socket.cpp

/*****************************************************************************
Portable Network Sockets Interface

This code should build out-of-the-box with no problems on:
   - UNIX boxes with Berkeley Sockets: Linux, Solaris, BSD, Mac OS X
   - Windows

This code can be compiled as C or C++ with no problems,
as long as both this file and the caller are compiled the same way.

Written by Orion Sky Lawlor, olawlor@acm.org 1999-2006 (Public Domain)
 *****************************************************************************/

#include "socket.h" /* osl/socket.h */

#include <stdio.h>
#include <errno.h>
#include <stdlib.h>
#include <string.h>
#include <signal.h>
#include <time.h>
#include <ctype.h>

/* socklen_t is needed by getsockname */
#if defined(socklen_t) || defined(_AIX) || defined(HAVE_SOCKLEN_T) || defined(CMK_HAS_SOCKLEN) || defined(__socklen_t_defined) || defined(_SOCKLEN_T)
  /* nothing needed--already have a socklen_t */
#else /* no socklen_t: define our own */
  typedef int socklen_t;
#endif

/*Just print out error message and exit*/
static int default_skt_abort(int code,const char *msg)
{
  fprintf(stderr,"Fatal socket error-- %s (%d)\n",msg,code);
  exit(1);
  return -1;
}

static skt_idleFn idleFunc=NULL;
static skt_abortFn skt_abort=default_skt_abort;
void skt_set_idle(skt_idleFn f) {idleFunc=f;}
skt_abortFn skt_set_abort(skt_abortFn f) 
{
	skt_abortFn old=skt_abort;
	skt_abort=f;
	return old;
}
int skt_call_abort(const char *msg) {
	return skt_abort(93999,msg);
}

/* These little flags are used to ignore the SIGPIPE signal
 * while we're inside one of our socket calls.
 * This lets us only handle SIGPIPEs we generated. */
static int skt_ignore_SIGPIPE=0;

/* Indicates the socket routines have already been initialized */
static int skt_inited=0;
#if defined(_WIN32) && !defined(__CYGWIN__) 
/************** Windows systems: call WSAStartup ****************/
static void doCleanup(void)
{ WSACleanup();}
/*Initialization routine (Windows only)*/
void skt_init(void)
{
  WSADATA WSAData;
  const static WORD version=0x0002;
  if (skt_inited) return;
  skt_inited=1;
  WSAStartup(version, &WSAData);
  atexit(doCleanup);
}

void skt_close(SOCKET fd)
{
	closesocket(fd);
}
#else 
/********** UNIX Systems: handle SIGPIPE *******************/

typedef void (*skt_signal_handler_fn)(int sig);
static skt_signal_handler_fn skt_fallback_SIGPIPE=NULL;
static void skt_SIGPIPE_handler(int sig) {
	if (skt_ignore_SIGPIPE) {
		fprintf(stderr,"Caught SIGPIPE.\n");
		signal(SIGPIPE,skt_SIGPIPE_handler);
	}
	else
		skt_fallback_SIGPIPE(sig);
}

void skt_init(void)
{
	if (skt_inited) return;
	skt_inited=1;
	/* Install a SIGPIPE signal handler.
	  This prevents us from dying when one of our network
	  connections goes down
	*/
	skt_fallback_SIGPIPE=signal(SIGPIPE,skt_SIGPIPE_handler);
}
void skt_close(SOCKET fd)
{
	skt_ignore_SIGPIPE=1;
	close(fd);
	skt_ignore_SIGPIPE=0;
}
#endif


/*Called when a socket or select routine returns
an error-- determines how to respond.
Return 1 if the last call was interrupted
by, e.g., an alarm and should be retried.
*/
static int skt_should_retry(void)
{
	int isinterrupt=0,istransient=0;
#if defined(_WIN32) && !defined(__CYGWIN__) /*Windows systems-- check Windows Sockets Error*/
	int err=WSAGetLastError();
	if (err==WSAEINTR) isinterrupt=1;
	if (err==WSATRY_AGAIN||err==WSAECONNREFUSED)
		istransient=1;
#else /*UNIX systems-- check errno*/
	int err=errno;
	if (err==EINTR) isinterrupt=1;
	if (err==EAGAIN||err==ECONNREFUSED||err==EWOULDBLOCK)
		istransient=1;
#endif
	if (isinterrupt) {
		/*We were interrupted by an alarm.  Schedule, then retry.*/
		if (idleFunc!=NULL) idleFunc();
	}
	else if (istransient)
	{ /*A transient error-- idle a while, then try again later.*/
		if (idleFunc!=NULL) idleFunc();
		else sleep(1);
	}
	else 
		return 0; /*Some unrecognized problem-- abort!*/
	return 1;/*Otherwise, we recognized it*/
}

/*Sleep on given read socket until msec or readable*/
int skt_select1(SOCKET fd,int msec)
{
  int sec=msec/1000;
  fd_set  rfds;
  struct timeval tmo, *tmp=&tmo;
  int  secLeft=sec;
  int  begin=0, nreadable;
  
  if (!skt_inited) skt_init();
  FD_ZERO(&rfds);
  FD_SET(fd, &rfds);

  if (msec>0) begin = time(0);
  else /* msec zero-- disable timeout */ tmp=NULL;
  do
  {
    tmo.tv_sec=secLeft;
    tmo.tv_usec = (msec-1000*sec)*1000;
    skt_ignore_SIGPIPE=1;
    nreadable = select(1+fd, &rfds, NULL, NULL, tmp);
    skt_ignore_SIGPIPE=0;
    
    if (nreadable < 0) {
		if (skt_should_retry()) continue;
		else return skt_abort(93200,"Fatal error in select");
	}
    if (nreadable >0) return 1; /*We gotta good socket*/
  }
  while(msec>0 && ((secLeft = sec - (time(0) - begin))>0));

  return 0;/*Timed out*/
}


/******* DNS *********/
skt_ip_t _skt_invalid_ip={{0}};

skt_ip_t skt_my_ip(void)
{
  char hostname[1000];
  
  if (!skt_inited) skt_init();
  if (gethostname(hostname, 999)==0)
      return skt_lookup_ip(hostname);

  return _skt_invalid_ip;
}

/* Parse an IP address like "137.229.25.100" */
static int skt_parse_dotted(const char *str,skt_ip_t *ret)
{
  unsigned int i;
  int v;
  *ret=_skt_invalid_ip;
  for (i=0;i<sizeof(skt_ip_t);i++) {
    if (1!=sscanf(str,"%d",&v)) return 0;
    if (v<0 || v>255) return 0;
    while (isdigit(*str)) str++; /* Advance over number */
    if (i!=sizeof(skt_ip_t)-1) { /*Not last time:*/
      if (*str!='.') return 0; /*Check for dot*/
    } else { /*Last time:*/
      if (*str!=0) return 0; /*Check for end-of-string*/
    }
    str++;
    ret->data[i]=(unsigned char)v;
  }
  // if (4==sscanf(str,"%d.%d.%d.%d",&a,&b,&c,&d)) return 1;
  return 1;
}

skt_ip_t skt_lookup_invalid(const char *name)
{
  skt_ip_t ret=_skt_invalid_ip;
  if (!skt_inited) skt_init();
  /*First try to parse the name as dotted decimal*/
  if (skt_parse_dotted(name,&ret))
    return ret;
  else {/*Try a DNS lookup*/
    struct hostent *h = gethostbyname(name);
    if (h==0) return _skt_invalid_ip;
    memcpy(&ret,h->h_addr_list[0],h->h_length);
    return ret;
  }
}

skt_ip_t skt_lookup_ip(const char *name)
{
  skt_ip_t ret=skt_lookup_invalid(name);
  if (skt_ip_match(_skt_invalid_ip,ret)) {
     char buf[1000];
     sprintf(buf,"Invalid domain name: '%s'\n",strlen(name)<900?name:"absurdly long name");
     skt_abort(99573,buf);
     return _skt_invalid_ip;
  }
  return ret;
}

/*Write as dotted decimal*/
char *skt_print_ip(char *dest,skt_ip_t addr)
{
  char *o=dest;
  unsigned int i;
  for (i=0;i<sizeof(addr);i++) {
    const char *trail=".";
    if (i==sizeof(addr)-1) trail=""; /*No trailing separator dot*/
    sprintf(o,"%d%s",(int)addr.data[i],trail);
    o+=strlen(o);
  }
  return dest;
}
int skt_ip_match(skt_ip_t a,skt_ip_t b)
{
  return 0==memcmp(&a,&b,sizeof(a));
}
struct sockaddr_in skt_build_addr(skt_ip_t IP,int port)
{
  struct sockaddr_in ret={0};
  if (!skt_inited) skt_init(); /* this works for datagram, server, and connect, too! */
  ret.sin_family=AF_INET;
  ret.sin_port = htons((short)port);
  memcpy(&ret.sin_addr,&IP,sizeof(IP));
  return ret;  
}

SOCKET skt_datagram(unsigned int *port, int bufsize)
{  
  int connPort=(port==NULL)?0:*port;
  struct sockaddr_in addr=skt_build_addr(_skt_invalid_ip,connPort);
  socklen_t          len;
  SOCKET             ret;
  
retry:
  ret = socket(AF_INET,SOCK_DGRAM,0);
  if (ret == SOCKET_ERROR) {
    if (skt_should_retry()) goto retry;  
    return skt_abort(93490,"Error creating datagram socket.");
  }
  if (bind(ret, (struct sockaddr *)&addr, sizeof(addr)) == SOCKET_ERROR)
	  return skt_abort(93491,"Error binding datagram socket.");
  
  len = sizeof(addr);
  if (getsockname(ret, (struct sockaddr *)&addr , &len))
	  return skt_abort(93492,"Error getting address on datagram socket.");

  if (bufsize) 
  {
    len = sizeof(int);
    if (setsockopt(ret, SOL_SOCKET , SO_RCVBUF , (char *)&bufsize, len) == SOCKET_ERROR) 
		return skt_abort(93495,"Error on RCVBUF sockopt for datagram socket.");
    if (setsockopt(ret, SOL_SOCKET , SO_SNDBUF , (char *)&bufsize, len) == SOCKET_ERROR) 
		return skt_abort(93496,"Error on SNDBUF sockopt for datagram socket.");
  }
  
  if (port!=NULL) *port = (int)ntohs(addr.sin_port);
  return ret;
}
SOCKET skt_server(unsigned int *port)
{
  return skt_server_ip(port,NULL);
}

SOCKET skt_server_ip(unsigned int *port,skt_ip_t *ip)
{
  SOCKET             ret;
  socklen_t          len;
  int on = 1; /* for setsockopt */
  int connPort=(port==NULL)?0:*port;
  struct sockaddr_in addr=skt_build_addr((ip==NULL)?_skt_invalid_ip:*ip,connPort);
  
retry:
  ret = socket(PF_INET, SOCK_STREAM, 0);
  
  if (ret == SOCKET_ERROR) {
    if (skt_should_retry()) goto retry;
    else return skt_abort(93483,"Error creating server socket.");
  }
  /* Prevents 3-minute socket reuse timeout after a server crash. */
  setsockopt(ret, SOL_SOCKET, SO_REUSEADDR, (const char *)&on, sizeof(on));
  
  if (bind(ret, (struct sockaddr *)&addr, sizeof(addr)) == SOCKET_ERROR) 
	  return skt_abort(93484,"Error binding server socket.  Is another process listening on that port already?");
  if (listen(ret,5) == SOCKET_ERROR) 
	  return skt_abort(93485,"Error listening on server socket.");
  len = sizeof(addr);
  if (getsockname(ret, (struct sockaddr *)&addr, &len) == SOCKET_ERROR) 
	  return skt_abort(93486,"Error getting name on server socket.");

  if (port!=NULL) *port = (int)ntohs(addr.sin_port);
  if (ip!=NULL) memcpy(ip, &addr.sin_addr, sizeof(*ip));
  return ret;
}

SOCKET skt_accept(SOCKET src_fd,skt_ip_t *pip, unsigned int *port)
{
  socklen_t len;
  struct sockaddr_in addr={0};
  SOCKET ret;
  len = sizeof(addr);
retry:
  ret = accept(src_fd, (struct sockaddr *)&addr, &len);
  if (ret == SOCKET_ERROR) {
    if (skt_should_retry()) goto retry;
    else return skt_abort(93523,"Error in accept.");
  }
  
  if (port!=NULL) *port=ntohs(addr.sin_port);
  if (pip!=NULL) memcpy(pip,&addr.sin_addr,sizeof(*pip));
  return ret;
}

SOCKET skt_connect(skt_ip_t ip, int port, int timeout)
{
  struct sockaddr_in addr=skt_build_addr(ip,port);
  int                ok, begin;
  SOCKET             ret;
  
  begin = time(0);
  while (time(0)-begin < timeout) 
  {
    ret = socket(AF_INET, SOCK_STREAM, 0);
    if (ret==SOCKET_ERROR) 
    {
	  if (skt_should_retry()) continue;  
      else return skt_abort(93512,"Error creating socket");
    }
    ok = connect(ret, (struct sockaddr *)&(addr), sizeof(addr));
    if (ok != SOCKET_ERROR) 
	  return ret;/*Good connect*/
	else { /*Bad connect*/
	  skt_close(ret);
	  if (skt_should_retry()) continue;
	  else return skt_abort(93515,"Error connecting to socket\n");
    }
  }
  /*Timeout*/
  return skt_abort(93517,"Timeout in socket connect\n");
}

void skt_setSockBuf(SOCKET skt, int bufsize)
{
  int len = sizeof(int);
  if (setsockopt(skt, SOL_SOCKET , SO_SNDBUF , (char *)&bufsize, len) == SOCKET_ERROR)
	skt_abort(93496,"Error on SNDBUF sockopt for datagram socket.");
  if (setsockopt(skt, SOL_SOCKET , SO_RCVBUF , (char *)&bufsize, len) == SOCKET_ERROR)
	skt_abort(93496,"Error on RCVBUF sockopt for datagram socket.");
}

int skt_recvN(SOCKET hSocket,void *buff,int nBytes)
{
  int nLeft,nRead;
  char *pBuff=(char *)buff;

  nLeft = nBytes;
  while (0 < nLeft)
  {
    if (0==skt_select1(hSocket,60*1000))
	return skt_abort(93610,"Timeout on socket recv!");
    skt_ignore_SIGPIPE=1;
    nRead = recv(hSocket,pBuff,nLeft,0);
    skt_ignore_SIGPIPE=0;
    if (nRead<=0)
    {
       if (nRead==0) return skt_abort(93620,"Socket closed before recv.");
       if (skt_should_retry()) continue;/*Try again*/
       else return skt_abort(93650+hSocket,"Error on socket recv!");
    }
    else
    {
      nLeft -= nRead;
      pBuff += nRead;
    }
  }
  return 0;
}

int skt_sendN(SOCKET hSocket,const void *buff,int nBytes)
{
  int nLeft,nWritten;
  const char *pBuff=(const char *)buff;
  
  nLeft = nBytes;
  while (0 < nLeft)
  {
    skt_ignore_SIGPIPE=1;
    nWritten = send(hSocket,pBuff,nLeft,0);
    skt_ignore_SIGPIPE=0;
    if (nWritten<=0)
    {
          if (nWritten==0) return skt_abort(93720,"Socket closed before send.");
	  if (skt_should_retry()) continue;/*Try again*/
	  else return skt_abort(93700+hSocket,"Error on socket send!");
    }
    else
    {
      nLeft -= nWritten;
      pBuff += nWritten;
    }
  }
  return 0;
}

/*Cheezy vector send: 
  really should use writev on machines where it's available. 
*/
#define skt_sendV_max (16*1024)

int skt_sendV(SOCKET fd,int nBuffers,const void **bufs,int *lens)
{
	int b,len=0;
	for (b=0;b<nBuffers;b++) len+=lens[b];
	if (len<=skt_sendV_max) { /*Short message: Copy and do one big send*/
		char *buf=(char *)malloc(skt_sendV_max);
		char *dest=buf;
		int ret;
		for (b=0;b<nBuffers;b++) {
			memcpy(dest,bufs[b],lens[b]);
			dest+=lens[b];
		}
		ret=skt_sendN(fd,buf,len);
		free(buf);
		return ret;
	}
	else { /*Big message: Just send one-by-one as usual*/
		int ret;
		for (b=0;b<nBuffers;b++) 
			if (0!=(ret=skt_sendN(fd,bufs[b],lens[b])))
				return ret;
		return 0;
	}
}