[MINOR] backend: separate declarations of LB algos from their lookup method
LB algo macros were composed of the LB algo by itself without any indication
of the method to use to look up a server (the lb function itself). This
method was implied by the LB algo, which was not very convenient to add
more algorithms. Now we have several fields in the LB macros, some to
describe what to look for in the requests, some to describe how to transform
that (kind of algo) and some to describe what lookup function to use.
The next patch will make it possible to factor out some code for all algos
which rely on a map.
diff --git a/include/types/backend.h b/include/types/backend.h
index 7e5b342..a73a36a 100644
--- a/include/types/backend.h
+++ b/include/types/backend.h
@@ -28,27 +28,64 @@
#include <types/lb_map.h>
#include <types/server.h>
-/* Parameters for lbprm.algo.
- * The low part of the value is unique for each algo so that applying the mask
- * BE_LB_ALGO returns a unique algorithm.
- * The high part indicates specific properties.
+/* Parameters for lbprm.algo */
+
+/* Lower bits define the kind of load balancing method, which means the type of
+ * algorithm, and which criterion it is based on. For this reason, those bits
+ * also include information about dependencies, so that the config parser can
+ * detect incompatibilities.
*/
+/* LB parameters. Depends on the LB kind. Right now, only hashing uses this. */
+#define BE_LB_HASH_SRC 0x00000 /* hash source IP */
+#define BE_LB_HASH_URI 0x00001 /* hash HTTP URI */
+#define BE_LB_HASH_PRM 0x00002 /* hash HTTP URL parameter */
+#define BE_LB_HASH_HDR 0x00003 /* hash HTTP header value */
+#define BE_LB_HASH_RDP 0x00004 /* hash RDP cookie value */
+#define BE_LB_PARM 0x000FF /* mask to get/clear the LB param */
+
+/* Required input(s) */
+#define BE_LB_NEED_NONE 0x00000 /* no input needed */
+#define BE_LB_NEED_ADDR 0x00100 /* only source address needed */
+#define BE_LB_NEED_DATA 0x00200 /* some payload is needed */
+#define BE_LB_NEED_HTTP 0x00400 /* an HTTP request is needed */
+/* not used: 0x0800 */
+#define BE_LB_NEED 0x00F00 /* mask to get/clear dependencies */
+
+/* Algorithm */
+#define BE_LB_KIND_NONE 0x00000 /* algorithm not set */
+#define BE_LB_KIND_RR 0x01000 /* round-robin */
+#define BE_LB_KIND_LC 0x02000 /* least connections */
+#define BE_LB_KIND_HI 0x03000 /* hash of input (see hash inputs below) */
+#define BE_LB_KIND 0x07000 /* mask to get/clear LB algorithm */
+
+/* All known variants of load balancing algorithms. These can be cleared using
+ * the BE_LB_ALGO mask. For a check, using BE_LB_KIND is preferred.
+ */
+#define BE_LB_ALGO_NONE (BE_LB_KIND_NONE | BE_LB_NEED_NONE) /* not defined */
+#define BE_LB_ALGO_RR (BE_LB_KIND_RR | BE_LB_NEED_NONE) /* round robin */
+#define BE_LB_ALGO_LC (BE_LB_KIND_LC | BE_LB_NEED_NONE) /* least connections */
+#define BE_LB_ALGO_SH (BE_LB_KIND_HI | BE_LB_NEED_ADDR | BE_LB_HASH_SRC) /* hash: source IP */
+#define BE_LB_ALGO_UH (BE_LB_KIND_HI | BE_LB_NEED_HTTP | BE_LB_HASH_URI) /* hash: HTTP URI */
+#define BE_LB_ALGO_PH (BE_LB_KIND_HI | BE_LB_NEED_HTTP | BE_LB_HASH_PRM) /* hash: HTTP URL parameter */
+#define BE_LB_ALGO_HH (BE_LB_KIND_HI | BE_LB_NEED_HTTP | BE_LB_HASH_HDR) /* hash: HTTP header value */
+#define BE_LB_ALGO_RCH (BE_LB_KIND_HI | BE_LB_NEED_DATA | BE_LB_HASH_RDP) /* hash: RDP cookie value */
+#define BE_LB_ALGO (BE_LB_KIND | BE_LB_NEED | BE_LB_PARM ) /* mask to clear algo */
+
+/* Higher bits define how a given criterion is mapped to a server. In fact it
+ * designates the LB function by itself. The dynamic algorithms will also have
+ * the DYN bit set. These flags are automatically set at the end of the parsing.
+ */
+#define BE_LB_LKUP_NONE 0x00000 /* not defined */
+#define BE_LB_LKUP_MAP 0x10000 /* static map based lookup */
+#define BE_LB_LKUP_RRTREE 0x20000 /* FWRR tree lookup */
+#define BE_LB_LKUP_LCTREE 0x30000 /* FWLC tree lookup */
+#define BE_LB_LKUP 0x70000 /* mask to get just the LKUP value */
+
+/* additional properties */
+#define BE_LB_PROP_DYN 0x80000 /* bit to indicate a dynamic algorithm */
+
-/* Masks to extract algorithm properties */
-#define BE_LB_ALGO 0x000007FF /* mask to extract all algorithm flags */
-#define BE_LB_PROP_DYN 0x00000100 /* mask to match dynamic algorithms */
-#define BE_LB_PROP_L4 0x00000200 /* mask to match layer4-based algorithms */
-#define BE_LB_PROP_L7 0x00000400 /* mask to match layer7-based algorithms */
-/* the algorithms themselves */
-#define BE_LB_ALGO_NONE 0x00000000 /* dispatch or transparent mode */
-#define BE_LB_ALGO_RR (BE_LB_PROP_DYN | 0x01) /* fast weighted round-robin mode (dynamic) */
-#define BE_LB_ALGO_SH (BE_LB_PROP_L4 | 0x02) /* balance on source IP hash */
-#define BE_LB_ALGO_UH (BE_LB_PROP_L7 | 0x03) /* balance on URI hash */
-#define BE_LB_ALGO_PH (BE_LB_PROP_L7 | 0x04) /* balance on URL parameter hash */
-#define BE_LB_ALGO_LC (BE_LB_PROP_DYN | 0x05) /* fast weighted leastconn mode (dynamic) */
-#define BE_LB_ALGO_HH (BE_LB_PROP_L7 | 0x06) /* balance on Http Header value */
-#define BE_LB_ALGO_RCH (BE_LB_PROP_L4 | 0x07) /* balance on RDP Cookie value */
/* various constants */
@@ -64,7 +101,7 @@
/* LB parameters for all algorithms */
struct lbprm {
- int algo; /* load balancing algorithm and variants: BE_LB_ALGO_* */
+ int algo; /* load balancing algorithm and variants: BE_LB_* */
int tot_wact, tot_wbck; /* total effective weights of active and backup servers */
int tot_weight; /* total effective weight of servers participating to LB */
int tot_used; /* total number of servers used for LB */