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/*

 * NET3:        Token ring device handling subroutines

 *

 *              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.

 *

 * Fixes:       3 Feb 97 Paul Norton <pnorton@cts.com> Minor routing fixes.

 *              Added rif table to /proc/net/tr_rif and rif timeout to

 *              /proc/sys/net/token-ring/rif_timeout.

 *              22 Jun 98 Paul Norton <p.norton@computer.org> Rearranged

 *              tr_header and tr_type_trans to handle passing IPX SNAP and

 *              802.2 through the correct layers. Eliminated tr_reformat.

 *

 */

#include <asm/uaccess.h>

#include <asm/system.h>

#include <linux/module.h>

#include <linux/types.h>

#include <linux/kernel.h>

#include <linux/jiffies.h>

#include <linux/string.h>

#include <linux/mm.h>

#include <linux/socket.h>

#include <linux/in.h>

#include <linux/inet.h>

#include <linux/netdevice.h>

#include <linux/trdevice.h>

#include <linux/skbuff.h>

#include <linux/errno.h>

#include <linux/timer.h>

#include <linux/net.h>

#include <linux/proc_fs.h>

#include <linux/seq_file.h>

#include <linux/init.h>

#include <net/arp.h>

#include <net/net_namespace.h>

static void tr_add_rif_info(struct trh_hdr *trh, struct net_device *dev);

static void rif_check_expire(unsigned long dummy);

#define TR_SR_DEBUG 0

/*

 *      Each RIF entry we learn is kept this way

 */

struct rif_cache {

        unsigned char addr[TR_ALEN];

        int iface;

        __be16 rcf;

        __be16 rseg[8];

        struct rif_cache *next;

        unsigned long last_used;

        unsigned char local_ring;

};

#define RIF_TABLE_SIZE 32

/*

 *      We hash the RIF cache 32 ways. We do after all have to look it

 *      up a lot.

 */

static struct rif_cache *rif_table[RIF_TABLE_SIZE];

static DEFINE_SPINLOCK(rif_lock);

/*

 *      Garbage disposal timer.

 */

static struct timer_list rif_timer;

int sysctl_tr_rif_timeout = 60*10*HZ;

static inline unsigned long rif_hash(const unsigned char *addr)

{

        unsigned long x;

        x = addr[0];

        x = (x << 2) ^ addr[1];

        x = (x << 2) ^ addr[2];

        x = (x << 2) ^ addr[3];

        x = (x << 2) ^ addr[4];

        x = (x << 2) ^ addr[5];

        x ^= x >> 8;

        return x & (RIF_TABLE_SIZE - 1);

}

/*

 *      Put the headers on a token ring packet. Token ring source routing

 *      makes this a little more exciting than on ethernet.

 */

static int tr_header(struct sk_buff *skb, struct net_device *dev,

                     unsigned short type,

                     const void *daddr, const void *saddr, unsigned len)

{

        struct trh_hdr *trh;

        int hdr_len;

        /*

         * Add the 802.2 SNAP header if IP as the IPv4/IPv6 code calls

         * dev->hard_header directly.

         */

        if (type == ETH_P_IP || type == ETH_P_IPV6 || type == ETH_P_ARP)

        {

                struct trllc *trllc;

                hdr_len = sizeof(struct trh_hdr) + sizeof(struct trllc);

                trh = (struct trh_hdr *)skb_push(skb, hdr_len);

                trllc = (struct trllc *)(trh+1);

                trllc->dsap = trllc->ssap = EXTENDED_SAP;

                trllc->llc = UI_CMD;

                trllc->protid[0] = trllc->protid[1] = trllc->protid[2] = 0x00;

                trllc->ethertype = htons(type);

        }

        else

        {

                hdr_len = sizeof(struct trh_hdr);

                trh = (struct trh_hdr *)skb_push(skb, hdr_len);

        }

        trh->ac=AC;

        trh->fc=LLC_FRAME;

        if(saddr)

                memcpy(trh->saddr,saddr,dev->addr_len);

        else

                memcpy(trh->saddr,dev->dev_addr,dev->addr_len);

        /*

         *      Build the destination and then source route the frame

         */

        if(daddr)

        {

                memcpy(trh->daddr,daddr,dev->addr_len);

                tr_source_route(skb, trh, dev);

                return(hdr_len);

        }

        return -hdr_len;

}

/*

 *      A neighbour discovery of some species (eg arp) has completed. We

 *      can now send the packet.

 */

static int tr_rebuild_header(struct sk_buff *skb)

{

        struct trh_hdr *trh=(struct trh_hdr *)skb->data;

        struct trllc *trllc=(struct trllc *)(skb->data+sizeof(struct trh_hdr));

        struct net_device *dev = skb->dev;

        /*

         *      FIXME: We don't yet support IPv6 over token rings

         */

        if(trllc->ethertype != htons(ETH_P_IP)) {

                printk("tr_rebuild_header: Don't know how to resolve type %04X addresses ?\n", ntohs(trllc->ethertype));

                return 0;

        }

#ifdef CONFIG_INET

        if(arp_find(trh->daddr, skb)) {

                        return 1;

        }

        else

#endif

        {

                tr_source_route(skb,trh,dev);

                return 0;

        }

}

/*

 *      Some of this is a bit hackish. We intercept RIF information

 *      used for source routing. We also grab IP directly and don't feed

 *      it via SNAP.

 */

__be16 tr_type_trans(struct sk_buff *skb, struct net_device *dev)

{

        struct trh_hdr *trh;

        struct trllc *trllc;

        unsigned riflen=0;

        skb->dev = dev;

        skb_reset_mac_header(skb);

        trh = tr_hdr(skb);

        if(trh->saddr[0] & TR_RII)

                riflen = (ntohs(trh->rcf) & TR_RCF_LEN_MASK) >> 8;

        trllc = (struct trllc *)(skb->data+sizeof(struct trh_hdr)-TR_MAXRIFLEN+riflen);

        skb_pull(skb,sizeof(struct trh_hdr)-TR_MAXRIFLEN+riflen);

        if(*trh->daddr & 0x80)

        {

                if(!memcmp(trh->daddr,dev->broadcast,TR_ALEN))

                        skb->pkt_type=PACKET_BROADCAST;

                else

                        skb->pkt_type=PACKET_MULTICAST;

        }

        else if ( (trh->daddr[0] & 0x01) && (trh->daddr[1] & 0x00) && (trh->daddr[2] & 0x5E))

        {

                skb->pkt_type=PACKET_MULTICAST;

        }

        else if(dev->flags & IFF_PROMISC)

        {

                if(memcmp(trh->daddr, dev->dev_addr, TR_ALEN))

                        skb->pkt_type=PACKET_OTHERHOST;

        }

        if ((skb->pkt_type != PACKET_BROADCAST) &&

            (skb->pkt_type != PACKET_MULTICAST))

                tr_add_rif_info(trh,dev) ;

        /*

         * Strip the SNAP header from ARP packets since we don't

         * pass them through to the 802.2/SNAP layers.

         */

        if (trllc->dsap == EXTENDED_SAP &&

            (trllc->ethertype == htons(ETH_P_IP) ||

             trllc->ethertype == htons(ETH_P_IPV6) ||

             trllc->ethertype == htons(ETH_P_ARP)))

        {

                skb_pull(skb, sizeof(struct trllc));

                return trllc->ethertype;

        }

        return htons(ETH_P_TR_802_2);

}

/*

 *      We try to do source routing...

 */

void tr_source_route(struct sk_buff *skb,struct trh_hdr *trh,

                     struct net_device *dev)

{

        int slack;

        unsigned int hash;

        struct rif_cache *entry;

        unsigned char *olddata;

        unsigned long flags;

        static const unsigned char mcast_func_addr[]

                = {0xC0,0x00,0x00,0x04,0x00,0x00};

        spin_lock_irqsave(&rif_lock, flags);

        /*

         *      Broadcasts are single route as stated in RFC 1042

         */

        if( (!memcmp(&(trh->daddr[0]),&(dev->broadcast[0]),TR_ALEN)) ||

            (!memcmp(&(trh->daddr[0]),&(mcast_func_addr[0]), TR_ALEN))  )

        {

                trh->rcf=htons((((sizeof(trh->rcf)) << 8) & TR_RCF_LEN_MASK)

                               | TR_RCF_FRAME2K | TR_RCF_LIMITED_BROADCAST);

                trh->saddr[0]|=TR_RII;

        }

        else

        {

                hash = rif_hash(trh->daddr);

                /*

                 *      Walk the hash table and look for an entry

                 */

                for(entry=rif_table[hash];entry && memcmp(&(entry->addr[0]),&(trh->daddr[0]),TR_ALEN);entry=entry->next);

                /*

                 *      If we found an entry we can route the frame.

                 */

                if(entry)

                {

#if TR_SR_DEBUG

{

DECLARE_MAC_BUF(mac);

printk("source routing for %s\n",print_mac(mac, trh->daddr));

}

#endif

                        if(!entry->local_ring && (ntohs(entry->rcf) & TR_RCF_LEN_MASK) >> 8)

                        {

                                trh->rcf=entry->rcf;

                                memcpy(&trh->rseg[0],&entry->rseg[0],8*sizeof(unsigned short));

                                trh->rcf^=htons(TR_RCF_DIR_BIT);

                                trh->rcf&=htons(0x1fff);        /* Issam Chehab <ichehab@madge1.demon.co.uk> */

                                trh->saddr[0]|=TR_RII;

#if TR_SR_DEBUG

                                printk("entry found with rcf %04x\n", entry->rcf);

                        }

                        else

                        {

                                printk("entry found but without rcf length, local=%02x\n", entry->local_ring);

#endif

                        }

                        entry->last_used=jiffies;

                }

                else

                {

                        /*

                         *      Without the information we simply have to shout

                         *      on the wire. The replies should rapidly clean this

                         *      situation up.

                         */

                        trh->rcf=htons((((sizeof(trh->rcf)) << 8) & TR_RCF_LEN_MASK)

                                       | TR_RCF_FRAME2K | TR_RCF_LIMITED_BROADCAST);

                        trh->saddr[0]|=TR_RII;

#if TR_SR_DEBUG

                        printk("no entry in rif table found - broadcasting frame\n");

#endif

                }

        }

        /* Compress the RIF here so we don't have to do it in the driver(s) */

        if (!(trh->saddr[0] & 0x80))

                slack = 18;

        else

                slack = 18 - ((ntohs(trh->rcf) & TR_RCF_LEN_MASK)>>8);

        olddata = skb->data;

        spin_unlock_irqrestore(&rif_lock, flags);

        skb_pull(skb, slack);

        memmove(skb->data, olddata, sizeof(struct trh_hdr) - slack);

}

/*

 *      We have learned some new RIF information for our source

 *      routing.

 */

static void tr_add_rif_info(struct trh_hdr *trh, struct net_device *dev)

{

        unsigned int hash, rii_p = 0;

        unsigned long flags;

        struct rif_cache *entry;

        unsigned char saddr0;

        spin_lock_irqsave(&rif_lock, flags);

        saddr0 = trh->saddr[0];

        /*

         *      Firstly see if the entry exists

         */

        if(trh->saddr[0] & TR_RII)

        {

                trh->saddr[0]&=0x7f;

                if (((ntohs(trh->rcf) & TR_RCF_LEN_MASK) >> 8) > 2)

                {

                        rii_p = 1;

                }

        }

        hash = rif_hash(trh->saddr);

        for(entry=rif_table[hash];entry && memcmp(&(entry->addr[0]),&(trh->saddr[0]),TR_ALEN);entry=entry->next);

        if(entry==NULL)

        {

#if TR_SR_DEBUG

                DECLARE_MAC_BUF(mac);

                printk("adding rif_entry: addr:%s rcf:%04X\n",

                       print_mac(mac, trh->saddr), ntohs(trh->rcf));

#endif

                /*

                 *      Allocate our new entry. A failure to allocate loses

                 *      use the information. This is harmless.

                 *

                 *      FIXME: We ought to keep some kind of cache size

                 *      limiting and adjust the timers to suit.

                 */

                entry=kmalloc(sizeof(struct rif_cache),GFP_ATOMIC);

                if(!entry)

                {

                        printk(KERN_DEBUG "tr.c: Couldn't malloc rif cache entry !\n");

                        spin_unlock_irqrestore(&rif_lock, flags);

                        return;

                }

                memcpy(&(entry->addr[0]),&(trh->saddr[0]),TR_ALEN);

                entry->iface = dev->ifindex;

                entry->next=rif_table[hash];

                entry->last_used=jiffies;

                rif_table[hash]=entry;

                if (rii_p)

                {

                        entry->rcf = trh->rcf & htons((unsigned short)~TR_RCF_BROADCAST_MASK);

                        memcpy(&(entry->rseg[0]),&(trh->rseg[0]),8*sizeof(unsigned short));

                        entry->local_ring = 0;

                }

                else

                {

                        entry->local_ring = 1;

                }

        }

        else    /* Y. Tahara added */

        {

                /*

                 *      Update existing entries

                 */

                if (!entry->local_ring)

                    if (entry->rcf != (trh->rcf & htons((unsigned short)~TR_RCF_BROADCAST_MASK)) &&

                         !(trh->rcf & htons(TR_RCF_BROADCAST_MASK)))

                    {

#if TR_SR_DEBUG

{

DECLARE_MAC_BUF(mac);

printk("updating rif_entry: addr:%s rcf:%04X\n",

                print_mac(mac, trh->saddr), ntohs(trh->rcf));

}

#endif

                            entry->rcf = trh->rcf & htons((unsigned short)~TR_RCF_BROADCAST_MASK);

                            memcpy(&(entry->rseg[0]),&(trh->rseg[0]),8*sizeof(unsigned short));

                    }

                entry->last_used=jiffies;

        }

        trh->saddr[0]=saddr0; /* put the routing indicator back for tcpdump */

        spin_unlock_irqrestore(&rif_lock, flags);

}

/*

 *      Scan the cache with a timer and see what we need to throw out.

 */

static void rif_check_expire(unsigned long dummy)

{

        int i;

        unsigned long flags, next_interval = jiffies + sysctl_tr_rif_timeout/2;

        spin_lock_irqsave(&rif_lock, flags);

        for(i =0; i < RIF_TABLE_SIZE; i++) {

                struct rif_cache *entry, **pentry;

                pentry = rif_table+i;

                while((entry=*pentry) != NULL) {

                        unsigned long expires

                                = entry->last_used + sysctl_tr_rif_timeout;

                        if (time_before_eq(expires, jiffies)) {

                                *pentry = entry->next;

                                kfree(entry);

                        } else {

                                pentry = &entry->next;

                                if (time_before(expires, next_interval))

                                        next_interval = expires;

                        }

                }

        }

        spin_unlock_irqrestore(&rif_lock, flags);

        mod_timer(&rif_timer, next_interval);

}

/*

 *      Generate the /proc/net information for the token ring RIF

 *      routing.

 */

#ifdef CONFIG_PROC_FS

static struct rif_cache *rif_get_idx(loff_t pos)

{

        int i;

        struct rif_cache *entry;

        loff_t off = 0;

        for(i = 0; i < RIF_TABLE_SIZE; i++)

                for(entry = rif_table[i]; entry; entry = entry->next) {

                        if (off == pos)

                                return entry;

                        ++off;

                }

        return NULL;

}

static void *rif_seq_start(struct seq_file *seq, loff_t *pos)

{

        spin_lock_irq(&rif_lock);

        return *pos ? rif_get_idx(*pos - 1) : SEQ_START_TOKEN;

}

static void *rif_seq_next(struct seq_file *seq, void *v, loff_t *pos)

{

        int i;

        struct rif_cache *ent = v;

        ++*pos;

        if (v == SEQ_START_TOKEN) {

                i = -1;

                goto scan;

        }

        if (ent->next)

                return ent->next;

        i = rif_hash(ent->addr);

 scan:

        while (++i < RIF_TABLE_SIZE) {

                if ((ent = rif_table[i]) != NULL)

                        return ent;

        }

        return NULL;

}

static void rif_seq_stop(struct seq_file *seq, void *v)

{

        spin_unlock_irq(&rif_lock);

}

static int rif_seq_show(struct seq_file *seq, void *v)

{

        int j, rcf_len, segment, brdgnmb;

        struct rif_cache *entry = v;

        DECLARE_MAC_BUF(mac);

        if (v == SEQ_START_TOKEN)

                seq_puts(seq,

                     "if     TR address       TTL   rcf   routing segments\n");

        else {

                struct net_device *dev = dev_get_by_index(&init_net, entry->iface);

                long ttl = (long) (entry->last_used + sysctl_tr_rif_timeout)

                                - (long) jiffies;

                seq_printf(seq, "%s %s %7li ",

                           dev?dev->name:"?",

                           print_mac(mac, entry->addr),

                           ttl/HZ);

                        if (entry->local_ring)

                                seq_puts(seq, "local\n");

                        else {

                                seq_printf(seq, "%04X", ntohs(entry->rcf));

                                rcf_len = ((ntohs(entry->rcf) & TR_RCF_LEN_MASK)>>8)-2;

                                if (rcf_len)

                                        rcf_len >>= 1;

                                for(j = 1; j < rcf_len; j++) {

                                        if(j==1) {

                                                segment=ntohs(entry->rseg[j-1])>>4;

                                                seq_printf(seq,"  %03X",segment);

                                        }

                                        segment=ntohs(entry->rseg[j])>>4;

                                        brdgnmb=ntohs(entry->rseg[j-1])&0x00f;

                                        seq_printf(seq,"-%01X-%03X",brdgnmb,segment);

                                }

                                seq_putc(seq, '\n');

                        }

                }

        return 0;

}

static const struct seq_operations rif_seq_ops = {

        .start = rif_seq_start,

        .next  = rif_seq_next,

        .stop  = rif_seq_stop,

        .show  = rif_seq_show,

};

static int rif_seq_open(struct inode *inode, struct file *file)

{

        return seq_open(file, &rif_seq_ops);

}

static const struct file_operations rif_seq_fops = {

        .owner   = THIS_MODULE,

        .open    = rif_seq_open,

        .read    = seq_read,

        .llseek  = seq_lseek,

        .release = seq_release,

};

#endif

static const struct header_ops tr_header_ops = {

        .create = tr_header,

        .rebuild= tr_rebuild_header,

};

static void tr_setup(struct net_device *dev)

{

        /*

         *      Configure and register

         */

        dev->header_ops = &tr_header_ops;

        dev->type               = ARPHRD_IEEE802_TR;

        dev->hard_header_len    = TR_HLEN;

        dev->mtu                = 2000;

        dev->addr_len           = TR_ALEN;

        dev->tx_queue_len       = 100;  /* Long queues on tr */

        memset(dev->broadcast,0xFF, TR_ALEN);

        /* New-style flags. */

        dev->flags              = IFF_BROADCAST | IFF_MULTICAST ;

}

/**

 * alloc_trdev - Register token ring device

 * @sizeof_priv: Size of additional driver-private structure to be allocated

 *      for this token ring device

 *

 * Fill in the fields of the device structure with token ring-generic values.

 *

 * Constructs a new net device, complete with a private data area of

 * size @sizeof_priv.  A 32-byte (not bit) alignment is enforced for

 * this private data area.

 */

struct net_device *alloc_trdev(int sizeof_priv)

{

        return alloc_netdev(sizeof_priv, "tr%d", tr_setup);

}

/*

 *      Called during bootup.  We don't actually have to initialise

 *      too much for this.

 */

static int __init rif_init(void)

{

        init_timer(&rif_timer);

        rif_timer.expires  = jiffies + sysctl_tr_rif_timeout;

        rif_timer.data     = 0L;

        rif_timer.function = rif_check_expire;

        add_timer(&rif_timer);

        proc_net_fops_create(&init_net, "tr_rif", S_IRUGO, &rif_seq_fops);

        return 0;

}

module_init(rif_init);

EXPORT_SYMBOL(tr_type_trans);