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, 12 insertions, 10 deletions

diff --git a/test/passt_in_ns/udp b/test/passt_in_ns/udp
index 8a02513..3426ab9 100644
--- a/test/passt_in_ns/udp
+++ b/test/passt_in_ns/udp
@@ -15,6 +15,11 @@ gtools	socat ip jq
 nstools	socat ip jq
 htools	socat ip jq
 
+set	MAP_HOST4 192.0.2.1
+set	MAP_HOST6 2001:db8:9a55::1
+set	MAP_NS4 192.0.2.2
+set	MAP_NS6 2001:db8:9a55::2
+
 set	TEMP __STATEDIR__/test.bin
 set	TEMP_NS __STATEDIR__/test_ns.bin
 
@@ -34,16 +39,15 @@ check	cmp __TEMP_NS__ __BASEPATH__/medium.bin
 
 test	UDP/IPv4: guest to host
 hostb	socat -u UDP4-LISTEN:10003,null-eof OPEN:__TEMP__,create,trunc
-gout	GW ip -j -4 route show|jq -rM '.[] | select(.dst == "default").gateway'
 sleep	1
-guest	socat -u OPEN:/root/medium.bin UDP4:__GW__:10003,shut-null
+guest	socat -u OPEN:/root/medium.bin UDP4:__MAP_HOST4__:10003,shut-null
 hostw
 check	cmp __TEMP__ __BASEPATH__/medium.bin
 
 test	UDP/IPv4: guest to ns
 nsb	socat -u UDP4-LISTEN:10002,null-eof OPEN:__TEMP_NS__,create,trunc
 sleep	1
-guest	socat -u OPEN:/root/medium.bin UDP4:__GW__:10002,shut-null
+guest	socat -u OPEN:/root/medium.bin UDP4:__MAP_NS4__:10002,shut-null
 nsw
 check	cmp __TEMP_NS__ __BASEPATH__/medium.bin
 
@@ -57,7 +61,7 @@ check	cmp __TEMP__ __BASEPATH__/medium.bin
 test	UDP/IPv4: ns to host (via tap)
 hostb	socat -u UDP4-LISTEN:10003,null-eof OPEN:__TEMP__,create,trunc
 sleep	1
-ns	socat -u OPEN:__BASEPATH__/medium.bin UDP4:__GW__:10003,shut-null
+ns	socat -u OPEN:__BASEPATH__/medium.bin UDP4:__MAP_HOST4__:10003,shut-null
 hostw
 check	cmp __TEMP__ __BASEPATH__/medium.bin
 
@@ -93,17 +97,15 @@ check	cmp __TEMP_NS__ __BASEPATH__/medium.bin
 
 test	UDP/IPv6: guest to host
 hostb	socat -u UDP6-LISTEN:10003,null-eof OPEN:__TEMP__,create,trunc
-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'
 sleep	1
-guest	socat -u OPEN:/root/medium.bin UDP6:[__GW6__%__IFNAME__]:10003,shut-null
+guest	socat -u OPEN:/root/medium.bin UDP6:[__MAP_HOST6__]:10003,shut-null
 hostw
 check	cmp __TEMP__ __BASEPATH__/medium.bin
 
 test	UDP/IPv6: guest to ns
 nsb	socat -u UDP6-LISTEN:10002,null-eof OPEN:__TEMP_NS__,create,trunc
 sleep	1
-guest	socat -u OPEN:/root/medium.bin UDP6:[__GW6__%__IFNAME__]:10002,shut-null
+guest	socat -u OPEN:/root/medium.bin UDP6:[__MAP_NS6__]:10002,shut-null
 nsw
 check	cmp __TEMP_NS__ __BASEPATH__/medium.bin
 
@@ -116,9 +118,8 @@ check	cmp __TEMP__ __BASEPATH__/medium.bin
 
 test	UDP/IPv6: ns to host (via tap)
 hostb	socat -u UDP6-LISTEN:10003,null-eof OPEN:__TEMP__,create,trunc
-nsout	IFNAME ip -j link show | jq -rM '.[] | select(.link_type == "ether").ifname'
 sleep	1
-ns	socat -u OPEN:__BASEPATH__/medium.bin UDP6:[__GW6__%__IFNAME__]:10003,shut-null
+ns	socat -u OPEN:__BASEPATH__/medium.bin UDP6:[__MAP_HOST6__]:10003,shut-null
 hostw
 check	cmp __TEMP__ __BASEPATH__/medium.bin
 
@@ -131,6 +132,7 @@ guest	cmp test.bin /root/medium.bin
 
 test	UDP/IPv6: ns to guest (using namespace address)
 guestb	socat -u UDP6-LISTEN:10001,null-eof OPEN:test.bin,create,trunc
+nsout	IFNAME ip -j link show | jq -rM '.[] | select(.link_type == "ether").ifname'
 nsout	ADDR6 ip -j -6 addr show|jq -rM '.[] | select(.ifname == "__IFNAME__").addr_info[0].local'
 sleep	1
 ns	socat -u OPEN:__BASEPATH__/medium.bin UDP6:[__ADDR6__]:10001,shut-null