pppd: Implement ip-up-vpn to modify routing table when vpn is up.

diff --git a/android/Android.mk b/android/Android.mk
new file mode 100644 (file)
index 0000000..25c4c58
--- /dev/null
+++ b/android/Android.mk
@@ -0,0 +1,25 @@
+#
+# 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.
+#
+
+LOCAL_PATH := $(call my-dir)
+include $(CLEAR_VARS)
+
+LOCAL_SRC_FILES := ip-up-vpn.c
+LOCAL_SHARED_LIBRARIES := libcutils
+LOCAL_MODULE := ip-up-vpn
+LOCAL_MODULE_PATH := $(TARGET_OUT_ETC)/ppp
+
+include $(BUILD_EXECUTABLE)

diff --git a/android/ip-up-vpn.c b/android/ip-up-vpn.c
new file mode 100644 (file)
index 0000000..afc85f4
--- /dev/null
+++ b/android/ip-up-vpn.c
@@ -0,0 +1,89 @@
+/*
+ * 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.
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <errno.h>
+#include <sys/ioctl.h>
+#include <sys/types.h>
+#include <sys/socket.h>
+#include <netinet/in.h>
+#include <arpa/inet.h>
+#include <linux/route.h>
+
+#include <android/log.h>
+#include <cutils/properties.h>
+
+static inline struct in_addr *in_addr(struct sockaddr *sa)
+{
+    return &((struct sockaddr_in *)sa)->sin_addr;
+}
+
+int main(int argc, char **argv)
+{
+    struct rtentry route = {
+        .rt_dst     = {.sa_family = AF_INET},
+        .rt_genmask = {.sa_family = AF_INET},
+        .rt_gateway = {.sa_family = AF_INET},
+        .rt_flags   = RTF_UP | RTF_GATEWAY,
+    };
+    FILE *f;
+    int s;
+
+    errno = EINVAL;
+    if (argc > 5 && inet_aton(argv[5], in_addr(&route.rt_gateway)) &&
+        (f = fopen("/proc/net/route", "r")) != NULL &&
+        (s = socket(AF_INET, SOCK_DGRAM, 0)) != -1) {
+        uint32_t *address = &in_addr(&route.rt_dst)->s_addr;
+        uint32_t *netmask = &in_addr(&route.rt_genmask)->s_addr;
+        char device[64];
+
+        fscanf(f, "%*[^\n]\n");
+        while (fscanf(f, "%63s%X%*X%*X%*d%*u%*d%X%*d%*u%*u\n",
+                      device, address, netmask) == 3) {
+            if (strcmp(argv[1], device)) {
+                uint32_t bit = ntohl(*netmask);
+                bit = htonl(bit ^ (1 << 31 | bit >> 1));
+                if (bit) {
+                    *netmask |= bit;
+                    if (ioctl(s, SIOCADDRT, &route) == -1 && errno != EEXIST) {
+                        break;
+                    }
+                    *address ^= bit;
+                    if (ioctl(s, SIOCADDRT, &route) == -1 && errno != EEXIST) {
+                        break;
+                    }
+                    errno = 0;
+                }
+            }
+        }
+    }
+
+    if (!errno) {
+        char *dns = getenv("DNS1");
+        property_set("vpn.dns1", dns ? dns : "");
+        dns = getenv("DNS2");
+        property_set("vpn.dns2", dns ? dns : "");
+        property_set("vpn.status", "ok");
+        __android_log_print(ANDROID_LOG_INFO, "ip-up-vpn",
+                            "All traffic is now redirected to %s", argv[5]);
+    } else {
+        property_set("vpn.status", "error");
+        __android_log_write(ANDROID_LOG_ERROR, "ip-up-vpn", strerror(errno));
+    }
+    return errno;
+}