conf: Allow address remapped to host to be configured

Because the host and guest share the same IP address with passt/pasta, it's
not possible for the guest to directly address the host.  Therefore we
allow packets from the guest going to a special "NAT to host" address to be
redirected to the host, appearing there as though they have both source and
destination address of loopback.

Currently that special address is always the address of the default
gateway (or none).  That can be a problem if we want that gateway to be
addressable by the guest.  Therefore, allow the special "NAT to host"
address to be overridden on the command line with a new --map-host-loopback
option.

In order to exercise and test it, update the passt_in_ns and perf
tests to use this option and give different mapping addresses for the
two layers of the environment.

Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>

1 files changed, 17 insertions, 16 deletions

diff --git a/test/perf/passt_tcp b/test/perf/passt_tcp
index 635998e..089d953 100644
--- a/test/perf/passt_tcp
+++ b/test/perf/passt_tcp
@@ -15,6 +15,9 @@ gtools	/sbin/sysctl ip jq nproc seq sleep iperf3 tcp_rr tcp_crr # From neper
 nstools	/sbin/sysctl ip jq nproc seq sleep iperf3 tcp_rr tcp_crr
 htools	bc head sed seq
 
+set	MAP_NS4 192.0.2.2
+set	MAP_NS6 2001:db8:9a55::2
+
 test	passt: throughput and latency
 
 guest	/sbin/sysctl -w net.core.rmem_max=536870912
@@ -29,8 +32,6 @@ ns	/sbin/sysctl -w net.ipv4.tcp_rmem="4096 524288 134217728"
 ns	/sbin/sysctl -w net.ipv4.tcp_wmem="4096 524288 134217728"
 ns	/sbin/sysctl -w net.ipv4.tcp_timestamps=0
 
-gout	GW ip -j -4 route show|jq -rM '.[] | select(.dst == "default").gateway'
-gout	GW6 ip -j -6 route show|jq -rM '.[] | select(.dst == "default").gateway'
 gout	IFNAME ip -j link show | jq -rM '.[] | select(.link_type == "ether").ifname'
 
 hout	FREQ_PROCFS (echo "scale=1"; sed -n 's/cpu MHz.*: \([0-9]*\)\..*$/(\1+10^2\/2)\/10^3/p' /proc/cpuinfo) | bc -l | head -n1
@@ -54,16 +55,16 @@ iperf3s	ns 10002
 bw	-
 bw	-
 guest	ip link set dev __IFNAME__ mtu 1280
-iperf3	BW guest __GW6__%__IFNAME__ 10002 __TIME__ __OPTS__ -w 4M
+iperf3	BW guest __MAP_NS6__ 10002 __TIME__ __OPTS__ -w 4M
 bw	__BW__ 1.2 1.5
 guest	ip link set dev __IFNAME__ mtu 1500
-iperf3	BW guest __GW6__%__IFNAME__ 10002 __TIME__ __OPTS__ -w 4M
+iperf3	BW guest __MAP_NS6__ 10002 __TIME__ __OPTS__ -w 4M
 bw	__BW__ 1.6 1.8
 guest	ip link set dev __IFNAME__ mtu 9000
-iperf3	BW guest __GW6__%__IFNAME__ 10002 __TIME__ __OPTS__ -w 8M
+iperf3	BW guest __MAP_NS6__ 10002 __TIME__ __OPTS__ -w 8M
 bw	__BW__ 4.0 5.0
 guest	ip link set dev __IFNAME__ mtu 65520
-iperf3	BW guest __GW6__%__IFNAME__ 10002 __TIME__ __OPTS__ -w 16M
+iperf3	BW guest __MAP_NS6__ 10002 __TIME__ __OPTS__ -w 16M
 bw	__BW__ 7.0 8.0
 
 iperf3k	ns
@@ -75,7 +76,7 @@ lat	-
 lat	-
 lat	-
 nsb	tcp_rr --nolog -6
-gout	LAT tcp_rr --nolog -l1 -6 -c -H __GW6__%__IFNAME__ | sed -n 's/^throughput=\(.*\)/\1/p'
+gout	LAT tcp_rr --nolog -l1 -6 -c -H __MAP_NS6__ | sed -n 's/^throughput=\(.*\)/\1/p'
 lat	__LAT__ 200 150
 
 tl	TCP CRR latency over IPv6: guest to host
@@ -85,29 +86,29 @@ lat	-
 lat	-
 lat	-
 nsb	tcp_crr --nolog -6
-gout	LAT tcp_crr --nolog -l1 -6 -c -H __GW6__%__IFNAME__ | sed -n 's/^throughput=\(.*\)/\1/p'
+gout	LAT tcp_crr --nolog -l1 -6 -c -H __MAP_NS6__ | sed -n 's/^throughput=\(.*\)/\1/p'
 lat	__LAT__ 500 400
 
 tr	TCP throughput over IPv4: guest to host
 iperf3s	ns 10002
 
 guest	ip link set dev __IFNAME__ mtu 256
-iperf3	BW guest __GW__ 10002 __TIME__ __OPTS__ -w 1M
+iperf3	BW guest __MAP_NS4__ 10002 __TIME__ __OPTS__ -w 1M
 bw	__BW__ 0.2 0.3
 guest	ip link set dev __IFNAME__ mtu 576
-iperf3	BW guest __GW__ 10002 __TIME__ __OPTS__ -w 1M
+iperf3	BW guest __MAP_NS4__ 10002 __TIME__ __OPTS__ -w 1M
 bw	__BW__ 0.5 0.8
 guest	ip link set dev __IFNAME__ mtu 1280
-iperf3	BW guest __GW__ 10002 __TIME__ __OPTS__ -w 4M
+iperf3	BW guest __MAP_NS4__ 10002 __TIME__ __OPTS__ -w 4M
 bw	__BW__ 1.2 1.5
 guest	ip link set dev __IFNAME__ mtu 1500
-iperf3	BW guest __GW__ 10002 __TIME__ __OPTS__ -w 4M
+iperf3	BW guest __MAP_NS4__ 10002 __TIME__ __OPTS__ -w 4M
 bw	__BW__ 1.6 1.8
 guest	ip link set dev __IFNAME__ mtu 9000
-iperf3	BW guest __GW__ 10002 __TIME__ __OPTS__ -w 8M
+iperf3	BW guest __MAP_NS4__ 10002 __TIME__ __OPTS__ -w 8M
 bw	__BW__ 4.0 5.0
 guest	ip link set dev __IFNAME__ mtu 65520
-iperf3	BW guest __GW__ 10002 __TIME__ __OPTS__ -w 16M
+iperf3	BW guest __MAP_NS4__ 10002 __TIME__ __OPTS__ -w 16M
 bw	__BW__ 7.0 8.0
 
 iperf3k	ns
@@ -123,7 +124,7 @@ lat	-
 lat	-
 lat	-
 nsb	tcp_rr --nolog -4
-gout	LAT tcp_rr --nolog -l1 -4 -c -H __GW__ | sed -n 's/^throughput=\(.*\)/\1/p'
+gout	LAT tcp_rr --nolog -l1 -4 -c -H __MAP_NS4__ | sed -n 's/^throughput=\(.*\)/\1/p'
 lat	__LAT__ 200 150
 
 tl	TCP CRR latency over IPv4: guest to host
@@ -133,7 +134,7 @@ lat	-
 lat	-
 lat	-
 nsb	tcp_crr --nolog -4
-gout	LAT tcp_crr --nolog -l1 -4 -c -H __GW__ | sed -n 's/^throughput=\(.*\)/\1/p'
+gout	LAT tcp_crr --nolog -l1 -4 -c -H __MAP_NS4__ | sed -n 's/^throughput=\(.*\)/\1/p'
 lat	__LAT__ 500 400
 
 tr	TCP throughput over IPv6: host to guest