Date: Mon, 28 Jul 2003 12:40:51 -0400 From: Jonathan Lennox <lennox@cs.columbia.edu> To: sub_0@netcabo.pt Cc: freebsd-gnats-submit@FreeBSD.org Subject: Re: misc/54189: DNS resolver should resolve hostnames with underscores Message-ID: <16165.21011.781126.341394@grandcentral.cs.columbia.edu> In-Reply-To: <1058576063.1430.20.camel@suzy.unbreakable.homeunix.org> References: <1058576063.1430.20.camel@suzy.unbreakable.homeunix.org>
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On , July 19 2003, "M=E1rio Freitas" wrote to "freebsd-bugs@FreeBSD.org=
, lennox@cs.columbia.edu" saying:
> The problem you submitted is due to mozilla's gethostbyname() own(bad=
)
> implementation. FreeBSD's resolver can deal with underscores in
> hostnames without any problem at all. I think you should submit that
> problem to mozilla's bug tracking system(yes I succeded resolving tha=
t
> hostname in FreeBSD 4.8 and 5.1).
Not so, at least if you go through the gethostbyname() or getaddrinfo()=
APIs. I've attached a small program that exercises both APIs, compiled=
it on both FreeBSD 4.8-RELEASE and on Red Hat Linux 7.1, and executed b=
oth
on the same FreeBSD 4.8 machine (the Linux binary running under emulati=
on):
conrail $ ./gethostbyname dear=5Fraed.blogspot.com
dear=5Fraed.blogspot.com: gethostbyname lookup failed: Unknown server e=
rror (3)
dear=5Fraed.blogspot.com: getaddrinfo lookup failed: Non-recoverable fa=
ilure in name resolution (4)
conrail $ ./gethostbyname-linux dear=5Fraed.blogspot.com
dear=5Fraed.blogspot.com [ghbn]: 216.34.7.189=20
dear=5Fraed.blogspot.com [gai]: 216.34.7.189 216.34.7.189 216.34.7.189=20=
The FreeBSD 'nslookup' and 'host' programs, which bypass these APIs and=
do
DNS queries directly, can indeed resolve the hostname:
conrail $ nslookup dear=5Fraed.blogspot.com
Server: sutton.cs.columbia.edu
Address: 128.59.22.38
Non-authoritative answer:
Name: dear=5Fraed.blogspot.com
Address: 216.34.7.189
conrail $ host dear=5Fraed.blogspot.com
dear=5Fraed.blogspot.com has address 216.34.7.189
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#include <stdio.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <string.h>
#include <stdlib.h>
#include <netdb.h>
int main(int argc, char *argv[])
{
int i;
struct addrinfo hints;
if (argc < 2) {
fprintf(stderr, "Usage: %s hostname [...]", argv[0]);
exit(1);
}
memset(&hints, 0, sizeof(hints));
hints.ai_family = AF_INET;
for (i = 1; i < argc; i++) {
int ret;
struct hostent *he;
struct addrinfo *ai;
he = gethostbyname(argv[i]);
if (he == NULL) {
printf("%s: gethostbyname lookup failed: %s (%d)\n", argv[i],
hstrerror(h_errno), h_errno);
}
else {
int j;
printf("%s [ghbn]: ", argv[i]);
for (j = 0; he->h_addr_list[j] != NULL; j++) {
printf("%s ", inet_ntoa(*(struct in_addr*)(he->h_addr_list[j])));
}
printf("\n");
}
ret = getaddrinfo(argv[i], NULL, &hints, &ai);
if (ret != 0) {
printf("%s: getaddrinfo lookup failed: %s (%d)\n", argv[i],
gai_strerror(ret), ret);
}
else {
struct addrinfo* this_ai;
printf("%s [gai]: ", argv[i]);
for (this_ai = ai; this_ai != NULL; this_ai = this_ai->ai_next) {
printf("%s ",
inet_ntoa(((struct sockaddr_in*)(this_ai->ai_addr))->sin_addr));
}
printf("\n");
freeaddrinfo(ai);
}
}
return 0;
}
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--
Jonathan Lennox
lennox@cs.columbia.edu
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