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Date: Sat, 14 Jan 2017 16:22:48 +0100
From: Jiri Pirko <jiri@...nulli.us>
To: Jamal Hadi Salim <jhs@...atatu.com>
Cc: davem@...emloft.net, netdev@...r.kernel.org, jiri@...lanox.com,
paulb@...lanox.com, john.fastabend@...il.com,
simon.horman@...ronome.com, mrv@...atatu.com, hadarh@...lanox.com,
ogerlitz@...lanox.com, roid@...lanox.com, xiyou.wangcong@...il.com,
daniel@...earbox.net, Jamal Hadi Salim <hadi@...atatu.com>
Subject: Re: [PATCH net-next 1/1] net sched actions: Add support for user
cookies
Sat, Jan 14, 2017 at 03:59:18PM CET, jhs@...atatu.com wrote:
>From: Jamal Hadi Salim <hadi@...atatu.com>
>
>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(using two 64bit values to represent the 128 bits):
>
>.. create an accept action with cookie 0xA:0xa0a0a0a0a0a0a0
>sudo $TC actions add action ok index 1 cookie 0xA 0xa0a0a0a0a0a0a0
2x 64bit values? Why can't this have variable length, according to what
user needs:
sudo $TC actions add action ok index 1 cookie a0
sudo $TC actions add action ok index 1 cookie a01122
sudo $TC actions add action ok index 1 cookie a01122334455
sudo $TC actions add action ok index 1 cookie a01122334455aabbccddeeff
>
>.. 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 2 bind 1 installed 1221 sec used 27 sec
> Action statistics:
> Sent 373248 bytes 5056 pkt (dropped 0, overlimits 0 requeues 0)
> backlog 0b 0p requeues 0
> cookie(0000000a:00000000:a0a0a0a0:00a0a0a0)
Input is 2x64 and dump is 4x32? That is confusing. With my suggested
example, this would be:
cookie a0
cookie a01122
cookie a01122334455
cookie a01122334455aabbccddeeff
>
>.. 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
>
>--- 127.0.0.1 ping statistics ---
>3 packets transmitted, 3 received, 0% packet loss, time 2109ms
>rtt min/avg/max/mdev = 0.020/0.028/0.038/0.008 ms 1
>
>... show some stats
>$ sudo $TC -s actions get action gact index 1
>
> action order 1: gact action pass
> random type none pass val 0
> index 1 ref 3 bind 1 installed 2182 sec used 1 sec
> Action statistics:
> Sent 700344 bytes 9486 pkt (dropped 0, overlimits 0 requeues 0)
> backlog 0b 0p requeues 0
>
>Signed-off-by: Jamal Hadi Salim <jhs@...atatu.com>
>---
> include/net/act_api.h | 7 +++++++
> include/uapi/linux/pkt_cls.h | 7 +++++++
> net/sched/act_api.c | 27 +++++++++++++++++++++++++--
> 3 files changed, 39 insertions(+), 2 deletions(-)
>
>diff --git a/include/net/act_api.h b/include/net/act_api.h
>index 1d71644..b948db9 100644
>--- a/include/net/act_api.h
>+++ b/include/net/act_api.h
>@@ -20,6 +20,12 @@ struct tcf_hashinfo {
>
> struct tc_action_ops;
>
>+union act_cookie {
>+ u16 ck16[8];
>+ u32 ck32[4];
>+ u64 ck64[2];
Since this should be never interpreted by kernel, I don't understand why
this union is needed. Why just don't pass a char array?
Also, whatever format this is, could we make is shared with cls cookie?
>+};
>+
> struct tc_action {
> const struct tc_action_ops *ops;
> __u32 type; /* for backward compat(TCA_OLD_COMPAT) */
>@@ -41,6 +47,7 @@ struct tc_action {
> struct rcu_head tcfa_rcu;
> struct gnet_stats_basic_cpu __percpu *cpu_bstats;
> struct gnet_stats_queue __percpu *cpu_qstats;
>+ union act_cookie *ck;
> };
> #define tcf_head common.tcfa_head
> #define tcf_index common.tcfa_index
>diff --git a/include/uapi/linux/pkt_cls.h b/include/uapi/linux/pkt_cls.h
>index 1e5e1dd..6379af3 100644
>--- a/include/uapi/linux/pkt_cls.h
>+++ b/include/uapi/linux/pkt_cls.h
>@@ -4,6 +4,12 @@
> #include <linux/types.h>
> #include <linux/pkt_sched.h>
>
>+union u_act_cookie {
>+ __u16 ck16[8];
>+ __u32 ck32[4];
>+ __u64 ck64[2];
>+};
Again, the same struct? I don't understand why twice.
>+
> /* Action attributes */
> enum {
> TCA_ACT_UNSPEC,
>@@ -12,6 +18,7 @@ enum {
> TCA_ACT_INDEX,
> TCA_ACT_STATS,
> TCA_ACT_PAD,
>+ TCA_ACT_COOKIE,
> __TCA_ACT_MAX
> };
>
>diff --git a/net/sched/act_api.c b/net/sched/act_api.c
>index f04715a..85e77181 100644
>--- a/net/sched/act_api.c
>+++ b/net/sched/act_api.c
>@@ -33,6 +33,7 @@ static void free_tcf(struct rcu_head *head)
>
> free_percpu(p->cpu_bstats);
> free_percpu(p->cpu_qstats);
>+ kfree(p->ck);
> kfree(p);
> }
>
>@@ -464,8 +465,8 @@ int tcf_action_destroy(struct list_head *actions, int bind)
> return a->ops->dump(skb, a, bind, ref);
> }
>
>-int
>-tcf_action_dump_1(struct sk_buff *skb, struct tc_action *a, int bind, int ref)
>+int tcf_action_dump_1(struct sk_buff *skb, struct tc_action *a, int bind,
>+ int ref)
> {
> int err = -EINVAL;
> unsigned char *b = skb_tail_pointer(skb);
>@@ -475,6 +476,12 @@ int tcf_action_destroy(struct list_head *actions, int bind)
> goto nla_put_failure;
> if (tcf_action_copy_stats(skb, a, 0))
> goto nla_put_failure;
>+ if (a->ck) {
>+ if (nla_put(skb, TCA_ACT_COOKIE, sizeof(union act_cookie),
>+ a->ck))
>+ goto nla_put_failure;
>+ }
>+
> nest = nla_nest_start(skb, TCA_OPTIONS);
> if (nest == NULL)
> goto nla_put_failure;
>@@ -575,6 +582,22 @@ struct tc_action *tcf_action_init_1(struct net *net, struct nlattr *nla,
> if (err < 0)
> goto err_mod;
>
>+ if (tb[TCA_ACT_COOKIE]) {
>+ if (nla_len(tb[TCA_ACT_COOKIE]) != sizeof(union act_cookie)) {
>+ err = -EINVAL;
>+ goto err_mod;
>+ }
>+
>+ a->ck = kzalloc(sizeof(union act_cookie), GFP_KERNEL);
>+ if (unlikely(!a->ck)) {
>+ err = -ENOMEM;
>+ goto err_mod;
>+ }
>+
>+ memcpy((void *)a->ck, nla_data(tb[TCA_ACT_COOKIE]),
>+ sizeof(union act_cookie));
>+ }
>+
> /* 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).
>--
>1.9.1
>
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