[PATCH net-next 21/27] sctp: add rfc6525 section 5.2.3

[Xin Long]

This patch is to implement Receiver-Side Procedures for the Incoming
SSN Reset Request Parameter described in section 5.2.3.

Signed-off-by: Xin Long <lucien....@gmail.com>
---
 include/net/sctp/sm.h |  4 ++++
 net/sctp/stream.c     | 63 +++++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 67 insertions(+)

diff --git a/include/net/sctp/sm.h b/include/net/sctp/sm.h
index 1833215..180d017 100644
--- a/include/net/sctp/sm.h
+++ b/include/net/sctp/sm.h
@@ -285,6 +285,10 @@ struct sctp_chunk *sctp_process_strreset_outreq(
                                struct sctp_association *asoc,
                                union sctp_params param,
                                struct sctp_ulpevent **evp);
+struct sctp_chunk *sctp_process_strreset_inreq(
+                               struct sctp_association *asoc,
+                               union sctp_params param,
+                               struct sctp_ulpevent **evp);
 
 /* Prototypes for statetable processing. */
 
diff --git a/net/sctp/stream.c b/net/sctp/stream.c
index 1d5b795..3053d06 100644
--- a/net/sctp/stream.c
+++ b/net/sctp/stream.c
@@ -144,3 +144,66 @@ struct sctp_chunk *sctp_process_strreset_outreq(
 out:
        return sctp_make_strreset_resp(asoc, result, request_seq);
 }
+
+struct sctp_chunk *sctp_process_strreset_inreq(
+                               struct sctp_association *asoc,
+                               union sctp_params param,
+                               struct sctp_ulpevent **evp)
+{
+       struct sctp_strreset_inreq *inreq = param.v;
+       __u32 result = SCTP_STRRESET_DENIED;
+       struct sctp_chunk *chunk = NULL;
+       __u16 i, nums, *str_p;
+       __u32 request_seq;
+
+       request_seq = ntohl(inreq->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_STREAM_REQ))
+               goto out;
+
+       if (asoc->strreset_outstanding) {
+               result = SCTP_STRRESET_ERR_IN_PROGRESS;
+               goto out;
+       }
+
+       nums = (ntohs(param.p->length) - sizeof(*inreq)) / 2;
+       str_p = inreq->list_of_streams;
+       for (i = 0; i < nums; i++) {
+               str_p[i] = ntohs(str_p[i]);
+               if (str_p[i] >= asoc->streamoutcnt) {
+                       result = SCTP_STRRESET_ERR_WRONG_SSN;
+                       goto out;
+               }
+       }
+
+       chunk = sctp_make_strreset_req(asoc, nums, str_p, 1, 0);
+       if (!chunk)
+               goto out;
+
+       if (nums)
+               for (i = 0; i < nums; i++)
+                       asoc->streamout[str_p[i]].state =
+                                                  SCTP_STREAM_CLOSED;
+       else
+               for (i = 0; i < asoc->streamoutcnt; i++)
+                       asoc->streamout[i].state = SCTP_STREAM_CLOSED;
+
+       asoc->strreset_chunk = chunk;
+       asoc->strreset_outstanding = 1;
+       sctp_chunk_hold(asoc->strreset_chunk);
+
+       *evp = sctp_ulpevent_make_stream_reset_event(asoc,
+               SCTP_STREAM_RESET_INCOMING_SSN, nums, str_p, GFP_ATOMIC);
+
+out:
+       if (!chunk)
+               chunk =  sctp_make_strreset_resp(asoc, result, request_seq);
+
+       return chunk;
+}
-- 
2.1.0