feat(p2p/messages): add sendheaders (#146)

src/network/protocol/messages/lib.zig

@@ -12,6 +12,7 @@ pub const SendCmpctMessage = @import("sendcmpct.zig").SendCmpctMessage;
 pub const FilterClearMessage = @import("filterclear.zig").FilterClearMessage;
 pub const FilterAddMessage = @import("filteradd.zig").FilterAddMessage;
 pub const NotFoundMessage = @import("notfound.zig").NotFoundMessage;
+pub const SendHeadersMessage = @import("sendheaders.zig").SendHeadersMessage;
 
 pub const InventoryVector = struct {
     type: u32,
@@ -57,6 +58,7 @@ pub const MessageTypes = enum {
     filterclear,
     filteradd,
     notfound,
+    sendheaders,
 };
 
 pub const Message = union(MessageTypes) {
@@ -73,6 +75,7 @@ pub const Message = union(MessageTypes) {
     filterclear: FilterClearMessage,
     filteradd: FilterAddMessage,
     notfound: NotFoundMessage,
+    sendheaders: SendHeadersMessage,
 
     pub fn name(self: Message) *const [12]u8 {
         return switch (self) {
@@ -89,6 +92,7 @@ pub const Message = union(MessageTypes) {
             .filterclear => |m| @TypeOf(m).name(),
             .filteradd => |m| @TypeOf(m).name(),
             .notfound => |m| @TypeOf(m).name(),
+            .sendheaders => |m| @TypeOf(m).name(),
         };
     }
 
@@ -107,6 +111,7 @@ pub const Message = union(MessageTypes) {
             .filterclear => {},
             .filteradd => |m| m.deinit(allocator),
             .notfound => {},
+            .sendheaders => {},
         }
     }
 
@@ -125,6 +130,7 @@ pub const Message = union(MessageTypes) {
             .filterclear => |m| m.checksum(),
             .filteradd => |m| m.checksum(),
             .notfound => |m| m.checksum(),
+            .sendheaders => |m| m.checksum(),
         };
     }
 
@@ -143,6 +149,7 @@ pub const Message = union(MessageTypes) {
             .filterclear => |m| m.hintSerializedLen(),
             .filteradd => |m| m.hintSerializedLen(),
             .notfound => |m| m.hintSerializedLen(),
+            .sendheaders => |m| m.hintSerializedLen(),
         };
     }
 };

src/network/protocol/messages/sendheaders.zig

@@ -0,0 +1,59 @@
+const std = @import("std");
+const protocol = @import("../lib.zig");
+
+/// SendHeaders represents the "getaddr" message
+///
+/// https://developer.bitcoin.org/reference/p2p_networking.html#sendheaders
+pub const SendHeadersMessage = struct {
+    // sendheaders message do not contain any payload, thus there is no field
+    const Self = @This();
+
+    pub fn new() Self {
+        return .{};
+    }
+
+    pub fn name() *const [12]u8 {
+        return protocol.CommandNames.SENDHEADERS;
+    }
+
+    pub fn checksum(self: Self) [4]u8 {
+        _ = self;
+        // If payload is empty, the checksum is always 0x5df6e0e2 (SHA256(SHA256("")))
+        return [4]u8{ 0x5d, 0xf6, 0xe0, 0xe2 };
+    }
+
+    /// Serialize a message as bytes and return them.
+    pub fn serialize(self: *const Self, allocator: std.mem.Allocator) ![]u8 {
+        _ = self;
+        _ = allocator;
+        return &.{};
+    }
+
+    pub fn deserializeReader(allocator: std.mem.Allocator, r: anytype) !Self {
+        _ = allocator;
+        _ = r;
+        return SendHeadersMessage{};
+    }
+
+    pub fn hintSerializedLen(self: Self) usize {
+        _ = self;
+        return 0;
+    }
+};
+
+// TESTS
+
+test "ok_full_flow_SendHeaders" {
+    const allocator = std.testing.allocator;
+
+    {
+        const msg = SendHeadersMessage{};
+
+        const payload = try msg.serialize(allocator);
+        defer allocator.free(payload);
+        const deserialized_msg = try SendHeadersMessage.deserializeReader(allocator, payload);
+        _ = deserialized_msg;
+
+        try std.testing.expect(payload.len == 0);
+    }
+}

src/network/wire/lib.zig

@@ -135,6 +135,8 @@ pub fn receiveMessage(
         protocol.messages.Message{ .notfound = try protocol.messages.NotFoundMessage.deserializeReader(allocator, r) }
     else if (std.mem.eql(u8, &command, protocol.messages.FeeFilterMessage.name()))
         protocol.messages.Message{ .feefilter = try protocol.messages.FeeFilterMessage.deserializeReader(allocator, r) }
+    else if (std.mem.eql(u8, &command, protocol.messages.SendHeadersMessage.name()))
+        protocol.messages.Message{ .sendheaders = try protocol.messages.SendHeadersMessage.deserializeReader(allocator, r) }
     else {
         try r.skipBytes(payload_len, .{}); // Purge the wire
         return error.UnknownMessage;
@@ -399,6 +401,32 @@ test "ok_send_pong_message" {
     }
 }
 
+test "ok_send_sendheaders_message" {
+    const Config = @import("../../config/config.zig").Config;
+    const ArrayList = std.ArrayList;
+    const test_allocator = std.testing.allocator;
+    const SendHeadersMessage = protocol.messages.SendHeadersMessage;
+
+    var list: std.ArrayListAligned(u8, null) = ArrayList(u8).init(test_allocator);
+    defer list.deinit();
+
+    const message = SendHeadersMessage.new();
+
+    const received_message = try write_and_read_message(
+        test_allocator,
+        &list,
+        Config.BitcoinNetworkId.MAINNET,
+        Config.PROTOCOL_VERSION,
+        message,
+    ) orelse unreachable;
+    defer received_message.deinit(test_allocator);
+
+    switch (received_message) {
+        .sendheaders => {},
+        else => unreachable,
+    }
+}
+
 test "ko_receive_invalid_payload_length" {
     const Config = @import("../../config/config.zig").Config;
     const ArrayList = std.ArrayList;