/* $Id: lbapi.c,v 1.11 1999/02/26 21:17:36 shavirin Exp $ * =========================================================================== * * PUBLIC DOMAIN NOTICE * National Center for Biotechnology Information * * This software/database is a "United States Government Work" under the * terms of the United States Copyright Act. It was written as part of * the author's official duties as a United States Government employee and * thus cannot be copyrighted. This software/database is freely available * to the public for use. The National Library of Medicine and the U.S. * Government have not placed any restriction on its use or reproduction. * * Although all reasonable efforts have been taken to ensure the accuracy * and reliability of the software and data, the NLM and the U.S. * Government do not and cannot warrant the performance or results that * may be obtained by using this software or data. The NLM and the U.S. * Government disclaim all warranties, express or implied, including * warranties of performance, merchantability or fitness for any particular * purpose. * * Please cite the author in any work or product based on this material. * * =========================================================================== * * File Name: $RCSfile: lbapi.c,v $ * * Author: Sergei Shavirin * * Initial Version Creation Date: 03/24/1997 * * $Revision: 1.11 $ * * File Description: * Utilities for the load balancing client library * * $Log: lbapi.c,v $ * Revision 1.11 1999/02/26 21:17:36 shavirin * Moved al ntohl function to the lbdaemon area. * * Revision 1.10 1999/02/02 21:10:28 shavirin * Changed formula to calculate status: * Added adjustment of load and used 4th lb-parameter. * * Revision 1.9 1998/12/07 19:01:50 shavirin * Added complience with little-big endian platforms. * * Revision 1.8 1998/09/22 17:22:57 yaschenk * LBCalculateStatus: changed additive constant 1 which is very high to 0.01 * * Revision 1.7 1998/05/08 15:26:57 vakatov * [LB_DIRECT] now can skip IP addresses(for the dispatcher hosts) which * were already offered by the load-balancing daemon but failed by some reason * * Revision 1.6 1998/04/23 14:26:18 shavirin * Added include #include * * Revision 1.5 1998/04/07 14:17:27 vakatov * Skip all code(#ifdef'd) if LB_DIRECT is not defined or if compiled on * any platform but Solaris and IRIX * * Revision 1.4 1998/04/03 21:50:08 shavirin * Added include file for TCP/IP address define * * Revision 1.3 1998/04/03 21:16:47 vakatov * Cleaned up the code and prepared "lbapi.[ch]" to be moved to "netcli" lib * * Revision 1.2 1998/04/02 17:36:04 yaschenk * Adding dispd-ncbid shortcut when they are on the same server, adding preference to same server in stateless mode * * Revision 1.1 1998/03/06 18:54:25 shavirin * Initial revision * ========================================================================== */ #include #ifdef LB_DIRECT #include #include #include #include #include #include #include #include #include #include #define SHM_FLAGS ((SHM_R >> 6) | (SHM_R >> 3) | SHM_R) #define MAX_RAND_NUMBER 0x7FFF typedef struct LBUserInfo { LB_MessagePtr lbtable; int shmemid; } LBUserInfo, *LBUserInfoPtr; typedef struct LBStatus { int index; float status; int skip; } LBStatus, *LBStatusPtr; static LBUserInfo theinfo; static float LBCalculateStatus(LB_MessagePtr msgp) { float status; int cpuload; /* Penalize machine if load[0]/256 > load[1] */ cpuload = msgp->load[0]; if(msgp->load[0] > (msgp->load[1]<<8)) cpuload *= exp(msgp->load[0] / (256.0*msgp->load[1]) - 1.0); status = 0.01 + 256000*msgp->load[1] / (float)(cpuload*msgp->load[2] + 1); status = status * msgp->load[3]; return status; } static int LBClientInit(void) { /* setting it completely random */ srand(time(NULL)); if ((theinfo.shmemid = shmget(LB_SHARED_KEY, sizeof(LB_Message) * MAX_NUM_HOSTS, SHM_FLAGS)) < 0) return -1; if ((theinfo.lbtable = (LB_MessagePtr) shmat(theinfo.shmemid, (void *)0, SHM_RDONLY)) == (LB_MessagePtr)-1) return -1; return 0; } extern int LBPrintTable(void) { int i, j; struct sockaddr_in sin; struct hostent *hp; float status; LB_MessagePtr lbtable; if((lbtable = theinfo.lbtable) == NULL) { if(LBClientInit() < 0) return -1; lbtable = theinfo.lbtable; } for(j = 0; j < MAX_NUM_HOSTS; j++) { if(lbtable[j].address != 0) { sin.sin_addr.s_addr = lbtable[j].address; hp = gethostbyaddr((char *)&sin.sin_addr, sizeof (sin.sin_addr), AF_INET); printf("%-15s: ", hp == NULL? inet_ntoa(sin.sin_addr) : hp->h_name); status = LBCalculateStatus(&lbtable[j]); printf("%-10.2f ", status); for(i = 0; i < NUM_LOAD_PARAMETERS; i++) printf("%5d ", lbtable[j].load[i]); for(i = 0; i < MAX_NUM_SERVICES; i++) { if(*lbtable[j].service[i] != '\0') printf("%s ", lbtable[j].service[i]); } printf("\n"); fflush(stdout); } } printf("----\n"); return 0; } extern unsigned LBGetIPAddress(const char *service, unsigned int pref_ip, unsigned *skip_ip, size_t n_skip) { int i, j, k; LBStatus trace[MAX_NUM_HOSTS]; int count; float status, all_status, point; LB_MessagePtr lbtable; if (!theinfo.lbtable && LBClientInit() < 0) return 0; lbtable = theinfo.lbtable; memset(trace, '\0', sizeof(trace)); /* the hosts to be skipped */ for (j = 0; j < MAX_NUM_HOSTS; j++) { size_t m; for (m = 0; m < n_skip; m++) if (lbtable[j].address == skip_ip[m]) { trace[j].skip = 1; break; } } /* first try to find the preferred address */ if ( pref_ip ) { for (j = 0, i = 0; j < MAX_NUM_HOSTS; j++) { if (pref_ip == lbtable[j].address) { if ( trace[j].skip ) break; for (k = 0; k < MAX_NUM_SERVICES; k++) { if ( !strcmp(lbtable[j].service[k], service) ) return pref_ip; } break; } } } all_status = 0; for (j = 0, i = 0; j < MAX_NUM_HOSTS; j++) { if ( trace[j].skip ) continue; for (k = 0; k < MAX_NUM_SERVICES; k++) { if(!strcmp(lbtable[j].service[k], service)) { status = LBCalculateStatus(&lbtable[j]); all_status += status; trace[i].status = all_status; trace[i].index = j; i++; break; } } } if ( !i ) return 0; count = i; point = (float)(trace[count-1].status * rand()) / (float)MAX_RAND_NUMBER; for (i = 0; i < count; i++) { if (point < trace[i].status) break; } return lbtable[trace[i].index].address; } #endif /* LB_DIRECT */