From ccfd2ac36f61e306698e25e1252a5836980e85f8 Mon Sep 17 00:00:00 2001
From: wish <wish@sek.ai>
Date: Sun, 12 Mar 2023 23:29:50 +1100
Subject: [PATCH] create RNG in token module

---
 common/token/token.go                        | 13 +++++++++++--
 server/channelserver/handlers_cast_binary.go |  5 ++---
 server/channelserver/handlers_event.go       |  6 +++---
 server/channelserver/handlers_festa.go       |  5 ++---
 server/signserver/dsgn_resp.go               |  5 +----
 5 files changed, 19 insertions(+), 15 deletions(-)

diff --git a/common/token/token.go b/common/token/token.go
index 73568bcbc..c474fdaf5 100644
--- a/common/token/token.go
+++ b/common/token/token.go
@@ -1,13 +1,22 @@
 package token
 
-import "math/rand"
+import (
+	"math/rand"
+	"time"
+)
 
 // Generate returns an alphanumeric token of specified length
 func Generate(length int) string {
+	rng := RNG()
 	var chars = []rune("abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789")
 	b := make([]rune, length)
 	for i := range b {
-		b[i] = chars[rand.Intn(len(chars))]
+		b[i] = chars[rng.Intn(len(chars))]
 	}
 	return string(b)
 }
+
+// RNG returns a new RNG generator
+func RNG() *rand.Rand {
+	return rand.New(rand.NewSource(time.Now().UnixNano()))
+}
diff --git a/server/channelserver/handlers_cast_binary.go b/server/channelserver/handlers_cast_binary.go
index 10d15938a..1b6b9a6ba 100644
--- a/server/channelserver/handlers_cast_binary.go
+++ b/server/channelserver/handlers_cast_binary.go
@@ -4,13 +4,13 @@ import (
 	"encoding/hex"
 	"erupe-ce/common/byteframe"
 	"erupe-ce/common/mhfcourse"
+	"erupe-ce/common/token"
 	"erupe-ce/config"
 	"erupe-ce/network/binpacket"
 	"erupe-ce/network/mhfpacket"
 	"fmt"
 	"golang.org/x/exp/slices"
 	"math"
-	"math/rand"
 	"strings"
 	"time"
 
@@ -370,8 +370,7 @@ func handleMsgSysCastBinary(s *Session, p mhfpacket.MHFPacket) {
 			roll.SetLE()
 			roll.WriteUint16(4) // Unk
 			roll.WriteUint16(authorLen)
-			rand.Seed(time.Now().UnixNano())
-			dice := fmt.Sprintf("%d", rand.Intn(100)+1)
+			dice := fmt.Sprintf("%d", token.RNG().Intn(100)+1)
 			roll.WriteUint16(uint16(len(dice) + 1))
 			roll.WriteNullTerminatedBytes([]byte(dice))
 			roll.WriteNullTerminatedBytes(tmp.ReadNullTerminatedBytes())
diff --git a/server/channelserver/handlers_event.go b/server/channelserver/handlers_event.go
index 1c8d3f319..bd44e8a10 100644
--- a/server/channelserver/handlers_event.go
+++ b/server/channelserver/handlers_event.go
@@ -1,8 +1,8 @@
 package channelserver
 
 import (
+	"erupe-ce/common/token"
 	"math"
-	"math/rand"
 	"time"
 
 	"erupe-ce/common/byteframe"
@@ -95,9 +95,9 @@ func generateFeatureWeapons(count int) activeFeature {
 	}
 	nums := make([]int, 0)
 	var result int
-	r := rand.New(rand.NewSource(time.Now().UnixNano()))
+	rng := token.RNG()
 	for len(nums) < count {
-		num := r.Intn(14)
+		num := rng.Intn(14)
 		exist := false
 		for _, v := range nums {
 			if v == num {
diff --git a/server/channelserver/handlers_festa.go b/server/channelserver/handlers_festa.go
index 2659aae1d..155cee3d8 100644
--- a/server/channelserver/handlers_festa.go
+++ b/server/channelserver/handlers_festa.go
@@ -4,8 +4,8 @@ import (
 	"encoding/hex"
 	"erupe-ce/common/byteframe"
 	ps "erupe-ce/common/pascalstring"
+	"erupe-ce/common/token"
 	"erupe-ce/network/mhfpacket"
-	"math/rand"
 	"sort"
 	"time"
 )
@@ -336,8 +336,7 @@ func handleMsgMhfEntryFesta(s *Session, p mhfpacket.MHFPacket) {
 		doAckSimpleFail(s, pkt.AckHandle, make([]byte, 4))
 		return
 	}
-	rand.Seed(time.Now().UnixNano())
-	team := uint32(rand.Intn(2))
+	team := uint32(token.RNG().Intn(2))
 	switch team {
 	case 0:
 		s.server.db.Exec("INSERT INTO festa_registrations VALUES ($1, 'blue')", guild.ID)
diff --git a/server/signserver/dsgn_resp.go b/server/signserver/dsgn_resp.go
index 1fc78f3d9..3df3bdf71 100644
--- a/server/signserver/dsgn_resp.go
+++ b/server/signserver/dsgn_resp.go
@@ -7,11 +7,9 @@ import (
 	"erupe-ce/common/token"
 	"erupe-ce/server/channelserver"
 	"fmt"
-	"math/rand"
+	"go.uber.org/zap"
 	"strings"
 	"time"
-
-	"go.uber.org/zap"
 )
 
 func makeSignInFailureResp(respID RespID) []byte {
@@ -29,7 +27,6 @@ func (s *Session) makeSignInResp(uid int) []byte {
 		s.logger.Warn("Error getting characters from DB", zap.Error(err))
 	}
 
-	rand.Seed(time.Now().UnixNano())
 	sessToken := token.Generate(16)
 	s.server.registerToken(uid, sessToken)