.drone.yml

@@ -2,7 +2,7 @@ kind: pipeline
 type: docker
 name: default
 steps:
-  - name: test
+  - name: Test
     image: golang
     commands:
       - go test ./...

cli.go

@@ -6,13 +6,13 @@ import (
 	"math/rand"
 	"runtime"
 	"strings"
-	"unsafe"
 
+	"git.froth.zone/sam/awl/conf"
 	"git.froth.zone/sam/awl/util"
+
 	"github.com/miekg/dns"
 	"github.com/urfave/cli/v2"
 	"golang.org/x/net/idna"
-	"golang.org/x/sys/windows"
 )
 
 // Do all the magic CLI crap
@@ -113,7 +113,7 @@ func prepareCLI() *cli.App {
 			},
 			&cli.BoolFlag{
 				Name:  "tc",
-				Usage: "set tc (TrunCated) flag (default: not set)",
+				Usage: "set TC (TrunCated) flag (default: not set)",
 			},
 			&cli.BoolFlag{
 				Name:  "z",
@@ -184,77 +184,13 @@ func parseArgs(args []string) (util.Answers, error) {
 		}
 	}
 	if resp.Answers.Server == "" {
-		var resolv *dns.ClientConfig
-		if runtime.GOOS == "windows" {
-			resolv, err = WindowsDnsClientConfig()
-		} else {
-			resolv, err = dns.ClientConfigFromFile("/etc/resolv.conf")
-		}
-		if err != nil { // Query Google by default, needed for Windows since the DNS library doesn't support Windows
-			// TODO: Actually find where windows stuffs its dns resolvers
+		resolv, err := conf.GetDNSConfig()
+		if err != nil { // Query Google by default
 			resp.Answers.Server = "8.8.4.4"
 		} else {
-			resp.Answers.Server = resolv.Servers[rand.Intn(len(resolv.Servers)-1)]
+			resp.Answers.Server = resolv.Servers[rand.Intn(len(resolv.Servers))]
 		}
 	}
 
 	return util.Answers{Server: resp.Answers.Server, Request: resp.Answers.Request, Name: resp.Answers.Name}, nil
 }
-
-/*
-"Stolen" from
-https://gist.github.com/moloch--/9fb1c8497b09b45c840fe93dd23b1e98
-*/
-
-// WindowsDnsClientConfig - returns all DNS server addresses using windows fuckery.
-func WindowsDnsClientConfig() (*dns.ClientConfig, error) {
-	l := uint32(20000)
-	b := make([]byte, l)
-
-	// Windows is an utter fucking trash fire of an operating system.
-	if err := windows.GetAdaptersAddresses(windows.AF_UNSPEC, windows.GAA_FLAG_INCLUDE_PREFIX, 0, (*windows.IpAdapterAddresses)(unsafe.Pointer(&b[0])), &l); err != nil {
-		return nil, err
-	}
-	var addresses []*windows.IpAdapterAddresses
-	for addr := (*windows.IpAdapterAddresses)(unsafe.Pointer(&b[0])); addr != nil; addr = addr.Next {
-		addresses = append(addresses, addr)
-	}
-
-	resolvers := map[string]bool{}
-	for _, addr := range addresses {
-		for next := addr.FirstUnicastAddress; next != nil; next = next.Next {
-			if addr.OperStatus != windows.IfOperStatusUp {
-				continue
-			}
-			if next.Address.IP() != nil {
-				for dnsServer := addr.FirstDnsServerAddress; dnsServer != nil; dnsServer = dnsServer.Next {
-					ip := dnsServer.Address.IP()
-					if ip.IsMulticast() || ip.IsLinkLocalMulticast() || ip.IsLinkLocalUnicast() || ip.IsUnspecified() {
-						continue
-					}
-					if ip.To16() != nil && strings.HasPrefix(ip.To16().String(), "fec0:") {
-						continue
-					}
-					resolvers[ip.String()] = true
-				}
-				break
-			}
-		}
-	}
-
-	// Take unique values only
-	servers := []string{}
-	for server := range resolvers {
-		servers = append(servers, server)
-	}
-
-	// TODO: Make configurable, based on defaults in https://github.com/miekg/dns/blob/master/clientconfig.go
-	return &dns.ClientConfig{
-		Servers:  servers,
-		Search:   []string{},
-		Port:     "53",
-		Ndots:    1,
-		Timeout:  5,
-		Attempts: 1,
-	}, nil
-}

conf/docs.go

@@ -0,0 +1,6 @@
+/*
+Helper functions for getting local nameservers
+
+Currently supported: Unix, Windows, Plan 9 (tested on 9front)
+*/
+package conf

conf/notwin.go

@@ -0,0 +1,52 @@
+// SPDX-License-Identifier: BSD-3-Clause
+//go:build !windows
+// +build !windows
+
+package conf
+
+import (
+	"os"
+	"runtime"
+	"strings"
+
+	"github.com/miekg/dns"
+)
+
+// Get the DNS configuration, either from /etc/resolv.conf or somewhere else
+func GetDNSConfig() (*dns.ClientConfig, error) {
+	if runtime.GOOS == "plan9" {
+		dat, err := os.ReadFile("/net/ndb")
+		if err != nil {
+			return nil, err
+		}
+		return getPlan9Config(string(dat))
+	} else {
+		return dns.ClientConfigFromFile("/etc/resolv.conf")
+	}
+}
+
+// Plan 9 stores its network data in /net/ndb, which seems to be formatted a specific way
+func getPlan9Config(str string) (*dns.ClientConfig, error) {
+	str = strings.ReplaceAll(str, "\n", "")
+	spl := strings.FieldsFunc(str, split)
+	servers := []string{}
+	for _, option := range spl {
+		if strings.HasPrefix(option, "dns=") {
+			servers = append(servers, strings.TrimPrefix(option, "dns="))
+		}
+	}
+
+	// TODO: read more about how customizable Plan 9 is
+	return &dns.ClientConfig{
+		Servers:  servers,
+		Search:   []string{},
+		Port:     "53",
+		Ndots:    1,
+		Timeout:  5,
+		Attempts: 1,
+	}, nil
+}
+
+func split(r rune) bool {
+	return r == ' ' || r == '\t'
+}

conf/notwin_test.go

@@ -0,0 +1,18 @@
+// SPDX-License-Identifier: BSD-3-Clause
+package conf
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestGetPlan9Config(t *testing.T) {
+	ndb := `ip=192.168.122.45 ipmask=255.255.255.0 ipgw=192.168.122.1
+	sys=chog9
+	dns=192.168.122.1`
+
+	act, err := getPlan9Config(ndb)
+	assert.Nil(t, err)
+	assert.Equal(t, act.Servers[0], "192.168.122.1")
+}

conf/win.go

@@ -0,0 +1,70 @@
+// SPDX-License-Identifier: BSD-3-Clause
+//go:build windows
+
+package conf
+
+import (
+	"strings"
+	"unsafe"
+
+	"github.com/miekg/dns"
+	"golang.org/x/sys/windows"
+)
+
+/*
+"Stolen" from
+https://gist.github.com/moloch--/9fb1c8497b09b45c840fe93dd23b1e98
+*/
+
+// WindowsDnsClientConfig - returns all DNS server addresses using windows fuckery.
+func GetDNSConfig() (*dns.ClientConfig, error) {
+	l := uint32(20000)
+	b := make([]byte, l)
+
+	// Windows is an utter fucking trash fire of an operating system.
+	if err := windows.GetAdaptersAddresses(windows.AF_UNSPEC, windows.GAA_FLAG_INCLUDE_PREFIX, 0, (*windows.IpAdapterAddresses)(unsafe.Pointer(&b[0])), &l); err != nil {
+		return nil, err
+	}
+	var addresses []*windows.IpAdapterAddresses
+	for addr := (*windows.IpAdapterAddresses)(unsafe.Pointer(&b[0])); addr != nil; addr = addr.Next {
+		addresses = append(addresses, addr)
+	}
+
+	resolvers := map[string]bool{}
+	for _, addr := range addresses {
+		for next := addr.FirstUnicastAddress; next != nil; next = next.Next {
+			if addr.OperStatus != windows.IfOperStatusUp {
+				continue
+			}
+			if next.Address.IP() != nil {
+				for dnsServer := addr.FirstDnsServerAddress; dnsServer != nil; dnsServer = dnsServer.Next {
+					ip := dnsServer.Address.IP()
+					if ip.IsMulticast() || ip.IsLinkLocalMulticast() || ip.IsLinkLocalUnicast() || ip.IsUnspecified() {
+						continue
+					}
+					if ip.To16() != nil && strings.HasPrefix(ip.To16().String(), "fec0:") {
+						continue
+					}
+					resolvers[ip.String()] = true
+				}
+				break
+			}
+		}
+	}
+
+	// Take unique values only
+	servers := []string{}
+	for server := range resolvers {
+		servers = append(servers, server)
+	}
+
+	// TODO: Make configurable, based on defaults in https://github.com/miekg/dns/blob/master/clientconfig.go
+	return &dns.ClientConfig{
+		Servers:  servers,
+		Search:   []string{},
+		Port:     "53",
+		Ndots:    1,
+		Timeout:  5,
+		Attempts: 1,
+	}, nil
+}