Minix2.0/src/lib/ip/res_send.c
/*
* Copyright (c) 1985, 1989 Regents of the University of California.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by the University of
* California, Berkeley and its contributors.
* 4. 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 BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#if defined(LIBC_SCCS) && !defined(lint)
static char sccsid[] = "@(#)res_send.c 6.27 (Berkeley) 2/24/91";
#endif /* LIBC_SCCS and not lint */
/*
* Send query to name server and wait for reply.
*/
#if !_MINIX
#include <sys/param.h>
#include <sys/time.h>
#include <sys/socket.h>
#include <sys/uio.h>
#include <netinet/in.h>
#include <arpa/nameser.h>
#include <stdio.h>
#include <errno.h>
#include <resolv.h>
#include <unistd.h>
#include <string.h>
#else /* _MINIX */
#include <sys/types.h>
#include <sys/ioctl.h>
#include <sys/stat.h>
#include <assert.h>
#include <errno.h>
#include <fcntl.h>
#include <signal.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <net/hton.h>
#include <net/netlib.h>
#include <net/gen/in.h>
#include <net/gen/inet.h>
#include <net/gen/netdb.h>
#include <net/gen/nameser.h>
#include <net/gen/resolv.h>
#include <net/gen/tcp.h>
#include <net/gen/tcp_io.h>
#include <net/gen/udp.h>
#include <net/gen/udp_hdr.h>
#include <net/gen/udp_io.h>
typedef u16_t u_short;
static int tcp_connect _ARGS(( ipaddr_t host, Tcpport_t port, int *terrno ));
static int tcpip_writeall _ARGS(( int fd, const char *buf, size_t siz ));
static int udp_connect _ARGS(( void ));
static int udp_sendto _ARGS(( int fd, const char *buf, unsigned buflen,
ipaddr_t addr, Udpport_t port ));
static int udp_receive _ARGS(( int fd, char *buf, unsigned buflen,
time_t timeout ));
static void alarm_handler _ARGS(( int sig ));
#endif /* !_MINIX */
static int s = -1; /* socket used for communications */
#if !_MINIX
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)))
#define FD_ZERO(p) bzero((char *)(p), sizeof(*(p)))
#endif /* FD_SET */
#endif /* _MINIX */
res_send(buf, buflen, answer, anslen)
const 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;
#if !_MINIX
u_short id, len;
#else /* _MINIX */
u16_t id, len;
#endif /* !_MINIX */
char *cp;
#if !_MINIX
fd_set dsmask;
struct timeval timeout;
HEADER *hp = (HEADER *) buf;
HEADER *anhp = (HEADER *) answer;
struct iovec iov[2];
#else /* _MINIX */
time_t timeout;
dns_hdr_t *hp = (dns_hdr_t *) buf;
dns_hdr_t *anhp = (dns_hdr_t *) answer;
#endif /* !_MINIX */
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);
}
v_circuit = (_res.options & RES_USEVC) || buflen > PACKETSZ;
#if !_MINIX
id = hp->id;
#else /* _MINIX */
id = hp->dh_id;
#endif /* !_MINIX */
/*
* Send request, RETRY times, or until successful
*/
for (try = 0; try < _res.retry; try++) {
for (ns = 0; ns < _res.nscount; ns++) {
#ifdef DEBUG
#if !_MINIX
if (_res.options & RES_DEBUG)
printf("Querying server (# %d) address = %s\n", ns+1,
inet_ntoa(_res.nsaddr_list[ns].sin_addr));
#else /* _MINIX */
if (_res.options & RES_DEBUG)
printf("Querying server (# %d) address = %s\n", ns+1,
inet_ntoa(_res.nsaddr_list[ns]));
#endif /* !_MINIX */
#endif /* DEBUG */
usevc:
if (v_circuit) {
#if !_MINIX
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 = (char *)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;
while (len != 0) {
n = (len > sizeof(junk) ?
sizeof(junk) : len);
if ((n = read(s, junk, n)) > 0)
len -= n;
else
break;
}
}
#else /* _MINIX */
int truncated = 0;
int nbytes;
/*
* Use virtual circuit;
* at most one attempt per server.
*/
try = _res.retry;
if (s < 0)
{
s= tcp_connect(_res.nsaddr_list[ns],
_res.nsport_list[ns], &terrno);
if (s == -1)
continue;
}
/*
* Send length & message
*/
len = htons((u_short)buflen);
nbytes= tcpip_writeall(s, (char *)&len,
sizeof(len));
if (nbytes != sizeof(len))
{
terrno= errno;
#ifdef DEBUG
if (_res.options & RES_DEBUG)
fprintf(stderr, "write failed: %s\n",
strerror(terrno));
#endif /* DEBUG */
close(s);
s= -1;
continue;
}
nbytes= tcpip_writeall(s, buf, buflen);
if (nbytes != buflen)
{
terrno= errno;
#ifdef DEBUG
if (_res.options & RES_DEBUG)
fprintf(stderr, "write failed: %s\n",
strerror(terrno));
#endif /* DEBUG */
close(s);
s= -1;
continue;
}
/*
* Receive length & response
*/
cp = answer;
len = sizeof(short);
while (len != 0)
{
n = read(s, (char *)cp, (int)len);
if (n <= 0)
break;
cp += n;
assert(len >= n);
len -= n;
}
if (len) {
terrno = errno;
#ifdef DEBUG
if (_res.options & RES_DEBUG)
fprintf(stderr, "read failed: %s\n",
strerror(terrno));
#endif /* DEBUG */
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);
if (n <= 0)
break;
cp += n;
assert(len >= n);
len -= n;
}
if (len) {
terrno = errno;
#ifdef DEBUG
if (_res.options & RES_DEBUG)
fprintf(stderr, "read failed: %s\n",
strerror(terrno));
#endif /* DEBUG */
close(s);
s= -1;
continue;
}
if (truncated) {
/*
* Flush rest of answer
* so connection stays in synch.
*/
anhp->dh_flag1 |= DHF_TC;
len = resplen - anslen;
while (len != 0) {
n = (len > sizeof(junk) ?
sizeof(junk) : len);
n = read(s, junk, n);
if (n <= 0)
{
assert(len >= n);
len -= n;
}
else
break;
}
}
#endif /* _MINIX */
} else {
#if !_MINIX
/*
* 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 /* BSD */
/*
* 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;
}
#else /* _MINIX */
/*
* Use datagrams.
*/
if (s < 0) {
s = udp_connect();
if (s < 0) {
terrno = errno;
#ifdef DEBUG
if (_res.options & RES_DEBUG)
perror("udp_connect failed");
#endif /* DEBUG */
continue;
}
}
if (udp_sendto(s, buf, buflen, _res.nsaddr_list[ns],
_res.nsport_list[ns]) != buflen) {
#ifdef DEBUG
if (_res.options & RES_DEBUG)
perror("sendto");
#endif /* DEBUG */
continue;
}
/*
* Wait for reply
*/
timeout= (_res.retrans << try);
if (try > 0)
timeout /= _res.nscount;
if (timeout <= 0)
timeout= 1;
wait:
if ((resplen= udp_receive(s, answer, anslen, timeout))
== -1)
{
if (errno == EINTR)
{
/*
* timeout
*/
#ifdef DEBUG
if (_res.options & RES_DEBUG)
printf("timeout\n");
#endif /* DEBUG */
gotsomewhere = 1;
}
else
{
#ifdef DEBUG
if (_res.options & RES_DEBUG)
perror("udp_receive");
#endif /* DEBUG */
}
continue;
}
gotsomewhere = 1;
if (id != anhp->dh_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->dh_flag1 & DHF_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;
}
#endif /* !_MINIX */
}
#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.
*/
void
_res_close()
{
if (s != -1) {
(void) close(s);
s = -1;
}
}
#if _MINIX
static int tcp_connect(host, port, terrno)
ipaddr_t host;
tcpport_t port;
int *terrno;
{
char *dev_name;
int fd;
int error;
nwio_tcpconf_t tcpconf;
nwio_tcpcl_t clopt;
dev_name= getenv("TCP_DEVICE");
if (!dev_name)
dev_name= TCP_DEVICE;
fd= open(dev_name, O_RDWR);
if (fd == -1)
{
*terrno= errno;
return -1;
}
tcpconf.nwtc_flags= NWTC_EXCL | NWTC_LP_SEL | NWTC_SET_RA | NWTC_SET_RP;
tcpconf.nwtc_remaddr= host;
tcpconf.nwtc_remport= port;
error= ioctl(fd, NWIOSTCPCONF, &tcpconf);
if (error == -1)
{
*terrno= errno;
close(fd);
return -1;
}
clopt.nwtcl_flags= 0;
error= ioctl(fd, NWIOTCPCONN, &clopt);
if (error == -1)
{
*terrno= errno;
close(fd);
return -1;
}
*terrno= 0;
return fd;
}
static int tcpip_writeall(fd, buf, siz)
int fd;
const char *buf;
size_t siz;
{
size_t siz_org;
int nbytes;
siz_org= siz;
while (siz)
{
nbytes= write(fd, buf, siz);
if (nbytes <= 0)
return siz_org-siz;
assert(siz >= nbytes);
buf += nbytes;
siz -= nbytes;
}
return siz_org;
}
static int udp_connect()
{
nwio_udpopt_t udpopt;
char *dev_name;
int fd, r, terrno;
dev_name= getenv("UDP_DEVICE");
if (!dev_name)
dev_name= UDP_DEVICE;
fd= open(dev_name, O_RDWR);
if (fd == -1)
return -1;
udpopt.nwuo_flags= NWUO_COPY | NWUO_LP_SEL | NWUO_EN_LOC |
NWUO_EN_BROAD | NWUO_RP_ANY | NWUO_RA_ANY | NWUO_RWDATALL |
NWUO_DI_IPOPT;
r= ioctl(fd, NWIOSUDPOPT, &udpopt);
if (r == -1)
{
terrno= errno;
close(fd);
errno= terrno;
return -1;
}
return fd;
}
static int udp_sendto(fd, buf, buflen, addr, port)
int fd;
const char *buf;
unsigned buflen;
ipaddr_t addr;
udpport_t port;
{
char *newbuf;
udp_io_hdr_t *udp_io_hdr;
int r, terrno;
newbuf= malloc(sizeof(*udp_io_hdr) + buflen);
if (newbuf == NULL)
{
errno= ENOMEM;
return -1;
}
udp_io_hdr= (udp_io_hdr_t *)newbuf;
udp_io_hdr->uih_dst_addr= addr;
udp_io_hdr->uih_dst_port= port;
udp_io_hdr->uih_ip_opt_len= 0;
udp_io_hdr->uih_data_len= buflen;
memcpy(newbuf + sizeof(*udp_io_hdr), buf, buflen);
r= write(fd, newbuf, sizeof(*udp_io_hdr) + buflen);
terrno= errno;
free(newbuf);
if (r >= sizeof(*udp_io_hdr))
r -= sizeof(*udp_io_hdr);
errno= terrno;
return r;
}
static void alarm_handler(sig)
int sig;
{
signal(SIGALRM, alarm_handler);
alarm(1);
}
static int udp_receive(fd, buf, buflen, timeout)
int fd;
char *buf;
unsigned buflen;
time_t timeout;
{
char *newbuf;
udp_io_hdr_t *udp_io_hdr;
int r, terrno;
void (*u_handler) _ARGS(( int sig ));
time_t u_timeout;
newbuf= malloc(sizeof(*udp_io_hdr) + buflen);
if (newbuf == NULL)
{
errno= ENOMEM;
return -1;
}
u_handler= signal(SIGALRM, alarm_handler);
u_timeout= alarm(timeout);
r= read(fd, newbuf, sizeof(*udp_io_hdr) + buflen);
terrno= errno;
if (r < 0 || r <= sizeof(*udp_io_hdr))
{
if (r > 0)
r= 0;
free(newbuf);
alarm(0);
signal(SIGALRM, u_handler);
alarm(u_timeout);
errno= terrno;
return r;
}
memcpy(buf, newbuf + sizeof(*udp_io_hdr), r - sizeof(*udp_io_hdr));
free(newbuf);
alarm(0);
signal(SIGALRM, u_handler);
alarm(u_timeout);
return r-sizeof(*udp_io_hdr);
}
#endif