Weighted Random Policy

examples/load_balancer/load_balancer.c

@@ -95,6 +95,13 @@ struct loadbalance {
 
         /* config file */
         char *cfg_filename;
+
+        /* LB policy */
+        char *policy;
+
+        /* structures to store server weights */
+        int *weights;
+        int total_weight;
 };
 
 /* Struct for backend servers */
@@ -244,9 +251,10 @@ parse_app_args(int argc, char *argv[], const char *progname) {
  */
 static int
 parse_backend_config(void) {
-        int ret, temp, i;
+        int ret, temp, i, weight;
         char ip[32];
         char mac[32];
+        char policy[32];
         FILE *cfg;
 
         cfg = fopen(lb->cfg_filename, "r");
@@ -259,15 +267,25 @@ parse_backend_config(void) {
         }
         lb->server_count = temp;
 
+        lb->weights = (int*)calloc(temp,sizeof(int));
+
         lb->server = (struct backend_server *)rte_malloc("backend server info",
                                                          sizeof(struct backend_server) * lb->server_count, 0);
         if (lb->server == NULL) {
                 rte_exit(EXIT_FAILURE, "Malloc failed, can't allocate server information\n");
         }
 
+        ret = fscanf(cfg, "%s", policy);
+        lb->policy = strdup(policy);
+
+        if (!((!strcmp(lb->policy,"random")) || (!strcmp(lb->policy,"rrobin")) || (!strcmp(lb->policy,"weighted_random")))) {
+                rte_exit(EXIT_FAILURE, "Invalid policy. Check server.conf\n");
+        }
+
         for (i = 0; i < lb->server_count; i++) {
-                ret = fscanf(cfg, "%s %s", ip, mac);
-                if (ret != 2) {
+                ret = fscanf(cfg, "%s %s %d", ip, mac, &weight);
+                if (strcmp(policy, "weighted_random")) weight = 1;
+                if (ret != 3) {
                         rte_exit(EXIT_FAILURE, "Invalid backend config structure\n");
                 }
 
@@ -280,6 +298,9 @@ parse_backend_config(void) {
                 if (ret < 0) {
                         rte_exit(EXIT_FAILURE, "Error parsing config MAC address #%d\n", i);
                 }
+
+                lb->weights[i] = weight;
+                lb->total_weight += weight;
         }
 
         fclose(cfg);
@@ -460,10 +481,34 @@ table_add_entry(struct onvm_ft_ipv4_5tuple *key, struct flow_info **flow) {
         }
 
         lb->num_stored++;
-        data->dest = lb->num_stored % lb->server_count;
+        if (!strcmp(lb->policy,"random")) {
+                time_t t;
+                /* Intializes random number generator */
+                srand((unsigned) time(&t));
+                data->dest = rand() % lb->server_count;
+        }
+        else if (!strcmp(lb->policy,"rrobin")) {
+                data->dest = lb->num_stored % lb->server_count;
+        }
+        else if (!strcmp(lb->policy,"weighted_random")) {
+                time_t t;
+                int i, wrand, cur_weight_sum;
+                /* Intializes random number generator */
+                srand((unsigned) time(&t));
+                wrand = rand() % lb->total_weight;
+                cur_weight_sum=0;
+                for (i = 0; i < lb->server_count; i++) {
+                        cur_weight_sum+=lb->weights[i];
+                        if(wrand < cur_weight_sum) {
+                                data->dest=i;
+                                break;
+                        }
+                }
+
+        }
+
         data->last_pkt_cycles = lb->elapsed_cycles;
         data->is_active = 0;
-
         *flow = data;
 
         return 0;
@@ -644,6 +689,10 @@ main(int argc, char *argv[]) {
         onvm_nflib_run(nf_local_ctx);
 
         onvm_nflib_stop(nf_local_ctx);
+
+		free(lb->weights);
+		free(lb->policy);
+
         onvm_ft_free(lb->ft);
         rte_free(lb);
         printf("If we reach here, program is ending\n");

examples/load_balancer/server.conf

@@ -1,3 +1,4 @@
 LIST_SIZE 2
-10.10.2.1 3c:fd:fe:b4:fa:4c
-10.10.2.3 3c:fd:fe:b0:f1:74
+weighted_random
+10.10.1.2 90:e2:ba:ac:16:34 1
+10.10.1.3 90:e2:ba:b3:bb:7d 7

run_manager.sh

@@ -0,0 +1,7 @@
+#!/usr/bin/bash
+cd /local/onvm/openNetVM/scripts
+source ./setup_cloudlab.sh
+cd /local/onvm/openNetVM
+cd onvm && make && cd ..
+cd examples && make && cd ..
+./onvm/go.sh -k 3 -n 0xFF -s stdout