fix(minecraft/client): strip FML data from address

Forge suffixes the server address with \x00FML3\x00. We remove that by
default in the parsed version of the handshake (the original is left
untouched) to make it easier to work with.

internal/minecraft/client.go

@@ -18,6 +18,7 @@ package minecraft
 import (
 	"encoding/json"
 	"fmt"
+	"strings"
 
 	mcnet "github.com/Tnze/go-mc/net"
 	pk "github.com/Tnze/go-mc/net/packet"
@@ -59,7 +60,10 @@ type Handshake struct {
 	ProtocolVersion int32
 
 	// ServerAddress is the address of the server the client is trying to
-	// connect to.
+	// connect to. If there are any NULL characters, they are
+	// automatically stripped as well as all content after them. This is
+	// to handle the case of Forge servers where the server address is
+	// suffixed with \0x00FML3\0x00.
 	ServerAddress string
 
 	// ServerPort is the port of the server the client is trying to
@@ -89,6 +93,13 @@ func (c *Client) Handshake() (*Handshake, error) {
 		return nil, fmt.Errorf("failed to scan packet: %w", err)
 	}
 
+	// if there's null characters in the server address, use the data
+	// before the first null character.
+	nullData := strings.Split(h.ServerAddress, "\x00")
+	if len(nullData) > 0 {
+		h.ServerAddress = nullData[0]
+	}
+
 	// set the protocol version on the client.
 	c.ProtocolVersion = h.ProtocolVersion