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552 lines
13 KiB
C
552 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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#include <sys/cdefs.h>
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__FBSDID("$FreeBSD$");
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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 <ctype.h>
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#include <errno.h>
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#include <netdb.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <resolv.h>
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#include <unistd.h>
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#include <rpcsvc/yp.h>
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#include "yp_extern.h"
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static char *
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parse(struct hostent *hp)
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{
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static char result[MAXHOSTNAMELEN * 2];
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int i;
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size_t len;
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char addr[46];
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if (hp == NULL)
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return(NULL);
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if (inet_ntop(hp->h_addrtype, hp->h_addr, addr, sizeof(addr)) == NULL)
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return(NULL);
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len = strlen(addr) + 1 + 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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len++;
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if (len > sizeof(result))
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return(NULL);
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bzero(result, sizeof(result));
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snprintf(result, sizeof(result), "%s %s", 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 (64*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(char *, int, char *, int);
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static TAILQ_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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int addrtype;
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int addrlen;
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uint32_t addr[4]; /* IPv4 or IPv6 */
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TAILQ_ENTRY(circleq_dnsentry) links;
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};
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static int pending = 0;
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int
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yp_init_resolver(void)
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{
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TAILQ_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
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circleq_dnsentry *yp_malloc_dnsent(void)
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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");
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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
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yp_send_dns_query(char *name, 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 for %s type %d", name, type);
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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 *
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yp_find_dnsqent(unsigned long id, int type)
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{
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register struct circleq_dnsentry *q;
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TAILQ_FOREACH(q, &qhead, links) {
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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
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yp_send_dns_reply(struct circleq_dnsentry *q, 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
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yp_prune_dnsq(void)
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{
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register struct circleq_dnsentry *q, *n;
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q = TAILQ_FIRST(&qhead);
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while (q != NULL) {
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q->ttl--;
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n = TAILQ_NEXT(q, links);
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if (!q->ttl) {
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TAILQ_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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q = n;
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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
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yp_run_dnsq(void)
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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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struct sockaddr_in sin;
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socklen_t len;
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int rval;
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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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if (hent != NULL) {
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if (q->type == T_PTR) {
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hent->h_addr = (char *)q->addr;
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hent->h_addrtype = q->addrtype;
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hent->h_length = q->addrlen;
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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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TAILQ_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
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yp_async_lookup_name(struct svc_req *rqstp, char *name, int af)
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{
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register struct circleq_dnsentry *q;
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socklen_t len;
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int type;
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/* Check for SOCK_DGRAM or SOCK_STREAM -- we need to know later */
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type = -1;
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len = sizeof(type);
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if (getsockopt(rqstp->rq_xprt->xp_fd, 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 = (af == AF_INET) ? T_A : T_AAAA;
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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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q->domain = _res.dnsrch;
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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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TAILQ_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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yp_prune_dnsq();
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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
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yp_async_lookup_addr(struct svc_req *rqstp, char *addr, int af)
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{
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register struct circleq_dnsentry *q;
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char buf[MAXHOSTNAMELEN], *qp;
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uint32_t abuf[4]; /* IPv4 or IPv6 */
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u_char *uaddr = (u_char *)abuf;
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socklen_t len;
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int type, n;
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/* Check for SOCK_DGRAM or SOCK_STREAM -- we need to know later */
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type = -1;
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len = sizeof(type);
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if (getsockopt(rqstp->rq_xprt->xp_fd, 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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switch (af) {
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case AF_INET:
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if (inet_aton(addr, (struct in_addr *)uaddr) != 1)
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return(YP_NOKEY);
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snprintf(buf, sizeof(buf), "%u.%u.%u.%u.in-addr.arpa",
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(uaddr[3] & 0xff), (uaddr[2] & 0xff),
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(uaddr[1] & 0xff), (uaddr[0] & 0xff));
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len = INADDRSZ;
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break;
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case AF_INET6:
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if (inet_pton(af, addr, uaddr) != 1)
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return(YP_NOKEY);
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qp = buf;
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for (n = IN6ADDRSZ - 1; n >= 0; n--) {
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qp += (size_t)sprintf(qp, "%x.%x.", uaddr[n] & 0xf,
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(uaddr[n] >> 4) & 0xf);
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}
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strlcat(buf, "ip6.arpa", sizeof(buf));
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len = IN6ADDRSZ;
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break;
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default:
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return(YP_YPERR);
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}
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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;
|
|
q->xprt = rqstp->rq_xprt;
|
|
q->ypvers = rqstp->rq_vers;
|
|
q->domain = NULL;
|
|
q->prot_type = type;
|
|
if (q->prot_type == SOCK_DGRAM)
|
|
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);
|
|
}
|
|
|
|
memcpy(q->addr, uaddr, len);
|
|
q->addrlen = len;
|
|
q->addrtype = af;
|
|
q->name = strdup(buf);
|
|
TAILQ_INSERT_HEAD(&qhead, q, links);
|
|
pending++;
|
|
|
|
if (debug)
|
|
yp_error("queueing async DNS address lookup (%d)", q->id);
|
|
|
|
yp_prune_dnsq();
|
|
return(YP_TRUE);
|
|
}
|