hdlc_fr.c

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/*
 * Generic HDLC support routines for Linux
 * Frame Relay support
 *
 * Copyright (C) 1999 - 2006 Krzysztof Halasa <[email protected]>
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms of version 2 of the GNU General Public License
 * as published by the Free Software Foundation.
 *

            Theory of PVC state

 DCE mode:

 (exist,new) -> 0,0 when "PVC create" or if "link unreliable"
         0,x -> 1,1 if "link reliable" when sending FULL STATUS
         1,1 -> 1,0 if received FULL STATUS ACK

 (active)    -> 0 when "ifconfig PVC down" or "link unreliable" or "PVC create"
             -> 1 when "PVC up" and (exist,new) = 1,0

 DTE mode:
 (exist,new,active) = FULL STATUS if "link reliable"
            = 0, 0, 0 if "link unreliable"
 No LMI:
 active = open and "link reliable"
 exist = new = not used

 CCITT LMI: ITU-T Q.933 Annex A
 ANSI LMI: ANSI T1.617 Annex D
 CISCO LMI: the original, aka "Gang of Four" LMI

*/

#include <linux/errno.h>
#include <linux/etherdevice.h>
#include <linux/hdlc.h>
#include <linux/if_arp.h>
#include <linux/inetdevice.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/pkt_sched.h>
#include <linux/poll.h>
#include <linux/rtnetlink.h>
#include <linux/skbuff.h>
#include <linux/slab.h>

#undef DEBUG_PKT
#undef DEBUG_ECN
#undef DEBUG_LINK
#undef DEBUG_PROTO
#undef DEBUG_PVC

#define FR_UI           0x03
#define FR_PAD          0x00

#define NLPID_IP        0xCC
#define NLPID_IPV6      0x8E
#define NLPID_SNAP      0x80
#define NLPID_PAD       0x00
#define NLPID_CCITT_ANSI_LMI    0x08
#define NLPID_CISCO_LMI     0x09


#define LMI_CCITT_ANSI_DLCI    0 /* LMI DLCI */
#define LMI_CISCO_DLCI      1023

#define LMI_CALLREF     0x00 /* Call Reference */
#define LMI_ANSI_LOCKSHIFT  0x95 /* ANSI locking shift */
#define LMI_ANSI_CISCO_REPTYPE  0x01 /* report type */
#define LMI_CCITT_REPTYPE   0x51
#define LMI_ANSI_CISCO_ALIVE    0x03 /* keep alive */
#define LMI_CCITT_ALIVE     0x53
#define LMI_ANSI_CISCO_PVCSTAT  0x07 /* PVC status */
#define LMI_CCITT_PVCSTAT   0x57

#define LMI_FULLREP     0x00 /* full report  */
#define LMI_INTEGRITY       0x01 /* link integrity report */
#define LMI_SINGLE      0x02 /* single PVC report */

#define LMI_STATUS_ENQUIRY      0x75
#define LMI_STATUS              0x7D /* reply */

#define LMI_REPT_LEN               1 /* report type element length */
#define LMI_INTEG_LEN              2 /* link integrity element length */

#define LMI_CCITT_CISCO_LENGTH    13 /* LMI frame lengths */
#define LMI_ANSI_LENGTH       14


typedef struct {
#if defined(__LITTLE_ENDIAN_BITFIELD)
    unsigned ea1:   1;
    unsigned cr:    1;
    unsigned dlcih: 6;

    unsigned ea2:   1;
    unsigned de:    1;
    unsigned becn:  1;
    unsigned fecn:  1;
    unsigned dlcil: 4;
#else
    unsigned dlcih: 6;
    unsigned cr:    1;
    unsigned ea1:   1;

    unsigned dlcil: 4;
    unsigned fecn:  1;
    unsigned becn:  1;
    unsigned de:    1;
    unsigned ea2:   1;
#endif
}__packed fr_hdr;


typedef struct pvc_device_struct {
    struct net_device *frad;
    struct net_device *main;
    struct net_device *ether;   /* bridged Ethernet interface   */
    struct pvc_device_struct *next; /* Sorted in ascending DLCI order */
    int dlci;
    int open_count;

    struct {
        unsigned int new: 1;
        unsigned int active: 1;
        unsigned int exist: 1;
        unsigned int deleted: 1;
        unsigned int fecn: 1;
        unsigned int becn: 1;
        unsigned int bandwidth; /* Cisco LMI reporting only */
    }state;
}pvc_device;

struct frad_state {
    fr_proto settings;
    pvc_device *first_pvc;
    int dce_pvc_count;

    struct timer_list timer;
    unsigned long last_poll;
    int reliable;
    int dce_changed;
    int request;
    int fullrep_sent;
    u32 last_errors; /* last errors bit list */
    u8 n391cnt;
    u8 txseq; /* TX sequence number */
    u8 rxseq; /* RX sequence number */
};


static int fr_ioctl(struct net_device *dev, struct ifreq *ifr);


static inline u16 q922_to_dlci(u8 *hdr)
{
    return ((hdr[0] & 0xFC) << 2) | ((hdr[1] & 0xF0) >> 4);
}


static inline void dlci_to_q922(u8 *hdr, u16 dlci)
{
    hdr[0] = (dlci >> 2) & 0xFC;
    hdr[1] = ((dlci << 4) & 0xF0) | 0x01;
}


static inline struct frad_state* state(hdlc_device *hdlc)
{
    return(struct frad_state *)(hdlc->state);
}


static inline pvc_device* find_pvc(hdlc_device *hdlc, u16 dlci)
{
    pvc_device *pvc = state(hdlc)->first_pvc;

    while (pvc) {
        if (pvc->dlci == dlci)
            return pvc;
        if (pvc->dlci > dlci)
            return NULL; /* the list is sorted */
        pvc = pvc->next;
    }

    return NULL;
}


static pvc_device* add_pvc(struct net_device *dev, u16 dlci)
{
    hdlc_device *hdlc = dev_to_hdlc(dev);
    pvc_device *pvc, **pvc_p = &state(hdlc)->first_pvc;

    while (*pvc_p) {
        if ((*pvc_p)->dlci == dlci)
            return *pvc_p;
        if ((*pvc_p)->dlci > dlci)
            break;  /* the list is sorted */
        pvc_p = &(*pvc_p)->next;
    }

    pvc = kzalloc(sizeof(pvc_device), GFP_ATOMIC);
#ifdef DEBUG_PVC
    printk(KERN_DEBUG "add_pvc: allocated pvc %p, frad %p\n", pvc, dev);
#endif
    if (!pvc)
        return NULL;

    pvc->dlci = dlci;
    pvc->frad = dev;
    pvc->next = *pvc_p; /* Put it in the chain */
    *pvc_p = pvc;
    return pvc;
}


static inline int pvc_is_used(pvc_device *pvc)
{
    return pvc->main || pvc->ether;
}


static inline void pvc_carrier(int on, pvc_device *pvc)
{
    if (on) {
        if (pvc->main)
            if (!netif_carrier_ok(pvc->main))
                netif_carrier_on(pvc->main);
        if (pvc->ether)
            if (!netif_carrier_ok(pvc->ether))
                netif_carrier_on(pvc->ether);
    } else {
        if (pvc->main)
            if (netif_carrier_ok(pvc->main))
                netif_carrier_off(pvc->main);
        if (pvc->ether)
            if (netif_carrier_ok(pvc->ether))
                netif_carrier_off(pvc->ether);
    }
}


static inline void delete_unused_pvcs(hdlc_device *hdlc)
{
    pvc_device **pvc_p = &state(hdlc)->first_pvc;

    while (*pvc_p) {
        if (!pvc_is_used(*pvc_p)) {
            pvc_device *pvc = *pvc_p;
#ifdef DEBUG_PVC
            printk(KERN_DEBUG "freeing unused pvc: %p\n", pvc);
#endif
            *pvc_p = pvc->next;
            kfree(pvc);
            continue;
        }
        pvc_p = &(*pvc_p)->next;
    }
}


static inline struct net_device** get_dev_p(pvc_device *pvc, int type)
{
    if (type == ARPHRD_ETHER)
        return &pvc->ether;
    else
        return &pvc->main;
}


static int fr_hard_header(struct sk_buff **skb_p, u16 dlci)
{
    u16 head_len;
    struct sk_buff *skb = *skb_p;

    switch (skb->protocol) {
    case cpu_to_be16(NLPID_CCITT_ANSI_LMI):
        head_len = 4;
        skb_push(skb, head_len);
        skb->data[3] = NLPID_CCITT_ANSI_LMI;
        break;

    case cpu_to_be16(NLPID_CISCO_LMI):
        head_len = 4;
        skb_push(skb, head_len);
        skb->data[3] = NLPID_CISCO_LMI;
        break;

    case cpu_to_be16(ETH_P_IP):
        head_len = 4;
        skb_push(skb, head_len);
        skb->data[3] = NLPID_IP;
        break;

    case cpu_to_be16(ETH_P_IPV6):
        head_len = 4;
        skb_push(skb, head_len);
        skb->data[3] = NLPID_IPV6;
        break;

    case cpu_to_be16(ETH_P_802_3):
        head_len = 10;
        if (skb_headroom(skb) < head_len) {
            struct sk_buff *skb2 = skb_realloc_headroom(skb,
                                    head_len);
            if (!skb2)
                return -ENOBUFS;
            dev_kfree_skb(skb);
            skb = *skb_p = skb2;
        }
        skb_push(skb, head_len);
        skb->data[3] = FR_PAD;
        skb->data[4] = NLPID_SNAP;
        skb->data[5] = FR_PAD;
        skb->data[6] = 0x80;
        skb->data[7] = 0xC2;
        skb->data[8] = 0x00;
        skb->data[9] = 0x07; /* bridged Ethernet frame w/out FCS */
        break;

    default:
        head_len = 10;
        skb_push(skb, head_len);
        skb->data[3] = FR_PAD;
        skb->data[4] = NLPID_SNAP;
        skb->data[5] = FR_PAD;
        skb->data[6] = FR_PAD;
        skb->data[7] = FR_PAD;
        *(__be16*)(skb->data + 8) = skb->protocol;
    }

    dlci_to_q922(skb->data, dlci);
    skb->data[2] = FR_UI;
    return 0;
}



static int pvc_open(struct net_device *dev)
{
    pvc_device *pvc = dev->ml_priv;

    if ((pvc->frad->flags & IFF_UP) == 0)
        return -EIO;  /* Frad must be UP in order to activate PVC */

    if (pvc->open_count++ == 0) {
        hdlc_device *hdlc = dev_to_hdlc(pvc->frad);
        if (state(hdlc)->settings.lmi == LMI_NONE)
            pvc->state.active = netif_carrier_ok(pvc->frad);

        pvc_carrier(pvc->state.active, pvc);
        state(hdlc)->dce_changed = 1;
    }
    return 0;
}



static int pvc_close(struct net_device *dev)
{
    pvc_device *pvc = dev->ml_priv;

    if (--pvc->open_count == 0) {
        hdlc_device *hdlc = dev_to_hdlc(pvc->frad);
        if (state(hdlc)->settings.lmi == LMI_NONE)
            pvc->state.active = 0;

        if (state(hdlc)->settings.dce) {
            state(hdlc)->dce_changed = 1;
            pvc->state.active = 0;
        }
    }
    return 0;
}



static int pvc_ioctl(struct net_device *dev, struct ifreq *ifr, int cmd)
{
    pvc_device *pvc = dev->ml_priv;
    fr_proto_pvc_info info;

    if (ifr->ifr_settings.type == IF_GET_PROTO) {
        if (dev->type == ARPHRD_ETHER)
            ifr->ifr_settings.type = IF_PROTO_FR_ETH_PVC;
        else
            ifr->ifr_settings.type = IF_PROTO_FR_PVC;

        if (ifr->ifr_settings.size < sizeof(info)) {
            /* data size wanted */
            ifr->ifr_settings.size = sizeof(info);
            return -ENOBUFS;
        }

        info.dlci = pvc->dlci;
        memcpy(info.master, pvc->frad->name, IFNAMSIZ);
        if (copy_to_user(ifr->ifr_settings.ifs_ifsu.fr_pvc_info,
                 &info, sizeof(info)))
            return -EFAULT;
        return 0;
    }

    return -EINVAL;
}

static netdev_tx_t pvc_xmit(struct sk_buff *skb, struct net_device *dev)
{
    pvc_device *pvc = dev->ml_priv;

    if (pvc->state.active) {
        if (dev->type == ARPHRD_ETHER) {
            int pad = ETH_ZLEN - skb->len;
            if (pad > 0) { /* Pad the frame with zeros */
                int len = skb->len;
                if (skb_tailroom(skb) < pad)
                    if (pskb_expand_head(skb, 0, pad,
                                 GFP_ATOMIC)) {
                        dev->stats.tx_dropped++;
                        dev_kfree_skb(skb);
                        return NETDEV_TX_OK;
                    }
                skb_put(skb, pad);
                memset(skb->data + len, 0, pad);
            }
            skb->protocol = cpu_to_be16(ETH_P_802_3);
        }
        if (!fr_hard_header(&skb, pvc->dlci)) {
            dev->stats.tx_bytes += skb->len;
            dev->stats.tx_packets++;
            if (pvc->state.fecn) /* TX Congestion counter */
                dev->stats.tx_compressed++;
            skb->dev = pvc->frad;
            dev_queue_xmit(skb);
            return NETDEV_TX_OK;
        }
    }

    dev->stats.tx_dropped++;
    dev_kfree_skb(skb);
    return NETDEV_TX_OK;
}

static inline void fr_log_dlci_active(pvc_device *pvc)
{
    netdev_info(pvc->frad, "DLCI %d [%s%s%s]%s %s\n",
            pvc->dlci,
            pvc->main ? pvc->main->name : "",
            pvc->main && pvc->ether ? " " : "",
            pvc->ether ? pvc->ether->name : "",
            pvc->state.new ? " new" : "",
            !pvc->state.exist ? "deleted" :
            pvc->state.active ? "active" : "inactive");
}



static inline u8 fr_lmi_nextseq(u8 x)
{
    x++;
    return x ? x : 1;
}


static void fr_lmi_send(struct net_device *dev, int fullrep)
{
    hdlc_device *hdlc = dev_to_hdlc(dev);
    struct sk_buff *skb;
    pvc_device *pvc = state(hdlc)->first_pvc;
    int lmi = state(hdlc)->settings.lmi;
    int dce = state(hdlc)->settings.dce;
    int len = lmi == LMI_ANSI ? LMI_ANSI_LENGTH : LMI_CCITT_CISCO_LENGTH;
    int stat_len = (lmi == LMI_CISCO) ? 6 : 3;
    u8 *data;
    int i = 0;

    if (dce && fullrep) {
        len += state(hdlc)->dce_pvc_count * (2 + stat_len);
        if (len > HDLC_MAX_MRU) {
            netdev_warn(dev, "Too many PVCs while sending LMI full report\n");
            return;
        }
    }

    skb = dev_alloc_skb(len);
    if (!skb) {
        netdev_warn(dev, "Memory squeeze on fr_lmi_send()\n");
        return;
    }
    memset(skb->data, 0, len);
    skb_reserve(skb, 4);
    if (lmi == LMI_CISCO) {
        skb->protocol = cpu_to_be16(NLPID_CISCO_LMI);
        fr_hard_header(&skb, LMI_CISCO_DLCI);
    } else {
        skb->protocol = cpu_to_be16(NLPID_CCITT_ANSI_LMI);
        fr_hard_header(&skb, LMI_CCITT_ANSI_DLCI);
    }
    data = skb_tail_pointer(skb);
    data[i++] = LMI_CALLREF;
    data[i++] = dce ? LMI_STATUS : LMI_STATUS_ENQUIRY;
    if (lmi == LMI_ANSI)
        data[i++] = LMI_ANSI_LOCKSHIFT;
    data[i++] = lmi == LMI_CCITT ? LMI_CCITT_REPTYPE :
        LMI_ANSI_CISCO_REPTYPE;
    data[i++] = LMI_REPT_LEN;
    data[i++] = fullrep ? LMI_FULLREP : LMI_INTEGRITY;
    data[i++] = lmi == LMI_CCITT ? LMI_CCITT_ALIVE : LMI_ANSI_CISCO_ALIVE;
    data[i++] = LMI_INTEG_LEN;
    data[i++] = state(hdlc)->txseq =
        fr_lmi_nextseq(state(hdlc)->txseq);
    data[i++] = state(hdlc)->rxseq;

    if (dce && fullrep) {
        while (pvc) {
            data[i++] = lmi == LMI_CCITT ? LMI_CCITT_PVCSTAT :
                LMI_ANSI_CISCO_PVCSTAT;
            data[i++] = stat_len;

            /* LMI start/restart */
            if (state(hdlc)->reliable && !pvc->state.exist) {
                pvc->state.exist = pvc->state.new = 1;
                fr_log_dlci_active(pvc);
            }

            /* ifconfig PVC up */
            if (pvc->open_count && !pvc->state.active &&
                pvc->state.exist && !pvc->state.new) {
                pvc_carrier(1, pvc);
                pvc->state.active = 1;
                fr_log_dlci_active(pvc);
            }

            if (lmi == LMI_CISCO) {
                data[i] = pvc->dlci >> 8;
                data[i + 1] = pvc->dlci & 0xFF;
            } else {
                data[i] = (pvc->dlci >> 4) & 0x3F;
                data[i + 1] = ((pvc->dlci << 3) & 0x78) | 0x80;
                data[i + 2] = 0x80;
            }

            if (pvc->state.new)
                data[i + 2] |= 0x08;
            else if (pvc->state.active)
                data[i + 2] |= 0x02;

            i += stat_len;
            pvc = pvc->next;
        }
    }

    skb_put(skb, i);
    skb->priority = TC_PRIO_CONTROL;
    skb->dev = dev;
    skb_reset_network_header(skb);

    dev_queue_xmit(skb);
}



static void fr_set_link_state(int reliable, struct net_device *dev)
{
    hdlc_device *hdlc = dev_to_hdlc(dev);
    pvc_device *pvc = state(hdlc)->first_pvc;

    state(hdlc)->reliable = reliable;
    if (reliable) {
        netif_dormant_off(dev);
        state(hdlc)->n391cnt = 0; /* Request full status */
        state(hdlc)->dce_changed = 1;

        if (state(hdlc)->settings.lmi == LMI_NONE) {
            while (pvc) {   /* Activate all PVCs */
                pvc_carrier(1, pvc);
                pvc->state.exist = pvc->state.active = 1;
                pvc->state.new = 0;
                pvc = pvc->next;
            }
        }
    } else {
        netif_dormant_on(dev);
        while (pvc) {       /* Deactivate all PVCs */
            pvc_carrier(0, pvc);
            pvc->state.exist = pvc->state.active = 0;
            pvc->state.new = 0;
            if (!state(hdlc)->settings.dce)
                pvc->state.bandwidth = 0;
            pvc = pvc->next;
        }
    }
}


static void fr_timer(unsigned long arg)
{
    struct net_device *dev = (struct net_device *)arg;
    hdlc_device *hdlc = dev_to_hdlc(dev);
    int i, cnt = 0, reliable;
    u32 list;

    if (state(hdlc)->settings.dce) {
        reliable = state(hdlc)->request &&
            time_before(jiffies, state(hdlc)->last_poll +
                    state(hdlc)->settings.t392 * HZ);
        state(hdlc)->request = 0;
    } else {
        state(hdlc)->last_errors <<= 1; /* Shift the list */
        if (state(hdlc)->request) {
            if (state(hdlc)->reliable)
                netdev_info(dev, "No LMI status reply received\n");
            state(hdlc)->last_errors |= 1;
        }

        list = state(hdlc)->last_errors;
        for (i = 0; i < state(hdlc)->settings.n393; i++, list >>= 1)
            cnt += (list & 1);  /* errors count */

        reliable = (cnt < state(hdlc)->settings.n392);
    }

    if (state(hdlc)->reliable != reliable) {
        netdev_info(dev, "Link %sreliable\n", reliable ? "" : "un");
        fr_set_link_state(reliable, dev);
    }

    if (state(hdlc)->settings.dce)
        state(hdlc)->timer.expires = jiffies +
            state(hdlc)->settings.t392 * HZ;
    else {
        if (state(hdlc)->n391cnt)
            state(hdlc)->n391cnt--;

        fr_lmi_send(dev, state(hdlc)->n391cnt == 0);

        state(hdlc)->last_poll = jiffies;
        state(hdlc)->request = 1;
        state(hdlc)->timer.expires = jiffies +
            state(hdlc)->settings.t391 * HZ;
    }

    state(hdlc)->timer.function = fr_timer;
    state(hdlc)->timer.data = arg;
    add_timer(&state(hdlc)->timer);
}


static int fr_lmi_recv(struct net_device *dev, struct sk_buff *skb)
{
    hdlc_device *hdlc = dev_to_hdlc(dev);
    pvc_device *pvc;
    u8 rxseq, txseq;
    int lmi = state(hdlc)->settings.lmi;
    int dce = state(hdlc)->settings.dce;
    int stat_len = (lmi == LMI_CISCO) ? 6 : 3, reptype, error, no_ram, i;

    if (skb->len < (lmi == LMI_ANSI ? LMI_ANSI_LENGTH :
            LMI_CCITT_CISCO_LENGTH)) {
        netdev_info(dev, "Short LMI frame\n");
        return 1;
    }

    if (skb->data[3] != (lmi == LMI_CISCO ? NLPID_CISCO_LMI :
                 NLPID_CCITT_ANSI_LMI)) {
        netdev_info(dev, "Received non-LMI frame with LMI DLCI\n");
        return 1;
    }

    if (skb->data[4] != LMI_CALLREF) {
        netdev_info(dev, "Invalid LMI Call reference (0x%02X)\n",
                skb->data[4]);
        return 1;
    }

    if (skb->data[5] != (dce ? LMI_STATUS_ENQUIRY : LMI_STATUS)) {
        netdev_info(dev, "Invalid LMI Message type (0x%02X)\n",
                skb->data[5]);
        return 1;
    }

    if (lmi == LMI_ANSI) {
        if (skb->data[6] != LMI_ANSI_LOCKSHIFT) {
            netdev_info(dev, "Not ANSI locking shift in LMI message (0x%02X)\n",
                    skb->data[6]);
            return 1;
        }
        i = 7;
    } else
        i = 6;

    if (skb->data[i] != (lmi == LMI_CCITT ? LMI_CCITT_REPTYPE :
                 LMI_ANSI_CISCO_REPTYPE)) {
        netdev_info(dev, "Not an LMI Report type IE (0x%02X)\n",
                skb->data[i]);
        return 1;
    }

    if (skb->data[++i] != LMI_REPT_LEN) {
        netdev_info(dev, "Invalid LMI Report type IE length (%u)\n",
                skb->data[i]);
        return 1;
    }

    reptype = skb->data[++i];
    if (reptype != LMI_INTEGRITY && reptype != LMI_FULLREP) {
        netdev_info(dev, "Unsupported LMI Report type (0x%02X)\n",
                reptype);
        return 1;
    }

    if (skb->data[++i] != (lmi == LMI_CCITT ? LMI_CCITT_ALIVE :
                   LMI_ANSI_CISCO_ALIVE)) {
        netdev_info(dev, "Not an LMI Link integrity verification IE (0x%02X)\n",
                skb->data[i]);
        return 1;
    }

    if (skb->data[++i] != LMI_INTEG_LEN) {
        netdev_info(dev, "Invalid LMI Link integrity verification IE length (%u)\n",
                skb->data[i]);
        return 1;
    }
    i++;

    state(hdlc)->rxseq = skb->data[i++]; /* TX sequence from peer */
    rxseq = skb->data[i++]; /* Should confirm our sequence */

    txseq = state(hdlc)->txseq;

    if (dce)
        state(hdlc)->last_poll = jiffies;

    error = 0;
    if (!state(hdlc)->reliable)
        error = 1;

    if (rxseq == 0 || rxseq != txseq) { /* Ask for full report next time */
        state(hdlc)->n391cnt = 0;
        error = 1;
    }

    if (dce) {
        if (state(hdlc)->fullrep_sent && !error) {
/* Stop sending full report - the last one has been confirmed by DTE */
            state(hdlc)->fullrep_sent = 0;
            pvc = state(hdlc)->first_pvc;
            while (pvc) {
                if (pvc->state.new) {
                    pvc->state.new = 0;

/* Tell DTE that new PVC is now active */
                    state(hdlc)->dce_changed = 1;
                }
                pvc = pvc->next;
            }
        }

        if (state(hdlc)->dce_changed) {
            reptype = LMI_FULLREP;
            state(hdlc)->fullrep_sent = 1;
            state(hdlc)->dce_changed = 0;
        }

        state(hdlc)->request = 1; /* got request */
        fr_lmi_send(dev, reptype == LMI_FULLREP ? 1 : 0);
        return 0;
    }

    /* DTE */

    state(hdlc)->request = 0; /* got response, no request pending */

    if (error)
        return 0;

    if (reptype != LMI_FULLREP)
        return 0;

    pvc = state(hdlc)->first_pvc;

    while (pvc) {
        pvc->state.deleted = 1;
        pvc = pvc->next;
    }

    no_ram = 0;
    while (skb->len >= i + 2 + stat_len) {
        u16 dlci;
        u32 bw;
        unsigned int active, new;

        if (skb->data[i] != (lmi == LMI_CCITT ? LMI_CCITT_PVCSTAT :
                       LMI_ANSI_CISCO_PVCSTAT)) {
            netdev_info(dev, "Not an LMI PVC status IE (0x%02X)\n",
                    skb->data[i]);
            return 1;
        }

        if (skb->data[++i] != stat_len) {
            netdev_info(dev, "Invalid LMI PVC status IE length (%u)\n",
                    skb->data[i]);
            return 1;
        }
        i++;

        new = !! (skb->data[i + 2] & 0x08);
        active = !! (skb->data[i + 2] & 0x02);
        if (lmi == LMI_CISCO) {
            dlci = (skb->data[i] << 8) | skb->data[i + 1];
            bw = (skb->data[i + 3] << 16) |
                (skb->data[i + 4] << 8) |
                (skb->data[i + 5]);
        } else {
            dlci = ((skb->data[i] & 0x3F) << 4) |
                ((skb->data[i + 1] & 0x78) >> 3);
            bw = 0;
        }

        pvc = add_pvc(dev, dlci);

        if (!pvc && !no_ram) {
            netdev_warn(dev, "Memory squeeze on fr_lmi_recv()\n");
            no_ram = 1;
        }

        if (pvc) {
            pvc->state.exist = 1;
            pvc->state.deleted = 0;
            if (active != pvc->state.active ||
                new != pvc->state.new ||
                bw != pvc->state.bandwidth ||
                !pvc->state.exist) {
                pvc->state.new = new;
                pvc->state.active = active;
                pvc->state.bandwidth = bw;
                pvc_carrier(active, pvc);
                fr_log_dlci_active(pvc);
            }
        }

        i += stat_len;
    }

    pvc = state(hdlc)->first_pvc;

    while (pvc) {
        if (pvc->state.deleted && pvc->state.exist) {
            pvc_carrier(0, pvc);
            pvc->state.active = pvc->state.new = 0;
            pvc->state.exist = 0;
            pvc->state.bandwidth = 0;
            fr_log_dlci_active(pvc);
        }
        pvc = pvc->next;
    }

    /* Next full report after N391 polls */
    state(hdlc)->n391cnt = state(hdlc)->settings.n391;

    return 0;
}


static int fr_rx(struct sk_buff *skb)
{
    struct net_device *frad = skb->dev;
    hdlc_device *hdlc = dev_to_hdlc(frad);
    fr_hdr *fh = (fr_hdr*)skb->data;
    u8 *data = skb->data;
    u16 dlci;
    pvc_device *pvc;
    struct net_device *dev = NULL;

    if (skb->len <= 4 || fh->ea1 || data[2] != FR_UI)
        goto rx_error;

    dlci = q922_to_dlci(skb->data);

    if ((dlci == LMI_CCITT_ANSI_DLCI &&
         (state(hdlc)->settings.lmi == LMI_ANSI ||
          state(hdlc)->settings.lmi == LMI_CCITT)) ||
        (dlci == LMI_CISCO_DLCI &&
         state(hdlc)->settings.lmi == LMI_CISCO)) {
        if (fr_lmi_recv(frad, skb))
            goto rx_error;
        dev_kfree_skb_any(skb);
        return NET_RX_SUCCESS;
    }

    pvc = find_pvc(hdlc, dlci);
    if (!pvc) {
#ifdef DEBUG_PKT
        netdev_info(frad, "No PVC for received frame's DLCI %d\n",
                dlci);
#endif
        dev_kfree_skb_any(skb);
        return NET_RX_DROP;
    }

    if (pvc->state.fecn != fh->fecn) {
#ifdef DEBUG_ECN
        printk(KERN_DEBUG "%s: DLCI %d FECN O%s\n", frad->name,
               dlci, fh->fecn ? "N" : "FF");
#endif
        pvc->state.fecn ^= 1;
    }

    if (pvc->state.becn != fh->becn) {
#ifdef DEBUG_ECN
        printk(KERN_DEBUG "%s: DLCI %d BECN O%s\n", frad->name,
               dlci, fh->becn ? "N" : "FF");
#endif
        pvc->state.becn ^= 1;
    }


    if ((skb = skb_share_check(skb, GFP_ATOMIC)) == NULL) {
        frad->stats.rx_dropped++;
        return NET_RX_DROP;
    }

    if (data[3] == NLPID_IP) {
        skb_pull(skb, 4); /* Remove 4-byte header (hdr, UI, NLPID) */
        dev = pvc->main;
        skb->protocol = htons(ETH_P_IP);

    } else if (data[3] == NLPID_IPV6) {
        skb_pull(skb, 4); /* Remove 4-byte header (hdr, UI, NLPID) */
        dev = pvc->main;
        skb->protocol = htons(ETH_P_IPV6);

    } else if (skb->len > 10 && data[3] == FR_PAD &&
           data[4] == NLPID_SNAP && data[5] == FR_PAD) {
        u16 oui = ntohs(*(__be16*)(data + 6));
        u16 pid = ntohs(*(__be16*)(data + 8));
        skb_pull(skb, 10);

        switch ((((u32)oui) << 16) | pid) {
        case ETH_P_ARP: /* routed frame with SNAP */
        case ETH_P_IPX:
        case ETH_P_IP:  /* a long variant */
        case ETH_P_IPV6:
            dev = pvc->main;
            skb->protocol = htons(pid);
            break;

        case 0x80C20007: /* bridged Ethernet frame */
            if ((dev = pvc->ether) != NULL)
                skb->protocol = eth_type_trans(skb, dev);
            break;

        default:
            netdev_info(frad, "Unsupported protocol, OUI=%x PID=%x\n",
                    oui, pid);
            dev_kfree_skb_any(skb);
            return NET_RX_DROP;
        }
    } else {
        netdev_info(frad, "Unsupported protocol, NLPID=%x length=%i\n",
                data[3], skb->len);
        dev_kfree_skb_any(skb);
        return NET_RX_DROP;
    }

    if (dev) {
        dev->stats.rx_packets++; /* PVC traffic */
        dev->stats.rx_bytes += skb->len;
        if (pvc->state.becn)
            dev->stats.rx_compressed++;
        skb->dev = dev;
        netif_rx(skb);
        return NET_RX_SUCCESS;
    } else {
        dev_kfree_skb_any(skb);
        return NET_RX_DROP;
    }

 rx_error:
    frad->stats.rx_errors++; /* Mark error */
    dev_kfree_skb_any(skb);
    return NET_RX_DROP;
}



static void fr_start(struct net_device *dev)
{
    hdlc_device *hdlc = dev_to_hdlc(dev);
#ifdef DEBUG_LINK
    printk(KERN_DEBUG "fr_start\n");
#endif
    if (state(hdlc)->settings.lmi != LMI_NONE) {
        state(hdlc)->reliable = 0;
        state(hdlc)->dce_changed = 1;
        state(hdlc)->request = 0;
        state(hdlc)->fullrep_sent = 0;
        state(hdlc)->last_errors = 0xFFFFFFFF;
        state(hdlc)->n391cnt = 0;
        state(hdlc)->txseq = state(hdlc)->rxseq = 0;

        init_timer(&state(hdlc)->timer);
        /* First poll after 1 s */
        state(hdlc)->timer.expires = jiffies + HZ;
        state(hdlc)->timer.function = fr_timer;
        state(hdlc)->timer.data = (unsigned long)dev;
        add_timer(&state(hdlc)->timer);
    } else
        fr_set_link_state(1, dev);
}


static void fr_stop(struct net_device *dev)
{
    hdlc_device *hdlc = dev_to_hdlc(dev);
#ifdef DEBUG_LINK
    printk(KERN_DEBUG "fr_stop\n");
#endif
    if (state(hdlc)->settings.lmi != LMI_NONE)
        del_timer_sync(&state(hdlc)->timer);
    fr_set_link_state(0, dev);
}


static void fr_close(struct net_device *dev)
{
    hdlc_device *hdlc = dev_to_hdlc(dev);
    pvc_device *pvc = state(hdlc)->first_pvc;

    while (pvc) {       /* Shutdown all PVCs for this FRAD */
        if (pvc->main)
            dev_close(pvc->main);
        if (pvc->ether)
            dev_close(pvc->ether);
        pvc = pvc->next;
    }
}


static void pvc_setup(struct net_device *dev)
{
    dev->type = ARPHRD_DLCI;
    dev->flags = IFF_POINTOPOINT;
    dev->hard_header_len = 10;
    dev->addr_len = 2;
    dev->priv_flags &= ~IFF_XMIT_DST_RELEASE;
}

static const struct net_device_ops pvc_ops = {
    .ndo_open       = pvc_open,
    .ndo_stop       = pvc_close,
    .ndo_change_mtu = hdlc_change_mtu,
    .ndo_start_xmit = pvc_xmit,
    .ndo_do_ioctl   = pvc_ioctl,
};

static int fr_add_pvc(struct net_device *frad, unsigned int dlci, int type)
{
    hdlc_device *hdlc = dev_to_hdlc(frad);
    pvc_device *pvc;
    struct net_device *dev;
    int used;

    if ((pvc = add_pvc(frad, dlci)) == NULL) {
        netdev_warn(frad, "Memory squeeze on fr_add_pvc()\n");
        return -ENOBUFS;
    }

    if (*get_dev_p(pvc, type))
        return -EEXIST;

    used = pvc_is_used(pvc);

    if (type == ARPHRD_ETHER) {
        dev = alloc_netdev(0, "pvceth%d", ether_setup);
        dev->priv_flags &= ~IFF_TX_SKB_SHARING;
    } else
        dev = alloc_netdev(0, "pvc%d", pvc_setup);

    if (!dev) {
        netdev_warn(frad, "Memory squeeze on fr_pvc()\n");
        delete_unused_pvcs(hdlc);
        return -ENOBUFS;
    }

    if (type == ARPHRD_ETHER)
        eth_hw_addr_random(dev);
    else {
        *(__be16*)dev->dev_addr = htons(dlci);
        dlci_to_q922(dev->broadcast, dlci);
    }
    dev->netdev_ops = &pvc_ops;
    dev->mtu = HDLC_MAX_MTU;
    dev->tx_queue_len = 0;
    dev->ml_priv = pvc;

    if (register_netdevice(dev) != 0) {
        free_netdev(dev);
        delete_unused_pvcs(hdlc);
        return -EIO;
    }

    dev->destructor = free_netdev;
    *get_dev_p(pvc, type) = dev;
    if (!used) {
        state(hdlc)->dce_changed = 1;
        state(hdlc)->dce_pvc_count++;
    }
    return 0;
}



static int fr_del_pvc(hdlc_device *hdlc, unsigned int dlci, int type)
{
    pvc_device *pvc;
    struct net_device *dev;

    if ((pvc = find_pvc(hdlc, dlci)) == NULL)
        return -ENOENT;

    if ((dev = *get_dev_p(pvc, type)) == NULL)
        return -ENOENT;

    if (dev->flags & IFF_UP)
        return -EBUSY;      /* PVC in use */

    unregister_netdevice(dev); /* the destructor will free_netdev(dev) */
    *get_dev_p(pvc, type) = NULL;

    if (!pvc_is_used(pvc)) {
        state(hdlc)->dce_pvc_count--;
        state(hdlc)->dce_changed = 1;
    }
    delete_unused_pvcs(hdlc);
    return 0;
}



static void fr_destroy(struct net_device *frad)
{
    hdlc_device *hdlc = dev_to_hdlc(frad);
    pvc_device *pvc = state(hdlc)->first_pvc;
    state(hdlc)->first_pvc = NULL; /* All PVCs destroyed */
    state(hdlc)->dce_pvc_count = 0;
    state(hdlc)->dce_changed = 1;

    while (pvc) {
        pvc_device *next = pvc->next;
        /* destructors will free_netdev() main and ether */
        if (pvc->main)
            unregister_netdevice(pvc->main);

        if (pvc->ether)
            unregister_netdevice(pvc->ether);

        kfree(pvc);
        pvc = next;
    }
}


static struct hdlc_proto proto = {
    .close      = fr_close,
    .start      = fr_start,
    .stop       = fr_stop,
    .detach     = fr_destroy,
    .ioctl      = fr_ioctl,
    .netif_rx   = fr_rx,
    .module     = THIS_MODULE,
};


static int fr_ioctl(struct net_device *dev, struct ifreq *ifr)
{
    fr_proto __user *fr_s = ifr->ifr_settings.ifs_ifsu.fr;
    const size_t size = sizeof(fr_proto);
    fr_proto new_settings;
    hdlc_device *hdlc = dev_to_hdlc(dev);
    fr_proto_pvc pvc;
    int result;

    switch (ifr->ifr_settings.type) {
    case IF_GET_PROTO:
        if (dev_to_hdlc(dev)->proto != &proto) /* Different proto */
            return -EINVAL;
        ifr->ifr_settings.type = IF_PROTO_FR;
        if (ifr->ifr_settings.size < size) {
            ifr->ifr_settings.size = size; /* data size wanted */
            return -ENOBUFS;
        }
        if (copy_to_user(fr_s, &state(hdlc)->settings, size))
            return -EFAULT;
        return 0;

    case IF_PROTO_FR:
        if (!capable(CAP_NET_ADMIN))
            return -EPERM;

        if (dev->flags & IFF_UP)
            return -EBUSY;

        if (copy_from_user(&new_settings, fr_s, size))
            return -EFAULT;

        if (new_settings.lmi == LMI_DEFAULT)
            new_settings.lmi = LMI_ANSI;

        if ((new_settings.lmi != LMI_NONE &&
             new_settings.lmi != LMI_ANSI &&
             new_settings.lmi != LMI_CCITT &&
             new_settings.lmi != LMI_CISCO) ||
            new_settings.t391 < 1 ||
            new_settings.t392 < 2 ||
            new_settings.n391 < 1 ||
            new_settings.n392 < 1 ||
            new_settings.n393 < new_settings.n392 ||
            new_settings.n393 > 32 ||
            (new_settings.dce != 0 &&
             new_settings.dce != 1))
            return -EINVAL;

        result=hdlc->attach(dev, ENCODING_NRZ,PARITY_CRC16_PR1_CCITT);
        if (result)
            return result;

        if (dev_to_hdlc(dev)->proto != &proto) { /* Different proto */
            result = attach_hdlc_protocol(dev, &proto,
                              sizeof(struct frad_state));
            if (result)
                return result;
            state(hdlc)->first_pvc = NULL;
            state(hdlc)->dce_pvc_count = 0;
        }
        memcpy(&state(hdlc)->settings, &new_settings, size);
        dev->type = ARPHRD_FRAD;
        return 0;

    case IF_PROTO_FR_ADD_PVC:
    case IF_PROTO_FR_DEL_PVC:
    case IF_PROTO_FR_ADD_ETH_PVC:
    case IF_PROTO_FR_DEL_ETH_PVC:
        if (dev_to_hdlc(dev)->proto != &proto) /* Different proto */
            return -EINVAL;

        if (!capable(CAP_NET_ADMIN))
            return -EPERM;

        if (copy_from_user(&pvc, ifr->ifr_settings.ifs_ifsu.fr_pvc,
                   sizeof(fr_proto_pvc)))
            return -EFAULT;

        if (pvc.dlci <= 0 || pvc.dlci >= 1024)
            return -EINVAL; /* Only 10 bits, DLCI 0 reserved */

        if (ifr->ifr_settings.type == IF_PROTO_FR_ADD_ETH_PVC ||
            ifr->ifr_settings.type == IF_PROTO_FR_DEL_ETH_PVC)
            result = ARPHRD_ETHER; /* bridged Ethernet device */
        else
            result = ARPHRD_DLCI;

        if (ifr->ifr_settings.type == IF_PROTO_FR_ADD_PVC ||
            ifr->ifr_settings.type == IF_PROTO_FR_ADD_ETH_PVC)
            return fr_add_pvc(dev, pvc.dlci, result);
        else
            return fr_del_pvc(hdlc, pvc.dlci, result);
    }

    return -EINVAL;
}


static int __init mod_init(void)
{
    register_hdlc_protocol(&proto);
    return 0;
}


static void __exit mod_exit(void)
{
    unregister_hdlc_protocol(&proto);
}


module_init(mod_init);
module_exit(mod_exit);

MODULE_AUTHOR("Krzysztof Halasa <[email protected]>");
MODULE_DESCRIPTION("Frame-Relay protocol support for generic HDLC");
MODULE_LICENSE("GPL v2");