dn_neigh.c

linux 内核源代码

	skb_reset_network_header(skb);

	return NF_HOOK(PF_DECnet, NF_DN_POST_ROUTING, skb, NULL, neigh->dev, dn_neigh_output_packet);
}

/*
 * Phase 3 output is the same is short output, execpt that
 * it clears the area bits before transmission.
 */
static int dn_phase3_output(struct sk_buff *skb)
{
	struct dst_entry *dst = skb->dst;
	struct neighbour *neigh = dst->neighbour;
	struct net_device *dev = neigh->dev;
	int headroom = dev->hard_header_len + sizeof(struct dn_short_packet) + 2;
	struct dn_short_packet *sp;
	unsigned char *data;
	struct dn_skb_cb *cb = DN_SKB_CB(skb);

	if (skb_headroom(skb) < headroom) {
		struct sk_buff *skb2 = skb_realloc_headroom(skb, headroom);
		if (skb2 == NULL) {
			if (net_ratelimit())
				printk(KERN_CRIT "dn_phase3_output: no memory\n");
			kfree_skb(skb);
			return -ENOBUFS;
		}
		kfree_skb(skb);
		skb = skb2;
		if (net_ratelimit())
			printk(KERN_INFO "dn_phase3_output: Increasing headroom\n");
	}

	data = skb_push(skb, sizeof(struct dn_short_packet) + 2);
	*((__le16 *)data) = dn_htons(skb->len - 2);
	sp = (struct dn_short_packet *)(data + 2);

	sp->msgflg   = DN_RT_PKT_SHORT|(cb->rt_flags&(DN_RT_F_RQR|DN_RT_F_RTS));
	sp->dstnode  = cb->dst & dn_htons(0x03ff);
	sp->srcnode  = cb->src & dn_htons(0x03ff);
	sp->forward  = cb->hops & 0x3f;

	skb_reset_network_header(skb);

	return NF_HOOK(PF_DECnet, NF_DN_POST_ROUTING, skb, NULL, neigh->dev, dn_neigh_output_packet);
}

/*
 * Unfortunately, the neighbour code uses the device in its hash
 * function, so we don't get any advantage from it. This function
 * basically does a neigh_lookup(), but without comparing the device
 * field. This is required for the On-Ethernet cache
 */

/*
 * Pointopoint link receives a hello message
 */
void dn_neigh_pointopoint_hello(struct sk_buff *skb)
{
	kfree_skb(skb);
}

/*
 * Ethernet router hello message received
 */
int dn_neigh_router_hello(struct sk_buff *skb)
{
	struct rtnode_hello_message *msg = (struct rtnode_hello_message *)skb->data;

	struct neighbour *neigh;
	struct dn_neigh *dn;
	struct dn_dev *dn_db;
	__le16 src;

	src = dn_eth2dn(msg->id);

	neigh = __neigh_lookup(&dn_neigh_table, &src, skb->dev, 1);

	dn = (struct dn_neigh *)neigh;

	if (neigh) {
		write_lock(&neigh->lock);

		neigh->used = jiffies;
		dn_db = (struct dn_dev *)neigh->dev->dn_ptr;

		if (!(neigh->nud_state & NUD_PERMANENT)) {
			neigh->updated = jiffies;

			if (neigh->dev->type == ARPHRD_ETHER)
				memcpy(neigh->ha, &eth_hdr(skb)->h_source, ETH_ALEN);

			dn->blksize  = dn_ntohs(msg->blksize);
			dn->priority = msg->priority;

			dn->flags &= ~DN_NDFLAG_P3;

			switch(msg->iinfo & DN_RT_INFO_TYPE) {
				case DN_RT_INFO_L1RT:
					dn->flags &=~DN_NDFLAG_R2;
					dn->flags |= DN_NDFLAG_R1;
					break;
				case DN_RT_INFO_L2RT:
					dn->flags |= DN_NDFLAG_R2;
			}
		}

		/* Only use routers in our area */
		if ((dn_ntohs(src)>>10) == (dn_ntohs((decnet_address))>>10)) {
			if (!dn_db->router) {
				dn_db->router = neigh_clone(neigh);
			} else {
				if (msg->priority > ((struct dn_neigh *)dn_db->router)->priority)
					neigh_release(xchg(&dn_db->router, neigh_clone(neigh)));
			}
		}
		write_unlock(&neigh->lock);
		neigh_release(neigh);
	}

	kfree_skb(skb);
	return 0;
}

/*
 * Endnode hello message received
 */
int dn_neigh_endnode_hello(struct sk_buff *skb)
{
	struct endnode_hello_message *msg = (struct endnode_hello_message *)skb->data;
	struct neighbour *neigh;
	struct dn_neigh *dn;
	__le16 src;

	src = dn_eth2dn(msg->id);

	neigh = __neigh_lookup(&dn_neigh_table, &src, skb->dev, 1);

	dn = (struct dn_neigh *)neigh;

	if (neigh) {
		write_lock(&neigh->lock);

		neigh->used = jiffies;

		if (!(neigh->nud_state & NUD_PERMANENT)) {
			neigh->updated = jiffies;

			if (neigh->dev->type == ARPHRD_ETHER)
				memcpy(neigh->ha, &eth_hdr(skb)->h_source, ETH_ALEN);
			dn->flags   &= ~(DN_NDFLAG_R1 | DN_NDFLAG_R2);
			dn->blksize  = dn_ntohs(msg->blksize);
			dn->priority = 0;
		}

		write_unlock(&neigh->lock);
		neigh_release(neigh);
	}

	kfree_skb(skb);
	return 0;
}

static char *dn_find_slot(char *base, int max, int priority)
{
	int i;
	unsigned char *min = NULL;

	base += 6; /* skip first id */

	for(i = 0; i < max; i++) {
		if (!min || (*base < *min))
			min = base;
		base += 7; /* find next priority */
	}

	if (!min)
		return NULL;

	return (*min < priority) ? (min - 6) : NULL;
}

struct elist_cb_state {
	struct net_device *dev;
	unsigned char *ptr;
	unsigned char *rs;
	int t, n;
};

static void neigh_elist_cb(struct neighbour *neigh, void *_info)
{
	struct elist_cb_state *s = _info;
	struct dn_neigh *dn;

	if (neigh->dev != s->dev)
		return;

	dn = (struct dn_neigh *) neigh;
	if (!(dn->flags & (DN_NDFLAG_R1|DN_NDFLAG_R2)))
		return;

	if (s->t == s->n)
		s->rs = dn_find_slot(s->ptr, s->n, dn->priority);
	else
		s->t++;
	if (s->rs == NULL)
		return;

	dn_dn2eth(s->rs, dn->addr);
	s->rs += 6;
	*(s->rs) = neigh->nud_state & NUD_CONNECTED ? 0x80 : 0x0;
	*(s->rs) |= dn->priority;
	s->rs++;
}

int dn_neigh_elist(struct net_device *dev, unsigned char *ptr, int n)
{
	struct elist_cb_state state;

	state.dev = dev;
	state.t = 0;
	state.n = n;
	state.ptr = ptr;
	state.rs = ptr;

	neigh_for_each(&dn_neigh_table, neigh_elist_cb, &state);

	return state.t;
}


#ifdef CONFIG_PROC_FS

static inline void dn_neigh_format_entry(struct seq_file *seq,
					 struct neighbour *n)
{
	struct dn_neigh *dn = (struct dn_neigh *) n;
	char buf[DN_ASCBUF_LEN];

	read_lock(&n->lock);
	seq_printf(seq, "%-7s %s%s%s   %02x    %02d  %07ld %-8s\n",
		   dn_addr2asc(dn_ntohs(dn->addr), buf),
		   (dn->flags&DN_NDFLAG_R1) ? "1" : "-",
		   (dn->flags&DN_NDFLAG_R2) ? "2" : "-",
		   (dn->flags&DN_NDFLAG_P3) ? "3" : "-",
		   dn->n.nud_state,
		   atomic_read(&dn->n.refcnt),
		   dn->blksize,
		   (dn->n.dev) ? dn->n.dev->name : "?");
	read_unlock(&n->lock);
}

static int dn_neigh_seq_show(struct seq_file *seq, void *v)
{
	if (v == SEQ_START_TOKEN) {
		seq_puts(seq, "Addr    Flags State Use Blksize Dev\n");
	} else {
		dn_neigh_format_entry(seq, v);
	}

	return 0;
}

static void *dn_neigh_seq_start(struct seq_file *seq, loff_t *pos)
{
	return neigh_seq_start(seq, pos, &dn_neigh_table,
			       NEIGH_SEQ_NEIGH_ONLY);
}

static const struct seq_operations dn_neigh_seq_ops = {
	.start = dn_neigh_seq_start,
	.next  = neigh_seq_next,
	.stop  = neigh_seq_stop,
	.show  = dn_neigh_seq_show,
};

static int dn_neigh_seq_open(struct inode *inode, struct file *file)
{
	return seq_open_private(file, &dn_neigh_seq_ops,
			sizeof(struct neigh_seq_state));
}

static const struct file_operations dn_neigh_seq_fops = {
	.owner		= THIS_MODULE,
	.open		= dn_neigh_seq_open,
	.read		= seq_read,
	.llseek		= seq_lseek,
	.release	= seq_release_private,
};

#endif

void __init dn_neigh_init(void)
{
	neigh_table_init(&dn_neigh_table);
	proc_net_fops_create(&init_net, "decnet_neigh", S_IRUGO, &dn_neigh_seq_fops);
}

void __exit dn_neigh_cleanup(void)
{
	proc_net_remove(&init_net, "decnet_neigh");
	neigh_table_clear(&dn_neigh_table);
}