NG_PPPOE(4) BSD Kernel Interfaces Manual NG_PPPOE(4)NAMEng_pppoe — RFC 2516 PPPOE protocol netgraph node type
SYNOPSIS
#include <net/ethernet.h>
#include <netgraph/pppoe/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_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 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_HOOKSIZ]; /* 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.
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);
}
/*
* 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 ALSOnetgraph(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⟩
BSD October 28, 1999 BSD
