141 lines
2.4 KiB
C
141 lines
2.4 KiB
C
#include <u.h>
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#include <libc.h>
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#include <bio.h>
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#include <ctype.h>
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#include <ndb.h>
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#include "dns.h"
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#include "ip.h"
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static int domount;
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static char *mtpt, *dns, *srv;
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static int
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setup(int argc, char **argv)
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{
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int fd;
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if(argc == 1){
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domount = 0;
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mtpt = argv[0];
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}
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fd = open(dns, ORDWR);
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if(fd < 0){
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if(domount == 0)
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sysfatal("can't open %s: %r", dns);
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fd = open(srv, ORDWR);
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if(fd < 0)
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sysfatal("can't open %s: %r", srv);
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if(mount(fd, -1, mtpt, MBEFORE, "", '9') < 0)
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sysfatal("can't mount(%s, %s): %r", srv, mtpt);
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fd = open(dns, ORDWR);
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if(fd < 0)
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sysfatal("can't open %s: %r", dns);
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}
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return fd;
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}
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static void
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querydns(int fd, char *line, int n)
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{
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char buf[1024];
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seek(fd, 0, 0);
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if(write(fd, line, n) != n) {
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print("!%r\n");
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return;
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}
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seek(fd, 0, 0);
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buf[0] = '\0';
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while((n = read(fd, buf, sizeof(buf))) > 0){
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buf[n] = '\0';
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print("%s\n", buf);
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}
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}
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static void
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query(int fd)
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{
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int n, len;
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char *lp, *p, *np;
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char buf[1024], line[1024];
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Biobuf in;
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Binit(&in, 0, OREAD);
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for(print("> "); lp = Brdline(&in, '\n'); print("> ")){
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n = Blinelen(&in) -1;
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while(isspace(lp[n]))
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lp[n--] = 0;
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n++;
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while(isspace(*lp)){
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lp++;
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n--;
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}
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if(!*lp)
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continue;
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strcpy(line, lp);
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/* default to an "ip" request if alpha, "ptr" if numeric */
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if(strchr(line, ' ') == nil)
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if(strcmp(ipattr(line), "ip") == 0) {
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strcat(line, " ptr");
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n += 4;
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} else {
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strcat(line, " ip");
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n += 3;
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}
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/* inverse queries may need to be permuted */
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if(n > 4 && strcmp(" ptr", &line[n-4]) == 0 &&
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cistrstr(line, ".arpa") == nil){
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/* TODO: reversing v6 addrs is harder */
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for(p = line; *p; p++)
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if(*p == ' '){
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*p = '.';
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break;
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}
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np = buf;
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len = 0;
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while(p >= line){
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len++;
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p--;
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if(*p == '.'){
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memmove(np, p+1, len);
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np += len;
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len = 0;
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}
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}
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memmove(np, p+1, len);
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np += len;
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strcpy(np, "in-addr.arpa ptr"); /* TODO: ip6.arpa for v6 */
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strcpy(line, buf);
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n = strlen(line);
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}
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querydns(fd, line, n);
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}
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Bterm(&in);
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}
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void
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main(int argc, char *argv[])
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{
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mtpt = "/net";
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dns = "/net/dns";
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srv = "/srv/dns";
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domount = 1;
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ARGBEGIN {
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case 'x':
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mtpt = "/net.alt";
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dns = "/net.alt/dns";
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srv = "/srv/dns_net.alt";
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break;
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default:
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fprint(2, "usage: %s [-x] [dns-mount-point]\n", argv0);
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exits("usage");
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} ARGEND;
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query(setup(argc, argv));
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exits(0);
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}
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