feat: add support for ipv4 peers (#121)

src/network/message/utils.zig

@@ -0,0 +1,18 @@
+const std = @import("std");
+
+pub fn convertIPv4ToIPv6(address: std.net.Address) std.net.Address {
+ // Convert IPv4 to IPv6-mapped IPv4 address
+ const ipv4_address = address.in;
+
+ var ipv6_mapped: [16]u8 = [_]u8{0} ** 16;
+
+ // Set bytes 10 and 11 to 0xff
+ ipv6_mapped[10] = 0xff;
+ ipv6_mapped[11] = 0xff;
+
+ // Copy the IPv4 address into the last 4 bytes of the IPv6-mapped address
+ const ipv4_bytes = std.mem.asBytes(&ipv4_address.sa.addr);
+ @memcpy(ipv6_mapped[12..16], ipv4_bytes[0..4]);
+
+ return std.net.Address.initIp6(ipv6_mapped, ipv4_address.getPort(), 0, 0);
+}

src/network/peer.zig

@@ -3,6 +3,7 @@ const net = std.net;
 const protocol = @import("./protocol/lib.zig");
 const wire = @import("./wire/lib.zig");
 const Config = @import("../config/config.zig").Config;
+const MessageUtils = @import("./message/utils.zig");
 
 pub const Boundness = enum {
  inbound,
@@ -89,11 +90,13 @@ pub const Peer = struct {
  }
 
  /// Send version message to peer
- fn sendVersionMessage(self: *Peer) !void {
+ fn sendVersionMessage(self: *const Peer) !void {
+ const address = if (self.address.any.family == std.posix.AF.INET) MessageUtils.convertIPv4ToIPv6(self.address) else self.address;
+
  const message = protocol.messages.VersionMessage.new(
  self.config.protocol_version,
  .{ .ip = std.mem.zeroes([16]u8), .port = 0, .services = self.config.services },
- .{ .ip = self.address.in6.sa.addr, .port = self.address.in6.getPort(), .services = 0 },
+ .{ .ip = address.in6.sa.addr, .port = address.in6.getPort(), .services = 0 },
  std.crypto.random.int(u64),
  self.config.bestBlock(),
  );