From d95111c5bde8360347e26a9d286bca588fb800ba Mon Sep 17 00:00:00 2001 From: dushixiang <798148596@qq.com> Date: Thu, 29 Oct 2020 11:28:17 +0800 Subject: [PATCH] Initial commit --- LICENSE | 339 ++++++++++++++++++++++++++++++++++++++++++++++++++++++ README.MD | 47 ++++++++ go.mod | 5 + go.sum | 16 +++ main.go | 242 ++++++++++++++++++++++++++++++++++++++ 5 files changed, 649 insertions(+) create mode 100644 LICENSE create mode 100644 README.MD create mode 100644 go.mod create mode 100644 go.sum create mode 100644 main.go diff --git a/LICENSE b/LICENSE new file mode 100644 index 0000000..d159169 --- /dev/null +++ b/LICENSE @@ -0,0 +1,339 @@ + GNU GENERAL PUBLIC LICENSE + Version 2, June 1991 + + Copyright (C) 1989, 1991 Free Software Foundation, Inc., + 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA + Everyone is permitted to copy and distribute verbatim copies + of this license document, but changing it is not allowed. + + Preamble + + The licenses for most software are designed to take away your +freedom to share and change it. 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See the + GNU General Public License for more details. + + You should have received a copy of the GNU General Public License along + with this program; if not, write to the Free Software Foundation, Inc., + 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA. + +Also add information on how to contact you by electronic and paper mail. + +If the program is interactive, make it output a short notice like this +when it starts in an interactive mode: + + Gnomovision version 69, Copyright (C) year name of author + Gnomovision comes with ABSOLUTELY NO WARRANTY; for details type `show w'. + This is free software, and you are welcome to redistribute it + under certain conditions; type `show c' for details. + +The hypothetical commands `show w' and `show c' should show the appropriate +parts of the General Public License. Of course, the commands you use may +be called something other than `show w' and `show c'; they could even be +mouse-clicks or menu items--whatever suits your program. + +You should also get your employer (if you work as a programmer) or your +school, if any, to sign a "copyright disclaimer" for the program, if +necessary. Here is a sample; alter the names: + + Yoyodyne, Inc., hereby disclaims all copyright interest in the program + `Gnomovision' (which makes passes at compilers) written by James Hacker. + + , 1 April 1989 + Ty Coon, President of Vice + +This General Public License does not permit incorporating your program into +proprietary programs. If your program is a subroutine library, you may +consider it more useful to permit linking proprietary applications with the +library. If this is what you want to do, use the GNU Lesser General +Public License instead of this License. diff --git a/README.MD b/README.MD new file mode 100644 index 0000000..338827a --- /dev/null +++ b/README.MD @@ -0,0 +1,47 @@ +## tcpwall +当我们想要阻止某些TCP连接的建立，在Linux平台上有一个很好的解决方案**iptables**，但是对那些已经建立的tcp连接，iptables就不能做到随心所欲的阻断了。 + +我在互联网上检索的时候发现了**tcpkill**这个工具，tcpkill是一个网络分析工具集**dsniff**中的一个小工具。在Linux上可以直接通过dsniff包安装，使用方式也非常简单。 + +通过测试我发现tcpkill在执行命令之后并不会立刻阻断tcp连接，而是等待有数据传输时，才会阻断，因此在执行完命令之后程序并不会主动退出，而是需要通过***Ctrl+C***来退出，这对于某些想要通过程序来调用的脚本小子（例如我）来说简直是个灾难。 + +## 如何阻断一个已经建立的tcp连接？ +阻断一个已经建立的tcp连接通常有这几种方案： +1. 服务端主动断开 +2. 客户端主动断开 +3. 拔掉网线（时间要超过tcp超时时间） +4. 伪造RST数据包发送给服务端和客户端让它们主动断开（tcpkill就是这么做的） + +前三种局限性太大，只能用第4种了。 + +## 如何实现伪造RST数据报文包？ + +[GoPacket](https://github.com/google/gopacket) 是go基于**libpcap**构建的一个库，可以通过旁路的方式接收一份数据包的拷贝。因此我们可以很方便捕获到正在通信的tcp数据报文。通过数据报文，我们可以获取到通信双方的MAC地址，IP和端口号，以及ACK号等，这些都是伪造数据包必不可少的。 + +在学习了**tcpkill**的源码之后，我使用go开发了一个增强版的**tcpwall**，**tcpwall**不仅可以实现和**tcpkill**同样的基于ip或端口监听到指定数据报文之后伪造RST数据报文来阻断tcp连接，也可以通过源ip源端口，目的ip目的端口来主动发送SYN数据报文包来诱导那些没有数据的tcp连接发送ACK数据报文包以获取源MAC、目的MAC和ACK号，并且可以通过指定参数让程序等待一段时间后主动退出。 + +## 如何使用 + +阻断指定IP和端口的TCP连接（不关心是源或者目的） +``` +tcpwall -i {interface} -host {host} -port {port} +``` + +阻断指定源IP和源端口的TCP连接 +``` +tcpwall -i {interface} -shost {src_host} -sport {src_port} +``` + +阻断指定目的IP和目的端口的TCP连接 +``` +tcpwall -i {interface} -dhost {dst_host} -dport {dst_port} +``` + +阻断指定源IP、源端口、目的IP、目的端口的TCP连接（会主动向双方发送SYN数据报文包） +``` +tcpwall -i {interface} -shost {src_host} -sport {src_port} -dhost {dst_host} -dport {dst_port} +``` + +## 其他 + + - -timeout 时间（秒）指定等待多久之后退出程序 \ No newline at end of file diff --git a/go.mod b/go.mod new file mode 100644 index 0000000..2de2407 --- /dev/null +++ b/go.mod @@ -0,0 +1,5 @@ +module tcpwall + +go 1.13 + +require github.com/google/gopacket v1.1.19 diff --git a/go.sum b/go.sum new file mode 100644 index 0000000..a915606 --- /dev/null +++ b/go.sum @@ -0,0 +1,16 @@ +github.com/google/gopacket v1.1.19 h1:ves8RnFZPGiFnTS0uPQStjwru6uO6h+nlr9j6fL7kF8= +github.com/google/gopacket v1.1.19/go.mod h1:iJ8V8n6KS+z2U1A8pUwu8bW5SyEMkXJB8Yo/Vo+TKTo= +golang.org/x/crypto v0.0.0-20190308221718-c2843e01d9a2/go.mod h1:djNgcEr1/C05ACkg1iLfiJU5Ep61QUkGW8qpdssI0+w= +golang.org/x/crypto v0.0.0-20191011191535-87dc89f01550/go.mod h1:yigFU9vqHzYiE8UmvKecakEJjdnWj3jj499lnFckfCI= +golang.org/x/lint v0.0.0-20200302205851-738671d3881b/go.mod h1:3xt1FjdF8hUf6vQPIChWIBhFzV8gjjsPE/fR3IyQdNY= +golang.org/x/mod v0.1.1-0.20191105210325-c90efee705ee/go.mod h1:QqPTAvyqsEbceGzBzNggFXnrqF1CaUcvgkdR5Ot7KZg= +golang.org/x/net v0.0.0-20190404232315-eb5bcb51f2a3/go.mod h1:t9HGtf8HONx5eT2rtn7q6eTqICYqUVnKs3thJo3Qplg= +golang.org/x/net v0.0.0-20190620200207-3b0461eec859 h1:R/3boaszxrf1GEUWTVDzSKVwLmSJpwZ1yqXm8j0v2QI= +golang.org/x/net v0.0.0-20190620200207-3b0461eec859/go.mod h1:z5CRVTTTmAJ677TzLLGU+0bjPO0LkuOLi4/5GtJWs/s= +golang.org/x/sync v0.0.0-20190423024810-112230192c58/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM= +golang.org/x/sys v0.0.0-20190215142949-d0b11bdaac8a/go.mod h1:STP8DvDyc/dI5b8T5hshtkjS+E42TnysNCUPdjciGhY= +golang.org/x/sys v0.0.0-20190412213103-97732733099d h1:+R4KGOnez64A81RvjARKc4UT5/tI9ujCIVX+P5KiHuI= +golang.org/x/sys v0.0.0-20190412213103-97732733099d/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs= +golang.org/x/text v0.3.0/go.mod h1:NqM8EUOU14njkJ3fqMW+pc6Ldnwhi/IjpwHt7yyuwOQ= +golang.org/x/tools v0.0.0-20200130002326-2f3ba24bd6e7/go.mod h1:TB2adYChydJhpapKDTa4BR/hXlZSLoq2Wpct/0txZ28= +golang.org/x/xerrors v0.0.0-20191011141410-1b5146add898/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0= diff --git a/main.go b/main.go new file mode 100644 index 0000000..9aad793 --- /dev/null +++ b/main.go @@ -0,0 +1,242 @@ +package main + +import ( + "flag" + "fmt" + "github.com/google/gopacket" + "github.com/google/gopacket/layers" + "github.com/google/gopacket/pcap" + "log" + "net" + "strconv" + "strings" + "time" +) + +var ethernet = flag.String("i", "", "interface") +var number = flag.Int("n", 3, "Number of RST packets sent") +var host = flag.String("host", "", "host") +var port = flag.Int("port", 0, "port") +var srcHost = flag.String("shost", "", "src host") +var dstHost = flag.String("dhost", "", "dst host") +var srcPort = flag.Int("sport", 0, "src port") +var dstPort = flag.Int("dport", 0, "dst port") +var timeout = flag.Int("timeout", 0, "timeout") + +func init() { + flag.Parse() + if len(*ethernet) == 0 { + devs, err := pcap.FindAllDevs() + if err != nil { + log.Fatal(err) + } + if len(devs) == 0 { + log.Fatal("interface is not found,please select the interface manually.") + } + *ethernet = devs[0].Name + } +} + +func wall() error { + + fmt.Printf("tcpwall linsten on %v\r\n", *ethernet) + + var handle *pcap.Handle + var err error + if handle, err = pcap.OpenLive(*ethernet, int32(65535), true, -1*time.Second); err != nil { + return err + } + defer handle.Close() + + var filters []string + + if len(*host) > 0 { + filters = append(filters, "host "+*host) + } + + if *port > 0 && *port <= 65535 { + filters = append(filters, "port "+strconv.Itoa(*port)) + } + + if len(*srcHost) > 0 { + filters = append(filters, "src host "+*srcHost) + } + + if *srcPort > 0 && *srcPort <= 65535 { + filters = append(filters, "src port "+strconv.Itoa(*srcPort)) + } + + if len(*dstHost) > 0 { + filters = append(filters, "dst host "+*dstHost) + } + + if *dstPort > 0 && *dstPort <= 65535 { + filters = append(filters, "dst port "+strconv.Itoa(*dstPort)) + } + + if len(filters) == 0 { + log.Fatal("you entered the wrong parameters.") + } + + filter := strings.Join(filters, " and ") + + if err := handle.SetBPFFilter(filter); err != nil { + return err + } + + if len(*srcHost) > 0 && len(*dstHost) > 0 && *srcPort > 0 && *srcPort <= 65535 && *dstPort > 0 && *dstPort <= 65535 { + go func() { + var seq uint32 = 10010 + if err := SendSYN(net.ParseIP(*srcHost), net.ParseIP(*dstHost), layers.TCPPort(*srcPort), layers.TCPPort(*dstPort), seq, handle); err != nil { + log.Fatal(err) + } + + if err := SendSYN(net.ParseIP(*dstHost), net.ParseIP(*srcHost), layers.TCPPort(*dstPort), layers.TCPPort(*srcPort), seq, handle); err != nil { + log.Fatal(err) + } + }() + } + + packetSource := gopacket.NewPacketSource( + handle, + handle.LinkType(), + ) + + if *timeout > 0 { + go func() { + if err := capture(packetSource, handle); err != nil { + log.Fatal(err) + } + }() + + time.Sleep(time.Duration(*timeout) * time.Second) + } else { + if err := capture(packetSource, handle); err != nil { + return err + } + } + + return nil +} + +func capture(packetSource *gopacket.PacketSource, handle *pcap.Handle) error { + for packet := range packetSource.Packets() { + ethLayer := packet.Layer(layers.LayerTypeEthernet) + if ethLayer == nil { + continue + } + eth := ethLayer.(*layers.Ethernet) + ipv4Layer := packet.Layer(layers.LayerTypeIPv4) + if ipv4Layer == nil { + continue + } + ip := ipv4Layer.(*layers.IPv4) + tcpLayer := packet.Layer(layers.LayerTypeTCP) + if tcpLayer == nil { + continue + } + tcp := tcpLayer.(*layers.TCP) + + if tcp.SYN || tcp.FIN || tcp.RST { + continue + } + + for i := 0; i < *number; i++ { + + seq := tcp.Ack + uint32(i)*uint32(tcp.Window) + + err := SendRST(eth.DstMAC, eth.SrcMAC, ip.DstIP, ip.SrcIP, tcp.DstPort, tcp.SrcPort, seq, handle) + if err != nil { + return err + } + } + } + return nil +} + +func SendSYN(srcIp, dstIp net.IP, srcPort, dstPort layers.TCPPort, seq uint32, handle *pcap.Handle) error { + log.Printf("send %v:%v > %v:%v [SYN] seq %v", srcIp.String(), srcPort.String(), dstIp.String(), dstPort.String(), seq) + iPv4 := layers.IPv4{ + SrcIP: srcIp, + DstIP: dstIp, + Version: 4, + TTL: 64, + Protocol: layers.IPProtocolTCP, + } + + tcp := layers.TCP{ + SrcPort: srcPort, + DstPort: dstPort, + Seq: seq, + SYN: true, + } + + if err := tcp.SetNetworkLayerForChecksum(&iPv4); err != nil { + return err + } + + buffer := gopacket.NewSerializeBuffer() + options := gopacket.SerializeOptions{ + FixLengths: true, + ComputeChecksums: true, + } + if err := gopacket.SerializeLayers(buffer, options, &tcp); err != nil { + return err + } + + err := handle.WritePacketData(buffer.Bytes()) + if err != nil { + return err + } + return nil +} + +func SendRST(srcMac, dstMac net.HardwareAddr, srcIp, dstIp net.IP, srcPort, dstPort layers.TCPPort, seq uint32, handle *pcap.Handle) error { + log.Printf("send %v:%v > %v:%v [RST] seq %v", srcIp.String(), srcPort.String(), dstIp.String(), dstPort.String(), seq) + + eth := layers.Ethernet{ + SrcMAC: srcMac, + DstMAC: dstMac, + EthernetType: layers.EthernetTypeIPv4, + } + + iPv4 := layers.IPv4{ + SrcIP: srcIp, + DstIP: dstIp, + Version: 4, + TTL: 64, + Protocol: layers.IPProtocolTCP, + } + + tcp := layers.TCP{ + SrcPort: srcPort, + DstPort: dstPort, + Seq: seq, + RST: true, + } + + if err := tcp.SetNetworkLayerForChecksum(&iPv4); err != nil { + return err + } + + buffer := gopacket.NewSerializeBuffer() + options := gopacket.SerializeOptions{ + FixLengths: true, + ComputeChecksums: true, + } + if err := gopacket.SerializeLayers(buffer, options, ð, &iPv4, &tcp); err != nil { + return err + } + + err := handle.WritePacketData(buffer.Bytes()) + if err != nil { + return err + } + return nil +} + +func main() { + if err := wall(); err != nil { + log.Fatal(err) + } +}