On Sun, Nov 18, 2018 at 04:02:25PM +0900, Xin Long wrote: > On Sat, Nov 17, 2018 at 12:12 AM Neil Horman <nhor...@tuxdriver.com> wrote: > > > > On Thu, Nov 15, 2018 at 09:41:01PM -0200, Marcelo Ricardo Leitner wrote: > > > [ re-sending, without html this time ] > > > > > > On Thu, Nov 15, 2018, 15:26 Neil Horman <nhor...@tuxdriver.com wrote: > > > > > > > On Thu, Nov 15, 2018 at 08:25:36PM -0200, Marcelo Ricardo Leitner wrote: > > > > > On Thu, Nov 15, 2018 at 04:43:10PM -0500, Neil Horman wrote: > > > > > > On Thu, Nov 15, 2018 at 03:22:21PM -0200, Marcelo Ricardo Leitner > > > > wrote: > > > > > > > On Thu, Nov 15, 2018 at 07:14:28PM +0800, Xin Long wrote: > > > > > > > > As rfc7496#section4.5 says about SCTP_PR_SUPPORTED: > > > > > > > > > > > > > > > > This socket option allows the enabling or disabling of the > > > > > > > > negotiation of PR-SCTP support for future associations. For > > > > existing > > > > > > > > associations, it allows one to query whether or not PR-SCTP > > > > support > > > > > > > > was negotiated on a particular association. > > > > > > > > > > > > > > > > It means only sctp sock's prsctp_enable can be set. > > > > > > > > > > > > > > > > Note that for the limitation of SCTP_{CURRENT|ALL}_ASSOC, we > > > > > > > > will > > > > > > > > add it when introducing SCTP_{FUTURE|CURRENT|ALL}_ASSOC for > > > > > > > > linux > > > > > > > > sctp in another patchset. > > > > > > > > > > > > > > > > Fixes: 28aa4c26fce2 ("sctp: add SCTP_PR_SUPPORTED on sctp > > > > > > > > sockopt") > > > > > > > > Reported-by: Ying Xu <yi...@redhat.com> > > > > > > > > Signed-off-by: Xin Long <lucien....@gmail.com> > > > > > > > > --- > > > > > > > > net/sctp/socket.c | 13 +++---------- > > > > > > > > 1 file changed, 3 insertions(+), 10 deletions(-) > > > > > > > > > > > > > > > > diff --git a/net/sctp/socket.c b/net/sctp/socket.c > > > > > > > > index 739f3e5..e9b8232 100644 > > > > > > > > --- a/net/sctp/socket.c > > > > > > > > +++ b/net/sctp/socket.c > > > > > > > > @@ -3940,7 +3940,6 @@ static int > > > > sctp_setsockopt_pr_supported(struct sock *sk, > > > > > > > > unsigned int optlen) > > > > > > > > { > > > > > > > > struct sctp_assoc_value params; > > > > > > > > - struct sctp_association *asoc; > > > > > > > > int retval = -EINVAL; > > > > > > > > > > > > > > > > if (optlen != sizeof(params)) > > > > > > > > @@ -3951,16 +3950,10 @@ static int > > > > sctp_setsockopt_pr_supported(struct sock *sk, > > > > > > > > goto out; > > > > > > > > } > > > > > > > > > > > > > > > > - asoc = sctp_id2assoc(sk, params.assoc_id); > > > > > > > > - if (asoc) { > > > > > > > > - asoc->prsctp_enable = !!params.assoc_value; > > > > > > > > - } else if (!params.assoc_id) { > > > > > > > > - struct sctp_sock *sp = sctp_sk(sk); > > > > > > > > - > > > > > > > > - sp->ep->prsctp_enable = !!params.assoc_value; > > > > > > > > - } else { > > > > > > > > + if (sctp_style(sk, UDP) && sctp_id2assoc(sk, > > > > params.assoc_id)) > > > > > > > > > > > > > > This would allow using a non-existent assoc id on UDP-style > > > > > > > sockets > > > > to > > > > > > > set it at the socket, which is not expected. It should be more > > > > > > > like: > > > > > > > > > > > > > > + if (sctp_style(sk, UDP) && params.assoc_id) > > > > > > How do you see that to be the case? sctp_id2assoc will return NULL > > > > > > if > > > > an > > > > > > association isn't found, so the use of sctp_id2assoc should work > > > > > > just > > > > fine. > > > > > > > > > > Right, it will return NULL, and because of that it won't bail out as > > > > > it should and will adjust the socket config instead. > > > > > > > > > > > > > Oh, duh, you're absolutely right, NULL will evalutate to false there, > > > > and > > > > skip > > > > the conditional goto out; > > > > > > > > that said, It would make more sense to me to just change the sense of > > > > the > > > > second > > > > condition to !sctp_id2assoc(sk, params.assoc_id), so that we goto out > > > > if no > > > > association is found. it still seems a > > > > > > > > > That would break setting it on the socket without an assoc so far. > > > > > ok, yes, I see what xin is getting at now. The RFC indicates that the > > setsockopt method for this socket option is meant to set the prsctp enabled > > value on _future_ associations, implying that we should not operate at all > > on > > already existing associations (i.e. we should ignore the assoc_id in the > > passed > > in structure and only operate on the socket). That said, heres the entire > > text > > of the RFC section: > > > > 4.5. Socket Option for Getting and Setting the PR-SCTP Support > > (SCTP_PR_SUPPORTED) > > > > This socket option allows the enabling or disabling of the > > negotiation of PR-SCTP support for future associations. For existing > > associations, it allows one to query whether or not PR-SCTP support > > was negotiated on a particular association. > > > > Whether or not PR-SCTP is enabled by default is implementation > > specific. > > > > This socket option uses IPPROTO_SCTP as its level and > > SCTP_PR_SUPPORTED as its name. It can be used with getsockopt() and > > setsockopt(). The socket option value uses the following structure > > defined in [RFC6458]: > > > > struct sctp_assoc_value { > > sctp_assoc_t assoc_id; > > uint32_t assoc_value; > > }; > > > > assoc_id: This parameter is ignored for one-to-one style sockets. > > For one-to-many style sockets, this parameter indicates upon which > > association the user is performing an action. The special > > sctp_assoc_t SCTP_FUTURE_ASSOC can also be used; it is an error to > > use SCTP_{CURRENT|ALL}_ASSOC in assoc_id. > > > > assoc_value: A non-zero value encodes the enabling of PR-SCTP, > > whereas a value of 0 encodes the disabling of PR-SCTP. > > > > sctp_opt_info() needs to be extended to support SCTP_PR_SUPPORTED > > > > My read of this suggests that for setting the prsctp_enabled flag, we only > > need > > a valid socket (the presence or lack of associations is irrelevant), its > > only > > for the getsockopt method that we need to specify an assoc_id, as the > > getsockopt > > method operates on associations, while the setsockopt method operates at the > > socket level (to be inherited as association init). > > > > Given that, I'd argue that we can skip the check entirely, and just assign > > sctp_sock(sk)->prsctp_enabled = !!param.assoc_value > > > > directly. > RFC seems to have no clear demands for this, I will just drop the check > in this patch, thanks.
RFC may not have clear demands, but I still don't see a reason for not rejecting bogus arguments that can potentially lead to confusion. We usually do argument parsing in the other way around: restrict as much as possible, and relax when needed. That avoids applications to build bad behaviors that we would end up having to cope with it. Anyhow, I won't oppose to this any further. @Dave: please give me till Tue to review the other patches. I'm traveling and will be offline till Mon night. Thanks. Marcelo