1130b656e5
This will make a number of things easier in the future, as well as (finally!) avoiding the Id-smashing problem which has plagued developers for so long. Boy, I'm glad we're not using sup anymore. This update would have been insane otherwise.
539 lines
13 KiB
C
539 lines
13 KiB
C
/*
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* Copyright (c) 1995, 1996
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* Bill Paul <wpaul@ctr.columbia.edu>. All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. All advertising materials mentioning features or use of this software
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* must display the following acknowledgement:
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* This product includes software developed by Bill Paul.
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* 4. Neither the name of the University nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY Bill Paul AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL Bill Paul OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* $FreeBSD$
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*/
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/*
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* Do standard and reverse DNS lookups using the resolver library.
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* Take care of all the dirty work here so the main program only has to
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* pass us a pointer to an array of characters.
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*
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* We have to use direct resolver calls here otherwise the YP server
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* could end up looping by calling itself over and over again until
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* it disappeared up its own belly button.
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*/
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#include <sys/param.h>
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#include <sys/socket.h>
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#include <sys/time.h>
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#include <sys/fcntl.h>
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#include <sys/queue.h>
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#include <netinet/in.h>
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#include <arpa/inet.h>
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#include <arpa/nameser.h>
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#include <stdio.h>
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#include <ctype.h>
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#include <resolv.h>
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#include <netdb.h>
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#include <unistd.h>
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#include <stdlib.h>
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#include <string.h>
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#include <errno.h>
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#include <err.h>
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#include <rpcsvc/yp.h>
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#include "yp_extern.h"
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#ifndef lint
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static const char rcsid[] = "$FreeBSD$";
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#endif
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static char *parse(hp)
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struct hostent *hp;
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{
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static char result[MAXHOSTNAMELEN * 2];
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int len,i;
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struct in_addr addr;
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if (hp == NULL)
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return(NULL);
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len = 16 + strlen(hp->h_name);
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for (i = 0; hp->h_aliases[i]; i++)
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len += strlen(hp->h_aliases[i]) + 1;
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bzero(result, sizeof(result));
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bcopy(hp->h_addr, &addr, sizeof(struct in_addr));
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snprintf(result, sizeof(result), "%s %s", inet_ntoa(addr), hp->h_name);
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for (i = 0; hp->h_aliases[i]; i++) {
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strcat(result, " ");
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strcat(result, hp->h_aliases[i]);
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}
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return ((char *)&result);
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}
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#define MAXPACKET 1024
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#define DEF_TTL 50
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#define BY_DNS_ID 1
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#define BY_RPC_XID 2
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extern struct hostent *__dns_getanswer __P((char *, int, char *, int));
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static CIRCLEQ_HEAD(dns_qhead, circleq_dnsentry) qhead;
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struct circleq_dnsentry {
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SVCXPRT *xprt;
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unsigned long xid;
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struct sockaddr_in client_addr;
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unsigned long ypvers;
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unsigned long id;
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unsigned long ttl;
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unsigned long type;
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unsigned short prot_type;
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char **domain;
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char *name;
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struct in_addr addr;
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CIRCLEQ_ENTRY(circleq_dnsentry) links;
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};
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static int pending = 0;
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int yp_init_resolver()
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{
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CIRCLEQ_INIT(&qhead);
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if (!(_res.options & RES_INIT) && res_init() == -1) {
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yp_error("res_init failed");
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return(1);
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}
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if ((resfd = socket(AF_INET, SOCK_DGRAM, 0)) == -1) {
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yp_error("couldn't create socket");
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return(1);
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}
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if (fcntl(resfd, F_SETFL, O_NONBLOCK) == -1) {
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yp_error("couldn't make resolver socket non-blocking");
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return(1);
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}
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return(0);
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}
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static struct circleq_dnsentry *yp_malloc_dnsent()
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{
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register struct circleq_dnsentry *q;
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q = (struct circleq_dnsentry *)malloc(sizeof(struct circleq_dnsentry));
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if (q == NULL) {
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yp_error("failed to malloc() circleq dns entry: %s",
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strerror(errno));
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return(NULL);
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}
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return(q);
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}
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/*
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* Transmit a query.
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*/
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static unsigned long yp_send_dns_query(name, type)
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char *name;
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int type;
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{
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char buf[MAXPACKET];
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int n;
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HEADER *hptr;
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int ns;
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int rval;
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unsigned long id;
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bzero(buf, sizeof(buf));
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n = res_mkquery(QUERY,name,C_IN,type,NULL,0,NULL,buf,sizeof(buf));
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if (n <= 0) {
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yp_error("res_mkquery failed");
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return(0);
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}
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hptr = (HEADER *)&buf;
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id = ntohs(hptr->id);
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for (ns = 0; ns < _res.nscount; ns++) {
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rval = sendto(resfd, buf, n, 0,
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(struct sockaddr *)&_res.nsaddr_list[ns],
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sizeof(struct sockaddr));
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if (rval == -1) {
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yp_error("sendto failed");
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return(0);
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}
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}
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return(id);
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}
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static struct circleq_dnsentry *yp_find_dnsqent(id, type)
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unsigned long id;
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int type;
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{
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register struct circleq_dnsentry *q;
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for (q = qhead.cqh_first; q != (void *)&qhead; q = q->links.cqe_next) {
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switch(type) {
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case BY_RPC_XID:
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if (id == q->xid)
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return(q);
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break;
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case BY_DNS_ID:
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default:
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if (id == q->id)
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return(q);
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break;
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}
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}
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return (NULL);
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}
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static void yp_send_dns_reply(q, buf)
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struct circleq_dnsentry *q;
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char *buf;
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{
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ypresponse result_v1;
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ypresp_val result_v2;
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unsigned long xid;
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struct sockaddr_in client_addr;
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xdrproc_t xdrfunc;
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char *result;
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/*
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* Set up correct reply struct and
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* XDR filter depending on ypvers.
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*/
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switch(q->ypvers) {
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case YPVERS:
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bzero((char *)&result_v2, sizeof(result_v2));
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if (buf == NULL)
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result_v2.stat = YP_NOKEY;
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else {
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result_v2.val.valdat_len = strlen(buf);
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result_v2.val.valdat_val = buf;
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result_v2.stat = YP_TRUE;
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}
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result = (char *)&result_v2;
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xdrfunc = (xdrproc_t)xdr_ypresp_val;
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break;
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case YPOLDVERS:
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/*
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* The odds are we will _never_ execute this
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* particular code, but we include it anyway
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* for the sake of completeness.
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*/
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bzero((char *)&result_v1, sizeof(result_v1));
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result_v1.yp_resptype = YPRESP_VAL;
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# define YPVAL ypresponse_u.yp_resp_valtype
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if (buf == NULL)
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result_v1.YPVAL.stat = YP_NOKEY;
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else {
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result_v1.YPVAL.val.valdat_len = strlen(buf);
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result_v1.YPVAL.val.valdat_val = buf;
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result_v1.YPVAL.stat = YP_TRUE;
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}
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result = (char *)&result_v1;
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xdrfunc = (xdrproc_t)xdr_ypresponse;
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break;
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default:
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yp_error("Bad YP program version (%lu)!",q->ypvers);
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return;
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break;
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}
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if (debug)
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yp_error("Sending dns reply to %s (%lu)",
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inet_ntoa(q->client_addr.sin_addr), q->id);
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/*
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* XXX This is disgusting. There's basically one transport
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* handle for UDP, but we're holding off on replying to a
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* client until we're ready, by which time we may have received
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* several other queries from other clients with different
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* transaction IDs. So to make the delayed response thing work,
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* we have to save the transaction ID and client address of
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* each request, then jam them into the transport handle when
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* we're ready to send a reply. Then after we've send the reply,
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* we put the old transaction ID and remote address back the
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* way we found 'em. This is _INCREDIBLY_ non-portable; it's
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* not even supported by the RPC library.
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*/
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/*
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* XXX Don't frob the transaction ID for TCP handles.
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*/
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if (q->prot_type == SOCK_DGRAM)
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xid = svcudp_set_xid(q->xprt, q->xid);
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client_addr = q->xprt->xp_raddr;
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q->xprt->xp_raddr = q->client_addr;
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if (!svc_sendreply(q->xprt, xdrfunc, result))
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yp_error("svc_sendreply failed");
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/*
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* Now that we sent the reply,
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* put the handle back the way it was.
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*/
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if (q->prot_type == SOCK_DGRAM)
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svcudp_set_xid(q->xprt, xid);
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q->xprt->xp_raddr = client_addr;
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return;
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}
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/*
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* Decrement TTL on all queue entries, possibly nuking
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* any that have been around too long without being serviced.
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*/
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void yp_prune_dnsq()
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{
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register struct circleq_dnsentry *q;
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for (q = qhead.cqh_first; q != (void *)&qhead; q = q->links.cqe_next) {
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q->ttl--;
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if (!q->ttl) {
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CIRCLEQ_REMOVE(&qhead, q, links);
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free(q->name);
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free(q);
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pending--;
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}
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}
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if (pending < 0)
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pending = 0;
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return;
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}
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/*
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* Data is pending on the DNS socket; check for valid replies
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* to our queries and dispatch them to waiting clients.
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*/
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void yp_run_dnsq()
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{
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register struct circleq_dnsentry *q;
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char buf[sizeof(HEADER) + MAXPACKET];
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char retrybuf[MAXHOSTNAMELEN];
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struct sockaddr_in sin;
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int rval;
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int len;
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HEADER *hptr;
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struct hostent *hent;
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if (debug)
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yp_error("Running dns queue");
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bzero(buf, sizeof(buf));
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len = sizeof(struct sockaddr_in);
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rval = recvfrom(resfd, buf, sizeof(buf), 0,
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(struct sockaddr *)&sin, &len);
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if (rval == -1) {
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yp_error("recvfrom failed: %s", strerror(errno));
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return;
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}
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/*
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* We may have data left in the socket that represents
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* replies to earlier queries that we don't care about
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* anymore. If there are no lookups pending or the packet
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* ID doesn't match any of the queue IDs, just drop it
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* on the floor.
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*/
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hptr = (HEADER *)&buf;
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if (!pending ||
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(q = yp_find_dnsqent(ntohs(hptr->id), BY_DNS_ID)) == NULL) {
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/* ignore */
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return;
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}
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if (debug)
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yp_error("Got dns reply from %s", inet_ntoa(sin.sin_addr));
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hent = __dns_getanswer(buf, rval, q->name, q->type);
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/*
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* If the lookup failed, try appending one of the domains
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* from resolv.conf. If we have no domains to test, the
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* query has failed.
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*/
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if (hent == NULL) {
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if (h_errno == TRY_AGAIN && q->domain && *q->domain) {
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snprintf(retrybuf, sizeof(retrybuf), "%s.%s",
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q->name, *q->domain);
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if (debug)
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yp_error("Retrying with: %s", retrybuf);
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q->id = yp_send_dns_query(retrybuf, q->type);
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q->ttl = DEF_TTL;
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q->domain++;
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return;
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}
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} else {
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if (q->type == T_PTR) {
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hent->h_addr = (char *)&q->addr.s_addr;
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hent->h_length = sizeof(struct in_addr);
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}
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}
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/* Got an answer ready for a client -- send it off. */
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yp_send_dns_reply(q, parse(hent));
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pending--;
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CIRCLEQ_REMOVE(&qhead, q, links);
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free(q->name);
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free(q);
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/* Decrement TTLs on other entries while we're here. */
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yp_prune_dnsq();
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return;
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}
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/*
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* Queue and transmit an asynchronous DNS hostname lookup.
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*/
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ypstat yp_async_lookup_name(rqstp, name)
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struct svc_req *rqstp;
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char *name;
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{
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register struct circleq_dnsentry *q;
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int type, len;
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/* Check for SOCK_DGRAM or SOCK_STREAM -- we need to know later */
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type = -1; len = sizeof(type);
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if (getsockopt(rqstp->rq_xprt->xp_sock, SOL_SOCKET,
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SO_TYPE, &type, &len) == -1) {
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yp_error("getsockopt failed: %s", strerror(errno));
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return(YP_YPERR);
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}
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/* Avoid transmitting dupe requests. */
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if (type == SOCK_DGRAM &&
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yp_find_dnsqent(svcudp_get_xid(rqstp->rq_xprt),BY_RPC_XID) != NULL)
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return(YP_TRUE);
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if ((q = yp_malloc_dnsent()) == NULL)
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return(YP_YPERR);
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q->type = T_A;
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q->ttl = DEF_TTL;
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q->xprt = rqstp->rq_xprt;
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q->ypvers = rqstp->rq_vers;
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q->prot_type = type;
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if (q->prot_type == SOCK_DGRAM)
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q->xid = svcudp_get_xid(q->xprt);
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q->client_addr = q->xprt->xp_raddr;
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if (!strchr(name, '.'))
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q->domain = _res.dnsrch;
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else
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q->domain = NULL;
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q->id = yp_send_dns_query(name, q->type);
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if (q->id == 0) {
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yp_error("DNS query failed");
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free(q);
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return(YP_YPERR);
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}
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q->name = strdup(name);
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CIRCLEQ_INSERT_HEAD(&qhead, q, links);
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pending++;
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if (debug)
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yp_error("Queueing async DNS name lookup (%d)", q->id);
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return(YP_TRUE);
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}
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/*
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* Queue and transmit an asynchronous DNS IP address lookup.
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*/
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ypstat yp_async_lookup_addr(rqstp, addr)
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struct svc_req *rqstp;
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char *addr;
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{
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register struct circleq_dnsentry *q;
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char buf[MAXHOSTNAMELEN];
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int a, b, c, d;
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int type, len;
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/* Check for SOCK_DGRAM or SOCK_STREAM -- we need to know later */
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type = -1; len = sizeof(type);
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if (getsockopt(rqstp->rq_xprt->xp_sock, SOL_SOCKET,
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SO_TYPE, &type, &len) == -1) {
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yp_error("getsockopt failed: %s", strerror(errno));
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return(YP_YPERR);
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}
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/* Avoid transmitting dupe requests. */
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if (type == SOCK_DGRAM &&
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yp_find_dnsqent(svcudp_get_xid(rqstp->rq_xprt),BY_RPC_XID) != NULL)
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return(YP_TRUE);
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if ((q = yp_malloc_dnsent()) == NULL)
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return(YP_YPERR);
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if (sscanf(addr, "%d.%d.%d.%d", &a, &b, &c, &d) != 4)
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return(YP_NOKEY);
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snprintf(buf, sizeof(buf), "%d.%d.%d.%d.in-addr.arpa", d, c, b, a);
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if (debug)
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yp_error("DNS address is: %s", buf);
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q->type = T_PTR;
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q->ttl = DEF_TTL;
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q->xprt = rqstp->rq_xprt;
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q->ypvers = rqstp->rq_vers;
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q->domain = NULL;
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q->prot_type = type;
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if (q->prot_type == SOCK_DGRAM)
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q->xid = svcudp_get_xid(q->xprt);
|
|
q->client_addr = q->xprt->xp_raddr;
|
|
q->id = yp_send_dns_query(buf, q->type);
|
|
|
|
if (q->id == 0) {
|
|
yp_error("DNS query failed");
|
|
free(q);
|
|
return(YP_YPERR);
|
|
}
|
|
|
|
inet_aton(addr, &q->addr);
|
|
q->name = strdup(buf);
|
|
CIRCLEQ_INSERT_HEAD(&qhead, q, links);
|
|
pending++;
|
|
|
|
if (debug)
|
|
yp_error("Queueing async DNS address lookup (%d)", q->id);
|
|
|
|
return(YP_TRUE);
|
|
}
|