484 lines
10 KiB
C
484 lines
10 KiB
C
/*
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* $Id$
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*
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* REPEATER.C
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*
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* CA broadcast repeater
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*
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* Author: Jeff Hill
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* Date: 3-27-90
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*
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* Control System Software for the GTA Project
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*
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* Copyright 1988, 1989, the Regents of the University of California.
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*
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* This software was produced under a U.S. Government contract
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* (W-7405-ENG-36) at the Los Alamos National Laboratory, which is
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* operated by the University of California for the U.S. Department
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* of Energy.
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*
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* Developed by the Controls and Automation Group (AT-8)
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* Accelerator Technology Division
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* Los Alamos National Laboratory
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*
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* Direct inqueries to:
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* Jeff HIll, AT-8, Mail Stop H820
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* Los Alamos National Laboratory
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* Los Alamos, New Mexico 87545
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* Phone: (505) 665-1831
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* E-mail: johill@lanl.gov
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*
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* PURPOSE:
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* Broadcasts fan out over the LAN, but UDP does not allow
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* two processes on the same machine to get the same broadcast.
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* This code extends the broadcast model from the net to within
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* the OS.
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*
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* NOTES:
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*
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* This server does not gaurantee the reliability of
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* fanned out broadcasts in keeping with the nature of
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* broadcasts. Therefore, CA retransmitts lost msgs.
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*
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* UDP datagrams delivered between two processes on the same
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* machine dont travel over the LAN.
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*
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*
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* Modification Log:
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* -----------------
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* .01 060691 joh Took out 4 byte count at message begin to
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* in preparation for SPARC alignment
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* .02 042892 joh No longer checking the status from free
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* since it varies from OS to OS
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* .03 042892 joh made local routines static
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* .04 072392 joh set reuse addr socket option so that
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* the repeater will restart if it gets killed
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* .05 072392 joh no longer needs to loop waiting for the timeout
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* to expire because of the change introduced
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* in .04
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* .06 120492 joh removed unnecessary includes
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* .07 120992 joh now uses dll list routines
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* .08 102993 joh toggle set sock opt to set
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* .09 070195 joh discover client has vanished by connecting its
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* datagram socket (and watching for ECONNREFUSED)
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*
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* $Log$
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* Revision 1.38 1996/11/02 00:51:04 jhill
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* many pc port, const in API, and other changes
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*
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* Revision 1.37 1996/09/04 20:02:32 jhill
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* fixed gcc warning
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*
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* Revision 1.36 1996/07/12 00:40:48 jhill
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* fixed client disconnect problem under solaris
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*
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* Revision 1.32.6.1 1996/07/12 00:39:59 jhill
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* fixed client disconnect problem under solaris
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*
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* Revision 1.35 1996/07/10 23:30:11 jhill
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* fixed GNU warnings
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*
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* Revision 1.34 1996/06/19 17:59:24 jhill
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* many 3.13 beta changes
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*
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* Revision 1.33 1995/11/29 19:19:05 jhill
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* Added $log$
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*
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*/
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static char *sccsId = "@(#)$Id$";
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#include "iocinf.h"
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/*
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* one socket per client so we will get the ECONNREFUSED
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* error code (and then delete the client)
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*/
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struct one_client{
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ELLNODE node;
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struct sockaddr_in from;
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SOCKET sock;
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};
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/*
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* these can be external since there is only one instance
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* per machine so we dont care about reentrancy
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*/
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static ELLLIST client_list;
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static char buf[MAX_UDP];
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LOCAL void register_new_client(struct sockaddr_in *pLocal,
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struct sockaddr_in *pFrom);
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LOCAL void verifyClients();
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#define PORT_ANY 0U
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LOCAL SOCKET makeSocket(unsigned short port, int reuseAddr);
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LOCAL void fanOut(struct sockaddr_in *pFrom, const char *pMsg, unsigned msgSize);
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/*
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*
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* ca_repeater()
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*
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*
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*/
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void ca_repeater()
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{
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int status;
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int size;
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SOCKET sock;
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struct sockaddr_in from;
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struct sockaddr_in local;
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int from_size = sizeof from;
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unsigned short port;
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port = caFetchPortConfig(
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&EPICS_CA_REPEATER_PORT,
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CA_REPEATER_PORT);
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ellInit(&client_list);
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sock = makeSocket(port, TRUE);
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if (sock==INVALID_SOCKET) {
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/*
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* test for server was already started
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*/
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if (SOCKERRNO==EADDRINUSE) {
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exit(0);
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}
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ca_printf("%s: Unable to create repeater socket because \"%s\"\n",
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__FILE__,
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strerror(SOCKERRNO));
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exit(0);
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}
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status = local_addr(sock, &local);
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if(status != OK){
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ca_printf(
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"CA Repeater: failed during initialization - no local IP address\n");
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exit (0);
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}
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#ifdef DEBUG
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ca_printf("CA Repeater: Attached and initialized\n");
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#endif
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while(TRUE){
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caHdr *pMsg;
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size = recvfrom(
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sock,
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buf,
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sizeof(buf),
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0,
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(struct sockaddr *)&from,
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&from_size);
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if(size < 0){
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# ifdef linux
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/*
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* Avoid spurious ECONNREFUSED bug
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* in linux
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*/
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if (SOCKERRNO==ECONNREFUSED) {
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continue;
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}
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# endif
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ca_printf("CA Repeater: recv err %s\n",
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strerror(SOCKERRNO));
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continue;
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}
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pMsg = (caHdr *) buf;
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/*
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* both zero length message and a registration message
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* will register a new client
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*/
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if( ((size_t)size) >= sizeof(*pMsg)){
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if(ntohs(pMsg->m_cmmd) == REPEATER_REGISTER){
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register_new_client(&local, &from);
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/*
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* strip register client message
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*/
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pMsg++;
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size -= sizeof(*pMsg);
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if (size==0) {
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continue;
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}
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}
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}
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else if(size == 0){
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register_new_client(&local, &from);
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continue;
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}
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fanOut(&from, (char *) pMsg, size);
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}
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}
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/*
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* fanOut()
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*/
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LOCAL void fanOut(struct sockaddr_in *pFrom, const char *pMsg, unsigned msgSize)
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{
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ELLLIST theClients;
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struct one_client *pclient;
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int status;
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ellInit(&theClients);
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while ( (pclient=(struct one_client *)ellGet(&client_list)) ) {
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ellAdd(&theClients, &pclient->node);
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/*
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* Dont reflect back to sender
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*/
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if(pFrom->sin_port == pclient->from.sin_port &&
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pFrom->sin_addr.s_addr == pclient->from.sin_addr.s_addr){
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continue;
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}
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status = send(
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pclient->sock,
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(char *)pMsg,
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msgSize,
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0);
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if (status>=0) {
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#ifdef DEBUG
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ca_printf("Sent to %d\n",
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pclient->from.sin_port);
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#endif
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}
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if(status < 0){
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if (SOCKERRNO == ECONNREFUSED) {
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#ifdef DEBUG
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ca_printf("Deleted client %d\n",
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ntohs( pclient->from.sin_port));
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#endif
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ellDelete(&theClients,
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&pclient->node);
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socket_close(pclient->sock);
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free(pclient);
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}
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else {
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ca_printf(
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"CA Repeater: fan out err was \"%s\"\n",
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strerror(SOCKERRNO));
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}
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}
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}
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ellConcat(&client_list, &theClients);
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}
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/*
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* verifyClients()
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* (this is required because solaris has a half baked version of sockets)
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*/
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LOCAL void verifyClients()
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{
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ELLLIST theClients;
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SOCKET sock;
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struct one_client *pclient;
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ellInit(&theClients);
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while ( (pclient=(struct one_client *)ellGet(&client_list)) ) {
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ellAdd(&theClients, &pclient->node);
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sock = makeSocket(ntohs(pclient->from.sin_port), FALSE);
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if (sock!=INVALID_SOCKET) {
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#ifdef DEBUG
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ca_printf("Deleted client %d\n",
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ntohs(pclient->from.sin_port));
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#endif
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ellDelete(&theClients, &pclient->node);
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socket_close(sock);
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socket_close(pclient->sock);
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free(pclient);
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}
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else {
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if (SOCKERRNO!=EADDRINUSE) {
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ca_printf(
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"CA Repeater: bind test err was %d=\"%s\"\n",
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SOCKERRNO, strerror(SOCKERRNO));
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}
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}
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}
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ellConcat(&client_list, &theClients);
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}
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/*
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* makeSocket()
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*/
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LOCAL SOCKET makeSocket(unsigned short port, int reuseAddr)
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{
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int status;
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struct sockaddr_in bd;
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SOCKET sock;
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int true = 1;
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sock = socket( AF_INET, /* domain */
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SOCK_DGRAM, /* type */
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0); /* deflt proto */
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if (sock == INVALID_SOCKET) {
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return sock;
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}
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/*
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* no need to bind if unconstrained
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*/
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if (port != PORT_ANY) {
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memset((char *)&bd, 0, sizeof(bd));
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bd.sin_family = AF_INET;
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bd.sin_addr.s_addr = INADDR_ANY;
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bd.sin_port = htons(port);
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status = bind(sock, (struct sockaddr *)&bd, (int)sizeof(bd));
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if (status<0) {
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socket_close(sock);
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return INVALID_SOCKET;
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}
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if (reuseAddr) {
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status = setsockopt( sock,
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SOL_SOCKET,
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SO_REUSEADDR,
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(char *)&true,
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sizeof(true));
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if (status<0) {
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ca_printf(
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"%s: set socket option failed because \"%s\"\n",
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__FILE__, strerror(SOCKERRNO));
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}
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}
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}
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return sock;
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}
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/*
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* register_new_client()
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*/
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LOCAL void register_new_client(
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struct sockaddr_in *pLocal,
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struct sockaddr_in *pFrom)
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{
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int status;
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struct one_client *pclient;
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caHdr confirm;
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caHdr noop;
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int newClient = FALSE;
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if (pFrom->sin_family != AF_INET) {
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return;
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}
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/*
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* the repeater and its clients must be on the same host
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*/
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if (pLocal->sin_addr.s_addr != pFrom->sin_addr.s_addr) {
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return;
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}
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for( pclient = (struct one_client *) ellFirst(&client_list);
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pclient;
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pclient = (struct one_client *) ellNext(&pclient->node)){
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if (pFrom->sin_port == pclient->from.sin_port) {
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break;
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}
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}
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if (!pclient) {
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pclient = (struct one_client *)calloc (1, sizeof(*pclient));
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if (!pclient) {
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ca_printf("%s: no memory for new client\n",
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__FILE__);
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return;
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}
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pclient->sock = makeSocket(PORT_ANY, FALSE);
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if (pclient->sock==INVALID_SOCKET) {
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free(pclient);
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ca_printf("%s: no client sock because \"%s\"\n",
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__FILE__,
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strerror(SOCKERRNO));
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return;
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}
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status = connect(pclient->sock,
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(struct sockaddr *)pFrom,
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sizeof(*pFrom));
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if (status<0) {
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socket_close(pclient->sock);
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free(pclient);
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ca_printf(
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"%s: unable to connect client sock because \"%s\"\n",
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__FILE__, strerror(errno));
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return;
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}
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pclient->from = *pFrom;
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ellAdd (&client_list, &pclient->node);
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newClient = TRUE;
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#ifdef DEBUG
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ca_printf (
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"Added %d\n",
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ntohs(pFrom->sin_port));
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#endif
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}
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memset((char *)&confirm, '\0', sizeof(confirm));
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confirm.m_cmmd = htons(REPEATER_CONFIRM);
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confirm.m_available = pLocal->sin_addr.s_addr;
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status = send(
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pclient->sock,
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(char *)&confirm,
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sizeof(confirm),
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0);
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if (status >= 0) {
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assert(status == sizeof(confirm));
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}
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else if (SOCKERRNO == ECONNREFUSED){
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#ifdef DEBUG
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ca_printf("Deleted repeater client=%d sending ack\n",
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pFrom->sin_port);
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#endif
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ellDelete(&client_list, &pclient->node);
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socket_close(pclient->sock);
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free(pclient);
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}
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else {
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ca_printf("CA Repeater: confirm err was \"%s\"\n",
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strerror(SOCKERRNO));
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}
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/*
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* send a noop message to all other clients so that we dont
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* accumulate sockets when there are no beacons
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*/
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memset((char *)&noop, '\0', sizeof(noop));
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confirm.m_cmmd = htons(CA_PROTO_NOOP);
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fanOut(pFrom, (char *)&noop, sizeof(noop));
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if (newClient) {
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/*
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* on solaris we need to verify that the clients
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* have not gone away (because ICMP does not
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* get through to send()
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*
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* this is done each time that a new client is
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* created
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*
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* this is done here in order to avoid deleting
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* a client prior to sending its confirm message
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*/
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verifyClients();
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}
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}
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