UDP proxy: Allow more than one message to be delayed

Previously, the UDP proxy could only remember one delayed message
for future transmission; if two messages were delayed in succession,
without another one being normally forwarded in between,
the message that got delayed first would be dropped.

This commit enhances the UDP proxy to allow to delay an arbitrary
(compile-time fixed) number of messages in succession.
This commit is contained in:
Hanno Becker 2018-08-21 16:39:51 +01:00
parent 55e9e2aa6b
commit 101bcba26f

View File

@ -556,11 +556,37 @@ int send_packet( const packet *p, const char *why )
return( 0 ); return( 0 );
} }
static packet prev; #define MAX_DELAYED_MSG 5
static size_t prev_len;
static packet prev[MAX_DELAYED_MSG];
void clear_pending( void ) void clear_pending( void )
{ {
memset( &prev, 0, sizeof( packet ) ); memset( &prev, 0, sizeof( packet ) );
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 );
} }
/* /*
@ -647,7 +673,7 @@ int handle_message( const char *way,
if( strcmp( delay_list[ delay_idx ], cur.type ) == 0 ) if( strcmp( delay_list[ delay_idx ], cur.type ) == 0 )
{ {
/* Delay message */ /* Delay message */
memcpy( &prev, &cur, sizeof( packet ) ); delay_packet( &cur );
/* Remove entry from list */ /* Remove entry from list */
mbedtls_free( delay_list[delay_idx] ); mbedtls_free( delay_list[delay_idx] );
@ -676,12 +702,11 @@ int handle_message( const char *way,
strcmp( cur.type, "ApplicationData" ) != 0 && strcmp( cur.type, "ApplicationData" ) != 0 &&
! ( opt.protect_hvr && ! ( opt.protect_hvr &&
strcmp( cur.type, "HelloVerifyRequest" ) == 0 ) && strcmp( cur.type, "HelloVerifyRequest" ) == 0 ) &&
prev.dst == NULL &&
cur.len != (size_t) opt.protect_len && cur.len != (size_t) opt.protect_len &&
dropped[id] < DROP_MAX && dropped[id] < DROP_MAX &&
rand() % opt.delay == 0 ) ) rand() % opt.delay == 0 ) )
{ {
memcpy( &prev, &cur, sizeof( packet ) ); delay_packet( &cur );
} }
else else
{ {
@ -689,15 +714,11 @@ int handle_message( const char *way,
if( ( ret = send_packet( &cur, "forwarded" ) ) != 0 ) if( ( ret = send_packet( &cur, "forwarded" ) ) != 0 )
return( ret ); return( ret );
/* send previously delayed message if any */ /* send previously delayed messages if any */
if( prev.dst != NULL ) ret = send_delayed();
{
ret = send_packet( &prev, "delayed" );
memset( &prev, 0, sizeof( packet ) );
if( ret != 0 ) if( ret != 0 )
return( ret ); return( ret );
} }
}
return( 0 ); return( 0 );
} }