On 11/20/2012 02:28 PM, Vlad Yasevich wrote:
On 11/20/2012 02:15 PM, Neil Horman wrote:
On Tue, Nov 20, 2012 at 01:44:23PM -0500, Vlad Yasevich wrote:
On 11/20/2012 12:59 PM, Neil Horman wrote:
In the event that an association exceeds its max_retrans attempts,
we should
send an ABORT chunk indicating that we are closing the assocation as
a result.
Because of the nature of the error, its unlikely to be received, but
its a nice
clean way to close the association if it does make it through, and
it will give
anyone watching via tcpdump a clue as to what happened.
Signed-off-by: Neil Horman <nhorman@xxxxxxxxxxxxx>
CC: Vlad Yasevich <vyasevich@xxxxxxxxx>
CC: "David S. Miller" <davem@xxxxxxxxxxxxx>
CC: linux-sctp@xxxxxxxxxxxxxxx
---
include/net/sctp/sm.h | 2 ++
net/sctp/sm_make_chunk.c | 26 +++++++++++++++++++++-----
net/sctp/sm_sideeffect.c | 9 ++++++++-
3 files changed, 31 insertions(+), 6 deletions(-)
diff --git a/include/net/sctp/sm.h b/include/net/sctp/sm.h
index b5887e1..2a82d13 100644
--- a/include/net/sctp/sm.h
+++ b/include/net/sctp/sm.h
@@ -234,6 +234,8 @@ struct sctp_chunk
*sctp_make_abort_violation(const struct sctp_association *,
struct sctp_chunk *sctp_make_violation_paramlen(const struct
sctp_association *,
const struct sctp_chunk *,
struct sctp_paramhdr *);
+struct sctp_chunk *sctp_make_violation_max_retrans(const struct
sctp_association *,
+ const struct sctp_chunk *);
struct sctp_chunk *sctp_make_heartbeat(const struct
sctp_association *,
const struct sctp_transport *);
struct sctp_chunk *sctp_make_heartbeat_ack(const struct
sctp_association *,
diff --git a/net/sctp/sm_make_chunk.c b/net/sctp/sm_make_chunk.c
index fbe1636..d6a8c80 100644
--- a/net/sctp/sm_make_chunk.c
+++ b/net/sctp/sm_make_chunk.c
@@ -1074,17 +1074,33 @@ struct sctp_chunk
*sctp_make_violation_paramlen(
{
struct sctp_chunk *retval;
static const char error[] = "The following parameter had
invalid length:";
- size_t payload_len = sizeof(error) + sizeof(sctp_errhdr_t) +
- sizeof(sctp_paramhdr_t);
+ size_t payload_len = sizeof(error) + sizeof(sctp_errhdr_t);
retval = sctp_make_abort(asoc, chunk, payload_len);
if (!retval)
goto nodata;
- sctp_init_cause(retval, SCTP_ERROR_PROTO_VIOLATION,
- sizeof(error) + sizeof(sctp_paramhdr_t));
+ sctp_init_cause(retval, SCTP_ERROR_PROTO_VIOLATION,
sizeof(error));
+ sctp_addto_chunk(retval, sizeof(error), error);
+
+nodata:
+ return retval;
+}
Neil
You ended dropping the parameter information of the parameter that
caused the violation. Was that intentional?
Yes, it was, because theres not really IMO a specific parameter that
causes this
abort condition.
Sure there is. You changed sctp_make_violation_paramlen() which is
called when we receive a protocol parameter which has an invalid length.
This triggers a violation and the parameter is report back. This has
nothing to do with max_rtx overflow.
It looks like you tried to re-use sctp_make_violation_paramlen(),
abandoned that approach, but forgot to fully restore the old function...
-vlad
The new code doesn't have to include parameter information and I am fine
with that.
-vlad
If a chunk needs to be resent more than max_retrans times, we
abort the connection, theres no specific parameter that we can point
to that
says "this caused the problem", we're just aborting because we can't
get a SACK
from the peer. Likewise, I can't think of any information that we can
include
that would give the peer, or the anyone tcpdumping the connection an
improved
view as to why the abort happened, beyond the string this patch currently
includes.
I know I had privately sent you an early version of the patch as a
rough draft
which did include space for a param header, but that patch never
filled that
space out, since we don't have any valid information to fill it out with.
Thanks & Regards
Neil
Neil
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