man/man4/ng_pppoe.4

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.\" Author: Archie Cobbs <archie@FreeBSD.org>
.\" $Whistle: ng_pppoe.8,v 1.1 1999/01/25 23:46:27 archie Exp $
.\"
.Dd May 1, 2022
.Dt NG_PPPOE 4
.Os
.Sh NAME
.Nm ng_pppoe
.Nd RFC 2516 PPPoE protocol netgraph node type
.Sh SYNOPSIS
.In sys/types.h
.In net/ethernet.h
.In netgraph.h
.In netgraph/ng_pppoe.h
.Sh DESCRIPTION
The
.Nm pppoe
node type performs the PPPoE protocol.
It is used in conjunction with the
.Xr netgraph 4
extensions to the Ethernet framework to divert and inject Ethernet packets
to and from a PPP agent (which is not specified).
.Pp
The
.Dv NGM_PPPOE_GET_STATUS
control message can be used at any time to query the current status
of the PPPoE module.
The only statistics presently available are the
total packet counts for input and output.
This node does not yet support
the
.Dv NGM_TEXT_STATUS
control message.
.Sh HOOKS
This node type supports the following hooks:
.Bl -tag -width ".Va [unspecified]"
.It Va ethernet
The hook that should normally be connected to an
.Xr ng_ether 4
node.
Once connected,
.Nm
will send a message down this hook to determine Ethernet address of
the underlying node.
Obtained address will be stored and then used for outgoing datagrams.
.It Va debug
Presently no use.
.It Va [unspecified]
Any other name is assumed to be a session hook that will be connected to
a PPP client agent, or a PPP server agent.
.El
.Sh CONTROL MESSAGES
This node type supports the generic control messages, plus the following:
.Bl -tag -width 3n
.It Dv NGM_PPPOE_GET_STATUS
This command returns status information in a
.Dv "struct ngpppoestat" :
.Bd -literal -offset 4n
struct ngpppoestat {
    u_int   packets_in;     /* packets in from Ethernet */
    u_int   packets_out;    /* packets out towards Ethernet */
};
.Ed
.It Dv NGM_TEXT_STATUS
This generic message returns a human-readable version of the node status.
(not yet)
.It Dv NGM_PPPOE_CONNECT Pq Ic pppoe_connect
Tell a nominated newly created hook that its session should enter
the state machine as a client.
It must be newly created and a service name can be given as an argument.
It is legal to specify a zero-length service name, this is common
on some DSL setups.
It is possible to request a connection to a specific access concentrator,
and/or set a specific Host-Uniq tag, required by some Internet providers,
using the
.Qq Li [AC-Name\\][Host-Uniq|]Service-Name
syntax.
To set a binary Host-Uniq, it must be encoded as a hexadecimal lowercase
string and prefixed with
.Qq Li 0x ,
for example
.Qq Li 0x6d792d746167
is equivalent to
.Qq Li my-tag .
A session request packet will be broadcast on the Ethernet.
This command uses the
.Dv ngpppoe_init_data
structure shown below.
For example, this init data argument can be used to
connect to
.Qq Li my-isp
service with
.Qq Li my-host
uniq tag, accepting only
.Qq Li remote-ac
as access concentrator:
.Bd -literal -offset indent
"remote-ac\\my-host|my-isp"
.Ed
.It Dv NGM_PPPOE_LISTEN Pq Ic pppoe_listen
Tell a nominated newly created hook that its session should enter
the state machine as a server listener.
The argument
given is the name of the service to listen for.
A zero-length service name will match all requests for service.
A matching service request
packet will be passed unmodified back to the process responsible
for starting the service.
It can then examine it and pass it on to
the session that is started to answer the request.
This command uses the
.Dv ngpppoe_init_data
structure shown below.
.It Dv NGM_PPPOE_OFFER Pq Ic pppoe_offer
Tell a nominated newly created hook that its session should enter
the state machine as a server.
The argument given is the name of the service to offer.
A zero-length service
is legal.
The State machine will progress to a state where it will await
a request packet to be forwarded to it from the startup server,
which in turn probably received it from a LISTEN mode hook (see above).
This is so
that information that is required for the session that is embedded in
the original session request packet, is made available to the state machine
that eventually answers the request.
When the Session request packet is
received, the session negotiation will proceed.
This command uses the
.Dv ngpppoe_init_data
structure shown below.
.El
.Pp
The three commands above use a common data structure:
.Bd -literal -offset 4n
struct ngpppoe_init_data {
    char       hook[NG_HOOKSIZ];       /* hook to monitor on */
    uint16_t   data_len;               /* length of the service name */
    char       data[0];                /* init data goes here */
};
.Ed
.Bl -tag -width 3n
.It Dv NGM_PPPOE_SUCCESS Pq Ic pppoe_success
This command is sent to the node that started this session with one of the
above messages, and reports a state change.
This message reports successful Session negotiation.
It uses the structure shown below, and
reports back the hook name corresponding to the successful session.
.It Dv NGM_PPPOE_FAIL Pq Ic pppoe_fail
This command is sent to the node that started this session with one of the
above messages, and reports a state change.
This message reports failed Session negotiation.
It uses the structure shown below, and
reports back the hook name corresponding to the failed session.
The hook will probably have been removed immediately after sending this
message.
.It Dv NGM_PPPOE_CLOSE Pq Ic pppoe_close
This command is sent to the node that started this session with one of the
above messages, and reports a state change.
This message reports a request to close a session.
It uses the structure shown below, and
reports back the hook name corresponding to the closed session.
The hook will probably have been removed immediately after sending this
message.
At present this message is not yet used and a
.Dv NGM_PPPOE_FAIL
message
will be received at closure instead.
.It Dv NGM_PPPOE_ACNAME
This command is sent to the node that started this session with one of the
above messages, and reports the Access Concentrator Name.
.El
.Pp
The four commands above use a common data structure:
.Bd -literal -offset 4n
struct ngpppoe_sts {
    char    hook[NG_HOOKSIZ];
};
.Ed
.Bl -tag -width 3n
.It Dv NGM_PPPOE_GETMODE Pq Ic pppoe_getmode
This command returns the current compatibility mode of the node
as a string.
.Tn ASCII
form of this message is
.Qq Li pppoe_getmode .
The following keywords can be returned:
.Bl -tag -width 3n
.It Qq standard
The node operates according to RFC 2516.
.It Qq 3Com
When
.Nm
is a PPPoE client, it initiates a session encapsulating packets into
incorrect 3Com ethertypes.
This compatibility option does not affect server mode.
In server mode
.Nm
supports both modes simultaneously, depending on the ethertype, the
client used when connecting.
.It Qq D-Link
When
.Nm
is a PPPoE server serving only specific Service-Name(s), it will respond
to a PADI requests with empty Service-Name tag, returning all available
Service-Name(s) on node.
This option is necessary for compatibility with D-Link DI-614+ and DI-624+
SOHO routers as clients, when serving only specific Service-Name.
This compatibility option does not affect client mode.
.El
.It Dv NGM_PPPOE_SETMODE Pq Ic pppoe_setmode
Configure node to the specified mode.
The string argument is required.
This command understands the same keywords that are returned by the
.Dv NGM_PPPOE_GETMODE
command.
.Tn ASCII
form of this message is
.Qq Li pppoe_setmode .
For example, the following command will configure the node to initiate
the next session in the proprietary 3Com mode:
.Bd -literal -offset indent
ngctl msg fxp0:orphans pppoe_setmode '"3Com"'
.Ed
.It Dv NGM_PPPOE_SETENADDR Pq Ic setenaddr
Set the node Ethernet address for outgoing datagrams.
This message is important when a node has failed to obtain an Ethernet
address from its peer on the
.Dv ethernet
hook, or when user wants to override this address with another one.
.Tn ASCII
form of this message is
.Qq Li setenaddr .
.It Dv NGM_PPPOE_SETMAXP Pq Ic setmaxp
Set the node PPP-Max-Payload value as described in RFC 4638.
This message applies only to a client configuration.
.Tn ASCII
form of this message is
.Qq Li setmaxp .
.Pp
Data structure returned to client is:
.Bd -literal -offset 4n
struct ngpppoe_maxp {
    char     hook[NG_HOOKSIZ];
    uint16_t data;
};
.Ed
.It Dv NGM_PPPOE_SEND_HURL Pq Ic send_hurl
Tell a nominated hook with an active session to send a PADM message with
a HURL tag.
The argument is the URL to be delivered to the client:
.Bd -literal -offset indent
ngctl msg fxp0:orphans send_hurl '{ hook="myHook" data="http://example.net/cpe" }'
.Ed
.It Dv NGM_PPPOE_SEND_MOTM Pq Ic send_motm
Tell a nominated hook with an active session to send a PADM message with
a MOTM tag.
The argument is the message to be delivered to the client:
.Bd -literal -offset indent
ngctl msg fxp0:orphans send_motm '{ hook="myHook" data="Welcome aboard" }'
.Ed
.El
.Pp
The two commands above use the same ngpppoe_init_data structure described
above.
.Bl -tag -width 3n
.It Dv NGM_PPPOE_HURL
This command is sent to the node that started this session when a PADM
message with a HURL tag is received, and contains a URL that the host can
pass to a web browser for presentation to the user.
.It Dv NGM_PPPOE_MOTM
This command is sent to the node that started this session when a PADM
message with a MOTM tag is received, and contains a Message Of The
Minute that the host can display to the user.
.El
.Pp
The two commands above use a common data structure:
.Bd -literal -offset 4n
struct ngpppoe_padm {
    char    msg[PPPOE_PADM_VALUE_SIZE];
};
.Ed
.Sh SHUTDOWN
This node shuts down upon receipt of a
.Dv NGM_SHUTDOWN
control message, when all session have been disconnected or when the
.Dv ethernet
hook is disconnected.
.Sh SYSCTL VARIABLES
The node can mark transmitted LCP Ethernet packets (protocol 0xc021)
with 3-bit Priority Code Point (PCP) referring to IEEE 802.1p
class of service with following
.Xr sysctl 8
variable.
.Bl -tag -width indent
.It Va net.graph.pppoe.lcp_pcp: 0..7 (default: 0)
Set it to non-zero value to be used by parent network interface driver
like
.Xr vlan 4
.El
.Sh EXAMPLES
The following code uses
.Dv libnetgraph
to set up a
.Nm
node and connect it to both a socket node and an Ethernet node.
It can handle the case of when a
.Nm
node is already attached to the Ethernet.
It then starts a client session.
.Bd -literal
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <ctype.h>
#include <unistd.h>
#include <sysexits.h>
#include <errno.h>
#include <err.h>

#include <sys/types.h>
#include <sys/socket.h>
#include <sys/select.h>
#include <net/ethernet.h>

#include <netgraph.h>
#include <netgraph/ng_ether.h>
#include <netgraph/ng_pppoe.h>
#include <netgraph/ng_socket.h>
static int setup(char *ethername, char *service, char *sessname,
				int *dfd, int *cfd);

int
main()
{
	int  fd1, fd2;
	setup("xl0", NULL, "fred", &fd1, &fd2);
	sleep (30);
}

static int
setup(char *ethername, char *service, char *sessname,
			int *dfd, int *cfd)
{
	struct ngm_connect ngc;	/* connect */
	struct ngm_mkpeer mkp;	/* mkpeer */
	/******** nodeinfo stuff **********/
	u_char          rbuf[2 * 1024];
	struct ng_mesg *const resp = (struct ng_mesg *) rbuf;
	struct hooklist *const hlist
			= (struct hooklist *) resp->data;
	struct nodeinfo *const ninfo = &hlist->nodeinfo;
	int             ch, no_hooks = 0;
	struct linkinfo *link;
	struct nodeinfo *peer;
	/****message to connect PPPoE session*****/
	struct {
		struct ngpppoe_init_data idata;
		char            service[100];
	}               message;
	/********tracking our little graph ********/
	char            path[100];
	char            source_ID[NG_NODESIZ];
	char            pppoe_node_name[100];
	int             k;

	/*
	 * Create the data and control sockets
	 */
	if (NgMkSockNode(NULL, cfd, dfd) < 0) {
		return (errno);
	}
	/*
	 * find the ether node of the name requested by asking it for
	 * it's inquiry information.
	 */
	if (strlen(ethername) > 16)
		return (EINVAL);
	sprintf(path, "%s:", ethername);
	if (NgSendMsg(*cfd, path, NGM_GENERIC_COOKIE,
		      NGM_LISTHOOKS, NULL, 0) < 0) {
		return (errno);
	}
	/*
	 * the command was accepted so it exists. Await the reply (It's
	 * almost certainly already waiting).
	 */
	if (NgRecvMsg(*cfd, resp, sizeof(rbuf), NULL) < 0) {
		return (errno);
	}
	/**
	 * The following is available about the node:
	 * ninfo->name		(string)
	 * ninfo->type		(string)
	 * ninfo->id		(uint32_t)
	 * ninfo->hooks		(uint32_t) (count of hooks)
	 * check it is the correct type. and get it's ID for use
	 * with mkpeer later.
	 */
	if (strncmp(ninfo->type, NG_ETHER_NODE_TYPE,
		    strlen(NG_ETHER_NODE_TYPE)) != 0) {
		return (EPROTOTYPE);
	}
	sprintf(source_ID, "[%08x]:", ninfo->id);

	/*
	 * look for a hook already attached.
	 */
	for (k = 0; k < ninfo->hooks; k++) {
		/**
		 * The following are available about each hook.
		 * link->ourhook	(string)
		 * link->peerhook	(string)
		 * peer->name		(string)
		 * peer->type		(string)
		 * peer->id		(uint32_t)
		 * peer->hooks		(uint32_t)
		 */
		link = &hlist->link[k];
		peer = &hlist->link[k].nodeinfo;

		/* Ignore debug hooks */
		if (strcmp("debug", link->ourhook) == 0)
			continue;

		/* If the orphans hook is attached, use that */
		if (strcmp(NG_ETHER_HOOK_ORPHAN,
		    link->ourhook) == 0) {
			break;
		}
		/* the other option is the 'divert' hook */
		if (strcmp("NG_ETHER_HOOK_DIVERT",
		    link->ourhook) == 0) {
			break;
		}
	}

	/*
	 * See if we found a hook there.
	 */
	if (k < ninfo->hooks) {
		if (strcmp(peer->type, NG_PPPOE_NODE_TYPE) == 0) {
			/*
			 * If it's a type PPPoE, we skip making one
			 * ourself, but we continue, using
			 * the existing one.
			 */
			sprintf(pppoe_node_name, "[%08x]:", peer->id);
		} else {
			/*
			 * There is already someone hogging the data,
			 * return an error. Some day we'll try
			 * daisy-chaining..
			 */
			return (EBUSY);
		}
	} else {

		/*
		 * Try make a node of type PPPoE against node "ID"
		 * On hook NG_ETHER_HOOK_ORPHAN.
		 */
		snprintf(mkp.type, sizeof(mkp.type),
			 "%s", NG_PPPOE_NODE_TYPE);
		snprintf(mkp.ourhook, sizeof(mkp.ourhook),
			 "%s", NG_ETHER_HOOK_ORPHAN);
		snprintf(mkp.peerhook, sizeof(mkp.peerhook),
			 "%s", NG_PPPOE_HOOK_ETHERNET);
		/* Send message */
		if (NgSendMsg(*cfd, source_ID, NGM_GENERIC_COOKIE,
			      NGM_MKPEER, &mkp, sizeof(mkp)) < 0) {
			return (errno);
		}
		/*
		 * Work out a name for the new node.
		 */
		sprintf(pppoe_node_name, "%s:%s",
			source_ID, NG_ETHER_HOOK_ORPHAN);
	}
	/*
	 * We now have a PPPoE node attached to the Ethernet
	 * card. The Ethernet is addressed as ethername: The PPPoE
	 * node is addressed as pppoe_node_name: attach to it.
	 * Connect socket node to specified node Use the same hook
	 * name on both ends of the link.
	 */
	snprintf(ngc.path, sizeof(ngc.path), "%s", pppoe_node_name);
	snprintf(ngc.ourhook, sizeof(ngc.ourhook), "%s", sessname);
	snprintf(ngc.peerhook, sizeof(ngc.peerhook), "%s", sessname);

	if (NgSendMsg(*cfd, ".:", NGM_GENERIC_COOKIE,
		      NGM_CONNECT, &ngc, sizeof(ngc)) < 0) {
		return (errno);
	}

#ifdef	NONSTANDARD
	/*
	 * In some cases we are speaking to 3Com hardware, so
	 * configure node to non-standard mode.
	 */
	if (NgSendMsg(*cfd, ngc.path, NGM_PPPOE_COOKIE,
			NGM_PPPOE_SETMODE, NG_PPPOE_NONSTANDARD,
			strlen(NG_PPPOE_NONSTANDARD) + 1) == -1) {
		return (errno);
	}
#endif

	/*
	 * Send it a message telling it to start up.
	 */
	bzero(&message, sizeof(message));
	snprintf(message.idata.hook, sizeof(message.idata.hook),
				"%s", sessname);
	if (service == NULL) {
		message.idata.data_len = 0;
	} else {
		snprintf(message.idata.data,
			 sizeof(message.idata.data), "%s", service);
		message.idata.data_len = strlen(service);
	}
	/* Tell session/hook to start up as a client */
	if (NgSendMsg(*cfd, ngc.path,
		      NGM_PPPOE_COOKIE, NGM_PPPOE_CONNECT, &message.idata,
		      sizeof(message.idata) + message.idata.data_len) < 0) {
		return (errno);
	}
	return (0);
}
.Ed
.Sh SEE ALSO
.Xr netgraph 3 ,
.Xr netgraph 4 ,
.Xr ng_ether 4 ,
.Xr ng_ppp 4 ,
.Xr ng_socket 4 ,
.Xr ngctl 8 ,
.Xr ppp 8 ,
.Xr vlan 4
.Rs
.%A L. Mamakos
.%A K. Lidl
.%A J. Evarts
.%A D. Carrel
.%A D. Simone
.%A R. Wheeler
.%T "A Method for transmitting PPP over Ethernet (PPPoE)"
.%O RFC 2516
.Re
.Sh HISTORY
The
.Nm
node type was implemented in
.Fx 4.0 .
.Sh AUTHORS
.An Julian Elischer Aq Mt julian@FreeBSD.org