MINOR: frontend: rename sample fetch functions and declare the sample keywords

The following sample fetch functions were only usable by ACLs but are now
usable by sample fetches too :

      fe_conn, fe_id, fe_sess_rate

The fetch functions have been renamed "smp_fetch_*".

doc/configuration.txt

@@ -9636,6 +9636,27 @@ The list of currently supported pattern fetch functions is the following :
                ports to some clients for a whole application session. It is of
                type integer and only works with such tables.
 
+  fe_conn([<frontend>])
+               Returns the number of currently established connections on the
+               the frontend, possibly including the connection being evaluated.
+               If no frontend name is specified, the current one is used. But
+               it is also possible to check another frontend. It can be used to
+               return a sorry page before hard-blocking, or to use a specific
+               backend to drain new requests when the farm is considered full.
+               This is mostly used with ACLs but can also be used to pass some
+               statistics to servers in HTTP headers. See also the "dst_conn",
+               "be_conn", "fe_sess_rate" criteria.
+
+  fe_id        Returns an integer containing the current frontend's id.
+
+  fe_sess_rate([<frontend>])
+               Returns an integer value corresponding to the sessions creation
+               rate on the frontend, in number of new sessions per second. This
+               is used with ACLs to limit the incoming session rate to an
+               acceptable range in order to prevent abuse of service at the
+               earliest moment. It can also be useful to add this element to
+               logs using a log-format directive.
+
   hdr(<name>[,<occ>])
                This extracts the last occurrence of header <name> in an HTTP
                request. Optionally, a specific occurrence might be specified as

src/frontend.c

@@ -1,7 +1,7 @@
 /*
  * Frontend variables and functions.
  *
- * Copyright 2000-2011 Willy Tarreau <w@1wt.eu>
+ * Copyright 2000-2013 Willy Tarreau <w@1wt.eu>
  *
  * This program is free software; you can redistribute it and/or
  * modify it under the terms of the GNU General Public License
@@ -41,6 +41,7 @@
 #include <proto/proto_tcp.h>
 #include <proto/proto_http.h>
 #include <proto/proxy.h>
+#include <proto/sample.h>
 #include <proto/session.h>
 #include <proto/stream_interface.h>
 #include <proto/task.h>
@@ -208,9 +209,13 @@ int frontend_accept(struct session *s)
 	return -1;
 }
 
+/************************************************************************/
+/*      All supported sample and ACL keywords must be declared here.    */
+/************************************************************************/
+
 /* set temp integer to the id of the frontend */
 static int
-acl_fetch_fe_id(struct proxy *px, struct session *l4, void *l7, unsigned int opt,
+smp_fetch_fe_id(struct proxy *px, struct session *l4, void *l7, unsigned int opt,
                 const struct arg *args, struct sample *smp)
 {
 	smp->flags = SMP_F_VOL_SESS;
@@ -224,7 +229,7 @@ acl_fetch_fe_id(struct proxy *px, struct session *l4, void *l7, unsigned int opt
  * an undefined behaviour.
  */
 static int
-acl_fetch_fe_sess_rate(struct proxy *px, struct session *l4, void *l7, unsigned int opt,
+smp_fetch_fe_sess_rate(struct proxy *px, struct session *l4, void *l7, unsigned int opt,
                        const struct arg *args, struct sample *smp)
 {
 	smp->flags = SMP_F_VOL_TEST;
@@ -238,7 +243,7 @@ acl_fetch_fe_sess_rate(struct proxy *px, struct session *l4, void *l7, unsigned
  * an undefined behaviour.
  */
 static int
-acl_fetch_fe_conn(struct proxy *px, struct session *l4, void *l7, unsigned int opt,
+smp_fetch_fe_conn(struct proxy *px, struct session *l4, void *l7, unsigned int opt,
                   const struct arg *args, struct sample *smp)
 {
 	smp->flags = SMP_F_VOL_TEST;
@@ -248,20 +253,32 @@ acl_fetch_fe_conn(struct proxy *px, struct session *l4, void *l7, unsigned int o
 }
 
 
+/* Note: must not be declared <const> as its list will be overwritten.
+ * Please take care of keeping this list alphabetically sorted.
+ */
+static struct sample_fetch_kw_list smp_kws = {{ },{
+	{ "fe_conn",      smp_fetch_fe_conn,      ARG1(1,FE), NULL, SMP_T_UINT, SMP_USE_INTRN, },
+	{ "fe_id",        smp_fetch_fe_id,        0,          NULL, SMP_T_UINT, SMP_USE_FTEND, },
+	{ "fe_sess_rate", smp_fetch_fe_sess_rate, ARG1(1,FE), NULL, SMP_T_UINT, SMP_USE_INTRN, },
+	{ /* END */ },
+}};
+
+
 /* Note: must not be declared <const> as its list will be overwritten.
  * Please take care of keeping this list alphabetically sorted.
  */
 static struct acl_kw_list acl_kws = {{ },{
-	{ "fe_conn",      acl_parse_int, acl_fetch_fe_conn,      acl_match_int, ACL_USE_NOTHING, ARG1(1,FE) },
+	{ "fe_conn",      acl_parse_int, smp_fetch_fe_conn,      acl_match_int, ACL_USE_NOTHING, ARG1(1,FE) },
-	{ "fe_id",        acl_parse_int, acl_fetch_fe_id,        acl_match_int, ACL_USE_NOTHING, 0 },
+	{ "fe_id",        acl_parse_int, smp_fetch_fe_id,        acl_match_int, ACL_USE_NOTHING, 0          },
-	{ "fe_sess_rate", acl_parse_int, acl_fetch_fe_sess_rate, acl_match_int, ACL_USE_NOTHING, ARG1(1,FE) },
+	{ "fe_sess_rate", acl_parse_int, smp_fetch_fe_sess_rate, acl_match_int, ACL_USE_NOTHING, ARG1(1,FE) },
-	{ NULL, NULL, NULL, NULL },
+	{ /* END */ },
 }};
 
 
 __attribute__((constructor))
 static void __frontend_init(void)
 {
+	sample_register_fetches(&smp_kws);
 	acl_register_keywords(&acl_kws);
 }