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alistair23-linux/net/sched/cls_flow.c
Daniel Borkmann d936377414 net, sched: respect rcu grace period on cls destruction 
Roi reported a crash in flower where tp->root was NULL in ->classify()
callbacks. Reason is that in ->destroy() tp->root is set to NULL via
RCU_INIT_POINTER(). It's problematic for some of the classifiers, because
this doesn't respect RCU grace period for them, and as a result, still
outstanding readers from tc_classify() will try to blindly dereference
a NULL tp->root.

The tp->root object is strictly private to the classifier implementation
and holds internal data the core such as tc_ctl_tfilter() doesn't know
about. Within some classifiers, such as cls_bpf, cls_basic, etc, tp->root
is only checked for NULL in ->get() callback, but nowhere else. This is
misleading and seemed to be copied from old classifier code that was not
cleaned up properly. For example, d3fa76ee6b ("[NET_SCHED]: cls_basic:
fix NULL pointer dereference") moved tp->root initialization into ->init()
routine, where before it was part of ->change(), so ->get() had to deal
with tp->root being NULL back then, so that was indeed a valid case, after
d3fa76ee6b, not really anymore. We used to set tp->root to NULL long
ago in ->destroy(), see 47a1a1d4be ("pkt_sched: remove unnecessary xchg()
in packet classifiers"); but the NULLifying was reintroduced with the
RCUification, but it's not correct for every classifier implementation.

In the cases that are fixed here with one exception of cls_cgroup, tp->root
object is allocated and initialized inside ->init() callback, which is always
performed at a point in time after we allocate a new tp, which means tp and
thus tp->root was not globally visible in the tp chain yet (see tc_ctl_tfilter()).
Also, on destruction tp->root is strictly kfree_rcu()'ed in ->destroy()
handler, same for the tp which is kfree_rcu()'ed right when we return
from ->destroy() in tcf_destroy(). This means, the head object's lifetime
for such classifiers is always tied to the tp lifetime. The RCU callback
invocation for the two kfree_rcu() could be out of order, but that's fine
since both are independent.

Dropping the RCU_INIT_POINTER(tp->root, NULL) for these classifiers here
means that 1) we don't need a useless NULL check in fast-path and, 2) that
outstanding readers of that tp in tc_classify() can still execute under
respect with RCU grace period as it is actually expected.

Things that haven't been touched here: cls_fw and cls_route. They each
handle tp->root being NULL in ->classify() path for historic reasons, so
their ->destroy() implementation can stay as is. If someone actually
cares, they could get cleaned up at some point to avoid the test in fast
path. cls_u32 doesn't set tp->root to NULL. For cls_rsvp, I just added a
!head should anyone actually be using/testing it, so it at least aligns with
cls_fw and cls_route. For cls_flower we additionally need to defer rhashtable
destruction (to a sleepable context) after RCU grace period as concurrent
readers might still access it. (Note that in this case we need to hold module
reference to keep work callback address intact, since we only wait on module
unload for all call_rcu()s to finish.)

This fixes one race to bring RCU grace period guarantees back. Next step
as worked on by Cong however is to fix 1e052be69d ("net_sched: destroy
proto tp when all filters are gone") to get the order of unlinking the tp
in tc_ctl_tfilter() for the RTM_DELTFILTER case right by moving
RCU_INIT_POINTER() before tcf_destroy() and let the notification for
removal be done through the prior ->delete() callback. Both are independant
issues. Once we have that right, we can then clean tp->root up for a number
of classifiers by not making them RCU pointers, which requires a new callback
(->uninit) that is triggered from tp's RCU callback, where we just kfree()
tp->root from there.

Fixes: 1f947bf151 ("net: sched: rcu'ify cls_bpf")
Fixes: 9888faefe1 ("net: sched: cls_basic use RCU")
Fixes: 70da9f0bf9 ("net: sched: cls_flow use RCU")
Fixes: 77b9900ef5 ("tc: introduce Flower classifier")
Fixes: bf3994d2ed ("net/sched: introduce Match-all classifier")
Fixes: 952313bd62 ("net: sched: cls_cgroup use RCU")
Reported-by: Roi Dayan <roid@mellanox.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Cc: Cong Wang <xiyou.wangcong@gmail.com>
Cc: John Fastabend <john.fastabend@gmail.com>
Cc: Roi Dayan <roid@mellanox.com>
Cc: Jiri Pirko <jiri@mellanox.com>
Acked-by: John Fastabend <john.r.fastabend@intel.com>
Acked-by: Cong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2016-11-28 10:47:35 -05:00

721 lines
16 KiB
C
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/*
* net/sched/cls_flow.c Generic flow classifier
*
* Copyright (c) 2007, 2008 Patrick McHardy <kaber@trash.net>
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version 2
* of the License, or (at your option) any later version.
*/
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/list.h>
#include <linux/jhash.h>
#include <linux/random.h>
#include <linux/pkt_cls.h>
#include <linux/skbuff.h>
#include <linux/in.h>
#include <linux/ip.h>
#include <linux/ipv6.h>
#include <linux/if_vlan.h>
#include <linux/slab.h>
#include <linux/module.h>
#include <net/inet_sock.h>
#include <net/pkt_cls.h>
#include <net/ip.h>
#include <net/route.h>
#include <net/flow_dissector.h>
#if IS_ENABLED(CONFIG_NF_CONNTRACK)
#include <net/netfilter/nf_conntrack.h>
#endif
struct flow_head {
struct list_head filters;
struct rcu_head rcu;
};
struct flow_filter {
struct list_head list;
struct tcf_exts exts;
struct tcf_ematch_tree ematches;
struct tcf_proto *tp;
struct timer_list perturb_timer;
u32 perturb_period;
u32 handle;
u32 nkeys;
u32 keymask;
u32 mode;
u32 mask;
u32 xor;
u32 rshift;
u32 addend;
u32 divisor;
u32 baseclass;
u32 hashrnd;
struct rcu_head rcu;
};
static inline u32 addr_fold(void *addr)
{
unsigned long a = (unsigned long)addr;
return (a & 0xFFFFFFFF) ^ (BITS_PER_LONG > 32 ? a >> 32 : 0);
}
static u32 flow_get_src(const struct sk_buff *skb, const struct flow_keys *flow)
{
__be32 src = flow_get_u32_src(flow);
if (src)
return ntohl(src);
return addr_fold(skb->sk);
}
static u32 flow_get_dst(const struct sk_buff *skb, const struct flow_keys *flow)
{
__be32 dst = flow_get_u32_dst(flow);
if (dst)
return ntohl(dst);
return addr_fold(skb_dst(skb)) ^ (__force u16) tc_skb_protocol(skb);
}
static u32 flow_get_proto(const struct sk_buff *skb,
const struct flow_keys *flow)
{
return flow->basic.ip_proto;
}
static u32 flow_get_proto_src(const struct sk_buff *skb,
const struct flow_keys *flow)
{
if (flow->ports.ports)
return ntohs(flow->ports.src);
return addr_fold(skb->sk);
}
static u32 flow_get_proto_dst(const struct sk_buff *skb,
const struct flow_keys *flow)
{
if (flow->ports.ports)
return ntohs(flow->ports.dst);
return addr_fold(skb_dst(skb)) ^ (__force u16) tc_skb_protocol(skb);
}
static u32 flow_get_iif(const struct sk_buff *skb)
{
return skb->skb_iif;
}
static u32 flow_get_priority(const struct sk_buff *skb)
{
return skb->priority;
}
static u32 flow_get_mark(const struct sk_buff *skb)
{
return skb->mark;
}
static u32 flow_get_nfct(const struct sk_buff *skb)
{
#if IS_ENABLED(CONFIG_NF_CONNTRACK)
return addr_fold(skb->nfct);
#else
return 0;
#endif
}
#if IS_ENABLED(CONFIG_NF_CONNTRACK)
#define CTTUPLE(skb, member) \
({ \
enum ip_conntrack_info ctinfo; \
const struct nf_conn *ct = nf_ct_get(skb, &ctinfo); \
if (ct == NULL) \
goto fallback; \
ct->tuplehash[CTINFO2DIR(ctinfo)].tuple.member; \
})
#else
#define CTTUPLE(skb, member) \
({ \
goto fallback; \
0; \
})
#endif
static u32 flow_get_nfct_src(const struct sk_buff *skb,
const struct flow_keys *flow)
{
switch (tc_skb_protocol(skb)) {
case htons(ETH_P_IP):
return ntohl(CTTUPLE(skb, src.u3.ip));
case htons(ETH_P_IPV6):
return ntohl(CTTUPLE(skb, src.u3.ip6[3]));
}
fallback:
return flow_get_src(skb, flow);
}
static u32 flow_get_nfct_dst(const struct sk_buff *skb,
const struct flow_keys *flow)
{
switch (tc_skb_protocol(skb)) {
case htons(ETH_P_IP):
return ntohl(CTTUPLE(skb, dst.u3.ip));
case htons(ETH_P_IPV6):
return ntohl(CTTUPLE(skb, dst.u3.ip6[3]));
}
fallback:
return flow_get_dst(skb, flow);
}
static u32 flow_get_nfct_proto_src(const struct sk_buff *skb,
const struct flow_keys *flow)
{
return ntohs(CTTUPLE(skb, src.u.all));
fallback:
return flow_get_proto_src(skb, flow);
}
static u32 flow_get_nfct_proto_dst(const struct sk_buff *skb,
const struct flow_keys *flow)
{
return ntohs(CTTUPLE(skb, dst.u.all));
fallback:
return flow_get_proto_dst(skb, flow);
}
static u32 flow_get_rtclassid(const struct sk_buff *skb)
{
#ifdef CONFIG_IP_ROUTE_CLASSID
if (skb_dst(skb))
return skb_dst(skb)->tclassid;
#endif
return 0;
}
static u32 flow_get_skuid(const struct sk_buff *skb)
{
struct sock *sk = skb_to_full_sk(skb);
if (sk && sk->sk_socket && sk->sk_socket->file) {
kuid_t skuid = sk->sk_socket->file->f_cred->fsuid;
return from_kuid(&init_user_ns, skuid);
}
return 0;
}
static u32 flow_get_skgid(const struct sk_buff *skb)
{
struct sock *sk = skb_to_full_sk(skb);
if (sk && sk->sk_socket && sk->sk_socket->file) {
kgid_t skgid = sk->sk_socket->file->f_cred->fsgid;
return from_kgid(&init_user_ns, skgid);
}
return 0;
}
static u32 flow_get_vlan_tag(const struct sk_buff *skb)
{
u16 uninitialized_var(tag);
if (vlan_get_tag(skb, &tag) < 0)
return 0;
return tag & VLAN_VID_MASK;
}
static u32 flow_get_rxhash(struct sk_buff *skb)
{
return skb_get_hash(skb);
}
static u32 flow_key_get(struct sk_buff *skb, int key, struct flow_keys *flow)
{
switch (key) {
case FLOW_KEY_SRC:
return flow_get_src(skb, flow);
case FLOW_KEY_DST:
return flow_get_dst(skb, flow);
case FLOW_KEY_PROTO:
return flow_get_proto(skb, flow);
case FLOW_KEY_PROTO_SRC:
return flow_get_proto_src(skb, flow);
case FLOW_KEY_PROTO_DST:
return flow_get_proto_dst(skb, flow);
case FLOW_KEY_IIF:
return flow_get_iif(skb);
case FLOW_KEY_PRIORITY:
return flow_get_priority(skb);
case FLOW_KEY_MARK:
return flow_get_mark(skb);
case FLOW_KEY_NFCT:
return flow_get_nfct(skb);
case FLOW_KEY_NFCT_SRC:
return flow_get_nfct_src(skb, flow);
case FLOW_KEY_NFCT_DST:
return flow_get_nfct_dst(skb, flow);
case FLOW_KEY_NFCT_PROTO_SRC:
return flow_get_nfct_proto_src(skb, flow);
case FLOW_KEY_NFCT_PROTO_DST:
return flow_get_nfct_proto_dst(skb, flow);
case FLOW_KEY_RTCLASSID:
return flow_get_rtclassid(skb);
case FLOW_KEY_SKUID:
return flow_get_skuid(skb);
case FLOW_KEY_SKGID:
return flow_get_skgid(skb);
case FLOW_KEY_VLAN_TAG:
return flow_get_vlan_tag(skb);
case FLOW_KEY_RXHASH:
return flow_get_rxhash(skb);
default:
WARN_ON(1);
return 0;
}
}
#define FLOW_KEYS_NEEDED ((1 << FLOW_KEY_SRC) | \
(1 << FLOW_KEY_DST) | \
(1 << FLOW_KEY_PROTO) | \
(1 << FLOW_KEY_PROTO_SRC) | \
(1 << FLOW_KEY_PROTO_DST) | \
(1 << FLOW_KEY_NFCT_SRC) | \
(1 << FLOW_KEY_NFCT_DST) | \
(1 << FLOW_KEY_NFCT_PROTO_SRC) | \
(1 << FLOW_KEY_NFCT_PROTO_DST))
static int flow_classify(struct sk_buff *skb, const struct tcf_proto *tp,
struct tcf_result *res)
{
struct flow_head *head = rcu_dereference_bh(tp->root);
struct flow_filter *f;
u32 keymask;
u32 classid;
unsigned int n, key;
int r;
list_for_each_entry_rcu(f, &head->filters, list) {
u32 keys[FLOW_KEY_MAX + 1];
struct flow_keys flow_keys;
if (!tcf_em_tree_match(skb, &f->ematches, NULL))
continue;
keymask = f->keymask;
if (keymask & FLOW_KEYS_NEEDED)
skb_flow_dissect_flow_keys(skb, &flow_keys, 0);
for (n = 0; n < f->nkeys; n++) {
key = ffs(keymask) - 1;
keymask &= ~(1 << key);
keys[n] = flow_key_get(skb, key, &flow_keys);
}
if (f->mode == FLOW_MODE_HASH)
classid = jhash2(keys, f->nkeys, f->hashrnd);
else {
classid = keys[0];
classid = (classid & f->mask) ^ f->xor;
classid = (classid >> f->rshift) + f->addend;
}
if (f->divisor)
classid %= f->divisor;
res->class = 0;
res->classid = TC_H_MAKE(f->baseclass, f->baseclass + classid);
r = tcf_exts_exec(skb, &f->exts, res);
if (r < 0)
continue;
return r;
}
return -1;
}
static void flow_perturbation(unsigned long arg)
{
struct flow_filter *f = (struct flow_filter *)arg;
get_random_bytes(&f->hashrnd, 4);
if (f->perturb_period)
mod_timer(&f->perturb_timer, jiffies + f->perturb_period);
}
static const struct nla_policy flow_policy[TCA_FLOW_MAX + 1] = {
[TCA_FLOW_KEYS] = { .type = NLA_U32 },
[TCA_FLOW_MODE] = { .type = NLA_U32 },
[TCA_FLOW_BASECLASS] = { .type = NLA_U32 },
[TCA_FLOW_RSHIFT] = { .type = NLA_U32 },
[TCA_FLOW_ADDEND] = { .type = NLA_U32 },
[TCA_FLOW_MASK] = { .type = NLA_U32 },
[TCA_FLOW_XOR] = { .type = NLA_U32 },
[TCA_FLOW_DIVISOR] = { .type = NLA_U32 },
[TCA_FLOW_ACT] = { .type = NLA_NESTED },
[TCA_FLOW_POLICE] = { .type = NLA_NESTED },
[TCA_FLOW_EMATCHES] = { .type = NLA_NESTED },
[TCA_FLOW_PERTURB] = { .type = NLA_U32 },
};
static void flow_destroy_filter(struct rcu_head *head)
{
struct flow_filter *f = container_of(head, struct flow_filter, rcu);
del_timer_sync(&f->perturb_timer);
tcf_exts_destroy(&f->exts);
tcf_em_tree_destroy(&f->ematches);
kfree(f);
}
static int flow_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 flow_head *head = rtnl_dereference(tp->root);
struct flow_filter *fold, *fnew;
struct nlattr *opt = tca[TCA_OPTIONS];
struct nlattr *tb[TCA_FLOW_MAX + 1];
struct tcf_exts e;
struct tcf_ematch_tree t;
unsigned int nkeys = 0;
unsigned int perturb_period = 0;
u32 baseclass = 0;
u32 keymask = 0;
u32 mode;
int err;
if (opt == NULL)
return -EINVAL;
err = nla_parse_nested(tb, TCA_FLOW_MAX, opt, flow_policy);
if (err < 0)
return err;
if (tb[TCA_FLOW_BASECLASS]) {
baseclass = nla_get_u32(tb[TCA_FLOW_BASECLASS]);
if (TC_H_MIN(baseclass) == 0)
return -EINVAL;
}
if (tb[TCA_FLOW_KEYS]) {
keymask = nla_get_u32(tb[TCA_FLOW_KEYS]);
nkeys = hweight32(keymask);
if (nkeys == 0)
return -EINVAL;
if (fls(keymask) - 1 > FLOW_KEY_MAX)
return -EOPNOTSUPP;
if ((keymask & (FLOW_KEY_SKUID|FLOW_KEY_SKGID)) &&
sk_user_ns(NETLINK_CB(in_skb).sk) != &init_user_ns)
return -EOPNOTSUPP;
}
err = tcf_exts_init(&e, TCA_FLOW_ACT, TCA_FLOW_POLICE);
if (err < 0)
goto err1;
err = tcf_exts_validate(net, tp, tb, tca[TCA_RATE], &e, ovr);
if (err < 0)
goto err1;
err = tcf_em_tree_validate(tp, tb[TCA_FLOW_EMATCHES], &t);
if (err < 0)
goto err1;
err = -ENOBUFS;
fnew = kzalloc(sizeof(*fnew), GFP_KERNEL);
if (!fnew)
goto err2;
err = tcf_exts_init(&fnew->exts, TCA_FLOW_ACT, TCA_FLOW_POLICE);
if (err < 0)
goto err3;
fold = (struct flow_filter *)*arg;
if (fold) {
err = -EINVAL;
if (fold->handle != handle && handle)
goto err3;
/* Copy fold into fnew */
fnew->tp = fold->tp;
fnew->handle = fold->handle;
fnew->nkeys = fold->nkeys;
fnew->keymask = fold->keymask;
fnew->mode = fold->mode;
fnew->mask = fold->mask;
fnew->xor = fold->xor;
fnew->rshift = fold->rshift;
fnew->addend = fold->addend;
fnew->divisor = fold->divisor;
fnew->baseclass = fold->baseclass;
fnew->hashrnd = fold->hashrnd;
mode = fold->mode;
if (tb[TCA_FLOW_MODE])
mode = nla_get_u32(tb[TCA_FLOW_MODE]);
if (mode != FLOW_MODE_HASH && nkeys > 1)
goto err3;
if (mode == FLOW_MODE_HASH)
perturb_period = fold->perturb_period;
if (tb[TCA_FLOW_PERTURB]) {
if (mode != FLOW_MODE_HASH)
goto err3;
perturb_period = nla_get_u32(tb[TCA_FLOW_PERTURB]) * HZ;
}
} else {
err = -EINVAL;
if (!handle)
goto err3;
if (!tb[TCA_FLOW_KEYS])
goto err3;
mode = FLOW_MODE_MAP;
if (tb[TCA_FLOW_MODE])
mode = nla_get_u32(tb[TCA_FLOW_MODE]);
if (mode != FLOW_MODE_HASH && nkeys > 1)
goto err3;
if (tb[TCA_FLOW_PERTURB]) {
if (mode != FLOW_MODE_HASH)
goto err3;
perturb_period = nla_get_u32(tb[TCA_FLOW_PERTURB]) * HZ;
}
if (TC_H_MAJ(baseclass) == 0)
baseclass = TC_H_MAKE(tp->q->handle, baseclass);
if (TC_H_MIN(baseclass) == 0)
baseclass = TC_H_MAKE(baseclass, 1);
fnew->handle = handle;
fnew->mask = ~0U;
fnew->tp = tp;
get_random_bytes(&fnew->hashrnd, 4);
}
fnew->perturb_timer.function = flow_perturbation;
fnew->perturb_timer.data = (unsigned long)fnew;
init_timer_deferrable(&fnew->perturb_timer);
tcf_exts_change(tp, &fnew->exts, &e);
tcf_em_tree_change(tp, &fnew->ematches, &t);
netif_keep_dst(qdisc_dev(tp->q));
if (tb[TCA_FLOW_KEYS]) {
fnew->keymask = keymask;
fnew->nkeys = nkeys;
}
fnew->mode = mode;
if (tb[TCA_FLOW_MASK])
fnew->mask = nla_get_u32(tb[TCA_FLOW_MASK]);
if (tb[TCA_FLOW_XOR])
fnew->xor = nla_get_u32(tb[TCA_FLOW_XOR]);
if (tb[TCA_FLOW_RSHIFT])
fnew->rshift = nla_get_u32(tb[TCA_FLOW_RSHIFT]);
if (tb[TCA_FLOW_ADDEND])
fnew->addend = nla_get_u32(tb[TCA_FLOW_ADDEND]);
if (tb[TCA_FLOW_DIVISOR])
fnew->divisor = nla_get_u32(tb[TCA_FLOW_DIVISOR]);
if (baseclass)
fnew->baseclass = baseclass;
fnew->perturb_period = perturb_period;
if (perturb_period)
mod_timer(&fnew->perturb_timer, jiffies + perturb_period);
if (*arg == 0)
list_add_tail_rcu(&fnew->list, &head->filters);
else
list_replace_rcu(&fold->list, &fnew->list);
*arg = (unsigned long)fnew;
if (fold)
call_rcu(&fold->rcu, flow_destroy_filter);
return 0;
err3:
tcf_exts_destroy(&fnew->exts);
err2:
tcf_em_tree_destroy(&t);
kfree(fnew);
err1:
tcf_exts_destroy(&e);
return err;
}
static int flow_delete(struct tcf_proto *tp, unsigned long arg)
{
struct flow_filter *f = (struct flow_filter *)arg;
list_del_rcu(&f->list);
call_rcu(&f->rcu, flow_destroy_filter);
return 0;
}
static int flow_init(struct tcf_proto *tp)
{
struct flow_head *head;
head = kzalloc(sizeof(*head), GFP_KERNEL);
if (head == NULL)
return -ENOBUFS;
INIT_LIST_HEAD(&head->filters);
rcu_assign_pointer(tp->root, head);
return 0;
}
static bool flow_destroy(struct tcf_proto *tp, bool force)
{
struct flow_head *head = rtnl_dereference(tp->root);
struct flow_filter *f, *next;
if (!force && !list_empty(&head->filters))
return false;
list_for_each_entry_safe(f, next, &head->filters, list) {
list_del_rcu(&f->list);
call_rcu(&f->rcu, flow_destroy_filter);
}
kfree_rcu(head, rcu);
return true;
}
static unsigned long flow_get(struct tcf_proto *tp, u32 handle)
{
struct flow_head *head = rtnl_dereference(tp->root);
struct flow_filter *f;
list_for_each_entry(f, &head->filters, list)
if (f->handle == handle)
return (unsigned long)f;
return 0;
}
static int flow_dump(struct net *net, struct tcf_proto *tp, unsigned long fh,
struct sk_buff *skb, struct tcmsg *t)
{
struct flow_filter *f = (struct flow_filter *)fh;
struct nlattr *nest;
if (f == NULL)
return skb->len;
t->tcm_handle = f->handle;
nest = nla_nest_start(skb, TCA_OPTIONS);
if (nest == NULL)
goto nla_put_failure;
if (nla_put_u32(skb, TCA_FLOW_KEYS, f->keymask) ||
nla_put_u32(skb, TCA_FLOW_MODE, f->mode))
goto nla_put_failure;
if (f->mask != ~0 || f->xor != 0) {
if (nla_put_u32(skb, TCA_FLOW_MASK, f->mask) ||
nla_put_u32(skb, TCA_FLOW_XOR, f->xor))
goto nla_put_failure;
}
if (f->rshift &&
nla_put_u32(skb, TCA_FLOW_RSHIFT, f->rshift))
goto nla_put_failure;
if (f->addend &&
nla_put_u32(skb, TCA_FLOW_ADDEND, f->addend))
goto nla_put_failure;
if (f->divisor &&
nla_put_u32(skb, TCA_FLOW_DIVISOR, f->divisor))
goto nla_put_failure;
if (f->baseclass &&
nla_put_u32(skb, TCA_FLOW_BASECLASS, f->baseclass))
goto nla_put_failure;
if (f->perturb_period &&
nla_put_u32(skb, TCA_FLOW_PERTURB, f->perturb_period / HZ))
goto nla_put_failure;
if (tcf_exts_dump(skb, &f->exts) < 0)
goto nla_put_failure;
#ifdef CONFIG_NET_EMATCH
if (f->ematches.hdr.nmatches &&
tcf_em_tree_dump(skb, &f->ematches, TCA_FLOW_EMATCHES) < 0)
goto nla_put_failure;
#endif
nla_nest_end(skb, nest);
if (tcf_exts_dump_stats(skb, &f->exts) < 0)
goto nla_put_failure;
return skb->len;
nla_put_failure:
nla_nest_cancel(skb, nest);
return -1;
}
static void flow_walk(struct tcf_proto *tp, struct tcf_walker *arg)
{
struct flow_head *head = rtnl_dereference(tp->root);
struct flow_filter *f;
list_for_each_entry(f, &head->filters, list) {
if (arg->count < arg->skip)
goto skip;
if (arg->fn(tp, (unsigned long)f, arg) < 0) {
arg->stop = 1;
break;
}
skip:
arg->count++;
}
}
static struct tcf_proto_ops cls_flow_ops __read_mostly = {
.kind = "flow",
.classify = flow_classify,
.init = flow_init,
.destroy = flow_destroy,
.change = flow_change,
.delete = flow_delete,
.get = flow_get,
.dump = flow_dump,
.walk = flow_walk,
.owner = THIS_MODULE,
};
static int __init cls_flow_init(void)
{
return register_tcf_proto_ops(&cls_flow_ops);
}
static void __exit cls_flow_exit(void)
{
unregister_tcf_proto_ops(&cls_flow_ops);
}
module_init(cls_flow_init);
module_exit(cls_flow_exit);
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Patrick McHardy <kaber@trash.net>");
MODULE_DESCRIPTION("TC flow classifier");
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