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net-ip.cc

/*-
 * Copyright (c) 1993-1994 The Regents of the University of California.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *      This product includes software developed by the University of
 *      California, Berkeley and the Network Research Group at
 *      Lawrence Berkeley Laboratory.
 * 4. Neither the name of the University nor of the Laboratory may be used
 *    to endorse or promote products derived from this software without
 *    specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */
static const char rcsid[] =
    "@(#) $Header: net-ip.cc,v 1.3 96/05/16 05:27:43 van Exp $ (LBL)";

#include <stdio.h>
#include <errno.h>
#include <string.h>
#ifdef WIN32
#include <io.h>
#define close closesocket
#else
#include <sys/param.h>
#include <sys/socket.h>
#include <sys/ioctl.h>
#endif
#if defined(sun) && defined(__svr4__)
#include <sys/systeminfo.h>
#endif

#include "config.h"
#include "net.h"
#include "Tcl.h"

class IPNetwork : public Network {
    public:
      virtual int command(int argc, const char*const* argv);
      virtual void reset();
    protected:
      int open(u_int32_t addr, int port, int ttl);
      int close();
      void localname(sockaddr_in*);
      int openssock(u_int32_t addr, u_short port, int ttl);
      int openrsock(u_int32_t addr, u_short port,
                  const struct sockaddr_in& local);
      time_t last_reset_;
};

static class IPNetworkMatcher : public Matcher {
    public:
      IPNetworkMatcher() : Matcher("network") {}
      TclObject* match(const char* id) {
            if (strcasecmp(id, "ip") == 0)
                  return (new IPNetwork);
            else
                  return (0);
      }
} nm_ip;

int IPNetwork::command(int argc, const char*const* argv)
{
      Tcl& tcl = Tcl::instance();
      if (argc == 2) {
            if (strcmp(argv[1], "close") == 0) {
                  close();
                  return (TCL_OK);
            }
            char* cp = tcl.result();
            if (strcmp(argv[1], "addr") == 0) {
                  strcpy(cp, intoa(addr_));
                  return (TCL_OK);
            }
            if (strcmp(argv[1], "interface") == 0) {
                  strcpy(cp, intoa(local_));
                  return (TCL_OK);
            }
            if (strcmp(argv[1], "port") == 0) {
                  sprintf(cp, "%d", ntohs(port_));
                  return (TCL_OK);
            }
            if (strcmp(argv[1], "localport") == 0) {
                  sprintf(cp, "%d", ntohs(lport_));
                  return (TCL_OK);
            }
            if (strcmp(argv[1], "ttl") == 0) {
                  sprintf(cp, "%d", ttl_);
                  return (TCL_OK);
            }
            if (strcmp(argv[1], "ismulticast") == 0) {
                  tcl.result(IN_CLASSD(ntohl(addr_))? "1" : "0");
                  return (TCL_OK);
            }
      } else if (argc == 3) {
            if (strcmp(argv[1], "loopback") == 0) {
                  char c = atoi(argv[2]);
                  if (setsockopt(ssock_, IPPROTO_IP, IP_MULTICAST_LOOP,
                               &c, 1) < 0) {
                        /*
                         * If we cannot turn off loopback (Like on the
                         * Microsoft TCP/IP stack), then declare this
                         * option broken so that our packets can be
                         * filtered on the recv path.
                         */
                        if (c == 0)
                              noloopback_broken_ = 1;
                  }
                  return (TCL_OK);
            }
      } else if (argc == 5) {
            if (strcmp(argv[1], "open") == 0) {
                  u_int32_t addr = LookupHostAddr(argv[2]);
                  int port = htons(atoi(argv[3]));
                  int ttl = atoi(argv[4]);
                  if (open(addr, port, ttl) < 0)
                        tcl.result("0");
                  else
                        tcl.result("1");
                  return (TCL_OK);
            }
      }
      return (Network::command(argc, argv));
}

int IPNetwork::open(u_int32_t addr, int port, int ttl)
{
      addr_ = addr;
      port_ = port;
      ttl_ = ttl;

      ssock_ = openssock(addr, port, ttl);
      if (ssock_ < 0)
            return (-1);
      /*
       * Connecting the send socket also bound the local address.
       * On a multihomed host we need to bind the receive socket
       * to the same local address the kernel has chosen to send on.
       */
      sockaddr_in local;
      localname(&local);
      rsock_ = openrsock(addr, port, local);
      if (rsock_ < 0) {
            (void)::close(ssock_);
            return (-1);
      }
      local_ = local.sin_addr.s_addr;
#if defined(sun) && defined(__svr4__)
      /*
       * gethostname on solaris prior to 2.6 always returns 0 for
       * udp sockets.  do a horrible kluge that often fails on
       * multihomed hosts to get the local address (we don't use
       * this to open the recv sock, only for the 'interface'
       * tcl command).
       */
      if (local_ == 0) {
            char myhostname[1024];
            int error;

            error = sysinfo(SI_HOSTNAME, myhostname, sizeof(myhostname));
            if (error == -1) {
                  perror("Getting my hostname");
                  exit(-1);
            }
            local_ = LookupHostAddr(myhostname);
      }
#endif
      lport_ = local.sin_port;
      last_reset_ = 0;
      return (0);
}

int IPNetwork::close()
{
      if (ssock_ >= 0) {
            ::close(ssock_);
            ::close(rsock_);
            ssock_ = rsock_ = -1;
      }
      return (0);
}

void IPNetwork::localname(sockaddr_in* p)
{
      memset((char *)p, 0, sizeof(*p));
      p->sin_family = AF_INET;
      int len = sizeof(*p);
      if (getsockname(ssock_, (struct sockaddr *)p, &len) < 0) {
            perror("getsockname");
            p->sin_addr.s_addr = 0;
            p->sin_port = 0;
      }
#ifdef WIN32
      if (p->sin_addr.s_addr == 0) {
            char hostname[80];
            struct hostent *hp;

            if (gethostname(hostname, sizeof(hostname)) >= 0) {
                  if ((hp = gethostbyname(hostname)) >= 0) {
                        p->sin_addr.s_addr = ((struct in_addr *)hp->h_addr)->s_addr;
                  }
            }
      }
#endif      
}

void IPNetwork::reset()
{
      time_t t = time(0);
      int d = int(t - last_reset_);
      if (d > 3) {
            last_reset_ = t;
            (void)::close(ssock_);
            ssock_ = openssock(addr_, port_, ttl_);
      }
}

int IPNetwork::openrsock(u_int32_t addr, u_short port,
                      const struct sockaddr_in& local)
{
      int fd;
      struct sockaddr_in sin;

      fd = socket(AF_INET, SOCK_DGRAM, 0);
      if (fd < 0) {
            perror("socket");
            exit(1);
      }
      nonblock(fd);
      int on = 1;
      if (setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, (char *)&on,
                  sizeof(on)) < 0) {
            perror("SO_REUSEADDR");
      }
#ifdef SO_REUSEPORT
      on = 1;
      if (setsockopt(fd, SOL_SOCKET, SO_REUSEPORT, (char *)&on,
                   sizeof(on)) < 0) {
            perror("SO_REUSEPORT");
            exit(1);
      }
#endif
      memset((char *)&sin, 0, sizeof(sin));
      sin.sin_family = AF_INET;
      sin.sin_port = port;
#ifdef IP_ADD_MEMBERSHIP
      if (IN_CLASSD(ntohl(addr))) {
            /*
             * Try to bind the multicast address as the socket
             * dest address.  On many systems this won't work
             * so fall back to a destination of INADDR_ANY if
             * the first bind fails.
             */
            sin.sin_addr.s_addr = addr;
            if (bind(fd, (struct sockaddr *)&sin, sizeof(sin)) < 0) {
                  sin.sin_addr.s_addr = INADDR_ANY;
                  if (bind(fd, (struct sockaddr*)&sin, sizeof(sin)) < 0) {
                        perror("bind");
                        exit(1);
                  }
            }
            /* 
             * XXX This is bogus multicast setup that really
             * shouldn't have to be done (group membership should be
             * implicit in the IP class D address, route should contain
             * ttl & no loopback flag, etc.).  Steve Deering has promised
             * to fix this for the 4.4bsd release.  We're all waiting
             * with bated breath.
             */
            struct ip_mreq mr;

            mr.imr_multiaddr.s_addr = addr;
            mr.imr_interface.s_addr = INADDR_ANY;
            if (setsockopt(fd, IPPROTO_IP, IP_ADD_MEMBERSHIP, 
                         (char *)&mr, sizeof(mr)) < 0) {
                  perror("IP_ADD_MEMBERSHIP");
                  exit(1);
            }
      } else
#endif
      {
            /*
             * bind the local host's address to this socket.  If that
             * fails, another vic probably has the addresses bound so
             * just exit.
             */
            sin.sin_addr.s_addr = local.sin_addr.s_addr;
            if (bind(fd, (struct sockaddr *)&sin, sizeof(sin)) < 0) {
                  perror("bind");
                  exit(1);
            }
            /*
             * Despite several attempts on our part to get this fixed,
             * Microsoft Windows isn't complient with the Internet Host
             * Requirements standard (RFC-1122) and won't let us include
             * the source address in the receive socket demux state.
             * (The consequence of this is that all conversations have
             * to be assigned a unique local port so the vat 'side
             * conversation' (middle click on site name) function is
             * essentially useless under windows.)
             */
#ifndef WIN32
            /*
             * (try to) connect the foreign host's address to this socket.
             */
            sin.sin_port = 0;
            sin.sin_addr.s_addr = addr;
            connect(fd, (struct sockaddr *)&sin, sizeof(sin));
#endif
      }
      /*
       * XXX don't need this for the session socket.
       */   
      int bufsize = 80 * 1024;
      if (setsockopt(fd, SOL_SOCKET, SO_RCVBUF, (char *)&bufsize,
                  sizeof(bufsize)) < 0) {
            bufsize = 32 * 1024;
            if (setsockopt(fd, SOL_SOCKET, SO_RCVBUF, (char *)&bufsize,
                        sizeof(bufsize)) < 0)
                  perror("SO_RCVBUF");
      }
      return (fd);
}

int IPNetwork::openssock(u_int32_t addr, u_short port, int ttl)
{
      int fd;
      struct sockaddr_in sin;

      fd = socket(AF_INET, SOCK_DGRAM, 0);
      if (fd < 0) {
            perror("socket");
            exit(1);
      }
      nonblock(fd);

#ifdef WIN32
      memset((char *)&sin, 0, sizeof(sin));
      sin.sin_family = AF_INET;
      sin.sin_port = 0;
      sin.sin_addr.s_addr = INADDR_ANY;
      if (bind(fd, (struct sockaddr *)&sin, sizeof(sin)) < 0) {
            perror("bind");
            exit(1);
      }
#endif
      memset((char *)&sin, 0, sizeof(sin));
      sin.sin_family = AF_INET;
      sin.sin_port = port;
      sin.sin_addr.s_addr = addr;
      if (connect(fd, (struct sockaddr *)&sin, sizeof(sin)) < 0) {
            perror("connect");
            exit(1);
      }
      if (IN_CLASSD(ntohl(addr))) {
#ifdef IP_ADD_MEMBERSHIP
            char c;

            /* turn off loopback */
            c = 0;
            if (setsockopt(fd, IPPROTO_IP, IP_MULTICAST_LOOP, &c, 1) < 0) {
                  /*
                   * If we cannot turn off loopback (Like on the
                   * Microsoft TCP/IP stack), then declare this
                   * option broken so that our packets can be
                   * filtered on the recv path.
                   */
                  if (c == 0)
                        noloopback_broken_ = 1;
            }
            /* set the multicast TTL */
#ifdef WIN32
            u_int t;
#else
            u_char t;
#endif
            t = (ttl > 255) ? 255 : (ttl < 0) ? 0 : ttl;
            if (setsockopt(fd, IPPROTO_IP, IP_MULTICAST_TTL,
                         (char*)&t, sizeof(t)) < 0) {
                  perror("IP_MULTICAST_TTL");
                  exit(1);
            }
#else
            fprintf(stderr, "\
not compiled with support for IP multicast\n\
you must specify a unicast destination\n");
            exit(1);
#endif
      }
      /*
       * XXX don't need this for the session socket.
       */
      int bufsize = 80 * 1024;
      if (setsockopt(fd, SOL_SOCKET, SO_SNDBUF, (char *)&bufsize,
                   sizeof(bufsize)) < 0) {
            bufsize = 48 * 1024;
            if (setsockopt(fd, SOL_SOCKET, SO_SNDBUF, (char *)&bufsize,
                         sizeof(bufsize)) < 0)
                  perror("SO_SNDBUF");
      }
      return (fd);
}


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