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Merge pull request #55 from eko/rework-network
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Rework network to allow IP generation range from 127.1.2.1 to 127.255.255.255
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@eko
eko authored Oct 30, 2020
2 parents dbc3a85 + 887bdeb commit deefeca
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Showing 3 changed files with 158 additions and 56 deletions.
81 changes: 46 additions & 35 deletions pkg/proxy/network.go
View file
Original file line number Diff line number Diff line change
Expand Up @@ -24,18 +24,17 @@ func init() {
func getNetworkInterface() (string, error) {
ifaces, err := net.Interfaces()
if err != nil {
fmt.Println("Cannot retrieve interfaces list: ", err)
return "", err
return "", fmt.Errorf("cannot retrieve interfaces list: %v", err)
}

for _, i := range ifaces {
ifaceFlags := i.Flags.String()
for _, iface := range ifaces {
ifaceFlags := iface.Flags.String()
if strings.Contains(ifaceFlags, "loopback") {
return i.Name, nil
return iface.Name, nil
}
}

return "", errors.New("Unable to find loopback network interface")
return "", errors.New("unable to find 'loopback' network interface")
}

// getAddIPCommandWithArgs returns the command (ifconfig, ip, ...) that will be used for the current OS
Expand Down Expand Up @@ -67,52 +66,64 @@ func getAddIPCommandWithArgs(ip string) (string, []string) {
return command, args
}

func generateIP(a byte, b byte, c byte, d int, port string) (net.IP, error) {
ip := net.IPv4(a, b, c, byte(d))

func assignIpToPort(a, b, c, d byte, port string) (byte, byte, byte, byte, error) {
// Retrieve network interface
iface, err := net.InterfaceByName(networkInterface)
if err != nil {
return net.IP{}, err
return a, b, c, d, err
}

command, args := getAddIPCommandWithArgs(ip.String())
for {
// Maximum IP bytes reached
if b == 255 && c == 255 && d == 255 {
break
}

for i := d; i < 255; i++ {
ip = net.IPv4(a, b, c, byte(i))
ip := net.IPv4(a, b, c, d)

addrs, err := iface.Addrs()
if err != nil {
return net.IP{}, err
return a, b, c, d, err
}

// Try to assign port to the IP addresses already assigned to the interface
for _, addr := range addrs {
if addr.String() == ip.String()+"/8" {
conn, err := net.Dial("tcp", fmt.Sprintf("%s:%s", ip.String(), port))
if err != nil {
return net.IPv4(a, b, c, byte(i)), nil
}
if conn != nil {
conn.Close()
}
// In case IP is already assigned to network interface, don't try to create it again
if !isAlreadyAssigned(ip, addrs) {
command, args := getAddIPCommandWithArgs(ip.String())

if err := exec.Command(command, args...).Run(); err != nil {
return a, b, c, d, fmt.Errorf("error while trying to run ifconfig/ip command to add new IP address (%s) on network interface '%s': %v", ip.String(), networkInterface, err)
}
}

// No already assigned IP/Port available, add IP address to the network interface
if err := exec.Command(command, args...).Run(); err != nil {
return net.IP{}, fmt.Errorf("Cannot run ifconfig command to add new IP address (%s) on network interface '%s': %v", ip.String(), networkInterface, err)
// Can't be contacted on ip/port? it means this couple is free to be used
if !canDial(ip.String(), port) {
return a, b, c, d, nil
}

// Try to assign port to the newly assigned IP
conn, err := net.Dial("tcp", fmt.Sprintf("%s:%s", ip.String(), port))
if err != nil {
return net.IPv4(a, b, c, byte(i)), nil
}
if conn != nil {
conn.Close()
a, b, c, d = getNextIPAddress(a, b, c, d)
}

return a, b, c, d, fmt.Errorf("unable to find an available IP/Port (ip: %d.%d.%d.%d:%s)", a, b, c, d, port)
}

func isAlreadyAssigned(ip net.IP, addrs []net.Addr) bool {
for _, addr := range addrs {
if addr.String() == ip.String()+"/8" {
return true
}
}

return net.IP{}, fmt.Errorf("Unable to find an available IP/Port (ip: %d.%d.%d.%d:%s)", a, b, c, d, port)
return false
}

func canDial(ip, port string) bool {
conn, err := net.Dial("tcp", fmt.Sprintf("%s:%s", ip, port))
if conn != nil {
conn.Close()
}
if err != nil {
return false
}

return true
}
56 changes: 38 additions & 18 deletions pkg/proxy/proxy.go
View file
Original file line number Diff line number Diff line change
Expand Up @@ -32,8 +32,10 @@ type proxy struct {
addProxyForwardMux sync.Mutex
listenerMux sync.Mutex
latestPort string
attributedIPs map[string]net.IP
ipLastByte int
lastIpByteA byte
lastIpByteB byte
lastIpByteC byte
lastIpByteD byte
view ui.View
}

Expand All @@ -45,8 +47,10 @@ func NewProxy(view ui.View, hostfile hostfile.Hostfile) *proxy {
listeners: make(map[string]net.Listener),
listening: true,
latestPort: ProxyPortStart,
attributedIPs: make(map[string]net.IP, 0),
ipLastByte: 1,
lastIpByteA: 127,
lastIpByteB: 0,
lastIpByteC: 1,
lastIpByteD: 0,
view: view,
}
}
Expand Down Expand Up @@ -160,27 +164,43 @@ func (p *proxy) AddProxyForward(name string, proxyForward *ProxyForward) {
}

func (p *proxy) generateIP(pf *ProxyForward) error {
// Create new listener on a dedicated IP address if the service
// does not already have an IP address attributed, elsewhere give the already
// attributed address
var localIP net.IP
var err error
if v, ok := p.attributedIPs[pf.Name]; ok {
localIP = v
} else {
localIP, err = generateIP(127, 1, 2, p.ipLastByte, pf.LocalPort)
p.ipLastByte = p.ipLastByte + 1
if err != nil {
return err
}

a, b, c, d := getNextIPAddress(p.lastIpByteA, p.lastIpByteB, p.lastIpByteC, p.lastIpByteD)

p.lastIpByteA = a
p.lastIpByteB = b
p.lastIpByteC = c
p.lastIpByteD = d

a, b, c, d, err = assignIpToPort(a, b, c, d, pf.LocalPort)
if err != nil {
return err
}

p.attributedIPs[pf.Name] = localIP
pf.SetLocalIP(localIP.String())
ip := net.IPv4(a, b, c, d)
pf.SetLocalIP(ip.String())

return nil
}

func getNextIPAddress(a, b, c, d byte) (byte, byte, byte, byte) {
if b == 255 && c == 255 && d == 255 {
return a, b, c, d
} else if c == 255 && d == 255 {
b++
c = 1
d = 1
} else if d == 255 {
c++
d = 1
} else {
d++
}

return a, b, c, d
}

func (p *proxy) generateProxyPort(proxyForward *ProxyForward) {
integerPort, _ := strconv.Atoi(p.latestPort)
p.latestPort = strconv.Itoa(integerPort + 1)
Expand Down
77 changes: 74 additions & 3 deletions pkg/proxy/proxy_test.go
View file
Original file line number Diff line number Diff line change
Expand Up @@ -3,6 +3,7 @@
package proxy

import (
"fmt"
"testing"

"github.com/eko/monday/pkg/hostfile"
Expand All @@ -29,7 +30,7 @@ func TestNewProxy(t *testing.T) {

assert.Len(t, p.ProxyForwards, 0)
assert.Equal(t, p.latestPort, "9400")
assert.Equal(t, p.ipLastByte, 1)
assert.Equal(t, p.ipLastByte, byte(1))
}

func TestAddProxyForward(t *testing.T) {
Expand All @@ -53,7 +54,7 @@ func TestAddProxyForward(t *testing.T) {
// Then
assert.Len(t, proxy.ProxyForwards, 1)
assert.Equal(t, proxy.latestPort, "9401")
assert.Equal(t, proxy.ipLastByte, 2)
assert.Equal(t, proxy.ipLastByte, byte(2))
}

func TestAddProxyForwardWhenMultiple(t *testing.T) {
Expand Down Expand Up @@ -120,5 +121,75 @@ func TestListen(t *testing.T) {

assert.Len(t, proxy.ProxyForwards, 1)
assert.Equal(t, proxy.latestPort, "9401")
assert.Equal(t, proxy.ipLastByte, 2)
assert.Equal(t, proxy.ipLastByte, byte(2))
}

func TestGetNextIPAddress(t *testing.T) {
testCases := []struct {
a byte
b byte
c byte
d byte

expectedA byte
expectedB byte
expectedC byte
expectedD byte
}{
{ // Case incrementing d
a: 127, b: 0, c: 0, d: 1,
expectedA: 127, expectedB: 0, expectedC: 0, expectedD: 2,
},
{ // Case incrementing d to last byte
a: 127, b: 0, c: 0, d: 254,
expectedA: 127, expectedB: 0, expectedC: 0, expectedD: 255,
},
{ // Case incrementing c and reset d to 1
a: 127, b: 0, c: 0, d: 255,
expectedA: 127, expectedB: 0, expectedC: 1, expectedD: 1,
},
{ // Case incrementing d to last byte
a: 127, b: 0, c: 1, d: 254,
expectedA: 127, expectedB: 0, expectedC: 1, expectedD: 255,
},
{ // Case incrementing c and reset d to 1
a: 127, b: 0, c: 1, d: 255,
expectedA: 127, expectedB: 0, expectedC: 2, expectedD: 1,
},
{ // Case incrementing d to last byte
a: 127, b: 0, c: 254, d: 254,
expectedA: 127, expectedB: 0, expectedC: 254, expectedD: 255,
},
{ // Case incrementing c and reset d to 1
a: 127, b: 0, c: 254, d: 255,
expectedA: 127, expectedB: 0, expectedC: 255, expectedD: 1,
},
{ // Case incrementing d to last byte when c is already on latest byte
a: 127, b: 0, c: 255, d: 254,
expectedA: 127, expectedB: 0, expectedC: 255, expectedD: 255,
},
{ // Case incrementing b and reset c and d to last byte
a: 127, b: 0, c: 255, d: 255,
expectedA: 127, expectedB: 1, expectedC: 1, expectedD: 1,
},
{ // Case incrementing d to last byte when b and c are already on latest byte
a: 127, b: 255, c: 255, d: 254,
expectedA: 127, expectedB: 255, expectedC: 255, expectedD: 255,
},
{ // Reached max level
a: 127, b: 255, c: 255, d: 255,
expectedA: 127, expectedB: 255, expectedC: 255, expectedD: 255,
},
}

for i, testCase := range testCases {
t.Run(fmt.Sprintf("Case %d", i), func(t *testing.T) {
a, b, c, d := getNextIPAddress(testCase.a, testCase.b, testCase.c, testCase.d)

assert.Equal(t, testCase.expectedA, a)
assert.Equal(t, testCase.expectedB, b)
assert.Equal(t, testCase.expectedC, c)
assert.Equal(t, testCase.expectedD, d)
})
}
}

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