linux-imx

/* 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>

#include <net/pkt_cls.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_class_common common;

    struct Qdisc        *q; /* FIFO, TBF, etc. */

    struct tcf_proto __rcu  *filter_list;

    struct tcf_block    *block;

    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 */

    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->common.classid == classid)

            return flow;

    }

    return NULL;

}

​

static int atm_tc_graft(struct Qdisc *sch, unsigned long arg,

            struct Qdisc *new, struct Qdisc **old,

            struct netlink_ext_ack *extack)

{

    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);