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=== Description (from pull-request) ===
From 1f9752260266a8c1b8ed02014284c6a5b792cae4 Mon Sep 17 00:00:00 2001
From: Thomas Hipp <thomas.h...@canonical.com>
Date: Mon, 9 Jul 2018 15:03:49 +0200
Subject: [PATCH 1/2] lxd: Optimized UDP/TCP proxying (NAT)
Signed-off-by: Thomas Hipp <thomas.h...@canonical.com>
---
lxd/container_lxc.go | 101 ++++++++++++++++++++++++++++++
lxd/{networks_iptables.go => iptables.go} | 35 +++++++++--
2 files changed, 130 insertions(+), 6 deletions(-)
rename lxd/{networks_iptables.go => iptables.go} (62%)
diff --git a/lxd/container_lxc.go b/lxd/container_lxc.go
index 2cee8ad1d..afad5b06d 100644
--- a/lxd/container_lxc.go
+++ b/lxd/container_lxc.go
@@ -6850,6 +6850,10 @@ func (c *containerLXC) insertProxyDevice(devName string,
m types.Device) error {
return fmt.Errorf("Can't add proxy device to stopped container")
}
+ if c.tryNat(devName, m) {
+ return nil
+ }
+
proxyValues, err := setupProxyProcInfo(c, m)
if err != nil {
return err
@@ -6881,13 +6885,107 @@ func (c *containerLXC) insertProxyDevice(devName
string, m types.Device) error {
return nil
}
+func (c *containerLXC) tryNat(proxy string, device types.Device) bool {
+ listenAddr, err := parseAddr(device["listen"])
+ if err != nil {
+ return false
+ }
+
+ connectAddr, err := parseAddr(device["connect"])
+ if err != nil {
+ return false
+ }
+
+ cAddrFields := strings.SplitN(connectAddr.addr[0], ":", 2)
+ validIP := false
+
+ for _, name := range c.expandedDevices.DeviceNames() {
+ m := c.expandedDevices[name]
+ if m["type"] == "nic" {
+ if m["nictype"] != "bridged" {
+ continue
+ }
+
+ // Check whether the NIC has a static IP
+ ip, ok := m["ipv4.address"]
+ if ok && ip == cAddrFields[0] {
+ validIP = true
+ break
+ }
+ }
+ }
+
+ if !validIP {
+ logger.Info("NAT unavailable: NIC IP doesn't match proxy target
IP")
+ return false
+ }
+
+ if len(connectAddr.addr) > len(listenAddr.addr) {
+ // Cannot support single port -> multiple port
+ return false
+ }
+
+ // Support TCP <-> TCP and UDP <-> UDP
+ if listenAddr.connType == "unix" || connectAddr.connType == "unix" ||
+ listenAddr.connType != connectAddr.connType {
+ logger.Info(fmt.Sprintf("NAT unavailable: %s <-> %s not
supported",
+ listenAddr.connType, connectAddr.connType))
+ return false
+ }
+
+ iptablesComment := fmt.Sprintf("%s (%s)", c.Name(), proxy)
+
+ for i, lAddr := range listenAddr.addr {
+ listenFields := strings.SplitN(lAddr, ":", 2)
+ var cAddr string
+ if len(connectAddr.addr) == 1 {
+ cAddr = connectAddr.addr[0]
+ } else {
+ cAddr = connectAddr.addr[i]
+ }
+
+ // outbound <-> container
+ err := containerIptablesPrepend("ipv4", iptablesComment, "nat",
+ "PREROUTING", "-p", listenAddr.connType,
"--destination",
+ listenFields[0], "--dport", listenFields[1], "-j",
"DNAT",
+ "--to-destination", cAddr)
+ if err != nil {
+ goto fail
+ }
+
+ // host <-> container
+ err = containerIptablesPrepend("ipv4", iptablesComment, "nat",
+ "OUTPUT", "-p", listenAddr.connType, "--destination",
+ listenFields[0], "--dport", listenFields[1], "-j",
"DNAT",
+ "--to-destination", cAddr)
+ if err != nil {
+ goto fail
+ }
+ }
+
+ logger.Info("Using NAT for proxy device '%s'", proxy)
+ return true
+
+fail:
+ containerIptablesClear("ipv4", iptablesComment, "nat")
+ return false
+}
+
func (c *containerLXC) removeProxyDevice(devName string) error {
if !c.IsRunning() {
return fmt.Errorf("Can't remove proxy device from stopped
container")
}
+ // Remove possible iptables entries
+ containerIptablesClear("ipv4", fmt.Sprintf("%s (%s)", c.Name(),
devName), "nat")
+
devFileName := fmt.Sprintf("proxy.%s", devName)
devPath := filepath.Join(c.DevicesPath(), devFileName)
+ if !shared.PathExists(devPath) {
+ // There's no proxy process if NAT is enabled
+ return nil
+ }
+
err := killProxyProc(devPath)
if err != nil {
return err
@@ -6897,6 +6995,9 @@ func (c *containerLXC) removeProxyDevice(devName string)
error {
}
func (c *containerLXC) removeProxyDevices() error {
+ // Remove possible iptables entries
+ containerIptablesClear("ipv4", fmt.Sprintf("%s", c.Name()), "nat")
+
// Check that we actually have devices to remove
if !shared.PathExists(c.DevicesPath()) {
return nil
diff --git a/lxd/networks_iptables.go b/lxd/iptables.go
similarity index 62%
rename from lxd/networks_iptables.go
rename to lxd/iptables.go
index 1c0c2bc88..313a48014 100644
--- a/lxd/networks_iptables.go
+++ b/lxd/iptables.go
@@ -8,7 +8,8 @@ import (
"github.com/lxc/lxd/shared"
)
-func networkIptablesPrepend(protocol string, netName string, table string,
chain string, rule ...string) error {
+func iptablesPrepend(protocol string, comment string, table string, chain
string,
+ rule ...string) error {
cmd := "iptables"
if protocol == "ipv6" {
cmd = "ip6tables"
@@ -28,7 +29,7 @@ func networkIptablesPrepend(protocol string, netName string,
table string, chain
// Check for an existing entry
args := append(baseArgs, []string{"-C", chain}...)
args = append(args, rule...)
- args = append(args, "-m", "comment", "--comment",
fmt.Sprintf("generated for LXD network %s", netName))
+ args = append(args, "-m", "comment", "--comment",
fmt.Sprintf("generated for %s", comment))
_, err = shared.RunCommand(cmd, args...)
if err == nil {
return nil
@@ -37,7 +38,7 @@ func networkIptablesPrepend(protocol string, netName string,
table string, chain
// Add the rule
args = append(baseArgs, []string{"-I", chain}...)
args = append(args, rule...)
- args = append(args, "-m", "comment", "--comment",
fmt.Sprintf("generated for LXD network %s", netName))
+ args = append(args, "-m", "comment", "--comment",
fmt.Sprintf("generated for %s", comment))
_, err = shared.TryRunCommand(cmd, args...)
if err != nil {
@@ -47,7 +48,7 @@ func networkIptablesPrepend(protocol string, netName string,
table string, chain
return nil
}
-func networkIptablesClear(protocol string, netName string, table string) error
{
+func iptablesClear(protocol string, comment string, table string) error {
// Detect kernels that lack IPv6 support
if !shared.PathExists("/proc/sys/net/ipv6") && protocol == "ipv6" {
return nil
@@ -73,11 +74,11 @@ func networkIptablesClear(protocol string, netName string,
table string) error {
args := append(baseArgs, "-S")
output, err := shared.TryRunCommand(cmd, args...)
if err != nil {
- return fmt.Errorf("Failed to list %s rules for %s (table %s)",
protocol, netName, table)
+ return fmt.Errorf("Failed to list %s rules for %s (table %s)",
protocol, comment, table)
}
for _, line := range strings.Split(output, "\n") {
- if !strings.Contains(line, fmt.Sprintf("generated for LXD
network %s", netName)) {
+ if !strings.Contains(line, fmt.Sprintf("generated for %s",
comment)) {
continue
}
@@ -94,3 +95,25 @@ func networkIptablesClear(protocol string, netName string,
table string) error {
return nil
}
+
+func networkIptablesPrepend(protocol string, comment string, table string,
chain string,
+ rule ...string) error {
+ return iptablesPrepend(protocol, fmt.Sprintf("LXD network %s", comment),
+ table, chain, rule...)
+}
+
+func networkIptablesClear(protocol string, comment string, table string) error
{
+ return iptablesClear(protocol, fmt.Sprintf("LXD network %s", comment),
+ table)
+}
+
+func containerIptablesPrepend(protocol string, comment string, table string,
+ chain string, rule ...string) error {
+ return iptablesPrepend(protocol, fmt.Sprintf("LXD container %s",
comment),
+ table, chain, rule...)
+}
+
+func containerIptablesClear(protocol string, comment string, table string)
error {
+ return iptablesClear(protocol, fmt.Sprintf("LXD container %s", comment),
+ table)
+}
From 4259015631623ca27fabc491f51f904d07002ac9 Mon Sep 17 00:00:00 2001
From: Thomas Hipp <thomas.h...@canonical.com>
Date: Wed, 11 Jul 2018 15:39:12 +0200
Subject: [PATCH 2/2] test: Add NAT tests
Signed-off-by: Thomas Hipp <thomas.h...@canonical.com>
---
test/suites/proxy.sh | 36 ++++++++++++++++++++++++++++++++++++
1 file changed, 36 insertions(+)
diff --git a/test/suites/proxy.sh b/test/suites/proxy.sh
index 9a75d9084..94ddf6ec5 100755
--- a/test/suites/proxy.sh
+++ b/test/suites/proxy.sh
@@ -92,6 +92,42 @@ test_proxy_device_tcp() {
# Cleanup
lxc delete -f proxyTester
+
+ # Try NAT
+ lxc init testimage nattest
+
+ lxc network create lxdt$$ dns.domain=test dns.mode=managed
+ lxc network attach lxdt$$ nattest eth0
+ v4_addr="$(lxc network get lxdt$$ ipv4.address | cut -d/ -f1)0"
+ lxc config device set nattest eth0 ipv4.address "${v4_addr}"
+
+ lxc start nattest
+ [ "$(iptables -t nat -S | grep -c "generated for LXD container nattest
(proxyDev)")" -eq 0 ]
+
+ lxc config device add nattest validNAT proxy listen="tcp:127.0.0.1:1234"
connect="tcp:${v4_addr}:1234"
+ [ "$(iptables -t nat -S | grep -c "generated for LXD container nattest
(validNAT)")" -eq 2 ]
+
+ lxc config device remove nattest validNAT
+ [ "$(iptables -t nat -S | grep -c "generated for LXD container nattest
(validNAT)")" -eq 0 ]
+
+ lxc config device add nattest validNAT proxy
listen="tcp:127.0.0.1:1234-1235" connect="tcp:${v4_addr}:1234"
+ [ "$(iptables -t nat -S | grep -c "generated for LXD container nattest
(validNAT)")" -eq 4 ]
+
+ lxc config device remove nattest validNAT
+ [ "$(iptables -t nat -S | grep -c "generated for LXD container nattest
(validNAT)")" -eq 0 ]
+
+ lxc config device add nattest validNAT proxy
listen="tcp:127.0.0.1:1234-1235" connect="tcp:${v4_addr}:1234-1235"
+ [ "$(iptables -t nat -S | grep -c "generated for LXD container nattest
(validNAT)")" -eq 4 ]
+
+ # This won't enable NAT
+ lxc config device add nattest invalidNAT proxy listen="tcp:127.0.0.1:1234"
connect="udp:${v4_addr}:1234"
+ [ "$(iptables -t nat -S | grep -c "generated for LXD container nattest
(invalidNAT)")" -eq 0 ]
+ [ "$(iptables -t nat -S | grep -c "generated for LXD container nattest
(validNAT)")" -eq 4 ]
+
+ lxc delete -f nattest
+ [ "$(iptables -t nat -S | grep -c "generated for LXD container nattest
(validNAT)")" -eq 0 ]
+
+ lxc network delete lxdt$$
}
test_proxy_device_unix() {
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