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Date: Tue, 21 Mar 2017 13:44:32 +0800
From: Xin Long <lucien.xin@...il.com>
To: Marcelo Ricardo Leitner <marcelo.leitner@...il.com>
Cc: network dev <netdev@...r.kernel.org>, linux-sctp@...r.kernel.org,
Neil Horman <nhorman@...driver.com>,
Vlad Yasevich <vyasevich@...il.com>,
davem <davem@...emloft.net>
Subject: Re: [PATCHv2 net-next 2/7] sctp: implement receiver-side procedures
for the SSN/TSN Reset Request Parameter
On Tue, Mar 21, 2017 at 2:04 AM, Marcelo Ricardo Leitner
<marcelo.leitner@...il.com> wrote:
> 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@...il.com>
>> ---
>> 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?
we can not just ignore or response with ERR.
rfc6525#section-5.2.1:
... If the received RE-CONFIG chunk contains at least
one request and based on the analysis of the Re-configuration Request
Sequence Numbers this is the last received RE-CONFIG chunk (i.e., a
retransmission), the same RE-CONFIG chunk MUST to be sent back in
response, as it was earlier.
>
>> +
>> + 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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