sch_atm.c

linux 内核源代码

	struct atm_flow_data *flow;

	DPRINTK("atm_tc_walk(sch %p,[qdisc %p],walker %p)\n", sch, p, walker);
	if (walker->stop)
		return;
	for (flow = p->flows; flow; flow = flow->next) {
		if (walker->count >= walker->skip)
			if (walker->fn(sch, (unsigned long)flow, walker) < 0) {
				walker->stop = 1;
				break;
			}
		walker->count++;
	}
}

static struct tcf_proto **atm_tc_find_tcf(struct Qdisc *sch, unsigned long cl)
{
	struct atm_qdisc_data *p = PRIV(sch);
	struct atm_flow_data *flow = (struct atm_flow_data *)cl;

	DPRINTK("atm_tc_find_tcf(sch %p,[qdisc %p],flow %p)\n", sch, p, flow);
	return flow ? &flow->filter_list : &p->link.filter_list;
}

/* --------------------------- Qdisc operations ---------------------------- */

static int atm_tc_enqueue(struct sk_buff *skb, struct Qdisc *sch)
{
	struct atm_qdisc_data *p = PRIV(sch);
	struct atm_flow_data *flow = NULL;	/* @@@ */
	struct tcf_result res;
	int result;
	int ret = NET_XMIT_POLICED;

	D2PRINTK("atm_tc_enqueue(skb %p,sch %p,[qdisc %p])\n", skb, sch, p);
	result = TC_POLICE_OK;	/* be nice to gcc */
	if (TC_H_MAJ(skb->priority) != sch->handle ||
	    !(flow = (struct atm_flow_data *)atm_tc_get(sch, skb->priority)))
		for (flow = p->flows; flow; flow = flow->next)
			if (flow->filter_list) {
				result = tc_classify_compat(skb,
							    flow->filter_list,
							    &res);
				if (result < 0)
					continue;
				flow = (struct atm_flow_data *)res.class;
				if (!flow)
					flow = lookup_flow(sch, res.classid);
				break;
			}
	if (!flow)
		flow = &p->link;
	else {
		if (flow->vcc)
			ATM_SKB(skb)->atm_options = flow->vcc->atm_options;
		/*@@@ looks good ... but it's not supposed to work :-) */
#ifdef CONFIG_NET_CLS_ACT
		switch (result) {
		case TC_ACT_QUEUED:
		case TC_ACT_STOLEN:
			kfree_skb(skb);
			return NET_XMIT_SUCCESS;
		case TC_ACT_SHOT:
			kfree_skb(skb);
			goto drop;
		case TC_POLICE_RECLASSIFY:
			if (flow->excess)
				flow = flow->excess;
			else
				ATM_SKB(skb)->atm_options |= ATM_ATMOPT_CLP;
			break;
		}
#endif
	}

	if ((ret = flow->q->enqueue(skb, flow->q)) != 0) {
drop: __maybe_unused
		sch->qstats.drops++;
		if (flow)
			flow->qstats.drops++;
		return ret;
	}
	sch->bstats.bytes += skb->len;
	sch->bstats.packets++;
	flow->bstats.bytes += skb->len;
	flow->bstats.packets++;
	/*
	 * Okay, this may seem weird. We pretend we've dropped the packet if
	 * it goes via ATM. The reason for this is that the outer qdisc
	 * expects to be able to q->dequeue the packet later on if we return
	 * success at this place. Also, sch->q.qdisc needs to reflect whether
	 * there is a packet egligible for dequeuing or not. Note that the
	 * statistics of the outer qdisc are necessarily wrong because of all
	 * this. There's currently no correct solution for this.
	 */
	if (flow == &p->link) {
		sch->q.qlen++;
		return 0;
	}
	tasklet_schedule(&p->task);
	return NET_XMIT_BYPASS;
}

/*
 * Dequeue packets and send them over ATM. Note that we quite deliberately
 * avoid checking net_device's flow control here, simply because sch_atm
 * uses its own channels, which have nothing to do with any CLIP/LANE/or
 * non-ATM interfaces.
 */

static void sch_atm_dequeue(unsigned long data)
{
	struct Qdisc *sch = (struct Qdisc *)data;
	struct atm_qdisc_data *p = PRIV(sch);
	struct atm_flow_data *flow;
	struct sk_buff *skb;

	D2PRINTK("sch_atm_dequeue(sch %p,[qdisc %p])\n", sch, p);
	for (flow = p->link.next; flow; flow = flow->next)
		/*
		 * If traffic is properly shaped, this won't generate nasty
		 * little bursts. Otherwise, it may ... (but that's okay)
		 */
		while ((skb = flow->q->dequeue(flow->q))) {
			if (!atm_may_send(flow->vcc, skb->truesize)) {
				(void)flow->q->ops->requeue(skb, flow->q);
				break;
			}
			D2PRINTK("atm_tc_dequeue: sending on class %p\n", flow);
			/* remove any LL header somebody else has attached */
			skb_pull(skb, skb_network_offset(skb));
			if (skb_headroom(skb) < flow->hdr_len) {
				struct sk_buff *new;

				new = skb_realloc_headroom(skb, flow->hdr_len);
				dev_kfree_skb(skb);
				if (!new)
					continue;
				skb = new;
			}
			D2PRINTK("sch_atm_dequeue: ip %p, data %p\n",
				 skb_network_header(skb), skb->data);
			ATM_SKB(skb)->vcc = flow->vcc;
			memcpy(skb_push(skb, flow->hdr_len), flow->hdr,
			       flow->hdr_len);
			atomic_add(skb->truesize,
				   &sk_atm(flow->vcc)->sk_wmem_alloc);
			/* atm.atm_options are already set by atm_tc_enqueue */
			flow->vcc->send(flow->vcc, skb);
		}
}

static struct sk_buff *atm_tc_dequeue(struct Qdisc *sch)
{
	struct atm_qdisc_data *p = PRIV(sch);
	struct sk_buff *skb;

	D2PRINTK("atm_tc_dequeue(sch %p,[qdisc %p])\n", sch, p);
	tasklet_schedule(&p->task);
	skb = p->link.q->dequeue(p->link.q);
	if (skb)
		sch->q.qlen--;
	return skb;
}

static int atm_tc_requeue(struct sk_buff *skb, struct Qdisc *sch)
{
	struct atm_qdisc_data *p = PRIV(sch);
	int ret;

	D2PRINTK("atm_tc_requeue(skb %p,sch %p,[qdisc %p])\n", skb, sch, p);
	ret = p->link.q->ops->requeue(skb, p->link.q);
	if (!ret) {
		sch->q.qlen++;
		sch->qstats.requeues++;
	} else {
		sch->qstats.drops++;
		p->link.qstats.drops++;
	}
	return ret;
}

static unsigned int atm_tc_drop(struct Qdisc *sch)
{
	struct atm_qdisc_data *p = PRIV(sch);
	struct atm_flow_data *flow;
	unsigned int len;

	DPRINTK("atm_tc_drop(sch %p,[qdisc %p])\n", sch, p);
	for (flow = p->flows; flow; flow = flow->next)
		if (flow->q->ops->drop && (len = flow->q->ops->drop(flow->q)))
			return len;
	return 0;
}

static int atm_tc_init(struct Qdisc *sch, struct rtattr *opt)
{
	struct atm_qdisc_data *p = PRIV(sch);

	DPRINTK("atm_tc_init(sch %p,[qdisc %p],opt %p)\n", sch, p, opt);
	p->flows = &p->link;
	if (!(p->link.q = qdisc_create_dflt(sch->dev, &pfifo_qdisc_ops,
					    sch->handle)))
		p->link.q = &noop_qdisc;
	DPRINTK("atm_tc_init: link (%p) qdisc %p\n", &p->link, p->link.q);
	p->link.filter_list = NULL;
	p->link.vcc = NULL;
	p->link.sock = NULL;
	p->link.classid = sch->handle;
	p->link.ref = 1;
	p->link.next = NULL;
	tasklet_init(&p->task, sch_atm_dequeue, (unsigned long)sch);
	return 0;
}

static void atm_tc_reset(struct Qdisc *sch)
{
	struct atm_qdisc_data *p = PRIV(sch);
	struct atm_flow_data *flow;

	DPRINTK("atm_tc_reset(sch %p,[qdisc %p])\n", sch, p);
	for (flow = p->flows; flow; flow = flow->next)
		qdisc_reset(flow->q);
	sch->q.qlen = 0;
}

static void atm_tc_destroy(struct Qdisc *sch)
{
	struct atm_qdisc_data *p = PRIV(sch);
	struct atm_flow_data *flow;

	DPRINTK("atm_tc_destroy(sch %p,[qdisc %p])\n", sch, p);
	/* races ? */
	while ((flow = p->flows)) {
		tcf_destroy_chain(flow->filter_list);
		flow->filter_list = NULL;
		if (flow->ref > 1)
			printk(KERN_ERR "atm_destroy: %p->ref = %d\n", flow,
			       flow->ref);
		atm_tc_put(sch, (unsigned long)flow);
		if (p->flows == flow) {
			printk(KERN_ERR "atm_destroy: putting flow %p didn't "
			       "kill it\n", flow);
			p->flows = flow->next;	/* brute force */
			break;
		}
	}
	tasklet_kill(&p->task);
}

static int atm_tc_dump_class(struct Qdisc *sch, unsigned long cl,
			     struct sk_buff *skb, struct tcmsg *tcm)
{
	struct atm_qdisc_data *p = PRIV(sch);
	struct atm_flow_data *flow = (struct atm_flow_data *)cl;
	unsigned char *b = skb_tail_pointer(skb);
	struct rtattr *rta;

	DPRINTK("atm_tc_dump_class(sch %p,[qdisc %p],flow %p,skb %p,tcm %p)\n",
		sch, p, flow, skb, tcm);
	if (!find_flow(p, flow))
		return -EINVAL;
	tcm->tcm_handle = flow->classid;
	tcm->tcm_info = flow->q->handle;
	rta = (struct rtattr *)b;
	RTA_PUT(skb, TCA_OPTIONS, 0, NULL);
	RTA_PUT(skb, TCA_ATM_HDR, flow->hdr_len, flow->hdr);
	if (flow->vcc) {
		struct sockaddr_atmpvc pvc;
		int state;

		pvc.sap_family = AF_ATMPVC;
		pvc.sap_addr.itf = flow->vcc->dev ? flow->vcc->dev->number : -1;
		pvc.sap_addr.vpi = flow->vcc->vpi;
		pvc.sap_addr.vci = flow->vcc->vci;
		RTA_PUT(skb, TCA_ATM_ADDR, sizeof(pvc), &pvc);
		state = ATM_VF2VS(flow->vcc->flags);
		RTA_PUT(skb, TCA_ATM_STATE, sizeof(state), &state);
	}
	if (flow->excess)
		RTA_PUT(skb, TCA_ATM_EXCESS, sizeof(u32), &flow->classid);
	else {
		static u32 zero;

		RTA_PUT(skb, TCA_ATM_EXCESS, sizeof(zero), &zero);
	}
	rta->rta_len = skb_tail_pointer(skb) - b;
	return skb->len;

rtattr_failure:
	nlmsg_trim(skb, b);
	return -1;
}
static int
atm_tc_dump_class_stats(struct Qdisc *sch, unsigned long arg,
			struct gnet_dump *d)
{
	struct atm_flow_data *flow = (struct atm_flow_data *)arg;

	flow->qstats.qlen = flow->q->q.qlen;

	if (gnet_stats_copy_basic(d, &flow->bstats) < 0 ||
	    gnet_stats_copy_queue(d, &flow->qstats) < 0)
		return -1;

	return 0;
}

static int atm_tc_dump(struct Qdisc *sch, struct sk_buff *skb)
{
	return 0;
}

static struct Qdisc_class_ops atm_class_ops = {
	.graft		= atm_tc_graft,
	.leaf		= atm_tc_leaf,
	.get		= atm_tc_get,
	.put		= atm_tc_put,
	.change		= atm_tc_change,
	.delete		= atm_tc_delete,
	.walk		= atm_tc_walk,
	.tcf_chain	= atm_tc_find_tcf,
	.bind_tcf	= atm_tc_bind_filter,
	.unbind_tcf	= atm_tc_put,
	.dump		= atm_tc_dump_class,
	.dump_stats	= atm_tc_dump_class_stats,
};

static struct Qdisc_ops atm_qdisc_ops = {
	.cl_ops		= &atm_class_ops,
	.id		= "atm",
	.priv_size	= sizeof(struct atm_qdisc_data),
	.enqueue	= atm_tc_enqueue,
	.dequeue	= atm_tc_dequeue,
	.requeue	= atm_tc_requeue,
	.drop		= atm_tc_drop,
	.init		= atm_tc_init,
	.reset		= atm_tc_reset,
	.destroy	= atm_tc_destroy,
	.dump		= atm_tc_dump,
	.owner		= THIS_MODULE,
};

static int __init atm_init(void)
{
	return register_qdisc(&atm_qdisc_ops);
}

static void __exit atm_exit(void)
{
	unregister_qdisc(&atm_qdisc_ops);
}

module_init(atm_init)
module_exit(atm_exit)
MODULE_LICENSE("GPL");