IPVS: management of persistence engine modules

This is based heavily on the scheduler management code

Signed-off-by: Simon Horman <horms@verge.net.au>
Acked-by: Julian Anastasov <ja@ssi.bg>

2 files changed, 148 insertions, 1 deletions

diff --git a/net/netfilter/ipvs/Makefile b/net/netfilter/ipvs/Makefile
index 349fe8819b8..4a87bf3c629 100644
--- a/net/netfilter/ipvs/Makefile
+++ b/net/netfilter/ipvs/Makefile
@@ -14,7 +14,7 @@ ip_vs-extra_objs-$(CONFIG_IP_VS_NFCT) += ip_vs_nfct.o
 
 ip_vs-objs :=   ip_vs_conn.o ip_vs_core.o ip_vs_ctl.o ip_vs_sched.o        \
                 ip_vs_xmit.o ip_vs_app.o ip_vs_sync.o                      \
-                ip_vs_est.o ip_vs_proto.o                                  \
+                ip_vs_est.o ip_vs_proto.o ip_vs_pe.o                       \
                 $(ip_vs_proto-objs-y) $(ip_vs-extra_objs-y)
 
 
diff --git a/net/netfilter/ipvs/ip_vs_pe.c b/net/netfilter/ipvs/ip_vs_pe.c
new file mode 100644
index 00000000000..3414af70ee1
--- /dev/null
+++ b/net/netfilter/ipvs/ip_vs_pe.c
@@ -0,0 +1,147 @@
+#define KMSG_COMPONENT "IPVS"
+#define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
+
+#include <linux/module.h>
+#include <linux/spinlock.h>
+#include <linux/interrupt.h>
+#include <asm/string.h>
+#include <linux/kmod.h>
+#include <linux/sysctl.h>
+
+#include <net/ip_vs.h>
+
+/* IPVS pe list */
+static LIST_HEAD(ip_vs_pe);
+
+/* lock for service table */
+static DEFINE_SPINLOCK(ip_vs_pe_lock);
+
+/* Bind a service with a pe */
+void ip_vs_bind_pe(struct ip_vs_service *svc, struct ip_vs_pe *pe)
+{
+        svc->pe = pe;
+}
+
+/* Unbind a service from its pe */
+void ip_vs_unbind_pe(struct ip_vs_service *svc)
+{
+        svc->pe = NULL;
+}
+
+/* Get pe in the pe list by name */
+static struct ip_vs_pe *
+ip_vs_pe_getbyname(const char *pe_name)
+{
+        struct ip_vs_pe *pe;
+
+        IP_VS_DBG(2, "%s(): pe_name \"%s\"\n", __func__,
+                  pe_name);
+
+        spin_lock_bh(&ip_vs_pe_lock);
+
+        list_for_each_entry(pe, &ip_vs_pe, n_list) {
+                /* Test and get the modules atomically */
+                if (pe->module &&
+                    !try_module_get(pe->module)) {
+                        /* This pe is just deleted */
+                        continue;
+                }
+                if (strcmp(pe_name, pe->name)==0) {
+                        /* HIT */
+                        spin_unlock_bh(&ip_vs_pe_lock);
+                        return pe;
+                }
+                if (pe->module)
+                        module_put(pe->module);
+        }
+
+        spin_unlock_bh(&ip_vs_pe_lock);
+        return NULL;
+}
+
+/* Lookup pe and try to load it if it doesn't exist */
+struct ip_vs_pe *ip_vs_pe_get(const char *name)
+{
+        struct ip_vs_pe *pe;
+
+        /* Search for the pe by name */
+        pe = ip_vs_pe_getbyname(name);
+
+        /* If pe not found, load the module and search again */
+        if (!pe) {
+                request_module("ip_vs_pe_%s", name);
+                pe = ip_vs_pe_getbyname(name);
+        }
+
+        return pe;
+}
+
+void ip_vs_pe_put(struct ip_vs_pe *pe)
+{
+        if (pe && pe->module)
+                module_put(pe->module);
+}
+
+/* Register a pe in the pe list */
+int register_ip_vs_pe(struct ip_vs_pe *pe)
+{
+        struct ip_vs_pe *tmp;
+
+        /* increase the module use count */
+        ip_vs_use_count_inc();
+
+        spin_lock_bh(&ip_vs_pe_lock);
+
+        if (!list_empty(&pe->n_list)) {
+                spin_unlock_bh(&ip_vs_pe_lock);
+                ip_vs_use_count_dec();
+                pr_err("%s(): [%s] pe already linked\n",
+                       __func__, pe->name);
+                return -EINVAL;
+        }
+
+        /* Make sure that the pe with this name doesn't exist
+         * in the pe list.
+         */
+        list_for_each_entry(tmp, &ip_vs_pe, n_list) {
+                if (strcmp(tmp->name, pe->name) == 0) {
+                        spin_unlock_bh(&ip_vs_pe_lock);
+                        ip_vs_use_count_dec();
+                        pr_err("%s(): [%s] pe already existed "
+                               "in the system\n", __func__, pe->name);
+                        return -EINVAL;
+                }
+        }
+        /* Add it into the d-linked pe list */
+        list_add(&pe->n_list, &ip_vs_pe);
+        spin_unlock_bh(&ip_vs_pe_lock);
+
+        pr_info("[%s] pe registered.\n", pe->name);
+
+        return 0;
+}
+EXPORT_SYMBOL_GPL(register_ip_vs_pe);
+
+/* Unregister a pe from the pe list */
+int unregister_ip_vs_pe(struct ip_vs_pe *pe)
+{
+        spin_lock_bh(&ip_vs_pe_lock);
+        if (list_empty(&pe->n_list)) {
+                spin_unlock_bh(&ip_vs_pe_lock);
+                pr_err("%s(): [%s] pe is not in the list. failed\n",
+                       __func__, pe->name);
+                return -EINVAL;
+        }
+
+        /* Remove it from the d-linked pe list */
+        list_del(&pe->n_list);
+        spin_unlock_bh(&ip_vs_pe_lock);
+
+        /* decrease the module use count */
+        ip_vs_use_count_dec();
+
+        pr_info("[%s] pe unregistered.\n", pe->name);
+
+        return 0;
+}
+EXPORT_SYMBOL_GPL(unregister_ip_vs_pe);