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1 | #!/usr/bin/perl |
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2 | # Encrypting VPN tunnel for use with userv-ipif. |
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3 | # |
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4 | # This comment is reference documentation. See ipif/INSTALL for the |
5 | # installation instructions and setup tutorial. |
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6 | # |
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7 | # usage: |
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8 | # To make a tunnel between two machines `alice' and `bob', |
9 | # on `alice', the active endpoint, run: |
10 | # |
11 | # udptunnel |
12 | # [ -l[<alice-command/arg>] ... . |
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13 | # | -e <encryption-mech>[/<encryption-parameter>...] |
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14 | # | -m (`masquerade support': bob gets `Wait' instead of our addr/port) |
15 | # | -d (`dump keys': when no peer, spew keys rather than reading them; |
16 | # we always send keys to our peer if there is one) |
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17 | # | -Dcrypto (debug crypto - use with care, prints keys, packets &c on screen!) |
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18 | # | -f<path-to-udptunnel-forwarder> |
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19 | # ... |
20 | # ] |
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21 | # <alice-phys-addr>,<alice-phys-port> |
22 | # <bob-phys-addr>,<bob-phys-port> |
23 | # <alice-virt-addr>,<bob-virt-addr>,<mtu>,<proto> |
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24 | # <keepalive>,<timeout>[,<reannounce>] |
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25 | # <alice-priv-nets> <bob-priv-nets> |
26 | # [ <bob-command> [<bob-args> ...] ] |
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27 | # |
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28 | # This will run udptunnel-forwarder on alice, and use <bob-command> |
29 | # (usually an ssh invocation) to run udptunnel appropriately on bob. |
30 | # Key material will be generated by alice and fed to udptunnel on bob |
31 | # via <bob-command>'s stdin, and the physical address and port on bob |
32 | # will be (if so configured) returned via <bob-command>'s stdout. |
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33 | # |
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34 | # The tunnel will stay up until one of the subprocesses involved dies, |
35 | # or the keepalive timeout expires. If you want the tunnel to remain |
36 | # up permanently, you must arrange to invoke it repeatedly (eg, from |
37 | # inittab). See INSTALL. |
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38 | # |
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39 | # <proto> may be slip or cslip |
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40 | # |
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41 | # <mtu> will be the MTU of the tunnel interfaces; it is best if this |
42 | # is enough smaller than the path MTU between the physical interfaces |
43 | # that the encapsulated packets will fit without fragmentation. |
44 | # |
45 | # Any <..-addr> supplied to udptunnel may also be hostname; these will |
46 | # all be looked up on alice and IP addresses passed to bob. |
47 | # |
48 | # The `local' physical address and ports (ie, alice's own details), |
49 | # may have these special values: |
50 | # `Any' choose one ourselves and do not print it (the port chosen |
51 | # will be supplied to bob) |
52 | # `Print' choose one ourselves and print both port and addr |
53 | # (this is not usually useful specified directly; it's |
54 | # used by udptunnel when it invokes itself on bob via |
55 | # <bob-command>, to have its other self print the |
56 | # relevant value. |
57 | # |
58 | # The `remote' physical address and port (ie, on alice, bob's details), |
59 | # may also have the special values: |
60 | # `Command' wait for <bob-command> to tell us the values (this is |
61 | # usually the right choice on alice for at least the |
62 | # port). <bob-command> must be specified (ie, this |
63 | # only makes sense on alice). |
64 | # `Wait' alice will wait to receive a packet from bob and use |
65 | # whatever address and port it came from |
66 | # |
67 | # These special values are case-sensitive. When alice runs udptunnel |
68 | # on bob they are automatically translated to appropriate other values |
69 | # in the arguments to bob's udptunnel. |
70 | # |
71 | # If <bob-command> is specified it should run udptunnel at the |
72 | # bob end; it will be invoked as |
73 | # <bob-command> [ <bob-args> ... ] |
74 | # [ <-e arguments passed along> ] |
75 | # <bob-phys-addr'>,<bob-phys-port'> |
76 | # <alice-phys-addr'>,<alice-phys-port'> |
77 | # <bob-virt-addr>,<alice-virt-addr>,<mtu>,<proto> |
78 | # <keepalive>,<timeout>[,<reannounce>] |
79 | # <bob-priv-nets> <alice-priv-nets> |
80 | # |
81 | # If it was given Print for <bob-phys-foo'>, udptunnel's first stdout |
82 | # output will be the real <bob-phys-addr>,<bob-phys-port> pair. It |
83 | # may then produce more stdout which, if any, will be forwarded to the |
84 | # local end's stdout as debugging info. |
85 | # |
86 | # After this, if any encryption was specified, the encryption key |
87 | # material will be fed into its stdin. See the documentation in the |
88 | # mech-*.c files for details of the parameters. udptunnel on alice |
89 | # will arrange to feed the keys fd of udptunnel-forwarder into the |
90 | # stdin of the udptunnel on bob. |
91 | # |
92 | # <bob-phys-foo'> is as follows: |
93 | # <bob-phys-foo> <bob-phys-foo'> |
94 | # actual addr/port that addr/port |
95 | # `Command' `Print' |
96 | # `Wait' `Any' |
97 | # |
98 | # <alice-phys-foo'> is as follows: |
99 | # <alice-phys-foo> <alice-phys-foo'> <alice-phys-foo'> |
100 | # (-m not specified) (-m specified) |
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101 | # actual addr/port that addr/port `Wait' |
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102 | # `Print' the chosen address `Wait' |
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103 | # `Any' `Wait' for addr, `Wait' |
104 | # chosen port for port |
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105 | # |
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106 | # In each case udptunnel will run userv ipif locally, as |
107 | # userv root ipif <local-virt-addr>,<remote-virt-addr>,<mtu>,<proto> |
108 | # <remote-priv-nets> |
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109 | # or, if -l was given, userv root ipif is replaced with the argument(s) |
110 | # following -l option(s) until `.'. |
111 | # |
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112 | # udptunnel will also run udptunnel-forwarder with appropriate options. |
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113 | # |
114 | # recommended encryption parameters are: |
115 | # -e nonce (prepend 32 bit counter) |
116 | # -e timestamp/<max-skew>/<max-age> (prepend 32 bit time_t, and check on receipt) |
117 | # -e pkcs5/8 (pad as per PKCS#5 to 8-byte boundary) |
118 | # -e blowfish-cbcmac/128 (prepend CBC MAC with random IV and 128 bit key) |
119 | # -e blowfish-cbc/128 (encrypt with CBC, random IV and 128 bit key) |
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120 | # where <max-skew> is perhaps 10 and <max-age> perhaps 30. If your |
121 | # clocks are not sufficiently well synchronised, you could replace |
122 | # `-e nonce -e timestamp/...' with just `-e sequence'. Do not just |
123 | # remove `-e timestamp/...'. |
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124 | |
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125 | # Copyright (C) 1999-2000 Ian Jackson |
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126 | # |
127 | # This is free software; you can redistribute it and/or modify it |
128 | # under the terms of the GNU General Public License as published by |
129 | # the Free Software Foundation; either version 2 of the License, or |
130 | # (at your option) any later version. |
131 | # |
132 | # This program is distributed in the hope that it will be useful, but |
133 | # WITHOUT ANY WARRANTY; without even the implied warranty of |
134 | # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
135 | # General Public License for more details. |
136 | # |
137 | # You should have received a copy of the GNU General Public License |
138 | # along with userv-utils; if not, write to the Free Software |
139 | # Foundation, 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. |
140 | # |
141 | # $Id$ |
142 | |
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143 | use Socket; |
144 | use POSIX; |
145 | use Fcntl; |
146 | |
147 | $progname= $0; $progname =~ s,.*/,,; |
148 | $|=1; |
149 | |
150 | chomp($hostname= `uname -n`); |
151 | $? and die "$progname: cannot get hostname (uname failed with code $?)\n"; |
152 | |
153 | sub quit ($) { die "$progname - $hostname: fatal error: $_[0]\n"; } |
154 | sub debug ($) { print "$progname - $hostname: debug: $_[0]\n"; } |
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155 | sub fail ($) { quit("unexpected system call failure: $_[0]: $!"); } |
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156 | sub warning ($) { warn "$progname - $hostname: $_[0]\n"; } |
157 | |
158 | sub eat_addr_port ($) { |
159 | my ($x) = @_; |
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160 | @ARGV or quit("<addr>,<port> missing"); |
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161 | $_= shift(@ARGV); |
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162 | (m/^$x,/i && m/^[a-z]/ || m/,$x$/i && m/,[a-z]/) |
163 | and warning("$_: use Mixed Case for special values"); |
164 | m/^([0-9a-z][0-9a-z-+.]+|$x)\,(\d+|$x)$/ |
165 | or quit("$_: <host/addr>,<port> bad syntax". |
166 | (m/[A-Z]/ ? ' (use lowercase for hostnames)' : '')); |
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167 | return ($1,$2); |
168 | } |
169 | sub conv_host_addr ($) { |
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170 | my ($s,$r,@h) = @_; |
171 | return INADDR_ANY() if $s =~ m/^[A-Z][a-z]/; |
172 | return $r if defined($r= inet_aton($s)); |
173 | @h= gethostbyname($s) or quit("$s: cannot get address"); |
174 | $h[2] eq &AF_INET or quit("$s: address is not IPv4"); |
175 | @h < 5 or quit("$s: name maps to no addresses"); |
176 | $r= $h[4]; |
177 | @h == 5 or warning("$s: name has several addresses, using ".inet_ntoa($r)); |
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178 | return $r; |
179 | } |
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180 | sub conv_port_number ($) { |
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181 | my ($s,$r) = @_; |
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182 | return 0 if $s =~ m/^[A-Z][a-z]/; |
183 | $r= $s+0; |
184 | $r>0 && $r<65536 or quit("$s: port out of range"); |
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185 | return $r; |
186 | } |
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187 | sub show_addr ($) { |
188 | my ($s,@s) = @_; |
189 | @s= unpack_sockaddr_in($s); |
190 | return inet_ntoa($s[1]); |
191 | } |
192 | sub show_port ($) { |
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193 | my ($s,@s) = @_; |
194 | @s= unpack_sockaddr_in($s); |
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195 | return $s[0]; |
196 | } |
197 | sub show_addr_port ($) { |
198 | my ($s) = @_; |
199 | return show_addr($s).','.show_port($s); |
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200 | } |
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201 | sub arg_value ($$) { |
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202 | my ($val,$opt) = @_; |
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203 | $_= '-'; |
204 | return $val if length $val; |
205 | @ARGV or quit("$opt needs value"); |
206 | return shift @ARGV; |
207 | } |
208 | |
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209 | @lcmd= (); |
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210 | @encryption= (); |
211 | $masq= 0; |
212 | $dump= 0; |
213 | $fcmd= 'udptunnel-forwarder'; |
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214 | $xfwdopts= ''; |
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215 | |
216 | while ($ARGV[0] =~ m/^-/) { |
217 | $_= shift @ARGV; |
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218 | last if m/^--?$/; |
219 | while (!m/^-$/) { |
220 | if (s/^-l//) { |
221 | push @lcmd,$_ if length; |
222 | while (@ARGV && ($_= shift @ARGV) ne '.') { push @lcmd, $_; } |
223 | $_= '-' |
224 | } elsif (s/^-f//) { |
225 | $fcmd= arg_value($_,'-f'); |
226 | } elsif (s/^-e//) { |
227 | $encrarg= arg_value($_,'-e'); |
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228 | push @remoteopts, "-e$encrarg"; |
229 | @thisencryption= split m#/#, $encrarg; |
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230 | $thisencryption[0] =~ s/^/\|/; |
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231 | push @encryption, @thisencryption; |
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232 | } elsif (s/^-m/-/) { |
233 | $masq= 1; |
234 | } elsif (s/^-d/-/) { |
235 | $dump= 1; |
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236 | } elsif (s/^-Dcrypto$/-/) { |
237 | $xfwdopts.= 'K'; |
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238 | push @remoteopts, '-Dcrypto'; |
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239 | } else { |
240 | quit("unknown option \`$_'"); |
241 | } |
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242 | } |
243 | } |
244 | |
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245 | # Variables \$[lr]a?p?(|s|d|r) |
246 | # Local/Remote Address&/Port |
247 | # actualvalue/Specified/Displaypassdown/fromRemote/passtoForwarder |
248 | # |
249 | ($las,$lps)= eat_addr_port('Print|Any'); |
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250 | $la= conv_host_addr($las); |
251 | $lp= conv_port_number($lps); |
252 | $ls= pack_sockaddr_in $lp,$la; |
253 | |
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254 | ($ras,$rps)= eat_addr_port('Wait|Command'); |
255 | $ra= conv_host_addr($ras); |
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256 | $rp= conv_port_number($rps); |
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257 | $rs= pack_sockaddr_in $rp,$ra; |
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258 | |
259 | $_= shift @ARGV; |
260 | m/^([.0-9]+),([.0-9]+),(\d+),(slip|cslip)$/ |
261 | or quit("lvaddr,rvaddr,mtu,proto missing or bad syntax or proto not [c]slip"); |
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262 | ($lva,$rva,$mtu,$proto) = ($1,$2,$3,$4); |
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263 | |
264 | $_= shift @ARGV; |
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265 | if (m/^(\d+),(\d+)$/) { |
266 | ($keepalive,$timeout,$reannounce)= ($1+0,$2+0,0); |
267 | $ka_to_ra= "$keepalive,$timeout"; |
268 | } elsif (m/^(\d+),(\d+),(\d+)$/) { |
269 | ($keepalive,$timeout,$reannounce)= ($1+0,$2+0,$3); |
270 | "$keepalive,$timeout", |
271 | $ka_to_ra= "$keepalive,$timeout,$reannounce"; |
272 | } else { |
273 | quit("keepalive,timeout missing or bad syntax"); |
274 | } |
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275 | $keepalive && ($timeout > $keepalive*2) or quit("timeout must be < 2*keepalive") |
276 | if $timeout; |
277 | |
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278 | # Variables \$[lr]exn |
279 | # Local/Remote Extra Nets |
280 | $lexn= shift @ARGV; |
281 | $rexn= shift @ARGV; |
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282 | |
283 | defined($udp= getprotobyname('udp')) or fail("getprotobyname udp"); |
284 | |
285 | socket(L,PF_INET,SOCK_DGRAM,$udp) or fail("socket"); |
286 | bind(L,$ls) or quit("bind failed: $!"); |
287 | defined($ls= getsockname(L)) or fail("getsockname"); |
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288 | $lad= show_addr($ls); |
289 | $lpd= show_port($ls); |
290 | $lapd= "$lad,$lpd"; |
291 | |
292 | print "$lapd\n" or fail("print addr/port") if ($las eq 'Print' || $lps eq 'Print'); |
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293 | |
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294 | $rapcmd= ($ras eq 'Command' || $rps eq 'Command'); |
295 | quit("need remote-command if Command for remote addr/port") if $rapcmd && !@ARGV; |
296 | |
297 | sub xform_remote ($$) { |
298 | my ($showed,$spec) = @_; |
299 | return 'Print' if $spec eq 'Command'; |
300 | return 'Any' if $spec eq 'Wait'; |
301 | return $showed; |
302 | } |
303 | |
304 | if (@ARGV) { |
305 | warning("-d specified with remote command, ignoring") if $dump; |
306 | $dump= 1; |
307 | |
308 | $rad= xform_remote(show_addr($rs),$ras); |
309 | $rpd= xform_remote(show_port($rs),$rps); |
310 | @rcmd= (@ARGV, |
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311 | @remoteopts, |
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312 | "$rad,$rpd", |
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313 | $masq ? 'Wait,Wait' : $las eq 'Any' ? "Wait,$lpd" : $lapd, |
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314 | "$rva,$lva,$mtu,$proto", |
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315 | $ka_to_ra, |
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316 | $rexn, $lexn); |
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317 | debug("remote command @rcmd"); |
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318 | |
319 | if ($rapcmd) { |
320 | pipe(RAPREAD,RCMDREADSUB) or fail("pipe"); |
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321 | } |
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322 | pipe(RCMDWRITESUB,DUMPKEYS) or fail("pipe"); |
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323 | defined($c_rcmd= fork) or fail("fork for remote"); |
324 | if (!$c_rcmd) { |
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325 | open STDIN, "<&RCMDWRITESUB" or fail("reopen stdin for remote command"); |
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326 | open STDOUT, ">&RCMDREADSUB" or fail("reopen stdout for remote command") |
327 | if $rapcmd; |
328 | close RAPREAD if $rapcmd; |
329 | close DUMPKEYS; |
330 | close RCMDWRITESUB; |
331 | close RCMDREADSUB; |
332 | close L; |
333 | exec @rcmd; fail("failed to execute remote command $rcmd[0]"); |
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334 | } |
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335 | close RCMDWRITESUB; |
336 | |
337 | if ($rapcmd) { |
338 | close RCMDREADSUB if $rapcmd; |
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339 | $_= ''; |
340 | while (!m/\n/) { |
341 | $!=0; |
342 | defined($nread= sysread(RAPREAD,$_,1,length)) |
343 | or fail("read from remote command"); |
344 | if (!$nread) { |
345 | close DUMPKEYS; |
346 | close RAPREAD; |
347 | waitpid $c_rcmd,0 or fail("wait for remote command"); |
348 | quit($? ? "remote command failed (code $?)" : |
349 | "no details received from remote"); |
350 | } |
351 | } |
352 | chomp; |
353 | m/^([.0-9]+)\,(\d+)$/ or quit("invalid details from remote end: \`$_'"); |
354 | ($rar,$rpr) = ($1,$2); |
355 | $ra= conv_host_addr($rar); |
356 | $rp= conv_port_number($rpr); |
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357 | |
358 | defined($c_catremdebug= fork) or fail("fork for cat remote debug"); |
359 | if (!$c_catremdebug) { |
360 | open(STDIN,"<&RAPREAD") or fail("redirect remote debug"); |
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361 | close DUMPKEYS; |
362 | close L; |
363 | exec "cat"; fail("execute cat"); |
364 | } |
365 | close RAPREAD; |
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366 | } |
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367 | } elsif ($dump) { |
368 | open DUMPKEYS, ">&STDOUT" or fail("reopen stdout for key material"); |
369 | $dump= 1; |
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370 | } else { |
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371 | open DUMPKEYS, "<&STDIN" or fail("reopen stdout for key material"); |
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372 | } |
373 | |
374 | $rs= pack_sockaddr_in $rp,$ra; |
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375 | |
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376 | if ($ras eq 'Wait' || $rps eq 'Wait') { |
377 | @rapf= (''); |
378 | $rapd= ('Wait,Wait'); |
379 | } else { |
380 | @rapf= (show_addr($rs), show_port($rs)); |
381 | $rapd= show_addr_port($rs); |
382 | } |
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383 | @lcmd= qw(userv root ipif) unless @lcmd; |
384 | |
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385 | debug("using remote $rapd local $lapd"); |
386 | push @lcmd, ("$lva,$rva,$mtu,$proto",$lexn); |
387 | debug("local command @lcmd."); |
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388 | |
389 | pipe(UR,UW) or fail("up pipe"); |
390 | pipe(DR,DW) or fail("down pipe"); |
391 | |
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392 | defined($c_lcmd= fork) or fail("fork for local command"); |
393 | if (!$c_lcmd) { |
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394 | close UR; close DW; |
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395 | open(STDIN,"<&DR") or fail("reopen stdin for packets"); |
396 | open(STDOUT,">&UW") or fail("reopen stdout for packets"); |
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397 | exec @lcmd; |
398 | quit("cannot execute $lcmd[0]: $!"); |
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399 | } |
400 | close UW; |
401 | close DR; |
402 | |
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403 | $xfwdopts.= 'w' if $dump; |
404 | |
405 | @fcmd= ($fcmd, $xfwdopts, |
406 | fileno(L), fileno(DW), fileno(UR), fileno(DUMPKEYS), |
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407 | $mtu, $keepalive, $timeout, $reannounce, |
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408 | @rapf, |
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409 | @encryption); |
410 | debug("forwarding command @fcmd."); |
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411 | |
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412 | defined($c_fwd= fork) or fail("fork for udptunnel-forwarder"); |
413 | if (!$c_fwd) { |
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414 | foreach $fd (qw(L DW UR DUMPKEYS)) { |
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415 | fcntl($fd, F_SETFD, 0) or fail("set no-close-on-exec $fd"); |
416 | } |
417 | exec @fcmd; fail("cannot execute $fcmd[0]"); |
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418 | } |
419 | |
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420 | close L; |
421 | close DUMPKEYS; |
422 | close UR; |
423 | close DW; |
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424 | |
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425 | %procs= ($c_fwd, 'forwarder', |
426 | $c_lcmd, 'local command'); |
427 | $procs{$c_rcmd}= 'remote command' if $c_rcmd; |
428 | $procs{$c_catremdebug}= 'debug cat' if $c_catremdebug; |
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429 | |
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430 | $estatus= 0; |
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431 | |
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432 | while (keys %procs) { |
433 | ($c= wait) >0 or |
434 | fail("wait failed (expecting ". join('; ',keys %procs). ")"); |
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435 | $status= $?; |
436 | warning("unexpected child reaped: pid $c, code $status"), next |
9d4e63db |
437 | unless exists $procs{$c}; |
438 | $str= $procs{$c}; |
439 | delete $procs{$c}; |
0f4b558c |
440 | $status ? warning("subprocess $str failed with code $status") |
9d4e63db |
441 | : debug("subprocess $str finished"); |
442 | if ($c==$c_lcmd || $c==$c_fwd || $c==$c_rcmd) { |
443 | kill 15, grep (exists $procs{$_}, $c_fwd, $c_rcmd); |
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444 | } |
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445 | $estatus=1 unless $c == $c_catremdebug; |
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446 | } |
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447 | |
448 | debug("all processes terminated, exiting with status $estatus"); |
449 | |
450 | exit $estatus; |