Subversion Repositories or1k_soc_on_altera_embedded_dev_kit

/*

 * llc_input.c - Minimal input path for LLC

 *

 * Copyright (c) 1997 by Procom Technology, Inc.

 *               2001-2003 by Arnaldo Carvalho de Melo <acme@conectiva.com.br>

 *

 * This program can be redistributed or modified under the terms of the

 * GNU General Public License as published by the Free Software Foundation.

 * This program is distributed without any warranty or implied warranty

 * of merchantability or fitness for a particular purpose.

 *

 * See the GNU General Public License for more details.

 */

#include <linux/netdevice.h>

#include <net/net_namespace.h>

#include <net/llc.h>

#include <net/llc_pdu.h>

#include <net/llc_sap.h>

#if 0

#define dprintk(args...) printk(KERN_DEBUG args)

#else

#define dprintk(args...)

#endif

/*

 * Packet handler for the station, registerable because in the minimal

 * LLC core that is taking shape only the very minimal subset of LLC that

 * is needed for things like IPX, Appletalk, etc will stay, with all the

 * rest in the llc1 and llc2 modules.

 */

static void (*llc_station_handler)(struct sk_buff *skb);

/*

 * Packet handlers for LLC_DEST_SAP and LLC_DEST_CONN.

 */

static void (*llc_type_handlers[2])(struct llc_sap *sap,

                                    struct sk_buff *skb);

void llc_add_pack(int type, void (*handler)(struct llc_sap *sap,

                                            struct sk_buff *skb))

{

        if (type == LLC_DEST_SAP || type == LLC_DEST_CONN)

                llc_type_handlers[type - 1] = handler;

}

void llc_remove_pack(int type)

{

        if (type == LLC_DEST_SAP || type == LLC_DEST_CONN)

                llc_type_handlers[type - 1] = NULL;

}

void llc_set_station_handler(void (*handler)(struct sk_buff *skb))

{

        llc_station_handler = handler;

}

/**

 *      llc_pdu_type - returns which LLC component must handle for PDU

 *      @skb: input skb

 *

 *      This function returns which LLC component must handle this PDU.

 */

static __inline__ int llc_pdu_type(struct sk_buff *skb)

{

        int type = LLC_DEST_CONN; /* I-PDU or S-PDU type */

        struct llc_pdu_sn *pdu = llc_pdu_sn_hdr(skb);

        if ((pdu->ctrl_1 & LLC_PDU_TYPE_MASK) != LLC_PDU_TYPE_U)

                goto out;

        switch (LLC_U_PDU_CMD(pdu)) {

        case LLC_1_PDU_CMD_XID:

        case LLC_1_PDU_CMD_UI:

        case LLC_1_PDU_CMD_TEST:

                type = LLC_DEST_SAP;

                break;

        case LLC_2_PDU_CMD_SABME:

        case LLC_2_PDU_CMD_DISC:

        case LLC_2_PDU_RSP_UA:

        case LLC_2_PDU_RSP_DM:

        case LLC_2_PDU_RSP_FRMR:

                break;

        default:

                type = LLC_DEST_INVALID;

                break;

        }

out:

        return type;

}

/**

 *      llc_fixup_skb - initializes skb pointers

 *      @skb: This argument points to incoming skb

 *

 *      Initializes internal skb pointer to start of network layer by deriving

 *      length of LLC header; finds length of LLC control field in LLC header

 *      by looking at the two lowest-order bits of the first control field

 *      byte; field is either 3 or 4 bytes long.

 */

static inline int llc_fixup_skb(struct sk_buff *skb)

{

        u8 llc_len = 2;

        struct llc_pdu_un *pdu;

        if (unlikely(!pskb_may_pull(skb, sizeof(*pdu))))

                return 0;

        pdu = (struct llc_pdu_un *)skb->data;

        if ((pdu->ctrl_1 & LLC_PDU_TYPE_MASK) == LLC_PDU_TYPE_U)

                llc_len = 1;

        llc_len += 2;

        if (unlikely(!pskb_may_pull(skb, llc_len)))

                return 0;

        skb->transport_header += llc_len;

        skb_pull(skb, llc_len);

        if (skb->protocol == htons(ETH_P_802_2)) {

                __be16 pdulen = eth_hdr(skb)->h_proto;

                u16 data_size = ntohs(pdulen) - llc_len;

                if (unlikely(pskb_trim_rcsum(skb, data_size)))

                        return 0;

        }

        return 1;

}

/**

 *      llc_rcv - 802.2 entry point from net lower layers

 *      @skb: received pdu

 *      @dev: device that receive pdu

 *      @pt: packet type

 *

 *      When the system receives a 802.2 frame this function is called. It

 *      checks SAP and connection of received pdu and passes frame to

 *      llc_{station,sap,conn}_rcv for sending to proper state machine. If

 *      the frame is related to a busy connection (a connection is sending

 *      data now), it queues this frame in the connection's backlog.

 */

int llc_rcv(struct sk_buff *skb, struct net_device *dev,

            struct packet_type *pt, struct net_device *orig_dev)

{

        struct llc_sap *sap;

        struct llc_pdu_sn *pdu;

        int dest;

        int (*rcv)(struct sk_buff *, struct net_device *,

                   struct packet_type *, struct net_device *);

        if (dev->nd_net != &init_net)

                goto drop;

        /*

         * When the interface is in promisc. mode, drop all the crap that it

         * receives, do not try to analyse it.

         */

        if (unlikely(skb->pkt_type == PACKET_OTHERHOST)) {

                dprintk("%s: PACKET_OTHERHOST\n", __FUNCTION__);

                goto drop;

        }

        skb = skb_share_check(skb, GFP_ATOMIC);

        if (unlikely(!skb))

                goto out;

        if (unlikely(!llc_fixup_skb(skb)))

                goto drop;

        pdu = llc_pdu_sn_hdr(skb);

        if (unlikely(!pdu->dsap)) /* NULL DSAP, refer to station */

               goto handle_station;

        sap = llc_sap_find(pdu->dsap);

        if (unlikely(!sap)) {/* unknown SAP */

                dprintk("%s: llc_sap_find(%02X) failed!\n", __FUNCTION__,

                        pdu->dsap);

                goto drop;

        }

        /*

         * First the upper layer protocols that don't need the full

         * LLC functionality

         */

        rcv = rcu_dereference(sap->rcv_func);

        if (rcv) {

                struct sk_buff *cskb = skb_clone(skb, GFP_ATOMIC);

                if (cskb)

                        rcv(cskb, dev, pt, orig_dev);

        }

        dest = llc_pdu_type(skb);

        if (unlikely(!dest || !llc_type_handlers[dest - 1]))

                goto drop_put;

        llc_type_handlers[dest - 1](sap, skb);

out_put:

        llc_sap_put(sap);

out:

        return 0;

drop:

        kfree_skb(skb);

        goto out;

drop_put:

        kfree_skb(skb);

        goto out_put;

handle_station:

        if (!llc_station_handler)

                goto drop;

        llc_station_handler(skb);

        goto out;

}

EXPORT_SYMBOL(llc_add_pack);

EXPORT_SYMBOL(llc_remove_pack);

EXPORT_SYMBOL(llc_set_station_handler);