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 1eeabd8c89c57b2b77c71dfd55bd20aeafb262ab..f54a955b046d81810aa0be4b850da050313c79a8 100644 (file)
--- a/tc/Makefile
+++ b/tc/Makefile
@@ -38,6 +38,7 @@ TCMODULES += m_nat.o
 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 (file)
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,
+};