2 * m_simple.c simple action
4 * This program is free software; you can distribute it and/or
5 * modify it under the terms of the GNU General Public License
6 * as published by the Free Software Foundation; either version
7 * 2 of the License, or (at your option) any later version.
9 * Authors: J Hadi Salim <jhs@mojatatu.com>
11 * Pedagogical example. Adds a string that will be printed every time
12 * the simple instance is hit.
13 * Use this as a skeleton action and keep modifying it to meet your needs.
14 * Look at linux/tc_act/tc_defact.h for the different components ids and
15 * definitions used in this actions
17 * example use, yell "Incoming ICMP!" every time you see an incoming ICMP on
19 * 1) Add an ingress qdisc point to eth0
20 * 2) Start a chain on ingress of eth0 that first matches ICMP then invokes
21 * the simple action to shout.
22 * 3) display stats and show that no packet has been seen by the action
23 * 4) Send one ping packet to google (expect to receive a response back)
24 * 5) grep the logs to see the logged message
25 * 6) display stats again and observe increment by 1
27 hadi@noma1:$ tc qdisc add dev eth0 ingress
28 hadi@noma1:$tc filter add dev eth0 parent ffff: protocol ip prio 5 \
29 u32 match ip protocol 1 0xff flowid 1:1 action simple "Incoming ICMP"
31 hadi@noma1:$ sudo tc -s filter ls dev eth0 parent ffff:
32 filter protocol ip pref 5 u32
33 filter protocol ip pref 5 u32 fh 800: ht divisor 1
34 filter protocol ip pref 5 u32 fh 800::800 order 2048 key ht 800 bkt 0 flowid 1:1
35 match 00010000/00ff0000 at 8
36 action order 1: Simple <Incoming ICMP>
37 index 4 ref 1 bind 1 installed 29 sec used 29 sec
39 Sent 0 bytes 0 pkt (dropped 0, overlimits 0 requeues 0)
40 backlog 0b 0p requeues 0
43 hadi@noma1$ ping -c 1 www.google.ca
44 PING www.google.ca (74.125.225.120) 56(84) bytes of data.
45 64 bytes from ord08s08-in-f24.1e100.net (74.125.225.120): icmp_req=1 ttl=53 time=31.3 ms
47 --- www.google.ca ping statistics ---
48 1 packets transmitted, 1 received, 0% packet loss, time 0ms
49 rtt min/avg/max/mdev = 31.316/31.316/31.316/0.000 ms
51 hadi@noma1$ dmesg | grep simple
52 [135354.473951] simple: Incoming ICMP_1
54 hadi@noma1$ sudo tc/tc -s filter ls dev eth0 parent ffff:
55 filter protocol ip pref 5 u32
56 filter protocol ip pref 5 u32 fh 800: ht divisor 1
57 filter protocol ip pref 5 u32 fh 800::800 order 2048 key ht 800 bkt 0 flowid 1:1
58 match 00010000/00ff0000 at 8
59 action order 1: Simple <Incoming ICMP>
60 index 4 ref 1 bind 1 installed 206 sec used 67 sec
62 Sent 84 bytes 1 pkt (dropped 0, overlimits 0 requeues 0)
63 backlog 0b 0p requeues 0
71 #include <sys/socket.h>
72 #include <netinet/in.h>
73 #include <arpa/inet.h>
77 #include <linux/tc_act/tc_defact.h>
80 #define SIMP_MAX_DATA 32
82 static void explain(void)
84 fprintf(stderr
, "Usage:... simple [sdata STRING] [CONTROL] [index INDEX]\n");
85 fprintf(stderr
, "\tSTRING being an arbitrary string\n"
86 "\tCONTROL := reclassify|pipe|drop|continue|ok\n"
87 "\tINDEX := optional index value used\n");
90 static void usage(void)
97 parse_simple(struct action_util
*a
, int *argc_p
, char ***argv_p
, int tca_id
,
100 struct tc_defact sel
= {};
102 char **argv
= *argv_p
;
105 char *simpdata
= NULL
;
108 if (matches(*argv
, "simple") == 0) {
110 } else if (matches(*argv
, "sdata") == 0) {
116 } else if (matches(*argv
, "help") == 0) {
124 if (matches(*argv
, "index") == 0) {
126 if (get_u32(&sel
.index
, *argv
, 10)) {
127 fprintf(stderr
, "simple: Illegal \"index\" (%s)\n",
142 if (simpdata
&& (strlen(simpdata
) > (SIMP_MAX_DATA
- 1))) {
143 fprintf(stderr
, "simple: Illegal string len %zu <%s>\n",
144 strlen(simpdata
), simpdata
);
148 sel
.action
= TC_ACT_PIPE
;
150 tail
= NLMSG_TAIL(n
);
151 addattr_l(n
, MAX_MSG
, tca_id
, NULL
, 0);
152 addattr_l(n
, MAX_MSG
, TCA_DEF_PARMS
, &sel
, sizeof(sel
));
154 addattr_l(n
, MAX_MSG
, TCA_DEF_DATA
, simpdata
, SIMP_MAX_DATA
);
155 tail
->rta_len
= (char *)NLMSG_TAIL(n
) - (char *)tail
;
162 static int print_simple(struct action_util
*au
, FILE *f
, struct rtattr
*arg
)
164 struct tc_defact
*sel
;
165 struct rtattr
*tb
[TCA_DEF_MAX
+ 1];
171 parse_rtattr_nested(tb
, TCA_DEF_MAX
, arg
);
173 if (tb
[TCA_DEF_PARMS
] == NULL
) {
174 fprintf(f
, "[NULL simple parameters]");
177 sel
= RTA_DATA(tb
[TCA_DEF_PARMS
]);
179 if (tb
[TCA_DEF_DATA
] == NULL
) {
180 fprintf(f
, "[missing simple string]");
184 simpdata
= RTA_DATA(tb
[TCA_DEF_DATA
]);
186 fprintf(f
, "Simple <%s>\n", simpdata
);
187 fprintf(f
, "\t index %u ref %d bind %d", sel
->index
,
188 sel
->refcnt
, sel
->bindcnt
);
191 if (tb
[TCA_DEF_TM
]) {
192 struct tcf_t
*tm
= RTA_DATA(tb
[TCA_DEF_TM
]);
202 struct action_util simple_action_util
= {
204 .parse_aopt
= parse_simple
,
205 .print_aopt
= print_simple
,