
+}
+
+static void pptp_shutdown()
+{
+ /* Normally we should send STOPCCRQ and wait for STOPCCRP, but this might
+ * block for a long time. Here we simply take the shortcut: do nothing. */
+}
+
+struct protocol pptp = {
+ .name = "pptp",
+ .usage = "<server> <port>",
+ .connect = pptp_connect,
+ .process = pptp_process,
+ .timeout = pptp_timeout,
+ .shutdown = pptp_shutdown,
+};
