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Merge in strictrtp branch. This adds a strictrtp option to rtp.conf which drops packets that do not come from the remote party. 

(closes issue #8952)
Reported by: amorsen


git-svn-id: http://svn.digium.com/svn/asterisk/trunk@100206 f38db490-d61c-443f-a65b-d21fe96a405b
This commit is contained in:
file 2008-01-24 17:47:50 +00:00
parent 860bb66a0e
commit 341f67c198
3 changed files with 39 additions and 0 deletions
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2
CHANGES
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@ -500,3 +500,5 @@ Miscellaneous
specifying which socket to use to connect to the running Asterisk daemon
(-s)
* Added logging to 'make update' command. See update.log
* Added strictrtp option to rtp.conf. If enabled this will drop RTP packets that
do not come from the remote party.

4
configs/rtp.conf.sample
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@ -20,3 +20,7 @@ rtpend=20000
;dtmftimeout=3000
; rtcpinterval = 5000 ; Milliseconds between rtcp reports
;(min 500, max 60000, default 5000)
;
; Enable strict RTP protection. This will drop RTP packets that
; do not come from the source of the RTP stream.
; strictrtp=yes

33
main/rtp.c
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@ -78,6 +78,13 @@ static struct sockaddr_in rtcpdebugaddr; /*!< Debug RTCP packets to/from this ho
#ifdef SO_NO_CHECK
static int nochecksums;
#endif
static int strictrtp;
enum strict_rtp_state {
STRICT_RTP_OPEN = 0, /*! No RTP packets should be dropped, all sources accepted */
STRICT_RTP_LEARN, /*! Accept next packet as source */
STRICT_RTP_CLOSED, /*! Drop all RTP packets not coming from source that was learned */
};
/* Uncomment this to enable more intense native bridging, but note: this is currently buggy */
/* #define P2P_INTENSE */
@ -165,6 +172,9 @@ struct ast_rtp {
struct ast_rtcp *rtcp;
struct ast_codec_pref pref;
struct ast_rtp *bridged; /*!< Who we are Packet bridged to */
enum strict_rtp_state strict_rtp_state; /*!< Current state that strict RTP protection is in */
struct sockaddr_in strict_rtp_address; /*!< Remote address information for strict RTP purposes */
};
/* Forward declarations */
@ -1391,6 +1401,21 @@ struct ast_frame *ast_rtp_read(struct ast_rtp *rtp)
res = recvfrom(rtp->s, rtp->rawdata + AST_FRIENDLY_OFFSET, sizeof(rtp->rawdata) - AST_FRIENDLY_OFFSET,
0, (struct sockaddr *)&sin, &len);
/* If strict RTP protection is enabled see if we need to learn this address or if the packet should be dropped */
if (rtp->strict_rtp_state == STRICT_RTP_LEARN) {
/* Copy over address that this packet was received on */
memcpy(&rtp->strict_rtp_address, &sin, sizeof(rtp->strict_rtp_address));
/* Now move over to actually protecting the RTP port */
rtp->strict_rtp_state = STRICT_RTP_CLOSED;
ast_debug(1, "Learned remote address is %s:%d for strict RTP purposes, now protecting the port.\n", ast_inet_ntoa(rtp->strict_rtp_address.sin_addr), ntohs(rtp->strict_rtp_address.sin_port));
} else if (rtp->strict_rtp_state == STRICT_RTP_CLOSED) {
/* If the address we previously learned doesn't match the address this packet came in on simply drop it */
if ((rtp->strict_rtp_address.sin_addr.s_addr != sin.sin_addr.s_addr) || (rtp->strict_rtp_address.sin_port != sin.sin_port)) {
ast_debug(1, "Received RTP packet from %s:%d, dropping due to strict RTP protection. Expected it to be from %s:%d\n", ast_inet_ntoa(sin.sin_addr), ntohs(sin.sin_port), ast_inet_ntoa(rtp->strict_rtp_address.sin_addr), ntohs(rtp->strict_rtp_address.sin_port));
return &ast_null_frame;
}
}
rtpheader = (unsigned int *)(rtp->rawdata + AST_FRIENDLY_OFFSET);
if (res < 0) {
if (errno == EBADF)
@ -2191,6 +2216,7 @@ void ast_rtp_new_init(struct ast_rtp *rtp)
rtp->ssrc = ast_random();
rtp->seqno = ast_random() & 0xffff;
ast_set_flag(rtp, FLAG_HAS_DTMF);
rtp->strict_rtp_state = (strictrtp ? STRICT_RTP_LEARN : STRICT_RTP_OPEN);
return;
}
@ -2312,6 +2338,9 @@ void ast_rtp_set_peer(struct ast_rtp *rtp, struct sockaddr_in *them)
rtp->rtcp->them.sin_addr = them->sin_addr;
}
rtp->rxseqno = 0;
/* If strict RTP protection is enabled switch back to the learn state so we don't drop packets from above */
if (strictrtp)
rtp->strict_rtp_state = STRICT_RTP_LEARN;
}
int ast_rtp_get_peer(struct ast_rtp *rtp, struct sockaddr_in *them)
@ -4025,6 +4054,7 @@ static int __ast_rtp_reload(int reload)
rtpstart = 5000;
rtpend = 31000;
dtmftimeout = DEFAULT_DTMF_TIMEOUT;
strictrtp = STRICT_RTP_OPEN;
if (cfg) {
if ((s = ast_variable_retrieve(cfg, "general", "rtpstart"))) {
rtpstart = atoi(s);
@ -4068,6 +4098,9 @@ static int __ast_rtp_reload(int reload)
dtmftimeout = DEFAULT_DTMF_TIMEOUT;
};
}
if ((s = ast_variable_retrieve(cfg, "general", "strictrtp"))) {
strictrtp = ast_true(s);
}
ast_config_destroy(cfg);
}
if (rtpstart >= rtpend) {