passt: Add support for multiple instances in different network namespaces

...sharing the same filesystem. Instead of a fixed path for the UNIX
domain socket, passt now uses a path with a counter, probing for
existing instances, and picking the first free one.

The demo script is updated accordingly -- it can now be started several
times to create multiple namespaces with an instance of passt each,
with addressing reflecting separate subnets, and NDP proxying between
them.

Signed-off-by: Stefano Brivio <sbrivio@redhat.com>

1 files changed, 57 insertions, 27 deletions

diff --git a/doc/demo.sh b/doc/demo.sh
index 5aed7f0..c7d2eac 100755
--- a/doc/demo.sh
+++ b/doc/demo.sh
@@ -30,7 +30,7 @@ ipv6_mangle() {
 		if [ ${__c} -lt 7 ]; then
 			printf "${__16b}:"
 		else
-			printf "abcd\n" && break
+			printf "%04x\n" $((0xabc0 + ${2})) && break
 		fi
 		__c=$((__c + 1))
 	done
@@ -40,43 +40,66 @@ ipv6_mangle() {
 ndp_setup() {
 	sysctl -w net.ipv6.conf.all.proxy_ndp=1
 	ip -6 neigh add proxy "${1}" dev "$(ipv6_dev)"
+
+	for i in `seq 1 63`; do
+		__neigh="$(ipv6_mangle ${1} ${i})"
+		if [ "${__neigh}" != "${1}" ]; then
+			ip -6 neigh add proxy "${__neigh}" dev "${2}"
+		fi
+	done
 }
 
-ip netns del passt 2>/dev/null || :
-ip link del veth_passt 2>/dev/null || :
-ip netns add passt
-ip link add veth_passt up netns passt type veth peer name veth_passt
-ip link set dev veth_passt up
-ip -n passt link set dev lo up
+ns_idx=0
+for i in `seq 1 63`; do
+	ns="passt_${i}"
+	ns_idx=${i}
+
+	busy=0
+	for p in $(pidof passt); do
+		[ "$(ip netns identify ${p})" = "${ns}" ] && busy=1 && break
+	done
+	[ ${busy} -eq 0 ] && break
+done
+
+[ ${busy} -ne 0 ] && echo "Couldn't create namespace" && exit 1
+
+ip netns del "${ns}" 2>/dev/null || :
+ip netns add "${ns}"
+ip link del "veth_${ns}" 2>/dev/null || :
+ip link add "veth_${ns}" up netns "${ns}" type veth peer name "veth_${ns}"
+ip link set dev "veth_${ns}" up
+ip -n "${ns}" link set dev lo up
 
+ipv4_main="192.0.2.$(((ns_idx - 1) * 4 + 1))"
+ipv4_ns="192.0.2.$(((ns_idx - 1) * 4 + 2))"
 
-ip -n passt addr add 192.0.2.2/24 dev veth_passt
-ip addr add 192.0.2.1/24 dev veth_passt
-ip -n passt route add default via 192.0.2.1
+ip -n "${ns}" addr add "${ipv4_ns}/30" dev "veth_${ns}"
+ip addr add "${ipv4_main}/30" dev "veth_${ns}"
+ip -n "${ns}" route add default via "${ipv4_main}"
 
 sysctl -w net.ipv4.ip_forward=1
-nft delete table passt_nat 2>/dev/null || :
-nft add table passt_nat
-nft 'add chain passt_nat postrouting { type nat hook postrouting priority -100 ; }'
-nft add rule passt_nat postrouting ip saddr 192.0.2.2 masquerade
+nft delete table "${ns}_nat" 2>/dev/null || :
+nft add table "${ns}_nat"
+nft add chain "${ns}_nat" postrouting '{ type nat hook postrouting priority -100 ; }'
+nft add rule "${ns}_nat" postrouting ip saddr "${ipv4_ns}" masquerade
 
 ipv6_addr="$(ipv6_devaddr "$(ipv6_dev)")"
-ipv6_passt="$(ipv6_mangle "${ipv6_addr}")"
-ndp_setup "${ipv6_passt}"
-ip -n passt addr add "${ipv6_passt}/$(ipv6_mask "${ipv6_addr}")" dev veth_passt
-ip addr add "${ipv6_addr}" dev veth_passt
-ip route add "${ipv6_passt}" dev veth_passt
-passt_ll="$(ipv6_ll_addr "veth_passt")"
-main_ll="$(get_token "link/ether" $(ip -o li sh veth_passt))"
-ip neigh add "${passt_ll%%/*}" dev veth_passt lladdr "${main_ll}"
-ip -n passt route add default via "${passt_ll%%/*}" dev veth_passt
+ipv6_passt="$(ipv6_mangle "${ipv6_addr}" ${ns_idx})"
+ndp_setup "${ipv6_passt}" "veth_${ns}"
+ip -n "${ns}" addr add "${ipv6_passt}/$(ipv6_mask "${ipv6_addr}")" dev "veth_${ns}"
+ip addr add "${ipv6_addr}" dev "veth_${ns}"
+ip route add "${ipv6_passt}" dev "veth_${ns}"
+passt_ll="$(ipv6_ll_addr "veth_${ns}")"
+main_ll="$(get_token "link/ether" $(ip -o li sh "veth_${ns}"))"
+ip neigh add "${passt_ll%%/*}" dev "veth_${ns}" lladdr "${main_ll}"
+ip -n "${ns}" route add default via "${passt_ll%%/*}" dev "veth_${ns}"
 
 sysctl -w net.ipv6.conf.all.forwarding=1
 
 
-ethtool -K veth_passt tx off
-ip netns exec passt ethtool -K veth_passt tx off
-ip netns exec passt sysctl -w net.ipv4.ping_group_range="0 2147483647"
+ethtool -K "veth_${ns}" tx off
+ip netns exec "${ns}" ethtool -K "veth_${ns}" tx off
+ip netns exec "${ns}" sysctl -w net.ipv4.ping_group_range="0 2147483647"
 
 
 sysctl -w net.core.rmem_max=16777216
@@ -84,5 +107,12 @@ sysctl -w net.core.wmem_max=16777216
 sysctl -w net.core.rmem_default=16777216
 sysctl -w net.core.wmem_default=16777216
 
+echo
+echo "Namespace ${ns} set up, addresses:"
+echo "    ${ipv4_ns}"
+echo "    ${ipv6_passt}"
+echo
+echo "Starting passt..."
+echo
 
-ip netns exec passt ./passt
+ip netns exec "${ns}" ./passt