OpenSolaris Launch

1 files changed, 516 insertions, 0 deletions

diff --git a/usr/src/lib/libresolv/res_send.c b/usr/src/lib/libresolv/res_send.c
new file mode 100644
index 0000000000..89a602f6d2
--- /dev/null
+++ b/usr/src/lib/libresolv/res_send.c
@@ -0,0 +1,516 @@
+/*
+ * CDDL HEADER START
+ *
+ * The contents of this file are subject to the terms of the
+ * Common Development and Distribution License, Version 1.0 only
+ * (the "License").  You may not use this file except in compliance
+ * with the License.
+ *
+ * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
+ * or http://www.opensolaris.org/os/licensing.
+ * See the License for the specific language governing permissions
+ * and limitations under the License.
+ *
+ * When distributing Covered Code, include this CDDL HEADER in each
+ * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
+ * If applicable, add the following below this CDDL HEADER, with the
+ * fields enclosed by brackets "[]" replaced with your own identifying
+ * information: Portions Copyright [yyyy] [name of copyright owner]
+ *
+ * CDDL HEADER END
+ */
+/*
+ * Copyright 2003 Sun Microsystems, Inc.  All rights reserved.
+ * Use is subject to license terms.
+ */
+
+/*	Copyright (c) 1984, 1986, 1987, 1988, 1989 AT&T	*/
+/*	  All Rights Reserved  	*/
+
+/*
+ * University Copyright- Copyright (c) 1982, 1986, 1988
+ * The Regents of the University of California
+ * All Rights Reserved
+ *
+ * University Acknowledgment- Portions of this document are derived from
+ * software developed by the University of California, Berkeley, and its
+ * contributors.
+ */
+
+#pragma ident	"%Z%%M%	%I%	%E% SMI"
+
+/*
+ * Send query to name server and wait for reply.
+ */
+
+#include "synonyms.h"
+
+#include <sys/param.h>
+#include <sys/time.h>
+#include <sys/socket.h>
+#include <sys/uio.h>
+#include <sys/stat.h>
+#include <netinet/in.h>
+#include <stdio.h>
+#include <errno.h>
+#include <arpa/nameser.h>
+#include <resolv.h>
+
+
+static int s = -1;	/* socket used for communications */
+static struct sockaddr no_addr;
+
+
+#ifndef FD_SET
+#define	NFDBITS		32
+#define	FD_SETSIZE	32
+#define	FD_SET(n, p)	((p)->fds_bits[(n)/NFDBITS] |= (1 << ((n) % NFDBITS)))
+#define	FD_CLR(n, p)	((p)->fds_bits[(n)/NFDBITS] &= ~(1 << ((n) % NFDBITS)))
+#define	FD_ISSET(n, p)	((p)->fds_bits[(n)/NFDBITS] & (1 << ((n) % NFDBITS)))
+#ifdef SYSV
+#define	FD_ZERO(p)	memset((void *)(p), 0, sizeof (*(p)))
+#else
+#define	FD_ZERO(p)	bzero((char *)(p), sizeof (*(p)))
+#endif
+#endif
+
+/*
+ * 1247019: Kludge to time out quickly if there is no /etc/resolv.conf
+ * and a TCP connection to the local DNS server fails.
+ */
+
+static int _confcheck()
+{
+	int ns;
+	struct stat rc_stat;
+	struct sockaddr_in ns_sin;
+
+
+	/* First, we check to see if /etc/resolv.conf exists.
+	 * If it doesn't, then localhost is mostlikely to be
+	 * the nameserver.
+	 */
+	if (stat(_PATH_RESCONF, &rc_stat) == -1 && errno == ENOENT) {
+
+		/* Next, we check to see if _res.nsaddr is set to loopback.
+		 * If it isn't, it has been altered by the application
+		 * explicitly and we then want to bail with success.
+		 */
+		if (_res.nsaddr.sin_addr.S_un.S_addr == htonl(INADDR_LOOPBACK)) {
+
+			/* Lastly, we try to connect to the TCP port of the
+			 * nameserver.  If this fails, then we know that
+			 * DNS is misconfigured and we can quickly exit.
+			 */
+			ns = socket(AF_INET, SOCK_STREAM, 0);
+			IN_SET_LOOPBACK_ADDR(&ns_sin);
+			ns_sin.sin_port = htons(NAMESERVER_PORT);
+			if (connect(ns, (struct sockaddr *) &ns_sin,
+				    sizeof ns_sin) == -1) {
+				close(ns);
+				return(-1);
+			}
+			else {
+				close(ns);
+				return(0);
+			}
+		}
+	
+		return(0);
+	}
+	
+	return (0);
+}
+
+res_send(buf, buflen, answer, anslen)
+	char *buf;
+	int buflen;
+	char *answer;
+	int anslen;
+{
+	register int n;
+	int try, v_circuit, resplen, ns;
+	int gotsomewhere = 0, connected = 0;
+	int connreset = 0;
+	u_short id, len;
+	char *cp;
+	fd_set dsmask;
+	struct timeval timeout;
+	HEADER *hp = (HEADER *) buf;
+	HEADER *anhp = (HEADER *) answer;
+	struct iovec iov[2];
+	int terrno = ETIMEDOUT;
+	char junk[512];
+
+#ifdef DEBUG
+	if (_res.options & RES_DEBUG) {
+		printf("res_send()\n");
+		p_query(buf);
+	}
+#endif DEBUG
+	if (!(_res.options & RES_INIT))
+		if (res_init() == -1) {
+			return (-1);
+		}
+
+	/* 1247019: Check to see if we can bailout quickly. */
+	if (_confcheck() == -1)
+	    return(-1);
+
+	v_circuit = (_res.options & RES_USEVC) || buflen > PACKETSZ;
+	id = hp->id;
+	/*
+	 * Send request, RETRY times, or until successful
+	 */
+	for (try = 0; try < _res.retry; try++) {
+		for (ns = 0; ns < _res.nscount; ns++) {
+#ifdef DEBUG
+			if (_res.options & RES_DEBUG)
+				printf("Querying server (# %d) address = %s\n",
+				ns+1, inet_ntoa(_res.nsaddr_list[ns].sin_addr));
+#endif DEBUG
+		usevc:
+			if (v_circuit) {
+				int truncated = 0;
+
+				/*
+				 * Use virtual circuit;
+				 * at most one attempt per server.
+				 */
+				try = _res.retry;
+				if (s < 0) {
+					s = _socket(AF_INET, SOCK_STREAM, 0);
+					if (s < 0) {
+						terrno = errno;
+#ifdef DEBUG
+						if (_res.options & RES_DEBUG) {
+						perror("socket (vc) failed");
+						}
+#endif DEBUG
+						continue;
+					}
+					if (connect(s, (struct sockaddr *) &_res.nsaddr_list[ns],
+						sizeof (struct sockaddr)) < 0) {
+						terrno = errno;
+#ifdef DEBUG
+						if (_res.options & RES_DEBUG) {
+						perror("connect failed");
+						}
+#endif DEBUG
+						(void) close(s);
+						s = -1;
+						continue;
+					}
+				}
+				/*
+				 * Send length & message
+				 */
+				len = htons((u_short)buflen);
+				iov[0].iov_base = (caddr_t)&len;
+				iov[0].iov_len = sizeof (len);
+				iov[1].iov_base = buf;
+				iov[1].iov_len = buflen;
+				if (writev(s, iov, 2) != sizeof (len) +
+								buflen) {
+					terrno = errno;
+#ifdef DEBUG
+					if (_res.options & RES_DEBUG)
+						perror("write failed");
+#endif DEBUG
+					(void) close(s);
+					s = -1;
+					continue;
+				}
+				/*
+				 * Receive length & response
+				 */
+				cp = answer;
+				len = sizeof (short);
+				while (len != 0 && (n = read
+					(s, (char *)cp, (int)len)) > 0) {
+					cp += n;
+					len -= n;
+				}
+				if (n <= 0) {
+					terrno = errno;
+#ifdef DEBUG
+					if (_res.options & RES_DEBUG)
+						perror("read failed");
+#endif DEBUG
+					(void) close(s);
+					s = -1;
+				/*
+				 * A long running process might get its TCP
+				 * connection reset if the remote server was
+				 * restarted.  Requery the server instead of
+				 * trying a new one.  When there is only one
+				 * server, this means that a query might work
+				 * instead of failing.  We only allow one reset
+				 * per query to prevent looping.
+				 */
+					if (terrno == ECONNRESET &&
+							!connreset) {
+						connreset = 1;
+						ns--;
+					}
+					continue;
+				}
+				cp = answer;
+				if ((resplen = ntohs(*(u_short *)cp)) >
+								anslen) {
+#ifdef DEBUG
+					if (_res.options & RES_DEBUG)
+						fprintf(stderr,
+							"response truncated\n");
+#endif DEBUG
+					len = anslen;
+					truncated = 1;
+				} else
+					len = resplen;
+				while (len != 0 &&
+					(n = read(s, (char *)cp,
+							(int)len)) > 0) {
+					cp += n;
+					len -= n;
+				}
+				if (n <= 0) {
+					terrno = errno;
+#ifdef DEBUG
+					if (_res.options & RES_DEBUG)
+						perror("read failed");
+#endif DEBUG
+					(void) close(s);
+					s = -1;
+					continue;
+				}
+				if (truncated) {
+					/*
+					 * Flush rest of answer
+					 * so connection stays in synch.
+					 */
+					anhp->tc = 1;
+					len = resplen - anslen;
+					/*
+					 * set the value of resplen to anslen,
+					 * this is done because the caller
+					 * assumes resplen contains the size of
+					 * message read into the "answer" buffer
+					 * passed in.
+					 */
+					resplen = anslen;
+
+					while (len != 0) {
+						n = (len > sizeof (junk) ?
+							sizeof (junk) : len);
+						if ((n = read(s, junk, n)) > 0)
+							len -= n;
+						else
+							break;
+					}
+				}
+			} else {
+				/*
+				 * Use datagrams.
+				 */
+				if (s < 0) {
+					s = _socket(AF_INET, SOCK_DGRAM, 0);
+					if (s < 0) {
+						terrno = errno;
+#ifdef DEBUG
+						if (_res.options & RES_DEBUG) {
+						perror("socket (dg) failed");
+						}
+#endif DEBUG
+						continue;
+					}
+				}
+#if	BSD >= 43
+			/*
+			 * I'm tired of answering this question, so:
+			 * On a 4.3BSD+ machine (client and server,
+			 * actually), sending to a nameserver datagram
+			 * port with no nameserver will cause an
+			 * ICMP port unreachable message to be returned.
+			 * If our datagram socket is "connected" to the
+			 * server, we get an ECONNREFUSED error on the next
+			 * socket operation, and select returns if the
+			 * error message is received.  We can thus detect
+			 * the absence of a nameserver without timing out.
+			 * If we have sent queries to at least two servers,
+			 * however, we don't want to remain connected,
+			 * as we wish to receive answers from the first
+			 * server to respond.
+			 */
+				if (_res.nscount == 1 ||
+						(try == 0 && ns == 0)) {
+					/*
+					 * Don't use connect if we might
+					 * still receive a response
+					 * from another server.
+					 */
+					if (connected == 0) {
+						if (connect(s,
+						(struct sockaddr *) &_res.nsaddr_list[ns],
+						sizeof (struct sockaddr)) < 0) {
+#ifdef DEBUG
+							if (_res.options &
+								RES_DEBUG) {
+							perror("connect");
+							}
+#endif DEBUG
+							continue;
+						}
+						connected = 1;
+					}
+					if (send(s, buf, buflen, 0) != buflen) {
+#ifdef DEBUG
+						if (_res.options & RES_DEBUG)
+							perror("send");
+#endif DEBUG
+						continue;
+					}
+				} else {
+					/*
+					 * Disconnect if we want to listen for
+					 * responses from more than one server.
+					 */
+					if (connected) {
+						(void) connect(s, &no_addr,
+							sizeof (no_addr));
+						connected = 0;
+					}
+#endif BSD
+					if (sendto(s, buf, buflen, 0,
+						(struct sockaddr *) &_res.nsaddr_list[ns],
+					sizeof (struct sockaddr)) != buflen) {
+#ifdef DEBUG
+						if (_res.options & RES_DEBUG)
+							perror("sendto");
+#endif DEBUG
+						continue;
+					}
+#if	BSD >= 43
+				}
+#endif
+
+				/*
+				 * Wait for reply
+				 */
+				timeout.tv_sec = (_res.retrans << try);
+				if (try > 0)
+					timeout.tv_sec /= _res.nscount;
+				if (timeout.tv_sec <= 0)
+					timeout.tv_sec = 1;
+				timeout.tv_usec = 0;
+wait:
+				FD_ZERO(&dsmask);
+				FD_SET(s, &dsmask);
+				n = select(s+1, &dsmask, (fd_set *)NULL,
+						(fd_set *)NULL, &timeout);
+				if (n < 0) {
+#ifdef DEBUG
+					if (_res.options & RES_DEBUG)
+						perror("select");
+#endif DEBUG
+					continue;
+				}
+				if (n == 0) {
+					/*
+					 * timeout
+					 */
+#ifdef DEBUG
+					if (_res.options & RES_DEBUG)
+						printf("timeout\n");
+#endif DEBUG
+#if BSD >= 43
+					gotsomewhere = 1;
+#endif
+					continue;
+				}
+				if ((resplen = recv(s, answer, anslen, 0))
+									<= 0) {
+#ifdef DEBUG
+					if (_res.options & RES_DEBUG)
+						perror("recvfrom");
+#endif DEBUG
+					continue;
+				}
+				gotsomewhere = 1;
+				if (id != anhp->id) {
+					/*
+					 * response from old query, ignore it
+					 */
+#ifdef DEBUG
+					if (_res.options & RES_DEBUG) {
+						printf("old answer:\n");
+						p_query(answer);
+					}
+#endif DEBUG
+					goto wait;
+				}
+				if (!(_res.options & RES_IGNTC) && anhp->tc) {
+					/*
+					 * get rest of answer;
+					 * use TCP with same server.
+					 */
+#ifdef DEBUG
+					if (_res.options & RES_DEBUG)
+						printf("truncated answer\n");
+#endif DEBUG
+					(void) close(s);
+					s = -1;
+					v_circuit = 1;
+					goto usevc;
+				}
+			}
+#ifdef DEBUG
+			if (_res.options & RES_DEBUG) {
+				printf("got answer:\n");
+				p_query(answer);
+			}
+#endif DEBUG
+		/*
+		 * If using virtual circuits, we assume that the first server
+		 * is preferred * over the rest (i.e. it is on the local
+		 * machine) and only keep that one open.
+		 * If we have temporarily opened a virtual circuit,
+		 * or if we haven't been asked to keep a socket open,
+		 * close the socket.
+		 */
+			if ((v_circuit &&
+				((_res.options & RES_USEVC) == 0 || ns != 0)) ||
+				(_res.options & RES_STAYOPEN) == 0) {
+				(void) close(s);
+				s = -1;
+			}
+			return (resplen);
+		}
+	}
+	if (s >= 0) {
+		(void) close(s);
+		s = -1;
+	}
+	if (v_circuit == 0)
+		if (gotsomewhere == 0)
+			errno = ECONNREFUSED;	/* no nameservers found */
+		else
+			errno = ETIMEDOUT;	/* no answer obtained */
+	else
+		errno = terrno;
+	return (-1);
+}
+
+/*
+ * This routine is for closing the socket if a virtual circuit is used and
+ * the program wants to close it.  This provides support for endhostent()
+ * which expects to close the socket.
+ *
+ * This routine is not expected to be user visible.
+ */
+_res_close()
+{
+	if (s != -1) {
+		(void) close(s);
+		s = -1;
+	}
+}