eagi_proxy.c

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/*
 * Asterisk EAGI -> TCP/IP proxy
 *  by Danijel Korzinek (devil_slayer _at_ hotmail.com)
 *
 * This simple C application allows you to control asterisk thru one TCP/IP
 * socket and listen to the conversation thru another socket.
 *
 * Great for ASR or wizzard-of-oz telephony systems!
 *
 * HOWTO:
 *  The program is compiled using the following command:
 *      gcc eagi_proxy.c -o eagi_proxy -lpthread
 *
 *  In the dialplan, you can add something like this to the main context:
 *      exten => s,1,Answer
 *      exten => s,n,EAGI(/path/to/eagi_proxy)
 *      exten => s,n,Hangup
 *
 *  To test the program you can use the netcat utility:
 *      (http://netcat.sourceforge.net/)
 *
 *      -in one console run:
 *          nc -vv -l -p 8418 > /path/to/file.raw
 *      -in another run:
 *          nc -vv -l -p 8417
 *      -you can use any file for the signal or even /dev/null
 *      -you can change the port numbers in the sourcecode below
 *
 *  Once you make the call, both programs will accept the incoming
 *  connection. The program on port 8417 will print out the enviornemnt
 *  (unless the appropriate define below is commented) and you can write
 *  any AGI command there (http://www.voip-info.org/wiki-Asterisk+AGI),
 *  e.g.:
 *      GET DATA /path/to/gsm/file 10000 4
 *
 *  Finally, you can open the RAW file in any sound editor. The format is:
 *      RAW little-endian 8kHz 16bit
 */
 
#include <stdlib.h>
#include <unistd.h>
#include <stdio.h>
#include <netinet/in.h>
#include <netinet/tcp.h>
#include <string.h>
#include <time.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <sys/socket.h>
#include <sys/time.h>
#include <arpa/inet.h>
#include <netdb.h>
#include <fcntl.h>
#include <errno.h>
#include <ctype.h>
#include <pthread.h>
 
/* DEFINES */
#define SIGNAL_PORT 8418
#define COMMAND_PORT 8417
#define SEND_ENVIORNMENT /*send the enviornment thru the socket*/
/************************/
 
 
#define BUFSIZE 1024
char buf[BUFSIZE];
 
#define WINSIZE 400 /* 25 ms @ 8 kHz and 16bit */
char window[WINSIZE];
 
#define WINBUF_NUM 2400 /* number of WINSIZE windows = 1 minute */
char* winbuf;
char *end, *bs, *be;
/* winbuf - start of buffer
 * end - end of buffer
 * bs - start of data
 * be - end of data
 */
 
int command_desc; /* command transfer descriptor */
int speech_desc; /* speech signal descrriptor */
char connected=1; /* connection state */
 
int connect_to_host(char* host, int port); /* connect to a given host (name or IP) and given port number in nonblocking mode returning socket descriptor*/
 
void read_full(int file, char* buffer, int num); /* read EXACTLY "num" ammount of bytes from "file" descriptor to "buffer"*/
int read_some(int file, char* buffer, int size); /* read AT MOST "size" ammount of bytes */
 
void write_buf(int file, char* buffer, int num); /* write "num" ammount of bytes to "file" descriptor and buffer the surplus if the write would block */
int write_amap(int file, char* buffer, int num); /*write AT MOST "num" ammount of bytes and return ammount that was written*/
 
void setnonblocking(int desc); /*sets the socket non-blocking; for polling */
 
void finalize(); /* this function is run at exit */
 
pthread_mutex_t command_mutex;/* command socket mutex */
pthread_t stdin_thread,signal_thread;
void* readStdin(void* ptr);
void* readSignal(void* ptr);
 
/* The program creates 3 threads:
 * 1) Main thread - reads commands from the socket and sends them to asterisk
 * 2) stdin_thread - reads asterisk output and sends it to the command socket
 * 3) signal_thread - reads the sound from asterisk and sends it to the signal socket
 */
 
int main()
{
    int ret;
 
    atexit(finalize);
 
    setlinebuf(stdin);
    setlinebuf(stdout);
 
    winbuf=(char*)malloc(WINSIZE*WINBUF_NUM);
    end=winbuf+WINSIZE*WINBUF_NUM;
    bs=be=winbuf;
 
    speech_desc=connect_to_host("localhost",SIGNAL_PORT);
    if(speech_desc<0)
    {
        perror("signal socket");
        return -1;
    }
 
 
    command_desc=connect_to_host("localhost",COMMAND_PORT);
    if(command_desc<0)
    {
        perror("command socket");
        return -1;
    }
 
    pthread_mutex_init(&command_mutex,NULL);
    pthread_create(&stdin_thread,NULL,readStdin,NULL);
    pthread_create(&signal_thread,NULL,readSignal,NULL);
 
    while(connected)
    {
        pthread_mutex_lock(&command_mutex);
        ret=read_some(command_desc,buf,BUFSIZE);
        pthread_mutex_unlock(&command_mutex);
        if(ret>0)
        {
            buf[ret]=0;
            printf("%s",buf);
        }
    }
 
    return 0;
}
 
void finalize()
{
    close(command_desc);
    close(speech_desc);
    free(winbuf);
}
 
void* readStdin(void* ptr)
{
    while(1)/*read enviornment*/
    {
        fgets(buf,BUFSIZE,stdin);
        #ifdef SEND_ENVIORNMENT
            pthread_mutex_lock(&command_mutex);
            write_buf(command_desc,buf,strlen(buf));
            pthread_mutex_unlock(&command_mutex);
        #endif
        if(feof(stdin) || buf[0]=='\n')
        {
            break;
        }
    }
 
    while(connected)
    {
        fgets(buf,BUFSIZE,stdin);
        pthread_mutex_lock(&command_mutex);
        write_buf(command_desc,buf,strlen(buf));
        pthread_mutex_unlock(&command_mutex);
    }
 
    pthread_exit(NULL);
}
 
void* readSignal(void* ptr)
{
    while(connected)
    {
        read_full(3,window,WINSIZE);
        write_buf(speech_desc,window,WINSIZE);
    }
 
    pthread_exit(NULL);
}
 
 
void read_full(int file, char* buffer, int num)
{
    int count,pos=0;
 
    while(num)
    {
        count=read(file,buffer+pos,num);
        if(count==0 || (count<0 && errno!=EAGAIN))
        {
            connected=0;
            return;
        }
        num-=count;
        pos+=count;
    }
}
 
int connect_to_host(char* name, int port)
{
    int address;
    struct hostent* host_entity;
    int res,desc;
    int opts;
    struct sockaddr_in host;
 
 
    /* get address */
    if(!strcmp(name,"localhost"))
        address=htonl(2130706433); /*127.0.0.1*/
    else
    {
        address=inet_addr(name); /* check if it's an IP that's written in the string */
        if(address==(in_addr_t)-1)
        {
            host_entity = gethostbyname(name); /* search for the host under this name */
 
            if(!host_entity)
            {
                fprintf(stderr,"EAGI proxy: Wrong address!\n"); /* can't find anything*/
                return -1;
            }
            address=*((int*)host_entity->h_addr);
        }
    }
 
    desc=socket(AF_INET,SOCK_STREAM,IPPROTO_TCP);
    if(desc<0)
    {
        fprintf(stderr,"EAGI proxy: Cannot create socket!\n");
        return -1;
    }
 
    memset((void*)&host,0,sizeof(struct sockaddr_in));
 
    host.sin_family=AF_INET;
    host.sin_port=htons(port);
    host.sin_addr.s_addr=address;
 
    res=connect(desc,(struct sockaddr*)&host,sizeof(host));
    if(res<0)
    {
        fprintf(stderr,"EAGI proxy: Cannot connect!\n");
        return -1;
    }
 
    /* set to non-blocking mode */
    opts = fcntl(desc,F_GETFL);
    if (opts < 0) {
        perror("fcntl(F_GETFL)");
        exit(EXIT_FAILURE);
    }
    opts = (opts | O_NONBLOCK);
    if (fcntl(desc,F_SETFL,opts) < 0) {
        perror("fcntl(F_SETFL)");
        exit(EXIT_FAILURE);
    }
 
 
    return desc;
}
 
int read_some(int desc, char* buffer, int size)
{
    unsigned char c;
    int res,i=0;
 
    for(;;)
    {
        res=read(desc,&c,1);
        if(res<1)
        {
            if(errno!=EAGAIN)
            {
                perror("Error reading");
                connected=0;
            }
            break;
        }
        if(res==0)
        {
            connected=0;
            break;
        }
 
        buffer[i]=c;
        i++;
    }
 
    return i;
}
 
/* This is a tricky function! */
void write_buf(int desc, char* buf, int size)
{
    int ret;
 
    /*NOTE: AMAP -> as much as possible */
 
    if(be!=bs)/* if data left in buffer */
    {
        if(be>bs)/* if buffer not split */
        {
            ret=write_amap(desc,bs,be-bs);/* write AMAP */
            bs+=ret;/* shift the start of the buffer */
        }
        else/* if buffer is split */
        {
            ret=write_amap(desc,bs,end-bs);/* write higher part first */
            if(ret==end-bs)/* if wrote whole of the higher part */
            {
                ret=write_amap(desc,winbuf,be-winbuf);/* write lower part */
                bs=winbuf+ret;/* shift start to new position */
            }
            else bs+=ret;/* if not wrote whole of higher part, only shift start */
        }
    }
 
    if(be==bs)/* if buffer is empty now */
    {
        ret=write_amap(desc,buf,size);/* write AMAP of the new data */
        buf+=ret;/* shift start of new data */
        size-=ret;/* lower size of new data */
    }
 
    if(size)/* if new data still remains unsent */
    {
        if(be>=bs)/* if data not split */
        {
            if(size>end-be)/* if new data size doesn't fit higher end */
            {
                size-=end-be;/* reduce new data size by the higher end size */
                memcpy(be,buf,end-be);/* copy to higher end */
                be=winbuf;/* shift end to begining of buffer */
                buf+=end-be;/* shift start of new data */
            }
            else/* if new data fits the higher end */
            {
                memcpy(be,buf,size);/* copy to higher end */
                be+=size;/* shift end by size */
                if(be>=end)/* if end goes beyond the buffer */
                    be=winbuf;/* restart */
                size=0;/* everything copied */
            }
        }
 
        if(size)/* if new data still remains */
        {
            if(size>=bs-be)/* if new data doesn't fit between end and start */
            {
                fprintf(stderr,"Buffer overflow!\n");
                size=bs-be-1;/* reduce the size that we can copy */
            }
 
            if(size)/* if we can copy anything */
            {
                memcpy(be,buf,size);/* copy the new data between end and start */
                be+=size;/* shift end by size */
            }
        }
    }
}
 
int write_amap(int desc, char* buf, int size)
{
    int ret;
    ret=write(desc,buf,size);
    if(ret<0)
    {
        if(errno!=EAGAIN)
        {
            perror("Error writing");
            connected=0;
        }
        return 0;
    }
    if(ret==0)
        connected=0;
 
    return ret;
}
 
 
void setnonblocking(int desc)
{
    int opts;
 
    opts = fcntl(desc,F_GETFL);
    if(opts < 0)
    {
        perror("fcntl(F_GETFL)");
        exit(-1);
    }
 
    opts = (opts | O_NONBLOCK );
    if(fcntl(desc,F_SETFL,opts) < 0)
    {
        perror("fcntl(F_SETFL)");
        exit(-1);
    }
}