tc/m_simple.c

   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 <fcntl.h>
  70 #include <sys/socket.h>
  71 #include <netinet/in.h>
  72 #include <arpa/inet.h>
  73 #include <string.h>
  74 #include "utils.h"
  75 #include "tc_util.h"
  76 #include <linux/tc_act/tc_defact.h>
  77
  78 #ifndef SIMP_MAX_DATA
  79 #define SIMP_MAX_DATA   32
  80 #endif
  81 static void explain(void)
  82 {
  83         fprintf(stderr, "Usage:... simple [sdata STRING] [index INDEX] [CONTROL]\n");
  84         fprintf(stderr, "\tSTRING being an arbitrary string\n"
  85                 "\tINDEX := optional index value used\n"
  86                 "\tCONTROL := reclassify|pipe|drop|continue|ok\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         while (argc > 0) {
 107                 if (matches(*argv, "simple") == 0) {
 108                         NEXT_ARG();
 109                 } else if (matches(*argv, "sdata") == 0) {
 110                         NEXT_ARG();
 111                         ok += 1;
 112                         simpdata = *argv;
 113                         argc--;
 114                         argv++;
 115                 } else if (matches(*argv, "help") == 0) {
 116                         usage();
 117                 } else {
 118                         break;
 119                 }
 120         }
 121
 122         if (argc) {
 123                 if (matches(*argv, "index") == 0) {
 124                         NEXT_ARG();
 125                         if (get_u32(&sel.index, *argv, 10)) {
 126                                 fprintf(stderr, "simple: Illegal \"index\" (%s)\n",
 127                                         *argv);
 128                                 return -1;
 129                         }
 130                         ok += 1;
 131                         argc--;
 132                         argv++;
 133                 }
 134         }
 135
 136         if (!ok) {
 137                 explain();
 138                 return -1;
 139         }
 140
 141         if (simpdata && (strlen(simpdata) > (SIMP_MAX_DATA - 1))) {
 142                 fprintf(stderr, "simple: Illegal string len %zu <%s>\n",
 143                         strlen(simpdata), simpdata);
 144                 return -1;
 145         }
 146
 147         sel.action = TC_ACT_PIPE;
 148
 149         tail = addattr_nest(n, MAX_MSG, tca_id);
 150         addattr_l(n, MAX_MSG, TCA_DEF_PARMS, &sel, sizeof(sel));
 151         if (simpdata)
 152                 addattr_l(n, MAX_MSG, TCA_DEF_DATA, simpdata, SIMP_MAX_DATA);
 153         addattr_nest_end(n, tail);
 154
 155         *argc_p = argc;
 156         *argv_p = argv;
 157         return 0;
 158 }
 159
 160 static int print_simple(struct action_util *au, FILE *f, struct rtattr *arg)
 161 {
 162         struct tc_defact *sel;
 163         struct rtattr *tb[TCA_DEF_MAX + 1];
 164         char *simpdata;
 165
 166         if (arg == NULL)
 167                 return -1;
 168
 169         parse_rtattr_nested(tb, TCA_DEF_MAX, arg);
 170
 171         if (tb[TCA_DEF_PARMS] == NULL) {
 172                 fprintf(f, "[NULL simple parameters]");
 173                 return -1;
 174         }
 175         sel = RTA_DATA(tb[TCA_DEF_PARMS]);
 176
 177         if (tb[TCA_DEF_DATA] == NULL) {
 178                 fprintf(f, "[missing simple string]");
 179                 return -1;
 180         }
 181
 182         simpdata = RTA_DATA(tb[TCA_DEF_DATA]);
 183
 184         fprintf(f, "Simple <%s>\n", simpdata);
 185         fprintf(f, "\t index %u ref %d bind %d", sel->index,
 186                 sel->refcnt, sel->bindcnt);
 187
 188         if (show_stats) {
 189                 if (tb[TCA_DEF_TM]) {
 190                         struct tcf_t *tm = RTA_DATA(tb[TCA_DEF_TM]);
 191
 192                         print_tm(f, tm);
 193                 }
 194         }
 195         fprintf(f, "\n");
 196
 197         return 0;
 198 }
 199
 200 struct action_util simple_action_util = {
 201         .id = "simple",
 202         .parse_aopt = parse_simple,
 203         .print_aopt = print_simple,
 204 };