什么是 pktgen
pktgen 是一款 Linux 发包工具，可在内核高速发包。
Linux packet generator is a tool to generate packets at very high speed in the kernel.
使能 pktgen
内核配置文件开启 CONFIG_NET_PKTGEN，通过查看是否有 /proc/net/pktgen/ 目录确认是否编译 OK。
使用 pktgen 发包
添加设备
echo "add_device eth3" > /proc/net/pktgen/kpktgend_0
配置报文
配置方法，样例仅给出部分配置
echo "pkt_size 64" > /proc/net/pktgen/eth3
echo "count 1000000" > /proc/net/pktgen/eth3
echo "dst_mac aa:bb:cc:dd:ee:ff" > /proc/net/pktgen/eth3
查看配置结果：
cat /proc/net/pktgen/eth3
发送报文
echo "start" > /proc/net/pktgen/pgctrl
查看发送结果：
cat /proc/net/pktgen/eth3
发包样例
[1209-20:29:14:517] root@ubuntu:/proc/net/pktgen# echo "pkt_size 1500" > /proc/net/pktgen/eth3
[1209-20:29:26:980] root@ubuntu:/proc/net/pktgen# echo "count 1000000" > /proc/net/pktgen/eth3
[1209-20:29:29:862] root@ubuntu:/proc/net/pktgen# echo "start" > /proc/net/pktgen/pgctrl
[1209-20:29:48:407] root@ubuntu:/proc/net/pktgen# cat /proc/net/pktgen/eth3
[1209-20:29:48:430] Params: count 1000000 min_pkt_size: 1500 max_pkt_size: 1500
[1209-20:29:48:435] frags: 0 delay: 0 clone_skb: 0 ifname: eth3
[1209-20:29:48:437] flows: 0 flowlen: 0
[1209-20:29:48:441] queue_map_min: 0 queue_map_max: 0
[1209-20:29:48:444] dst_min: dst_max:
[1209-20:29:48:447] src_min: src_max:
[1209-20:29:48:452] src_mac: 02:10:18:2c:f8:0e dst_mac: 00:00:00:00:00:00
[1209-20:29:48:458] udp_src_min: 9 udp_src_max: 9 udp_dst_min: 9 udp_dst_max: 9
[1209-20:29:48:460] src_mac_count: 0 dst_mac_count: 0
[1209-20:29:48:464] Flags:
[1209-20:29:48:464] Current:
[1209-20:29:48:467] pkts-sofar: 1000000 errors: 0
[1209-20:29:48:472] started: 3219370012us stopped: 3233111900us idle: 299798us
[1209-20:29:48:477] seq_num: 1000001 cur_dst_mac_offset: 0 cur_src_mac_offset: 0
[1209-20:29:48:481] cur_saddr: 192.168.2.1 cur_daddr: 0.0.0.0
[1209-20:29:48:486] cur_udp_dst: 9 cur_udp_src: 9
[1209-20:29:48:490] cur_queue_map: 0
[1209-20:29:48:491] flows: 0
[1209-20:29:48:496] Result: OK: 13741888(c13442090+d299798) usec, 1000000 (1500byte,0frags)
[1209-20:29:48:499] 72770pps 873Mb/sec (873240000bps) errors: 0
[1209-20:30:05:839] root@ubuntu:/proc/net/pktgen#
完整说明
From linuxfoundation.org pktgen（http://www.linuxfoundation.org/collaborate/workgroups/networking/pktgen）：
Setup
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 affinty it's 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 montoring and control pktgen creates:
/proc/net/pktgen/pgctrl
/proc/net/pktgen/kpktgend_X
# cat /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.
*/proc/net/pktgen/ethX
Param section holds configured info. Current hold running stats. Result is printed after run or after interruption. Example:
# cat /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
Confguring
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 continious sends untill explicitl stopped.
pgset "delay 5000" adds delay to hard_start_xmit(). nanoseconds
pgset "dst 10.0.0.1" sets IP destination addres
(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 "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
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 stop aborts injection. Also, ^C aborts generator.
Examples
A collection of small tutorial scripts for pktgen is in expamples 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.
Commands
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
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