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Linux中netfilter与VRF的示例分析

发表于:2024-11-19 作者:千家信息网编辑
千家信息网最后更新 2024年11月19日,这篇文章主要介绍了Linux中netfilter与VRF的示例分析,具有一定借鉴价值,感兴趣的朋友可以参考下,希望大家阅读完这篇文章之后大有收获,下面让小编带着大家一起了解一下。Linux netfi
千家信息网最后更新 2024年11月19日Linux中netfilter与VRF的示例分析

这篇文章主要介绍了Linux中netfilter与VRF的示例分析,具有一定借鉴价值,感兴趣的朋友可以参考下,希望大家阅读完这篇文章之后大有收获,下面让小编带着大家一起了解一下。

实验环境如下图所示:

配置如下:

#!/bin/bashsudo ip netns add ns1 sudo ip link add ns1veth2 type veth peer name eth0 netns ns1sudo ip netns add ns2sudo ip link add ns2veth2 type veth peer name eth0 netns ns2sudo ip link set ns1veth2 master vrftestsudo ip link set ns2veth2 master vrftestsudo ip link set ns2veth2 upsudo ip link set ns1veth2 upsudo ip addr add 1.1.1.254/24 dev ns1veth2 sudo ip addr add 2.2.2.254/24 dev ns2veth2 sudo ip netns exec ns2 ip addr add 2.2.2.1/24 dev eth0 sudo ip netns exec ns1 ip addr add 1.1.1.1/24 dev eth0 sudo ip netns exec ns1 ip link set eth0 upsudo ip netns exec ns1 ip link set lo upsudo ip netns exec ns1 ip route add default via 1.1.1.254 dev eth0sudo ip netns exec ns2 ip link set eth0 upsudo ip netns exec ns2 ip link set lo upsudo ip netns exec ns2 ip route add default via 2.2.2.254 dev eth0sudo iptables -t mangle -A PREROUTING   -s 1.1.1.1 -j LOG --log-prefix="vrf-test-prerouting" sudo iptables -t mangle -A FORWARD      -s 1.1.1.1 -j LOG --log-prefix="vrf-test-forward" sudo iptables -t mangle -A POSTROUTING  -s 1.1.1.1 -j LOG --log-prefix="vrf-test-postrouting" sudo iptables -t mangle -A PREROUTING   -d 1.1.1.1 -j LOG --log-prefix="vrf-test-prerouting" sudo iptables -t mangle -A FORWARD      -d 1.1.1.1 -j LOG --log-prefix="vrf-test-forward" sudo iptables -t mangle -A POSTROUTING  -d 1.1.1.1 -j LOG --log-prefix="vrf-test-postrouting" sudo iptables -t mangle -A INPUT        -d 1.1.1.1 -j LOG --log-prefix="vrf-test-localin" sudo iptables -t mangle -A INPUT        -s 1.1.1.1 -j LOG --log-prefix="vrf-test-localin" sudo iptables -t mangle -A OUTPUT       -s 1.1.1.1 -j LOG --log-prefix="vrf-test-localout" sudo iptables -t mangle -A OUTPUT       -d 1.1.1.1 -j LOG --log-prefix="vrf-test-localout"

外网访问本机

ns1 ping 网关1.1.1.254

admin@ubuntu:~$ sudo ip netns exec ns1 ping 1.1.1.254 -c 1       PING 1.1.1.254 (1.1.1.254) 56(84) bytes of data.64 bytes from 1.1.1.254: icmp_seq=1 ttl=64 time=0.064 ms--- 1.1.1.254 ping statistics ---1 packets transmitted, 1 received, 0% packet loss, time 0msrtt min/avg/max/mdev = 0.064/0.064/0.064/0.000 msadmin@ubuntu:~$

查看log

Nov 20 20:34:10 ubuntu kernel: [180403.527204] vrf-test-preroutingIN=ns1veth2 OUT= MAC=b2:f8:2a:13:31:75:6e:17:d5:b2:55:14:08:00 SRC=1.1.1.1 DST=1.1.1.254 LEN=84 TOS=0x00 PREC=0x00 TTL=64 ID=32492 DF PROTO=ICMP TYPE=8 CODE=0 ID=33955 SEQ=1 Nov 20 20:34:10 ubuntu kernel: [180403.527213] vrf-test-preroutingIN=vrftest OUT= MAC=b2:f8:2a:13:31:75:6e:17:d5:b2:55:14:08:00 SRC=1.1.1.1 DST=1.1.1.254 LEN=84 TOS=0x00 PREC=0x00 TTL=64 ID=32492 DF PROTO=ICMP TYPE=8 CODE=0 ID=33955 SEQ=1 Nov 20 20:34:10 ubuntu kernel: [180403.527220] vrf-test-localinIN=vrftest OUT= MAC=b2:f8:2a:13:31:75:6e:17:d5:b2:55:14:08:00 SRC=1.1.1.1 DST=1.1.1.254 LEN=84 TOS=0x00 PREC=0x00 TTL=64 ID=32492 DF PROTO=ICMP TYPE=8 CODE=0 ID=33955 SEQ=1 Nov 20 20:34:10 ubuntu kernel: [180403.527231] vrf-test-localoutIN= OUT=vrftest SRC=1.1.1.254 DST=1.1.1.1 LEN=84 TOS=0x00 PREC=0x00 TTL=64 ID=54845 PROTO=ICMP TYPE=0 CODE=0 ID=33955 SEQ=1 Nov 20 20:34:10 ubuntu kernel: [180403.527233] vrf-test-postroutingIN= OUT=vrftest SRC=1.1.1.254 DST=1.1.1.1 LEN=84 TOS=0x00 PREC=0x00 TTL=64 ID=54845 PROTO=ICMP TYPE=0 CODE=0 ID=33955 SEQ=1 Nov 20 20:34:10 ubuntu kernel: [180403.527235] vrf-test-localoutIN= OUT=ns1veth2 SRC=1.1.1.254 DST=1.1.1.1 LEN=84 TOS=0x00 PREC=0x00 TTL=64 ID=54845 PROTO=ICMP TYPE=0 CODE=0 ID=33955 SEQ=1 Nov 20 20:34:10 ubuntu kernel: [180403.527242] vrf-test-postroutingIN= OUT=ns1veth2 SRC=1.1.1.254 DST=1.1.1.1 LEN=84 TOS=0x00 PREC=0x00 TTL=64 ID=54845 PROTO=ICMP TYPE=0 CODE=0 ID=33955 SEQ=1

从log可以看出:

请求报文经过的hook点顺序如下:

序号hook点输入接口输出接口
1PREROUTINGns1veth2
2PREROUTINGvrftest
3INPUTvrftest

应答报文经过的hook点顺序如下:

序号hook点输入接口输出接口
1OUTPUTvrftest
2POSTROUTINGvrftest
3OUTPUTns1veth2
4POSTROUTINGns1veth2

转发报文

ns1 ping ns2

admin@ubuntu:~$ sudo ip netns exec ns1 ping 2.2.2.1 -c 1PING 2.2.2.1 (2.2.2.1) 56(84) bytes of data.64 bytes from 2.2.2.1: icmp_seq=1 ttl=63 time=0.063 ms--- 2.2.2.1 ping statistics ---1 packets transmitted, 1 received, 0% packet loss, time 0msrtt min/avg/max/mdev = 0.063/0.063/0.063/0.000 msadmin@ubuntu:~$

查看log

Nov 20 20:28:31 ubuntu kernel: [180065.076713] vrf-test-preroutingIN=ns1veth2 OUT= MAC=b2:f8:2a:13:31:75:6e:17:d5:b2:55:14:08:00 SRC=1.1.1.1 DST=2.2.2.1 LEN=84 TOS=0x00 PREC=0x00 TTL=64 ID=38312 DF PROTO=ICMP TYPE=8 CODE=0 ID=33948 SEQ=1 Nov 20 20:28:31 ubuntu kernel: [180065.076722] vrf-test-preroutingIN=vrftest OUT= MAC=b2:f8:2a:13:31:75:6e:17:d5:b2:55:14:08:00 SRC=1.1.1.1 DST=2.2.2.1 LEN=84 TOS=0x00 PREC=0x00 TTL=64 ID=38312 DF PROTO=ICMP TYPE=8 CODE=0 ID=33948 SEQ=1 Nov 20 20:28:31 ubuntu kernel: [180065.076730] vrf-test-forwardIN=vrftest OUT=ns2veth2 MAC=b2:f8:2a:13:31:75:6e:17:d5:b2:55:14:08:00 SRC=1.1.1.1 DST=2.2.2.1 LEN=84 TOS=0x00 PREC=0x00 TTL=63 ID=38312 DF PROTO=ICMP TYPE=8 CODE=0 ID=33948 SEQ=1 Nov 20 20:28:31 ubuntu kernel: [180065.076732] vrf-test-postroutingIN= OUT=ns2veth2 SRC=1.1.1.1 DST=2.2.2.1 LEN=84 TOS=0x00 PREC=0x00 TTL=63 ID=38312 DF PROTO=ICMP TYPE=8 CODE=0 ID=33948 SEQ=1 Nov 20 20:28:31 ubuntu kernel: [180065.076746] vrf-test-preroutingIN=ns2veth2 OUT= MAC=02:25:0e:fe:52:35:ba:19:4d:37:ac:8b:08:00 SRC=2.2.2.1 DST=1.1.1.1 LEN=84 TOS=0x00 PREC=0x00 TTL=64 ID=47601 PROTO=ICMP TYPE=0 CODE=0 ID=33948 SEQ=1 Nov 20 20:28:31 ubuntu kernel: [180065.076749] vrf-test-preroutingIN=vrftest OUT= MAC=02:25:0e:fe:52:35:ba:19:4d:37:ac:8b:08:00 SRC=2.2.2.1 DST=1.1.1.1 LEN=84 TOS=0x00 PREC=0x00 TTL=64 ID=47601 PROTO=ICMP TYPE=0 CODE=0 ID=33948 SEQ=1 Nov 20 20:28:31 ubuntu kernel: [180065.076752] vrf-test-forwardIN=vrftest OUT=ns1veth2 MAC=02:25:0e:fe:52:35:ba:19:4d:37:ac:8b:08:00 SRC=2.2.2.1 DST=1.1.1.1 LEN=84 TOS=0x00 PREC=0x00 TTL=63 ID=47601 PROTO=ICMP TYPE=0 CODE=0 ID=33948 SEQ=1 Nov 20 20:28:31 ubuntu kernel: [180065.076753] vrf-test-postroutingIN= OUT=ns1veth2 SRC=2.2.2.1 DST=1.1.1.1 LEN=84 TOS=0x00 PREC=0x00 TTL=63 ID=47601 PROTO=ICMP TYPE=0 CODE=0 ID=33948 SEQ=1

从log可以看出:

请求报文经过的hook点顺序如下:

序号hook点输入接口输出接口
1PREROUTINGns1veth2
2PREROUTINGvrftest
3FORWARDvrftestns2veth2
4POSTROUTINGns2veth2

应答报文经过的hook点顺序如下:

序号hook点输入接口输出接口
1PREROUTINGns2veth2
2PREROUTINGvrftest
3FORWARDvrftestns2veth2
4POSTROUTINGns2veth2

本机访问外网

vrftest ping 1.1.1.1

admin@ubuntu:~$ sudo ping 1.1.1.1 -I vrftest -c 1ping: Warning: source address might be selected on device other than vrftest.PING 1.1.1.1 (1.1.1.1) from 1.1.1.254 vrftest: 56(84) bytes of data.64 bytes from 1.1.1.1: icmp_seq=1 ttl=64 time=0.039 ms--- 1.1.1.1 ping statistics ---1 packets transmitted, 1 received, 0% packet loss, time 0msrtt min/avg/max/mdev = 0.039/0.039/0.039/0.000 msadmin@ubuntu:~$

查看log

Nov 20 21:21:11 ubuntu kernel: [183224.956734] vrf-test-localoutIN= OUT=vrftest SRC=1.1.1.254 DST=1.1.1.1 LEN=84 TOS=0x00 PREC=0x00 TTL=64 ID=35042 DF PROTO=ICMP TYPE=8 CODE=0 ID=34186 SEQ=1 Nov 20 21:21:11 ubuntu kernel: [183224.956740] vrf-test-postroutingIN= OUT=vrftest SRC=1.1.1.254 DST=1.1.1.1 LEN=84 TOS=0x00 PREC=0x00 TTL=64 ID=35042 DF PROTO=ICMP TYPE=8 CODE=0 ID=34186 SEQ=1 Nov 20 21:21:11 ubuntu kernel: [183224.956745] vrf-test-localoutIN= OUT=ns1veth2 SRC=1.1.1.254 DST=1.1.1.1 LEN=84 TOS=0x00 PREC=0x00 TTL=64 ID=35042 DF PROTO=ICMP TYPE=8 CODE=0 ID=34186 SEQ=1 Nov 20 21:21:11 ubuntu kernel: [183224.956746] vrf-test-postroutingIN= OUT=ns1veth2 SRC=1.1.1.254 DST=1.1.1.1 LEN=84 TOS=0x00 PREC=0x00 TTL=64 ID=35042 DF PROTO=ICMP TYPE=8 CODE=0 ID=34186 SEQ=1 Nov 20 21:21:11 ubuntu kernel: [183224.956762] vrf-test-preroutingIN=ns1veth2 OUT= MAC=b2:f8:2a:13:31:75:6e:17:d5:b2:55:14:08:00 SRC=1.1.1.1 DST=1.1.1.254 LEN=84 TOS=0x00 PREC=0x00 TTL=64 ID=323 PROTO=ICMP TYPE=0 CODE=0 ID=34186 SEQ=1 Nov 20 21:21:11 ubuntu kernel: [183224.956765] vrf-test-preroutingIN=vrftest OUT= MAC=b2:f8:2a:13:31:75:6e:17:d5:b2:55:14:08:00 SRC=1.1.1.1 DST=1.1.1.254 LEN=84 TOS=0x00 PREC=0x00 TTL=64 ID=323 PROTO=ICMP TYPE=0 CODE=0 ID=34186 SEQ=1 Nov 20 21:21:11 ubuntu kernel: [183224.956769] vrf-test-localinIN=vrftest OUT= MAC=b2:f8:2a:13:31:75:6e:17:d5:b2:55:14:08:00 SRC=1.1.1.1 DST=1.1.1.254 LEN=84 TOS=0x00 PREC=0x00 TTL=64 ID=323 PROTO=ICMP TYPE=0 CODE=0 ID=34186 SEQ=1

从log可以看出:

请求报文经过的hook点顺序如下:

序号hook点输入接口输出接口
1OUTPUTvrftest
2POSTROUTINGvrftest
3OUTPUTns1veth2
4POSTROUTINGns1veth2

应答报文经过的hook点顺序如下:

序号hook点输入接口输出接口
1PREROUTINGns1veth2
2PREROUTINGvrftest
3INPUTvrftest

本机访问本机,即环回

vrftest ping vrf接口地址9.9.9.9/24

添加如下netfilter规则:

admin@ubuntu:~/vrftcpdump$ cat netfilter1.sh sudo iptables -t mangle -A PREROUTING   -s 9.9.9.9 -j LOG --log-prefix="vrf-test-prerouting" sudo iptables -t mangle -A FORWARD      -s 9.9.9.9 -j LOG --log-prefix="vrf-test-forward" sudo iptables -t mangle -A POSTROUTING  -s 9.9.9.9 -j LOG --log-prefix="vrf-test-postrouting"sudo iptables -t mangle -A INPUT        -s 9.9.9.9 -j LOG --log-prefix="vrf-test-localin" sudo iptables -t mangle -A OUTPUT       -s 9.9.9.9 -j LOG --log-prefix="vrf-test-localout" admin@ubuntu:~/vrftcpdump$

配置vrftest接口地址为9.9.9.9/24

admin@ubuntu:~/vrftcpdump$ sudo ip addr add 9.9.9.9/24 dev vrftest           admin@ubuntu:~/vrftcpdump$ sudo ping 9.9.9.9 -I vrftest -c 1             PING 9.9.9.9 (9.9.9.9) from 9.9.9.9 vrftest: 56(84) bytes of data.64 bytes from 9.9.9.9: icmp_seq=1 ttl=64 time=0.050 ms--- 9.9.9.9 ping statistics ---1 packets transmitted, 1 received, 0% packet loss, time 0msrtt min/avg/max/mdev = 0.050/0.050/0.050/0.000 msadmin@ubuntu:~/vrftcpdump$

查看log

Nov 20 22:13:41 ubuntu kernel: [186374.589186] vrf-test-localoutIN= OUT=vrftest SRC=9.9.9.9 DST=9.9.9.9 LEN=84 TOS=0x00 PREC=0x00 TTL=64 ID=39425 DF PROTO=ICMP TYPE=8 CODE=0 ID=34815 SEQ=1 Nov 20 22:13:41 ubuntu kernel: [186374.589192] vrf-test-postroutingIN= OUT=vrftest SRC=9.9.9.9 DST=9.9.9.9 LEN=84 TOS=0x00 PREC=0x00 TTL=64 ID=39425 DF PROTO=ICMP TYPE=8 CODE=0 ID=34815 SEQ=1 Nov 20 22:13:41 ubuntu kernel: [186374.589202] vrf-test-preroutingIN=vrftest OUT= MAC=ca:f9:f0:37:4c:6c:ca:f9:f0:37:4c:6c:08:00 SRC=9.9.9.9 DST=9.9.9.9 LEN=84 TOS=0x00 PREC=0x00 TTL=64 ID=39425 DF PROTO=ICMP TYPE=8 CODE=0 ID=34815 SEQ=1 Nov 20 22:13:41 ubuntu kernel: [186374.589204] vrf-test-localinIN=vrftest OUT= MAC=ca:f9:f0:37:4c:6c:ca:f9:f0:37:4c:6c:08:00 SRC=9.9.9.9 DST=9.9.9.9 LEN=84 TOS=0x00 PREC=0x00 TTL=64 ID=39425 DF PROTO=ICMP TYPE=8 CODE=0 ID=34815 SEQ=1 Nov 20 22:13:41 ubuntu kernel: [186374.589210] vrf-test-localoutIN= OUT=vrftest SRC=9.9.9.9 DST=9.9.9.9 LEN=84 TOS=0x00 PREC=0x00 TTL=64 ID=39426 PROTO=ICMP TYPE=0 CODE=0 ID=34815 SEQ=1 Nov 20 22:13:41 ubuntu kernel: [186374.589211] vrf-test-postroutingIN= OUT=vrftest SRC=9.9.9.9 DST=9.9.9.9 LEN=84 TOS=0x00 PREC=0x00 TTL=64 ID=39426 PROTO=ICMP TYPE=0 CODE=0 ID=34815 SEQ=1 Nov 20 22:13:41 ubuntu kernel: [186374.589215] vrf-test-preroutingIN=vrftest OUT= MAC=ca:f9:f0:37:4c:6c:ca:f9:f0:37:4c:6c:08:00 SRC=9.9.9.9 DST=9.9.9.9 LEN=84 TOS=0x00 PREC=0x00 TTL=64 ID=39426 PROTO=ICMP TYPE=0 CODE=0 ID=34815 SEQ=1 Nov 20 22:13:41 ubuntu kernel: [186374.589217] vrf-test-localinIN=vrftest OUT= MAC=ca:f9:f0:37:4c:6c:ca:f9:f0:37:4c:6c:08:00 SRC=9.9.9.9 DST=9.9.9.9 LEN=84 TOS=0x00 PREC=0x00 TTL=64 ID=39426 PROTO=ICMP TYPE=0 CODE=0 ID=34815 SEQ=1

从log可以看出:

请求报文经过的hook点顺序如下:

序号hook点输入接口输出接口
1OUTPUTvrftest
2POSTROUTINGvrftest
3PREROUTINGvrftest
4INPUTvrftest

应答报文经过的hook点顺序如下:

序号hook点输入接口输出接口
1OUTPUTvrftest
2POSTROUTINGvrftest
3PREROUTINGvrftest
4INPUTvrftest

环回请求和应答是一样的。

总结

  • linux内核支持VRF后,报文会两次进入PREROUTING节点,第一次是原始接口,第二次是原始接口依附的vrf主接口。

  • linux内核支持VRF后,本机输出的报文,先以vrf接口作为输出接口经过OUTPUT和POSTROUTING节点,然后再以真实出去的接口经过OUPUT和POSTROUTING节点。

  • 本机报文进行环回时,与没有VRF的环境是一样的。

感谢你能够认真阅读完这篇文章,希望小编分享的"Linux中netfilter与VRF的示例分析"这篇文章对大家有帮助,同时也希望大家多多支持,关注行业资讯频道,更多相关知识等着你来学习!

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