// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * dvb_net.c
 *
 * Copyright (C) 2001 Convergence integrated media GmbH
 *                    Ralph Metzler <ralph@convergence.de>
 * Copyright (C) 2002 Ralph Metzler <rjkm@metzlerbros.de>
 *
 * ULE Decapsulation code:
 * Copyright (C) 2003, 2004 gcs - Global Communication & Services GmbH.
 *                      and Department of Scientific Computing
 *                          Paris Lodron University of Salzburg.
 *                          Hilmar Linder <hlinder@cosy.sbg.ac.at>
 *                      and Wolfram Stering <wstering@cosy.sbg.ac.at>
 *
 * ULE Decaps according to RFC 4326.
 */

/*
 * ULE ChangeLog:
 * Feb 2004: hl/ws v1: Implementing draft-fair-ipdvb-ule-01.txt
 *
 * Dec 2004: hl/ws v2: Implementing draft-ietf-ipdvb-ule-03.txt:
 *                       ULE Extension header handling.
 *                     Bugreports by Moritz Vieth and Hanno Tersteegen,
 *                       Fraunhofer Institute for Open Communication Systems
 *                       Competence Center for Advanced Satellite Communications.
 *                     Bugfixes and robustness improvements.
 *                     Filtering on dest MAC addresses, if present (D-Bit = 0)
 *                     DVB_ULE_DEBUG compile-time option.
 * Apr 2006: cp v3:    Bugfixes and compliency with RFC 4326 (ULE) by
 *                       Christian Praehauser <cpraehaus@cosy.sbg.ac.at>,
 *                       Paris Lodron University of Salzburg.
 */

/*
 * FIXME / TODO (dvb_net.c):
 *
 * Unloading does not work for 2.6.9 kernels: a refcount doesn't go to zero.
 *
 */

#define pr_fmt(fmt) "dvb_net: " fmt

#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/netdevice.h>
#include <linux/nospec.h>
#include <linux/etherdevice.h>
#include <linux/dvb/net.h>
#include <linux/uio.h>
#include <linux/uaccess.h>
#include <linux/crc32.h>
#include <linux/mutex.h>
#include <linux/sched.h>

#include <media/dvb_demux.h>
#include <media/dvb_net.h>

static inline __u32 iov_crc32( __u32 c, struct kvec *iov, unsigned int cnt )
{
        unsigned int j;
        for (j = 0; j < cnt; j++)
                c = crc32_be( c, iov[j].iov_base, iov[j].iov_len );
        return c;
}


#define DVB_NET_MULTICAST_MAX 10

#ifdef DVB_ULE_DEBUG
/*
 * The code inside DVB_ULE_DEBUG keeps a history of the
 * last 100 TS cells processed.
 */
static unsigned char ule_hist[100*TS_SZ] = { 0 };
static unsigned char *ule_where = ule_hist, ule_dump;

static void hexdump(const unsigned char *buf, unsigned short len)
{
        print_hex_dump_debug("", DUMP_PREFIX_OFFSET, 16, 1, buf, len, true);
}
#endif

struct dvb_net_priv {
        int in_use;
        u16 pid;
        struct net_device *net;
        struct dvb_net *host;
        struct dmx_demux *demux;
        struct dmx_section_feed *secfeed;
        struct dmx_section_filter *secfilter;
        struct dmx_ts_feed *tsfeed;
        int multi_num;
        struct dmx_section_filter *multi_secfilter[DVB_NET_MULTICAST_MAX];
        unsigned char multi_macs[DVB_NET_MULTICAST_MAX][6];
        int rx_mode;
#define RX_MODE_UNI 0
#define RX_MODE_MULTI 1
#define RX_MODE_ALL_MULTI 2
#define RX_MODE_PROMISC 3
        struct work_struct set_multicast_list_wq;
        struct work_struct restart_net_feed_wq;
        unsigned char feedtype;                 /* Either FEED_TYPE_ or FEED_TYPE_ULE */
        int need_pusi;                          /* Set to 1, if synchronization on PUSI required. */
        unsigned char tscc;                     /* TS continuity counter after sync on PUSI. */
        struct sk_buff *ule_skb;                /* ULE SNDU decodes into this buffer. */
        unsigned char *ule_next_hdr;            /* Pointer into skb to next ULE extension header. */
        unsigned short ule_sndu_len;            /* ULE SNDU length in bytes, w/o D-Bit. */
        unsigned short ule_sndu_type;           /* ULE SNDU type field, complete. */
        unsigned char ule_sndu_type_1;          /* ULE SNDU type field, if split across 2 TS cells. */
        unsigned char ule_dbit;                 /* Whether the DestMAC address present
                                                 * or not (bit is set). */
        unsigned char ule_bridged;              /* Whether the ULE_BRIDGED extension header was found. */
        int ule_sndu_remain;                    /* Nr. of bytes still required for current ULE SNDU. */
        unsigned long ts_count;                 /* Current ts cell counter. */
        struct mutex mutex;
};


/*
 *      Determine the packet's protocol ID. The rule here is that we
 *      assume 802.3 if the type field is short enough to be a length.
 *      This is normal practice and works for any 'now in use' protocol.
 *
 *  stolen from eth.c out of the linux kernel, hacked for dvb-device
 *  by Michael Holzt <kju@debian.org>
 */
static __be16 dvb_net_eth_type_trans(struct sk_buff *skb,
                                      struct net_device *dev)
{
        struct ethhdr *eth;
        unsigned char *rawp;

        skb_reset_mac_header(skb);
        skb_pull(skb,dev->hard_header_len);
        eth = eth_hdr(skb);

        if (*eth->h_dest & 1) {
                if(ether_addr_equal(eth->h_dest,dev->broadcast))
                        skb->pkt_type=PACKET_BROADCAST;
                else
                        skb->pkt_type=PACKET_MULTICAST;
        }

        if (ntohs(eth->h_proto) >= ETH_P_802_3_MIN)
                return eth->h_proto;

        rawp = skb->data;

        /*
         *      This is a magic hack to spot IPX packets. Older Novell breaks
         *      the protocol design and runs IPX over 802.3 without an 802.2 LLC
         *      layer. We look for FFFF which isn't a used 802.2 SSAP/DSAP. This
         *      won't work for fault tolerant netware but does for the rest.
         */
        if (*(unsigned short *)rawp == 0xFFFF)
                return htons(ETH_P_802_3);

        /*
         *      Real 802.2 LLC
         */
        return htons(ETH_P_802_2);
}

#define TS_SZ   188
#define TS_SYNC 0x47
#define TS_TEI  0x80
#define TS_SC   0xC0
#define TS_PUSI 0x40
#define TS_AF_A 0x20
#define TS_AF_D 0x10

/* ULE Extension Header handlers. */

#define ULE_TEST        0
#define ULE_BRIDGED     1

#define ULE_OPTEXTHDR_PADDING 0

static int ule_test_sndu( struct dvb_net_priv *p )
{
        return -1;
}

static int ule_bridged_sndu( struct dvb_net_priv *p )
{
        struct ethhdr *hdr = (struct ethhdr*) p->ule_next_hdr;
        if(ntohs(hdr->h_proto) < ETH_P_802_3_MIN) {
                int framelen = p->ule_sndu_len - ((p->ule_next_hdr+sizeof(struct ethhdr)) - p->ule_skb->data);
                /* A frame Type < ETH_P_802_3_MIN for a bridged frame, introduces a LLC Length field. */
                if(framelen != ntohs(hdr->h_proto)) {
                        return -1;
                }
        }
        /* Note:
         * From RFC4326:
         *  "A bridged SNDU is a Mandatory Extension Header of Type 1.
         *   It must be the final (or only) extension header specified in the header chain of a SNDU."
         * The 'ule_bridged' flag will cause the extension header processing loop to terminate.
         */
        p->ule_bridged = 1;
        return 0;
}

static int ule_exthdr_padding(struct dvb_net_priv *p)
{
        return 0;
}

/*
 * Handle ULE extension headers.
 *  Function is called after a successful CRC32 verification of an ULE SNDU to complete its decoding.
 *  Returns: >= 0: nr. of bytes consumed by next extension header
 *           -1:   Mandatory extension header that is not recognized or TEST SNDU; discard.
 */
static int handle_one_ule_extension( struct dvb_net_priv *p )
{
        /* Table of mandatory extension header handlers.  The header type is the index. */
        static int (*ule_mandatory_ext_handlers[255])( struct dvb_net_priv *p ) =
                { [0] = ule_test_sndu, [1] = ule_bridged_sndu, [2] = NULL,  };

        /* Table of optional extension header handlers.  The header type is the index. */
        static int (*ule_optional_ext_handlers[255])( struct dvb_net_priv *p ) =
                { [0] = ule_exthdr_padding, [1] = NULL, };

        int ext_len = 0;
        unsigned char hlen = (p->ule_sndu_type & 0x0700) >> 8;
        unsigned char htype = p->ule_sndu_type & 0x00FF;

        if (htype >= ARRAY_SIZE(ule_mandatory_ext_handlers))
                return -1;

        /* Discriminate mandatory and optional extension headers. */
        if (hlen == 0) {
                /* Mandatory extension header */
                if (ule_mandatory_ext_handlers[htype]) {
                        ext_len = ule_mandatory_ext_handlers[htype]( p );
                        if(ext_len >= 0) {
                                p->ule_next_hdr += ext_len;
                                if (!p->ule_bridged) {
                                        p->ule_sndu_type = ntohs(*(__be16 *)p->ule_next_hdr);
                                        p->ule_next_hdr += 2;
                                } else {
                                        p->ule_sndu_type = ntohs(*(__be16 *)(p->ule_next_hdr + ((p->ule_dbit ? 2 : 3) * ETH_ALEN)));
                                        /* This assures the extension handling loop will terminate. */
                                }
                        }
                        // else: extension handler failed or SNDU should be discarded
                } else
                        ext_len = -1;   /* SNDU has to be discarded. */
        } else {
                /* Optional extension header.  Calculate the length. */
                ext_len = hlen << 1;
                /* Process the optional extension header according to its type. */
                if (ule_optional_ext_handlers[htype])
                        (void)ule_optional_ext_handlers[htype]( p );
                p->ule_next_hdr += ext_len;
                p->ule_sndu_type = ntohs( *(__be16 *)(p->ule_next_hdr-2) );
                /*
                 * note: the length of the next header type is included in the
                 * length of THIS optional extension header
                 */
        }

        return ext_len;
}

static int handle_ule_extensions( struct dvb_net_priv *p )
{
        int total_ext_len = 0, l;

        p->ule_next_hdr = p->ule_skb->data;
        do {
                l = handle_one_ule_extension( p );
                if (l < 0)
                        return l;       /* Stop extension header processing and discard SNDU. */
                total_ext_len += l;
                pr_debug("ule_next_hdr=%p, ule_sndu_type=%i, l=%i, total_ext_len=%i\n",
                         p->ule_next_hdr, (int)p->ule_sndu_type,
                         l, total_ext_len);

        } while (p->ule_sndu_type < ETH_P_802_3_MIN);

        return total_ext_len;
}


/* Prepare for a new ULE SNDU: reset the decoder state. */
static inline void reset_ule( struct dvb_net_priv *p )
{
        p->ule_skb = NULL;
        p->ule_next_hdr = NULL;
        p->ule_sndu_len = 0;
        p->ule_sndu_type = 0;
        p->ule_sndu_type_1 = 0;
        p->ule_sndu_remain = 0;
        p->ule_dbit = 0xFF;
        p->ule_bridged = 0;
}

/*
 * Decode ULE SNDUs according to draft-ietf-ipdvb-ule-03.txt from a sequence of
 * TS cells of a single PID.
 */

struct dvb_net_ule_handle {
        struct net_device *dev;
        struct dvb_net_priv *priv;
        struct ethhdr *ethh;
        const u8 *buf;
        size_t buf_len;
        unsigned long skipped;
        const u8 *ts, *ts_end, *from_where;
        u8 ts_remain, how_much, new_ts;
        bool error;
};

static int dvb_net_ule_new_ts_cell(struct dvb_net_ule_handle *h)
{
        /* We are about to process a new TS cell. */

#ifdef DVB_ULE_DEBUG
        if (ule_where >= &ule_hist[100*TS_SZ])
                ule_where = ule_hist;
        memcpy(ule_where, h->ts, TS_SZ);
        if (ule_dump) {
                hexdump(ule_where, TS_SZ);
                ule_dump = 0;
        }
        ule_where += TS_SZ;
#endif

        /*
         * Check TS h->error conditions: sync_byte, transport_error_indicator,
         * scrambling_control .
         */
        if ((h->ts[0] != TS_SYNC) || (h->ts[1] & TS_TEI) ||
            ((h->ts[3] & TS_SC) != 0)) {
                pr_warn("%lu: Invalid TS cell: SYNC %#x, TEI %u, SC %#x.\n",
                        h->priv->ts_count, h->ts[0],
                        (h->ts[1] & TS_TEI) >> 7,
                        (h->ts[3] & TS_SC) >> 6);

                /* Drop partly decoded SNDU, reset state, resync on PUSI. */
                if (h->priv->ule_skb) {
                        dev_kfree_skb(h->priv->ule_skb);
                        /* Prepare for next SNDU. */
                        h->dev->stats.rx_errors++;
                        h->dev->stats.rx_frame_errors++;
                }
                reset_ule(h->priv);
                h->priv->need_pusi = 1;

                /* Continue with next TS cell. */
                h->ts += TS_SZ;
                h->priv->ts_count++;
                return 1;
        }

        h->ts_remain = 184;
        h->from_where = h->ts + 4;

        return 0;
}

static int dvb_net_ule_ts_pusi(struct dvb_net_ule_handle *h)
{
        if (h->ts[1] & TS_PUSI) {
                /* Find beginning of first ULE SNDU in current TS cell. */
                /* Synchronize continuity counter. */
                h->priv->tscc = h->ts[3] & 0x0F;
                /* There is a pointer field here. */
                if (h->ts[4] > h->ts_remain) {
                        pr_err("%lu: Invalid ULE packet (pointer field %d)\n",
                                h->priv->ts_count, h->ts[4]);
                        h->ts += TS_SZ;
                        h->priv->ts_count++;
                        return 1;
                }
                /* Skip to destination of pointer field. */
                h->from_where = &h->ts[5] + h->ts[4];
                h->ts_remain -= 1 + h->ts[4];
                h->skipped = 0;
        } else {
                h->skipped++;
                h->ts += TS_SZ;
                h->priv->ts_count++;
                return 1;
        }

        return 0;
}

static int dvb_net_ule_new_ts(struct dvb_net_ule_handle *h)
{
        /* Check continuity counter. */
        if ((h->ts[3] & 0x0F) == h->priv->tscc)
                h->priv->tscc = (h->priv->tscc + 1) & 0x0F;
        else {
                /* TS discontinuity handling: */
                pr_warn("%lu: TS discontinuity: got %#x, expected %#x.\n",
                        h->priv->ts_count, h->ts[3] & 0x0F,
                        h->priv->tscc);
                /* Drop partly decoded SNDU, reset state, resync on PUSI. */
                if (h->priv->ule_skb) {
                        dev_kfree_skb(h->priv->ule_skb);
                        /* Prepare for next SNDU. */
                        // reset_ule(h->priv);  moved to below.
                        h->dev->stats.rx_errors++;
                        h->dev->stats.rx_frame_errors++;
                }
                reset_ule(h->priv);
                /* skip to next PUSI. */
                h->priv->need_pusi = 1;
                return 1;
        }
        /*
         * If we still have an incomplete payload, but PUSI is
         * set; some TS cells are missing.
         * This is only possible here, if we missed exactly 16 TS
         * cells (continuity counter wrap).
         */
        if (h->ts[1] & TS_PUSI) {
                if (!h->priv->need_pusi) {
                        if (!(*h->from_where < (h->ts_remain-1)) ||
                            *h->from_where != h->priv->ule_sndu_remain) {
                                /*
                                 * Pointer field is invalid.
                                 * Drop this TS cell and any started ULE SNDU.
                                 */
                                pr_warn("%lu: Invalid pointer field: %u.\n",
                                        h->priv->ts_count,
                                        *h->from_where);

                                /*
                                 * Drop partly decoded SNDU, reset state,
                                 * resync on PUSI.
                                 */
                                if (h->priv->ule_skb) {
                                        h->error = true;
                                        dev_kfree_skb(h->priv->ule_skb);
                                }

                                if (h->error || h->priv->ule_sndu_remain) {
                                        h->dev->stats.rx_errors++;
                                        h->dev->stats.rx_frame_errors++;
                                        h->error = false;
                                }

                                reset_ule(h->priv);
                                h->priv->need_pusi = 1;
                                return 1;
                        }
                        /*
                         * Skip pointer field (we're processing a
                         * packed payload).
                         */
                        h->from_where += 1;
                        h->ts_remain -= 1;
                } else
                        h->priv->need_pusi = 0;

                if (h->priv->ule_sndu_remain > 183) {
                        /*
                         * Current SNDU lacks more data than there
                         * could be available in the current TS cell.
                         */
                        h->dev->stats.rx_errors++;
                        h->dev->stats.rx_length_errors++;
                        pr_warn("%lu: Expected %d more SNDU bytes, but got PUSI (pf %d, h->ts_remain %d).  Flushing incomplete payload.\n",
                                h->priv->ts_count,
                                h->priv->ule_sndu_remain,
                                h->ts[4], h->ts_remain);
                        dev_kfree_skb(h->priv->ule_skb);
                        /* Prepare for next SNDU. */
                        reset_ule(h->priv);
                        /*
                         * Resync: go to where pointer field points to:
                         * start of next ULE SNDU.
                         */
                        h->from_where += h->ts[4];
                        h->ts_remain -= h->ts[4];
                }
        }
        return 0;
}


/*
 * Start a new payload with skb.
 * Find ULE header.  It is only guaranteed that the
 * length field (2 bytes) is contained in the current
 * TS.
 * Check h.ts_remain has to be >= 2 here.
 */
static int dvb_net_ule_new_payload(struct dvb_net_ule_handle *h)
{
        if (h->ts_remain < 2) {
                pr_warn("Invalid payload packing: only %d bytes left in TS.  Resyncing.\n",
                        h->ts_remain);
                h->priv->ule_sndu_len = 0;
                h->priv->need_pusi = 1;
                h->ts += TS_SZ;
                return 1;
        }

        if (!h->priv->ule_sndu_len) {
                /* Got at least two bytes, thus extrace the SNDU length. */
                h->priv->ule_sndu_len = h->from_where[0] << 8 |
                                        h->from_where[1];
                if (h->priv->ule_sndu_len & 0x8000) {
                        /* D-Bit is set: no dest mac present. */
                        h->priv->ule_sndu_len &= 0x7FFF;
                        h->priv->ule_dbit = 1;
                } else
                        h->priv->ule_dbit = 0;

                if (h->priv->ule_sndu_len < 5) {
                        pr_warn("%lu: Invalid ULE SNDU length %u. Resyncing.\n",
                                h->priv->ts_count,
                                h->priv->ule_sndu_len);
                        h->dev->stats.rx_errors++;
                        h->dev->stats.rx_length_errors++;
                        h->priv->ule_sndu_len = 0;
                        h->priv->need_pusi = 1;
                        h->new_ts = 1;
                        h->ts += TS_SZ;
                        h->priv->ts_count++;
                        return 1;
                }
                h->ts_remain -= 2;      /* consume the 2 bytes SNDU length. */
                h->from_where += 2;
        }

        h->priv->ule_sndu_remain = h->priv->ule_sndu_len + 2;
        /*
         * State of current TS:
         *   h->ts_remain (remaining bytes in the current TS cell)
         *   0  ule_type is not available now, we need the next TS cell
         *   1  the first byte of the ule_type is present
         * >=2  full ULE header present, maybe some payload data as well.
         */
        switch (h->ts_remain) {
        case 1:
                h->priv->ule_sndu_remain--;
                h->priv->ule_sndu_type = h->from_where[0] << 8;

                /* first byte of ule_type is set. */
                h->priv->ule_sndu_type_1 = 1;
                h->ts_remain -= 1;
                h->from_where += 1;
                fallthrough;
        case 0:
                h->new_ts = 1;
                h->ts += TS_SZ;
                h->priv->ts_count++;
                return 1;

        default: /* complete ULE header is present in current TS. */
                /* Extract ULE type field. */
                if (h->priv->ule_sndu_type_1) {
                        h->priv->ule_sndu_type_1 = 0;
                        h->priv->ule_sndu_type |= h->from_where[0];
                        h->from_where += 1; /* points to payload start. */
                        h->ts_remain -= 1;
                } else {
                        /* Complete type is present in new TS. */
                        h->priv->ule_sndu_type = h->from_where[0] << 8 |
                                                 h->from_where[1];
                        h->from_where += 2; /* points to payload start. */
                        h->ts_remain -= 2;
                }
                break;
        }

        /*
         * Allocate the skb (decoder target buffer) with the correct size,
         * as follows:
         *
         * prepare for the largest case: bridged SNDU with MAC address
         * (dbit = 0).
         */
        h->priv->ule_skb = dev_alloc_skb(h->priv->ule_sndu_len +
                                         ETH_HLEN + ETH_ALEN);
        if (!h->priv->ule_skb) {
                pr_notice("%s: Memory squeeze, dropping packet.\n",
                          h->dev->name);
                h->dev->stats.rx_dropped++;
                return -1;
        }

        /* This includes the CRC32 _and_ dest mac, if !dbit. */
        h->priv->ule_sndu_remain = h->priv->ule_sndu_len;
        h->priv->ule_skb->dev = h->dev;
        /*
         * Leave space for Ethernet or bridged SNDU header
         * (eth hdr plus one MAC addr).
         */
        skb_reserve(h->priv->ule_skb, ETH_HLEN + ETH_ALEN);

        return 0;
}


static int dvb_net_ule_should_drop(struct dvb_net_ule_handle *h)
{
        static const u8 bc_addr[ETH_ALEN] = { [0 ... ETH_ALEN - 1] = 0xff };

        /*
         * The destination MAC address is the next data in the skb.  It comes
         * before any extension headers.
         *
         * Check if the payload of this SNDU should be passed up the stack.
         */
        if (h->priv->rx_mode == RX_MODE_PROMISC)
                return 0;

        if (h->priv->ule_skb->data[0] & 0x01) {
                /* multicast or broadcast */
                if (!ether_addr_equal(h->priv->ule_skb->data, bc_addr)) {
                        /* multicast */
                        if (h->priv->rx_mode == RX_MODE_MULTI) {
                                int i;

                                for (i = 0; i < h->priv->multi_num &&
                                     !ether_addr_equal(h->priv->ule_skb->data,
                                                       h->priv->multi_macs[i]);
                                     i++)
                                        ;
                                if (i == h->priv->multi_num)
                                        return 1;
                        } else if (h->priv->rx_mode != RX_MODE_ALL_MULTI)
                                return 1; /* no broadcast; */
                        /*
                         * else:
                         * all multicast mode: accept all multicast packets
                         */
                }
                /* else: broadcast */
        } else if (!ether_addr_equal(h->priv->ule_skb->data, h->dev->dev_addr))
                return 1;

        return 0;
}


static void dvb_net_ule_check_crc(struct dvb_net_ule_handle *h,
                                  struct kvec iov[3],
                                  u32 ule_crc, u32 expected_crc)
{
        u8 dest_addr[ETH_ALEN];

        if (ule_crc != expected_crc) {
                pr_warn("%lu: CRC32 check FAILED: %08x / %08x, SNDU len %d type %#x, ts_remain %d, next 2: %x.\n",
                        h->priv->ts_count, ule_crc, expected_crc,
                        h->priv->ule_sndu_len, h->priv->ule_sndu_type,
                        h->ts_remain,
                        h->ts_remain > 2 ?
                                *(unsigned short *)h->from_where : 0);

        #ifdef DVB_ULE_DEBUG
                hexdump(iov[0].iov_base, iov[0].iov_len);
                hexdump(iov[1].iov_base, iov[1].iov_len);
                hexdump(iov[2].iov_base, iov[2].iov_len);

                if (ule_where == ule_hist) {
                        hexdump(&ule_hist[98*TS_SZ], TS_SZ);
                        hexdump(&ule_hist[99*TS_SZ], TS_SZ);
                } else if (ule_where == &ule_hist[TS_SZ]) {
                        hexdump(&ule_hist[99*TS_SZ], TS_SZ);
                        hexdump(ule_hist, TS_SZ);
                } else {
                        hexdump(ule_where - TS_SZ - TS_SZ, TS_SZ);
                        hexdump(ule_where - TS_SZ, TS_SZ);
                }
                ule_dump = 1;
        #endif

                h->dev->stats.rx_errors++;
                h->dev->stats.rx_crc_errors++;
                dev_kfree_skb(h->priv->ule_skb);

                return;
        }

        /* CRC32 verified OK. */

        /* CRC32 was OK, so remove it from skb. */
        h->priv->ule_skb->tail -= 4;
        h->priv->ule_skb->len -= 4;

        if (!h->priv->ule_dbit) {
                if (dvb_net_ule_should_drop(h)) {
                        netdev_dbg(h->dev,
                                   "Dropping SNDU: MAC destination address does not match: dest addr: %pM, h->dev addr: %pM\n",
                                   h->priv->ule_skb->data, h->dev->dev_addr);
                        dev_kfree_skb(h->priv->ule_skb);
                        return;
                }

                skb_copy_from_linear_data(h->priv->ule_skb, dest_addr,
                                          ETH_ALEN);
                skb_pull(h->priv->ule_skb, ETH_ALEN);
        } else {
                /* dest_addr buffer is only valid if h->priv->ule_dbit == 0 */
                eth_zero_addr(dest_addr);
        }

        /* Handle ULE Extension Headers. */
        if (h->priv->ule_sndu_type < ETH_P_802_3_MIN) {
                /* There is an extension header.  Handle it accordingly. */
                int l = handle_ule_extensions(h->priv);

                if (l < 0) {
                        /*
                         * Mandatory extension header unknown or TEST SNDU.
                         * Drop it.
                         */

                        // pr_warn("Dropping SNDU, extension headers.\n" );
                        dev_kfree_skb(h->priv->ule_skb);
                        return;
                }
                skb_pull(h->priv->ule_skb, l);
        }

        /*
         * Construct/assure correct ethernet header.
         * Note: in bridged mode (h->priv->ule_bridged != 0)
         * we already have the (original) ethernet
         * header at the start of the payload (after
         * optional dest. address and any extension
         * headers).
         */
        if (!h->priv->ule_bridged) {
                skb_push(h->priv->ule_skb, ETH_HLEN);
                h->ethh = (struct ethhdr *)h->priv->ule_skb->data;
                memcpy(h->ethh->h_dest, dest_addr, ETH_ALEN);
                eth_zero_addr(h->ethh->h_source);
                h->ethh->h_proto = htons(h->priv->ule_sndu_type);
        }
        /* else:  skb is in correct state; nothing to do. */
        h->priv->ule_bridged = 0;

        /* Stuff into kernel's protocol stack. */
        h->priv->ule_skb->protocol = dvb_net_eth_type_trans(h->priv->ule_skb,
                                                           h->dev);
        /*
         * If D-bit is set (i.e. destination MAC address not present),
         * receive the packet anyhow.
         */
#if 0
        if (h->priv->ule_dbit && skb->pkt_type == PACKET_OTHERHOST)
                h->priv->ule_skb->pkt_type = PACKET_HOST;
#endif
        h->dev->stats.rx_packets++;
        h->dev->stats.rx_bytes += h->priv->ule_skb->len;
        netif_rx(h->priv->ule_skb);
}

static void dvb_net_ule(struct net_device *dev, const u8 *buf, size_t buf_len)
{
        int ret;
        struct dvb_net_ule_handle h = {
                .dev = dev,
                .priv = netdev_priv(dev),
                .ethh = NULL,
                .buf = buf,
                .buf_len = buf_len,
                .skipped = 0L,
                .ts = NULL,
                .ts_end = NULL,
                .from_where = NULL,
                .ts_remain = 0,
                .how_much = 0,
                .new_ts = 1,
                .error = false,
        };

        /*
         * For all TS cells in current buffer.
         * Appearently, we are called for every single TS cell.
         */
        for (h.ts = h.buf, h.ts_end = h.buf + h.buf_len;
             h.ts < h.ts_end; /* no incr. */) {
                if (h.new_ts) {
                        /* We are about to process a new TS cell. */
                        if (dvb_net_ule_new_ts_cell(&h))
                                continue;
                }

                /* Synchronize on PUSI, if required. */
                if (h.priv->need_pusi) {
                        if (dvb_net_ule_ts_pusi(&h))
                                continue;
                }

                if (h.new_ts) {
                        if (dvb_net_ule_new_ts(&h))
                                continue;
                }

                /* Check if new payload needs to be started. */
                if (h.priv->ule_skb == NULL) {
                        ret = dvb_net_ule_new_payload(&h);
                        if (ret < 0)
                                return;
                        if (ret)
                                continue;
                }

                /* Copy data into our current skb. */
                h.how_much = min(h.priv->ule_sndu_remain, (int)h.ts_remain);
                skb_put_data(h.priv->ule_skb, h.from_where, h.how_much);
                h.priv->ule_sndu_remain -= h.how_much;
                h.ts_remain -= h.how_much;
                h.from_where += h.how_much;

                /* Check for complete payload. */
                if (h.priv->ule_sndu_remain <= 0) {
                        /* Check CRC32, we've got it in our skb already. */
                        __be16 ulen = htons(h.priv->ule_sndu_len);
                        __be16 utype = htons(h.priv->ule_sndu_type);
                        const u8 *tail;
                        struct kvec iov[3] = {
                                { &ulen, sizeof ulen },
                                { &utype, sizeof utype },
                                { h.priv->ule_skb->data,
                                  h.priv->ule_skb->len - 4 }
                        };
                        u32 ule_crc = ~0L, expected_crc;
                        if (h.priv->ule_dbit) {
                                /* Set D-bit for CRC32 verification,
                                 * if it was set originally. */
                                ulen |= htons(0x8000);
                        }

                        ule_crc = iov_crc32(ule_crc, iov, 3);
                        tail = skb_tail_pointer(h.priv->ule_skb);
                        expected_crc = *(tail - 4) << 24 |
                                       *(tail - 3) << 16 |
                                       *(tail - 2) << 8 |
                                       *(tail - 1);

                        dvb_net_ule_check_crc(&h, iov, ule_crc, expected_crc);

                        /* Prepare for next SNDU. */
                        reset_ule(h.priv);
                }

                /* More data in current TS (look at the bytes following the CRC32)? */
                if (h.ts_remain >= 2 && *((unsigned short *)h.from_where) != 0xFFFF) {
                        /* Next ULE SNDU starts right there. */
                        h.new_ts = 0;
                        h.priv->ule_skb = NULL;
                        h.priv->ule_sndu_type_1 = 0;
                        h.priv->ule_sndu_len = 0;
                        // pr_warn("More data in current TS: [%#x %#x %#x %#x]\n",
                        //      *(h.from_where + 0), *(h.from_where + 1),
                        //      *(h.from_where + 2), *(h.from_where + 3));
                        // pr_warn("h.ts @ %p, stopped @ %p:\n", h.ts, h.from_where + 0);
                        // hexdump(h.ts, 188);
                } else {
                        h.new_ts = 1;
                        h.ts += TS_SZ;
                        h.priv->ts_count++;
                        if (h.priv->ule_skb == NULL) {
                                h.priv->need_pusi = 1;
                                h.priv->ule_sndu_type_1 = 0;
                                h.priv->ule_sndu_len = 0;
                        }
                }
        }       /* for all available TS cells */
}

static int dvb_net_ts_callback(const u8 *buffer1, size_t buffer1_len,
                               const u8 *buffer2, size_t buffer2_len,
                               struct dmx_ts_feed *feed,
                               u32 *buffer_flags)
{
        struct net_device *dev = feed->priv;

        if (buffer2)
                pr_warn("buffer2 not NULL: %p.\n", buffer2);
        if (buffer1_len > 32768)
                pr_warn("length > 32k: %zu.\n", buffer1_len);
        /* pr_info("TS callback: %u bytes, %u TS cells @ %p.\n",
                  buffer1_len, buffer1_len / TS_SZ, buffer1); */
        dvb_net_ule(dev, buffer1, buffer1_len);
        return 0;
}


static void dvb_net_sec(struct net_device *dev,
                        const u8 *pkt, int pkt_len)
{
        u8 *eth;
        struct sk_buff *skb;
        struct net_device_stats *stats = &dev->stats;
        int snap = 0;

        /* note: pkt_len includes a 32bit checksum */
        if (pkt_len < 16) {
                pr_warn("%s: IP/MPE packet length = %d too small.\n",
                        dev->name, pkt_len);
                stats->rx_errors++;
                stats->rx_length_errors++;
                return;
        }
/* it seems some ISPs manage to screw up here, so we have to
 * relax the error checks... */
#if 0
        if ((pkt[5] & 0xfd) != 0xc1) {
                /* drop scrambled or broken packets */
#else
        if ((pkt[5] & 0x3c) != 0x00) {
                /* drop scrambled */
#endif
                stats->rx_errors++;
                stats->rx_crc_errors++;
                return;
        }
        if (pkt[5] & 0x02) {
                /* handle LLC/SNAP, see rfc-1042 */
                if (pkt_len < 24 || memcmp(&pkt[12], "\xaa\xaa\x03\0\0\0", 6)) {
                        stats->rx_dropped++;
                        return;
                }
                snap = 8;
        }
        if (pkt[7]) {
                /* FIXME: assemble datagram from multiple sections */
                stats->rx_errors++;
                stats->rx_frame_errors++;
                return;
        }

        /* we have 14 byte ethernet header (ip header follows);
         * 12 byte MPE header; 4 byte checksum; + 2 byte alignment, 8 byte LLC/SNAP
         */
        if (!(skb = dev_alloc_skb(pkt_len - 4 - 12 + 14 + 2 - snap))) {
                //pr_notice("%s: Memory squeeze, dropping packet.\n", dev->name);
                stats->rx_dropped++;
                return;
        }
        skb_reserve(skb, 2);    /* longword align L3 header */
        skb->dev = dev;

        /* copy L3 payload */
        eth = skb_put(skb, pkt_len - 12 - 4 + 14 - snap);
        memcpy(eth + 14, pkt + 12 + snap, pkt_len - 12 - 4 - snap);

        /* create ethernet header: */
        eth[0]=pkt[0x0b];
        eth[1]=pkt[0x0a];
        eth[2]=pkt[0x09];
        eth[3]=pkt[0x08];
        eth[4]=pkt[0x04];
        eth[5]=pkt[0x03];

        eth[6]=eth[7]=eth[8]=eth[9]=eth[10]=eth[11]=0;

        if (snap) {
                eth[12] = pkt[18];
                eth[13] = pkt[19];
        } else {
                /* protocol numbers are from rfc-1700 or
                 * http://www.iana.org/assignments/ethernet-numbers
                 */
                if (pkt[12] >> 4 == 6) { /* version field from IP header */
                        eth[12] = 0x86; /* IPv6 */
                        eth[13] = 0xdd;
                } else {
                        eth[12] = 0x08; /* IPv4 */
                        eth[13] = 0x00;
                }
        }

        skb->protocol = dvb_net_eth_type_trans(skb, dev);

        stats->rx_packets++;
        stats->rx_bytes+=skb->len;
        netif_rx(skb);
}

static int dvb_net_sec_callback(const u8 *buffer1, size_t buffer1_len,
                 const u8 *buffer2, size_t buffer2_len,
                 struct dmx_section_filter *filter, u32 *buffer_flags)
{
        struct net_device *dev = filter->priv;

        /*
         * we rely on the DVB API definition where exactly one complete
         * section is delivered in buffer1
         */
        dvb_net_sec (dev, buffer1, buffer1_len);
        return 0;
}

static netdev_tx_t dvb_net_tx(struct sk_buff *skb, struct net_device *dev)
{
        dev_kfree_skb(skb);
        return NETDEV_TX_OK;
}

static u8 mask_normal[6]={0xff, 0xff, 0xff, 0xff, 0xff, 0xff};
static u8 mask_allmulti[6]={0xff, 0xff, 0xff, 0x00, 0x00, 0x00};
static u8 mac_allmulti[6]={0x01, 0x00, 0x5e, 0x00, 0x00, 0x00};
static u8 mask_promisc[6]={0x00, 0x00, 0x00, 0x00, 0x00, 0x00};

static int dvb_net_filter_sec_set(struct net_device *dev,
                   struct dmx_section_filter **secfilter,
                   const u8 *mac, u8 *mac_mask)
{
        struct dvb_net_priv *priv = netdev_priv(dev);
        int ret;

        *secfilter=NULL;
        ret = priv->secfeed->allocate_filter(priv->secfeed, secfilter);
        if (ret<0) {
                pr_err("%s: could not get filter\n", dev->name);
                return ret;
        }

        (*secfilter)->priv=(void *) dev;

        memset((*secfilter)->filter_value, 0x00, DMX_MAX_FILTER_SIZE);
        memset((*secfilter)->filter_mask,  0x00, DMX_MAX_FILTER_SIZE);
        memset((*secfilter)->filter_mode,  0xff, DMX_MAX_FILTER_SIZE);

        (*secfilter)->filter_value[0]=0x3e;
        (*secfilter)->filter_value[3]=mac[5];
        (*secfilter)->filter_value[4]=mac[4];
        (*secfilter)->filter_value[8]=mac[3];
        (*secfilter)->filter_value[9]=mac[2];
        (*secfilter)->filter_value[10]=mac[1];
        (*secfilter)->filter_value[11]=mac[0];

        (*secfilter)->filter_mask[0] = 0xff;
        (*secfilter)->filter_mask[3] = mac_mask[5];
        (*secfilter)->filter_mask[4] = mac_mask[4];
        (*secfilter)->filter_mask[8] = mac_mask[3];
        (*secfilter)->filter_mask[9] = mac_mask[2];
        (*secfilter)->filter_mask[10] = mac_mask[1];
        (*secfilter)->filter_mask[11]=mac_mask[0];

        netdev_dbg(dev, "filter mac=%pM mask=%pM\n", mac, mac_mask);

        return 0;
}

static int dvb_net_feed_start(struct net_device *dev)
{
        int ret = 0, i;
        struct dvb_net_priv *priv = netdev_priv(dev);
        struct dmx_demux *demux = priv->demux;
        const unsigned char *mac = (const unsigned char *) dev->dev_addr;

        netdev_dbg(dev, "rx_mode %i\n", priv->rx_mode);
        mutex_lock(&priv->mutex);
        if (priv->tsfeed || priv->secfeed || priv->secfilter || priv->multi_secfilter[0])
                pr_err("%s: BUG %d\n", __func__, __LINE__);

        priv->secfeed=NULL;
        priv->secfilter=NULL;
        priv->tsfeed = NULL;

        if (priv->feedtype == DVB_NET_FEEDTYPE_MPE) {
                netdev_dbg(dev, "alloc secfeed\n");
                ret=demux->allocate_section_feed(demux, &priv->secfeed,
                                         dvb_net_sec_callback);
                if (ret<0) {
                        pr_err("%s: could not allocate section feed\n",
                               dev->name);
                        goto error;
                }

                ret = priv->secfeed->set(priv->secfeed, priv->pid, 1);

                if (ret<0) {
                        pr_err("%s: could not set section feed\n", dev->name);
                        priv->demux->release_section_feed(priv->demux, priv->secfeed);
                        priv->secfeed=NULL;
                        goto error;
                }

                if (priv->rx_mode != RX_MODE_PROMISC) {
                        netdev_dbg(dev, "set secfilter\n");
                        dvb_net_filter_sec_set(dev, &priv->secfilter, mac, mask_normal);
                }

                switch (priv->rx_mode) {
                case RX_MODE_MULTI:
                        for (i = 0; i < priv->multi_num; i++) {
                                netdev_dbg(dev, "set multi_secfilter[%d]\n", i);
                                dvb_net_filter_sec_set(dev, &priv->multi_secfilter[i],
                                                       priv->multi_macs[i], mask_normal);
                        }
                        break;
                case RX_MODE_ALL_MULTI:
                        priv->multi_num=1;
                        netdev_dbg(dev, "set multi_secfilter[0]\n");
                        dvb_net_filter_sec_set(dev, &priv->multi_secfilter[0],
                                               mac_allmulti, mask_allmulti);
                        break;
                case RX_MODE_PROMISC:
                        priv->multi_num=0;
                        netdev_dbg(dev, "set secfilter\n");
                        dvb_net_filter_sec_set(dev, &priv->secfilter, mac, mask_promisc);
                        break;
                }

                netdev_dbg(dev, "start filtering\n");
                priv->secfeed->start_filtering(priv->secfeed);
        } else if (priv->feedtype == DVB_NET_FEEDTYPE_ULE) {
                ktime_t timeout = ns_to_ktime(10 * NSEC_PER_MSEC);

                /* we have payloads encapsulated in TS */
                netdev_dbg(dev, "alloc tsfeed\n");
                ret = demux->allocate_ts_feed(demux, &priv->tsfeed, dvb_net_ts_callback);
                if (ret < 0) {
                        pr_err("%s: could not allocate ts feed\n", dev->name);
                        goto error;
                }

                /* Set netdevice pointer for ts decaps callback. */
                priv->tsfeed->priv = (void *)dev;
                ret = priv->tsfeed->set(priv->tsfeed,
                                        priv->pid, /* pid */
                                        TS_PACKET, /* type */
                                        DMX_PES_OTHER, /* pes type */
                                        timeout    /* timeout */
                                        );

                if (ret < 0) {
                        pr_err("%s: could not set ts feed\n", dev->name);
                        priv->demux->release_ts_feed(priv->demux, priv->tsfeed);
                        priv->tsfeed = NULL;
                        goto error;
                }

                netdev_dbg(dev, "start filtering\n");
                priv->tsfeed->start_filtering(priv->tsfeed);
        } else
                ret = -EINVAL;

error:
        mutex_unlock(&priv->mutex);
        return ret;
}

static int dvb_net_feed_stop(struct net_device *dev)
{
        struct dvb_net_priv *priv = netdev_priv(dev);
        int i, ret = 0;

        mutex_lock(&priv->mutex);
        if (priv->feedtype == DVB_NET_FEEDTYPE_MPE) {
                if (priv->secfeed) {
                        if (priv->secfeed->is_filtering) {
                                netdev_dbg(dev, "stop secfeed\n");
                                priv->secfeed->stop_filtering(priv->secfeed);
                        }

                        if (priv->secfilter) {
                                netdev_dbg(dev, "release secfilter\n");
                                priv->secfeed->release_filter(priv->secfeed,
                                                              priv->secfilter);
                                priv->secfilter=NULL;
                        }

                        for (i=0; i<priv->multi_num; i++) {
                                if (priv->multi_secfilter[i]) {
                                        netdev_dbg(dev, "release multi_filter[%d]\n",
                                                   i);
                                        priv->secfeed->release_filter(priv->secfeed,
                                                                      priv->multi_secfilter[i]);
                                        priv->multi_secfilter[i] = NULL;
                                }
                        }

                        priv->demux->release_section_feed(priv->demux, priv->secfeed);
                        priv->secfeed = NULL;
                } else
                        pr_err("%s: no feed to stop\n", dev->name);
        } else if (priv->feedtype == DVB_NET_FEEDTYPE_ULE) {
                if (priv->tsfeed) {
                        if (priv->tsfeed->is_filtering) {
                                netdev_dbg(dev, "stop tsfeed\n");
                                priv->tsfeed->stop_filtering(priv->tsfeed);
                        }
                        priv->demux->release_ts_feed(priv->demux, priv->tsfeed);
                        priv->tsfeed = NULL;
                }
                else
                        pr_err("%s: no ts feed to stop\n", dev->name);
        } else
                ret = -EINVAL;
        mutex_unlock(&priv->mutex);
        return ret;
}


static int dvb_set_mc_filter(struct net_device *dev, unsigned char *addr)
{
        struct dvb_net_priv *priv = netdev_priv(dev);

        if (priv->multi_num == DVB_NET_MULTICAST_MAX)
                return -ENOMEM;

        memcpy(priv->multi_macs[priv->multi_num], addr, ETH_ALEN);

        priv->multi_num++;
        return 0;
}


static void wq_set_multicast_list (struct work_struct *work)
{
        struct dvb_net_priv *priv =
                container_of(work, struct dvb_net_priv, set_multicast_list_wq);
        struct net_device *dev = priv->net;

        dvb_net_feed_stop(dev);
        priv->rx_mode = RX_MODE_UNI;
        netif_addr_lock_bh(dev);

        if (dev->flags & IFF_PROMISC) {
                netdev_dbg(dev, "promiscuous mode\n");
                priv->rx_mode = RX_MODE_PROMISC;
        } else if ((dev->flags & IFF_ALLMULTI)) {
                netdev_dbg(dev, "allmulti mode\n");
                priv->rx_mode = RX_MODE_ALL_MULTI;
        } else if (!netdev_mc_empty(dev)) {
                struct netdev_hw_addr *ha;

                netdev_dbg(dev, "set_mc_list, %d entries\n",
                           netdev_mc_count(dev));

                priv->rx_mode = RX_MODE_MULTI;
                priv->multi_num = 0;

                netdev_for_each_mc_addr(ha, dev)
                        dvb_set_mc_filter(dev, ha->addr);
        }

        netif_addr_unlock_bh(dev);
        dvb_net_feed_start(dev);
}


static void dvb_net_set_multicast_list (struct net_device *dev)
{
        struct dvb_net_priv *priv = netdev_priv(dev);
        schedule_work(&priv->set_multicast_list_wq);
}


static void wq_restart_net_feed (struct work_struct *work)
{
        struct dvb_net_priv *priv =
                container_of(work, struct dvb_net_priv, restart_net_feed_wq);
        struct net_device *dev = priv->net;

        if (netif_running(dev)) {
                dvb_net_feed_stop(dev);
                dvb_net_feed_start(dev);
        }
}


static int dvb_net_set_mac (struct net_device *dev, void *p)
{
        struct dvb_net_priv *priv = netdev_priv(dev);
        struct sockaddr *addr=p;

        eth_hw_addr_set(dev, addr->sa_data);

        if (netif_running(dev))
                schedule_work(&priv->restart_net_feed_wq);

        return 0;
}


static int dvb_net_open(struct net_device *dev)
{
        struct dvb_net_priv *priv = netdev_priv(dev);

        priv->in_use++;
        dvb_net_feed_start(dev);
        return 0;
}


static int dvb_net_stop(struct net_device *dev)
{
        struct dvb_net_priv *priv = netdev_priv(dev);

        priv->in_use--;
        return dvb_net_feed_stop(dev);
}

static const struct header_ops dvb_header_ops = {
        .create         = eth_header,
        .parse          = eth_header_parse,
};


static const struct net_device_ops dvb_netdev_ops = {
        .ndo_open               = dvb_net_open,
        .ndo_stop               = dvb_net_stop,
        .ndo_start_xmit         = dvb_net_tx,
        .ndo_set_rx_mode        = dvb_net_set_multicast_list,
        .ndo_set_mac_address    = dvb_net_set_mac,
        .ndo_validate_addr      = eth_validate_addr,
};

static void dvb_net_setup(struct net_device *dev)
{
        ether_setup(dev);

        dev->header_ops         = &dvb_header_ops;
        dev->netdev_ops         = &dvb_netdev_ops;
        dev->mtu                = 4096;
        dev->max_mtu            = 4096;

        dev->flags |= IFF_NOARP;
}

static int get_if(struct dvb_net *dvbnet)
{
        int i;

        for (i=0; i<DVB_NET_DEVICES_MAX; i++)
                if (!dvbnet->state[i])
                        break;

        if (i == DVB_NET_DEVICES_MAX)
                return -1;

        dvbnet->state[i]=1;
        return i;
}

static int dvb_net_add_if(struct dvb_net *dvbnet, u16 pid, u8 feedtype)
{
        struct net_device *net;
        struct dvb_net_priv *priv;
        int result;
        int if_num;

        if (feedtype != DVB_NET_FEEDTYPE_MPE && feedtype != DVB_NET_FEEDTYPE_ULE)
                return -EINVAL;
        if ((if_num = get_if(dvbnet)) < 0)
                return -EINVAL;

        net = alloc_netdev(sizeof(struct dvb_net_priv), "dvb",
                           NET_NAME_UNKNOWN, dvb_net_setup);
        if (!net)
                return -ENOMEM;

        if (dvbnet->dvbdev->id)
                snprintf(net->name, IFNAMSIZ, "dvb%d%u%d",
                         dvbnet->dvbdev->adapter->num, dvbnet->dvbdev->id, if_num);
        else
                /* compatibility fix to keep dvb0_0 format */
                snprintf(net->name, IFNAMSIZ, "dvb%d_%d",
                         dvbnet->dvbdev->adapter->num, if_num);

        net->addr_len = 6;
        eth_hw_addr_set(net, dvbnet->dvbdev->adapter->proposed_mac);

        dvbnet->device[if_num] = net;

        priv = netdev_priv(net);
        priv->net = net;
        priv->demux = dvbnet->demux;
        priv->pid = pid;
        priv->rx_mode = RX_MODE_UNI;
        priv->need_pusi = 1;
        priv->tscc = 0;
        priv->feedtype = feedtype;
        reset_ule(priv);

        INIT_WORK(&priv->set_multicast_list_wq, wq_set_multicast_list);
        INIT_WORK(&priv->restart_net_feed_wq, wq_restart_net_feed);
        mutex_init(&priv->mutex);

        net->base_addr = pid;

        if ((result = register_netdev(net)) < 0) {
                dvbnet->device[if_num] = NULL;
                free_netdev(net);
                return result;
        }
        pr_info("created network interface %s\n", net->name);

        return if_num;
}

static int dvb_net_remove_if(struct dvb_net *dvbnet, unsigned long num)
{
        struct net_device *net = dvbnet->device[num];
        struct dvb_net_priv *priv;

        if (!dvbnet->state[num])
                return -EINVAL;
        priv = netdev_priv(net);
        if (priv->in_use)
                return -EBUSY;

        dvb_net_stop(net);
        flush_work(&priv->set_multicast_list_wq);
        flush_work(&priv->restart_net_feed_wq);
        pr_info("removed network interface %s\n", net->name);
        unregister_netdev(net);
        dvbnet->state[num]=0;
        dvbnet->device[num] = NULL;
        free_netdev(net);

        return 0;
}

static int dvb_net_do_ioctl(struct file *file,
                  unsigned int cmd, void *parg)
{
        struct dvb_device *dvbdev = file->private_data;
        struct dvb_net *dvbnet = dvbdev->priv;
        int ret = 0;

        if (((file->f_flags&O_ACCMODE)==O_RDONLY))
                return -EPERM;

        if (mutex_lock_interruptible(&dvbnet->ioctl_mutex))
                return -ERESTARTSYS;

        switch (cmd) {
        case NET_ADD_IF:
        {
                struct dvb_net_if *dvbnetif = parg;
                int result;

                if (!capable(CAP_SYS_ADMIN)) {
                        ret = -EPERM;
                        goto ioctl_error;
                }

                if (!try_module_get(dvbdev->adapter->module)) {
                        ret = -EPERM;
                        goto ioctl_error;
                }

                result=dvb_net_add_if(dvbnet, dvbnetif->pid, dvbnetif->feedtype);
                if (result<0) {
                        module_put(dvbdev->adapter->module);
                        ret = result;
                        goto ioctl_error;
                }
                dvbnetif->if_num=result;
                break;
        }
        case NET_GET_IF:
        {
                struct net_device *netdev;
                struct dvb_net_priv *priv_data;
                struct dvb_net_if *dvbnetif = parg;
                int if_num = dvbnetif->if_num;

                if (if_num >= DVB_NET_DEVICES_MAX) {
                        ret = -EINVAL;
                        goto ioctl_error;
                }
                if_num = array_index_nospec(if_num, DVB_NET_DEVICES_MAX);

                if (!dvbnet->state[if_num]) {
                        ret = -EINVAL;
                        goto ioctl_error;
                }

                netdev = dvbnet->device[if_num];

                priv_data = netdev_priv(netdev);
                dvbnetif->pid=priv_data->pid;
                dvbnetif->feedtype=priv_data->feedtype;
                break;
        }
        case NET_REMOVE_IF:
        {
                if (!capable(CAP_SYS_ADMIN)) {
                        ret = -EPERM;
                        goto ioctl_error;
                }
                if ((unsigned long) parg >= DVB_NET_DEVICES_MAX) {
                        ret = -EINVAL;
                        goto ioctl_error;
                }
                ret = dvb_net_remove_if(dvbnet, (unsigned long) parg);
                if (!ret)
                        module_put(dvbdev->adapter->module);
                break;
        }

        /* binary compatibility cruft */
        case __NET_ADD_IF_OLD:
        {
                struct __dvb_net_if_old *dvbnetif = parg;
                int result;

                if (!capable(CAP_SYS_ADMIN)) {
                        ret = -EPERM;
                        goto ioctl_error;
                }

                if (!try_module_get(dvbdev->adapter->module)) {
                        ret = -EPERM;
                        goto ioctl_error;
                }

                result=dvb_net_add_if(dvbnet, dvbnetif->pid, DVB_NET_FEEDTYPE_MPE);
                if (result<0) {
                        module_put(dvbdev->adapter->module);
                        ret = result;
                        goto ioctl_error;
                }
                dvbnetif->if_num=result;
                break;
        }
        case __NET_GET_IF_OLD:
        {
                struct net_device *netdev;
                struct dvb_net_priv *priv_data;
                struct __dvb_net_if_old *dvbnetif = parg;
                int if_num = dvbnetif->if_num;

                if (if_num >= DVB_NET_DEVICES_MAX) {
                        ret = -EINVAL;
                        goto ioctl_error;
                }
                if_num = array_index_nospec(if_num, DVB_NET_DEVICES_MAX);

                if (!dvbnet->state[if_num]) {
                        ret = -EINVAL;
                        goto ioctl_error;
                }

                netdev = dvbnet->device[if_num];

                priv_data = netdev_priv(netdev);
                dvbnetif->pid=priv_data->pid;
                break;
        }
        default:
                ret = -ENOTTY;
                break;
        }

ioctl_error:
        mutex_unlock(&dvbnet->ioctl_mutex);
        return ret;
}

static long dvb_net_ioctl(struct file *file,
              unsigned int cmd, unsigned long arg)
{
        return dvb_usercopy(file, cmd, arg, dvb_net_do_ioctl);
}

static int locked_dvb_net_open(struct inode *inode, struct file *file)
{
        struct dvb_device *dvbdev = file->private_data;
        struct dvb_net *dvbnet = dvbdev->priv;
        int ret;

        if (mutex_lock_interruptible(&dvbnet->remove_mutex))
                return -ERESTARTSYS;

        if (dvbnet->exit) {
                mutex_unlock(&dvbnet->remove_mutex);
                return -ENODEV;
        }

        ret = dvb_generic_open(inode, file);

        mutex_unlock(&dvbnet->remove_mutex);

        return ret;
}

static int dvb_net_close(struct inode *inode, struct file *file)
{
        struct dvb_device *dvbdev = file->private_data;
        struct dvb_net *dvbnet = dvbdev->priv;

        mutex_lock(&dvbnet->remove_mutex);

        dvb_generic_release(inode, file);

        if (dvbdev->users == 1 && dvbnet->exit == 1) {
                mutex_unlock(&dvbnet->remove_mutex);
                wake_up(&dvbdev->wait_queue);
        } else {
                mutex_unlock(&dvbnet->remove_mutex);
        }

        return 0;
}


static const struct file_operations dvb_net_fops = {
        .owner = THIS_MODULE,
        .unlocked_ioctl = dvb_net_ioctl,
        .open = locked_dvb_net_open,
        .release = dvb_net_close,
        .llseek = noop_llseek,
};

static const struct dvb_device dvbdev_net = {
        .priv = NULL,
        .users = 1,
        .writers = 1,
#if defined(CONFIG_MEDIA_CONTROLLER_DVB)
        .name = "dvb-net",
#endif
        .fops = &dvb_net_fops,
};

void dvb_net_release (struct dvb_net *dvbnet)
{
        int i;

        mutex_lock(&dvbnet->remove_mutex);
        dvbnet->exit = 1;
        mutex_unlock(&dvbnet->remove_mutex);

        if (dvbnet->dvbdev->users < 1)
                wait_event(dvbnet->dvbdev->wait_queue,
                                dvbnet->dvbdev->users == 1);

        dvb_unregister_device(dvbnet->dvbdev);

        for (i=0; i<DVB_NET_DEVICES_MAX; i++) {
                if (!dvbnet->state[i])
                        continue;
                dvb_net_remove_if(dvbnet, i);
        }
}
EXPORT_SYMBOL(dvb_net_release);


int dvb_net_init (struct dvb_adapter *adap, struct dvb_net *dvbnet,
                  struct dmx_demux *dmx)
{
        int i;

        mutex_init(&dvbnet->ioctl_mutex);
        mutex_init(&dvbnet->remove_mutex);
        dvbnet->demux = dmx;

        for (i=0; i<DVB_NET_DEVICES_MAX; i++)
                dvbnet->state[i] = 0;

        return dvb_register_device(adap, &dvbnet->dvbdev, &dvbdev_net,
                             dvbnet, DVB_DEVICE_NET, 0);
}
EXPORT_SYMBOL(dvb_net_init);