IPv6 - sobind fails with 49

[Trond Endrestøl]

On Fri, 28 Jun 2013 04:05-0000, Sreenivasa Honnur wrote:

> I am writing a kernel socket program which binds to a IPv6 address, so bind always fails with 49. Below is the code snippet I am using, is something wrong here?
> 
> roundhay# uname -a
> FreeBSD roundhay 9.1-RELEASE FreeBSD 9.1-RELEASE #2: Mon Apr  8 16:15:06 IST 2013     root at roundhay:/usr/obj/home/freebsd.org/sys/TOED<mailto:root at roundhay:/usr/obj/home/freebsd.org/sys/TOED>  amd64
> 
> Ifconfig/ping6 output:
> ======================
> cxgbe1: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> metric 0 mtu 1500
>         options=6c07bb<RXCSUM,TXCSUM,VLAN_MTU,VLAN_HWTAGGING,JUMBO_MTU,VLAN_HWCSUM,TSO4,TSO6,LRO,VLAN_HWTSO,LINKSTATE,RXCSUM_IPV6,TXCSUM_IPV6>
>         ether 00:07:43:11:89:88
>         inet6 2010::102 prefixlen 64
>         inet6 fe80::207:43ff:fe11:8988%cxgbe1 prefixlen 64 scopeid 0xd
>         inet6 fe80::1%cxgbe1 prefixlen 64 scopeid 0xd
>         nd6 options=21<PERFORMNUD,AUTO_LINKLOCAL>
>         media: Ethernet 10Gbase-SR <full-duplex>
>         status: active
> 
> roundhay# ping6 2010::101
> PING6(56=40+8+8 bytes) 2010::102 --> 2010::101
> 16 bytes from 2010::101, icmp_seq=0 hlim=64 time=0.915 ms
> 16 bytes from 2010::101, icmp_seq=1 hlim=64 time=0.168 ms
> ^C
> --- 2010::101 ping6 statistics ---
> 2 packets transmitted, 2 packets received, 0.0% packet loss
> round-trip min/avg/max/std-dev = 0.168/0.541/0.915/0.374 ms

Warning: I haven't dabbled in programming FreeBSD kernel internals, 
but I have done some socket programming some years ago.

You failed to present the line declaring sock. The prototype for 
socreate is:

  int
  socreate(int dom, struct socket **aso, int type, int proto,
           struct ucred *cred, struct thread *td);

The second argument expects a pointer to a pointer to a socket (a 
struct socket). The memory for the socket will be allocated by 
socreate() and a pointer returned through the formal argument aso.

I only hope you declared sock as:

  struct socket *sock;

Next, it would probably be wise to clear saddr6 before assigning 
values to its members, something along:

  memset((void *)&saddr6, 0, sizeof(saddr6));

or even:

  bzero((void *)&saddr6, sizeof(saddr6));

That's all I can think of atm. Maybe someone more knowledgeable on 
FreeBSD internals can assist you further.

> Code:
> 
>             struct sockaddr_in6 saddr6;
>             rv = socreate(AF_INET6, &sock, SOCK_STREAM, IPPROTO_TCP,
>                                 td->td_ucred, td);
> 
>                 if (rv != 0) {
>                         printf("sock create ipv6 %s failed %d.\n",
>                                         tbuf, rv);
>                         return NULL;
>                 }
> 
>                 saddr6.sin6_family = AF_INET6;
>                 rv = inet_pton(AF_INET6, "2010::102", &saddr6.sin6_addr); ==> returns 1, which indicates it's a valid IPV6 address
>                 printf("inet_pton retunred:%d\n", rv);
> 
>                 saddr6.sin6_port = htons(3260);
>                 saddr6.sin6_len = sizeof(saddr6);
> 
>                 rv = sobind(sock, (struct sockaddr *)&saddr6, td); ==> fails with return value of 49

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