Fix: improved load balancing algorithm

[l2tpns.git] / grpsess.c

diff --git a/grpsess.c b/grpsess.c
index 7f897b3..a4b63ab 100644 (file)
--- a/grpsess.c
+++ b/grpsess.c
@@ -42,6 +42,14 @@ static groupidt grp_lookup_ipmap(in_addr_t ip)
        return h[*a].grp;
 }
 
+typedef struct
+{
+       sessionidt sid_loaddist[0x10000];
+}
+local_group;
+
+local_group *grp_local = NULL;         // Array of local_group structures.
+
 //
 // Take an IP address in HOST byte order and
 // add it to the grouid by IP cache.
@@ -447,6 +455,14 @@ void grp_initdata()
        {
                grpsession[i].state = GROUPEUNDEF;
        }
+
+       if (!(grp_local = shared_malloc(sizeof(local_group) * MAXGROUPE)))
+       {
+               LOG(0, 0, 0, "Error doing malloc for grp_local: %s\n", strerror(errno));
+               exit(1);
+       }
+       memset(grp_local, 0, sizeof(grp_local[0]) * MAXGROUPE);
+
 }
 
 // Update time_changed of the group
@@ -498,7 +514,7 @@ static void grp_uncache_ipsession(groupidt g, sessionidt s)
 }
 
 // return the next session can be used on the group
-sessionidt grp_getnextsession(groupidt g, in_addr_t ip)
+sessionidt grp_getnextsession(groupidt g, in_addr_t ip, in_addr_t ip_src)
 {
        sessionidt s = 0, s2 = 0, s3 = 0;
        int i;
@@ -551,9 +567,30 @@ sessionidt grp_getnextsession(groupidt g, in_addr_t ip)
 
        if ((s = sessionbyip(ip)))
        {
-               if (s == grpsession[g].smax)
+               uint8_t *as = (uint8_t *) &ip_src;
+               uint8_t *ad = (uint8_t *) &ip;
+               uint16_t ai = ad[3];
+               ai <<= 8;
+               ai |= as[3];
+
+               s = grp_local[g].sid_loaddist[ai];
+               if (!s)
+               {
+                       s = grpsession[g].smin;
+                       grp_local[g].sid_loaddist[ai] = s;
+               }
+
+               if (g != grp_groupbysession(s))
+               {
+                       // This session does not belong to this group
+                       LOG(2, s, session[s].tunnel, "Warning, the session does not belong to group %d\n", g);
+                       s = 0;
+                       grp_local[g].sid_loaddist[ai] = 0;
+               }
+               else if (s == grpsession[g].smax)
                {
                        s = grpsession[g].smin;
+                       grp_local[g].sid_loaddist[ai] = s;
                        grpsession[g].smax = 0;
                }
                else if ( (session[s].ppp.phase > Establish) &&
@@ -564,6 +601,7 @@ sessionidt grp_getnextsession(groupidt g, in_addr_t ip)
                else
                {
                        s = 0;
+                       grp_local[g].sid_loaddist[ai] = 0;
                }
        }