Hi Richard,
On Mon, Nov 27, 2017 at 07:31:21PM +0000, Richard Haines wrote:
...
> --- a/net/sctp/socket.c
> +++ b/net/sctp/socket.c
> @@ -3123,8 +3123,10 @@ static int sctp_setsockopt_maxseg(struct sock *sk,
> char __user *optval, unsigned
>
> if (asoc) {
> if (val == 0) {
> + struct sctp_af *af = sp->pf->af;
> val = asoc->pathmtu;
> - val -= sp->pf->af->net_header_len;
> + val -= af->ip_options_len(asoc->base.sk);
> + val -= af->net_header_len;
> val -= sizeof(struct sctphdr) +
> sizeof(struct sctp_data_chunk);
> }
Right below here there is a call to sctp_frag_point(). That function
also needs this tweak.
Yes, we should simplify all these calculations. I have a patch to use
sctp_frag_point on where it is currently recalculating it on
sctp_datamsg_from_user(), but probably should include other places as
well.
Marcelo
