commit f4a836e2d2cedcd9ad44eca8f4dba7d180ef19ef
parent cc6fb3938d82d3ea7ce8abe0dfe9029385983b00
Author: mdnrz <mehdeenoroozi@gmail.com>
Date: Tue, 8 Apr 2025 15:46:05 +0330
add message rate limit
Diffstat:
| M | gotel.go | | | 56 | ++++++++++++++++++++++++++++++++++++++++++++++++++++---- |
1 file changed, 52 insertions(+), 4 deletions(-)
diff --git a/gotel.go b/gotel.go
@@ -5,6 +5,7 @@ import (
"net"
"time"
"strings"
+ "fmt"
)
type msgType int
@@ -18,15 +19,21 @@ const (
type Client struct {
UserName string
+ LastMsgTime time.Time
Request msgType
- Strike int
+ Strike int
Banned bool
- BannedAt time.Time
+ BanEnd time.Time
Conn net.Conn
Text string
}
-const Port = "6969"
+const (
+ msgCoolDownTimeSec = 1
+ banLimit = 5
+ banTimeoutSec = 180
+ Port = "6969"
+)
func addClient(conn net.Conn, Client_q chan Client) {
loginPrompt := "Who are you?\n> "
@@ -51,6 +58,30 @@ func addClient(conn net.Conn, Client_q chan Client) {
}
}
+func canMessage(client *Client) bool {
+ if !client.Banned {
+ diff := time.Now().Sub(client.LastMsgTime).Seconds();
+ if diff <= msgCoolDownTimeSec {
+ client.Strike += 1;
+ if client.Strike >= banLimit {
+ client.Banned = true;
+ client.BanEnd = time.Now().Add(banTimeoutSec * time.Second)
+ }
+ return false;
+ }
+ return true
+ }
+ banTimeRemaining := client.BanEnd.Sub(time.Now()).Seconds();
+ if banTimeRemaining >= 0.0 {
+ banTimeRemainingStr := fmt.Sprintf("You're banned. Try again in %.0f seconds.\n", banTimeRemaining)
+ client.Conn.Write([]byte(banTimeRemainingStr));
+ return false;
+ }
+ client.Strike = 0;
+ client.Banned = false;
+ return true;
+}
+
func checkForDuplicateUN(needle string, heystack map[string]Client) bool {
for _, client := range heystack {
if client.UserName == needle { return true }
@@ -66,12 +97,19 @@ func server(Client_q chan Client) {
keyString := client.Conn.RemoteAddr().String();
switch client.Request {
case msgConnect:
+ // TODO: implement rate limit for connection requests
log.Printf("Got login request from %s\n", keyString);
clientsOffline[keyString] = client;
case msgText:
clientOffline, ok := clientsOffline[keyString];
if ok {
+ if !canMessage(&clientOffline) {
+ clientsOffline[keyString] = clientOffline
+ break;
+ }
clientOffline.UserName = strings.TrimRight(client.Text, "\r\n");
+ clientOffline.LastMsgTime = time.Now();
+ clientsOffline[keyString] = clientOffline
if checkForDuplicateUN(clientOffline.UserName, clientsOnline) {
_, err := clientsOffline[keyString].Conn.Write([]byte("UserName already exists; Try something else\n> "));
if err != nil {
@@ -88,8 +126,18 @@ func server(Client_q chan Client) {
}
break;
}
- author, _ := clientsOnline[keyString];
+
+ author, ok := clientsOnline[keyString];
+ if !ok {
+ log.Fatal("cannot find client\n");
+ }
+ if !canMessage(&author) {
+ clientsOnline[keyString] = author
+ break;
+ }
+ author.LastMsgTime = time.Now()
author.Text = client.Text;
+ clientsOnline[keyString] = author
for _, value := range clientsOnline {
if value.Conn == author.Conn {
continue
