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 (at) 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 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 89 static void usage(void) 90 { 91 explain(); 92 exit(-1); 93 } 94 95 static int 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 } 158 159 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
