Re: [Lksctp-developers] SCTP_SET_PEER_PRIMARY_ADDR v4 mapped?

[Chris Hegarty <chris.hegarty@oracle.com>]

Hi Wei,

Strangely, now I can't find any consistent behavior with respect to 
setting SCTP_SET_PEER_PRIMARY_ADDR.

What I have is a simple test case that connects two 121 AF_INET6 
sockets, s1 and s2. Retrieve all local addresses of s1 using 
sctp_getladdrs. Iterate over these addresses trying to set 
SCTP_SET_PEER_PRIMARY_ADDR with each address. I run the test many times, 
sometimes all setsockopt calls succeed and sometimes some (or all) fail 
with EADDRNOTAVAIL. There doesn't appear to be any consistency, v4, v4 
mapped, v6, or loopback addresses.

Unfortunately my testcase is written in Java, but it essentially just 
wraps the native C API as I described above.

I am using a slightly old version of the kernel. Is there changes in 
this area in more recent kernels?
   # uname -a
   Linux aerrow 2.6.30.10-105.2.23.fc11.i586 #1 SMP Thu Feb 11 06:51:26
   UTC 2010 i686 i686 i386 GNU/Linux

-Chris.

On 12/ 7/10 06:35 AM, Wei Yongjun wrote:
> Hi Chris Hegarty,
>
>> On 12/ 6/10 06:23 AM, Wei Yongjun wrote:
>>>
>>>> Hi,
>>>>
>>>> I've noticed a difference in the way SCTP_SET_PEER_PRIMARY_ADDR&
>>>> SCTP_PRIMARY_ADDR socket options accept socket addresses. When setting
>>>> SCTP_PRIMARY_ADDR it appears that a v4 mapped address is accepted, but
>>>> when setting SCTP_SET_PEER_PRIMARY_ADDR it gives "Cannot assign
>>>> requested address" as if the address is not a valid local address. But
>>>> when I use the IPv4 address it appears to work as expected.
>>>>
>>>
>>> With SCTP_SET_PEER_PRIMARY_ADDR, we checked whether
>>> this address is a valid peer address, not local address. The peer
>>> must have this address in its address list after estab. Also, peer
>>> must support v4 mapped address.
>>
>> Thanks for your reply. Sorry, but I'm still confused here.
>>
>> "7.3.1. Set Peer Primary Address (SCTP_SET_PEER_PRIMARY_ADDR)
>>
>>     Requests that the peer marks the enclosed address as the association
>>     primary (see [RFC5061]).  The enclosed address must be one of the
>>     association's locally bound addresses."
>>
>> So the address passed when setting SCTP_SET_PEER_PRIMARY_ADDR must be
>> one of the locally bound addresses, not the peer address, right?
>>
>> My question is related more to the user interface when using AF_INET6
>> sockets. Why would the given address have to be an IPv4 address for
>> setting SCTP_SET_PEER_PRIMARY_ADDR, but when setting SCTP_PRIMARY_ADDR
>> it must be an IPv4 mapped address? I would expect the user interface
>> to behave consistently across these two options.
>
> Can you try the following patch?
>
> [PATCH] SCTP: Fix SCTP_SET_PEER_PRIMARY_ADDR to accpet v4mapped address
>
> SCTP_SET_PEER_PRIMARY_ADDR does not accpet v4mapped address, this
> patch will fix it by map v4mapped address to v4 address if allowed.
>
> Signed-off-by: Wei Yongjun<yjwei@cn.fujitsu.com>
> ---
>   net/sctp/socket.c |    8 ++++++++
>   1 files changed, 8 insertions(+), 0 deletions(-)
>
> diff --git a/net/sctp/socket.c b/net/sctp/socket.c
> index 6bd5543..0b9ee34 100644
> --- a/net/sctp/socket.c
> +++ b/net/sctp/socket.c
> @@ -2932,6 +2932,7 @@ static int sctp_setsockopt_peer_primary_addr(struct sock *sk, char __user *optva
>   	struct sctp_association	*asoc = NULL;
>   	struct sctp_setpeerprim	prim;
>   	struct sctp_chunk	*chunk;
> +	struct sctp_af		*af;
>   	int 			err;
>
>   	sp = sctp_sk(sk);
> @@ -2959,6 +2960,13 @@ static int sctp_setsockopt_peer_primary_addr(struct sock *sk, char __user *optva
>   	if (!sctp_state(asoc, ESTABLISHED))
>   		return -ENOTCONN;
>
> +	af = sctp_get_af_specific(prim.sspp_addr.ss_family);
> +	if (!af)
> +		return -EINVAL;
> +
> +	if (!af->addr_valid((union sctp_addr *)&prim.sspp_addr, sp, NULL))
> +		return -EADDRNOTAVAIL;
> +
>   	if (!sctp_assoc_lookup_laddr(asoc, (union sctp_addr *)&prim.sspp_addr))
>   		return -EADDRNOTAVAIL;
>