openssl/test/quic_cc_test.c

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/*
* Copyright 2022-2023 The OpenSSL Project Authors. All Rights Reserved.
*
* Licensed under the Apache License 2.0 (the "License"). You may not use
* this file except in compliance with the License. You can obtain a copy
* in the file LICENSE in the source distribution or at
* https://www.openssl.org/source/license.html
*/
/* For generating debug statistics during congestion controller development. */
/*#define GENERATE_LOG*/
#include "testutil.h"
#include <openssl/ssl.h>
#include "internal/quic_cc.h"
#include "internal/priority_queue.h"
/*
* Time Simulation
* ===============
*/
static OSSL_TIME fake_time = {0};
#define TIME_BASE (ossl_ticks2time(5 * OSSL_TIME_SECOND))
static OSSL_TIME fake_now(void *arg)
{
return fake_time;
}
static void step_time(uint32_t ms)
{
fake_time = ossl_time_add(fake_time, ossl_ms2time(ms));
}
/*
* Network Simulation
* ==================
*
* This is a simple 'network simulator' which emulates a network with a certain
* bandwidth and latency. Sending a packet into the network causes it to consume
* some capacity of the network until the packet exits the network. Note that
* the capacity is not known to the congestion controller as the entire point of
* a congestion controller is to correctly estimate this capacity and this is
* what we are testing. The network simulator does take care of informing the
* congestion controller of ack/loss events automatically but the caller is
* responsible for querying the congestion controller and choosing the size of
* simulated transmitted packets.
*/
typedef struct net_pkt_st {
/*
* The time at which the packet was sent.
*/
OSSL_TIME tx_time;
/*
* The time at which the simulated packet arrives at the RX side (success)
* or is dropped (!success).
*/
OSSL_TIME arrive_time;
/*
* The time at which the transmitting side makes a determination of
* acknowledgement (if success) or loss (if !success).
*/
OSSL_TIME determination_time;
/*
* Current earliest time there is something to be done for this packet.
* min(arrive_time, determination_time).
*/
OSSL_TIME next_time;
/* 1 if the packet will be successfully delivered, 0 if it is to be lost. */
int success;
/* 1 if we have already processed packet arrival. */
int arrived;
/* Size of simulated packet in bytes. */
size_t size;
/* pqueue internal index. */
size_t idx;
} NET_PKT;
DEFINE_PRIORITY_QUEUE_OF(NET_PKT);
static int net_pkt_cmp(const NET_PKT *a, const NET_PKT *b)
{
return ossl_time_compare(a->next_time, b->next_time);
}
struct net_sim {
const OSSL_CC_METHOD *ccm;
OSSL_CC_DATA *cc;
uint64_t capacity; /* bytes/s */
uint64_t latency; /* ms */
uint64_t spare_capacity;
PRIORITY_QUEUE_OF(NET_PKT) *pkts;
uint64_t total_acked, total_lost; /* bytes */
};
static int net_sim_init(struct net_sim *s,
const OSSL_CC_METHOD *ccm, OSSL_CC_DATA *cc,
uint64_t capacity, uint64_t latency)
{
s->ccm = ccm;
s->cc = cc;
s->capacity = capacity;
s->latency = latency;
s->spare_capacity = capacity;
s->total_acked = 0;
s->total_lost = 0;
if (!TEST_ptr(s->pkts = ossl_pqueue_NET_PKT_new(net_pkt_cmp)))
return 0;
return 1;
}
static void do_free(NET_PKT *pkt)
{
OPENSSL_free(pkt);
}
static void net_sim_cleanup(struct net_sim *s)
{
ossl_pqueue_NET_PKT_pop_free(s->pkts, do_free);
}
static int net_sim_process(struct net_sim *s, size_t skip_forward);
static int net_sim_send(struct net_sim *s, size_t sz)
{
NET_PKT *pkt = OPENSSL_zalloc(sizeof(*pkt));
int success;
if (!TEST_ptr(pkt))
return 0;
/*
* Ensure we have processed any events which have come due as these might
* increase our spare capacity.
*/
if (!TEST_true(net_sim_process(s, 0)))
goto err;
/* Do we have room for the packet in the network? */
success = (sz <= s->spare_capacity);
pkt->tx_time = fake_time;
pkt->success = success;
if (success) {
/* This packet will arrive successfully after |latency| time. */
pkt->arrive_time = ossl_time_add(pkt->tx_time,
ossl_ms2time(s->latency));
/* Assume all received packets are acknowledged immediately. */
pkt->determination_time = ossl_time_add(pkt->arrive_time,
ossl_ms2time(s->latency));
pkt->next_time = pkt->arrive_time;
s->spare_capacity -= sz;
} else {
/*
* In our network model, assume all packets are dropped due to a
* bottleneck at the peer's NIC RX queue; thus dropping occurs after
* |latency|.
*/
pkt->arrive_time = ossl_time_add(pkt->tx_time,
ossl_ms2time(s->latency));
/*
* It will take longer to detect loss than to detect acknowledgement.
*/
pkt->determination_time = ossl_time_add(pkt->tx_time,
ossl_ms2time(3 * s->latency));
pkt->next_time = pkt->determination_time;
}
pkt->size = sz;
if (!TEST_true(s->ccm->on_data_sent(s->cc, sz)))
goto err;
if (!TEST_true(ossl_pqueue_NET_PKT_push(s->pkts, pkt, &pkt->idx)))
goto err;
return 1;
err:
OPENSSL_free(pkt);
return 0;
}
static int net_sim_process_one(struct net_sim *s, int skip_forward)
{
NET_PKT *pkt = ossl_pqueue_NET_PKT_peek(s->pkts);
if (pkt == NULL)
return 3;
/* Jump forward to the next significant point in time. */
if (skip_forward && ossl_time_compare(pkt->next_time, fake_time) > 0)
fake_time = pkt->next_time;
if (pkt->success && !pkt->arrived
&& ossl_time_compare(fake_time, pkt->arrive_time) >= 0) {
/* Packet arrives */
s->spare_capacity += pkt->size;
pkt->arrived = 1;
ossl_pqueue_NET_PKT_pop(s->pkts);
pkt->next_time = pkt->determination_time;
if (!ossl_pqueue_NET_PKT_push(s->pkts, pkt, &pkt->idx))
return 0;
return 1;
}
if (ossl_time_compare(fake_time, pkt->determination_time) < 0)
return 2;
if (!TEST_true(!pkt->success || pkt->arrived))
return 0;
if (!pkt->success) {
OSSL_CC_LOSS_INFO loss_info = {0};
loss_info.tx_time = pkt->tx_time;
loss_info.tx_size = pkt->size;
if (!TEST_true(s->ccm->on_data_lost(s->cc, &loss_info)))
return 0;
if (!TEST_true(s->ccm->on_data_lost_finished(s->cc, 0)))
return 0;
s->total_lost += pkt->size;
ossl_pqueue_NET_PKT_pop(s->pkts);
OPENSSL_free(pkt);
} else {
OSSL_CC_ACK_INFO ack_info = {0};
ack_info.tx_time = pkt->tx_time;
ack_info.tx_size = pkt->size;
if (!TEST_true(s->ccm->on_data_acked(s->cc, &ack_info)))
return 0;
s->total_acked += pkt->size;
ossl_pqueue_NET_PKT_pop(s->pkts);
OPENSSL_free(pkt);
}
return 1;
}
static int net_sim_process(struct net_sim *s, size_t skip_forward)
{
int rc;
while ((rc = net_sim_process_one(s, skip_forward > 0 ? 1 : 0)) == 1)
if (skip_forward > 0)
--skip_forward;
return rc;
}
/*
* State Dumping Utilities
* =======================
*
* Utilities for outputting CC state information.
*/
#ifdef GENERATE_LOG
static FILE *logfile;
#endif
static int dump_state(const OSSL_CC_METHOD *ccm, OSSL_CC_DATA *cc,
struct net_sim *s)
{
#ifdef GENERATE_LOG
uint64_t cwnd_size, cur_bytes, state;
if (logfile == NULL)
return 1;
if (!TEST_true(ccm->get_option_uint(cc, OSSL_CC_OPTION_CUR_CWND_SIZE,
&cwnd_size)))
return 0;
if (!TEST_true(ccm->get_option_uint(cc, OSSL_CC_OPTION_CUR_BYTES_IN_FLIGHT,
&cur_bytes)))
return 0;
if (!TEST_true(ccm->get_option_uint(cc, OSSL_CC_OPTION_CUR_STATE,
&state)))
return 0;
fprintf(logfile, "%10lu,%10lu,%10lu,%10lu,%10lu,%10lu,%10lu,%10lu,\"%c\"\n",
ossl_time2ms(fake_time),
ccm->get_tx_allowance(cc),
cwnd_size,
cur_bytes,
s->total_acked,
s->total_lost,
s->capacity,
s->spare_capacity,
(char)state);
#endif
return 1;
}
/*
* Simulation Test
* ===============
*
* Simulator-based unit test in which we simulate a network with a certain
* capacity. The average estimated channel capacity should not be too far from
* the actual channel capacity.
*/
static int test_simulate(void)
{
int testresult = 0;
int rc;
int have_sim = 0;
const OSSL_CC_METHOD *ccm = &ossl_cc_newreno_method;
OSSL_CC_DATA *cc = NULL;
size_t mdpl = 1472;
uint64_t total_sent = 0, total_to_send, allowance;
uint64_t actual_capacity = 16000; /* B/s - 128kb/s */
uint64_t cwnd_sample_sum = 0, cwnd_sample_count = 0;
uint64_t diag_cur_bytes_in_flight = UINT64_MAX;
uint64_t diag_cur_cwnd_size = UINT64_MAX;
struct net_sim sim;
OSSL_PARAM params[3], *p = params;
fake_time = TIME_BASE;
if (!TEST_ptr(cc = ccm->new(fake_now, NULL)))
goto err;
if (!TEST_true(net_sim_init(&sim, ccm, cc, actual_capacity, 100)))
goto err;
have_sim = 1;
*p++ = OSSL_PARAM_construct_size_t(OSSL_CC_OPTION_MAX_DGRAM_PAYLOAD_LEN,
&mdpl);
*p++ = OSSL_PARAM_construct_end();
if (!TEST_true(ccm->set_input_params(cc, params)))
goto err;
p = params;
*p++ = OSSL_PARAM_construct_uint64(OSSL_CC_OPTION_CUR_BYTES_IN_FLIGHT,
&diag_cur_bytes_in_flight);
*p++ = OSSL_PARAM_construct_uint64(OSSL_CC_OPTION_CUR_CWND_SIZE,
&diag_cur_cwnd_size);
*p++ = OSSL_PARAM_construct_end();
if (!TEST_true(ccm->bind_diagnostics(cc, params)))
goto err;
ccm->reset(cc);
if (!TEST_uint64_t_ge(allowance = ccm->get_tx_allowance(cc), mdpl))
goto err;
/*
* Start generating traffic. Stop when we've sent 30 MiB.
*/
total_to_send = 30 * 1024 * 1024;
while (total_sent < total_to_send) {
/*
* Assume we are bottlenecked by the network (which is the interesting
* case for testing a congestion controller) and always fill our entire
* TX allowance as and when it becomes available.
*/
for (;;) {
uint64_t sz;
dump_state(ccm, cc, &sim);
allowance = ccm->get_tx_allowance(cc);
sz = allowance > mdpl ? mdpl : allowance;
if (sz > SIZE_MAX)
sz = SIZE_MAX;
/*
* QUIC minimum packet sizes, etc. mean that in practice we will not
* consume the allowance exactly, so only send above a certain size.
*/
if (sz < 30)
break;
step_time(7);
if (!TEST_true(net_sim_send(&sim, (size_t)sz)))
goto err;
total_sent += sz;
}
/* Skip to next event. */
rc = net_sim_process(&sim, 1);
if (!TEST_int_gt(rc, 0))
goto err;
/*
* If we are out of any events to handle at all we definitely should
* have at least one MDPL's worth of allowance as nothing is in flight.
*/
if (rc == 3) {
if (!TEST_uint64_t_eq(diag_cur_bytes_in_flight, 0))
goto err;
if (!TEST_uint64_t_ge(ccm->get_tx_allowance(cc), mdpl))
goto err;
}
/* Update our average of the estimated channel capacity. */
{
uint64_t v = 1;
if (!TEST_uint64_t_ne(diag_cur_bytes_in_flight, UINT64_MAX)
|| !TEST_uint64_t_ne(diag_cur_cwnd_size, UINT64_MAX))
goto err;
cwnd_sample_sum += v;
++cwnd_sample_count;
}
}
/*
* Ensure estimated channel capacity is not too far off from actual channel
* capacity.
*/
{
uint64_t estimated_capacity = cwnd_sample_sum / cwnd_sample_count;
double error = ((double)estimated_capacity / (double)actual_capacity) - 1.0;
TEST_info("est = %6llu kB/s, act=%6llu kB/s (error=%.02f%%)\n",
(unsigned long long)estimated_capacity,
(unsigned long long)actual_capacity,
error * 100.0);
/* Max 5% error */
if (!TEST_double_le(error, 0.05))
goto err;
}
testresult = 1;
err:
if (have_sim)
net_sim_cleanup(&sim);
if (cc != NULL)
ccm->free(cc);
#ifdef GENERATE_LOG
if (logfile != NULL)
fflush(logfile);
#endif
return testresult;
}
/*
* Sanity Test
* ===========
*
* Basic test of the congestion control APIs.
*/
static int test_sanity(void)
{
int testresult = 0;
OSSL_CC_DATA *cc = NULL;
const OSSL_CC_METHOD *ccm = &ossl_cc_newreno_method;
OSSL_CC_LOSS_INFO loss_info = {0};
OSSL_CC_ACK_INFO ack_info = {0};
uint64_t allowance, allowance2;
OSSL_PARAM params[3], *p = params;
size_t mdpl = 1472, diag_mdpl = SIZE_MAX;
uint64_t diag_cur_bytes_in_flight = UINT64_MAX;
fake_time = TIME_BASE;
if (!TEST_ptr(cc = ccm->new(fake_now, NULL)))
goto err;
/* Test configuration of options. */
*p++ = OSSL_PARAM_construct_size_t(OSSL_CC_OPTION_MAX_DGRAM_PAYLOAD_LEN,
&mdpl);
*p++ = OSSL_PARAM_construct_end();
if (!TEST_true(ccm->set_input_params(cc, params)))
goto err;
ccm->reset(cc);
p = params;
*p++ = OSSL_PARAM_construct_size_t(OSSL_CC_OPTION_MAX_DGRAM_PAYLOAD_LEN,
&diag_mdpl);
*p++ = OSSL_PARAM_construct_uint64(OSSL_CC_OPTION_CUR_BYTES_IN_FLIGHT,
&diag_cur_bytes_in_flight);
*p++ = OSSL_PARAM_construct_end();
if (!TEST_true(ccm->bind_diagnostics(cc, params))
|| !TEST_size_t_eq(diag_mdpl, 1472))
goto err;
if (!TEST_uint64_t_ge(allowance = ccm->get_tx_allowance(cc), 1472))
goto err;
/* There is TX allowance so wakeup should be immediate */
if (!TEST_true(ossl_time_is_zero(ccm->get_wakeup_deadline(cc))))
goto err;
/* No bytes should currently be in flight. */
if (!TEST_uint64_t_eq(diag_cur_bytes_in_flight, 0))
goto err;
/* Tell the CC we have sent some data. */
if (!TEST_true(ccm->on_data_sent(cc, 1200)))
goto err;
/* Allowance should have decreased. */
if (!TEST_uint64_t_eq(ccm->get_tx_allowance(cc), allowance - 1200))
goto err;
/* Acknowledge the data. */
ack_info.tx_time = fake_time;
ack_info.tx_size = 1200;
step_time(100);
if (!TEST_true(ccm->on_data_acked(cc, &ack_info)))
goto err;
/* Allowance should have returned. */
if (!TEST_uint64_t_ge(allowance2 = ccm->get_tx_allowance(cc), allowance))
goto err;
/* Test invalidation. */
if (!TEST_true(ccm->on_data_sent(cc, 1200)))
goto err;
/* Allowance should have decreased. */
if (!TEST_uint64_t_eq(ccm->get_tx_allowance(cc), allowance - 1200))
goto err;
if (!TEST_true(ccm->on_data_invalidated(cc, 1200)))
goto err;
/* Allowance should have returned. */
if (!TEST_uint64_t_eq(ccm->get_tx_allowance(cc), allowance2))
goto err;
/* Test loss. */
if (!TEST_uint64_t_ge(allowance = ccm->get_tx_allowance(cc), 1200 + 1300))
goto err;
if (!TEST_true(ccm->on_data_sent(cc, 1200)))
goto err;
if (!TEST_true(ccm->on_data_sent(cc, 1300)))
goto err;
if (!TEST_uint64_t_eq(allowance2 = ccm->get_tx_allowance(cc),
allowance - 1200 - 1300))
goto err;
loss_info.tx_time = fake_time;
loss_info.tx_size = 1200;
step_time(100);
if (!TEST_true(ccm->on_data_lost(cc, &loss_info)))
goto err;
loss_info.tx_size = 1300;
if (!TEST_true(ccm->on_data_lost(cc, &loss_info)))
goto err;
if (!TEST_true(ccm->on_data_lost_finished(cc, 0)))
goto err;
/* Allowance should have changed due to the lost calls */
if (!TEST_uint64_t_ne(ccm->get_tx_allowance(cc), allowance2))
goto err;
/* But it should not be as high as the original value */
if (!TEST_uint64_t_lt(ccm->get_tx_allowance(cc), allowance))
goto err;
testresult = 1;
err:
if (cc != NULL)
ccm->free(cc);
return testresult;
}
int setup_tests(void)
{
#ifdef GENERATE_LOG
logfile = fopen("quic_cc_stats.csv", "w");
fprintf(logfile,
"\"Time\","
"\"TX Allowance\","
"\"CWND Size\","
"\"Bytes in Flight\","
"\"Total Acked\",\"Total Lost\","
"\"Capacity\",\"Spare Capacity\","
"\"State\"\n");
#endif
ADD_TEST(test_simulate);
ADD_TEST(test_sanity);
return 1;
}