예제 #1
0
파일: xio-udp.c 프로젝트: erluko/socat
/* we expect the form: port */
int xioopen_ipdgram_listen(int argc, const char *argv[], struct opt *opts,
			   int xioflags, xiofile_t *fd,
			  unsigned groups, int pf, int ipproto,
			  int protname) {
   const char *portname = argv[1];
   union sockaddr_union us;
   union sockaddr_union themunion;
   union sockaddr_union *them = &themunion;
   int socktype = SOCK_DGRAM;
   struct pollfd readfd;
   bool dofork = false;
   pid_t pid;
   char *rangename;
   char infobuff[256];
   unsigned char buff1[1];
   socklen_t uslen;
   socklen_t themlen;
   int result;

   if (argc != 2) {
      Error2("%s: wrong number of parameters (%d instead of 1)", argv[0], argc-1);
   }

   if (pf == PF_UNSPEC) {
#if WITH_IP4 && WITH_IP6
      pf = xioopts.default_ip=='6'?PF_INET6:PF_INET;
#elif WITH_IP6
      pf = PF_INET6;
#else
      pf = PF_INET;
#endif
   }

   retropt_socket_pf(opts, &pf);

   if (applyopts_single(&fd->stream, opts, PH_INIT) < 0)  return -1;
   applyopts(-1, opts, PH_INIT);

   uslen = socket_init(pf, &us);
   retropt_bind(opts, pf, socktype, IPPROTO_UDP,
		(struct sockaddr *)&us, &uslen, 1,
		fd->stream.para.socket.ip.res_opts[1],
		fd->stream.para.socket.ip.res_opts[0]);

   if (false) {
      ;
#if WITH_IP4
   } else if (pf == PF_INET) {
      us.ip4.sin_port = parseport(portname, ipproto);
#endif
#if WITH_IP6
   } else if (pf == PF_INET6) {
      us.ip6.sin6_port = parseport(portname, ipproto);
#endif
   } else {
      Error1("xioopen_ipdgram_listen(): unknown address family %d", pf);
   }

   retropt_bool(opts, OPT_FORK, &dofork);

   if (dofork) {
      if (!(xioflags & XIO_MAYFORK)) {
	 Error("option fork not allowed here");
	 return STAT_NORETRY;
      }
   }

#if WITH_IP4 /*|| WITH_IP6*/
   if (retropt_string(opts, OPT_RANGE, &rangename) >= 0) {
      if (xioparserange(rangename, pf, &fd->stream.para.socket.range) < 0) {
	 free(rangename);
	 return STAT_NORETRY;
      }
      free(rangename);
      fd->stream.para.socket.dorange = true;
   }
#endif

#if WITH_LIBWRAP
   xio_retropt_tcpwrap(&fd->stream, opts);
#endif /* WITH_LIBWRAP */

   if (retropt_ushort(opts, OPT_SOURCEPORT, &fd->stream.para.socket.ip.sourceport)
       >= 0) {
      fd->stream.para.socket.ip.dosourceport = true;
   }
   retropt_bool(opts, OPT_LOWPORT, &fd->stream.para.socket.ip.lowport);

   if (dofork) {
      xiosetchilddied();	/* set SIGCHLD handler */
   }

   while (true) {	/* we loop with fork or prohibited packets */
      /* now wait for some packet on this datagram socket, get its sender
	 address, connect there, and return */
      int one = 1;
      char infobuff[256];
      union sockaddr_union _sockname;
      union sockaddr_union *la = &_sockname;	/* local address */

      if ((fd->stream.fd = xiosocket(opts, pf, socktype, ipproto, E_ERROR)) < 0) {
	 return STAT_RETRYLATER;
      }
      applyopts(fd->stream.fd, opts, PH_PASTSOCKET);
      if (Setsockopt(fd->stream.fd, opt_so_reuseaddr.major,
		     opt_so_reuseaddr.minor, &one, sizeof(one)) < 0) {
	 Warn6("setsockopt(%d, %d, %d, {%d}, "F_Zd"): %s",
	       fd->stream.fd, opt_so_reuseaddr.major,
	       opt_so_reuseaddr.minor, one, sizeof(one), strerror(errno));
      }
      applyopts_cloexec(fd->stream.fd, opts);
      applyopts(fd->stream.fd, opts, PH_PREBIND);
      applyopts(fd->stream.fd, opts, PH_BIND);
      if (Bind(fd->stream.fd, &us.soa, uslen) < 0) {
	 Error4("bind(%d, {%s}, "F_Zd"): %s", fd->stream.fd,
		sockaddr_info(&us.soa, uslen, infobuff, sizeof(infobuff)),
		uslen, strerror(errno));
	 return STAT_RETRYLATER;
      }
      /* under some circumstances bind() fills sockaddr with interesting info. */
      if (Getsockname(fd->stream.fd, &us.soa, &uslen) < 0) {
	 Error4("getsockname(%d, %p, {%d}): %s",
		fd->stream.fd, &us.soa, uslen, strerror(errno));
      }
      applyopts(fd->stream.fd, opts, PH_PASTBIND);

      Notice1("listening on UDP %s",
	      sockaddr_info(&us.soa, uslen, infobuff, sizeof(infobuff)));
      readfd.fd = fd->stream.fd;
      readfd.events = POLLIN|POLLERR;
      while (xiopoll(&readfd, 1, NULL) < 0) {
	 if (errno != EINTR)  break;
      }

      themlen = socket_init(pf, them);
      do {
	 result = Recvfrom(fd->stream.fd, buff1, 1, MSG_PEEK,
			     &them->soa, &themlen);
      } while (result < 0 && errno == EINTR);
      if (result < 0) {
	 Error5("recvfrom(%d, %p, 1, MSG_PEEK, {%s}, {"F_Zu"}): %s",
		fd->stream.fd, buff1,
		sockaddr_info(&them->soa, themlen, infobuff, sizeof(infobuff)),
		themlen, strerror(errno));
	 return STAT_RETRYLATER;
      }

      Notice1("accepting UDP connection from %s",
	      sockaddr_info(&them->soa, themlen, infobuff, sizeof(infobuff)));

      if (xiocheckpeer(&fd->stream, them, la) < 0) {
	 /* drop packet */
	 char buff[512];
	 Recv(fd->stream.fd, buff, sizeof(buff), 0);	/* drop packet */
	 Close(fd->stream.fd);
	 continue;
      }
      Info1("permitting UDP connection from %s",
	    sockaddr_info(&them->soa, themlen, infobuff, sizeof(infobuff)));

      if (dofork) {
	 pid = xio_fork(false, E_ERROR);
	 if (pid < 0) {
	    return STAT_RETRYLATER;
	 }

	 if (pid == 0) {	/* child */
	    break;
	 }

	 /* server: continue loop with socket()+recvfrom() */
	 /* when we dont close this we get awkward behaviour on Linux 2.4:
	    recvfrom gives 0 bytes with invalid socket address */
	 if (Close(fd->stream.fd) < 0) {
	    Info2("close(%d): %s", fd->stream.fd, strerror(errno));
	 }
	 Sleep(1);	/*! give child a chance to consume the old packet */

	 continue;
      }
      break;
   }

   applyopts(fd->stream.fd, opts, PH_CONNECT);
   if ((result = Connect(fd->stream.fd, &them->soa, themlen)) < 0) {
      Error4("connect(%d, {%s}, "F_Zd"): %s",
	     fd->stream.fd,
	     sockaddr_info(&them->soa, themlen, infobuff, sizeof(infobuff)),
	     themlen, strerror(errno));
      return STAT_RETRYLATER;
   }

   /* set the env vars describing the local and remote sockets */
   if (Getsockname(fd->stream.fd, &us.soa, &uslen) < 0) {
      Warn4("getsockname(%d, %p, {%d}): %s",
	    fd->stream.fd, &us.soa, uslen, strerror(errno));
   }
   xiosetsockaddrenv("SOCK", &us,  uslen,   IPPROTO_UDP);
   xiosetsockaddrenv("PEER", them, themlen, IPPROTO_UDP);

   fd->stream.howtoend = END_SHUTDOWN;
   applyopts_fchown(fd->stream.fd, opts);
   applyopts(fd->stream.fd, opts, PH_LATE);

   if ((result = _xio_openlate(&fd->stream, opts)) < 0)
      return result;

   return 0;
}
예제 #2
0
파일: xio-listen.c 프로젝트: Averroes/socat
/* creates the listening socket, bind, applies options; waits for incoming
   connection, checks its source address and port. Depending on fork option, it
   may fork a subprocess.
   pf specifies the syntax expected for range option. In the case of generic
   socket it is 0 (expecting raw binary data), and the real pf can be obtained
   from us->af_family; for other socket types pf == us->af_family
   Returns 0 if a connection was accepted; with fork option, this is always in
   a subprocess!
   Other return values indicate a problem; this can happen in the master
   process or in a subprocess.
   This function does not retry. If you need retries, handle this in a
   loop in the calling function (and always provide the options...)
   After fork, we set the forever/retry of the child process to 0
   applies and consumes the following option:
   PH_INIT, PH_PASTSOCKET, PH_PREBIND, PH_BIND, PH_PASTBIND, PH_EARLY,
   PH_PREOPEN, PH_FD, PH_CONNECTED, PH_LATE, PH_LATE2
   OPT_FORK, OPT_SO_TYPE, OPT_SO_PROTOTYPE, OPT_BACKLOG, OPT_RANGE, tcpwrap,
   OPT_SOURCEPORT, OPT_LOWPORT, cloexec
 */
int _xioopen_listen(struct single *xfd, int xioflags, struct sockaddr *us, socklen_t uslen,
		 struct opt *opts, int pf, int socktype, int proto, int level) {
   struct sockaddr sa;
   socklen_t salen;
   int backlog = 5;	/* why? 1 seems to cause problems under some load */
   char *rangename;
   bool dofork = false;
   int maxchildren = 0;
   char infobuff[256];
   char lisname[256];
   union sockaddr_union _peername;
   union sockaddr_union _sockname;
   union sockaddr_union *pa = &_peername;	/* peer address */
   union sockaddr_union *la = &_sockname;	/* local address */
   socklen_t pas = sizeof(_peername);	/* peer address size */
   socklen_t las = sizeof(_sockname);	/* local address size */
   int result;

   retropt_bool(opts, OPT_FORK, &dofork);

   if (dofork) {
      if (!(xioflags & XIO_MAYFORK)) {
	 Error("option fork not allowed here");
	 return STAT_NORETRY;
      }
      xfd->flags |= XIO_DOESFORK;
   }

   retropt_int(opts, OPT_MAX_CHILDREN, &maxchildren);

   if (! dofork && maxchildren) {
       Error("option max-children not allowed without option fork");
       return STAT_NORETRY;
   }

   if (applyopts_single(xfd, opts, PH_INIT) < 0)  return -1;

   if (dofork) {
      xiosetchilddied();	/* set SIGCHLD handler */
   }

   if ((xfd->fd = xiosocket(opts, us->sa_family, socktype, proto, level)) < 0) {
      return STAT_RETRYLATER;
   }

   applyopts_cloexec(xfd->fd, opts);

   applyopts(xfd->fd, opts, PH_PREBIND);
   applyopts(xfd->fd, opts, PH_BIND);
   if (Bind(xfd->fd, (struct sockaddr *)us, uslen) < 0) {
      Msg4(level, "bind(%d, {%s}, "F_socklen"): %s", xfd->fd,
	   sockaddr_info(us, uslen, infobuff, sizeof(infobuff)), uslen,
	   strerror(errno));
      Close(xfd->fd);
      return STAT_RETRYLATER;
   }

#if WITH_UNIX
   if (us->sa_family == AF_UNIX) {
      applyopts_named(((struct sockaddr_un *)us)->sun_path, opts, PH_FD);
   }
#endif
   /* under some circumstances (e.g., TCP listen on port 0) bind() fills empty
      fields that we want to know. */
   salen = sizeof(sa);
   if (Getsockname(xfd->fd, us, &uslen) < 0) {
      Warn4("getsockname(%d, %p, {%d}): %s",
	    xfd->fd, &us, uslen, strerror(errno));
   }

   applyopts(xfd->fd, opts, PH_PASTBIND);
#if WITH_UNIX
   if (us->sa_family == AF_UNIX) {
      /*applyopts_early(((struct sockaddr_un *)us)->sun_path, opts);*/
      applyopts_named(((struct sockaddr_un *)us)->sun_path, opts, PH_EARLY);
      applyopts_named(((struct sockaddr_un *)us)->sun_path, opts, PH_PREOPEN);
   }
#endif /* WITH_UNIX */

#if WITH_IP4 /*|| WITH_IP6*/
   if (retropt_string(opts, OPT_RANGE, &rangename) >= 0) {
      if (xioparserange(rangename, pf, &xfd->para.socket.range)
	  < 0) {
	 free(rangename);
	 return STAT_NORETRY;
      }
      free(rangename);
      xfd->para.socket.dorange = true;
   }
#endif

#if (WITH_TCP || WITH_UDP) && WITH_LIBWRAP
   xio_retropt_tcpwrap(xfd, opts);
#endif /* && (WITH_TCP || WITH_UDP) && WITH_LIBWRAP */

#if WITH_TCP || WITH_UDP
   if (retropt_ushort(opts, OPT_SOURCEPORT, &xfd->para.socket.ip.sourceport) >= 0) {
      xfd->para.socket.ip.dosourceport = true;
   }
   retropt_bool(opts, OPT_LOWPORT, &xfd->para.socket.ip.lowport);
#endif /* WITH_TCP || WITH_UDP */

   applyopts(xfd->fd, opts, PH_PRELISTEN);
   retropt_int(opts, OPT_BACKLOG, &backlog);
   if (Listen(xfd->fd, backlog) < 0) {
      Error3("listen(%d, %d): %s", xfd->fd, backlog, strerror(errno));
      return STAT_RETRYLATER;
   }

   if (xioopts.logopt == 'm') {
      Info("starting accept loop, switching to syslog");
      diag_set('y', xioopts.syslogfac);  xioopts.logopt = 'y';
   } else {
      Info("starting accept loop");
   }
   while (true) {	/* but we only loop if fork option is set */
      char peername[256];
      char sockname[256];
      int ps;		/* peer socket */

      pa = &_peername;
      la = &_sockname;
      salen = sizeof(struct sockaddr);
      do {
	 /*? int level = E_ERROR;*/
	 Notice1("listening on %s", sockaddr_info(us, uslen, lisname, sizeof(lisname)));
	 ps = Accept(xfd->fd, (struct sockaddr *)&sa, &salen);
	 if (ps >= 0) {
	    /*0 Info4("accept(%d, %p, {"F_Zu"}) -> %d", xfd->fd, &sa, salen, ps);*/
	    break;	/* success, break out of loop */
	 }
	 if (errno == EINTR) {
	    continue;
	 }
	 if (errno == ECONNABORTED) {
	    Notice4("accept(%d, %p, {"F_socklen"}): %s",
		    xfd->fd, &sa, salen, strerror(errno));
	    continue;
	 }
	 Msg4(level, "accept(%d, %p, {"F_socklen"}): %s",
	      xfd->fd, &sa, salen, strerror(errno));
	 Close(xfd->fd);
	 return STAT_RETRYLATER;
      } while (true);
      applyopts_cloexec(ps, opts);
      if (Getpeername(ps, &pa->soa, &pas) < 0) {
	 Warn4("getpeername(%d, %p, {"F_socklen"}): %s",
	       ps, pa, pas, strerror(errno));
	 pa = NULL;
      }
      if (Getsockname(ps, &la->soa, &las) < 0) {
	 Warn4("getsockname(%d, %p, {"F_socklen"}): %s",
	       ps, la, las, strerror(errno));
	 la = NULL;
      }
      Notice2("accepting connection from %s on %s",
	      pa?
	      sockaddr_info(&pa->soa, pas, peername, sizeof(peername)):"NULL",
	      la?
	      sockaddr_info(&la->soa, las, sockname, sizeof(sockname)):"NULL");

      if (pa != NULL && la != NULL && xiocheckpeer(xfd, pa, la) < 0) {
	 if (Shutdown(ps, 2) < 0) {
	    Info2("shutdown(%d, 2): %s", ps, strerror(errno));
	 }
	 Close(ps);
	 continue;
      }

      if (pa != NULL)
	 Info1("permitting connection from %s",
	       sockaddr_info((struct sockaddr *)pa, pas,
			     infobuff, sizeof(infobuff)));

      if (dofork) {
	 pid_t pid;	/* mostly int; only used with fork */
         sigset_t mask_sigchld;

         /* we must prevent that the current packet triggers another fork;
            therefore we wait for a signal from the recent child: USR1
            indicates that is has consumed the last packet; CHLD means it has
            terminated */
         /* block SIGCHLD and SIGUSR1 until parent is ready to react */
         sigemptyset(&mask_sigchld);
         sigaddset(&mask_sigchld, SIGCHLD);
         Sigprocmask(SIG_BLOCK, &mask_sigchld, NULL);

	 if ((pid = xio_fork(false, level==E_ERROR?level:E_WARN)) < 0) {
	    Close(xfd->fd);
	    Sigprocmask(SIG_UNBLOCK, &mask_sigchld, NULL);
	    return STAT_RETRYLATER;
	 }
	 if (pid == 0) {	/* child */
	    pid_t cpid = Getpid();
	    Sigprocmask(SIG_UNBLOCK, &mask_sigchld, NULL);

	    Info1("just born: child process "F_pid, cpid);
	    xiosetenvulong("PID", cpid, 1);

	    if (Close(xfd->fd) < 0) {
	       Info2("close(%d): %s", xfd->fd, strerror(errno));
	    }
	    xfd->fd = ps;

#if WITH_RETRY
	    /* !? */
	    xfd->forever = false;  xfd->retry = 0;
	    level = E_ERROR;
#endif /* WITH_RETRY */

	    break;
	 }

	 /* server: continue loop with listen */
	 /* shutdown() closes the socket even for the child process, but
	    close() does what we want */
	 if (Close(ps) < 0) {
	    Info2("close(%d): %s", ps, strerror(errno));
	 }

         /* now we are ready to handle signals */
         Sigprocmask(SIG_UNBLOCK, &mask_sigchld, NULL);

	 while (maxchildren) {
	    if (num_child < maxchildren) break;
	    Notice("maxchildren are active, waiting");
	    /* UINT_MAX would even be nicer, but Openindiana works only
	       with 31 bits */
	    while (!Sleep(INT_MAX)) ;	/* any signal lets us continue */
	 }
	 Info("still listening");
      } else {
	 if (Close(xfd->fd) < 0) {
	    Info2("close(%d): %s", xfd->fd, strerror(errno));
	 }
	 xfd->fd = ps;
	break;
      }
   }

   applyopts(xfd->fd, opts, PH_FD);
   applyopts(xfd->fd, opts, PH_PASTSOCKET);
   applyopts(xfd->fd, opts, PH_CONNECTED);
   if ((result = _xio_openlate(xfd, opts)) < 0)
      return result;

   /* set the env vars describing the local and remote sockets */
   if (la != NULL)  xiosetsockaddrenv("SOCK", la, las, proto);
   if (pa != NULL)  xiosetsockaddrenv("PEER", pa, pas, proto);

   return 0;
}