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/*
* 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;
}
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