├── .gitignore ├── DEVELOPING.md ├── LICENSE ├── Makefile ├── README.md ├── config.go ├── go.mod ├── go.sum ├── main.go ├── modules ├── example │ ├── example.go │ └── module.go ├── modules.go └── userInterface │ ├── module.go │ └── userInterface.go ├── pndp ├── NDPRequest.go ├── flow.go ├── interface.go ├── interfaceMon.go ├── listener.go ├── netlink.go ├── packet.go ├── packet_test.go ├── responder.go └── util.go ├── pndp_test.sh ├── pndpd.conf └── pndpd.service /.gitignore: -------------------------------------------------------------------------------- 1 | *.iml 2 | .idea 3 | bin/ -------------------------------------------------------------------------------- /DEVELOPING.md: -------------------------------------------------------------------------------- 1 | ## Developing 2 | ### Adding Modules 3 | New functionality should be implemented as a module where possible. You will find an example module under ``modules/example/``. 4 | For additions outside the core functionality you only need to keep the following methods in mind: 5 | ```` 6 | package main 7 | import "pndpd/pndp" 8 | 9 | pndp.ParseFilter(f string) []*net.IPNet 10 | 11 | responderInstance := pndp.NewResponder(iface string, filter []*net.IPNet, autosenseInterface string) 12 | responderInstance.Start() 13 | responderInstance.Stop() 14 | 15 | proxyInstance := pndp.NewProxy(iface1 string, iface2 string, filter []*net.IPNet, autosenseInterface string) 16 | proxyInstance.Start() 17 | proxyInstance.Stop() 18 | ```` 19 | 20 | -------------------------------------------------------------------------------- /LICENSE: -------------------------------------------------------------------------------- 1 | GNU GENERAL PUBLIC LICENSE 2 | Version 3, 29 June 2007 3 | 4 | Copyright (C) 2007 Free Software Foundation, Inc. 5 | Everyone is permitted to copy and distribute verbatim copies 6 | of this license document, but changing it is not allowed. 7 | 8 | Preamble 9 | 10 | The GNU General Public License is a free, copyleft license for 11 | software and other kinds of works. 12 | 13 | The licenses for most software and other practical works are designed 14 | to take away your freedom to share and change the works. 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Limitation of Liability. 601 | 602 | IN NO EVENT UNLESS REQUIRED BY APPLICABLE LAW OR AGREED TO IN WRITING 603 | WILL ANY COPYRIGHT HOLDER, OR ANY OTHER PARTY WHO MODIFIES AND/OR CONVEYS 604 | THE PROGRAM AS PERMITTED ABOVE, BE LIABLE TO YOU FOR DAMAGES, INCLUDING ANY 605 | GENERAL, SPECIAL, INCIDENTAL OR CONSEQUENTIAL DAMAGES ARISING OUT OF THE 606 | USE OR INABILITY TO USE THE PROGRAM (INCLUDING BUT NOT LIMITED TO LOSS OF 607 | DATA OR DATA BEING RENDERED INACCURATE OR LOSSES SUSTAINED BY YOU OR THIRD 608 | PARTIES OR A FAILURE OF THE PROGRAM TO OPERATE WITH ANY OTHER PROGRAMS), 609 | EVEN IF SUCH HOLDER OR OTHER PARTY HAS BEEN ADVISED OF THE POSSIBILITY OF 610 | SUCH DAMAGES. 611 | 612 | 17. 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It is safest 630 | to attach them to the start of each source file to most effectively 631 | state the exclusion of warranty; and each file should have at least 632 | the "copyright" line and a pointer to where the full notice is found. 633 | 634 | 635 | Copyright (C) 636 | 637 | This program is free software: you can redistribute it and/or modify 638 | it under the terms of the GNU General Public License as published by 639 | the Free Software Foundation, either version 3 of the License, or 640 | (at your option) any later version. 641 | 642 | This program is distributed in the hope that it will be useful, 643 | but WITHOUT ANY WARRANTY; without even the implied warranty of 644 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 645 | GNU General Public License for more details. 646 | 647 | You should have received a copy of the GNU General Public License 648 | along with this program. If not, see . 649 | 650 | Also add information on how to contact you by electronic and paper mail. 651 | 652 | If the program does terminal interaction, make it output a short 653 | notice like this when it starts in an interactive mode: 654 | 655 | {{ project }} Copyright (C) {{ year }} {{ organization }} 656 | This program comes with ABSOLUTELY NO WARRANTY; for details type `show w'. 657 | This is free software, and you are welcome to redistribute it 658 | under certain conditions; type `show c' for details. 659 | 660 | The hypothetical commands `show w' and `show c' should show the appropriate 661 | parts of the General Public License. Of course, your program's commands 662 | might be different; for a GUI interface, you would use an "about box". 663 | 664 | You should also get your employer (if you work as a programmer) or school, 665 | if any, to sign a "copyright disclaimer" for the program, if necessary. 666 | For more information on this, and how to apply and follow the GNU GPL, see 667 | . 668 | 669 | The GNU General Public License does not permit incorporating your program 670 | into proprietary programs. If your program is a subroutine library, you 671 | may consider it more useful to permit linking proprietary applications with 672 | the library. If this is what you want to do, use the GNU Lesser General 673 | Public License instead of this License. But first, please read 674 | . -------------------------------------------------------------------------------- /Makefile: -------------------------------------------------------------------------------- 1 | # Makefile for PNDPD 2 | BINARY=pndpd 3 | MODULES= 4 | VERSION=`git describe --tags` 5 | LDFLAGS=-ldflags "-X main.Version=${VERSION} -s -w" 6 | BUILDFLAGS=-trimpath 7 | 8 | build: 9 | go build -tags=${MODULES} -o bin/${BINARY} . 10 | 11 | release: 12 | CGO_ENABLED=0 GOOS=linux go build -tags=${MODULES} ${BUILDFLAGS} ${LDFLAGS} -o bin/${BINARY}_${VERSION}_linux_amd64.bin . 13 | 14 | release-all: 15 | CGO_ENABLED=0 GOOS=linux GOARCH=amd64 go build -tags=${MODULES} ${BUILDFLAGS} ${LDFLAGS} -o bin/${BINARY}_${VERSION}_linux_amd64.bin 16 | CGO_ENABLED=0 GOOS=linux GOARCH=arm64 go build -tags=${MODULES} ${BUILDFLAGS} ${LDFLAGS} -o bin/${BINARY}_${VERSION}_linux_arm64.bin 17 | CGO_ENABLED=0 GOOS=linux GOARCH=arm go build -tags=${MODULES} ${BUILDFLAGS} ${LDFLAGS} -o bin/${BINARY}_${VERSION}_linux_arm.bin 18 | 19 | clean: 20 | if [ -d "bin/" ]; then find bin/ -type f -delete ;fi 21 | if [ -d "bin/" ]; then rm -d bin/ ;fi 22 | -------------------------------------------------------------------------------- /README.md: -------------------------------------------------------------------------------- 1 | # PNDPD - NDP Proxy / Responder (IPv6) 2 | ## Features 3 | - **Efficiently** process incoming packets using bpf (which runs in the kernel) 4 | - **Proxy** NDP between interfaces with an optional whitelist 5 | - Optionally determine whitelist **automatically** based on the IPs assigned to the interfaces 6 | - **Respond** to NDP solicitations for all or only whitelisted addresses on an interface 7 | - Permissions required: root or **CAP_NET_RAW** 8 | - Easily expandable with modules 9 | 10 | ## Installing & Updating 11 | 12 | 1) Download the latest release from the [releases page](https://github.com/Kioubit/pndpd/releases) and move the binary to the ``/usr/local/bin/`` directory under the filename ``pndpd``. 13 | 2) Allow executing the file by running ``chmod +x /usr/local/bin/pndpd`` 14 | 3) Install the systemd service unit file: 15 | ```` 16 | wget https://raw.githubusercontent.com/Kioubit/pndpd/master/pndpd.service -P /etc/systemd/system/ 17 | systemctl enable pndpd.service 18 | ```` 19 | 4) Download and install the config file 20 | ```` 21 | mkdir -p /etc/pndpd 22 | wget https://raw.githubusercontent.com/Kioubit/pndpd/master/pndpd.conf -P /etc/pndpd/ 23 | ```` 24 | 5) Edit the config at ``/etc/pndpd/pndpd.conf`` and then start the service using ``service pndpd start`` 25 | 26 | ## Manual Usage 27 | ```` 28 | pndpd proxy <[optional] 'auto' to determine filters from the internal interface or whitelist of CIDRs separated by a semicolon> 29 | pndpd responder <[optional] 'auto' to determine filters from the external interface or whitelist of CIDRs separated by a semicolon> 30 | pndpd config 31 | ```` 32 | **Example:** ``pndpd proxy eth0 tun0 auto`` 33 | 34 | Find more options and additional documentation in the example config file (``pndpd.conf``). 35 | 36 | ## Example Scenario 37 | ### Proxying NDP requests for a /64 IPv6 subnet on a VPS to a VPN tunnel 38 | 39 | #### 1) Inspecting the initial IP configuration 40 | ```` 41 | root@vultr:~# ip -6 addr show dev enp1s0 42 | 2: enp1s0: mtu 1500 qdisc pfifo_fast state UP group default qlen 1000 43 | inet6 2001:11ff:7400:82f2:5400:4ff:fe53:26cf/64 scope global dynamic mngtmpaddr 44 | valid_lft 2591753sec preferred_lft 604553sec 45 | inet6 fe80::5400:4ff:fe53:26cf/64 scope link 46 | valid_lft forever preferred_lft forever 47 | ```` 48 | As we can see from the output, a `/64` subnet of public IPv6 addresses has been assigned to our VPS on our WAN interface `enp1s0`: 49 | `2001:11ff:7400:82f2:5400:4ff:fe53:26cf/64`. 50 | 51 | #### 2) Routing the subnet to the VPN interface 52 | To route this subnet to our VPN interface `tun0` we need to assign one ip address to the VPS and the rest to the VPN interface. 53 | To do that we edit the `/etc/network/interface` file (for systems that use ifupdown2): 54 | 55 | ##### Initial contents: 56 | ```` 57 | allow-hotplug enp1s0 58 | 59 | iface enp1s0 inet static 60 | #.... IPv4 config here ... 61 | 62 | iface enp1s0 inet6 static 63 | address 2001:11ff:7400:82f2:5400:4ff:fe53:26cf/64 64 | gateway fe80::fc00:4ff:fe53:26cf 65 | ```` 66 | ##### After editing: 67 | ```` 68 | allow-hotplug enp1s0 69 | 70 | iface enp1s0 inet static 71 | #.... IPv4 config here ... 72 | 73 | iface enp1s0 inet6 static 74 | address 2001:11ff:7400:82f2::1/128 75 | gateway fe80::fc00:4ff:fe53:26cf 76 | ```` 77 | On the VPN interface we can now assign the rest of the addresses: 78 | 79 | `ip addr add 2001:11ff:7400:82f2::1/64 dev tun0` 80 | 81 | #### 3) Running PNDPD 82 | To proxy NDP requests from the outside interface to the VPN interface we run pndp like this: 83 | ```` 84 | sudo pndpd proxy enp1s0 tun0 auto 85 | ```` 86 | Note: sudo is not required if you are using the capability as described in the systemd unit file. 87 | Optionally confirm that the setup works via ping and tcpdump. 88 | 89 | ## Building PNDPD 90 | For building, the version of go needs to be installed that is specified in the `go.mod` file. A makefile is available. Optionally adjust the ``MODULES`` variable to include or exclude modules from the "modules" directory. 91 | ```` 92 | make clean; make release 93 | ```` 94 | Find the binaries in the ``bin/`` directory 95 | -------------------------------------------------------------------------------- /config.go: -------------------------------------------------------------------------------- 1 | package main 2 | 3 | import ( 4 | "bufio" 5 | "fmt" 6 | "os" 7 | "pndpd/modules" 8 | "pndpd/pndp" 9 | "strings" 10 | ) 11 | 12 | func readConfig(dest string) { 13 | file, err := os.Open(dest) 14 | if err != nil { 15 | configFatalError(err, "") 16 | } 17 | var ( 18 | currentOption string 19 | blockMap map[string][]string 20 | ) 21 | 22 | scanner := bufio.NewScanner(file) 23 | for scanner.Scan() { 24 | line := scanner.Text() 25 | line, _, _ = strings.Cut(line, "//") 26 | line = strings.TrimSpace(line) 27 | if line == "" { 28 | continue 29 | } 30 | 31 | if after, found := strings.CutPrefix(line, "debug"); found { 32 | if strings.TrimSpace(after) == "on" { 33 | pndp.EnableDebugLog() 34 | } 35 | continue 36 | } 37 | 38 | if option, after, found := strings.Cut(line, "{"); found { 39 | if after != "" { 40 | configFatalError(nil, "Nothing may follow after '{'. A new line must be used") 41 | } 42 | if blockMap != nil { 43 | configFatalError(nil, "A new '{' block was started before the previous one was closed") 44 | } 45 | currentOption = strings.TrimSpace(option) 46 | blockMap = make(map[string][]string) 47 | continue 48 | } 49 | 50 | if before, after, found := strings.Cut(line, "}"); found { 51 | if after != "" || before != "" { 52 | configFatalError(nil, "Nothing may precede or follow '}'. A new line must be used") 53 | } 54 | if blockMap == nil { 55 | configFatalError(nil, "Found a '}' tag without a matching '{' tag.") 56 | } 57 | module, command := modules.GetCommand(currentOption, modules.Config) 58 | if module == nil { 59 | configFatalError(nil, "Unknown configuration block: "+currentOption) 60 | } 61 | modules.ExecuteInit(module, modules.CallbackInfo{ 62 | CallbackType: modules.Config, 63 | Command: command, 64 | Config: blockMap, 65 | }) 66 | blockMap = nil 67 | continue 68 | } 69 | 70 | if blockMap != nil { 71 | kv := strings.SplitN(line, " ", 2) 72 | if len(kv) != 2 { 73 | configFatalError(nil, "Key without value") 74 | } 75 | if blockMap[kv[0]] == nil { 76 | blockMap[kv[0]] = make([]string, 0) 77 | } 78 | blockMap[kv[0]] = append(blockMap[kv[0]], kv[1]) 79 | } 80 | } 81 | _ = file.Close() 82 | 83 | if err := scanner.Err(); err != nil { 84 | configFatalError(err, "") 85 | } 86 | 87 | if modules.ExistsBlockingModule() { 88 | modules.ExecuteComplete() 89 | waitForSignal() 90 | modules.ShutdownAll() 91 | } 92 | } 93 | 94 | func configFatalError(err error, explanation string) { 95 | fmt.Println("Error reading config file:", explanation) 96 | if err != nil { 97 | fmt.Println(err) 98 | } 99 | os.Exit(1) 100 | } 101 | -------------------------------------------------------------------------------- /go.mod: -------------------------------------------------------------------------------- 1 | module pndpd 2 | 3 | go 1.22.5 4 | 5 | require ( 6 | golang.org/x/net v0.27.0 7 | golang.org/x/sys v0.22.0 8 | ) 9 | -------------------------------------------------------------------------------- /go.sum: -------------------------------------------------------------------------------- 1 | golang.org/x/net v0.27.0 h1:5K3Njcw06/l2y9vpGCSdcxWOYHOUk3dVNGDXN+FvAys= 2 | golang.org/x/net v0.27.0/go.mod h1:dDi0PyhWNoiUOrAS8uXv/vnScO4wnHQO4mj9fn/RytE= 3 | golang.org/x/sys v0.22.0 h1:RI27ohtqKCnwULzJLqkv897zojh5/DwS/ENaMzUOaWI= 4 | golang.org/x/sys v0.22.0/go.mod h1:/VUhepiaJMQUp4+oa/7Zr1D23ma6VTLIYjOOTFZPUcA= 5 | -------------------------------------------------------------------------------- /main.go: -------------------------------------------------------------------------------- 1 | package main 2 | 3 | import ( 4 | "fmt" 5 | "os" 6 | "os/signal" 7 | "pndpd/modules" 8 | "syscall" 9 | // Modules 10 | _ "pndpd/modules/example" 11 | _ "pndpd/modules/userInterface" 12 | ) 13 | 14 | var Version = "Custom_Build" 15 | 16 | func main() { 17 | fmt.Println("PNDPD Version", Version, "- Kioubit") 18 | 19 | if len(os.Args) <= 2 { 20 | printUsage() 21 | return 22 | } 23 | 24 | switch os.Args[1] { 25 | case "config": 26 | readConfig(os.Args[2]) 27 | default: 28 | module, command := modules.GetCommand(os.Args[1], modules.CommandLine) 29 | if module != nil { 30 | modules.ExecuteInit(module, modules.CallbackInfo{ 31 | CallbackType: modules.CommandLine, 32 | Command: command, 33 | Arguments: os.Args[2:], 34 | }) 35 | if modules.ExistsBlockingModule() { 36 | modules.ExecuteComplete() 37 | waitForSignal() 38 | modules.ShutdownAll() 39 | } 40 | } else { 41 | printUsage() 42 | } 43 | } 44 | 45 | } 46 | 47 | func printUsage() { 48 | fmt.Println("More options and additional documentation in the example config file") 49 | fmt.Println("Usage:") 50 | fmt.Println("\tpndpd config ") 51 | for i := range modules.ModuleList { 52 | for d := range (*modules.ModuleList[i]).Commands { 53 | if (*modules.ModuleList[i]).Commands[d].CommandLineEnabled { 54 | fmt.Println("\t" + (*modules.ModuleList[i]).Commands[d].Description) 55 | } 56 | } 57 | } 58 | } 59 | 60 | // waitForSignal Waits (blocking) for the program to be interrupted by the OS 61 | func waitForSignal() { 62 | var sigCh = make(chan os.Signal, 1) 63 | signal.Notify(sigCh, os.Interrupt, syscall.SIGTERM) 64 | <-sigCh 65 | signal.Stop(sigCh) 66 | close(sigCh) 67 | } 68 | -------------------------------------------------------------------------------- /modules/example/example.go: -------------------------------------------------------------------------------- 1 | //go:build mod_example 2 | // +build mod_example 3 | 4 | package example 5 | 6 | import ( 7 | "fmt" 8 | "pndpd/modules" 9 | ) 10 | 11 | // This is an example module 12 | func init() { 13 | commands := []modules.Command{{ 14 | CommandText: "pndpd command1", 15 | Description: "This is the usage description for command1", 16 | BlockTerminate: true, 17 | CommandLineEnabled: true, 18 | ConfigEnabled: true, 19 | }, { 20 | CommandText: "pndpd command2", 21 | Description: "This is the usage description for command2", 22 | BlockTerminate: false, 23 | CommandLineEnabled: false, 24 | ConfigEnabled: true, 25 | }, 26 | } 27 | modules.RegisterModule("Example", commands, initCallback, completeCallback, shutdownCallback) 28 | } 29 | 30 | func initCallback(callback modules.CallbackInfo) { 31 | if callback.CallbackType == modules.CommandLine { 32 | // The command registered by the module has been run in the commandline 33 | // "arguments" contains the os.Args[] passed to the program after the command registered by this module 34 | fmt.Println("Command: ", callback.Command.CommandText) 35 | fmt.Println(callback.Arguments) 36 | 37 | } else { 38 | // The command registered by the module was found in the config file 39 | // "arguments" contains the lines between the curly braces 40 | fmt.Println("Command: ", callback.Command.CommandText) 41 | fmt.Println(callback.Arguments) 42 | } 43 | fmt.Println() 44 | } 45 | 46 | func completeCallback() { 47 | //Called after the program has passed all options by calls to initCallback() 48 | } 49 | 50 | func shutdownCallback() { 51 | fmt.Println("Terminate all work") 52 | } 53 | -------------------------------------------------------------------------------- /modules/example/module.go: -------------------------------------------------------------------------------- 1 | package example 2 | -------------------------------------------------------------------------------- /modules/modules.go: -------------------------------------------------------------------------------- 1 | package modules 2 | 3 | var ModuleList []*Module 4 | 5 | type Module struct { 6 | Name string 7 | Commands []Command 8 | InitCallback func(CallbackInfo) 9 | CompleteCallback func() 10 | ShutdownCallback func() 11 | } 12 | 13 | type Command struct { 14 | CommandText string 15 | Description string 16 | BlockTerminate bool 17 | CommandLineEnabled bool 18 | ConfigEnabled bool 19 | } 20 | 21 | type CallbackType int 22 | 23 | const ( 24 | CommandLine CallbackType = 0 25 | Config CallbackType = 1 26 | ) 27 | 28 | type CallbackInfo struct { 29 | CallbackType CallbackType 30 | Command Command 31 | Arguments []string 32 | Config map[string][]string 33 | } 34 | 35 | func RegisterModule(name string, commands []Command, initCallback func(CallbackInfo), CompleteCallback func(), shutdownCallback func()) { 36 | ModuleList = append(ModuleList, &Module{ 37 | Name: name, 38 | Commands: commands, 39 | InitCallback: initCallback, 40 | CompleteCallback: CompleteCallback, 41 | ShutdownCallback: shutdownCallback, 42 | }) 43 | } 44 | 45 | func GetCommand(target string, scope CallbackType) (*Module, Command) { 46 | for i := range ModuleList { 47 | for _, command := range ModuleList[i].Commands { 48 | if command.CommandText == target { 49 | if scope == CommandLine && command.CommandLineEnabled { 50 | return ModuleList[i], command 51 | } 52 | if scope == Config && command.ConfigEnabled { 53 | return ModuleList[i], command 54 | } 55 | return nil, Command{} 56 | } 57 | } 58 | } 59 | return nil, Command{} 60 | } 61 | 62 | var runningModules []*Module 63 | 64 | func ExecuteInit(module *Module, info CallbackInfo) { 65 | if info.Command.BlockTerminate { 66 | found := false 67 | for _, n := range runningModules { 68 | if n == module { 69 | found = true 70 | break 71 | } 72 | } 73 | if !found { 74 | runningModules = append(runningModules, module) 75 | } 76 | } 77 | module.InitCallback(info) 78 | } 79 | 80 | func ExecuteComplete() { 81 | for i := range runningModules { 82 | (*runningModules[i]).CompleteCallback() 83 | } 84 | } 85 | 86 | func ShutdownAll() { 87 | for i := range runningModules { 88 | (*runningModules[i]).ShutdownCallback() 89 | } 90 | } 91 | 92 | func ExistsBlockingModule() bool { 93 | return len(runningModules) != 0 94 | } 95 | -------------------------------------------------------------------------------- /modules/userInterface/module.go: -------------------------------------------------------------------------------- 1 | package userInterface 2 | -------------------------------------------------------------------------------- /modules/userInterface/userInterface.go: -------------------------------------------------------------------------------- 1 | //go:build !noUserInterface 2 | 3 | package userInterface 4 | 5 | import ( 6 | "fmt" 7 | "os" 8 | "pndpd/modules" 9 | "pndpd/pndp" 10 | "strings" 11 | ) 12 | 13 | func init() { 14 | commands := []modules.Command{{ 15 | CommandText: "proxy", 16 | Description: "pndpd proxy <[optional] 'auto' to determine filters from the external interface or whitelist of CIDRs separated by a semicolon>", 17 | BlockTerminate: true, 18 | ConfigEnabled: true, 19 | CommandLineEnabled: true, 20 | }, { 21 | CommandText: "responder", 22 | Description: "pndpd responder <[optional] 'auto' to determine filters from the internal interface or whitelist of CIDRs separated by a semicolon>", 23 | BlockTerminate: true, 24 | ConfigEnabled: true, 25 | CommandLineEnabled: true, 26 | }, { 27 | CommandText: "modules", 28 | Description: "pndpd modules available - list available modules", 29 | BlockTerminate: false, 30 | ConfigEnabled: false, 31 | CommandLineEnabled: true, 32 | }} 33 | modules.RegisterModule("Core", commands, initCallback, completeCallback, shutdownCallback) 34 | } 35 | 36 | type configResponder struct { 37 | Iface string 38 | Filter string 39 | autosense string 40 | DontMonitorInterfaces bool 41 | instance *pndp.ResponderObj 42 | } 43 | 44 | type configProxy struct { 45 | Iface1 string 46 | Iface2 string 47 | Filter string 48 | autosense string 49 | DontMonitorInterfaces bool 50 | instance *pndp.ProxyObj 51 | } 52 | 53 | var allResponders []*configResponder 54 | var allProxies []*configProxy 55 | 56 | func initCallback(callback modules.CallbackInfo) { 57 | if callback.CallbackType == modules.CommandLine { 58 | switch callback.Command.CommandText { 59 | case "proxy": 60 | switch len(callback.Arguments) { 61 | case 3: 62 | var filter = callback.Arguments[2] 63 | var autosense = "" 64 | if callback.Arguments[2] == "auto" { 65 | filter = "" 66 | autosense = callback.Arguments[1] 67 | } 68 | allProxies = append(allProxies, &configProxy{ 69 | Iface1: callback.Arguments[0], 70 | Iface2: callback.Arguments[1], 71 | Filter: filter, 72 | autosense: autosense, 73 | instance: nil, 74 | }) 75 | case 2: 76 | allProxies = append(allProxies, &configProxy{ 77 | Iface1: callback.Arguments[0], 78 | Iface2: callback.Arguments[1], 79 | Filter: "", 80 | autosense: "", 81 | instance: nil, 82 | }) 83 | default: 84 | showError("Invalid syntax") 85 | } 86 | case "responder": 87 | if len(callback.Arguments) == 2 { 88 | var filter = callback.Arguments[1] 89 | var autosense = "" 90 | if callback.Arguments[1] == "auto" { 91 | filter = "" 92 | autosense = callback.Arguments[0] 93 | } 94 | allResponders = append(allResponders, &configResponder{ 95 | Iface: callback.Arguments[0], 96 | Filter: filter, 97 | autosense: autosense, 98 | instance: nil, 99 | }) 100 | } else { 101 | allResponders = append(allResponders, &configResponder{ 102 | Iface: callback.Arguments[0], 103 | Filter: "", 104 | autosense: "", 105 | instance: nil, 106 | }) 107 | } 108 | case "modules": 109 | if modules.ModuleList != nil { 110 | fmt.Print("Available Modules: ") 111 | for i := range modules.ModuleList { 112 | fmt.Print((*modules.ModuleList[i]).Name + " ") 113 | } 114 | fmt.Println() 115 | } 116 | 117 | } 118 | 119 | } else { 120 | switch callback.Command.CommandText { 121 | case "proxy": 122 | obj := configProxy{} 123 | obj.Iface1 = getDefaultConfValue(callback.Config["ext-iface"]) 124 | obj.Iface2 = getDefaultConfValue(callback.Config["int-iface"]) 125 | obj.autosense = getDefaultConfValue(callback.Config["autosense"]) 126 | obj.DontMonitorInterfaces = getDefaultConfValue(callback.Config["monitor-changes"]) == "off" 127 | 128 | filter := "" 129 | for i := range callback.Config["filter"] { 130 | value := callback.Config["filter"][i] 131 | if strings.Contains(value, ";") { 132 | showError("config: the use of semicolons is not allowed in the filter arguments") 133 | } 134 | filter += value + ";" 135 | } 136 | obj.Filter = strings.TrimSuffix(filter, ";") 137 | 138 | if obj.autosense != "" && obj.Filter != "" { 139 | showError("config: cannot have both a filter and autosense enabled on a proxy object") 140 | } 141 | if obj.Iface2 == "" || obj.Iface1 == "" { 142 | showError("config: two interfaces need to be specified in the config file for a proxy object. (ext-iface and int-iface parameters)") 143 | } 144 | allProxies = append(allProxies, &obj) 145 | case "responder": 146 | obj := configResponder{} 147 | obj.Iface = getDefaultConfValue(callback.Config["iface"]) 148 | obj.autosense = getDefaultConfValue(callback.Config["autosense"]) 149 | obj.DontMonitorInterfaces = getDefaultConfValue(callback.Config["monitor-changes"]) == "off" 150 | filter := "" 151 | for i := range callback.Config["filter"] { 152 | value := callback.Config["filter"][i] 153 | if strings.Contains(value, ";") { 154 | showError("config: the use of semicolons is not allowed in the filter arguments") 155 | } 156 | filter += value + ";" 157 | } 158 | obj.Filter = strings.TrimSuffix(filter, ";") 159 | 160 | if obj.autosense != "" && obj.Filter != "" { 161 | showError("config: cannot have both a filter and autosense enabled on a responder object") 162 | } 163 | if obj.Iface == "" { 164 | showError("config: interface not specified in the responder object. (iface parameter)") 165 | } 166 | allResponders = append(allResponders, &obj) 167 | } 168 | } 169 | } 170 | 171 | func getDefaultConfValue(in []string) string { 172 | if in == nil { 173 | return "" 174 | } 175 | if len(in) == 0 { 176 | return "" 177 | } 178 | return in[0] 179 | } 180 | 181 | func completeCallback() { 182 | for _, n := range allProxies { 183 | o := pndp.NewProxy(n.Iface1, n.Iface2, pndp.ParseFilter(n.Filter), n.autosense, !n.DontMonitorInterfaces) 184 | n.instance = o 185 | o.Start() 186 | } 187 | for _, n := range allResponders { 188 | o := pndp.NewResponder(n.Iface, pndp.ParseFilter(n.Filter), n.autosense, !n.DontMonitorInterfaces) 189 | n.instance = o 190 | o.Start() 191 | } 192 | } 193 | 194 | func shutdownCallback() { 195 | for _, n := range allProxies { 196 | n.instance.Stop() 197 | } 198 | 199 | for _, n := range allResponders { 200 | n.instance.Stop() 201 | } 202 | } 203 | 204 | func showError(error string) { 205 | fmt.Println("Error:", error) 206 | fmt.Println("Exiting due to error") 207 | os.Exit(1) 208 | } 209 | -------------------------------------------------------------------------------- /pndp/NDPRequest.go: -------------------------------------------------------------------------------- 1 | package pndp 2 | 3 | type ndpType int 4 | 5 | const ( 6 | ndpAdv ndpType = 0 7 | ndpSol ndpType = 1 8 | ) 9 | 10 | type ndpRequest struct { 11 | requestType ndpType 12 | srcIP []byte 13 | answeringForIP []byte 14 | dstIP []byte 15 | sourceIface string 16 | payload []byte 17 | } 18 | 19 | type ndpQuestion struct { 20 | targetIP []byte 21 | askedBy []byte 22 | } 23 | -------------------------------------------------------------------------------- /pndp/flow.go: -------------------------------------------------------------------------------- 1 | package pndp 2 | 3 | import ( 4 | "fmt" 5 | "net" 6 | "os" 7 | "strings" 8 | "sync" 9 | "time" 10 | ) 11 | 12 | type ResponderObj struct { 13 | stopChan chan struct{} 14 | stopWG *sync.WaitGroup 15 | iface string 16 | filter []*net.IPNet 17 | autosense string 18 | monitorInterfaces bool 19 | } 20 | type ProxyObj struct { 21 | stopChan chan struct{} 22 | stopWG *sync.WaitGroup 23 | iface1 string 24 | iface2 string 25 | filter []*net.IPNet 26 | autosense string 27 | monitorInterfaces bool 28 | } 29 | 30 | // NewResponder 31 | // 32 | // iface - The interface to listen to and respond from 33 | // 34 | // filter - Optional (can be nil) list of IPv6 addresses in CIDR notation to whitelist. Must be IPV6. The ParseFilter function verifies that. 35 | // 36 | // With the optional "autosenseInterface" argument, the whitelist is configured based on the addresses assigned to the interface specified. 37 | // This works even if the IP addresses change frequently. 38 | // 39 | // Start() must be called on the object to actually start responding 40 | func NewResponder(iface string, filter []*net.IPNet, autosenseInterface string, monitorInterfaces bool) *ResponderObj { 41 | if filter == nil && autosenseInterface == "" { 42 | fmt.Println("WARNING: You should use a whitelist for the responder unless you really know what you are doing") 43 | } 44 | checkIsValidNetworkInterfaceFatal(iface, autosenseInterface) 45 | 46 | var s sync.WaitGroup 47 | return &ResponderObj{ 48 | stopChan: make(chan struct{}), 49 | stopWG: &s, 50 | iface: iface, 51 | filter: filter, 52 | autosense: autosenseInterface, 53 | monitorInterfaces: monitorInterfaces, 54 | } 55 | } 56 | func (obj *ResponderObj) Start() { 57 | go obj.start() 58 | } 59 | func (obj *ResponderObj) start() { 60 | obj.stopWG.Add(1) 61 | 62 | startInterfaceMon() 63 | 64 | addInterfaceToMon(obj.iface, obj.monitorInterfaces) 65 | addInterfaceToMon(obj.autosense, true) 66 | 67 | requests := make(chan *ndpRequest, 100) 68 | defer func() { 69 | close(requests) 70 | obj.stopWG.Done() 71 | }() 72 | go respond(obj.iface, requests, ndpAdv, nil, obj.filter, obj.autosense, obj.stopWG, obj.stopChan) 73 | go listen(obj.iface, requests, ndpSol, obj.stopWG, obj.stopChan) 74 | fmt.Printf("Started responder instance on interface %s", obj.iface) 75 | fmt.Println() 76 | <-obj.stopChan 77 | 78 | removeInterfaceFromMon(obj.iface) 79 | removeInterfaceFromMon(obj.autosense) 80 | stopInterfaceMon() 81 | } 82 | 83 | // Stop a running Responder instance 84 | // Returns false on error 85 | func (obj *ResponderObj) Stop() bool { 86 | close(obj.stopChan) 87 | fmt.Println("Shutting down responder instance..") 88 | if wgWaitTimout(obj.stopWG, 10*time.Second) { 89 | fmt.Println("Done") 90 | return true 91 | } else { 92 | fmt.Println("Error shutting down instance") 93 | return false 94 | } 95 | } 96 | 97 | // NewProxy Proxy NDP between interfaces iface1 and iface2 with an optional filter (whitelist) 98 | // 99 | // filter - Optional (can be nil) list of IPv6 addresses in CIDR notation to whitelist. Must be IPV6. The ParseFilter function verifies that. 100 | // 101 | // With the optional "autosenseInterface" argument, the whitelist is configured based on the addresses assigned to the interface specified. 102 | // This works even if the IP addresses change frequently. 103 | // 104 | // Start() must be called on the object to actually start proxying 105 | func NewProxy(iface1 string, iface2 string, filter []*net.IPNet, autosenseInterface string, monitorInterfaces bool) *ProxyObj { 106 | 107 | checkIsValidNetworkInterfaceFatal(iface1, iface2, autosenseInterface) 108 | 109 | var s sync.WaitGroup 110 | return &ProxyObj{ 111 | stopChan: make(chan struct{}), 112 | stopWG: &s, 113 | iface1: iface1, 114 | iface2: iface2, 115 | filter: filter, 116 | autosense: autosenseInterface, 117 | monitorInterfaces: monitorInterfaces, 118 | } 119 | } 120 | 121 | func (obj *ProxyObj) Start() { 122 | go obj.start() 123 | } 124 | func (obj *ProxyObj) start() { 125 | obj.stopWG.Add(1) 126 | defer func() { 127 | obj.stopWG.Done() 128 | }() 129 | 130 | startInterfaceMon() 131 | addInterfaceToMon(obj.iface1, obj.monitorInterfaces) 132 | addInterfaceToMon(obj.iface2, obj.monitorInterfaces) 133 | addInterfaceToMon(obj.autosense, true) 134 | 135 | out_iface1_sol_questions_iface2_adv := make(chan ndpQuestion, 100) 136 | defer close(out_iface1_sol_questions_iface2_adv) 137 | out_iface2_sol_questions_iface1_adv := make(chan ndpQuestion, 100) 138 | defer close(out_iface2_sol_questions_iface1_adv) 139 | 140 | req_iface1_sol_iface2 := make(chan *ndpRequest, 100) 141 | defer close(req_iface1_sol_iface2) 142 | go listen(obj.iface1, req_iface1_sol_iface2, ndpSol, obj.stopWG, obj.stopChan) 143 | go respond(obj.iface2, req_iface1_sol_iface2, ndpSol, out_iface2_sol_questions_iface1_adv, obj.filter, obj.autosense, obj.stopWG, obj.stopChan) 144 | 145 | req_iface2_sol_iface1 := make(chan *ndpRequest, 100) 146 | defer close(req_iface2_sol_iface1) 147 | go listen(obj.iface2, req_iface2_sol_iface1, ndpSol, obj.stopWG, obj.stopChan) 148 | go respond(obj.iface1, req_iface2_sol_iface1, ndpSol, out_iface1_sol_questions_iface2_adv, nil, "", obj.stopWG, obj.stopChan) 149 | 150 | req_iface1_adv_iface2 := make(chan *ndpRequest, 100) 151 | defer close(req_iface1_adv_iface2) 152 | go listen(obj.iface1, req_iface1_adv_iface2, ndpAdv, obj.stopWG, obj.stopChan) 153 | go respond(obj.iface2, req_iface1_adv_iface2, ndpAdv, out_iface1_sol_questions_iface2_adv, nil, "", obj.stopWG, obj.stopChan) 154 | 155 | req_iface2_adv_iface1 := make(chan *ndpRequest, 100) 156 | defer close(req_iface2_adv_iface1) 157 | go listen(obj.iface2, req_iface2_adv_iface1, ndpAdv, obj.stopWG, obj.stopChan) 158 | go respond(obj.iface1, req_iface2_adv_iface1, ndpAdv, out_iface2_sol_questions_iface1_adv, nil, "", obj.stopWG, obj.stopChan) 159 | 160 | fmt.Printf("Started Proxy instance on interfaces %s and %s (if enabled, the whitelist is applied on %s)", obj.iface1, obj.iface2, obj.iface2) 161 | fmt.Println() 162 | <-obj.stopChan 163 | 164 | removeInterfaceFromMon(obj.iface1) 165 | removeInterfaceFromMon(obj.iface2) 166 | removeInterfaceFromMon(obj.autosense) 167 | stopInterfaceMon() 168 | } 169 | 170 | // Stop a running Proxy instance 171 | // Returns false on error 172 | func (obj *ProxyObj) Stop() bool { 173 | close(obj.stopChan) 174 | fmt.Println("Shutting down proxy instance..") 175 | if wgWaitTimout(obj.stopWG, 10*time.Second) { 176 | fmt.Println("Done") 177 | return true 178 | } else { 179 | fmt.Println("Error shutting down instance") 180 | return false 181 | } 182 | } 183 | 184 | // ParseFilter Helper Function to Parse a string of CIDRs separated by a semicolon as a Whitelist 185 | func ParseFilter(f string) []*net.IPNet { 186 | if f == "" { 187 | return nil 188 | } 189 | s := strings.Split(f, ";") 190 | result := make([]*net.IPNet, len(s)) 191 | for i, n := range s { 192 | _, cidr, err := net.ParseCIDR(n) 193 | if err != nil { 194 | showFatalError("filter:", err.Error()) 195 | } 196 | result[i] = cidr 197 | } 198 | return result 199 | } 200 | 201 | func wgWaitTimout(wg *sync.WaitGroup, timeout time.Duration) bool { 202 | t := make(chan struct{}) 203 | go func() { 204 | defer close(t) 205 | wg.Wait() 206 | }() 207 | select { 208 | case <-t: 209 | return true 210 | case <-time.After(timeout): 211 | return false 212 | } 213 | } 214 | 215 | func isValidNetworkInterface(iface string) bool { 216 | if iface == "" { 217 | return true 218 | } 219 | if _, err := net.InterfaceByName(iface); err != nil { 220 | return false 221 | } 222 | return true 223 | } 224 | 225 | func checkIsValidNetworkInterfaceFatal(iface ...string) { 226 | for i := range iface { 227 | if !isValidNetworkInterface(iface[i]) { 228 | showFatalError(fmt.Sprintf("No such network interface \"%s\"", iface[i])) 229 | } 230 | } 231 | } 232 | 233 | func showFatalError(error ...string) { 234 | fmt.Print("Error: ") 235 | for _, err := range error { 236 | fmt.Print(err + " ") 237 | } 238 | fmt.Println() 239 | fmt.Println("Exiting due to error") 240 | os.Exit(1) 241 | } 242 | -------------------------------------------------------------------------------- /pndp/interface.go: -------------------------------------------------------------------------------- 1 | package pndp 2 | 3 | import ( 4 | "net" 5 | "syscall" 6 | "unsafe" 7 | 8 | "golang.org/x/net/bpf" 9 | "golang.org/x/sys/unix" 10 | ) 11 | 12 | // bpfFilter represents a classic BPF filter program that can be applied to a socket 13 | type bpfFilter []bpf.Instruction 14 | 15 | // ApplyTo applies the current filter onto the provided file descriptor 16 | func (filter bpfFilter) ApplyTo(fd int) (err error) { 17 | var assembled []bpf.RawInstruction 18 | if assembled, err = bpf.Assemble(filter); err != nil { 19 | return err 20 | } 21 | 22 | var program = unix.SockFprog{ 23 | Len: uint16(len(assembled)), 24 | Filter: (*unix.SockFilter)(unsafe.Pointer(&assembled[0])), 25 | } 26 | var b = (*[unix.SizeofSockFprog]byte)(unsafe.Pointer(&program))[:unix.SizeofSockFprog] 27 | 28 | if _, _, errno := syscall.Syscall6(syscall.SYS_SETSOCKOPT, 29 | uintptr(fd), uintptr(syscall.SOL_SOCKET), uintptr(syscall.SO_ATTACH_FILTER), 30 | uintptr(unsafe.Pointer(&b[0])), uintptr(len(b)), 0); errno != 0 { 31 | return errno 32 | } 33 | 34 | return nil 35 | } 36 | 37 | type iflags struct { 38 | name [syscall.IFNAMSIZ]byte 39 | flags uint16 40 | } 41 | 42 | func setPromisc(fd int, iface string, enable bool, withInterfaceFlags bool) { 43 | 44 | // -------------------------- Interface flags -------------------------- 45 | if withInterfaceFlags { 46 | tFD, err := syscall.Socket(syscall.AF_INET6, syscall.SOCK_DGRAM, 0) 47 | if err != nil { 48 | showFatalError(err.Error()) 49 | } 50 | 51 | var ifl iflags 52 | copy(ifl.name[:], iface) 53 | _, _, ep := syscall.Syscall(syscall.SYS_IOCTL, uintptr(tFD), syscall.SIOCGIFFLAGS, uintptr(unsafe.Pointer(&ifl))) 54 | if ep != 0 { 55 | showFatalError(ep.Error()) 56 | } 57 | 58 | if enable { 59 | ifl.flags |= uint16(syscall.IFF_PROMISC) 60 | } else { 61 | ifl.flags &^= uint16(syscall.IFF_PROMISC) 62 | } 63 | 64 | _, _, ep = syscall.Syscall(syscall.SYS_IOCTL, uintptr(tFD), syscall.SIOCSIFFLAGS, uintptr(unsafe.Pointer(&ifl))) 65 | if ep != 0 { 66 | showFatalError(ep.Error()) 67 | } 68 | 69 | _ = syscall.Close(tFD) 70 | } 71 | // --------------------------------------------------------------------- 72 | 73 | // -------------------------- Socket Options --------------------------- 74 | iFace, err := net.InterfaceByName(iface) 75 | if err != nil { 76 | showFatalError(err.Error()) 77 | return 78 | } 79 | 80 | mReq := unix.PacketMreq{ 81 | Ifindex: int32(iFace.Index), 82 | Type: unix.PACKET_MR_PROMISC, 83 | } 84 | 85 | var opt int 86 | if enable { 87 | opt = unix.PACKET_ADD_MEMBERSHIP 88 | } else { 89 | opt = unix.PACKET_DROP_MEMBERSHIP 90 | } 91 | 92 | err = unix.SetsockoptPacketMreq(fd, unix.SOL_PACKET, opt, &mReq) 93 | if err != nil { 94 | showFatalError(err.Error()) 95 | } 96 | // --------------------------------------------------------------------- 97 | } 98 | 99 | func selectSourceIP(iface *net.Interface) (gua []byte, ula []byte) { 100 | gua = emptyIpv6 101 | ula = emptyIpv6 102 | interfaceAddresses, err := iface.Addrs() 103 | if err != nil { 104 | return gua, ula 105 | } 106 | 107 | var haveUla = false 108 | var haveGua = false 109 | for _, n := range interfaceAddresses { 110 | if haveGua && haveUla { 111 | break 112 | } 113 | testIP, _, err := net.ParseCIDR(n.String()) 114 | if err != nil { 115 | break 116 | } 117 | if isIpv6(testIP.String()) { 118 | if testIP.IsGlobalUnicast() { 119 | if !ulaSpace.Contains(testIP) { 120 | haveGua = true 121 | gua = testIP 122 | } else { 123 | haveUla = true 124 | ula = testIP 125 | } 126 | } else if testIP.IsLinkLocalUnicast() { 127 | if !haveUla { 128 | ula = testIP 129 | } 130 | if !haveGua { 131 | gua = testIP 132 | } 133 | } 134 | } 135 | } 136 | return gua, ula 137 | } 138 | 139 | func getInterfaceNetworkList(iface *net.Interface) []*net.IPNet { 140 | filter := make([]*net.IPNet, 0) 141 | autoifaceaddrs, err := iface.Addrs() 142 | if err != nil { 143 | return filter 144 | } 145 | for _, l := range autoifaceaddrs { 146 | testIP, anet, err := net.ParseCIDR(l.String()) 147 | if err != nil { 148 | break 149 | } 150 | if isIpv6(testIP.String()) { 151 | filter = append(filter, anet) 152 | } 153 | } 154 | return filter 155 | } 156 | -------------------------------------------------------------------------------- /pndp/interfaceMon.go: -------------------------------------------------------------------------------- 1 | package pndp 2 | 3 | import ( 4 | "net" 5 | "sync" 6 | ) 7 | 8 | var ( 9 | interfaceMonSync sync.Mutex 10 | interfaceMonRunning = false 11 | startCount = 0 12 | wg sync.WaitGroup 13 | s chan interface{} 14 | u chan *interfaceAddressUpdate 15 | ) 16 | 17 | func startInterfaceMon() { 18 | interfaceMonSync.Lock() 19 | defer interfaceMonSync.Unlock() 20 | if !interfaceMonRunning { 21 | interfaceMonRunning = true 22 | u = make(chan *interfaceAddressUpdate, 10) 23 | s = make(chan interface{}) 24 | err := getInterfaceUpdates(u, s) 25 | if err != nil { 26 | showFatalError(err.Error()) 27 | } 28 | go getUpdates() 29 | } 30 | startCount++ 31 | } 32 | 33 | func stopInterfaceMon() { 34 | interfaceMonSync.Lock() 35 | defer interfaceMonSync.Unlock() 36 | startCount-- 37 | if interfaceMonRunning && startCount <= 0 { 38 | if s != nil { 39 | close(s) 40 | wg.Wait() 41 | interfaceMonRunning = false 42 | } 43 | } 44 | } 45 | 46 | func getUpdates() { 47 | wg.Add(1) 48 | for { 49 | update := <-u 50 | if update == nil { 51 | //channel closed 52 | wg.Done() 53 | return 54 | } 55 | if update.NetworkFamily != IPv6 { 56 | continue 57 | } 58 | iface, err := net.InterfaceByIndex(update.InterfaceIndex) 59 | if err != nil { 60 | continue 61 | } 62 | 63 | srcIP, srcIPUla := selectSourceIP(iface) 64 | monMutex.Lock() 65 | 66 | for i := range monInterfaceList { 67 | if monInterfaceList[i].iface.Name == iface.Name { 68 | oldMonIface := monInterfaceList[i] 69 | oldMonIface.sourceIP = srcIP 70 | oldMonIface.sourceIPULA = srcIPUla 71 | if oldMonIface.autosense { 72 | oldMonIface.networks = getInterfaceNetworkList(iface) 73 | } 74 | break 75 | } 76 | } 77 | monMutex.Unlock() 78 | } 79 | } 80 | 81 | type monInterface struct { 82 | addCount int 83 | sourceIP []byte 84 | sourceIPULA []byte 85 | networks []*net.IPNet 86 | iface *net.Interface 87 | autosense bool 88 | } 89 | 90 | var ( 91 | monInterfaceList = make([]*monInterface, 0) 92 | monMutex sync.RWMutex 93 | ) 94 | 95 | func addInterfaceToMon(iface string, autosense bool) { 96 | if iface == "" { 97 | return 98 | } 99 | monMutex.Lock() 100 | defer monMutex.Unlock() 101 | 102 | niface, err := net.InterfaceByName(iface) 103 | if err != nil { 104 | showFatalError(err.Error()) 105 | return 106 | } 107 | 108 | for i := range monInterfaceList { 109 | if monInterfaceList[i].iface.Name == niface.Name { 110 | oldMonIface := monInterfaceList[i] 111 | if autosense { 112 | oldMonIface.autosense = true 113 | } 114 | oldMonIface.addCount++ 115 | return 116 | } 117 | } 118 | newMonIface := &monInterface{ 119 | addCount: 1, 120 | autosense: autosense, 121 | iface: niface, 122 | } 123 | newMonIface.sourceIP, newMonIface.sourceIPULA = selectSourceIP(niface) 124 | newMonIface.networks = getInterfaceNetworkList(niface) 125 | 126 | monInterfaceList = append(monInterfaceList, newMonIface) 127 | } 128 | 129 | func removeInterfaceFromMon(iface string) { 130 | if iface == "" { 131 | return 132 | } 133 | monMutex.Lock() 134 | defer monMutex.Unlock() 135 | niface, err := net.InterfaceByName(iface) 136 | if err != nil { 137 | showFatalError(err.Error()) 138 | return 139 | } 140 | for i := range monInterfaceList { 141 | if monInterfaceList[i].iface.Name == niface.Name { 142 | oldMonIface := monInterfaceList[i] 143 | oldMonIface.addCount-- 144 | if oldMonIface.addCount <= 0 { 145 | monInterfaceList[i] = monInterfaceList[len(monInterfaceList)-1] 146 | monInterfaceList = monInterfaceList[:len(monInterfaceList)-1] 147 | } 148 | return 149 | } 150 | } 151 | } 152 | 153 | func getInterfaceInfo(iface *net.Interface) *monInterface { 154 | ifaceName := iface.Name 155 | monMutex.RLock() 156 | defer monMutex.RUnlock() 157 | for i := range monInterfaceList { 158 | if monInterfaceList[i].iface.Name == ifaceName { 159 | return monInterfaceList[i] 160 | } 161 | } 162 | return nil 163 | } 164 | -------------------------------------------------------------------------------- /pndp/listener.go: -------------------------------------------------------------------------------- 1 | package pndp 2 | 3 | import ( 4 | "bytes" 5 | "errors" 6 | "golang.org/x/net/bpf" 7 | "log/slog" 8 | "net" 9 | "os" 10 | "sync" 11 | "syscall" 12 | ) 13 | 14 | func listen(iface string, responder chan *ndpRequest, requestType ndpType, stopWG *sync.WaitGroup, stopChan chan struct{}) { 15 | stopWG.Add(1) 16 | defer stopWG.Done() 17 | 18 | niface, err := net.InterfaceByName(iface) 19 | if err != nil { 20 | showFatalError(err.Error()) 21 | } 22 | 23 | fd, err := syscall.Socket(syscall.AF_PACKET, syscall.SOCK_RAW|syscall.SOCK_CLOEXEC, htons(syscall.ETH_P_IPV6)) 24 | if err != nil { 25 | showFatalError("Failed setting up listener on interface", iface) 26 | } 27 | 28 | slog.Debug("Obtained fd", "fd", fd) 29 | err = syscall.Bind(fd, &syscall.SockaddrLinklayer{ 30 | Protocol: htons16(syscall.ETH_P_IPV6), 31 | Ifindex: niface.Index, 32 | }) 33 | if err != nil { 34 | showFatalError(err.Error()) 35 | } 36 | slog.Debug("Bound to interface", "fd", fd, "interface", iface) 37 | 38 | setPromisc(fd, iface, true, false) 39 | 40 | var protocolNo uint32 41 | if requestType == ndpSol { 42 | //Neighbor Solicitation 43 | protocolNo = 0x87 44 | } else { 45 | //Neighbor Advertisement 46 | protocolNo = 0x88 47 | } 48 | var f bpfFilter = []bpf.Instruction{ 49 | // Load "EtherType" field from the ethernet header. 50 | bpf.LoadAbsolute{Off: 12, Size: 2}, 51 | // Jump to the drop packet instruction if EtherType is not IPv6. 52 | bpf.JumpIf{Cond: bpf.JumpNotEqual, Val: 0x86dd, SkipTrue: 5}, 53 | // Load "Next Header" field from IPV6 header. 54 | bpf.LoadAbsolute{Off: 20, Size: 1}, 55 | // Jump to the drop packet instruction if Next Header is not ICMPv6. 56 | bpf.JumpIf{Cond: bpf.JumpNotEqual, Val: 0x3a, SkipTrue: 3}, 57 | // Load "Type" field from ICMPv6 header. 58 | bpf.LoadAbsolute{Off: 54, Size: 1}, 59 | // Jump to the drop packet instruction if Type is not Neighbor Solicitation / Advertisement. 60 | bpf.JumpIf{Cond: bpf.JumpNotEqual, Val: protocolNo, SkipTrue: 1}, 61 | // Verdict is: send up to 86 bytes of the packet to userspace. 62 | bpf.RetConstant{Val: 86}, 63 | // Verdict is: "ignore packet." 64 | bpf.RetConstant{Val: 0}, 65 | } 66 | 67 | err = f.ApplyTo(fd) 68 | if err != nil { 69 | showFatalError(err.Error()) 70 | } 71 | 72 | err = syscall.SetNonblock(fd, true) 73 | if err != nil { 74 | slog.Warn("Failed setting nonblock", "fd", fd) 75 | } 76 | 77 | fdN := os.NewFile(uintptr(fd), "") 78 | go func() { 79 | <-stopChan 80 | _ = fdN.Close() 81 | }() 82 | 83 | for { 84 | buf := make([]byte, 86) 85 | numRead, err := fdN.Read(buf) 86 | if err != nil { 87 | if errors.Is(err, os.ErrClosed) { 88 | return 89 | } 90 | showFatalError(err.Error()) 91 | } 92 | 93 | pLogger := slog.Default().With("packet", hexValue{buf[:numRead]}) 94 | 95 | if numRead < 78 { 96 | pLogger.Debug("Dropping packet since it does not meet the minimum length requirement") 97 | continue 98 | } 99 | 100 | if bytes.Equal(buf[6:12], niface.HardwareAddr) { 101 | pLogger.Debug("Dropping packet from ourselves") 102 | continue 103 | } 104 | 105 | if requestType == ndpAdv { 106 | if buf[58] == 0x0 { 107 | pLogger.Debug("Dropping advertisement packet without any NDP flags set") 108 | continue 109 | } 110 | } 111 | 112 | pLogger.Debug("Got packet", "interface", iface, "type", requestType, 113 | "source MAC", macValue{buf[6:12]}, 114 | "source IP", ipValue{buf[22:38]}, 115 | "destination IP", ipValue{buf[38:54]}, 116 | "requested IP", ipValue{buf[62:78]}, 117 | ) 118 | 119 | responder <- &ndpRequest{ 120 | requestType: requestType, 121 | srcIP: buf[22:38], 122 | dstIP: buf[38:54], 123 | answeringForIP: buf[62:78], 124 | payload: buf[54:numRead], 125 | sourceIface: iface, 126 | } 127 | } 128 | } 129 | -------------------------------------------------------------------------------- /pndp/netlink.go: -------------------------------------------------------------------------------- 1 | package pndp 2 | 3 | import ( 4 | "fmt" 5 | "syscall" 6 | "unsafe" 7 | 8 | "golang.org/x/sys/unix" 9 | ) 10 | 11 | type netlinkSocket struct { 12 | fd int 13 | lsa unix.SockaddrNetlink 14 | } 15 | 16 | type interfaceAddressUpdate struct { 17 | InterfaceIndex int 18 | Event addressUpdateInfo 19 | NetworkFamily networkFamily 20 | Flags byte 21 | Scope byte 22 | } 23 | 24 | type networkFamily int 25 | type addressUpdateInfo int 26 | 27 | const ( 28 | IPv4 networkFamily = 4 29 | IPv6 networkFamily = 6 30 | AddressDelete addressUpdateInfo = 0 31 | AddressAdd addressUpdateInfo = 1 32 | ) 33 | 34 | func newNetlinkSocket(protocol int, multicastGroups ...uint) (*netlinkSocket, error) { 35 | fd, err := unix.Socket(unix.AF_NETLINK, unix.SOCK_RAW, protocol) 36 | if err != nil { 37 | return nil, err 38 | } 39 | 40 | socket := &netlinkSocket{} 41 | socket.fd = fd 42 | socket.lsa.Family = unix.AF_NETLINK 43 | 44 | for _, g := range multicastGroups { 45 | socket.lsa.Groups |= 1 << (g - 1) 46 | } 47 | 48 | err = unix.Bind(fd, &socket.lsa) 49 | if err != nil { 50 | _ = unix.Close(fd) 51 | return nil, err 52 | } 53 | return socket, nil 54 | } 55 | 56 | func (socket *netlinkSocket) receiveMessage() ([]syscall.NetlinkMessage, *unix.SockaddrNetlink, error) { 57 | fd := socket.fd 58 | if fd < 0 { 59 | return nil, nil, fmt.Errorf("socket is closed") 60 | } 61 | 62 | var buf [7000]byte 63 | n, from, err := unix.Recvfrom(fd, buf[:], 0) 64 | if err != nil { 65 | return nil, nil, err 66 | } 67 | if n < unix.NLMSG_HDRLEN { 68 | return nil, nil, fmt.Errorf("received a message not meeting the minimum message threshold") 69 | } 70 | read := make([]byte, n) 71 | copy(read, buf[:n]) 72 | 73 | fromAddr, ok := from.(*unix.SockaddrNetlink) 74 | if !ok { 75 | return nil, nil, fmt.Errorf("unable to convert to SockaddrNetlink") 76 | } 77 | 78 | nl, err := syscall.ParseNetlinkMessage(read) 79 | if err != nil { 80 | return nil, nil, err 81 | } 82 | return nl, fromAddr, nil 83 | } 84 | 85 | func (socket *netlinkSocket) Close() { 86 | _ = unix.Close(socket.fd) 87 | socket.fd = -1 88 | } 89 | 90 | func getInterfaceUpdates(updateChannel chan *interfaceAddressUpdate, stopChannel chan interface{}) error { 91 | // Note: UpdateChannel should be buffered 92 | 93 | socket, err := newNetlinkSocket(unix.NETLINK_ROUTE, unix.RTNLGRP_IPV4_IFADDR, unix.RTNLGRP_IPV6_IFADDR) 94 | if err != nil { 95 | return err 96 | } 97 | 98 | if stopChannel != nil { 99 | go func() { 100 | <-stopChannel 101 | socket.Close() 102 | close(updateChannel) 103 | }() 104 | } 105 | go func() { 106 | for { 107 | messages, from, err := socket.receiveMessage() 108 | if err != nil { 109 | //Error receiving 110 | return 111 | } 112 | const kernelPid = 0 113 | if from.Pid != kernelPid { 114 | continue 115 | } 116 | var event addressUpdateInfo 117 | for i := range messages { 118 | switch messages[i].Header.Type { 119 | case unix.NLMSG_DONE: 120 | continue 121 | case unix.NLMSG_ERROR: 122 | continue 123 | case unix.RTM_NEWADDR: 124 | event = AddressAdd 125 | case unix.RTM_DELADDR: 126 | event = AddressDelete 127 | default: 128 | continue 129 | } 130 | 131 | t := messages[i].Data[:unix.SizeofIfAddrmsg] 132 | ifAddrMsgPointer := unsafe.Pointer(&t[0]) 133 | ifAddrMsg := (*unix.IfAddrmsg)(ifAddrMsgPointer) 134 | 135 | var networkFamily networkFamily 136 | switch int(ifAddrMsg.Family) { 137 | case unix.AF_INET: 138 | networkFamily = IPv4 139 | case unix.AF_INET6: 140 | networkFamily = IPv6 141 | default: 142 | continue 143 | } 144 | 145 | update := &interfaceAddressUpdate{} 146 | update.Event = event 147 | update.InterfaceIndex = int(ifAddrMsg.Index) 148 | update.Flags = ifAddrMsg.Flags 149 | update.Scope = ifAddrMsg.Scope 150 | update.NetworkFamily = networkFamily 151 | updateChannel <- update 152 | } 153 | } 154 | }() 155 | return nil 156 | } 157 | -------------------------------------------------------------------------------- /pndp/packet.go: -------------------------------------------------------------------------------- 1 | package pndp 2 | 3 | import ( 4 | "bytes" 5 | "encoding/binary" 6 | "errors" 7 | "log/slog" 8 | "net/netip" 9 | ) 10 | 11 | var emptyIpv6 = []byte{0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0} 12 | var allNodesMulticastIPv6 = []byte{0xFF, 0x01, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0x01} 13 | 14 | type payload interface { 15 | constructPacket() ([]byte, int) 16 | } 17 | 18 | type ipv6Header struct { 19 | protocol byte 20 | srcIP []byte 21 | dstIP []byte 22 | payloadLen []byte 23 | payload []byte 24 | } 25 | 26 | func newIpv6Header(srcIp []byte, dstIp []byte) (*ipv6Header, error) { 27 | if len(dstIp) != 16 || len(srcIp) != 16 { 28 | return nil, errors.New("malformed IP") 29 | } 30 | return &ipv6Header{dstIP: dstIp, srcIP: srcIp, protocol: 0x3a}, nil 31 | } 32 | 33 | func (h *ipv6Header) addPayload(payload payload) { 34 | bPayload, checksumPos := payload.constructPacket() 35 | bPayloadLen := make([]byte, 2) 36 | binary.BigEndian.PutUint16(bPayloadLen, uint16(len(bPayload))) 37 | h.payloadLen = bPayloadLen 38 | 39 | if checksumPos > 0 { 40 | bChecksum := make([]byte, 2) 41 | binary.BigEndian.PutUint16(bChecksum, calculateChecksum(h, bPayload)) 42 | bPayload[checksumPos] = bChecksum[0] 43 | bPayload[checksumPos+1] = bChecksum[1] 44 | } 45 | 46 | h.payload = bPayload 47 | } 48 | 49 | func (h *ipv6Header) constructPacket() []byte { 50 | header := []byte{ 51 | 0x60, // v6 52 | 0, // qos 53 | 0, // qos 54 | 0, // qos 55 | h.payloadLen[0], // payload Length 56 | h.payloadLen[1], // payload Length 57 | h.protocol, // Protocol next header 58 | 0xff, // Hop limit 59 | } 60 | final := append(header, h.srcIP...) 61 | final = append(final, h.dstIP...) 62 | final = append(final, h.payload...) 63 | return final 64 | } 65 | 66 | type ndpPayload struct { 67 | packetType ndpType 68 | answeringForIP []byte 69 | mac []byte 70 | } 71 | 72 | func newNdpPacket(answeringForIP []byte, mac []byte, packetType ndpType) (*ndpPayload, error) { 73 | if len(answeringForIP) != 16 || len(mac) != 6 { 74 | return nil, errors.New("malformed IP") 75 | } 76 | return &ndpPayload{ 77 | packetType: packetType, 78 | answeringForIP: answeringForIP, 79 | mac: mac, 80 | }, nil 81 | } 82 | 83 | func (p *ndpPayload) constructPacket() ([]byte, int) { 84 | var protocol byte 85 | var flags byte 86 | var linkType byte 87 | if p.packetType == ndpSol { 88 | protocol = 0x87 89 | flags = 0x0 90 | linkType = 0x01 91 | } else { 92 | protocol = 0x88 93 | flags = 0x60 94 | linkType = 0x02 95 | } 96 | header := []byte{ 97 | protocol, // Type: ndpType 98 | 0x0, // Code 99 | 0x0, // Checksum filled in later 100 | 0x0, // Checksum filled in later 101 | flags, // Flags (Solicited,Override) 102 | 0x0, // Reserved 103 | 0x0, // Reserved 104 | 0x0, // Reserved 105 | } 106 | final := append(header, p.answeringForIP...) 107 | 108 | secondHeader := []byte{ 109 | linkType, // Type 110 | 0x01, // Length: 1 (8 bytes) 111 | } 112 | final = append(final, secondHeader...) 113 | 114 | final = append(final, p.mac...) 115 | return final, 2 116 | } 117 | 118 | func calculateChecksum(h *ipv6Header, payload []byte) uint16 { 119 | if len(payload) == 0 { 120 | return 0x0000 121 | } 122 | 123 | buf := checksumAddition(h.srcIP, 0) 124 | buf = checksumAddition(h.dstIP, buf) 125 | buf = checksumAddition([]byte{0x00, h.protocol}, buf) 126 | buf = checksumAddition(h.payloadLen, buf) 127 | buf = checksumAddition(payload, buf) 128 | return uint16(buf) ^ 0xFFFF 129 | } 130 | 131 | func checksumAddition(b []byte, buf uint16) uint16 { 132 | var sum = uint32(buf) 133 | cv := len(b) - 1 134 | for i := 0; i < cv; i += 2 { 135 | sum += uint32(uint16(b[i])<<8 | uint16(b[i+1])) 136 | } 137 | if cv&1 == 0 { 138 | sum += uint32(uint16(b[cv])<<8 | uint16(0x00)) 139 | } 140 | 141 | for sum>>16 > 0x0 { 142 | sum = (sum & 0xffff) + (sum >> 16) 143 | } 144 | return uint16(sum) 145 | } 146 | 147 | func checkPacketChecksum(v6 *ipv6Header, payload []byte) bool { 148 | packetsum := make([]byte, 2) 149 | copy(packetsum, payload[2:4]) 150 | 151 | bPayloadLen := make([]byte, 2) 152 | binary.BigEndian.PutUint16(bPayloadLen, uint16(len(payload))) 153 | v6.payloadLen = bPayloadLen 154 | 155 | payload[2] = 0x0 156 | payload[3] = 0x0 157 | 158 | bChecksum := make([]byte, 2) 159 | binary.BigEndian.PutUint16(bChecksum, calculateChecksum(v6, payload)) 160 | if bytes.Equal(packetsum, bChecksum) { 161 | return true 162 | } else { 163 | slog.Debug("Received packet checksum validation failed", "payload", hexValue{payload}, 164 | "v6SrcIP", hexValue{v6.srcIP}, 165 | "v6DstIP", hexValue{v6.dstIP}, 166 | ) 167 | return false 168 | } 169 | } 170 | 171 | func isIpv6(ip string) bool { 172 | testIp, err := netip.ParseAddr(ip) 173 | if err != nil { 174 | return false 175 | } 176 | return testIp.Is6() 177 | } 178 | -------------------------------------------------------------------------------- /pndp/packet_test.go: -------------------------------------------------------------------------------- 1 | package pndp 2 | 3 | import ( 4 | "bytes" 5 | "encoding/binary" 6 | "encoding/hex" 7 | "strings" 8 | "testing" 9 | ) 10 | 11 | func TestCalculateChecksum(t *testing.T) { 12 | //fd00::251d:bbbb:bbbb:bbbb → ff02::1:ff00:99 ICMPv6 Neighbor Solicitation for fd00::99 from ad:ad:ad:ad:ad:ad 13 | 14 | type testCase struct { 15 | payloadHexString string 16 | want []byte 17 | } 18 | 19 | cases := []testCase{ 20 | {"87 00 1D 12 00 00 00 00 FD 00 00 00 00 00 00 00 00 00 00 00 00 00 00 99 01 01 AD AD AD AD AD AD", //32 (Even) 21 | []byte{0x1D, 0x12}}, 22 | {"87 00 1D 12 00 00 00 00 FD 00 00 00 00 00 00 00 00 00 00 00 00 00 00 99 01 01 AD AD AD AD AD", //31 (Not even) 23 | []byte{0x1D, 0xC0}}, 24 | } 25 | 26 | testSrcIP := []byte{0xFD, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x25, 0x1D, 0xBB, 0xBB, 0xBB, 0xBB, 0xBB, 0xBB} 27 | testDstIP := []byte{0xFF, 0x02, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01, 0xFF, 0x00, 0x00, 0x99} 28 | testHeader, _ := newIpv6Header(testSrcIP, testDstIP) 29 | 30 | for _, tc := range cases { 31 | payloadBytes, err := hex.DecodeString(strings.Join(strings.Fields(tc.payloadHexString), "")) 32 | if err != nil { 33 | t.Errorf("%s", err) 34 | } 35 | 36 | bPayloadLen := make([]byte, 2) 37 | binary.BigEndian.PutUint16(bPayloadLen, uint16(len(payloadBytes))) 38 | testHeader.payloadLen = bPayloadLen 39 | 40 | // Clear existing checksum as it should be zero for calculation 41 | payloadBytes[2] = 0x0 42 | payloadBytes[3] = 0x0 43 | 44 | got := calculateChecksum(testHeader, payloadBytes) 45 | 46 | bChecksum := make([]byte, 2) 47 | binary.BigEndian.PutUint16(bChecksum, got) 48 | if !bytes.Equal(tc.want, bChecksum) { 49 | t.Errorf("Expected '%x', but got '%x'", tc.want, bChecksum) 50 | } 51 | } 52 | } 53 | 54 | func TestCheckPacketChecksum(t *testing.T) { 55 | type testCase struct { 56 | payloadHexString string 57 | want bool 58 | } 59 | 60 | cases := []testCase{ 61 | {"87 00 1D 12 00 00 00 00 FD 00 00 00 00 00 00 00 00 00 00 00 00 00 00 99 01 01 AD AD AD AD AD AD", //32 (Even) 62 | true}, 63 | {"87 00 1D 12 00 00 00 00 FD 00 00 00 00 00 00 00 00 00 00 00 00 00 00 99 01 01 AD AD AD AD AD", //31 (Not even) 64 | false}, 65 | } 66 | 67 | testSrcIP := []byte{0xFD, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x25, 0x1D, 0xBB, 0xBB, 0xBB, 0xBB, 0xBB, 0xBB} 68 | testDstIP := []byte{0xFF, 0x02, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01, 0xFF, 0x00, 0x00, 0x99} 69 | testHeader, _ := newIpv6Header(testSrcIP, testDstIP) 70 | 71 | for _, tc := range cases { 72 | payloadBytes, err := hex.DecodeString(strings.Join(strings.Fields(tc.payloadHexString), "")) 73 | if err != nil { 74 | t.Errorf("%s", err) 75 | } 76 | got := checkPacketChecksum(testHeader, payloadBytes) 77 | if tc.want != got { 78 | t.Errorf("Excpected valid: '%t', but got valid: '%t' with payload '%x'", tc.want, got, payloadBytes) 79 | } 80 | 81 | } 82 | } 83 | 84 | func TestIsIpv6(t *testing.T) { 85 | type testCase struct { 86 | ip string 87 | want bool 88 | } 89 | cases := []testCase{ 90 | {"0.0.0.0", false}, 91 | {"fd", false}, 92 | {"fd::", true}, 93 | {"fd00::", true}, 94 | } 95 | 96 | for _, tc := range cases { 97 | if isIpv6(tc.ip) != tc.want { 98 | t.Errorf("Expected '%t', but got '%t' for %s", tc.want, !tc.want, tc.ip) 99 | } 100 | } 101 | 102 | } 103 | -------------------------------------------------------------------------------- /pndp/responder.go: -------------------------------------------------------------------------------- 1 | package pndp 2 | 3 | import ( 4 | "bytes" 5 | "log/slog" 6 | "net" 7 | "sync" 8 | "syscall" 9 | ) 10 | 11 | func respond(iface string, requests chan *ndpRequest, respondType ndpType, ndpQuestionChan chan ndpQuestion, filter []*net.IPNet, autoSense string, stopWG *sync.WaitGroup, stopChan chan struct{}) { 12 | stopWG.Add(1) 13 | defer stopWG.Done() 14 | 15 | var autoiface *net.Interface 16 | if autoSense != "" { 17 | var err error 18 | autoiface, err = net.InterfaceByName(autoSense) 19 | if err != nil { 20 | showFatalError(err.Error()) 21 | } 22 | } 23 | 24 | var ndpQuestionsList = make([]ndpQuestion, 0, 40) 25 | var _, linkLocalSpace, _ = net.ParseCIDR("fe80::/10") 26 | 27 | fd, err := syscall.Socket(syscall.AF_INET6, syscall.SOCK_RAW|syscall.SOCK_CLOEXEC, syscall.IPPROTO_RAW) 28 | if err != nil { 29 | showFatalError(err.Error()) 30 | } 31 | defer func(fd int) { 32 | _ = syscall.Close(fd) 33 | }(fd) 34 | slog.Debug("Obtained fd", "fd", fd) 35 | 36 | err = syscall.BindToDevice(fd, iface) 37 | if err != nil { 38 | showFatalError(err.Error()) 39 | } 40 | slog.Debug("Bound to interface", "fd", fd, "interface", iface) 41 | 42 | respondIface, err := net.InterfaceByName(iface) 43 | if err != nil { 44 | showFatalError(err.Error()) 45 | } 46 | 47 | for { 48 | var req *ndpRequest 49 | if (ndpQuestionChan == nil && respondType == ndpAdv) || (ndpQuestionChan != nil && respondType == ndpSol) { 50 | select { 51 | case <-stopChan: 52 | return 53 | case req = <-requests: 54 | } 55 | } else { 56 | // This is if ndpQuestionChan != nil && respondType == ndp_ADV 57 | select { 58 | case <-stopChan: 59 | return 60 | case q := <-ndpQuestionChan: 61 | ndpQuestionsList = append(ndpQuestionsList, q) 62 | ndpQuestionsList = cleanupQuestionList(ndpQuestionsList) 63 | continue 64 | case req = <-requests: 65 | } 66 | } 67 | 68 | v6Header, err := newIpv6Header(req.srcIP, req.dstIP) 69 | if err != nil { 70 | continue 71 | } 72 | if !checkPacketChecksum(v6Header, req.payload) { 73 | continue 74 | } 75 | 76 | if linkLocalSpace.Contains(req.answeringForIP) { 77 | slog.Debug("Dropping packet asking for a link-local IP") 78 | continue 79 | } 80 | 81 | // Auto-sense 82 | if autoSense != "" { 83 | filter = getInterfaceInfo(autoiface).networks 84 | } 85 | 86 | if filter != nil { 87 | ok := false 88 | for _, i := range filter { 89 | if i.Contains(req.answeringForIP) { 90 | slog.Debug("Responding for whitelisted IP", "ip", ipValue{req.answeringForIP}) 91 | ok = true 92 | break 93 | } 94 | } 95 | if !ok { 96 | continue 97 | } 98 | } 99 | 100 | intInfo := getInterfaceInfo(respondIface) 101 | var selectedSelfSourceIPGua = intInfo.sourceIP 102 | var selectedSelfSourceIPUla = intInfo.sourceIPULA 103 | var selectedSelfSourceIP = selectedSelfSourceIPGua 104 | if ulaSpace.Contains(req.answeringForIP) { 105 | selectedSelfSourceIP = selectedSelfSourceIPUla 106 | } 107 | 108 | if req.sourceIface == iface { 109 | slog.Debug("Sending packet", "type", respondType, "dest", ipValue{req.dstIP}, "interface", respondIface.Name) 110 | sendNDPPacket(fd, req.dstIP, req.srcIP, req.answeringForIP, respondIface.HardwareAddr, respondType) 111 | } else { 112 | if respondType == ndpAdv { 113 | if !bytes.Equal(req.dstIP, allNodesMulticastIPv6) { // Skip in case of unsolicited advertisement 114 | success := false 115 | req.dstIP, success = getAddressFromQuestionList(req.answeringForIP, &ndpQuestionsList) 116 | if !success { 117 | slog.Debug("Nobody has asked for this IP", "ip", ipValue{req.answeringForIP}) 118 | continue 119 | } 120 | } 121 | } else { 122 | if bytes.Equal(req.srcIP, emptyIpv6) { 123 | // Duplicate Address detection is in progress 124 | selectedSelfSourceIP = emptyIpv6 125 | } else { 126 | ndpQuestionChan <- ndpQuestion{ 127 | targetIP: req.answeringForIP, 128 | askedBy: req.srcIP, 129 | } 130 | } 131 | } 132 | slog.Debug("Sending packet", "type", respondType, "dest", ipValue{req.dstIP}, "interface", respondIface.Name) 133 | 134 | sendNDPPacket(fd, selectedSelfSourceIP, req.dstIP, req.answeringForIP, respondIface.HardwareAddr, respondType) 135 | } 136 | } 137 | } 138 | 139 | func sendNDPPacket(fd int, ownIP []byte, dstIP []byte, ndpTargetIP []byte, ndpTargetMac []byte, ndpType ndpType) { 140 | v6, err := newIpv6Header(ownIP, dstIP) 141 | if err != nil { 142 | return 143 | } 144 | NDPa, err := newNdpPacket(ndpTargetIP, ndpTargetMac, ndpType) 145 | if err != nil { 146 | return 147 | } 148 | v6.addPayload(NDPa) 149 | packet := v6.constructPacket() 150 | 151 | var t [16]byte 152 | copy(t[:], dstIP) 153 | 154 | err = syscall.Sendto(fd, packet, 0, &syscall.SockaddrInet6{ 155 | Addr: t, 156 | }) 157 | if err != nil { 158 | slog.Error("Error sending packet", "error", err) 159 | } 160 | } 161 | 162 | func getAddressFromQuestionList(targetIP []byte, ndpQuestionsList *[]ndpQuestion) ([]byte, bool) { 163 | for i := range *ndpQuestionsList { 164 | if bytes.Equal((*ndpQuestionsList)[i].targetIP, targetIP) { 165 | result := (*ndpQuestionsList)[i].askedBy 166 | *ndpQuestionsList = removeFromQuestionList(*ndpQuestionsList, i) 167 | return result, true 168 | } 169 | } 170 | return nil, false 171 | } 172 | func removeFromQuestionList(s []ndpQuestion, i int) []ndpQuestion { 173 | // Remove while keeping the order 174 | return append(s[:i], s[i+1:]...) 175 | } 176 | 177 | func cleanupQuestionList(s []ndpQuestion) []ndpQuestion { 178 | toRemove := len(s) - 40 179 | if toRemove <= 0 { 180 | return s 181 | } 182 | return s[toRemove:] 183 | } 184 | -------------------------------------------------------------------------------- /pndp/util.go: -------------------------------------------------------------------------------- 1 | package pndp 2 | 3 | import ( 4 | "fmt" 5 | "log/slog" 6 | "net" 7 | "net/netip" 8 | "os" 9 | ) 10 | 11 | func EnableDebugLog() { 12 | slog.SetDefault(slog.New(slog.NewTextHandler(os.Stdout, &slog.HandlerOptions{Level: slog.LevelDebug, AddSource: true}))) 13 | } 14 | 15 | type hexValue struct { 16 | arg []byte 17 | } 18 | 19 | func (v hexValue) LogValue() slog.Value { 20 | return slog.StringValue(fmt.Sprintf("%X", v.arg)) 21 | } 22 | 23 | type ipValue struct { 24 | arg []byte 25 | } 26 | 27 | func (v ipValue) LogValue() slog.Value { 28 | if len(v.arg) != 16 { 29 | return slog.StringValue(fmt.Sprintf("%X", v.arg)) 30 | } 31 | return slog.StringValue(netip.AddrFrom16([16]byte(v.arg)).String()) 32 | } 33 | 34 | type macValue struct { 35 | arg []byte 36 | } 37 | 38 | func (v macValue) LogValue() slog.Value { 39 | if len(v.arg) != 6 { 40 | return slog.StringValue(fmt.Sprintf("%X", v.arg)) 41 | } 42 | return slog.StringValue(fmt.Sprintf("%X:%X:%X:%X:%X:%X", v.arg[0], v.arg[1], v.arg[2], v.arg[3], v.arg[4], v.arg[5])) 43 | } 44 | 45 | // Htons Convert a uint16 to host byte order (big endian) 46 | func htons(v uint16) int { return int(htons16(v)) } 47 | func htons16(v uint16) uint16 { return (v << 8) | (v >> 8) } 48 | 49 | var _, ulaSpace, _ = net.ParseCIDR("fc00::/7") 50 | -------------------------------------------------------------------------------- /pndp_test.sh: -------------------------------------------------------------------------------- 1 | #!/usr/bin/env sh 2 | set -euxo 3 | 4 | make 5 | 6 | ip netns add pndpd-p # Provider 7 | ip netns exec pndpd-p sysctl -w net.ipv6.conf.all.forwarding=1 8 | ip netns add pndpd-c # Client 9 | ip netns exec pndpd-c sysctl -w net.ipv6.conf.all.forwarding=1 10 | ip netns add pndpd-i # Inner client 11 | ip netns exec pndpd-i sysctl -w net.ipv6.conf.all.forwarding=1 12 | 13 | # Provider bridge 14 | ip -netns pndpd-p link add br0 type bridge 15 | ip -netns pndpd-p addr add fd00::/62 dev br0 16 | ip -netns pndpd-p addr add 2001:db8::/62 dev br0 17 | ip -netns pndpd-p link set dev br0 address 00:00:00:00:00:01 # Predictable link-local 18 | ip -netns pndpd-p link set up dev br0 19 | 20 | # Client 0 link to provider bridge 21 | ip -netns pndpd-p link add veth-c0 type veth peer name veth-p 22 | ip -netns pndpd-p link set up veth-c0 23 | ip -netns pndpd-p link set veth-c0 master br0 24 | 25 | ip -netns pndpd-p link set veth-p netns pndpd-c 26 | ip -netns pndpd-c addr add fd00:0:0:1::/128 dev veth-p 27 | ip -netns pndpd-c addr add 2001:db8:0:1::/128 dev veth-p 28 | ip -netns pndpd-c link set up dev veth-p 29 | ip -netns pndpd-c route add default via fe80::200:ff:fe00:1 dev veth-p 30 | 31 | # Bridge on client 0 32 | ip -netns pndpd-c link add br0 type bridge 33 | ip -netns pndpd-c addr add fd00:0:0:1::/64 dev br0 34 | ip -netns pndpd-c addr add 2001:db8:0:1::/64 dev br0 35 | ip -netns pndpd-c link set dev br0 address 00:00:00:00:00:02 36 | ip -netns pndpd-c link set up dev br0 37 | 38 | # Inner client link to client 0 bridge 39 | ip -netns pndpd-c link add veth-i0 type veth peer name veth-c 40 | ip -netns pndpd-c link set up veth-i0 41 | ip -netns pndpd-c link set veth-i0 master br0 42 | 43 | ip -netns pndpd-c link set veth-c netns pndpd-i 44 | ip -netns pndpd-i addr add fd00:0:0:1::100/64 dev veth-c 45 | ip -netns pndpd-i addr add 2001:db8:0:1::100/64 dev veth-c 46 | ip -netns pndpd-i link set up dev veth-c 47 | ip -netns pndpd-i route add default via fd00:0:0:1:: dev veth-c 48 | 49 | sleep 2 50 | ip netns exec pndpd-c bin/pndpd proxy veth-p br0 auto & 51 | PID=$! 52 | sleep 2 53 | 54 | # Perform tests 55 | ip netns exec pndpd-p ping -c 5 -w 10 fd00:0:0:1::100 56 | ip netns exec pndpd-p ping -c 5 -w 10 2001:db8:0:1::100 57 | 58 | kill -n 2 "$PID" 59 | wait 60 | echo "Tests successful" 61 | 62 | # Teardown 63 | ip netns delete pndpd-p 64 | ip netns delete pndpd-c 65 | ip netns delete pndpd-i -------------------------------------------------------------------------------- /pndpd.conf: -------------------------------------------------------------------------------- 1 | // Example config file for PNDPD 2 | 3 | // Proxy example with autoconfigured allow-list 4 | // The allow-list of IP addresses to proxy is configured based 5 | // on the networks assigned to the interface specified via the autosense parameter. 6 | // This works even if the IP addresses change frequently. 7 | proxy { 8 | ext-iface eth0 9 | int-iface eth1 10 | autosense eth1 // If eth1 has fd01::1/64 assigned to it, then fd01::/64 will be configured as an allow-list 11 | // Disable monitor-changes only if the IP addresses assigned to the specified interfaces never change (with the exception of the autosense interface) 12 | // monitor-changes on 13 | } 14 | 15 | // Proxy example with a static allow-list 16 | // Create an NDP proxy for proxying NDP between the external ext-iface ("eth0") and the internal int-iface ("eth1") 17 | // Note that you can remove the filter lines to disable address checking completely (not recommended) 18 | proxy { 19 | ext-iface eth0 20 | int-iface eth1 21 | filter fd01::/64 22 | filter fd02::/64 23 | // Disable monitor-changes only if the IP addresses assigned to the specified interfaces never change 24 | // monitor-changes on 25 | } 26 | 27 | 28 | // Responder example with autoconfigured allow-list (Not recommended - prefer using proxy mode) 29 | // Create an NDP responder that listens and responds on interface "eth0" 30 | // The allow-list of IP addresses to proxy is configured based 31 | // on the networks assigned to the interface specified via the autosense parameter. 32 | // This works even if the IP addresses change frequently. 33 | responder { 34 | iface eth0 35 | autosense eth0 // If eth0 has fd01::1/64 assigned to it, then fd01::/64 will be configured as an allow-list 36 | // Disable monitor-changes only if the IP addresses assigned to the specified interfaces never change (with the exception of the autosense interface) 37 | // monitor-changes on 38 | } 39 | 40 | // Responder example with a static allow-list (Not recommended - prefer using proxy mode) 41 | // Create an NDP responder that listens and responds on interface "eth0" 42 | // Note that you can remove the filter lines to disable address checking completely (not recommended) 43 | responder { 44 | iface eth0 45 | filter fd01::/64 46 | filter fd02::/64 47 | // Disable monitor-changes only if the IP addresses assigned to the specified interfaces never change 48 | // monitor-changes on 49 | } 50 | 51 | // Enable or disable debug output 52 | // If enabled, this option can fill up system logfiles very quickly 53 | // debug off 54 | -------------------------------------------------------------------------------- /pndpd.service: -------------------------------------------------------------------------------- 1 | [Unit] 2 | Description=Proxy NDP Daemon 3 | Wants=network-online.target 4 | After=network.target network-online.target 5 | 6 | [Service] 7 | Type=simple 8 | Restart=on-failure 9 | RestartSec=5s 10 | ExecStart=/usr/local/bin/pndpd config /etc/pndpd/pndpd.conf 11 | 12 | DynamicUser=yes 13 | AmbientCapabilities=CAP_NET_RAW CAP_NET_ADMIN 14 | CapabilityBoundingSet=CAP_NET_RAW CAP_NET_ADMIN 15 | ProtectHome=yes 16 | 17 | [Install] 18 | WantedBy=multi-user.target --------------------------------------------------------------------------------