Adding the HostName field to the Conn struct (#18)

Changing the internal-only match interface to return any parsed
hostnames.

It can be useful for implementers of Target to be able to inspect
the already-parsed SNI header (in the case of TLS) or host header
(in the case of http) to know what host was asked for by the client
in order to make additional routing decisions.  This can be used
by transparent reverse proxies where the destination is not known
in advance.

1 files changed, 9 insertions, 8 deletions

diff --git a/sni.go b/sni.go
index 44f5796..53b53c2 100644
--- a/sni.go
+++ b/sni.go
@@ -73,11 +73,12 @@ type sniMatch struct {
 	target  Target
 }
 
-func (m sniMatch) match(br *bufio.Reader) Target {
-	if m.matcher(context.TODO(), clientHelloServerName(br)) {
-		return m.target
+func (m sniMatch) match(br *bufio.Reader) (Target, string) {
+	sni := clientHelloServerName(br)
+	if m.matcher(context.TODO(), sni) {
+		return m.target, sni
 	}
-	return nil
+	return nil, ""
 }
 
 // acmeMatch matches "*.acme.invalid" ACME tls-sni-01 challenges and
@@ -87,10 +88,10 @@ type acmeMatch struct {
 	cfg *config
 }
 
-func (m *acmeMatch) match(br *bufio.Reader) Target {
+func (m *acmeMatch) match(br *bufio.Reader) (Target, string) {
 	sni := clientHelloServerName(br)
 	if !strings.HasSuffix(sni, ".acme.invalid") {
-		return nil
+		return nil, ""
 	}
 
 	// TODO: cache. ACME issuers will hit multiple times in a short
@@ -107,12 +108,12 @@ func (m *acmeMatch) match(br *bufio.Reader) Target {
 	}
 	for range m.cfg.acmeTargets {
 		if target := <-ch; target != nil {
-			return target
+			return target, sni
 		}
 	}
 
 	// No target was happy with the provided challenge.
-	return nil
+	return nil, ""
 }
 
 func tryACME(ctx context.Context, ch chan<- Target, dest Target, sni string) {