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mbedtls/programs/test/udp_proxy.c
Gilles Peskine 1b6c09a62e Switch to the new code style 
Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>
2023-01-11 14:52:35 +01:00

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/*
* UDP proxy: emulate an unreliable UDP connection for DTLS testing
*
* Copyright The Mbed TLS Contributors
* SPDX-License-Identifier: Apache-2.0
*
* 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.
*/
/*
* Warning: this is an internal utility program we use for tests.
* It does break some abstractions from the NET layer, and is thus NOT an
* example of good general usage.
*/
#if !defined(MBEDTLS_CONFIG_FILE)
#include "mbedtls/config.h"
#else
#include MBEDTLS_CONFIG_FILE
#endif
#if defined(MBEDTLS_PLATFORM_C)
#include "mbedtls/platform.h"
#else
#include <stdio.h>
#include <stdlib.h>
#if defined(MBEDTLS_HAVE_TIME)
#include <time.h>
#define mbedtls_time time
#define mbedtls_time_t time_t
#endif
#define mbedtls_printf printf
#define mbedtls_calloc calloc
#define mbedtls_free free
#define mbedtls_exit exit
#define MBEDTLS_EXIT_SUCCESS EXIT_SUCCESS
#define MBEDTLS_EXIT_FAILURE EXIT_FAILURE
#endif /* MBEDTLS_PLATFORM_C */
#if !defined(MBEDTLS_NET_C)
int main(void)
{
mbedtls_printf("MBEDTLS_NET_C not defined.\n");
mbedtls_exit(0);
}
#else
#include "mbedtls/net_sockets.h"
#include "mbedtls/error.h"
#include "mbedtls/ssl.h"
#include "mbedtls/timing.h"
#include <string.h>
/* For select() */
#if (defined(_WIN32) || defined(_WIN32_WCE)) && !defined(EFIX64) && \
!defined(EFI32)
#include <winsock2.h>
#include <windows.h>
#if defined(_MSC_VER)
#if defined(_WIN32_WCE)
#pragma comment( lib, "ws2.lib" )
#else
#pragma comment( lib, "ws2_32.lib" )
#endif
#endif /* _MSC_VER */
#else /* ( _WIN32 || _WIN32_WCE ) && !EFIX64 && !EFI32 */
#if defined(MBEDTLS_HAVE_TIME)
#include <sys/time.h>
#endif
#include <sys/types.h>
#include <unistd.h>
#endif /* ( _WIN32 || _WIN32_WCE ) && !EFIX64 && !EFI32 */
#define MAX_MSG_SIZE 16384 + 2048 /* max record/datagram size */
#define DFL_SERVER_ADDR "localhost"
#define DFL_SERVER_PORT "4433"
#define DFL_LISTEN_ADDR "localhost"
#define DFL_LISTEN_PORT "5556"
#define DFL_PACK 0
#if defined(MBEDTLS_TIMING_C)
#define USAGE_PACK \
" pack=%%d default: 0 (don't pack)\n" \
" options: t > 0 (pack for t milliseconds)\n"
#else
#define USAGE_PACK
#endif
#define USAGE \
"\n usage: udp_proxy param=<>...\n" \
"\n acceptable parameters:\n" \
" server_addr=%%s default: localhost\n" \
" server_port=%%d default: 4433\n" \
" listen_addr=%%s default: localhost\n" \
" listen_port=%%d default: 4433\n" \
"\n" \
" duplicate=%%d default: 0 (no duplication)\n" \
" duplicate about 1:N packets randomly\n" \
" delay=%%d default: 0 (no delayed packets)\n" \
" delay about 1:N packets randomly\n" \
" delay_ccs=0/1 default: 0 (don't delay ChangeCipherSpec)\n" \
" delay_cli=%%s Handshake message from client that should be\n" \
" delayed. Possible values are 'ClientHello',\n" \
" 'Certificate', 'CertificateVerify', and\n" \
" 'ClientKeyExchange'.\n" \
" May be used multiple times, even for the same\n" \
" message, in which case the respective message\n" \
" gets delayed multiple times.\n" \
" delay_srv=%%s Handshake message from server that should be\n" \
" delayed. Possible values are 'HelloRequest',\n" \
" 'ServerHello', 'ServerHelloDone', 'Certificate'\n" \
" 'ServerKeyExchange', 'NewSessionTicket',\n" \
" 'HelloVerifyRequest' and ''CertificateRequest'.\n" \
" May be used multiple times, even for the same\n" \
" message, in which case the respective message\n" \
" gets delayed multiple times.\n" \
" drop=%%d default: 0 (no dropped packets)\n" \
" drop about 1:N packets randomly\n" \
" mtu=%%d default: 0 (unlimited)\n" \
" drop packets larger than N bytes\n" \
" bad_ad=0/1 default: 0 (don't add bad ApplicationData)\n" \
" bad_cid=%%d default: 0 (don't corrupt Connection IDs)\n" \
" duplicate 1:N packets containing a CID,\n" \
" modifying CID in first instance of the packet.\n" \
" protect_hvr=0/1 default: 0 (don't protect HelloVerifyRequest)\n" \
" protect_len=%%d default: (don't protect packets of this size)\n" \
" inject_clihlo=0/1 default: 0 (don't inject fake ClientHello)\n" \
"\n" \
" seed=%%d default: (use current time)\n" \
USAGE_PACK \
"\n"
/*
* global options
*/
#define MAX_DELAYED_HS 10
static struct options {
const char *server_addr; /* address to forward packets to */
const char *server_port; /* port to forward packets to */
const char *listen_addr; /* address for accepting client connections */
const char *listen_port; /* port for accepting client connections */
int duplicate; /* duplicate 1 in N packets (none if 0) */
int delay; /* delay 1 packet in N (none if 0) */
int delay_ccs; /* delay ChangeCipherSpec */
char *delay_cli[MAX_DELAYED_HS]; /* handshake types of messages from
* client that should be delayed. */
uint8_t delay_cli_cnt; /* Number of entries in delay_cli. */
char *delay_srv[MAX_DELAYED_HS]; /* handshake types of messages from
* server that should be delayed. */
uint8_t delay_srv_cnt; /* Number of entries in delay_srv. */
int drop; /* drop 1 packet in N (none if 0) */
int mtu; /* drop packets larger than this */
int bad_ad; /* inject corrupted ApplicationData record */
unsigned bad_cid; /* inject corrupted CID record */
int protect_hvr; /* never drop or delay HelloVerifyRequest */
int protect_len; /* never drop/delay packet of the given size*/
int inject_clihlo; /* inject fake ClientHello after handshake */
unsigned pack; /* merge packets into single datagram for
* at most \c merge milliseconds if > 0 */
unsigned int seed; /* seed for "random" events */
} opt;
static void exit_usage(const char *name, const char *value)
{
if (value == NULL) {
mbedtls_printf(" unknown option or missing value: %s\n", name);
} else {
mbedtls_printf(" option %s: illegal value: %s\n", name, value);
}
mbedtls_printf(USAGE);
mbedtls_exit(1);
}
static void get_options(int argc, char *argv[])
{
int i;
char *p, *q;
opt.server_addr = DFL_SERVER_ADDR;
opt.server_port = DFL_SERVER_PORT;
opt.listen_addr = DFL_LISTEN_ADDR;
opt.listen_port = DFL_LISTEN_PORT;
opt.pack = DFL_PACK;
/* Other members default to 0 */
opt.delay_cli_cnt = 0;
opt.delay_srv_cnt = 0;
memset(opt.delay_cli, 0, sizeof(opt.delay_cli));
memset(opt.delay_srv, 0, sizeof(opt.delay_srv));
for (i = 1; i < argc; i++) {
p = argv[i];
if ((q = strchr(p, '=')) == NULL) {
exit_usage(p, NULL);
}
*q++ = '\0';
if (strcmp(p, "server_addr") == 0) {
opt.server_addr = q;
} else if (strcmp(p, "server_port") == 0) {
opt.server_port = q;
} else if (strcmp(p, "listen_addr") == 0) {
opt.listen_addr = q;
} else if (strcmp(p, "listen_port") == 0) {
opt.listen_port = q;
} else if (strcmp(p, "duplicate") == 0) {
opt.duplicate = atoi(q);
if (opt.duplicate < 0 || opt.duplicate > 20) {
exit_usage(p, q);
}
} else if (strcmp(p, "delay") == 0) {
opt.delay = atoi(q);
if (opt.delay < 0 || opt.delay > 20 || opt.delay == 1) {
exit_usage(p, q);
}
} else if (strcmp(p, "delay_ccs") == 0) {
opt.delay_ccs = atoi(q);
if (opt.delay_ccs < 0 || opt.delay_ccs > 1) {
exit_usage(p, q);
}
} else if (strcmp(p, "delay_cli") == 0 ||
strcmp(p, "delay_srv") == 0) {
uint8_t *delay_cnt;
char **delay_list;
size_t len;
char *buf;
if (strcmp(p, "delay_cli") == 0) {
delay_cnt = &opt.delay_cli_cnt;
delay_list = opt.delay_cli;
} else {
delay_cnt = &opt.delay_srv_cnt;
delay_list = opt.delay_srv;
}
if (*delay_cnt == MAX_DELAYED_HS) {
mbedtls_printf(" too many uses of %s: only %d allowed\n",
p, MAX_DELAYED_HS);
exit_usage(p, NULL);
}
len = strlen(q);
buf = mbedtls_calloc(1, len + 1);
if (buf == NULL) {
mbedtls_printf(" Allocation failure\n");
exit(1);
}
memcpy(buf, q, len + 1);
delay_list[(*delay_cnt)++] = buf;
} else if (strcmp(p, "drop") == 0) {
opt.drop = atoi(q);
if (opt.drop < 0 || opt.drop > 20 || opt.drop == 1) {
exit_usage(p, q);
}
} else if (strcmp(p, "pack") == 0) {
#if defined(MBEDTLS_TIMING_C)
opt.pack = (unsigned) atoi(q);
#else
mbedtls_printf(" option pack only defined if MBEDTLS_TIMING_C is enabled\n");
exit(1);
#endif
} else if (strcmp(p, "mtu") == 0) {
opt.mtu = atoi(q);
if (opt.mtu < 0 || opt.mtu > MAX_MSG_SIZE) {
exit_usage(p, q);
}
} else if (strcmp(p, "bad_ad") == 0) {
opt.bad_ad = atoi(q);
if (opt.bad_ad < 0 || opt.bad_ad > 1) {
exit_usage(p, q);
}
}
#if defined(MBEDTLS_SSL_DTLS_CONNECTION_ID)
else if (strcmp(p, "bad_cid") == 0) {
opt.bad_cid = (unsigned) atoi(q);
}
#endif /* MBEDTLS_SSL_DTLS_CONNECTION_ID */
else if (strcmp(p, "protect_hvr") == 0) {
opt.protect_hvr = atoi(q);
if (opt.protect_hvr < 0 || opt.protect_hvr > 1) {
exit_usage(p, q);
}
} else if (strcmp(p, "protect_len") == 0) {
opt.protect_len = atoi(q);
if (opt.protect_len < 0) {
exit_usage(p, q);
}
} else if (strcmp(p, "inject_clihlo") == 0) {
opt.inject_clihlo = atoi(q);
if (opt.inject_clihlo < 0 || opt.inject_clihlo > 1) {
exit_usage(p, q);
}
} else if (strcmp(p, "seed") == 0) {
opt.seed = atoi(q);
if (opt.seed == 0) {
exit_usage(p, q);
}
} else {
exit_usage(p, NULL);
}
}
}
static const char *msg_type(unsigned char *msg, size_t len)
{
if (len < 1) {
return "Invalid";
}
switch (msg[0]) {
case MBEDTLS_SSL_MSG_CHANGE_CIPHER_SPEC: return "ChangeCipherSpec";
case MBEDTLS_SSL_MSG_ALERT: return "Alert";
case MBEDTLS_SSL_MSG_APPLICATION_DATA: return "ApplicationData";
case MBEDTLS_SSL_MSG_CID: return "CID";
case MBEDTLS_SSL_MSG_HANDSHAKE: break; /* See below */
default: return "Unknown";
}
if (len < 13 + 12) {
return "Invalid handshake";
}
/*
* Our handshake message are less than 2^16 bytes long, so they should
* have 0 as the first byte of length, frag_offset and frag_length.
* Otherwise, assume they are encrypted.
*/
if (msg[14] || msg[19] || msg[22]) {
return "Encrypted handshake";
}
switch (msg[13]) {
case MBEDTLS_SSL_HS_HELLO_REQUEST: return "HelloRequest";
case MBEDTLS_SSL_HS_CLIENT_HELLO: return "ClientHello";
case MBEDTLS_SSL_HS_SERVER_HELLO: return "ServerHello";
case MBEDTLS_SSL_HS_HELLO_VERIFY_REQUEST: return "HelloVerifyRequest";
case MBEDTLS_SSL_HS_NEW_SESSION_TICKET: return "NewSessionTicket";
case MBEDTLS_SSL_HS_CERTIFICATE: return "Certificate";
case MBEDTLS_SSL_HS_SERVER_KEY_EXCHANGE: return "ServerKeyExchange";
case MBEDTLS_SSL_HS_CERTIFICATE_REQUEST: return "CertificateRequest";
case MBEDTLS_SSL_HS_SERVER_HELLO_DONE: return "ServerHelloDone";
case MBEDTLS_SSL_HS_CERTIFICATE_VERIFY: return "CertificateVerify";
case MBEDTLS_SSL_HS_CLIENT_KEY_EXCHANGE: return "ClientKeyExchange";
case MBEDTLS_SSL_HS_FINISHED: return "Finished";
default: return "Unknown handshake";
}
}
#if defined(MBEDTLS_TIMING_C)
/* Return elapsed time in milliseconds since the first call */
static unsigned elapsed_time(void)
{
static int initialized = 0;
static struct mbedtls_timing_hr_time hires;
if (initialized == 0) {
(void) mbedtls_timing_get_timer(&hires, 1);
initialized = 1;
return 0;
}
return mbedtls_timing_get_timer(&hires, 0);
}
typedef struct {
mbedtls_net_context *ctx;
const char *description;
unsigned packet_lifetime;
unsigned num_datagrams;
unsigned char data[MAX_MSG_SIZE];
size_t len;
} ctx_buffer;
static ctx_buffer outbuf[2];
static int ctx_buffer_flush(ctx_buffer *buf)
{
int ret;
mbedtls_printf(" %05u flush %s: %u bytes, %u datagrams, last %u ms\n",
elapsed_time(), buf->description,
(unsigned) buf->len, buf->num_datagrams,
elapsed_time() - buf->packet_lifetime);
ret = mbedtls_net_send(buf->ctx, buf->data, buf->len);
buf->len = 0;
buf->num_datagrams = 0;
return ret;
}
static unsigned ctx_buffer_time_remaining(ctx_buffer *buf)
{
unsigned const cur_time = elapsed_time();
if (buf->num_datagrams == 0) {
return (unsigned) -1;
}
if (cur_time - buf->packet_lifetime >= opt.pack) {
return 0;
}
return opt.pack - (cur_time - buf->packet_lifetime);
}
static int ctx_buffer_append(ctx_buffer *buf,
const unsigned char *data,
size_t len)
{
int ret;
if (len > (size_t) INT_MAX) {
return -1;
}
if (len > sizeof(buf->data)) {
mbedtls_printf(" ! buffer size %u too large (max %u)\n",
(unsigned) len, (unsigned) sizeof(buf->data));
return -1;
}
if (sizeof(buf->data) - buf->len < len) {
if ((ret = ctx_buffer_flush(buf)) <= 0) {
mbedtls_printf("ctx_buffer_flush failed with -%#04x", (unsigned int) -ret);
return ret;
}
}
memcpy(buf->data + buf->len, data, len);
buf->len += len;
if (++buf->num_datagrams == 1) {
buf->packet_lifetime = elapsed_time();
}
return (int) len;
}
#endif /* MBEDTLS_TIMING_C */
static int dispatch_data(mbedtls_net_context *ctx,
const unsigned char *data,
size_t len)
{
int ret;
#if defined(MBEDTLS_TIMING_C)
ctx_buffer *buf = NULL;
if (opt.pack > 0) {
if (outbuf[0].ctx == ctx) {
buf = &outbuf[0];
} else if (outbuf[1].ctx == ctx) {
buf = &outbuf[1];
}
if (buf == NULL) {
return -1;
}
return ctx_buffer_append(buf, data, len);
}
#endif /* MBEDTLS_TIMING_C */
ret = mbedtls_net_send(ctx, data, len);
if (ret < 0) {
mbedtls_printf("net_send returned -%#04x\n", (unsigned int) -ret);
}
return ret;
}
typedef struct {
mbedtls_net_context *dst;
const char *way;
const char *type;
unsigned len;
unsigned char buf[MAX_MSG_SIZE];
} packet;
/* Print packet. Outgoing packets come with a reason (forward, dupl, etc.) */
void print_packet(const packet *p, const char *why)
{
#if defined(MBEDTLS_TIMING_C)
if (why == NULL) {
mbedtls_printf(" %05u dispatch %s %s (%u bytes)\n",
elapsed_time(), p->way, p->type, p->len);
} else {
mbedtls_printf(" %05u dispatch %s %s (%u bytes): %s\n",
elapsed_time(), p->way, p->type, p->len, why);
}
#else
if (why == NULL) {
mbedtls_printf(" dispatch %s %s (%u bytes)\n",
p->way, p->type, p->len);
} else {
mbedtls_printf(" dispatch %s %s (%u bytes): %s\n",
p->way, p->type, p->len, why);
}
#endif
fflush(stdout);
}
/*
* In order to test the server's behaviour when receiving a ClientHello after
* the connection is established (this could be a hard reset from the client,
* but the server must not drop the existing connection before establishing
* client reachability, see RFC 6347 Section 4.2.8), we memorize the first
* ClientHello we see (which can't have a cookie), then replay it after the
* first ApplicationData record - then we're done.
*
* This is controlled by the inject_clihlo option.
*
* We want an explicit state and a place to store the packet.
*/
typedef enum {
ICH_INIT, /* haven't seen the first ClientHello yet */
ICH_CACHED, /* cached the initial ClientHello */
ICH_INJECTED, /* ClientHello already injected, done */
} inject_clihlo_state_t;
static inject_clihlo_state_t inject_clihlo_state;
static packet initial_clihlo;
int send_packet(const packet *p, const char *why)
{
int ret;
mbedtls_net_context *dst = p->dst;
/* save initial ClientHello? */
if (opt.inject_clihlo != 0 &&
inject_clihlo_state == ICH_INIT &&
strcmp(p->type, "ClientHello") == 0) {
memcpy(&initial_clihlo, p, sizeof(packet));
inject_clihlo_state = ICH_CACHED;
}
/* insert corrupted CID record? */
if (opt.bad_cid != 0 &&
strcmp(p->type, "CID") == 0 &&
(rand() % opt.bad_cid) == 0) {
unsigned char buf[MAX_MSG_SIZE];
memcpy(buf, p->buf, p->len);
/* The CID resides at offset 11 in the DTLS record header. */
buf[11] ^= 1;
print_packet(p, "modified CID");
if ((ret = dispatch_data(dst, buf, p->len)) <= 0) {
mbedtls_printf(" ! dispatch returned %d\n", ret);
return ret;
}
}
/* insert corrupted ApplicationData record? */
if (opt.bad_ad &&
strcmp(p->type, "ApplicationData") == 0) {
unsigned char buf[MAX_MSG_SIZE];
memcpy(buf, p->buf, p->len);
if (p->len <= 13) {
mbedtls_printf(" ! can't corrupt empty AD record");
} else {
++buf[13];
print_packet(p, "corrupted");
}
if ((ret = dispatch_data(dst, buf, p->len)) <= 0) {
mbedtls_printf(" ! dispatch returned %d\n", ret);
return ret;
}
}
print_packet(p, why);
if ((ret = dispatch_data(dst, p->buf, p->len)) <= 0) {
mbedtls_printf(" ! dispatch returned %d\n", ret);
return ret;
}
/* Don't duplicate Application Data, only handshake covered */
if (opt.duplicate != 0 &&
strcmp(p->type, "ApplicationData") != 0 &&
rand() % opt.duplicate == 0) {
print_packet(p, "duplicated");
if ((ret = dispatch_data(dst, p->buf, p->len)) <= 0) {
mbedtls_printf(" ! dispatch returned %d\n", ret);
return ret;
}
}
/* Inject ClientHello after first ApplicationData */
if (opt.inject_clihlo != 0 &&
inject_clihlo_state == ICH_CACHED &&
strcmp(p->type, "ApplicationData") == 0) {
print_packet(&initial_clihlo, "injected");
if ((ret = dispatch_data(dst, initial_clihlo.buf,
initial_clihlo.len)) <= 0) {
mbedtls_printf(" ! dispatch returned %d\n", ret);
return ret;
}
inject_clihlo_state = ICH_INJECTED;
}
return 0;
}
#define MAX_DELAYED_MSG 5
static size_t prev_len;
static packet prev[MAX_DELAYED_MSG];
void clear_pending(void)
{
memset(&prev, 0, sizeof(prev));
prev_len = 0;
}
void delay_packet(packet *delay)
{
if (prev_len == MAX_DELAYED_MSG) {
return;
}
memcpy(&prev[prev_len++], delay, sizeof(packet));
}
int send_delayed()
{
uint8_t offset;
int ret;
for (offset = 0; offset < prev_len; offset++) {
ret = send_packet(&prev[offset], "delayed");
if (ret != 0) {
return ret;
}
}
clear_pending();
return 0;
}
/*
* Avoid dropping or delaying a packet that was already dropped or delayed
* ("held") twice: this only results in uninteresting timeouts. We can't rely
* on type to identify packets, since during renegotiation they're all
* encrypted. So, rely on size mod 2048 (which is usually just size).
*
* We only hold packets at the level of entire datagrams, not at the level
* of records. In particular, if the peer changes the way it packs multiple
* records into a single datagram, we don't necessarily count the number of
* times a record has been held correctly. However, the only known reason
* why a peer would change datagram packing is disabling the latter on
* retransmission, in which case we'd hold involved records at most
* HOLD_MAX + 1 times.
*/
static unsigned char held[2048] = { 0 };
#define HOLD_MAX 2
int handle_message(const char *way,
mbedtls_net_context *dst,
mbedtls_net_context *src)
{
int ret;
packet cur;
size_t id;
uint8_t delay_idx;
char **delay_list;
uint8_t delay_list_len;
/* receive packet */
if ((ret = mbedtls_net_recv(src, cur.buf, sizeof(cur.buf))) <= 0) {
mbedtls_printf(" ! mbedtls_net_recv returned %d\n", ret);
return ret;
}
cur.len = ret;
cur.type = msg_type(cur.buf, cur.len);
cur.way = way;
cur.dst = dst;
print_packet(&cur, NULL);
id = cur.len % sizeof(held);
if (strcmp(way, "S <- C") == 0) {
delay_list = opt.delay_cli;
delay_list_len = opt.delay_cli_cnt;
} else {
delay_list = opt.delay_srv;
delay_list_len = opt.delay_srv_cnt;
}
/* Check if message type is in the list of messages
* that should be delayed */
for (delay_idx = 0; delay_idx < delay_list_len; delay_idx++) {
if (delay_list[delay_idx] == NULL) {
continue;
}
if (strcmp(delay_list[delay_idx], cur.type) == 0) {
/* Delay message */
delay_packet(&cur);
/* Remove entry from list */
mbedtls_free(delay_list[delay_idx]);
delay_list[delay_idx] = NULL;
return 0;
}
}
/* do we want to drop, delay, or forward it? */
if ((opt.mtu != 0 &&
cur.len > (unsigned) opt.mtu) ||
(opt.drop != 0 &&
strcmp(cur.type, "CID") != 0 &&
strcmp(cur.type, "ApplicationData") != 0 &&
!(opt.protect_hvr &&
strcmp(cur.type, "HelloVerifyRequest") == 0) &&
cur.len != (size_t) opt.protect_len &&
held[id] < HOLD_MAX &&
rand() % opt.drop == 0)) {
++held[id];
} else if ((opt.delay_ccs == 1 &&
strcmp(cur.type, "ChangeCipherSpec") == 0) ||
(opt.delay != 0 &&
strcmp(cur.type, "CID") != 0 &&
strcmp(cur.type, "ApplicationData") != 0 &&
!(opt.protect_hvr &&
strcmp(cur.type, "HelloVerifyRequest") == 0) &&
cur.len != (size_t) opt.protect_len &&
held[id] < HOLD_MAX &&
rand() % opt.delay == 0)) {
++held[id];
delay_packet(&cur);
} else {
/* forward and possibly duplicate */
if ((ret = send_packet(&cur, "forwarded")) != 0) {
return ret;
}
/* send previously delayed messages if any */
ret = send_delayed();
if (ret != 0) {
return ret;
}
}
return 0;
}
int main(int argc, char *argv[])
{
int ret = 1;
int exit_code = MBEDTLS_EXIT_FAILURE;
uint8_t delay_idx;
mbedtls_net_context listen_fd, client_fd, server_fd;
#if defined(MBEDTLS_TIMING_C)
struct timeval tm;
#endif
struct timeval *tm_ptr = NULL;
int nb_fds;
fd_set read_fds;
mbedtls_net_init(&listen_fd);
mbedtls_net_init(&client_fd);
mbedtls_net_init(&server_fd);
get_options(argc, argv);
/*
* Decisions to drop/delay/duplicate packets are pseudo-random: dropping
* exactly 1 in N packets would lead to problems when a flight has exactly
* N packets: the same packet would be dropped on every resend.
*
* In order to be able to reproduce problems reliably, the seed may be
* specified explicitly.
*/
if (opt.seed == 0) {
#if defined(MBEDTLS_HAVE_TIME)
opt.seed = (unsigned int) mbedtls_time(NULL);
#else
opt.seed = 1;
#endif /* MBEDTLS_HAVE_TIME */
mbedtls_printf(" . Pseudo-random seed: %u\n", opt.seed);
}
srand(opt.seed);
/*
* 0. "Connect" to the server
*/
mbedtls_printf(" . Connect to server on UDP/%s/%s ...",
opt.server_addr, opt.server_port);
fflush(stdout);
if ((ret = mbedtls_net_connect(&server_fd, opt.server_addr, opt.server_port,
MBEDTLS_NET_PROTO_UDP)) != 0) {
mbedtls_printf(" failed\n ! mbedtls_net_connect returned %d\n\n", ret);
goto exit;
}
mbedtls_printf(" ok\n");
/*
* 1. Setup the "listening" UDP socket
*/
mbedtls_printf(" . Bind on UDP/%s/%s ...",
opt.listen_addr, opt.listen_port);
fflush(stdout);
if ((ret = mbedtls_net_bind(&listen_fd, opt.listen_addr, opt.listen_port,
MBEDTLS_NET_PROTO_UDP)) != 0) {
mbedtls_printf(" failed\n ! mbedtls_net_bind returned %d\n\n", ret);
goto exit;
}
mbedtls_printf(" ok\n");
/*
* 2. Wait until a client connects
*/
accept:
mbedtls_net_free(&client_fd);
mbedtls_printf(" . Waiting for a remote connection ...");
fflush(stdout);
if ((ret = mbedtls_net_accept(&listen_fd, &client_fd,
NULL, 0, NULL)) != 0) {
mbedtls_printf(" failed\n ! mbedtls_net_accept returned %d\n\n", ret);
goto exit;
}
mbedtls_printf(" ok\n");
/*
* 3. Forward packets forever (kill the process to terminate it)
*/
clear_pending();
memset(held, 0, sizeof(held));
nb_fds = client_fd.fd;
if (nb_fds < server_fd.fd) {
nb_fds = server_fd.fd;
}
if (nb_fds < listen_fd.fd) {
nb_fds = listen_fd.fd;
}
++nb_fds;
#if defined(MBEDTLS_TIMING_C)
if (opt.pack > 0) {
outbuf[0].ctx = &server_fd;
outbuf[0].description = "S <- C";
outbuf[0].num_datagrams = 0;
outbuf[0].len = 0;
outbuf[1].ctx = &client_fd;
outbuf[1].description = "S -> C";
outbuf[1].num_datagrams = 0;
outbuf[1].len = 0;
}
#endif /* MBEDTLS_TIMING_C */
while (1) {
#if defined(MBEDTLS_TIMING_C)
if (opt.pack > 0) {
unsigned max_wait_server, max_wait_client, max_wait;
max_wait_server = ctx_buffer_time_remaining(&outbuf[0]);
max_wait_client = ctx_buffer_time_remaining(&outbuf[1]);
max_wait = (unsigned) -1;
if (max_wait_server == 0) {
ctx_buffer_flush(&outbuf[0]);
} else {
max_wait = max_wait_server;
}
if (max_wait_client == 0) {
ctx_buffer_flush(&outbuf[1]);
} else {
if (max_wait_client < max_wait) {
max_wait = max_wait_client;
}
}
if (max_wait != (unsigned) -1) {
tm.tv_sec = max_wait / 1000;
tm.tv_usec = (max_wait % 1000) * 1000;
tm_ptr = &tm;
} else {
tm_ptr = NULL;
}
}
#endif /* MBEDTLS_TIMING_C */
FD_ZERO(&read_fds);
FD_SET(server_fd.fd, &read_fds);
FD_SET(client_fd.fd, &read_fds);
FD_SET(listen_fd.fd, &read_fds);
if ((ret = select(nb_fds, &read_fds, NULL, NULL, tm_ptr)) < 0) {
perror("select");
goto exit;
}
if (FD_ISSET(listen_fd.fd, &read_fds)) {
goto accept;
}
if (FD_ISSET(client_fd.fd, &read_fds)) {
if ((ret = handle_message("S <- C",
&server_fd, &client_fd)) != 0) {
goto accept;
}
}
if (FD_ISSET(server_fd.fd, &read_fds)) {
if ((ret = handle_message("S -> C",
&client_fd, &server_fd)) != 0) {
goto accept;
}
}
}
exit_code = MBEDTLS_EXIT_SUCCESS;
exit:
#ifdef MBEDTLS_ERROR_C
if (exit_code != MBEDTLS_EXIT_SUCCESS) {
char error_buf[100];
mbedtls_strerror(ret, error_buf, 100);
mbedtls_printf("Last error was: -0x%04X - %s\n\n", (unsigned int) -ret, error_buf);
fflush(stdout);
}
#endif
for (delay_idx = 0; delay_idx < MAX_DELAYED_HS; delay_idx++) {
mbedtls_free(opt.delay_cli[delay_idx]);
mbedtls_free(opt.delay_srv[delay_idx]);
}
mbedtls_net_free(&client_fd);
mbedtls_net_free(&server_fd);
mbedtls_net_free(&listen_fd);
#if defined(_WIN32)
mbedtls_printf(" Press Enter to exit this program.\n");
fflush(stdout); getchar();
#endif
mbedtls_exit(exit_code);
}
#endif /* MBEDTLS_NET_C */
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