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authorChristian Grothoff <christian@grothoff.org>2019-04-17 22:54:14 +0200
committerChristian Grothoff <christian@grothoff.org>2019-04-17 22:54:14 +0200
commitc29a8124f885f28f287e91ce7a0dabcdd6b17d50 (patch)
treef21cc1557806c19d4b01437ab6b01538e7d9fa0d /src/transport/gnunet-service-tng.c
parentbd337cf7c6993eb8e97976ec0b088b317c57da0e (diff)
more work on route_message() logic
Diffstat (limited to 'src/transport/gnunet-service-tng.c')
-rw-r--r--src/transport/gnunet-service-tng.c193
1 files changed, 149 insertions, 44 deletions
diff --git a/src/transport/gnunet-service-tng.c b/src/transport/gnunet-service-tng.c
index f3874724a..27c97860e 100644
--- a/src/transport/gnunet-service-tng.c
+++ b/src/transport/gnunet-service-tng.c
@@ -3326,50 +3326,148 @@ queue_send_msg (struct Queue *queue,
/**
+ * Which transmission options are allowable for transmission?
+ * Interpreted bit-wise!
+ */
+enum RouteMessageOptions {
+ /**
+ * Only confirmed, non-DV direct neighbours.
+ */
+ RMO_NONE = 0,
+
+ /**
+ * We are allowed to use DV routing for this @a hdr
+ */
+ RMO_DV_ALLOWED = 1,
+
+ /**
+ * We are allowed to use unconfirmed queues or DV routes for this message
+ */
+ RMO_UNCONFIRMED_ALLOWED = 2,
+
+ /**
+ * Reliable and unreliable, DV and non-DV are all acceptable.
+ */
+ RMO_ANYTHING_GOES = (RMO_DV_ALLOWED | RMO_UNCONFIRMED_ALLOWED),
+
+ /**
+ * If we have multiple choices, it is OK to send this message
+ * over multiple channels at the same time to improve loss tolerance.
+ * (We do at most 2 transmissions.)
+ */
+ RMO_REDUNDANT = 4
+};
+
+
+/**
+ * Pick a queue of @a n under constraints @a options and schedule
+ * transmission of @a hdr.
+ *
+ * @param n neighbour to send to
+ * @param hdr message to send as payload
+ * @param options whether queues must be confirmed or not,
+ * and whether we may pick multiple (2) queues
+ */
+static void
+route_via_neighbour (const struct Neighbour *n,
+ const struct GNUNET_MessageHeader *hdr,
+ enum RouteMessageOptions options)
+{
+ // FIXME: pick on or two 'random' queue (under constraints of options)
+ // Then add wrapper and enqueue message!
+}
+
+
+/**
+ * Pick a path of @a dv under constraints @a options and schedule
+ * transmission of @a hdr.
+ *
+ * @param n neighbour to send to
+ * @param hdr message to send as payload
+ * @param options whether path must be confirmed or not
+ * and whether we may pick multiple (2) paths
+ */
+static void
+route_via_dv (const struct DistanceVector *dv,
+ const struct GNUNET_MessageHeader *hdr,
+ enum RouteMessageOptions options)
+{
+ // FIXME: pick on or two 'random' paths (under constraints of options)
+ // Then add DVBox and enqueue message (possibly using
+ // route_via_neighbour for 1st hop?)
+}
+
+
+/**
* We need to transmit @a hdr to @a target. If necessary, this may
- * involve DV routing or even broadcasting and fragmentation.
+ * involve DV routing.
*
* @param target peer to receive @a hdr
* @param hdr header of the message to route and #GNUNET_free()
+ * @param options which transmission channels are allowed
*/
static void
route_message (const struct GNUNET_PeerIdentity *target,
- struct GNUNET_MessageHeader *hdr)
-{
- // Cases:
- // 1: called to transmit backchannel message we initiated
- // 2: called to transmit fragment ack
- // 3: called to transmit reliability box
- // 4: called to forward backchannel message
- // 5: called to forward DV learn message (caller already picked random neighbour(s))!
- // 6: called to forward DV Box message
- // 7: called to forward valdiation response
-
- // Choices:
- // a) Send ONLY to a *confirmed* direct neighbour
- // b) Send allowed to *unconfirmed* direct neighbour
- // c) Route also via *confirmed* DV to target
- // c) Route allowed via *unconfirmed DV to target
- // => One BIT "dv allowed or not", plus one BIT "confirmed/unconfirmed" might do!
-
- // Case analysis:
- // 1 2 3 4 5 6 7
- // a X X X X X X X
- // b X X
- // c X X X X X
- // d X
- //
-
- // FIXME: this one is tricky:
- // - we could try a direct, reliable channel
- // - if that is unavailable / for load balancing, we may try:
- // * multiple (?) direct unreliable channels - depending on loss rate?
- // * some (?) DV channels - if above unavailable / too lossy?
- // * _random_ other peers ("broadcasting") in hope of *discovering*
- // a path back! - if all else fails
- // => need more on DV first!
-
- // FIXME: send hdr to target, free hdr (possibly using DV, possibly broadcasting)
+ struct GNUNET_MessageHeader *hdr,
+ enum RouteMessageOptions options)
+{
+ struct Neighbour *n;
+ struct DistanceVector *dv;
+
+ n = GNUNET_CONTAINER_multipeermap_get (neighbours,
+ target);
+ dv = (0 != (options & RMO_DV_ALLOWED))
+ ? GNUNET_CONTAINER_multipeermap_get (dv_routes,
+ target)
+ : NULL;
+ if (0 == (options & RMO_UNCONFIRMED_ALLOWED))
+ {
+ /* if confirmed is required, and we do not have anything
+ confirmed, drop respective options */
+ if ( (NULL != n) &&
+ (GNUNET_NO == n->core_visible) )
+ n = NULL;
+ if ( (NULL != dv) &&
+ (GNUNET_NO == dv->core_visible) )
+ dv = NULL;
+ }
+ if ( (NULL == n) &&
+ (NULL == dv) )
+ {
+ GNUNET_STATISTICS_update (GST_stats,
+ "# Messages dropped in routing: no acceptable method",
+ 1,
+ GNUNET_NO);
+ GNUNET_free (hdr);
+ return;
+ }
+ /* If both dv and n are possible and we must choose:
+ flip a coin for the choice between the two; for now 50/50 */
+ if ( (NULL != n) &&
+ (NULL != dv) &&
+ (0 == (options & RMO_REDUNDANT)) )
+ {
+ if (0 == GNUNET_CRYPTO_random_u32 (GNUNET_CRYPTO_QUALITY_WEAK, 2))
+ n = NULL;
+ else
+ dv = NULL;
+ }
+ if ( (NULL != n) &&
+ (NULL != dv) )
+ options &= ~RMO_REDUNDANT; /* We will do one DV and one direct, that's
+ enough for redunancy, so clear the flag. */
+ if (NULL != n)
+ {
+ route_via_neighbour (n,
+ hdr,
+ options);
+ }
+ if (NULL != dv)
+ {
+ route_via_dv (dv,
+ hdr,
+ options);
+ }
GNUNET_free (hdr);
}
@@ -3627,7 +3725,8 @@ handle_communicator_backchannel (void *cls,
sizeof (ppay) + ntohs (cb->header.size) - sizeof (*cb));
bc_key_clean (&key);
route_message (&cb->pid,
- &enc->header);
+ &enc->header,
+ RMO_DV_ALLOWED);
GNUNET_SERVICE_client_continue (tc->client);
}
@@ -3971,7 +4070,8 @@ send_fragment_ack (struct ReassemblyContext *rc)
ack->reassembly_timeout
= GNUNET_TIME_relative_hton (GNUNET_TIME_absolute_get_remaining (rc->reassembly_timeout));
route_message (&rc->neighbour->pid,
- &ack->header);
+ &ack->header,
+ RMO_DV_ALLOWED);
rc->avg_ack_delay = GNUNET_TIME_UNIT_ZERO;
rc->num_acks = 0;
rc->extra_acks = 0LLU;
@@ -4327,7 +4427,8 @@ handle_reliability_box (void *cls,
&rb->msg_uuid,
sizeof (struct GNUNET_ShortHashCode));
route_message (&cmc->im.sender,
- &ack->header);
+ &ack->header,
+ RMO_DV_ALLOWED);
}
/* continue with inner message */
demultiplex_with_cmc (cmc,
@@ -4470,7 +4571,8 @@ handle_backchannel_encapsulation (void *cls,
/* FIXME: BE routing can be special, should we put all of this
on 'route_message'? Maybe at least pass some more arguments? */
route_message (&be->target,
- GNUNET_copy_message (&be->header));
+ GNUNET_copy_message (&be->header),
+ RMO_DV_ALLOWED);
finish_cmc_handling (cmc);
return;
}
@@ -4818,7 +4920,8 @@ forward_dv_learn (const struct GNUNET_PeerIdentity *next_hop,
&dhops[nhops].hop_sig));
}
route_message (next_hop,
- &fwd->header);
+ &fwd->header,
+ RMO_UNCONFIRMED_ALLOWED);
}
@@ -5160,7 +5263,8 @@ forward_dv_box (struct Neighbour *next_hop,
payload,
payload_size);
route_message (&next_hop->pid,
- &dvb->header);
+ &dvb->header,
+ RMO_NONE);
}
@@ -5290,7 +5394,8 @@ handle_validation_challenge (void *cls,
&tvr->signature));
}
route_message (&cmc->im.sender,
- &tvr->header);
+ &tvr->header,
+ RMO_ANYTHING_GOES | RMO_REDUNDANT);
finish_cmc_handling (cmc);
}