Go to file
guy 6c6b1ac0b2 If we run out of data in the when processing tagged parameters, return
"success", not "failure" - there's no special "end of list" parameter.
Get rid of the check for a parameter tag of 0xff, for the same reason.

Take out an extra space between the "[" and the list of rates in a
"supported rates" tagged parameter, and don't print the "[" or the "
Mbit]", or the leading space if there are no supported rates (or there
is no "supported rates" parameter.

Use "fn_print" to print the SSID, in case there are non-printable
characters in it.

Show the channel number in decimal, not hex, as that's how it's given in
the IEEE 802.11 spec.

Show the supported rates in a probe response, if present.

Get rid of random extra trailing space in tagged parameter output.
2002-05-13 08:30:19 +00:00
lbl Remove from "lbl/os-solaris2.h" declarations of functions we don't use; 2000-10-11 04:02:15 +00:00
missing Patch from Pekka Savola <pekkas@netcore.fi> to get rid of "savestr()" 2001-01-20 07:22:20 +00:00
.cvsignore Add auto-running of autoheader and autoconf and configure (from autoconf.info) 2000-01-15 00:43:16 +00:00
acconfig.h From Maciej W. Rozycki <macro@ds2.pg.gda.pl>: 2002-04-07 02:09:04 +00:00
aclocal.m4 Nobody seemed to know why we preferred sigset() to sigaction(); the 2002-04-24 06:34:18 +00:00
addrtoname.c From Heinz-Ado Arnolds <Ado.Arnolds@dhm-systems.de>: 2001-11-25 01:48:46 +00:00
addrtoname.h Eliminate some unused parameters. 2001-09-17 21:57:50 +00:00
ah.h move ah/esp struct declratiaon into separate header (ah.h and esp.h). 2000-10-06 11:32:17 +00:00
appletalk.h always use u_intXX_t for protocol format declaration. char/short/int may not 2000-10-03 02:54:54 +00:00
arcnet.h ARCNet support, from NetBSD. 2001-04-17 08:39:17 +00:00
atime.awk Initial revision 1999-10-07 23:47:09 +00:00
bootp.h Add NDS tags 62 and 63 from RFC 2242. 2001-01-09 07:39:13 +00:00
bpf_dump.c Allow tcpdump to work with earlier libpcaps. 2000-12-09 02:58:45 +00:00
CHANGES ChangeLog for 3.7 done from CVS logs. 2002-01-21 11:03:33 +00:00
chdlc.h Add support for NetBSD DLT_PPP_SERIAL (PPP in HDLC-like framing, as per 2000-09-18 05:11:43 +00:00
config.guess newest config.guess and config.sub from ftp://sunsite.utk.edu/pub/gnu/ftp/config/ 2001-05-05 20:53:51 +00:00
config.h.in From Maciej W. Rozycki <macro@ds2.pg.gda.pl>: 2002-04-07 02:16:03 +00:00
config.sub newest config.guess and config.sub from ftp://sunsite.utk.edu/pub/gnu/ftp/config/ 2001-05-05 20:53:51 +00:00
configure Regenerate. 2002-04-25 04:26:45 +00:00
configure.in From Maciej W. Rozycki <macro@ds2.pg.gda.pl>: 2002-04-07 02:16:03 +00:00
CREDITS If we run out of data in the when processing tagged parameters, return 2002-05-13 08:30:19 +00:00
decnet.h always use u_intXX_t for protocol format declaration. char/short/int may not 2000-10-03 02:54:54 +00:00
esp.h move ah/esp struct declratiaon into separate header (ah.h and esp.h). 2000-10-06 11:32:17 +00:00
ether.h Some compilers may pad structures to a length that's a multiple of 2 or 2000-10-09 03:24:24 +00:00
ethertype.h MPLS label encapsulation decoding, per RFC3032. 2001-06-21 17:56:02 +00:00
extract.h Eliminate some unused parameters. 2001-09-17 21:57:50 +00:00
fddi.h Some compilers may pad structures to a length that's a multiple of 2 or 2000-10-09 02:59:39 +00:00
FILES Include code to handle OpenBSD DLT_PFLOG files, based on the OpenBSD 2002-02-05 10:07:38 +00:00
gmt2local.c remove gnuc.h and __dead 2000-07-11 00:49:02 +00:00
gmt2local.h Initial revision 1999-10-07 23:47:09 +00:00
icmp6.h Updates from Kazushi Sugyo <sugyo@pb.jp.nec.com> for 2002-03-28 10:02:34 +00:00
ieee802_11.h Don't use "sizeof" to compute the sizes of various headers - the 2001-06-14 09:50:01 +00:00
igrp.h Give a bunch of files RCS and SCCS IDs. 2000-12-17 23:07:48 +00:00
INSTALL The stuff in the "linux-include" directory is no longer needed, as we no 2000-12-16 09:07:45 +00:00
install-sh Initial revision 1999-10-07 23:47:09 +00:00
interface.h "espsecret_xform" and "espsecret_key" are static to "print-esp.c"; don't 2002-04-25 04:31:42 +00:00
ip6.h Give a bunch of files RCS and SCCS IDs. 2000-12-17 23:07:48 +00:00
ip.h C bitfields are no longer being used to extract bit fields from the IP 2000-10-03 09:17:40 +00:00
ipsec_doi.h sync with kame header. remove unofficial number (V42bis compression for IPComp). 2000-10-04 03:00:29 +00:00
ipx.h Don't declare an object of type "struct ipxHdr" - the object isn't used. 2002-03-05 11:35:45 +00:00
isakmp.h don't try to chase unaligned pointer. 2000-10-03 05:16:38 +00:00
l2tp.h L2TP dissector changes, from Motonori Shindo: 2001-11-05 10:03:27 +00:00
lane.h always use u_intXX_t for protocol format declaration. char/short/int may not 2000-10-03 02:54:54 +00:00
LICENSE added license file 2000-10-09 22:38:24 +00:00
llc.h Support RFC 2684 bridging of Ethernet, 802.5 Token Ring, and FDDI, and 2002-04-07 09:50:30 +00:00
machdep.c Declare "snprintf()" if we are pulling in our own "snprintf()", so that 2001-06-27 05:42:04 +00:00
machdep.h s/sprintf/snprintf/. 2000-01-17 06:24:23 +00:00
Makefile-devel-adds Add auto-running of autoheader and autoconf and configure (from autoconf.info) 2000-01-15 00:43:16 +00:00
Makefile.in Include code to handle OpenBSD DLT_PFLOG files, based on the OpenBSD 2002-02-05 10:07:38 +00:00
makemib Update makemib and print-snmp.c license, via OpenBSD: jakob got 2001-09-17 22:16:52 +00:00
mib.h patches to help build on Linux 2.2 1999-10-17 21:37:10 +00:00
mkdep Initial revision 1999-10-07 23:47:09 +00:00
nameser.h Yet *another* #define of ours that an OS also defines; in this case it's 2001-06-27 05:40:16 +00:00
netbios.h Initial revision 1999-10-07 23:47:09 +00:00
nfs.h s/nfstype/nfs_type/ to avoid conflict with system header files 2000-07-29 08:05:04 +00:00
nfsfh.h Get rid of casts of pointers-to-const to pointers-to-nonconst. 2002-04-24 06:27:05 +00:00
ntp.h always use u_intXX_t for protocol format declaration. char/short/int may not 2000-10-03 02:54:54 +00:00
oakley.h Bring in KAME IPv6 tcpdump. replaces esp/ah/isakmp decoder. 1999-10-30 05:11:06 +00:00
ospf6.h Give a bunch of files RCS and SCCS IDs. 2000-12-17 23:07:48 +00:00
ospf.h Give a bunch of files RCS and SCCS IDs. 2000-12-17 23:07:48 +00:00
packetdat.awk Initial revision 1999-10-07 23:47:09 +00:00
parsenfsfh.c Get rid of casts of pointers-to-const to pointers-to-nonconst. 2002-04-24 06:27:05 +00:00
PLATFORMS updates for 3.7. 2002-01-21 11:16:32 +00:00
ppp.h Always define PPP_COMP. 2001-02-04 02:17:54 +00:00
print-802_11.c If we run out of data in the when processing tagged parameters, return 2002-05-13 08:30:19 +00:00
print-ah.c Eliminate some unused parameters. 2001-09-17 21:57:50 +00:00
print-arcnet.c Eliminate some unused parameters. 2001-09-17 21:57:50 +00:00
print-arp.c Make "ar_sha()", "ar_spa()", "ar_tha()", and "ar_tpa()" return "const 2002-04-25 04:37:31 +00:00
print-ascii.c "-A" flag to print packet data in ASCII, from Jørgen Thomsen 2002-04-24 06:55:54 +00:00
print-atalk.c Check for a too-small NBP length before subtracting the header size 2002-02-05 10:03:34 +00:00
print-atm.c Note that we should perhaps also, in the heuristic test for a Fore 802.6 2002-04-07 10:05:40 +00:00
print-beep.c The BXXP protocol was replaced by the BEEP protocol; replace the BXXP 2001-12-10 08:21:22 +00:00
print-bgp.c add new bgp option type, "capabilities advertisement". 2001-10-18 09:52:17 +00:00
print-bootp.c Make the tag in "rfc1048_print()" a 16-bit variable, as 16-bit 2002-04-26 04:59:08 +00:00
print-cdp.c Another bug fix from Gert Doering. 2002-04-26 09:51:34 +00:00
print-chdlc.c Eliminate some unused parameters. 2001-09-17 21:57:50 +00:00
print-cip.c There's no link-layer header on Linux ARPHRD_ATM packets; there's 2001-09-23 21:52:38 +00:00
print-cnfp.c Eliminate some unused parameters. 2001-09-17 21:57:50 +00:00
print-decnet.c From Maciej W. Rozycki <macro@ds2.pg.gda.pl>: 2002-04-07 02:09:04 +00:00
print-dhcp6.c Fix a cast to use the correct type. 2002-01-19 08:05:54 +00:00
print-domain.c Get rid of a null-pointer dereference when dissecting DNS requests with 2001-10-19 09:00:48 +00:00
print-dvmrp.c Don't print multiple lines for a single packet unless -vv 2001-05-10 05:30:20 +00:00
print-egp.c Eliminate some unused parameters. 2001-09-17 21:57:50 +00:00
print-esp.c From Maciej W. Rozycki <macro@ds2.pg.gda.pl>: 2002-04-07 02:16:03 +00:00
print-ether.c Support RFC 2684 bridging of Ethernet, 802.5 Token Ring, and FDDI, and 2002-04-07 09:50:30 +00:00
print-fddi.c Support RFC 2684 bridging of Ethernet, 802.5 Token Ring, and FDDI, and 2002-04-07 09:50:30 +00:00
print-frag6.c Eliminate some unused parameters. 2001-09-17 21:57:50 +00:00
print-gre.c Remove #if 0 sections 2001-06-15 22:17:31 +00:00
print-hsrp.c Cosmetic TCHECK() change. 2002-05-07 18:31:49 +00:00
print-icmp6.c -Wunused 2002-04-02 02:57:39 +00:00
print-icmp.c From Nathaniel Couper-Noles <Nathaniel@isi1.tccisi.com>: print the 2001-10-27 07:21:34 +00:00
print-igmp.c Eliminate some unused parameters. 2001-09-17 21:57:50 +00:00
print-igrp.c Remove #if 0 sections 2001-06-15 22:17:31 +00:00
print-ip6.c remove comment which may not be correct; i've experienced unaligned header 2001-11-16 02:17:36 +00:00
print-ip6opts.c Updates from Kazushi Sugyo <sugyo@pb.jp.nec.com> for 2002-03-28 10:02:34 +00:00
print-ip.c remove comment which may not be correct; i've experienced unaligned header 2001-11-16 02:17:36 +00:00
print-ipcomp.c print SPI in hex. 2000-12-12 09:58:40 +00:00
print-ipx.c From Heinz-Ado Arnolds <Ado.Arnolds@dhm-systems.de>: 2001-11-25 01:48:46 +00:00
print-isakmp.c do not subtract size of the field twice. from kame 2001-10-26 03:41:29 +00:00
print-isoclns.c From Hannes Gredler: support for the IP-Reach-subTLV #2 and 2002-04-30 09:04:35 +00:00
print-krb.c Get rid of includes of <netinet/in_systm.h>, and replace "n_short", 2000-09-29 04:58:33 +00:00
print-l2tp.c Squelch a compiler warning. 2001-11-10 21:37:58 +00:00
print-lane.c Put the infodelay wrapping into the remaining "XXX_if_print()" routines. 2001-07-05 18:54:13 +00:00
print-lcp.c Get rid of some includes of <net/route.h>, and empty declarations of 2000-10-06 04:23:10 +00:00
print-llc.c Support RFC 2684 bridging of Ethernet, 802.5 Token Ring, and FDDI, and 2002-04-07 09:50:30 +00:00
print-lwres.c Move all the "undefine so that the compiler doesn't whine about 2001-06-26 06:19:03 +00:00
print-mobile.c Use the passed in length instead of the IP header's length in the 2001-08-20 17:53:53 +00:00
print-mpls.c Print the whole MPLS label stack. 2002-05-07 18:35:39 +00:00
print-msdp.c Include <netinet/in.h> to declare "ntohs()"; include <stdlib.h> and 2001-12-10 08:06:40 +00:00
print-netbios.c Get rid of includes of <netinet/in_systm.h>, and replace "n_short", 2000-09-29 04:58:33 +00:00
print-nfs.c Get rid of casts of pointers-to-const to pointers-to-nonconst. 2002-04-24 06:27:05 +00:00
print-ntp.c Cast the argument to "fn_printn()" to "u_char *", as that's the argument 2002-04-25 04:57:59 +00:00
print-null.c Put the infodelay wrapping into the remaining "XXX_if_print()" routines. 2001-07-05 18:54:13 +00:00
print-ospf6.c Quiet down gcc -Wall 2001-05-09 01:08:03 +00:00
print-ospf.c Don't print "nbrs" if no neighbor list will follow. 2001-06-28 04:34:51 +00:00
print-pflog.c Include "config.h" before including anything else. 2002-02-06 11:05:35 +00:00
print-pim.c Handle old DR-priority and old Bidir-capable option values. 2002-05-07 18:28:38 +00:00
print-ppp.c print protocol type (LCP/IPCP/whatever) even if -e is not specified. 2001-10-24 03:49:19 +00:00
print-pppoe.c Put the infodelay wrapping into the remaining "XXX_if_print()" routines. 2001-07-05 18:54:13 +00:00
print-pptp.c Small PPTP fix from Motonori Shindo. 2001-10-31 08:54:31 +00:00
print-radius.c Include <time.h>, if possible, to declare "ctime()". 2002-04-20 09:40:42 +00:00
print-raw.c Put the infodelay wrapping into the remaining "XXX_if_print()" routines. 2001-07-05 18:54:13 +00:00
print-rip.c Don't print multiple lines for a single packet unless -vv 2001-05-10 05:30:20 +00:00
print-ripng.c clarify some signedness mixup 2001-11-16 08:59:21 +00:00
print-rt6.c Remove #if 0 sections 2001-06-15 22:17:31 +00:00
print-rx.c Squelch some compiler warnings caused by passing "char *"s rather than 2002-04-30 06:45:08 +00:00
print-sctp.c Constify. 2002-04-25 04:45:59 +00:00
print-sl.c Put the infodelay wrapping into the remaining "XXX_if_print()" routines. 2001-07-05 18:54:13 +00:00
print-sll.c Put the infodelay wrapping into the remaining "XXX_if_print()" routines. 2001-07-05 18:54:13 +00:00
print-smb.c From Sami Farin <safari@iki.fi>: put in a missing blank before "NBT 2002-04-30 09:09:41 +00:00
print-snmp.c Fix spacing with -v 2002-05-07 18:27:40 +00:00
print-stp.c Get rid of includes of <netinet/in_systm.h>, and replace "n_short", 2000-09-29 04:58:33 +00:00
print-sunrpc.c put stripped-down version of ip6.h and icmp6.h into tcpdump tree. 2000-10-07 05:53:09 +00:00
print-tcp.c The BXXP protocol was replaced by the BEEP protocol; replace the BXXP 2001-12-10 08:21:22 +00:00
print-telnet.c Fix truncation checks. It checked the TCP packet length but not the 2001-09-10 06:40:08 +00:00
print-tftp.c Switch to config.h instead of passing defines in DEFS. 1999-11-21 09:36:43 +00:00
print-timed.c From Guy: include <netinet/in.h> for ntohl() on HP-UX 11.00 2001-05-17 18:33:23 +00:00
print-token.c Support RFC 2684 bridging of Ethernet, 802.5 Token Ring, and FDDI, and 2002-04-07 09:50:30 +00:00
print-udp.c print "addr > addr" correctly again. 2001-12-03 02:06:10 +00:00
print-vjc.c Pull the "linux-include" versions of "slip.h" and "slcompress.h" up to 2000-10-09 01:53:19 +00:00
print-vrrp.c Pass the length of the authentication data to print_fn, instead of 2001-07-23 22:27:30 +00:00
print-wb.c *Another* #define that's also defined by some OS; in this case, it's 2001-06-27 05:37:19 +00:00
print-zephyr.c Add a cast to squelch a compiler complaint - and remove a potential 2002-04-27 23:39:25 +00:00
README updates for 3.7. 2002-01-21 11:16:32 +00:00
route6d.h copyright clarification 2001-10-22 04:27:47 +00:00
rx.h copyright clarification. 2001-10-22 04:23:37 +00:00
sctpConstants.h Give a bunch of header files RCS and SCCS IDs. 2001-06-28 10:17:21 +00:00
sctpHeader.h Some platforms, e.g. some versions of AIX, appear not to define "struct 2001-08-01 03:34:00 +00:00
send-ack.awk Initial revision 1999-10-07 23:47:09 +00:00
setsignal.c remove gnuc.h and __dead 2000-07-11 00:49:02 +00:00
setsignal.h Initial revision 1999-10-07 23:47:09 +00:00
slcompress.h Get rid of a couple of #defines not used by tcpdump. 2000-10-09 02:03:44 +00:00
slip.h Pull the "linux-include" versions of "slip.h" and "slcompress.h" up to 2000-10-09 01:53:19 +00:00
sll.h It's a bit more convenient for Ethereal if the "sll_protocol" field is 2000-12-23 07:52:11 +00:00
smb.h Bill Fenner's changes to clean up the SMB dissection somewhat and to add 2002-01-17 04:38:29 +00:00
smbutil.c Add some casts to squelch compiler complaints (and remove potential 2002-04-26 05:12:40 +00:00
stime.awk Initial revision 1999-10-07 23:47:09 +00:00
strcasecmp.c Unify rcsid[]'s. 2000-01-09 21:34:14 +00:00
tcp.h Move some stuff that tried to make up for system headers from print-tcp.c 2001-05-09 01:16:57 +00:00
tcpdump.1 Fix a formatto. 2002-05-07 04:00:09 +00:00
tcpdump.c "-A" flag to print packet data in ASCII, from Jørgen Thomsen 2002-04-24 06:55:54 +00:00
telnet.h Eliminate some unused parameters. 2001-09-17 21:57:50 +00:00
timed.h Give a bunch of files RCS and SCCS IDs. 2000-12-17 23:07:48 +00:00
TODO We already added DLT_LINUX_COOKED, except it's called DLT_LINUX_SLL, and 2001-01-03 19:37:18 +00:00
token.h always use u_intXX_t for protocol format declaration. char/short/int may not 2000-10-03 02:54:54 +00:00
udp.h always use u_intXX_t for protocol format declaration. char/short/int may not 2000-10-03 02:54:54 +00:00
util.c Introduce tok2strary(), similar to tok2str() except it takes an 2001-10-08 16:12:12 +00:00
VERSION updates for 3.7. 2002-01-21 11:16:32 +00:00
vfprintf.c remove non-STDC code 2000-07-01 03:38:59 +00:00

@(#) $Header: /tcpdump/master/tcpdump/README,v 1.60 2002-01-21 11:16:33 mcr Exp $ (LBL)

TCPDUMP 3.7.1
Now maintained by "The Tcpdump Group"
See 		www.tcpdump.org

Please send inquiries/comments/reports to 	tcpdump-workers@tcpdump.org

Anonymous CVS is available via:
	cvs -d cvs.tcpdump.org:/tcpdump/master login
	(password "anoncvs")
	cvs -d cvs.tcpdump.org:/tcpdump/master checkout tcpdump

Version 3.7.1 of TCPDUMP can be retrived with the CVS tag "tcpdump_3_7rel1":
	cvs -d cvs.tcpdump.org:/tcpdump/master checkout -r tcpdump_3_7rel1 tcpdump

Please send patches against the master copy to patches@tcpdump.org.

formerly from 	Lawrence Berkeley National Laboratory
		Network Research Group <tcpdump@ee.lbl.gov>
		ftp://ftp.ee.lbl.gov/tcpdump.tar.Z (3.4)

This directory contains source code for tcpdump, a tool for network
monitoring and data acquisition.  This software was originally
developed by the Network Research Group at the Lawrence Berkeley
National Laboratory.  The original distribution is available via
anonymous ftp to ftp.ee.lbl.gov, in tcpdump.tar.Z.  More recent
development is performed at tcpdump.org, http://www.tcpdump.org/

Tcpdump uses libpcap, a system-independent interface for user-level
packet capture.  Before building tcpdump, you must first retrieve and
build libpcap, also originally from LBL and now being maintained by
tcpdump.org; see http://www.tcpdump.org/ .

Once libpcap is built (either install it or make sure it's in
../libpcap), you can build tcpdump using the procedure in the INSTALL
file.

The program is loosely based on SMI's "etherfind" although none of the
etherfind code remains.  It was originally written by Van Jacobson as
part of an ongoing research project to investigate and improve tcp and
internet gateway performance.  The parts of the program originally
taken from Sun's etherfind were later re-written by Steven McCanne of
LBL.  To insure that there would be no vestige of proprietary code in
tcpdump, Steve wrote these pieces from the specification given by the
manual entry, with no access to the source of tcpdump or etherfind.

Over the past few years, tcpdump has been steadily improved by the
excellent contributions from the Internet community (just browse
through the CHANGES file).  We are grateful for all the input.

Richard Stevens gives an excellent treatment of the Internet protocols
in his book ``TCP/IP Illustrated, Volume 1''. If you want to learn more
about tcpdump and how to interpret its output, pick up this book.

Some tools for viewing and analyzing tcpdump trace files are available
from the Internet Traffic Archive:

	http://www.acm.org/sigcomm/ITA/

Another tool that tcpdump users might find useful is tcpslice:

	ftp://ftp.ee.lbl.gov/tcpslice.tar.Z

It is a program that can be used to extract portions of tcpdump binary
trace files. See the above distribution for further details and
documentation.

Problems, bugs, questions, desirable enhancements, etc. 
should be sent to the address "tcpdump-workers@tcpdump.org".

Source code contributions, etc. should be sent to the email address 
"patches@tcpdump.org".

Current versions can be found at www.tcpdump.org

 - The TCPdump team

original text by: Steve McCanne, Craig Leres, Van Jacobson

-------------------------------------
This directory also contains some short awk programs intended as
examples of ways to reduce tcpdump data when you're tracking
particular network problems:

send-ack.awk
	Simplifies the tcpdump trace for an ftp (or other unidirectional
	tcp transfer).  Since we assume that one host only sends and
	the other only acks, all address information is left off and
	we just note if the packet is a "send" or an "ack".

	There is one output line per line of the original trace.
	Field 1 is the packet time in decimal seconds, relative
	to the start of the conversation.  Field 2 is delta-time
	from last packet.  Field 3 is packet type/direction.
	"Send" means data going from sender to receiver, "ack"
	means an ack going from the receiver to the sender.  A
	preceding "*" indicates that the data is a retransmission.
	A preceding "-" indicates a hole in the sequence space
	(i.e., missing packet(s)), a "#" means an odd-size (not max
	seg size) packet.  Field 4 has the packet flags
	(same format as raw trace).  Field 5 is the sequence
	number (start seq. num for sender, next expected seq number
	for acks).  The number in parens following an ack is
	the delta-time from the first send of the packet to the
	ack.  A number in parens following a send is the
	delta-time from the first send of the packet to the
	current send (on duplicate packets only).  Duplicate
	sends or acks have a number in square brackets showing
	the number of duplicates so far.

	Here is a short sample from near the start of an ftp:
		3.00    0.20   send . 512
		3.20    0.20    ack . 1024  (0.20)
		3.20    0.00   send P 1024
		3.40    0.20    ack . 1536  (0.20)
		3.80    0.40 * send . 0  (3.80) [2]
		3.82    0.02 *  ack . 1536  (0.62) [2]
	Three seconds into the conversation, bytes 512 through 1023
	were sent.  200ms later they were acked.  Shortly thereafter
	bytes 1024-1535 were sent and again acked after 200ms.
	Then, for no apparent reason, 0-511 is retransmitted, 3.8
	seconds after its initial send (the round trip time for this
	ftp was 1sec, +-500ms).  Since the receiver is expecting
	1536, 1536 is re-acked when 0 arrives.

packetdat.awk
	Computes chunk summary data for an ftp (or similar
	unidirectional tcp transfer). [A "chunk" refers to
	a chunk of the sequence space -- essentially the packet
	sequence number divided by the max segment size.]

	A summary line is printed showing the number of chunks,
	the number of packets it took to send that many chunks
	(if there are no lost or duplicated packets, the number
	of packets should equal the number of chunks) and the
	number of acks.

	Following the summary line is one line of information
	per chunk.  The line contains eight fields:
	   1 - the chunk number
	   2 - the start sequence number for this chunk
	   3 - time of first send
	   4 - time of last send
	   5 - time of first ack
	   6 - time of last ack
	   7 - number of times chunk was sent
	   8 - number of times chunk was acked
	(all times are in decimal seconds, relative to the start
	of the conversation.)

	As an example, here is the first part of the output for
	an ftp trace:

	# 134 chunks.  536 packets sent.  508 acks.
	1       1       0.00    5.80    0.20    0.20    4       1
	2       513     0.28    6.20    0.40    0.40    4       1
	3       1025    1.16    6.32    1.20    1.20    4       1
	4       1561    1.86    15.00   2.00    2.00    6       1
	5       2049    2.16    15.44   2.20    2.20    5       1
	6       2585    2.64    16.44   2.80    2.80    5       1
	7       3073    3.00    16.66   3.20    3.20    4       1
	8       3609    3.20    17.24   3.40    5.82    4       11
	9       4097    6.02    6.58    6.20    6.80    2       5

	This says that 134 chunks were transferred (about 70K
	since the average packet size was 512 bytes).  It took
	536 packets to transfer the data (i.e., on the average
	each chunk was transmitted four times).  Looking at,
	say, chunk 4, we see it represents the 512 bytes of
	sequence space from 1561 to 2048.  It was first sent
	1.86 seconds into the conversation.  It was last
	sent 15 seconds into the conversation and was sent
	a total of 6 times (i.e., it was retransmitted every
	2 seconds on the average).  It was acked once, 140ms
	after it first arrived.

stime.awk
atime.awk
	Output one line per send or ack, respectively, in the form
		<time> <seq. number>
	where <time> is the time in seconds since the start of the
	transfer and <seq. number> is the sequence number being sent
	or acked.  I typically plot this data looking for suspicious
	patterns.


The problem I was looking at was the bulk-data-transfer
throughput of medium delay network paths (1-6 sec.  round trip
time) under typical DARPA Internet conditions.  The trace of the
ftp transfer of a large file was used as the raw data source.
The method was:

  - On a local host (but not the Sun running tcpdump), connect to
    the remote ftp.

  - On the monitor Sun, start the trace going.  E.g.,
      tcpdump host local-host and remote-host and port ftp-data >tracefile

  - On local, do either a get or put of a large file (~500KB),
    preferably to the null device (to minimize effects like
    closing the receive window while waiting for a disk write).

  - When transfer is finished, stop tcpdump.  Use awk to make up
    two files of summary data (maxsize is the maximum packet size,
    tracedata is the file of tcpdump tracedata):
      awk -f send-ack.awk packetsize=avgsize tracedata >sa
      awk -f packetdat.awk packetsize=avgsize tracedata >pd

  - While the summary data files are printing, take a look at
    how the transfer behaved:
      awk -f stime.awk tracedata | xgraph
    (90% of what you learn seems to happen in this step).

  - Do all of the above steps several times, both directions,
    at different times of day, with different protocol
    implementations on the other end.

  - Using one of the Unix data analysis packages (in my case,
    S and Gary Perlman's Unix|Stat), spend a few months staring
    at the data.

  - Change something in the local protocol implementation and
    redo the steps above.

  - Once a week, tell your funding agent that you're discovering
    wonderful things and you'll write up that research report
    "real soon now".