FreeBSD-5.3/sys/netgraph/ng_frame_relay.c
/*
* ng_frame_relay.c
*
* Copyright (c) 1996-1999 Whistle Communications, Inc.
* All rights reserved.
*
* Subject to the following obligations and disclaimer of warranty, use and
* redistribution of this software, in source or object code forms, with or
* without modifications are expressly permitted by Whistle Communications;
* provided, however, that:
* 1. Any and all reproductions of the source or object code must include the
* copyright notice above and the following disclaimer of warranties; and
* 2. No rights are granted, in any manner or form, to use Whistle
* Communications, Inc. trademarks, including the mark "WHISTLE
* COMMUNICATIONS" on advertising, endorsements, or otherwise except as
* such appears in the above copyright notice or in the software.
*
* THIS SOFTWARE IS BEING PROVIDED BY WHISTLE COMMUNICATIONS "AS IS", AND
* TO THE MAXIMUM EXTENT PERMITTED BY LAW, WHISTLE COMMUNICATIONS MAKES NO
* REPRESENTATIONS OR WARRANTIES, EXPRESS OR IMPLIED, REGARDING THIS SOFTWARE,
* INCLUDING WITHOUT LIMITATION, ANY AND ALL IMPLIED WARRANTIES OF
* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, OR NON-INFRINGEMENT.
* WHISTLE COMMUNICATIONS DOES NOT WARRANT, GUARANTEE, OR MAKE ANY
* REPRESENTATIONS REGARDING THE USE OF, OR THE RESULTS OF THE USE OF THIS
* SOFTWARE IN TERMS OF ITS CORRECTNESS, ACCURACY, RELIABILITY OR OTHERWISE.
* IN NO EVENT SHALL WHISTLE COMMUNICATIONS BE LIABLE FOR ANY DAMAGES
* RESULTING FROM OR ARISING OUT OF ANY USE OF THIS SOFTWARE, INCLUDING
* WITHOUT LIMITATION, ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY,
* PUNITIVE, OR CONSEQUENTIAL DAMAGES, PROCUREMENT OF SUBSTITUTE GOODS OR
* SERVICES, LOSS OF USE, DATA OR PROFITS, HOWEVER CAUSED AND UNDER ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
* THIS SOFTWARE, EVEN IF WHISTLE COMMUNICATIONS IS ADVISED OF THE POSSIBILITY
* OF SUCH DAMAGE.
*
* Author: Julian Elischer <julian@freebsd.org>
*
* $FreeBSD: src/sys/netgraph/ng_frame_relay.c,v 1.23 2004/07/12 04:35:42 rwatson Exp $
* $Whistle: ng_frame_relay.c,v 1.20 1999/11/01 09:24:51 julian Exp $
*/
/*
* This node implements the frame relay protocol, not including
* the LMI line management. This means basically keeping track
* of which DLCI's are active, doing frame (de)multiplexing, etc.
*
* It has a 'downstream' hook that goes to the line, and a
* hook for each DLCI (eg, 'dlci16').
*/
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/kernel.h>
#include <sys/errno.h>
#include <sys/malloc.h>
#include <sys/mbuf.h>
#include <sys/syslog.h>
#include <sys/ctype.h>
#include <netgraph/ng_message.h>
#include <netgraph/netgraph.h>
#include <netgraph/ng_frame_relay.h>
/*
* Line info, and status per channel.
*/
struct ctxinfo { /* one per active hook */
u_int flags;
#define CHAN_VALID 0x01 /* assigned to a channel */
#define CHAN_ACTIVE 0x02 /* bottom level active */
int dlci; /* the dlci assigned to this context */
hook_p hook; /* if there's a hook assigned.. */
};
#define MAX_CT 16 /* # of dlci's active at a time (POWER OF 2!) */
struct frmrel_softc {
int unit; /* which card are we? */
int datahooks; /* number of data hooks attached */
node_p node; /* netgraph node */
int addrlen; /* address header length */
int flags; /* state */
int mtu; /* guess */
u_char remote_seq; /* sequence number the remote sent */
u_char local_seq; /* sequence number the remote rcvd */
u_short ALT[1024]; /* map DLCIs to CTX */
#define CTX_VALID 0x8000 /* this bit means it's a valid CTX */
#define CTX_VALUE (MAX_CT - 1) /* mask for context part */
struct ctxinfo channel[MAX_CT];
struct ctxinfo downstream;
};
typedef struct frmrel_softc *sc_p;
#define BYTEX_EA 0x01 /* End Address. Always 0 on byte1 */
#define BYTE1_C_R 0x02
#define BYTE2_FECN 0x08 /* forwards congestion notification */
#define BYTE2_BECN 0x04 /* Backward congestion notification */
#define BYTE2_DE 0x02 /* Discard elligability */
#define LASTBYTE_D_C 0x02 /* last byte is dl_core or dlci info */
/* Used to do headers */
const static struct segment {
u_char mask;
u_char shift;
u_char width;
} makeup[] = {
{ 0xfc, 2, 6 },
{ 0xf0, 4, 4 },
{ 0xfe, 1, 7 },
{ 0xfc, 2, 6 }
};
#define SHIFTIN(segment, byte, dlci) \
{ \
(dlci) <<= (segment)->width; \
(dlci) |= \
(((byte) & (segment)->mask) >> (segment)->shift); \
}
#define SHIFTOUT(segment, byte, dlci) \
{ \
(byte) |= (((dlci) << (segment)->shift) & (segment)->mask); \
(dlci) >>= (segment)->width; \
}
/* Netgraph methods */
static ng_constructor_t ngfrm_constructor;
static ng_shutdown_t ngfrm_shutdown;
static ng_newhook_t ngfrm_newhook;
static ng_rcvdata_t ngfrm_rcvdata;
static ng_disconnect_t ngfrm_disconnect;
/* Other internal functions */
static int ngfrm_decode(node_p node, item_p item);
static int ngfrm_addrlen(char *hdr);
static int ngfrm_allocate_CTX(sc_p sc, int dlci);
/* Netgraph type */
static struct ng_type typestruct = {
.version = NG_ABI_VERSION,
.name = NG_FRAMERELAY_NODE_TYPE,
.constructor = ngfrm_constructor,
.shutdown = ngfrm_shutdown,
.newhook = ngfrm_newhook,
.rcvdata = ngfrm_rcvdata,
.disconnect = ngfrm_disconnect,
};
NETGRAPH_INIT(framerelay, &typestruct);
/*
* Given a DLCI, return the index of the context table entry for it,
* Allocating a new one if needs be, or -1 if none available.
*/
static int
ngfrm_allocate_CTX(sc_p sc, int dlci)
{
u_int ctxnum = -1; /* what ctx number we are using */
volatile struct ctxinfo *CTXp = NULL;
/* Sanity check the dlci value */
if (dlci > 1023)
return (-1);
/* Check to see if we already have an entry for this DLCI */
if (sc->ALT[dlci]) {
if ((ctxnum = sc->ALT[dlci] & CTX_VALUE) < MAX_CT) {
CTXp = sc->channel + ctxnum;
} else {
ctxnum = -1;
sc->ALT[dlci] = 0; /* paranoid but... */
}
}
/*
* If the index has no valid entry yet, then we need to allocate a
* CTX number to it
*/
if (CTXp == NULL) {
for (ctxnum = 0; ctxnum < MAX_CT; ctxnum++) {
/*
* If the VALID flag is empty it is unused
*/
if ((sc->channel[ctxnum].flags & CHAN_VALID) == 0) {
bzero(sc->channel + ctxnum,
sizeof(struct ctxinfo));
CTXp = sc->channel + ctxnum;
sc->ALT[dlci] = ctxnum | CTX_VALID;
sc->channel[ctxnum].dlci = dlci;
sc->channel[ctxnum].flags = CHAN_VALID;
break;
}
}
}
/*
* If we still don't have a CTX pointer, then we never found a free
* spot so give up now..
*/
if (!CTXp) {
log(LOG_ERR, "No CTX available for dlci %d\n", dlci);
return (-1);
}
return (ctxnum);
}
/*
* Node constructor
*/
static int
ngfrm_constructor(node_p node)
{
sc_p sc;
MALLOC(sc, sc_p, sizeof(*sc), M_NETGRAPH, M_NOWAIT | M_ZERO);
if (!sc)
return (ENOMEM);
sc->addrlen = 2; /* default */
/* Link the node and our private info */
NG_NODE_SET_PRIVATE(node, sc);
sc->node = node;
return (0);
}
/*
* Add a new hook
*
* We allow hooks called "debug", "downstream" and dlci[0-1023]
* The hook's private info points to our stash of info about that
* channel. A NULL pointer is debug and a DLCI of -1 means downstream.
*/
static int
ngfrm_newhook(node_p node, hook_p hook, const char *name)
{
const sc_p sc = NG_NODE_PRIVATE(node);
const char *cp;
char *eptr;
int dlci = 0;
int ctxnum;
/* Check if it's our friend the control hook */
if (strcmp(name, NG_FRAMERELAY_HOOK_DEBUG) == 0) {
NG_HOOK_SET_PRIVATE(hook, NULL); /* paranoid */
return (0);
}
/*
* All other hooks either start with 'dlci' and have a decimal
* trailing channel number up to 4 digits, or are the downstream
* hook.
*/
if (strncmp(name, NG_FRAMERELAY_HOOK_DLCI,
strlen(NG_FRAMERELAY_HOOK_DLCI)) != 0) {
/* It must be the downstream connection */
if (strcmp(name, NG_FRAMERELAY_HOOK_DOWNSTREAM) != 0)
return EINVAL;
/* Make sure we haven't already got one (paranoid) */
if (sc->downstream.hook)
return (EADDRINUSE);
/* OK add it */
NG_HOOK_SET_PRIVATE(hook, &sc->downstream);
sc->downstream.hook = hook;
sc->downstream.dlci = -1;
sc->downstream.flags |= CHAN_ACTIVE;
sc->datahooks++;
return (0);
}
/* Must be a dlci hook at this point */
cp = name + strlen(NG_FRAMERELAY_HOOK_DLCI);
if (!isdigit(*cp) || (cp[0] == '0' && cp[1] != '\0'))
return (EINVAL);
dlci = (int)strtoul(cp, &eptr, 10);
if (*eptr != '\0' || dlci < 0 || dlci > 1023)
return (EINVAL);
/*
* We have a dlci, now either find it, or allocate it. It's possible
* that we might have seen packets for it already and made an entry
* for it.
*/
ctxnum = ngfrm_allocate_CTX(sc, dlci);
if (ctxnum == -1)
return (ENOBUFS);
/*
* Be paranoid: if it's got a hook already, that dlci is in use .
* Generic code can not catch all the synonyms (e.g. dlci016 vs
* dlci16)
*/
if (sc->channel[ctxnum].hook != NULL)
return (EADDRINUSE);
/*
* Put our hooks into it (pun not intended)
*/
sc->channel[ctxnum].flags |= CHAN_ACTIVE;
NG_HOOK_SET_PRIVATE(hook, sc->channel + ctxnum);
sc->channel[ctxnum].hook = hook;
sc->datahooks++;
return (0);
}
/*
* Count up the size of the address header if we don't already know
*/
int
ngfrm_addrlen(char *hdr)
{
if (hdr[0] & BYTEX_EA)
return 0;
if (hdr[1] & BYTEX_EA)
return 2;
if (hdr[2] & BYTEX_EA)
return 3;
if (hdr[3] & BYTEX_EA)
return 4;
return 0;
}
/*
* Receive data packet
*/
static int
ngfrm_rcvdata(hook_p hook, item_p item)
{
struct ctxinfo *const ctxp = NG_HOOK_PRIVATE(hook);
int error = 0;
int dlci;
sc_p sc;
int alen;
char *data;
struct mbuf *m;
/* Data doesn't come in from just anywhere (e.g debug hook) */
if (ctxp == NULL) {
error = ENETDOWN;
goto bad;
}
/* If coming from downstream, decode it to a channel */
dlci = ctxp->dlci;
if (dlci == -1)
return (ngfrm_decode(NG_HOOK_NODE(hook), item));
NGI_GET_M(item, m);
/* Derive the softc we will need */
sc = NG_NODE_PRIVATE(NG_HOOK_NODE(hook));
/* If there is no live channel, throw it away */
if ((sc->downstream.hook == NULL)
|| ((ctxp->flags & CHAN_ACTIVE) == 0)) {
error = ENETDOWN;
goto bad;
}
/* Store the DLCI on the front of the packet */
alen = sc->addrlen;
if (alen == 0)
alen = 2; /* default value for transmit */
M_PREPEND(m, alen, M_DONTWAIT);
if (m == NULL) {
error = ENOBUFS;
goto bad;
}
data = mtod(m, char *);
/*
* Shift the lowest bits into the address field untill we are done.
* First byte is MSBits of addr so work backwards.
*/
switch (alen) {
case 2:
data[0] = data[1] = '\0';
SHIFTOUT(makeup + 1, data[1], dlci);
SHIFTOUT(makeup + 0, data[0], dlci);
data[1] |= BYTEX_EA;
break;
case 3:
data[0] = data[1] = data[2] = '\0';
SHIFTOUT(makeup + 3, data[2], dlci); /* 3 and 2 is correct */
SHIFTOUT(makeup + 1, data[1], dlci);
SHIFTOUT(makeup + 0, data[0], dlci);
data[2] |= BYTEX_EA;
break;
case 4:
data[0] = data[1] = data[2] = data[3] = '\0';
SHIFTOUT(makeup + 3, data[3], dlci);
SHIFTOUT(makeup + 2, data[2], dlci);
SHIFTOUT(makeup + 1, data[1], dlci);
SHIFTOUT(makeup + 0, data[0], dlci);
data[3] |= BYTEX_EA;
break;
default:
panic(__func__);
}
/* Send it */
NG_FWD_NEW_DATA(error, item, sc->downstream.hook, m);
return (error);
bad:
NG_FREE_ITEM(item);
NG_FREE_M(m);
return (error);
}
/*
* Decode an incoming frame coming from the switch
*/
static int
ngfrm_decode(node_p node, item_p item)
{
const sc_p sc = NG_NODE_PRIVATE(node);
char *data;
int alen;
u_int dlci = 0;
int error = 0;
int ctxnum;
struct mbuf *m;
NGI_GET_M(item, m);
if (m->m_len < 4 && (m = m_pullup(m, 4)) == NULL) {
error = ENOBUFS;
goto out;
}
data = mtod(m, char *);
if ((alen = sc->addrlen) == 0) {
sc->addrlen = alen = ngfrm_addrlen(data);
}
switch (alen) {
case 2:
SHIFTIN(makeup + 0, data[0], dlci);
SHIFTIN(makeup + 1, data[1], dlci);
break;
case 3:
SHIFTIN(makeup + 0, data[0], dlci);
SHIFTIN(makeup + 1, data[1], dlci);
SHIFTIN(makeup + 3, data[2], dlci); /* 3 and 2 is correct */
break;
case 4:
SHIFTIN(makeup + 0, data[0], dlci);
SHIFTIN(makeup + 1, data[1], dlci);
SHIFTIN(makeup + 2, data[2], dlci);
SHIFTIN(makeup + 3, data[3], dlci);
break;
default:
error = EINVAL;
goto out;
}
if (dlci > 1023) {
error = EINVAL;
goto out;
}
ctxnum = sc->ALT[dlci];
if ((ctxnum & CTX_VALID) && sc->channel[ctxnum &= CTX_VALUE].hook) {
/* Send it */
m_adj(m, alen);
NG_FWD_NEW_DATA(error, item, sc->channel[ctxnum].hook, m);
return (error);
} else {
error = ENETDOWN;
}
out:
NG_FREE_ITEM(item);
NG_FREE_M(m);
return (error);
}
/*
* Shutdown node
*/
static int
ngfrm_shutdown(node_p node)
{
const sc_p sc = NG_NODE_PRIVATE(node);
NG_NODE_SET_PRIVATE(node, NULL);
FREE(sc, M_NETGRAPH);
NG_NODE_UNREF(node);
return (0);
}
/*
* Hook disconnection
*
* Invalidate the private data associated with this dlci.
* For this type, removal of the last link resets tries to destroy the node.
*/
static int
ngfrm_disconnect(hook_p hook)
{
const sc_p sc = NG_NODE_PRIVATE(NG_HOOK_NODE(hook));
struct ctxinfo *const cp = NG_HOOK_PRIVATE(hook);
int dlci;
/* If it's a regular dlci hook, then free resources etc.. */
if (cp != NULL) {
cp->hook = NULL;
dlci = cp->dlci;
if (dlci != -1)
sc->ALT[dlci] = 0;
cp->flags = 0;
sc->datahooks--;
}
if ((NG_NODE_NUMHOOKS(NG_HOOK_NODE(hook)) == 0)
&& (NG_NODE_IS_VALID(NG_HOOK_NODE(hook))))
ng_rmnode_self(NG_HOOK_NODE(hook));
return (0);
}