On 7/29/16 12:21 PM, subas...@codeaurora.org wrote:
Please don't try to workaround a bug with a sysctl.
If we have a bug here, we should fix it. Choosing
between bug A and bug B with a sysctl is not what
we are doing ;)
Sure, this was just a quick hack.
Can you give an example of your use case -- e.g., commands for others
(me) to reproduce?
Here is an equivalent set of rules. We see a difference in the oif when
reset oif vs preserve it.
eth1 is the interface from which traffic is generated while eth0 is the
tunnel.
--------------
#Commands
echo 1 > /proc/sys/net/ipv4/ip_forward
echo 1 > /proc/sys/net/ipv4/conf/all/accept_local
echo 1 > /proc/sys/net/ipv4/conf/eth0/accept_local
echo 1 > /proc/sys/net/ipv4/conf/eth1/accept_local
ip addr add 192.168.77.2/24 dev eth0
ip link set eth0 mtu 1400
ip link set eth0 up
ip addr add 192.168.33.2/24 dev eth1
ip link set eth1 mtu 1400
ip link set eth1 up
ip ru add to 192.168.33.1 lookup 8 prio 4000
ip ru add oif eth1 lookup 8 prio 4010
ip ru add to 192.168.77.1 lookup 9 prio 4030
ip route add default dev eth1 table 8
ip route add default dev eth0 table 9
iptables -t raw -A OUTPUT -j LOG --log-prefix "RAW-OUT >> "
iptables -t mangle -A POSTROUTING -j LOG --log-prefix "MAN-PST >> "
echo 0 > /proc/sys/net/ipv4/tcp_timestamps
# out direction
ip xfrm state add src 192.168.77.2 dst 192.168.77.1 proto esp spi 0x1234
mode tunnel enc 'cbc(aes)'
0xbb31df5b207dc1c7a8512eeda0b2d0691e27bc8059dbb82df616bb9955058cd5 auth
'hmac(sha1)' 0x93b43b527d564efb9eac8cd04510b86e409f8ea7 flag af-unspec
encap espinudp 4500 4500 0.0.0.0
ip xfrm policy add dir out src 192.168.33.2 tmpl src 192.168.77.2 dst
192.168.77.1 proto esp spi 0x1234 mode tunnel
# in direction
ip xfrm state add src 192.168.77.1 dst 192.168.77.2 proto esp spi 0x4321
mode tunnel enc 'cbc(aes)'
0x5d3ca96d1af2eaa9cf8f1c1cace88f550e2a5b7b82027023287e1fe2a42f7f54 auth
'hmac(sha1)' 0xcd09f850d7c0dd6dc0ed342619c1165571452f9d flag af-unspec
encap espinudp 4500 4500 0.0.0.0
ip xfrm policy add dir in dst 192.168.33.2 tmpl src 192.168.77.1 dst
192.168.77.2 proto esp spi 0x4321 mode tunnel
ip xfrm policy add dir fwd dst 192.168.33.2 tmpl src 192.168.77.1 dst
192.168.77.2 proto esp spi 0x4321 mode tunnel
--------------
Output when resetting oif (3.18)
root@vm:~# ping -c 1 -I eth1 192.168.33.1
PING 192.168.33.1 (192.168.33.1) 56(84) bytes of data.
RAW-OUT >> IN= OUT=eth0 SRC=192.168.33.2 DST=192.168.33.1 LEN=84
TOS=0x00 PREC=0x00 TTL=64 ID=801 DF PROTO=ICMP TYPE=8 CODE=0 ID=2040 SEQ=1
MAN-PST >> IN= OUT=eth0 SRC=192.168.33.2 DST=192.168.33.1 LEN=84
TOS=0x00 PREC=0x00 TTL=64 ID=801 DF PROTO=ICMP TYPE=8 CODE=0 ID=2040 SEQ=1
RAW-OUT >> IN= OUT=eth0 SRC=192.168.77.2 DST=192.168.77.1 LEN=160
TOS=0x00 PREC=0x00 TTL=64 ID=41757 DF PROTO=UDP SPT=4500 DPT=4500 LEN=140
MAN-PST >> IN= OUT=eth0 SRC=192.168.77.2 DST=192.168.77.1 LEN=160
TOS=0x00 PREC=0x00 TTL=64 ID=41757 DF PROTO=UDP SPT=4500 DPT=4500 LEN=140
--------------
Output when preserving oif (4.4)
root@vm:~# ping -c 1 -I eth1 192.168.33.1
PING 192.168.33.1 (192.168.33.1) 56(84) bytes of data.
RAW-OUT >> IN= OUT=eth1 SRC=192.168.33.2 DST=192.168.33.1 LEN=84
TOS=0x00 PREC=0x00 TTL=64 ID=20191 DF PROTO=ICMP TYPE=8 CODE=0 ID=2043
SEQ=1
MAN-PST >> IN= OUT=eth1 SRC=192.168.33.2 DST=192.168.33.1 LEN=84
TOS=0x00 PREC=0x00 TTL=64 ID=20191 DF PROTO=ICMP TYPE=8 CODE=0 ID=2043
SEQ=1
RAW-OUT >> IN= OUT=eth1 SRC=192.168.77.2 DST=192.168.77.1 LEN=160
TOS=0x00 PREC=0x00 TTL=64 ID=49515 DF PROTO=UDP SPT=4500 DPT=4500 LEN=140
MAN-PST >> IN= OUT=eth1 SRC=192.168.77.2 DST=192.168.77.1 LEN=160
TOS=0x00 PREC=0x00 TTL=64 ID=49515 DF PROTO=UDP SPT=4500 DPT=4500 LEN=140
I can't explain the iptables output but from a FIB lookup perspective it
is using table 8 per the FIB rules, the xfrm is hit and packets shift to
192.168.77.1 and go out what you have as eth0.
Take a look at:
perf record -e fib:* -a -g
perf script
And then run tcpdump on both eth0 and eth1. For me on "eth0" (which is
really eth11 for my VM setup) I see this on the ping:
20:50:11.389837 ARP, Request who-has 192.168.77.2 tell 192.168.77.1,
length 28
20:50:11.390079 ARP, Reply 192.168.77.2 is-at 02:00:12:34:02:0a, length 28
20:50:11.390101 IP 192.168.77.1 > 192.168.77.2: ICMP 192.168.77.1 udp
port 4500 unreachable, length 168
So the packets are going out "eth0" as expected.
That said, the commands you have given do not totally transfer to
another setup. In my case I have 2 VMs with eth11 and eth12 directly
connected (VM1 eth11 <--> VM2 eth11 and ditto for eth12). You have given
one side of the commands and I have configured the other side with the
.1 addresses but not bothered to translate the xfrm commands.
That said, this seems like a contrived example -- you pin ping to device
eth1 (-I eth1), you are pinging a host on the network for eth1 but want
packets to go out eth0 via the xfrm. Can you elaborate on the real use
case and problem here?
