From mboxrd@z Thu Jan 1 00:00:00 1970 From: Daniel Borkmann Date: Thu, 28 Aug 2014 07:47:18 +0000 Subject: Re: uapi header mismatch with kernel ? Message-Id: <53FEDE86.2090705@redhat.com> List-Id: References: In-Reply-To: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 8bit To: linux-sctp@vger.kernel.org On 08/28/2014 09:34 AM, Daniel Borkmann wrote: > On 08/28/2014 08:33 AM, 苏庆 wrote: >> Hi all, >> >> I found that In 3.x kernel, the sctp states are defined differently >> between kernel and uapi header. This makes our application fails to >> work. >> >> Is that a mismatch or am I missing something? > > You are correct, and that's not good ... can you try out the below > kernel patch? Note, the problem is that we cannot just redefine the sctp_state_t enum back to as it was as it's accessing a function pointer lookup table, so I think it's better to just add this offset for user space now. It's read-only anyway. > From 90653829a4d406898f6906849f3eca481ec01894 Mon Sep 17 00:00:00 2001 > From: Daniel Borkmann > Date: Thu, 28 Aug 2014 09:26:36 +0200 > Subject: [PATCH] net: sctp: fix ABI through sctp_assoc_to_state helper > > Signed-off-by: Daniel Borkmann > --- > include/net/sctp/sctp.h | 13 +++++++++++++ > net/sctp/socket.c | 2 +- > 2 files changed, 14 insertions(+), 1 deletion(-) > > diff --git a/include/net/sctp/sctp.h b/include/net/sctp/sctp.h > index f6e7397..f50dccf 100644 > --- a/include/net/sctp/sctp.h > +++ b/include/net/sctp/sctp.h > @@ -320,6 +320,19 @@ static inline sctp_assoc_t sctp_assoc2id(const struct sctp_association *asoc) > return asoc ? asoc->assoc_id : 0; > } > > +static inline enum sctp_sstat_state > +sctp_assoc_to_state(const struct sctp_association *asoc) > +{ > + /* SCTP's uapi always had SCTP_EMPTY(=0) as a dummy state, but we > + * got rid of it in kernel space. Therefore SCTP_CLOSED et al > + * start at =1 in user space, but actually as =0 in kernel space. > + * Now that we may not break user space and SCTP_EMPTY is exposed > + * there, hence we need to fix it up with an ugly offset to not > + * break applications. :( > + */ > + return asoc->state + 1; > +} > + > /* Look up the association by its id. */ > struct sctp_association *sctp_id2assoc(struct sock *sk, sctp_assoc_t id); > > diff --git a/net/sctp/socket.c b/net/sctp/socket.c > index eb71d49..634a2ab 100644 > --- a/net/sctp/socket.c > +++ b/net/sctp/socket.c > @@ -4243,7 +4243,7 @@ static int sctp_getsockopt_sctp_status(struct sock *sk, int len, > transport = asoc->peer.primary_path; > > status.sstat_assoc_id = sctp_assoc2id(asoc); > - status.sstat_state = asoc->state; > + status.sstat_state = sctp_assoc_to_state(asoc); > status.sstat_rwnd = asoc->peer.rwnd; > status.sstat_unackdata = asoc->unack_data; >