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/*
* Copyright (c) 1985, 1989 Regents of the University of California.
* All rights reserved.
*
* Redistribution and use in source and binary forms are permitted
* provided that: (1) source distributions retain this entire copyright
* notice and comment, and (2) distributions including binaries display
* the following acknowledgement: ``This product includes software
* developed by the University of California, Berkeley and its contributors''
* in the documentation or other materials provided with the distribution
* and in all advertising materials mentioning features or use of this
* software. Neither the name of the University nor the names of its
* contributors may be used to endorse or promote products derived
* from this software without specific prior written permission.
* THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
*/
#ifndef lint
static char Version[] = "@(#)send.c e07@nikhef.nl (Eric Wassenaar) 951231";
#endif
#if defined(apollo) && defined(lint)
#define __attribute(x)
#endif
#include <stdio.h>
#include <errno.h>
#include <setjmp.h>
#include <signal.h>
#include <sys/time.h>
#include <sys/types.h> /* not always automatically included */
#include <sys/param.h>
#include <sys/socket.h>
#include <netinet/in.h>
#undef NOERROR /* in <sys/streams.h> on solaris 2.x */
#include <arpa/nameser.h>
#include <resolv.h>
#include "port.h" /* various portability definitions */
#include "conf.h" /* various configuration definitions */
#define input /* read-only input parameter */
#define output /* modified output parameter */
#define bitset(a,b) (((a) & (b)) != 0)
#define setalarm(n) (void) alarm((unsigned int)n)
extern int errno;
extern res_state_t _res; /* defined in res_init.c */
char *dbprefix = DBPREFIX; /* prefix for debug messages to stdout */
static int timeout; /* connection read timeout */
static struct sockaddr_in from; /* address of inbound packet */
static struct sockaddr *from_sa = (struct sockaddr *)&from;
/* extern */
char *inet_ntoa PROTO((struct in_addr));
/* send.c */
#ifdef HOST_RES_SEND
int res_send PROTO((CONST qbuf_t *, int, qbuf_t *, int));
void _res_close PROTO((void));
static int send_stream PROTO((struct sockaddr_in *, qbuf_t *, int, qbuf_t *, int));
static int send_dgram PROTO((struct sockaddr_in *, qbuf_t *, int, qbuf_t *, int));
#endif /*HOST_RES_SEND*/
static sigtype_t timer PROTO((int));
int _res_connect PROTO((int, struct sockaddr_in *, int));
int _res_write PROTO((int, struct sockaddr_in *, char *, char *, int));
int _res_read PROTO((int, struct sockaddr_in *, char *, char *, int));
static int recv_sock PROTO((int, char *, int));
void _res_perror PROTO((struct sockaddr_in *, char *, char *));
#ifdef HOST_RES_SEND
/*
** RES_SEND -- Send nameserver query and retrieve answer
** -----------------------------------------------------
**
** Returns:
** Length of nameserver answer buffer, if obtained.
** -1 if an error occurred (errno set appropriately).
**
** This is a simplified version of the BIND 4.8.3 res_send().
** - Always use connected datagrams to get proper error messages.
** - Do not only return ETIMEDOUT or ECONNREFUSED in datagram mode,
** but also host or network unreachable status if appropriate.
** - Never leave a connection open after we got an answer.
** - No special ECONNRESET handling when using virtual circuits.
**
** Note that this private version of res_send() is not only called
** directly by 'host' but also indirectly by gethostbyname() or by
** gethostbyaddr() via their resolver interface routines.
*/
int
res_send(query, querylen, answer, anslen)
input CONST qbuf_t *query; /* location of formatted query buffer */
input int querylen; /* length of query buffer */
output qbuf_t *answer; /* location of buffer to store answer */
input int anslen; /* maximum size of answer buffer */
{
HEADER *bp = (HEADER *)answer;
struct sockaddr_in *addr; /* the server address to connect to */
int v_circuit; /* virtual circuit or datagram switch */
int servfail[MAXNS]; /* saved failure codes per nameserver */
register int try, ns;
register int n;
/* make sure resolver has been initialized */
if (!bitset(RES_INIT, _res.options) && res_init() == -1)
return(-1);
if (bitset(RES_DEBUG, _res.options))
{
printf("%sres_send()\n", dbprefix);
pr_query(query, querylen, stdout);
}
/* use virtual circuit if requested or if necessary */
v_circuit = bitset(RES_USEVC, _res.options) || (querylen > PACKETSZ);
/* reset server failure codes */
for (n = 0; n < MAXNS; n++)
servfail[n] = 0;
/*
* Do _res.retry attempts for each of the _res.nscount addresses.
* Upon failure, the current server will be marked bad if we got
* an error condition which makes it unlikely that we will succeed
* the next time we try this server.
* Internal operating system failures, such as temporary lack of
* resources, do not fall in that category.
*/
for (try = 0; try < _res.retry; try++)
{
for (ns = 0; ns < _res.nscount; ns++)
{
/* skip retry if server failed permanently */
if (servfail[ns])
continue;
/* fetch server address */
addr = &nslist(ns);
retry:
if (bitset(RES_DEBUG, _res.options))
printf("%sQuerying server (# %d) %s address = %s\n", dbprefix,
ns+1, v_circuit ? "tcp" : "udp", inet_ntoa(addr->sin_addr));
if (v_circuit)
{
/* at most one attempt per server */
try = _res.retry;
/* connect via virtual circuit */
n = send_stream(addr, query, querylen, answer, anslen);
}
else
{
/* set datagram read timeout for recv_sock() */
timeout = (_res.retrans << try);
if (try > 0)
timeout /= _res.nscount;
if (timeout <= 0)
timeout = 1;
/* connect via datagram */
n = send_dgram(addr, query, querylen, answer, anslen);
/* check truncation; use v_circuit with same server */
if (n > 0 && bp->tc)
{
if (bitset(RES_DEBUG, _res.options))
printf("%struncated answer\n", dbprefix);
if (!bitset(RES_IGNTC, _res.options))
{
v_circuit = 1;
goto retry;
}
}
}
if (n <= 0)
{
switch (errno)
{
case ECONNREFUSED:
case ENETDOWN:
case ENETUNREACH:
case EHOSTDOWN:
case EHOSTUNREACH:
servfail[ns] = errno;
break;
}
/* try next server */
continue;
}
if (bitset(RES_DEBUG, _res.options))
{
printf("%sgot answer, %d bytes:\n", dbprefix, n);
pr_query(answer, n, stdout);
}
/* we have an answer; clear possible error condition */
errno = 0;
return(n);
}
}
/* no answer obtained; return error condition */
return(-1);
}
/*
** _RES_CLOSE -- Close an open stream or dgram connection
** ------------------------------------------------------
**
** Returns:
** None.
*/
static int srvsock = -1; /* socket descriptor */
void
_res_close()
{
int save_errno = errno; /* preserve state */
/* close the connection if open */
if (srvsock >= 0)
{
(void) close(srvsock);
srvsock = -1;
}
/* restore state */
errno = save_errno;
}
/*
** SEND_STREAM -- Query nameserver via virtual circuit
** ---------------------------------------------------
**
** Returns:
** Length of nameserver answer buffer, if obtained.
** -1 if an error occurred.
**
** Note that connect() is the call that is allowed to fail
** under normal circumstances. All other failures generate
** an unconditional error message.
** Note that truncation is handled within _res_read().
*/
static int
send_stream(addr, query, querylen, answer, anslen)
input struct sockaddr_in *addr; /* the server address to connect to */
input qbuf_t *query; /* location of formatted query buffer */
input int querylen; /* length of query buffer */
output qbuf_t *answer; /* location of buffer to store answer */
input int anslen; /* maximum size of answer buffer */
{
char *host = NULL; /* name of server is unknown */
register int n;
/*
* Setup a virtual circuit connection.
*/
srvsock = socket(AF_INET, SOCK_STREAM, 0);
if (srvsock < 0)
{
_res_perror(addr, host, "socket");
return(-1);
}
if (_res_connect(srvsock, addr, sizeof(*addr)) < 0)
{
if (bitset(RES_DEBUG, _res.options))
_res_perror(addr, host, "connect");
_res_close();
return(-1);
}
if (bitset(RES_DEBUG, _res.options))
printf("%sconnected to %s\n", dbprefix, inet_ntoa(addr->sin_addr));
/*
* Send the query buffer.
*/
if (_res_write(srvsock, addr, host, (char *)query, querylen) < 0)
{
_res_close();
return(-1);
}
/*
* Read the answer buffer.
*/
n = _res_read(srvsock, addr, host, (char *)answer, anslen);
if (n <= 0)
{
_res_close();
return(-1);
}
/*
* Never leave the socket open.
*/
_res_close();
return(n);
}
/*
** SEND_DGRAM -- Query nameserver via datagram
** -------------------------------------------
**
** Returns:
** Length of nameserver answer buffer, if obtained.
** -1 if an error occurred.
**
** Inputs:
** The global variable ``timeout'' should have been
** set with the desired timeout value in seconds.
**
** Sending to a nameserver datagram port with no nameserver running
** will cause an ICMP port unreachable message to be returned. If the
** socket is connected, we get an ECONNREFUSED error on the next socket
** operation, and select returns if the error message is received.
** Also, we get ENETUNREACH or EHOSTUNREACH errors if appropriate.
** We thus get a proper error status before timing out.
** This method usually works only if BSD >= 43.
**
** Note that send() and recvfrom() are now the calls that are allowed
** to fail under normal circumstances. All other failures generate
** an unconditional error message.
*/
static int
send_dgram(addr, query, querylen, answer, anslen)
input struct sockaddr_in *addr; /* the server address to connect to */
input qbuf_t *query; /* location of formatted query buffer */
input int querylen; /* length of query buffer */
output qbuf_t *answer; /* location of buffer to store answer */
input int anslen; /* maximum size of answer buffer */
{
char *host = NULL; /* name of server is unknown */
HEADER *qp = (HEADER *)query;
HEADER *bp = (HEADER *)answer;
register int n;
/*
* Setup a connected datagram socket.
*/
srvsock = socket(AF_INET, SOCK_DGRAM, 0);
if (srvsock < 0)
{
_res_perror(addr, host, "socket");
return(-1);
}
if (connect(srvsock, (struct sockaddr *)addr, sizeof(*addr)) < 0)
{
_res_perror(addr, host, "connect");
_res_close();
return(-1);
}
/*
* Send the query buffer.
*/
if (send(srvsock, (char *)query, querylen, 0) != querylen)
{
if (bitset(RES_DEBUG, _res.options))
_res_perror(addr, host, "send");
_res_close();
return(-1);
}
/*
* Wait for the arrival of a reply, timeout, or error message.
*/
wait:
n = recv_sock(srvsock, (char *)answer, anslen);
if (n <= 0)
{
if (bitset(RES_DEBUG, _res.options))
_res_perror(addr, host, "recvfrom");
_res_close();
return(-1);
}
/*
* Make sure it is the proper response by checking the packet id.
*/
if (qp->id != bp->id)
{
if (bitset(RES_DEBUG, _res.options))
{
printf("%sold answer:\n", dbprefix);
pr_query(answer, n, stdout);
}
goto wait;
}
/*
* Never leave the socket open.
*/
_res_close();
return(n);
}
#endif /*HOST_RES_SEND*/
/*
** _RES_CONNECT -- Connect to a stream (virtual circuit) socket
** ------------------------------------------------------------
**
** Returns:
** 0 if successfully connected.
** -1 in case of failure or timeout.
**
** Note that we use _res.retrans to override the default
** connect timeout value.
*/
static jmp_buf timer_buf;
static sigtype_t
/*ARGSUSED*/
timer(sig)
int sig;
{
longjmp(timer_buf, 1);
/*NOTREACHED*/
}
int
_res_connect(sock, addr, addrlen)
input int sock;
input struct sockaddr_in *addr; /* the server address to connect to */
input int addrlen;
{
if (setjmp(timer_buf) != 0)
{
errno = ETIMEDOUT;
setalarm(0);
return(-1);
}
(void) signal(SIGALRM, timer);
setalarm(_res.retrans);
if (connect(sock, (struct sockaddr *)addr, addrlen) < 0)
{
if (errno == EINTR)
errno = ETIMEDOUT;
setalarm(0);
return(-1);
}
setalarm(0);
return(0);
}
/*
** _RES_WRITE -- Write the query buffer via a stream socket
** --------------------------------------------------------
**
** Returns:
** Length of buffer if successfully transmitted.
** -1 in case of failure (error message is issued).
**
** The query is sent in two steps: first a single word with
** the length of the buffer, followed by the buffer itself.
*/
int
_res_write(sock, addr, host, buf, bufsize)
input int sock;
input struct sockaddr_in *addr; /* the server address to connect to */
input char *host; /* name of server to connect to */
input char *buf; /* location of formatted query buffer */
input int bufsize; /* length of query buffer */
{
u_short len;
/*
* Write the length of the query buffer.
*/
/* len = htons(bufsize); */
putshort((u_short)bufsize, (u_char *)&len);
if (write(sock, (char *)&len, INT16SZ) != INT16SZ)
{
_res_perror(addr, host, "write query length");
return(-1);
}
/*
* Write the query buffer itself.
*/
if (write(sock, buf, bufsize) != bufsize)
{
_res_perror(addr, host, "write query");
return(-1);
}
return(bufsize);
}
/*
** _RES_READ -- Read the answer buffer via a stream socket
** -------------------------------------------------------
**
** Returns:
** Length of buffer if successfully received.
** -1 in case of failure (error message is issued).
**
** The answer is read in two steps: first a single word which
** gives the length of the buffer, followed by the buffer itself.
** If the answer is too long to fit into the supplied buffer,
** only the portion that fits will be stored, the residu will be
** flushed, and the truncation flag will be set.
*/
int
_res_read(sock, addr, host, buf, bufsize)
input int sock;
input struct sockaddr_in *addr; /* the server address to connect to */
input char *host; /* name of server to connect to */
output char *buf; /* location of buffer to store answer */
input int bufsize; /* maximum size of answer buffer */
{
u_short len;
char *buffer;
int buflen;
int reslen;
register int n;
/* set stream timeout for recv_sock() */
timeout = 60;
/*
* Read the length of answer buffer.
*/
buffer = (char *)&len;
buflen = INT16SZ;
while (buflen > 0 && (n = recv_sock(sock, buffer, buflen)) > 0)
{
buffer += n;
buflen -= n;
}
if (buflen != 0)
{
_res_perror(addr, host, "read answer length");
return(-1);
}
/*
* Terminate if length is zero.
*/
/* len = ntohs(len); */
len = _getshort((u_char *)&len);
if (len == 0)
return(0);
/*
* Check for truncation.
*/
reslen = 0;
if ((int)len > bufsize)
{
reslen = len - bufsize;
len = bufsize;
}
/*
* Read the answer buffer itself.
*/
buffer = buf;
buflen = len;
while (buflen > 0 && (n = recv_sock(sock, buffer, buflen)) > 0)
{
buffer += n;
buflen -= n;
}
if (buflen != 0)
{
_res_perror(addr, host, "read answer");
return(-1);
}
/*
* Discard the residu to keep connection in sync.
*/
if (reslen > 0)
{
HEADER *bp = (HEADER *)buf;
char resbuf[PACKETSZ];
buffer = resbuf;
buflen = reslen < sizeof(resbuf) ? reslen : sizeof(resbuf);
while (reslen > 0 && (n = recv_sock(sock, buffer, buflen)) > 0)
{
reslen -= n;
buflen = reslen < sizeof(resbuf) ? reslen : sizeof(resbuf);
}
if (reslen != 0)
{
_res_perror(addr, host, "read residu");
return(-1);
}
if (bitset(RES_DEBUG, _res.options))
printf("%sresponse truncated\n", dbprefix);
/* set truncation flag */
bp->tc = 1;
}
return(len);
}
/*
** RECV_SOCK -- Read from stream or datagram socket with timeout
** -------------------------------------------------------------
**
** Returns:
** Length of buffer if successfully received.
** -1 in case of failure or timeout.
**
** Inputs:
** The global variable ``timeout'' should have been
** set with the desired timeout value in seconds.
**
** Outputs:
** Sets global ``from'' to the address from which we
** received the packet.
*/
static int
recv_sock(sock, buffer, buflen)
input int sock;
output char *buffer; /* current buffer address */
input int buflen; /* remaining buffer size */
{
fd_set fds;
struct timeval wait;
int fromlen;
register int n;
wait.tv_sec = timeout;
wait.tv_usec = 0;
/* FD_ZERO(&fds); */
bzero((char *)&fds, sizeof(fds));
FD_SET(sock, &fds);
/* wait for the arrival of data, or timeout */
n = select(FD_SETSIZE, &fds, (fd_set *)NULL, (fd_set *)NULL, &wait);
if (n <= 0)
{
if (n == 0)
errno = ETIMEDOUT;
return(-1);
}
/* fake an error if nothing was actually read */
fromlen = sizeof(from);
n = recvfrom(sock, buffer, buflen, 0, from_sa, &fromlen);
if (n == 0)
errno = ECONNRESET;
return(n);
}
/*
* Alternative version for systems with broken networking code.
*
* The select() system call may fail on the solaris 2.4 platform
* without appropriate patches. However, these patches are reported
* to break client NFS.
*
* This version uses an alarm() instead of select(). This introduces
* additional system call overhead.
*/
#ifdef BROKEN_SELECT
static int
recv_sock(sock, buffer, buflen)
input int sock;
output char *buffer; /* current buffer address */
input int buflen; /* remaining buffer size */
{
int fromlen;
register int n;
if (setjmp(timer_buf) != 0)
{
errno = ETIMEDOUT;
setalarm(0);
return(-1);
}
(void) signal(SIGALRM, timer);
setalarm(timeout);
/* fake an error if nothing was actually read */
fromlen = sizeof(from);
n = recvfrom(sock, buffer, buflen, 0, from_sa, &fromlen);
if (n == 0)
errno = ECONNRESET;
setalarm(0);
return(n);
}
#endif /*BROKEN_SELECT*/
/*
** _RES_PERROR -- Issue perror message including host info
** -------------------------------------------------------
**
** Returns:
** None.
*/
void
_res_perror(addr, host, message)
input struct sockaddr_in *addr; /* the server address to connect to */
input char *host; /* name of server to connect to */
input char *message; /* perror message string */
{
int save_errno = errno; /* preserve state */
/* prepend server address and name */
if (addr != NULL)
(void) fprintf(stderr, "%s ", inet_ntoa(addr->sin_addr));
if (host != NULL)
(void) fprintf(stderr, "(%s) ", host);
/* issue actual message */
errno = save_errno;
perror(message);
/* restore state */
errno = save_errno;
}
These are the contents of the former NiCE NeXT User Group NeXTSTEP/OpenStep software archive, currently hosted by Netfuture.ch.