/*
* 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 (Input)
*
* 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: Add changes from Eduardo Serrat's patches.
* Steve Whitehouse: Put all ack handling code in a common routine.
* Steve Whitehouse: Put other common bits into dn_nsp_rx()
* Steve Whitehouse: More checks on skb->len to catch bogus packets
* Fixed various race conditions and possible nasties.
* Steve Whitehouse: Now handles returned conninit frames.
* David S. Miller: New socket locking
* Steve Whitehouse: Fixed lockup when socket filtering was enabled.
* Paul Koning: Fix to push CC sockets into RUN when acks are
* received.
* Steve Whitehouse:
* Patrick Caulfield: Checking conninits for correctness & sending of error
* responses.
* Steve Whitehouse: Added backlog congestion level return codes.
* Patrick Caulfield:
* Steve Whitehouse: Added flow control support (outbound)
* Steve Whitehouse: Prepare for nonlinear skbs
*/
/******************************************************************************
(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 <net/tcp_states.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/netfilter_decnet.h>
#include <net/neighbour.h>
#include <net/dst.h>
#include <net/dn.h>
#include <net/dn_nsp.h>
#include <net/dn_dev.h>
#include <net/dn_route.h>
extern int decnet_log_martians;
static void dn_log_martian(struct sk_buff *skb, const char *msg)
{
if (decnet_log_martians && net_ratelimit()) {
char *devname = skb->dev ? skb->dev->name : "???";
struct dn_skb_cb *cb = DN_SKB_CB(skb);
printk(KERN_INFO "DECnet: Martian packet (%s) dev=%s src=0x%04hx dst=0x%04hx srcport=0x%04hx dstport=0x%04hx\n", msg, devname, dn_ntohs(cb->src), dn_ntohs(cb->dst), dn_ntohs(cb->src_port), dn_ntohs(cb->dst_port));
}
}
/*
* For this function we've flipped the cross-subchannel bit
* if the message is an otherdata or linkservice message. Thus
* we can use it to work out what to update.
*/
static void dn_ack(struct sock *sk, struct sk_buff *skb, unsigned short ack)
{
struct dn_scp *scp = DN_SK(sk);
unsigned short type = ((ack >> 12) & 0x0003);
int wakeup = 0;
switch(type) {
case 0: /* ACK - Data */
if (dn_after(ack, scp->ackrcv_dat)) {
scp->ackrcv_dat = ack & 0x0fff;
wakeup |= dn_nsp_check_xmit_queue(sk, skb, &scp->data_xmit_queue, ack);
}
break;
case 1: /* NAK - Data */
break;
case 2: /* ACK - OtherData */
if (dn_after(ack, scp->ackrcv_oth)) {
scp->ackrcv_oth = ack & 0x0fff;
wakeup |= dn_nsp_check_xmit_queue(sk, skb, &scp->other_xmit_queue, ack);
}
break;
case 3: /* NAK - OtherData */
break;
}
if (wakeup && !sock_flag(sk, SOCK_DEAD))
sk->sk_state_change(sk);
}
/*
* This function is a universal ack processor.
*/
static int dn_process_ack(struct sock *sk, struct sk_buff *skb, int oth)
{
__le16 *ptr = (__le16 *)skb->data;
int len = 0;
unsigned short ack;
if (skb->len < 2)
return len;
if ((ack = dn_ntohs(*ptr)) & 0x8000) {
skb_pull(skb, 2);
ptr++;
len += 2;
if ((ack & 0x4000) == 0) {
if (oth)
ack ^= 0x2000;
dn_ack(sk, skb, ack);
}
}
if (skb->len < 2)
return len;
if ((ack = dn_ntohs(*ptr)) & 0x8000) {
skb_pull(skb, 2);
len += 2;
if ((ack & 0x4000) == 0) {
if (oth)
ack ^= 0x2000;
dn_ack(sk, skb, ack);
}
}
return len;
}
/**
* dn_check_idf - Check an image data field format is correct.
* @pptr: Pointer to pointer to image data
* @len: Pointer to length of image data
* @max: The maximum allowed length of the data in the image data field
* @follow_on: Check that this many bytes exist beyond the end of the image data
*
* Returns: 0 if ok, -1 on error
*/
static inline int dn_check_idf(unsigned char **pptr, int *len, unsigned char max, unsigned char follow_on)
{
unsigned char *ptr = *pptr;
unsigned char flen = *ptr++;
(*len)--;
if (flen > max)
return -1;
if ((flen + follow_on) > *len)
return -1;
*len -= flen;
*pptr = ptr + flen;
return 0;
}
/*
* Table of reason codes to pass back to node which sent us a badly
* formed message, plus text messages for the log. A zero entry in
* the reason field means "don't reply" otherwise a disc init is sent with
* the specified reason code.
*/
static struct {
unsigned short reason;
const char *text;
} ci_err_table[] = {
{ 0, "CI: Truncated message" },
{ NSP_REASON_ID, "CI: Destination username error" },
{ NSP_REASON_ID, "CI: Destination username type" },
{ NSP_REASON_US, "CI: Source username error" },
{ 0, "CI: Truncated at menuver" },
{ 0, "CI: Truncated before access or user data" },
{ NSP_REASON_IO, "CI: Access data format error" },
{ NSP_REASON_IO, "CI: User data format error" }
};
/*
* This function uses a slightly different lookup method
* to find its sockets, since it searches on object name/number
* rather than port numbers. Various tests are done to ensure that
* the incoming data is in the correct format before it is queued to
* a socket.
*/
static struct sock *dn_find_listener(struct sk_buff *skb, unsigned short *reason)
{
struct dn_skb_cb *cb = DN_SKB_CB(skb);
struct nsp_conn_init_msg *msg = (struct nsp_conn_init_msg *)skb->data;
struct sockaddr_dn dstaddr;
struct sockaddr_dn srcaddr;
unsigned char type = 0;
int dstlen;
int srclen;
unsigned char *ptr;
int len;
int err = 0;
unsigned char menuver;
memset(&dstaddr, 0, sizeof(struct sockaddr_dn));
memset(&srcaddr, 0, sizeof(struct sockaddr_dn));
/*
* 1. Decode & remove message header
*/
cb->src_port = msg->srcaddr;
cb->dst_port = msg->dstaddr;
cb->services = msg->services;
cb->info = msg->info;
cb->segsize = dn_ntohs(msg->segsize);
if (!pskb_may_pull(skb, sizeof(*msg)))
goto err_out;
skb_pull(skb, sizeof(*msg));
len = skb->len;
ptr = skb->data;
/*
* 2. Check destination end username format
*/
dstlen = dn_username2sockaddr(ptr, len, &dstaddr, &type);
err++;
if (dstlen < 0)
goto err_out;
err++;
if (type > 1)
goto err_out;
len -= dstlen;
ptr += dstlen;
/*
* 3. Check source end username format
*/
srclen = dn_username2sockaddr(ptr, len, &srcaddr, &type);
err++;
if (srclen < 0)
goto err_out;
len -= srclen;
ptr += srclen;
err++;
if (len < 1)
goto err_out;
menuver = *ptr;
ptr++;
len--;
/*
* 4. Check that optional data actually exists if menuver says it does
*/
err++;
if ((menuver & (DN_MENUVER_ACC | DN_MENUVER_USR)) && (len < 1))
goto err_out;
/*
* 5. Check optional access data format
*/
err++;
if (menuver & DN_MENUVER_ACC) {
if (dn_check_idf(&ptr, &len, 39, 1))
goto err_out;
if (dn_check_idf(&ptr, &len, 39, 1))
goto err_out;
if (dn_check_idf(&ptr, &len, 39, (menuver & DN_MENUVER_USR) ? 1 : 0))
goto err_out;
}
/*
* 6. Check optional user data format
*/
err++;
if (menuver & DN_MENUVER_USR) {
if (dn_check_idf(&ptr, &len, 16, 0))
goto err_out;
}
/*
* 7. Look up socket based on destination end username
*/
return dn_sklist_find_listener(&dstaddr);
err_out:
dn_log_martian(skb, ci_err_table[err].text);
*reason = ci_err_table[err].reason;
return NULL;
}
static void dn_nsp_conn_init(struct sock *sk, struct sk_buff *skb)
{
if (sk_acceptq_is_full(sk)) {
kfree_skb(skb);
return;
}
sk->sk_ack_backlog++;
skb_queue_tail(&sk->sk_receive_queue, skb);
sk->sk_state_change(sk);
}
static void dn_nsp_conn_conf(struct sock *sk, struct sk_buff *skb)
{
struct dn_skb_cb *cb = DN_SKB_CB(skb);
struct dn_scp *scp = DN_SK(sk);
unsigned char *ptr;
if (skb->len < 4)
goto out;
ptr = skb->data;
cb->services = *ptr++;
cb->info = *ptr++;
cb->segsize = dn_ntohs(*(__le16 *)ptr);
if ((scp->state == DN_CI) || (scp->state == DN_CD)) {
scp->persist = 0;
scp->addrrem = cb->src_port;
sk->sk_state = TCP_ESTABLISHED;
scp->state = DN_RUN;
scp->services_rem = cb->services;
scp->info_rem = cb->info;
scp->segsize_rem = cb->segsize;
if ((scp->services_rem & NSP_FC_MASK) == NSP_FC_NONE)
scp->max_window = decnet_no_fc_max_cwnd;
if (skb->len > 0) {
unsigned char dlen = *skb->data;
if ((dlen <= 16) && (dlen <= skb->len)) {
scp->conndata_in.opt_optl = dn_htons((__u16)dlen);
memcpy(scp->conndata_in.opt_data, skb->data + 1, dlen);
}
}
dn_nsp_send_link(sk, DN_NOCHANGE, 0);
if (!sock_flag(sk, SOCK_DEAD))
sk->sk_state_change(sk);
}
out:
kfree_skb(skb);
}
static void dn_nsp_conn_ack(struct sock *sk, struct sk_buff *skb)
{
struct dn_scp *scp = DN_SK(sk);
if (scp->state == DN_CI) {
scp->state = DN_CD;
scp->persist = 0;
}
kfree_skb(skb);
}
static void dn_nsp_disc_init(struct sock *sk, struct sk_buff *skb)
{
struct dn_scp *scp = DN_SK(sk);
struct dn_skb_cb *cb = DN_SKB_CB(skb);
unsigned short reason;
if (skb->len < 2)
goto out;
reason = dn_ntohs(*(__le16 *)skb->data);
skb_pull(skb, 2);
scp->discdata_in.opt_status = dn_htons(reason);
scp->discdata_in.opt_optl = 0;
memset(scp->discdata_in.opt_data, 0, 16);
if (skb->len > 0) {
unsigned char dlen = *skb->data;
if ((dlen <= 16) && (dlen <= skb->len)) {
scp->discdata_in.opt_optl = dn_htons((__u16)dlen);
memcpy(scp->discdata_in.opt_data, skb->data + 1, dlen);
}
}
scp->addrrem = cb->src_port;
sk->sk_state = TCP_CLOSE;
switch(scp->state) {
case DN_CI:
case DN_CD:
scp->state = DN_RJ;
sk->sk_err = ECONNREFUSED;
break;
case DN_RUN:
sk->sk_shutdown |= SHUTDOWN_MASK;
scp->state = DN_DN;
break;
case DN_DI:
scp->state = DN_DIC;
break;
}
if (!sock_flag(sk, SOCK_DEAD)) {
if (sk->sk_socket->state != SS_UNCONNECTED)
sk->sk_socket->state = SS_DISCONNECTING;
sk->sk_state_change(sk);
}
/*
* It appears that its possible for remote machines to send disc
* init messages with no port identifier if we are in the CI and
* possibly also the CD state. Obviously we shouldn't reply with
* a message if we don't know what the end point is.
*/
if (scp->addrrem) {
dn_nsp_send_disc(sk, NSP_DISCCONF, NSP_REASON_DC, GFP_ATOMIC);
}
scp->persist_fxn = dn_destroy_timer;
scp->persist = dn_nsp_persist(sk);
out:
kfree_skb(skb);
}
/*
* disc_conf messages are also called no_resources or no_link
* messages depending upon the "reason" field.
*/
static void dn_nsp_disc_conf(struct sock *sk, struct sk_buff *skb)
{
struct dn_scp *scp = DN_SK(sk);
unsigned short reason;
if (skb->len != 2)
goto out;
reason = dn_ntohs(*(__le16 *)skb->data);
sk->sk_state = TCP_CLOSE;
switch(scp->state) {
case DN_CI:
scp->state = DN_NR;
break;
case DN_DR:
if (reason == NSP_REASON_DC)
scp->state = DN_DRC;
if (reason == NSP_REASON_NL)
scp->state = DN_CN;
break;
case DN_DI:
scp->state = DN_DIC;
break;
case DN_RUN:
sk->sk_shutdown |= SHUTDOWN_MASK;
case DN_CC:
scp->state = DN_CN;
}
if (!sock_flag(sk, SOCK_DEAD)) {
if (sk->sk_socket->state != SS_UNCONNECTED)
sk->sk_socket->state = SS_DISCONNECTING;
sk->sk_state_change(sk);
}
scp->persist_fxn = dn_destroy_timer;
scp->persist = dn_nsp_persist(sk);
out:
kfree_skb(skb);
}
static void dn_nsp_linkservice(struct sock *sk, struct sk_buff *skb)
{
struct dn_scp *scp = DN_SK(sk);
unsigned short segnum;
unsigned char lsflags;
signed char fcval;
int wake_up = 0;
char *ptr = skb->data;
unsigned char fctype = scp->services_rem & NSP_FC_MASK;
if (skb->len != 4)
goto out;
segnum = dn_ntohs(*(__le16 *)ptr);
ptr += 2;
lsflags = *(unsigned char *)ptr++;
fcval = *ptr;
/*
* Here we ignore erronous packets which should really
* should cause a connection abort. It is not critical
* for now though.
*/
if (lsflags & 0xf8)
goto out;
if (seq_next(scp->numoth_rcv, segnum)) {
seq_add(&scp->numoth_rcv, 1);
switch(lsflags & 0x04) { /* FCVAL INT */
case 0x00: /* Normal Request */
switch(lsflags & 0x03) { /* FCVAL MOD */
case 0x00: /* Request count */
if (fcval < 0) {
unsigned char p_fcval = -fcval;
if ((scp->flowrem_dat > p_fcval) &&
(fctype == NSP_FC_SCMC)) {
scp->flowrem_dat -= p_fcval;
}
} else if (fcval > 0) {
scp->flowrem_dat += fcval;
wake_up = 1;
}
break;
case 0x01: /* Stop outgoing data */
scp->flowrem_sw = DN_DONTSEND;
break;
case 0x02: /* Ok to start again */
scp->flowrem_sw = DN_SEND;
dn_nsp_output(sk);
wake_up = 1;
}
break;
case 0x04: /* Interrupt Request */
if (fcval > 0) {
scp->flowrem_oth += fcval;
wake_up = 1;
}
break;
}
if (wake_up && !sock_flag(sk, SOCK_DEAD))
sk->sk_state_change(sk);
}
dn_nsp_send_oth_ack(sk);
out:
kfree_skb(skb);
}
/*
* Copy of sock_queue_rcv_skb (from sock.h) without
* bh_lock_sock() (its already held when this is called) which
* also allows data and other data to be queued to a socket.
*/
static __inline__ int dn_queue_skb(struct sock *sk, struct sk_buff *skb, int sig, struct sk_buff_head *queue)
{
int err;
/* Cast skb->rcvbuf to unsigned... It's pointless, but reduces
number of warnings when compiling with -W --ANK
*/
if (atomic_read(&sk->sk_rmem_alloc) + skb->truesize >=
(unsigned)sk->sk_rcvbuf) {
err = -ENOMEM;
goto out;
}
err = sk_filter(sk, skb);
if (err)
goto out;
skb_set_owner_r(skb, sk);
skb_queue_tail(queue, skb);
/* This code only runs from BH or BH protected context.
* Therefore the plain read_lock is ok here. -DaveM
*/
read_lock(&sk->sk_callback_lock);
if (!sock_flag(sk, SOCK_DEAD)) {
struct socket *sock = sk->sk_socket;
wake_up_interruptible(sk->sk_sleep);
if (sock && sock->fasync_list &&
!test_bit(SOCK_ASYNC_WAITDATA, &sock->flags))
__kill_fasync(sock->fasync_list, sig,
(sig == SIGURG) ? POLL_PRI : POLL_IN);
}
read_unlock(&sk->sk_callback_lock);
out:
return err;
}
static void dn_nsp_otherdata(struct sock *sk, struct sk_buff *skb)
{
struct dn_scp *scp = DN_SK(sk);
unsigned short segnum;
struct dn_skb_cb *cb = DN_SKB_CB(skb);
int queued = 0;
if (skb->len < 2)
goto out;
cb->segnum = segnum = dn_ntohs(*(__le16 *)skb->data);
skb_pull(skb, 2);
if (seq_next(scp->numoth_rcv, segnum)) {
if (dn_queue_skb(sk, skb, SIGURG, &scp->other_receive_queue) == 0) {
seq_add(&scp->numoth_rcv, 1);
scp->other_report = 0;
queued = 1;
}
}
dn_nsp_send_oth_ack(sk);
out:
if (!queued)
kfree_skb(skb);
}
static void dn_nsp_data(struct sock *sk, struct sk_buff *skb)
{
int queued = 0;
unsigned short segnum;
struct dn_skb_cb *cb = DN_SKB_CB(skb);
struct dn_scp *scp = DN_SK(sk);
if (skb->len < 2)
goto out;
cb->segnum = segnum = dn_ntohs(*(__le16 *)skb->data);
skb_pull(skb, 2);
if (seq_next(scp->numdat_rcv, segnum)) {
if (dn_queue_skb(sk, skb, SIGIO, &sk->sk_receive_queue) == 0) {
seq_add(&scp->numdat_rcv, 1);
queued = 1;
}
if ((scp->flowloc_sw == DN_SEND) && dn_congested(sk)) {
scp->flowloc_sw = DN_DONTSEND;
dn_nsp_send_link(sk, DN_DONTSEND, 0);
}
}
dn_nsp_send_data_ack(sk);
out:
if (!queued)
kfree_skb(skb);
}
/*
* If one of our conninit messages is returned, this function
* deals with it. It puts the socket into the NO_COMMUNICATION
* state.
*/
static void dn_returned_conn_init(struct sock *sk, struct sk_buff *skb)
{
struct dn_scp *scp = DN_SK(sk);
if (scp->state == DN_CI) {
scp->state = DN_NC;
sk->sk_state = TCP_CLOSE;
if (!sock_flag(sk, SOCK_DEAD))
sk->sk_state_change(sk);
}
kfree_skb(skb);
}
static int dn_nsp_no_socket(struct sk_buff *skb, unsigned short reason)
{
struct dn_skb_cb *cb = DN_SKB_CB(skb);
int ret = NET_RX_DROP;
/* Must not reply to returned packets */
if (cb->rt_flags & DN_RT_F_RTS)
goto out;
if ((reason != NSP_REASON_OK) && ((cb->nsp_flags & 0x0c) == 0x08)) {
switch(cb->nsp_flags & 0x70) {
case 0x10:
case 0x60: /* (Retransmitted) Connect Init */
dn_nsp_return_disc(skb, NSP_DISCINIT, reason);
ret = NET_RX_SUCCESS;
break;
case 0x20: /* Connect Confirm */
dn_nsp_return_disc(skb, NSP_DISCCONF, reason);
ret = NET_RX_SUCCESS;
break;
}
}
out:
kfree_skb(skb);
return ret;
}
static int dn_nsp_rx_packet(struct sk_buff *skb)
{
struct dn_skb_cb *cb = DN_SKB_CB(skb);
struct sock *sk = NULL;
unsigned char *ptr = (unsigned char *)skb->data;
unsigned short reason = NSP_REASON_NL;
if (!pskb_may_pull(skb, 2))
goto free_out;
skb->h.raw = skb->data;
cb->nsp_flags = *ptr++;
if (decnet_debug_level & 2)
printk(KERN_DEBUG "dn_nsp_rx: Message type 0x%02x\n", (int)cb->nsp_flags);
if (cb->nsp_flags & 0x83)
goto free_out;
/*
* Filter out conninits and useless packet types
*/
if ((cb->nsp_flags & 0x0c) == 0x08) {
switch(cb->nsp_flags & 0x70) {
case 0x00: /* NOP */
case 0x70: /* Reserved */
case 0x50: /* Reserved, Phase II node init */
goto free_out;
case 0x10:
case 0x60:
if (unlikely(cb->rt_flags & DN_RT_F_RTS))
goto free_out;
sk = dn_find_listener(skb, &reason);
goto got_it;
}
}
if (!pskb_may_pull(skb, 3))
goto free_out;
/*
* Grab the destination address.
*/
cb->dst_port = *(__le16 *)ptr;
cb->src_port = 0;
ptr += 2;
/*
* If not a connack, grab the source address too.
*/
if (pskb_may_pull(skb, 5)) {
cb->src_port = *(__le16 *)ptr;
ptr += 2;
skb_pull(skb, 5);
}
/*
* Returned packets...
* Swap src & dst and look up in the normal way.
*/
if (unlikely(cb->rt_flags & DN_RT_F_RTS)) {
__le16 tmp = cb->dst_port;
cb->dst_port = cb->src_port;
cb->src_port = tmp;
tmp = cb->dst;
cb->dst = cb->src;
cb->src = tmp;
}
/*
* Find the socket to which this skb is destined.
*/
sk = dn_find_by_skb(skb);
got_it:
if (sk != NULL) {
struct dn_scp *scp = DN_SK(sk);
/* Reset backoff */
scp->nsp_rxtshift = 0;
/*
* We linearize everything except data segments here.
*/
if (cb->nsp_flags & ~0x60) {
if (unlikely(skb_linearize(skb)))
goto free_out;
}
return sk_receive_skb(sk, skb);
}
return dn_nsp_no_socket(skb, reason);
free_out:
kfree_skb(skb);
return NET_RX_DROP;
}
int dn_nsp_rx(struct sk_buff *skb)
{
return NF_HOOK(PF_DECnet, NF_DN_LOCAL_IN, skb, skb->dev, NULL, dn_nsp_rx_packet);
}
/*
* This is the main receive routine for sockets. It is called
* from the above when the socket is not busy, and also from
* sock_release() when there is a backlog queued up.
*/
int dn_nsp_backlog_rcv(struct sock *sk, struct sk_buff *skb)
{
struct dn_scp *scp = DN_SK(sk);
struct dn_skb_cb *cb = DN_SKB_CB(skb);
if (cb->rt_flags & DN_RT_F_RTS) {
if (cb->nsp_flags == 0x18 || cb->nsp_flags == 0x68)
dn_returned_conn_init(sk, skb);
else
kfree_skb(skb);
return NET_RX_SUCCESS;
}
/*
* Control packet.
*/
if ((cb->nsp_flags & 0x0c) == 0x08) {
switch(cb->nsp_flags & 0x70) {
case 0x10:
case 0x60:
dn_nsp_conn_init(sk, skb);
break;
case 0x20:
dn_nsp_conn_conf(sk, skb);
break;
case 0x30:
dn_nsp_disc_init(sk, skb);
break;
case 0x40:
dn_nsp_disc_conf(sk, skb);
break;
}
} else if (cb->nsp_flags == 0x24) {
/*
* Special for connacks, 'cos they don't have
* ack data or ack otherdata info.
*/
dn_nsp_conn_ack(sk, skb);
} else {
int other = 1;
/* both data and ack frames can kick a CC socket into RUN */
if ((scp->state == DN_CC) && !sock_flag(sk, SOCK_DEAD)) {
scp->state = DN_RUN;
sk->sk_state = TCP_ESTABLISHED;
sk->sk_state_change(sk);
}
if ((cb->nsp_flags & 0x1c) == 0)
other = 0;
if (cb->nsp_flags == 0x04)
other = 0;
/*
* Read out ack data here, this applies equally
* to data, other data, link serivce and both
* ack data and ack otherdata.
*/
dn_process_ack(sk, skb, other);
/*
* If we've some sort of data here then call a
* suitable routine for dealing with it, otherwise
* the packet is an ack and can be discarded.
*/
if ((cb->nsp_flags & 0x0c) == 0) {
if (scp->state != DN_RUN)
goto free_out;
switch(cb->nsp_flags) {
case 0x10: /* LS */
dn_nsp_linkservice(sk, skb);
break;
case 0x30: /* OD */
dn_nsp_otherdata(sk, skb);
break;
default:
dn_nsp_data(sk, skb);
}
} else { /* Ack, chuck it out here */
free_out:
kfree_skb(skb);
}
}
return NET_RX_SUCCESS;
}
