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- /*
- * net/sched/cls_tcindex.c Packet classifier for skb->tc_index
- *
- * Written 1998,1999 by Werner Almesberger, EPFL ICA
- */
- #include <linux/module.h>
- #include <linux/types.h>
- #include <linux/kernel.h>
- #include <linux/skbuff.h>
- #include <linux/errno.h>
- #include <linux/slab.h>
- #include <net/act_api.h>
- #include <net/netlink.h>
- #include <net/pkt_cls.h>
- /*
- * Passing parameters to the root seems to be done more awkwardly than really
- * necessary. At least, u32 doesn't seem to use such dirty hacks. To be
- * verified. FIXME.
- */
- #define PERFECT_HASH_THRESHOLD 64 /* use perfect hash if not bigger */
- #define DEFAULT_HASH_SIZE 64 /* optimized for diffserv */
- struct tcindex_filter_result {
- struct tcf_exts exts;
- struct tcf_result res;
- struct rcu_head rcu;
- };
- struct tcindex_filter {
- u16 key;
- struct tcindex_filter_result result;
- struct tcindex_filter __rcu *next;
- struct rcu_head rcu;
- };
- struct tcindex_data {
- struct tcindex_filter_result *perfect; /* perfect hash; NULL if none */
- struct tcindex_filter __rcu **h; /* imperfect hash; */
- struct tcf_proto *tp;
- u16 mask; /* AND key with mask */
- u32 shift; /* shift ANDed key to the right */
- u32 hash; /* hash table size; 0 if undefined */
- u32 alloc_hash; /* allocated size */
- u32 fall_through; /* 0: only classify if explicit match */
- struct rcu_head rcu;
- };
- static inline int
- tcindex_filter_is_set(struct tcindex_filter_result *r)
- {
- return tcf_exts_is_predicative(&r->exts) || r->res.classid;
- }
- static struct tcindex_filter_result *
- tcindex_lookup(struct tcindex_data *p, u16 key)
- {
- if (p->perfect) {
- struct tcindex_filter_result *f = p->perfect + key;
- return tcindex_filter_is_set(f) ? f : NULL;
- } else if (p->h) {
- struct tcindex_filter __rcu **fp;
- struct tcindex_filter *f;
- fp = &p->h[key % p->hash];
- for (f = rcu_dereference_bh_rtnl(*fp);
- f;
- fp = &f->next, f = rcu_dereference_bh_rtnl(*fp))
- if (f->key == key)
- return &f->result;
- }
- return NULL;
- }
- static int tcindex_classify(struct sk_buff *skb, const struct tcf_proto *tp,
- struct tcf_result *res)
- {
- struct tcindex_data *p = rcu_dereference_bh(tp->root);
- struct tcindex_filter_result *f;
- int key = (skb->tc_index & p->mask) >> p->shift;
- pr_debug("tcindex_classify(skb %p,tp %p,res %p),p %p\n",
- skb, tp, res, p);
- f = tcindex_lookup(p, key);
- if (!f) {
- if (!p->fall_through)
- return -1;
- res->classid = TC_H_MAKE(TC_H_MAJ(tp->q->handle), key);
- res->class = 0;
- pr_debug("alg 0x%x\n", res->classid);
- return 0;
- }
- *res = f->res;
- pr_debug("map 0x%x\n", res->classid);
- return tcf_exts_exec(skb, &f->exts, res);
- }
- static unsigned long tcindex_get(struct tcf_proto *tp, u32 handle)
- {
- struct tcindex_data *p = rtnl_dereference(tp->root);
- struct tcindex_filter_result *r;
- pr_debug("tcindex_get(tp %p,handle 0x%08x)\n", tp, handle);
- if (p->perfect && handle >= p->alloc_hash)
- return 0;
- r = tcindex_lookup(p, handle);
- return r && tcindex_filter_is_set(r) ? (unsigned long) r : 0UL;
- }
- static int tcindex_init(struct tcf_proto *tp)
- {
- struct tcindex_data *p;
- pr_debug("tcindex_init(tp %p)\n", tp);
- p = kzalloc(sizeof(struct tcindex_data), GFP_KERNEL);
- if (!p)
- return -ENOMEM;
- p->mask = 0xffff;
- p->hash = DEFAULT_HASH_SIZE;
- p->fall_through = 1;
- rcu_assign_pointer(tp->root, p);
- return 0;
- }
- static void tcindex_destroy_rexts(struct rcu_head *head)
- {
- struct tcindex_filter_result *r;
- r = container_of(head, struct tcindex_filter_result, rcu);
- tcf_exts_destroy(&r->exts);
- }
- static void tcindex_destroy_fexts(struct rcu_head *head)
- {
- struct tcindex_filter *f = container_of(head, struct tcindex_filter, rcu);
- tcf_exts_destroy(&f->result.exts);
- kfree(f);
- }
- static int tcindex_delete(struct tcf_proto *tp, unsigned long arg)
- {
- struct tcindex_data *p = rtnl_dereference(tp->root);
- struct tcindex_filter_result *r = (struct tcindex_filter_result *) arg;
- struct tcindex_filter __rcu **walk;
- struct tcindex_filter *f = NULL;
- pr_debug("tcindex_delete(tp %p,arg 0x%lx),p %p\n", tp, arg, p);
- if (p->perfect) {
- if (!r->res.class)
- return -ENOENT;
- } else {
- int i;
- for (i = 0; i < p->hash; i++) {
- walk = p->h + i;
- for (f = rtnl_dereference(*walk); f;
- walk = &f->next, f = rtnl_dereference(*walk)) {
- if (&f->result == r)
- goto found;
- }
- }
- return -ENOENT;
- found:
- rcu_assign_pointer(*walk, rtnl_dereference(f->next));
- }
- tcf_unbind_filter(tp, &r->res);
- /* all classifiers are required to call tcf_exts_destroy() after rcu
- * grace period, since converted-to-rcu actions are relying on that
- * in cleanup() callback
- */
- if (f)
- call_rcu(&f->rcu, tcindex_destroy_fexts);
- else
- call_rcu(&r->rcu, tcindex_destroy_rexts);
- return 0;
- }
- static int tcindex_destroy_element(struct tcf_proto *tp,
- unsigned long arg,
- struct tcf_walker *walker)
- {
- return tcindex_delete(tp, arg);
- }
- static void __tcindex_destroy(struct rcu_head *head)
- {
- struct tcindex_data *p = container_of(head, struct tcindex_data, rcu);
- kfree(p->perfect);
- kfree(p->h);
- kfree(p);
- }
- static inline int
- valid_perfect_hash(struct tcindex_data *p)
- {
- return p->hash > (p->mask >> p->shift);
- }
- static const struct nla_policy tcindex_policy[TCA_TCINDEX_MAX + 1] = {
- [TCA_TCINDEX_HASH] = { .type = NLA_U32 },
- [TCA_TCINDEX_MASK] = { .type = NLA_U16 },
- [TCA_TCINDEX_SHIFT] = { .type = NLA_U32 },
- [TCA_TCINDEX_FALL_THROUGH] = { .type = NLA_U32 },
- [TCA_TCINDEX_CLASSID] = { .type = NLA_U32 },
- };
- static void tcindex_filter_result_init(struct tcindex_filter_result *r)
- {
- memset(r, 0, sizeof(*r));
- tcf_exts_init(&r->exts, TCA_TCINDEX_ACT, TCA_TCINDEX_POLICE);
- }
- static void __tcindex_partial_destroy(struct rcu_head *head)
- {
- struct tcindex_data *p = container_of(head, struct tcindex_data, rcu);
- kfree(p->perfect);
- kfree(p);
- }
- static int
- tcindex_set_parms(struct net *net, struct tcf_proto *tp, unsigned long base,
- u32 handle, struct tcindex_data *p,
- struct tcindex_filter_result *r, struct nlattr **tb,
- struct nlattr *est, bool ovr)
- {
- int err, balloc = 0;
- struct tcindex_filter_result new_filter_result, *old_r = r;
- struct tcindex_filter_result cr;
- struct tcindex_data *cp, *oldp;
- struct tcindex_filter *f = NULL; /* make gcc behave */
- struct tcf_exts e;
- tcf_exts_init(&e, TCA_TCINDEX_ACT, TCA_TCINDEX_POLICE);
- err = tcf_exts_validate(net, tp, tb, est, &e, ovr);
- if (err < 0)
- return err;
- err = -ENOMEM;
- /* tcindex_data attributes must look atomic to classifier/lookup so
- * allocate new tcindex data and RCU assign it onto root. Keeping
- * perfect hash and hash pointers from old data.
- */
- cp = kzalloc(sizeof(*cp), GFP_KERNEL);
- if (!cp)
- goto errout;
- cp->mask = p->mask;
- cp->shift = p->shift;
- cp->hash = p->hash;
- cp->alloc_hash = p->alloc_hash;
- cp->fall_through = p->fall_through;
- cp->tp = tp;
- if (p->perfect) {
- int i;
- cp->perfect = kmemdup(p->perfect,
- sizeof(*r) * cp->hash, GFP_KERNEL);
- if (!cp->perfect)
- goto errout;
- for (i = 0; i < cp->hash; i++)
- tcf_exts_init(&cp->perfect[i].exts,
- TCA_TCINDEX_ACT, TCA_TCINDEX_POLICE);
- balloc = 1;
- }
- cp->h = p->h;
- tcindex_filter_result_init(&new_filter_result);
- tcindex_filter_result_init(&cr);
- if (old_r)
- cr.res = r->res;
- if (tb[TCA_TCINDEX_HASH])
- cp->hash = nla_get_u32(tb[TCA_TCINDEX_HASH]);
- if (tb[TCA_TCINDEX_MASK])
- cp->mask = nla_get_u16(tb[TCA_TCINDEX_MASK]);
- if (tb[TCA_TCINDEX_SHIFT])
- cp->shift = nla_get_u32(tb[TCA_TCINDEX_SHIFT]);
- err = -EBUSY;
- /* Hash already allocated, make sure that we still meet the
- * requirements for the allocated hash.
- */
- if (cp->perfect) {
- if (!valid_perfect_hash(cp) ||
- cp->hash > cp->alloc_hash)
- goto errout_alloc;
- } else if (cp->h && cp->hash != cp->alloc_hash) {
- goto errout_alloc;
- }
- err = -EINVAL;
- if (tb[TCA_TCINDEX_FALL_THROUGH])
- cp->fall_through = nla_get_u32(tb[TCA_TCINDEX_FALL_THROUGH]);
- if (!cp->hash) {
- /* Hash not specified, use perfect hash if the upper limit
- * of the hashing index is below the threshold.
- */
- if ((cp->mask >> cp->shift) < PERFECT_HASH_THRESHOLD)
- cp->hash = (cp->mask >> cp->shift) + 1;
- else
- cp->hash = DEFAULT_HASH_SIZE;
- }
- if (!cp->perfect && !cp->h)
- cp->alloc_hash = cp->hash;
- /* Note: this could be as restrictive as if (handle & ~(mask >> shift))
- * but then, we'd fail handles that may become valid after some future
- * mask change. While this is extremely unlikely to ever matter,
- * the check below is safer (and also more backwards-compatible).
- */
- if (cp->perfect || valid_perfect_hash(cp))
- if (handle >= cp->alloc_hash)
- goto errout_alloc;
- err = -ENOMEM;
- if (!cp->perfect && !cp->h) {
- if (valid_perfect_hash(cp)) {
- int i;
- cp->perfect = kcalloc(cp->hash, sizeof(*r), GFP_KERNEL);
- if (!cp->perfect)
- goto errout_alloc;
- for (i = 0; i < cp->hash; i++)
- tcf_exts_init(&cp->perfect[i].exts,
- TCA_TCINDEX_ACT,
- TCA_TCINDEX_POLICE);
- balloc = 1;
- } else {
- struct tcindex_filter __rcu **hash;
- hash = kcalloc(cp->hash,
- sizeof(struct tcindex_filter *),
- GFP_KERNEL);
- if (!hash)
- goto errout_alloc;
- cp->h = hash;
- balloc = 2;
- }
- }
- if (cp->perfect)
- r = cp->perfect + handle;
- else
- r = tcindex_lookup(cp, handle) ? : &new_filter_result;
- if (r == &new_filter_result) {
- f = kzalloc(sizeof(*f), GFP_KERNEL);
- if (!f)
- goto errout_alloc;
- f->key = handle;
- tcindex_filter_result_init(&f->result);
- f->next = NULL;
- }
- if (tb[TCA_TCINDEX_CLASSID]) {
- cr.res.classid = nla_get_u32(tb[TCA_TCINDEX_CLASSID]);
- tcf_bind_filter(tp, &cr.res, base);
- }
- if (old_r && old_r != r)
- tcindex_filter_result_init(old_r);
- oldp = p;
- r->res = cr.res;
- tcf_exts_change(tp, &r->exts, &e);
- rcu_assign_pointer(tp->root, cp);
- if (r == &new_filter_result) {
- struct tcindex_filter *nfp;
- struct tcindex_filter __rcu **fp;
- f->result.res = r->res;
- tcf_exts_change(tp, &f->result.exts, &r->exts);
- fp = cp->h + (handle % cp->hash);
- for (nfp = rtnl_dereference(*fp);
- nfp;
- fp = &nfp->next, nfp = rtnl_dereference(*fp))
- ; /* nothing */
- rcu_assign_pointer(*fp, f);
- }
- if (oldp)
- call_rcu(&oldp->rcu, __tcindex_partial_destroy);
- return 0;
- errout_alloc:
- if (balloc == 1)
- kfree(cp->perfect);
- else if (balloc == 2)
- kfree(cp->h);
- errout:
- kfree(cp);
- tcf_exts_destroy(&e);
- return err;
- }
- static int
- tcindex_change(struct net *net, struct sk_buff *in_skb,
- struct tcf_proto *tp, unsigned long base, u32 handle,
- struct nlattr **tca, unsigned long *arg, bool ovr)
- {
- struct nlattr *opt = tca[TCA_OPTIONS];
- struct nlattr *tb[TCA_TCINDEX_MAX + 1];
- struct tcindex_data *p = rtnl_dereference(tp->root);
- struct tcindex_filter_result *r = (struct tcindex_filter_result *) *arg;
- int err;
- pr_debug("tcindex_change(tp %p,handle 0x%08x,tca %p,arg %p),opt %p,"
- "p %p,r %p,*arg 0x%lx\n",
- tp, handle, tca, arg, opt, p, r, arg ? *arg : 0L);
- if (!opt)
- return 0;
- err = nla_parse_nested(tb, TCA_TCINDEX_MAX, opt, tcindex_policy);
- if (err < 0)
- return err;
- return tcindex_set_parms(net, tp, base, handle, p, r, tb,
- tca[TCA_RATE], ovr);
- }
- static void tcindex_walk(struct tcf_proto *tp, struct tcf_walker *walker)
- {
- struct tcindex_data *p = rtnl_dereference(tp->root);
- struct tcindex_filter *f, *next;
- int i;
- pr_debug("tcindex_walk(tp %p,walker %p),p %p\n", tp, walker, p);
- if (p->perfect) {
- for (i = 0; i < p->hash; i++) {
- if (!p->perfect[i].res.class)
- continue;
- if (walker->count >= walker->skip) {
- if (walker->fn(tp,
- (unsigned long) (p->perfect+i), walker)
- < 0) {
- walker->stop = 1;
- return;
- }
- }
- walker->count++;
- }
- }
- if (!p->h)
- return;
- for (i = 0; i < p->hash; i++) {
- for (f = rtnl_dereference(p->h[i]); f; f = next) {
- next = rtnl_dereference(f->next);
- if (walker->count >= walker->skip) {
- if (walker->fn(tp, (unsigned long) &f->result,
- walker) < 0) {
- walker->stop = 1;
- return;
- }
- }
- walker->count++;
- }
- }
- }
- static bool tcindex_destroy(struct tcf_proto *tp, bool force)
- {
- struct tcindex_data *p = rtnl_dereference(tp->root);
- struct tcf_walker walker;
- if (!force)
- return false;
- pr_debug("tcindex_destroy(tp %p),p %p\n", tp, p);
- walker.count = 0;
- walker.skip = 0;
- walker.fn = tcindex_destroy_element;
- tcindex_walk(tp, &walker);
- call_rcu(&p->rcu, __tcindex_destroy);
- return true;
- }
- static int tcindex_dump(struct net *net, struct tcf_proto *tp, unsigned long fh,
- struct sk_buff *skb, struct tcmsg *t)
- {
- struct tcindex_data *p = rtnl_dereference(tp->root);
- struct tcindex_filter_result *r = (struct tcindex_filter_result *) fh;
- struct nlattr *nest;
- pr_debug("tcindex_dump(tp %p,fh 0x%lx,skb %p,t %p),p %p,r %p\n",
- tp, fh, skb, t, p, r);
- pr_debug("p->perfect %p p->h %p\n", p->perfect, p->h);
- nest = nla_nest_start(skb, TCA_OPTIONS);
- if (nest == NULL)
- goto nla_put_failure;
- if (!fh) {
- t->tcm_handle = ~0; /* whatever ... */
- if (nla_put_u32(skb, TCA_TCINDEX_HASH, p->hash) ||
- nla_put_u16(skb, TCA_TCINDEX_MASK, p->mask) ||
- nla_put_u32(skb, TCA_TCINDEX_SHIFT, p->shift) ||
- nla_put_u32(skb, TCA_TCINDEX_FALL_THROUGH, p->fall_through))
- goto nla_put_failure;
- nla_nest_end(skb, nest);
- } else {
- if (p->perfect) {
- t->tcm_handle = r - p->perfect;
- } else {
- struct tcindex_filter *f;
- struct tcindex_filter __rcu **fp;
- int i;
- t->tcm_handle = 0;
- for (i = 0; !t->tcm_handle && i < p->hash; i++) {
- fp = &p->h[i];
- for (f = rtnl_dereference(*fp);
- !t->tcm_handle && f;
- fp = &f->next, f = rtnl_dereference(*fp)) {
- if (&f->result == r)
- t->tcm_handle = f->key;
- }
- }
- }
- pr_debug("handle = %d\n", t->tcm_handle);
- if (r->res.class &&
- nla_put_u32(skb, TCA_TCINDEX_CLASSID, r->res.classid))
- goto nla_put_failure;
- if (tcf_exts_dump(skb, &r->exts) < 0)
- goto nla_put_failure;
- nla_nest_end(skb, nest);
- if (tcf_exts_dump_stats(skb, &r->exts) < 0)
- goto nla_put_failure;
- }
- return skb->len;
- nla_put_failure:
- nla_nest_cancel(skb, nest);
- return -1;
- }
- static struct tcf_proto_ops cls_tcindex_ops __read_mostly = {
- .kind = "tcindex",
- .classify = tcindex_classify,
- .init = tcindex_init,
- .destroy = tcindex_destroy,
- .get = tcindex_get,
- .change = tcindex_change,
- .delete = tcindex_delete,
- .walk = tcindex_walk,
- .dump = tcindex_dump,
- .owner = THIS_MODULE,
- };
- static int __init init_tcindex(void)
- {
- return register_tcf_proto_ops(&cls_tcindex_ops);
- }
- static void __exit exit_tcindex(void)
- {
- unregister_tcf_proto_ops(&cls_tcindex_ops);
- }
- module_init(init_tcindex)
- module_exit(exit_tcindex)
- MODULE_LICENSE("GPL");
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