From d570a59c5b5f8fb3b65fa7b15ddb205a1d55f8d0 Mon Sep 17 00:00:00 2001 From: Xin Long Date: Sat, 25 Nov 2017 21:05:33 +0800 Subject: [PATCH] sctp: only allow the out stream reset when the stream outq is empty Now the out stream reset in sctp stream reconf could be done even if the stream outq is not empty. It means that users can not be sure since which msg the new ssn will be used. To make this more synchronous, it shouldn't allow to do out stream reset until these chunks in unsent outq all are sent out. This patch checks the corresponding stream outqs when sending and processing the request . If any of them has unsent chunks in outq, it will return -EAGAIN instead or send SCTP_STRRESET_IN_PROGRESS back to the sender. Fixes: 7f9d68ac944e ("sctp: implement sender-side procedures for SSN Reset Request Parameter") Suggested-by: Marcelo Ricardo Leitner Signed-off-by: Xin Long Acked-by: Marcelo Ricardo Leitner Signed-off-by: David S. Miller --- net/sctp/stream.c | 35 +++++++++++++++++++++++++++++++++++ 1 file changed, 35 insertions(+) diff --git a/net/sctp/stream.c b/net/sctp/stream.c index 09c797a..b209037 100644 --- a/net/sctp/stream.c +++ b/net/sctp/stream.c @@ -254,6 +254,30 @@ static int sctp_send_reconf(struct sctp_association *asoc, return retval; } +static bool sctp_stream_outq_is_empty(struct sctp_stream *stream, + __u16 str_nums, __be16 *str_list) +{ + struct sctp_association *asoc; + __u16 i; + + asoc = container_of(stream, struct sctp_association, stream); + if (!asoc->outqueue.out_qlen) + return true; + + if (!str_nums) + return false; + + for (i = 0; i < str_nums; i++) { + __u16 sid = ntohs(str_list[i]); + + if (stream->out[sid].ext && + !list_empty(&stream->out[sid].ext->outq)) + return false; + } + + return true; +} + int sctp_send_reset_streams(struct sctp_association *asoc, struct sctp_reset_streams *params) { @@ -317,6 +341,11 @@ int sctp_send_reset_streams(struct sctp_association *asoc, for (i = 0; i < str_nums; i++) nstr_list[i] = htons(str_list[i]); + if (out && !sctp_stream_outq_is_empty(stream, str_nums, nstr_list)) { + retval = -EAGAIN; + goto out; + } + chunk = sctp_make_strreset_req(asoc, str_nums, nstr_list, out, in); kfree(nstr_list); @@ -636,6 +665,12 @@ struct sctp_chunk *sctp_process_strreset_inreq( } } + if (!sctp_stream_outq_is_empty(stream, nums, str_p)) { + result = SCTP_STRRESET_IN_PROGRESS; + asoc->strreset_inseq--; + goto err; + } + chunk = sctp_make_strreset_req(asoc, nums, str_p, 1, 0); if (!chunk) goto out; -- 2.7.4