Added ability to limit the number of concurrent client connections per ip

1 files changed, 76 insertions, 0 deletions

diff --git a/peripconn.go b/peripconn.go
new file mode 100644
index 0000000..2568477
--- /dev/null
+++ b/peripconn.go
@@ -0,0 +1,76 @@
+package fasthttp
+
+import (
+	"fmt"
+	"net"
+	"sync"
+)
+
+type perIPConnCounter struct {
+	lock sync.Mutex
+	m    map[uint32]int
+}
+
+func (cc *perIPConnCounter) Register(ip uint32) int {
+	cc.lock.Lock()
+	if cc.m == nil {
+		cc.m = make(map[uint32]int)
+	}
+	n := cc.m[ip] + 1
+	cc.m[ip] = n
+	cc.lock.Unlock()
+	return n
+}
+
+func (cc *perIPConnCounter) Unregister(ip uint32) {
+	cc.lock.Lock()
+	if cc.m == nil {
+		cc.lock.Unlock()
+		panic("BUG: perIPConnCounter.Register() wasn't called")
+	}
+	n := cc.m[ip] - 1
+	if n < 0 {
+		cc.lock.Unlock()
+		panic(fmt.Sprintf("BUG: negative per-ip counter=%d for ip=%d", n, ip))
+	}
+	cc.m[ip] = n
+	cc.lock.Unlock()
+}
+
+type perIPConn struct {
+	net.Conn
+
+	ip               uint32
+	perIPConnCounter *perIPConnCounter
+}
+
+func (c *perIPConn) Close() error {
+	err := c.Conn.Close()
+	c.perIPConnCounter.Unregister(c.ip)
+	return err
+}
+
+func getUint32IP(c net.Conn) uint32 {
+	addr := c.RemoteAddr()
+	ipAddr, ok := addr.(*net.TCPAddr)
+	if !ok {
+		return 0
+	}
+	return ip2uint32(ipAddr.IP.To4())
+}
+
+func ip2uint32(ip net.IP) uint32 {
+	if len(ip) != 4 {
+		return 0
+	}
+	return uint32(ip[0])<<24 | uint32(ip[1])<<16 | uint32(ip[2])<<8 | uint32(ip[3])
+}
+
+func uint322ip(ip uint32) net.IP {
+	b := make([]byte, 4)
+	b[0] = byte(ip >> 24)
+	b[1] = byte(ip >> 16)
+	b[2] = byte(ip >> 8)
+	b[3] = byte(ip)
+	return b
+}