Make decisions pseudo-random in udp_proxy
diff --git a/programs/test/udp_proxy.c b/programs/test/udp_proxy.c
index 191bb96..7b788d7 100644
--- a/programs/test/udp_proxy.c
+++ b/programs/test/udp_proxy.c
@@ -44,9 +44,7 @@
#include <stdio.h>
#include <stdlib.h>
-#if defined(POLARSSL_HAVE_TIME)
#include <time.h>
-#endif
/* For select() */
#if (defined(_WIN32) || defined(_WIN32_WCE)) && !defined(EFIX64) && \
@@ -87,15 +85,17 @@
" listen_port=%%d default: 4433\n" \
"\n" \
" duplicate=%%d default: 0 (no duplication)\n" \
- " duplicate 1 packet every N packets\n" \
+ " duplicate about 1:N packets randomly\n" \
" delay=%%d default: 0 (no delayed packets)\n" \
- " delay 1 packet every N packets\n" \
+ " delay about 1:N packets randomly\n" \
" delay_ccs=%%d default: 0 (don't delay ChangeCipherSuite)\n" \
" drop=%%d default: 0 (no dropped packets)\n" \
- " drop 1 packet every N packets\n" \
+ " drop about 1:N packets randomly\n" \
" mtu=%%d default: 0 (unlimited)\n" \
" drop packets larger than N bytes\n" \
" bad_ad=%%d default: 0 (don't add bad ApplicationData)\n" \
+ "\n" \
+ " seed=%%d default: (use current time)\n" \
"\n"
/*
@@ -114,30 +114,10 @@
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 int seed; /* seed for "random" events */
} opt;
-/*
- * global counters
- */
-static int dupl_cnt;
-static int delay_cnt;
-static int drop_cnt;
-
-/* Do not always start with the same state */
-static void randomize_counters( void )
-{
-#if defined(POLARSSL_HAVE_TIME)
- srand( time( NULL ) );
-#endif
-
- if( opt.duplicate != 0 )
- dupl_cnt = rand() % opt.duplicate;
- if( opt.delay != 0 )
- delay_cnt = rand() % opt.delay;
- if( opt.drop != 0 )
- drop_cnt = rand() % opt.drop;
-}
-
static void exit_usage( const char *name, const char *value )
{
if( value == NULL )
@@ -186,13 +166,13 @@
else if( strcmp( p, "duplicate" ) == 0 )
{
opt.duplicate = atoi( q );
- if( opt.duplicate < 0 || opt.duplicate > 10 )
+ 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 > 10 || opt.delay == 1 )
+ if( opt.delay < 0 || opt.delay > 20 || opt.delay == 1 )
exit_usage( p, q );
}
else if( strcmp( p, "delay_ccs" ) == 0 )
@@ -204,7 +184,7 @@
else if( strcmp( p, "drop" ) == 0 )
{
opt.drop = atoi( q );
- if( opt.drop < 0 || opt.drop > 10 || opt.drop == 1 )
+ if( opt.drop < 0 || opt.drop > 20 || opt.drop == 1 )
exit_usage( p, q );
}
else if( strcmp( p, "mtu" ) == 0 )
@@ -219,6 +199,12 @@
if( opt.bad_ad < 0 || opt.bad_ad > 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 );
}
@@ -327,9 +313,8 @@
/* Don't duplicate Application Data, only handshake covered */
if( opt.duplicate != 0 &&
strcmp( p->type, "ApplicationData" ) != 0 &&
- ++dupl_cnt == opt.duplicate )
+ rand() % opt.duplicate == 0 )
{
- dupl_cnt = 0;
print_packet( p, "duplicated" );
if( ( ret = net_send( p->dst, p->buf, p->len ) ) <= 0 )
@@ -369,9 +354,9 @@
strcmp( cur.type, "NewSessionTicket" ) != 0 && // temporary
strcmp( cur.type, "ChangeCipherSpec" ) != 0 && // temporary
strcmp( cur.type, "Unknown handshake" ) != 0 && // temporary
- ++drop_cnt == opt.drop ) )
+ rand() % opt.drop == 0 ) )
{
- drop_cnt = 0;
+ ; /* Nothing to do */
}
else if( ( opt.delay_ccs == 1 &&
strcmp( cur.type, "ChangeCipherSpec" ) == 0 ) ||
@@ -380,9 +365,8 @@
strcmp( cur.type, "NewSessionTicket" ) != 0 && // temporary
strcmp( cur.type, "ChangeCipherSpec" ) != 0 && // temporary
strcmp( cur.type, "Unknown handshake" ) != 0 && // temporary
- ++delay_cnt == opt.delay ) )
+ rand() % opt.delay == 0 ) )
{
- delay_cnt = 0;
memcpy( &prev, &cur, sizeof( packet ) );
}
else
@@ -416,7 +400,22 @@
fd_set read_fds;
get_options( argc, argv );
- randomize_counters();
+
+ /*
+ * 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 )
+ {
+ opt.seed = time( NULL );
+ printf( " . Pseudo-random seed: %u\n", opt.seed );
+ }
+
+ srand( opt.seed );
/*
* 0. "Connect" to the server