2 # Simple tunnel for userv-ipif tunnels.
6 # <public-local-host/addr>,<public-local-port>
7 # <public-remote-host/addr>,<public-remote-port>
8 # <private-local-addr>,<private-remote-addr>,<mtu>,<proto>
9 # <keepalive>,<timeout>
10 # <extra-local-nets> <extra-remote-nets>
11 # [ <remote-command> [<remote-args> ...] ]
13 # <local-public-port> may be number or `print' or `silent'
15 # <remote-public-port> may number or `command', in which case
16 # <remote-command> must be specified and should run udptunnel at the
17 # remote end; it will be invoked as
18 # <remote-command> <public-remote-host/addr>,print
19 # <public-local-addr>,<public-local-port>
20 # <private-remote-addr>,<private-local-addr>,<mtu>,<proto>
23 # udptunnel will userv ipif locally, as
24 # userv ipif <private-local-addr>,<private-remote-addr>,<mtu>,<proto>
31 $progname= $0; $progname =~ s,.*/,,;
34 chomp($hostname= `uname -n`);
35 $? and die "$progname: cannot get hostname (uname failed with code $?)\n";
37 sub quit ($) { die "$progname - $hostname: fatal error: $_[0]\n"; }
38 sub debug ($) { print "$progname - $hostname: debug: $_[0]\n"; }
39 sub fail ($) { quit("unexpected system call failure: $_[0]: $!\n"); }
40 sub warning ($) { warn "$progname - $hostname: $_[0]\n"; }
42 sub eat_addr_port ($) {
44 @ARGV or quit("<host/addr>,<port> missing");
46 $_ =~ m/^([^,]+)\,(\d+|$x)$/ or quit("$_: <host/addr>,<port> bad syntax");
49 sub conv_host_addr ($) {
51 defined($r= inet_aton($s)) or quit("$s: cannot convert to address");
54 sub conv_port_addr ($) {
58 $r>0 && $r<65536 or quit("$s: port out of range");
64 sub show_addr_port ($) {
66 @s= unpack_sockaddr_in($s);
67 return inet_ntoa($s[1]).','.$s[0];
70 ($las,$lps)= eat_addr_port('print|silent');
71 $la= conv_host_addr($las);
72 $lp= conv_port_number($lps);
73 $ls= pack_sockaddr_in $lp,$la;
75 ($ras,$rps)= eat_addr_port('command');
76 $rp= conv_port_number($rps);
77 $ra= $rps eq 'command' ? '' : conv_host_addr($ras);
80 m/^([.0-9]+),([.0-9]+),(\d+),(slip|cslip)$/
81 or quit("lvaddr,rvaddr,mtu,proto missing or bad syntax or proto not [c]slip");
82 ($lva,$rva,$mtu,$proto= $1,$2;
85 m/^(\d+),(\d+)$/ or quit("timeout missing or bad syntax");
86 ($keepalive,$timeout)= $1,$2;
87 $keepalive && ($timeout > $keepalive*2) or quit("timeout must be < 2*keepalive")
95 defined($udp= getprotobyname('udp')) or fail("getprotobyname udp");
97 socket(L,PF_INET,SOCK_DGRAM,$udp) or fail("socket");
98 bind(L,$ls) or quit("bind failed: $!");
99 defined($ls= getsockname(L)) or fail("getsockname");
100 $lsp= show_addr_port($ls);
102 if ($rps eq 'command') {
104 quit("when using ,command for remote, must supply command") unless @ARGV;
105 defined($c= open C,"-|") or fail("fork for remote");
107 push @ARGV, "$ras,print", "$lsp", "$rva,$lva,$mtu,$proto", $lepn;
108 debug("remote command @ARGV");
109 exec @ARGV; die "$progname: error: failed to execute $ARGV[0]: $!\n";
114 quit($? ? "remote command failed (code $?)" : "no details received from remote");
117 m/^([.0-9]+)\,(\d+)$/ or quit("invalid details from remote end ($_)");
118 ($ras,$rps) = ($1,$2);
119 $ra= conv_host_addr($ras);
120 $rp= conv_port_addr($rps);
121 defined($c2= fork) or fail("fork for cat");
123 open STDIN,">&C" or fail("redirect remote pipe to stdin");
125 exec "cat"; fail("execute cat");
128 quit("when not using ,command for remote, must not supply command") if @ARGV;
131 $rs= pack_sockaddr_in $rp,$ra;
132 $rsp= show_addr_port($rs);
134 debug("using remote $rsp");
136 if ($lps eq 'print') { print $lsp,"\n" or quit("write port to stdout: $!"); }
138 debug("public address $lsp");
140 pipe(UR,UW) or fail("up pipe");
141 pipe(DR,DW) or fail("down pipe");
143 defined($c3= fork) or fail("fork for ipif");
146 open STDIN,"<&DR" or fail("reopen stdin for packets");
147 open STDOUT,"<&UW" or fail("reopen stdout for packets");
148 exec "userv","ipif","$lva,$rva,$mtu,$proto",$lepn;
149 quit("cannot execute userv ipif: $!");
158 vec($wantreadfds,fileno(UR))= 1;
159 vec($wantreadfds,fileno(L))= 1;
163 ($fl= fcntl($fh,F_GETFL,0)) or fail("nonblock F_GETFL");
165 fcntl($fh, F_SETFL, $fl) or fail("nonblock F_SETFL");
174 select($readfds=$wantreadfds,'','',undef);
176 if (!defined($r= sysread(UR,$upbuf,$mtu*2+3,length($upbuf)))) {
177 $! == EAGAIN || warning("tunnel endpoint read error: $!");
181 quit "tunnel endpoint closed by system";
183 while (($p= index($upbuf,"\300")) >= 0) {
184 if (defined(send L,substr($upbuf,0,$p),0,$rs)) {
186 debug($downyet ? "tunnel open" : "transmit channel open");
188 warning("transmit error: $!");
190 $upbuf= substr($upbuf+1,$p);
193 while (defined($rs_from= recv L,$downbuf,$mtu*2+3,0)) {
194 $rsp_from= show_addr_port($rs_from);
195 if ($rsp_from ne $rsp) {
196 warning("got packet from incorrect peer $rsp_from");
199 if (!defined($r= syswrite(DW,$downbuf,length $downbuf))) {
200 warning("tunnel endpoint write error: $!");
201 } else if ($r != length $downbuf) {
202 warning("tunnel endpoint wrong write length");
205 debug($upyet ? "tunnel open" : "receive channel open");
208 $! == EAGAIN || warning("receive error: $!");