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/* SPDX-License-Identifier: GPL-2.0-or-later */
/*
* m_simple.c simple action
*
* Authors: J Hadi Salim <jhs@mojatatu.com>
*
* Pedagogical example. Adds a string that will be printed every time
* the simple instance is hit.
* Use this as a skeleton action and keep modifying it to meet your needs.
* Look at linux/tc_act/tc_defact.h for the different components ids and
* definitions used in this actions
*
* example use, yell "Incoming ICMP!" every time you see an incoming ICMP on
* eth0. Steps are:
* 1) Add an ingress qdisc point to eth0
* 2) Start a chain on ingress of eth0 that first matches ICMP then invokes
* the simple action to shout.
* 3) display stats and show that no packet has been seen by the action
* 4) Send one ping packet to google (expect to receive a response back)
* 5) grep the logs to see the logged message
* 6) display stats again and observe increment by 1
*
hadi@noma1:$ tc qdisc add dev eth0 ingress
hadi@noma1:$tc filter add dev eth0 parent ffff: protocol ip prio 5 \
u32 match ip protocol 1 0xff flowid 1:1 action simple "Incoming ICMP"
hadi@noma1:$ sudo tc -s filter ls dev eth0 parent ffff:
filter protocol ip pref 5 u32
filter protocol ip pref 5 u32 fh 800: ht divisor 1
filter protocol ip pref 5 u32 fh 800::800 order 2048 key ht 800 bkt 0 flowid 1:1
match 00010000/00ff0000 at 8
action order 1: Simple <Incoming ICMP>
index 4 ref 1 bind 1 installed 29 sec used 29 sec
Action statistics:
Sent 0 bytes 0 pkt (dropped 0, overlimits 0 requeues 0)
backlog 0b 0p requeues 0
hadi@noma1$ ping -c 1 www.google.ca
PING www.google.ca (74.125.225.120) 56(84) bytes of data.
64 bytes from ord08s08-in-f24.1e100.net (74.125.225.120): icmp_req=1 ttl=53 time=31.3 ms
--- www.google.ca ping statistics ---
1 packets transmitted, 1 received, 0% packet loss, time 0ms
rtt min/avg/max/mdev = 31.316/31.316/31.316/0.000 ms
hadi@noma1$ dmesg | grep simple
[135354.473951] simple: Incoming ICMP_1
hadi@noma1$ sudo tc/tc -s filter ls dev eth0 parent ffff:
filter protocol ip pref 5 u32
filter protocol ip pref 5 u32 fh 800: ht divisor 1
filter protocol ip pref 5 u32 fh 800::800 order 2048 key ht 800 bkt 0 flowid 1:1
match 00010000/00ff0000 at 8
action order 1: Simple <Incoming ICMP>
index 4 ref 1 bind 1 installed 206 sec used 67 sec
Action statistics:
Sent 84 bytes 1 pkt (dropped 0, overlimits 0 requeues 0)
backlog 0b 0p requeues 0
*/
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <fcntl.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <string.h>
#include "utils.h"
#include "tc_util.h"
#include <linux/tc_act/tc_defact.h>
#ifndef SIMP_MAX_DATA
#define SIMP_MAX_DATA 32
#endif
static void explain(void)
{
fprintf(stderr,
"Usage:... simple [sdata STRING] [index INDEX] [CONTROL]\n"
"\tSTRING being an arbitrary string\n"
"\tINDEX := optional index value used\n"
"\tCONTROL := reclassify|pipe|drop|continue|ok\n");
}
static void usage(void)
{
explain();
exit(-1);
}
static int
parse_simple(const struct action_util *a, int *argc_p, char ***argv_p, int tca_id,
struct nlmsghdr *n)
{
struct tc_defact sel = {};
int argc = *argc_p;
char **argv = *argv_p;
int ok = 0;
struct rtattr *tail;
char *simpdata = NULL;
while (argc > 0) {
if (matches(*argv, "simple") == 0) {
NEXT_ARG();
} else if (matches(*argv, "sdata") == 0) {
NEXT_ARG();
ok += 1;
simpdata = *argv;
argc--;
argv++;
} else if (matches(*argv, "help") == 0) {
usage();
} else {
break;
}
}
parse_action_control_dflt(&argc, &argv, &sel.action, false,
TC_ACT_PIPE);
if (argc) {
if (matches(*argv, "index") == 0) {
NEXT_ARG();
if (get_u32(&sel.index, *argv, 10)) {
fprintf(stderr, "simple: Illegal \"index\" (%s)\n",
*argv);
return -1;
}
ok += 1;
argc--;
argv++;
}
}
if (!ok) {
explain();
return -1;
}
if (simpdata && (strlen(simpdata) > (SIMP_MAX_DATA - 1))) {
fprintf(stderr, "simple: Illegal string len %zu <%s>\n",
strlen(simpdata), simpdata);
return -1;
}
tail = addattr_nest(n, MAX_MSG, tca_id);
addattr_l(n, MAX_MSG, TCA_DEF_PARMS, &sel, sizeof(sel));
if (simpdata)
addattr_l(n, MAX_MSG, TCA_DEF_DATA, simpdata, SIMP_MAX_DATA);
addattr_nest_end(n, tail);
*argc_p = argc;
*argv_p = argv;
return 0;
}
static int print_simple(const struct action_util *au, FILE *f, struct rtattr *arg)
{
struct tc_defact *sel;
struct rtattr *tb[TCA_DEF_MAX + 1];
char *simpdata;
if (arg == NULL)
return 0;
parse_rtattr_nested(tb, TCA_DEF_MAX, arg);
if (tb[TCA_DEF_PARMS] == NULL) {
fprintf(stderr, "Missing simple parameters\n");
return -1;
}
sel = RTA_DATA(tb[TCA_DEF_PARMS]);
if (tb[TCA_DEF_DATA] == NULL) {
fprintf(stderr, "Missing simple string\n");
return -1;
}
simpdata = RTA_DATA(tb[TCA_DEF_DATA]);
print_string(PRINT_ANY, "simple", "Simple <%s>", simpdata);
print_nl();
print_uint(PRINT_ANY, "index", "\t index %u ", sel->index);
print_int(PRINT_ANY, "ref", "ref %d ", sel->refcnt);
print_int(PRINT_ANY, "bind","bind %d", sel->bindcnt);
if (show_stats) {
if (tb[TCA_DEF_TM]) {
struct tcf_t *tm = RTA_DATA(tb[TCA_DEF_TM]);
print_tm(tm);
}
}
print_nl();
return 0;
}
struct action_util simple_action_util = {
.id = "simple",
.parse_aopt = parse_simple,
.print_aopt = print_simple,
};
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