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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/config.h>

#include <linux/types.h>

#include <linux/kernel.h>

#include <linux/sched.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/init.h>

#include <net/arp.h>

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

                     struct net_device *dev);

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

typedef struct rif_cache_s *rif_cache;

/*

 *      Each RIF entry we learn is kept this way

 */

struct rif_cache_s {

        unsigned char addr[TR_ALEN];

        int iface;

        __u16 rcf;

        __u16 rseg[8];

        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 rif_cache rif_table[RIF_TABLE_SIZE];

static spinlock_t rif_lock = SPIN_LOCK_UNLOCKED;

#define RIF_TIMEOUT 60*10*HZ

#define RIF_CHECK_INTERVAL 60*HZ

/*

 *      Garbage disposal timer.

 */

static struct timer_list rif_timer;

int sysctl_tr_rif_timeout = RIF_TIMEOUT;

/*

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

 *      makes this a little more exciting than on ethernet.

 */

int tr_header(struct sk_buff *skb, struct net_device *dev, unsigned short type,

              void *daddr, 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=(struct trllc *)(trh+1);

                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.

 */

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",(unsigned int)htons(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.

 */

unsigned short tr_type_trans(struct sk_buff *skb, struct net_device *dev)

{

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

        struct trllc *trllc;

        unsigned riflen=0;

        skb->mac.raw = skb->data;

        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 == ntohs(ETH_P_IP) ||

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

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

        {

                skb_pull(skb, sizeof(struct trllc));

                return trllc->ethertype;

        }

        return ntohs(ETH_P_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 i, slack;

        unsigned int hash;

        rif_cache entry;

        unsigned char *olddata;

        unsigned char mcast_func_addr[] = {0xC0,0x00,0x00,0x04,0x00,0x00};

        unsigned long flags ;

        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

        {

                for(i=0,hash=0;i<TR_ALEN;hash+=trh->daddr[i++]);

                hash&=RIF_TABLE_SIZE-1;

                /*

                 *      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

printk("source routing for %02X:%02X:%02X:%02X:%02X:%02X\n",trh->daddr[0],

                  trh->daddr[1],trh->daddr[2],trh->daddr[3],trh->daddr[4],trh->daddr[5]);

#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)

{

        int i;

        unsigned int hash, rii_p = 0;

        rif_cache entry;

        unsigned long flags;

        spin_lock_irqsave(&rif_lock, flags);

        /*

         *      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;

                }

        }

        for(i=0,hash=0;i<TR_ALEN;hash+=trh->saddr[i++]);

        hash&=RIF_TABLE_SIZE-1;

        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

printk("adding rif_entry: addr:%02X:%02X:%02X:%02X:%02X:%02X rcf:%04X\n",

                trh->saddr[0],trh->saddr[1],trh->saddr[2],

                trh->saddr[3],trh->saddr[4],trh->saddr[5],

                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_s),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;

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

                }

                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

printk("updating rif_entry: addr:%02X:%02X:%02X:%02X:%02X:%02X rcf:%04X\n",

                trh->saddr[0],trh->saddr[1],trh->saddr[2],

                trh->saddr[3],trh->saddr[4],trh->saddr[5],

                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;

        }

        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 now=jiffies;

        unsigned long flags ;

        spin_lock_irqsave(&rif_lock,flags);

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

        {

                rif_cache entry, *pentry=rif_table+i;

                while((entry=*pentry))

                {

                        /*

                         *      Out it goes

                         */

                        if((now-entry->last_used) > sysctl_tr_rif_timeout)

                        {

                                *pentry=entry->next;

                                kfree(entry);

                        }

                        else

                                pentry=&entry->next;

                }

        }

        spin_unlock_irqrestore(&rif_lock,flags);

        /*

         *      Reset the timer

         */

        mod_timer(&rif_timer, jiffies+sysctl_tr_rif_timeout);

}

/*

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

 *      routing.

 */

#ifndef CONFIG_PROC_FS

static int rif_get_info(char *buffer,char **start, off_t offset, int length)  { return 0;}

#else

static int rif_get_info(char *buffer,char **start, off_t offset, int length)

{

        int len=0;

        off_t begin=0;

        off_t pos=0;

        int size,i,j,rcf_len,segment,brdgnmb;

        unsigned long now=jiffies;

        unsigned long flags;

        rif_cache entry;

        size=sprintf(buffer,

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

        pos+=size;

        len+=size;

        spin_lock_irqsave(&rif_lock, flags);

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

        {

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

                        struct net_device *dev = __dev_get_by_index(entry->iface);

                        size=sprintf(buffer+len,"%s %02X:%02X:%02X:%02X:%02X:%02X %7li ",

                                     dev?dev->name:"?",entry->addr[0],entry->addr[1],entry->addr[2],entry->addr[3],entry->addr[4],entry->addr[5],

                                     sysctl_tr_rif_timeout-(now-entry->last_used));

                        len+=size;

                        pos=begin+len;

                        if (entry->local_ring)

                                size=sprintf(buffer+len,"local\n");

                        else {

                                size=sprintf(buffer+len,"%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;

                                                len+=size;

                                                pos=begin+len;

                                                size=sprintf(buffer+len,"  %03X",segment);

                                        };

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

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

                                        len+=size;

                                        pos=begin+len;

                                        size=sprintf(buffer+len,"-%01X-%03X",brdgnmb,segment);

                                }

                                len+=size;

                                pos=begin+len;

                                size=sprintf(buffer+len,"\n");

                        }

                        len+=size;

                        pos=begin+len;

                        if(pos<offset)

                        {

                                len=0;

                                begin=pos;

                        }

                        if(pos>offset+length)

                                break;

                }

                if(pos>offset+length)

                        break;

        }

        spin_unlock_irqrestore(&rif_lock,flags);

        *start=buffer+(offset-begin); /* Start of wanted data */

        len-=(offset-begin);    /* Start slop */

        if(len>length)

                len=length;    /* Ending slop */

        if (len<0)

                len=0;

        return len;

}

#endif

/*

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

 *      too much for this.

 */

static int __init rif_init(void)

{

        rif_timer.expires  = RIF_TIMEOUT;

        rif_timer.data     = 0L;

        rif_timer.function = rif_check_expire;

        init_timer(&rif_timer);

        add_timer(&rif_timer);

        proc_net_create("tr_rif",0,rif_get_info);

        return 0;

}

module_init(rif_init);