1 files changed, 227 insertions, 0 deletions
diff --git a/hicn-light/src/hicn/core/pit.c b/hicn-light/src/hicn/core/pit.c
new file mode 100644
index 000000000..fa54e2429
--- /dev/null
+++ b/hicn-light/src/hicn/core/pit.c
@@ -0,0 +1,227 @@
+/*
+ * Copyright (c) 2017-2020 Cisco and/or its affiliates.
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at:
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+/**
+ * The pending interest table.
+ *
+ * Interest aggregation strategy:
+ * - The first Interest for a name is forwarded
+ * - A second Interest for a name from a different reverse path may be
+ * aggregated
+ * - A second Interest for a name from an existing Interest is forwarded
+ * - The Interest Lifetime is like a subscription time.  A reverse path entry is
+ * removed once the lifetime is exceeded.
+ * - Whan an Interest arrives or is aggregated, the Lifetime for that reverse
+ * hop is extended.  As a simplification, we only keep a single lifetime not per
+ * reverse hop.
+ *
+ */
+
+#include <assert.h>
+#include <stdio.h>
+#define __STDC_FORMAT_MACROS
+#include <inttypes.h>
+
+#include <hicn/core/msgbuf.h>
+#include <hicn/base/pool.h>
+#include <hicn/core/ticks.h>
+#include <hicn/util/log.h>
+
+#include "pit.h"
+
+// XXX TODO Should not be defined here
+#define DEFAULT_INTEREST_LIFETIME 4000000000ULL
+
+static Ticks _pit_calculate_lifetime(pit_t * pit,
+        msgbuf_t *interest_msgbuf) {
+    uint64_t interestLifetimeTicks =
+        msgbuf_get_interest_lifetime(interest_msgbuf);
+    if (interestLifetimeTicks == 0) {
+        interestLifetimeTicks = NSEC_TO_TICKS(DEFAULT_INTEREST_LIFETIME);
+    }
+
+    Ticks expiry_time = ticks_now() + interestLifetimeTicks;
+    return expiry_time;
+}
+
+// max_elts default is 65535
+pit_t *
+pit_create(size_t max_elts)
+{
+    pit_t * pit = malloc(sizeof(pit_t));
+    if (!pit)
+        return NULL;
+
+    pool_init(pit->entries, max_elts);
+    pit->index_by_name = kh_init(pit_name);
+
+    DEBUG("PIT %p created", pit);
+
+    return pit;
+}
+
+void
+pit_free(pit_t * pit)
+{
+    assert(pit);
+    // XXX TODO
+
+    DEBUG("PIT %p destroyed", pit);
+}
+
+pit_verdict_t
+pit_on_interest(pit_t * pit, msgbuf_t * interest_msgbuf)
+{
+    assert(pit);
+    assert(interest_msgbuf);
+    assert(msgbuf_get_type(interest_msgbuf) == MESSAGE_TYPE_INTEREST);
+
+    fib_entry_t * fib_entry;
+    Ticks expiry_time;
+
+    /* Lookup entry by name */
+    khiter_t k = kh_get_pit_name(pit->index_by_name, msgbuf_get_name(interest_msgbuf));
+    if (k == kh_end(pit->index_by_name))
+        goto NOT_FOUND;
+    pit_entry_t * entry = pit->entries + kh_val(pit->index_by_name, k);
+    assert(entry);
+
+    // has it expired?
+    if (ticks_now() >= pit_entry_get_expiry_time(entry))
+        goto TIMEOUT;
+
+    /* Extend entry lifetime */
+    expiry_time = _pit_calculate_lifetime(pit, interest_msgbuf);
+    if (expiry_time > pit_entry_get_expiry_time(entry))
+        pit_entry_set_expiry_time(entry, expiry_time);
+
+    unsigned connection_id = msgbuf_get_connection_id(interest_msgbuf);
+
+    // Is the reverse path already in the PIT entry?
+    if (pit_entry_ingress_contains(entry, connection_id)) {
+        // It is already in the PIT entry, so this is a retransmission, so
+        // forward it.
+        DEBUG("Message %p existing entry (expiry %" PRIu64 ") and reverse path, forwarding",
+                    interest_msgbuf, pit_entry_get_expiry_time(entry));
+        return PIT_VERDICT_RETRANSMIT;
+    }
+
+    // It is in the PIT but this is the first interest for the reverse path
+    pit_entry_ingress_add(entry, connection_id);
+
+    DEBUG("Message %p existing entry (expiry %" PRIu64 ") and reverse path is new, aggregate",
+            interest_msgbuf, pit_entry_get_expiry_time(entry));
+    return PIT_VERDICT_AGGREGATE;
+
+TIMEOUT:
+    fib_entry = pit_entry_get_fib_entry(entry);
+    if (fib_entry)
+        fib_entry_on_timeout(fib_entry, pit_entry_get_egress(entry));
+
+    // it's an old entry, remove it
+    k = kh_get(pit_name, pit->index_by_name, msgbuf_get_name(interest_msgbuf));
+    if (k != kh_end(pit->index_by_name))
+        kh_del(pit_name, pit->index_by_name, k);
+
+NOT_FOUND:
+    /* Create PIT entry */
+
+    expiry_time = _pit_calculate_lifetime(pit, interest_msgbuf);
+
+    pit_allocate(pit, entry, interest_msgbuf);
+    pit_entry_from_msgbuf(entry, interest_msgbuf, expiry_time, ticks_now());
+
+    DEBUG("Message %p added to PIT (expiry %" PRIu64 ") ingress %u",
+            interest_msgbuf, pit_entry_get_expiry_time(entry),
+            msgbuf_get_connection_id(interest_msgbuf));
+
+    return PIT_VERDICT_FORWARD;
+}
+
+nexthops_t *
+pit_on_data(pit_t * pit, const msgbuf_t * data_msgbuf)
+{
+    assert(pit);
+    assert(data_msgbuf);
+    assert(msgbuf_get_type(data_msgbuf) == MESSAGE_TYPE_DATA);
+
+    nexthops_t * nexthops = NULL;
+
+    /* Lookup entry by name */
+    khiter_t k = kh_get_pit_name(pit->index_by_name, msgbuf_get_name(data_msgbuf));
+    if (k == kh_end(pit->index_by_name))
+        goto NOT_FOUND;
+
+    pit_entry_t * entry = pit->entries + kh_val(pit->index_by_name, k);
+    assert(entry);
+
+    // here we need to check if the PIT entry is expired
+    // if so, remove the PIT entry.
+    Ticks now = ticks_now();
+    if (now >= pit_entry_get_expiry_time(entry))
+        goto TIMEOUT;
+
+    /* PIT entry is not expired, use it */
+    fib_entry_t * fib_entry = pit_entry_get_fib_entry(entry);
+    if (fib_entry)
+        fib_entry_on_data(fib_entry, pit_entry_get_egress(entry),
+                data_msgbuf, pit_entry_get_creation_time(entry), ticks_now());
+
+    // XXX TODO : be sure nexthops are valid b/c pit entry is removed
+    // XXX TODO eventually pass holding structure as parameter
+    nexthops = pit_entry_get_ingress(entry);
+
+TIMEOUT:
+    /* Remove entry from PIT */
+    kh_del(pit_name, pit->index_by_name, k);
+
+NOT_FOUND:
+    return nexthops;
+}
+
+void
+pit_remove(pit_t * pit, const msgbuf_t * interest_msgbuf)
+{
+    assert(pit);
+    assert(interest_msgbuf);
+    assert(msgbuf_get_type(interest_msgbuf) == MESSAGE_TYPE_INTEREST);
+
+    khiter_t k = kh_get(pit_name, pit->index_by_name, msgbuf_get_name(interest_msgbuf));
+    if (k == kh_end(pit->index_by_name))
+        return;
+    //off_t index = kh_val(pit->index_by_name, k);
+    //pit_entry_t * entry = pit_at(pit, index);
+    kh_del(pit_name, pit->index_by_name, k);
+
+    DEBUG("Message %p removed from PIT", interest_msgbuf);
+}
+
+pit_entry_t *
+pit_lookup(const pit_t * pit, const msgbuf_t * interest_msgbuf)
+{
+    assert(pit);
+    assert(interest_msgbuf);
+    assert(msgbuf_get_type(interest_msgbuf) == MESSAGE_TYPE_INTEREST);
+
+    khiter_t k = kh_get(pit_name, pit->index_by_name,
+            msgbuf_get_name(interest_msgbuf));
+    if (k == kh_end(pit->index_by_name))
+        return NULL;
+    off_t index = kh_val(pit->index_by_name, k);
+    pit_entry_t * entry = pit_at(pit, index);
+    assert(entry);
+
+    return entry;
+}