Merge changes from topic "pppolac"

* changes:
  pppd: Convert Android.mk to Android.bp
  pppd: Add rules for building the pppol2tp-android plugin
  pppd: Fix pppol2tp-android.so build
  pppd: Enable plugin support in pppd
  pppd: Add pppol2tp-android plugin
  pppd: Remove obsolete way of receiving args from mtpd

8 files changed, 291 insertions, 71 deletions

diff --git a/Android.bp b/Android.bp
new file mode 100644
index 0000000..3704241
--- /dev/null
+++ b/Android.bp
@@ -0,0 +1,15 @@
+// Copyright (C) 2018 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.
+
+subdirs = ["pppd"]
diff --git a/pppd/Android.bp b/pppd/Android.bp
new file mode 100644
index 0000000..d995a0d
--- /dev/null
+++ b/pppd/Android.bp
@@ -0,0 +1,88 @@
+// Copyright (C) 2018 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.
+
+cc_defaults {
+    name: "ppp_defaults",
+    cflags: [
+        "-DCHAPMS=1",
+        "-DMPPE=1",
+        "-DINET6=1",
+        "-DUSE_OPENSSL=1",
+        "-Wno-missing-field-initializers",
+        "-Wno-unused-parameter",
+        "-Werror",
+        "-Wno-pointer-sign",
+    ],
+    local_include_dirs: ["include"],
+}
+
+cc_binary {
+    name: "pppd",
+    defaults: ["ppp_defaults"],
+
+    srcs: [
+        "auth.c",
+        "ccp.c",
+        "chap-md5.c",
+        "chap-new.c",
+        "chap_ms.c",
+        "demand.c",
+        "eap.c",
+        "ecp.c",
+        "eui64.c",
+        "fsm.c",
+        "ipcp.c",
+        "ipv6cp.c",
+        "lcp.c",
+        "magic.c",
+        "main.c",
+        "options.c",
+        "pppcrypt.c",
+        "pppox.c",
+        "session.c",
+        "sys-linux.c",
+        "tty.c",
+        "upap.c",
+        "utils.c",
+    ],
+
+    // options.c:623:21: error: passing 'const char *' to parameter of
+    // type 'char *' discards qualifiers.
+    // [-Werror,-Wincompatible-pointer-types-discards-qualifiers]
+    clang_cflags: ["-Wno-incompatible-pointer-types-discards-qualifiers"],
+
+    shared_libs: [
+        "libdl",
+        "liblog",
+        "libcutils",
+        "libcrypto",
+    ],
+
+    cflags: [
+        "-Wno-empty-body",
+        "-Wno-attributes",
+        "-Wno-sign-compare",
+        "-DPLUGIN",
+    ],
+
+    ldflags: ["-rdynamic"],
+    required: ["pppol2tp-android"],
+}
+
+cc_library_shared {
+    name: "pppol2tp-android",
+    defaults: ["ppp_defaults"],
+    srcs: ["plugins/pppol2tp-android/pppol2tp-android.c"],
+    allow_undefined_symbols: true,
+}
diff --git a/pppd/Android.mk b/pppd/Android.mk
deleted file mode 100644
index 88cfe35..0000000
--- a/pppd/Android.mk
+++ /dev/null
@@ -1,46 +0,0 @@
-LOCAL_PATH:= $(call my-dir)
-include $(CLEAR_VARS)
-
-LOCAL_SRC_FILES:= \
-	auth.c \
-	ccp.c \
-	chap-md5.c \
-	chap-new.c \
-	chap_ms.c \
-	demand.c \
-	eap.c \
-	ecp.c \
-	eui64.c \
-	fsm.c \
-	ipcp.c \
-	ipv6cp.c \
-	lcp.c \
-	magic.c \
-	main.c \
-	options.c \
-	pppcrypt.c \
-	pppox.c \
-	session.c \
-	sys-linux.c \
-	tty.c \
-	upap.c \
-	utils.c
-
-# options.c:623:21: error: passing 'const char *' to parameter of type 'char *' discards qualifiers.
-# [-Werror,-Wincompatible-pointer-types-discards-qualifiers]
-LOCAL_CLANG_CFLAGS += -Wno-incompatible-pointer-types-discards-qualifiers
-
-LOCAL_SHARED_LIBRARIES := \
-	libcutils liblog libcrypto
-
-LOCAL_C_INCLUDES := \
-	$(LOCAL_PATH)/include
-
-LOCAL_CFLAGS := -DCHAPMS=1 -DMPPE=1 -DINET6=1 -DUSE_OPENSSL=1 -Wno-unused-parameter -Wno-empty-body -Wno-missing-field-initializers -Wno-attributes -Wno-sign-compare -Wno-pointer-sign -Werror
-
-# Turn off warnings for now until this is fixed upstream. b/18632512
-LOCAL_CFLAGS += -Wno-unused-variable
-
-LOCAL_MODULE:= pppd
-
-include $(BUILD_EXECUTABLE)
diff --git a/pppd/README.pppol2tp b/pppd/README.pppol2tp
new file mode 100644
index 0000000..e82548a
--- /dev/null
+++ b/pppd/README.pppol2tp
@@ -0,0 +1,33 @@
+PPPoL2TP-Android plugin
+=======================
+
+This PPPoL2TP-Android plugin was written for AOSP project from scratch. It has
+nothing to do with pppol2tp plugin from upstream ppp project [1].
+
+This plugin adds support for upstream kernel L2TP implementation in pppd
+daemon. Only LAC part of L2TP is implemented, as we don't use Android devices
+in LNS mode.
+
+In general case, the execution flow for VPN startup on Android devices is:
+ 1. Run IPSec client (racoon)
+ 2. Run L2TP client (mtpd)
+ 3. mtpd obtains "remote tunnel ID" and "remote session ID" from L2TP server
+ 4. mtpd creates L2TP sockets (see [2] for details):
+    - tunnel management PPPoX socket
+    - session PPPoX data socket
+ 5. mtpd runs pppd, passing arguments for pppol2tp-android plugin
+ 6. pppd dlopen() pppol2tp-android plugin (because it receives corresponding\
+    arguments from mtpd)
+
+Main task of this plugin is to obtain session_fd socket from mtpd and pass it
+back to pppd when .connect() callback is executed. In this respect it's similar
+to old pppox.c implementation. The differences are next:
+ 1. pppol2tp-android also obtains the second socket (for tunnel management)
+    which allows us to handle it properly
+ 2. pppol2tp-android handles the setting of MTU/MRU size (which can be passed
+    to the plugin with pppd parameters) via kernel L2TP implementation
+ 3. pppol2tp-android plugin is actually loaded dynamically with dlopen(),
+    as opposed to pppox.c which is hard-coded into pppd code
+
+[1] https://github.com/paulusmack/ppp
+[2] https://www.kernel.org/doc/Documentation/networking/l2tp.txt
diff --git a/pppd/include/net/ppp_defs.h b/pppd/include/net/ppp_defs.h
index a21afdb..9522290 100644
--- a/pppd/include/net/ppp_defs.h
+++ b/pppd/include/net/ppp_defs.h
@@ -38,6 +38,10 @@
 #ifndef _PPP_DEFS_H_
 #define _PPP_DEFS_H_
 
+#if defined(__linux__)
+#include <linux/ppp_defs.h>
+#endif
+
 #if defined(PPP_ADDRESS)
 #define USING_UAPI
 #endif
@@ -131,6 +135,10 @@ typedef u_int32_t	ext_accm[8];
  * What to do with network protocol (NP) packets.
  */
 #if defined(USING_UAPI)
+
+/* For struct ifreq */
+#include <net/if.h>
+
 /* This stuff isn't in uapi. TODO: is there a newer pppd that doesn't use this? */
 #define ifr__name b.ifr_ifrn.ifrn_name
 #define stats_ptr b.ifr_ifru.ifru_data
diff --git a/pppd/main.c b/pppd/main.c
index 5424e42..09f5a53 100644
--- a/pppd/main.c
+++ b/pppd/main.c
@@ -357,39 +357,16 @@ main(argc, argv)
      */
     tty_init();
 
-    progname = *argv;
-
 #if defined(__ANDROID__)
     {
         extern void pppox_init();
         pppox_init();
         privileged = 1;
     }
-    {
-        char *envargs = getenv("envargs");
-        if (envargs) {
-            int i;
-            /* Decode the arguments in-place and count the number of them.
-             * They were hex encoded using [A-P] instead of [0-9A-F]. */
-            for (argc = 0, i = 0; envargs[i] && envargs[i + 1]; i += 2) {
-                char c = ((envargs[i] - 'A') << 4) + (envargs[i + 1] - 'A');
-                if (c == 0) {
-                    ++argc;
-                }
-                envargs[i / 2 + 1] = c;
-            }
-            if (argc == 0 || (argv = malloc(sizeof(char *) * argc)) == NULL) {
-                fatal("Failed to parse envargs!");
-            }
-            for (envargs[0] = 0, i = 0; i < argc; ++envargs) {
-                if (envargs[0] == 0) {
-                    argv[i++] = &envargs[1];
-                }
-            }
-        }
-    }
 #endif
 
+    progname = *argv;
+
     /*
      * Parse, in order, the system options file, the user's options file,
      * and the command line arguments.
diff --git a/pppd/pathnames.h b/pppd/pathnames.h
index a33f046..ea74736 100644
--- a/pppd/pathnames.h
+++ b/pppd/pathnames.h
@@ -56,10 +56,26 @@
 #endif /* __STDC__ */
 
 #ifdef PLUGIN
+#ifdef __ANDROID__
+
+/*
+ * In Android we can't load plugins from /system/lib{64}/pppd/, because
+ * Bionic loader only allows us to dlopen() libraries from /system/lib{64} root
+ * directory (as specified in ld.config.txt, see "default" linker namespace).
+ */
+#ifdef __LP64__
+#define _PATH_PLUGIN	"/system/lib64"
+#else  /* __LP64__ */
+#define _PATH_PLUGIN	"/system/lib"
+#endif /* __LP64__ */
+
+#else /* __ANDROID__ */
+
 #ifdef __STDC__
 #define _PATH_PLUGIN	DESTDIR "/lib/pppd/" VERSION
 #else /* __STDC__ */
 #define _PATH_PLUGIN	"/usr/lib/pppd"
 #endif /* __STDC__ */
 
+#endif /* __ANDROID__ */
 #endif /* PLUGIN */
diff --git a/pppd/plugins/pppol2tp-android/pppol2tp-android.c b/pppd/plugins/pppol2tp-android/pppol2tp-android.c
new file mode 100644
index 0000000..6a984de
--- /dev/null
+++ b/pppd/plugins/pppol2tp-android/pppol2tp-android.c
@@ -0,0 +1,129 @@
+/*
+ * Copyright (C) 2018 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.
+ */
+
+#include "pppd.h"
+#include "fsm.h"
+#include "lcp.h"
+#include <unistd.h>
+#include <sys/ioctl.h>
+#include <linux/if_ppp.h>
+
+char pppd_version[] = VERSION;
+
+static struct channel pppol2tp_channel;
+
+/* Options variables */
+static int session_fd = -1;
+static int tunnel_fd = -1;
+static int session_id = 0;
+static int tunnel_id = 0;
+
+static int pppol2tp_set_session_fd(char **argv);
+
+static option_t pppol2tp_options[] = {
+	{ "session_fd", o_special, pppol2tp_set_session_fd,
+		"Session PPPoX data socket", OPT_DEVNAM },
+	{ "tunnel_fd", o_int, &tunnel_fd,
+		"Tunnel management PPPoX socket", OPT_PRIO },
+	{ "session_id", o_int, &session_id, "Session ID", OPT_PRIO },
+	{ "tunnel_id", o_int, &tunnel_id, "Tunnel ID", OPT_PRIO },
+	{ NULL }
+};
+
+static int pppol2tp_set_session_fd(char **argv)
+{
+	if (!int_option(*argv, &session_fd))
+		return 0;
+
+	info("Using PPPoL2TP (socket = %d)", session_fd);
+	the_channel = &pppol2tp_channel;
+	return 1;
+}
+
+/**
+ * Set the MRU on the PPP network interface.
+ *
+ * @param mru New MRU value
+ *
+ * @note netif_set_mru() is missing in sys-linux.c, so implement it manually
+ * @note See net/l2tp/l2tp_ppp.c:pppol2tp_session_ioctl() in kernel for details
+ */
+static void pppol2tp_set_mru(int mru)
+{
+	int res;
+
+	if (ifunit < 0)
+		return;
+
+	res = ioctl(session_fd, PPPIOCSMRU, (caddr_t)&mru);
+	if (res < 0)
+		error("ioctl(PPPIOCSMRU): %m (line %d)", __LINE__);
+}
+
+/* Set the transmit-side PPP parameters of the channel */
+static void pppol2tp_send_config(int mtu, u_int32_t accm, int pcomp, int accomp)
+{
+	int new_mtu = lcp_allowoptions[0].mru;	/* "mtu" pppd option */
+
+	if (new_mtu <= PPP_MAXMTU && new_mtu >= PPP_MINMTU)
+		netif_set_mtu(ifunit, new_mtu);
+}
+
+/* Set the receive-side PPP parameters of the channel */
+static void pppol2tp_recv_config(int mru, u_int32_t accm, int pcomp, int accomp)
+{
+	int new_mru = lcp_wantoptions[0].mru;	/* "mru" pppd option */
+
+	if (new_mru <= PPP_MAXMRU && new_mru >= PPP_MINMRU)
+		pppol2tp_set_mru(new_mru);
+}
+
+static int pppol2tp_connect(void)
+{
+	return session_fd;
+}
+
+static void pppol2tp_disconnect(void)
+{
+	if (session_fd != -1) {
+		close(session_fd);
+		session_fd = -1;
+	}
+
+	if (tunnel_fd != -1) {
+		close(tunnel_fd);
+		tunnel_fd = -1;
+	}
+}
+
+void plugin_init(void)
+{
+	add_options(pppol2tp_options);
+}
+
+static struct channel pppol2tp_channel = {
+	.options		= pppol2tp_options,
+	.process_extra_options	= NULL,
+	.check_options		= NULL,
+	.connect		= pppol2tp_connect,
+	.disconnect		= pppol2tp_disconnect,
+	.establish_ppp		= generic_establish_ppp,
+	.disestablish_ppp	= generic_disestablish_ppp,
+	.send_config		= pppol2tp_send_config,
+	.recv_config		= pppol2tp_recv_config,
+	.cleanup		= NULL,
+	.close			= NULL,
+};