From 1045ba77a5962a22bce7777678ef46714107ea63 Mon Sep 17 00:00:00 2001 From: Jamal Hadi Salim Date: Tue, 24 Jan 2017 07:02:41 -0500 Subject: [PATCH] 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 --- include/net/act_api.h | 1 + include/net/pkt_cls.h | 8 +++++++ include/uapi/linux/pkt_cls.h | 3 +++ net/sched/act_api.c | 45 ++++++++++++++++++++++++++++++++++++ 4 files changed, 57 insertions(+) diff --git a/include/net/act_api.h b/include/net/act_api.h index 1d716449209e..cfa2ae33da9a 100644 --- a/include/net/act_api.h +++ b/include/net/act_api.h @@ -41,6 +41,7 @@ struct tc_action { struct rcu_head tcfa_rcu; struct gnet_stats_basic_cpu __percpu *cpu_bstats; struct gnet_stats_queue __percpu *cpu_qstats; + struct tc_cookie *act_cookie; }; #define tcf_head common.tcfa_head #define tcf_index common.tcfa_index diff --git a/include/net/pkt_cls.h b/include/net/pkt_cls.h index f0a051480c6c..b43077e47d35 100644 --- a/include/net/pkt_cls.h +++ b/include/net/pkt_cls.h @@ -515,4 +515,12 @@ struct tc_cls_bpf_offload { u32 gen_flags; }; + +/* This structure holds cookie structure that is passed from user + * to the kernel for actions and classifiers + */ +struct tc_cookie { + u8 *data; + u32 len; +}; #endif diff --git a/include/uapi/linux/pkt_cls.h b/include/uapi/linux/pkt_cls.h index fd373ebd5a44..345551e71410 100644 --- a/include/uapi/linux/pkt_cls.h +++ b/include/uapi/linux/pkt_cls.h @@ -4,6 +4,8 @@ #include #include +#define TC_COOKIE_MAX_SIZE 16 + /* Action attributes */ enum { TCA_ACT_UNSPEC, @@ -12,6 +14,7 @@ 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 cd08df91351d..3c5e29ba6594 100644 --- a/net/sched/act_api.c +++ b/net/sched/act_api.c @@ -24,6 +24,7 @@ #include #include #include +#include #include #include @@ -33,6 +34,12 @@ static void free_tcf(struct rcu_head *head) 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 @@ tcf_action_dump_1(struct sk_buff *skb, struct tc_action *a, int bind, int ref) 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 @@ errout: 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 @@ struct tc_action *tcf_action_init_1(struct net *net, struct nlattr *nla, 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).