cregit-Linux how code gets into the kernel

Release 4.8 net/sched/sch_atm.c

Directory: net/sched
/* 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; }


patrick mchardypatrick mchardy2137.50%120.00%
david s. millerdavid s. miller1832.14%240.00%
stephen hemmingerstephen hemminger11.79%120.00%

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; }


patrick mchardypatrick mchardy65.26%240.00%
david s. millerdavid s. miller43.51%120.00%
stephen hemmingerstephen hemminger21.75%120.00%

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; }


stephen hemmingerstephen hemminger12.13%150.00%

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; }


stephen hemmingerstephen hemminger34.05%133.33%
patrick mchardypatrick mchardy11.35%133.33%

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.) */ }


stephen hemmingerstephen hemminger53.01%114.29%
patrick mchardypatrick mchardy42.41%228.57%
david s. millerdavid s. miller42.41%114.29%
al viroal viro10.60%114.29%

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); }


stephen hemmingerstephen hemminger11.69%133.33%

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; }


patrick mchardypatrick mchardy314.37%635.29%
stephen hemmingerstephen hemminger273.81%15.88%
david s. millerdavid s. miller121.69%211.76%
john fastabendjohn fastabend40.56%15.88%
chas williamschas williams20.28%15.88%
al viroal viro10.14%15.88%
vignesh babuvignesh babu10.14%15.88%

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; }


david s. millerdavid s. miller43.10%116.67%
john fastabendjohn fastabend32.33%116.67%
stephen hemmingerstephen hemminger21.55%116.67%
patrick mchardypatrick mchardy10.78%116.67%
eric dumazeteric dumazet10.78%116.67%

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++; } }


david s. millerdavid s. miller99.00%133.33%
stephen hemmingerstephen hemminger22.00%133.33%

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; }


stephen hemmingerstephen hemminger22.99%133.33%
john fastabendjohn fastabend11.49%133.33%

/* --------------------------- Qdisc operations ---------------------------- */
static int atm_tc_enqueue(struct sk_buff *skb, struct Qdisc *sch, struct sk_buff **to_free) { struct atm_qdisc_data *p = qdisc_priv(sch); struct atm_flow_data *flow; struct tcf_result res; int result; int ret = NET_XMIT_SUCCESS | __NET_XMIT_BYPASS; pr_debug("atm_tc_enqueue(skb %p,sch %p,[qdisc %p])\n", skb, sch, p); result = TC_ACT_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: __qdisc_drop(skb, to_free); return NET_XMIT_SUCCESS | __NET_XMIT_STOLEN; case TC_ACT_SHOT: __qdisc_drop(skb, to_free); goto drop; case TC_ACT_RECLASSIFY: if (flow->excess) flow = flow->excess; else ATM_SKB(skb)->atm_options |= ATM_ATMOPT_CLP; break; } #endif } ret = qdisc_enqueue(skb, flow->q, to_free); 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; }


patrick mchardypatrick mchardy5915.32%315.79%
david s. millerdavid s. miller266.75%15.26%
john fastabendjohn fastabend184.68%210.53%
eric dumazeteric dumazet164.16%210.53%
jarek poplawskijarek poplawski143.64%210.53%
stephen hemmingerstephen hemminger61.56%15.26%
daniel borkmanndaniel borkmann30.78%15.26%
florian westphalflorian westphal30.78%15.26%
ben greearben greear20.52%15.26%
americo wangamerico wang20.52%15.26%
jussi kivilinnajussi kivilinna10.26%15.26%
thomas grafthomas graf10.26%15.26%

/* * 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); } } }


eric dumazeteric dumazet176.05%17.69%
david s. millerdavid s. miller165.69%17.69%
jarek poplawskijarek poplawski155.34%215.38%
arnaldo carvalho de meloarnaldo carvalho de melo103.56%323.08%
stephen hemmingerstephen hemminger41.42%17.69%
chas williamschas williams10.36%17.69%
steven colesteven cole10.36%17.69%

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; }


stephen hemmingerstephen hemminger22.86%125.00%
jarek poplawskijarek poplawski11.43%125.00%

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); }


jarek poplawskijarek poplawski50100.00%1100.00%

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; }


david s. millerdavid s. miller2915.43%225.00%
stephen hemmingerstephen hemminger126.38%112.50%
patrick mchardypatrick mchardy52.66%225.00%
john fastabendjohn fastabend42.13%112.50%

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; }


david s. millerdavid s. miller813.79%133.33%
stephen hemmingerstephen hemminger23.45%133.33%

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); }


david s. millerdavid s. miller2120.19%112.50%
patrick mchardypatrick mchardy54.81%337.50%
stephen hemmingerstephen hemminger21.92%112.50%
eric dumazeteric dumazet10.96%112.50%

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;