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>

3 files changed, 103 insertions, 30 deletions

diff --git a/test/passt_in_ns/dhcp b/test/passt_in_ns/dhcp
new file mode 100644
index 0000000..0ceed7c
--- /dev/null
+++ b/test/passt_in_ns/dhcp
@@ -0,0 +1,73 @@
+# SPDX-License-Identifier: GPL-2.0-or-later
+#
+# PASST - Plug A Simple Socket Transport
+#  for qemu/UNIX domain socket mode
+#
+# PASTA - Pack A Subtle Tap Abstraction
+#  for network namespace/tap device mode
+#
+# test/passt/dhcp - Check DHCP and DHCPv6 functionality in passt mode
+#
+# Copyright (c) 2021 Red Hat GmbH
+# Author: Stefano Brivio <sbrivio@redhat.com>
+
+gtools	ip jq dhclient sed tr
+htools	ip jq sed tr head
+
+set	MAP_NS4 192.0.2.2
+set	MAP_NS6 2001:db8:9a55::2
+
+test	Interface name
+gout	IFNAME ip -j link show | jq -rM '.[] | select(.link_type == "ether").ifname'
+hout	HOST_IFNAME ip -j -4 route show|jq -rM '[.[] | select(.dst == "default").dev] | .[0]'
+hout	HOST_IFNAME6 ip -j -6 route show|jq -rM '[.[] | select(.dst == "default").dev] | .[0]'
+check	[ -n "__IFNAME__" ]
+
+test	DHCP: address
+guest	/sbin/dhclient -4 __IFNAME__
+gout	ADDR ip -j -4 addr show|jq -rM '.[] | select(.ifname == "__IFNAME__").addr_info[0].local'
+hout	HOST_ADDR ip -j -4 addr show|jq -rM '.[] | select(.ifname == "__HOST_IFNAME__").addr_info[0].local'
+check	[ "__ADDR__" = "__HOST_ADDR__" ]
+
+test	DHCP: route
+gout	GW ip -j -4 route show|jq -rM '.[] | select(.dst == "default").gateway'
+hout	HOST_GW ip -j -4 route show|jq -rM '[.[] | select(.dst == "default").gateway] | .[0]'
+check	[ "__GW__" = "__HOST_GW__" ]
+
+test	DHCP: MTU
+gout	MTU ip -j link show | jq -rM '.[] | select(.ifname == "__IFNAME__").mtu'
+check	[ __MTU__ = 65520 ]
+
+test	DHCP: DNS
+gout	DNS sed -n 's/^nameserver \([0-9]*\.\)\(.*\)/\1\2/p' /etc/resolv.conf | tr '\n' ',' | sed 's/,$//;s/$/\n/'
+hout	HOST_DNS sed -n 's/^nameserver \([0-9]*\.\)\(.*\)/\1\2/p' /etc/resolv.conf | head -n3 | tr '\n' ',' | sed 's/,$//;s/$/\n/'
+check	[ "__DNS__" = "__HOST_DNS__" ] || ( [ "__DNS__" = "__MAP_NS4__" ] && expr "__HOST_DNS__" : "127[.]" )
+
+# FQDNs should be terminated by dots, but the guest DHCP client might omit them:
+# strip them first
+test	DHCP: search list
+gout	SEARCH sed 's/\. / /g' /etc/resolv.conf | sed 's/\.$//g' | sed -n 's/^search \(.*\)/\1/p' | tr ' \n' ',' | sed 's/,$//;s/$/\n/'
+hout	HOST_SEARCH sed 's/\. / /g' /etc/resolv.conf | sed 's/\.$//g' | sed -n 's/^search \(.*\)/\1/p' | tr ' \n' ',' | sed 's/,$//;s/$/\n/'
+check	[ "__SEARCH__" = "__HOST_SEARCH__" ]
+
+test	DHCPv6: address
+guest	/sbin/dhclient -6 __IFNAME__
+gout	ADDR6 ip -j -6 addr show|jq -rM '[.[] | select(.ifname == "__IFNAME__").addr_info[] | select(.prefixlen == 128).local] | .[0]'
+hout	HOST_ADDR6 ip -j -6 addr show|jq -rM '[.[] | select(.ifname == "__HOST_IFNAME6__").addr_info[] | select(.scope == "global" and .deprecated != true).local] | .[0]'
+check	[ "__ADDR6__" = "__HOST_ADDR6__" ]
+
+test	DHCPv6: route
+gout	GW6 ip -j -6 route show|jq -rM '.[] | select(.dst == "default").gateway'
+hout	HOST_GW6 ip -j -6 route show|jq -rM '[.[] | select(.dst == "default").gateway] | .[0]'
+check	[ "__GW6__" = "__HOST_GW6__" ]
+
+# Strip interface specifier: interface names might differ between host and guest
+test	DHCPv6: DNS
+gout	DNS6 sed -n 's/^nameserver \([^:]*:\)\([^%]*\).*/\1\2/p' /etc/resolv.conf | tr '\n' ',' | sed 's/,$//;s/$/\n/'
+hout	HOST_DNS6 sed -n 's/^nameserver \([^:]*:\)\([^%]*\).*/\1\2/p' /etc/resolv.conf | tr '\n' ',' | sed 's/,$//;s/$/\n/'
+check	[ "__DNS6__" = "__HOST_DNS6__" ] || [ "__DNS6__" = "__MAP_NS6__" -a "__HOST_DNS6__" = "::1" ]
+
+test	DHCPv6: search list
+gout	SEARCH6 sed 's/\. / /g' /etc/resolv.conf | sed 's/\.$//g' | sed -n 's/^search \(.*\)/\1/p' | tr ' \n' ',' | sed 's/,$//;s/$/\n/'
+hout	HOST_SEARCH6 sed 's/\. / /g' /etc/resolv.conf | sed 's/\.$//g' | sed -n 's/^search \(.*\)/\1/p' | tr ' \n' ',' | sed 's/,$//;s/$/\n/'
+check	[ "__SEARCH6__" = "__HOST_SEARCH6__" ]
diff --git a/test/passt_in_ns/tcp b/test/passt_in_ns/tcp
index cdb7060..aaf340e 100644
--- a/test/passt_in_ns/tcp
+++ b/test/passt_in_ns/tcp
@@ -15,6 +15,11 @@ gtools	socat ip jq
 htools	socat ip jq
 nstools	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_BIG __STATEDIR__/test_big.bin
 set	TEMP_SMALL __STATEDIR__/test_small.bin
 set	TEMP_NS_BIG __STATEDIR__/test_ns_big.bin
@@ -36,16 +41,15 @@ check	cmp __TEMP_NS_BIG__ __BASEPATH__/big.bin
 
 test	TCP/IPv4: guest to host: big transfer
 hostb	socat -u TCP4-LISTEN:10003 OPEN:__TEMP_BIG__,create,trunc
-gout	GW ip -j -4 route show|jq -rM '.[] | select(.dst == "default").gateway'
 sleep	1
-guest	socat -u OPEN:/root/big.bin TCP4:__GW__:10003
+guest	socat -u OPEN:/root/big.bin TCP4:__MAP_HOST4__:10003
 hostw
 check	cmp __TEMP_BIG__ __BASEPATH__/big.bin
 
 test	TCP/IPv4: guest to ns: big transfer
 nsb	socat -u TCP4-LISTEN:10002 OPEN:__TEMP_NS_BIG__,create,trunc
 sleep	1
-guest	socat -u OPEN:/root/big.bin TCP4:__GW__:10002
+guest	socat -u OPEN:/root/big.bin TCP4:__MAP_NS4__:10002
 nsw
 check	cmp __TEMP_NS_BIG__ __BASEPATH__/big.bin
 
@@ -59,7 +63,7 @@ check	cmp __TEMP_BIG__ __BASEPATH__/big.bin
 test	TCP/IPv4: ns to host (via tap): big transfer
 hostb	socat -u TCP4-LISTEN:10003 OPEN:__TEMP_BIG__,create,trunc
 sleep	1
-ns	socat -u OPEN:__BASEPATH__/big.bin TCP4:__GW__:10003
+ns	socat -u OPEN:__BASEPATH__/big.bin TCP4:__MAP_HOST4__:10003
 hostw
 check	cmp __TEMP_BIG__ __BASEPATH__/big.bin
 
@@ -95,16 +99,15 @@ check	cmp __TEMP_NS_SMALL__ __BASEPATH__/small.bin
 
 test	TCP/IPv4: guest to host: small transfer
 hostb	socat -u TCP4-LISTEN:10003 OPEN:__TEMP_SMALL__,create,trunc
-gout	GW ip -j -4 route show|jq -rM '.[] | select(.dst == "default").gateway'
 sleep	1
-guest	socat -u OPEN:/root/small.bin TCP4:__GW__:10003
+guest	socat -u OPEN:/root/small.bin TCP4:__MAP_HOST4__:10003
 hostw
 check	cmp __TEMP_SMALL__ __BASEPATH__/small.bin
 
 test	TCP/IPv4: guest to ns: small transfer
 nsb	socat -u TCP4-LISTEN:10002 OPEN:__TEMP_NS_SMALL__,create,trunc
 sleep	1
-guest	socat -u OPEN:/root/small.bin TCP4:__GW__:10002
+guest	socat -u OPEN:/root/small.bin TCP4:__MAP_NS4__:10002
 nsw
 check	cmp __TEMP_NS_SMALL__ __BASEPATH__/small.bin
 
@@ -118,7 +121,7 @@ check	cmp __TEMP_SMALL__ __BASEPATH__/small.bin
 test	TCP/IPv4: ns to host (via tap): small transfer
 hostb	socat -u TCP4-LISTEN:10003 OPEN:__TEMP_SMALL__,create,trunc
 sleep	1
-ns	socat -u OPEN:__BASEPATH__/small.bin TCP4:__GW__:10003
+ns	socat -u OPEN:__BASEPATH__/small.bin TCP4:__MAP_HOST4__:10003
 hostw
 check	cmp __TEMP_SMALL__ __BASEPATH__/small.bin
 
@@ -152,17 +155,15 @@ check	cmp __TEMP_NS_BIG__ __BASEPATH__/big.bin
 
 test	TCP/IPv6: guest to host: big transfer
 hostb	socat -u TCP6-LISTEN:10003 OPEN:__TEMP_BIG__,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/big.bin TCP6:[__GW6__%__IFNAME__]:10003
+guest	socat -u OPEN:/root/big.bin TCP6:[__MAP_HOST6__]:10003
 hostw
 check	cmp __TEMP_BIG__ __BASEPATH__/big.bin
 
 test	TCP/IPv6: guest to ns: big transfer
 nsb	socat -u TCP6-LISTEN:10002 OPEN:__TEMP_NS_BIG__,create,trunc
 sleep	1
-guest	socat -u OPEN:/root/big.bin TCP6:[__GW6__%__IFNAME__]:10002
+guest	socat -u OPEN:/root/big.bin TCP6:[__MAP_NS6__]:10002
 nsw
 check	cmp __TEMP_NS_BIG__ __BASEPATH__/big.bin
 
@@ -175,9 +176,8 @@ check	cmp __TEMP_BIG__ __BASEPATH__/big.bin
 
 test	TCP/IPv6: ns to host (via tap): big transfer
 hostb	socat -u TCP6-LISTEN:10003 OPEN:__TEMP_BIG__,create,trunc
-nsout	IFNAME ip -j link show | jq -rM '.[] | select(.link_type == "ether").ifname'
 sleep	1
-ns	socat -u OPEN:__BASEPATH__/big.bin TCP6:[__GW6__%__IFNAME__]:10003
+ns	socat -u OPEN:__BASEPATH__/big.bin TCP6:[__MAP_HOST6__]:10003
 hostw
 check	cmp __TEMP_BIG__ __BASEPATH__/big.bin
 
@@ -190,6 +190,7 @@ guest	cmp test_big.bin /root/big.bin
 
 test	TCP/IPv6: ns to guest (using namespace address): big transfer
 guestb	socat -u TCP6-LISTEN:10001 OPEN:test_big.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__/big.bin TCP6:[__ADDR6__]:10001
@@ -212,17 +213,15 @@ check	cmp __TEMP_NS_SMALL__ __BASEPATH__/small.bin
 
 test	TCP/IPv6: guest to host: small transfer
 hostb	socat -u TCP6-LISTEN:10003 OPEN:__TEMP_SMALL__,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/small.bin TCP6:[__GW6__%__IFNAME__]:10003
+guest	socat -u OPEN:/root/small.bin TCP6:[__MAP_HOST6__]:10003
 hostw
 check	cmp __TEMP_SMALL__ __BASEPATH__/small.bin
 
 test	TCP/IPv6: guest to ns: small transfer
 nsb	socat -u TCP6-LISTEN:10002 OPEN:__TEMP_NS_SMALL__
 sleep	1
-guest	socat -u OPEN:/root/small.bin TCP6:[__GW6__%__IFNAME__]:10002
+guest	socat -u OPEN:/root/small.bin TCP6:[__MAP_NS6__]:10002
 nsw
 check	cmp __TEMP_NS_SMALL__ __BASEPATH__/small.bin
 
@@ -235,9 +234,8 @@ check	cmp __TEMP_SMALL__ __BASEPATH__/small.bin
 
 test	TCP/IPv6: ns to host (via tap): small transfer
 hostb	socat -u TCP6-LISTEN:10003 OPEN:__TEMP_SMALL__,create,trunc
-nsout	IFNAME ip -j link show | jq -rM '.[] | select(.link_type == "ether").ifname'
 sleep	1
-ns	socat -u OPEN:__BASEPATH__/small.bin TCP6:[__GW6__%__IFNAME__]:10003
+ns	socat -u OPEN:__BASEPATH__/small.bin TCP6:[__MAP_HOST6__]:10003
 hostw
 check	cmp __TEMP_SMALL__ __BASEPATH__/small.bin
 
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