sctp: implement receiver-side procedures for the SSN/TSN Reset Request Parameter
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@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
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@ -293,6 +293,10 @@ struct sctp_chunk *sctp_process_strreset_inreq(
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struct sctp_association *asoc,
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union sctp_params param,
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struct sctp_ulpevent **evp);
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struct sctp_chunk *sctp_process_strreset_tsnreq(
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struct sctp_association *asoc,
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union sctp_params param,
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struct sctp_ulpevent **evp);
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/* Prototypes for statetable processing. */
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@ -3872,6 +3872,9 @@ sctp_disposition_t sctp_sf_do_reconf(struct net *net,
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else if (param.p->type == SCTP_PARAM_RESET_IN_REQUEST)
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reply = sctp_process_strreset_inreq(
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(struct sctp_association *)asoc, param, &ev);
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else if (param.p->type == SCTP_PARAM_RESET_TSN_REQUEST)
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reply = sctp_process_strreset_tsnreq(
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(struct sctp_association *)asoc, param, &ev);
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/* More handles for other types will be added here, by now it
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* just ignores other types.
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*/
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@ -477,3 +477,82 @@ struct sctp_chunk *sctp_process_strreset_inreq(
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return chunk;
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}
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struct sctp_chunk *sctp_process_strreset_tsnreq(
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struct sctp_association *asoc,
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union sctp_params param,
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struct sctp_ulpevent **evp)
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{
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__u32 init_tsn = 0, next_tsn = 0, max_tsn_seen;
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struct sctp_strreset_tsnreq *tsnreq = param.v;
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struct sctp_stream *stream = asoc->stream;
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__u32 result = SCTP_STRRESET_DENIED;
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__u32 request_seq;
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__u16 i;
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request_seq = ntohl(tsnreq->request_seq);
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if (request_seq > asoc->strreset_inseq) {
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result = SCTP_STRRESET_ERR_BAD_SEQNO;
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goto out;
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} else if (request_seq == asoc->strreset_inseq) {
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asoc->strreset_inseq++;
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}
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if (!(asoc->strreset_enable & SCTP_ENABLE_RESET_ASSOC_REQ))
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goto out;
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if (asoc->strreset_outstanding) {
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result = SCTP_STRRESET_ERR_IN_PROGRESS;
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goto out;
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}
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/* G3: The same processing as though a SACK chunk with no gap report
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* and a cumulative TSN ACK of the Sender's Next TSN minus 1 were
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* received MUST be performed.
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*/
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max_tsn_seen = sctp_tsnmap_get_max_tsn_seen(&asoc->peer.tsn_map);
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sctp_ulpq_reasm_flushtsn(&asoc->ulpq, max_tsn_seen);
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sctp_ulpq_abort_pd(&asoc->ulpq, GFP_ATOMIC);
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/* G1: Compute an appropriate value for the Receiver's Next TSN -- the
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* TSN that the peer should use to send the next DATA chunk. The
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* value SHOULD be the smallest TSN not acknowledged by the
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* receiver of the request plus 2^31.
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*/
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init_tsn = sctp_tsnmap_get_ctsn(&asoc->peer.tsn_map) + (1 << 31);
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sctp_tsnmap_init(&asoc->peer.tsn_map, SCTP_TSN_MAP_INITIAL,
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init_tsn, GFP_ATOMIC);
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/* G4: The same processing as though a FWD-TSN chunk (as defined in
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* [RFC3758]) with all streams affected and a new cumulative TSN
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* ACK of the Receiver's Next TSN minus 1 were received MUST be
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* performed.
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*/
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sctp_outq_free(&asoc->outqueue);
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/* G2: Compute an appropriate value for the local endpoint's next TSN,
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* i.e., the next TSN assigned by the receiver of the SSN/TSN reset
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* chunk. The value SHOULD be the highest TSN sent by the receiver
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* of the request plus 1.
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*/
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next_tsn = asoc->next_tsn;
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asoc->ctsn_ack_point = next_tsn - 1;
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asoc->adv_peer_ack_point = asoc->ctsn_ack_point;
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/* G5: The next expected and outgoing SSNs MUST be reset to 0 for all
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* incoming and outgoing streams.
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*/
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for (i = 0; i < stream->outcnt; i++)
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stream->out[i].ssn = 0;
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for (i = 0; i < stream->incnt; i++)
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stream->in[i].ssn = 0;
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result = SCTP_STRRESET_PERFORMED;
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*evp = sctp_ulpevent_make_assoc_reset_event(asoc, 0, init_tsn,
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next_tsn, GFP_ATOMIC);
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out:
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return sctp_make_strreset_tsnresp(asoc, result, request_seq,
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next_tsn, init_tsn);
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}
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