1*0Sstevel@tonic-gate /* 2*0Sstevel@tonic-gate * CDDL HEADER START 3*0Sstevel@tonic-gate * 4*0Sstevel@tonic-gate * The contents of this file are subject to the terms of the 5*0Sstevel@tonic-gate * Common Development and Distribution License, Version 1.0 only 6*0Sstevel@tonic-gate * (the "License"). You may not use this file except in compliance 7*0Sstevel@tonic-gate * with the License. 8*0Sstevel@tonic-gate * 9*0Sstevel@tonic-gate * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE 10*0Sstevel@tonic-gate * or http://www.opensolaris.org/os/licensing. 11*0Sstevel@tonic-gate * See the License for the specific language governing permissions 12*0Sstevel@tonic-gate * and limitations under the License. 13*0Sstevel@tonic-gate * 14*0Sstevel@tonic-gate * When distributing Covered Code, include this CDDL HEADER in each 15*0Sstevel@tonic-gate * file and include the License file at usr/src/OPENSOLARIS.LICENSE. 16*0Sstevel@tonic-gate * If applicable, add the following below this CDDL HEADER, with the 17*0Sstevel@tonic-gate * fields enclosed by brackets "[]" replaced with your own identifying 18*0Sstevel@tonic-gate * information: Portions Copyright [yyyy] [name of copyright owner] 19*0Sstevel@tonic-gate * 20*0Sstevel@tonic-gate * CDDL HEADER END 21*0Sstevel@tonic-gate */ 22*0Sstevel@tonic-gate /* 23*0Sstevel@tonic-gate * Copyright 2003 Sun Microsystems, Inc. All rights reserved. 24*0Sstevel@tonic-gate * Use is subject to license terms. 25*0Sstevel@tonic-gate */ 26*0Sstevel@tonic-gate 27*0Sstevel@tonic-gate /* Copyright (c) 1984, 1986, 1987, 1988, 1989 AT&T */ 28*0Sstevel@tonic-gate /* All Rights Reserved */ 29*0Sstevel@tonic-gate 30*0Sstevel@tonic-gate /* 31*0Sstevel@tonic-gate * University Copyright- Copyright (c) 1982, 1986, 1988 32*0Sstevel@tonic-gate * The Regents of the University of California 33*0Sstevel@tonic-gate * All Rights Reserved 34*0Sstevel@tonic-gate * 35*0Sstevel@tonic-gate * University Acknowledgment- Portions of this document are derived from 36*0Sstevel@tonic-gate * software developed by the University of California, Berkeley, and its 37*0Sstevel@tonic-gate * contributors. 38*0Sstevel@tonic-gate */ 39*0Sstevel@tonic-gate 40*0Sstevel@tonic-gate #pragma ident "%Z%%M% %I% %E% SMI" 41*0Sstevel@tonic-gate 42*0Sstevel@tonic-gate /* 43*0Sstevel@tonic-gate * Send query to name server and wait for reply. 44*0Sstevel@tonic-gate */ 45*0Sstevel@tonic-gate 46*0Sstevel@tonic-gate #include "synonyms.h" 47*0Sstevel@tonic-gate 48*0Sstevel@tonic-gate #include <sys/param.h> 49*0Sstevel@tonic-gate #include <sys/time.h> 50*0Sstevel@tonic-gate #include <sys/socket.h> 51*0Sstevel@tonic-gate #include <sys/uio.h> 52*0Sstevel@tonic-gate #include <sys/stat.h> 53*0Sstevel@tonic-gate #include <netinet/in.h> 54*0Sstevel@tonic-gate #include <stdio.h> 55*0Sstevel@tonic-gate #include <errno.h> 56*0Sstevel@tonic-gate #include <arpa/nameser.h> 57*0Sstevel@tonic-gate #include <resolv.h> 58*0Sstevel@tonic-gate 59*0Sstevel@tonic-gate 60*0Sstevel@tonic-gate static int s = -1; /* socket used for communications */ 61*0Sstevel@tonic-gate static struct sockaddr no_addr; 62*0Sstevel@tonic-gate 63*0Sstevel@tonic-gate 64*0Sstevel@tonic-gate #ifndef FD_SET 65*0Sstevel@tonic-gate #define NFDBITS 32 66*0Sstevel@tonic-gate #define FD_SETSIZE 32 67*0Sstevel@tonic-gate #define FD_SET(n, p) ((p)->fds_bits[(n)/NFDBITS] |= (1 << ((n) % NFDBITS))) 68*0Sstevel@tonic-gate #define FD_CLR(n, p) ((p)->fds_bits[(n)/NFDBITS] &= ~(1 << ((n) % NFDBITS))) 69*0Sstevel@tonic-gate #define FD_ISSET(n, p) ((p)->fds_bits[(n)/NFDBITS] & (1 << ((n) % NFDBITS))) 70*0Sstevel@tonic-gate #ifdef SYSV 71*0Sstevel@tonic-gate #define FD_ZERO(p) memset((void *)(p), 0, sizeof (*(p))) 72*0Sstevel@tonic-gate #else 73*0Sstevel@tonic-gate #define FD_ZERO(p) bzero((char *)(p), sizeof (*(p))) 74*0Sstevel@tonic-gate #endif 75*0Sstevel@tonic-gate #endif 76*0Sstevel@tonic-gate 77*0Sstevel@tonic-gate /* 78*0Sstevel@tonic-gate * 1247019: Kludge to time out quickly if there is no /etc/resolv.conf 79*0Sstevel@tonic-gate * and a TCP connection to the local DNS server fails. 80*0Sstevel@tonic-gate */ 81*0Sstevel@tonic-gate 82*0Sstevel@tonic-gate static int _confcheck() 83*0Sstevel@tonic-gate { 84*0Sstevel@tonic-gate int ns; 85*0Sstevel@tonic-gate struct stat rc_stat; 86*0Sstevel@tonic-gate struct sockaddr_in ns_sin; 87*0Sstevel@tonic-gate 88*0Sstevel@tonic-gate 89*0Sstevel@tonic-gate /* First, we check to see if /etc/resolv.conf exists. 90*0Sstevel@tonic-gate * If it doesn't, then localhost is mostlikely to be 91*0Sstevel@tonic-gate * the nameserver. 92*0Sstevel@tonic-gate */ 93*0Sstevel@tonic-gate if (stat(_PATH_RESCONF, &rc_stat) == -1 && errno == ENOENT) { 94*0Sstevel@tonic-gate 95*0Sstevel@tonic-gate /* Next, we check to see if _res.nsaddr is set to loopback. 96*0Sstevel@tonic-gate * If it isn't, it has been altered by the application 97*0Sstevel@tonic-gate * explicitly and we then want to bail with success. 98*0Sstevel@tonic-gate */ 99*0Sstevel@tonic-gate if (_res.nsaddr.sin_addr.S_un.S_addr == htonl(INADDR_LOOPBACK)) { 100*0Sstevel@tonic-gate 101*0Sstevel@tonic-gate /* Lastly, we try to connect to the TCP port of the 102*0Sstevel@tonic-gate * nameserver. If this fails, then we know that 103*0Sstevel@tonic-gate * DNS is misconfigured and we can quickly exit. 104*0Sstevel@tonic-gate */ 105*0Sstevel@tonic-gate ns = socket(AF_INET, SOCK_STREAM, 0); 106*0Sstevel@tonic-gate IN_SET_LOOPBACK_ADDR(&ns_sin); 107*0Sstevel@tonic-gate ns_sin.sin_port = htons(NAMESERVER_PORT); 108*0Sstevel@tonic-gate if (connect(ns, (struct sockaddr *) &ns_sin, 109*0Sstevel@tonic-gate sizeof ns_sin) == -1) { 110*0Sstevel@tonic-gate close(ns); 111*0Sstevel@tonic-gate return(-1); 112*0Sstevel@tonic-gate } 113*0Sstevel@tonic-gate else { 114*0Sstevel@tonic-gate close(ns); 115*0Sstevel@tonic-gate return(0); 116*0Sstevel@tonic-gate } 117*0Sstevel@tonic-gate } 118*0Sstevel@tonic-gate 119*0Sstevel@tonic-gate return(0); 120*0Sstevel@tonic-gate } 121*0Sstevel@tonic-gate 122*0Sstevel@tonic-gate return (0); 123*0Sstevel@tonic-gate } 124*0Sstevel@tonic-gate 125*0Sstevel@tonic-gate res_send(buf, buflen, answer, anslen) 126*0Sstevel@tonic-gate char *buf; 127*0Sstevel@tonic-gate int buflen; 128*0Sstevel@tonic-gate char *answer; 129*0Sstevel@tonic-gate int anslen; 130*0Sstevel@tonic-gate { 131*0Sstevel@tonic-gate register int n; 132*0Sstevel@tonic-gate int try, v_circuit, resplen, ns; 133*0Sstevel@tonic-gate int gotsomewhere = 0, connected = 0; 134*0Sstevel@tonic-gate int connreset = 0; 135*0Sstevel@tonic-gate u_short id, len; 136*0Sstevel@tonic-gate char *cp; 137*0Sstevel@tonic-gate fd_set dsmask; 138*0Sstevel@tonic-gate struct timeval timeout; 139*0Sstevel@tonic-gate HEADER *hp = (HEADER *) buf; 140*0Sstevel@tonic-gate HEADER *anhp = (HEADER *) answer; 141*0Sstevel@tonic-gate struct iovec iov[2]; 142*0Sstevel@tonic-gate int terrno = ETIMEDOUT; 143*0Sstevel@tonic-gate char junk[512]; 144*0Sstevel@tonic-gate 145*0Sstevel@tonic-gate #ifdef DEBUG 146*0Sstevel@tonic-gate if (_res.options & RES_DEBUG) { 147*0Sstevel@tonic-gate printf("res_send()\n"); 148*0Sstevel@tonic-gate p_query(buf); 149*0Sstevel@tonic-gate } 150*0Sstevel@tonic-gate #endif DEBUG 151*0Sstevel@tonic-gate if (!(_res.options & RES_INIT)) 152*0Sstevel@tonic-gate if (res_init() == -1) { 153*0Sstevel@tonic-gate return (-1); 154*0Sstevel@tonic-gate } 155*0Sstevel@tonic-gate 156*0Sstevel@tonic-gate /* 1247019: Check to see if we can bailout quickly. */ 157*0Sstevel@tonic-gate if (_confcheck() == -1) 158*0Sstevel@tonic-gate return(-1); 159*0Sstevel@tonic-gate 160*0Sstevel@tonic-gate v_circuit = (_res.options & RES_USEVC) || buflen > PACKETSZ; 161*0Sstevel@tonic-gate id = hp->id; 162*0Sstevel@tonic-gate /* 163*0Sstevel@tonic-gate * Send request, RETRY times, or until successful 164*0Sstevel@tonic-gate */ 165*0Sstevel@tonic-gate for (try = 0; try < _res.retry; try++) { 166*0Sstevel@tonic-gate for (ns = 0; ns < _res.nscount; ns++) { 167*0Sstevel@tonic-gate #ifdef DEBUG 168*0Sstevel@tonic-gate if (_res.options & RES_DEBUG) 169*0Sstevel@tonic-gate printf("Querying server (# %d) address = %s\n", 170*0Sstevel@tonic-gate ns+1, inet_ntoa(_res.nsaddr_list[ns].sin_addr)); 171*0Sstevel@tonic-gate #endif DEBUG 172*0Sstevel@tonic-gate usevc: 173*0Sstevel@tonic-gate if (v_circuit) { 174*0Sstevel@tonic-gate int truncated = 0; 175*0Sstevel@tonic-gate 176*0Sstevel@tonic-gate /* 177*0Sstevel@tonic-gate * Use virtual circuit; 178*0Sstevel@tonic-gate * at most one attempt per server. 179*0Sstevel@tonic-gate */ 180*0Sstevel@tonic-gate try = _res.retry; 181*0Sstevel@tonic-gate if (s < 0) { 182*0Sstevel@tonic-gate s = _socket(AF_INET, SOCK_STREAM, 0); 183*0Sstevel@tonic-gate if (s < 0) { 184*0Sstevel@tonic-gate terrno = errno; 185*0Sstevel@tonic-gate #ifdef DEBUG 186*0Sstevel@tonic-gate if (_res.options & RES_DEBUG) { 187*0Sstevel@tonic-gate perror("socket (vc) failed"); 188*0Sstevel@tonic-gate } 189*0Sstevel@tonic-gate #endif DEBUG 190*0Sstevel@tonic-gate continue; 191*0Sstevel@tonic-gate } 192*0Sstevel@tonic-gate if (connect(s, (struct sockaddr *) &_res.nsaddr_list[ns], 193*0Sstevel@tonic-gate sizeof (struct sockaddr)) < 0) { 194*0Sstevel@tonic-gate terrno = errno; 195*0Sstevel@tonic-gate #ifdef DEBUG 196*0Sstevel@tonic-gate if (_res.options & RES_DEBUG) { 197*0Sstevel@tonic-gate perror("connect failed"); 198*0Sstevel@tonic-gate } 199*0Sstevel@tonic-gate #endif DEBUG 200*0Sstevel@tonic-gate (void) close(s); 201*0Sstevel@tonic-gate s = -1; 202*0Sstevel@tonic-gate continue; 203*0Sstevel@tonic-gate } 204*0Sstevel@tonic-gate } 205*0Sstevel@tonic-gate /* 206*0Sstevel@tonic-gate * Send length & message 207*0Sstevel@tonic-gate */ 208*0Sstevel@tonic-gate len = htons((u_short)buflen); 209*0Sstevel@tonic-gate iov[0].iov_base = (caddr_t)&len; 210*0Sstevel@tonic-gate iov[0].iov_len = sizeof (len); 211*0Sstevel@tonic-gate iov[1].iov_base = buf; 212*0Sstevel@tonic-gate iov[1].iov_len = buflen; 213*0Sstevel@tonic-gate if (writev(s, iov, 2) != sizeof (len) + 214*0Sstevel@tonic-gate buflen) { 215*0Sstevel@tonic-gate terrno = errno; 216*0Sstevel@tonic-gate #ifdef DEBUG 217*0Sstevel@tonic-gate if (_res.options & RES_DEBUG) 218*0Sstevel@tonic-gate perror("write failed"); 219*0Sstevel@tonic-gate #endif DEBUG 220*0Sstevel@tonic-gate (void) close(s); 221*0Sstevel@tonic-gate s = -1; 222*0Sstevel@tonic-gate continue; 223*0Sstevel@tonic-gate } 224*0Sstevel@tonic-gate /* 225*0Sstevel@tonic-gate * Receive length & response 226*0Sstevel@tonic-gate */ 227*0Sstevel@tonic-gate cp = answer; 228*0Sstevel@tonic-gate len = sizeof (short); 229*0Sstevel@tonic-gate while (len != 0 && (n = read 230*0Sstevel@tonic-gate (s, (char *)cp, (int)len)) > 0) { 231*0Sstevel@tonic-gate cp += n; 232*0Sstevel@tonic-gate len -= n; 233*0Sstevel@tonic-gate } 234*0Sstevel@tonic-gate if (n <= 0) { 235*0Sstevel@tonic-gate terrno = errno; 236*0Sstevel@tonic-gate #ifdef DEBUG 237*0Sstevel@tonic-gate if (_res.options & RES_DEBUG) 238*0Sstevel@tonic-gate perror("read failed"); 239*0Sstevel@tonic-gate #endif DEBUG 240*0Sstevel@tonic-gate (void) close(s); 241*0Sstevel@tonic-gate s = -1; 242*0Sstevel@tonic-gate /* 243*0Sstevel@tonic-gate * A long running process might get its TCP 244*0Sstevel@tonic-gate * connection reset if the remote server was 245*0Sstevel@tonic-gate * restarted. Requery the server instead of 246*0Sstevel@tonic-gate * trying a new one. When there is only one 247*0Sstevel@tonic-gate * server, this means that a query might work 248*0Sstevel@tonic-gate * instead of failing. We only allow one reset 249*0Sstevel@tonic-gate * per query to prevent looping. 250*0Sstevel@tonic-gate */ 251*0Sstevel@tonic-gate if (terrno == ECONNRESET && 252*0Sstevel@tonic-gate !connreset) { 253*0Sstevel@tonic-gate connreset = 1; 254*0Sstevel@tonic-gate ns--; 255*0Sstevel@tonic-gate } 256*0Sstevel@tonic-gate continue; 257*0Sstevel@tonic-gate } 258*0Sstevel@tonic-gate cp = answer; 259*0Sstevel@tonic-gate if ((resplen = ntohs(*(u_short *)cp)) > 260*0Sstevel@tonic-gate anslen) { 261*0Sstevel@tonic-gate #ifdef DEBUG 262*0Sstevel@tonic-gate if (_res.options & RES_DEBUG) 263*0Sstevel@tonic-gate fprintf(stderr, 264*0Sstevel@tonic-gate "response truncated\n"); 265*0Sstevel@tonic-gate #endif DEBUG 266*0Sstevel@tonic-gate len = anslen; 267*0Sstevel@tonic-gate truncated = 1; 268*0Sstevel@tonic-gate } else 269*0Sstevel@tonic-gate len = resplen; 270*0Sstevel@tonic-gate while (len != 0 && 271*0Sstevel@tonic-gate (n = read(s, (char *)cp, 272*0Sstevel@tonic-gate (int)len)) > 0) { 273*0Sstevel@tonic-gate cp += n; 274*0Sstevel@tonic-gate len -= n; 275*0Sstevel@tonic-gate } 276*0Sstevel@tonic-gate if (n <= 0) { 277*0Sstevel@tonic-gate terrno = errno; 278*0Sstevel@tonic-gate #ifdef DEBUG 279*0Sstevel@tonic-gate if (_res.options & RES_DEBUG) 280*0Sstevel@tonic-gate perror("read failed"); 281*0Sstevel@tonic-gate #endif DEBUG 282*0Sstevel@tonic-gate (void) close(s); 283*0Sstevel@tonic-gate s = -1; 284*0Sstevel@tonic-gate continue; 285*0Sstevel@tonic-gate } 286*0Sstevel@tonic-gate if (truncated) { 287*0Sstevel@tonic-gate /* 288*0Sstevel@tonic-gate * Flush rest of answer 289*0Sstevel@tonic-gate * so connection stays in synch. 290*0Sstevel@tonic-gate */ 291*0Sstevel@tonic-gate anhp->tc = 1; 292*0Sstevel@tonic-gate len = resplen - anslen; 293*0Sstevel@tonic-gate /* 294*0Sstevel@tonic-gate * set the value of resplen to anslen, 295*0Sstevel@tonic-gate * this is done because the caller 296*0Sstevel@tonic-gate * assumes resplen contains the size of 297*0Sstevel@tonic-gate * message read into the "answer" buffer 298*0Sstevel@tonic-gate * passed in. 299*0Sstevel@tonic-gate */ 300*0Sstevel@tonic-gate resplen = anslen; 301*0Sstevel@tonic-gate 302*0Sstevel@tonic-gate while (len != 0) { 303*0Sstevel@tonic-gate n = (len > sizeof (junk) ? 304*0Sstevel@tonic-gate sizeof (junk) : len); 305*0Sstevel@tonic-gate if ((n = read(s, junk, n)) > 0) 306*0Sstevel@tonic-gate len -= n; 307*0Sstevel@tonic-gate else 308*0Sstevel@tonic-gate break; 309*0Sstevel@tonic-gate } 310*0Sstevel@tonic-gate } 311*0Sstevel@tonic-gate } else { 312*0Sstevel@tonic-gate /* 313*0Sstevel@tonic-gate * Use datagrams. 314*0Sstevel@tonic-gate */ 315*0Sstevel@tonic-gate if (s < 0) { 316*0Sstevel@tonic-gate s = _socket(AF_INET, SOCK_DGRAM, 0); 317*0Sstevel@tonic-gate if (s < 0) { 318*0Sstevel@tonic-gate terrno = errno; 319*0Sstevel@tonic-gate #ifdef DEBUG 320*0Sstevel@tonic-gate if (_res.options & RES_DEBUG) { 321*0Sstevel@tonic-gate perror("socket (dg) failed"); 322*0Sstevel@tonic-gate } 323*0Sstevel@tonic-gate #endif DEBUG 324*0Sstevel@tonic-gate continue; 325*0Sstevel@tonic-gate } 326*0Sstevel@tonic-gate } 327*0Sstevel@tonic-gate #if BSD >= 43 328*0Sstevel@tonic-gate /* 329*0Sstevel@tonic-gate * I'm tired of answering this question, so: 330*0Sstevel@tonic-gate * On a 4.3BSD+ machine (client and server, 331*0Sstevel@tonic-gate * actually), sending to a nameserver datagram 332*0Sstevel@tonic-gate * port with no nameserver will cause an 333*0Sstevel@tonic-gate * ICMP port unreachable message to be returned. 334*0Sstevel@tonic-gate * If our datagram socket is "connected" to the 335*0Sstevel@tonic-gate * server, we get an ECONNREFUSED error on the next 336*0Sstevel@tonic-gate * socket operation, and select returns if the 337*0Sstevel@tonic-gate * error message is received. We can thus detect 338*0Sstevel@tonic-gate * the absence of a nameserver without timing out. 339*0Sstevel@tonic-gate * If we have sent queries to at least two servers, 340*0Sstevel@tonic-gate * however, we don't want to remain connected, 341*0Sstevel@tonic-gate * as we wish to receive answers from the first 342*0Sstevel@tonic-gate * server to respond. 343*0Sstevel@tonic-gate */ 344*0Sstevel@tonic-gate if (_res.nscount == 1 || 345*0Sstevel@tonic-gate (try == 0 && ns == 0)) { 346*0Sstevel@tonic-gate /* 347*0Sstevel@tonic-gate * Don't use connect if we might 348*0Sstevel@tonic-gate * still receive a response 349*0Sstevel@tonic-gate * from another server. 350*0Sstevel@tonic-gate */ 351*0Sstevel@tonic-gate if (connected == 0) { 352*0Sstevel@tonic-gate if (connect(s, 353*0Sstevel@tonic-gate (struct sockaddr *) &_res.nsaddr_list[ns], 354*0Sstevel@tonic-gate sizeof (struct sockaddr)) < 0) { 355*0Sstevel@tonic-gate #ifdef DEBUG 356*0Sstevel@tonic-gate if (_res.options & 357*0Sstevel@tonic-gate RES_DEBUG) { 358*0Sstevel@tonic-gate perror("connect"); 359*0Sstevel@tonic-gate } 360*0Sstevel@tonic-gate #endif DEBUG 361*0Sstevel@tonic-gate continue; 362*0Sstevel@tonic-gate } 363*0Sstevel@tonic-gate connected = 1; 364*0Sstevel@tonic-gate } 365*0Sstevel@tonic-gate if (send(s, buf, buflen, 0) != buflen) { 366*0Sstevel@tonic-gate #ifdef DEBUG 367*0Sstevel@tonic-gate if (_res.options & RES_DEBUG) 368*0Sstevel@tonic-gate perror("send"); 369*0Sstevel@tonic-gate #endif DEBUG 370*0Sstevel@tonic-gate continue; 371*0Sstevel@tonic-gate } 372*0Sstevel@tonic-gate } else { 373*0Sstevel@tonic-gate /* 374*0Sstevel@tonic-gate * Disconnect if we want to listen for 375*0Sstevel@tonic-gate * responses from more than one server. 376*0Sstevel@tonic-gate */ 377*0Sstevel@tonic-gate if (connected) { 378*0Sstevel@tonic-gate (void) connect(s, &no_addr, 379*0Sstevel@tonic-gate sizeof (no_addr)); 380*0Sstevel@tonic-gate connected = 0; 381*0Sstevel@tonic-gate } 382*0Sstevel@tonic-gate #endif BSD 383*0Sstevel@tonic-gate if (sendto(s, buf, buflen, 0, 384*0Sstevel@tonic-gate (struct sockaddr *) &_res.nsaddr_list[ns], 385*0Sstevel@tonic-gate sizeof (struct sockaddr)) != buflen) { 386*0Sstevel@tonic-gate #ifdef DEBUG 387*0Sstevel@tonic-gate if (_res.options & RES_DEBUG) 388*0Sstevel@tonic-gate perror("sendto"); 389*0Sstevel@tonic-gate #endif DEBUG 390*0Sstevel@tonic-gate continue; 391*0Sstevel@tonic-gate } 392*0Sstevel@tonic-gate #if BSD >= 43 393*0Sstevel@tonic-gate } 394*0Sstevel@tonic-gate #endif 395*0Sstevel@tonic-gate 396*0Sstevel@tonic-gate /* 397*0Sstevel@tonic-gate * Wait for reply 398*0Sstevel@tonic-gate */ 399*0Sstevel@tonic-gate timeout.tv_sec = (_res.retrans << try); 400*0Sstevel@tonic-gate if (try > 0) 401*0Sstevel@tonic-gate timeout.tv_sec /= _res.nscount; 402*0Sstevel@tonic-gate if (timeout.tv_sec <= 0) 403*0Sstevel@tonic-gate timeout.tv_sec = 1; 404*0Sstevel@tonic-gate timeout.tv_usec = 0; 405*0Sstevel@tonic-gate wait: 406*0Sstevel@tonic-gate FD_ZERO(&dsmask); 407*0Sstevel@tonic-gate FD_SET(s, &dsmask); 408*0Sstevel@tonic-gate n = select(s+1, &dsmask, (fd_set *)NULL, 409*0Sstevel@tonic-gate (fd_set *)NULL, &timeout); 410*0Sstevel@tonic-gate if (n < 0) { 411*0Sstevel@tonic-gate #ifdef DEBUG 412*0Sstevel@tonic-gate if (_res.options & RES_DEBUG) 413*0Sstevel@tonic-gate perror("select"); 414*0Sstevel@tonic-gate #endif DEBUG 415*0Sstevel@tonic-gate continue; 416*0Sstevel@tonic-gate } 417*0Sstevel@tonic-gate if (n == 0) { 418*0Sstevel@tonic-gate /* 419*0Sstevel@tonic-gate * timeout 420*0Sstevel@tonic-gate */ 421*0Sstevel@tonic-gate #ifdef DEBUG 422*0Sstevel@tonic-gate if (_res.options & RES_DEBUG) 423*0Sstevel@tonic-gate printf("timeout\n"); 424*0Sstevel@tonic-gate #endif DEBUG 425*0Sstevel@tonic-gate #if BSD >= 43 426*0Sstevel@tonic-gate gotsomewhere = 1; 427*0Sstevel@tonic-gate #endif 428*0Sstevel@tonic-gate continue; 429*0Sstevel@tonic-gate } 430*0Sstevel@tonic-gate if ((resplen = recv(s, answer, anslen, 0)) 431*0Sstevel@tonic-gate <= 0) { 432*0Sstevel@tonic-gate #ifdef DEBUG 433*0Sstevel@tonic-gate if (_res.options & RES_DEBUG) 434*0Sstevel@tonic-gate perror("recvfrom"); 435*0Sstevel@tonic-gate #endif DEBUG 436*0Sstevel@tonic-gate continue; 437*0Sstevel@tonic-gate } 438*0Sstevel@tonic-gate gotsomewhere = 1; 439*0Sstevel@tonic-gate if (id != anhp->id) { 440*0Sstevel@tonic-gate /* 441*0Sstevel@tonic-gate * response from old query, ignore it 442*0Sstevel@tonic-gate */ 443*0Sstevel@tonic-gate #ifdef DEBUG 444*0Sstevel@tonic-gate if (_res.options & RES_DEBUG) { 445*0Sstevel@tonic-gate printf("old answer:\n"); 446*0Sstevel@tonic-gate p_query(answer); 447*0Sstevel@tonic-gate } 448*0Sstevel@tonic-gate #endif DEBUG 449*0Sstevel@tonic-gate goto wait; 450*0Sstevel@tonic-gate } 451*0Sstevel@tonic-gate if (!(_res.options & RES_IGNTC) && anhp->tc) { 452*0Sstevel@tonic-gate /* 453*0Sstevel@tonic-gate * get rest of answer; 454*0Sstevel@tonic-gate * use TCP with same server. 455*0Sstevel@tonic-gate */ 456*0Sstevel@tonic-gate #ifdef DEBUG 457*0Sstevel@tonic-gate if (_res.options & RES_DEBUG) 458*0Sstevel@tonic-gate printf("truncated answer\n"); 459*0Sstevel@tonic-gate #endif DEBUG 460*0Sstevel@tonic-gate (void) close(s); 461*0Sstevel@tonic-gate s = -1; 462*0Sstevel@tonic-gate v_circuit = 1; 463*0Sstevel@tonic-gate goto usevc; 464*0Sstevel@tonic-gate } 465*0Sstevel@tonic-gate } 466*0Sstevel@tonic-gate #ifdef DEBUG 467*0Sstevel@tonic-gate if (_res.options & RES_DEBUG) { 468*0Sstevel@tonic-gate printf("got answer:\n"); 469*0Sstevel@tonic-gate p_query(answer); 470*0Sstevel@tonic-gate } 471*0Sstevel@tonic-gate #endif DEBUG 472*0Sstevel@tonic-gate /* 473*0Sstevel@tonic-gate * If using virtual circuits, we assume that the first server 474*0Sstevel@tonic-gate * is preferred * over the rest (i.e. it is on the local 475*0Sstevel@tonic-gate * machine) and only keep that one open. 476*0Sstevel@tonic-gate * If we have temporarily opened a virtual circuit, 477*0Sstevel@tonic-gate * or if we haven't been asked to keep a socket open, 478*0Sstevel@tonic-gate * close the socket. 479*0Sstevel@tonic-gate */ 480*0Sstevel@tonic-gate if ((v_circuit && 481*0Sstevel@tonic-gate ((_res.options & RES_USEVC) == 0 || ns != 0)) || 482*0Sstevel@tonic-gate (_res.options & RES_STAYOPEN) == 0) { 483*0Sstevel@tonic-gate (void) close(s); 484*0Sstevel@tonic-gate s = -1; 485*0Sstevel@tonic-gate } 486*0Sstevel@tonic-gate return (resplen); 487*0Sstevel@tonic-gate } 488*0Sstevel@tonic-gate } 489*0Sstevel@tonic-gate if (s >= 0) { 490*0Sstevel@tonic-gate (void) close(s); 491*0Sstevel@tonic-gate s = -1; 492*0Sstevel@tonic-gate } 493*0Sstevel@tonic-gate if (v_circuit == 0) 494*0Sstevel@tonic-gate if (gotsomewhere == 0) 495*0Sstevel@tonic-gate errno = ECONNREFUSED; /* no nameservers found */ 496*0Sstevel@tonic-gate else 497*0Sstevel@tonic-gate errno = ETIMEDOUT; /* no answer obtained */ 498*0Sstevel@tonic-gate else 499*0Sstevel@tonic-gate errno = terrno; 500*0Sstevel@tonic-gate return (-1); 501*0Sstevel@tonic-gate } 502*0Sstevel@tonic-gate 503*0Sstevel@tonic-gate /* 504*0Sstevel@tonic-gate * This routine is for closing the socket if a virtual circuit is used and 505*0Sstevel@tonic-gate * the program wants to close it. This provides support for endhostent() 506*0Sstevel@tonic-gate * which expects to close the socket. 507*0Sstevel@tonic-gate * 508*0Sstevel@tonic-gate * This routine is not expected to be user visible. 509*0Sstevel@tonic-gate */ 510*0Sstevel@tonic-gate _res_close() 511*0Sstevel@tonic-gate { 512*0Sstevel@tonic-gate if (s != -1) { 513*0Sstevel@tonic-gate (void) close(s); 514*0Sstevel@tonic-gate s = -1; 515*0Sstevel@tonic-gate } 516*0Sstevel@tonic-gate } 517