BadVPN – Rev 1
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/**
* @file net_backend_badvpn.c
* @author Ambroz Bizjak <ambrop7@gmail.com>
*
* @section LICENSE
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. Neither the name of the author nor the
* names of its contributors may be used to endorse or promote products
* derived from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
* DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
* ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*
* @section DESCRIPTION
*
* BadVPN interface module.
*
* Synopsis: net.backend.badvpn(string ifname, string user, string exec, list(string) args)
*/
#include <stdlib.h>
#include <string.h>
#include <misc/cmdline.h>
#include <ncd/extra/NCDIfConfig.h>
#include <ncd/module_common.h>
#include <generated/blog_channel_ncd_net_backend_badvpn.h>
#define RETRY_TIME 5000
struct instance {
NCDModuleInst *i;
NCDValNullTermString ifname_nts;
NCDValNullTermString user_nts;
MemRef exec;
NCDValRef args;
int dying;
int started;
BTimer timer;
BProcess process;
};
static void try_process (struct instance *o);
static void process_handler (struct instance *o, int normally, uint8_t normally_exit_status);
static void timer_handler (struct instance *o);
static void instance_free (struct instance *o);
void try_process (struct instance *o)
{
CmdLine c;
if (!CmdLine_Init(&c)) {
goto fail0;
}
// append exec
if (!CmdLine_AppendNoNullMr(&c, o->exec)) {
goto fail1;
}
// append tapdev
if (!CmdLine_Append(&c, "--tapdev") || !CmdLine_Append(&c, o->ifname_nts.data)) {
goto fail1;
}
// append arguments
size_t count = NCDVal_ListCount(o->args);
for (size_t j = 0; j < count; j++) {
NCDValRef arg = NCDVal_ListGet(o->args, j);
if (!CmdLine_AppendNoNullMr(&c, NCDVal_StringMemRef(arg))) {
goto fail1;
}
}
// terminate cmdline
if (!CmdLine_Finish(&c)) {
goto fail1;
}
// start process
if (!BProcess_Init(&o->process, o->i->params->iparams->manager, (BProcess_handler)process_handler, o, ((char **)c.arr.v)[0], (char **)c.arr.v, o->user_nts.data)) {
ModuleLog(o->i, BLOG_ERROR, "BProcess_Init failed");
goto fail1;
}
CmdLine_Free(&c);
// set started
o->started = 1;
return;
fail1:
CmdLine_Free(&c);
fail0:
// retry
o->started = 0;
BReactor_SetTimer(o->i->params->iparams->reactor, &o->timer);
}
void process_handler (struct instance *o, int normally, uint8_t normally_exit_status)
{
ASSERT(o->started)
ModuleLog(o->i, BLOG_INFO, "process terminated");
// free process
BProcess_Free(&o->process);
// set not started
o->started = 0;
if (o->dying) {
instance_free(o);
return;
}
// set timer
BReactor_SetTimer(o->i->params->iparams->reactor, &o->timer);
}
void timer_handler (struct instance *o)
{
ASSERT(!o->started)
ModuleLog(o->i, BLOG_INFO, "retrying");
// try starting process again
try_process(o);
}
static void func_new (void *vo, NCDModuleInst *i, const struct NCDModuleInst_new_params *params)
{
struct instance *o = vo;
o->i = i;
// read arguments
NCDValRef ifname_arg;
NCDValRef user_arg;
NCDValRef exec_arg;
NCDValRef args_arg;
if (!NCDVal_ListRead(params->args, 4, &ifname_arg, &user_arg, &exec_arg, &args_arg)) {
ModuleLog(o->i, BLOG_ERROR, "wrong arity");
goto fail0;
}
if (!NCDVal_IsStringNoNulls(ifname_arg) || !NCDVal_IsStringNoNulls(user_arg) ||
!NCDVal_IsStringNoNulls(exec_arg) || !NCDVal_IsList(args_arg)) {
ModuleLog(o->i, BLOG_ERROR, "wrong type");
goto fail0;
}
o->exec = NCDVal_StringMemRef(exec_arg);
o->args = args_arg;
// check arguments
size_t count = NCDVal_ListCount(o->args);
for (size_t j = 0; j < count; j++) {
NCDValRef arg = NCDVal_ListGet(o->args, j);
if (!NCDVal_IsStringNoNulls(arg)) {
ModuleLog(o->i, BLOG_ERROR, "wrong type");
goto fail0;
}
}
// null terminate user
if (!NCDVal_StringNullTerminate(user_arg, &o->user_nts)) {
ModuleLog(i, BLOG_ERROR, "NCDVal_StringNullTerminate failed");
goto fail0;
}
// null terminate ifname
if (!NCDVal_StringNullTerminate(ifname_arg, &o->ifname_nts)) {
ModuleLog(i, BLOG_ERROR, "NCDVal_StringNullTerminate failed");
goto fail1;
}
// create TAP device
if (!NCDIfConfig_make_tuntap(o->ifname_nts.data, o->user_nts.data, 0)) {
ModuleLog(o->i, BLOG_ERROR, "failed to create TAP device");
goto fail2;
}
// set device up
if (!NCDIfConfig_set_up(o->ifname_nts.data)) {
ModuleLog(o->i, BLOG_ERROR, "failed to set device up");
goto fail3;
}
// set not dying
o->dying = 0;
// init timer
BTimer_Init(&o->timer, RETRY_TIME, (BTimer_handler)timer_handler, o);
// signal up
NCDModuleInst_Backend_Up(o->i);
// try starting process
try_process(o);
return;
fail3:
if (!NCDIfConfig_remove_tuntap(o->ifname_nts.data, 0)) {
ModuleLog(o->i, BLOG_ERROR, "failed to remove TAP device");
}
fail2:
NCDValNullTermString_Free(&o->ifname_nts);
fail1:
NCDValNullTermString_Free(&o->user_nts);
fail0:
NCDModuleInst_Backend_DeadError(i);
}
void instance_free (struct instance *o)
{
ASSERT(!o->started)
// free timer
BReactor_RemoveTimer(o->i->params->iparams->reactor, &o->timer);
// set device down
if (!NCDIfConfig_set_down(o->ifname_nts.data)) {
ModuleLog(o->i, BLOG_ERROR, "failed to set device down");
}
// free TAP device
if (!NCDIfConfig_remove_tuntap(o->ifname_nts.data, 0)) {
ModuleLog(o->i, BLOG_ERROR, "failed to remove TAP device");
}
// free ifname nts
NCDValNullTermString_Free(&o->ifname_nts);
// free user nts
NCDValNullTermString_Free(&o->user_nts);
NCDModuleInst_Backend_Dead(o->i);
}
static void func_die (void *vo)
{
struct instance *o = vo;
ASSERT(!o->dying)
if (!o->started) {
instance_free(o);
return;
}
// request termination
BProcess_Terminate(&o->process);
// remember dying
o->dying = 1;
}
static struct NCDModule modules[] = {
{
.type = "net.backend.badvpn",
.func_new2 = func_new,
.func_die = func_die,
.alloc_size = sizeof(struct instance)
}, {
.type = NULL
}
};
const struct NCDModuleGroup ncdmodule_net_backend_badvpn = {
.modules = modules
};