tc: introduce simple action
Simple action is already in the kernel for years now as an
example. This complements it with user space control.
Signed-off-by: Jamal Hadi Salim <jhs@mojatatu.com>
diff --git a/tc/Makefile b/tc/Makefile
index 1eeabd8..f54a955 100644
--- a/tc/Makefile
+++ b/tc/Makefile
@@ -38,6 +38,7 @@
TCMODULES += m_pedit.o
TCMODULES += m_skbedit.o
TCMODULES += m_csum.o
+TCMODULES += m_simple.o
TCMODULES += p_ip.o
TCMODULES += p_icmp.o
TCMODULES += p_tcp.o
diff --git a/tc/m_simple.c b/tc/m_simple.c
new file mode 100644
index 0000000..0224440
--- /dev/null
+++ b/tc/m_simple.c
@@ -0,0 +1,202 @@
+/*
+ * 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 <jhs@mojatatu.com>
+ *
+ * Pedagogical example. Adds a string that will be printed everytime
+ * 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 <syslog.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 STRING\n"
+ "STRING being an arbitrary string\n"
+ "example: \"simple blah\"\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();
+ simpdata = *argv;
+ ok = 1;
+ argc--;
+ argv++;
+ break;
+ } else if (matches(*argv, "help") == 0) {
+ usage();
+ } else {
+ break;
+ }
+
+ }
+
+ if (!ok) {
+ explain();
+ return -1;
+ }
+
+ if (argc) {
+ if (matches(*argv, "index") == 0) {
+ NEXT_ARG();
+ if (get_u32(&sel.index, *argv, 10)) {
+ fprintf(stderr, "simple: Illegal \"index\"\n");
+ return -1;
+ }
+ argc--;
+ argv++;
+ }
+ }
+
+ if (strlen(simpdata) > (SIMP_MAX_DATA - 1)) {
+ fprintf(stderr, "simple: Illegal string len %ld <%s> \n",
+ strlen(simpdata), simpdata);
+ return -1;
+ }
+
+ sel.action = TC_ACT_PIPE;
+
+ tail = NLMSG_TAIL(n);
+ addattr_l(n, MAX_MSG, tca_id, NULL, 0);
+ addattr_l(n, MAX_MSG, TCA_DEF_PARMS, &sel, sizeof(sel));
+ addattr_l(n, MAX_MSG, TCA_DEF_DATA, simpdata, SIMP_MAX_DATA);
+ tail->rta_len = (char *)NLMSG_TAIL(n) - (char *)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(f, "[NULL simple parameters]");
+ return -1;
+ }
+ sel = RTA_DATA(tb[TCA_DEF_PARMS]);
+
+ if (tb[TCA_DEF_DATA] == NULL) {
+ fprintf(f, "[missing simple string]");
+ return -1;
+ }
+
+ simpdata = RTA_DATA(tb[TCA_DEF_DATA]);
+
+ fprintf(f, "Simple <%s>\n", simpdata);
+ fprintf(f, "\t index %d 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,
+};