Re: git: d195b3783fa4 - main - sctp: fix socket type created by sctp_peeloff()

> On 2. Feb 2026, at 20:28, Gleb Smirnoff <glebius@FreeBSD.org> wrote:
> 
>  Michael,
> 
> On Sat, Jan 31, 2026 at 06:16:09PM +0000, Michael Tuexen wrote:
> M> commit d195b3783fa4de5c1a95f6d95eb9444abce6778b
> M> Author:     Michael Tuexen <tuexen@FreeBSD.org>
> M> AuthorDate: 2026-01-31 18:11:08 +0000
> M> Commit:     Michael Tuexen <tuexen@FreeBSD.org>
> M> CommitDate: 2026-01-31 18:11:08 +0000
> M> 
> M>     sctp: fix socket type created by sctp_peeloff()
> M>     
> M>     When calling sctp_peeloff() on a SOCK_SEQPACKET socket, the created
> M>     and returned socket has the type SOCK_STREAM.
> M>     This is specified in section 9.2 of RFC 6458.
> M>     
> M>     Reported by:    Xin Long
> M>     MFC after:      3 days
> M> ---
> M>  sys/kern/uipc_socket.c | 6 ++++--
> M>  1 file changed, 4 insertions(+), 2 deletions(-)
> M> 
> M> diff --git a/sys/kern/uipc_socket.c b/sys/kern/uipc_socket.c
> M> index efc8ebfcece2..4014006ce2e5 100644
> M> --- a/sys/kern/uipc_socket.c
> M> +++ b/sys/kern/uipc_socket.c
> M> @@ -1292,7 +1292,7 @@ solisten_enqueue(struct socket *so, int connstatus)
> M>  
> M>  #if defined(SCTP) || defined(SCTP_SUPPORT)
> M>  /*
> M> - * Socket part of sctp_peeloff().  Detach a new socket from an
> M> + * Socket part of sctp_peeloff().  Create a new socket for an
> M>   * association.  The new socket is returned with a reference.
> M>   *
> M>   * XXXGL: reduce copy-paste with solisten_clone().
> M> @@ -1304,6 +1304,8 @@ sopeeloff(struct socket *head)
> M>  
> M>   VNET_ASSERT(head->so_vnet != NULL, ("%s:%d so_vnet is NULL, head=%p",
> M>      __func__, __LINE__, head));
> M> + KASSERT(head->so_type == SOCK_SEQPACKET,
> M> +    ("%s: unexpecte so_type: %d", __func__, head->so_type));
> M>   so = soalloc(head->so_vnet);
> M>   if (so == NULL) {
> M>   log(LOG_DEBUG, "%s: pcb %p: New socket allocation failure: "
> M> @@ -1311,7 +1313,7 @@ sopeeloff(struct socket *head)
> M>      __func__, head->so_pcb);
> M>   return (NULL);
> M>   }
> M> - so->so_type = head->so_type;
> M> + so->so_type = SOCK_STREAM;
> M>   so->so_options = head->so_options;
> M>   so->so_linger = head->so_linger;
> M>   so->so_state = (head->so_state & SS_NBIO) | SS_ISCONNECTED;
> 
> This creates a socket where:
> 
> so->so_type != so->so_proto->pr_type.
> 
> I'm not sure this is a good idea.  I was actually looking into removing so_type
> at all.  What does SCTP idea is about this peel-off thing?  If the resulting
> socket is a stream one, shouldn't its so_proto point at sctp_stream_protosw?
Yes, that makes sense.
But this is now a generic routine (I think it was an SCTP specific one in the past),
how can I refer to it without using sctp_stream_protosw?

Best regards
Michael
> 
> -- 
> Gleb Smirnoff