On Fri, Mar 10, 2017 at 12:11:07PM +0800, Xin Long wrote:
> This patch is to implement Receiver-Side Procedures for the SSN/TSN
> Reset Request Parameter described in rfc6525 section 6.2.4.
>
> The process is kind of complicate, it's wonth having some comments
> from section 6.2.4 in the codes.
>
> Signed-off-by: Xin Long <lucien.xin@xxxxxxxxx>
> ---
> include/net/sctp/sm.h | 4 +++
> net/sctp/sm_statefuns.c | 3 ++
> net/sctp/stream.c | 79 +++++++++++++++++++++++++++++++++++++++++++++++++
> 3 files changed, 86 insertions(+)
>
> diff --git a/include/net/sctp/sm.h b/include/net/sctp/sm.h
> index b6f682e..2629d66 100644
> --- a/include/net/sctp/sm.h
> +++ b/include/net/sctp/sm.h
> @@ -293,6 +293,10 @@ struct sctp_chunk *sctp_process_strreset_inreq(
> struct sctp_association *asoc,
> union sctp_params param,
> struct sctp_ulpevent **evp);
> +struct sctp_chunk *sctp_process_strreset_tsnreq(
> + struct sctp_association *asoc,
> + union sctp_params param,
> + struct sctp_ulpevent **evp);
>
> /* Prototypes for statetable processing. */
>
> diff --git a/net/sctp/sm_statefuns.c b/net/sctp/sm_statefuns.c
> index e03bb1a..6982064 100644
> --- a/net/sctp/sm_statefuns.c
> +++ b/net/sctp/sm_statefuns.c
> @@ -3872,6 +3872,9 @@ sctp_disposition_t sctp_sf_do_reconf(struct net *net,
> else if (param.p->type == SCTP_PARAM_RESET_IN_REQUEST)
> reply = sctp_process_strreset_inreq(
> (struct sctp_association *)asoc, param, &ev);
> + else if (param.p->type == SCTP_PARAM_RESET_TSN_REQUEST)
> + reply = sctp_process_strreset_tsnreq(
> + (struct sctp_association *)asoc, param, &ev);
> /* More handles for other types will be added here, by now it
> * just ignores other types.
> */
> diff --git a/net/sctp/stream.c b/net/sctp/stream.c
> index 1c6cc04..7e993b0 100644
> --- a/net/sctp/stream.c
> +++ b/net/sctp/stream.c
> @@ -477,3 +477,82 @@ struct sctp_chunk *sctp_process_strreset_inreq(
>
> return chunk;
> }
> +
> +struct sctp_chunk *sctp_process_strreset_tsnreq(
> + struct sctp_association *asoc,
> + union sctp_params param,
> + struct sctp_ulpevent **evp)
> +{
> + __u32 init_tsn = 0, next_tsn = 0, max_tsn_seen;
> + struct sctp_strreset_tsnreq *tsnreq = param.v;
> + struct sctp_stream *stream = asoc->stream;
> + __u32 result = SCTP_STRRESET_DENIED;
> + __u32 request_seq;
> + __u16 i;
> +
> + request_seq = ntohl(tsnreq->request_seq);
> + if (request_seq > asoc->strreset_inseq) {
> + result = SCTP_STRRESET_ERR_BAD_SEQNO;
> + goto out;
> + } else if (request_seq == asoc->strreset_inseq) {
> + asoc->strreset_inseq++;
> + }
I guess I already asked this, but.. why request_seq <
asoc->strreset_inseq is allowed?
> +
> + if (!(asoc->strreset_enable & SCTP_ENABLE_RESET_ASSOC_REQ))
> + goto out;
> +
> + if (asoc->strreset_outstanding) {
> + result = SCTP_STRRESET_ERR_IN_PROGRESS;
> + goto out;
> + }
> +
> + /* G3: The same processing as though a SACK chunk with no gap report
> + * and a cumulative TSN ACK of the Sender's Next TSN minus 1 were
> + * received MUST be performed.
> + */
> + max_tsn_seen = sctp_tsnmap_get_max_tsn_seen(&asoc->peer.tsn_map);
> + sctp_ulpq_reasm_flushtsn(&asoc->ulpq, max_tsn_seen);
> + sctp_ulpq_abort_pd(&asoc->ulpq, GFP_ATOMIC);
> +
> + /* G1: Compute an appropriate value for the Receiver's Next TSN -- the
> + * TSN that the peer should use to send the next DATA chunk. The
> + * value SHOULD be the smallest TSN not acknowledged by the
> + * receiver of the request plus 2^31.
> + */
> + init_tsn = sctp_tsnmap_get_ctsn(&asoc->peer.tsn_map) + (1 << 31);
> + sctp_tsnmap_init(&asoc->peer.tsn_map, SCTP_TSN_MAP_INITIAL,
> + init_tsn, GFP_ATOMIC);
> +
> + /* G4: The same processing as though a FWD-TSN chunk (as defined in
> + * [RFC3758]) with all streams affected and a new cumulative TSN
> + * ACK of the Receiver's Next TSN minus 1 were received MUST be
> + * performed.
> + */
> + sctp_outq_free(&asoc->outqueue);
> +
> + /* G2: Compute an appropriate value for the local endpoint's next TSN,
> + * i.e., the next TSN assigned by the receiver of the SSN/TSN reset
> + * chunk. The value SHOULD be the highest TSN sent by the receiver
> + * of the request plus 1.
> + */
> + next_tsn = asoc->next_tsn;
> + asoc->ctsn_ack_point = next_tsn - 1;
> + asoc->adv_peer_ack_point = asoc->ctsn_ack_point;
> +
> + /* G5: The next expected and outgoing SSNs MUST be reset to 0 for all
> + * incoming and outgoing streams.
> + */
> + for (i = 0; i < stream->outcnt; i++)
> + stream->out[i].ssn = 0;
> + for (i = 0; i < stream->incnt; i++)
> + stream->in[i].ssn = 0;
> +
> + result = SCTP_STRRESET_PERFORMED;
> +
> + *evp = sctp_ulpevent_make_assoc_reset_event(asoc, 0, init_tsn,
> + next_tsn, GFP_ATOMIC);
> +
> +out:
> + return sctp_make_strreset_tsnresp(asoc, result, request_seq,
> + next_tsn, init_tsn);
> +}
> --
> 2.1.0
>
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