File content as of revision 1:1dd9b8218515:

#define __DEBUG__ 4

#ifndef __MODULE__
#define __MODULE__ "main.cpp"
#endif

#include "mbed.h"
#include "rtos.h"
#include "bsd_socket.h"

#include <dtls.h>
#include "global.h"
#include "debug.h"
#include "errno.h"

#include "VodafoneUSBModem.h"
DigitalOut myled(LED1);

void fail(int code) {
   while(1) {
      myled = !myled;
      Thread::wait(100);
   }
}

/* This function is the "key store" for tinyDTLS. It is called to
 * retrieve a key for the given identiy within this particular
 * session. */
int get_key(struct dtls_context_t *ctx, 
    const session_t *session, 
    const unsigned char *id, size_t id_len, 
    const dtls_key_t **result) {
    DBG("get_key called");

  static const dtls_key_t psk = {
    .type = DTLS_KEY_PSK,
    .key.psk.id = (unsigned char *)"Client_identity", 
    .key.psk.id_length = 15,
    .key.psk.key = (unsigned char *)"secretPSK", 
    .key.psk.key_length = 9
  };
   
  *result = &psk;
  return 0;
}

//#define APN_GDSP
#define APN_CONTRACT

#ifdef APN_GDSP
   #define APN "ppinternetd.gdsp" 
   #define APN_USERNAME ""
   #define APN_PASSWORD ""
#endif

#ifdef APN_CONTRACT
   #define APN "internet" 
   #define APN_USERNAME "web"
   #define APN_PASSWORD "web"
#endif

// globals
int gDTLSConnected = 0;
sockaddr_in bindAddr,serverAddress;

// this is used to setup sockaddr_in structures for a remote host
// it also listens for incoming UDP packets on the local interface on port
bool connectToSocketUDP(char *ipAddress, int port, int *sockfd) {
  *sockfd = -1;
  // create the socket
  if((*sockfd=socket(AF_INET,SOCK_DGRAM,0))<0) {
     DBG("Error opening socket");
     return false;
  }
  socklen_t sockAddrInLen = sizeof(struct sockaddr_in);
   
  // bind socket to 11111
  memset(&bindAddr,  0x00, sockAddrInLen);
  bindAddr.sin_family = AF_INET; // IP family
  bindAddr.sin_port = htons(port);
  bindAddr.sin_addr.s_addr = IPADDR_ANY; // 32 bit IP representation
  // call bind
  if(bind(*sockfd,(const struct sockaddr *)&bindAddr,sockAddrInLen)!=0) {
     DBG("Error binding socket");
     perror(NULL);
  }

  INFO("UDP socket created and bound to: %s:%d",inet_ntoa(bindAddr.sin_addr),ntohs(bindAddr.sin_port));
         
  // create the socket address
  memset(&serverAddress, 0x00, sizeof(struct sockaddr_in));
  serverAddress.sin_addr.s_addr = inet_addr(ipAddress);
  serverAddress.sin_family = AF_INET;
  serverAddress.sin_port = htons(port);

  // do socket connect
  //LOG("Connecting socket to %s:%d", inet_ntoa(serverAddress.sin_addr), ntohs(serverAddress.sin_port));
  if(connect(*sockfd, (const struct sockaddr *)&serverAddress, sizeof(serverAddress))<0) {
     shutdown(*sockfd,SHUT_RDWR);
     close(*sockfd);
     DBG("Could not connect");
     return false;
  }
  return true;
}
// this is a required callback for tinydtls it is called
// whenever tinydtls handles a raw buffer through dtls_handle_message.
// tinydtls extracts the unencrypted data and passes it onto this function
int read_from_peer(struct dtls_context_t *ctx, session_t *session, uint8 *data, size_t len) {
  DBG("read_from_peer called");
  size_t i;
  for (i = 0; i < len; i++)
    printf("%c", data[i]);
  return 0;
}

/// this is a required callback for tinydtls it is called
// whenever tinydtls needs to send a raw buffer (i.e whenever dtls_write is called by the application)
int send_to_peer(struct dtls_context_t *ctx, session_t *session, uint8 *data, size_t len) {
  DBG("send_to_peer called");
  int fd = *(int *)dtls_get_app_data(ctx);
  return sendto(fd, data, len, MSG_DONTWAIT,
        &session->addr.sa, session->size);
}

// this is used to handle incoming packets for tinydtls
// raw buffers are passed to dtls_handle_message, who
// processes them and passes the data onto the read callback
int dtls_handle_read(struct dtls_context_t *ctx) {
  DBG("dtls_handle_read called");
  int fd;
  session_t session;
  #define MAX_READ_BUF 256
  static uint8 buf[MAX_READ_BUF];
  int len;

  fd = *(int *)dtls_get_app_data(ctx);

  memset(&session, 0, sizeof(session_t));
  session.size = sizeof(session.addr);
  len = recvfrom(fd, buf, MAX_READ_BUF, 0, 
         &session.addr.sa, &session.size);
  
  if(len < 0) {
    DBG("Got nothing from read");
    perror("recvfrom");
    return -1;
  } else {
    #if __DEBUG__ > 0
    unsigned char addrbuf[72];
    dsrv_print_addr(&session, addrbuf, sizeof(addrbuf));
    DBG("Got %d bytes from %s", len, (char *)addrbuf);
    dump((unsigned char *)&session, sizeof(session_t));
    DBGX("\r\n");
    dump(buf, len);
    DBGX("\r\n");
    #endif
  }

  return dtls_handle_message(ctx, &session, buf, len);
} 

// callback called on tinydtls events (currently only ever called for DTLS_EVENT_CONNECTED)
int event_handler(
   struct dtls_context_t *ctx,
   session_t *session, 
   dtls_alert_level_t level,
   unsigned short code) {
   DBG("DTLS SESSION SETUP COMPLETE");
   gDTLSConnected = 1;
   return 0;
}

// structure for required tinydtls callbacks
static dtls_handler_t cb = {
  .write = send_to_peer,
  .read  = read_from_peer,
  .event = event_handler,
  .get_key = get_key
};

int main() {
    DBG_INIT();
    DBG_SET_SPEED(115200);
    DBG_SET_NEWLINE("\r\n");
    
    DBG("Tiny DTLS test");

    // DTLS context struct    
    dtls_context_t *dtls_context = NULL;
    int ret = 0, counter = 0;
    fd_set rfds, wfds;
    struct timeval timeout;
    char outBuf[64];
    
    // structure for getting address of incoming packets
    sockaddr_in fromAddr;
    socklen_t fromAddrLen = sizeof(struct sockaddr_in);
    memset(&fromAddr,0x00,fromAddrLen);
    
    // connect to cellular network
    VodafoneUSBModem modem;
    modem.connect(APN,APN_USERNAME,APN_PASSWORD);

    // setup socket to remote server
    int sockfd = NULL;
    if(!connectToSocketUDP("109.74.199.96", 5683, &sockfd)) {
       DBG("Error connecting to socket");
       fail(1);
    }
    DBG("\"Connected\" to UDP socket");
    int on = 1;
    if(setsockopt(sockfd, SOL_SOCKET, SO_REUSEADDR, &on, sizeof(on) ) < 0) {
       DBG("setsockopt SO_REUSEADDR: %s", strerror(errno));
    }
    
    // tinydtls stuff
    
    // destination address is stored in a session type
    session_t dst;
    memset(&dst, 0, sizeof(session_t));
    dst.size = sizeof(sockaddr_in);
    serverAddress.sin_len  = dst.size;
    memcpy(&dst.addr.sa, &serverAddress, dst.size);
    //dst.addr.sin.sin_port = htons(4433);
    
    // dtls init must always be called for memory allocation
    dtls_init();
    dtls_set_log_level(LOG_DEBUG);
    // setup DTLS context
    DBG("Creating DTLS context");
    dtls_context = dtls_new_context(&sockfd);
    if(!dtls_context) {
       DBG("Cannot create context");
       fail(3);
    }
    DBG("DTLS context created");
    
    // forced to use this call back system
    
    dtls_set_handler(dtls_context, &cb);
    
    DBG("Issuing dtls_connect");
    ret = dtls_connect(dtls_context, &dst);
    if(ret<0) {
       DBG("Error in dtls_connect: %d",ret);
       modem.disconnect();
       fail(4);
    }
    if(ret==0) {
       DBG("Channel already exists");
       modem.disconnect();
       fail(5);
    }
    DBG("dtls_connect successfull");
    while (1) {
        // setup file descriptor lists for select
        FD_ZERO(&rfds);
        FD_ZERO(&wfds);
        //FD_SET(fileno(stdin), &rfds);
        FD_SET(sockfd, &rfds);
        // FD_SET(sockfd, &wfds);
    
        timeout.tv_sec = 5;
        timeout.tv_usec = 0;
    
        int result = select(sockfd+1, &rfds, &wfds, 0, &timeout);
    
        if(result < 0) { // error
        if (errno != EINTR)
            perror("select");
        } else if (result == 0) {
           // timeout
           DBG("select timeout");
           // if we are connected, send some random data (every time select times out)
           // heh, abusing select as a timer
           if(gDTLSConnected) {
              sprintf(outBuf,"This is a pointless test message: %d\r\n",counter++);
              dtls_write(dtls_context, &dst, (uint8 *)outBuf, strlen(outBuf));
              //try_send(dtls_context, &dst);
           }
        } else {
           // OK
           // check which file descriptor had an event
           if(FD_ISSET(sockfd, &wfds)) {
              // FIXME (from tinydtls)
           } else if (FD_ISSET(sockfd, &rfds))
              if(dtls_handle_read(dtls_context)<0) {
                 modem.disconnect();
                 fail(6);
              }
           } 
        //else if (FD_ISSET(fileno(stdin), &rfds))
           //handle_stdin();
        //}

       
  }

}