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Merged
gBillal merged 2 commits into from
May 18, 2026
Merged

feat(rtsp): parse client_port and server_port of transport header #14

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d9b6f9a
feat(rtsp): parse client_port and server_port of transport header
gBillal May 18, 2026
178716d
write mode and add tests
gBillal May 18, 2026
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176 changes: 122 additions & 54 deletions src/rtsp/rtsp.zig
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Original file line number Diff line number Diff line change
Expand Up @@ -86,6 +86,86 @@ pub const Header = struct {
name: []const u8,
value: []const u8,

pub const Transport = struct {
proto: enum { tcp, udp } = .udp,
/// False means multicast
unicast: bool = true,
interleaved: ?struct { u8, u8 } = null,
client_port: ?struct { u16, u16 } = null,
server_port: ?struct { u16, u16 } = null,
mode: Method = .PLAY,

pub const Error = error{InvalidTransportHeader};

pub fn parse(header_value: []const u8) Transport.Error!Transport {
var it = std.mem.splitScalar(u8, header_value, ';');
var transport: Transport = .{};

const protocol = it.next().?;
if (std.mem.eql(u8, protocol, "RTP/AVP")) {
transport.proto = .udp;
} else if (std.mem.eql(u8, protocol, "RTP/AVP/UDP")) {
transport.proto = .udp;
} else if (std.mem.eql(u8, protocol, "RTP/AVP/TCP")) {
transport.proto = .tcp;
} else {
return error.InvalidTransportHeader;
}

while (it.next()) |parameter| {
if (std.mem.eql(u8, parameter, "unicast")) {
transport.unicast = true;
} else if (std.mem.eql(u8, parameter, "multicast")) {
transport.unicast = false;
} else if (std.mem.startsWith(u8, parameter, "interleaved=")) {
transport.interleaved = parseRange(u8, parameter[12..]) catch return error.InvalidTransportHeader;
} else if (std.mem.startsWith(u8, parameter, "client_port=")) {
transport.client_port = parseRange(u16, parameter[12..]) catch return error.InvalidTransportHeader;
} else if (std.mem.startsWith(u8, parameter, "server_port=")) {
transport.server_port = parseRange(u16, parameter[12..]) catch return error.InvalidTransportHeader;
} else if (std.mem.startsWith(u8, parameter, "mode=")) {
const method = std.mem.trim(u8, parameter[5..], "\"");
if (std.ascii.eqlIgnoreCase(method, "play"))
transport.mode = .PLAY
else if (std.ascii.eqlIgnoreCase(method, "record"))
transport.mode = .RECORD
else
return error.InvalidTransportHeader;
}
}

return transport;
}

pub fn write(self: *const Transport, writer: *std.Io.Writer) std.Io.Writer.Error!void {
try writer.writeAll(if (self.proto == .tcp) "RTP/AVP/TCP" else "RTP/AVP");
if (self.unicast) try writer.writeAll(";unicast") else try writer.writeAll(";multicast");

if (self.interleaved) |interleaved|
try writer.print(";interleaved={}-{}", .{ interleaved.@"0", interleaved.@"1" });

if (self.client_port) |client_port|
try writer.print(";client_port={}-{}", .{ client_port.@"0", client_port.@"1" });

if (self.server_port) |server_port|
try writer.print(";server_port={}-{}", .{ server_port.@"0", server_port.@"1" });

switch (self.mode) {
.RECORD => try writer.writeAll(";mode=record"),
else => {},
}
}

fn parseRange(T: type, value: []const u8) !struct { T, T } {
if (std.mem.cutScalar(u8, value, '-')) |range| {
const left, const right = range;
return .{ try std.fmt.parseInt(T, left, 10), try std.fmt.parseInt(T, right, 10) };
}

return error.ParseError;
}
};

pub fn parse(line: []const u8) Error!Header {
const colon_index = std.mem.indexOfScalar(u8, line, ':') orelse return error.ParseError;

Expand Down Expand Up @@ -125,67 +205,55 @@ pub const Header = struct {
try header.write(&writer);
try std.testing.expectEqualStrings("CSeq: 2\r\n", writer.buffer[0..writer.end]);
}
};

pub const TransportHeader = struct {
proto: enum { tcp, udp } = .udp,
/// False means multicast
unicast: bool = true,
interleaved: ?struct { u8, u8 } = null,

pub const TransportError = error{InvalidTransportHeader};

pub fn parse(header_value: []const u8) TransportError!TransportHeader {
var it = std.mem.splitScalar(u8, header_value, ';');
var transport: TransportHeader = .{};

const protocol = it.next().?;
if (std.mem.eql(u8, protocol, "RTP/AVP")) {
transport.proto = .udp;
} else if (std.mem.eql(u8, protocol, "RTP/AVP/UDP")) {
transport.proto = .udp;
} else if (std.mem.eql(u8, protocol, "RTP/AVP/TCP")) {
transport.proto = .tcp;
} else {
return error.InvalidTransportHeader;
test "Transport: parse" {
{
const transport = try Transport.parse("RTP/AVP/TCP;unicast;interleaved=0-1");
try std.testing.expect(transport.unicast);
try std.testing.expectEqual(.tcp, transport.proto);
try std.testing.expectEqual(.{ 0, 1 }, transport.interleaved);
}

while (it.next()) |parameter| {
if (std.mem.eql(u8, parameter, "unicast")) {
transport.unicast = true;
} else if (std.mem.eql(u8, parameter, "multicast")) {
transport.unicast = false;
} else if (std.mem.startsWith(u8, parameter, "interleaved=")) {
var interleaved_it = std.mem.splitScalar(u8, parameter[12..], '-');
transport.interleaved = .{
std.fmt.parseInt(u8, interleaved_it.next().?, 10) catch return error.InvalidTransportHeader,
std.fmt.parseInt(u8, interleaved_it.rest(), 10) catch return error.InvalidTransportHeader,
};
}
{
const transport = try Transport.parse("RTP/AVP/UDP;client_port=15000-15001;mode=\"recOrd\"");
try std.testing.expect(transport.unicast);
try std.testing.expectEqual(.udp, transport.proto);
try std.testing.expectEqual(null, transport.interleaved);
try std.testing.expectEqual(.{ 15000, 15001 }, transport.client_port);
try std.testing.expectEqual(.RECORD, transport.mode);
}

if (transport.proto == .tcp and transport.interleaved == null) return error.InvalidTransportHeader;

return transport;
}

pub fn write(self: *const TransportHeader, writer: *std.Io.Writer) std.Io.Writer.Error!void {
try writer.writeAll(if (self.proto == .tcp) "RTP/AVP/TCP" else "RTP/AVP");
if (self.unicast) {
try writer.writeAll(";unicast");
} else {
try writer.writeAll(";multicast");
}
if (self.interleaved) |interleaved| {
try writer.print(";interleaved={}-{}", .{ interleaved.@"0", interleaved.@"1" });
{
const transport = try Transport.parse("RTP/AVP;unicast;server_port=35000-35001");
try std.testing.expect(transport.unicast);
try std.testing.expectEqual(.udp, transport.proto);
try std.testing.expectEqual(null, transport.interleaved);
try std.testing.expectEqual(null, transport.client_port);
try std.testing.expectEqual(.{ 35000, 35001 }, transport.server_port);
try std.testing.expectEqual(.PLAY, transport.mode);
}
}

test "parse transport header" {
const transport = try parse("RTP/AVP/TCP;unicast;interleaved=0-1");
try std.testing.expect(transport.unicast);
try std.testing.expectEqual(.tcp, transport.proto);
try std.testing.expectEqual(.{ 0, 1 }, transport.interleaved);
test "Transport: write" {
var buffer: [1024]u8 = undefined;
var w = std.Io.Writer.fixed(&buffer);

var t = Header.Transport{
.proto = .udp,
.client_port = .{ 23900, 23901 },
};
try t.write(&w);
try std.testing.expectEqualStrings("RTP/AVP;unicast;client_port=23900-23901", w.buffered());

_ = w.consumeAll();
t = .{ .proto = .tcp, .interleaved = .{ 0, 1 }, .mode = .RECORD };
try t.write(&w);
try std.testing.expectEqualStrings("RTP/AVP/TCP;unicast;interleaved=0-1;mode=record", w.buffered());

_ = w.consumeAll();
t = .{ .proto = .udp, .server_port = .{ 10000, 10001 } };
try t.write(&w);
try std.testing.expectEqualStrings("RTP/AVP;unicast;server_port=10000-10001", w.buffered());
}
};

Expand Down Expand Up @@ -320,7 +388,7 @@ pub const Writer = struct {
try self.writer.print("{}\r\n", .{size});
}

pub fn writeTransportHeader(self: *Writer, header: TransportHeader) std.Io.Writer.Error!void {
pub fn writeTransportHeader(self: *Writer, header: Header.Transport) std.Io.Writer.Error!void {
try self.writer.writeAll("Transport: ");
try header.write(self.writer);
try self.writeLineFeed();
Expand Down
4 changes: 2 additions & 2 deletions src/rtsp/server.zig
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Original file line number Diff line number Diff line change
Expand Up @@ -21,7 +21,7 @@ pub const Request = struct {
cseq: u32,
session: ?[]const u8,
authenticate: ?[]const u8,
transport: ?rtsp.TransportHeader,
transport: ?rtsp.Header.Transport,
content_length: u32,

pub const Error = error{
Expand All @@ -31,7 +31,7 @@ pub const Request = struct {
MissingSequenceHeader,
/// A request body is not expected for this METHOD.
BodyUnexpected,
} || rtsp.TransportHeader.TransportError;
} || rtsp.Header.Transport.Error;

pub fn parse(buffer: []const u8) !Head {
var it = std.mem.splitSequence(u8, buffer, "\r\n");
Expand Down
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