From 692787cef6515188f25a5b6cdf008cfe10acf89f Mon Sep 17 00:00:00 2001 From: Xin Long Date: Fri, 10 Mar 2017 12:11:07 +0800 Subject: 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 Signed-off-by: David S. Miller --- net/sctp/stream.c | 79 +++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 79 insertions(+) (limited to 'net/sctp/stream.c') diff --git a/net/sctp/stream.c b/net/sctp/stream.c index 1c6cc04fa3a4..7e993b0c1412 100644 --- a/net/sctp/stream.c +++ b/net/sctp/stream.c @@ -477,3 +477,82 @@ out: 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++; + } + + 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); +} -- cgit