dumbnet — dumb networking library test program

       Dug Song ⟨dugsong@monkey.org⟩
       Oliver Falk ⟨oliver@linux-kernel.at⟩

Debian                                          October 17, 2001                                         DNET(8)

       The library was originally named dnet but was renamed to dumbnet  due  to  a  conflict  with  the  DECnet
       library.  This  decision  affects  not  only the filename of the shared library, but also the header file
       names and the library's SONAME tag, which means that software built on a non-Debian-derived  distribution
       will  not run with this library and recompiling the software will only work if some adjustments to header
       include directives and compiler/linker flags are made.

dumbnet  is  a  simple  test  program  for the dumbnet(3) library. It can be used to compose and transmit
       network datagrams as a Unix-style filter (e.g. reading from or writing to files and pipes) or modify  the
       local  system  network  configuration (including the ARP cache, firewall ruleset, network interfaces, and
       routing table).

   Payloadgenerationcommandsaddraddress [...]
            Convert the address (specified  as  a  hostname,  IP  address,  or  MAC  address)  into  its  binary
            representation on standard output.

       hexstring [...]
            Convert  the  C-style  escaped  string  (shellcode,  for instance) into its binary representation on
            standard output.

       randlen
            Write len random bytes to standard output.

   Packetencapsulationcommandseth [typetype] [srcmac] [dstmac]
            Prepend the data read from standard input with an Ethernet header on standard output.  The  Ethernet
            type may be specified as ‘arp’, ‘ip’, or as a hex, octal, or decimal number.

       arp [opop] [shamac] [spahost] [thamac] [tpahost]
            Prepend  the  data read from standard input with an ARP header on standard output. The ARP op may be
            specified as ‘req’, ‘rep’, ‘revreq’, ‘revrep’, or as a hex, octal, or decimal number.

       ip [tosnum] [idnum] [offoffset] [ttlnum] [protoprotocol] [srchost] [dstdst]
            Prepend the data read from standard input with an IP header on standard  output.  The  fragmentation
            offset  may  be  specified  as  a  decimal number (optionally concatenated with ‘+’ to indicate more
            fragments) or as a hex number. The protocol may be specified by name, or as a hex, octal, or decimal
            number.

       icmp [typenum] [codenum]
            Prepend the data read from standard input with an ICMP header on standard output.

       tcp [sportport] [dportport] [flagsflags] [seqnum] [acknum] [winnum] [urpnum]
            Prepend the data read from standard input with a TCP header  on  standard  output.  A  port  may  be
            specified  by  name  or  hex,  octal,  or  decimal  number.  The  TCP flags may be specified as some
            combination of the characters in the set ‘SAFRPU’ or as a hex number.

       udp [sportport] [dportport]
            Prepend the data read from standard input with a UDP header  on  standard  output.  A  port  may  be
            specified by name or hex, octal, or decimal number.

   Packettransmissioncommandssend [device]
            Read  a  packet  from  standard  input  and send it over the network. If no device is specified, the
            packet is assumed to be an IP datagram and routed to  its  destination.  Otherwise,  the  packet  is
            assumed to be an Ethernet frame and is transmitted on the specified interface.

   Kernelinterfacecommandsarpshow
            Display the kernel ARP cache.

       arpgethost
            Display the kernel ARP entry for host.

       arpaddhostmac
            Add an ARP entry mapping the mac address for host.

       arpdeletehost
            Delete the ARP entry for host.

       fwshow
            Display the kernel firewall ruleset.

       fwadd|deleteactiondirectiondeviceprotocolsrc[:port[-max]] dst[:port[-max]] [type[/code]]
            Add  a  rule to or delete a rule from the active firewall ruleset. The action must be either ‘allow’
            or ‘block’.  The direction must be either ‘in’ or ‘out’.  The device may specify an interface  name,
            or ‘any’.  The protocol may be specified by name, or as a decimal number. For TCP and UDP protocols,
            a  port  (or  range,  if specified with a max value) may be specified in decimal and appended to the
            source and/or destination address. For ICMP, a type (and optional code) may be specified in decimal.

       intfshow
            Display the configuration of all network interfaces.

       intfgetdevice
            Display the configuration for the interface specified by device.

       intfsetdevice [aliashost] [dsthost] [inethost] [linkmac] [up|down] [arp|noarp]
            Configure the interface specified by device.

       routeshow
            Display the kernel routing table.

       routegetdst
            Display the route for the destination dst, specified as a hostname, IP address, or network prefix in
            CIDR notation.

       routeadddstgw
            Add a route for the destination dst through the gateway gw.

       routedeletedst
            Delete the route for the destination dst.

       Send a UDP datagram containing random shellcode:

             dumbnet hex "\xeb\x1f\x5e\x89\x76\x08\x31\xc0\x88\x46\x07\x89" \
             "\x46\x0c\xb0\x0b\x89\xf3\x8d\x4e\x08\x8d\x56\x0c\xcd\x80" \
             "\x31\xdb\x89\xd8\x40\xcd\x80\xe8\xdc\xff\xff\xff/bin/sh" | \
             dumbnet udp sport 555 dport 666 | \
             dumbnet ip proto udp src 1.2.3.4 dst 5.6.7.8 | dumbnet send

       Save an ARP request in a file and send it twice:

             dumbnet arp op req sha 0:d:e:a:d:0 spa 10.0.0.3 tpa 10.0.0.4 | \
             dumbnet eth type arp src 0:d:e:a:d:0 dst ff:ff:ff:ff:ff:ff > arp.pkt
             dumbnet send fxp0 < arp.pkt
             dumbnet send fxp0 < arp.pkt

       Send a fragmented ping packet:

             # Create ping packet with IP header, to set ICMP checksum
             echo "monkey monkey monkey monkey" | dumbnet icmp type 8 code 0 | \
             dumbnet ip proto icmp src 1.2.3.4 dst 5.6.7.8 > ping.pkt

             # Chop off IP header
             dd if=ping.pkt of=ping.data bs=20 skip=1

             # Fragment IP payload
             split -b 24 ping.data p.

             # Send fragments
             dumbnet ip id 1 off 0+ proto icmp src 1.2.3.4 dst 5.6.7.8 < p.aa | \
             dumbnet send
             dumbnet ip id 1 off 24 proto icmp src 1.2.3.4 dst 5.6.7.8 < p.ab | \
             dumbnet send

       dumbnet — dumb networking library test program

dumbnet(3)

dumbnetcommandargs [...]