options{,_test}: add Options.BootFileURL and tests

options.go

@@ -6,6 +6,7 @@ import (
 	"encoding/binary"
 	"errors"
 	"net"
+	"net/url"
 	"sort"
 	"time"
 )
@@ -467,6 +468,25 @@ func (o Options) IAPrefix() ([]*IAPrefix, bool, error) {
 	return iaprefix, true, nil
 }
 
+// BootFileURL returns the Boot File URL Option value, described in RFC 5970,
+// Section 3.1.
+//
+// The URL return value contains a URL which may be used by clients to obtain
+// a boot file for PXE.
+//
+// The boolean return value indicates if OptionBootFileURL was present in the
+// Options map.  The error return value indicates if a valid boot file URL
+// could not be parsed from the option.
+func (o Options) BootFileURL() (*url.URL, bool, error) {
+	v, ok := o.Get(OptionBootFileURL)
+	if !ok {
+		return nil, false, nil
+	}
+
+	u, err := url.Parse(string(v))
+	return u, true, err
+}
+
 // parseClasses parses multiple contiguous byte slices contained in
 // OptionUserClass or OptionVendorClass, of the form:
 //   - 2 bytes: length

options_test.go

@@ -3,7 +3,9 @@ package dhcp6
 import (
 	"bytes"
 	"encoding"
+	"errors"
 	"net"
+	"net/url"
 	"reflect"
 	"testing"
 	"time"
@@ -1476,6 +1478,69 @@ func TestOptionsIAPrefix(t *testing.T) {
 	}
 }
 
+// TestOptionsBootFileURL verifies that Options.BootFileURL properly parses
+// and returns a URL, if it is available with OptionBootFileURL.
+func TestOptionsBootFileURL(t *testing.T) {
+	var tests = []struct {
+		description string
+		options     Options
+		u           *url.URL
+		ok          bool
+		err         error
+	}{
+		{
+			description: "OptionBootFileURL not present in Options map",
+		},
+		{
+			description: "OptionBootFileURL present in Options map, but invalid URL",
+			options: Options{
+				OptionBootFileURL: [][]byte{[]byte("http://www.%a0.com/foo")},
+			},
+			err: &url.Error{
+				Op:  "parse",
+				URL: "http://www.%a0.com/foo",
+				Err: errors.New("hexadecimal escape in host"),
+			},
+		},
+		{
+			description: "OptionBootFileURL present in Options map",
+			options: Options{
+				OptionBootFileURL: [][]byte{[]byte("tftp://192.168.1.1:69")},
+			},
+			u: &url.URL{
+				Scheme: "tftp",
+				Host:   "192.168.1.1:69",
+			},
+			ok: true,
+		},
+	}
+
+	for i, tt := range tests {
+		u, ok, err := tt.options.BootFileURL()
+		if err != nil {
+			if want, got := tt.err.Error(), err.Error(); want != got {
+				t.Fatalf("[%02d] test %q, unexpected error for Options.BootFileURL(): %v != %v",
+					i, tt.description, want, got)
+			}
+
+			continue
+		}
+
+		if want, got := tt.ok, ok; want != got {
+			t.Fatalf("[%02d] test %q, unexpected ok for Options.BootFileURL(): %v != %v",
+				i, tt.description, want, got)
+		}
+		if !ok {
+			continue
+		}
+
+		if want, got := tt.u.String(), u.String(); want != got {
+			t.Fatalf("[%02d] test %q, unexpected value for Options.BootFileURL(): %v != %v",
+				i, tt.description, want, got)
+		}
+	}
+}
+
 // TestOptions_enumerate verifies that Options.enumerate correctly enumerates
 // and sorts an Options map into key/value option pairs.
 func TestOptions_enumerate(t *testing.T) {