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#include <stdio.h>
18#include <stdlib.h>
19#include <string.h>
20#include <errno.h>
21
22#include <arpa/inet.h>
23#include <netinet/in.h>
24#include <sys/stat.h>
25#include <sys/types.h>
26#include <sys/socket.h>
27#include <sys/ioctl.h>
28#include <linux/if.h>
29#include <linux/route.h>
30
31#define LOG_TAG "ip-up-vpn"
32#include <cutils/log.h>
33
34#define DIR "/data/misc/vpn/"
35
36static const char *env(const char *name) {
37    const char *value = getenv(name);
38    return value ? value : "";
39}
40
41static 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. Each
50 * parameter occupies one line in the file, and it can be an empty string or
51 * space-separated values. The order and the format must be consistent with
52 * 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 *
60 * The secondary goal is to unify the outcome of VPN. The current baseline
61 * is to have an interface configured with the given address and netmask
62 * and maybe add a host route to protect the tunnel. PPP-based VPN already
63 * does this, but others might not. Routes, DNS servers, and search domains
64 * are handled by the framework since they can be overridden by the users.
65 */
66int main(int argc, char **argv)
67{
68    FILE *state = fopen(DIR ".tmp", "wb");
69    if (!state) {
70        ALOGE("Cannot create state: %s", strerror(errno));
71        return 1;
72    }
73
74    if (argc >= 6) {
75        /* Invoked by pppd. */
76        fprintf(state, "%s\n", argv[1]);
77        fprintf(state, "%s/32\n", argv[4]);
78        fprintf(state, "0.0.0.0/0\n");
79        fprintf(state, "%s %s\n", env("DNS1"), env("DNS2"));
80        fprintf(state, "\n");
81    } else if (argc == 2) {
82        /* Invoked by racoon. */
83        const char *interface = env("INTERFACE");
84        const char *address = env("INTERNAL_ADDR4");
85        const char *routes = env("SPLIT_INCLUDE_CIDR");
86
87        int s = socket(AF_INET, SOCK_DGRAM, 0);
88        struct rtentry rt;
89        struct ifreq ifr;
90
91        memset(&rt, 0, sizeof(rt));
92        memset(&ifr, 0, sizeof(ifr));
93
94        /* Remove the old host route. There could be more than one. */
95        rt.rt_flags |= RTF_UP | RTF_HOST;
96        if (set_address(&rt.rt_dst, env("REMOTE_ADDR"))) {
97            while (!ioctl(s, SIOCDELRT, &rt));
98        }
99        if (errno != ESRCH) {
100            ALOGE("Cannot remove host route: %s", strerror(errno));
101            return 1;
102        }
103
104        /* Create a new host route. */
105        rt.rt_flags |= RTF_GATEWAY;
106        if (!set_address(&rt.rt_gateway, argv[1]) ||
107                (ioctl(s, SIOCADDRT, &rt) && errno != EEXIST)) {
108            ALOGE("Cannot create host route: %s", strerror(errno));
109            return 1;
110        }
111
112        /* Bring up the interface. */
113        ifr.ifr_flags = IFF_UP;
114        strncpy(ifr.ifr_name, interface, IFNAMSIZ);
115        if (ioctl(s, SIOCSIFFLAGS, &ifr)) {
116            ALOGE("Cannot bring up %s: %s", interface, strerror(errno));
117            return 1;
118        }
119
120        /* Set the address. */
121        if (!set_address(&ifr.ifr_addr, address) ||
122                ioctl(s, SIOCSIFADDR, &ifr)) {
123            ALOGE("Cannot set address: %s", strerror(errno));
124            return 1;
125        }
126
127        /* Set the netmask. */
128        if (set_address(&ifr.ifr_netmask, env("INTERNAL_NETMASK4"))) {
129            if (ioctl(s, SIOCSIFNETMASK, &ifr)) {
130                ALOGE("Cannot set netmask: %s", strerror(errno));
131                return 1;
132            }
133        }
134
135        /* TODO: Send few packets to trigger phase 2? */
136
137        fprintf(state, "%s\n", interface);
138        fprintf(state, "%s/%s\n", address, env("INTERNAL_CIDR4"));
139        fprintf(state, "%s\n", routes[0] ? routes : "0.0.0.0/0");
140        fprintf(state, "%s\n", env("INTERNAL_DNS4_LIST"));
141        fprintf(state, "%s\n", env("DEFAULT_DOMAIN"));
142    } else {
143        ALOGE("Cannot parse parameters");
144        return 1;
145    }
146
147    fclose(state);
148    if (chmod(DIR ".tmp", 0444) || rename(DIR ".tmp", DIR "state")) {
149        ALOGE("Cannot write state: %s", strerror(errno));
150        return 1;
151    }
152    return 0;
153}
154