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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>
zero-colors
Xin Long 2017-03-10 12:11:07 +08:00 committed by David S. Miller
parent c95129d127
commit 692787cef6
3 changed files with 86 additions and 0 deletions
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4
include/net/sctp/sm.h
View File

@ -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. */

3
net/sctp/sm_statefuns.c
View File

@ -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.
*/

79
net/sctp/stream.c
View File

@ -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);
}