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/* net/sched/sch_atm.c - ATM VC selection "queueing discipline" */

/* Written 1998-2000 by Werner Almesberger, EPFL ICA */

#include <linux/module.h>

#include <linux/init.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>

extern struct socket *sockfd_lookup(int fd, int *err);  /* @@@ fix this */

#if 0 /* control */

#define DPRINTK(format,args...) printk(KERN_DEBUG format,##args)

#else

#define DPRINTK(format,args...)

#endif

#if 0 /* data */

#define D2PRINTK(format,args...) printk(KERN_DEBUG format,##args)

#else

#define D2PRINTK(format,args...)

#endif

/*

 * 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 PRIV(sch) qdisc_priv(sch)

#define VCC2FLOW(vcc) ((struct atm_flow_data *) ((vcc)->user_back))

struct atm_flow_data {

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

        struct tcf_proto        *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 bstats;

        struct gnet_stats_queue qstats;

        struct atm_flow_data    *next;

        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 atm_flow_data    *flows;         /* NB: "link" is also on this

                                                   list */

        struct tasklet_struct   task;           /* requeue tasklet */

};

/* ------------------------- Class/flow operations ------------------------- */

static int find_flow(struct atm_qdisc_data *qdisc, struct atm_flow_data *flow)

{

        struct atm_flow_data *walk;

        DPRINTK("find_flow(qdisc %p,flow %p)\n", qdisc, flow);

        for (walk = qdisc->flows; walk; walk = walk->next)

                if (walk == flow)

                        return 1;

        DPRINTK("find_flow: not found\n");

        return 0;

}

static inline struct atm_flow_data *lookup_flow(struct Qdisc *sch, u32 classid)

{

        struct atm_qdisc_data *p = PRIV(sch);

        struct atm_flow_data *flow;

        for (flow = p->flows; flow; flow = flow->next)

                if (flow->classid == classid)

                        break;

        return flow;

}

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

                        struct Qdisc *new, struct Qdisc **old)

{

        struct atm_qdisc_data *p = PRIV(sch);

        struct atm_flow_data *flow = (struct atm_flow_data *)arg;

        DPRINTK("atm_tc_graft(sch %p,[qdisc %p],flow %p,new %p,old %p)\n",

                sch, p, flow, new, old);

        if (!find_flow(p, flow))

                return -EINVAL;

        if (!new)

                new = &noop_qdisc;

        *old = xchg(&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;

        DPRINTK("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 = PRIV(sch);

        struct atm_flow_data *flow;

        DPRINTK("atm_tc_get(sch %p,[qdisc %p],classid %x)\n", sch, p, classid);

        flow = lookup_flow(sch, classid);

        if (flow)

                flow->ref++;

        DPRINTK("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 = PRIV(sch);

        struct atm_flow_data *flow = (struct atm_flow_data *)cl;

        struct atm_flow_data **prev;

        DPRINTK("atm_tc_put(sch %p,[qdisc %p],flow %p)\n", sch, p, flow);

        if (--flow->ref)

                return;

        DPRINTK("atm_tc_put: destroying\n");

        for (prev = &p->flows; *prev; prev = &(*prev)->next)

                if (*prev == flow)

                        break;

        if (!*prev) {

                printk(KERN_CRIT "atm_tc_put: class %p not found\n", flow);

                return;

        }

        *prev = flow->next;

        DPRINTK("atm_tc_put: qdisc %p\n", flow->q);

        qdisc_destroy(flow->q);

        tcf_destroy_chain(flow->filter_list);

        if (flow->sock) {

                DPRINTK("atm_tc_put: f_count %d\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;

        D2PRINTK("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 int atm_tc_change(struct Qdisc *sch, u32 classid, u32 parent,

                         struct rtattr **tca, unsigned long *arg)

{

        struct atm_qdisc_data *p = PRIV(sch);

        struct atm_flow_data *flow = (struct atm_flow_data *)*arg;

        struct atm_flow_data *excess = NULL;

        struct rtattr *opt = tca[TCA_OPTIONS - 1];

        struct rtattr *tb[TCA_ATM_MAX];

        struct socket *sock;

        int fd, error, hdr_len;

        void *hdr;

        DPRINTK("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 || rtattr_parse_nested(tb, TCA_ATM_MAX, opt))

                return -EINVAL;

        if (!tb[TCA_ATM_FD - 1] || RTA_PAYLOAD(tb[TCA_ATM_FD - 1]) < sizeof(fd))

                return -EINVAL;

        fd = *(int *)RTA_DATA(tb[TCA_ATM_FD - 1]);

        DPRINTK("atm_tc_change: fd %d\n", fd);

        if (tb[TCA_ATM_HDR - 1]) {

                hdr_len = RTA_PAYLOAD(tb[TCA_ATM_HDR - 1]);

                hdr = RTA_DATA(tb[TCA_ATM_HDR - 1]);

        } else {

                hdr_len = RFC1483LLC_LEN;

                hdr = NULL;     /* default LLC/SNAP for IP */

        }

        if (!tb[TCA_ATM_EXCESS - 1])

                excess = NULL;

        else {

                if (RTA_PAYLOAD(tb[TCA_ATM_EXCESS - 1]) != sizeof(u32))

                        return -EINVAL;

                excess = (struct atm_flow_data *)

                        atm_tc_get(sch, *(u32 *)RTA_DATA(tb[TCA_ATM_EXCESS - 1]));

                if (!excess)

                        return -ENOENT;

        }

        DPRINTK("atm_tc_change: type %d, payload %d, hdr_len %d\n",

                opt->rta_type, RTA_PAYLOAD(opt), hdr_len);

        if (!(sock = sockfd_lookup(fd, &error)))

                return error;   /* f_count++ */

        DPRINTK("atm_tc_change: f_count %d\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)) {

                        DPRINTK("atm_tc_change: classid mismatch\n");

                        error = -EINVAL;

                        goto err_out;

                }

                if (find_flow(p, flow)) {

                        error = -EEXIST;

                        goto err_out;

                }

        } else {

                int i;

                unsigned long cl;

                for (i = 1; i < 0x8000; i++) {

                        classid = TC_H_MAKE(sch->handle, 0x8000 | i);

                        if (!(cl = atm_tc_get(sch, classid)))

                                break;

                        atm_tc_put(sch, cl);

                }

        }

        DPRINTK("atm_tc_change: new id %x\n", classid);

        flow = kzalloc(sizeof(struct atm_flow_data) + hdr_len, GFP_KERNEL);

        DPRINTK("atm_tc_change: flow %p\n", flow);

        if (!flow) {

                error = -ENOBUFS;

                goto err_out;

        }

        flow->filter_list = NULL;

        if (!(flow->q = qdisc_create_dflt(sch->dev, &pfifo_qdisc_ops, classid)))

                flow->q = &noop_qdisc;

        DPRINTK("atm_tc_change: qdisc %p\n", flow->q);

        flow->sock = sock;

        flow->vcc = ATM_SD(sock);       /* speedup */

        flow->vcc->user_back = flow;

        DPRINTK("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;

        flow->next = p->link.next;

        p->link.next = flow;

        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 = PRIV(sch);

        struct atm_flow_data *flow = (struct atm_flow_data *)arg;

        DPRINTK("atm_tc_delete(sch %p,[qdisc %p],flow %p)\n", sch, p, flow);

        if (!find_flow(PRIV(sch), flow))

                return -EINVAL;

        if (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) {

                printk(KERN_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 = PRIV(sch);

        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;