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NG_PPPOE(4)	       FreeBSD Kernel Interfaces Manual		   NG_PPPOE(4)

NAME
     ng_pppoe -- RFC 2516 PPPOE	protocol netgraph node type

SYNOPSIS
     #include <net/ethernet.h>
     #include <netgraph/ng_pppoe.h>

DESCRIPTION
     The pppoe node type performs the PPPoE protocol. It is used in conjunc-
     tion with the netgraph(4) extensions to the Ethernet framework to divert
     and inject	Ethernet packets to and	from a PPP agent (which	is not speci-
     fied).

     The 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 NGM_TEXT_STATUS control message.

HOOKS
     This node type supports the following hooks:

     ethernet	The hook that should normally be connected to an Ethernet
		node.

     debug	Presently no use.

     [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.

CONTROL	MESSAGES
     This node type supports the generic control messages, plus	the following:

     NGM_PPPOE_GET_STATUS
	  This command returns status information in a struct ngpppoestat:

	      struct ngpppoestat {
		  u_int	  packets_in;	  /* packets in	from ethernet */
		  u_int	  packets_out;	  /* packets out towards ethernet */
	      };

     NGM_TEXT_STATUS
	  This generic message returns is a human-readable version of the node
	  status.  (not	yet)

     NGM_PPPOE_CONNECT
	  Tell a nominated newly created hook that it's	session	should enter
	  the state machine in a manner	to become 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. A session request packet will	be broadcast on	the Ethernet.
	  This command uses the	ngpppoe_init_data structure shown below.

     NGM_PPPOE_LISTEN
	  Tell a nominated newly created hook that it's	session	should enter
	  the state machine in a manner	to become a server listener. The argu-
	  ment given is	the name of the	service	to listen on behalf of.	A zero
	  length service length	will match all requests	for service. A match-
	  ing 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	ngpppoe_init_data structure shown below.

     NGM_PPPOE_OFFER
	  Tell a nominated newly created hook that it's	session	should enter
	  the state machine in a manner	to become 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 ngpppoe_init_data structure shown
	  below.

	  The three commands above use a common	data structure:

	      struct ngpppoe_init_data {
		  char	     hook[NG_HOOKLEN + 1];   /*	hook to	monitor	on */
		  u_int16_t  data_len;		     /*	service	name length */
		  char	     data[0];		     /*	init data goes here */
	      };

     NGM_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 success-
	  ful session.

     NGM_NGM_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

     NGM_NGM_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
	  'failed' message will	be received at closure instead.

	  The three commands above use a common	data structure:

	      struct ngpppoe_sts {
		  char	  hook[NG_HOOKLEN + 1];	/* hook	associated with	event session */
	      };

SHUTDOWN
     This node shuts down upon receipt of a NGM_SHUTDOWN control message, when
     all session have been disconnected	or when	the ethernet hook is discon-
     nected.

SYSCTL VARIABLES
     The variable net.graph.nonstandard_pppoe controls certain aspects of
     ng_pppoe operation.  Its default value of -1 corresponds to standard mode
     and should	suit nearly all	purposes.  A value of 1	will turn on compati-
     bility with some particularly broken PPPoE	implementations	using nonstan-
     dard "ethertypes" in PPPoE	packets.  When in this mode, your PPPoE	node
     will be unable to communicate with	standard nodes.	 A value of 0 is dep-
     recated.  It was intended to turn on autodetection	of the proper mode.
     It	will make your entire PPPoE network vulnerable to a denial-of-service
     attack, therefore its use is strongly discouraged.

EXAMPLES
     The following code	uses libnetgraph to set	up a ng_pppoe node and connect
     it	to both	a socket node and an Ethernet node. It can handle the case of
     when a ng_pppoe node is already attached to the Ethernet. It then starts
     a client session.

     #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_NODELEN + 1];
	     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	     (u_int32_t)
	      *	ninfo->hooks	     (u_int32_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	     (u_int32_t)
		      *	peer->hooks	     (u_int32_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);
	     }
	     /*
	      *	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);
     }

SEE ALSO
     netgraph(3), netgraph(4), ng_ppp(4), ng_socket(4),	ngctl(8)

     L.	Mamakos, K. Lidl, J. Evarts, D.	Carrel,	D. Simone, and R. Wheeler, A
     Method for	transmitting PPP over Ethernet (PPPoE),	RFC 2516.

HISTORY
     The ng_pppoe node type was	implemented in FreeBSD 4.0.

AUTHORS
     Julian Elischer <julian@FreeBSD.org>

FreeBSD	9.2		       October 28, 1999			   FreeBSD 9.2

NAME | SYNOPSIS | DESCRIPTION | HOOKS | CONTROL MESSAGES | SHUTDOWN | SYSCTL VARIABLES | EXAMPLES | SEE ALSO | HISTORY | AUTHORS

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