udp.cc File Reference

#include <cassert>
#include <cstdio>
#include <cstring>
#include <errno.h>
#include <iostream>
#include <cstdlib>
#include <time.h>
#include <arpa/inet.h>
#include <stdlib.h>
#include <unistd.h>
#include <fcntl.h>
#include <netinet/in.h>
#include <sys/socket.h>
#include <sys/types.h>
#include <netdb.h>
#include <string.h>
#include "udp.h"

Functions

Socket openPort (unsigned short port, unsigned int interfaceIp, bool verbose)
 Open a UDP socket to receive on the given port - if port is 0, pick a a port, if interfaceIp!=0 then use ONLY the interface specified instead of all of them.
bool getMessage (Socket fd, char *buf, int *len, unsigned int *srcIp, unsigned short *srcPort, bool verbose)
 recive a UDP message
bool sendMessage (Socket fd, char *buf, int l, unsigned int dstIp, unsigned short dstPort, bool verbose)
 send a UDP message
void initNetwork ()
 set up network - does nothing in unix but needed for windows


Function Documentation

bool getMessage ( Socket  fd,
char *  buf,
int *  len,
unsigned int *  srcIp,
unsigned short *  srcPort,
bool  verbose 
)

recive a UDP message

Referenced by stunNatType(), stunOpenSocket(), stunOpenSocketPair(), stunServerProcess(), and stunTest().

00117 {
00118    assert( fd != INVALID_SOCKET );
00119         
00120    int originalSize = *len;
00121    assert( originalSize > 0 );
00122    
00123    struct sockaddr_in from;
00124    int fromLen = sizeof(from);
00125         
00126    *len = recvfrom(fd,
00127                    buf,
00128                    originalSize,
00129                    0,
00130                    (struct sockaddr *)&from,
00131                    (socklen_t*)&fromLen);
00132         
00133    if ( *len == SOCKET_ERROR )
00134    {
00135       int err = getErrno();
00136                 
00137       switch (err)
00138       {
00139          case ENOTSOCK:
00140             cerr << "Error fd not a socket" <<   endl;
00141             break;
00142          case ECONNRESET:
00143             cerr << "Error connection reset - host not reachable" <<   endl;
00144             break;
00145                                 
00146          default:
00147             cerr << "Socket Error=" << err << endl;
00148       }
00149                 
00150       return false;
00151    }
00152         
00153    if ( *len < 0 )
00154    {
00155       clog << "socket closed? negative len" << endl;
00156       return false;
00157    }
00158     
00159    if ( *len == 0 )
00160    {
00161       clog << "socket closed? zero len" << endl;
00162       return false;
00163    }
00164     
00165    *srcPort = ntohs(from.sin_port);
00166    *srcIp = ntohl(from.sin_addr.s_addr);
00167         
00168    if ( (*len)+1 >= originalSize )
00169    {
00170       if (verbose)
00171       {
00172          clog << "Received a message that was too large" << endl;
00173       }
00174       return false;
00175    }
00176    buf[*len]=0;
00177     
00178    return true;
00179 }

void initNetwork (  ) 

set up network - does nothing in unix but needed for windows

00259 {
00260 #ifdef WIN32 
00261    WORD wVersionRequested = MAKEWORD( 2, 2 );
00262    WSADATA wsaData;
00263    int err;
00264         
00265    err = WSAStartup( wVersionRequested, &wsaData );
00266    if ( err != 0 ) 
00267    {
00268       // could not find a usable WinSock DLL
00269       cerr << "Could not load winsock" << endl;
00270       assert(0); // is this is failing, try a different version that 2.2, 1.0 or later will likely work 
00271       exit(1);
00272    }
00273     
00274    /* Confirm that the WinSock DLL supports 2.2.*/
00275    /* Note that if the DLL supports versions greater    */
00276    /* than 2.2 in addition to 2.2, it will still return */
00277    /* 2.2 in wVersion since that is the version we      */
00278    /* requested.                                        */
00279     
00280    if ( LOBYTE( wsaData.wVersion ) != 2 ||
00281         HIBYTE( wsaData.wVersion ) != 2 ) 
00282    {
00283       /* Tell the user that we could not find a usable */
00284       /* WinSock DLL.                                  */
00285       WSACleanup( );
00286       cerr << "Bad winsock verion" << endl;
00287       assert(0); // is this is failing, try a different version that 2.2, 1.0 or later will likely work 
00288       exit(1);
00289    }    
00290 #endif
00291 }

Socket openPort ( unsigned short  port,
unsigned int  interfaceIp,
bool  verbose 
)

Open a UDP socket to receive on the given port - if port is 0, pick a a port, if interfaceIp!=0 then use ONLY the interface specified instead of all of them.

Referenced by stunInitServer(), stunNatType(), stunOpenSocket(), stunOpenSocketPair(), stunServerProcess(), and stunTest().

00039 {
00040    Socket fd;
00041     
00042    fd = socket(PF_INET, SOCK_DGRAM, IPPROTO_UDP);
00043    if ( fd == INVALID_SOCKET )
00044    {
00045       int err = getErrno();
00046       cerr << "Could not create a UDP socket:" << err << endl;
00047       return INVALID_SOCKET;
00048    }
00049     
00050    struct sockaddr_in addr;
00051    memset((char*) &(addr),0, sizeof((addr)));
00052    addr.sin_family = AF_INET;
00053    addr.sin_addr.s_addr = htonl(INADDR_ANY);
00054    addr.sin_port = htons(port);
00055     
00056    if ( (interfaceIp != 0) && 
00057         ( interfaceIp != 0x100007f ) )
00058    {
00059       addr.sin_addr.s_addr = htonl(interfaceIp);
00060       if (verbose )
00061       {
00062          clog << "Binding to interface " 
00063               << hex << "0x" << htonl(interfaceIp) << dec << endl;
00064       }
00065    }
00066         
00067    if ( bind( fd,(struct sockaddr*)&addr, sizeof(addr)) != 0 )
00068    {
00069       int e = getErrno();
00070         
00071       switch (e)
00072       {
00073          case 0:
00074          {
00075             cerr << "Could not bind socket" << endl;
00076             return INVALID_SOCKET;
00077          }
00078          case EADDRINUSE:
00079          {
00080             cerr << "Port " << port << " for receiving UDP is in use" << endl;
00081             return INVALID_SOCKET;
00082          }
00083          break;
00084          case EADDRNOTAVAIL:
00085          {
00086             if ( verbose ) 
00087             {
00088                cerr << "Cannot assign requested address" << endl;
00089             }
00090             return INVALID_SOCKET;
00091          }
00092          break;
00093          default:
00094          {
00095             cerr << "Could not bind UDP receive port"
00096                  << "Error=" << e << " " << strerror(e) << endl;
00097             return INVALID_SOCKET;
00098          }
00099          break;
00100       }
00101    }
00102    if ( verbose )
00103    {
00104       clog << "Opened port " << port << " with fd " << fd << endl;
00105    }
00106    
00107    assert( fd != INVALID_SOCKET  );
00108         
00109    return fd;
00110 }

bool sendMessage ( Socket  fd,
char *  buf,
int  l,
unsigned int  dstIp,
unsigned short  dstPort,
bool  verbose 
)

send a UDP message

Referenced by stunSendTest(), and stunServerProcess().

00186 {
00187    assert( fd != INVALID_SOCKET );
00188     
00189    int s;
00190    if ( dstPort == 0 )
00191    {
00192       // sending on a connected port 
00193       assert( dstIp == 0 );
00194                 
00195       s = send(fd,buf,l,0);
00196    }
00197    else
00198    {
00199       assert( dstIp != 0 );
00200       assert( dstPort != 0 );
00201         
00202       struct sockaddr_in to;
00203       int toLen = sizeof(to);
00204       memset(&to,0,toLen);
00205         
00206       to.sin_family = AF_INET;
00207       to.sin_port = htons(dstPort);
00208       to.sin_addr.s_addr = htonl(dstIp);
00209         
00210       s = sendto(fd, buf, l, 0,(sockaddr*)&to, toLen);
00211    }
00212     
00213    if ( s == SOCKET_ERROR )
00214    {
00215       int e = getErrno();
00216       switch (e)
00217       {
00218          case ECONNREFUSED:
00219          case EHOSTDOWN:
00220          case EHOSTUNREACH:
00221          {
00222             // quietly ignore this 
00223          }
00224          break;
00225          case EAFNOSUPPORT:
00226          {
00227             cerr << "err EAFNOSUPPORT in send" << endl;
00228          }
00229          break;
00230          default:
00231          {
00232             cerr << "err " << e << " "  << strerror(e) << " in send" << endl;
00233          }
00234       }
00235       return false;
00236    }
00237     
00238    if ( s == 0 )
00239    {
00240       cerr << "no data sent in send" << endl;
00241       return false;
00242    }
00243     
00244    if ( s != l )
00245    {
00246       if (verbose)
00247       {
00248          cerr << "only " << s << " out of " << l << " bytes sent" << endl;
00249       }
00250       return false;
00251    }
00252     
00253    return true;
00254 }


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