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net: sched: introduce helpers to work with filter chains
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Introduce struct tcf_chain object and set of helpers around it. Wraps up
insertion, deletion and search in the filter chain.

Signed-off-by: Jiri Pirko <jiri@mellanox.com>
Acked-by: Jamal Hadi Salim <jhs@mojatatu.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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Jiri Pirko authored and David S. Miller committed May 17, 2017
1 parent 7961973 commit 2190d1d
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Showing 2 changed files with 113 additions and 42 deletions.
7 changes: 6 additions & 1 deletion include/net/sch_generic.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -248,10 +248,15 @@ struct qdisc_skb_cb {
unsigned char data[QDISC_CB_PRIV_LEN];
};

struct tcf_block {
struct tcf_chain {
struct tcf_proto __rcu *filter_chain;
struct tcf_proto __rcu **p_filter_chain;
};

struct tcf_block {
struct tcf_chain *chain;
};

static inline void qdisc_cb_private_validate(const struct sk_buff *skb, int sz)
{
struct qdisc_skb_cb *qcb;
Expand Down
148 changes: 107 additions & 41 deletions net/sched/cls_api.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -106,13 +106,12 @@ static int tfilter_notify(struct net *net, struct sk_buff *oskb,

static void tfilter_notify_chain(struct net *net, struct sk_buff *oskb,
struct nlmsghdr *n,
struct tcf_proto __rcu **chain, int event)
struct tcf_chain *chain, int event)
{
struct tcf_proto __rcu **it_chain;
struct tcf_proto *tp;

for (it_chain = chain; (tp = rtnl_dereference(*it_chain)) != NULL;
it_chain = &tp->next)
for (tp = rtnl_dereference(chain->filter_chain);
tp; tp = rtnl_dereference(tp->next))
tfilter_notify(net, oskb, n, tp, 0, event, false);
}

Expand Down Expand Up @@ -187,34 +186,57 @@ static void tcf_proto_destroy(struct tcf_proto *tp)
kfree_rcu(tp, rcu);
}

static void tcf_chain_destroy(struct tcf_proto __rcu **fl)
static struct tcf_chain *tcf_chain_create(void)
{
return kzalloc(sizeof(struct tcf_chain), GFP_KERNEL);
}

static void tcf_chain_destroy(struct tcf_chain *chain)
{
struct tcf_proto *tp;

while ((tp = rtnl_dereference(*fl)) != NULL) {
RCU_INIT_POINTER(*fl, tp->next);
while ((tp = rtnl_dereference(chain->filter_chain)) != NULL) {
RCU_INIT_POINTER(chain->filter_chain, tp->next);
tcf_proto_destroy(tp);
}
kfree(chain);
}

static void
tcf_chain_filter_chain_ptr_set(struct tcf_chain *chain,
struct tcf_proto __rcu **p_filter_chain)
{
chain->p_filter_chain = p_filter_chain;
}

int tcf_block_get(struct tcf_block **p_block,
struct tcf_proto __rcu **p_filter_chain)
{
struct tcf_block *block = kzalloc(sizeof(*block), GFP_KERNEL);
int err;

if (!block)
return -ENOMEM;
block->p_filter_chain = p_filter_chain;
block->chain = tcf_chain_create();
if (!block->chain) {
err = -ENOMEM;
goto err_chain_create;
}
tcf_chain_filter_chain_ptr_set(block->chain, p_filter_chain);
*p_block = block;
return 0;

err_chain_create:
kfree(block);
return err;
}
EXPORT_SYMBOL(tcf_block_get);

void tcf_block_put(struct tcf_block *block)
{
if (!block)
return;
tcf_chain_destroy(block->p_filter_chain);
tcf_chain_destroy(block->chain);
kfree(block);
}
EXPORT_SYMBOL(tcf_block_put);
Expand Down Expand Up @@ -267,6 +289,65 @@ int tcf_classify(struct sk_buff *skb, const struct tcf_proto *tp,
}
EXPORT_SYMBOL(tcf_classify);

struct tcf_chain_info {
struct tcf_proto __rcu **pprev;
struct tcf_proto __rcu *next;
};

static struct tcf_proto *tcf_chain_tp_prev(struct tcf_chain_info *chain_info)
{
return rtnl_dereference(*chain_info->pprev);
}

static void tcf_chain_tp_insert(struct tcf_chain *chain,
struct tcf_chain_info *chain_info,
struct tcf_proto *tp)
{
if (chain->p_filter_chain &&
*chain_info->pprev == chain->filter_chain)
*chain->p_filter_chain = tp;
RCU_INIT_POINTER(tp->next, tcf_chain_tp_prev(chain_info));
rcu_assign_pointer(*chain_info->pprev, tp);
}

static void tcf_chain_tp_remove(struct tcf_chain *chain,
struct tcf_chain_info *chain_info,
struct tcf_proto *tp)
{
struct tcf_proto *next = rtnl_dereference(chain_info->next);

if (chain->p_filter_chain && tp == chain->filter_chain)
*chain->p_filter_chain = next;
RCU_INIT_POINTER(*chain_info->pprev, next);
}

static struct tcf_proto *tcf_chain_tp_find(struct tcf_chain *chain,
struct tcf_chain_info *chain_info,
u32 protocol, u32 prio,
bool prio_allocate)
{
struct tcf_proto **pprev;
struct tcf_proto *tp;

/* Check the chain for existence of proto-tcf with this priority */
for (pprev = &chain->filter_chain;
(tp = rtnl_dereference(*pprev)); pprev = &tp->next) {
if (tp->prio >= prio) {
if (tp->prio == prio) {
if (prio_allocate ||
(tp->protocol != protocol && protocol))
return ERR_PTR(-EINVAL);
} else {
tp = NULL;
}
break;
}
}
chain_info->pprev = pprev;
chain_info->next = tp ? tp->next : NULL;
return tp;
}

/* Add/change/delete/get a filter node */

static int tc_ctl_tfilter(struct sk_buff *skb, struct nlmsghdr *n,
Expand All @@ -281,10 +362,9 @@ static int tc_ctl_tfilter(struct sk_buff *skb, struct nlmsghdr *n,
u32 parent;
struct net_device *dev;
struct Qdisc *q;
struct tcf_proto __rcu **back;
struct tcf_proto __rcu **chain;
struct tcf_chain_info chain_info;
struct tcf_chain *chain;
struct tcf_block *block;
struct tcf_proto *next;
struct tcf_proto *tp;
const struct Qdisc_class_ops *cops;
unsigned long cl;
Expand Down Expand Up @@ -369,7 +449,7 @@ static int tc_ctl_tfilter(struct sk_buff *skb, struct nlmsghdr *n,
err = -EINVAL;
goto errout;
}
chain = block->p_filter_chain;
chain = block->chain;

if (n->nlmsg_type == RTM_DELTFILTER && prio == 0) {
tfilter_notify_chain(net, skb, n, chain, RTM_DELTFILTER);
Expand All @@ -378,22 +458,11 @@ static int tc_ctl_tfilter(struct sk_buff *skb, struct nlmsghdr *n,
goto errout;
}

/* Check the chain for existence of proto-tcf with this priority */
for (back = chain;
(tp = rtnl_dereference(*back)) != NULL;
back = &tp->next) {
if (tp->prio >= prio) {
if (tp->prio == prio) {
if (prio_allocate ||
(tp->protocol != protocol && protocol)) {
err = -EINVAL;
goto errout;
}
} else {
tp = NULL;
}
break;
}
tp = tcf_chain_tp_find(chain, &chain_info, protocol,
prio, prio_allocate);
if (IS_ERR(tp)) {
err = PTR_ERR(tp);
goto errout;
}

if (tp == NULL) {
Expand All @@ -411,7 +480,7 @@ static int tc_ctl_tfilter(struct sk_buff *skb, struct nlmsghdr *n,
}

if (prio_allocate)
prio = tcf_auto_prio(rtnl_dereference(*back));
prio = tcf_auto_prio(tcf_chain_tp_prev(&chain_info));

tp = tcf_proto_create(nla_data(tca[TCA_KIND]),
protocol, prio, parent, q, block);
Expand All @@ -429,8 +498,7 @@ static int tc_ctl_tfilter(struct sk_buff *skb, struct nlmsghdr *n,

if (fh == 0) {
if (n->nlmsg_type == RTM_DELTFILTER && t->tcm_handle == 0) {
next = rtnl_dereference(tp->next);
RCU_INIT_POINTER(*back, next);
tcf_chain_tp_remove(chain, &chain_info, tp);
tfilter_notify(net, skb, n, tp, fh,
RTM_DELTFILTER, false);
tcf_proto_destroy(tp);
Expand Down Expand Up @@ -459,11 +527,10 @@ static int tc_ctl_tfilter(struct sk_buff *skb, struct nlmsghdr *n,
err = tp->ops->delete(tp, fh, &last);
if (err)
goto errout;
next = rtnl_dereference(tp->next);
tfilter_notify(net, skb, n, tp, t->tcm_handle,
RTM_DELTFILTER, false);
if (last) {
RCU_INIT_POINTER(*back, next);
tcf_chain_tp_remove(chain, &chain_info, tp);
tcf_proto_destroy(tp);
}
goto errout;
Expand All @@ -480,10 +547,8 @@ static int tc_ctl_tfilter(struct sk_buff *skb, struct nlmsghdr *n,
err = tp->ops->change(net, skb, tp, cl, t->tcm_handle, tca, &fh,
n->nlmsg_flags & NLM_F_CREATE ? TCA_ACT_NOREPLACE : TCA_ACT_REPLACE);
if (err == 0) {
if (tp_created) {
RCU_INIT_POINTER(tp->next, rtnl_dereference(*back));
rcu_assign_pointer(*back, tp);
}
if (tp_created)
tcf_chain_tp_insert(chain, &chain_info, tp);
tfilter_notify(net, skb, n, tp, fh, RTM_NEWTFILTER, false);
} else {
if (tp_created)
Expand Down Expand Up @@ -584,7 +649,8 @@ static int tc_dump_tfilter(struct sk_buff *skb, struct netlink_callback *cb)
struct net_device *dev;
struct Qdisc *q;
struct tcf_block *block;
struct tcf_proto *tp, __rcu **chain;
struct tcf_proto *tp;
struct tcf_chain *chain;
struct tcmsg *tcm = nlmsg_data(cb->nlh);
unsigned long cl = 0;
const struct Qdisc_class_ops *cops;
Expand Down Expand Up @@ -615,11 +681,11 @@ static int tc_dump_tfilter(struct sk_buff *skb, struct netlink_callback *cb)
block = cops->tcf_block(q, cl);
if (!block)
goto errout;
chain = block->p_filter_chain;
chain = block->chain;

s_t = cb->args[0];

for (tp = rtnl_dereference(*chain), t = 0;
for (tp = rtnl_dereference(chain->filter_chain), t = 0;
tp; tp = rtnl_dereference(tp->next), t++) {
if (t < s_t)
continue;
Expand Down

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