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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 4.10                   October 28, 1999                   FreeBSD 4.10

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

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