mirror of
https://github.com/servalproject/serval-dna.git
synced 2024-12-21 06:03:12 +00:00
318 lines
10 KiB
C
318 lines
10 KiB
C
/*
|
|
Serval Distributed Numbering Architecture (DNA)
|
|
Copyright (C) 2010 Paul Gardner-Stephen
|
|
|
|
This program is free software; you can redistribute it and/or
|
|
modify it under the terms of the GNU General Public License
|
|
as published by the Free Software Foundation; either version 2
|
|
of the License, or (at your option) any later version.
|
|
|
|
This program is distributed in the hope that it will be useful,
|
|
but WITHOUT ANY WARRANTY; without even the implied warranty of
|
|
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
|
|
GNU General Public License for more details.
|
|
|
|
You should have received a copy of the GNU General Public License
|
|
along with this program; if not, write to the Free Software
|
|
Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
|
|
*/
|
|
|
|
#include <time.h>
|
|
#include <sys/stat.h>
|
|
#include <sys/wait.h>
|
|
#include "serval.h"
|
|
|
|
char *asterisk_extensions_conf="/data/data/org.servalproject/asterisk/etc/asterisk/gatewayextensions.conf";
|
|
char *asterisk_binary="/data/data/org.servalproject/asterisk/sbin/asterisk";
|
|
char *temp_file="/data/data/org.servalproject/var/temp.out";
|
|
char *cmd_file="/data/data/org.servalproject/var/temp.cmd";
|
|
char *shell="/system/bin/sh";
|
|
char *gatewayspec=NULL;
|
|
|
|
typedef struct dna_gateway_extension {
|
|
char did[64];
|
|
char requestor_sid[SID_SIZE+1];
|
|
char uri[256-64-SID_SIZE-1-sizeof(int)-(sizeof(time_t)*2)];
|
|
int uriprefixlen;
|
|
time_t created; /* 0 == free */
|
|
time_t expires; /* 0 == free */
|
|
} dna_gateway_extension;
|
|
|
|
#define MAX_CURRENT_EXTENSIONS 1024
|
|
dna_gateway_extension extensions[MAX_CURRENT_EXTENSIONS];
|
|
|
|
int prepareGateway(char *spec)
|
|
{
|
|
if ((!strcasecmp(spec,"potato"))||(!strcasecmp(spec,"meshpotato"))||(!strcasecmp(spec,"mp"))||(!strcasecmp(spec,"mp1"))) {
|
|
/* Setup for mesh potato */
|
|
asterisk_extensions_conf="/etc/asterisk/gatewayextensions.conf";
|
|
asterisk_binary="/usr/sbin/asterisk";
|
|
temp_file="/var/dnatemp.out";
|
|
cmd_file="/var/dnatemp.cmd";
|
|
shell="/bin/sh";
|
|
return 0;
|
|
} else if ((!strcasecmp(spec,"android"))||(!strcasecmp(spec,"batphone"))) {
|
|
/* Setup for android -- this is default, so don't change anything */
|
|
return 0;
|
|
} else if (!strncasecmp(spec,"custom:",7)) {
|
|
char a[1024],b[1024],c[1024],d[1024],e[1024];
|
|
if (sscanf(spec,"custom:%[^:]:%[^:]:%[^:]:%[^:]:%[^:]",a,b,c,d,e)!=5) return WHY("Invalid custom gateway specification");
|
|
asterisk_extensions_conf=strdup(a);
|
|
asterisk_binary=strdup(b);
|
|
temp_file=strdup(c);
|
|
cmd_file=strdup(d);
|
|
shell=strdup(e);
|
|
return 0;
|
|
}
|
|
else
|
|
return WHY("Invalid gateway specification");
|
|
}
|
|
|
|
int safeSystem(char *cmd_file)
|
|
{
|
|
{
|
|
int pid = fork();
|
|
|
|
if(pid == -1) {
|
|
fprintf(stderr, "Unable to fork.\n");
|
|
return -1;
|
|
} else if(pid == 0) {
|
|
execlp(shell, shell, "-c", cmd_file,NULL);
|
|
exit(1);
|
|
} else {
|
|
// Wait for child to finish
|
|
int status;
|
|
wait(&status);
|
|
return WEXITSTATUS(status);
|
|
}
|
|
}
|
|
}
|
|
|
|
int runCommand(char *cmd)
|
|
{
|
|
FILE *f=fopen(cmd_file,"w");
|
|
if (!f) {
|
|
if (debug&DEBUG_GATEWAY) fprintf(stderr,"%s:%d: Could not write to command file '%s'.\n",__FUNCTION__,__LINE__,cmd_file);
|
|
return 0;
|
|
}
|
|
fprintf(f,"#!%s\n%s\n",shell,cmd);
|
|
fclose(f);
|
|
if (chmod(cmd_file,0000700))
|
|
{
|
|
if (debug&DEBUG_GATEWAY) fprintf(stderr,"%s:%d: Could not chmod command file '%s'.\n",__FUNCTION__,__LINE__,cmd_file);
|
|
return 0;
|
|
}
|
|
return safeSystem(cmd_file);
|
|
}
|
|
|
|
int gatewayReadSettings(char *file)
|
|
{
|
|
char line[1024];
|
|
FILE *f=fopen(file,"r");
|
|
if (!f) return -1;
|
|
|
|
/* Location of extensions.conf file to write
|
|
(really it would be a file you #include from extensions.conf) */
|
|
line[0]=0; fgets(line,1024,f);
|
|
asterisk_extensions_conf=strdup(line);
|
|
|
|
/* The command required to get Asterisk to re-read the above file */
|
|
line[0]=0; fgets(line,1024,f);
|
|
asterisk_binary=strdup(line);
|
|
|
|
/* Temporary file for catching Asterisk output from -rx commands */
|
|
line[0]=0; fgets(line,1024,f);
|
|
temp_file=strdup(line);
|
|
|
|
/* Temporary file for running asterisk commands (since system() cannot do redirection on android) */
|
|
line[0]=0; fgets(line,1024,f);
|
|
cmd_file=strdup(line);
|
|
|
|
line[0]=0; fgets(line,1024,f);
|
|
shell=strdup(line);
|
|
|
|
/* XXX Need more here I suspect */
|
|
|
|
fclose(f);
|
|
return 0;
|
|
}
|
|
|
|
int asteriskCreateExtension(char *requestor_sid,char *did,char *uri_out)
|
|
{
|
|
/* XXX There are denial of service attacks that we have to consider here.
|
|
Primarily, naughty persons could flood the gateway with false solicitations filling the
|
|
current extension table and slowing asterisk down with lots of reloads.
|
|
|
|
Our mitigation strategy is to use a random replacement scheme, except where the same SID
|
|
has an entry in the table already, in which case we should replace that one.
|
|
Replacement entails a search, which should be done using a tree structure for speed.
|
|
Since right now we just want to get the functionality working, we will just do random replacement
|
|
no matter what.
|
|
*/
|
|
|
|
/* XXX We should add authentication checks and number validity checks here, e.g., if a gateway only wants to
|
|
allow access for a certain group of users, and/or to only a certain range of numbers */
|
|
|
|
/* XXX The "secret" extension is only secret if we encrypt the reply packet! */
|
|
|
|
int index=random()%MAX_CURRENT_EXTENSIONS;
|
|
|
|
bcopy(requestor_sid,extensions[index].requestor_sid,SID_SIZE);
|
|
strcpy(extensions[index].did,did);
|
|
extensions[index].created=time(0);
|
|
extensions[index].expires=time(0)+3600;
|
|
snprintf(extensions[index].uri,sizeof(extensions[index].uri),"4101*%08x%04x@",
|
|
(unsigned int)random(),(unsigned int)random()&0xffff);
|
|
extensions[index].uriprefixlen=strlen(extensions[index].uri)-1;
|
|
if (extensions[index].uriprefixlen<0) {
|
|
/* Whoops - something wrong with the extension/uri, so kill the record and fail. */
|
|
extensions[index].expires=1;
|
|
if (debug&DEBUG_GATEWAY) fprintf(stderr,"%s:%d: Generated extension appears to be malformed.\n",__FUNCTION__,__LINE__);
|
|
return -1;
|
|
}
|
|
|
|
if (debug&DEBUG_GATEWAY) fprintf(stderr,"Created extension '%s' to dial %s\n",extensions[index].uri,did);
|
|
strcpy(uri_out,extensions[index].uri);
|
|
|
|
return 0;
|
|
}
|
|
|
|
int asteriskWriteExtensions()
|
|
{
|
|
int i;
|
|
time_t now=time(0);
|
|
FILE *out;
|
|
|
|
out=fopen(asterisk_extensions_conf,"w");
|
|
if (!out) {
|
|
if (debug&DEBUG_GATEWAY) fprintf(stderr,"%s:%d: Could not write extensions file '%s'.\n",__FUNCTION__,__LINE__,asterisk_extensions_conf);
|
|
return -1;
|
|
}
|
|
|
|
for(i=0;i<MAX_CURRENT_EXTENSIONS;i++)
|
|
{
|
|
if (extensions[i].expires)
|
|
{
|
|
if (extensions[i].expires<now)
|
|
{
|
|
/* Clear expired gateway extensions */
|
|
bzero(&extensions[i],sizeof(dna_gateway_extension));
|
|
}
|
|
else
|
|
{
|
|
extensions[i].uri[extensions[i].uriprefixlen]=0;
|
|
fprintf(out,
|
|
"exten => %s, 1, Dial(SIP/dnagateway/%s)\n"
|
|
"exten => %s, 2, Hangup()\n",
|
|
extensions[i].uri,
|
|
extensions[i].did,
|
|
extensions[i].uri);
|
|
extensions[i].uri[extensions[i].uriprefixlen]='@';
|
|
}
|
|
}
|
|
}
|
|
fclose(out);
|
|
return 0;
|
|
}
|
|
|
|
int asteriskReloadExtensions()
|
|
{
|
|
char cmd[8192];
|
|
snprintf(cmd,8192,"%s -rx 'dialplan reload'",asterisk_binary);
|
|
if (runCommand(cmd))
|
|
{
|
|
if (debug&DEBUG_GATEWAY) fprintf(stderr,"%s:%d: Dialplan reload failed.\n",__FUNCTION__,__LINE__);
|
|
return -1;
|
|
}
|
|
if (debug&DEBUG_GATEWAY) fprintf(stderr,"%s:%d: Dialplan reload appeared to succeed.\n",__FUNCTION__,__LINE__);
|
|
return 0;
|
|
}
|
|
|
|
int asteriskGatewayUpP()
|
|
{
|
|
int registered=0;
|
|
|
|
/*
|
|
1. Run "serval dna gateway" command to enquire of gateway status?
|
|
No, as that enquires of the wrong DNA instance. Also, we are now controlling the
|
|
enable/disable by checking the outbound SIP gateway status in asterisk, and the
|
|
BatPhone settings screen controls the availability of that by re-writing asterisk config files.
|
|
2. Check that outbound SIP gateway is up:
|
|
asterisk -r "sip show registry"
|
|
and grep output for active links.
|
|
XXX - Annoyingly we need to know the server hostname to use the output of this list in
|
|
a fool-proof manner. However, if we work on the assumption of only one SIP registration existing,
|
|
being ours, then we can ignore the hostname.
|
|
*/
|
|
char cmd[8192];
|
|
|
|
unlink(temp_file);
|
|
snprintf(cmd,8192,"%s -rx 'sip show registry' > %s",asterisk_binary,temp_file);
|
|
|
|
if (runCommand(cmd)) {
|
|
if (debug&DEBUG_GATEWAY) { fprintf(stderr,"%s:%d: system(%s) might have failed.\n",__FUNCTION__,__LINE__,cmd_file);
|
|
perror("system"); }
|
|
}
|
|
FILE *f=fopen(temp_file,"r");
|
|
if (!f) {
|
|
if (debug&DEBUG_GATEWAY) fprintf(stderr,"%s:%d: Could not read result of \"sip show registry\" from '%s'.\n",__FUNCTION__,__LINE__,temp_file);
|
|
return 0;
|
|
}
|
|
|
|
/* Output of command is something like:
|
|
Host Username Refresh State Reg.Time
|
|
houstin.voip.ms:5060 103585 120 Unregistered
|
|
*/
|
|
|
|
cmd[0]=0; fgets(cmd,1024,f);
|
|
while(cmd[0]) {
|
|
char host[1024];
|
|
int port;
|
|
char user[1024];
|
|
int refresh;
|
|
char state[1024];
|
|
|
|
if (sscanf(cmd,"%[^:]:%d%*[ ]%[^ ]%*[ ]%d%*[ ]%[^ ]",
|
|
host,&port,user,&refresh,state)==5)
|
|
{
|
|
// state == "Unregistered" if unavailable, although other values are possible.
|
|
// state == "Registered" if available.
|
|
if (!strcasecmp(state,"Registered")) registered=1; else registered=0;
|
|
}
|
|
cmd[0]=0; fgets(cmd,1024,f);
|
|
}
|
|
|
|
fclose(f);
|
|
|
|
return registered;
|
|
}
|
|
|
|
int asteriskObtainGateway(char *requestor_sid,char *did,char *uri_out)
|
|
{
|
|
/* We use asterisk to provide the gateway service,
|
|
so we need to create a temporary extension in extensions.conf,
|
|
ask asterisk to re-read extensions.conf, and then make sure it has
|
|
a functional SIP gateway.
|
|
*/
|
|
|
|
if (!asteriskGatewayUpP())
|
|
{ if (debug&DEBUG_GATEWAY) fprintf(stderr,"Asterisk gatway is not up, so not offering gateway.\n"); return -1; }
|
|
if (asteriskCreateExtension(requestor_sid,did,uri_out))
|
|
{
|
|
if (debug&DEBUG_GATEWAY) fprintf(stderr,"asteriskCreateExtension() failed, so not offering gateway.\n");
|
|
return -1;
|
|
}
|
|
if (asteriskWriteExtensions())
|
|
{
|
|
if (debug&DEBUG_GATEWAY) fprintf(stderr,"asteriskWriteExtensions() failed, so not offering gateway.\n");
|
|
return -1;
|
|
}
|
|
if (asteriskReloadExtensions())
|
|
{
|
|
if (debug&DEBUG_GATEWAY) fprintf(stderr,"asteriskReloadExtensions() failed, so not offering gateway.\n");
|
|
return -1;
|
|
}
|
|
if (debug&DEBUG_GATEWAY) fprintf(stderr,"asteriskReloadExtensions() suceeded, offering gateway.\n");
|
|
return 0;
|
|
}
|