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#include <u.h>
#include <libc.h>
#include <bio.h>
#include <ctype.h>
#include <ndb.h>
#include "dns.h"
#include "ip.h"
static void
querydns(int fd, char *line, int n)
{
char buf[8192+1];
seek(fd, 0, 0);
if(write(fd, line, n) != n) {
print("!%r\n");
return;
}
seek(fd, 0, 0);
while((n = read(fd, buf, sizeof(buf)-1)) > 0){
buf[n++] = '\n';
write(1, buf, n);
}
}
/*
* convert address into a reverse lookup address
*/
static void
mkptrname(char *ip, char *rip, int rlen)
{
uchar a[IPaddrlen];
char *p, *e;
int i;
if(cistrstr(ip, "in-addr.arpa") || cistrstr(ip, "ip6.arpa") || parseip(a, ip) == -1)
snprint(rip, rlen, "%s", ip);
else if(isv4(a))
snprint(rip, rlen, "%ud.%ud.%ud.%ud.in-addr.arpa",
a[15], a[14], a[13], a[12]);
else{
p = rip;
e = rip + rlen;
for(i = 15; i >= 0; i--){
p = seprint(p, e, "%ux.", a[i]&0xf);
p = seprint(p, e, "%ux.", a[i]>>4);
}
seprint(p, e, "ip6.arpa");
}
}
static void
query(int fd)
{
int n;
char *lp;
char buf[1024], line[1024];
Biobuf in;
Binit(&in, 0, OREAD);
for(print("> "); lp = Brdline(&in, '\n'); print("> ")){
n = Blinelen(&in) -1;
while(isspace(lp[n]))
lp[n--] = 0;
n++;
while(isspace(*lp)){
lp++;
n--;
}
if(!*lp)
continue;
strcpy(line, lp);
/* default to an "ip" request if alpha, "ptr" if numeric */
if(strchr(line, ' ') == nil)
if(strcmp(ipattr(line), "ip") == 0) {
strcat(line, " ptr");
n += 4;
} else {
strcat(line, " ip");
n += 3;
}
if(n > 4 && strcmp(" ptr", &line[n-4]) == 0){
line[n-4] = 0;
mkptrname(line, buf, sizeof buf);
n = snprint(line, sizeof line, "%s ptr", buf);
}
querydns(fd, line, n);
}
Bterm(&in);
}
void
main(int argc, char *argv[])
{
char *dns = "/net/dns";
int fd;
ARGBEGIN {
case 'x':
dns = "/net.alt/dns";
break;
default:
fprint(2, "usage: %s [-x] [/net/dns]\n", argv0);
exits("usage");
} ARGEND;
if(argc > 0)
dns = argv[0];
fd = open(dns, ORDWR);
if(fd < 0)
sysfatal("can't open %s: %r", dns);
query(fd);
exits(0);
}
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