combine.shar

这是广泛使用的通信开源项目,对于大容量,高并发的通讯要求完全能够胜任,他广泛可用于网络游戏医学图像网关的高qos要求.更详细的内容可阅读相应的材料

  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 03191459100 '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 03191459100 '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 03191459100 '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 03191459100 '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 03191459100 '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 03191459100 '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 _sh32494
exit 0