526 lines
13 KiB
C
526 lines
13 KiB
C
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/*
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* ng_frame_relay.c
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*
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* Copyright (c) 1996-1999 Whistle Communications, Inc.
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* All rights reserved.
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*
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* Subject to the following obligations and disclaimer of warranty, use and
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* redistribution of this software, in source or object code forms, with or
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* without modifications are expressly permitted by Whistle Communications;
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* provided, however, that:
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* 1. Any and all reproductions of the source or object code must include the
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* copyright notice above and the following disclaimer of warranties; and
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* 2. No rights are granted, in any manner or form, to use Whistle
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* Communications, Inc. trademarks, including the mark "WHISTLE
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* COMMUNICATIONS" on advertising, endorsements, or otherwise except as
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* such appears in the above copyright notice or in the software.
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*
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* THIS SOFTWARE IS BEING PROVIDED BY WHISTLE COMMUNICATIONS "AS IS", AND
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* TO THE MAXIMUM EXTENT PERMITTED BY LAW, WHISTLE COMMUNICATIONS MAKES NO
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* REPRESENTATIONS OR WARRANTIES, EXPRESS OR IMPLIED, REGARDING THIS SOFTWARE,
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* INCLUDING WITHOUT LIMITATION, ANY AND ALL IMPLIED WARRANTIES OF
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* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, OR NON-INFRINGEMENT.
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* WHISTLE COMMUNICATIONS DOES NOT WARRANT, GUARANTEE, OR MAKE ANY
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* REPRESENTATIONS REGARDING THE USE OF, OR THE RESULTS OF THE USE OF THIS
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* SOFTWARE IN TERMS OF ITS CORRECTNESS, ACCURACY, RELIABILITY OR OTHERWISE.
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* IN NO EVENT SHALL WHISTLE COMMUNICATIONS BE LIABLE FOR ANY DAMAGES
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* RESULTING FROM OR ARISING OUT OF ANY USE OF THIS SOFTWARE, INCLUDING
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* WITHOUT LIMITATION, ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY,
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* PUNITIVE, OR CONSEQUENTIAL DAMAGES, PROCUREMENT OF SUBSTITUTE GOODS OR
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* SERVICES, LOSS OF USE, DATA OR PROFITS, HOWEVER CAUSED AND UNDER ANY
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* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
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* THIS SOFTWARE, EVEN IF WHISTLE COMMUNICATIONS IS ADVISED OF THE POSSIBILITY
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* OF SUCH DAMAGE.
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*
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* Author: Julian Elisher <julian@whistle.com>
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*
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* $FreeBSD$
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* $Whistle: ng_frame_relay.c,v 1.20 1999/11/01 09:24:51 julian Exp $
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*/
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/*
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* This node implements the frame relay protocol, not including
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* the LMI line management. This means basically keeping track
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* of which DLCI's are active, doing frame (de)multiplexing, etc.
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*
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* It has a 'downstream' hook that goes to the line, and a
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* hook for each DLCI (eg, 'dlci16').
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*/
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#include <sys/param.h>
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#include <sys/systm.h>
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#include <sys/kernel.h>
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#include <sys/conf.h>
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#include <sys/errno.h>
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#include <sys/malloc.h>
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#include <sys/mbuf.h>
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#include <sys/socket.h>
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#include <sys/syslog.h>
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#include <machine/clock.h>
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#include <netgraph/ng_message.h>
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#include <netgraph/netgraph.h>
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#include <netgraph/ng_frame_relay.h>
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/*
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* Line info, and status per channel.
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*/
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struct ctxinfo { /* one per active hook */
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u_int flags;
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#define CHAN_VALID 0x01 /* assigned to a channel */
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#define CHAN_ACTIVE 0x02 /* bottom level active */
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int dlci; /* the dlci assigned to this context */
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hook_p hook; /* if there's a hook assigned.. */
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};
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#define MAX_CT 16 /* # of dlci's active at a time (POWER OF 2!) */
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struct frmrel_softc {
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int unit; /* which card are we? */
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int datahooks; /* number of data hooks attached */
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node_p node; /* netgraph node */
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int addrlen; /* address header length */
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int flags; /* state */
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int mtu; /* guess */
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u_char remote_seq; /* sequence number the remote sent */
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u_char local_seq; /* sequence number the remote rcvd */
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u_short ALT[1024]; /* map DLCIs to CTX */
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#define CTX_VALID 0x8000 /* this bit means it's a valid CTX */
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#define CTX_VALUE (MAX_CT - 1) /* mask for context part */
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struct ctxinfo channel[MAX_CT];
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struct ctxinfo downstream;
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};
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typedef struct frmrel_softc *sc_p;
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#define BYTEX_EA 0x01 /* End Address. Always 0 on byte1 */
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#define BYTE1_C_R 0x02
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#define BYTE2_FECN 0x08 /* forwards congestion notification */
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#define BYTE2_BECN 0x04 /* Backward congestion notification */
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#define BYTE2_DE 0x02 /* Discard elligability */
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#define LASTBYTE_D_C 0x02 /* last byte is dl_core or dlci info */
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/* Used to do headers */
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static struct segment {
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u_char mask;
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u_char shift;
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u_char width;
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} makeup[] = {
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{ 0xfc, 2, 6 },
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{ 0xf0, 4, 4 },
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{ 0xfe, 1, 7 },
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{ 0xfc, 2, 6 }
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};
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#define SHIFTIN(segment, byte, dlci) \
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{ \
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(dlci) <<= (segment)->width; \
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(dlci) |= \
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(((byte) & (segment)->mask) >> (segment)->shift); \
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}
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#define SHIFTOUT(segment, byte, dlci) \
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{ \
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(byte) |= (((dlci) << (segment)->shift) & (segment)->mask); \
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(dlci) >>= (segment)->width; \
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}
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/* Netgraph methods */
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static ng_constructor_t ngfrm_constructor;
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static ng_shutdown_t ngfrm_rmnode;
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static ng_newhook_t ngfrm_newhook;
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static ng_rcvdata_t ngfrm_rcvdata;
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static ng_disconnect_t ngfrm_disconnect;
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/* Other internal functions */
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static int ngfrm_decode(node_p node, struct mbuf * m, meta_p meta);
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static int ngfrm_addrlen(char *hdr);
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static int ngfrm_allocate_CTX(sc_p sc, int dlci);
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/* Netgraph type */
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static struct ng_type typestruct = {
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NG_VERSION,
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NG_FRAMERELAY_NODE_TYPE,
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NULL,
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ngfrm_constructor,
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NULL,
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ngfrm_rmnode,
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ngfrm_newhook,
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NULL,
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NULL,
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ngfrm_rcvdata,
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ngfrm_rcvdata,
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ngfrm_disconnect
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};
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NETGRAPH_INIT(framerelay, &typestruct);
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/*
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* Given a DLCI, return the index of the context table entry for it,
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* Allocating a new one if needs be, or -1 if none available.
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*/
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static int
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ngfrm_allocate_CTX(sc_p sc, int dlci)
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{
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u_int ctxnum = -1; /* what ctx number we are using */
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volatile struct ctxinfo *CTXp = NULL;
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/* Sanity check the dlci value */
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if (dlci > 1023)
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return (-1);
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/* Check to see if we already have an entry for this DLCI */
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if (sc->ALT[dlci]) {
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if ((ctxnum = sc->ALT[dlci] & CTX_VALUE) < MAX_CT) {
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CTXp = sc->channel + ctxnum;
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} else {
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ctxnum = -1;
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sc->ALT[dlci] = 0; /* paranoid but... */
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}
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}
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/*
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* If the index has no valid entry yet, then we need to allocate a
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* CTX number to it
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*/
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if (CTXp == NULL) {
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for (ctxnum = 0; ctxnum < MAX_CT; ctxnum++) {
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/*
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* If the VALID flag is empty it is unused
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*/
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if ((sc->channel[ctxnum].flags & CHAN_VALID) == 0) {
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bzero(sc->channel + ctxnum,
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sizeof(struct ctxinfo));
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CTXp = sc->channel + ctxnum;
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sc->ALT[dlci] = ctxnum | CTX_VALID;
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sc->channel[ctxnum].dlci = dlci;
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sc->channel[ctxnum].flags = CHAN_VALID;
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break;
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}
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}
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}
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/*
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* If we still don't have a CTX pointer, then we never found a free
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* spot so give up now..
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*/
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if (!CTXp) {
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log(LOG_ERR, "No CTX available for dlci %d\n", dlci);
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return (-1);
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}
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return (ctxnum);
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}
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/*
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* Node constructor
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*/
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static int
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ngfrm_constructor(node_p *nodep)
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{
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sc_p sc;
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int error = 0;
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MALLOC(sc, sc_p, sizeof(*sc), M_NETGRAPH, M_NOWAIT);
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if (!sc)
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return (ENOMEM);
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bzero(sc, sizeof(*sc));
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if ((error = ng_make_node_common(&typestruct, nodep))) {
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FREE(sc, M_NETGRAPH);
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return (error);
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}
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sc->addrlen = 2; /* default */
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/* Link the node and our private info */
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(*nodep)->private = sc;
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sc->node = *nodep;
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return (0);
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}
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/*
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* Add a new hook
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*
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* We allow hooks called "debug", "downstream" and dlci[0-1023]
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* The hook's private info points to our stash of info about that
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* channel. A NULL pointer is debug and a DLCI of -1 means downstream.
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*/
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static int
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ngfrm_newhook(node_p node, hook_p hook, const char *name)
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{
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const sc_p sc = node->private;
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const char *cp;
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char c = '\0';
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int digits = 0;
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int dlci = 0;
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int ctxnum;
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/* Check if it's our friend the control hook */
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if (strcmp(name, NG_FRAMERELAY_HOOK_DEBUG) == 0) {
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hook->private = NULL; /* paranoid */
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return (0);
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}
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/*
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* All other hooks either start with 'dlci' and have a decimal
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* trailing channel number up to 4 digits, or are the downstream
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* hook.
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*/
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if (strncmp(name, NG_FRAMERELAY_HOOK_DLCI,
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strlen(NG_FRAMERELAY_HOOK_DLCI)) != 0) {
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/* It must be the downstream connection */
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if (strcmp(name, NG_FRAMERELAY_HOOK_DOWNSTREAM) != 0)
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return EINVAL;
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/* Make sure we haven't already got one (paranoid) */
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if (sc->downstream.hook)
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return (EADDRINUSE);
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/* OK add it */
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hook->private = &sc->downstream;
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sc->downstream.hook = hook;
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sc->downstream.dlci = -1;
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sc->downstream.flags |= CHAN_ACTIVE;
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sc->datahooks++;
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return (0);
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}
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/* Must be a dlci hook at this point */
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cp = name + strlen(NG_FRAMERELAY_HOOK_DLCI);
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while ((digits < 5) && ((c = *cp++) >= '0') && (c <= '9')) {
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dlci *= 10;
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dlci += c - '0';
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digits++;
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}
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if ((c != 0) || (digits == 5) || (dlci < 0) || (dlci > 1023))
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return (EINVAL);
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/*
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* We have a dlci, now either find it, or allocate it. It's possible
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* that we might have seen packets for it already and made an entry
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* for it.
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*/
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ctxnum = ngfrm_allocate_CTX(sc, dlci);
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if (ctxnum == -1)
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return (ENOBUFS);
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/*
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* Be paranoid: if it's got a hook already, that dlci is in use .
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* Generic code can not catch all the synonyms (e.g. dlci016 vs
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* dlci16)
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*/
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if (sc->channel[ctxnum].hook != NULL)
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return (EADDRINUSE);
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/*
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* Put our hooks into it (pun not intended)
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*/
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sc->channel[ctxnum].flags |= CHAN_ACTIVE;
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hook->private = sc->channel + ctxnum;
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sc->channel[ctxnum].hook = hook;
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sc->datahooks++;
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return (0);
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}
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/*
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* Count up the size of the address header if we don't already know
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*/
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int
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ngfrm_addrlen(char *hdr)
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{
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if (hdr[0] & BYTEX_EA)
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return 0;
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if (hdr[1] & BYTEX_EA)
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return 2;
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if (hdr[2] & BYTEX_EA)
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return 3;
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if (hdr[3] & BYTEX_EA)
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return 4;
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return 0;
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}
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/*
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* Receive data packet
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*/
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static int
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ngfrm_rcvdata(hook_p hook, struct mbuf *m, meta_p meta)
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{
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struct ctxinfo *const ctxp = hook->private;
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int error = 0;
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int dlci;
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sc_p sc;
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int alen;
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char *data;
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/* Data doesn't come in from just anywhere (e.g debug hook) */
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if (ctxp == NULL) {
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error = ENETDOWN;
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goto bad;
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}
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/* If coming from downstream, decode it to a channel */
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dlci = ctxp->dlci;
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if (dlci == -1)
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return (ngfrm_decode(hook->node, m, meta));
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/* Derive the softc we will need */
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sc = hook->node->private;
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/* If there is no live channel, throw it away */
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if ((sc->downstream.hook == NULL)
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|| ((ctxp->flags & CHAN_ACTIVE) == 0)) {
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error = ENETDOWN;
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goto bad;
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}
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/* Store the DLCI on the front of the packet */
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alen = sc->addrlen;
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if (alen == 0)
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alen = 2; /* default value for transmit */
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M_PREPEND(m, alen, M_DONTWAIT);
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if (m == NULL) {
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error = ENOBUFS;
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goto bad;
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}
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data = mtod(m, char *);
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/*
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* Shift the lowest bits into the address field untill we are done.
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* First byte is MSBits of addr so work backwards.
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*/
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switch (alen) {
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case 2:
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data[0] = data[1] = '\0';
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SHIFTOUT(makeup + 1, data[1], dlci);
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SHIFTOUT(makeup + 0, data[0], dlci);
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data[1] |= BYTEX_EA;
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break;
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case 3:
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data[0] = data[1] = data[2] = '\0';
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SHIFTOUT(makeup + 3, data[2], dlci); /* 3 and 2 is correct */
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SHIFTOUT(makeup + 1, data[1], dlci);
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SHIFTOUT(makeup + 0, data[0], dlci);
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data[2] |= BYTEX_EA;
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break;
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case 4:
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data[0] = data[1] = data[2] = data[3] = '\0';
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SHIFTOUT(makeup + 3, data[3], dlci);
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SHIFTOUT(makeup + 2, data[2], dlci);
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SHIFTOUT(makeup + 1, data[1], dlci);
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SHIFTOUT(makeup + 0, data[0], dlci);
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data[3] |= BYTEX_EA;
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break;
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default:
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panic(__FUNCTION__);
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}
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/* Send it */
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NG_SEND_DATA(error, sc->downstream.hook, m, meta);
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return (error);
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bad:
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NG_FREE_DATA(m, meta);
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return (error);
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}
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/*
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* Decode an incoming frame coming from the switch
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*/
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static int
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ngfrm_decode(node_p node, struct mbuf *m, meta_p meta)
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{
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const sc_p sc = node->private;
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char *data;
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int alen;
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u_int dlci = 0;
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int error = 0;
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int ctxnum;
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if (m->m_len < 4 && (m = m_pullup(m, 4)) == NULL) {
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error = ENOBUFS;
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goto out;
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}
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data = mtod(m, char *);
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if ((alen = sc->addrlen) == 0) {
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sc->addrlen = alen = ngfrm_addrlen(data);
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}
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switch (alen) {
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case 2:
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SHIFTIN(makeup + 0, data[0], dlci);
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SHIFTIN(makeup + 1, data[1], dlci);
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break;
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case 3:
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SHIFTIN(makeup + 0, data[0], dlci);
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SHIFTIN(makeup + 1, data[1], dlci);
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SHIFTIN(makeup + 3, data[2], dlci); /* 3 and 2 is correct */
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break;
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case 4:
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SHIFTIN(makeup + 0, data[0], dlci);
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SHIFTIN(makeup + 1, data[1], dlci);
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SHIFTIN(makeup + 2, data[2], dlci);
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SHIFTIN(makeup + 3, data[3], dlci);
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break;
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default:
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error = EINVAL;
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goto out;
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}
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if (dlci > 1023) {
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error = EINVAL;
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goto out;
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}
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ctxnum = sc->ALT[dlci];
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if ((ctxnum & CTX_VALID) && sc->channel[ctxnum &= CTX_VALUE].hook) {
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/* Send it */
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m_adj(m, alen);
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NG_SEND_DATA(error, sc->channel[ctxnum].hook, m, meta);
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return (error);
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} else {
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error = ENETDOWN;
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}
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out:
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NG_FREE_DATA(m, meta);
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return (error);
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}
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/*
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* Shutdown node
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*/
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static int
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ngfrm_rmnode(node_p node)
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{
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const sc_p sc = node->private;
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node->flags |= NG_INVALID;
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ng_cutlinks(node);
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ng_unname(node);
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node->private = NULL;
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FREE(sc, M_NETGRAPH);
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ng_unref(sc->node);
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return (0);
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}
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/*
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* Hook disconnection
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*
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* Invalidate the private data associated with this dlci.
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* For this type, removal of the last link resets tries to destroy the node.
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*/
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static int
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ngfrm_disconnect(hook_p hook)
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{
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const sc_p sc = hook->node->private;
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struct ctxinfo *const cp = hook->private;
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int dlci;
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/* If it's a regular dlci hook, then free resources etc.. */
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if (cp != NULL) {
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cp->hook = NULL;
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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);
|
|
}
|