From 8f91c777559748fa6e857d9fc1f4ae079a532813 Mon Sep 17 00:00:00 2001
From: Christopher Speller <crspeller@gmail.com>
Date: Mon, 3 Oct 2016 16:03:15 -0400
Subject: Adding ability to serve TLS directly from Mattermost server (#4119)

---
 vendor/github.com/miekg/dns/generate.go | 159 ++++++++++++++++++++++++++++++++
 1 file changed, 159 insertions(+)
 create mode 100644 vendor/github.com/miekg/dns/generate.go

(limited to 'vendor/github.com/miekg/dns/generate.go')

diff --git a/vendor/github.com/miekg/dns/generate.go b/vendor/github.com/miekg/dns/generate.go
new file mode 100644
index 000000000..e4481a4b0
--- /dev/null
+++ b/vendor/github.com/miekg/dns/generate.go
@@ -0,0 +1,159 @@
+package dns
+
+import (
+	"bytes"
+	"errors"
+	"fmt"
+	"strconv"
+	"strings"
+)
+
+// Parse the $GENERATE statement as used in BIND9 zones.
+// See http://www.zytrax.com/books/dns/ch8/generate.html for instance.
+// We are called after '$GENERATE '. After which we expect:
+// * the range (12-24/2)
+// * lhs (ownername)
+// * [[ttl][class]]
+// * type
+// * rhs (rdata)
+// But we are lazy here, only the range is parsed *all* occurrences
+// of $ after that are interpreted.
+// Any error are returned as a string value, the empty string signals
+// "no error".
+func generate(l lex, c chan lex, t chan *Token, o string) string {
+	step := 1
+	if i := strings.IndexAny(l.token, "/"); i != -1 {
+		if i+1 == len(l.token) {
+			return "bad step in $GENERATE range"
+		}
+		if s, err := strconv.Atoi(l.token[i+1:]); err == nil {
+			if s < 0 {
+				return "bad step in $GENERATE range"
+			}
+			step = s
+		} else {
+			return "bad step in $GENERATE range"
+		}
+		l.token = l.token[:i]
+	}
+	sx := strings.SplitN(l.token, "-", 2)
+	if len(sx) != 2 {
+		return "bad start-stop in $GENERATE range"
+	}
+	start, err := strconv.Atoi(sx[0])
+	if err != nil {
+		return "bad start in $GENERATE range"
+	}
+	end, err := strconv.Atoi(sx[1])
+	if err != nil {
+		return "bad stop in $GENERATE range"
+	}
+	if end < 0 || start < 0 || end < start {
+		return "bad range in $GENERATE range"
+	}
+
+	<-c // _BLANK
+	// Create a complete new string, which we then parse again.
+	s := ""
+BuildRR:
+	l = <-c
+	if l.value != zNewline && l.value != zEOF {
+		s += l.token
+		goto BuildRR
+	}
+	for i := start; i <= end; i += step {
+		var (
+			escape bool
+			dom    bytes.Buffer
+			mod    string
+			err    error
+			offset int
+		)
+
+		for j := 0; j < len(s); j++ { // No 'range' because we need to jump around
+			switch s[j] {
+			case '\\':
+				if escape {
+					dom.WriteByte('\\')
+					escape = false
+					continue
+				}
+				escape = true
+			case '$':
+				mod = "%d"
+				offset = 0
+				if escape {
+					dom.WriteByte('$')
+					escape = false
+					continue
+				}
+				escape = false
+				if j+1 >= len(s) { // End of the string
+					dom.WriteString(fmt.Sprintf(mod, i+offset))
+					continue
+				} else {
+					if s[j+1] == '$' {
+						dom.WriteByte('$')
+						j++
+						continue
+					}
+				}
+				// Search for { and }
+				if s[j+1] == '{' { // Modifier block
+					sep := strings.Index(s[j+2:], "}")
+					if sep == -1 {
+						return "bad modifier in $GENERATE"
+					}
+					mod, offset, err = modToPrintf(s[j+2 : j+2+sep])
+					if err != nil {
+						return err.Error()
+					}
+					j += 2 + sep // Jump to it
+				}
+				dom.WriteString(fmt.Sprintf(mod, i+offset))
+			default:
+				if escape { // Pretty useless here
+					escape = false
+					continue
+				}
+				dom.WriteByte(s[j])
+			}
+		}
+		// Re-parse the RR and send it on the current channel t
+		rx, err := NewRR("$ORIGIN " + o + "\n" + dom.String())
+		if err != nil {
+			return err.Error()
+		}
+		t <- &Token{RR: rx}
+		// Its more efficient to first built the rrlist and then parse it in
+		// one go! But is this a problem?
+	}
+	return ""
+}
+
+// Convert a $GENERATE modifier 0,0,d to something Printf can deal with.
+func modToPrintf(s string) (string, int, error) {
+	xs := strings.SplitN(s, ",", 3)
+	if len(xs) != 3 {
+		return "", 0, errors.New("bad modifier in $GENERATE")
+	}
+	// xs[0] is offset, xs[1] is width, xs[2] is base
+	if xs[2] != "o" && xs[2] != "d" && xs[2] != "x" && xs[2] != "X" {
+		return "", 0, errors.New("bad base in $GENERATE")
+	}
+	offset, err := strconv.Atoi(xs[0])
+	if err != nil || offset > 255 {
+		return "", 0, errors.New("bad offset in $GENERATE")
+	}
+	width, err := strconv.Atoi(xs[1])
+	if err != nil || width > 255 {
+		return "", offset, errors.New("bad width in $GENERATE")
+	}
+	switch {
+	case width < 0:
+		return "", offset, errors.New("bad width in $GENERATE")
+	case width == 0:
+		return "%" + xs[1] + xs[2], offset, nil
+	}
+	return "%0" + xs[1] + xs[2], offset, nil
+}
-- 
cgit v1.2.3-1-g7c22