Miguel París authored Nov 08, 2017 and Olivier Crête committed Nov 28, 2017

One or more streams might not have any connection check list if the
number of streams differs from the peer agent.
Differential Revision: https://phabricator.freedesktop.org/D1880

Fabrice Bellet authored Nov 23, 2017 and Olivier Crête committed Nov 27, 2017

Differential Revision: https://phabricator.freedesktop.org/D1888

Fabrice Bellet authored Nov 21, 2017 and Olivier Crête committed Nov 27, 2017

With this patch, we stash the controlling mode property change, and
apply it safely, when it won't interfere with an ongoing conncheck
running. According to RFC5245, sect 5.2. "Determining Role", the role
is determined for a session, and persists unless an ICE is restarted.

Differential Revision: https://phabricator.freedesktop.org/D1887

https://phabricator.freedesktop.org/T7798



Signed-off-by: Philip Withnall <withnall@endlessm.com>
Reviewed-by: Olivier Crête <olivier.crete@collabora.com>
Differential Revision: https://phabricator.freedesktop.org/D1819

Spotted by Lukas Gradl on the mailing list.

Signed-off-by: Philip Withnall <withnall@endlessm.com>

This code is not 1000 years old.

Signed-off-by: Philip Withnall <withnall@endlessm.com>

Fabrice Bellet authored Jul 02, 2017 and Olivier Crête committed Sep 05, 2017

When a pair is nominated while in state failed, we first move
back to state connecting, then we update the selected pair, and
finally we move to state connected.

Fabrice Bellet authored Jun 28, 2017 and Olivier Crête committed Sep 05, 2017

When a new pair is created from an unknown remote candidate, it
should be enqueue for a triggered check, to allow it to be marked
as nominated on response arrival in priv_mark_pair_nominated().
Creating it in waiting state is not sufficient since the update
in priv_mark_pair_nominated() from previous commits.

Differential Revision: https://phabricator.freedesktop.org/D1763

Fabrice Bellet authored Jun 27, 2017 and Olivier Crête committed Sep 05, 2017

With this patch, we fix an ambiguity of some parts of the spec, when
the document refers to in-progress pairs, that also concern pairs in
the triggered checks list.

The first cast is in section 7.1.2.5, "Updating the Nominated Flag",
when the in-progress pair will be nominated on response arrival. This is
handled in function priv_mark_pair_nominated(), when a pair is put to
the triggered check list in reaction to a matching inbound stun request.
Such a pair in priv_mark_pair_nominated() will _always_ be in the
triggered check list, from the previously called function
priv_schedule_triggered_check().

The second case is in section 8.1.2, "Updating State" when an in-progress
pair stops its retransmission when another pair of higher priority is
already nominated. This is handled by function priv_prune_pending_checks().

Until now, pairs enqueued in the triggered check list move transiently
to state waiting, according to 7.2.1.4. But this state causes wrong
decisions in the two previous cases, because such pairs should in fact
rather be considered "like in-progress", to avoid discarding them
inadvertantly.

This patch update the state of the triggered check list
pairs to in-progress. It allows to remove exception handling cited
above: the code is a bit more simple, and allows some refactoring
in priv_mark_pair_nominated() between RFC and compatibility modes.

Differential Revision: https://phabricator.freedesktop.org/D1762

Fabrice Bellet authored Jun 26, 2017 and Olivier Crête committed Sep 05, 2017

This patch should improve the reliabily of the connection check by
keeping the record of several simultaneous ongoing stun requests per
pair. A new stun request on an in-progress pair typically is caused by
in inbound stun request from the peer on this same pair. This is named
"Triggered Checks" in the spec. When this situation arises, it is fair
to handle these two stun requests simultaneously, the triggered check,
and the initial ordinary check, since both can potentially succeed.

Differential Revision: https://phabricator.freedesktop.org/D1761

Fabrice Bellet authored Jun 26, 2017 and Olivier Crête committed Sep 05, 2017

We try to use stun_timer_remainder() less frequently, particularily
in the debug messages, and favour of the next_tick value associated
to the pair.

Differential Revision: https://phabricator.freedesktop.org/D1760

Fabrice Bellet authored Jun 26, 2017 and Olivier Crête committed Sep 05, 2017

We add a helper function to print the pair state in-extenso.

Differential Revision: https://phabricator.freedesktop.org/D1759

Fabrice Bellet authored Jun 26, 2017 and Olivier Crête committed Sep 05, 2017

With this patch we simplify the levels of code indentation.

Differential Revision: https://phabricator.freedesktop.org/D1758

Fabrice Bellet authored Apr 12, 2016 and Olivier Crête committed Jun 22, 2017

This patch displays explicitely the controlling or controlled
role of the agent.

Differential Revision: https://phabricator.freedesktop.org/D874

Creates useless warnings when other libraries change.

https://phabricator.freedesktop.org/T7770

GClosures are not that cheap to setup

This makes it easier to read and more extensible.

Fabrice Bellet authored Jun 18, 2017 and Olivier Crête committed Jun 21, 2017

Differential Revision: https://phabricator.freedesktop.org/D1756

Fabrice Bellet authored May 28, 2017 and Olivier Crête committed Jun 21, 2017

Differential Revision: https://phabricator.freedesktop.org/D1754

Fabrice Bellet authored Jul 15, 2016 and Olivier Crête committed Jun 21, 2017

At the end of the local candidate gathering process, we only create new
pairs for streams that are in gathering state.

Other stream that may be in ready state for example, due to a
previously succeeded conncheck process, may have accumulated some
couples (local,remote) candidates that have not resulted in the creation
a new pair during this previous conncheck process, and we don't want
these new pairs to be added now, because it would generate unneeded
transition changes for a stream unconcerned by this gathering.

Differential Revision: https://phabricator.freedesktop.org/D1755

Fabrice Bellet authored Jun 21, 2016 and Olivier Crête committed Jun 21, 2017

This patch fixes the transition of a component from connecting to
failed, that previously occured due to the propagation of the
keep_timer_going variable, and to the final call to function
priv_update_check_list_failed_components(), after the global agent
timer was stopped.

Previously, the code almost never entered to failed state, because the
timer was going one, as long as the number of nominated pair was not
enough, and as long as there were valid pairs not yet nominated. Even
if all pair timers were over.

The definition of the Failed state of a conncheck list is somewhat
contradictory in the spec, depending on weather you read :

 * sect 5.7.4. "Computing States",
 "Failed:  In this state, the ICE checks have not completed successfully
 for this media stream."

 or

 * sect 7.1.3.3. "Check List and Timer State Updates",
 "If all of the pairs in the check list are now either in the Failed or
 Succeeded state: If there is not a pair in the valid list for each
 component of the media stream, the state of the check list is set to
 Failed."

Our understanding of the ICE spec is that, the proper way to enter failed
state instead in when all connchecks have no longer in-progress pairs.
All pairs are either in state succeeded, discovered, or failed. No timer
is still running, and we have no hope that the conncheck list changes
again, except if an unexpected STUN packet arrives later. All pairs in
frozen state is a special case, that is handled separately (sect
7.1.3.3).

A special grace delay is added before declaring a component in state
Failed. This delay is not part of the RFC, and it is aimed to limit the
cases when a conncheck list is reactivated just after it's been declared
failed, causing a user visible transition from connecting to failed, and
back from failed to connecting again. This is also required by the test
suite, that counts exactly the number of time each state is entered, and
doesn't expect these transcient failed states to happen (frequent due to
the nature of the testsuite, less frequent in real life).

Differential Revision: https://phabricator.freedesktop.org/D1111

Fabrice Bellet authored Jun 16, 2016 and Olivier Crête committed Jun 21, 2017

Pairs with the state NICE_CHECK_CANCELLED are the pairs targeted for
removal after the nomination of a pair with an higher priority,
described in Section 8.1.2 "Updating States", item 2 of RFC 5245. They
include also pairs that overflow the conncheck list size, but this is a
somewhat more marginal situation. So we are mainly interested in the
first use case of this state.

This state mixes two different situations, that deserve a distinct
handling : on one side, there are waiting or frozen pairs that must be
removed, this is an immediate action that doesn't need a dedicated state
for that. And on the other side, there are in-progress pairs that
should no longer be retransmitted, because another pair with a higher
priority has already been nominated.

This patch removes the cancelled state, and adds a flag
retransmit_on_timeout to deal with this last situation. Note that this
case should not generate a triggered check, as per described in section
7.2.1.4, when the state of the pair is In-Progress or Failed, since this
pair of lower priority has no hope to replace the nominated one.

Differential Revision: https://phabricator.freedesktop.org/D1114

Fabrice Bellet authored Jun 14, 2016 and Olivier Crête committed Jun 21, 2017

The pair recheck on timeout can easily cause repetitive rechecks in
a ping-pong effect, if both peers with the same behaviour try to
check the same pair almost simultaneously, and if the network rtt
is greater than the initial timer rto. The reply to the initial
stun request may arrive after the in-progress conncheck
cancellation (described in RFC 5245, sect 7.2.1.4). Cancellation
creates a new stun request, and forgets the initial one.
The conncheck timer is restarted with the same initial value,
so the same situation happens again later.

We choose to avoid resetting the timer in such situation. After enough
retransmissions, the timeout delay, that doubles after each timeout,
becomes longer than the rtt, and the stun reply can be handled.

Differential Revision: https://phabricator.freedesktop.org/D1115

Fabrice Bellet authored Jun 14, 2016 and Olivier Crête committed Jun 21, 2017

We cancel the potential in-progress transaction cancellation, caused by
sect 7.2.1.4 "Triggered Checks", when we receive a valid reply before
transmission timeout, or just after timeout, when the pair is
temporarily put on the triggered check list on the way to be
rechecked. This situation is not covered by the RFC 5245.

Differential Revision: https://phabricator.freedesktop.org/D1119

Fabrice Bellet authored Jun 14, 2016 and Olivier Crête committed Jun 21, 2017

When a new stun request hits a valid pair, of a failed component, we may
have a transition from state failed to connected. In this situation, we
do a logical progression failed -> connecting -> connected, like we do
in function priv_update_check_list_state_for_ready()

Similarily, when a new stun request hits a failed pair, of a failed
component, triggering a new conncheck for this pair may also cause the
component state to move back from failed to connecting state.

Differential Revision: https://phabricator.freedesktop.org/D1118

Fabrice Bellet authored Jun 14, 2016 and Olivier Crête committed Jun 21, 2017

We check if we can move from state connected to ready just
after a pair expired its retransmission count. This pair
will be marked failed, and will no longer be in-progress.
The number of in-progress dropping down to zero is one
of the conditions needed to make the transition to ready,
per component (and not globally as it's the case in other
locations where this check function is called).

Differential Revision: https://phabricator.freedesktop.org/D1117

Fabrice Bellet authored Apr 11, 2016 and Olivier Crête committed Jun 21, 2017

This patch adds another supplementary "corner" case, not covered by the
ICE spec, sect 8.1.2, "Updating States". A pair in waiting state and in
the triggered check list should be considered like an in-progress pair,
and cancelled only if its priority is lower than the priority of the
nominated pair. This is required in some aggressive nomination
situations for both peers to select the same pair, having the highest
priority.

Differential Revision: https://phabricator.freedesktop.org/D933

Fabrice Bellet authored Apr 01, 2016 and Olivier Crête committed Jun 21, 2017

This exception to the ICE spec is no longer needed: when a pair is in
the succeeded state, there is no needed to recheck it again upon
reception of an incoming stun request on it.

Differential Revision: https://phabricator.freedesktop.org/D884

Fabrice Bellet authored Apr 12, 2016 and Olivier Crête committed Jun 21, 2017

With this patch, we update the state of the pair to waiting when
it is put in the triggered check queue. We also take care to call
priv_schedule_triggered_check() before priv_mark_pair_nominated()
so a pair to be rechecked and put on the triggered check queue
will have a unique state to be tested in the following call to
priv_mark_pair_nominated() when evaluating its nomination attributes.

Differential Revision: https://phabricator.freedesktop.org/D883

Fabrice Bellet authored Apr 12, 2016 and Olivier Crête committed Jun 21, 2017

This patch disables the possibility to set the nominated flag of a
candidate pair at creation time. This possibility was used when a new
pair is created from a new peer reflexive remote candidate, when the
agent is in controlled mode, and an stun request with USE-CANDIDATE is
received. In this case, since previous commit "conncheck: fix a
nomination corner case", we set the nominated flag when the stun
response of this new pair will arrive, and not before.  Consequently,
this flag is no longer required when the pair is created.

Differential Revision: https://phabricator.freedesktop.org/D881

Fabrice Bellet authored Apr 12, 2016 and Olivier Crête committed Jun 21, 2017

This patch add two supplementary cases, not covered by the ICE spec,
sect 7.2.1.5 "Updating the Nominated Flag" when a controlled agent
receives a STUN request with the USE-CANDIDATE flag, for a pair that is
in the waiting state. We consider that this case is similar to the
in-progress state, and should be handled in the same way. We also accept
when the pair is in frozen state. This latter case happens in the
new-dribble test, when an agent replays incoming early connchecks.

Differential Revision: https://phabricator.freedesktop.org/D880

Fabrice Bellet authored Apr 19, 2016 and Olivier Crête committed Jun 21, 2017

This patch completes the previous patch by adding a link back from the
discovered pair, to the parent pair that generated this check. This link
is needed by the ICE spec, to comply with section 8.1.1.1, "Regular
nomination", where the check to be retriggered is the initial check that
caused the discovery of the valid pair. When the valid pair is a
peer-reflexive pair, the retriggered check must target the succeeded
pair, and not the valid discovered pair.

Differential Revision: https://phabricator.freedesktop.org/D879

Fabrice Bellet authored Apr 12, 2016 and Olivier Crête committed Jun 21, 2017

When the agent has the role of the stun server, is in controlled mode,
and receives a pair with the "use-candidate" attribute set, it must find
a matching succeded or discovered pair in its conncheck list. This is
described in ICE spec 7.2.1.5, "Updating the Nominated Flag", item #1.
When a matching pair is in succeeded state, the agent must nominate the
valid pair (a discovered pair) constructed from section 7.1.3.2.2,
that's been created from this succeeded one. To make this lookup, we
introduce a new "discovered_pair" member of the CandidateCheckPair
struct, that links the succeeded pair, and its discovered pair
if any.

Differential Revision: https://phabricator.freedesktop.org/D878

Fabrice Bellet authored Apr 19, 2016 and Olivier Crête committed Jun 21, 2017

This patch update the way triggered checks of in-progress pairs are
handled, according to ICE spec, section 7.2.1.4. Previously the same
connection check was retransmitted with an updated timeout. This causes
problems when a controlling role switch occurs in this time frame.
This is the reason why a new connection check must be generated
reflecting the updated role. We introduce a new flag "recheck_on_timeout"
in the pair indicating that the pair must be rechecked at the next timer
expiration.

Differential Revision: https://phabricator.freedesktop.org/D875

Differential Revision: https://phabricator.freedesktop.org/D1123

This patch aims to implement more closely the algorithm described
in RFC 5245 indicating how pairs are transitionned from state Frozen
to Waiting. This is described in 7.1.3.2 when a check succeeded, and
correspond to modifications in function priv_conn_check_unfreeze_related().
This is also described in 5.7.4 when defining the initial state of the
pairs in a conncheck, and correspond to modifications in function
priv_conn_check_unfreeze_next().

This patch introduces the notion of active and frozen check list. It
allows us to define the timer restranmission delay as described in 16.1.

Another modification in priv_conn_check_tick_unlocked() is that every
stream in handled consecutively, and in an independant way. The pacing
was previously of a single STUN request emitted per callback, it is now
of a triggered check per callback OR a single STUN per callback AND per
stream per callback.

The description of ordinary checks per stream in 5.8 is detailled in
function priv_conn_check_tick_stream(), and a remaining of the code
used to nominate a pair by the controlling agent is put in a dedicated
function priv_conn_check_tick_stream_nominate()

Differential Revision: https://phabricator.freedesktop.org/D813

With this patch, we fix a corner case when the succeeded pair is a
peer-reflexive candidate pair, that already has been discovered
previously, In this case, the current pair -p- should not be marked
valid, because the valid flag is already set on the discovered pair.

Differential Revision: https://phabricator.freedesktop.org/D1124