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-rw-r--r--docs/tutorials/008/combine.shar465
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--- a/docs/tutorials/008/combine.shar
+++ /dev/null
@@ -1,465 +0,0 @@
-#!/bin/sh
-# This is a shell archive (produced by GNU sharutils 4.2).
-# To extract the files from this archive, save it to some FILE, remove
-# everything before the `!/bin/sh' line above, then type `sh FILE'.
-#
-# Made on 1999-01-26 19:48 EST by <jcej@chiroptera.tragus.org>.
-# Source directory was `/var/home/jcej/projects/ACE_wrappers/docs/tutorials/008'.
-#
-# Existing files will *not* be overwritten unless `-c' is specified.
-#
-# This shar contains:
-# length mode name
-# ------ ---------- ------------------------------------------
-# 515 -rw-rw-r-- hdr
-# 59 -rw-rw-r-- bodies
-# 2769 -rw-rw-r-- page01.pre
-# 416 -rw-rw-r-- page02.pre
-# 345 -rw-rw-r-- page03.pre
-# 481 -rw-rw-r-- page04.pre
-# 578 -rw-rw-r-- page05.pre
-# 952 -rw-rw-r-- page02.pst
-# 367 -rw-rw-r-- page03.pst
-# 1173 -rw-rw-r-- page04.pst
-#
-save_IFS="${IFS}"
-IFS="${IFS}:"
-gettext_dir=FAILED
-locale_dir=FAILED
-first_param="$1"
-for dir in $PATH
-do
- if test "$gettext_dir" = FAILED && test -f $dir/gettext \
- && ($dir/gettext --version >/dev/null 2>&1)
- then
- set `$dir/gettext --version 2>&1`
- if test "$3" = GNU
- then
- gettext_dir=$dir
- fi
- fi
- if test "$locale_dir" = FAILED && test -f $dir/shar \
- && ($dir/shar --print-text-domain-dir >/dev/null 2>&1)
- then
- locale_dir=`$dir/shar --print-text-domain-dir`
- fi
-done
-IFS="$save_IFS"
-if test "$locale_dir" = FAILED || test "$gettext_dir" = FAILED
-then
- echo=echo
-else
- TEXTDOMAINDIR=$locale_dir
- export TEXTDOMAINDIR
- TEXTDOMAIN=sharutils
- export TEXTDOMAIN
- echo="$gettext_dir/gettext -s"
-fi
-touch -am 1231235999 $$.touch >/dev/null 2>&1
-if test ! -f 1231235999 && test -f $$.touch; then
- shar_touch=touch
-else
- shar_touch=:
- echo
- $echo 'WARNING: not restoring timestamps. Consider getting and'
- $echo "installing GNU \`touch', distributed in GNU File Utilities..."
- echo
-fi
-rm -f 1231235999 $$.touch
-#
-if mkdir _sh30434; then
- $echo 'x -' 'creating lock directory'
-else
- $echo 'failed to create lock directory'
- exit 1
-fi
-# ============= hdr ==============
-if test -f 'hdr' && test "$first_param" != -c; then
- $echo 'x -' SKIPPING 'hdr' '(file already exists)'
-else
- $echo 'x -' extracting 'hdr' '(text)'
- sed 's/^X//' << 'SHAR_EOF' > 'hdr' &&
-<HTML>
-<HEAD>
-X <META HTTP-EQUIV="Content-Type" CONTENT="text/html; charset=iso-8859-1">
-X <META NAME="GENERATOR" CONTENT="Mozilla/4.04 [en] (X11; I; Linux 2.0.32 i486) [Netscape]">
-X <META NAME="Author" CONTENT="James CE Johnson">
-X <TITLE>ACE Tutorial 008</TITLE>
-</HEAD>
-<BODY TEXT="#000000" BGCOLOR="#FFFFFF" LINK="#000FFF" VLINK="#FF0F0F">
-X
-<CENTER><B><FONT SIZE=+2>ACE Tutorial 008</FONT></B></CENTER>
-X
-<CENTER><B><FONT SIZE=+2>Sending and receiving datagrams</FONT></B></CENTER>
-X
-X
-<P>
-<HR WIDTH="100%">
-X
-SHAR_EOF
- $shar_touch -am 0121153899 'hdr' &&
- chmod 0664 'hdr' ||
- $echo 'restore of' 'hdr' 'failed'
- if ( md5sum --help 2>&1 | grep 'sage: md5sum \[' ) >/dev/null 2>&1 \
- && ( md5sum --version 2>&1 | grep -v 'textutils 1.12' ) >/dev/null; then
- md5sum -c << SHAR_EOF >/dev/null 2>&1 \
- || $echo 'hdr:' 'MD5 check failed'
-e74ecd3335da844c263f961a8ba5f867 hdr
-SHAR_EOF
- else
- shar_count="`LC_ALL= LC_CTYPE= LANG= wc -c < 'hdr'`"
- test 515 -eq "$shar_count" ||
- $echo 'hdr:' 'original size' '515,' 'current size' "$shar_count!"
- fi
-fi
-# ============= bodies ==============
-if test -f 'bodies' && test "$first_param" != -c; then
- $echo 'x -' SKIPPING 'bodies' '(file already exists)'
-else
- $echo 'x -' extracting 'bodies' '(text)'
- sed 's/^X//' << 'SHAR_EOF' > 'bodies' &&
-PAGE=2
-server.cpp
-directed_client.cpp
-broadcast_client.cpp
-SHAR_EOF
- $shar_touch -am 0121153799 'bodies' &&
- chmod 0664 'bodies' ||
- $echo 'restore of' 'bodies' 'failed'
- if ( md5sum --help 2>&1 | grep 'sage: md5sum \[' ) >/dev/null 2>&1 \
- && ( md5sum --version 2>&1 | grep -v 'textutils 1.12' ) >/dev/null; then
- md5sum -c << SHAR_EOF >/dev/null 2>&1 \
- || $echo 'bodies:' 'MD5 check failed'
-707d1735ca25694e2b5fddc1f6e7e124 bodies
-SHAR_EOF
- else
- shar_count="`LC_ALL= LC_CTYPE= LANG= wc -c < 'bodies'`"
- test 59 -eq "$shar_count" ||
- $echo 'bodies:' 'original size' '59,' 'current size' "$shar_count!"
- fi
-fi
-# ============= page01.pre ==============
-if test -f 'page01.pre' && test "$first_param" != -c; then
- $echo 'x -' SKIPPING 'page01.pre' '(file already exists)'
-else
- $echo 'x -' extracting 'page01.pre' '(text)'
- sed 's/^X//' << 'SHAR_EOF' > 'page01.pre' &&
-<P>In a lot of IPC&nbsp;programming, the clients know where the servers
-are.&nbsp; A mail client, for instance, has a configuration file that says
-where the mail host is.&nbsp; Your web browser has a "location" field that
-you type into to give it a destination.
-X
-<P>What if you have written a server application and then you execute it
-on several systems in your network?&nbsp; All of the instances are probably
-more or less equal to the client's point of view, so you don't want to
-"configure"&nbsp;the clients to a single server each.&nbsp; Likewise, you
-want the ability to add and remove servers at any time so you can't just
-give the clients a list to choose from.
-X
-<P>So... how do the clients know where the servers are?
-X
-<P>Let 'em ask!
-X
-<P>Datagrams are great for this.&nbsp; You can toss a datagram out onto
-the network and any servers listening at the correct port will* hear it.&nbsp;
-Like ACE_SOCK_Stream that we've seen before, you can get the peer address
-from a datagram.&nbsp; With that, the server can&nbsp; send a response
-back to the client.&nbsp; The client, in turn, can pull the peer address
-out and know exactly where the server lives.
-X
-<P>In this tutorial we'll develop three applications:&nbsp; a server listening
-for datagrams, a client that can send to a known host and a client that
-can send to the entire (sub)network.&nbsp; In the next tutorial, we'll
-expand on this to make the server a bit more prudish.
-<P>
-Kirthika's abstract:
-<UL>
-Here, we play with datagram sockets and use it for server discovery by
-the client. Datagrams are used by UDP, which is an unreliable and
-connectionless protocol. Datagrams packets are generally very small in
-size and aren't designed to be used to handle serious communication
-between the server and the client.
-<P>
-The server waits for datagrams to arrive at a fixed port.
-The client either sends to a datagram to the server at a known host,
-which is not really the case generally, as the client needs to discover
-the server and so it needs to broadcast its datagram request in its
-subnet. Then, all servers listening at that interface receive it. The
-appropriate server will then handle the request. Remember that
-no solid connection is made. On the recv() itself the server obtains the
-address of the remote client and then communicates with it.
-<P>
-Thus, we get a fair glimpse of using another means of communication via
-datagrams.
-</UL>
-<P><FONT SIZE=-1>*&nbsp;Actually, the servers <I>might</I> hear the datagram.&nbsp;
-Datagrams are rather unreliable.&nbsp; (Sort of like some operating systems
-I know.)&nbsp; Still, if the network traffic isn't too bad, they generally
-get through.&nbsp; Your clients can always send out more queries if there
-aren't any responses in a timely fashion.</FONT>
-X
-SHAR_EOF
- $shar_touch -am 0121155099 'page01.pre' &&
- chmod 0664 'page01.pre' ||
- $echo 'restore of' 'page01.pre' 'failed'
- if ( md5sum --help 2>&1 | grep 'sage: md5sum \[' ) >/dev/null 2>&1 \
- && ( md5sum --version 2>&1 | grep -v 'textutils 1.12' ) >/dev/null; then
- md5sum -c << SHAR_EOF >/dev/null 2>&1 \
- || $echo 'page01.pre:' 'MD5 check failed'
-829e35e4a7b8e8c75e38abf492033395 page01.pre
-SHAR_EOF
- else
- shar_count="`LC_ALL= LC_CTYPE= LANG= wc -c < 'page01.pre'`"
- test 2769 -eq "$shar_count" ||
- $echo 'page01.pre:' 'original size' '2769,' 'current size' "$shar_count!"
- fi
-fi
-# ============= page02.pre ==============
-if test -f 'page02.pre' && test "$first_param" != -c; then
- $echo 'x -' SKIPPING 'page02.pre' '(file already exists)'
-else
- $echo 'x -' extracting 'page02.pre' '(text)'
- sed 's/^X//' << 'SHAR_EOF' > 'page02.pre' &&
-X
-<P>The first thing we want to look at is <A HREF="server.cpp">server.cpp</A>.&nbsp;
-This is a pretty simple application that listens for datagrams at a known
-port and sends back a response.&nbsp; In order to implement a true "discovery"&nbsp;
-mechanism, the server will have to be a little bit more picky about who
-it responds to.&nbsp; We'll tackle that issue in the next tutorial though...
-X
-<P>
-<HR WIDTH="100%">
-SHAR_EOF
- $shar_touch -am 0121153899 'page02.pre' &&
- chmod 0664 'page02.pre' ||
- $echo 'restore of' 'page02.pre' 'failed'
- if ( md5sum --help 2>&1 | grep 'sage: md5sum \[' ) >/dev/null 2>&1 \
- && ( md5sum --version 2>&1 | grep -v 'textutils 1.12' ) >/dev/null; then
- md5sum -c << SHAR_EOF >/dev/null 2>&1 \
- || $echo 'page02.pre:' 'MD5 check failed'
-6b27ef52d53a13d2d9e5a5ad16e9be4d page02.pre
-SHAR_EOF
- else
- shar_count="`LC_ALL= LC_CTYPE= LANG= wc -c < 'page02.pre'`"
- test 416 -eq "$shar_count" ||
- $echo 'page02.pre:' 'original size' '416,' 'current size' "$shar_count!"
- fi
-fi
-# ============= page03.pre ==============
-if test -f 'page03.pre' && test "$first_param" != -c; then
- $echo 'x -' SKIPPING 'page03.pre' '(file already exists)'
-else
- $echo 'x -' extracting 'page03.pre' '(text)'
- sed 's/^X//' << 'SHAR_EOF' > 'page03.pre' &&
-X
-<P>In <A HREF="directed_client.cpp">directed_client.cpp</A> we create a
-client that knows how to send a datagram to a server on a known host.&nbsp;
-This is a good thing if you know where the server lives and want to have
-a conversation.&nbsp;&nbsp; The Unix <I>talk</I> utilitiy, for instance,
-could be written this way.
-X
-<P>
-<HR WIDTH="100%">
-SHAR_EOF
- $shar_touch -am 0121153899 'page03.pre' &&
- chmod 0664 'page03.pre' ||
- $echo 'restore of' 'page03.pre' 'failed'
- if ( md5sum --help 2>&1 | grep 'sage: md5sum \[' ) >/dev/null 2>&1 \
- && ( md5sum --version 2>&1 | grep -v 'textutils 1.12' ) >/dev/null; then
- md5sum -c << SHAR_EOF >/dev/null 2>&1 \
- || $echo 'page03.pre:' 'MD5 check failed'
-aa0724ca0a09f5b5e6c7e3f355646111 page03.pre
-SHAR_EOF
- else
- shar_count="`LC_ALL= LC_CTYPE= LANG= wc -c < 'page03.pre'`"
- test 345 -eq "$shar_count" ||
- $echo 'page03.pre:' 'original size' '345,' 'current size' "$shar_count!"
- fi
-fi
-# ============= page04.pre ==============
-if test -f 'page04.pre' && test "$first_param" != -c; then
- $echo 'x -' SKIPPING 'page04.pre' '(file already exists)'
-else
- $echo 'x -' extracting 'page04.pre' '(text)'
- sed 's/^X//' << 'SHAR_EOF' > 'page04.pre' &&
-In <A HREF="broadcast_client.cpp">broadcast_client.cpp</A> we
-find out how to send a single datagram to every host on our (sub)network.&nbsp;
-I have to say <I>(sub)network</I> because broadcast datagrams typically
-are not passed through routers.&nbsp; So, if your network admin has divided
-up your network into subnets, your broadcasts will likey stay on the
-subnet you're a part of.
-X
-<P>I've only commented the parts that are different from the directed_client.
-<HR WIDTH="100%">
-SHAR_EOF
- $shar_touch -am 0124144899 'page04.pre' &&
- chmod 0664 'page04.pre' ||
- $echo 'restore of' 'page04.pre' 'failed'
- if ( md5sum --help 2>&1 | grep 'sage: md5sum \[' ) >/dev/null 2>&1 \
- && ( md5sum --version 2>&1 | grep -v 'textutils 1.12' ) >/dev/null; then
- md5sum -c << SHAR_EOF >/dev/null 2>&1 \
- || $echo 'page04.pre:' 'MD5 check failed'
-8811bded669a7a7be85a4878d5076190 page04.pre
-SHAR_EOF
- else
- shar_count="`LC_ALL= LC_CTYPE= LANG= wc -c < 'page04.pre'`"
- test 481 -eq "$shar_count" ||
- $echo 'page04.pre:' 'original size' '481,' 'current size' "$shar_count!"
- fi
-fi
-# ============= page05.pre ==============
-if test -f 'page05.pre' && test "$first_param" != -c; then
- $echo 'x -' SKIPPING 'page05.pre' '(file already exists)'
-else
- $echo 'x -' extracting 'page05.pre' '(text)'
- sed 's/^X//' << 'SHAR_EOF' > 'page05.pre' &&
-<BR>That's it for this tutorial.&nbsp; In the next one we'll add some intelligence
-to the data put into the datagrams.&nbsp; By doing so, we'll be able to
-classify our clients and servers into groups.&nbsp; By combining the data
-content and the server's port we can get fairly fine-grained control over
-who talks to who.
-X
-<P>For you convenience:
-<UL>
-<LI>
-<A HREF="server.cpp">server.cpp</A></LI>
-X
-<LI>
-<A HREF="directed_client.cpp">directed_client.cpp</A></LI>
-X
-<LI>
-<A HREF="broadcast_client.cpp">broadcast_client.cpp</A></LI>
-X
-<LI>
-<A HREF="Makefile">Makefile</A></LI>
-</UL>
-SHAR_EOF
- $shar_touch -am 0121153799 'page05.pre' &&
- chmod 0664 'page05.pre' ||
- $echo 'restore of' 'page05.pre' 'failed'
- if ( md5sum --help 2>&1 | grep 'sage: md5sum \[' ) >/dev/null 2>&1 \
- && ( md5sum --version 2>&1 | grep -v 'textutils 1.12' ) >/dev/null; then
- md5sum -c << SHAR_EOF >/dev/null 2>&1 \
- || $echo 'page05.pre:' 'MD5 check failed'
-b05fdac8c7eb81813c74eb99525cf601 page05.pre
-SHAR_EOF
- else
- shar_count="`LC_ALL= LC_CTYPE= LANG= wc -c < 'page05.pre'`"
- test 578 -eq "$shar_count" ||
- $echo 'page05.pre:' 'original size' '578,' 'current size' "$shar_count!"
- fi
-fi
-# ============= page02.pst ==============
-if test -f 'page02.pst' && test "$first_param" != -c; then
- $echo 'x -' SKIPPING 'page02.pst' '(file already exists)'
-else
- $echo 'x -' extracting 'page02.pst' '(text)'
- sed 's/^X//' << 'SHAR_EOF' > 'page02.pst' &&
-<HR WIDTH="100%">
-X
-<P>And that's really all there is to it.&nbsp; Obviously there is some
-room for improvement.&nbsp; The most blatant is the somewhat small buffer
-size for receiving the datagram.&nbsp; I've never been able to get a solid
-answer on datagram sizes.&nbsp; The theoretical limit is just under 64k
-but you have to deal with fragmentation.&nbsp; Some readings indicate that
-8k is a reasonable size, others go much smaller.&nbsp; My general rule
-of thumb is to keep datagrams relatively small (eg -- under 8k or so) and
-test a lot.&nbsp; If you find that your routers are fragmenting your larger
-datagrams, back off to something smaller.&nbsp; Of course, if you must
-send 100k and can only do so 1k at a time, you'll have to worry about retransmissions
-&amp; reordering.&nbsp; At that point, you might consider going to TCP.&nbsp;
-Remember:&nbsp; datagrams are unreliable!&nbsp; Don't try to make 'em do
-something they werent' designed for!
-SHAR_EOF
- $shar_touch -am 0121153899 'page02.pst' &&
- chmod 0664 'page02.pst' ||
- $echo 'restore of' 'page02.pst' 'failed'
- if ( md5sum --help 2>&1 | grep 'sage: md5sum \[' ) >/dev/null 2>&1 \
- && ( md5sum --version 2>&1 | grep -v 'textutils 1.12' ) >/dev/null; then
- md5sum -c << SHAR_EOF >/dev/null 2>&1 \
- || $echo 'page02.pst:' 'MD5 check failed'
-3cb7da5f75a40616f6cc498a731f4a16 page02.pst
-SHAR_EOF
- else
- shar_count="`LC_ALL= LC_CTYPE= LANG= wc -c < 'page02.pst'`"
- test 952 -eq "$shar_count" ||
- $echo 'page02.pst:' 'original size' '952,' 'current size' "$shar_count!"
- fi
-fi
-# ============= page03.pst ==============
-if test -f 'page03.pst' && test "$first_param" != -c; then
- $echo 'x -' SKIPPING 'page03.pst' '(file already exists)'
-else
- $echo 'x -' extracting 'page03.pst' '(text)'
- sed 's/^X//' << 'SHAR_EOF' > 'page03.pst' &&
-<HR WIDTH="100%">
-X
-<P>That's all neat and good but the point of what we're doing here is not
-to talk to a server we know about but to discover servers we don't know
-about.&nbsp; Now, you could send a directed datagram to every possible
-host address on your network but that's not a very nice thing to do.&nbsp;
-On the next page, we'll find out the right approach...
-X
-SHAR_EOF
- $shar_touch -am 0121153899 'page03.pst' &&
- chmod 0664 'page03.pst' ||
- $echo 'restore of' 'page03.pst' 'failed'
- if ( md5sum --help 2>&1 | grep 'sage: md5sum \[' ) >/dev/null 2>&1 \
- && ( md5sum --version 2>&1 | grep -v 'textutils 1.12' ) >/dev/null; then
- md5sum -c << SHAR_EOF >/dev/null 2>&1 \
- || $echo 'page03.pst:' 'MD5 check failed'
-0fcbc10be47175a0d42590fb4adab43b page03.pst
-SHAR_EOF
- else
- shar_count="`LC_ALL= LC_CTYPE= LANG= wc -c < 'page03.pst'`"
- test 367 -eq "$shar_count" ||
- $echo 'page03.pst:' 'original size' '367,' 'current size' "$shar_count!"
- fi
-fi
-# ============= page04.pst ==============
-if test -f 'page04.pst' && test "$first_param" != -c; then
- $echo 'x -' SKIPPING 'page04.pst' '(file already exists)'
-else
- $echo 'x -' extracting 'page04.pst' '(text)'
- sed 's/^X//' << 'SHAR_EOF' > 'page04.pst' &&
-<HR WIDTH="100%">
-X
-<P>&nbsp;About that subnet thing:
-<BLOCKQUOTE>If you run this client on a host that has multiple network
-interfaces, the broadcast will go to all of those (sub)networks.&nbsp;
-What do you do, though, if you need to get past a router?&nbsp; My advice
-is to write a server that will run on hosts on both sides of your router.&nbsp;
-When a server on one side of the router receives a broadcast, it would
-send a directed datagram to it's counterpart on the other side of the router.&nbsp;
-The counterpart would then re-broadcast the original datagram on that sub-net.&nbsp;
-Cheap, simple and effective.</BLOCKQUOTE>
-One final word of warning:
-<BLOCKQUOTE>When creating your broadcast datagrams you may see something
-like this:&nbsp; <I>ACE_SOCK_Dgram_Bcast::mk_broadcast: Broadcast is not
-enable for this interface.: Unknown error</I>.&nbsp; There are some interfaces
-(ppp, slip) that don't support broadcast datagrams.&nbsp; That's what you're
-seeing here.</BLOCKQUOTE>
-Ok, one more warning:
-<blockquote>If you happen to have multiple servers running on your
-network when you invoke this client, the response could come from any
-one of them.
-</blockquote>
-X
-SHAR_EOF
- $shar_touch -am 0126194899 'page04.pst' &&
- chmod 0664 'page04.pst' ||
- $echo 'restore of' 'page04.pst' 'failed'
- if ( md5sum --help 2>&1 | grep 'sage: md5sum \[' ) >/dev/null 2>&1 \
- && ( md5sum --version 2>&1 | grep -v 'textutils 1.12' ) >/dev/null; then
- md5sum -c << SHAR_EOF >/dev/null 2>&1 \
- || $echo 'page04.pst:' 'MD5 check failed'
-2e01fc6b6638dfa77ed629c0e3e77e21 page04.pst
-SHAR_EOF
- else
- shar_count="`LC_ALL= LC_CTYPE= LANG= wc -c < 'page04.pst'`"
- test 1173 -eq "$shar_count" ||
- $echo 'page04.pst:' 'original size' '1173,' 'current size' "$shar_count!"
- fi
-fi
-rm -fr _sh30434
-exit 0