Ethereal-dev: [ethereal-dev] Dissector for the Session Announcement Protocol (SAP)
I have added a dissector for the Session Announcement Protocol
(SAP) which is responsible for bringing you the multicast session
advertisements that the sdr program displays.
The document I based my work on is the Internet-Draft
draft-ietf-mmusic-sap-v2-03.txt
The actual dissector file is available from
http://www.cs.tut.fi/~hessu/packet-sap.c
and the patch below adds the necessary things I had to add to the
other files. There is also a fix for a typo in packet-ip.c. The
core of the sap dissector file was copied from packet-tftp.c
Big thanks to Jason Lango for being able to use his SDP
dissector :)
Now the worries. Is there a clean way to access the IP header
information from the UDP dissector? Dissecting a packet as a SAP
packet is only meaningful if the packet was sent to a multicast IP
address. Currently my dissector does not (can not?) check the
destination IP address and will also feed the unicast IP/UDP
packets to the SAP dissector if the destination UDP port is 9875.
Also I'm worrying if I got all the things right in my patch and
the dissector file. If everything looks acceptable, I would like
to add a couple of more protocol dissectors later.
? ethereal/packet-sap.c
Index: ethereal/Makefile.am
===================================================================
RCS file: /cvsroot/ethereal/Makefile.am,v
retrieving revision 1.108
diff -u -r1.108 Makefile.am
--- Makefile.am 1999/11/15 14:17:17 1.108
+++ Makefile.am 1999/11/16 22:33:40
@@ -114,6 +114,7 @@
packet-rtsp.c \
packet-rx.c \
packet-rx.h \
+ packet-sap.c \
packet-sdp.c \
packet-smb.c \
packet-sna.c \
Index: ethereal/packet-ip.c
===================================================================
RCS file: /cvsroot/ethereal/packet-ip.c,v
retrieving revision 1.61
diff -u -r1.61 packet-ip.c
--- packet-ip.c 1999/11/02 07:06:07 1.61
+++ packet-ip.c 1999/11/16 22:33:40
@@ -1212,7 +1212,7 @@
strcpy(type_str, "PIM");
break;
case IGMP_V2_M_RPT:
- strcpy(type_str, "Host reponse (v2)");
+ strcpy(type_str, "Host response (v2)");
break;
case IGMP_MTRC_RESP:
strcpy(type_str, "Traceroute response");
Index: ethereal/packet-udp.c
===================================================================
RCS file: /cvsroot/ethereal/packet-udp.c,v
retrieving revision 1.34
diff -u -r1.34 packet-udp.c
--- packet-udp.c 1999/11/14 20:44:51 1.34
+++ packet-udp.c 1999/11/16 22:33:40
@@ -80,6 +80,7 @@
#define UDP_PORT_RADACCT_NEW 1813
#define UDP_PORT_ICP 3130
#define UDP_PORT_ICQ 4000
+#define UDP_PORT_SAP 9875
#define UDP_PORT_RX_LOW 7000
#define UDP_PORT_RX_HIGH 7009
#define UDP_PORT_RX_AFS_BACKUPS 7021
@@ -169,6 +170,7 @@
udp_hash_add(UDP_PORT_BOOTPS, dissect_bootp);
udp_hash_add(UDP_PORT_TFTP, dissect_tftp);
+ udp_hash_add(UDP_PORT_SAP, dissect_sap);
}
Index: ethereal/packet.h
===================================================================
RCS file: /cvsroot/ethereal/packet.h,v
retrieving revision 1.141
diff -u -r1.141 packet.h
--- packet.h 1999/11/15 14:17:20 1.141
+++ packet.h 1999/11/16 22:33:40
@@ -415,6 +415,10 @@
ETT_RSVP_ADSPEC_SUBTREE2,
ETT_RSVP_ADSPEC_SUBTREE3,
ETT_RTSP,
+ ETT_SAP,
+ ETT_SAP_FLAGS,
+ ETT_SAP_AUTH,
+ ETT_SAP_AUTHF,
ETT_SDP,
ETT_RADIUS,
ETT_RADIUS_AVP,
@@ -643,6 +647,7 @@
void dissect_rsvp(const u_char *, int, frame_data *, proto_tree *);
void dissect_rtsp(const u_char *, int, frame_data *, proto_tree *);
void dissect_rx(const u_char *, int, frame_data *, proto_tree *);
+void dissect_sap(const u_char *, int, frame_data *, proto_tree *);
void dissect_sdp(const u_char *, int, frame_data *, proto_tree *);
void dissect_sna(const u_char *, int, frame_data *, proto_tree *);
void dissect_snmp(const u_char *, int, frame_data *, proto_tree *);
// Heikki
--
Heikki Vatiainen * hessu@xxxxxxxxx
Tampere University of Technology * Tampere, Finland
