- 根目录:
- net
- sched
- sch_atm.c
/* net/sched/sch_atm.c - ATM VC selection "queueing discipline" */
/* Written 1998-2000 by Werner Almesberger, EPFL ICA */
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/init.h>
#include <linux/interrupt.h>
#include <linux/string.h>
#include <linux/errno.h>
#include <linux/skbuff.h>
#include <linux/atmdev.h>
#include <linux/atmclip.h>
#include <linux/rtnetlink.h>
#include <linux/file.h> /* for fput */
#include <net/netlink.h>
#include <net/pkt_sched.h>
/*
* The ATM queuing discipline provides a framework for invoking classifiers
* (aka "filters"), which in turn select classes of this queuing discipline.
* Each class maps the flow(s) it is handling to a given VC. Multiple classes
* may share the same VC.
*
* When creating a class, VCs are specified by passing the number of the open
* socket descriptor by which the calling process references the VC. The kernel
* keeps the VC open at least until all classes using it are removed.
*
* In this file, most functions are named atm_tc_* to avoid confusion with all
* the atm_* in net/atm. This naming convention differs from what's used in the
* rest of net/sched.
*
* Known bugs:
* - sometimes messes up the IP stack
* - any manipulations besides the few operations described in the README, are
* untested and likely to crash the system
* - should lock the flow while there is data in the queue (?)
*/
#define VCC2FLOW(vcc) ((struct atm_flow_data *) ((vcc)->user_back))
struct atm_flow_data {
struct Qdisc *q; /* FIFO, TBF, etc. */
struct tcf_proto __rcu *filter_list;
struct atm_vcc *vcc; /* VCC; NULL if VCC is closed */
void (*old_pop)(struct atm_vcc *vcc,
struct sk_buff *skb); /* chaining */
struct atm_qdisc_data *parent; /* parent qdisc */
struct socket *sock; /* for closing */
u32 classid; /* x:y type ID */
int ref; /* reference count */
struct gnet_stats_basic_packed bstats;
struct gnet_stats_queue qstats;
struct list_head list;
struct atm_flow_data *excess; /* flow for excess traffic;
NULL to set CLP instead */
int hdr_len;
unsigned char hdr[0]; /* header data; MUST BE LAST */
};
struct atm_qdisc_data {
struct atm_flow_data link; /* unclassified skbs go here */
struct list_head flows; /* NB: "link" is also on this
list */
struct tasklet_struct task; /* dequeue tasklet */
};
/* ------------------------- Class/flow operations ------------------------- */
static inline struct atm_flow_data *lookup_flow(struct Qdisc *sch, u32 classid)
{
struct atm_qdisc_data *p = qdisc_priv(sch);
struct atm_flow_data *flow;
list_for_each_entry(flow, &p->flows, list) {
if (flow->classid == classid)
return flow;
}
return NULL;
}
static int atm_tc_graft(struct Qdisc *sch, unsigned long arg,
struct Qdisc *new, struct Qdisc **old)
{
struct atm_qdisc_data *p = qdisc_priv(sch);
struct atm_flow_data *flow = (struct atm_flow_data *)arg;
pr_debug("atm_tc_graft(sch %p,[qdisc %p],flow %p,new %p,old %p)\n",
sch, p, flow, new, old);
if (list_empty(&flow->list))
return -EINVAL;
if (!new)
new = &noop_qdisc;
*old = flow->q;
flow->q = new;
if (*old)
qdisc_reset(*old);
return 0;
}
static struct Qdisc *atm_tc_leaf(struct Qdisc *sch, unsigned long cl)
{
struct atm_flow_data *flow = (struct atm_flow_data *)cl;
pr_debug("atm_tc_leaf(sch %p,flow %p)\n", sch, flow);
return flow ? flow->q : NULL;
}
static unsigned long atm_tc_get(struct Qdisc *sch, u32 classid)
{
struct atm_qdisc_data *p __maybe_unused = qdisc_priv(sch);
struct atm_flow_data *flow;
pr_debug("atm_tc_get(sch %p,[qdisc %p],classid %x)\n", sch, p, classid);
flow = lookup_flow(sch, classid);
if (flow)
flow->ref++;
pr_debug("atm_tc_get: flow %p\n", flow);
return (unsigned long)flow;
}
static unsigned long atm_tc_bind_filter(struct Qdisc *sch,
unsigned long parent, u32 classid)
{
return atm_tc_get(sch, classid);
}
/*
* atm_tc_put handles all destructions, including the ones that are explicitly
* requested (atm_tc_destroy, etc.). The assumption here is that we never drop
* anything that still seems to be in use.
*/
static void atm_tc_put(struct Qdisc *sch, unsigned long cl)
{
struct atm_qdisc_data *p = qdisc_priv(sch);
struct atm_flow_data *flow = (struct atm_flow_data *)cl;
pr_debug("atm_tc_put(sch %p,[qdisc %p],flow %p)\n", sch, p, flow);
if (--flow->ref)
return;
pr_debug("atm_tc_put: destroying\n");
list_del_init(&flow->list);
pr_debug("atm_tc_put: qdisc %p\n", flow->q);
qdisc_destroy(flow->q);
tcf_destroy_chain(&flow->filter_list);
if (flow->sock) {
pr_debug("atm_tc_put: f_count %ld\n",
file_count(flow->sock->file));
flow->vcc->pop = flow->old_pop;
sockfd_put(flow->sock);
}
if (flow->excess)
atm_tc_put(sch, (unsigned long)flow->excess);
if (flow != &p->link)
kfree(flow);
/*
* If flow == &p->link, the qdisc no longer works at this point and
* needs to be removed. (By the caller of atm_tc_put.)
*/
}
static void sch_atm_pop(struct atm_vcc *vcc, struct sk_buff *skb)
{
struct atm_qdisc_data *p = VCC2FLOW(vcc)->parent;
pr_debug("sch_atm_pop(vcc %p,skb %p,[qdisc %p])\n", vcc, skb, p);
VCC2FLOW(vcc)->old_pop(vcc, skb);
tasklet_schedule(&p->task);
}
static const u8 llc_oui_ip[] = {
0xaa, /* DSAP: non-ISO */
0xaa, /* SSAP: non-ISO */
0x03, /* Ctrl: Unnumbered Information Command PDU */
0x00, /* OUI: EtherType */
0x00, 0x00,
0x08, 0x00
}; /* Ethertype IP (0800) */
static const struct nla_policy atm_policy[TCA_ATM_MAX + 1] = {
[TCA_ATM_FD] = { .type = NLA_U32 },
[TCA_ATM_EXCESS] = { .type = NLA_U32 },
};
static int atm_tc_change(struct Qdisc *sch, u32 classid, u32 parent,
struct nlattr **tca, unsigned long *arg)
{
struct atm_qdisc_data *p = qdisc_priv(sch);
struct atm_flow_data *flow = (struct atm_flow_data *)*arg;
struct atm_flow_data *excess = NULL;
struct nlattr *opt = tca[TCA_OPTIONS];
struct nlattr *tb[TCA_ATM_MAX + 1];
struct socket *sock;
int fd, error, hdr_len;
void *hdr;
pr_debug("atm_tc_change(sch %p,[qdisc %p],classid %x,parent %x,"
"flow %p,opt %p)\n", sch, p, classid, parent, flow, opt);
/*
* The concept of parents doesn't apply for this qdisc.
*/
if (parent && parent != TC_H_ROOT && parent != sch->handle)
return -EINVAL;
/*
* ATM classes cannot be changed. In order to change properties of the
* ATM connection, that socket needs to be modified directly (via the
* native ATM API. In order to send a flow to a different VC, the old
* class needs to be removed and a new one added. (This may be changed
* later.)
*/
if (flow)
return -EBUSY;
if (opt == NULL)
return -EINVAL;
error = nla_parse_nested(tb, TCA_ATM_MAX, opt, atm_policy);
if (error < 0)
return error;
if (!tb[TCA_ATM_FD])
return -EINVAL;
fd = nla_get_u32(tb[TCA_ATM_FD]);
pr_debug("atm_tc_change: fd %d\n", fd);
if (tb[TCA_ATM_HDR]) {
hdr_len = nla_len(tb[TCA_ATM_HDR]);
hdr = nla_data(tb[TCA_ATM_HDR]);
} else {
hdr_len = RFC1483LLC_LEN;
hdr = NULL; /* default LLC/SNAP for IP */
}
if (!tb[TCA_ATM_EXCESS])
excess = NULL;
else {
excess = (struct atm_flow_data *)
atm_tc_get(sch, nla_get_u32(tb[TCA_ATM_EXCESS]));
if (!excess)
return -ENOENT;
}
pr_debug("atm_tc_change: type %d, payload %d, hdr_len %d\n",
opt->nla_type, nla_len(opt), hdr_len);
sock = sockfd_lookup(fd, &error);
if (!sock)
return error; /* f_count++ */
pr_debug("atm_tc_change: f_count %ld\n", file_count(sock->file));
if (sock->ops->family != PF_ATMSVC && sock->ops->family != PF_ATMPVC) {
error = -EPROTOTYPE;
goto err_out;
}
/* @@@ should check if the socket is really operational or we'll crash
on vcc->send */
if (classid) {
if (TC_H_MAJ(classid ^ sch->handle)) {
pr_debug("atm_tc_change: classid mismatch\n");
error = -EINVAL;
goto err_out;
}
} else {
int i;
unsigned long cl;
for (i = 1; i < 0x8000; i++) {
classid = TC_H_MAKE(sch->handle, 0x8000 | i);
cl = atm_tc_get(sch, classid);
if (!cl)
break;
atm_tc_put(sch, cl);
}
}
pr_debug("atm_tc_change: new id %x\n", classid);
flow = kzalloc(sizeof(struct atm_flow_data) + hdr_len, GFP_KERNEL);
pr_debug("atm_tc_change: flow %p\n", flow);
if (!flow) {
error = -ENOBUFS;
goto err_out;
}
RCU_INIT_POINTER(flow->filter_list, NULL);
flow->q = qdisc_create_dflt(sch->dev_queue, &pfifo_qdisc_ops, classid);
if (!flow->q)
flow->q = &noop_qdisc;
pr_debug("atm_tc_change: qdisc %p\n", flow->q);
flow->sock = sock;
flow->vcc = ATM_SD(sock); /* speedup */
flow->vcc->user_back = flow;
pr_debug("atm_tc_change: vcc %p\n", flow->vcc);
flow->old_pop = flow->vcc->pop;
flow->parent = p;
flow->vcc->pop = sch_atm_pop;
flow->classid = classid;
flow->ref = 1;
flow->excess = excess;
list_add(&flow->list, &p->link.list);
flow->hdr_len = hdr_len;
if (hdr)
memcpy(flow->hdr, hdr, hdr_len);
else
memcpy(flow->hdr, llc_oui_ip, sizeof(llc_oui_ip));
*arg = (unsigned long)flow;
return 0;
err_out:
if (excess)
atm_tc_put(sch, (unsigned long)excess);
sockfd_put(sock);
return error;
}
static int atm_tc_delete(struct Qdisc *sch, unsigned long arg)
{
struct atm_qdisc_data *p = qdisc_priv(sch);
struct atm_flow_data *flow = (struct atm_flow_data *)arg;
pr_debug("atm_tc_delete(sch %p,[qdisc %p],flow %p)\n", sch, p, flow);
if (list_empty(&flow->list))
return -EINVAL;
if (rcu_access_pointer(flow->filter_list) || flow == &p->link)
return -EBUSY;
/*
* Reference count must be 2: one for "keepalive" (set at class
* creation), and one for the reference held when calling delete.
*/
if (flow->ref < 2) {
pr_err("atm_tc_delete: flow->ref == %d\n", flow->ref);
return -EINVAL;
}
if (flow->ref > 2)
return -EBUSY; /* catch references via excess, etc. */
atm_tc_put(sch, arg);
return 0;
}
static void atm_tc_walk(struct Qdisc *sch, struct qdisc_walker *walker)
{
struct atm_qdisc_data *p = qdisc_priv(sch);
struct atm_flow_data *flow;
pr_debug("atm_tc_walk(sch %p,[qdisc %p],walker %p)\n", sch, p, walker);
if (walker->stop)
return;
list_for_each_entry(flow, &p->flows, list) {
if (walker->count >= walker->skip &&
walker->fn(sch, (unsigned long)flow, walker) < 0) {
walker->stop = 1;
break;
}
walker->count++;
}
}
static struct tcf_proto __rcu **atm_tc_find_tcf(struct Qdisc *sch,
unsigned long cl)
{
struct atm_qdisc_data *p = qdisc_priv(sch);
struct atm_flow_data *flow = (struct atm_flow_data *)cl;
pr_debug("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 = qdisc_priv(sch);
struct atm_flow_data *flow;
struct tcf_result res;
int result;
int ret = NET_XMIT_POLICED;
pr_debug("atm_tc_enqueue(skb %p,sch %p,[qdisc %p])\n", skb, sch, p);
result = TC_POLICE_OK; /* be nice to gcc */
flow = NULL;
if (TC_H_MAJ(skb->priority) != sch->handle ||
!(flow = (struct atm_flow_data *)atm_tc_get(sch, skb->priority))) {
struct tcf_proto *fl;
list_for_each_entry(flow, &p->flows, list) {
fl = rcu_dereference_bh(flow->filter_list);
if (fl) {
result = tc_classify(skb, fl, &res, true);
if (result < 0)
continue;
flow = (struct atm_flow_data *)res.class;
if (!flow)
flow = lookup_flow(sch, res.classid);
goto done;
}
}
flow = NULL;
done:
;
}
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 | __NET_XMIT_STOLEN;
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
}
ret = qdisc_enqueue(skb, flow->q);
if (ret != NET_XMIT_SUCCESS) {
drop: __maybe_unused
if (net_xmit_drop_count(ret)) {
qdisc_qstats_drop(sch);
if (flow)
flow->qstats.drops++;
}
return ret;
}
/*
* 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 NET_XMIT_SUCCESS;
}
tasklet_schedule(&p->task);
return NET_XMIT_SUCCESS | __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 = qdisc_priv(sch);
struct atm_flow_data *flow;
struct sk_buff *skb;
pr_debug("sch_atm_dequeue(sch %p,[qdisc %p])\n", sch, p);
list_for_each_entry(flow, &p->flows, list) {
if (flow == &p->link)
continue;
/*
* If traffic is properly shaped, this won't generate nasty
* little bursts. Otherwise, it may ... (but that's okay)
*/
while ((skb = flow->q->ops->peek(flow->q))) {
if (!atm_may_send(flow->vcc, skb->truesize))
break;
skb = qdisc_dequeue_peeked(flow->q);
if (unlikely(!skb))
break;
qdisc_bstats_update(sch, skb);
bstats_update(&flow->bstats, skb);
pr_debug("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;
}
pr_debug("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 = qdisc_priv(sch);
struct sk_buff *skb;
pr_debug("atm_tc_dequeue(sch %p,[qdisc %p])\n", sch, p);
tasklet_schedule(&p->task);
skb = qdisc_dequeue_peeked(p->link.q);
if (skb)
sch->q.qlen--;
return skb;
}
static struct sk_buff *atm_tc_peek(struct Qdisc *sch)
{
struct atm_qdisc_data *p = qdisc_priv(sch);
pr_debug("atm_tc_peek(sch %p,[qdisc %p])\n", sch, p);
return p->link.q->ops->peek(p->link.q);
}
static unsigned int atm_tc_drop(struct Qdisc *sch)
{
struct atm_qdisc_data *p = qdisc_priv(sch);
struct atm_flow_data *flow;
unsigned int len;
pr_debug("atm_tc_drop(sch %p,[qdisc %p])\n", sch, p);
list_for_each_entry(flow, &p->flows, list) {
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 nlattr *opt)
{
struct atm_qdisc_data *p = qdisc_priv(sch);
pr_debug("atm_tc_init(sch %p,[qdisc %p],opt %p)\n", sch, p, opt);
INIT_LIST_HEAD(&p->flows);
INIT_LIST_HEAD(&p->link.list);
list_add(&p->link.list, &p->flows);
p->link.q = qdisc_create_dflt(sch->dev_queue,
&pfifo_qdisc_ops, sch->handle);
if (!p->link.q)
p->link.q = &noop_qdisc;
pr_debug("atm_tc_init: link (%p) qdisc %p\n", &p->link, p->link.q);
RCU_INIT_POINTER(p->link.filter_list, NULL);
p->link.vcc = NULL;
p->link.sock = NULL;
p->link.classid = sch->handle;
p->link.ref = 1;
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 = qdisc_priv(sch);
struct atm_flow_data *flow;
pr_debug("atm_tc_reset(sch %p,[qdisc %p])\n", sch, p);
list_for_each_entry(flow, &p->flows, list)
qdisc_reset(flow->q);
sch->q.qlen = 0;
}
static void atm_tc_destroy(struct Qdisc *sch)
{
struct atm_qdisc_data *p = qdisc_priv(sch);
struct atm_flow_data *flow, *tmp;
pr_debug("atm_tc_destroy(sch %p,[qdisc %p])\n", sch, p);
list_for_each_entry(flow, &p->flows, list)
tcf_destroy_chain(&flow->filter_list);
list_for_each_entry_safe(flow, tmp, &p->flows, list) {
if (flow->ref > 1)
pr_err("atm_destroy: %p->ref = %d\n", flow, flow->ref);
atm_tc_put(sch, (unsigned long)flow);
}
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 = qdisc_priv(sch);
struct atm_flow_data *flow = (struct atm_flow_data *)cl;
struct nlattr *nest;
pr_debug("atm_tc_dump_class(sch %p,[qdisc %p],flow %p,skb %p,tcm %p)\n",
sch, p, flow, skb, tcm);
if (list_empty(&flow->list))
return -EINVAL;
tcm->tcm_handle = flow->classid;
tcm->tcm_info = flow->q->handle;
nest = nla_nest_start(skb, TCA_OPTIONS);
if (nest == NULL)
goto nla_put_failure;
if (nla_put(skb, TCA_ATM_HDR, flow->hdr_len, flow->hdr))
goto nla_put_failure;
if (flow->vcc) {
struct sockaddr_atmpvc pvc;
int state;
memset(&pvc, 0, sizeof(pvc));
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;
if (nla_put(skb, TCA_ATM_ADDR, sizeof(pvc), &pvc))
goto nla_put_failure;
state = ATM_VF2VS(flow->vcc->flags);
if (nla_put_u32(skb, TCA_ATM_STATE, state))
goto nla_put_failure;
}
if (flow->excess) {
if (nla_put_u32(skb, TCA_ATM_EXCESS, flow->classid))
goto nla_put_failure;
} else {
if (nla_put_u32(skb, TCA_ATM_EXCESS, 0))
goto nla_put_failure;
}
return nla_nest_end(skb, nest);
nla_put_failure:
nla_nest_cancel(skb, nest);
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;
if (gnet_stats_copy_basic(d, NULL, &flow->bstats) < 0 ||
gnet_stats_copy_queue(d, NULL, &flow->qstats, flow->q->q.qlen) < 0)
return -1;
return 0;
}
static int atm_tc_dump(struct Qdisc *sch, struct sk_buff *skb)
{
return 0;
}
static const 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 __read_mostly = {
.cl_ops = &atm_class_ops,
.id = "atm",
.priv_size = sizeof(struct atm_qdisc_data),
.enqueue = atm_tc_enqueue,
.dequeue = atm_tc_dequeue,
.peek = atm_tc_peek,
.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");