@ -80,6 +80,8 @@ ASTERISK_FILE_VERSION(__FILE__, "$Revision$")
# define ZFONE_PROFILE_ID 0x505a
# define DEFAULT_LEARNING_MIN_SEQUENTIAL 4
extern struct ast_srtp_res * res_srtp ;
static int dtmftimeout = DEFAULT_DTMF_TIMEOUT ;
@ -96,7 +98,8 @@ static int rtcpdebugport; /*< Debug only RTCP packets from IP or IP+Port if por
# ifdef SO_NO_CHECK
static int nochecksums ;
# endif
static int strictrtp ;
static int strictrtp ; /*< Only accept RTP frames from a defined source. If we receive an indication of a changing source, enter learning mode. */
static int learning_min_sequential ; /*< Number of sequential RTP frames needed from a single source during learning mode to accept new source. */
enum strict_rtp_state {
STRICT_RTP_OPEN = 0 , /*! No RTP packets should be dropped, all sources accepted */
@ -176,6 +179,13 @@ struct ast_rtp {
struct ast_sockaddr strict_rtp_address ; /*!< Remote address information for strict RTP purposes */
struct ast_sockaddr alt_rtp_address ; /*!<Alternate remote address information */
/*
* Learning mode values based on pjmedia ' s probation mode . Many of these values are redundant to the above ,
* but these are in place to keep learning mode sequence values sealed from their normal counterparts .
*/
uint16_t learning_max_seq ; /*!< Highest sequence number heard */
int learning_probation ; /*!< Sequential packets untill source is valid */
struct rtp_red * red ;
} ;
@ -460,6 +470,52 @@ static int create_new_socket(const char *type, int af)
return sock ;
}
/*!
* \ internal
* \ brief Initializes sequence values and probation for learning mode .
* \ note This is an adaptation of pjmedia ' s pjmedia_rtp_seq_init function .
*
* \ param rtp pointer to rtp struct used with the received rtp packet .
* \ param seq sequence number read from the rtp header
*/
static void rtp_learning_seq_init ( struct ast_rtp * rtp , uint16_t seq )
{
rtp - > learning_max_seq = seq - 1 ;
rtp - > learning_probation = learning_min_sequential ;
}
/*!
* \ internal
* \ brief Updates sequence information for learning mode and determines if probation / learning mode should remain in effect .
* \ note This function was adapted from pjmedia ' s pjmedia_rtp_seq_update function .
*
* \ param rtp pointer to rtp struct used with the received rtp packet .
* \ param seq sequence number read from the rtp header
* \ return boolean value indicating if probation mode is active at the end of the function
*/
static int rtp_learning_rtp_seq_update ( struct ast_rtp * rtp , uint16_t seq )
{
int probation = 0 ;
ast_debug ( 1 , " %p -- probation = %d, seq = %d \n " , rtp , rtp - > learning_probation , seq ) ;
probation = 1 ;
if ( seq = = rtp - > learning_max_seq + 1 ) {
/* packet is in sequence */
rtp - > learning_probation - - ;
rtp - > learning_max_seq = seq ;
if ( rtp - > learning_probation = = 0 ) {
probation = 0 ;
}
} else {
rtp - > learning_probation = learning_min_sequential - 1 ;
rtp - > learning_max_seq = seq ;
}
return probation ;
}
static int ast_rtp_new ( struct ast_rtp_instance * instance ,
struct ast_sched_context * sched , struct ast_sockaddr * addr ,
void * data )
@ -476,6 +532,9 @@ static int ast_rtp_new(struct ast_rtp_instance *instance,
rtp - > ssrc = ast_random ( ) ;
rtp - > seqno = ast_random ( ) & 0xffff ;
rtp - > strict_rtp_state = ( strictrtp ? STRICT_RTP_LEARN : STRICT_RTP_OPEN ) ;
if ( strictrtp ) {
rtp_learning_seq_init ( rtp , ( uint16_t ) rtp - > seqno ) ;
}
/* Create a new socket for us to listen on and use */
if ( ( rtp - > s =
@ -2082,7 +2141,17 @@ static struct ast_frame *ast_rtp_read(struct ast_rtp_instance *instance, int rtc
/* If strict RTP protection is enabled see if we need to learn the remote address or if we need to drop the packet */
if ( rtp - > strict_rtp_state = = STRICT_RTP_LEARN ) {
ast_debug ( 1 , " %p -- start learning mode pass with addr = %s \n " , rtp , ast_sockaddr_stringify ( & addr ) ) ;
/* For now, we always copy the address. */
ast_sockaddr_copy ( & rtp - > strict_rtp_address , & addr ) ;
/* Send the rtp and the seqno from header to rtp_learning_rtp_seq_update to see whether we can exit or not*/
if ( rtp_learning_rtp_seq_update ( rtp , ntohl ( rtpheader [ 0 ] ) ) ) {
ast_debug ( 1 , " %p -- Condition for learning hasn't exited, so reject the frame. \n " , rtp ) ;
return & ast_null_frame ;
}
ast_debug ( 1 , " %p -- Probation Ended. Set strict_rtp_state to STRICT_RTP_CLOSED with address %s \n " , rtp , ast_sockaddr_stringify ( & addr ) ) ;
rtp - > strict_rtp_state = STRICT_RTP_CLOSED ;
} else if ( rtp - > strict_rtp_state = = STRICT_RTP_CLOSED ) {
if ( ast_sockaddr_cmp ( & rtp - > strict_rtp_address , & addr ) ) {
@ -2497,6 +2566,7 @@ static void ast_rtp_remote_address_set(struct ast_rtp_instance *instance, struct
if ( strictrtp ) {
rtp - > strict_rtp_state = STRICT_RTP_LEARN ;
rtp_learning_seq_init ( rtp , rtp - > seqno ) ;
}
return ;
@ -2884,6 +2954,7 @@ static int rtp_reload(int reload)
rtpend = DEFAULT_RTP_END ;
dtmftimeout = DEFAULT_DTMF_TIMEOUT ;
strictrtp = STRICT_RTP_CLOSED ;
learning_min_sequential = DEFAULT_LEARNING_MIN_SEQUENTIAL ;
if ( cfg ) {
if ( ( s = ast_variable_retrieve ( cfg , " general " , " rtpstart " ) ) ) {
rtpstart = atoi ( s ) ;
@ -2927,6 +2998,12 @@ static int rtp_reload(int reload)
if ( ( s = ast_variable_retrieve ( cfg , " general " , " strictrtp " ) ) ) {
strictrtp = ast_true ( s ) ;
}
if ( ( s = ast_variable_retrieve ( cfg , " general " , " probation " ) ) ) {
if ( ( sscanf ( s , " %d " , & learning_min_sequential ) < = 0 ) | | learning_min_sequential < = 0 ) {
ast_log ( LOG_WARNING , " Value for 'probation' could not be read, using default of '%d' instead \n " ,
DEFAULT_LEARNING_MIN_SEQUENTIAL ) ;
}
}
ast_config_destroy ( cfg ) ;
}
if ( rtpstart > = rtpend ) {
Jonathan Rose
14 years ago