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core: moved interface utilities to dedicated package
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@ppacher
ppacher committed Jan 23, 2020
1 parent a33f88d commit a0e7566
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Showing 3 changed files with 89 additions and 38 deletions.
24 changes: 21 additions & 3 deletions core/dhcpserver/register.go
View file
Original file line number Diff line number Diff line change
Expand Up @@ -7,6 7,7 @@ import (
"github.com/apex/log"
"github.com/caddyserver/caddy"
"github.com/caddyserver/caddy/caddyfile"
"github.com/nextdhcp/nextdhcp/core/utils/iface"
)

const serverType = "dhcpv4"
Expand Down Expand Up @@ -49,9 50,12 @@ func (c *dhcpContext) InspectServerBlocks(sourceFile string, serverBlocks []cadd
logger: log.Log,
}

if err := tryInterfaceNameOrIP(k, cfg); err != nil {
return nil, fmt.Errorf("failed to get subnet configuration for server block %s (index = %d)", k, si)
ip, inet, err := iface.ByNameOrCIDR(k)
if err != nil {
return nil, fmt.Errorf("failed to get subnet configuration for server block %s (index = %d): %s", k, si, err.Error())
}
cfg.IP = ip
cfg.Network = *inet

configKey := keyForConfig(si)
c.addConfig(configKey, cfg)
Expand All @@ -64,7 68,7 @@ func (c *dhcpContext) InspectServerBlocks(sourceFile string, serverBlocks []cadd
startIP := net.ParseIP(s.Keys[0])
endIP := net.ParseIP(s.Keys[2])

iface, ipNet, err := findInterfaceContainingIP(startIP)
iface, ipNet, err := iface.Contains(startIP)
if err != nil {
return nil, err
}
Expand Down Expand Up @@ -131,3 135,17 @@ func (c *dhcpContext) MakeServers() ([]caddy.Server, error) {

return servers, nil
}

func findInterface(cfg *Config) bool {
if cfg.Interface.Name != "" && len(cfg.Interface.HardwareAddr) > 0 {
return true
}

iface, err := iface.ByIP(cfg.IP)
if err != nil {
return false
}

cfg.Interface = *iface
return true
}
50 changes: 15 additions & 35 deletions core/dhcpserver/interface.go → core/utils/iface/iface.go
View file
Original file line number Diff line number Diff line change
@@ -1,29 1,16 @@
package dhcpserver
// Package iface contains utility methods for interacting with
// network interface
package iface

import (
"fmt"
"net"
)

func findInterface(cfg *Config) bool {
if cfg.Interface.Name != "" && len(cfg.Interface.HardwareAddr) > 0 {
return true
}

iface, err := findInterfaceByIP(cfg.IP)
if err != nil {
//log.Println(err.Error())
return false
}

cfg.Interface = *iface
return true
}

// findInterfaceByIP searches for the network interface that has
// ByIP searches for the network interface that has
// ip assigned to it. The IP address must be the same, IPs in
// the same subnet do not count as a match
func findInterfaceByIP(ip net.IP) (*net.Interface, error) {
func ByIP(ip net.IP) (*net.Interface, error) {
ifaces, err := net.Interfaces()
if err != nil {
return nil, err
Expand All @@ -41,8 28,6 @@ func findInterfaceByIP(ip net.IP) (*net.Interface, error) {
continue
}

//log.Println(iface.Name, a)

if ipNet.IP.Equal(ip) {
return &iface, nil
}
Expand All @@ -52,9 37,9 @@ func findInterfaceByIP(ip net.IP) (*net.Interface, error) {
return nil, fmt.Errorf("failed to find interface for %s", ip.String())
}

// findInterfaceContainingIPs searches for the network interface that
// Contains searches for the network interface that
// contains the given IP address in one of it's attached local networks
func findInterfaceContainingIP(ip net.IP) (*net.Interface, *net.IPNet, error) {
func Contains(ip net.IP) (*net.Interface, *net.IPNet, error) {
ifaces, err := net.Interfaces()
if err != nil {
return nil, nil, err
Expand Down Expand Up @@ -82,28 67,26 @@ func findInterfaceContainingIP(ip net.IP) (*net.Interface, *net.IPNet, error) {
return nil, nil, fmt.Errorf("failed to find interface with %s", ip.String())
}

// tryInterfaceNameOrIP first tries to parse a CIDR IP subnet
// ByNameOrCIDR first tries to parse a CIDR IP subnet
// notation in value and will fill the IP and IPNet values of
// cfg accordingly. If value is not a valid CIDR notation
// it will assume value is the name of the interface and will
// lookup the IP configuration there. If that fails too, an
// error is returned
func tryInterfaceNameOrIP(value string, cfg *Config) error {
func ByNameOrCIDR(value string) (net.IP, *net.IPNet, error) {
ip, ipNet, err := net.ParseCIDR(value)
if err == nil {
cfg.IP = ip
cfg.Network = *ipNet
return nil
return ip, ipNet, nil
}

iface, err := net.InterfaceByName(value)
if err != nil {
return err
return nil, nil, err
}

addr, err := iface.Addrs()
if err != nil {
return err
return nil, nil, err
}

foundIPv4 := false
Expand All @@ -121,7 104,7 @@ func tryInterfaceNameOrIP(value string, cfg *Config) error {
}

if foundIPv4 {
return fmt.Errorf("interface names can only be used with one subnet assigned")
return nil, nil, fmt.Errorf("interface names can only be used with one subnet assigned")
}

foundIPv4 = true
Expand All @@ -131,11 114,8 @@ func tryInterfaceNameOrIP(value string, cfg *Config) error {
}

if !foundIPv4 {
return fmt.Errorf("no usable subnet found")
return nil, nil, fmt.Errorf("no usable subnet found")
}

cfg.IP = ip
cfg.Network = *ipNet

return nil
return ip, ipNet, nil
}
53 changes: 53 additions & 0 deletions core/utils/iface/iface_test.go
View file
Original file line number Diff line number Diff line change
@@ -0,0 1,53 @@
package iface

import (
"net"
"testing"

"github.com/stretchr/testify/assert"
"github.com/stretchr/testify/require"
)

func TestByIP(t *testing.T) {
iface, err := ByIP(net.IP{127, 0, 0, 1})
assert.NoError(t, err)
assert.Equal(t, "lo", iface.Name)

iface, err = ByIP(net.IP{127, 0, 1, 1})
assert.Error(t, err)
assert.Nil(t, iface)
}

func TestContains(t *testing.T) {
iface, inet, err := Contains(net.IP{127, 0, 0, 1})
assert.NoError(t, err)
assert.Equal(t, "lo", iface.Name)
assert.NotNil(t, inet)
assert.Equal(t, "127.0.0.1/8", inet.String())

iface, inet, err = Contains(net.IP{127, 0, 1, 1})
assert.NoError(t, err)
assert.Equal(t, "lo", iface.Name)
assert.NotNil(t, inet)
assert.Equal(t, "127.0.0.1/8", inet.String())

iface, inet, err = Contains(net.IP{1, 2, 3, 4})
assert.Error(t, err)
assert.Nil(t, iface)
assert.Nil(t, inet)
}

func TestByNameOrCIDR(t *testing.T) {
ip, inet, err := ByNameOrCIDR("lo")
require.NoError(t, err)
assert.Equal(t, "127.0.0.1", ip.String())
assert.Equal(t, "127.0.0.1/8", inet.String())

ip, inet, err = ByNameOrCIDR("127.0.0.1/8")
require.NoError(t, err)
assert.Equal(t, "127.0.0.1", ip.String())
assert.Equal(t, "127.0.0.0/8", inet.String())

ip, inet, err = ByNameOrCIDR("notAnIpOrInterface")
require.Error(t, err)
}

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