Whistle's Netgraph link-layer (sometimes more) networking infrastructure.

Been in production for 3 years now. Gives Instant Frame relay to if_sr
and if_ar drivers, and PPPOE support soon. See:
ftp://ftp.whistle.com/pub/archie/netgraph/index.html
for on-line manual pages.

Reviewed by: Doug Rabson (dfr@freebsd.org)
Obtained from:  Whistle CVS tree

1 files changed, 526 insertions, 0 deletions

diff --git a/sys/netgraph/ng_frame_relay.c b/sys/netgraph/ng_frame_relay.c
new file mode 100644
index 0000000..995b769
--- /dev/null
+++ b/sys/netgraph/ng_frame_relay.c
@@ -0,0 +1,526 @@
+
+/*
+ * 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 Elisher <julian@whistle.com>
+ *
+ * $FreeBSD$
+ * $Whistle: ng_frame_relay.c,v 1.16 1999/01/28 23:54:53 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/conf.h>
+#include <sys/errno.h>
+#include <sys/malloc.h>
+#include <sys/mbuf.h>
+#include <sys/socket.h>
+#include <sys/syslog.h>
+#include <machine/clock.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? */
+	char    nodename[NG_NODELEN + 1];	/* store our node name */
+	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 */
+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 int ngfrm_constructor(node_p *nodep);
+static int ngfrm_rmnode(node_p node);
+static int ngfrm_newhook(node_p node, hook_p hook, const char *name);
+static int ngfrm_rcvdata(hook_p hook, struct mbuf *m, meta_p meta);
+static int ngfrm_disconnect(hook_p hook);
+
+/* Other internal functions */
+static int ngfrm_decode(node_p node, struct mbuf * m, meta_p meta);
+static int ngfrm_addrlen(char *hdr);
+static int ngfrm_allocate_CTX(sc_p sc, int dlci);
+
+/* Netgraph type */
+static struct ng_type typestruct = {
+	NG_VERSION,
+	NG_FRAMERELAY_NODE_TYPE,
+	NULL,
+	ngfrm_constructor,
+	NULL,
+	ngfrm_rmnode,
+	ngfrm_newhook,
+	NULL,
+	NULL,
+	ngfrm_rcvdata,
+	ngfrm_rcvdata,
+	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 *nodep)
+{
+	sc_p sc;
+	int error = 0;
+
+	MALLOC(sc, sc_p, sizeof(*sc), M_NETGRAPH, M_NOWAIT);
+	if (!sc)
+		return (ENOMEM);
+	bzero(sc, sizeof(*sc));
+	if ((error = ng_make_node_common(&typestruct, nodep))) {
+		FREE(sc, M_NETGRAPH);
+		return (error);
+	}
+	sc->addrlen = 2;	/* default */
+
+	/* Link the node and our private info */
+	(*nodep)->private = sc;
+	sc->node = *nodep;
+	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 = node->private;
+	const char *cp;
+	char	    c = '\0';
+	int	    digits = 0;
+	int	    dlci = 0;
+	int	    ctxnum;
+
+	/* Check if it's our friend the control hook */
+	if (strcmp(name, NG_FRAMERELAY_HOOK_DEBUG) == 0) {
+		hook->private = 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 */
+		hook->private = &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);
+	while ((digits < 5) && ((c = *cp++) >= '0') && (c <= '9')) {
+		dlci *= 10;
+		dlci += c - '0';
+		digits++;
+	}
+	if ((c != 0) || (digits == 5) || (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;
+	hook->private = 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, struct mbuf *m, meta_p meta)
+{
+	struct	ctxinfo *const ctxp = hook->private;
+	int     error = 0;
+	int     dlci;
+	sc_p    sc;
+	int     alen;
+	char   *data;
+
+	/* 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(hook->node, m, meta));
+
+	/* Derive the softc we will need */
+	sc = hook->node->private;
+
+	/* 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(__FUNCTION__);
+	}
+
+	/* Send it */
+	NG_SEND_DATA(error, sc->downstream.hook, m, meta);
+	return (error);
+
+bad:
+	NG_FREE_DATA(m, meta);
+	return (error);
+}
+
+/*
+ * Decode an incoming frame coming from the switch
+ */
+static int
+ngfrm_decode(node_p node, struct mbuf *m, meta_p meta)
+{
+	const sc_p  sc = node->private;
+	char       *data;
+	int         alen;
+	u_int	    dlci = 0;
+	int	    error = 0;
+	int	    ctxnum;
+
+	if ((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_SEND_DATA(error, sc->channel[ctxnum].hook, m, meta);
+		return (error);
+	} else {
+		error = ENETDOWN;
+	}
+out:
+	NG_FREE_DATA(m, meta);
+	return (error);
+}
+
+/*
+ * Shutdown node
+ */
+static int
+ngfrm_rmnode(node_p node)
+{
+	const sc_p sc = node->private;
+
+	node->flags |= NG_INVALID;
+	ng_cutlinks(node);
+	ng_unname(node);
+	node->private = NULL;
+	FREE(sc, M_NETGRAPH);
+	ng_unref(sc->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 = hook->node->private;
+	struct ctxinfo *const cp = hook->private;
+	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 (hook->node->numhooks == 0)
+		ng_rmnode(hook->node);
+	return (0);
+}