Re: IPv6 && getaddrinfo(3C)
El día Thursday, July 12, 2012 a las 09:01:50PM -0500, Robert Bonomi escribió:
> > > req.ai_flags = AI_ADDRCONFIG|AI_NUMERICHOST;
> > > req.ai_family = AF_INET6;/* Same as AF_INET6. */
>
> Isn't the setting of 'req.ai_family', above, going to guarantee that
> something that "looks like" an IPv4 address will not be considered valid?
>
> After all, what *POSSIBLE* _IPv6_info_ is there about an IPv4 address?
>
> Per the manpage example, try PF_UNSPEC.
With PF_UNSPEC it works fine now, thanks for the hint; I'm attaching the
code for the client and as well one for a server creating LISTEN on IPv6
and IPv4 at the same time and handling the connections on both ports;
HIH
matthias
/* IPv6 client code using getaddrinfo */
#include
#include
#include
#include
#include
#include
#include
main(int argc, char **argv)
{
struct addrinfo req, *ans;
int code, s, n;
char buf[1024];
memset(&req, 0, sizeof(req));
req.ai_flags = 0; /* may be restricted to
AI_ADDRCONFIG|AI_NUMERICHOST|... */
/* req.ai_family = AF_INET6;/* validates only AF_INET6 */
/* req.ai_family = AF_INET; /* validates only AF_INET, i.e. IPv4 */
req.ai_family = PF_UNSPEC; /* validates IPv4 and IPv6. */
req.ai_socktype = SOCK_STREAM;
/* Use protocol TCP */
req.ai_protocol = IPPROTO_TCP; /* 0: any, IPPROTO_UDP: UDP */
printf("host: %s\n", argv[1]);
if ((code = getaddrinfo(argv[1], "ssh", &req, &ans)) != 0) {
fprintf(stderr, "ssh: getaddrinfo failed code %d: %s\n", code,
gai_strerror(code));
exit(1);
}
/* 'ans' must contain at least one addrinfo, use the first */
s = socket(ans->ai_family, ans->ai_socktype, ans->ai_protocol);
if (s < 0) {
perror("ssh: socket");
exit(3);
}
/* Connect does the bind for us */
if (connect(s, ans->ai_addr, ans->ai_addrlen) < 0) {
perror("ssh: connect");
exit(5);
}
/* just for test: read in SSH' good morning message */
n = read(s, buf, 1024);
printf ("read: %s", buf);
/*
Free answers after use
*/
freeaddrinfo(ans);
exit(0);
}
/* IPv6 server code using getaddrinfo */
#include
#include
#include
#include
#include
#include
#include
#include
#include
#include
#include
void doit()
{
printf("child forked end ended\n");
}
main(int argc, char **argv)
{
struct sockaddr_in6 from;
struct addrinfo req, *ans, *ans2;
intcode, sockFd1, sockFd2, len;
/* Set ai_flags to AI_PASSIVE to indicate that return addres s is
suitable for bind() */
memset(&req, 0, sizeof(req));
req.ai_flags = AI_PASSIVE;
req.ai_family = PF_UNSPEC; /* IPv6+IPv4: PF_UNSPEC, IPv4:
PF_INET */
req.ai_socktype = SOCK_STREAM;
req.ai_protocol = IPPROTO_TCP;
#define SLNP "3025"
if ((code = getaddrinfo(NULL, SLNP, &req, &ans)) != 0) {
fprintf(stderr, "SLNP (%s): getaddrinfo failed code %d: %s\n",
SLNP, code, gai_strerror(code));
exit(1);
}
/* 'ans' must contain at least one addrinfo and we use the first. */
/* it seems(!) that 1st one is the IPv6 when we use PF_UNSPEC */
if( (sockFd1 = socket(ans->ai_family, ans->ai_socktype,
ans->ai_protocol)) < 0) {
perror("socket");
exit(-1);
}
if (bind(sockFd1, ans->ai_addr, ans->ai_addrlen) < 0) {
perror("bind");
close(sockFd1);
exit(-1);
}
/* create the 1st LISTEN */
printf("1st (IPv6) LISTEN...\n");
listen(sockFd1, 5);
/* if there is a 2nd addrinfo provided by getaddrinfo(3C) and we will
create 2nd socket... */
ans2 = NULL;
if( ans->ai_next != NULL )
ans2 = ans->ai_next;
sockFd2 = -1; /* set to -1 to be used as this in poll, see below
*/
if( ans2 != NULL ) {
if( (sockFd2 = socket(ans2->ai_family, ans2->ai_socktype,
ans2->ai_protocol)) < 0) {
perror("socket");
exit(-1);
}
if (bind(sockFd2, ans2->ai_addr, ans2->ai_addrlen) < 0) {
perror("bind");
close(sockFd2);
exit(-1);
}
printf("2nd (IPv4) LISTEN...\n");
listen(sockFd2, 5);
}
for (;;) {
int newsockFd, len = sizeof(from), readyFd, polled;
struct pollfd fds[2];
/* we poll both fds for events and accept the one which is
ready */
fds[0].fd = sockFd1;
fds[0].events = POLLIN | POLLPRI;
fds[0].revent
Re: IPv6 && getaddrinfo(3C)
> From: Doug Hardie
> Date: Thu, 12 Jul 2012 14:21:38 -0700
> Subject: Re: IPv6 && getaddrinfo(3C)
>
> On 12 July 2012, at 07:24, Matthias Apitz wrote:
>
> > Hello,
> >
> > I'm playing around with IPv6 code on a FreeBSD 9 system and can't get
> > getaddrinfo(3C) to do what it should do as stated in its man page:
> > accept an IPv6 and IPv4 IP addr, it only works with the IPv6 form:
> >
> > $ ./a.out ::1
> > host: ::1 read: SSH-2.0-OpenSSH_5.6p1 FreeBSD-2010
> > $ ./a.out 127.0.0.1
> > host: 127.0.0.1 ssh: getaddrinfo failed code 8: hostname nor servname
> > provided, or not known
> > $ telnet 127.0.0.1 22
> > Trying 127.0.0.1... Connected to localhost. Escape character is '^]'.
> > SSH-2.0-OpenSSH_5.6p1 FreeBSD-2010
> >
> > the used C-code is attached below; what I'm doing wrong in the code?
> >
> > Thanks
> >
> > matthias
> >
> > /* IPv6 client code using getaddrinfo */
> >
> > #include
> > #include
> > #include
> > #include
> > #include
> > #include
> > #include
> >
> >
> > main(argc, argv)/* client side */
> > intargc; char *argv[];
> > {
> >
> > struct addrinforeq, *ans; int code, s, n; char buf[1024];
> >
> > memset(&req, 0, sizeof(req));
> > req.ai_flags = AI_ADDRCONFIG|AI_NUMERICHOST;
> > req.ai_family = AF_INET6; /* Same as AF_INET6. */
Isn't the setting of 'req.ai_family', above, going to guarantee that
something that "looks like" an IPv4 address will not be considered valid?
After all, what *POSSIBLE* _IPv6_info_ is there about an IPv4 address?
Per the manpage example, try PF_UNSPEC.
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Re: IPv6 && getaddrinfo(3C)
On 12 July 2012, at 07:24, Matthias Apitz wrote:
>
> Hello,
>
> I'm playing around with IPv6 code on a FreeBSD 9 system and can't get
> getaddrinfo(3C) to do what it should do as stated in its man page:
> accept an IPv6 and IPv4 IP addr, it only works with the IPv6 form:
>
> $ ./a.out ::1
> host: ::1
> read: SSH-2.0-OpenSSH_5.6p1 FreeBSD-2010
> $ ./a.out 127.0.0.1
> host: 127.0.0.1
> ssh: getaddrinfo failed code 8: hostname nor servname provided, or not known
> $ telnet 127.0.0.1 22
> Trying 127.0.0.1...
> Connected to localhost.
> Escape character is '^]'.
> SSH-2.0-OpenSSH_5.6p1 FreeBSD-2010
>
> the used C-code is attached below; what I'm doing wrong in the code?
>
> Thanks
>
> matthias
>
> /* IPv6 client code using getaddrinfo */
>
> #include
> #include
> #include
> #include
> #include
> #include
> #include
>
>
> main(argc, argv) /* client side */
> int argc;
> char *argv[];
> {
>
> struct addrinfo req, *ans;
> int code, s, n;
> char buf[1024];
>
> memset(&req, 0, sizeof(req));
> req.ai_flags = AI_ADDRCONFIG|AI_NUMERICHOST;
> req.ai_family = AF_INET6; /* Same as AF_INET6. */
> req.ai_socktype = SOCK_STREAM;
>
> /* */
> /* Use default protocol (in this case tcp) */
> /* */
>
> req.ai_protocol = 0;
>
> printf("host: %s\n", argv[1]);
> if ((code = getaddrinfo(argv[1], "ssh", &req, &ans)) != 0) {
> fprintf(stderr, "ssh: getaddrinfo failed code %d: %s\n", code,
> gai_strerror(code));
> exit(1);
> }
>
>
> /* */
> /* ans must contain at least one addrinfo, use */
> /* the first. */
> /* */
>
> s = socket(ans->ai_family, ans->ai_socktype, ans->ai_protocol);
> if (s < 0) {
> perror("ssh: socket");
> exit(3);
> }
>
> /* Connect does the bind for us */
>
> if (connect(s, ans->ai_addr, ans->ai_addrlen) < 0) {
> perror("ssh: connect");
> exit(5);
> }
>
> n = read(s, buf, 1024);
> printf ("read: %s", buf);
>
> /* */
> /* Free answers after use */
> /* */
> freeaddrinfo(ans);
>
> exit(0);
> }
>
>
I won't claim to be an expert on this, but I have used getaddrinfo successfully
in servers. The only thing I see that might be an issue is the use of zero for
ai_protocol. The comment in the man page implies that value is for servers and
not clients. I suspect you have to set the specific protocol you want. You
haven't included AI_PASSIVE so I suspect its expecting you to use the address
to contact a server.
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