1 /*
2 * m_simple.c simple action
3 *
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.
8 *
9 * Authors: J Hadi Salim <jhs@mojatatu.com>
10 *
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
16 *
17 * example use, yell "Incoming ICMP!" every time you see an incoming ICMP on
18 * eth0. Steps are:
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
26 *
27 hadi@noma1:$ tc qdisc add dev eth0 ingress
28 hadi@noma1:$tc filter add dev eth0 parent ffff: protocol ip prio 5 \
29 u32 match ip protocol 1 0xff flowid 1:1 action simple "Incoming ICMP"
30
31 hadi@noma1:$ 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
38 Action statistics:
39 Sent 0 bytes 0 pkt (dropped 0, overlimits 0 requeues 0)
40 backlog 0b 0p requeues 0
41
42
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
46
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
50
51 hadi@noma1$ dmesg | grep simple
52 [135354.473951] simple: Incoming ICMP_1
53
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
61 Action statistics:
62 Sent 84 bytes 1 pkt (dropped 0, overlimits 0 requeues 0)
63 backlog 0b 0p requeues 0
64 */
65
66 #include <stdio.h>
67 #include <stdlib.h>
68 #include <unistd.h>
69 #include <syslog.h>
70 #include <fcntl.h>
71 #include <sys/socket.h>
72 #include <netinet/in.h>
73 #include <arpa/inet.h>
74 #include <string.h>
75 #include "utils.h"
76 #include "tc_util.h"
77 #include <linux/tc_act/tc_defact.h>
78
79 #ifndef SIMP_MAX_DATA
80 #define SIMP_MAX_DATA 32
81 #endif
explain(void)82 static void explain(void)
83 {
84 fprintf(stderr, "Usage: ... simple STRING\n"
85 "STRING being an arbitrary string\n"
86 "example: \"simple blah\"\n");
87 }
88
usage(void)89 static void usage(void)
90 {
91 explain();
92 exit(-1);
93 }
94
95 static int
parse_simple(struct action_util * a,int * argc_p,char *** argv_p,int tca_id,struct nlmsghdr * n)96 parse_simple(struct action_util *a, int *argc_p, char ***argv_p, int tca_id,
97 struct nlmsghdr *n)
98 {
99 struct tc_defact sel = {};
100 int argc = *argc_p;
101 char **argv = *argv_p;
102 int ok = 0;
103 struct rtattr *tail;
104 char *simpdata = NULL;
105
106
107 while (argc > 0) {
108 if (matches(*argv, "simple") == 0) {
109 NEXT_ARG();
110 simpdata = *argv;
111 ok = 1;
112 argc--;
113 argv++;
114 break;
115 } else if (matches(*argv, "help") == 0) {
116 usage();
117 } else {
118 break;
119 }
120
121 }
122
123 if (!ok) {
124 explain();
125 return -1;
126 }
127
128 if (argc) {
129 if (matches(*argv, "index") == 0) {
130 NEXT_ARG();
131 if (get_u32(&sel.index, *argv, 10)) {
132 fprintf(stderr, "simple: Illegal \"index\"\n");
133 return -1;
134 }
135 argc--;
136 argv++;
137 }
138 }
139
140 if (strlen(simpdata) > (SIMP_MAX_DATA - 1)) {
141 fprintf(stderr, "simple: Illegal string len %zu <%s> \n",
142 strlen(simpdata), simpdata);
143 return -1;
144 }
145
146 sel.action = TC_ACT_PIPE;
147
148 tail = NLMSG_TAIL(n);
149 addattr_l(n, MAX_MSG, tca_id, NULL, 0);
150 addattr_l(n, MAX_MSG, TCA_DEF_PARMS, &sel, sizeof(sel));
151 addattr_l(n, MAX_MSG, TCA_DEF_DATA, simpdata, SIMP_MAX_DATA);
152 tail->rta_len = (char *)NLMSG_TAIL(n) - (char *)tail;
153
154 *argc_p = argc;
155 *argv_p = argv;
156 return 0;
157 }
158
print_simple(struct action_util * au,FILE * f,struct rtattr * arg)159 static int print_simple(struct action_util *au, FILE * f, struct rtattr *arg)
160 {
161 struct tc_defact *sel;
162 struct rtattr *tb[TCA_DEF_MAX + 1];
163 char *simpdata;
164
165 if (arg == NULL)
166 return -1;
167
168 parse_rtattr_nested(tb, TCA_DEF_MAX, arg);
169
170 if (tb[TCA_DEF_PARMS] == NULL) {
171 fprintf(f, "[NULL simple parameters]");
172 return -1;
173 }
174 sel = RTA_DATA(tb[TCA_DEF_PARMS]);
175
176 if (tb[TCA_DEF_DATA] == NULL) {
177 fprintf(f, "[missing simple string]");
178 return -1;
179 }
180
181 simpdata = RTA_DATA(tb[TCA_DEF_DATA]);
182
183 fprintf(f, "Simple <%s>\n", simpdata);
184 fprintf(f, "\t index %d ref %d bind %d", sel->index,
185 sel->refcnt, sel->bindcnt);
186
187 if (show_stats) {
188 if (tb[TCA_DEF_TM]) {
189 struct tcf_t *tm = RTA_DATA(tb[TCA_DEF_TM]);
190 print_tm(f, tm);
191 }
192 }
193 fprintf(f, "\n");
194
195 return 0;
196 }
197
198 struct action_util simple_action_util = {
199 .id = "simple",
200 .parse_aopt = parse_simple,
201 .print_aopt = print_simple,
202 };
203