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 [sdata STRING] [index INDEX] [CONTROL]\n"); 85 fprintf(stderr, "\tSTRING being an arbitrary string\n" 86 "\tINDEX := optional index value used\n" 87 "\tCONTROL := reclassify|pipe|drop|continue|ok\n"); 88 } 89 90 static void usage(void) 91 { 92 explain(); 93 exit(-1); 94 } 95 96 static int 97 parse_simple(struct action_util *a, int *argc_p, char ***argv_p, int tca_id, 98 struct nlmsghdr *n) 99 { 100 struct tc_defact sel = {}; 101 int argc = *argc_p; 102 char **argv = *argv_p; 103 int ok = 0; 104 struct rtattr *tail; 105 char *simpdata = NULL; 106 107 while (argc > 0) { 108 if (matches(*argv, "simple") == 0) { 109 NEXT_ARG(); 110 } else if (matches(*argv, "sdata") == 0) { 111 NEXT_ARG(); 112 ok += 1; 113 simpdata = *argv; 114 argc--; 115 argv++; 116 } else if (matches(*argv, "help") == 0) { 117 usage(); 118 } else { 119 break; 120 } 121 } 122 123 if (argc) { 124 if (matches(*argv, "index") == 0) { 125 NEXT_ARG(); 126 if (get_u32(&sel.index, *argv, 10)) { 127 fprintf(stderr, "simple: Illegal \"index\" (%s)\n", 128 *argv); 129 return -1; 130 } 131 ok += 1; 132 argc--; 133 argv++; 134 } 135 } 136 137 if (!ok) { 138 explain(); 139 return -1; 140 } 141 142 if (simpdata && (strlen(simpdata) > (SIMP_MAX_DATA - 1))) { 143 fprintf(stderr, "simple: Illegal string len %zu <%s>\n", 144 strlen(simpdata), simpdata); 145 return -1; 146 } 147 148 sel.action = TC_ACT_PIPE; 149 150 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)); 153 if (simpdata) 154 addattr_l(n, MAX_MSG, TCA_DEF_DATA, simpdata, SIMP_MAX_DATA); 155 tail->rta_len = (char *)NLMSG_TAIL(n) - (char *)tail; 156 157 *argc_p = argc; 158 *argv_p = argv; 159 return 0; 160 } 161 162 static int print_simple(struct action_util *au, FILE *f, struct rtattr *arg) 163 { 164 struct tc_defact *sel; 165 struct rtattr *tb[TCA_DEF_MAX + 1]; 166 char *simpdata; 167 168 if (arg == NULL) 169 return -1; 170 171 parse_rtattr_nested(tb, TCA_DEF_MAX, arg); 172 173 if (tb[TCA_DEF_PARMS] == NULL) { 174 fprintf(f, "[NULL simple parameters]"); 175 return -1; 176 } 177 sel = RTA_DATA(tb[TCA_DEF_PARMS]); 178 179 if (tb[TCA_DEF_DATA] == NULL) { 180 fprintf(f, "[missing simple string]"); 181 return -1; 182 } 183 184 simpdata = RTA_DATA(tb[TCA_DEF_DATA]); 185 186 fprintf(f, "Simple <%s>\n", simpdata); 187 fprintf(f, "\t index %u ref %d bind %d", sel->index, 188 sel->refcnt, sel->bindcnt); 189 190 if (show_stats) { 191 if (tb[TCA_DEF_TM]) { 192 struct tcf_t *tm = RTA_DATA(tb[TCA_DEF_TM]); 193 194 print_tm(f, tm); 195 } 196 } 197 fprintf(f, "\n"); 198 199 return 0; 200 } 201 202 struct action_util simple_action_util = { 203 .id = "simple", 204 .parse_aopt = parse_simple, 205 .print_aopt = print_simple, 206 }; 207
