MINOR: action: Add function to check rules using an action ACT_ACTION_TRK_*

The function "check_trk_action" has been added to find and check the target
table for rules using an action ACT_ACTION_TRK_*.
diff --git a/Makefile b/Makefile
index 0ab3067..c79e4ae 100644
--- a/Makefile
+++ b/Makefile
@@ -843,7 +843,7 @@
        src/regex.o src/queue.o src/frontend.o src/arg.o src/proto_uxst.o \
        src/raw_sock.o src/lb_chash.o src/lb_fwlc.o src/lb_fwrr.o \
        src/lb_fas.o src/applet.o src/hdr_idx.o src/ev_select.o src/hash.o \
-       src/lb_map.o src/base64.o src/sha1.o src/protocol.o src/h1.o
+       src/lb_map.o src/base64.o src/sha1.o src/protocol.o src/h1.o src/action.o
 
 EBTREE_OBJS = $(EBTREE_DIR)/ebtree.o \
               $(EBTREE_DIR)/eb32tree.o $(EBTREE_DIR)/eb64tree.o \
diff --git a/include/proto/action.h b/include/proto/action.h
index ce94aa0..e3015ec 100644
--- a/include/proto/action.h
+++ b/include/proto/action.h
@@ -76,4 +76,12 @@
 	return trk_action - ACT_ACTION_TRK_SC0;
 }
 
+/* Find and check the target table used by an action ACT_ACTION_TRK_*. This
+ * function should be called during the configuration validity check.
+ *
+ * The function returns 1 in success case, otherwise, it returns 0 and err is
+ * filled.
+ */
+int check_trk_action(struct act_rule *rule, struct proxy *px, char **err);
+
 #endif /* _PROTO_ACTION_H */
diff --git a/src/action.c b/src/action.c
new file mode 100644
index 0000000..54d27a0
--- /dev/null
+++ b/src/action.c
@@ -0,0 +1,64 @@
+/*
+ * Action management functions.
+ *
+ * Copyright 2017 HAProxy Technologies, Christopher Faulet <cfaulet@haproxy.com>
+ *
+ * This program is free software; you can redistribute 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.
+ *
+ */
+
+#include <common/config.h>
+#include <common/memory.h>
+#include <common/mini-clist.h>
+#include <common/standard.h>
+
+#include <proto/action.h>
+#include <proto/proxy.h>
+#include <proto/stick_table.h>
+
+
+/* Find and check the target table used by an action ACT_ACTION_TRK_*. This
+ * function should be called during the configuration validity check.
+ *
+ * The function returns 1 in success case, otherwise, it returns 0 and err is
+ * filled.
+ */
+int check_trk_action(struct act_rule *rule, struct proxy *px, char **err)
+{
+	struct proxy *target;
+
+	if (rule->arg.trk_ctr.table.n)
+		target = proxy_tbl_by_name(rule->arg.trk_ctr.table.n);
+	else
+		target = px;
+
+	if (!target) {
+		memprintf(err, "unable to find table '%s' referenced by track-sc%d",
+			  rule->arg.trk_ctr.table.n, trk_idx(rule->action));
+		return 0;
+	}
+	else if (target->table.size == 0) {
+		memprintf(err, "table '%s' used but not configured",
+			  rule->arg.trk_ctr.table.n ? rule->arg.trk_ctr.table.n : px->id);
+		return 0;
+	}
+	else if (!stktable_compatible_sample(rule->arg.trk_ctr.expr,  target->table.type)) {
+		memprintf(err, "stick-table '%s' uses a type incompatible with the 'track-sc%d' rule",
+			  rule->arg.trk_ctr.table.n ? rule->arg.trk_ctr.table.n : px->id,
+			  trk_idx(rule->action));
+		return 0;
+	}
+	else {
+		free(rule->arg.trk_ctr.table.n);
+		rule->arg.trk_ctr.table.t = &target->table;
+		/* Note: if we decide to enhance the track-sc syntax, we may be
+		 * able to pass a list of counters to track and allocate them
+		 * right here using stktable_alloc_data_type().
+		 */
+	}
+	return 1;
+}
+
diff --git a/src/proto_http.c b/src/proto_http.c
index 23f683c..3c37ade 100644
--- a/src/proto_http.c
+++ b/src/proto_http.c
@@ -8404,6 +8404,7 @@
 		}
 		rule->arg.trk_ctr.expr = expr;
 		rule->action = ACT_ACTION_TRK_SC0 + args[0][8] - '0';
+		rule->check_ptr = check_trk_action;
 	} else if (strcmp(args[0], "redirect") == 0) {
 		struct redirect_rule *redir;
 		char *errmsg = NULL;
@@ -9008,6 +9009,7 @@
 		}
 		rule->arg.trk_ctr.expr = expr;
 		rule->action = ACT_ACTION_TRK_SC0 + args[0][8] - '0';
+		rule->check_ptr = check_trk_action;
 	} else if (((custom = action_http_res_custom(args[0])) != NULL)) {
 		char *errmsg = NULL;
 		cur_arg = 1;
diff --git a/src/tcp_rules.c b/src/tcp_rules.c
index d15b153..f259d51 100644
--- a/src/tcp_rules.c
+++ b/src/tcp_rules.c
@@ -773,6 +773,7 @@
 		}
 		rule->arg.trk_ctr.expr = expr;
 		rule->action = ACT_ACTION_TRK_SC0 + args[kw][8] - '0';
+		rule->check_ptr = check_trk_action;
 	}
 	else if (strcmp(args[arg], "expect-proxy") == 0) {
 		if (strcmp(args[arg+1], "layer4") != 0) {