Subversion Repositories or1k

/*

 * DECnet       An implementation of the DECnet protocol suite for the LINUX

 *              operating system.  DECnet is implemented using the  BSD Socket

 *              interface as the means of communication with the user level.

 *

 *              DECnet Network Services Protocol (Output)

 *

 * Author:      Eduardo Marcelo Serrat <emserrat@geocities.com>

 *

 * Changes:

 *

 *    Steve Whitehouse:  Split into dn_nsp_in.c and dn_nsp_out.c from

 *                       original dn_nsp.c.

 *    Steve Whitehouse:  Updated to work with my new routing architecture.

 *    Steve Whitehouse:  Added changes from Eduardo Serrat's patches.

 *    Steve Whitehouse:  Now conninits have the "return" bit set.

 *    Steve Whitehouse:  Fixes to check alloc'd skbs are non NULL!

 *                       Moved output state machine into one function

 *    Steve Whitehouse:  New output state machine

 *         Paul Koning:  Connect Confirm message fix.

 *      Eduardo Serrat:  Fix to stop dn_nsp_do_disc() sending malformed packets.

 *    Steve Whitehouse:  dn_nsp_output() and friends needed a spring clean

 */

/******************************************************************************

    (c) 1995-1998 E.M. Serrat           emserrat@geocities.com

    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

    any later version.

    This program is distributed in the hope that it will be useful,

    but WITHOUT ANY WARRANTY; without even the implied warranty of

    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

    GNU General Public License for more details.

*******************************************************************************/

#include <linux/errno.h>

#include <linux/types.h>

#include <linux/socket.h>

#include <linux/in.h>

#include <linux/kernel.h>

#include <linux/sched.h>

#include <linux/timer.h>

#include <linux/string.h>

#include <linux/sockios.h>

#include <linux/net.h>

#include <linux/netdevice.h>

#include <linux/inet.h>

#include <linux/route.h>

#include <net/sock.h>

#include <asm/segment.h>

#include <asm/system.h>

#include <linux/fcntl.h>

#include <linux/mm.h>

#include <linux/termios.h>      

#include <linux/interrupt.h>

#include <linux/proc_fs.h>

#include <linux/stat.h>

#include <linux/init.h>

#include <linux/poll.h>

#include <linux/if_packet.h>

#include <net/neighbour.h>

#include <net/dst.h>

#include <net/dn_nsp.h>

#include <net/dn_dev.h>

#include <net/dn_route.h>

static int nsp_backoff[NSP_MAXRXTSHIFT + 1] = { 1, 2, 4, 8, 16, 32, 64, 64, 64, 64, 64, 64, 64 };

/*

 * If sk == NULL, then we assume that we are supposed to be making

 * a routing layer skb. If sk != NULL, then we are supposed to be

 * creating an skb for the NSP layer.

 *

 * The eventual aim is for each socket to have a cached header size

 * for its outgoing packets, and to set hdr from this when sk != NULL.

 */

struct sk_buff *dn_alloc_skb(struct sock *sk, int size, int pri)

{

        struct sk_buff *skb;

        int hdr = 64;

        if ((skb = alloc_skb(size + hdr, pri)) == NULL)

                return NULL;

        skb->protocol = __constant_htons(ETH_P_DNA_RT);

        skb->pkt_type = PACKET_OUTGOING;

        if (sk)

                skb_set_owner_w(skb, sk);

        skb_reserve(skb, hdr);

        return skb;

}

/*

 * Wrapper for the above, for allocs of data skbs. We try and get the

 * whole size thats been asked for (plus 11 bytes of header). If this

 * fails, then we try for any size over 16 bytes for SOCK_STREAMS.

 */

struct sk_buff *dn_alloc_send_skb(struct sock *sk, int *size, int noblock, int *err)

{

        int space;

        int len;

        struct sk_buff *skb = NULL;

        *err = 0;

        while(skb == NULL) {

                if (signal_pending(current)) {

                        *err = ERESTARTSYS;

                        break;

                }

                if (sk->shutdown & SEND_SHUTDOWN) {

                        *err = EINVAL;

                        break;

                }

                if (sk->err)

                        break;

                len = *size + 11;

                space = sk->sndbuf - atomic_read(&sk->wmem_alloc);

                if (space < len) {

                        if ((sk->socket->type == SOCK_STREAM) && (space >= (16 + 11)))

                                len = space;

                }

                if (space < len) {

                        set_bit(SOCK_ASYNC_NOSPACE, &sk->socket->flags);

                        if (noblock) {

                                *err = EWOULDBLOCK;

                                break;

                        }

                        clear_bit(SOCK_ASYNC_WAITDATA, &sk->socket->flags);

                        SOCK_SLEEP_PRE(sk)

                        if ((sk->sndbuf - atomic_read(&sk->wmem_alloc)) < len)

                                schedule();

                        SOCK_SLEEP_POST(sk)

                        continue;

                }

                if ((skb = dn_alloc_skb(sk, len, sk->allocation)) == NULL)

                        continue;

                *size = len - 11;

        }

        return skb;

}

/*

 * Calculate persist timer based upon the smoothed round

 * trip time and the variance. Backoff according to the

 * nsp_backoff[] array.

 */

unsigned long dn_nsp_persist(struct sock *sk)

{

        struct dn_scp *scp = DN_SK(sk);

        unsigned long t = ((scp->nsp_srtt >> 2) + scp->nsp_rttvar) >> 1;

        t *= nsp_backoff[scp->nsp_rxtshift];

        if (t < HZ) t = HZ;

        if (t > (600*HZ)) t = (600*HZ);

        if (scp->nsp_rxtshift < NSP_MAXRXTSHIFT)

                scp->nsp_rxtshift++;

        /* printk(KERN_DEBUG "rxtshift %lu, t=%lu\n", scp->nsp_rxtshift, t); */

        return t;

}

/*

 * This is called each time we get an estimate for the rtt

 * on the link.

 */

static void dn_nsp_rtt(struct sock *sk, long rtt)

{

        struct dn_scp *scp = DN_SK(sk);

        long srtt = (long)scp->nsp_srtt;

        long rttvar = (long)scp->nsp_rttvar;

        long delta;

        /*

         * If the jiffies clock flips over in the middle of timestamp

         * gathering this value might turn out negative, so we make sure

         * that is it always positive here.

         */

        if (rtt < 0)

                rtt = -rtt;

        /*

         * Add new rtt to smoothed average

         */

        delta = ((rtt << 3) - srtt);

        srtt += (delta >> 3);

        if (srtt >= 1)

                scp->nsp_srtt = (unsigned long)srtt;

        else

                scp->nsp_srtt = 1;

        /*

         * Add new rtt varience to smoothed varience

         */

        delta >>= 1;

        rttvar += ((((delta>0)?(delta):(-delta)) - rttvar) >> 2);

        if (rttvar >= 1)

                scp->nsp_rttvar = (unsigned long)rttvar;

        else

                scp->nsp_rttvar = 1;

        /* printk(KERN_DEBUG "srtt=%lu rttvar=%lu\n", scp->nsp_srtt, scp->nsp_rttvar); */

}

/**

 * dn_nsp_clone_and_send - Send a data packet by cloning it

 * @skb: The packet to clone and transmit

 * @gfp: memory allocation flag

 *

 * Clone a queued data or other data packet and transmit it.

 *

 * Returns: The number of times the packet has been sent previously

 */

static inline unsigned dn_nsp_clone_and_send(struct sk_buff *skb, int gfp)

{

        struct dn_skb_cb *cb = DN_SKB_CB(skb);

        struct sk_buff *skb2;

        int ret = 0;

        if ((skb2 = skb_clone(skb, gfp)) != NULL) {

                ret = cb->xmit_count;

                cb->xmit_count++;

                cb->stamp = jiffies;

                skb2->sk = skb->sk;

                dn_nsp_send(skb2);

        }

        return ret;

}

/**

 * dn_nsp_output - Try and send something from socket queues

 * @sk: The socket whose queues are to be investigated

 * @gfp: The memory allocation flags

 *

 * Try and send the packet on the end of the data and other data queues.

 * Other data gets priority over data, and if we retransmit a packet we

 * reduce the window by dividing it in two.

 *

 */

void dn_nsp_output(struct sock *sk)

{

        struct dn_scp *scp = DN_SK(sk);

        struct sk_buff *skb;

        unsigned reduce_win = 0;

        /*

         * First we check for otherdata/linkservice messages

         */

        if ((skb = skb_peek(&scp->other_xmit_queue)) != NULL)

                reduce_win = dn_nsp_clone_and_send(skb, GFP_ATOMIC);

        /*

         * If we may not send any data, we don't.

         * If we are still trying to get some other data down the

         * channel, we don't try and send any data.

         */

        if (reduce_win || (scp->flowrem_sw != DN_SEND))

                goto recalc_window;

        if ((skb = skb_peek(&scp->data_xmit_queue)) != NULL)

                reduce_win = dn_nsp_clone_and_send(skb, GFP_ATOMIC);

        /*

         * If we've sent any frame more than once, we cut the

         * send window size in half. There is always a minimum

         * window size of one available.

         */

recalc_window:

        if (reduce_win) {

                scp->snd_window >>= 1;

                if (scp->snd_window < NSP_MIN_WINDOW)

                        scp->snd_window = NSP_MIN_WINDOW;

        }

}

int dn_nsp_xmit_timeout(struct sock *sk)

{

        struct dn_scp *scp = DN_SK(sk);

        dn_nsp_output(sk);

        if (skb_queue_len(&scp->data_xmit_queue) || skb_queue_len(&scp->other_xmit_queue))

                scp->persist = dn_nsp_persist(sk);

        return 0;

}

static inline unsigned char *dn_mk_common_header(struct dn_scp *scp, struct sk_buff *skb, unsigned char msgflag, int len)

{

        unsigned char *ptr = skb_push(skb, len);

        if (len < 5)

                BUG();

        *ptr++ = msgflag;

        *((unsigned short *)ptr) = scp->addrrem;

        ptr += 2;

        *((unsigned short *)ptr) = scp->addrloc;

        ptr += 2;

        return ptr;

}

static unsigned short *dn_mk_ack_header(struct sock *sk, struct sk_buff *skb, unsigned char msgflag, int hlen, int other)

{

        struct dn_scp *scp = DN_SK(sk);

        unsigned short acknum = scp->numdat_rcv & 0x0FFF;

        unsigned short ackcrs = scp->numoth_rcv & 0x0FFF;

        unsigned short *ptr;

        if (hlen < 9)

                BUG();

        scp->ackxmt_dat = acknum;

        scp->ackxmt_oth = ackcrs;

        acknum |= 0x8000;

        ackcrs |= 0x8000;

        /* If this is an "other data/ack" message, swap acknum and ackcrs */

        if (other) {

                unsigned short tmp = acknum;

                acknum = ackcrs;

                ackcrs = tmp;

        }

        /* Set "cross subchannel" bit in ackcrs */

        ackcrs |= 0x2000;

        ptr = (unsigned short *)dn_mk_common_header(scp, skb, msgflag, hlen);

        *ptr++ = dn_htons(acknum);

        *ptr++ = dn_htons(ackcrs);

        return ptr;

}

void dn_nsp_queue_xmit(struct sock *sk, struct sk_buff *skb, int gfp, int oth)

{

        struct dn_scp *scp = DN_SK(sk);

        struct dn_skb_cb *cb = DN_SKB_CB(skb);

        unsigned long t = ((scp->nsp_srtt >> 2) + scp->nsp_rttvar) >> 1;

        /*

         * Slow start: If we have been idle for more than

         * one RTT, then reset window to min size.

         */

        if ((jiffies - scp->stamp) > t)

                scp->snd_window = NSP_MIN_WINDOW;

        /* printk(KERN_DEBUG "Window: %lu\n", scp->snd_window); */

        cb->xmit_count = 0;

        if (oth)

                skb_queue_tail(&scp->other_xmit_queue, skb);

        else

                skb_queue_tail(&scp->data_xmit_queue, skb);

        if (scp->flowrem_sw != DN_SEND)

                return;

        dn_nsp_clone_and_send(skb, gfp);

}

int dn_nsp_check_xmit_queue(struct sock *sk, struct sk_buff *skb, struct sk_buff_head *q, unsigned short acknum)

{

        struct dn_skb_cb *cb = DN_SKB_CB(skb);

        struct dn_scp *scp = DN_SK(sk);

        struct sk_buff *skb2, *list, *ack = NULL;

        int wakeup = 0;

        int try_retrans = 0;

        unsigned long reftime = cb->stamp;

        unsigned long pkttime;

        unsigned short xmit_count;

        unsigned short segnum;

        skb2 = q->next;

        list = (struct sk_buff *)q;

        while(list != skb2) {

                struct dn_skb_cb *cb2 = DN_SKB_CB(skb2);

                if (before_or_equal(cb2->segnum, acknum))

                        ack = skb2;

                /* printk(KERN_DEBUG "ack: %s %04x %04x\n", ack ? "ACK" : "SKIP", (int)cb2->segnum, (int)acknum); */

                skb2 = skb2->next;

                if (ack == NULL)

                        continue;

                /* printk(KERN_DEBUG "check_xmit_queue: %04x, %d\n", acknum, cb2->xmit_count); */

                /* Does _last_ packet acked have xmit_count > 1 */

                try_retrans = 0;

                /* Remember to wake up the sending process */

                wakeup = 1;

                /* Keep various statistics */

                pkttime = cb2->stamp;

                xmit_count = cb2->xmit_count;

                segnum = cb2->segnum;

                /* Remove and drop ack'ed packet */

                skb_unlink(ack);

                kfree_skb(ack);

                ack = NULL;

                /*

                 * We don't expect to see acknowledgements for packets we

                 * haven't sent yet.

                 */

                if (xmit_count == 0)

                        BUG();

                /*

                 * If the packet has only been sent once, we can use it

                 * to calculate the RTT and also open the window a little

                 * further.

                 */

                if (xmit_count == 1) {

                        if (equal(segnum, acknum))

                                dn_nsp_rtt(sk, (long)(pkttime - reftime));

                        if (scp->snd_window < scp->max_window)

                                scp->snd_window++;

                }

                /*

                 * Packet has been sent more than once. If this is the last

                 * packet to be acknowledged then we want to send the next

                 * packet in the send queue again (assumes the remote host does

                 * go-back-N error control).

                 */

                if (xmit_count > 1)

                        try_retrans = 1;

        }

        if (try_retrans)

                dn_nsp_output(sk);

        return wakeup;

}

void dn_nsp_send_data_ack(struct sock *sk)

{

        struct sk_buff *skb = NULL;

        if ((skb = dn_alloc_skb(sk, 9, GFP_ATOMIC)) == NULL)

                return;

        skb_reserve(skb, 9);

        dn_mk_ack_header(sk, skb, 0x04, 9, 0);

        dn_nsp_send(skb);

}

void dn_nsp_send_oth_ack(struct sock *sk)

{

        struct sk_buff *skb = NULL;

        if ((skb = dn_alloc_skb(sk, 9, GFP_ATOMIC)) == NULL)

                return;

        skb_reserve(skb, 9);

        dn_mk_ack_header(sk, skb, 0x14, 9, 1);

        dn_nsp_send(skb);

}

void dn_send_conn_ack (struct sock *sk)

{

        struct dn_scp *scp = DN_SK(sk);

        struct sk_buff *skb = NULL;

        struct nsp_conn_ack_msg *msg;

        if ((skb = dn_alloc_skb(sk, 3, sk->allocation)) == NULL)

                return;

        msg = (struct nsp_conn_ack_msg *)skb_put(skb, 3);

        msg->msgflg = 0x24;

        msg->dstaddr = scp->addrrem;

        dn_nsp_send(skb);

}

void dn_nsp_delayed_ack(struct sock *sk)

{

        struct dn_scp *scp = DN_SK(sk);

        if (scp->ackxmt_oth != scp->numoth_rcv)

                dn_nsp_send_oth_ack(sk);

        if (scp->ackxmt_dat != scp->numdat_rcv)

                dn_nsp_send_data_ack(sk);

}

static int dn_nsp_retrans_conn_conf(struct sock *sk)

{

        struct dn_scp *scp = DN_SK(sk);

        if (scp->state == DN_CC)

                dn_send_conn_conf(sk, GFP_ATOMIC);

        return 0;

}

void dn_send_conn_conf(struct sock *sk, int gfp)

{

        struct dn_scp *scp = DN_SK(sk);

        struct sk_buff *skb = NULL;

        struct nsp_conn_init_msg *msg;

        unsigned char len = scp->conndata_out.opt_optl;

        if ((skb = dn_alloc_skb(sk, 50 + scp->conndata_out.opt_optl, gfp)) == NULL)

                return;

        msg = (struct nsp_conn_init_msg *)skb_put(skb, sizeof(*msg));

        msg->msgflg = 0x28;

        msg->dstaddr = scp->addrrem;

        msg->srcaddr = scp->addrloc;

        msg->services = scp->services_loc;

        msg->info = scp->info_loc;

        msg->segsize = dn_htons(scp->segsize_loc);

        *skb_put(skb,1) = len;

        if (len > 0)

                memcpy(skb_put(skb, len), scp->conndata_out.opt_data, len);

        dn_nsp_send(skb);

        scp->persist = dn_nsp_persist(sk);

        scp->persist_fxn = dn_nsp_retrans_conn_conf;

}

static __inline__ void dn_nsp_do_disc(struct sock *sk, unsigned char msgflg,

                        unsigned short reason, int gfp, struct dst_entry *dst,

                        int ddl, unsigned char *dd, __u16 rem, __u16 loc)

{

        struct sk_buff *skb = NULL;

        int size = 7 + ddl + ((msgflg == NSP_DISCINIT) ? 1 : 0);

        unsigned char *msg;

        if ((dst == NULL) || (rem == 0)) {

                if (net_ratelimit())

                        printk(KERN_DEBUG "DECnet: dn_nsp_do_disc: BUG! Please report this to SteveW@ACM.org rem=%u dst=%p\n", (unsigned)rem, dst);

                return;

        }

        if ((skb = dn_alloc_skb(sk, size, gfp)) == NULL)

                return;

        msg = skb_put(skb, size);

        *msg++ = msgflg;

        *(__u16 *)msg = rem;

        msg += 2;

        *(__u16 *)msg = loc;

        msg += 2;

        *(__u16 *)msg = dn_htons(reason);

        msg += 2;

        if (msgflg == NSP_DISCINIT)

                *msg++ = ddl;

        if (ddl) {

                memcpy(msg, dd, ddl);

        }

        /*

         * This doesn't go via the dn_nsp_send() fucntion since we need

         * to be able to send disc packets out which have no socket

         * associations.

         */

        skb->dst = dst_clone(dst);

        skb->dst->output(skb);

}

void dn_nsp_send_disc(struct sock *sk, unsigned char msgflg,

                        unsigned short reason, int gfp)

{

        struct dn_scp *scp = DN_SK(sk);

        int ddl = 0;

        if (msgflg == NSP_DISCINIT)

                ddl = scp->discdata_out.opt_optl;

        if (reason == 0)

                reason = scp->discdata_out.opt_status;

        dn_nsp_do_disc(sk, msgflg, reason, gfp, sk->dst_cache, ddl,

                scp->discdata_out.opt_data, scp->addrrem, scp->addrloc);

}

void dn_nsp_return_disc(struct sk_buff *skb, unsigned char msgflg,

                        unsigned short reason)

{

        struct dn_skb_cb *cb = DN_SKB_CB(skb);

        int ddl = 0;

        int gfp = GFP_ATOMIC;

        dn_nsp_do_disc(NULL, msgflg, reason, gfp, skb->dst, ddl,

                        NULL, cb->src_port, cb->dst_port);

}

void dn_nsp_send_link(struct sock *sk, unsigned char lsflags, char fcval)

{

        struct dn_scp *scp = DN_SK(sk);

        struct sk_buff *skb;

        unsigned short *segnum;

        unsigned char *ptr;

        int gfp = GFP_ATOMIC;

        if ((skb = dn_alloc_skb(sk, 13, gfp)) == NULL)

                return;

        skb_reserve(skb, 13);

        segnum = dn_mk_ack_header(sk, skb, 0x10, 13, 1);

        *segnum = dn_htons(scp->numoth);

        DN_SKB_CB(skb)->segnum = scp->numoth;

        seq_add(&scp->numoth, 1);

        ptr = (unsigned char *)(segnum + 1);

        *ptr++ = lsflags;

        *ptr = fcval;

        dn_nsp_queue_xmit(sk, skb, gfp, 1);

        scp->persist = dn_nsp_persist(sk);

        scp->persist_fxn = dn_nsp_xmit_timeout;

}

static int dn_nsp_retrans_conninit(struct sock *sk)

{

        struct dn_scp *scp = DN_SK(sk);

        if (scp->state == DN_CI)

                dn_nsp_send_conninit(sk, NSP_RCI);

        return 0;

}

void dn_nsp_send_conninit(struct sock *sk, unsigned char msgflg)

{

        struct dn_scp *scp = DN_SK(sk);

        struct sk_buff *skb = NULL;

        struct nsp_conn_init_msg *msg;

        unsigned char aux;

        unsigned char menuver;

        struct dn_skb_cb *cb;