blob: 41a90a9ada28525ab391f0419832815b5113962f [file] [log] [blame]
/*
* UDP proxy: emulate an unreliable UDP connexion 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.
*/
#define MBEDTLS_ALLOW_PRIVATE_ACCESS
#include "mbedtls/build_info.h"
#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 ellapsed_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",
ellapsed_time(), buf->description,
(unsigned) buf->len, buf->num_datagrams,
ellapsed_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 = ellapsed_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 = ellapsed_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",
ellapsed_time(), p->way, p->type, p->len );
else
mbedtls_printf( " %05u dispatch %s %s (%u bytes): %s\n",
ellapsed_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 */