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TRAFGEN(8)                   netsniff-ng toolkit                  TRAFGEN(8)

NAME         top

       trafgen - a fast, multithreaded network packet generator

SYNOPSIS         top

       trafgen [options] [packet]

DESCRIPTION         top

       trafgen is a fast, zero-copy network traffic generator for debugging,
       performance evaluation, and fuzz-testing. trafgen utilizes the
       packet(7) socket interface of Linux which postpones complete control
       over packet data and packet headers into the user space. It has a
       powerful packet configuration language, which is rather low-level and
       not limited to particular protocols.  Thus, trafgen can be used for
       many purposes. Its only limitation is that it cannot mimic full
       streams resp. sessions. However, it is very useful for various kinds
       of load testing in order to analyze and subsequently improve systems
       behaviour under DoS attack scenarios, for instance.

       trafgen is Linux specific, meaning there is no support for other
       operating systems, same as netsniff-ng(8), thus we can keep the code
       footprint quite minimal and to the point. trafgen makes use of
       packet(7) socket's TX_RING interface of the Linux kernel, which is a
       mmap(2)'ed ring buffer shared between user and kernel space.

       By default, trafgen starts as many processes as available CPUs, pins
       each of them to their respective CPU and sets up the ring buffer each
       in their own process space after having compiled a list of packets to
       transmit. Thus, this is likely the fastest one can get out of the box
       in terms of transmission performance from user space, without having
       to load unsupported or non-mainline third-party kernel modules. On
       Gigabit Ethernet, trafgen has a comparable performance to pktgen, the
       built-in Linux kernel traffic generator, except that trafgen is more
       flexible in terms of packet configuration possibilities. On
       10-Gigabit-per-second Ethernet, trafgen might be slower than pktgen
       due to the user/kernel space overhead but still has a fairly high
       performance for out of the box kernels.

       trafgen has the potential to do fuzz testing, meaning a packet
       configuration can be built with random numbers on all or certain
       packet offsets that are freshly generated each time a packet is sent
       out. With a built-in IPv4 ping, trafgen can send out an ICMP probe
       after each packet injection to the remote host in order to test if it
       is still responsive/alive. Assuming there is no answer from the
       remote host after a certain threshold of probes, the machine is
       considered dead and the last sent packet is printed together with the
       random seed that was used by trafgen. You might not really get lucky
       fuzz-testing the Linux kernel, but presumably there are buggy closed-
       source embedded systems or network driver's firmware files that are
       prone to bugs, where trafgen could help in finding them.

       trafgen's configuration language is quite powerful, also due to the
       fact, that it supports C preprocessor macros. A stddef.h is being
       shipped with trafgen for this purpose, so that well known defines
       from Linux kernel or network programming can be reused. After a
       configuration file has passed the C preprocessor stage, it is
       processed by the trafgen packet compiler. The language itself
       supports a couple of features that are useful when assembling
       packets, such as built-in runtime checksum support for IP, UDP and
       TCP. Also it has an expression evaluator where arithmetic (basic
       operations, bit operations, bit shifting, ...) on constant
       expressions is being reduced to a single constant on compile time.
       Other features are ''fill'' macros, where a packet can be filled with
       n bytes by a constant, a compile-time random number or run-time
       random number (as mentioned with fuzz testing). Also, netsniff-ng(8)
       is able to convert a pcap file into a trafgen configuration file,
       thus such a configuration can then be further tweaked for a given
       scenario.

OPTIONS         top

   -i <cfg|pcap|->, -c <cfg|->, --in <cfg|pcap|->, --conf <cfg|->
       Defines the input configuration file that can either be passed as a
       normal plain text file or via stdin (''-''). Note that currently, if
       a configuration is passed through stdin, only 1 CPU will be used.  It
       is also possible to specify PCAP file with .pcap extension via
       -i,--in option, by default packets will be sent at rate considering
       timestamp from PCAP file which might be reset via -b/-t options.

   -o <dev>, -d <dev>, --out <dev>, --dev <dev>
       Defines the outgoing networking device such as eth0, wlan0 and
       others.

   -p, --cpp
       Pass the packet configuration to the C preprocessor before reading it
       into trafgen. This allows #define and #include directives (e.g. to
       include definitions from system headers) to be used in the trafgen
       configuration file.

   -D <name>=<definition>, --define <name>=<definition>
       Add macro definition for the C preprocessor to use it within trafgen
       file. This option is used in combination with the -p,--cpp option.

   -J, --jumbo-support
       By default trafgen's ring buffer frames are of a fixed size of 2048
       bytes.  This means that if you're expecting jumbo frames or even
       super jumbo frames to pass your line, then you will need to enable
       support for that with the help of this option. However, this has the
       disadvantage of a performance regression and a bigger memory
       footprint for the ring buffer.

   -R, --rfraw
       In case the output networking device is a wireless device, it is
       possible with trafgen to turn this into monitor mode and create a
       mon<X> device that trafgen will be transmitting on instead of
       wlan<X>, for instance. This enables trafgen to inject raw 802.11
       frames.

   -s <ipv4>, --smoke-test <ipv4>
       In case this option is enabled, trafgen will perform a smoke test. In
       other words, it will probe the remote end, specified by an <ipv4>
       address, that is being ''attacked'' with trafgen network traffic, if
       it is still alive and responsive. That means, after each transmitted
       packet that has been configured, trafgen sends out ICMP echo requests
       and waits for an answer before it continues.  In case the remote end
       stays unresponsive, trafgen assumes that the machine has crashed and
       will print out the content of the last packet as a trafgen packet
       configuration and the random seed that has been used in order to
       reproduce a possible bug. This might be useful when testing
       proprietary embedded devices. It is recommended to have a direct link
       between the host running trafgen and the host being attacked by
       trafgen.

   -n <0|uint>, --num <0|uint>
       Process a number of packets and then exit. If the number of packets
       is 0, then this is equivalent to infinite packets resp. processing
       until interrupted.  Otherwise, a number given as an unsigned integer
       will limit processing.

   -r, --rand
       Randomize the packet selection of the configuration file. By default,
       if more than one packet is defined in a packet configuration, packets
       are scheduled for transmission in a round robin fashion. With this
       option, they are selected randomly instread.

   -P <uint>, --cpus <uint>
       Specify the number of processes trafgen shall fork(2) off. By default
       trafgen will start as many processes as CPUs that are online and pin
       them to each, respectively. Allowed value must be within interval
       [1,CPUs].

   -t <time>, --gap <time>
       Specify a static inter-packet timegap in seconds, milliseconds,
       microseconds, or nanoseconds: ''<num>s/ms/us/ns''. If no postfix is
       given default to microseconds. If this option is given, then instead
       of packet(7)'s TX_RING interface, trafgen will use sendto(2) I/O for
       network packets, even if the <time> argument is 0. This option is
       useful for a couple of reasons: i) comparison between sendto(2) and
       TX_RING performance, ii) low-traffic packet probing for a given
       interval, iii) ping-like debugging with specific payload patterns.
       Furthermore, the TX_RING interface does not cope with interpacket
       gaps.

   -b <rate>, --rate <rate>
       Specify the packet send rate
       <num>pps/B/kB/MB/GB/kbit/Mbit/Gbit/KiB/MiB/GiB units.  Like with the
       -t,--gap option, the packets are sent in slow mode.

   -S <size>, --ring-size <size>
       Manually define the TX_RING resp. TX_RING size in
       ''<num>KiB/MiB/GiB''. On default the size is being determined based
       on the network connectivity rate.

   -E <uint>, --seed <uint>
       Manually set the seed for pseudo random number generator (PRNG) in
       trafgen. By default, a random seed from /dev/urandom is used to feed
       glibc's PRNG. If that fails, it falls back to the unix timestamp. It
       can be useful to set the seed manually in order to be able to
       reproduce a trafgen session, e.g. after fuzz testing.

   -u <uid>, --user <uid> resp. -g <gid>, --group <gid>
       After ring setup, drop privileges to a non-root user/group
       combination.

   -H, --prio-high
       Set this process as a high priority process in order to achieve a
       higher scheduling rate resp. CPU time. This is however not the
       default setting, since it could lead to starvation of other
       processes, for example low priority kernel threads.

   -A, --no-sock-mem
       Do not change systems default socket memory setting during testrun.
       Default is to boost socket buffer memory during the test to:

          /proc/sys/net/core/rmem_default:4194304
          /proc/sys/net/core/wmem_default:4194304
          /proc/sys/net/core/rmem_max:104857600
          /proc/sys/net/core/wmem_max:104857600

   -Q, --notouch-irq
       Do not reassign the NIC's IRQ CPU affinity settings.

   -q, --qdisc-path
       Since Linux 3.14, the kernel supports a socket option
       PACKET_QDISC_BYPASS, which trafgen enables by default.  This options
       disables the qdisc bypass, and uses the normal send path through the
       kernel's qdisc (traffic control) layer, which can be usefully for
       testing the qdisc path.

   -V, --verbose
       Let trafgen be more talkative and let it print the parsed
       configuration and some ring buffer statistics.

   -e, --example
       Show a built-in packet configuration example. This might be a good
       starting point for an initial packet configuration scenario.

   -C, --no-cpu-stats
       Do not print CPU time statistics on exit.

   -v, --version
       Show version information and exit.

   -h, --help
       Show user help and exit.

SYNTAX         top

       trafgen's packet configuration syntax is fairly simple. The very
       basic things one needs to know is that a configuration file is a
       simple plain text file where packets are defined. It can contain one
       or more packets. Packets are enclosed by opening '{' and closing '}'
       braces, for example:

          { /* packet 1 content goes here ... */ }
          { /* packet 2 content goes here ... */ }

       Alternatively, packets can also be specified directly on the command
       line, using the same syntax as used in the configuration files.

       When trafgen is started using multiple CPUs (default), then each of
       those packets will be scheduled for transmission on all CPUs by
       default. However, it is possible to tell trafgen to schedule a packet
       only on a particular CPU:

          cpu(1): { /* packet 1 content goes here ... */ }
          cpu(2-3): { /* packet 2 content goes here ... */ }

       Thus, in case we have a 4 core machine with CPU0-CPU3, packet 1 will
       be scheduled only on CPU1, packet 2 on CPU2 and CPU3. When using
       trafgen with --num option, then these constraints will still be valid
       and the packet is fairly distributed among those CPUs.

       Packet content is delimited either by a comma or whitespace, or both:

          { 0xca, 0xfe, 0xba 0xbe }

       Packet content can be of the following:

          hex bytes:   0xca, xff
          decimal:     42
          binary:      0b11110000, b11110000
          octal:       011
          character:   'a'
          string:      "hello world"
          shellcode:   "\x31\xdb\x8d\x43\x17\x99\xcd\x80\x31\xc9"

       Thus, a quite useless packet configuration might look like this (one
       can verify this when running this with trafgen in combination with
       -V):

          { 0xca, 42, 0b11110000, 011, 'a', "hello world",
            "\x31\xdb\x8d\x43\x17\x99\xcd\x80\x31\xc9" }

       There are a couple of helper functions in trafgen's language to make
       life easier to write configurations:

       i) Fill with garbage functions:

          byte fill function:      fill(<content>, <times>): fill(0xca, 128)
          compile-time random:     rnd(<times>): rnd(128), rnd()
          runtime random numbers:  drnd(<times>): drnd(128), drnd()
          compile-time counter:    seqinc(<start-val>, <increment>, <times>)
                                   seqdec(<start-val>, <decrement>, <times>)
          runtime counter (1byte): dinc(<min-val>, <max-val>, <increment>)
                                   ddec(<min-val>, <max-val>, <decrement>)

       ii) Checksum helper functions (packet offsets start with 0):

          IP/ICMP checksum:        csumip/csumicmp(<off-from>, <off-to>)
          UDP checksum:            csumudp(<off-iphdr>, <off-udpdr>)
          TCP checksum:            csumtcp(<off-iphdr>, <off-tcphdr>)
          UDP checksum (IPv6):     csumudp6(<off-ip6hdr>, <off-udpdr>)
          TCP checksum (IPv6):     csumtcp6(<off-ip6hdr>, <off-tcphdr>)

       iii) Multibyte functions, compile-time expression evaluation:

          const8(<content>), c8(<content>), const16(<content>),
       c16(<content>),
          const32(<content>), c32(<content>), const64(<content>),
       c64(<content>)

          These functions write their result in network byte order into the
       packet configuration, e.g. const16(0xaa) will result in ''00 aa''.
       Within c*() functions, it is possible to do some arithmetics:
       -,+,*,/,%,&,|,<<,>>,^ E.g. const16((((1<<8)+0x32)|0b110)*2) will be
       evaluated to ''02 6c''.

       iv) Protocol header functions:
           The protocol header functions allow to fill protocol header
           fields by using following generic syntax:

               <proto>(<field>=<value>,<field2>=<value2>,...,<field3>,...)

           If a field is not specified, then a default value will be used
           (usually 0).  Protocol fields might be set in any order. However,
           the offset of the fields in the resulting packet is according to
           the respective protocol.

           Each field might be set with a function which generates field
           value at runtime by increment or randomize it. For L3/L4
           protocols the checksum is calculated automatically if the field
           was changed dynamically by specified function.  The following
           field functions are supported:

               dinc - increment field value at runtime. By default increment
               step is '1'.  min and max parameters are used to increment
               field only in the specified range, by default original field
               value is used. If the field length is greater than 4 then
               last 4 bytes are incremented only (useful for MAC and IPv6
               addresses):

                   <field> = dinc() | dinc(min, max) | dinc(min, max, step)

               drnd - randomize field value at runtime.  min and max
               parameters are used to randomize field only in the specified
               range:

                   <field> = drnd() | drnd(min, max)

               Example of using dynamic functions:

               {
                     eth(saddr=aa:bb:cc:dd:ee:ff, saddr=dinc()),
                     ipv4(saddr=dinc()),
                     udp(sport=dinc(1, 13, 2), dport=drnd(80, 100))
               }

           Fields might be further manipulated with a function at a specific
           offset:

               <field>[<index>] | <field>[<index>:<length>]

                   <index> - relative field offset with range 0..<field.len>
                   - 1

                   <length> - length/size of the value which will be set;
                   either 1, 2 or 4 bytes (default: 1)

               The <index> starts from the field's first byte in network
               order.

               The syntax is similar to the one used in pcap filters (man
               pcap-filter) for matching header field at a specified offset.

               Examples of using field offset (showing the effect in a
               shortenet output from netsniff-ng):

                   1) trafgen -o lo --cpus 1 -n 3 '{
                   eth(da=11:22:33:44:55:66, da[0]=dinc()), tcp() }'

                       [ Eth MAC (00:00:00:00:00:00 => 11:22:33:44:55:66)

                       [ Eth MAC (00:00:00:00:00:00 => 12:22:33:44:55:66)

                       [ Eth MAC (00:00:00:00:00:00 => 13:22:33:44:55:66)

                   2) trafgen -o lo --cpus 1 -n 3 '{ ipv4(da=1.2.3.4,
                   da[0]=dinc()), tcp() }'

                       [ IPv4 Addr (127.0.0.1 => 1.2.3.4)

                       [ IPv4 Addr (127.0.0.1 => 2.2.3.4)

                       [ IPv4 Addr (127.0.0.1 => 3.2.3.4)

           All required lower layer headers will be filled automatically if
           they were not specified by the user. The headers will be filled
           in the order they were specified. Each header will be filled with
           some mimimum required set of fields.

           Supported protocol headers:

           Ethernet : eth(da=<mac>, sa=<mac>, type=<number>)

               da|daddr - Destination MAC address (default:
               00:00:00:00:00:00)

               sa|saddr - Source MAC address (default: device MAC address)

               etype|type|prot|proto - Ethernet type (default: 0)

           PAUSE (IEEE 802.3X) : pause(code=<number>, time=<number>)

               code - MAC Control opcode (default: 0x0001)

               time - Pause time (default: 0)

               By default Ethernet header is added with a fields:

                   Ethernet type - 0x8808

                   Destination MAC address - 01:80:C2:00:00:01

           PFC : pfc(pri|prio(<number>)=<number>, time(<number>)=<number>)

               code - MAC Control opcode (default: 0x0101)

               pri|prio - Priority enable vector (default: 0)

               pri|prio(<number>) - Enable/disable (0 - disable, 1 - enable)
               pause for priority <number> (default: 0)

               time(<number>) - Set pause time for priority <number>
               (default: 0)

               By default Ethernet header is added with a fields:

                   Ethernet type - 0x8808

                   Destination MAC address - 01:80:C2:00:00:01

           VLAN : vlan(tpid=<number>, id=<number>, dei=<number>,
           tci=<number>, pcp=<number>, 1q, 1ad)

               tpid|prot|proto - Tag Protocol Identifier (TPID) (default:
               0x8100)

               tci - Tag Control Information (TCI) field (VLAN Id + PCP +
               DEI) (default: 0)

               dei|cfi - Drop Eligible Indicator (DEI), formerly Canonical
               Format Indicator (CFI) (default: 0)

               pcp - Priority code point (PCP) (default: 0)

               id - VLAN Identifier (default: 0)

               1q - Set 802.1q header (TPID: 0x8100)

               1ad - Set 802.1ad header (TPID: 0x88a8)

           By default, if the lower level header is Ethernet, its EtherType
           is set to 0x8100 (802.1q).

           MPLS : mpls(label=<number>, tc|exp=<number>, last=<number>,
           ttl=<number>)

               label|lbl - MPLS label value (default: 0)

               tclass|tc|exp - Traffic Class for QoS field (default: 0)

               last - Bottom of stack S-flag (default: 1 for most last
               label)

               ttl - Time To Live (TTL) (default: 0)

           By default, if the lower level header is Ethernet, its EtherType
           is set to 0x8847 (MPLS Unicast). S-flag is set automatically to 1
           for the last label and resets to 0 if the lower MPLS label was
           added after.

           ARP : arp(htype=<number>, ptype=<number>,
           op=<request|reply|number>, request, reply, smac=<mac>,
           sip=<ip4_addr>, tmac=<mac>, tip=<ip4_addr>)

               htype - ARP hardware type (default: 1 [Ethernet])

               ptype - ARP protocol type (default: 0x0800 [IPv4])

               op - ARP operation type (request/reply) (default: request)

               req|request - ARP Request operation type

               reply - ARP Reply operation type

               smac|sha - Sender hardware (MAC) address (default: device MAC
               address)

               sip|spa - Sender protocol (IPv4) address (default: device
               IPv4 address)

               tmac|tha - Target hardware (MAC) address (default:
               00:00:00:00:00:00)

               tip|tpa - Target protocol (IPv4) address (default: device
               IPv4 address)

           By default, the ARP operation field is set to request and the
           Ethernet destination MAC address is set to the broadcast address
           (ff:ff:ff:ff:ff:ff).

           IPv4 : ip4|ipv4(ihl=<number>, ver=<number>, len=<number>,
           csum=<number>, ttl=<number>, tos=<number>, dscp=<number>,
           ecn=<number>,
                           id=<number>, flags=<number>, frag=<number>, df,
                           mf, da=<ip4_addr>, sa=<ip4_addr>,
                           prot[o]=<number>)

               ver|version - Version field (default: 4)

               ihl - Header length in number of 32-bit words (default: 5)

               tos - Type of Service (ToS) field (default: 0)

               dscp - Differentiated Services Code Point (DSCP, DiffServ)
               field (default: 0)

               ecn - Explicit Congestion Notification (ECN) field (default:
               0)

               len|length - Total length of header and payload (calculated
               by default)

               id - IPv4 datagram identification (default: 0)

               flags - IPv4 flags value (DF, MF) (default: 0)

               df - Don't fragment (DF) flag (default: 0)

               mf - More fragments (MF) flag (default: 0)

               frag - Fragment offset field in number of 8 byte blocks
               (default: 0)

               ttl - Time to live (TTL) field (default: 0)

               csum - Header checksum (calculated by default)

               sa|saddr - Source IPv4 address (default: device IPv4 address)

               da|daddr - Destination IPv4 address (default: 0.0.0.0)

               prot|proto - IPv4 protocol number (default: 0)

           By default, if the lower level header is Ethernet, its EtherType
           field is set to 0x0800 (IPv4). If the lower level header is IPv4,
           its protocol field is set to 0x4 (IP-in-IP).

           IPv6 : ip6|ipv6(ver=<number>, class=<number>, flow=<number>
           len=<number>, nexthdr=<number>, hoplimit=<number>,
                           da=<ip6_addr>, sa=<ip6_addr>)

               ver|version - Version field (default: 6)

               tc|tclass - Traffic class (default: 0)

               fl|flow - Flow label (default: 0)

               len|length - Payload length (calculated by default)

               nh|nexthdr - Type of next header, i.e. transport layer
               protocol number (default: 0)

               hl|hoplimit|ttl - Hop limit, i.e. time to live (default: 0)

               sa|saddr - Source IPv6 address (default: device IPv6 address)

               da|daddr - Destination IPv6 address (default:
               0:0:0:0:0:0:0:0)

           By default, if the lower level header is Ethernet, its EtherType
           field is set to 0x86DD (IPv6).

           ICMPv4 : icmp4|icmpv4(type=<number>, code=<number>, echorequest,
           echoreply, csum=<number>, mtu=<number>, seq=<number>,
           id=<number>, addr=<ip4_addr>)

               type - Message type (default: 0 - Echo reply)

               code - Message code (default: 0)

               echorequest - ICMPv4 echo (ping) request (type: 8, code: 0)

               echoreply - ICMPv4 echo (ping) reply (type: 0, code: 0)

               csum - Checksum of ICMPv4 header and payload (calculated by
               default)

               mtu - Next-hop MTU field used in 'Datagram is too big'
               message type (default; 0)

               seq - Sequence number used in Echo/Timestamp/Address mask
               messages (default: 0)

               id - Identifier used in Echo/Timestamp/Address mask messages
               (default: 0)

               addr - IPv4 address used in Redirect messages (default:
               0.0.0.0)

           Example ICMP echo request (ping):

               { icmpv4(echorequest, seq=1, id=1326) }

           ICMPv6 : icmp6|icmpv6(type=<number>, echorequest, echoreply,
           code=<number>, csum=<number>)

               type - Message type (default: 0)

               code - Code (default: 0)

               echorequest - ICMPv6 echo (ping) request

               echoreply - ICMPv6 echo (ping) reply

               csum - Message checksum (calculated by default)

           By default, if the lower level header is IPv6, its Next Header
           field is set to 58 (ICMPv6).

           UDP : udp(sp=<number>, dp=<number>, len=<number>, csum=<number>)

               sp|sport - Source port (default: 0)

               dp|dport - Destination port (default: 0)

               len|length - Length of UDP header and data (calculated by
               default)

               csum - Checksum field over IPv4 pseudo header (calculated by
               default)

           By default, if the lower level header is IPv4, its protocol field
           is set to 0x11 (UDP).

           TCP : tcp(sp=<number>, dp=<number>, seq=<number>,
           aseq|ackseq=<number>, doff|hlen=<number>, cwr, ece|ecn, urg, ack,
           psh, rst, syn, fin, win|window=<number>, csum=<number>,
           urgptr=<number>)

               sp|sport - Source port (default: 0)

               dp|dport - Destination port (default: 0)

               seq - Sequence number (default: 0)

               aseq|ackseq - Acknowledgement number (default: 0)

               doff|hlen - Header size (data offset) in number of 32-bit
               words (default: 5)

               cwr - Congestion Window Reduced (CWR) flag (default: 0)

               ece|ecn - ECN-Echo (ECE) flag (default: 0)

               urg - Urgent flag (default: 0)

               ack - Acknowledgement flag (default: 0)

               psh - Push flag (default: 0)

               rst - Reset flag (default: 0)

               syn - Synchronize flag (default: 0)

               fin - Finish flag (default: 0)

               win|window - Receive window size (default: 0)

               csum - Checksum field over IPv4 pseudo header (calculated by
               default)

               urgptr - Urgent pointer (default: 0)

           By default, if the lower level header is IPv4, its protocol field
           is set to 0x6 (TCP).

           Simple example of a UDP Echo packet:

               {
                 eth(da=11:22:33:44:55:66),
                 ipv4(daddr=1.2.3.4)
                 udp(dp=7),
                 "Hello world"
               }

       Furthermore, there are two types of comments in trafgen configuration
       files:

         1. Multi-line C-style comments:        /* put comment here */
         2. Single-line Shell-style comments:   #  put comment here

       Next to all of this, a configuration can be passed through the C
       preprocessor before the trafgen compiler gets to see it with option
       --cpp. To give you a taste of a more advanced example, run ''trafgen
       -e'', fields are commented:

          /* Note: dynamic elements make trafgen slower! */
          #include <stddef.h>

          {
            /* MAC Destination */
            fill(0xff, ETH_ALEN),
            /* MAC Source */
            0x00, 0x02, 0xb3, drnd(3),
            /* IPv4 Protocol */
            c16(ETH_P_IP),
            /* IPv4 Version, IHL, TOS */
            0b01000101, 0,
            /* IPv4 Total Len */
            c16(59),
            /* IPv4 Ident */
            drnd(2),
            /* IPv4 Flags, Frag Off */
            0b01000000, 0,
            /* IPv4 TTL */
            64,
            /* Proto TCP */
            0x06,
            /* IPv4 Checksum (IP header from, to) */
            csumip(14, 33),
            /* Source IP */
            drnd(4),
            /* Dest IP */
            drnd(4),
            /* TCP Source Port */
            drnd(2),
            /* TCP Dest Port */
            c16(80),
            /* TCP Sequence Number */
            drnd(4),
            /* TCP Ackn. Number */
            c32(0),
            /* TCP Header length + TCP SYN/ECN Flag */
            c16((8 << 12) | TCP_FLAG_SYN | TCP_FLAG_ECE)
            /* Window Size */
            c16(16),
            /* TCP Checksum (offset IP, offset TCP) */
            csumtcp(14, 34),
            /* TCP Options */
            0x00, 0x00, 0x01, 0x01, 0x08, 0x0a, 0x06,
            0x91, 0x68, 0x7d, 0x06, 0x91, 0x68, 0x6f,
            /* Data blob */
            "gotcha!",
          }

       Another real-world example by Jesper Dangaard Brouer [1]:

          {
            # --- ethernet header ---
            0x00, 0x1b, 0x21, 0x3c, 0x9d, 0xf8,  # mac destination
            0x90, 0xe2, 0xba, 0x0a, 0x56, 0xb4,  # mac source
            const16(0x0800), # protocol
            # --- ip header ---
            # ipv4 version (4-bit) + ihl (4-bit), tos
            0b01000101, 0,
            # ipv4 total len
            const16(40),
            # id (note: runtime dynamic random)
            drnd(2),
            # ipv4 3-bit flags + 13-bit fragment offset
            # 001 = more fragments
            0b00100000, 0,
            64, # ttl
            17, # proto udp
            # dynamic ip checksum (note: offsets are zero indexed)
            csumip(14, 33),
            192, 168, 51, 1, # source ip
            192, 168, 51, 2, # dest ip
            # --- udp header ---
            # as this is a fragment the below stuff does not matter too much
            const16(48054), # src port
            const16(43514), # dst port
            const16(20),    # udp length
            # udp checksum can be dyn calc via csumudp(offset ip, offset
       tcp)
            # which is csumudp(14, 34), but for udp its allowed to be zero
            const16(0),
            # payload
            'A',  fill(0x41, 11),
          }

          [1] https://marc.info/?l=linux-netdev&m=135903630614184

       The above example rewritten using the header generation functions:

          {
            # --- ethernet header ---
            eth(da=00:1b:21:3c:9d:f8, da=90:e2:ba:0a:56:b4)
            # --- ip header ---
            ipv4(id=drnd(), mf, ttl=64, sa=192.168.51.1, da=192.168.51.2)
            # --- udp header ---
            udp(sport=48054, dport=43514, csum=0)
            # payload
            'A',  fill(0x41, 11),
          }

USAGE EXAMPLE         top

   trafgen --dev eth0 --conf trafgen.cfg
       This is the most simple and, probably, the most common use of
       trafgen. It will generate traffic defined in the configuration file
       ''trafgen.cfg'' and transmit this via the ''eth0'' networking device.
       All online CPUs are used.

   trafgen -e | trafgen -i - -o lo --cpp -n 1
       This is an example where we send one packet of the built-in example
       through the loopback device. The example configuration is passed via
       stdin and also through the C preprocessor before trafgen's packet
       compiler will see it.

   trafgen --dev eth0 --conf fuzzing.cfg --smoke-test 10.0.0.1
       Read the ''fuzzing.cfg'' packet configuration file (which contains
       drnd() calls) and send out the generated packets to the ''eth0''
       device. After each sent packet, ping probe the attacked host with
       address 10.0.0.1 to check if it's still alive. This also means, that
       we utilize 1 CPU only, and do not use the TX_RING, but sendto(2)
       packet I/O due to ''slow mode''.

   trafgen --dev wlan0 --rfraw --conf beacon-test.txf -V --cpus 2
       As an output device ''wlan0'' is used and put into monitoring mode,
       thus we are going to transmit raw 802.11 frames through the air. Use
       the
        ''beacon-test.txf'' configuration file, set trafgen into verbose
       mode and use only 2 CPUs.

   trafgen --dev em1 --conf frag_dos.cfg --rand --gap 1000us
       Use trafgen in sendto(2) mode instead of TX_RING mode and sleep after
       each sent packet a static timegap for 1000us. Generate packets from
       ''frag_dos.cfg'' and select next packets to send randomly instead of
       a round-robin fashion.  The output device for packets is ''em1''.

   trafgen --dev eth0 --conf icmp.cfg --rand --num 1400000 -k1000
       Send only 1400000 packets using the ''icmp.cfg'' configuration file
       and then exit trafgen. Select packets randomly from that file for
       transmission and send them out via ''eth0''. Also, trigger the kernel
       every 1000us for batching the ring frames from user space (default is
       10us).

   trafgen --dev eth0 --conf tcp_syn.cfg -u `id -u bob` -g `id -g bob`
       Send out packets generated from the configuration file
       ''tcp_syn.cfg'' via the ''eth0'' networking device. After setting up
       the ring for transmission, drop credentials to the non-root
       user/group bob/bob.

   trafgen --dev eth0 '{ fill(0xff, 6), 0x00, 0x02, 0xb3, rnd(3),
       c16(0x0800), fill(0xca, 64) }' -n 1
       Send out 1 invaid IPv4 packet built from command line to all hosts.

NOTE         top

       trafgen can saturate a Gigabit Ethernet link without problems. As
       always, of course, this depends on your hardware as well. Not
       everywhere where it says Gigabit Ethernet on the box, will you reach
       almost physical line rate!  Please also read the netsniff-ng(8) man
       page, section NOTE for further details about tuning your system e.g.
       with tuned(8).

       If you intend to use trafgen on a 10-Gbit/s Ethernet NIC, make sure
       you are using a multiqueue tc(8) discipline, and make sure that the
       packets you generate with trafgen will have a good distribution among
       tx_hashes so that you'll actually make use of multiqueues.

       For introducing bit errors, delays with random variation and more,
       there is no built-in option in trafgen. Rather, one should reuse
       existing methods for that which integrate nicely with trafgen, such
       as tc(8) with its different disciplines, i.e. netem.

       For more complex packet configurations, it is recommended to use
       high-level scripting for generating trafgen packet configurations in
       a more automated way, i.e. also to create different traffic
       distributions that are common for industrial benchmarking:

           Traffic model              Distribution

           IMIX                       64:7,  570:4,  1518:1
           Tolly                      64:55,  78:5,   576:17, 1518:23
           Cisco                      64:7,  594:4,  1518:1
           RPR Trimodal               64:60, 512:20, 1518:20
           RPR Quadrimodal            64:50, 512:15, 1518:15, 9218:20

       The low-level nature of trafgen makes trafgen rather protocol
       independent and therefore useful in many scenarios when stress
       testing is needed, for instance. However, if a traffic generator with
       higher level packet descriptions is desired, netsniff-ng's
       mausezahn(8) can be of good use as well.

       For smoke/fuzz testing with trafgen, it is recommended to have a
       direct link between the host you want to analyze (''victim'' machine)
       and the host you run trafgen on (''attacker'' machine). If the ICMP
       reply from the victim fails, we assume that probably its kernel
       crashed, thus we print the last sent packet together with the seed
       and quit probing. It might be very unlikely to find such a ping-of-
       death on modern Linux systems. However, there might be a good chance
       to find it on some proprietary (e.g. embedded) systems or buggy
       driver firmwares that are in the wild. Also, fuzz testing can be done
       on raw 802.11 frames, of course. In case you find a ping-of-death,
       please mention that you were using trafgen in your commit message of
       the fix!

BUGS         top

       For old trafgen versions only, there could occur kernel crashes: we
       have fixed this bug in the mainline and stable kernels under commit
       7f5c3e3a8 (''af_packet: remove BUG statement in
       tpacket_destruct_skb'') and also in trafgen.

       Probably the best is if you upgrade trafgen to the latest version.

LEGAL         top

       trafgen is licensed under the GNU GPL version 2.0.

HISTORY         top

       trafgen was originally written for the netsniff-ng toolkit by Daniel
       Borkmann. It is currently maintained by Tobias Klauser
       <tklauser@distanz.ch> and Daniel Borkmann <dborkma@tik.ee.ethz.ch>.

SEE ALSO         top

       netsniff-ng(8), mausezahn(8), ifpps(8), bpfc(8), flowtop(8),
       astraceroute(8), curvetun(8)

AUTHOR         top

       Manpage was written by Daniel Borkmann.

COLOPHON         top

       This page is part of the Linux netsniff-ng toolkit project. A
       description of the project, and information about reporting bugs, can
       be found at http://netsniff-ng.org/.

COLOPHON         top

       This page is part of the netsniff-ng (a free Linux networking
       toolkit) project.  Information about the project can be found at 
       ⟨http://netsniff-ng.org/⟩.  If you have a bug report for this manual
       page, send it to netsniff-ng@googlegroups.com.  This page was
       obtained from the project's upstream Git repository 
       ⟨git://github.com/netsniff-ng/netsniff-ng.git⟩ on 2017-03-13.  If you
       discover any rendering problems in this HTML version of the page, or
       you believe there is a better or more up-to-date source for the page,
       or you have corrections or improvements to the information in this
       COLOPHON (which is not part of the original manual page), send a mail
       to man-pages@man7.org

Linux                           03 March 2013                     TRAFGEN(8)