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〉