Handshake a peer

2 files changed, 54 insertions, 3 deletions

diff --git a/src/main.zig b/src/main.zig
index 9966a55..d50cc90 100644
--- a/src/main.zig
+++ b/src/main.zig
@@ -1,8 +1,15 @@
 const std = @import("std");
 const MetaInfo = @import("metainfo.zig");
 const bencode = @import("bencode.zig");
+const AnyWriter = @import("anywriter.zig");
+const peerproto = @import("peer_protocol.zig");
+
+const prr = "00112233445566778899";
 
 pub fn main() !void {
+    var peer_id: [20]u8 = undefined;
+    @memcpy(&peer_id, prr);
+
     var gpa = std.heap.GeneralPurposeAllocator(.{}){};
     defer _ = gpa.deinit();
     const a = gpa.allocator();
@@ -27,7 +34,7 @@ pub fn main() !void {
     var info_hash = try mi.info.hash(a);
     var buf_left = [_]u8{0} ** 1024;
     try q.put("info_hash", &info_hash);
-    try q.put("peer_id", "00112233445566778899");
+    try q.put("peer_id", &peer_id);
     try q.put("port", "6881");
     try q.put("uploaded", "0");
     try q.put("downloaded", "0");
@@ -44,10 +51,27 @@ pub fn main() !void {
         defer trb.deinit(a);
         var tr = try TrackerResp.parse(a, trb);
         defer tr.deinit(a);
-        var w = std.io.getStdOut().writer();
+
         for (tr.peers) |peer| {
-            try std.fmt.format(w, "peer: {}\n", .{peer});
+            std.log.info("peer: {}", .{peer});
         }
+
+        // Handle peers... 
+
+
+        const p = tr.peers[0];
+        var ps = try std.net.tcpConnectToAddress(p);
+        defer ps.close();
+        var pw = ps.writer();
+        var pr = ps.reader();
+        var hs: peerproto.Handshake = .{
+            .info_hash = info_hash,
+            .peer_id = peer_id,
+        };
+
+        try hs.write(pw);
+        var phs = try peerproto.Handshake.read(pr);
+        std.log.info("peer at {} peer_id {s}", .{ p, std.fmt.fmtSliceHexLower(&phs.peer_id) });
     }
 }
 
@@ -95,6 +119,7 @@ const TrackerResp = struct {
     }
 };
 
+
 test {
     _ = bencode;
     _ = MetaInfo;
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);
+    }
+};