/* voevent_client_demo.c -- to demonstrate a VOEvent socket connection to GCN/TAN * * USAGE: * voevent_client_demo * * Where "ip_adress" is the ip address of the GCN/VOEvent server. * Where "port_num" is the port number of the GCN/VOEvent server. * * Example: voevent_client_demo 209.208.78.170 8099 * * DESCRIPTION: * INTRO: This standalone C program shows all the neccessary parts * that a site would use to become a GCN/TAN site connected via * the IVOA VOEvent socket method. With this program you can connect * to the GCN/TAN system of VOEvent servers and receive VOEvents. * The parts of this program can be cut and spliced into your * site's instrument-control software, or this program can be used * as the basis of your instrument's control program (there is a place * noted in the code where to put your instrument-specific code), * or you can use it to just receive the VOEvents. * * CLIENT-SERVER: The site (ie your end of the socket connection) * is "client" end. The "server" end (ie the VOEvent server) is running on * one of the GCN/TAN machines. There are currently 3 servers: * 209.208.78.170 (on Atlantic.net cloud service) * 50.116.49.68 (on Linode.com cloud service) * 68.169.57.253 (on eApps.com cloud service) * All the GCN/TAN VOEvent servers are listening on port 8099. * You, the client, initiate a connection to the server. * The client-server uses the TCP/IP socket method with the protocol * described in http://www.ivoa.net/Documents/Notes/VOEventTransport/ . * * PACKET TYPES: This program handles all the types of VOEvent Notices * that the GCN/TAN system produces directly and redistributes from other servers. * * FILTERING: There are two modes to receive these VOEvents. * 1) A site can register with GCN/TAN and set up a "configuration". * The configuration contains which Notice types you want to receive and * what other filtering functions to be applied (exactly like the original * GCN filtering functionality, in fact, it is the same "sites.cfg" file). * 2) A site can connect (without registering) anonymously. As such, * no filtering can be applied (since there is no pre-arranged configuration), * and you will receive everything that GCN/TAN produces (as of Feb 2012, * this is about 2000 VOEvents per day). * * SERVER DUPLICATION: All 3 GCN/TAN servers listed above (and any others * that might be brought on-line in the future) have identical streams of VOEvents. * So connecting to any single server will provide you with the 100% full content * that GCN/TAN produces. And since all 3 servers use identical "sites.cfg" files, * registered users can switch from one server to another without any * further effort needed on their part. * * SUBSCRIBING/PUBLISHING: This voevent_client_demo program implements * the basic subscriber service. It does not implement the publisher function. * However, the GCN/TAN server/broker program does except publications from subscribers. * If a registered subscriber writes a VOEvent back to GCN/TAN (on port 8098), * it will be accepted and distributed to the other client/subscribers * connected at the time. Publications from anonymous clients/subscribers * will not be accepted. * * SPEED: The VOEvent socket distribution method is very fast. It takes * 3-10 milliseconds to get the packet from the GCN/TAN voevent server computer * to your computer. * * ACK/NACK: For each VOEvent message the client receives, the client should * send back an "ack" or "nack". An ack if the message is complete and valid, * or a nack if not complete or does not validate. (This demo client does not * implement validation, so only "acks" are sent back to the server * for everything received.) * * ALIVENESS CHECKING: This program tests to see if it has received anything * in the last 200 sec (since imalives come every 60 sec). * If nothing was received within the last 200 sec, it breaks the connection and * automatically tries to reconnect to the server. * * DOES NOT DO: This demo client program does not implement the following functions: * a) Validating the XML VOEvent messages, * b) Parsing the XML VOEvent messages, * c) Authentication of the sender (GCN/TAN in this case), * d) Publishing your own VOEvents back to GCN/TAN server/broker. * * OPERATIONAL CONSIDERATIONS: * ONLY ONE PROGRAM AT A TIME ON ONE COMPUTER: If you choose to connect * to GCN/TAN as a vetted site, you can only have one client running * on the registered machine per server. A second connection will esentially * overwrite/replace the first connection. GCN/TAN recognizes incoming connections * by their IP Number. So two clients with the same IP Number (ie same computer) * will be recognized by both entries in the sites configuration file. * The first client will get nothing, because its connection will be * overwritten/replaced by the second). And if there is only one entry * in the config file that has your computer's IP Number, then the second * connection will again overwrite the first connection, and only the second * will get events. If you need two clients on one machine, then have the * second connection connect to one of the other GCN/TAN servers. Each client * will get the one config's set of VOEvents. * Anonymous sites can have multiple clients running on the same machine; * they will each receive all the VOEvents produced by GCN/TAN. * * STANDARDOUT COPY: This program duplicates almost all of its output * to the logfile also to the standardout. This duplication to the stdout * allows the first-time/interactive user to "see" what is going on with the * operations of the program. After a while, you will probably want to * (a) invoke the program with the stdout redirected to /dev/null and * run it in the background: * voevent_client_demo ip_addr portnum >& /dev/null & * or (b) start commenting-out some of the stdout printf's that you no longer * want to see. * * ERRORS: All the "bad situations" within the operations of this demo program * are marked in the print statements with the prefix "ERR:" to the error message. * This prefix allows the user to quickly search the logfile for instances of bad activity. * * FILES: * ./voevent_client_demo.log // A logfile of all packets received and program actions & errors. * * LIST OF ROUTINES: * main() // The main processing routine * brokenpipe() // Wrap things up if the socket connection breaks * establish_server_conn() // Establish a connection to the server * burn_off() // Burn off the stuff in the input read buffer * fixedgmtime() // Fixed GMTime() wrapper (ie convert a year_value of 112 --> 12) * ut_ctime() // Convert TimeStruct into yy/mm/dd hh:mm:ss string * build_imalive_response() // Build an Imalive Response Message to receiving an imalive message * build_voevent_response() // Build an VOEvent Response Message to receiving a voevent message * extract_ivorn() // Extract Ivorn from voevent message * * CHANGE BEFORE COMPILE: * There are 4 program variables which must be given values specific to your site's setup * before compiling. See lines ~186 thru ~191. * * COMPILATION: * For LINUX platforms: * cc voevent_client_demo.c -o voevent_client_demo * (If you run on a 64-bit platform, you may need to add a -m32 to your compile options.) * * MISC NOTES: * 1) This file looks best with a tabstop=4 setting. * * 2) This code was purposefully written in a simple brute-force style * so that it is easier to read no matter what the experience level of the end-user. * Also, by not using the full set of features within the C-language, * it is easier to transliterate to other languages (eg Python, Fortran, whatever). * It is all in a single file to make public distribution and installation easier. * * SEE ALSO: * xml_socket_demo.c // The VOEvent XML messages, but uses the GCN protocol * socket_demo.c // The original 160-byte binary GCN packet protocol * * AUTHOR: * Scott Barthelmy NASA-GSFC Code 661.0 * Teresa Sheets NASA-GSFC Code 587.0 */ // Please note that most of these include_files are the ones for LINUX. // On other machines with different operating systems (or even different // versions of unix), these include_files may have different names. // If, when you compile voevent_client_demo.c on your local platform, you find // that one or more of these files are "not found", then you will have // to explore your system's include_files to find the contents that are missing // during the compilation process. Unfortunately, there are too many // combinations of op_sys's for me to incorporate the appropriate include_files. #include // Standard i/o header file #include // For the brokenpipe signal catching #include // For strcpy(), strcat(), etc #include // For the ioctl() call to make the connection non-blocking #include // For read(), sync(), close(), ... #include // For the time() and ut_ctime() calls #include // For the error handling #include // For the system() and exit() calls #include // For the socket structures and calls #define TRUE 1 // Common sense logic macros #define FALSE 0 #define BUF_SZ 30000 // Size of the xml read-in buffer char *version = "voevent_client_demo Ver: 1.00 02 Mar 2012"; // ************************************************************************************** // THESE NEXT 4 ITEMS NEED TO BE ASSIGNED VALUES APPROPRIATE TO THE LOCAL USER: char ack_subivo[100] = "ivo://voevent_subscriber_name#"; // The ivorn of the subscriber (something that IDs you) char ack_ipaddr[50] = "\"subscibers_ip_addr:123.123.123.123\""; // Your IP number where this client is running char ack_contact[100] = "\"yourname@your.email.address\""; // Your contact email address // The ack_result_mesg may be filled with whatever message you would like to send back to the server. // You could modify this code to create a different response for different (good vs bad) conditions. char ack_result_mesg[100] = "Message received."; // Whatever response information you want to send back // ************************************************************************************** // A few global variables for the voevent_client_demo program: FILE *lg; // Logfile stream pointer int errno; // Error return code number time_t tloc; // Seconds since machine epoch char on = 1; // Used to allow re-connects before FIN_WAIT clears struct sockaddr_in serv_addr; // Structure of server info int ssd; // Server Socket Descriptor // Declarations of functions used in the program: void brokenpipe(); // Clean up after getting a brokenpipe signal void establish_server_conn(); // Establish a connection to the server void burn_off(); // Burn off the input read buffer, try to get back in sync char *ut_ctime(struct tm *); // Convert TimeStruct into yy/mm/dd hh:mm:ss string char *build_voevent_response(); // Build client specific VOEvent Message Response char *build_iamalive_response(); // Build client specific Iamalive Response char *extract_ivorn(char *); // Extract ivorn from buffer /*---------------------------------------------------------------------------*/ int main(argc, argv) int argc; // Number of cmdline arguments char *argv[]; // Pointers to all the cmdline arguments { int bytes1,bytes2,bytes3;// Number of bytes read from the socket int wbytes1,wbytes2; // Number of bytes written to the socket int got_voe=0; // Flag indicating received a VO message (imalive or VOEvent) long pktlen; // Number of bytes to read from or write to the socket (a 4-byte long) long netpktlen; // Network byte order number of bytes read from or written to the socket char xmlbuf[BUF_SZ]; // The packet data buffer struct sigvec vec; // Signal vector structure time_t nowtime; // The current system time time_t last_nowtime; // The time of the last packet received struct tm *tim, *fixedgmtime();// Ptr to struct of date/time stuff char *ackbuf; // Pointer to the regular response (from build_voevent_response()) char *ackima; // Pointer to the imalive response (from build_iamalive_response()) char *p; // Pointer to printf() format string to build print messages if(argc != 3) { printf("USAGE: voevent_client_demo \n"); exit(1); } bzero((char *)xmlbuf,sizeof(xmlbuf)); // Clears the buffer time(&last_nowtime); // Init this so it doesn't trip on the first loop tim = fixedgmtime(&nowtime); // Fill up the structure // Open the logfile: if((lg = fopen("voevent_client_demo.log", "a")) == NULL) // Open for appending { printf("Failed to open logfile. Exiting.\n"); exit(2); } // Write the banner and timestamp to the logfile: fprintf(lg,"\n===================== New Session ========================\n"); fprintf(lg,"Start Time: %s Program: %s\n",ut_ctime(tim),version); fprintf(lg,"host_ip=%s, port=%d\n",argv[1],atoi(argv[2])); // Set up the signal catcher (so brokenpipe() is called when a socket broken): vec.sv_handler = brokenpipe; vec.sv_mask = sigmask(SIGPIPE); vec.sv_flags = 0; if(sigvec(SIGPIPE, &vec, (struct sigvec *) NULL) == -1) { printf( "ERR: Sigvec() did not work when setting up brokenpipe.\n"); fprintf(lg,"ERR: Sigvec() did not work when setting up brokenpipe.\n"); } // Set up the client connection to the server: bzero((char *) &serv_addr, sizeof(serv_addr)); // Be sure to start out with a clean structure (paranoid) serv_addr.sin_family = AF_INET; // This will be an internet connection serv_addr.sin_addr.s_addr = inet_addr(argv[1]); // The server's name (1st arg on the cmdline) serv_addr.sin_port = htons(atoi(argv[2])); // Port number on the server (converted to network byte order) establish_server_conn(); // Establish a connection to the server // An infinite loop for reading the socket (the voevents & the imalives), // and handling the reconnection if there is a break. // Also, near the end of this loop is your site/instrument-specific code (if you want). while(1) { if(ssd <= 0) printf("Not Connected...\n"); // A busy light else printf("Checking for data. (or Possibly checking for connection.)\n"); time(&nowtime); // Get the current system time tim = fixedgmtime(&nowtime); // Fill up the structure got_voe = 0; // Initialize the got-something flag // If socket is connected, read the socket for any xml_message; // if the socket does not have a message, continue to loop. if(ssd <= 0) // Not connected { // If the sock descriptor is zero or less, the socket connection has been broken. // Try to re-establish the socket. printf( "%s Detected disconnect. Attempting to reconnect.\n",ut_ctime(tim)); fprintf(lg,"%s Detected disconnect. Attempting to reconnect.\n",ut_ctime(tim)); establish_server_conn(); // Re-establish a connection to the server } else // Connected { // Two read() calls to rcv: (1) a 4-byte length, (2) then the xml message. if((bytes1=read(ssd,(char *)&netpktlen,sizeof(netpktlen))) > 0) { pktlen = ntohl(netpktlen); // Convert it from network byte order to local host byte order printf("%s 1st read: bytes=%d, pktlen=%ld=0x%lX netpktlen=%ld=0x%lX, errno=%d=%s.\n", ut_ctime(tim),bytes1, pktlen,(unsigned long)pktlen, netpktlen,(unsigned long)netpktlen, errno, strerror(errno)); if((pktlen < 0) || (pktlen > BUF_SZ)) { printf( "ERR: Pktlen(=%ld) was out of range (<0 or >%d); we must be out of sync.\n",pktlen,BUF_SZ); fprintf(lg,"ERR: Pktlen(=%ld) was out of range (<0 or >%d); we must be out of sync.\n",pktlen,BUF_SZ); burn_off(ssd,xmlbuf); // Burn off the input read buffer, try to get back in sync continue; } if(bytes1 == 4) // The 1st read was successful { //usleep(500000); // Sleep 0.5 sec (give time for the xml message to show up) last_nowtime = nowtime; // Record the time we got this packet sync(); // Paranoia to improve the timely availability of the 2nd part bzero((char *)xmlbuf,sizeof(xmlbuf));// Clear the buffer if((bytes2=read(ssd,(char *)xmlbuf,pktlen)) < pktlen) // Read the VOEvent XML message (the 2nd read) { // Read too little if(bytes2 == -1) { printf( "%s ERR: 2nd read() returned -1. errno=%d=%s.\n",ut_ctime(tim),errno,strerror(errno)); fprintf(lg,"%s ERR: 2nd read() returned -1. errno=%d=%s.\n",ut_ctime(tim),errno,strerror(errno)); if(close(ssd)) { p = "%s ERR: close() failed (for the 2nd read problem). errno=%d=%s.\n"; printf( p,ut_ctime(tim),errno,strerror(errno)); fprintf(lg,p,ut_ctime(tim),errno,strerror(errno)); } ssd = -1; burn_off(ssd,xmlbuf); // Burn off the input read buffer, try to get back in sync continue; } else { p = "%s WARN: 2nd read: Did not read enough on the first attempt. bytes=%d pktlen=%ld.\n"; printf( p,ut_ctime(tim),bytes2,pktlen); fprintf(lg,p,ut_ctime(tim),bytes2,pktlen); usleep(500000); // Sleep 0.5 sec (give time for the remainder of the xml message to show up) if((bytes3=read(ssd,(char *)xmlbuf+bytes2,pktlen-bytes2)) < (pktlen-bytes2)) // Try to read more { p = "%s ERR: 3rd read: Did not read enough on the second attempt: bytes3=%d(!=pktlen-bytes=%ld), errno=%d=%s. Closing.\n"; printf( p,ut_ctime(tim),bytes3,pktlen-bytes2,errno,strerror(errno)); fprintf(lg,p,ut_ctime(tim),bytes3,pktlen-bytes2,errno,strerror(errno)); if(close(ssd)) { p = "%s ERR: close() failed (for the 3rd read problem). errno=%d=%s.\n"; printf( p,ut_ctime(tim),errno,strerror(errno)); fprintf(lg,p,ut_ctime(tim),errno,strerror(errno)); } ssd = -1; burn_off(ssd,xmlbuf); // Burn off the input read buffer, try to get back in sync continue; } else if(bytes3 == (pktlen-bytes2)) { printf( "OK: Got the remainder during the 3rd read attempt.\n"); fprintf(lg,"OK: Got the remainder during the 3rd read attempt.\n"); got_voe = 1; // Set flag that now we have a whole mesg to use } } } else if(bytes2 > pktlen) // Read too much { p = "%s ERR: 2nd read: really bad situation -- read too much. bytes=%d pktlen=%ld.\n"; printf( p,ut_ctime(tim),bytes2,pktlen); fprintf(lg,p,ut_ctime(tim),bytes2,pktlen); } else // Read just the right amount { printf( "%s 2nd read: Reading bytes from sd=%d...%d bytes.\n",ut_ctime(tim),ssd,bytes2); fprintf(lg,"%s 2nd read: Reading bytes from sd=%d...%d bytes.\n",ut_ctime(tim),ssd,bytes2); printf( "%s Got a new xml message from VOEvent server.\n",ut_ctime(tim)); fprintf(lg,"%s Got a new xml message from VOEvent server.\n",ut_ctime(tim)); got_voe = 1; } if(got_voe) // The single full read (or the two partial reads) yielded a voevent { // Print the xml messages and send back the ack (sorry, no checking, so no nack capability). printf( "%s\n",xmlbuf); fprintf(lg,"%s\n",xmlbuf); // If we got an imalive, then reply with the special imalive ack: if((strstr(xmlbuf,"iamalive") || strstr(xmlbuf,"imalive"))) // Allow both spellings of imalive { // The "ack" for an iamalive is different than an ack for a regular voevent: ackima = build_iamalive_response(); printf("\nResponse:\n%s\n",ackima); pktlen = strlen(ackima); netpktlen = htonl(pktlen); // Convert from local host order to network byte order printf("pktlen=%ld=0x%lX\n",pktlen,(unsigned long)pktlen); if((wbytes1=write(ssd,(char *)&netpktlen,4)) != 4) { p = "%s ERR: Iamalive response pktlen write: Bytes written=%d not equal to 4.\n"; printf( p,ut_ctime(tim),wbytes1); fprintf(lg,p,ut_ctime(tim),wbytes1); } else { printf( "%s Ack: Iamalive response pktlen written. wbytes1=%d\n",ut_ctime(tim),wbytes1); fprintf(lg,"%s Ack: Iamalive response pktlen written. wbytes1=%d\n",ut_ctime(tim),wbytes1); } if((wbytes2=write(ssd,(char *)ackima,pktlen)) != pktlen) { p = "%s ERR: Iamalive response ack write: Bytes written=%d not equal to %ld.\n"; printf( p,ut_ctime(tim),wbytes2,pktlen); fprintf(lg,p,ut_ctime(tim),wbytes2,pktlen); } else { printf( "%s Ack: Iamalive response ack written. wbytes2=%d\n",ut_ctime(tim),wbytes2); fprintf(lg,"%s Ack: Iamalive response ack written. wbytes2=%d\n",ut_ctime(tim),wbytes2); } } // Else reply with the regular ack: else { // If this demo program implemented validation, it would go here. ackbuf = build_voevent_response(xmlbuf); printf("\nResponse:\n%s\n",ackbuf); pktlen = strlen(ackbuf); netpktlen = htonl(pktlen); printf("pktlen=%ld=0x%lX\n",pktlen,(unsigned long)pktlen); if((wbytes1=write(ssd,(char *)&netpktlen,4)) != 4) { p = "%s ERR: VOEvent response pktlen write: Bytes written=%d not equal to 4.\n"; printf( p,ut_ctime(tim),wbytes1); fprintf(lg,p,ut_ctime(tim),wbytes1); } else { printf( "%s Ack: VOEvent response pktlen written. wbytes1=%d\n",ut_ctime(tim),wbytes1); fprintf(lg,"%s Ack: VOEvent response pktlen written. wbytes1=%d\n",ut_ctime(tim),wbytes1); } if((wbytes2=write(ssd,(char *)ackbuf,pktlen)) != pktlen) { p = "%s ERR: VOEvent response ack write: Bytes written=%d not equal to %ld.\n"; printf( p,ut_ctime(tim),wbytes2,pktlen); fprintf(lg,p,ut_ctime(tim),wbytes2,pktlen); } else { printf( "%s Ack: VOEvent response ack written. wbytes2=%d\n",ut_ctime(tim),wbytes2); fprintf(lg,"%s Ack: VOEvent response ack written. wbytes2=%d\n",ut_ctime(tim),wbytes2); } // THIS IS THE LOCATION WERE YOU CAN PARSE AND USE THE VOEVENT MESSAGE. } } //end of got_voe } //end of the read-something } //end of the start of the reading sequence else if((bytes1 == 0) && (errno != EWOULDBLOCK)) // Since the read is non-blocking, the read will return with the error EWOULDBLOCK(or EAGAIN), // but you want to continue checking for data. If the error is NOT EWOULDBLOCK, then there is a problem. { // The connection is broken p = "%s (bytes==0 && errno!=EWOULDBLOCK) errno=%d=%s ssd=%d.\n"; printf( p,ut_ctime(tim),errno,strerror(errno),ssd); fprintf(lg,p,ut_ctime(tim),errno,strerror(errno),ssd); brokenpipe(); // Handle any failure that we did not expect } else if((bytes1 == 0)) // If read returns no bytes and not even an EWOULDBLOCK, then there is a problem. { // The connection is broken printf( "%s (bytes==0) errno=%d=%s ssd=%d.\n",ut_ctime(tim),errno,strerror(errno),ssd); fprintf(lg,"%s (bytes==0) errno=%d=%s ssd=%d.\n",ut_ctime(tim),errno,strerror(errno),ssd); brokenpipe(); // Handle any failure that we did not expect } } //end of else connected // Check to see if regularly receiving imalive from TAN server (reset connection if not): if((nowtime - last_nowtime) > 200) // 3 times the imalive interval(60sec) plus 20 sec { printf( "WARN: It has been greater than 200 sec since the last (=%ld).\n", nowtime-last_nowtime); fprintf(lg,"WARN: It has been greater than 200 sec since the last (=%ld).\n", nowtime-last_nowtime); last_nowtime = nowtime; // Reset it so we don't get a million error statements brokenpipe(); // Close connection & cause the program to re-establish the connection } bzero((char *)xmlbuf,sizeof(xmlbuf)); // Clear the incoming VOEvent XML buffer // This sleep() is ONLY for this demo program. It should not be included // in your site's application code as it most definitely adds up to 1 sec // to the response time to the socket/packet servicing. sleep(1); // Give the CPU a rest } //end while(1) loop close(ssd); exit(0); } /*---------------------------------------------------------------------------*/ void brokenpipe() /* clean up after getting a brokenpipe signal */ { printf( "brokenpipe(): If this is the last line, then the shutdown() to GCN/TAN hung.\n"); fprintf(lg,"brokenpipe(): If this is the last line, then the shutdown() to GCN/TAN hung.\n"); if(shutdown(ssd,2) == -1) { perror("brokenpipe(): shutdown(): "); printf( "ERR: brokenpipe(): The shutdown did NOT work. errno=%d=%s\n",errno,strerror(errno)); fprintf(lg,"ERR: brokenpipe(): The shutdown did NOT work. errno=%d=%s\n",errno,strerror(errno)); } else { printf( "brokenpipe(): The shutdown worked OK.\n"); fprintf(lg,"brokenpipe(): The shutdown worked OK.\n"); } printf( "brokenpipe(): After the shutdown call; the shutdown didn't hang.\n"); fprintf(lg,"brokenpipe(): After the shutdown call; the shutdown didn't hang.\n"); if(close(ssd)) { printf( "ERR: close() problem in brokenpipe(), errno=%d=%s\n",errno,strerror(errno)); fprintf(lg,"ERR: close() problem in brokenpipe(), errno=%d=%s\n",errno,strerror(errno)); } ssd = -1; } /*---------------------------------------------------------------------------*/ void establish_server_conn() /* Establish a connection to the server */ { if((ssd = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP)) < 0) { printf( "ERR: client: can NOT open stream socket. errno=%d=%s.\n",errno,strerror(errno)); fprintf(lg,"ERR: client: can NOT open stream socket. errno=%d=%s.\n",errno,strerror(errno)); } if(connect(ssd,(struct sockaddr *) &serv_addr,sizeof(serv_addr)) < 0) { printf( "ERR: client: can NOT connect to server. errno=%d=%s.\n",errno,strerror(errno)); fprintf(lg,"ERR: client: can NOT connect to server. errno=%d=%s.\n",errno,strerror(errno)); // Reset ssd = -1 so that the loop will keep trying to connect ssd = -1; } else { printf( "Client connected to server. ssd=%d\n",ssd); fprintf(lg,"Client connected to server. ssd=%d\n",ssd); // Make the connection non-blocking: if(ioctl(ssd, FIONBIO, &on) < 0) { printf( "ERR: establish_server_conn(): ioctl(): errno=%d=%s.\n",errno,strerror(errno)); fprintf(lg,"ERR: establish_server_conn(): ioctl(): errno=%d=%s.\n",errno,strerror(errno)); } } } /*---------------------------------------------------------------------------*/ // The assumption is: If we called this routine, we got some spurious value // for 'pktlen' (for the amount of stuff to read), so we must be out of sync // with the basic sequence of (a) 4-byte value of N-byte in the voevent message, and // (b) those N bytes of the message. This will clear out the input buffer // (hopefully faster than new stuff can arrive) so that it will get back into // that two-part read sequence again. // This (simple) technique does not work on some machines/op_sys. void burn_off(sd,buf) /* Burn off the input read buffer, try to get back in sync */ int sd; // The file dscriptor on which to read() char *buf; // Ptr ot a buffer to put the read-in stuff { int flag; // Flag to control the while-loop int nbytes; // How many bytes did we read flag = 1; while(flag) { nbytes = read(sd,(char *)buf,BUF_SZ); printf( "Burned off %d bytes.\n",nbytes); fprintf(lg,"Burned off %d bytes.\n",nbytes); if(nbytes == 0) // If nothing left, then exit this loop { printf( "Nothing left to read; will exit this burn-off loop.\n"); fprintf(lg,"Nothing left to read; will exit this burn-off loop.\n"); flag = 0; } if(flag++ > 10) // Safety measure to prevent infinite loop { printf( "Exceeded 10-cnt in the burn-off loop; will exit this burn-off loop.\n"); fprintf(lg,"Exceeded 10-cnt in the burn-off loop; will exit this burn-off loop.\n"); flag = 0; } } } /*---------------------------------------------------------------------------*/ // Drop the 'year' field back down to a 2-digit quantity. struct tm * fixedgmtime(nowtime) /* FIXED GMTIME() wrapper */ time_t *nowtime; { static struct tm fixed; struct tm *tm; tm = gmtime(nowtime); bcopy((char *)tm,(char *)(&fixed),sizeof(struct tm)); fixed.tm_year -= 100; // eg converts 112 to 12 return((struct tm *)(&fixed)); } /*---------------------------------------------------------------------------*/ char * ut_ctime(struct tm *tim) /* convert TimeStruct into yy/mm/dd hh:mm:ss string */ { static char ymdhms[50]; // Permanent place to build the string // Day dd Mmm yy hh:mm:ss UT e.g. Wed 15 Feb 12 19:22:21 UT strftime(ymdhms,42,"%a %d %h %y %H:%M:%S UT",tim); // Put the time in a nice format return(ymdhms); } /*---------------------------------------------------------------------------*/ // The "ack" response to an iamalive message is different than to a regular VOEvent. // This is because 'iamalives' are considered to be 'transport' messages, // and not real/regular VOEvent messages. // See http://www.ivoa.net/Documents/Notes/VOEventTransport/ char * build_iamalive_response() /* Build Iamalive Response */ { time_t nowtime; // The current system time struct tm *tim,*fixedgmtime(); // Ptr to structure of current UT values static char ack_buf[10000]; // Buffer to hold the complete iamalive message response time(&nowtime); // Get the system time for the notice timestamp tim = fixedgmtime(&nowtime); bzero((char *)ack_buf,sizeof(ack_buf));// Clears the buffer (paranoia) sprintf(ack_buf,"\n\nivo://nasa.gsfc.gcn/GCN#\n%s\n20%02d-%02d-%02dT%02d:%02d:%02d\n\n\n\n\n", ack_subivo, tim->tm_year, tim->tm_mon+1, tim->tm_mday, tim->tm_hour, tim->tm_min, tim->tm_sec, ack_ipaddr, ack_contact); return(ack_buf); } /*---------------------------------------------------------------------------*/ char * build_voevent_response(char *buf) /* Build VOEvent Message Response */ { time_t nowtime; // The current system time struct tm *tim,*fixedgmtime(); // Ptr to structure of current UT values static char ack_buf[10000]; // Buffer to hold the complete voevent message response char *ack_ivorn; // Origin is the IVORN of the just received VOEvent message ack_ivorn = extract_ivorn(buf); //printf("ack_ivorn=%s\n",ack_ivorn); time(&nowtime); // Get the system time for the notice timestamp tim = fixedgmtime(&nowtime); bzero((char *)ack_buf,sizeof(ack_buf)); // Clears the buffer (paranoia) sprintf(ack_buf,"\n\n%s\n%s\n20%02d-%02d-%02dT%02d:%02d:%02d\n\n\n\n%s\n\n", ack_ivorn, ack_subivo, tim->tm_year, tim->tm_mon+1, tim->tm_mday, tim->tm_hour, tim->tm_min, tim->tm_sec, ack_ipaddr, ack_contact, ack_result_mesg); return(ack_buf); } /*---------------------------------------------------------------------------*/ // The ivorn in the VOEvent Message is contained between double quotes after the phrase ivorn= char * extract_ivorn(char *buf) /* Extract Ivorn from voevent message */ { static char ivornbuf[500]; // Buffer to hold the complete voevent message response char *p; // Temporary pointer int i; // Loop counter time_t nowtime; // The current system time struct tm *tim,*fixedgmtime(); // Ptr to structure of current UT values time(&nowtime); // Get the system time for the notice timestamp tim = fixedgmtime(&nowtime); for(i=0;i<500;i++) ivornbuf[i] = 0; // Clears the buffer (paranoia) //printf("extract_ivorn(): buf=\n%s\n",buf); p = strstr(buf,"ivorn="); if(p == NULL) { printf( "%s ERR: extract_ivorn(): Could not find Ivorn in the VOEvent Message.\n",ut_ctime(tim)); fprintf(lg,"%s ERR: extract_ivorn(): Could not find Ivorn in the VOEvent Message.\n",ut_ctime(tim)); ivornbuf[0]='\0'; } else { strncpy(ivornbuf,p+7,499); // Use ptr arith to get to the right place p = strstr(ivornbuf,"\'"); // Check for either single or double quote mark if(p == NULL) p = strstr(ivornbuf,"\""); if(p == NULL) ivornbuf[499]='\0'; else *p = '\0'; } return(ivornbuf); }