sanity check

src/main/java/emu/grasscutter/server/packet/recv/HandlerSetPlayerBirthdayReq.java

@@ -11,23 +11,57 @@ import emu.grasscutter.server.packet.send.PacketSetPlayerBirthdayRsp;
 
 @Opcodes(PacketOpcodes.SetPlayerBirthdayReq)
 public class HandlerSetPlayerBirthdayReq extends PacketHandler {
-    @Override
-    public void handle(GameSession session, byte[] header, byte[] payload) throws Exception {
-        SetPlayerBirthdayReq req = SetPlayerBirthdayReq.parseFrom(payload);
+	@Override
+	public void handle(GameSession session, byte[] header, byte[] payload) throws Exception {
+		SetPlayerBirthdayReq req = SetPlayerBirthdayReq.parseFrom(payload);
 
-        if (req.getBirthday().getDay() > 0 && req.getBirthday().getMonth() > 0) {
-            int day = req.getBirthday().getDay();
-            int month = req.getBirthday().getMonth();
+		// RET_BIRTHDAY_CANNOT_BE_SET_TWICE = 7009
+		if (session.getPlayer().hasBirthday()) {
+			session.send(new PacketSetPlayerBirthdayRsp(7009));
+			return;
+		}
 
-            // Update birthday value
-            session.getPlayer().setBirthday(day, month);
+		int month = req.getBirthday().getMonth();
+		int day = req.getBirthday().getDay();
 
-            // Save birthday month and day
-            session.getPlayer().save();
-            SocialDetail.Builder detail = session.getPlayer().getSocialDetail();
+		// RET_BIRTHDAY_FORMAT_ERROR = 7022
+		if (!isValidBirthday(month, day)) {
+			session.send(new PacketSetPlayerBirthdayRsp(7022));
+			return;
+		}
+
+		// Update birthday value
+		session.getPlayer().setBirthday(day, month);
+
+		// Save birthday month and day
+		session.getPlayer().save();
+		SocialDetail.Builder detail = session.getPlayer().getSocialDetail();
+
+		session.send(new PacketSetPlayerBirthdayRsp(session.getPlayer()));
+		session.send(new PacketGetPlayerSocialDetailRsp(detail));
+	}
+
+	private boolean isValidBirthday(int month, int day) {
+
+		switch (month) {
+			case 1:
+			case 3:
+			case 5:
+			case 7:
+			case 8:
+			case 10:
+			case 12:
+				return day > 0 & day <= 31;
+			case 4:
+			case 6:
+			case 9:
+			case 11:
+				return day > 0 && day <= 30;
+			case 2:
+				return day > 0 & day <= 29;
+		}
+
+		return false;
+	}
 
-            session.send(new PacketSetPlayerBirthdayRsp(session.getPlayer()));
-            session.send(new PacketGetPlayerSocialDetailRsp(detail));
-        }
-    }
 }

src/main/java/emu/grasscutter/server/packet/send/PacketSetPlayerBirthdayRsp.java

@@ -6,13 +6,24 @@ import emu.grasscutter.net.packet.PacketOpcodes;
 import emu.grasscutter.net.proto.SetPlayerBirthdayRspOuterClass.SetPlayerBirthdayRsp;
 
 public class PacketSetPlayerBirthdayRsp extends GenshinPacket {
-    public PacketSetPlayerBirthdayRsp(GenshinPlayer player) {
-        super(PacketOpcodes.SetPlayerBirthdayRsp);
 
-        SetPlayerBirthdayRsp proto = SetPlayerBirthdayRsp.newBuilder()
-                .setBirthday(player.getBirthday().toProto())
-                .build();
+	public PacketSetPlayerBirthdayRsp(int retCode) {
+		super(PacketOpcodes.SetPlayerBirthdayRsp);
 
-        this.setData(proto);
-    }
+		SetPlayerBirthdayRsp proto = SetPlayerBirthdayRsp.newBuilder()
+				.setRetcode(retCode)
+				.build();
+
+		this.setData(proto);
+	}
+
+	public PacketSetPlayerBirthdayRsp(GenshinPlayer player) {
+		super(PacketOpcodes.SetPlayerBirthdayRsp);
+
+		SetPlayerBirthdayRsp proto = SetPlayerBirthdayRsp.newBuilder()
+				.setBirthday(player.getBirthday().toProto())
+				.build();
+
+		this.setData(proto);
+	}
 }