Re: [PATCH net] sctp: do not update transport pathmtu if SPP_PMTUD_ENABLE is not set

[Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>]

On Wed, Jul 21, 2021 at 12:08:25PM -0400, Xin Long wrote:
> Currently, in sctp_packet_config(), sctp_transport_pmtu_check() is
> called to update transport pathmtu with dst's mtu when dst's mtu
> has been changed by non sctp stack like xfrm.
> 
> However, this should only happen when SPP_PMTUD_ENABLE is set, no
> matter where dst's mtu changed. This patch is to fix by checking
> SPP_PMTUD_ENABLE flag before calling sctp_transport_pmtu_check().
> 
> Thanks Jacek for reporting and looking into this issue.
> 
> Fixes: 69fec325a643 ('Revert "sctp: remove sctp_transport_pmtu_check"')
> Reported-by: Jacek Szafraniec <jacek.szafraniec@nokia.com>
> Tested-by: Jacek Szafraniec <jacek.szafraniec@nokia.com>
> Signed-off-by: Xin Long <lucien.xin@gmail.com>
> ---
>  net/sctp/output.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/net/sctp/output.c b/net/sctp/output.c
> index 9032ce60d50e..8d5708dd2a1f 100644
> --- a/net/sctp/output.c
> +++ b/net/sctp/output.c
> @@ -104,8 +104,8 @@ void sctp_packet_config(struct sctp_packet *packet, __u32 vtag,
>  		if (asoc->param_flags & SPP_PMTUD_ENABLE)
>  			sctp_assoc_sync_pmtu(asoc);
>  	} else if (!sctp_transport_pl_enabled(tp) &&
> -		   !sctp_transport_pmtu_check(tp)) {
> -		if (asoc->param_flags & SPP_PMTUD_ENABLE)
> +		   asoc->param_flags & SPP_PMTUD_ENABLE)

Lacks a '{' here at the end of the line.

Other than that:
Acked-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>

(please add it on the v2)

> +		if (!sctp_transport_pmtu_check(tp))
>  			sctp_assoc_sync_pmtu(asoc);
>  	}
>  
> -- 
> 2.27.0
>