diff --git a/THOUGHTS.txt b/THOUGHTS.txt index bf95636..0d4300a 100644 --- a/THOUGHTS.txt +++ b/THOUGHTS.txt @@ -556,3 +556,115 @@ how this thing is installed 19) should we give routeros a hardware ethernet and maybe an l2tp upstream, then we could dogfood the hardware devices. we could run an l2tp service at mythic-beasts, got a /48 there + + +Sat Feb 11 15:57:31 GMT 2023 + +The reason we would like to run PPPoE instead of L2TP on the "rotuer" device is + +- closer to real world scenario +- means no need to run dhcp client on the wan interface before we + even get to start the l2tpd + + +rotuer needs to talk to something (an "access concentrator") that +speaks pppoe on a lan-adjacent machine, which then needs to put the +packets into an l2tp tunnel + +c->s PADI (discovery initiation, broadcast) +s->c PADO (discovery offer) +c->s PADR (discovery request, unicast) +s->c PADS (discovery confirmation, issues SESSION_ID) + +PADT sent at end + +once we have a session id we can send PPP packets. These are +ethernet packets + +6 bytes dest_mac +6 bytes src_mac +2 bytes ether_type = 0x8864 +1 byte ver=1, type=1 (nybbles) +1 bytes CODE = 0x00 +2 bytes sesion_id +2 bytes length +2 bytes PPP protocol = 0xc021 +... ppp payload ... + +pppoe server runs pppd using a pty. it gets input data from an ethernet +device and communicates by sending packets out of that same device to +a remote computer, so what is it doing with that pty? I assume stripping the +ethernet headers and sending the ppp inside it onto pppd + +x2ltpd does the same, so can we hook the ptys together somehow? + +we can ask xl2tpd to open a session using its control socket, but it +will (I assume) spawn a pppd, and what we would like to do is pass file +descriptors to a pppd that already exists. + +xl2tpd has a preprocessor symbol PPPD to specify what it runs + +could we rp-pppoe will + + +it gets data from an ethernet +device with ppp , encapsulation crap and sends it to the pty, then + +ethernet device + +packet with encrap -> rp-pppoe -> pty -> pppd + + +------ + +what if we start from the "other end"? start a l2tp tunnel and session +so that the peer starts sending ppp negotiation. When we get packets +from the peer we will strip the encapsulation and send the inner ppp +payload to pppd as a subprocess on a pty, which will decide how to +respond. The reply is encapsulated and sent out on a port + +for rp-pppoe, the invocation is + + pppd pty 'pppoe [pppoe_options]' [pppd_options] + +i.e. it runs pppd and tells it to use a pppoe process as its pty. +This process accepts ppp packets on stdin/stdout and encapsulates them +for ethernet. + +So, can we use 'pppoe [pppoe_options]' as the pppd argument to xl2tp + +what do we need to test this? + + + +Sun Feb 12 14:57:28 GMT 2023 + +https://github.com/katalix/go-l2tp#kpppoed + + +Mon Feb 13 04:44:09 PM GMT 2023 + +if the gl-ar750 is connected to an ethernet card that linux is ignoring, +we're going to have to set up _some_ qemu thing just to run tftp from. + +Tue Feb 14 17:59:34 GMT 2023 + +We should do a derivation that creates an ISO image and a qemu shell +script based on a configuration.nix, and put it in buildEnv. We'll +call it "borderNetVm" : + +> A broadband remote access server (BRAS, B-RAS or BBRAS) routes + traffic to and from broadband remote access devices such as digital + subscriber line access multiplexers (DSLAM) on an Internet service + provider's (ISP) network.[1][2] BRAS can also be referred to as a + broadband network gateway or border network gateway (BNG).[3] + +(for consistency we should rename the "access" qemu socket network to +match whatever we call this) + +nixos iso-image has a grub label + # A variant to boot with a serial console enabled + LABEL boot-serial + + + rm border.qcow2 ; nix-shell --argstr liminix `pwd` --argstr nixpkgs `pwd`/../nixpkgs --argstr unstable `pwd`/../unstable-nixpkgs/ ci.nix -A buildEnv --run "sudo run-border-vm" diff --git a/default.nix b/default.nix index 910c2e8..db86606 100644 --- a/default.nix +++ b/default.nix @@ -20,6 +20,60 @@ let ./modules/outputs.nix ] pkgs; + borderVm = ((import ) { + configuration = + { config, ... }: + { + imports = [ + + ]; + boot.kernelParams = [ + "loglevel=9" + ]; + systemd.services.pppoe = + let conf = pkgs.writeText "kpppoed.toml" + '' + interface_name = "eth0" + services = [ "myservice" ] + lns_ipaddr = "90.155.53.19" + ac_name = "kpppoed-1.0" + ''; + in { + wantedBy = [ "multi-user.target" ]; + serviceConfig = { + ExecStart = "${pkgs.pkgsBuildBuild.go-l2tp}/bin/kpppoed -config ${conf}"; + }; + }; + virtualisation = { + qemu = { + networkingOptions = []; + options = [ + "-device vfio-pci,host=01:00.0" + "-nographic" + "-serial mon:stdio" + ]; + }; + sharedDirectories = { + liminix = { + source = builtins.toString ./.; + target = "/home/liminix/liminix"; + }; + }; + }; + environment.systemPackages = [ pkgs.pkgsBuildBuild.tufted ]; + security.sudo.wheelNeedsPassword = false; + networking = { + hostName = "border"; + firewall = { enable = false; }; + }; + users.users.liminix = { + isNormalUser = true; + uid = 1000; + extraGroups = [ "wheel"]; + }; + services.getty.autologinUser = "liminix"; + }; + }).config.system; in { outputs = config.outputs // { default = config.outputs.${config.device.defaultOutput}; @@ -35,6 +89,8 @@ in { routeros.routeros routeros.ros-exec-script mips-vm + borderVm.build.vm + go-l2tp ]; }; } diff --git a/modules/phram.nix b/modules/phram.nix index 3cf8060..373aa03 100644 --- a/modules/phram.nix +++ b/modules/phram.nix @@ -16,6 +16,7 @@ in { # the right to change them if I think of better ones. ipaddr = mkOption { type = types.str; }; serverip = mkOption { type = types.str; }; + enable = mkOption { type = types.boolean; }; }; }; }; diff --git a/overlay.nix b/overlay.nix index d1b3294..a477028 100644 --- a/overlay.nix +++ b/overlay.nix @@ -85,5 +85,5 @@ final: prev: { tufted = final.callPackage ./pkgs/tufted {}; routeros = final.callPackage ./pkgs/routeros {}; - + go-l2tp = final.callPackage ./pkgs/go-l2tp {}; } diff --git a/pkgs/go-l2tp/default.nix b/pkgs/go-l2tp/default.nix new file mode 100644 index 0000000..93ab584 --- /dev/null +++ b/pkgs/go-l2tp/default.nix @@ -0,0 +1,19 @@ +{ + buildGoModule +, fetchFromGitHub +}: + +buildGoModule rec { + pname = "go-l2tp"; + version = "0"; + + src = fetchFromGitHub { + repo = "go-l2tp"; + owner = "katalix"; + rev = "570d763"; + hash= "sha256-R8ImKPkPBC+FvzKOBEZ3VxQ12dEjtfRa7AH94xMsAGA="; + }; + doCheck = false; + vendorHash = "sha256-hOkhJhToN/VJwjQmnQJSPGz26/YDR2Ch+1yeW51OF+U="; + +}