Hello VPP experts,
I'm trying to use GRE tunnelling inside Microsft Azure but I'm having some
troubles in making it work.
Please, attached you can find the configuration I have inside Azure. What I
would like to do is to send packets from VM1 to VM4, passing through the two
VMs in the middle, in which VPP is deployed. Between VM2 and VM3 I would like
to deploy a GRE tunnel.
More in details, the packets should go from Eth1 of VM1 to eth1 of VM2. Here
the packets are passed to eth2 and using a GRE tunnel, the packets should reach
eth2 of VM3.
Note that inside VM2 and VM3 I have deployed VPP and both the nic eth1 and eth2
are controlled by VPP
For now, what I have is that the packets are correctly processed by VPP but
they get lost between the link VM2 and VM3.
To setup GRE and ip routes, inside the VPP CLI I typed these commands:
create gre tunnel src 10.0.20.4 dst 10.0.20.5 // to create the GRE tunnel
between eth2 of VM2 and eth2 of VM3
set int state gre0 up
ip route add 10.0.30.0/24 via gre0 // to route all the packets that have to
go towards VM4 via the gre interface
If I do a trace add dpdk-input and show trace I obtain the following trace:
01:50:51:710865: dpdk-input
FailsafeEthernet2 rx queue 0
buffer 0x293aa: current data 14, length 84, free-list 0, clone-count 0,
totlen-nifb 0, trace 0x0
ext-hdr-valid
l4-cksum-computed l4-cksum-correct l2-hdr-offset 0
PKT MBUF: port 3, nb_segs 1, pkt_len 98
buf_len 2176, data_len 98, ol_flags 0x0, data_off 128, phys_addr 0x18e4eb00
packet_type 0x11 l2_len 0 l3_len 0 outer_l2_len 0 outer_l3_len 0
rss 0x0 fdir.hi 0x0 fdir.lo 0x0
Packet Types
RTE_PTYPE_L2_ETHER (0x0001) Ethernet packet
RTE_PTYPE_L3_IPV4 (0x0010) IPv4 packet without extension headers
IP4: a0:3d:6f:00:c1:8f -> 00:0d:3a:95:04:ae
ICMP: 10.0.10.5 -> 10.0.30.5
tos 0x00, ttl 64, length 84, checksum 0xae35
fragment id 0x506a, flags DONT_FRAGMENT
ICMP echo_request checksum 0x19f2
01:50:51:710897: ip4-input
ICMP: 10.0.10.5 -> 10.0.30.5
tos 0x00, ttl 64, length 84, checksum 0xae35
fragment id 0x506a, flags DONT_FRAGMENT
ICMP echo_request checksum 0x19f2
01:50:51:710902: ip4-lookup
fib 0 dpo-idx 4 flow hash: 0x00000000
ICMP: 10.0.10.5 -> 10.0.30.5
tos 0x00, ttl 64, length 84, checksum 0xae35
fragment id 0x506a, flags DONT_FRAGMENT
ICMP echo_request checksum 0x19f2
01:50:51:710904: ip4-midchain
GRE: 10.0.20.4 -> 10.0.20.5
tos 0x00, ttl 254, length 108, checksum 0x805a
fragment id 0x0000
GRE ip4
01:50:51:710907: adj-midchain-tx
adj-midchain:[4]:ipv4 via 0.0.0.0 gre0: mtu:9000
4500000000000000fe2f80c60a0014040a00140500000800
stacked-on:
[@3]: ipv4 via 10.0.20.5 FailsafeEthernet4: mtu:9000
123456789abc000d3a9514d90800
01:50:51:710908: ip4-rewrite
tx_sw_if_index 2 dpo-idx 2 : ipv4 via 10.0.20.5 FailsafeEthernet4: mtu:9000
123456789abc000d3a9514d90800 flow hash: 0x00000000
00000000: 123456789abc000d3a9514d908004500006c00000000fd2f815a0a0014040a00
00000020: 14050000080045000054506a40003f01af350a000a050a001e050800
01:50:51:710910: FailsafeEthernet4-output
FailsafeEthernet4
IP4: 00:0d:3a:95:14:d9 -> 12:34:56:78:9a:bc
GRE: 10.0.20.4 -> 10.0.20.5
tos 0x00, ttl 253, length 108, checksum 0x815a
fragment id 0x0000
GRE ip4
01:50:51:710911: FailsafeEthernet4-tx
FailsafeEthernet4 tx queue 0
buffer 0x293aa: current data -24, length 122, free-list 0, clone-count 0,
totlen-nifb 0, trace 0x0
ext-hdr-valid
l4-cksum-computed l4-cksum-correct l2-hdr-offset 0
PKT MBUF: port 3, nb_segs 1, pkt_len 122
buf_len 2176, data_len 122, ol_flags 0x0, data_off 104, phys_addr 0x18e4eb00
packet_type 0x11 l2_len 0 l3_len 0 outer_l2_len 0 outer_l3_len 0
rss 0x0 fdir.hi 0x0 fdir.lo 0x0
Packet Types
RTE_PTYPE_L2_ETHER (0x0001) Ethernet packet
RTE_PTYPE_L3_IPV4 (0x0010) IPv4 packet without extension headers
IP4: 00:0d:3a:95:14:d9 -> 12:34:56:78:9a:bc
GRE: 10.0.20.4 -> 10.0.20.5
tos 0x00, ttl 253, length 108, checksum 0x815a
fragment id 0x0000
GRE ip4
the part that I don't understand and maybe could be an issue on why GRE is not
working is this one:
01:50:51:710910: FailsafeEthernet4-output
FailsafeEthernet4
IP4: 00:0d:3a:95:14:d9 -> 12:34:56:78:9a:bc
GRE: 10.0.20.4 -> 10.0.20.5
tos 0x00, ttl 253, length 108, checksum 0x815a
fragment id 0x0000
GRE ip4
where there is a MAC address which does not belong to any nic of the VMs:
12:34:56:78:9a:bc
Could you help me to highlight what I'm missing in my configuration? Perhaps
I'm missing some route tables?
Thanks in advance for your answers,
Francesco
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