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      1 /*
      2  * Copyright (C) 2011 The Android Open Source Project
      3  *
      4  * Licensed under the Apache License, Version 2.0 (the "License");
      5  * you may not use this file except in compliance with the License.
      6  * You may obtain a copy of the License at
      7  *
      8  *      http://www.apache.org/licenses/LICENSE-2.0
      9  *
     10  * Unless required by applicable law or agreed to in writing, software
     11  * distributed under the License is distributed on an "AS IS" BASIS,
     12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     13  * See the License for the specific language governing permissions and
     14  * limitations under the License.
     15  */
     16 
     17 #define LOG_TAG "ip-up-vpn"
     18 
     19 #include <arpa/inet.h>
     20 #include <errno.h>
     21 #include <linux/if.h>
     22 #include <linux/route.h>
     23 #include <netinet/in.h>
     24 #include <stdio.h>
     25 #include <stdlib.h>
     26 #include <string.h>
     27 #include <sys/ioctl.h>
     28 #include <sys/socket.h>
     29 #include <sys/stat.h>
     30 #include <sys/types.h>
     31 
     32 #include <log/log.h>
     33 
     34 #define DIR "/data/misc/vpn/"
     35 
     36 static const char *env(const char *name) {
     37     const char *value = getenv(name);
     38     return value ? value : "";
     39 }
     40 
     41 static int set_address(struct sockaddr *sa, const char *address) {
     42     sa->sa_family = AF_INET;
     43     errno = EINVAL;
     44     return inet_pton(AF_INET, address, &((struct sockaddr_in *)sa)->sin_addr);
     45 }
     46 
     47 /*
     48  * The primary goal is to create a file with VPN parameters. Currently they
     49  * are interface, addresses, routes, DNS servers, and search domains and VPN
     50  * server address. Each parameter occupies one line in the file, and it can be
     51  * an empty string or space-separated values. The order and the format must be
     52  * consistent with com.android.server.connectivity.Vpn. Here is an example.
     53  *
     54  *   ppp0
     55  *   192.168.1.100/24
     56  *   0.0.0.0/0
     57  *   192.168.1.1 192.168.1.2
     58  *   example.org
     59  *   192.0.2.1
     60  *
     61  * The secondary goal is to unify the outcome of VPN. The current baseline
     62  * is to have an interface configured with the given address and netmask
     63  * and maybe add a host route to protect the tunnel. PPP-based VPN already
     64  * does this, but others might not. Routes, DNS servers, and search domains
     65  * are handled by the framework since they can be overridden by the users.
     66  */
     67 int main(int argc, char **argv)
     68 {
     69     FILE *state = fopen(DIR ".tmp", "wb");
     70     if (!state) {
     71         ALOGE("Cannot create state: %s", strerror(errno));
     72         return 1;
     73     }
     74 
     75     if (argc >= 6) {
     76         /* Invoked by pppd. */
     77         fprintf(state, "%s\n", argv[1]);
     78         fprintf(state, "%s/32\n", argv[4]);
     79         fprintf(state, "0.0.0.0/0\n");
     80         fprintf(state, "%s %s\n", env("DNS1"), env("DNS2"));
     81         fprintf(state, "\n");
     82         fprintf(state, "\n");
     83     } else if (argc == 2) {
     84         /* Invoked by racoon. */
     85         const char *interface = env("INTERFACE");
     86         const char *address = env("INTERNAL_ADDR4");
     87         const char *routes = env("SPLIT_INCLUDE_CIDR");
     88 
     89         int s = socket(AF_INET, SOCK_DGRAM, 0);
     90         struct ifreq ifr;
     91         memset(&ifr, 0, sizeof(ifr));
     92 
     93         /* Bring up the interface. */
     94         ifr.ifr_flags = IFF_UP;
     95         strncpy(ifr.ifr_name, interface, IFNAMSIZ);
     96         if (ioctl(s, SIOCSIFFLAGS, &ifr)) {
     97             ALOGE("Cannot bring up %s: %s", interface, strerror(errno));
     98             return 1;
     99         }
    100 
    101         /* Set the address. */
    102         if (!set_address(&ifr.ifr_addr, address) ||
    103                 ioctl(s, SIOCSIFADDR, &ifr)) {
    104             ALOGE("Cannot set address: %s", strerror(errno));
    105             return 1;
    106         }
    107 
    108         /* Set the netmask. */
    109         if (set_address(&ifr.ifr_netmask, env("INTERNAL_NETMASK4"))) {
    110             if (ioctl(s, SIOCSIFNETMASK, &ifr)) {
    111                 ALOGE("Cannot set netmask: %s", strerror(errno));
    112                 return 1;
    113             }
    114         }
    115 
    116         /* TODO: Send few packets to trigger phase 2? */
    117 
    118         fprintf(state, "%s\n", interface);
    119         fprintf(state, "%s/%s\n", address, env("INTERNAL_CIDR4"));
    120         fprintf(state, "%s\n", routes[0] ? routes : "0.0.0.0/0");
    121         fprintf(state, "%s\n", env("INTERNAL_DNS4_LIST"));
    122         fprintf(state, "%s\n", env("DEFAULT_DOMAIN"));
    123         fprintf(state, "%s\n", env("REMOTE_ADDR"));
    124     } else {
    125         ALOGE("Cannot parse parameters");
    126         return 1;
    127     }
    128 
    129     fclose(state);
    130     if (chmod(DIR ".tmp", 0444) || rename(DIR ".tmp", DIR "state")) {
    131         ALOGE("Cannot write state: %s", strerror(errno));
    132         return 1;
    133     }
    134     return 0;
    135 }
    136