Fix missing from tag and branch creation

client.go

@@ -91,7 +91,10 @@ func clientRequestBuildReq(c *Client, req *sip.Request) error {
 	// A valid SIP request formulated by a UAC MUST, at a minimum, contain
 	// the following header fields: To, From, CSeq, Call-ID, Max-Forwards,
 	// and Via;
-	ClientRequestAddVia(c, req)
+	if _, exists := req.Via(); !exists {
+		// Multi VIA value must be manually added
+		ClientRequestAddVia(c, req)
+	}
 
 	if _, exists := req.From(); !exists {
 		from := sip.FromHeader{
@@ -103,7 +106,9 @@ func clientRequestBuildReq(c *Client, req *sip.Request) error {
 				UriParams: sip.NewParams(),
 				Headers:   sip.NewParams(),
 			},
+			Params: sip.NewParams(),
 		}
+		from.Params.Add("tag", sip.GenerateTagN(16))
 		req.AppendHeader(&from)
 	}
 
@@ -117,6 +122,7 @@ func clientRequestBuildReq(c *Client, req *sip.Request) error {
 				UriParams: req.Recipient.UriParams,
 				Headers:   req.Recipient.Headers,
 			},
+			Params: sip.NewParams(),
 		}
 		req.AppendHeader(&to)
 	}

client_test.go

@@ -26,7 +26,7 @@ func TestClientRequestBuild(t *testing.T) {
 
 	from, exists := req.From()
 	assert.True(t, exists)
-	assert.Equal(t, "\"sipgo\" <sip:[email protected]>", from.Value())
+	assert.Equal(t, "\"sipgo\" <sip:[email protected]>;tag="+from.Params["tag"], from.Value())
 
 	to, exists := req.To()
 	assert.True(t, exists)

sip/headers.go

@@ -977,7 +977,6 @@ func (h *RecordRouteHeader) cloneFirst() *RecordRouteHeader {
 // Copy all headers of one type from one message to another.
 // Appending to any headers that were already there.
 func CopyHeaders(name string, from, to Message) {
-	name = HeaderToLower(name)
 	for _, h := range from.GetHeaders(name) {
 		to.AppendHeader(h.headerClone())
 	}

sip/sip.go

@@ -39,10 +39,16 @@ func GenerateBranchN(n int) string {
 }
 
 func generateBranchStringWrite(sb *strings.Builder, n int) {
-	sb.Grow(len(RFC3261BranchMagicCookie) + 33)
+	sb.Grow(len(RFC3261BranchMagicCookie) + n + 1)
 	sb.WriteString(RFC3261BranchMagicCookie)
 	sb.WriteString(".")
-	RandStringBytesMask(sb, 32)
+	RandStringBytesMask(sb, n)
+}
+
+func GenerateTagN(n int) string {
+	sb := &strings.Builder{}
+	RandStringBytesMask(sb, n)
+	return sb.String()
 }
 
 // DefaultPort returns protocol default port by network.