/* * m_simple.c simple action * * This program is free software; you can distribute it and/or * modify it under the terms of the GNU General Public License * as published by the Free Software Foundation; either version * 2 of the License, or (at your option) any later version. * * Authors: J Hadi Salim * * 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 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 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 #include #include #include #include #include #include #include #include "utils.h" #include "tc_util.h" #include #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(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(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 -1; 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]); fprintf(f, "Simple <%s>\n", simpdata); fprintf(f, "\t index %u ref %d bind %d", sel->index, sel->refcnt, sel->bindcnt); if (show_stats) { if (tb[TCA_DEF_TM]) { struct tcf_t *tm = RTA_DATA(tb[TCA_DEF_TM]); print_tm(f, tm); } } fprintf(f, "\n"); return 0; } struct action_util simple_action_util = { .id = "simple", .parse_aopt = parse_simple, .print_aopt = print_simple, };