[PATCH] use nf_register_hooks

[Jason Stubbs <j.stubbs@xxxxxxxxxxxxxxx>]

Netfilter contains two nice little functions, nf_register_hooks and 
nf_unregister_hooks, that (un)register a series of hooks and automatically 
handle failure. This patch converts LVS to use these functions so that that 
any future addition/removal of hooks requires less changes and is thus less 
error prone.

-- 
Jason Stubbs <j.stubbs@xxxxxxxxxxxxxxx>
LINKTHINK INC.
東京都渋谷区桜ヶ丘町22-14 N.E.S S棟 3F
TEL 03-5728-4772  FAX 03-5728-4773

--- net/ipv4/ipvs/ip_vs_core.c.orig     2008-04-16 10:48:45.000000000 +0900
+++ net/ipv4/ipvs/ip_vs_core.c  2008-04-16 11:27:46.000000000 +0900
@@ -1025,43 +1025,45 @@ ip_vs_forward_icmp(unsigned int hooknum,
 }
 
 
-/* After packet filtering, forward packet through VS/DR, VS/TUN,
-   or VS/NAT(change destination), so that filtering rules can be
-   applied to IPVS. */
-static struct nf_hook_ops ip_vs_in_ops = {
-       .hook           = ip_vs_in,
-       .owner          = THIS_MODULE,
-       .pf             = PF_INET,
-       .hooknum        = NF_IP_LOCAL_IN,
-       .priority       = 100,
-};
-
-/* After packet filtering, change source only for VS/NAT */
-static struct nf_hook_ops ip_vs_out_ops = {
-       .hook           = ip_vs_out,
-       .owner          = THIS_MODULE,
-       .pf             = PF_INET,
-       .hooknum        = NF_IP_FORWARD,
-       .priority       = 100,
-};
-
-/* After packet filtering (but before ip_vs_out_icmp), catch icmp
-   destined for 0.0.0.0/0, which is for incoming IPVS connections */
-static struct nf_hook_ops ip_vs_forward_icmp_ops = {
-       .hook           = ip_vs_forward_icmp,
-       .owner          = THIS_MODULE,
-       .pf             = PF_INET,
-       .hooknum        = NF_IP_FORWARD,
-       .priority       = 99,
-};
-
-/* Before the netfilter connection tracking, exit from POST_ROUTING */
-static struct nf_hook_ops ip_vs_post_routing_ops = {
-       .hook           = ip_vs_post_routing,
-       .owner          = THIS_MODULE,
-       .pf             = PF_INET,
-       .hooknum        = NF_IP_POST_ROUTING,
-       .priority       = NF_IP_PRI_NAT_SRC-1,
+static struct nf_hook_ops ip_vs_ops[] = {
+       /* After packet filtering, forward packet through VS/DR, VS/TUN,
+          or VS/NAT(change destination), so that filtering rules can be
+          applied to IPVS. */
+       {
+               .hook           = ip_vs_in,
+               .owner          = THIS_MODULE,
+               .pf             = PF_INET,
+               .hooknum        = NF_IP_LOCAL_IN,
+               .priority       = 100,
+       },
+
+       /* After packet filtering, change source only for VS/NAT */
+       {
+               .hook           = ip_vs_out,
+               .owner          = THIS_MODULE,
+               .pf             = PF_INET,
+               .hooknum        = NF_IP_FORWARD,
+               .priority       = 100,
+       },
+
+       /* After packet filtering (but before ip_vs_out_icmp), catch icmp
+          destined for 0.0.0.0/0, which is for incoming IPVS connections */
+       {
+               .hook           = ip_vs_forward_icmp,
+               .owner          = THIS_MODULE,
+               .pf             = PF_INET,
+               .hooknum        = NF_IP_FORWARD,
+               .priority       = 99,
+       },
+
+       /* Before the netfilter connection tracking, exit from POST_ROUTING */
+       {
+               .hook           = ip_vs_post_routing,
+               .owner          = THIS_MODULE,
+               .pf             = PF_INET,
+               .hooknum        = NF_IP_POST_ROUTING,
+               .priority       = NF_IP_PRI_NAT_SRC-1,
+       }
 };
 
 
@@ -1092,37 +1094,15 @@ static int __init ip_vs_init(void)
                goto cleanup_app;
        }
 
-       ret = nf_register_hook(&ip_vs_in_ops);
+       ret = nf_register_hooks(ip_vs_ops, sizeof(ip_vs_ops) / sizeof(struct 
nf_hook_ops));
        if (ret < 0) {
-               IP_VS_ERR("can't register in hook.\n");
+               IP_VS_ERR("can't register hooks.\n");
                goto cleanup_conn;
        }
 
-       ret = nf_register_hook(&ip_vs_out_ops);
-       if (ret < 0) {
-               IP_VS_ERR("can't register out hook.\n");
-               goto cleanup_inops;
-       }
-       ret = nf_register_hook(&ip_vs_post_routing_ops);
-       if (ret < 0) {
-               IP_VS_ERR("can't register post_routing hook.\n");
-               goto cleanup_outops;
-       }
-       ret = nf_register_hook(&ip_vs_forward_icmp_ops);
-       if (ret < 0) {
-               IP_VS_ERR("can't register forward_icmp hook.\n");
-               goto cleanup_postroutingops;
-       }
-
        IP_VS_INFO("ipvs loaded.\n");
        return ret;
 
-  cleanup_postroutingops:
-       nf_unregister_hook(&ip_vs_post_routing_ops);
-  cleanup_outops:
-       nf_unregister_hook(&ip_vs_out_ops);
-  cleanup_inops:
-       nf_unregister_hook(&ip_vs_in_ops);
   cleanup_conn:
        ip_vs_conn_cleanup();
   cleanup_app:
@@ -1136,10 +1116,7 @@ static int __init ip_vs_init(void)
 
 static void __exit ip_vs_cleanup(void)
 {
-       nf_unregister_hook(&ip_vs_forward_icmp_ops);
-       nf_unregister_hook(&ip_vs_post_routing_ops);
-       nf_unregister_hook(&ip_vs_out_ops);
-       nf_unregister_hook(&ip_vs_in_ops);
+       nf_unregister_hooks(ip_vs_ops, sizeof(ip_vs_ops) / sizeof(struct 
nf_hook_ops));
        ip_vs_conn_cleanup();
        ip_vs_app_cleanup();
        ip_vs_protocol_cleanup();