diff mbox

[iproute2,1/1] actions: Add support for user cookies

Message ID 1492864583-20892-1-git-send-email-jhs@emojatatu.com
State Accepted, archived
Delegated to: stephen hemminger
Headers show

Commit Message

Jamal Hadi Salim April 22, 2017, 12:36 p.m. UTC 
From: Jamal Hadi Salim <jhs@mojatatu.com>

Make use of 128b 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: Jamal Hadi Salim <jhs@mojatatu.com>
---
 tc/m_action.c | 49 +++++++++++++++++++++++++++++++++++++++++++------
 1 file changed, 43 insertions(+), 6 deletions(-)

Comments

Stephen Hemminger April 23, 2017, 4:11 p.m. UTC | #1 
On Sat, 22 Apr 2017 08:36:23 -0400
Jamal Hadi Salim <jhs@mojatatu.com> wrote:

> From: Jamal Hadi Salim <jhs@mojatatu.com>
> 
> Make use of 128b 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: Jamal Hadi Salim <jhs@mojatatu.com>

Applied. Please update man page as well.
Jamal Hadi Salim April 23, 2017, 5:18 p.m. UTC | #2 
On 17-04-23 12:11 PM, Stephen Hemminger wrote:
> On Sat, 22 Apr 2017 08:36:23 -0400

>
> Applied. Please update man page as well.
>
>

Will do.

cheers,
jamal
Jiri Pirko Nov. 23, 2017, 4:36 p.m. UTC | #3 
Sat, Apr 22, 2017 at 02:36:23PM CEST, jhs@mojatatu.com wrote:

[...]

>@@ -274,8 +302,17 @@ tc_print_one_action(FILE *f, struct rtattr *arg)
> 		return err;
> 
> 	if (show_stats && tb[TCA_ACT_STATS]) {
>+
> 		fprintf(f, "\tAction statistics:\n");
> 		print_tcstats2_attr(f, tb[TCA_ACT_STATS], "\t", NULL);
>+		if (tb[TCA_ACT_COOKIE]) {
>+			int strsz = RTA_PAYLOAD(tb[TCA_ACT_COOKIE]);
>+			char b1[strsz+1];
>+
>+			fprintf(f, "\n\tcookie len %d %s ", strsz,
>+				hexstring_n2a(RTA_DATA(tb[TCA_ACT_COOKIE]),
>+					      strsz, b1, sizeof(b1)));
>+		}


Jamal, is there any particular reason that you print cookie only in case
you show stats? What is the relation between cookie and stats?



> 		fprintf(f, "\n");
> 	}
> 
>-- 
>1.9.1
>
Jamal Hadi Salim Nov. 23, 2017, 5:32 p.m. UTC | #4 
On 17-11-23 11:36 AM, Jiri Pirko wrote:
> Sat, Apr 22, 2017 at 02:36:23PM CEST, jhs@mojatatu.com wrote:
> 
> [...]
> 

[..]
> 
> Jamal, is there any particular reason that you print cookie only in case
> you show stats? What is the relation between cookie and stats?

-s has been thus far used to imply "verbose" on. Other than that
no good reason.

cheers,
jamal
Jiri Pirko Nov. 23, 2017, 5:55 p.m. UTC | #5 
Thu, Nov 23, 2017 at 06:32:38PM CET, jhs@mojatatu.com wrote:
>On 17-11-23 11:36 AM, Jiri Pirko wrote:
>> Sat, Apr 22, 2017 at 02:36:23PM CEST, jhs@mojatatu.com wrote:
>> 
>> [...]
>> 
>
>[..]
>> 
>> Jamal, is there any particular reason that you print cookie only in case
>> you show stats? What is the relation between cookie and stats?
>
>-s has been thus far used to imply "verbose" on. Other than that

:O Afaik, "-d" is used for that in iproute2 suite.

>no good reason.

Ok, I will move it out.

>
>cheers,
>jamal
>
Stephen Hemminger Nov. 23, 2017, 9:09 p.m. UTC | #6 
On Sat, 22 Apr 2017 08:36:23 -0400
Jamal Hadi Salim <jhs@mojatatu.com> wrote:

> +
> +			if (*argv && strcmp(*argv, "cookie") == 0) {
> +				size_t slen;
> +
> +				NEXT_ARG();
> +				slen = strlen(*argv);
> +				if (slen > TC_COOKIE_MAX_SIZE * 2) {
> +					char cookie_err_m[128];
> +
> +					snprintf(cookie_err_m, 128,
> +						 "%zd Max allowed size %d",
> +						 slen, TC_COOKIE_MAX_SIZE*2);
> +					invarg(cookie_err_m, *argv);

Don't bother going to effort of building a string for invarg(). Instead either
just print invalid cookie or use fprintf.

Also, what if kernel limits change?
Stephen Hemminger Nov. 23, 2017, 9:12 p.m. UTC | #7 
On Sat, 22 Apr 2017 08:36:23 -0400
Jamal Hadi Salim <jhs@mojatatu.com> wrote:

> +
>  		fprintf(f, "\tAction statistics:\n");
>  		print_tcstats2_attr(f, tb[TCA_ACT_STATS], "\t", NULL);
> +		if (tb[TCA_ACT_COOKIE]) {
> +			int strsz = RTA_PAYLOAD(tb[TCA_ACT_COOKIE]);
> +			char b1[strsz+1];
> +
> +			fprintf(f, "\n\tcookie len %d %s ", strsz,
> +				hexstring_n2a(RTA_DATA(tb[TCA_ACT_COOKIE]),
> +					      strsz, b1, sizeof(b1)))

I don't think you need to print len here. Already know that by the output of 
hexstring. Since payload length is in bytes and hex takes two characters per byte
then the buffer needs to be bigger (like TCPCOOKIE_MAX_SIZE * 2 + 1)
diff mbox

Patch

diff --git a/tc/m_action.c b/tc/m_action.c
index 05ef07e..6ebe85e 100644
--- a/tc/m_action.c
+++ b/tc/m_action.c
@@ -150,18 +150,19 @@  new_cmd(char **argv)
 
 }
 
-int
-parse_action(int *argc_p, char ***argv_p, int tca_id, struct nlmsghdr *n)
+int parse_action(int *argc_p, char ***argv_p, int tca_id, struct nlmsghdr *n)
 {
 	int argc = *argc_p;
 	char **argv = *argv_p;
 	struct rtattr *tail, *tail2;
 	char k[16];
+	int act_ck_len = 0;
 	int ok = 0;
 	int eap = 0; /* expect action parameters */
 
 	int ret = 0;
 	int prio = 0;
+	unsigned char act_ck[TC_COOKIE_MAX_SIZE];
 
 	if (argc <= 0)
 		return -1;
@@ -215,16 +216,44 @@  done0:
 			addattr_l(n, MAX_MSG, ++prio, NULL, 0);
 			addattr_l(n, MAX_MSG, TCA_ACT_KIND, k, strlen(k) + 1);
 
-			ret = a->parse_aopt(a, &argc, &argv, TCA_ACT_OPTIONS, n);
+			ret = a->parse_aopt(a, &argc, &argv, TCA_ACT_OPTIONS,
+					    n);
 
 			if (ret < 0) {
 				fprintf(stderr, "bad action parsing\n");
 				goto bad_val;
 			}
+
+			if (*argv && strcmp(*argv, "cookie") == 0) {
+				size_t slen;
+
+				NEXT_ARG();
+				slen = strlen(*argv);
+				if (slen > TC_COOKIE_MAX_SIZE * 2) {
+					char cookie_err_m[128];
+
+					snprintf(cookie_err_m, 128,
+						 "%zd Max allowed size %d",
+						 slen, TC_COOKIE_MAX_SIZE*2);
+					invarg(cookie_err_m, *argv);
+				}
+
+				if (hex2mem(*argv, act_ck, slen / 2) < 0)
+					invarg("cookie must be a hex string\n",
+					       *argv);
+
+				act_ck_len = slen;
+				argc--;
+				argv++;
+			}
+
+			if (act_ck_len)
+				addattr_l(n, MAX_MSG, TCA_ACT_COOKIE,
+					  &act_ck, act_ck_len);
+
 			tail->rta_len = (void *) NLMSG_TAIL(n) - (void *) tail;
 			ok++;
 		}
-
 	}
 
 	if (eap > 0) {
@@ -245,8 +274,7 @@  bad_val:
 	return -1;
 }
 
-static int
-tc_print_one_action(FILE *f, struct rtattr *arg)
+static int tc_print_one_action(FILE *f, struct rtattr *arg)
 {
 
 	struct rtattr *tb[TCA_ACT_MAX + 1];
@@ -274,8 +302,17 @@  tc_print_one_action(FILE *f, struct rtattr *arg)
 		return err;
 
 	if (show_stats && tb[TCA_ACT_STATS]) {
+
 		fprintf(f, "\tAction statistics:\n");
 		print_tcstats2_attr(f, tb[TCA_ACT_STATS], "\t", NULL);
+		if (tb[TCA_ACT_COOKIE]) {
+			int strsz = RTA_PAYLOAD(tb[TCA_ACT_COOKIE]);
+			char b1[strsz+1];
+
+			fprintf(f, "\n\tcookie len %d %s ", strsz,
+				hexstring_n2a(RTA_DATA(tb[TCA_ACT_COOKIE]),
+					      strsz, b1, sizeof(b1)));
+		}
 		fprintf(f, "\n");
 	}