When IP_VS schedulers do not find a destination, they output a terse
"WLC: no destination available" message through kernel syslog, which I
can not only make sense of because syslog puts them in a logfile
together with keepalived checker results.
This patch makes the output a bit more informative, by telling you which
virtual service failed to find a destination.
Example output:
kernel: [
1539214.552233] IPVS: wlc: TCP 192.168.8.30:22 - no destination available
kernel: [
1539299.674418] IPVS: wlc: FWM 22 0x00000016 - no destination available
I have tested the code for IPv4 and FWM services, as you can see from
the example; I do not have an IPv6 setup to test the third code path
with.
To avoid code duplication, I put a new function ip_vs_scheduler_err()
into ip_vs_sched.c, and use that from the schedulers instead of calling
IP_VS_ERR_RL directly.
Signed-off-by: Patrick Schaaf <netdev@bof.de>
Signed-off-by: Simon Horman <horms@verge.net.au>
 extern int ip_vs_leave(struct ip_vs_service *svc, struct sk_buff *skb,
                        struct ip_vs_proto_data *pd);
 
+extern void ip_vs_scheduler_err(struct ip_vs_service *svc, const char *msg);
+
 
 /*
  *      IPVS control data and functions (from ip_vs_ctl.c)
 
        /* No cache entry or it is invalid, time to schedule */
        dest = __ip_vs_lblc_schedule(svc);
        if (!dest) {
-               IP_VS_ERR_RL("LBLC: no destination available\n");
+               ip_vs_scheduler_err(svc, "no destination available");
                return NULL;
        }
 
 
                /* The cache entry is invalid, time to schedule */
                dest = __ip_vs_lblcr_schedule(svc);
                if (!dest) {
-                       IP_VS_ERR_RL("LBLCR: no destination available\n");
+                       ip_vs_scheduler_err(svc, "no destination available");
                        read_unlock(&svc->sched_lock);
                        return NULL;
                }
 
        }
 
        if (!least)
-               IP_VS_ERR_RL("LC: no destination available\n");
+               ip_vs_scheduler_err(svc, "no destination available");
        else
                IP_VS_DBG_BUF(6, "LC: server %s:%u activeconns %d "
                              "inactconns %d\n",
 
        }
 
        if (!least) {
-               IP_VS_ERR_RL("NQ: no destination available\n");
+               ip_vs_scheduler_err(svc, "no destination available");
                return NULL;
        }
 
 
                q = q->next;
        } while (q != p);
        write_unlock(&svc->sched_lock);
-       IP_VS_ERR_RL("RR: no destination available\n");
+       ip_vs_scheduler_err(svc, "no destination available");
        return NULL;
 
   out:
 
 
 #include <net/ip_vs.h>
 
+EXPORT_SYMBOL(ip_vs_scheduler_err);
 /*
  *  IPVS scheduler list
  */
                module_put(scheduler->module);
 }
 
+/*
+ * Common error output helper for schedulers
+ */
+
+void ip_vs_scheduler_err(struct ip_vs_service *svc, const char *msg)
+{
+       if (svc->fwmark) {
+               IP_VS_ERR_RL("%s: FWM %u 0x%08X - %s\n",
+                            svc->scheduler->name, svc->fwmark,
+                            svc->fwmark, msg);
+#ifdef CONFIG_IP_VS_IPV6
+       } else if (svc->af == AF_INET6) {
+               IP_VS_ERR_RL("%s: %s [%pI6]:%d - %s\n",
+                            svc->scheduler->name,
+                            ip_vs_proto_name(svc->protocol),
+                            &svc->addr.in6, ntohs(svc->port), msg);
+#endif
+       } else {
+               IP_VS_ERR_RL("%s: %s %pI4:%d - %s\n",
+                            svc->scheduler->name,
+                            ip_vs_proto_name(svc->protocol),
+                            &svc->addr.ip, ntohs(svc->port), msg);
+       }
+}
 
 /*
  *  Register a scheduler in the scheduler list
 
                        goto nextstage;
                }
        }
-       IP_VS_ERR_RL("SED: no destination available\n");
+       ip_vs_scheduler_err(svc, "no destination available");
        return NULL;
 
        /*
 
            || !(dest->flags & IP_VS_DEST_F_AVAILABLE)
            || atomic_read(&dest->weight) <= 0
            || is_overloaded(dest)) {
-               IP_VS_ERR_RL("SH: no destination available\n");
+               ip_vs_scheduler_err(svc, "no destination available");
                return NULL;
        }
 
 
                        goto nextstage;
                }
        }
-       IP_VS_ERR_RL("WLC: no destination available\n");
+       ip_vs_scheduler_err(svc, "no destination available");
        return NULL;
 
        /*
 
 
                        if (mark->cl == mark->cl->next) {
                                /* no dest entry */
-                               IP_VS_ERR_RL("WRR: no destination available: "
-                                            "no destinations present\n");
+                               ip_vs_scheduler_err(svc,
+                                       "no destination available: "
+                                       "no destinations present");
                                dest = NULL;
                                goto out;
                        }
                                 */
                                if (mark->cw == 0) {
                                        mark->cl = &svc->destinations;
-                                       IP_VS_ERR_RL("WRR: no destination "
-                                                    "available\n");
+                                       ip_vs_scheduler_err(svc,
+                                               "no destination available");
                                        dest = NULL;
                                        goto out;
                                }
                        /* back to the start, and no dest is found.
                           It is only possible when all dests are OVERLOADED */
                        dest = NULL;
-                       IP_VS_ERR_RL("WRR: no destination available: "
-                                    "all destinations are overloaded\n");
+                       ip_vs_scheduler_err(svc,
+                               "no destination available: "
+                               "all destinations are overloaded");
                        goto out;
                }
        }