af_decnet.c

linux 内核源代码

		if (flags & MSG_OOB) {
			if (scp->flowrem_oth == 0)
				return 1;
		} else {
			if (scp->flowrem_dat == 0)
				return 1;
		}
	}
	return 0;
}

/*
 * The DECnet spec requires that the "routing layer" accepts packets which
 * are at least 230 bytes in size. This excludes any headers which the NSP
 * layer might add, so we always assume that we'll be using the maximal
 * length header on data packets. The variation in length is due to the
 * inclusion (or not) of the two 16 bit acknowledgement fields so it doesn't
 * make much practical difference.
 */
unsigned dn_mss_from_pmtu(struct net_device *dev, int mtu)
{
	unsigned mss = 230 - DN_MAX_NSP_DATA_HEADER;
	if (dev) {
		struct dn_dev *dn_db = dev->dn_ptr;
		mtu -= LL_RESERVED_SPACE(dev);
		if (dn_db->use_long)
			mtu -= 21;
		else
			mtu -= 6;
		mtu -= DN_MAX_NSP_DATA_HEADER;
	} else {
		/*
		 * 21 = long header, 16 = guess at MAC header length
		 */
		mtu -= (21 + DN_MAX_NSP_DATA_HEADER + 16);
	}
	if (mtu > mss)
		mss = mtu;
	return mss;
}

static inline unsigned int dn_current_mss(struct sock *sk, int flags)
{
	struct dst_entry *dst = __sk_dst_get(sk);
	struct dn_scp *scp = DN_SK(sk);
	int mss_now = min_t(int, scp->segsize_loc, scp->segsize_rem);

	/* Other data messages are limited to 16 bytes per packet */
	if (flags & MSG_OOB)
		return 16;

	/* This works out the maximum size of segment we can send out */
	if (dst) {
		u32 mtu = dst_mtu(dst);
		mss_now = min_t(int, dn_mss_from_pmtu(dst->dev, mtu), mss_now);
	}

	return mss_now;
}

/*
 * N.B. We get the timeout wrong here, but then we always did get it
 * wrong before and this is another step along the road to correcting
 * it. It ought to get updated each time we pass through the routine,
 * but in practise it probably doesn't matter too much for now.
 */
static inline struct sk_buff *dn_alloc_send_pskb(struct sock *sk,
			      unsigned long datalen, int noblock,
			      int *errcode)
{
	struct sk_buff *skb = sock_alloc_send_skb(sk, datalen,
						   noblock, errcode);
	if (skb) {
		skb->protocol = __constant_htons(ETH_P_DNA_RT);
		skb->pkt_type = PACKET_OUTGOING;
	}
	return skb;
}

static int dn_sendmsg(struct kiocb *iocb, struct socket *sock,
		      struct msghdr *msg, size_t size)
{
	struct sock *sk = sock->sk;
	struct dn_scp *scp = DN_SK(sk);
	size_t mss;
	struct sk_buff_head *queue = &scp->data_xmit_queue;
	int flags = msg->msg_flags;
	int err = 0;
	size_t sent = 0;
	int addr_len = msg->msg_namelen;
	struct sockaddr_dn *addr = (struct sockaddr_dn *)msg->msg_name;
	struct sk_buff *skb = NULL;
	struct dn_skb_cb *cb;
	size_t len;
	unsigned char fctype;
	long timeo;

	if (flags & ~(MSG_TRYHARD|MSG_OOB|MSG_DONTWAIT|MSG_EOR|MSG_NOSIGNAL|MSG_MORE|MSG_CMSG_COMPAT))
		return -EOPNOTSUPP;

	if (addr_len && (addr_len != sizeof(struct sockaddr_dn)))
		return -EINVAL;

	lock_sock(sk);
	timeo = sock_sndtimeo(sk, flags & MSG_DONTWAIT);
	/*
	 * The only difference between stream sockets and sequenced packet
	 * sockets is that the stream sockets always behave as if MSG_EOR
	 * has been set.
	 */
	if (sock->type == SOCK_STREAM) {
		if (flags & MSG_EOR) {
			err = -EINVAL;
			goto out;
		}
		flags |= MSG_EOR;
	}


	err = dn_check_state(sk, addr, addr_len, &timeo, flags);
	if (err)
		goto out_err;

	if (sk->sk_shutdown & SEND_SHUTDOWN) {
		err = -EPIPE;
		if (!(flags & MSG_NOSIGNAL))
			send_sig(SIGPIPE, current, 0);
		goto out_err;
	}

	if ((flags & MSG_TRYHARD) && sk->sk_dst_cache)
		dst_negative_advice(&sk->sk_dst_cache);

	mss = scp->segsize_rem;
	fctype = scp->services_rem & NSP_FC_MASK;

	mss = dn_current_mss(sk, flags);

	if (flags & MSG_OOB) {
		queue = &scp->other_xmit_queue;
		if (size > mss) {
			err = -EMSGSIZE;
			goto out;
		}
	}

	scp->persist_fxn = dn_nsp_xmit_timeout;

	while(sent < size) {
		err = sock_error(sk);
		if (err)
			goto out;

		if (signal_pending(current)) {
			err = sock_intr_errno(timeo);
			goto out;
		}

		/*
		 * Calculate size that we wish to send.
		 */
		len = size - sent;

		if (len > mss)
			len = mss;

		/*
		 * Wait for queue size to go down below the window
		 * size.
		 */
		if (dn_queue_too_long(scp, queue, flags)) {
			if (flags & MSG_DONTWAIT) {
				err = -EWOULDBLOCK;
				goto out;
			}

			SOCK_SLEEP_PRE(sk)

			if (dn_queue_too_long(scp, queue, flags))
				schedule();

			SOCK_SLEEP_POST(sk)

			continue;
		}

		/*
		 * Get a suitably sized skb.
		 * 64 is a bit of a hack really, but its larger than any
		 * link-layer headers and has served us well as a good
		 * guess as to their real length.
		 */
		skb = dn_alloc_send_pskb(sk, len + 64 + DN_MAX_NSP_DATA_HEADER,
					 flags & MSG_DONTWAIT, &err);

		if (err)
			break;

		if (!skb)
			continue;

		cb = DN_SKB_CB(skb);

		skb_reserve(skb, 64 + DN_MAX_NSP_DATA_HEADER);

		if (memcpy_fromiovec(skb_put(skb, len), msg->msg_iov, len)) {
			err = -EFAULT;
			goto out;
		}

		if (flags & MSG_OOB) {
			cb->nsp_flags = 0x30;
			if (fctype != NSP_FC_NONE)
				scp->flowrem_oth--;
		} else {
			cb->nsp_flags = 0x00;
			if (scp->seg_total == 0)
				cb->nsp_flags |= 0x20;

			scp->seg_total += len;

			if (((sent + len) == size) && (flags & MSG_EOR)) {
				cb->nsp_flags |= 0x40;
				scp->seg_total = 0;
				if (fctype == NSP_FC_SCMC)
					scp->flowrem_dat--;
			}
			if (fctype == NSP_FC_SRC)
				scp->flowrem_dat--;
		}

		sent += len;
		dn_nsp_queue_xmit(sk, skb, sk->sk_allocation, flags & MSG_OOB);
		skb = NULL;

		scp->persist = dn_nsp_persist(sk);

	}
out:

	if (skb)
		kfree_skb(skb);

	release_sock(sk);

	return sent ? sent : err;

out_err:
	err = sk_stream_error(sk, flags, err);
	release_sock(sk);
	return err;
}

static int dn_device_event(struct notifier_block *this, unsigned long event,
			void *ptr)
{
	struct net_device *dev = (struct net_device *)ptr;

	if (dev->nd_net != &init_net)
		return NOTIFY_DONE;

	switch(event) {
		case NETDEV_UP:
			dn_dev_up(dev);
			break;
		case NETDEV_DOWN:
			dn_dev_down(dev);
			break;
		default:
			break;
	}

	return NOTIFY_DONE;
}

static struct notifier_block dn_dev_notifier = {
	.notifier_call = dn_device_event,
};

extern int dn_route_rcv(struct sk_buff *, struct net_device *, struct packet_type *, struct net_device *);

static struct packet_type dn_dix_packet_type = {
	.type =		__constant_htons(ETH_P_DNA_RT),
	.dev =		NULL,		/* All devices */
	.func =		dn_route_rcv,
};

#ifdef CONFIG_PROC_FS
struct dn_iter_state {
	int bucket;
};

static struct sock *dn_socket_get_first(struct seq_file *seq)
{
	struct dn_iter_state *state = seq->private;
	struct sock *n = NULL;

	for(state->bucket = 0;
	    state->bucket < DN_SK_HASH_SIZE;
	    ++state->bucket) {
		n = sk_head(&dn_sk_hash[state->bucket]);
		if (n)
			break;
	}

	return n;
}

static struct sock *dn_socket_get_next(struct seq_file *seq,
				       struct sock *n)
{
	struct dn_iter_state *state = seq->private;

	n = sk_next(n);
try_again:
	if (n)
		goto out;
	if (++state->bucket >= DN_SK_HASH_SIZE)
		goto out;
	n = sk_head(&dn_sk_hash[state->bucket]);
	goto try_again;
out:
	return n;
}

static struct sock *socket_get_idx(struct seq_file *seq, loff_t *pos)
{
	struct sock *sk = dn_socket_get_first(seq);

	if (sk) {
		while(*pos && (sk = dn_socket_get_next(seq, sk)))
			--*pos;
	}
	return *pos ? NULL : sk;
}

static void *dn_socket_get_idx(struct seq_file *seq, loff_t pos)
{
	void *rc;
	read_lock_bh(&dn_hash_lock);
	rc = socket_get_idx(seq, &pos);
	if (!rc) {
		read_unlock_bh(&dn_hash_lock);
	}
	return rc;
}

static void *dn_socket_seq_start(struct seq_file *seq, loff_t *pos)
{
	return *pos ? dn_socket_get_idx(seq, *pos - 1) : SEQ_START_TOKEN;
}

static void *dn_socket_seq_next(struct seq_file *seq, void *v, loff_t *pos)
{
	void *rc;

	if (v == SEQ_START_TOKEN) {
		rc = dn_socket_get_idx(seq, 0);
		goto out;
	}

	rc = dn_socket_get_next(seq, v);
	if (rc)
		goto out;
	read_unlock_bh(&dn_hash_lock);
out:
	++*pos;
	return rc;
}

static void dn_socket_seq_stop(struct seq_file *seq, void *v)
{
	if (v && v != SEQ_START_TOKEN)
		read_unlock_bh(&dn_hash_lock);
}

#define IS_NOT_PRINTABLE(x) ((x) < 32 || (x) > 126)

static void dn_printable_object(struct sockaddr_dn *dn, unsigned char *buf)
{
	int i;

	switch (dn_ntohs(dn->sdn_objnamel)) {
		case 0:
			sprintf(buf, "%d", dn->sdn_objnum);
			break;
		default:
			for (i = 0; i < dn_ntohs(dn->sdn_objnamel); i++) {
				buf[i] = dn->sdn_objname[i];
				if (IS_NOT_PRINTABLE(buf[i]))
					buf[i] = '.';
			}
			buf[i] = 0;
	}
}

static char *dn_state2asc(unsigned char state)
{
	switch(state) {
		case DN_O:
			return "OPEN";
		case DN_CR:
			return "  CR";
		case DN_DR:
			return "  DR";
		case DN_DRC:
			return " DRC";
		case DN_CC:
			return "  CC";
		case DN_CI:
			return "  CI";
		case DN_NR:
			return "  NR";
		case DN_NC:
			return "  NC";
		case DN_CD:
			return "  CD";
		case DN_RJ:
			return "  RJ";
		case DN_RUN:
			return " RUN";
		case DN_DI:
			return "  DI";
		case DN_DIC:
			return " DIC";
		case DN_DN:
			return "  DN";
		case DN_CL:
			return "  CL";
		case DN_CN:
			return "  CN";
	}

	return "????";
}

static inline void dn_socket_format_entry(struct seq_file *seq, struct sock *sk)
{
	struct dn_scp *scp = DN_SK(sk);
	char buf1[DN_ASCBUF_LEN];
	char buf2[DN_ASCBUF_LEN];
	char local_object[DN_MAXOBJL+3];
	char remote_object[DN_MAXOBJL+3];

	dn_printable_object(&scp->addr, local_object);
	dn_printable_object(&scp->peer, remote_object);

	seq_printf(seq,
		   "%6s/%04X %04d:%04d %04d:%04d %01d %-16s "
		   "%6s/%04X %04d:%04d %04d:%04d %01d %-16s %4s %s\n",
		   dn_addr2asc(dn_ntohs(dn_saddr2dn(&scp->addr)), buf1),
		   scp->addrloc,
		   scp->numdat,
		   scp->numoth,
		   scp->ackxmt_dat,
		   scp->ackxmt_oth,
		   scp->flowloc_sw,
		   local_object,
		   dn_addr2asc(dn_ntohs(dn_saddr2dn(&scp->peer)), buf2),
		   scp->addrrem,
		   scp->numdat_rcv,
		   scp->numoth_rcv,
		   scp->ackrcv_dat,
		   scp->ackrcv_oth,
		   scp->flowrem_sw,
		   remote_object,
		   dn_state2asc(scp->state),
		   ((scp->accept_mode == ACC_IMMED) ? "IMMED" : "DEFER"));
}

static int dn_socket_seq_show(struct seq_file *seq, void *v)
{
	if (v == SEQ_START_TOKEN) {
		seq_puts(seq, "Local                                              Remote\n");
	} else {
		dn_socket_format_entry(seq, v);
	}
	return 0;
}

static const struct seq_operations dn_socket_seq_ops = {
	.start	= dn_socket_seq_start,
	.next	= dn_socket_seq_next,
	.stop	= dn_socket_seq_stop,
	.show	= dn_socket_seq_show,
};

static int dn_socket_seq_open(struct inode *inode, struct file *file)
{
	struct seq_file *seq;
	int rc = -ENOMEM;
	struct dn_iter_state *s = kmalloc(sizeof(*s), GFP_KERNEL);

	if (!s)
		goto out;

	rc = seq_open(file, &dn_socket_seq_ops);
	if (rc)
		goto out_kfree;

	seq		= file->private_data;
	seq->private	= s;
	memset(s, 0, sizeof(*s));
out:
	return rc;
out_kfree:
	kfree(s);
	goto out;
}

static const struct file_operations dn_socket_seq_fops = {
	.owner		= THIS_MODULE,
	.open		= dn_socket_seq_open,
	.read		= seq_read,
	.llseek		= seq_lseek,
	.release	= seq_release_private,
};
#endif

static struct net_proto_family	dn_family_ops = {
	.family =	AF_DECnet,
	.create =	dn_create,
	.owner	=	THIS_MODULE,
};

static const struct proto_ops dn_proto_ops = {
	.family =	AF_DECnet,
	.owner =	THIS_MODULE,
	.release =	dn_release,
	.bind =		dn_bind,
	.connect =	dn_connect,
	.socketpair =	sock_no_socketpair,
	.accept =	dn_accept,
	.getname =	dn_getname,
	.poll =		dn_poll,
	.ioctl =	dn_ioctl,
	.listen =	dn_listen,
	.shutdown =	dn_shutdown,
	.setsockopt =	dn_setsockopt,
	.getsockopt =	dn_getsockopt,
	.sendmsg =	dn_sendmsg,
	.recvmsg =	dn_recvmsg,
	.mmap =		sock_no_mmap,
	.sendpage =	sock_no_sendpage,
};

void dn_register_sysctl(void);
void dn_unregister_sysctl(void);

MODULE_DESCRIPTION("The Linux DECnet Network Protocol");
MODULE_AUTHOR("Linux DECnet Project Team");
MODULE_LICENSE("GPL");
MODULE_ALIAS_NETPROTO(PF_DECnet);

static char banner[] __initdata = KERN_INFO "NET4: DECnet for Linux: V.2.5.68s (C) 1995-2003 Linux DECnet Project Team\n";

static int __init decnet_init(void)
{
	int rc;

	printk(banner);

	rc = proto_register(&dn_proto, 1);
	if (rc != 0)
		goto out;

	dn_neigh_init();
	dn_dev_init();
	dn_route_init();
	dn_fib_init();

	sock_register(&dn_family_ops);
	dev_add_pack(&dn_dix_packet_type);
	register_netdevice_notifier(&dn_dev_notifier);

	proc_net_fops_create(&init_net, "decnet", S_IRUGO, &dn_socket_seq_fops);
	dn_register_sysctl();
out:
	return rc;

}
module_init(decnet_init);

/*
 * Prevent DECnet module unloading until its fixed properly.
 * Requires an audit of the code to check for memory leaks and
 * initialisation problems etc.
 */
#if 0
static void __exit decnet_exit(void)
{
	sock_unregister(AF_DECnet);
	rtnl_unregister_all(PF_DECnet);
	dev_remove_pack(&dn_dix_packet_type);

	dn_unregister_sysctl();

	unregister_netdevice_notifier(&dn_dev_notifier);

	dn_route_cleanup();
	dn_dev_cleanup();
	dn_neigh_cleanup();
	dn_fib_cleanup();

	proc_net_remove(&init_net, "decnet");

	proto_unregister(&dn_proto);
}
module_exit(decnet_exit);
#endif