Make log messages more descriptive (#34)

ban.go

@@ -4,13 +4,13 @@ import (
 	"database/sql"
 	"encoding/binary"
 	"errors"
+	"fmt"
 	"net"
 
 	"github.com/anon55555/mt/rudp"
 	_ "github.com/mattn/go-sqlite3"
 )
 
-var ErrAlreadyBanned = errors.New("ip address is already banned")
 var ErrInvalidAddress = errors.New("invalid ip address format")
 
 // addBanItem inserts a ban DB entry
@@ -106,7 +106,7 @@ func (p *Peer) Ban() error {
 	}
 
 	if banned {
-		return ErrAlreadyBanned
+		return fmt.Errorf("ip address %s is already banned", p.Addr().String())
 	}
 
 	db, err := initAuthDB()

hand.go

@@ -1,13 +1,11 @@
 package main
 
 import (
-	"errors"
+	"fmt"
 
 	"github.com/anon55555/mt"
 )
 
-var ErrNoHandCaps = errors.New("hand tool capabilities missing")
-
 func (p *Peer) UpdateHandCapabs() error {
 	l := p.Inv().List("hand")
 	if l == nil {
@@ -27,7 +25,7 @@ func (p *Peer) UpdateHandCapabs() error {
 
 		caps := handcapabs[p.ServerName()]
 		if caps == nil {
-			return ErrNoHandCaps
+			return fmt.Errorf("hand tool capabilities of server %s missing", p.ServerName())
 		}
 
 		s, err := caps.SerializeJSON()

peer.go

@@ -1,7 +1,7 @@
 package main
 
 import (
-	"errors"
+	"fmt"
 	"net"
 	"sync"
 	"time"
@@ -10,8 +10,6 @@ import (
 	"github.com/anon55555/mt/rudp"
 )
 
-var ErrServerUnreachable = errors.New("server is unreachable")
-
 var connectedPeers int = 0
 var connectedPeersMu sync.RWMutex
 
@@ -136,7 +134,7 @@ func Connect(conn net.PacketConn, addr net.Addr) (*Peer, error) {
 		srv.SendDisco(0, true)
 		srv.Close()
 
-		return nil, ErrServerUnreachable
+		return nil, fmt.Errorf("server at %s is unreachable", addr.String())
 	case <-ack:
 	}