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/*
* 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;
unsigned char type = 1;
if ((skb = dn_alloc_skb(sk, 200, (msgflg == NSP_CI) ? sk->allocation : GFP_ATOMIC)) == NULL)
return;
cb = DN_SKB_CB(skb);
msg = (struct nsp_conn_init_msg *)skb_put(skb,sizeof(*msg));
msg->msgflg = msgflg;
msg->dstaddr = 0x0000; /* Remote Node will assign it*/
msg->srcaddr = scp->addrloc;
msg->services = scp->services_loc; /* Requested flow control */
msg->info = scp->info_loc; /* Version Number */
msg->segsize = dn_htons(scp->segsize_loc); /* Max segment size */
if (scp->peer.sdn_objnum)
type = 0;
skb_put(skb, dn_sockaddr2username(&scp->peer, skb->tail, type));
skb_put(skb, dn_sockaddr2username(&scp->addr, skb->tail, 2));
menuver = DN_MENUVER_ACC | DN_MENUVER_USR;
if (scp->peer.sdn_flags & SDF_PROXY)
menuver |= DN_MENUVER_PRX;
if (scp->peer.sdn_flags & SDF_UICPROXY)
menuver |= DN_MENUVER_UIC;
*skb_put(skb, 1) = menuver; /* Menu Version */
aux = scp->accessdata.acc_userl;
*skb_put(skb, 1) = aux;
if (aux > 0)
memcpy(skb_put(skb, aux), scp->accessdata.acc_user, aux);
aux = scp->accessdata.acc_passl;
*skb_put(skb, 1) = aux;
if (aux > 0)
memcpy(skb_put(skb, aux), scp->accessdata.acc_pass, aux);
aux = scp->accessdata.acc_accl;
*skb_put(skb, 1) = aux;
if (aux > 0)
memcpy(skb_put(skb, aux), scp->accessdata.acc_acc, aux);
aux = scp->conndata_out.opt_optl;
*skb_put(skb, 1) = aux;
if (aux > 0)
memcpy(skb_put(skb,aux), scp->conndata_out.opt_data, aux);
scp->persist = dn_nsp_persist(sk);
scp->persist_fxn = dn_nsp_retrans_conninit;
cb->rt_flags = DN_RT_F_RQR;
dn_nsp_send(skb);
}
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