/*
 * Kernel CAPI interface for the Gigaset driver
 *
 * Copyright (c) 2009 by Tilman Schmidt <tilman@imap.cc>.
 *
 * =====================================================================
 *      This program is free software; you can redistribute it and/or
 *      modify it under the terms of the GNU General Public License as
 *      published by the Free Software Foundation; either version 2 of
 *      the License, or (at your option) any later version.
 * =====================================================================
 */

#include "gigaset.h"
#include <linux/proc_fs.h>
#include <linux/seq_file.h>
#include <linux/ratelimit.h>
#include <linux/isdn/capilli.h>
#include <linux/isdn/capicmd.h>
#include <linux/isdn/capiutil.h>
#include <linux/export.h>

/* missing from kernelcapi.h */
#define CapiNcpiNotSupportedByProtocol  0x0001
#define CapiFlagsNotSupportedByProtocol 0x0002
#define CapiAlertAlreadySent            0x0003
#define CapiFacilitySpecificFunctionNotSupported        0x3011

/* missing from capicmd.h */
#define CAPI_CONNECT_IND_BASELEN        (CAPI_MSG_BASELEN + 4 + 2 + 8 * 1)
#define CAPI_CONNECT_ACTIVE_IND_BASELEN (CAPI_MSG_BASELEN + 4 + 3 * 1)
#define CAPI_CONNECT_B3_IND_BASELEN     (CAPI_MSG_BASELEN + 4 + 1)
#define CAPI_CONNECT_B3_ACTIVE_IND_BASELEN      (CAPI_MSG_BASELEN + 4 + 1)
#define CAPI_DATA_B3_REQ_LEN64          (CAPI_MSG_BASELEN + 4 + 4 + 2 + 2 + 2 + 8)
#define CAPI_DATA_B3_CONF_LEN           (CAPI_MSG_BASELEN + 4 + 2 + 2)
#define CAPI_DISCONNECT_IND_LEN         (CAPI_MSG_BASELEN + 4 + 2)
#define CAPI_DISCONNECT_B3_IND_BASELEN  (CAPI_MSG_BASELEN + 4 + 2 + 1)
#define CAPI_FACILITY_CONF_BASELEN      (CAPI_MSG_BASELEN + 4 + 2 + 2 + 1)
/* most _CONF messages contain only Controller/PLCI/NCCI and Info parameters */
#define CAPI_STDCONF_LEN                (CAPI_MSG_BASELEN + 4 + 2)

#define CAPI_FACILITY_HANDSET   0x0000
#define CAPI_FACILITY_DTMF      0x0001
#define CAPI_FACILITY_V42BIS    0x0002
#define CAPI_FACILITY_SUPPSVC   0x0003
#define CAPI_FACILITY_WAKEUP    0x0004
#define CAPI_FACILITY_LI        0x0005

#define CAPI_SUPPSVC_GETSUPPORTED       0x0000
#define CAPI_SUPPSVC_LISTEN             0x0001

/* missing from capiutil.h */
#define CAPIMSG_PLCI_PART(m)    CAPIMSG_U8(m, 9)
#define CAPIMSG_NCCI_PART(m)    CAPIMSG_U16(m, 10)
#define CAPIMSG_HANDLE_REQ(m)   CAPIMSG_U16(m, 18) /* DATA_B3_REQ/_IND only! */
#define CAPIMSG_FLAGS(m)        CAPIMSG_U16(m, 20)
#define CAPIMSG_SETCONTROLLER(m, contr) capimsg_setu8(m, 8, contr)
#define CAPIMSG_SETPLCI_PART(m, plci)   capimsg_setu8(m, 9, plci)
#define CAPIMSG_SETNCCI_PART(m, ncci)   capimsg_setu16(m, 10, ncci)
#define CAPIMSG_SETFLAGS(m, flags)      capimsg_setu16(m, 20, flags)

/* parameters with differing location in DATA_B3_CONF/_RESP: */
#define CAPIMSG_SETHANDLE_CONF(m, handle)       capimsg_setu16(m, 12, handle)
#define CAPIMSG_SETINFO_CONF(m, info)           capimsg_setu16(m, 14, info)

/* Flags (DATA_B3_REQ/_IND) */
#define CAPI_FLAGS_DELIVERY_CONFIRMATION        0x04
#define CAPI_FLAGS_RESERVED                     (~0x1f)

/* buffer sizes */
#define MAX_BC_OCTETS 11
#define MAX_HLC_OCTETS 3
#define MAX_NUMBER_DIGITS 20
#define MAX_FMT_IE_LEN 20

/* values for bcs->apconnstate */
#define APCONN_NONE     0       /* inactive/listening */
#define APCONN_SETUP    1       /* connecting */
#define APCONN_ACTIVE   2       /* B channel up */

/* registered application data structure */
struct gigaset_capi_appl {
        struct list_head ctrlist;
        struct gigaset_capi_appl *bcnext;
        u16 id;
        struct capi_register_params rp;
        u16 nextMessageNumber;
        u32 listenInfoMask;
        u32 listenCIPmask;
};

/* CAPI specific controller data structure */
struct gigaset_capi_ctr {
        struct capi_ctr ctr;
        struct list_head appls;
        struct sk_buff_head sendqueue;
        atomic_t sendqlen;
        /* two _cmsg structures possibly used concurrently: */
        _cmsg hcmsg;    /* for message composition triggered from hardware */
        _cmsg acmsg;    /* for dissection of messages sent from application */
        u8 bc_buf[MAX_BC_OCTETS + 1];
        u8 hlc_buf[MAX_HLC_OCTETS + 1];
        u8 cgpty_buf[MAX_NUMBER_DIGITS + 3];
        u8 cdpty_buf[MAX_NUMBER_DIGITS + 2];
};

/* CIP Value table (from CAPI 2.0 standard, ch. 6.1) */
static struct {
        u8 *bc;
        u8 *hlc;
} cip2bchlc[] = {
        [1] = { "8090A3", NULL },       /* Speech (A-law) */
        [2] = { "8890", NULL },         /* Unrestricted digital information */
        [3] = { "8990", NULL },         /* Restricted digital information */
        [4] = { "9090A3", NULL },       /* 3,1 kHz audio (A-law) */
        [5] = { "9190", NULL },         /* 7 kHz audio */
        [6] = { "9890", NULL },         /* Video */
        [7] = { "88C0C6E6", NULL },     /* Packet mode */
        [8] = { "8890218F", NULL },     /* 56 kbit/s rate adaptation */
        [9] = { "9190A5", NULL },       /* Unrestricted digital information
                                         * with tones/announcements */
        [16] = { "8090A3", "9181" },    /* Telephony */
        [17] = { "9090A3", "9184" },    /* Group 2/3 facsimile */
        [18] = { "8890", "91A1" },      /* Group 4 facsimile Class 1 */
        [19] = { "8890", "91A4" },      /* Teletex service basic and mixed mode
                                         * and Group 4 facsimile service
                                         * Classes II and III */
        [20] = { "8890", "91A8" },      /* Teletex service basic and
                                         * processable mode */
        [21] = { "8890", "91B1" },      /* Teletex service basic mode */
        [22] = { "8890", "91B2" },      /* International interworking for
                                         * Videotex */
        [23] = { "8890", "91B5" },      /* Telex */
        [24] = { "8890", "91B8" },      /* Message Handling Systems
                                         * in accordance with X.400 */
        [25] = { "8890", "91C1" },      /* OSI application
                                         * in accordance with X.200 */
        [26] = { "9190A5", "9181" },    /* 7 kHz telephony */
        [27] = { "9190A5", "916001" },  /* Video telephony, first connection */
        [28] = { "8890", "916002" },    /* Video telephony, second connection */
};

/*
 * helper functions
 * ================
 */

/*
 * emit unsupported parameter warning
 */
static inline void ignore_cstruct_param(struct cardstate *cs, _cstruct param,
                                        char *msgname, char *paramname)
{
        if (param && *param)
                dev_warn(cs->dev, "%s: ignoring unsupported parameter: %s\n",
                         msgname, paramname);
}

/*
 * convert an IE from Gigaset hex string to ETSI binary representation
 * including length byte
 * return value: result length, -1 on error
 */
static int encode_ie(char *in, u8 *out, int maxlen)
{
        int l = 0;
        while (*in) {
                if (!isxdigit(in[0]) || !isxdigit(in[1]) || l >= maxlen)
                        return -1;
                out[++l] = (hex_to_bin(in[0]) << 4) + hex_to_bin(in[1]);
                in += 2;
        }
        out[0] = l;
        return l;
}

/*
 * convert an IE from ETSI binary representation including length byte
 * to Gigaset hex string
 */
static void decode_ie(u8 *in, char *out)
{
        int i = *in;
        while (i-- > 0) {
                /* ToDo: conversion to upper case necessary? */
                *out++ = toupper(hex_asc_hi(*++in));
                *out++ = toupper(hex_asc_lo(*in));
        }
}

/*
 * retrieve application data structure for an application ID
 */
static inline struct gigaset_capi_appl *
get_appl(struct gigaset_capi_ctr *iif, u16 appl)
{
        struct gigaset_capi_appl *ap;

        list_for_each_entry(ap, &iif->appls, ctrlist)
                if (ap->id == appl)
                        return ap;
        return NULL;
}

/*
 * dump CAPI message to kernel messages for debugging
 */
static inline void dump_cmsg(enum debuglevel level, const char *tag, _cmsg *p)
{
#ifdef CONFIG_GIGASET_DEBUG
        /* dump at most 20 messages in 20 secs */
        static DEFINE_RATELIMIT_STATE(msg_dump_ratelimit, 20 * HZ, 20);
        _cdebbuf *cdb;

        if (!(gigaset_debuglevel & level))
                return;
        if (!___ratelimit(&msg_dump_ratelimit, tag))
                return;

        cdb = capi_cmsg2str(p);
        if (cdb) {
                gig_dbg(level, "%s: [%d] %s", tag, p->ApplId, cdb->buf);
                cdebbuf_free(cdb);
        } else {
                gig_dbg(level, "%s: [%d] %s", tag, p->ApplId,
                        capi_cmd2str(p->Command, p->Subcommand));
        }
#endif
}

static inline void dump_rawmsg(enum debuglevel level, const char *tag,
                               unsigned char *data)
{
#ifdef CONFIG_GIGASET_DEBUG
        char *dbgline;
        int i, l;

        if (!(gigaset_debuglevel & level))
                return;

        l = CAPIMSG_LEN(data);
        if (l < 12) {
                gig_dbg(level, "%s: ??? LEN=%04d", tag, l);
                return;
        }
        gig_dbg(level, "%s: 0x%02x:0x%02x: ID=%03d #0x%04x LEN=%04d NCCI=0x%x",
                tag, CAPIMSG_COMMAND(data), CAPIMSG_SUBCOMMAND(data),
                CAPIMSG_APPID(data), CAPIMSG_MSGID(data), l,
                CAPIMSG_CONTROL(data));
        l -= 12;
        if (l <= 0)
                return;
        if (l > 64)
                l = 64; /* arbitrary limit */
        dbgline = kmalloc(3 * l, GFP_ATOMIC);
        if (!dbgline)
                return;
        for (i = 0; i < l; i++) {
                dbgline[3 * i] = hex_asc_hi(data[12 + i]);
                dbgline[3 * i + 1] = hex_asc_lo(data[12 + i]);
                dbgline[3 * i + 2] = ' ';
        }
        dbgline[3 * l - 1] = '\0';
        gig_dbg(level, "  %s", dbgline);
        kfree(dbgline);
        if (CAPIMSG_COMMAND(data) == CAPI_DATA_B3 &&
            (CAPIMSG_SUBCOMMAND(data) == CAPI_REQ ||
             CAPIMSG_SUBCOMMAND(data) == CAPI_IND)) {
                l = CAPIMSG_DATALEN(data);
                gig_dbg(level, "   DataLength=%d", l);
                if (l <= 0 || !(gigaset_debuglevel & DEBUG_LLDATA))
                        return;
                if (l > 64)
                        l = 64; /* arbitrary limit */
                dbgline = kmalloc(3 * l, GFP_ATOMIC);
                if (!dbgline)
                        return;
                data += CAPIMSG_LEN(data);
                for (i = 0; i < l; i++) {
                        dbgline[3 * i] = hex_asc_hi(data[i]);
                        dbgline[3 * i + 1] = hex_asc_lo(data[i]);
                        dbgline[3 * i + 2] = ' ';
                }
                dbgline[3 * l - 1] = '\0';
                gig_dbg(level, "  %s", dbgline);
                kfree(dbgline);
        }
#endif
}

/*
 * format CAPI IE as string
 */

#ifdef CONFIG_GIGASET_DEBUG
static const char *format_ie(const char *ie)
{
        static char result[3 * MAX_FMT_IE_LEN];
        int len, count;
        char *pout = result;

        if (!ie)
                return "NULL";

        count = len = ie[0];
        if (count > MAX_FMT_IE_LEN)
                count = MAX_FMT_IE_LEN - 1;
        while (count--) {
                *pout++ = hex_asc_hi(*++ie);
                *pout++ = hex_asc_lo(*ie);
                *pout++ = ' ';
        }
        if (len > MAX_FMT_IE_LEN) {
                *pout++ = '.';
                *pout++ = '.';
                *pout++ = '.';
        }
        *--pout = 0;
        return result;
}
#endif

/*
 * emit DATA_B3_CONF message
 */
static void send_data_b3_conf(struct cardstate *cs, struct capi_ctr *ctr,
                              u16 appl, u16 msgid, int channel,
                              u16 handle, u16 info)
{
        struct sk_buff *cskb;
        u8 *msg;

        cskb = alloc_skb(CAPI_DATA_B3_CONF_LEN, GFP_ATOMIC);
        if (!cskb) {
                dev_err(cs->dev, "%s: out of memory\n", __func__);
                return;
        }
        /* frequent message, avoid _cmsg overhead */
        msg = __skb_put(cskb, CAPI_DATA_B3_CONF_LEN);
        CAPIMSG_SETLEN(msg, CAPI_DATA_B3_CONF_LEN);
        CAPIMSG_SETAPPID(msg, appl);
        CAPIMSG_SETCOMMAND(msg, CAPI_DATA_B3);
        CAPIMSG_SETSUBCOMMAND(msg,  CAPI_CONF);
        CAPIMSG_SETMSGID(msg, msgid);
        CAPIMSG_SETCONTROLLER(msg, ctr->cnr);
        CAPIMSG_SETPLCI_PART(msg, channel);
        CAPIMSG_SETNCCI_PART(msg, 1);
        CAPIMSG_SETHANDLE_CONF(msg, handle);
        CAPIMSG_SETINFO_CONF(msg, info);

        /* emit message */
        dump_rawmsg(DEBUG_MCMD, __func__, msg);
        capi_ctr_handle_message(ctr, appl, cskb);
}


/*
 * driver interface functions
 * ==========================
 */

/**
 * gigaset_skb_sent() - acknowledge transmission of outgoing skb
 * @bcs:        B channel descriptor structure.
 * @skb:        sent data.
 *
 * Called by hardware module {bas,ser,usb}_gigaset when the data in a
 * skb has been successfully sent, for signalling completion to the LL.
 */
void gigaset_skb_sent(struct bc_state *bcs, struct sk_buff *dskb)
{
        struct cardstate *cs = bcs->cs;
        struct gigaset_capi_ctr *iif = cs->iif;
        struct gigaset_capi_appl *ap = bcs->ap;
        unsigned char *req = skb_mac_header(dskb);
        u16 flags;

        /* update statistics */
        ++bcs->trans_up;

        if (!ap) {
                gig_dbg(DEBUG_MCMD, "%s: application gone", __func__);
                return;
        }

        /* don't send further B3 messages if disconnected */
        if (bcs->apconnstate < APCONN_ACTIVE) {
                gig_dbg(DEBUG_MCMD, "%s: disconnected", __func__);
                return;
        }

        /*
         * send DATA_B3_CONF if "delivery confirmation" bit was set in request;
         * otherwise it has already been sent by do_data_b3_req()
         */
        flags = CAPIMSG_FLAGS(req);
        if (flags & CAPI_FLAGS_DELIVERY_CONFIRMATION)
                send_data_b3_conf(cs, &iif->ctr, ap->id, CAPIMSG_MSGID(req),
                                  bcs->channel + 1, CAPIMSG_HANDLE_REQ(req),
                                  (flags & ~CAPI_FLAGS_DELIVERY_CONFIRMATION) ?
                                  CapiFlagsNotSupportedByProtocol :
                                  CAPI_NOERROR);
}
EXPORT_SYMBOL_GPL(gigaset_skb_sent);

/**
 * gigaset_skb_rcvd() - pass received skb to LL
 * @bcs:        B channel descriptor structure.
 * @skb:        received data.
 *
 * Called by hardware module {bas,ser,usb}_gigaset when user data has
 * been successfully received, for passing to the LL.
 * Warning: skb must not be accessed anymore!
 */
void gigaset_skb_rcvd(struct bc_state *bcs, struct sk_buff *skb)
{
        struct cardstate *cs = bcs->cs;
        struct gigaset_capi_ctr *iif = cs->iif;
        struct gigaset_capi_appl *ap = bcs->ap;
        int len = skb->len;

        /* update statistics */
        bcs->trans_down++;

        if (!ap) {
                gig_dbg(DEBUG_MCMD, "%s: application gone", __func__);
                dev_kfree_skb_any(skb);
                return;
        }

        /* don't send further B3 messages if disconnected */
        if (bcs->apconnstate < APCONN_ACTIVE) {
                gig_dbg(DEBUG_MCMD, "%s: disconnected", __func__);
                dev_kfree_skb_any(skb);
                return;
        }

        /*
         * prepend DATA_B3_IND message to payload
         * Parameters: NCCI = 1, all others 0/unused
         * frequent message, avoid _cmsg overhead
         */
        skb_push(skb, CAPI_DATA_B3_REQ_LEN);
        CAPIMSG_SETLEN(skb->data, CAPI_DATA_B3_REQ_LEN);
        CAPIMSG_SETAPPID(skb->data, ap->id);
        CAPIMSG_SETCOMMAND(skb->data, CAPI_DATA_B3);
        CAPIMSG_SETSUBCOMMAND(skb->data,  CAPI_IND);
        CAPIMSG_SETMSGID(skb->data, ap->nextMessageNumber++);
        CAPIMSG_SETCONTROLLER(skb->data, iif->ctr.cnr);
        CAPIMSG_SETPLCI_PART(skb->data, bcs->channel + 1);
        CAPIMSG_SETNCCI_PART(skb->data, 1);
        /* Data parameter not used */
        CAPIMSG_SETDATALEN(skb->data, len);
        /* Data handle parameter not used */
        CAPIMSG_SETFLAGS(skb->data, 0);
        /* Data64 parameter not present */

        /* emit message */
        dump_rawmsg(DEBUG_MCMD, __func__, skb->data);
        capi_ctr_handle_message(&iif->ctr, ap->id, skb);
}
EXPORT_SYMBOL_GPL(gigaset_skb_rcvd);

/**
 * gigaset_isdn_rcv_err() - signal receive error
 * @bcs:        B channel descriptor structure.
 *
 * Called by hardware module {bas,ser,usb}_gigaset when a receive error
 * has occurred, for signalling to the LL.
 */
void gigaset_isdn_rcv_err(struct bc_state *bcs)
{
        /* if currently ignoring packets, just count down */
        if (bcs->ignore) {
                bcs->ignore--;
                return;
        }

        /* update statistics */
        bcs->corrupted++;

        /* ToDo: signal error -> LL */
}
EXPORT_SYMBOL_GPL(gigaset_isdn_rcv_err);

/**
 * gigaset_isdn_icall() - signal incoming call
 * @at_state:   connection state structure.
 *
 * Called by main module at tasklet level to notify the LL that an incoming
 * call has been received. @at_state contains the parameters of the call.
 *
 * Return value: call disposition (ICALL_*)
 */
int gigaset_isdn_icall(struct at_state_t *at_state)
{
        struct cardstate *cs = at_state->cs;
        struct bc_state *bcs = at_state->bcs;
        struct gigaset_capi_ctr *iif = cs->iif;
        struct gigaset_capi_appl *ap;
        u32 actCIPmask;
        struct sk_buff *skb;
        unsigned int msgsize;
        unsigned long flags;
        int i;

        /*
         * ToDo: signal calls without a free B channel, too
         * (requires a u8 handle for the at_state structure that can
         * be stored in the PLCI and used in the CONNECT_RESP message
         * handler to retrieve it)
         */
        if (!bcs)
                return ICALL_IGNORE;

        /* prepare CONNECT_IND message, using B channel number as PLCI */
        capi_cmsg_header(&iif->hcmsg, 0, CAPI_CONNECT, CAPI_IND, 0,
                         iif->ctr.cnr | ((bcs->channel + 1) << 8));

        /* minimum size, all structs empty */
        msgsize = CAPI_CONNECT_IND_BASELEN;

        /* Bearer Capability (mandatory) */
        if (at_state->str_var[STR_ZBC]) {
                /* pass on BC from Gigaset */
                if (encode_ie(at_state->str_var[STR_ZBC], iif->bc_buf,
                              MAX_BC_OCTETS) < 0) {
                        dev_warn(cs->dev, "RING ignored - bad BC %s\n",
                                 at_state->str_var[STR_ZBC]);
                        return ICALL_IGNORE;
                }

                /* look up corresponding CIP value */
                iif->hcmsg.CIPValue = 0;        /* default if nothing found */
                for (i = 0; i < ARRAY_SIZE(cip2bchlc); i++)
                        if (cip2bchlc[i].bc != NULL &&
                            cip2bchlc[i].hlc == NULL &&
                            !strcmp(cip2bchlc[i].bc,
                                    at_state->str_var[STR_ZBC])) {
                                iif->hcmsg.CIPValue = i;
                                break;
                        }
        } else {
                /* no BC (internal call): assume CIP 1 (speech, A-law) */
                iif->hcmsg.CIPValue = 1;
                encode_ie(cip2bchlc[1].bc, iif->bc_buf, MAX_BC_OCTETS);
        }
        iif->hcmsg.BC = iif->bc_buf;
        msgsize += iif->hcmsg.BC[0];

        /* High Layer Compatibility (optional) */
        if (at_state->str_var[STR_ZHLC]) {
                /* pass on HLC from Gigaset */
                if (encode_ie(at_state->str_var[STR_ZHLC], iif->hlc_buf,
                              MAX_HLC_OCTETS) < 0) {
                        dev_warn(cs->dev, "RING ignored - bad HLC %s\n",
                                 at_state->str_var[STR_ZHLC]);
                        return ICALL_IGNORE;
                }
                iif->hcmsg.HLC = iif->hlc_buf;
                msgsize += iif->hcmsg.HLC[0];

                /* look up corresponding CIP value */
                /* keep BC based CIP value if none found */
                if (at_state->str_var[STR_ZBC])
                        for (i = 0; i < ARRAY_SIZE(cip2bchlc); i++)
                                if (cip2bchlc[i].hlc != NULL &&
                                    !strcmp(cip2bchlc[i].hlc,
                                            at_state->str_var[STR_ZHLC]) &&
                                    !strcmp(cip2bchlc[i].bc,
                                            at_state->str_var[STR_ZBC])) {
                                        iif->hcmsg.CIPValue = i;
                                        break;
                                }
        }

        /* Called Party Number (optional) */
        if (at_state->str_var[STR_ZCPN]) {
                i = strlen(at_state->str_var[STR_ZCPN]);
                if (i > MAX_NUMBER_DIGITS) {
                        dev_warn(cs->dev, "RING ignored - bad number %s\n",
                                 at_state->str_var[STR_ZBC]);
                        return ICALL_IGNORE;
                }
                iif->cdpty_buf[0] = i + 1;
                iif->cdpty_buf[1] = 0x80; /* type / numbering plan unknown */
                memcpy(iif->cdpty_buf + 2, at_state->str_var[STR_ZCPN], i);
                iif->hcmsg.CalledPartyNumber = iif->cdpty_buf;
                msgsize += iif->hcmsg.CalledPartyNumber[0];
        }

        /* Calling Party Number (optional) */
        if (at_state->str_var[STR_NMBR]) {
                i = strlen(at_state->str_var[STR_NMBR]);
                if (i > MAX_NUMBER_DIGITS) {
                        dev_warn(cs->dev, "RING ignored - bad number %s\n",
                                 at_state->str_var[STR_ZBC]);
                        return ICALL_IGNORE;
                }
                iif->cgpty_buf[0] = i + 2;
                iif->cgpty_buf[1] = 0x00; /* type / numbering plan unknown */
                iif->cgpty_buf[2] = 0x80; /* pres. allowed, not screened */
                memcpy(iif->cgpty_buf + 3, at_state->str_var[STR_NMBR], i);
                iif->hcmsg.CallingPartyNumber = iif->cgpty_buf;
                msgsize += iif->hcmsg.CallingPartyNumber[0];
        }

        /* remaining parameters (not supported, always left NULL):
         * - CalledPartySubaddress
         * - CallingPartySubaddress
         * - AdditionalInfo
         *   - BChannelinformation
         *   - Keypadfacility
         *   - Useruserdata
         *   - Facilitydataarray
         */

        gig_dbg(DEBUG_CMD, "icall: PLCI %x CIP %d BC %s",
                iif->hcmsg.adr.adrPLCI, iif->hcmsg.CIPValue,
                format_ie(iif->hcmsg.BC));
        gig_dbg(DEBUG_CMD, "icall: HLC %s",
                format_ie(iif->hcmsg.HLC));
        gig_dbg(DEBUG_CMD, "icall: CgPty %s",
                format_ie(iif->hcmsg.CallingPartyNumber));
        gig_dbg(DEBUG_CMD, "icall: CdPty %s",
                format_ie(iif->hcmsg.CalledPartyNumber));

        /* scan application list for matching listeners */
        spin_lock_irqsave(&bcs->aplock, flags);
        if (bcs->ap != NULL || bcs->apconnstate != APCONN_NONE) {
                dev_warn(cs->dev, "%s: channel not properly cleared (%p/%d)\n",
                         __func__, bcs->ap, bcs->apconnstate);
                bcs->ap = NULL;
                bcs->apconnstate = APCONN_NONE;
        }
        spin_unlock_irqrestore(&bcs->aplock, flags);
        actCIPmask = 1 | (1 << iif->hcmsg.CIPValue);
        list_for_each_entry(ap, &iif->appls, ctrlist)
                if (actCIPmask & ap->listenCIPmask) {
                        /* build CONNECT_IND message for this application */
                        iif->hcmsg.ApplId = ap->id;
                        iif->hcmsg.Messagenumber = ap->nextMessageNumber++;

                        skb = alloc_skb(msgsize, GFP_ATOMIC);
                        if (!skb) {
                                dev_err(cs->dev, "%s: out of memory\n",
                                        __func__);
                                break;
                        }
                        if (capi_cmsg2message(&iif->hcmsg,
                                              __skb_put(skb, msgsize))) {
                                dev_err(cs->dev, "%s: message parser failure\n",
                                        __func__);
                                dev_kfree_skb_any(skb);
                                break;
                        }
                        dump_cmsg(DEBUG_CMD, __func__, &iif->hcmsg);

                        /* add to listeners on this B channel, update state */
                        spin_lock_irqsave(&bcs->aplock, flags);
                        ap->bcnext = bcs->ap;
                        bcs->ap = ap;
                        bcs->chstate |= CHS_NOTIFY_LL;
                        bcs->apconnstate = APCONN_SETUP;
                        spin_unlock_irqrestore(&bcs->aplock, flags);

                        /* emit message */
                        capi_ctr_handle_message(&iif->ctr, ap->id, skb);
                }

        /*
         * Return "accept" if any listeners.
         * Gigaset will send ALERTING.
         * There doesn't seem to be a way to avoid this.
         */
        return bcs->ap ? ICALL_ACCEPT : ICALL_IGNORE;
}

/*
 * send a DISCONNECT_IND message to an application
 * does not sleep, clobbers the controller's hcmsg structure
 */
static void send_disconnect_ind(struct bc_state *bcs,
                                struct gigaset_capi_appl *ap, u16 reason)
{
        struct cardstate *cs = bcs->cs;
        struct gigaset_capi_ctr *iif = cs->iif;
        struct sk_buff *skb;

        if (bcs->apconnstate == APCONN_NONE)
                return;

        capi_cmsg_header(&iif->hcmsg, ap->id, CAPI_DISCONNECT, CAPI_IND,
                         ap->nextMessageNumber++,
                         iif->ctr.cnr | ((bcs->channel + 1) << 8));
        iif->hcmsg.Reason = reason;
        skb = alloc_skb(CAPI_DISCONNECT_IND_LEN, GFP_ATOMIC);
        if (!skb) {
                dev_err(cs->dev, "%s: out of memory\n", __func__);
                return;
        }
        if (capi_cmsg2message(&iif->hcmsg,
                              __skb_put(skb, CAPI_DISCONNECT_IND_LEN))) {
                dev_err(cs->dev, "%s: message parser failure\n", __func__);
                dev_kfree_skb_any(skb);
                return;
        }
        dump_cmsg(DEBUG_CMD, __func__, &iif->hcmsg);
        capi_ctr_handle_message(&iif->ctr, ap->id, skb);
}

/*
 * send a DISCONNECT_B3_IND message to an application
 * Parameters: NCCI = 1, NCPI empty, Reason_B3 = 0
 * does not sleep, clobbers the controller's hcmsg structure
 */
static void send_disconnect_b3_ind(struct bc_state *bcs,
                                   struct gigaset_capi_appl *ap)
{
        struct cardstate *cs = bcs->cs;
        struct gigaset_capi_ctr *iif = cs->iif;
        struct sk_buff *skb;

        /* nothing to do if no logical connection active */
        if (bcs->apconnstate < APCONN_ACTIVE)
                return;
        bcs->apconnstate = APCONN_SETUP;

        capi_cmsg_header(&iif->hcmsg, ap->id, CAPI_DISCONNECT_B3, CAPI_IND,
                         ap->nextMessageNumber++,
                         iif->ctr.cnr | ((bcs->channel + 1) << 8) | (1 << 16));
        skb = alloc_skb(CAPI_DISCONNECT_B3_IND_BASELEN, GFP_ATOMIC);
        if (!skb) {
                dev_err(cs->dev, "%s: out of memory\n", __func__);
                return;
        }
        if (capi_cmsg2message(&iif->hcmsg,
                          __skb_put(skb, CAPI_DISCONNECT_B3_IND_BASELEN))) {
                dev_err(cs->dev, "%s: message parser failure\n", __func__);
                dev_kfree_skb_any(skb);
                return;
        }
        dump_cmsg(DEBUG_CMD, __func__, &iif->hcmsg);
        capi_ctr_handle_message(&iif->ctr, ap->id, skb);
}

/**
 * gigaset_isdn_connD() - signal D channel connect
 * @bcs:        B channel descriptor structure.
 *
 * Called by main module at tasklet level to notify the LL that the D channel
 * connection has been established.
 */
void gigaset_isdn_connD(struct bc_state *bcs)
{
        struct cardstate *cs = bcs->cs;
        struct gigaset_capi_ctr *iif = cs->iif;
        struct gigaset_capi_appl *ap;
        struct sk_buff *skb;
        unsigned int msgsize;
        unsigned long flags;

        spin_lock_irqsave(&bcs->aplock, flags);
        ap = bcs->ap;
        if (!ap) {
                spin_unlock_irqrestore(&bcs->aplock, flags);
                gig_dbg(DEBUG_CMD, "%s: application gone", __func__);
                return;
        }
        if (bcs->apconnstate == APCONN_NONE) {
                spin_unlock_irqrestore(&bcs->aplock, flags);
                dev_warn(cs->dev, "%s: application %u not connected\n",
                         __func__, ap->id);
                return;
        }
        spin_unlock_irqrestore(&bcs->aplock, flags);
        while (ap->bcnext) {
                /* this should never happen */
                dev_warn(cs->dev, "%s: dropping extra application %u\n",
                         __func__, ap->bcnext->id);
                send_disconnect_ind(bcs, ap->bcnext,
                                    CapiCallGivenToOtherApplication);
                ap->bcnext = ap->bcnext->bcnext;
        }

        /* prepare CONNECT_ACTIVE_IND message
         * Note: LLC not supported by device
         */
        capi_cmsg_header(&iif->hcmsg, ap->id, CAPI_CONNECT_ACTIVE, CAPI_IND,
                         ap->nextMessageNumber++,
                         iif->ctr.cnr | ((bcs->channel + 1) << 8));

        /* minimum size, all structs empty */
        msgsize = CAPI_CONNECT_ACTIVE_IND_BASELEN;

        /* ToDo: set parameter: Connected number
         * (requires ev-layer state machine extension to collect
         * ZCON device reply)
         */

        /* build and emit CONNECT_ACTIVE_IND message */
        skb = alloc_skb(msgsize, GFP_ATOMIC);
        if (!skb) {
                dev_err(cs->dev, "%s: out of memory\n", __func__);
                return;
        }
        if (capi_cmsg2message(&iif->hcmsg, __skb_put(skb, msgsize))) {
                dev_err(cs->dev, "%s: message parser failure\n", __func__);
                dev_kfree_skb_any(skb);
                return;
        }
        dump_cmsg(DEBUG_CMD, __func__, &iif->hcmsg);
        capi_ctr_handle_message(&iif->ctr, ap->id, skb);
}

/**
 * gigaset_isdn_hupD() - signal D channel hangup
 * @bcs:        B channel descriptor structure.
 *
 * Called by main module at tasklet level to notify the LL that the D channel
 * connection has been shut down.
 */
void gigaset_isdn_hupD(struct bc_state *bcs)
{
        struct gigaset_capi_appl *ap;
        unsigned long flags;

        /*
         * ToDo: pass on reason code reported by device
         * (requires ev-layer state machine extension to collect
         * ZCAU device reply)
         */
        spin_lock_irqsave(&bcs->aplock, flags);
        while (bcs->ap != NULL) {
                ap = bcs->ap;
                bcs->ap = ap->bcnext;
                spin_unlock_irqrestore(&bcs->aplock, flags);
                send_disconnect_b3_ind(bcs, ap);
                send_disconnect_ind(bcs, ap, 0);
                spin_lock_irqsave(&bcs->aplock, flags);
        }
        bcs->apconnstate = APCONN_NONE;
        spin_unlock_irqrestore(&bcs->aplock, flags);
}

/**
 * gigaset_isdn_connB() - signal B channel connect
 * @bcs:        B channel descriptor structure.
 *
 * Called by main module at tasklet level to notify the LL that the B channel
 * connection has been established.
 */
void gigaset_isdn_connB(struct bc_state *bcs)
{
        struct cardstate *cs = bcs->cs;
        struct gigaset_capi_ctr *iif = cs->iif;
        struct gigaset_capi_appl *ap;
        struct sk_buff *skb;
        unsigned long flags;
        unsigned int msgsize;
        u8 command;

        spin_lock_irqsave(&bcs->aplock, flags);
        ap = bcs->ap;
        if (!ap) {
                spin_unlock_irqrestore(&bcs->aplock, flags);
                gig_dbg(DEBUG_CMD, "%s: application gone", __func__);
                return;
        }
        if (!bcs->apconnstate) {
                spin_unlock_irqrestore(&bcs->aplock, flags);
                dev_warn(cs->dev, "%s: application %u not connected\n",
                         __func__, ap->id);
                return;
        }

        /*
         * emit CONNECT_B3_ACTIVE_IND if we already got CONNECT_B3_REQ;
         * otherwise we have to emit CONNECT_B3_IND first, and follow up with
         * CONNECT_B3_ACTIVE_IND in reply to CONNECT_B3_RESP
         * Parameters in both cases always: NCCI = 1, NCPI empty
         */
        if (bcs->apconnstate >= APCONN_ACTIVE) {
                command = CAPI_CONNECT_B3_ACTIVE;
                msgsize = CAPI_CONNECT_B3_ACTIVE_IND_BASELEN;
        } else {
                command = CAPI_CONNECT_B3;
                msgsize = CAPI_CONNECT_B3_IND_BASELEN;
        }
        bcs->apconnstate = APCONN_ACTIVE;

        spin_unlock_irqrestore(&bcs->aplock, flags);

        while (ap->bcnext) {
                /* this should never happen */
                dev_warn(cs->dev, "%s: dropping extra application %u\n",
                         __func__, ap->bcnext->id);
                send_disconnect_ind(bcs, ap->bcnext,
                                    CapiCallGivenToOtherApplication);
                ap->bcnext = ap->bcnext->bcnext;
        }

        capi_cmsg_header(&iif->hcmsg, ap->id, command, CAPI_IND,
                         ap->nextMessageNumber++,
                         iif->ctr.cnr | ((bcs->channel + 1) << 8) | (1 << 16));
        skb = alloc_skb(msgsize, GFP_ATOMIC);
        if (!skb) {
                dev_err(cs->dev, "%s: out of memory\n", __func__);
                return;
        }
        if (capi_cmsg2message(&iif->hcmsg, __skb_put(skb, msgsize))) {
                dev_err(cs->dev, "%s: message parser failure\n", __func__);
                dev_kfree_skb_any(skb);
                return;
        }
        dump_cmsg(DEBUG_CMD, __func__, &iif->hcmsg);
        capi_ctr_handle_message(&iif->ctr, ap->id, skb);
}

/**
 * gigaset_isdn_hupB() - signal B channel hangup
 * @bcs:        B channel descriptor structure.
 *
 * Called by main module to notify the LL that the B channel connection has
 * been shut down.
 */
void gigaset_isdn_hupB(struct bc_state *bcs)
{
        struct gigaset_capi_appl *ap = bcs->ap;

        /* ToDo: assure order of DISCONNECT_B3_IND and DISCONNECT_IND ? */

        if (!ap) {
                gig_dbg(DEBUG_CMD, "%s: application gone", __func__);
                return;
        }

        send_disconnect_b3_ind(bcs, ap);
}

/**
 * gigaset_isdn_start() - signal device availability
 * @cs:         device descriptor structure.
 *
 * Called by main module to notify the LL that the device is available for
 * use.
 */
void gigaset_isdn_start(struct cardstate *cs)
{
        struct gigaset_capi_ctr *iif = cs->iif;

        /* fill profile data: manufacturer name */
        strcpy(iif->ctr.manu, "Siemens");
        /* CAPI and device version */
        iif->ctr.version.majorversion = 2;              /* CAPI 2.0 */
        iif->ctr.version.minorversion = 0;
        /* ToDo: check/assert cs->gotfwver? */
        iif->ctr.version.majormanuversion = cs->fwver[0];
        iif->ctr.version.minormanuversion = cs->fwver[1];
        /* number of B channels supported */
        iif->ctr.profile.nbchannel = cs->channels;
        /* global options: internal controller, supplementary services */
        iif->ctr.profile.goptions = 0x11;
        /* B1 protocols: 64 kbit/s HDLC or transparent */
        iif->ctr.profile.support1 =  0x03;
        /* B2 protocols: transparent only */
        /* ToDo: X.75 SLP ? */
        iif->ctr.profile.support2 =  0x02;
        /* B3 protocols: transparent only */
        iif->ctr.profile.support3 =  0x01;
        /* no serial number */
        strcpy(iif->ctr.serial, "0");
        capi_ctr_ready(&iif->ctr);
}

/**
 * gigaset_isdn_stop() - signal device unavailability
 * @cs:         device descriptor structure.
 *
 * Called by main module to notify the LL that the device is no longer
 * available for use.
 */
void gigaset_isdn_stop(struct cardstate *cs)
{
        struct gigaset_capi_ctr *iif = cs->iif;
        capi_ctr_down(&iif->ctr);
}

/*
 * kernel CAPI callback methods
 * ============================
 */

/*
 * register CAPI application
 */
static void gigaset_register_appl(struct capi_ctr *ctr, u16 appl,
                                  capi_register_params *rp)
{
        struct gigaset_capi_ctr *iif

                = container_of(ctr, struct gigaset_capi_ctr, ctr);
        struct cardstate *cs = ctr->driverdata;
        struct gigaset_capi_appl *ap;

        gig_dbg(DEBUG_CMD, "%s [%u] l3cnt=%u blkcnt=%u blklen=%u",
                __func__, appl, rp->level3cnt, rp->datablkcnt, rp->datablklen);

        list_for_each_entry(ap, &iif->appls, ctrlist)
                if (ap->id == appl) {
                        dev_notice(cs->dev,
                                   "application %u already registered\n", appl);
                        return;
                }

        ap = kzalloc(sizeof(*ap), GFP_KERNEL);
        if (!ap) {
                dev_err(cs->dev, "%s: out of memory\n", __func__);
                return;
        }
        ap->id = appl;
        ap->rp = *rp;

        list_add(&ap->ctrlist, &iif->appls);
        dev_info(cs->dev, "application %u registered\n", ap->id);
}

/*
 * remove CAPI application from channel
 * helper function to keep indentation levels down and stay in 80 columns
 */

static inline void remove_appl_from_channel(struct bc_state *bcs,
                                            struct gigaset_capi_appl *ap)
{
        struct cardstate *cs = bcs->cs;
        struct gigaset_capi_appl *bcap;
        unsigned long flags;
        int prevconnstate;

        spin_lock_irqsave(&bcs->aplock, flags);
        bcap = bcs->ap;
        if (bcap == NULL) {
                spin_unlock_irqrestore(&bcs->aplock, flags);
                return;
        }

        /* check first application on channel */
        if (bcap == ap) {
                bcs->ap = ap->bcnext;
                if (bcs->ap != NULL) {
                        spin_unlock_irqrestore(&bcs->aplock, flags);
                        return;
                }

                /* none left, clear channel state */
                prevconnstate = bcs->apconnstate;
                bcs->apconnstate = APCONN_NONE;
                spin_unlock_irqrestore(&bcs->aplock, flags);

                if (prevconnstate == APCONN_ACTIVE) {
                        dev_notice(cs->dev, "%s: hanging up channel %u\n",
                                   __func__, bcs->channel);
                        gigaset_add_event(cs, &bcs->at_state,
                                          EV_HUP, NULL, 0, NULL);
                        gigaset_schedule_event(cs);
                }
                return;
        }

        /* check remaining list */
        do {
                if (bcap->bcnext == ap) {
                        bcap->bcnext = bcap->bcnext->bcnext;
                        spin_unlock_irqrestore(&bcs->aplock, flags);
                        return;
                }
                bcap = bcap->bcnext;
        } while (bcap != NULL);
        spin_unlock_irqrestore(&bcs->aplock, flags);
}

/*
 * release CAPI application
 */
static void gigaset_release_appl(struct capi_ctr *ctr, u16 appl)
{
        struct gigaset_capi_ctr *iif
                = container_of(ctr, struct gigaset_capi_ctr, ctr);
        struct cardstate *cs = iif->ctr.driverdata;
        struct gigaset_capi_appl *ap, *tmp;
        unsigned ch;

        gig_dbg(DEBUG_CMD, "%s [%u]", __func__, appl);

        list_for_each_entry_safe(ap, tmp, &iif->appls, ctrlist)
                if (ap->id == appl) {
                        /* remove from any channels */
                        for (ch = 0; ch < cs->channels; ch++)
                                remove_appl_from_channel(&cs->bcs[ch], ap);

                        /* remove from registration list */
                        list_del(&ap->ctrlist);
                        kfree(ap);
                        dev_info(cs->dev, "application %u released\n", appl);
                }
}

/*
 * =====================================================================
 * outgoing CAPI message handler
 * =====================================================================
 */

/*
 * helper function: emit reply message with given Info value
 */
static void send_conf(struct gigaset_capi_ctr *iif,
                      struct gigaset_capi_appl *ap,
                      struct sk_buff *skb,
                      u16 info)
{
        struct cardstate *cs = iif->ctr.driverdata;

        /*
         * _CONF replies always only have NCCI and Info parameters
         * so they'll fit into the _REQ message skb
         */
        capi_cmsg_answer(&iif->acmsg);
        iif->acmsg.Info = info;
        if (capi_cmsg2message(&iif->acmsg, skb->data)) {
                dev_err(cs->dev, "%s: message parser failure\n", __func__);
                dev_kfree_skb_any(skb);
                return;
        }
        __skb_trim(skb, CAPI_STDCONF_LEN);
        dump_cmsg(DEBUG_CMD, __func__, &iif->acmsg);
        capi_ctr_handle_message(&iif->ctr, ap->id, skb);
}

/*
 * process FACILITY_REQ message
 */
static void do_facility_req(struct gigaset_capi_ctr *iif,
                            struct gigaset_capi_appl *ap,
                            struct sk_buff *skb)
{
        struct cardstate *cs = iif->ctr.driverdata;
        _cmsg *cmsg = &iif->acmsg;
        struct sk_buff *cskb;
        u8 *pparam;
        unsigned int msgsize = CAPI_FACILITY_CONF_BASELEN;
        u16 function, info;
        static u8 confparam[10];        /* max. 9 octets + length byte */

        /* decode message */
        if (capi_message2cmsg(cmsg, skb->data)) {
                dev_err(cs->dev, "%s: message parser failure\n", __func__);
                dev_kfree_skb_any(skb);
                return;
        }
        dump_cmsg(DEBUG_CMD, __func__, cmsg);

        /*
         * Facility Request Parameter is not decoded by capi_message2cmsg()
         * encoding depends on Facility Selector
         */
        switch (cmsg->FacilitySelector) {
        case CAPI_FACILITY_DTMF:        /* ToDo */
                info = CapiFacilityNotSupported;
                confparam[0] = 2;       /* length */
                /* DTMF information: Unknown DTMF request */
                capimsg_setu16(confparam, 1, 2);
                break;

        case CAPI_FACILITY_V42BIS:      /* not supported */
                info = CapiFacilityNotSupported;
                confparam[0] = 2;       /* length */
                /* V.42 bis information: not available */
                capimsg_setu16(confparam, 1, 1);
                break;

        case CAPI_FACILITY_SUPPSVC:
                /* decode Function parameter */
                pparam = cmsg->FacilityRequestParameter;
                if (pparam == NULL || pparam[0] < 2) {
                        dev_notice(cs->dev, "%s: %s missing\n", "FACILITY_REQ",
                                   "Facility Request Parameter");
                        send_conf(iif, ap, skb, CapiIllMessageParmCoding);
                        return;
                }
                function = CAPIMSG_U16(pparam, 1);
                switch (function) {
                case CAPI_SUPPSVC_GETSUPPORTED:
                        info = CapiSuccess;
                        /* Supplementary Service specific parameter */
                        confparam[3] = 6;       /* length */
                        /* Supplementary services info: Success */
                        capimsg_setu16(confparam, 4, CapiSuccess);
                        /* Supported Services: none */
                        capimsg_setu32(confparam, 6, 0);
                        break;
                case CAPI_SUPPSVC_LISTEN:
                        if (pparam[0] < 7 || pparam[3] < 4) {
                                dev_notice(cs->dev, "%s: %s missing\n",
                                           "FACILITY_REQ", "Notification Mask");
                                send_conf(iif, ap, skb,
                                          CapiIllMessageParmCoding);
                                return;
                        }
                        if (CAPIMSG_U32(pparam, 4) != 0) {
                                dev_notice(cs->dev,
                                           "%s: unsupported supplementary service notification mask 0x%x\n",
                                           "FACILITY_REQ", CAPIMSG_U32(pparam, 4));
                                info = CapiFacilitySpecificFunctionNotSupported;
                                confparam[3] = 2;       /* length */
                                capimsg_setu16(confparam, 4,
                                               CapiSupplementaryServiceNotSupported);
                                break;
                        }
                        info = CapiSuccess;
                        confparam[3] = 2;       /* length */
                        capimsg_setu16(confparam, 4, CapiSuccess);
                        break;

                /* ToDo: add supported services */

                default:
                        dev_notice(cs->dev,
                                   "%s: unsupported supplementary service function 0x%04x\n",
                                   "FACILITY_REQ", function);
                        info = CapiFacilitySpecificFunctionNotSupported;
                        /* Supplementary Service specific parameter */
                        confparam[3] = 2;       /* length */
                        /* Supplementary services info: not supported */
                        capimsg_setu16(confparam, 4,
                                       CapiSupplementaryServiceNotSupported);
                }

                /* Facility confirmation parameter */
                confparam[0] = confparam[3] + 3;        /* total length */
                /* Function: copy from _REQ message */
                capimsg_setu16(confparam, 1, function);
                /* Supplementary Service specific parameter already set above */
                break;

        case CAPI_FACILITY_WAKEUP:      /* ToDo */
                info = CapiFacilityNotSupported;
                confparam[0] = 2;       /* length */
                /* Number of accepted awake request parameters: 0 */
                capimsg_setu16(confparam, 1, 0);
                break;

        default:
                info = CapiFacilityNotSupported;
                confparam[0] = 0;       /* empty struct */
        }

        /* send FACILITY_CONF with given Info and confirmation parameter */
        dev_kfree_skb_any(skb);
        capi_cmsg_answer(cmsg);
        cmsg->Info = info;
        cmsg->FacilityConfirmationParameter = confparam;
        msgsize += confparam[0];        /* length */
        cskb = alloc_skb(msgsize, GFP_ATOMIC);
        if (!cskb) {
                dev_err(cs->dev, "%s: out of memory\n", __func__);
                return;
        }
        if (capi_cmsg2message(cmsg, __skb_put(cskb, msgsize))) {
                dev_err(cs->dev, "%s: message parser failure\n", __func__);
                dev_kfree_skb_any(cskb);
                return;
        }
        dump_cmsg(DEBUG_CMD, __func__, cmsg);
        capi_ctr_handle_message(&iif->ctr, ap->id, cskb);
}


/*
 * process LISTEN_REQ message
 * just store the masks in the application data structure
 */
static void do_listen_req(struct gigaset_capi_ctr *iif,
                          struct gigaset_capi_appl *ap,
                          struct sk_buff *skb)
{
        struct cardstate *cs = iif->ctr.driverdata;

        /* decode message */
        if (capi_message2cmsg(&iif->acmsg, skb->data)) {
                dev_err(cs->dev, "%s: message parser failure\n", __func__);
                dev_kfree_skb_any(skb);
                return;
        }
        dump_cmsg(DEBUG_CMD, __func__, &iif->acmsg);

        /* store listening parameters */
        ap->listenInfoMask = iif->acmsg.InfoMask;
        ap->listenCIPmask = iif->acmsg.CIPmask;
        send_conf(iif, ap, skb, CapiSuccess);
}

/*
 * process ALERT_REQ message
 * nothing to do, Gigaset always alerts anyway
 */
static void do_alert_req(struct gigaset_capi_ctr *iif,
                         struct gigaset_capi_appl *ap,
                         struct sk_buff *skb)
{
        struct cardstate *cs = iif->ctr.driverdata;

        /* decode message */
        if (capi_message2cmsg(&iif->acmsg, skb->data)) {
                dev_err(cs->dev, "%s: message parser failure\n", __func__);
                dev_kfree_skb_any(skb);
                return;
        }
        dump_cmsg(DEBUG_CMD, __func__, &iif->acmsg);
        send_conf(iif, ap, skb, CapiAlertAlreadySent);
}

/*
 * process CONNECT_REQ message
 * allocate a B channel, prepare dial commands, queue a DIAL event,
 * emit CONNECT_CONF reply
 */
static void do_connect_req(struct gigaset_capi_ctr *iif,
                           struct gigaset_capi_appl *ap,
                           struct sk_buff *skb)
{
        struct cardstate *cs = iif->ctr.driverdata;
        _cmsg *cmsg = &iif->acmsg;
        struct bc_state *bcs;
        char **commands;
        char *s;
        u8 *pp;
        unsigned long flags;
        int i, l, lbc, lhlc;
        u16 info;

        /* decode message */
        if (capi_message2cmsg(cmsg, skb->data)) {
                dev_err(cs->dev, "%s: message parser failure\n", __func__);
                dev_kfree_skb_any(skb);
                return;
        }
        dump_cmsg(DEBUG_CMD, __func__, cmsg);

        /* get free B channel & construct PLCI */
        bcs = gigaset_get_free_channel(cs);
        if (!bcs) {
                dev_notice(cs->dev, "%s: no B channel available\n",
                           "CONNECT_REQ");
                send_conf(iif, ap, skb, CapiNoPlciAvailable);
                return;
        }
        spin_lock_irqsave(&bcs->aplock, flags);
        if (bcs->ap != NULL || bcs->apconnstate != APCONN_NONE)
                dev_warn(cs->dev, "%s: channel not properly cleared (%p/%d)\n",
                         __func__, bcs->ap, bcs->apconnstate);
        ap->bcnext = NULL;
        bcs->ap = ap;
        bcs->apconnstate = APCONN_SETUP;
        spin_unlock_irqrestore(&bcs->aplock, flags);

        bcs->rx_bufsize = ap->rp.datablklen;
        dev_kfree_skb(bcs->rx_skb);
        gigaset_new_rx_skb(bcs);
        cmsg->adr.adrPLCI |= (bcs->channel + 1) << 8;

        /* build command table */
        commands = kzalloc(AT_NUM * (sizeof *commands), GFP_KERNEL);
        if (!commands)
                goto oom;

        /* encode parameter: Called party number */
        pp = cmsg->CalledPartyNumber;
        if (pp == NULL || *pp == 0) {
                dev_notice(cs->dev, "%s: %s missing\n",
                           "CONNECT_REQ", "Called party number");
                info = CapiIllMessageParmCoding;
                goto error;
        }
        l = *pp++;
        /* check type of number/numbering plan byte */
        switch (*pp) {
        case 0x80:      /* unknown type / unknown numbering plan */
        case 0x81:      /* unknown type / ISDN/Telephony numbering plan */
                break;
        default:        /* others: warn about potential misinterpretation */
                dev_notice(cs->dev, "%s: %s type/plan 0x%02x unsupported\n",
                           "CONNECT_REQ", "Called party number", *pp);
        }
        pp++;
        l--;
        /* translate "**" internal call prefix to CTP value */
        if (l >= 2 && pp[0] == '*' && pp[1] == '*') {
                s = "^SCTP=0\r";
                pp += 2;
                l -= 2;
        } else {
                s = "^SCTP=1\r";
        }
        commands[AT_TYPE] = kstrdup(s, GFP_KERNEL);
        if (!commands[AT_TYPE])
                goto oom;
        commands[AT_DIAL] = kmalloc(l + 3, GFP_KERNEL);
        if (!commands[AT_DIAL])
                goto oom;
        snprintf(commands[AT_DIAL], l + 3, "D%.*s\r", l, pp);

        /* encode parameter: Calling party number */
        pp = cmsg->CallingPartyNumber;
        if (pp != NULL && *pp > 0) {
                l = *pp++;

                /* check type of number/numbering plan byte */
                /* ToDo: allow for/handle Ext=1? */
                switch (*pp) {
                case 0x00:      /* unknown type / unknown numbering plan */
                case 0x01:      /* unknown type / ISDN/Telephony num. plan */
                        break;
                default:
                        dev_notice(cs->dev,
                                   "%s: %s type/plan 0x%02x unsupported\n",
                                   "CONNECT_REQ", "Calling party number", *pp);
                }
                pp++;
                l--;

                /* check presentation indicator */
                if (!l) {
                        dev_notice(cs->dev, "%s: %s IE truncated\n",
                                   "CONNECT_REQ", "Calling party number");
                        info = CapiIllMessageParmCoding;
                        goto error;
                }
                switch (*pp & 0xfc) { /* ignore Screening indicator */
                case 0x80:      /* Presentation allowed */
                        s = "^SCLIP=1\r";
                        break;
                case 0xa0:      /* Presentation restricted */
                        s = "^SCLIP=0\r";
                        break;
                default:
                        dev_notice(cs->dev, "%s: invalid %s 0x%02x\n",
                                   "CONNECT_REQ",
                                   "Presentation/Screening indicator",
                                   *pp);
                        s = "^SCLIP=1\r";
                }
                commands[AT_CLIP] = kstrdup(s, GFP_KERNEL);
                if (!commands[AT_CLIP])
                        goto oom;
                pp++;
                l--;

                if (l) {
                        /* number */
                        commands[AT_MSN] = kmalloc(l + 8, GFP_KERNEL);
                        if (!commands[AT_MSN])
                                goto oom;
                        snprintf(commands[AT_MSN], l + 8, "^SMSN=%*s\r", l, pp);
                }
        }

        /* check parameter: CIP Value */
        if (cmsg->CIPValue >= ARRAY_SIZE(cip2bchlc) ||
            (cmsg->CIPValue > 0 && cip2bchlc[cmsg->CIPValue].bc == NULL)) {
                dev_notice(cs->dev, "%s: unknown CIP value %d\n",
                           "CONNECT_REQ", cmsg->CIPValue);
                info = CapiCipValueUnknown;
                goto error;
        }

        /*
         * check/encode parameters: BC & HLC
         * must be encoded together as device doesn't accept HLC separately
         * explicit parameters override values derived from CIP
         */

        /* determine lengths */
        if (cmsg->BC && cmsg->BC[0])            /* BC specified explicitly */
                lbc = 2 * cmsg->BC[0];
        else if (cip2bchlc[cmsg->CIPValue].bc)  /* BC derived from CIP */
                lbc = strlen(cip2bchlc[cmsg->CIPValue].bc);
        else                                    /* no BC */
                lbc = 0;
        if (cmsg->HLC && cmsg->HLC[0])          /* HLC specified explicitly */
                lhlc = 2 * cmsg->HLC[0];
        else if (cip2bchlc[cmsg->CIPValue].hlc) /* HLC derived from CIP */
                lhlc = strlen(cip2bchlc[cmsg->CIPValue].hlc);
        else                                    /* no HLC */
                lhlc = 0;

        if (lbc) {
                /* have BC: allocate and assemble command string */
                l = lbc + 7;            /* "^SBC=" + value + "\r" + null byte */
                if (lhlc)
                        l += lhlc + 7;  /* ";^SHLC=" + value */
                commands[AT_BC] = kmalloc(l, GFP_KERNEL);
                if (!commands[AT_BC])
                        goto oom;
                strcpy(commands[AT_BC], "^SBC=");
                if (cmsg->BC && cmsg->BC[0])    /* BC specified explicitly */
                        decode_ie(cmsg->BC, commands[AT_BC] + 5);
                else                            /* BC derived from CIP */
                        strcpy(commands[AT_BC] + 5,
                               cip2bchlc[cmsg->CIPValue].bc);
                if (lhlc) {
                        strcpy(commands[AT_BC] + lbc + 5, ";^SHLC=");
                        if (cmsg->HLC && cmsg->HLC[0])
                                /* HLC specified explicitly */
                                decode_ie(cmsg->HLC,
                                          commands[AT_BC] + lbc + 12);
                        else    /* HLC derived from CIP */
                                strcpy(commands[AT_BC] + lbc + 12,
                                       cip2bchlc[cmsg->CIPValue].hlc);
                }
                strcpy(commands[AT_BC] + l - 2, "\r");
        } else {
                /* no BC */
                if (lhlc) {
                        dev_notice(cs->dev, "%s: cannot set HLC without BC\n",
                                   "CONNECT_REQ");
                        info = CapiIllMessageParmCoding; /* ? */
                        goto error;
                }
        }

        /* check/encode parameter: B Protocol */
        if (cmsg->BProtocol == CAPI_DEFAULT) {
                bcs->proto2 = L2_HDLC;
                dev_warn(cs->dev,
                         "B2 Protocol X.75 SLP unsupported, using Transparent\n");
        } else {
                switch (cmsg->B1protocol) {
                case 0:
                        bcs->proto2 = L2_HDLC;
                        break;
                case 1:
                        bcs->proto2 = L2_VOICE;
                        break;
                default:
                        dev_warn(cs->dev,
                                 "B1 Protocol %u unsupported, using Transparent\n",
                                 cmsg->B1protocol);
                        bcs->proto2 = L2_VOICE;
                }
                if (cmsg->B2protocol != 1)
                        dev_warn(cs->dev,
                                 "B2 Protocol %u unsupported, using Transparent\n",
                                 cmsg->B2protocol);
                if (cmsg->B3protocol != 0)
                        dev_warn(cs->dev,
                                 "B3 Protocol %u unsupported, using Transparent\n",
                                 cmsg->B3protocol);
                ignore_cstruct_param(cs, cmsg->B1configuration,
                                     "CONNECT_REQ", "B1 Configuration");
                ignore_cstruct_param(cs, cmsg->B2configuration,
                                     "CONNECT_REQ", "B2 Configuration");
                ignore_cstruct_param(cs, cmsg->B3configuration,
                                     "CONNECT_REQ", "B3 Configuration");
        }
        commands[AT_PROTO] = kmalloc(9, GFP_KERNEL);
        if (!commands[AT_PROTO])
                goto oom;
        snprintf(commands[AT_PROTO], 9, "^SBPR=%u\r", bcs->proto2);

        /* ToDo: check/encode remaining parameters */
        ignore_cstruct_param(cs, cmsg->CalledPartySubaddress,
                             "CONNECT_REQ", "Called pty subaddr");
        ignore_cstruct_param(cs, cmsg->CallingPartySubaddress,
                             "CONNECT_REQ", "Calling pty subaddr");
        ignore_cstruct_param(cs, cmsg->LLC,
                             "CONNECT_REQ", "LLC");
        if (cmsg->AdditionalInfo != CAPI_DEFAULT) {
                ignore_cstruct_param(cs, cmsg->BChannelinformation,
                                     "CONNECT_REQ", "B Channel Information");
                ignore_cstruct_param(cs, cmsg->Keypadfacility,
                                     "CONNECT_REQ", "Keypad Facility");
                ignore_cstruct_param(cs, cmsg->Useruserdata,
                                     "CONNECT_REQ", "User-User Data");
                ignore_cstruct_param(cs, cmsg->Facilitydataarray,
                                     "CONNECT_REQ", "Facility Data Array");
        }

        /* encode parameter: B channel to use */
        commands[AT_ISO] = kmalloc(9, GFP_KERNEL);
        if (!commands[AT_ISO])
                goto oom;
        snprintf(commands[AT_ISO], 9, "^SISO=%u\r",
                 (unsigned) bcs->channel + 1);

        /* queue & schedule EV_DIAL event */
        if (!gigaset_add_event(cs, &bcs->at_state, EV_DIAL, commands,
                               bcs->at_state.seq_index, NULL)) {
                info = CAPI_MSGOSRESOURCEERR;
                goto error;
        }
        gigaset_schedule_event(cs);
        send_conf(iif, ap, skb, CapiSuccess);
        return;

oom:
        dev_err(cs->dev, "%s: out of memory\n", __func__);
        info = CAPI_MSGOSRESOURCEERR;
error:
        if (commands)
                for (i = 0; i < AT_NUM; i++)
                        kfree(commands[i]);
        kfree(commands);
        gigaset_free_channel(bcs);
        send_conf(iif, ap, skb, info);
}

/*
 * process CONNECT_RESP message
 * checks protocol parameters and queues an ACCEPT or HUP event
 */
static void do_connect_resp(struct gigaset_capi_ctr *iif,
                            struct gigaset_capi_appl *ap,
                            struct sk_buff *skb)
{
        struct cardstate *cs = iif->ctr.driverdata;
        _cmsg *cmsg = &iif->acmsg;
        struct bc_state *bcs;
        struct gigaset_capi_appl *oap;
        unsigned long flags;
        int channel;

        /* decode message */
        if (capi_message2cmsg(cmsg, skb->data)) {
                dev_err(cs->dev, "%s: message parser failure\n", __func__);
                dev_kfree_skb_any(skb);
                return;
        }
        dump_cmsg(DEBUG_CMD, __func__, cmsg);
        dev_kfree_skb_any(skb);

        /* extract and check channel number from PLCI */
        channel = (cmsg->adr.adrPLCI >> 8) & 0xff;
        if (!channel || channel > cs->channels) {
                dev_notice(cs->dev, "%s: invalid %s 0x%02x\n",
                           "CONNECT_RESP", "PLCI", cmsg->adr.adrPLCI);
                return;
        }
        bcs = cs->bcs + channel - 1;

        switch (cmsg->Reject) {
        case 0:         /* Accept */
                /* drop all competing applications, keep only this one */
                spin_lock_irqsave(&bcs->aplock, flags);
                while (bcs->ap != NULL) {
                        oap = bcs->ap;
                        bcs->ap = oap->bcnext;
                        if (oap != ap) {
                                spin_unlock_irqrestore(&bcs->aplock, flags);
                                send_disconnect_ind(bcs, oap,
                                                    CapiCallGivenToOtherApplication);
                                spin_lock_irqsave(&bcs->aplock, flags);
                        }
                }
                ap->bcnext = NULL;
                bcs->ap = ap;
                spin_unlock_irqrestore(&bcs->aplock, flags);

                bcs->rx_bufsize = ap->rp.datablklen;
                dev_kfree_skb(bcs->rx_skb);
                gigaset_new_rx_skb(bcs);
                bcs->chstate |= CHS_NOTIFY_LL;

                /* check/encode B channel protocol */
                if (cmsg->BProtocol == CAPI_DEFAULT) {
                        bcs->proto2 = L2_HDLC;
                        dev_warn(cs->dev,
                                 "B2 Protocol X.75 SLP unsupported, using Transparent\n");
                } else {
                        switch (cmsg->B1protocol) {
                        case 0:
                                bcs->proto2 = L2_HDLC;
                                break;
                        case 1:
                                bcs->proto2 = L2_VOICE;
                                break;
                        default:
                                dev_warn(cs->dev,
                                         "B1 Protocol %u unsupported, using Transparent\n",
                                         cmsg->B1protocol);
                                bcs->proto2 = L2_VOICE;
                        }
                        if (cmsg->B2protocol != 1)
                                dev_warn(cs->dev,
                                         "B2 Protocol %u unsupported, using Transparent\n",
                                         cmsg->B2protocol);
                        if (cmsg->B3protocol != 0)
                                dev_warn(cs->dev,
                                         "B3 Protocol %u unsupported, using Transparent\n",
                                         cmsg->B3protocol);
                        ignore_cstruct_param(cs, cmsg->B1configuration,
                                             "CONNECT_RESP", "B1 Configuration");
                        ignore_cstruct_param(cs, cmsg->B2configuration,
                                             "CONNECT_RESP", "B2 Configuration");
                        ignore_cstruct_param(cs, cmsg->B3configuration,
                                             "CONNECT_RESP", "B3 Configuration");
                }

                /* ToDo: check/encode remaining parameters */
                ignore_cstruct_param(cs, cmsg->ConnectedNumber,
                                     "CONNECT_RESP", "Connected Number");
                ignore_cstruct_param(cs, cmsg->ConnectedSubaddress,
                                     "CONNECT_RESP", "Connected Subaddress");
                ignore_cstruct_param(cs, cmsg->LLC,
                                     "CONNECT_RESP", "LLC");
                if (cmsg->AdditionalInfo != CAPI_DEFAULT) {
                        ignore_cstruct_param(cs, cmsg->BChannelinformation,
                                             "CONNECT_RESP", "BChannel Information");
                        ignore_cstruct_param(cs, cmsg->Keypadfacility,
                                             "CONNECT_RESP", "Keypad Facility");
                        ignore_cstruct_param(cs, cmsg->Useruserdata,
                                             "CONNECT_RESP", "User-User Data");
                        ignore_cstruct_param(cs, cmsg->Facilitydataarray,
                                             "CONNECT_RESP", "Facility Data Array");
                }

                /* Accept call */
                if (!gigaset_add_event(cs, &cs->bcs[channel - 1].at_state,
                                       EV_ACCEPT, NULL, 0, NULL))
                        return;
                gigaset_schedule_event(cs);
                return;

        case 1:                 /* Ignore */
                /* send DISCONNECT_IND to this application */
                send_disconnect_ind(bcs, ap, 0);

                /* remove it from the list of listening apps */
                spin_lock_irqsave(&bcs->aplock, flags);
                if (bcs->ap == ap) {
                        bcs->ap = ap->bcnext;
                        if (bcs->ap == NULL) {
                                /* last one: stop ev-layer hupD notifications */
                                bcs->apconnstate = APCONN_NONE;
                                bcs->chstate &= ~CHS_NOTIFY_LL;
                        }
                        spin_unlock_irqrestore(&bcs->aplock, flags);
                        return;
                }
                for (oap = bcs->ap; oap != NULL; oap = oap->bcnext) {
                        if (oap->bcnext == ap) {
                                oap->bcnext = oap->bcnext->bcnext;
                                spin_unlock_irqrestore(&bcs->aplock, flags);
                                return;
                        }
                }
                spin_unlock_irqrestore(&bcs->aplock, flags);
                dev_err(cs->dev, "%s: application %u not found\n",
                        __func__, ap->id);
                return;

        default:                /* Reject */
                /* drop all competing applications, keep only this one */
                spin_lock_irqsave(&bcs->aplock, flags);
                while (bcs->ap != NULL) {
                        oap = bcs->ap;
                        bcs->ap = oap->bcnext;
                        if (oap != ap) {
                                spin_unlock_irqrestore(&bcs->aplock, flags);
                                send_disconnect_ind(bcs, oap,
                                                    CapiCallGivenToOtherApplication);
                                spin_lock_irqsave(&bcs->aplock, flags);
                        }
                }
                ap->bcnext = NULL;
                bcs->ap = ap;
                spin_unlock_irqrestore(&bcs->aplock, flags);

                /* reject call - will trigger DISCONNECT_IND for this app */
                dev_info(cs->dev, "%s: Reject=%x\n",
                         "CONNECT_RESP", cmsg->Reject);
                if (!gigaset_add_event(cs, &cs->bcs[channel - 1].at_state,
                                       EV_HUP, NULL, 0, NULL))
                        return;
                gigaset_schedule_event(cs);
                return;
        }
}

/*
 * process CONNECT_B3_REQ message
 * build NCCI and emit CONNECT_B3_CONF reply
 */
static void do_connect_b3_req(struct gigaset_capi_ctr *iif,
                              struct gigaset_capi_appl *ap,
                              struct sk_buff *skb)
{
        struct cardstate *cs = iif->ctr.driverdata;
        _cmsg *cmsg = &iif->acmsg;
        struct bc_state *bcs;
        int channel;

        /* decode message */
        if (capi_message2cmsg(cmsg, skb->data)) {
                dev_err(cs->dev, "%s: message parser failure\n", __func__);
                dev_kfree_skb_any(skb);
                return;
        }
        dump_cmsg(DEBUG_CMD, __func__, cmsg);

        /* extract and check channel number from PLCI */
        channel = (cmsg->adr.adrPLCI >> 8) & 0xff;
        if (!channel || channel > cs->channels) {
                dev_notice(cs->dev, "%s: invalid %s 0x%02x\n",
                           "CONNECT_B3_REQ", "PLCI", cmsg->adr.adrPLCI);
                send_conf(iif, ap, skb, CapiIllContrPlciNcci);
                return;
        }
        bcs = &cs->bcs[channel - 1];

        /* mark logical connection active */
        bcs->apconnstate = APCONN_ACTIVE;

        /* build NCCI: always 1 (one B3 connection only) */
        cmsg->adr.adrNCCI |= 1 << 16;

        /* NCPI parameter: not applicable for B3 Transparent */
        ignore_cstruct_param(cs, cmsg->NCPI, "CONNECT_B3_REQ", "NCPI");
        send_conf(iif, ap, skb,
                  (cmsg->NCPI && cmsg->NCPI[0]) ?
                  CapiNcpiNotSupportedByProtocol : CapiSuccess);
}

/*
 * process CONNECT_B3_RESP message
 * Depending on the Reject parameter, either emit CONNECT_B3_ACTIVE_IND
 * or queue EV_HUP and emit DISCONNECT_B3_IND.
 * The emitted message is always shorter than the received one,
 * allowing to reuse the skb.
 */
static void do_connect_b3_resp(struct gigaset_capi_ctr *iif,
                               struct gigaset_capi_appl *ap,
                               struct sk_buff *skb)
{
        struct cardstate *cs = iif->ctr.driverdata;
        _cmsg *cmsg = &iif->acmsg;
        struct bc_state *bcs;
        int channel;
        unsigned int msgsize;
        u8 command;

        /* decode message */
        if (capi_message2cmsg(cmsg, skb->data)) {
                dev_err(cs->dev, "%s: message parser failure\n", __func__);
                dev_kfree_skb_any(skb);
                return;
        }
        dump_cmsg(DEBUG_CMD, __func__, cmsg);

        /* extract and check channel number and NCCI */
        channel = (cmsg->adr.adrNCCI >> 8) & 0xff;
        if (!channel || channel > cs->channels ||
            ((cmsg->adr.adrNCCI >> 16) & 0xffff) != 1) {
                dev_notice(cs->dev, "%s: invalid %s 0x%02x\n",
                           "CONNECT_B3_RESP", "NCCI", cmsg->adr.adrNCCI);
                dev_kfree_skb_any(skb);
                return;
        }
        bcs = &cs->bcs[channel - 1];

        if (cmsg->Reject) {
                /* Reject: clear B3 connect received flag */
                bcs->apconnstate = APCONN_SETUP;

                /* trigger hangup, causing eventual DISCONNECT_IND */
                if (!gigaset_add_event(cs, &bcs->at_state,
                                       EV_HUP, NULL, 0, NULL)) {
                        dev_kfree_skb_any(skb);
                        return;
                }
                gigaset_schedule_event(cs);

                /* emit DISCONNECT_B3_IND */
                command = CAPI_DISCONNECT_B3;
                msgsize = CAPI_DISCONNECT_B3_IND_BASELEN;
        } else {
                /*
                 * Accept: emit CONNECT_B3_ACTIVE_IND immediately, as
                 * we only send CONNECT_B3_IND if the B channel is up
                 */
                command = CAPI_CONNECT_B3_ACTIVE;
                msgsize = CAPI_CONNECT_B3_ACTIVE_IND_BASELEN;
        }
        capi_cmsg_header(cmsg, ap->id, command, CAPI_IND,
                         ap->nextMessageNumber++, cmsg->adr.adrNCCI);
        __skb_trim(skb, msgsize);
        if (capi_cmsg2message(cmsg, skb->data)) {
                dev_err(cs->dev, "%s: message parser failure\n", __func__);
                dev_kfree_skb_any(skb);
                return;
        }
        dump_cmsg(DEBUG_CMD, __func__, cmsg);
        capi_ctr_handle_message(&iif->ctr, ap->id, skb);
}

/*
 * process DISCONNECT_REQ message
 * schedule EV_HUP and emit DISCONNECT_B3_IND if necessary,
 * emit DISCONNECT_CONF reply
 */
static void do_disconnect_req(struct gigaset_capi_ctr *iif,
                              struct gigaset_capi_appl *ap,
                              struct sk_buff *skb)
{
        struct cardstate *cs = iif->ctr.driverdata;
        _cmsg *cmsg = &iif->acmsg;
        struct bc_state *bcs;
        _cmsg *b3cmsg;
        struct sk_buff *b3skb;
        int channel;

        /* decode message */
        if (capi_message2cmsg(cmsg, skb->data)) {
                dev_err(cs->dev, "%s: message parser failure\n", __func__);
                dev_kfree_skb_any(skb);
                return;
        }
        dump_cmsg(DEBUG_CMD, __func__, cmsg);

        /* extract and check channel number from PLCI */
        channel = (cmsg->adr.adrPLCI >> 8) & 0xff;
        if (!channel || channel > cs->channels) {
                dev_notice(cs->dev, "%s: invalid %s 0x%02x\n",
                           "DISCONNECT_REQ", "PLCI", cmsg->adr.adrPLCI);
                send_conf(iif, ap, skb, CapiIllContrPlciNcci);
                return;
        }
        bcs = cs->bcs + channel - 1;

        /* ToDo: process parameter: Additional info */
        if (cmsg->AdditionalInfo != CAPI_DEFAULT) {
                ignore_cstruct_param(cs, cmsg->BChannelinformation,
                                     "DISCONNECT_REQ", "B Channel Information");
                ignore_cstruct_param(cs, cmsg->Keypadfacility,
                                     "DISCONNECT_REQ", "Keypad Facility");
                ignore_cstruct_param(cs, cmsg->Useruserdata,
                                     "DISCONNECT_REQ", "User-User Data");
                ignore_cstruct_param(cs, cmsg->Facilitydataarray,
                                     "DISCONNECT_REQ", "Facility Data Array");
        }

        /* skip if DISCONNECT_IND already sent */
        if (!bcs->apconnstate)
                return;

        /* check for active logical connection */
        if (bcs->apconnstate >= APCONN_ACTIVE) {
                /* clear it */
                bcs->apconnstate = APCONN_SETUP;

                /*
                 * emit DISCONNECT_B3_IND with cause 0x3301
                 * use separate cmsg structure, as the content of iif->acmsg
                 * is still needed for creating the _CONF message
                 */
                b3cmsg = kmalloc(sizeof(*b3cmsg), GFP_KERNEL);
                if (!b3cmsg) {
                        dev_err(cs->dev, "%s: out of memory\n", __func__);
                        send_conf(iif, ap, skb, CAPI_MSGOSRESOURCEERR);
                        return;
                }
                capi_cmsg_header(b3cmsg, ap->id, CAPI_DISCONNECT_B3, CAPI_IND,
                                 ap->nextMessageNumber++,
                                 cmsg->adr.adrPLCI | (1 << 16));
                b3cmsg->Reason_B3 = CapiProtocolErrorLayer1;
                b3skb = alloc_skb(CAPI_DISCONNECT_B3_IND_BASELEN, GFP_KERNEL);
                if (b3skb == NULL) {
                        dev_err(cs->dev, "%s: out of memory\n", __func__);
                        send_conf(iif, ap, skb, CAPI_MSGOSRESOURCEERR);
                        kfree(b3cmsg);
                        return;
                }
                if (capi_cmsg2message(b3cmsg,
                                      __skb_put(b3skb, CAPI_DISCONNECT_B3_IND_BASELEN))) {
                        dev_err(cs->dev, "%s: message parser failure\n",
                                __func__);
                        kfree(b3cmsg);
                        dev_kfree_skb_any(b3skb);
                        return;
                }
                dump_cmsg(DEBUG_CMD, __func__, b3cmsg);
                kfree(b3cmsg);
                capi_ctr_handle_message(&iif->ctr, ap->id, b3skb);
        }

        /* trigger hangup, causing eventual DISCONNECT_IND */
        if (!gigaset_add_event(cs, &bcs->at_state, EV_HUP, NULL, 0, NULL)) {
                send_conf(iif, ap, skb, CAPI_MSGOSRESOURCEERR);
                return;
        }

        gigaset_schedule_event(cs);

        /* emit reply */
        send_conf(iif, ap, skb, CapiSuccess);
}

/*
 * process DISCONNECT_B3_REQ message
 * schedule EV_HUP and emit DISCONNECT_B3_CONF reply
 */
static void do_disconnect_b3_req(struct gigaset_capi_ctr *iif,
                                 struct gigaset_capi_appl *ap,
                                 struct sk_buff *skb)
{
        struct cardstate *cs = iif->ctr.driverdata;
        _cmsg *cmsg = &iif->acmsg;
        struct bc_state *bcs;
        int channel;

        /* decode message */
        if (capi_message2cmsg(cmsg, skb->data)) {
                dev_err(cs->dev, "%s: message parser failure\n", __func__);
                dev_kfree_skb_any(skb);
                return;
        }
        dump_cmsg(DEBUG_CMD, __func__, cmsg);

        /* extract and check channel number and NCCI */
        channel = (cmsg->adr.adrNCCI >> 8) & 0xff;
        if (!channel || channel > cs->channels ||
            ((cmsg->adr.adrNCCI >> 16) & 0xffff) != 1) {
                dev_notice(cs->dev, "%s: invalid %s 0x%02x\n",
                           "DISCONNECT_B3_REQ", "NCCI", cmsg->adr.adrNCCI);
                send_conf(iif, ap, skb, CapiIllContrPlciNcci);
                return;
        }
        bcs = &cs->bcs[channel - 1];

        /* reject if logical connection not active */
        if (bcs->apconnstate < APCONN_ACTIVE) {
                send_conf(iif, ap, skb,
                          CapiMessageNotSupportedInCurrentState);
                return;
        }

        /* trigger hangup, causing eventual DISCONNECT_B3_IND */
        if (!gigaset_add_event(cs, &bcs->at_state, EV_HUP, NULL, 0, NULL)) {
                send_conf(iif, ap, skb, CAPI_MSGOSRESOURCEERR);
                return;
        }
        gigaset_schedule_event(cs);

        /* NCPI parameter: not applicable for B3 Transparent */
        ignore_cstruct_param(cs, cmsg->NCPI,
                             "DISCONNECT_B3_REQ", "NCPI");
        send_conf(iif, ap, skb,
                  (cmsg->NCPI && cmsg->NCPI[0]) ?
                  CapiNcpiNotSupportedByProtocol : CapiSuccess);
}

/*
 * process DATA_B3_REQ message
 */
static void do_data_b3_req(struct gigaset_capi_ctr *iif,
                           struct gigaset_capi_appl *ap,
                           struct sk_buff *skb)
{
        struct cardstate *cs = iif->ctr.driverdata;
        struct bc_state *bcs;
        int channel = CAPIMSG_PLCI_PART(skb->data);
        u16 ncci = CAPIMSG_NCCI_PART(skb->data);
        u16 msglen = CAPIMSG_LEN(skb->data);
        u16 datalen = CAPIMSG_DATALEN(skb->data);
        u16 flags = CAPIMSG_FLAGS(skb->data);
        u16 msgid = CAPIMSG_MSGID(skb->data);
        u16 handle = CAPIMSG_HANDLE_REQ(skb->data);

        /* frequent message, avoid _cmsg overhead */
        dump_rawmsg(DEBUG_MCMD, __func__, skb->data);

        /* check parameters */
        if (channel == 0 || channel > cs->channels || ncci != 1) {
                dev_notice(cs->dev, "%s: invalid %s 0x%02x\n",
                           "DATA_B3_REQ", "NCCI", CAPIMSG_NCCI(skb->data));
                send_conf(iif, ap, skb, CapiIllContrPlciNcci);
                return;
        }
        bcs = &cs->bcs[channel - 1];
        if (msglen != CAPI_DATA_B3_REQ_LEN && msglen != CAPI_DATA_B3_REQ_LEN64)
                dev_notice(cs->dev, "%s: unexpected length %d\n",
                           "DATA_B3_REQ", msglen);
        if (msglen + datalen != skb->len)
                dev_notice(cs->dev, "%s: length mismatch (%d+%d!=%d)\n",
                           "DATA_B3_REQ", msglen, datalen, skb->len);
        if (msglen + datalen > skb->len) {
                /* message too short for announced data length */
                send_conf(iif, ap, skb, CapiIllMessageParmCoding); /* ? */
                return;
        }
        if (flags & CAPI_FLAGS_RESERVED) {
                dev_notice(cs->dev, "%s: reserved flags set (%x)\n",
                           "DATA_B3_REQ", flags);
                send_conf(iif, ap, skb, CapiIllMessageParmCoding);
                return;
        }

        /* reject if logical connection not active */
        if (bcs->apconnstate < APCONN_ACTIVE) {
                send_conf(iif, ap, skb, CapiMessageNotSupportedInCurrentState);
                return;
        }

        /* pull CAPI message into link layer header */
        skb_reset_mac_header(skb);
        skb->mac_len = msglen;
        skb_pull(skb, msglen);

        /* pass to device-specific module */
        if (cs->ops->send_skb(bcs, skb) < 0) {
                send_conf(iif, ap, skb, CAPI_MSGOSRESOURCEERR);
                return;
        }

        /*
         * DATA_B3_CONF will be sent by gigaset_skb_sent() only if "delivery
         * confirmation" bit is set; otherwise we have to send it now
         */
        if (!(flags & CAPI_FLAGS_DELIVERY_CONFIRMATION))
                send_data_b3_conf(cs, &iif->ctr, ap->id, msgid, channel, handle,
                                  flags ? CapiFlagsNotSupportedByProtocol
                                  : CAPI_NOERROR);
}

/*
 * process RESET_B3_REQ message
 * just always reply "not supported by current protocol"
 */
static void do_reset_b3_req(struct gigaset_capi_ctr *iif,
                            struct gigaset_capi_appl *ap,
                            struct sk_buff *skb)
{
        struct cardstate *cs = iif->ctr.driverdata;

        /* decode message */
        if (capi_message2cmsg(&iif->acmsg, skb->data)) {
                dev_err(cs->dev, "%s: message parser failure\n", __func__);
                dev_kfree_skb_any(skb);
                return;
        }
        dump_cmsg(DEBUG_CMD, __func__, &iif->acmsg);
        send_conf(iif, ap, skb,
                  CapiResetProcedureNotSupportedByCurrentProtocol);
}

/*
 * unsupported CAPI message handler
 */
static void do_unsupported(struct gigaset_capi_ctr *iif,
                           struct gigaset_capi_appl *ap,
                           struct sk_buff *skb)
{
        struct cardstate *cs = iif->ctr.driverdata;

        /* decode message */
        if (capi_message2cmsg(&iif->acmsg, skb->data)) {
                dev_err(cs->dev, "%s: message parser failure\n", __func__);
                dev_kfree_skb_any(skb);
                return;
        }
        dump_cmsg(DEBUG_CMD, __func__, &iif->acmsg);
        send_conf(iif, ap, skb, CapiMessageNotSupportedInCurrentState);
}

/*
 * CAPI message handler: no-op
 */
static void do_nothing(struct gigaset_capi_ctr *iif,
                       struct gigaset_capi_appl *ap,
                       struct sk_buff *skb)
{
        struct cardstate *cs = iif->ctr.driverdata;

        /* decode message */
        if (capi_message2cmsg(&iif->acmsg, skb->data)) {
                dev_err(cs->dev, "%s: message parser failure\n", __func__);
                dev_kfree_skb_any(skb);
                return;
        }
        dump_cmsg(DEBUG_CMD, __func__, &iif->acmsg);
        dev_kfree_skb_any(skb);
}

static void do_data_b3_resp(struct gigaset_capi_ctr *iif,
                            struct gigaset_capi_appl *ap,
                            struct sk_buff *skb)
{
        dump_rawmsg(DEBUG_MCMD, __func__, skb->data);
        dev_kfree_skb_any(skb);
}

/* table of outgoing CAPI message handlers with lookup function */
typedef void (*capi_send_handler_t)(struct gigaset_capi_ctr *,
                                    struct gigaset_capi_appl *,
                                    struct sk_buff *);

static struct {
        u16 cmd;
        capi_send_handler_t handler;
} capi_send_handler_table[] = {
        /* most frequent messages first for faster lookup */
        { CAPI_DATA_B3_REQ, do_data_b3_req },
        { CAPI_DATA_B3_RESP, do_data_b3_resp },

        { CAPI_ALERT_REQ, do_alert_req },
        { CAPI_CONNECT_ACTIVE_RESP, do_nothing },
        { CAPI_CONNECT_B3_ACTIVE_RESP, do_nothing },
        { CAPI_CONNECT_B3_REQ, do_connect_b3_req },
        { CAPI_CONNECT_B3_RESP, do_connect_b3_resp },
        { CAPI_CONNECT_B3_T90_ACTIVE_RESP, do_nothing },
        { CAPI_CONNECT_REQ, do_connect_req },
        { CAPI_CONNECT_RESP, do_connect_resp },
        { CAPI_DISCONNECT_B3_REQ, do_disconnect_b3_req },
        { CAPI_DISCONNECT_B3_RESP, do_nothing },
        { CAPI_DISCONNECT_REQ, do_disconnect_req },
        { CAPI_DISCONNECT_RESP, do_nothing },
        { CAPI_FACILITY_REQ, do_facility_req },
        { CAPI_FACILITY_RESP, do_nothing },
        { CAPI_LISTEN_REQ, do_listen_req },
        { CAPI_SELECT_B_PROTOCOL_REQ, do_unsupported },
        { CAPI_RESET_B3_REQ, do_reset_b3_req },
        { CAPI_RESET_B3_RESP, do_nothing },

        /*
         * ToDo: support overlap sending (requires ev-layer state
         * machine extension to generate additional ATD commands)
         */
        { CAPI_INFO_REQ, do_unsupported },
        { CAPI_INFO_RESP, do_nothing },

        /*
         * ToDo: what's the proper response for these?
         */
        { CAPI_MANUFACTURER_REQ, do_nothing },
        { CAPI_MANUFACTURER_RESP, do_nothing },
};

/* look up handler */
static inline capi_send_handler_t lookup_capi_send_handler(const u16 cmd)
{
        size_t i;

        for (i = 0; i < ARRAY_SIZE(capi_send_handler_table); i++)
                if (capi_send_handler_table[i].cmd == cmd)
                        return capi_send_handler_table[i].handler;
        return NULL;
}


/**
 * gigaset_send_message() - accept a CAPI message from an application
 * @ctr:        controller descriptor structure.
 * @skb:        CAPI message.
 *
 * Return value: CAPI error code
 * Note: capidrv (and probably others, too) only uses the return value to
 * decide whether it has to free the skb (only if result != CAPI_NOERROR (0))
 */
static u16 gigaset_send_message(struct capi_ctr *ctr, struct sk_buff *skb)
{
        struct gigaset_capi_ctr *iif
                = container_of(ctr, struct gigaset_capi_ctr, ctr);
        struct cardstate *cs = ctr->driverdata;
        struct gigaset_capi_appl *ap;
        capi_send_handler_t handler;

        /* can only handle linear sk_buffs */
        if (skb_linearize(skb) < 0) {
                dev_warn(cs->dev, "%s: skb_linearize failed\n", __func__);
                return CAPI_MSGOSRESOURCEERR;
        }

        /* retrieve application data structure */
        ap = get_appl(iif, CAPIMSG_APPID(skb->data));
        if (!ap) {
                dev_notice(cs->dev, "%s: application %u not registered\n",
                           __func__, CAPIMSG_APPID(skb->data));
                return CAPI_ILLAPPNR;
        }

        /* look up command */
        handler = lookup_capi_send_handler(CAPIMSG_CMD(skb->data));
        if (!handler) {
                /* unknown/unsupported message type */
                if (printk_ratelimit())
                        dev_notice(cs->dev, "%s: unsupported message %u\n",
                                   __func__, CAPIMSG_CMD(skb->data));
                return CAPI_ILLCMDORSUBCMDORMSGTOSMALL;
        }

        /* serialize */
        if (atomic_add_return(1, &iif->sendqlen) > 1) {
                /* queue behind other messages */
                skb_queue_tail(&iif->sendqueue, skb);
                return CAPI_NOERROR;
        }

        /* process message */
        handler(iif, ap, skb);

        /* process other messages arrived in the meantime */
        while (atomic_sub_return(1, &iif->sendqlen) > 0) {
                skb = skb_dequeue(&iif->sendqueue);
                if (!skb) {
                        /* should never happen */
                        dev_err(cs->dev, "%s: send queue empty\n", __func__);
                        continue;
                }
                ap = get_appl(iif, CAPIMSG_APPID(skb->data));
                if (!ap) {
                        /* could that happen? */
                        dev_warn(cs->dev, "%s: application %u vanished\n",
                                 __func__, CAPIMSG_APPID(skb->data));
                        continue;
                }
                handler = lookup_capi_send_handler(CAPIMSG_CMD(skb->data));
                if (!handler) {
                        /* should never happen */
                        dev_err(cs->dev, "%s: handler %x vanished\n",
                                __func__, CAPIMSG_CMD(skb->data));
                        continue;
                }
                handler(iif, ap, skb);
        }

        return CAPI_NOERROR;
}

/**
 * gigaset_procinfo() - build single line description for controller
 * @ctr:        controller descriptor structure.
 *
 * Return value: pointer to generated string (null terminated)
 */
static char *gigaset_procinfo(struct capi_ctr *ctr)
{
        return ctr->name;       /* ToDo: more? */
}

static int gigaset_proc_show(struct seq_file *m, void *v)
{
        struct capi_ctr *ctr = m->private;
        struct cardstate *cs = ctr->driverdata;
        char *s;
        int i;

        seq_printf(m, "%-16s %s\n", "name", ctr->name);
        seq_printf(m, "%-16s %s %s\n", "dev",
                   dev_driver_string(cs->dev), dev_name(cs->dev));
        seq_printf(m, "%-16s %d\n", "id", cs->myid);
        if (cs->gotfwver)
                seq_printf(m, "%-16s %d.%d.%d.%d\n", "firmware",
                           cs->fwver[0], cs->fwver[1], cs->fwver[2], cs->fwver[3]);
        seq_printf(m, "%-16s %d\n", "channels", cs->channels);
        seq_printf(m, "%-16s %s\n", "onechannel", cs->onechannel ? "yes" : "no");

        switch (cs->mode) {
        case M_UNKNOWN:
                s = "unknown";
                break;
        case M_CONFIG:
                s = "config";
                break;
        case M_UNIMODEM:
                s = "Unimodem";
                break;
        case M_CID:
                s = "CID";
                break;
        default:
                s = "??";
        }
        seq_printf(m, "%-16s %s\n", "mode", s);

        switch (cs->mstate) {
        case MS_UNINITIALIZED:
                s = "uninitialized";
                break;
        case MS_INIT:
                s = "init";
                break;
        case MS_LOCKED:
                s = "locked";
                break;
        case MS_SHUTDOWN:
                s = "shutdown";
                break;
        case MS_RECOVER:
                s = "recover";
                break;
        case MS_READY:
                s = "ready";
                break;
        default:
                s = "??";
        }
        seq_printf(m, "%-16s %s\n", "mstate", s);

        seq_printf(m, "%-16s %s\n", "running", cs->running ? "yes" : "no");
        seq_printf(m, "%-16s %s\n", "connected", cs->connected ? "yes" : "no");
        seq_printf(m, "%-16s %s\n", "isdn_up", cs->isdn_up ? "yes" : "no");
        seq_printf(m, "%-16s %s\n", "cidmode", cs->cidmode ? "yes" : "no");

        for (i = 0; i < cs->channels; i++) {
                seq_printf(m, "[%d]%-13s %d\n", i, "corrupted",
                           cs->bcs[i].corrupted);
                seq_printf(m, "[%d]%-13s %d\n", i, "trans_down",
                           cs->bcs[i].trans_down);
                seq_printf(m, "[%d]%-13s %d\n", i, "trans_up",
                           cs->bcs[i].trans_up);
                seq_printf(m, "[%d]%-13s %d\n", i, "chstate",
                           cs->bcs[i].chstate);
                switch (cs->bcs[i].proto2) {
                case L2_BITSYNC:
                        s = "bitsync";
                        break;
                case L2_HDLC:
                        s = "HDLC";
                        break;
                case L2_VOICE:
                        s = "voice";
                        break;
                default:
                        s = "??";
                }
                seq_printf(m, "[%d]%-13s %s\n", i, "proto2", s);
        }
        return 0;
}

static int gigaset_proc_open(struct inode *inode, struct file *file)
{
        return single_open(file, gigaset_proc_show, PDE_DATA(inode));
}

static const struct file_operations gigaset_proc_fops = {
        .owner          = THIS_MODULE,
        .open           = gigaset_proc_open,
        .read           = seq_read,
        .llseek         = seq_lseek,
        .release        = single_release,
};

/**
 * gigaset_isdn_regdev() - register device to LL
 * @cs:         device descriptor structure.
 * @isdnid:     device name.
 *
 * Return value: 0 on success, error code < 0 on failure
 */
int gigaset_isdn_regdev(struct cardstate *cs, const char *isdnid)
{
        struct gigaset_capi_ctr *iif;
        int rc;

        iif = kzalloc(sizeof(*iif), GFP_KERNEL);
        if (!iif) {
                pr_err("%s: out of memory\n", __func__);
                return -ENOMEM;
        }

        /* prepare controller structure */
        iif->ctr.owner         = THIS_MODULE;
        iif->ctr.driverdata    = cs;
        strncpy(iif->ctr.name, isdnid, sizeof(iif->ctr.name) - 1);
        iif->ctr.driver_name   = "gigaset";
        iif->ctr.load_firmware = NULL;
        iif->ctr.reset_ctr     = NULL;
        iif->ctr.register_appl = gigaset_register_appl;
        iif->ctr.release_appl  = gigaset_release_appl;
        iif->ctr.send_message  = gigaset_send_message;
        iif->ctr.procinfo      = gigaset_procinfo;
        iif->ctr.proc_fops = &gigaset_proc_fops;
        INIT_LIST_HEAD(&iif->appls);
        skb_queue_head_init(&iif->sendqueue);
        atomic_set(&iif->sendqlen, 0);

        /* register controller with CAPI */
        rc = attach_capi_ctr(&iif->ctr);
        if (rc) {
                pr_err("attach_capi_ctr failed (%d)\n", rc);
                kfree(iif);
                return rc;
        }

        cs->iif = iif;
        cs->hw_hdr_len = CAPI_DATA_B3_REQ_LEN;
        return 0;
}

/**
 * gigaset_isdn_unregdev() - unregister device from LL
 * @cs:         device descriptor structure.
 */
void gigaset_isdn_unregdev(struct cardstate *cs)
{
        struct gigaset_capi_ctr *iif = cs->iif;

        detach_capi_ctr(&iif->ctr);
        kfree(iif);
        cs->iif = NULL;
}

static struct capi_driver capi_driver_gigaset = {
        .name           = "gigaset",
        .revision       = "1.0",
};

/**
 * gigaset_isdn_regdrv() - register driver to LL
 */
void gigaset_isdn_regdrv(void)
{
        pr_info("Kernel CAPI interface\n");
        register_capi_driver(&capi_driver_gigaset);
}

/**
 * gigaset_isdn_unregdrv() - unregister driver from LL
 */
void gigaset_isdn_unregdrv(void)
{
        unregister_capi_driver(&capi_driver_gigaset);
}