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如何调试 ip xfrm 规则

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如何调试 ip xfrm 规则

我在 2 台机器上创建了 ip xfrm 规则，并尝试通过 ipsec 隧道传输流量。数据包进入另一端，加密后消失。

我通过 iptables 跟踪了它们，以下是跟踪结果。

2015-11-27T14:50:21.442638+04:30 cfae kernel: [70234.667488] TRACE: raw:PREROUTING:policy:2 IN=eth0 OUT= MAC=00:0c:29:b7:97:49:00:0c:29:42:5b:e1:08:00 SRC=172.24.1.178 DST=10.60.60.31 LEN=128 TOS=0x00 PREC=0x00 TTL=61 ID=0 DF PROTO=UDP SPT=4500 DPT=4500 LEN=108 
2015-11-27T14:50:21.442665+04:30 cfae kernel: [70234.667513] TRACE: mangle:PREROUTING:rule:2 IN=eth0 OUT= MAC=00:0c:29:b7:97:49:00:0c:29:42:5b:e1:08:00 SRC=172.24.1.178 DST=10.60.60.31 LEN=128 TOS=0x00 PREC=0x00 TTL=61 ID=0 DF PROTO=UDP SPT=4500 DPT=4500 LEN=108 
2015-11-27T14:50:21.442672+04:30 cfae kernel: [70234.667580] TRACE: mangle:INPUT:policy:1 IN=eth0 OUT= MAC=00:0c:29:b7:97:49:00:0c:29:42:5b:e1:08:00 SRC=172.24.1.178 DST=10.60.60.31 LEN=128 TOS=0x00 PREC=0x00 TTL=61 ID=0 DF PROTO=UDP SPT=4500 DPT=4500 LEN=108 
2015-11-27T14:50:21.442674+04:30 cfae kernel: [70234.667589] TRACE: filter:INPUT:policy:1 IN=eth0 OUT= MAC=00:0c:29:b7:97:49:00:0c:29:42:5b:e1:08:00 SRC=172.24.1.178 DST=10.60.60.31 LEN=128 TOS=0x00 PREC=0x00 TTL=61 ID=0 DF PROTO=UDP SPT=4500 DPT=4500 LEN=108 
2015-11-27T14:50:21.471390+04:30 cfae kernel: [70234.696166] TRACE: raw:PREROUTING:policy:2 IN=eth0 OUT= MAC=00:0c:29:b7:97:49:00:0c:29:42:5b:e1:08:00 SRC=172.24.1.178 DST=10.60.60.31 LEN=128 TOS=0x00 PREC=0x00 TTL=61 ID=0 DF PROTO=UDP SPT=4500 DPT=4500 LEN=108 
2015-11-27T14:50:21.471401+04:30 cfae kernel: [70234.696184] TRACE: mangle:PREROUTING:rule:2 IN=eth0 OUT= MAC=00:0c:29:b7:97:49:00:0c:29:42:5b:e1:08:00 SRC=172.24.1.178 DST=10.60.60.31 LEN=128 TOS=0x00 PREC=0x00 TTL=61 ID=0 DF PROTO=UDP SPT=4500 DPT=4500 LEN=108 
2015-11-27T14:50:21.471408+04:30 cfae kernel: [70234.696225] TRACE: mangle:INPUT:policy:1 IN=eth0 OUT= MAC=00:0c:29:b7:97:49:00:0c:29:42:5b:e1:08:00 SRC=172.24.1.178 DST=10.60.60.31 LEN=128 TOS=0x00 PREC=0x00 TTL=61 ID=0 DF PROTO=UDP SPT=4500 DPT=4500 LEN=108 
2015-11-27T14:50:21.471409+04:30 cfae kernel: [70234.696234] TRACE: filter:INPUT:policy:1 IN=eth0 OUT= MAC=00:0c:29:b7:97:49:00:0c:29:42:5b:e1:08:00 SRC=172.24.1.178 DST=10.60.60.31 LEN=128 TOS=0x00 PREC=0x00 TTL=61 ID=0 DF PROTO=UDP SPT=4500 DPT=4500 LEN=108 
2015-11-27T14:50:21.695777+04:30 cfae kernel: [70234.920757] TRACE: raw:PREROUTING:policy:2 IN=eth0 OUT= MAC=00:0c:29:b7:97:49:00:0c:29:42:5b:e1:08:00 SRC=172.24.1.178 DST=10.60.60.31 LEN=128 TOS=0x00 PREC=0x00 TTL=61 ID=0 DF PROTO=UDP SPT=4500 DPT=4500 LEN=108 
2015-11-27T14:50:21.695801+04:30 cfae kernel: [70234.920804] TRACE: mangle:PREROUTING:rule:2 IN=eth0 OUT= MAC=00:0c:29:b7:97:49:00:0c:29:42:5b:e1:08:00 SRC=172.24.1.178 DST=10.60.60.31 LEN=128 TOS=0x00 PREC=0x00 TTL=61 ID=0 DF PROTO=UDP SPT=4500 DPT=4500 LEN=108 
2015-11-27T14:50:21.695808+04:30 cfae kernel: [70234.920847] TRACE: mangle:INPUT:policy:1 IN=eth0 OUT= MAC=00:0c:29:b7:97:49:00:0c:29:42:5b:e1:08:00 SRC=172.24.1.178 DST=10.60.60.31 LEN=128 TOS=0x00 PREC=0x00 TTL=61 ID=0 DF PROTO=UDP SPT=4500 DPT=4500 LEN=108 
2015-11-27T14:50:21.695810+04:30 cfae kernel: [70234.920875] TRACE: filter:INPUT:policy:1 IN=eth0 OUT= MAC=00:0c:29:b7:97:49:00:0c:29:42:5b:e1:08:00 SRC=172.24.1.178 DST=10.60.60.31 LEN=128 TOS=0x00 PREC=0x00 TTL=61 ID=0 DF PROTO=UDP SPT=4500 DPT=4500 LEN=108

从跟踪中，我看到数据包从 filter:INPUT 返回到 raw:PREROUTING，这意味着它必须经过 xfrm 查找/解码处理。但数据包经过此处理后没有变化（长度相同，源/目标地址相同）。

但是“ip -s xfrm state”显示 0 个失败/已处理的数据包。

有什么方法可以通过 xfrm 模块跟踪这些数据包吗？或者有没有办法启用 xfrm 的调试？

这是配置。

    On Machine1: 
    # ip xfrm state
    src 10.60.60.31 dst 172.24.1.178
        proto esp spi 0x5fca3acb reqid 212013014 mode tunnel
        replay-window 0 
        auth-trunc hmac(sha512) 0xc2dde59416e78c96b9b0333686b3cf0b09016bb1c1d27215d3dbf7aca471304a1c25536eb2648b3dcd8946047007389d06eb3fb4c4e9379630acae51bd755b07 96
        enc cbc(aes) 0x944023fd181e13d401f80e2166654b549b758aeeb9f382a20ca967631b111ef0
        encap type espinudp sport 4500 dport 4500 addr 10.60.60.31
        sel src 0.0.0.0/0 dst 0.0.0.0/0 
    src 172.24.1.178 dst 10.60.60.31
        proto esp spi 0x5fca3acb reqid 212013014 mode tunnel
        replay-window 0 
        mark 212013014/0xffffffff
        auth-trunc hmac(sha512) 0xc2dde59416e78c96b9b0333686b3cf0b09016bb1c1d27215d3dbf7aca471304a1c25536eb2648b3dcd8946047007389d06eb3fb4c4e9379630acae51bd755b07 96
        enc cbc(aes) 0x944023fd181e13d401f80e2166654b549b758aeeb9f382a20ca967631b111ef0
        encap type espinudp sport 4500 dport 4500 addr 172.24.1.178
        sel src 0.0.0.0/0 dst 0.0.0.0/0 
    # ip xfrm policy
    src 0.0.0.0/0 dst 0.0.0.0/0 
        dir fwd priority 65535 
        tmpl src 10.60.60.31 dst 172.24.1.178
            proto esp spi 0x5fca3acb reqid 212013014 mode tunnel
            level use 
    src 0.0.0.0/0 dst 0.0.0.0/0 
        dir in priority 65535 
        tmpl src 10.60.60.31 dst 172.24.1.178
            proto esp spi 0x5fca3acb reqid 212013014 mode tunnel
            level use 
    src 0.0.0.0/0 dst 0.0.0.0/0 
        dir out priority 65535 
        mark 212013014/0xffffffff
        tmpl src 172.24.1.178 dst 10.60.60.31
            proto esp spi 0x5fca3acb reqid 212013014 mode tunnel
            level use 


    On Machine2:
    # ip xfrm policy
src 0.0.0.0/0 dst 0.0.0.0/0 
    dir fwd priority 65535 
    tmpl src 172.24.1.178 dst 10.60.60.31
        proto esp spi 0x5fca3acb reqid 212012972 mode tunnel
        level use 
src 0.0.0.0/0 dst 0.0.0.0/0 
    dir in priority 65535 
    tmpl src 172.24.1.178 dst 10.60.60.31
        proto esp spi 0x5fca3acb reqid 212012972 mode tunnel
        level use 
src 0.0.0.0/0 dst 0.0.0.0/0 
    dir out priority 65535 
    mark 212012972/0xffffffff
    tmpl src 10.60.60.31 dst 172.24.1.178
        proto esp spi 0x5fca3acb reqid 212012972 mode tunnel
        level use 
# ip xfrm state
src 172.24.1.178 dst 10.60.60.31
    proto esp spi 0x5fca3acb reqid 212012972 mode tunnel
    replay-window 0 
    auth-trunc hmac(sha512) 0xc2dde59416e78c96b9b0333686b3cf0b09016bb1c1d27215d3dbf7aca471304a1c25536eb2648b3dcd8946047007389d06eb3fb4c4e9379630acae51bd755b07 96
    enc cbc(aes) 0x944023fd181e13d401f80e2166654b549b758aeeb9f382a20ca967631b111ef0
    encap type espinudp sport 4500 dport 4500 addr 172.24.1.178
    sel src 0.0.0.0/0 dst 0.0.0.0/0 
src 10.60.60.31 dst 172.24.1.178
    proto esp spi 0x5fca3acb reqid 212012972 mode tunnel
    replay-window 0 
    mark 212012972/0xffffffff
    auth-trunc hmac(sha512) 0xc2dde59416e78c96b9b0333686b3cf0b09016bb1c1d27215d3dbf7aca471304a1c25536eb2648b3dcd8946047007389d06eb3fb4c4e9379630acae51bd755b07 96
    enc cbc(aes) 0x944023fd181e13d401f80e2166654b549b758aeeb9f382a20ca967631b111ef0
    encap type espinudp sport 4500 dport 4500 addr 10.60.60.31
    sel src 0.0.0.0/0 dst 0.0.0.0/0

答案1

要调试 xfrm，您可以使用命令ip xfrm monitor。

它将显示数据库策略的变化。它将显示每个数据包的处理。

答案2

http://techblog.newsnow.co.uk/2011/11/simple-udp-esp-encapsulation-nat-t-for.html

看来，如果没有某些指令，Linux 内核不会解封装数据包。我们需要绑定到传入 udp 端口​​上的套接字并启用 udp 封装。上面的链接有 perl 脚本可以执行此操作。此后，我的流量没有任何问题。

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