Handshake a peer

1 files changed, 26 insertions, 0 deletions

diff --git a/src/peer_protocol.zig b/src/peer_protocol.zig
new file mode 100644
index 0000000..cd70ad2
--- /dev/null
+++ b/src/peer_protocol.zig
@@ -0,0 +1,26 @@
+const std = @import("std");
+
+pub const Handshake = struct {
+    info_hash: [20]u8,
+    peer_id: [20]u8,
+
+    pub fn read(reader: anytype) !Handshake {
+        var msg = [_]u8{0} ** 68;
+        try reader.readNoEof(&msg);
+        if (msg[0] != 19) return error.ProtocolError;
+        if (!std.mem.eql(u8, msg[1..20], "BitTorrent protocol")) return error.ProtocolError;
+        //if (!std.mem.allEqual(u8, msg[20..28], 0)) return error.ProtocolError;
+        var res: Handshake = undefined;
+        @memcpy(&res.info_hash, msg[28..48]);
+        @memcpy(&res.peer_id, msg[48..68]);
+        return res;
+    }
+
+    pub fn write(self: Handshake, writer: anytype) !void {
+        try writer.writeByte(19);
+        try writer.writeAll("BitTorrent protocol");
+        try writer.writeByteNTimes(0, 8);
+        try writer.writeAll(&self.info_hash);
+        try writer.writeAll(&self.peer_id);
+    }
+};