net sched actions: Add support for user cookies
Introduce optional 128-bit action cookie.
Like all other cookie schemes in the networking world (eg in protocols
like http or existing kernel fib protocol field, etc) the idea is to save
user state that when retrieved serves as a correlator. The kernel
_should not_ intepret it. The user can store whatever they wish in the
128 bits.
Sample exercise(showing variable length use of cookie)
.. create an accept action with cookie a1b2c3d4
sudo $TC actions add action ok index 1 cookie a1b2c3d4
.. dump all gact actions..
sudo $TC -s actions ls action gact
action order 0: gact action pass
random type none pass val 0
index 1 ref 1 bind 0 installed 5 sec used 5 sec
Action statistics:
Sent 0 bytes 0 pkt (dropped 0, overlimits 0 requeues 0)
backlog 0b 0p requeues 0
cookie a1b2c3d4
.. bind the accept action to a filter..
sudo $TC filter add dev lo parent ffff: protocol ip prio 1 \
u32 match ip dst 127.0.0.1/32 flowid 1:1 action gact index 1
... send some traffic..
$ ping 127.0.0.1 -c 3
PING 127.0.0.1 (127.0.0.1) 56(84) bytes of data.
64 bytes from 127.0.0.1: icmp_seq=1 ttl=64 time=0.020 ms
64 bytes from 127.0.0.1: icmp_seq=2 ttl=64 time=0.027 ms
64 bytes from 127.0.0.1: icmp_seq=3 ttl=64 time=0.038 ms
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/sched/act_api.c b/net/sched/act_api.c
index cd08df9..3c5e29b 100644
--- a/net/sched/act_api.c
+++ b/net/sched/act_api.c
@@ -24,6 +24,7 @@
#include <net/net_namespace.h>
#include <net/sock.h>
#include <net/sch_generic.h>
+#include <net/pkt_cls.h>
#include <net/act_api.h>
#include <net/netlink.h>
@@ -33,6 +34,12 @@
free_percpu(p->cpu_bstats);
free_percpu(p->cpu_qstats);
+
+ if (p->act_cookie) {
+ kfree(p->act_cookie->data);
+ kfree(p->act_cookie);
+ }
+
kfree(p);
}
@@ -475,6 +482,12 @@
goto nla_put_failure;
if (tcf_action_copy_stats(skb, a, 0))
goto nla_put_failure;
+ if (a->act_cookie) {
+ if (nla_put(skb, TCA_ACT_COOKIE, a->act_cookie->len,
+ a->act_cookie->data))
+ goto nla_put_failure;
+ }
+
nest = nla_nest_start(skb, TCA_OPTIONS);
if (nest == NULL)
goto nla_put_failure;
@@ -516,6 +529,22 @@
return err;
}
+int nla_memdup_cookie(struct tc_action *a, struct nlattr **tb)
+{
+ a->act_cookie = kzalloc(sizeof(*a->act_cookie), GFP_KERNEL);
+ if (!a->act_cookie)
+ return -ENOMEM;
+
+ a->act_cookie->data = nla_memdup(tb[TCA_ACT_COOKIE], GFP_KERNEL);
+ if (!a->act_cookie->data) {
+ kfree(a->act_cookie);
+ return -ENOMEM;
+ }
+ a->act_cookie->len = nla_len(tb[TCA_ACT_COOKIE]);
+
+ return 0;
+}
+
struct tc_action *tcf_action_init_1(struct net *net, struct nlattr *nla,
struct nlattr *est, char *name, int ovr,
int bind)
@@ -575,6 +604,22 @@
if (err < 0)
goto err_mod;
+ if (tb[TCA_ACT_COOKIE]) {
+ int cklen = nla_len(tb[TCA_ACT_COOKIE]);
+
+ if (cklen > TC_COOKIE_MAX_SIZE) {
+ err = -EINVAL;
+ tcf_hash_release(a, bind);
+ goto err_mod;
+ }
+
+ err = nla_memdup_cookie(a, tb);
+ if (err < 0) {
+ tcf_hash_release(a, bind);
+ goto err_mod;
+ }
+ }
+
/* module count goes up only when brand new policy is created
* if it exists and is only bound to in a_o->init() then
* ACT_P_CREATED is not returned (a zero is).