NAME¶
dumbnet
—
dumb networking library test program
SYNOPSIS¶
dumbnet
command
args
[... ] |
|
DESCRIPTION¶
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).
Payload generation commands¶
addr
address [...
]
- Convert the address (specified as a
hostname, IP address, or MAC address) into its binary representation on
standard output.
hex
string [...
]
- Convert the C-style escaped string
(shellcode, for instance) into its binary representation on standard
output.
rand
len
- Write len random bytes to standard
output.
Packet encapsulation commands¶
eth
[type
type
]
[src
mac
]
[dst
mac
]
- 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
[op
op
]
[sha
mac
]
[spa
host
]
[tha
mac
]
[tpa
host
]
- 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
[tos
num
]
[id
num
]
[off
offset
]
[ttl
num
]
[proto
protocol
]
[src
host
]
[dst
dst
]
- 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
[type
num
]
[code
num
]
- Prepend the data read from standard input with an ICMP header on standard
output.
tcp
[sport
port
]
[dport
port
]
[flags
flags
]
[seq
num
]
[ack
num
]
[win
num
]
[urp
num
]
- 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
[sport
port
]
[dport
port
]
- 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.
Packet transmission commands¶
send
[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.
Kernel interface commands¶
arp show
- Display the kernel ARP cache.
arp get
host
- Display the kernel ARP entry for
host.
arp add
host
mac
- Add an ARP entry mapping the mac address
for host.
arp delete
host
- Delete the ARP entry for host.
fw show
- Display the kernel firewall ruleset.
fw
add
|delete
action
direction
device
protocol
src[:port[-max]
]
dst[:port[-max]
]
[]
- 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.
intf show
- Display the configuration of all network interfaces.
intf get
device
- Display the configuration for the interface specified by
device.
intf set
device
[alias
host
]
[dst
host
]
[inet
host
]
[link
mac
]
[up
|down
]
[arp
|noarp
]
- Configure the interface specified by
device.
route show
- Display the kernel routing table.
route get
dst
- Display the route for the destination
dst, specified as a hostname, IP address,
or network prefix in CIDR notation.
route add
dst
gw
- Add a route for the destination dst
through the gateway gw.
route delete
dst
- Delete the route for the destination
dst.
EXAMPLES¶
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
COMPATIBILITY¶
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.
SEE ALSO¶
dumbnet(3)
AUTHORS¶
Dug Song ⟨dugsong@monkey.org⟩