MySQL sqlippools: Find and allocate stored procedure

raddb/mods-config/sql/ippool/mysql/procedure.sql

@@ -0,0 +1,121 @@
+--
+-- A stored procedure to reallocate a user's previous address, otherwise
+-- provide a free address.
+--
+-- Using this SP reduces the usual set dialogue of queries to a single
+-- query:
+--
+--   START TRANSACTION; SELECT FOR UPDATE; UPDATE; COMMIT;  ->  CALL sp()
+--
+-- The stored procedure is executed on an database instance within a single
+-- round trip which often leads to reduced deadlocking and significant
+-- performance improvements especially on multi-master clusters, perhaps even
+-- by an order of magnitude or more.
+--
+-- To use this stored procedure the corresponding queries.conf statements must
+-- be configured as follows:
+--
+-- allocate_begin = ""
+-- allocate_find = "\
+-- 	CALL sp_allocate_previous_or_new_framedipaddress( \
+-- 		'%{control:${pool_name}}', \
+-- 		'%{User-Name}', \
+-- 		'%{Calling-Station-Id}', \
+-- 		'%{NAS-IP-Address}', \
+-- 		'${pool_key}', \
+-- 		${lease_duration} \
+-- 	)"
+-- allocate_update = ""
+-- allocate_commit = ""
+--
+
+CREATE INDEX poolname_username_callingstationid ON radippool(pool_name,username,callingstationid);
+
+DELIMITER $$
+
+DROP PROCEDURE IF EXISTS sp_allocate_previous_or_new_framedipaddress;
+CREATE PROCEDURE sp_allocate_previous_or_new_framedipaddress (
+        IN v_pool_name VARCHAR(64),
+        IN v_username VARCHAR(64),
+        IN v_callingstationid VARCHAR(64),
+        IN v_nasipaddress VARCHAR(15),
+        IN v_pool_key VARCHAR(64),
+        IN v_lease_duration INT
+)
+proc:BEGIN
+        DECLARE r_address VARCHAR(15);
+
+        SET TRANSACTION ISOLATION LEVEL READ COMMITTED;
+
+        START TRANSACTION;
+
+        -- Reissue an existing IP address lease when re-authenticating a session
+        --
+        SELECT framedipaddress INTO r_address
+        FROM radippool
+        WHERE pool_name = v_pool_name
+                AND expiry_time > NOW()
+                AND username = v_username
+                AND callingstationid = v_callingstationid
+        LIMIT 1
+        FOR UPDATE;
+--      FOR UPDATE SKIP LOCKED;  -- Better performance, but limited support
+
+        -- Reissue an user's previous IP address, provided that the lease is
+        -- available (i.e. enable sticky IPs)
+        --
+        -- When using this SELECT you should delete the one above. You must also
+        -- set allocate_clear = "" in queries.conf to persist the associations
+        -- for expired leases.
+        --
+        -- SELECT framedipaddress INTO r_address
+        -- FROM radippool
+        -- WHERE pool_name = v_pool_name
+        --         AND username = v_username
+        --         AND callingstationid = v_callingstationid
+        -- LIMIT 1
+        -- FOR UPDATE;
+        -- -- FOR UPDATE SKIP LOCKED;  -- Better performance, but limited support
+
+        -- If we didn't reallocate a previous address then pick the least
+        -- recently used address from the pool which maximises the likelihood
+        -- of re-assigning the other addresses to their recent user
+        --
+        IF r_address IS NULL THEN
+                SELECT framedipaddress INTO r_address
+                FROM radippool
+                WHERE pool_name = v_pool_name
+                        AND ( expiry_time < NOW() OR expiry_time IS NULL )
+                ORDER BY
+                        expiry_time
+                LIMIT 1
+                FOR UPDATE;
+--              FOR UPDATE SKIP LOCKED;  -- Better performance, but limited support
+        END IF;
+
+        -- Return nothing if we failed to allocated an address
+        --
+        IF r_address IS NULL THEN
+                COMMIT;
+                LEAVE proc;
+        END IF;
+
+        -- Update the pool having allocated an IP address
+        --
+        UPDATE radippool
+        SET
+                nasipaddress = v_nasipaddress,
+                pool_key = v_pool_key,
+                callingstationid = v_callingstationid,
+                username = v_username,
+                expiry_time = NOW() + INTERVAL v_lease_duration SECOND
+        WHERE framedipaddress = r_address;
+
+        COMMIT;
+
+        -- Return the address that we allocated
+        SELECT r_address;
+
+END$$
+
+DELIMITER ;

raddb/mods-config/sql/ippool/mysql/queries.conf

@@ -116,6 +116,23 @@ allocate_update = "\
 		username = '%{User-Name}', expiry_time = NOW() + INTERVAL ${lease_duration} SECOND \
 	WHERE framedipaddress = '%I'
 
+#
+#  Use a stored procedure to find AND allocate the address. Read and customise
+#  `procedure.sql` in this directory to determine the optimal configuration.
+#
+#allocate_begin = ""
+#allocate_find = "\
+#	CALL sp_allocate_previous_or_new_framedipaddress( \
+#		'%{control:${pool_name}}', \
+#		'%{User-Name}', \
+#		'%{Calling-Station-Id}', \
+#		'%{NAS-IP-Address}', \
+#		'${pool_key}', \
+#		${lease_duration} \
+#	)"
+#allocate_update = ""
+#allocate_commit = ""
+
 #
 #  This series of queries frees an IP number when an accounting START record arrives.
 #