HOWTO for the linux packet generator 
                    ------------------------------------
  
  Date: 041221
  
  Enable CONFIG_NET_PKTGEN to compile and build pktgen.o either in kernel
  or as module. Module is preferred. insmod pktgen if needed. Once running

  pktgen creates a thread on each CPU where each thread has affinity to its CPU.

  Monitoring and controlling is done via /proc. Easiest to select a suitable 
  a sample script and configure.
  
  On a dual CPU:
  
  ps aux | grep pkt
  root       129  0.3  0.0     0    0 ?        SW    2003 523:20 [pktgen/0]
  root       130  0.3  0.0     0    0 ?        SW    2003 509:50 [pktgen/1]

  For monitoring and control pktgen creates:

  	/proc/net/pktgen/pgctrl
  	/proc/net/pktgen/kpktgend_X
          /proc/net/pktgen/ethX
  
  
  Viewing threads
  ===============
  /proc/net/pktgen/kpktgend_0 
  Name: kpktgend_0  max_before_softirq: 10000
  Running: 
  Stopped: eth1 
  Result: OK: max_before_softirq=10000

  Most important the devices assigned to thread. Note! A device can only belong 

  to one thread.
  
  
  Viewing devices
  ===============
  
  Parm section holds configured info. Current hold running stats. 
  Result is printed after run or after interruption. Example:
  
  /proc/net/pktgen/eth1       
  
  Params: count 10000000  min_pkt_size: 60  max_pkt_size: 60
       frags: 0  delay: 0  clone_skb: 1000000  ifname: eth1
       flows: 0 flowlen: 0
       dst_min: 10.10.11.2  dst_max: 
       src_min:   src_max: 
       src_mac: 00:00:00:00:00:00  dst_mac: 00:04:23:AC:FD:82
       udp_src_min: 9  udp_src_max: 9  udp_dst_min: 9  udp_dst_max: 9
       src_mac_count: 0  dst_mac_count: 0 
       Flags: 
  Current:
       pkts-sofar: 10000000  errors: 39664
       started: 1103053986245187us  stopped: 1103053999346329us idle: 880401us
       seq_num: 10000011  cur_dst_mac_offset: 0  cur_src_mac_offset: 0
       cur_saddr: 0x10a0a0a  cur_daddr: 0x20b0a0a
       cur_udp_dst: 9  cur_udp_src: 9
       flows: 0
  Result: OK: 13101142(c12220741+d880401) usec, 10000000 (60byte,0frags)
    763292pps 390Mb/sec (390805504bps) errors: 39664

  Configuring threads and devices
  ================================

  This is done via the /proc interface easiest done via pgset in the scripts
  
  Examples:
  
   pgset "clone_skb 1"     sets the number of copies of the same packet
   pgset "clone_skb 0"     use single SKB for all transmits
   pgset "pkt_size 9014"   sets packet size to 9014
   pgset "frags 5"         packet will consist of 5 fragments
   pgset "count 200000"    sets number of packets to send, set to zero

                           for continuous sends until explicitly stopped.

  
   pgset "delay 5000"      adds delay to hard_start_xmit(). nanoseconds
  
   pgset "dst 10.0.0.1"    sets IP destination address
                           (BEWARE! This generator is very aggressive!)
  
   pgset "dst_min 10.0.0.1"            Same as dst
   pgset "dst_max 10.0.0.254"          Set the maximum destination IP.
   pgset "src_min 10.0.0.1"            Set the minimum (or only) source IP.
   pgset "src_max 10.0.0.254"          Set the maximum source IP.
   pgset "dst6 fec0::1"     IPV6 destination address
   pgset "src6 fec0::2"     IPV6 source address
   pgset "dstmac 00:00:00:00:00:00"    sets MAC destination address
   pgset "srcmac 00:00:00:00:00:00"    sets MAC source address

   pgset "queue_map_min 0" Sets the min value of tx queue interval
   pgset "queue_map_max 7" Sets the max value of tx queue interval, for multiqueue devices
                           To select queue 1 of a given device,
                           use queue_map_min=1 and queue_map_max=1

   pgset "src_mac_count 1" Sets the number of MACs we'll range through.  
                           The 'minimum' MAC is what you set with srcmac.
  
   pgset "dst_mac_count 1" Sets the number of MACs we'll range through.
                           The 'minimum' MAC is what you set with dstmac.
  
   pgset "flag [name]"     Set a flag to determine behaviour.  Current flags
                           are: IPSRC_RND #IP Source is random (between min/max),
                                IPDST_RND, UDPSRC_RND,
                                UDPDST_RND, MACSRC_RND, MACDST_RND 

                                MPLS_RND, VID_RND, SVID_RND

                                QUEUE_MAP_RND # queue map random
                                QUEUE_MAP_CPU # queue map mirrors smp_processor_id()

  
   pgset "udp_src_min 9"   set UDP source port min, If < udp_src_max, then
                           cycle through the port range.
  
   pgset "udp_src_max 9"   set UDP source port max.
   pgset "udp_dst_min 9"   set UDP destination port min, If < udp_dst_max, then
                           cycle through the port range.
   pgset "udp_dst_max 9"   set UDP destination port max.

   pgset "mpls 0001000a,0002000a,0000000a" set MPLS labels (in this example
                                           outer label=16,middle label=32,
  					 inner label=0 (IPv4 NULL)) Note that
  					 there must be no spaces between the
  					 arguments. Leading zeros are required.
  					 Do not set the bottom of stack bit,

  					 that's done automatically. If you do

  					 set the bottom of stack bit, that
  					 indicates that you want to randomly
  					 generate that address and the flag
  					 MPLS_RND will be turned on. You
  					 can have any mix of random and fixed
  					 labels in the label stack.
  
   pgset "mpls 0"		  turn off mpls (or any invalid argument works too!)

   pgset "vlan_id 77"       set VLAN ID 0-4095
   pgset "vlan_p 3"         set priority bit 0-7 (default 0)
   pgset "vlan_cfi 0"       set canonical format identifier 0-1 (default 0)
  
   pgset "svlan_id 22"      set SVLAN ID 0-4095
   pgset "svlan_p 3"        set priority bit 0-7 (default 0)
   pgset "svlan_cfi 0"      set canonical format identifier 0-1 (default 0)
  
   pgset "vlan_id 9999"     > 4095 remove vlan and svlan tags
   pgset "svlan 9999"       > 4095 remove svlan tag
  
  
   pgset "tos XX"           set former IPv4 TOS field (e.g. "tos 28" for AF11 no ECN, default 00)
   pgset "traffic_class XX" set former IPv6 TRAFFIC CLASS (e.g. "traffic_class B8" for EF no ECN, default 00)

   pgset stop    	          aborts injection. Also, ^C aborts generator.

   pgset "rate 300M"        set rate to 300 Mb/s
   pgset "ratep 1000000"    set rate to 1Mpps

  
  Example scripts
  ===============

  A collection of small tutorial scripts for pktgen is in examples dir.

  
  pktgen.conf-1-1                  # 1 CPU 1 dev 
  pktgen.conf-1-2                  # 1 CPU 2 dev
  pktgen.conf-2-1                  # 2 CPU's 1 dev 
  pktgen.conf-2-2                  # 2 CPU's 2 dev
  pktgen.conf-1-1-rdos             # 1 CPU 1 dev w. route DoS 
  pktgen.conf-1-1-ip6              # 1 CPU 1 dev ipv6
  pktgen.conf-1-1-ip6-rdos         # 1 CPU 1 dev ipv6  w. route DoS
  pktgen.conf-1-1-flows            # 1 CPU 1 dev multiple flows.
  
  Run in shell: ./pktgen.conf-X-Y It does all the setup including sending. 
  
  
  Interrupt affinity
  ===================
  Note when adding devices to a specific CPU there good idea to also assign 
  /proc/irq/XX/smp_affinity so the TX-interrupts gets bound to the same CPU.
  as this reduces cache bouncing when freeing skb's.
  
  
  Current commands and configuration options
  ==========================================
  
  ** Pgcontrol commands:
  
  start
  stop
  
  ** Thread commands:
  
  add_device
  rem_device_all
  max_before_softirq
  
  
  ** Device commands:
  
  count
  clone_skb
  debug
  
  frags
  delay
  
  src_mac_count
  dst_mac_count
  
  pkt_size 
  min_pkt_size
  max_pkt_size

  mpls

  udp_src_min
  udp_src_max
  
  udp_dst_min
  udp_dst_max
  
  flag
    IPSRC_RND
    TXSIZE_RND
    IPDST_RND
    UDPSRC_RND
    UDPDST_RND
    MACSRC_RND
    MACDST_RND
  
  dst_min
  dst_max
  
  src_min
  src_max
  
  dst_mac
  src_mac
  
  clear_counters
  
  dst6
  src6
  
  flows
  flowlen

  rate
  ratep

  References:
  ftp://robur.slu.se/pub/Linux/net-development/pktgen-testing/
  ftp://robur.slu.se/pub/Linux/net-development/pktgen-testing/examples/
  
  Paper from Linux-Kongress in Erlangen 2004.
  ftp://robur.slu.se/pub/Linux/net-development/pktgen-testing/pktgen_paper.pdf
  
  Thanks to:
  Grant Grundler for testing on IA-64 and parisc, Harald Welte,  Lennert Buytenhek
  Stephen Hemminger, Andi Kleen, Dave Miller and many others.

  Good luck with the linux net-development.