support encrypted streams with SRTP and MIKEY (#520) (#809)

pkg/headers/rtp_info.go

@@ -0,0 +1,101 @@
+package headers
+
+import (
+	"fmt"
+	"strconv"
+	"strings"
+
+	"github.com/bluenviron/gortsplib/v4/pkg/base"
+)
+
+// RTPInfoEntry is an entry of a RTP-Info header.
+type RTPInfoEntry struct {
+	URL            string
+	SequenceNumber *uint16
+	Timestamp      *uint32
+}
+
+// RTPInfo is a RTP-Info header.
+type RTPInfo []*RTPInfoEntry
+
+// Unmarshal decodes a RTP-Info header.
+func (h *RTPInfo) Unmarshal(v base.HeaderValue) error {
+	if len(v) == 0 {
+		return fmt.Errorf("value not provided")
+	}
+
+	if len(v) > 1 {
+		return fmt.Errorf("value provided multiple times (%v)", v)
+	}
+
+	for _, part := range strings.Split(v[0], ",") {
+		e := &RTPInfoEntry{}
+
+		// remove leading spaces
+		part = strings.TrimLeft(part, " ")
+
+		kvs, err := keyValParse(part, ';')
+		if err != nil {
+			return err
+		}
+
+		urlReceived := false
+
+		for k, v := range kvs {
+			switch k {
+			case "url":
+				e.URL = v
+				urlReceived = true
+
+			case "seq":
+				vi, err := strconv.ParseUint(v, 10, 16)
+				if err != nil {
+					return err
+				}
+				vi2 := uint16(vi)
+				e.SequenceNumber = &vi2
+
+			case "rtptime":
+				vi, err := strconv.ParseUint(v, 10, 32)
+				if err != nil {
+					return err
+				}
+				vi2 := uint32(vi)
+				e.Timestamp = &vi2
+
+			default:
+				// ignore non-standard keys
+			}
+		}
+
+		if !urlReceived {
+			return fmt.Errorf("URL is missing")
+		}
+
+		*h = append(*h, e)
+	}
+
+	return nil
+}
+
+// Marshal encodes a RTP-Info header.
+func (h RTPInfo) Marshal() base.HeaderValue {
+	rets := make([]string, len(h))
+
+	for i, e := range h {
+		var tmp []string
+		tmp = append(tmp, "url="+e.URL)
+
+		if e.SequenceNumber != nil {
+			tmp = append(tmp, "seq="+strconv.FormatUint(uint64(*e.SequenceNumber), 10))
+		}
+
+		if e.Timestamp != nil {
+			tmp = append(tmp, "rtptime="+strconv.FormatUint(uint64(*e.Timestamp), 10))
+		}
+
+		rets[i] = strings.Join(tmp, ";")
+	}
+
+	return base.HeaderValue{strings.Join(rets, ",")}
+}