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NAME

     ng_pppoe - RFC 2516 PPPoE protocol netgraph node type

SYNOPSIS

     #include <sys/types.h>
     #include <net/ethernet.h>
     #include <netgraph.h>
     #include <netgraph/ng_pppoe.h>

DESCRIPTION

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

     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
                    ng_ether(4) node.  Once connected, ng_pppoe 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.

     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 a human-readable version of the node
          status.  (not yet)

     NGM_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
          by its name using the "AC-Name\Service-Name" syntax.  A session
          request packet will be broadcasted on the Ethernet.  This command
          uses the ngpppoe_init_data structure shown below.

     NGM_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 ngpppoe_init_data structure shown below.

     NGM_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 ngpppoe_init_data structure shown
          below.

     The three commands above use a common data structure:

         struct ngpppoe_init_data {
             char       hook[NG_HOOKSIZ];       /* 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
          successful session.

     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_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
          NGM_PPPOE_FAIL message will be received at closure instead.

     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.

     The four commands above use a common data structure:

         struct ngpppoe_sts {
             char    hook[NG_HOOKSIZ];    /* hook associated with event session */
         };

     NGM_PPPOE_GETMODE
          This command returns the current compatibility mode of the node as a
          string.  ASCII form of this message is "pppoe_getmode".  The
          following keywords can be returned:

          "standard"
               The node operates according to RFC 2516.

          "3Com"
               When ng_pppoe 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 ng_pppoe supports both modes simultaneously, depending on
               the ethertype, the client used when connecting.

          "D-Link"
               When ng_pppoe 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.

     NGM_PPPOE_SETMODE
          Configure node to the specified mode.  The string argument is
          required.  This command understands the same keywords that are
          returned by the NGM_PPPOE_GETMODE command.  ASCII form of this
          message is "pppoe_setmode".  For example, the following command will
          configure the node to initiate the next session in the proprietary
          3Com mode:

                ngctl msg fxp0:orphans pppoe_setmode ’"3Com"’

     NGM_PPPOE_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 ethernet hook, or when user wants to override
          this address with another one.  ASCII form of this message is
          "setenaddr".

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
     disconnected.

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_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            (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);
             }

     #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);
     }

SEE ALSO

     netgraph(3), netgraph(4), ng_ether(4), ng_ppp(4), ng_socket(4), ngctl(8),
     ppp(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