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Diffstat (limited to 'tc/m_simple.c')
| -rw-r--r-- | tc/m_simple.c | 202 |
1 files changed, 202 insertions, 0 deletions
diff --git a/tc/m_simple.c b/tc/m_simple.c new file mode 100644 index 0000000..fe2bca2 --- /dev/null +++ b/tc/m_simple.c @@ -0,0 +1,202 @@ +/* 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(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 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]); + + 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); + } + } + print_nl(); + + return 0; +} + +struct action_util simple_action_util = { + .id = "simple", + .parse_aopt = parse_simple, + .print_aopt = print_simple, +}; |