1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486 487 488 489 490 491 492 493 494 495 496 497 498 499 500 501 502 503 504 505 506 507 508 509 510 511 512 513 514 515 516 517 518 519 520 521 522 523 524 525 526 527 528 529 530 531 532 533 534 535 536 537 538 539 540 541 542 543 544 545 546 547 548 549 550 551 552 553 554 555 556 557 558 559 560 561 562 563 564 565 566 567 568 569 570 571 572 573 574 575 576 577 578 579 580 581 582 583 584 585 586 587 588 589 590 591 592 593 594 595 596 597 598 599 600 601 602 603 604 605 606 607 608 609 610 611 612 613 614 615 616 617 618 619 620 621 622 623 624 625 626 627 628 629 630 631 632 633 634 635 636 637 638 639 640 641 642 643 644 645 646 647 648 649 650 651 652 653 654 655 656 657 658 659 660 661 662 663 664 665 666 667 668 669 670 671 672 673 674 675 676 677 678 679 680 681 682 683 684 685 686 687 688 689 690 691 692 693 694 695 696 697 698 699 700 701 702 703 704 705 706 707 708 709 710 711 712 713 714 715 716 717 718 719 720 721 722 723 724 725 726 727 728 729 730 731 732 733 734 735 736 737 738 739 740 741 742 743 744 745 746 747 748 749 750 751 752 753 754 755 756 757 758 759 760 761 762 763 764 765 766 767 768 769 770 771 772 773 774 775 776 777 778 779 780 781 782 783 784 785 786 787 788 789 790 791 792 793 794 795 796 797 798 799 800 801 802 803 804 805 806 807 808 809 810 811 812 813 814 815 816 817 818 819 820 821 822 823 824 825 826 827 828 829 830 831 832 833 834 835 836 837 838 839 840 841 842 843 844 845 846 847 848 849 850 851 852 853 854 855 856 857 858 859 860 861 862 863 864 865 866 867 868 869 870 871 872 873 874 875 876 877 878 879 880 881 882 883 884 885 886 887 888 889 890 891 892 893 894 895 896 897 898 899 900 901 902 903 904 905 906 907 908 909 910 911 912 913 914 915 916 917 918 919 920 921 922 923 924 925 926 927 928 929 930 931 932 933 934 935 936 937 938 939 940 941 942 943 944 945 946 947 948 949 950 951 952 953 954 955 956 957 958 959 960 961 962 963 964 965 966 967 968 969 970 971 972 973 974 975 976 977 978 979 980 981 982 983 984 985 986 987 988 989 990 991 992 993 994 995 996 997 998 999 1000 1001 1002 1003 1004 1005 1006 1007 1008 1009 1010 1011 1012 1013 1014 1015 1016 1017 1018 1019 1020 1021 1022 1023 1024 1025 1026 1027 1028 1029 1030 1031 1032 1033 1034 1035 1036 1037 1038 1039 1040 1041 1042 1043 1044 1045 1046 1047 1048 1049
|
.\" netsniff-ng - the packet sniffing beast
.\" Copyright 2013 Daniel Borkmann.
.\" Subject to the GPL, version 2.
.TH TRAFGEN 8 "03 March 2013" "Linux" "netsniff-ng toolkit"
.SH NAME
trafgen \- a fast, multithreaded network packet generator
.PP
.SH SYNOPSIS
.PP
\fBtrafgen\fP [\fIoptions\fP] [\fIpacket\fP]
.PP
.SH DESCRIPTION
.PP
trafgen is a fast, zero-copy network traffic generator for debugging,
performance evaluation, and fuzz-testing. trafgen utilizes the
.BR 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.
.PP
trafgen is Linux specific, meaning there is no support for other operating
systems, same as
.BR netsniff-ng (8),
thus we can keep the code footprint quite minimal and to the point. trafgen
makes use of
.BR packet (7)
socket's TX_RING interface of the Linux kernel, which is a
.BR mmap (2)'ed
ring buffer shared between user and kernel space.
.PP
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.
.PP
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.
.PP
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,
.BR netsniff-ng (8)
is able to convert a pcap file into a trafgen configuration file, thus such a
configuration can be further tweaked for a given scenario.
.PP
.SH OPTIONS
.TP
.B -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
\fB-i\fP/\fB--in\fP option, by default packets will be sent at rate considering
timestamp from PCAP file which might be reset via the \fB-b\fP or \fB-t\fP option.
.TP
.B -o <dev|.pcap|.cfg>, -d <dev|.pcap|.cfg>, --out <dev|.pcap|.cfg>, --dev <dev|.pcap|.cfg>
Defines the outgoing networking device such as eth0, wlan0 and others or
a *.pcap or *.cfg file. Pcap and configuration files are identified by extension.
.TP
.B -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.
.TP
.B -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 \fB-p\fP/\fB--cpp\fP option.
.TP
.B -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.
.TP
.B -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. In case if the output is a pcap file the link type
is set to 127 (ieee80211 radio tap).
.TP
.B -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.
.TP
.B -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.
.TP
.B -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.
.TP
.B -P <uint>, --cpus <uint>
Specify the number of processes trafgen shall
.BR 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].
.TP
.B -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
.BR packet (7)'s
TX_RING interface, trafgen will use
.BR sendto (2)
I/O for network packets, even if the <time> argument is 0. This option is useful
for a couple of reasons:
1) comparison between
.BR sendto (2)
and TX_RING performance,
2) low-traffic packet probing for a given interval,
3) ping-like debugging with specific payload patterns.
Furthermore, the TX_RING interface does not cope with interpacket gaps.
.TP
.B -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 \fB-t\fP/\fB--gap\fP option, the packets are sent in slow mode.
.TP
.B -S <size>, --ring-size <size>
Manually define the TX_RING resp. TX_RING size in ''<num>KiB/MiB/GiB''. By
default the size is being determined based on the network connectivity rate.
.TP
.B -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.
.TP
.B -u <uid>, --user <uid> resp. -g <gid>, --group <gid>
After ring setup, drop privileges to a non-root user/group combination.
.TP
.B -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.
.TP
.B -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
.TP
.B -Q, --notouch-irq
Do not reassign the NIC's IRQ CPU affinity settings.
.TP
.B -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.
.TP
.B -V, --verbose
Let trafgen be more talkative and let it print the parsed configuration and
some ring buffer statistics.
.TP
.B -e, --example
Show a built-in packet configuration example. This might be a good starting
point for an initial packet configuration scenario.
.TP
.B -C, --no-cpu-stats
Do not print CPU time statistics on exit.
.TP
.B -v, --version
Show version information and exit.
.TP
.B -h, --help
Show user help and exit.
.PP
.SH SYNTAX
.PP
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:
.PP
{ /* packet 1 content goes here ... */ }
{ /* packet 2 content goes here ... */ }
.PP
Alternatively, packets can also be specified directly on the command line, using
the same syntax as used in the configuration files.
.PP
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:
.PP
cpu(1): { /* packet 1 content goes here ... */ }
cpu(2-3): { /* packet 2 content goes here ... */ }
.PP
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.
.PP
Packet content is delimited either by a comma or whitespace, or both:
.PP
{ 0xca, 0xfe, 0xba 0xbe }
.PP
Packet content can be of the following:
.PP
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"
.PP
Thus, a quite useless packet configuration might look like this (one can verify
this when running this with trafgen in combination with \-V):
.PP
{ 0xca, 42, 0b11110000, 011, 'a', "hello world",
"\\x31\\xdb\\x8d\\x43\\x17\\x99\\xcd\\x80\\x31\\xc9" }
.PP
There are a couple of helper functions in trafgen's language to make life easier
to write configurations:
.PP
.B i) Fill with garbage functions:
.PP
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>)
.PP
.B ii) Checksum helper functions (packet offsets start with 0):
.PP
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>)
.PP
.B iii) Multibyte functions, compile-time expression evaluation:
.PP
const8(<content>), c8(<content>), const16(<content>), c16(<content>),
const32(<content>), c32(<content>), const64(<content>), c64(<content>)
.PP
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''.
.PP
.B iv) Protocol header functions:
.in +4
The protocol header functions allow to fill protocol header fields by
using following generic syntax:
.sp
.in +4
<proto>(<field>=<value>,<field2>=<value2>,...,<field3>,...)
.in -4
.sp
.in -4
.in +4
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.
.sp
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:
.in +4
.sp
.B dinc
- increment field value at runtime. By default increment step is '1'.
.B min
and
.B 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):
.in +4
.sp
<field> = dinc() | dinc(min, max) | dinc(min, max, step)
.in -4
.sp
.B drnd
- randomize field value at runtime.
.B min
and
.B max
parameters are used to randomize field only in the specified range:
.in +4
.sp
<field> = drnd() | drnd(min, max)
.in -4
.sp
Example of using dynamic functions:
.sp
{
.in +2
eth(saddr=aa:bb:cc:dd:ee:ff, saddr=dinc()),
ipv4(saddr=dinc()),
udp(sport=dinc(1, 13, 2), dport=drnd(80, 100))
.in -2
}
.in -4
.sp
Fields might be further manipulated with a function at a specific offset:
.sp
.in +4
<field>[<index>] | <field>[<index>:<length>]
.sp
.in +4
<index> - relative field offset with range 0..<field.len> - 1
.sp
<length> - length/size of the value which will be set; either 1, 2 or 4 bytes (default: 1)
.in -4
.sp
The <index> starts from the field's first byte in network order.
.sp
The syntax is similar to the one used in pcap filters (man pcap-filter) for
matching header field at a specified offset.
.sp
Examples of using field offset (showing the effect in a shortenet output from
netsniff-ng):
.sp
.in +4
1) trafgen -o lo --cpus 1 -n 3 '{ eth(da=11:22:33:44:55:66, da[0]=dinc()), tcp() }'
.in +4
[ 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)
.in -4
2) trafgen -o lo --cpus 1 -n 3 '{ ipv4(da=1.2.3.4, da[0]=dinc()), tcp() }'
.in +4
[ 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)
.in -4
.in -4
.in -4
.sp
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.
.in -4
.sp
.in +4
Supported protocol headers:
.sp
.I Ethernet
:
.B eth(da=<mac>, sa=<mac>, type=<number>)
.sp
.in +4
.B da|daddr
- Destination MAC address (default: 00:00:00:00:00:00)
.sp
.B sa|saddr
- Source MAC address (default: device MAC address)
.sp
.B etype|type|prot|proto
- Ethernet type (default: 0)
.in -4
.sp
.I PAUSE (IEEE 802.3X)
:
.B pause(code=<number>, time=<number>)
.sp
.in +4
.B code
- MAC Control opcode (default: 0x0001)
.sp
.B time
- Pause time (default: 0)
.sp
By default Ethernet header is added with a fields:
.in +4
.sp
Ethernet type - 0x8808
.sp
Destination MAC address - 01:80:C2:00:00:01
.in -4
.in -4
.sp
.I PFC
:
.B pfc(pri|prio(<number>)=<number>, time(<number>)=<number>)
.sp
.in +4
.B code
- MAC Control opcode (default: 0x0101)
.sp
.B pri|prio
- Priority enable vector (default: 0)
.sp
.B pri|prio(<number>)
- Enable/disable (0 - disable, 1 - enable) pause for priority <number> (default: 0)
.sp
.B time(<number>)
- Set pause time for priority <number> (default: 0)
.sp
By default Ethernet header is added with a fields:
.in +4
.sp
Ethernet type - 0x8808
.sp
Destination MAC address - 01:80:C2:00:00:01
.in -4
.in -4
.I VLAN
:
.B vlan(tpid=<number>, id=<number>, dei=<number>, tci=<number>, pcp=<number>, 1q, 1ad)
.sp
.in +4
.B tpid|prot|proto
- Tag Protocol Identifier (TPID) (default: 0x8100)
.sp
.B tci
- Tag Control Information (TCI) field (VLAN Id + PCP + DEI) (default: 0)
.sp
.B dei|cfi
- Drop Eligible Indicator (DEI), formerly Canonical Format Indicator (CFI) (default: 0)
.sp
.B pcp
- Priority code point (PCP) (default: 0)
.sp
.B id
- VLAN Identifier (default: 0)
.sp
.B 1q
- Set 802.1q header (TPID: 0x8100)
.sp
.B 1ad
- Set 802.1ad header (TPID: 0x88a8)
.sp
.in -4
By default, if the lower level header is Ethernet, its EtherType is set to
0x8100 (802.1q).
.sp
.I MPLS
:
.B mpls(label=<number>, tc|exp=<number>, last=<number>, ttl=<number>)
.sp
.in +4
.B label|lbl
- MPLS label value (default: 0)
.sp
.B tclass|tc|exp
- Traffic Class for QoS field (default: 0)
.sp
.B last
- Bottom of stack S-flag (default: 1 for most last label)
.sp
.B ttl
- Time To Live (TTL) (default: 0)
.sp
.in -4
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.
.sp
.I ARP
:
.B arp(htype=<number>, ptype=<number>, op=<request|reply|number>, request,
.B reply, smac=<mac>, sip=<ip4_addr>, tmac=<mac>, tip=<ip4_addr>)
.sp
.in +4
.B htype
- ARP hardware type (default: 1 [Ethernet])
.sp
.B ptype
- ARP protocol type (default: 0x0800 [IPv4])
.sp
.B op
- ARP operation type (request/reply) (default: request)
.sp
.B req|request
- ARP Request operation type
.sp
.B reply
- ARP Reply operation type
.sp
.B smac|sha
- Sender hardware (MAC) address (default: device MAC address)
.sp
.B sip|spa
- Sender protocol (IPv4) address (default: device IPv4 address)
.sp
.B tmac|tha
- Target hardware (MAC) address (default: 00:00:00:00:00:00)
.sp
.B tip|tpa
- Target protocol (IPv4) address (default: device IPv4 address)
.in -4
.sp
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).
.I IPv4
:
.B ip4|ipv4(ihl=<number>, ver=<number>, len=<number>, csum=<number>,
.B ttl=<number>, tos=<number>, dscp=<number>, ecn=<number>,
.in +16
.B id=<number>, flags=<number>, frag=<number>, df, mf, da=<ip4_addr>, sa=<ip4_addr>,
.B prot[o]=<number>)
.in -16
.sp
.in +4
.B ver|version
- Version field (default: 4)
.sp
.B ihl
- Header length in number of 32-bit words (default: 5)
.sp
.B tos
- Type of Service (ToS) field (default: 0)
.sp
.B dscp
- Differentiated Services Code Point (DSCP, DiffServ) field (default: 0)
.sp
.B ecn
- Explicit Congestion Notification (ECN) field (default: 0)
.sp
.B len|length
- Total length of header and payload (calculated by default)
.sp
.B id
- IPv4 datagram identification (default: 0)
.sp
.B flags
- IPv4 flags value (DF, MF) (default: 0)
.sp
.B df
- Don't fragment (DF) flag (default: 0)
.sp
.B mf
- More fragments (MF) flag (default: 0)
.sp
.B frag
- Fragment offset field in number of 8 byte blocks (default: 0)
.sp
.B ttl
- Time to live (TTL) field (default: 0)
.sp
.B csum
- Header checksum (calculated by default)
.sp
.B sa|saddr
- Source IPv4 address (default: device IPv4 address)
.sp
.B da|daddr
- Destination IPv4 address (default: 0.0.0.0)
.sp
.B prot|proto
- IPv4 protocol number (default: 0)
.in -4
.sp
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).
.I IPv6
:
.B ip6|ipv6(ver=<number>, class=<number>, flow=<number> len=<number>,
.B nexthdr=<number>, hoplimit=<number>,
.in +16
.B da=<ip6_addr>, sa=<ip6_addr>)
.in -16
.sp
.in +4
.B ver|version
- Version field (default: 6)
.sp
.B tc|tclass
- Traffic class (default: 0)
.sp
.B fl|flow
- Flow label (default: 0)
.sp
.B len|length
- Payload length (calculated by default)
.sp
.B nh|nexthdr
- Type of next header, i.e. transport layer protocol number (default: 0)
.sp
.B hl|hoplimit|ttl
- Hop limit, i.e. time to live (default: 0)
.sp
.B sa|saddr
- Source IPv6 address (default: device IPv6 address)
.sp
.B da|daddr
- Destination IPv6 address (default: 0:0:0:0:0:0:0:0)
.in -4
.sp
By default, if the lower level header is Ethernet, its EtherType field is set to
0x86DD (IPv6).
.I ICMPv4
:
.B icmp4|icmpv4(type=<number>, code=<number>, echorequest, echoreply,
.B csum=<number>, mtu=<number>, seq=<number>, id=<number>, addr=<ip4_addr>)
.sp
.in +4
.B type
- Message type (default: 0 - Echo reply)
.sp
.B code
- Message code (default: 0)
.sp
.B echorequest
- ICMPv4 echo (ping) request (type: 8, code: 0)
.sp
.B echoreply
- ICMPv4 echo (ping) reply (type: 0, code: 0)
.sp
.B csum
- Checksum of ICMPv4 header and payload (calculated by default)
.sp
.B mtu
- Next-hop MTU field used in 'Datagram is too big' message type (default; 0)
.sp
.B seq
- Sequence number used in Echo/Timestamp/Address mask messages (default: 0)
.sp
.B id
- Identifier used in Echo/Timestamp/Address mask messages (default: 0)
.sp
.B addr
- IPv4 address used in Redirect messages (default: 0.0.0.0)
.sp
.in -4
Example ICMP echo request (ping):
.in +4
.sp
{ icmpv4(echorequest, seq=1, id=1326) }
.in -4
.I ICMPv6
:
.B icmp6|icmpv6(type=<number>, echorequest, echoreply, code=<number>,
.B csum=<number>)
.sp
.in +4
.B type
- Message type (default: 0)
.sp
.B code
- Code (default: 0)
.sp
.B echorequest
- ICMPv6 echo (ping) request
.sp
.B echoreply
- ICMPv6 echo (ping) reply
.sp
.B csum
- Message checksum (calculated by default)
.in -4
.sp
By default, if the lower level header is IPv6, its Next Header field is set to
58 (ICMPv6).
.I UDP
:
.B udp(sp=<number>, dp=<number>, len=<number>, csum=<number>)
.sp
.in +4
.B sp|sport
- Source port (default: 0)
.sp
.B dp|dport
- Destination port (default: 0)
.sp
.B len|length
- Length of UDP header and data (calculated by default)
.sp
.B csum
- Checksum field over IPv4 pseudo header (calculated by default)
.sp
.in -4
By default, if the lower level header is IPv4, its protocol field is set to
0x11 (UDP).
.I TCP
:
.B tcp(sp=<number>, dp=<number>, seq=<number>, aseq|ackseq=<number>, doff|hlen=<number>,
.B cwr, ece|ecn, urg, ack, psh, rst, syn, fin, win|window=<number>, csum=<number>,
.B urgptr=<number>)
.sp
.in +4
.B sp|sport
- Source port (default: 0)
.sp
.B dp|dport
- Destination port (default: 0)
.sp
.B seq
- Sequence number (default: 0)
.sp
.B aseq|ackseq
- Acknowledgement number (default: 0)
.sp
.B doff|hlen
- Header size (data offset) in number of 32-bit words (default: 5)
.sp
.B cwr
- Congestion Window Reduced (CWR) flag (default: 0)
.sp
.B ece|ecn
- ECN-Echo (ECE) flag (default: 0)
.sp
.B urg
- Urgent flag (default: 0)
.sp
.B ack
- Acknowledgement flag (default: 0)
.sp
.B psh
- Push flag (default: 0)
.sp
.B rst
- Reset flag (default: 0)
.sp
.B syn
- Synchronize flag (default: 0)
.sp
.B fin
- Finish flag (default: 0)
.sp
.B win|window
- Receive window size (default: 0)
.sp
.B csum
- Checksum field over IPv4 pseudo header (calculated by default)
.sp
.B urgptr
- Urgent pointer (default: 0)
.sp
.in -4
By default, if the lower level header is IPv4, its protocol field is set to
0x6 (TCP).
Simple example of a UDP Echo packet:
.PP
.in +5
{
eth(da=11:22:33:44:55:66),
ipv4(daddr=1.2.3.4)
udp(dp=7),
"Hello world"
}
.in -5
.PP
Furthermore, there are two types of comments in trafgen configuration files:
.PP
1. Multi-line C-style comments: /* put comment here */
2. Single-line Shell-style comments: # put comment here
.PP
Next to all of this, a configuration can be passed through the C preprocessor
before the trafgen compiler gets to see it with option \fB--cpp\fP. To give you a
taste of a more advanced example, run ''trafgen \-e'', fields are commented:
.PP
/* 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!",
}
.PP
Another real-world example by Jesper Dangaard Brouer [1]:
.PP
{
# --- 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),
}
.PP
[1] https://marc.info/?l=linux-netdev&m=135903630614184
.PP
The above example rewritten using the header generation functions:
.PP
{
# --- 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),
}
.PP
.SH USAGE EXAMPLE
.TP
.B 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.
.TP
.B 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.
.TP
.B 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''.
.TP
.B 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.
.TP
.B 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''.
.TP
.B 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).
.TP
.B 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.
.TP
.B 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.
.PP
.SH NOTE
.PP
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
.BR netsniff-ng (8)
man page, section NOTE for further details about tuning your system e.g. with
.BR tuned (8).
.PP
If you intend to use trafgen on a 10-Gbit/s Ethernet NIC, make sure you
are using a multiqueue
.BR 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.
.PP
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
.BR tc (8)
with its different disciplines, i.e. \fBnetem\fP.
.PP
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:
.PP
Traffic model Distribution
.PP
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
.PP
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.
.PP
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!
.PP
.SH BUGS
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.
.PP
Probably the best is if you upgrade trafgen to the latest version.
.PP
.SH LEGAL
trafgen is licensed under the GNU GPL version 2.0.
.PP
.SH HISTORY
.B 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>.
.PP
.SH SEE ALSO
.BR netsniff-ng (8),
.BR mausezahn (8),
.BR ifpps (8),
.BR bpfc (8),
.BR flowtop (8),
.BR astraceroute (8),
.BR curvetun (8)
.PP
.SH AUTHOR
Manpage was written by Daniel Borkmann.
.PP
.SH COLOPHON
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/.
|