From 2b95efe7f6bb750256a702cc32d33b0cb2cd8223 Mon Sep 17 00:00:00 2001 From: Jan Engelhardt Date: Wed, 17 Jun 2009 13:57:48 +0200 Subject: [PATCH] netfilter: xtables: use xt_table for hook instantiation The respective xt_table structures already have most of the metadata needed for hook setup. Add a 'priority' field to struct xt_table so that xt_hook_link() can be called with a reduced number of arguments. So should we be having more tables in the future, it comes at no static cost (only runtime, as before) - space saved: 6807373->6806555. Signed-off-by: Jan Engelhardt --- include/linux/netfilter/x_tables.h | 4 +++ net/ipv4/netfilter/arptable_filter.c | 33 +++++---------------- net/ipv4/netfilter/iptable_filter.c | 33 +++++---------------- net/ipv4/netfilter/iptable_mangle.c | 47 +++++------------------------ net/ipv4/netfilter/iptable_raw.c | 27 +++++------------ net/ipv4/netfilter/iptable_security.c | 33 +++++---------------- net/ipv6/netfilter/ip6table_filter.c | 33 +++++---------------- net/ipv6/netfilter/ip6table_mangle.c | 48 +++++------------------------- net/ipv6/netfilter/ip6table_raw.c | 26 +++++----------- net/ipv6/netfilter/ip6table_security.c | 33 +++++---------------- net/netfilter/x_tables.c | 54 ++++++++++++++++++++++++++++++++++ 11 files changed, 121 insertions(+), 250 deletions(-) diff --git a/include/linux/netfilter/x_tables.h b/include/linux/netfilter/x_tables.h index 365fabe..fdd3342 100644 --- a/include/linux/netfilter/x_tables.h +++ b/include/linux/netfilter/x_tables.h @@ -361,6 +361,7 @@ struct xt_table { struct module *me; u_int8_t af; /* address/protocol family */ + int priority; /* hook order */ /* A unique name... */ const char name[XT_TABLE_MAXNAMELEN]; @@ -522,6 +523,9 @@ static inline unsigned long ifname_compare_aligned(const char *_a, return ret; } +extern struct nf_hook_ops *xt_hook_link(const struct xt_table *, nf_hookfn *); +extern void xt_hook_unlink(const struct xt_table *, struct nf_hook_ops *); + #ifdef CONFIG_COMPAT #include diff --git a/net/ipv4/netfilter/arptable_filter.c b/net/ipv4/netfilter/arptable_filter.c index deeda9b..b361de0 100644 --- a/net/ipv4/netfilter/arptable_filter.c +++ b/net/ipv4/netfilter/arptable_filter.c @@ -50,6 +50,7 @@ static const struct xt_table packet_filter = { .valid_hooks = FILTER_VALID_HOOKS, .me = THIS_MODULE, .af = NFPROTO_ARP, + .priority = NF_IP_PRI_FILTER, }; /* The work comes in here from netfilter.c */ @@ -63,29 +64,7 @@ arptable_filter_hook(unsigned int hook, struct sk_buff *skb, return arpt_do_table(skb, hook, in, out, net->ipv4.arptable_filter); } -static struct nf_hook_ops arpt_ops[] __read_mostly = { - { - .hook = arptable_filter_hook, - .owner = THIS_MODULE, - .pf = NFPROTO_ARP, - .hooknum = NF_ARP_IN, - .priority = NF_IP_PRI_FILTER, - }, - { - .hook = arptable_filter_hook, - .owner = THIS_MODULE, - .pf = NFPROTO_ARP, - .hooknum = NF_ARP_OUT, - .priority = NF_IP_PRI_FILTER, - }, - { - .hook = arptable_filter_hook, - .owner = THIS_MODULE, - .pf = NFPROTO_ARP, - .hooknum = NF_ARP_FORWARD, - .priority = NF_IP_PRI_FILTER, - }, -}; +static struct nf_hook_ops *arpfilter_ops __read_mostly; static int __net_init arptable_filter_net_init(struct net *net) { @@ -115,9 +94,11 @@ static int __init arptable_filter_init(void) if (ret < 0) return ret; - ret = nf_register_hooks(arpt_ops, ARRAY_SIZE(arpt_ops)); - if (ret < 0) + arpfilter_ops = xt_hook_link(&packet_filter, arptable_filter_hook); + if (IS_ERR(arpfilter_ops)) { + ret = PTR_ERR(arpfilter_ops); goto cleanup_table; + } return ret; cleanup_table: @@ -127,7 +108,7 @@ cleanup_table: static void __exit arptable_filter_fini(void) { - nf_unregister_hooks(arpt_ops, ARRAY_SIZE(arpt_ops)); + xt_hook_unlink(&packet_filter, arpfilter_ops); unregister_pernet_subsys(&arptable_filter_net_ops); } diff --git a/net/ipv4/netfilter/iptable_filter.c b/net/ipv4/netfilter/iptable_filter.c index 1bfeaae..c14bb85 100644 --- a/net/ipv4/netfilter/iptable_filter.c +++ b/net/ipv4/netfilter/iptable_filter.c @@ -58,6 +58,7 @@ static const struct xt_table packet_filter = { .valid_hooks = FILTER_VALID_HOOKS, .me = THIS_MODULE, .af = NFPROTO_IPV4, + .priority = NF_IP_PRI_FILTER, }; static unsigned int @@ -77,29 +78,7 @@ iptable_filter_hook(unsigned int hook, struct sk_buff *skb, return ipt_do_table(skb, hook, in, out, net->ipv4.iptable_filter); } -static struct nf_hook_ops ipt_ops[] __read_mostly = { - { - .hook = iptable_filter_hook, - .owner = THIS_MODULE, - .pf = NFPROTO_IPV4, - .hooknum = NF_INET_LOCAL_IN, - .priority = NF_IP_PRI_FILTER, - }, - { - .hook = iptable_filter_hook, - .owner = THIS_MODULE, - .pf = NFPROTO_IPV4, - .hooknum = NF_INET_FORWARD, - .priority = NF_IP_PRI_FILTER, - }, - { - .hook = iptable_filter_hook, - .owner = THIS_MODULE, - .pf = NFPROTO_IPV4, - .hooknum = NF_INET_LOCAL_OUT, - .priority = NF_IP_PRI_FILTER, - }, -}; +static struct nf_hook_ops *filter_ops __read_mostly; /* Default to forward because I got too much mail already. */ static int forward = NF_ACCEPT; @@ -142,9 +121,11 @@ static int __init iptable_filter_init(void) return ret; /* Register hooks */ - ret = nf_register_hooks(ipt_ops, ARRAY_SIZE(ipt_ops)); - if (ret < 0) + filter_ops = xt_hook_link(&packet_filter, iptable_filter_hook); + if (IS_ERR(filter_ops)) { + ret = PTR_ERR(filter_ops); goto cleanup_table; + } return ret; @@ -155,7 +136,7 @@ static int __init iptable_filter_init(void) static void __exit iptable_filter_fini(void) { - nf_unregister_hooks(ipt_ops, ARRAY_SIZE(ipt_ops)); + xt_hook_unlink(&packet_filter, filter_ops); unregister_pernet_subsys(&iptable_filter_net_ops); } diff --git a/net/ipv4/netfilter/iptable_mangle.c b/net/ipv4/netfilter/iptable_mangle.c index 4e699cd..2355a22 100644 --- a/net/ipv4/netfilter/iptable_mangle.c +++ b/net/ipv4/netfilter/iptable_mangle.c @@ -69,6 +69,7 @@ static const struct xt_table packet_mangler = { .valid_hooks = MANGLE_VALID_HOOKS, .me = THIS_MODULE, .af = NFPROTO_IPV4, + .priority = NF_IP_PRI_MANGLE, }; static unsigned int @@ -129,43 +130,7 @@ iptable_mangle_hook(unsigned int hook, dev_net(in)->ipv4.iptable_mangle); } -static struct nf_hook_ops ipt_ops[] __read_mostly = { - { - .hook = iptable_mangle_hook, - .owner = THIS_MODULE, - .pf = NFPROTO_IPV4, - .hooknum = NF_INET_PRE_ROUTING, - .priority = NF_IP_PRI_MANGLE, - }, - { - .hook = iptable_mangle_hook, - .owner = THIS_MODULE, - .pf = NFPROTO_IPV4, - .hooknum = NF_INET_LOCAL_IN, - .priority = NF_IP_PRI_MANGLE, - }, - { - .hook = iptable_mangle_hook, - .owner = THIS_MODULE, - .pf = NFPROTO_IPV4, - .hooknum = NF_INET_FORWARD, - .priority = NF_IP_PRI_MANGLE, - }, - { - .hook = iptable_mangle_hook, - .owner = THIS_MODULE, - .pf = NFPROTO_IPV4, - .hooknum = NF_INET_LOCAL_OUT, - .priority = NF_IP_PRI_MANGLE, - }, - { - .hook = iptable_mangle_hook, - .owner = THIS_MODULE, - .pf = NFPROTO_IPV4, - .hooknum = NF_INET_POST_ROUTING, - .priority = NF_IP_PRI_MANGLE, - }, -}; +static struct nf_hook_ops *mangle_ops __read_mostly; static int __net_init iptable_mangle_net_init(struct net *net) { @@ -196,9 +161,11 @@ static int __init iptable_mangle_init(void) return ret; /* Register hooks */ - ret = nf_register_hooks(ipt_ops, ARRAY_SIZE(ipt_ops)); - if (ret < 0) + mangle_ops = xt_hook_link(&packet_mangler, iptable_mangle_hook); + if (IS_ERR(mangle_ops)) { + ret = PTR_ERR(mangle_ops); goto cleanup_table; + } return ret; @@ -209,7 +176,7 @@ static int __init iptable_mangle_init(void) static void __exit iptable_mangle_fini(void) { - nf_unregister_hooks(ipt_ops, ARRAY_SIZE(ipt_ops)); + xt_hook_unlink(&packet_mangler, mangle_ops); unregister_pernet_subsys(&iptable_mangle_net_ops); } diff --git a/net/ipv4/netfilter/iptable_raw.c b/net/ipv4/netfilter/iptable_raw.c index d16e437..62a9915 100644 --- a/net/ipv4/netfilter/iptable_raw.c +++ b/net/ipv4/netfilter/iptable_raw.c @@ -41,6 +41,7 @@ static const struct xt_table packet_raw = { .valid_hooks = RAW_VALID_HOOKS, .me = THIS_MODULE, .af = NFPROTO_IPV4, + .priority = NF_IP_PRI_RAW, }; /* The work comes in here from netfilter.c. */ @@ -61,23 +62,7 @@ iptable_raw_hook(unsigned int hook, struct sk_buff *skb, return ipt_do_table(skb, hook, in, out, net->ipv4.iptable_raw); } -/* 'raw' is the very first table. */ -static struct nf_hook_ops ipt_ops[] __read_mostly = { - { - .hook = iptable_raw_hook, - .pf = NFPROTO_IPV4, - .hooknum = NF_INET_PRE_ROUTING, - .priority = NF_IP_PRI_RAW, - .owner = THIS_MODULE, - }, - { - .hook = iptable_raw_hook, - .pf = NFPROTO_IPV4, - .hooknum = NF_INET_LOCAL_OUT, - .priority = NF_IP_PRI_RAW, - .owner = THIS_MODULE, - }, -}; +static struct nf_hook_ops *rawtable_ops __read_mostly; static int __net_init iptable_raw_net_init(struct net *net) { @@ -108,9 +93,11 @@ static int __init iptable_raw_init(void) return ret; /* Register hooks */ - ret = nf_register_hooks(ipt_ops, ARRAY_SIZE(ipt_ops)); - if (ret < 0) + rawtable_ops = xt_hook_link(&packet_raw, iptable_raw_hook); + if (IS_ERR(rawtable_ops)) { + ret = PTR_ERR(rawtable_ops); goto cleanup_table; + } return ret; @@ -121,7 +108,7 @@ static int __init iptable_raw_init(void) static void __exit iptable_raw_fini(void) { - nf_unregister_hooks(ipt_ops, ARRAY_SIZE(ipt_ops)); + xt_hook_unlink(&packet_raw, rawtable_ops); unregister_pernet_subsys(&iptable_raw_net_ops); } diff --git a/net/ipv4/netfilter/iptable_security.c b/net/ipv4/netfilter/iptable_security.c index 324505a..b1bf3ca 100644 --- a/net/ipv4/netfilter/iptable_security.c +++ b/net/ipv4/netfilter/iptable_security.c @@ -62,6 +62,7 @@ static const struct xt_table security_table = { .valid_hooks = SECURITY_VALID_HOOKS, .me = THIS_MODULE, .af = NFPROTO_IPV4, + .priority = NF_IP_PRI_SECURITY, }; static unsigned int @@ -82,29 +83,7 @@ iptable_security_hook(unsigned int hook, struct sk_buff *skb, return ipt_do_table(skb, hook, in, out, net->ipv4.iptable_security); } -static struct nf_hook_ops ipt_ops[] __read_mostly = { - { - .hook = iptable_security_hook, - .owner = THIS_MODULE, - .pf = NFPROTO_IPV4, - .hooknum = NF_INET_LOCAL_IN, - .priority = NF_IP_PRI_SECURITY, - }, - { - .hook = iptable_security_hook, - .owner = THIS_MODULE, - .pf = NFPROTO_IPV4, - .hooknum = NF_INET_FORWARD, - .priority = NF_IP_PRI_SECURITY, - }, - { - .hook = iptable_security_hook, - .owner = THIS_MODULE, - .pf = NFPROTO_IPV4, - .hooknum = NF_INET_LOCAL_OUT, - .priority = NF_IP_PRI_SECURITY, - }, -}; +static struct nf_hook_ops *sectbl_ops __read_mostly; static int __net_init iptable_security_net_init(struct net *net) { @@ -135,9 +114,11 @@ static int __init iptable_security_init(void) if (ret < 0) return ret; - ret = nf_register_hooks(ipt_ops, ARRAY_SIZE(ipt_ops)); - if (ret < 0) + sectbl_ops = xt_hook_link(&security_table, iptable_security_hook); + if (IS_ERR(sectbl_ops)) { + ret = PTR_ERR(sectbl_ops); goto cleanup_table; + } return ret; @@ -148,7 +129,7 @@ cleanup_table: static void __exit iptable_security_fini(void) { - nf_unregister_hooks(ipt_ops, ARRAY_SIZE(ipt_ops)); + xt_hook_unlink(&security_table, sectbl_ops); unregister_pernet_subsys(&iptable_security_net_ops); } diff --git a/net/ipv6/netfilter/ip6table_filter.c b/net/ipv6/netfilter/ip6table_filter.c index 866f34a..6e95d06 100644 --- a/net/ipv6/netfilter/ip6table_filter.c +++ b/net/ipv6/netfilter/ip6table_filter.c @@ -56,6 +56,7 @@ static const struct xt_table packet_filter = { .valid_hooks = FILTER_VALID_HOOKS, .me = THIS_MODULE, .af = NFPROTO_IPV6, + .priority = NF_IP6_PRI_FILTER, }; /* The work comes in here from netfilter.c. */ @@ -69,29 +70,7 @@ ip6table_filter_hook(unsigned int hook, struct sk_buff *skb, return ip6t_do_table(skb, hook, in, out, net->ipv6.ip6table_filter); } -static struct nf_hook_ops ip6t_ops[] __read_mostly = { - { - .hook = ip6table_filter_hook, - .owner = THIS_MODULE, - .pf = NFPROTO_IPV6, - .hooknum = NF_INET_LOCAL_IN, - .priority = NF_IP6_PRI_FILTER, - }, - { - .hook = ip6table_filter_hook, - .owner = THIS_MODULE, - .pf = NFPROTO_IPV6, - .hooknum = NF_INET_FORWARD, - .priority = NF_IP6_PRI_FILTER, - }, - { - .hook = ip6table_filter_hook, - .owner = THIS_MODULE, - .pf = NFPROTO_IPV6, - .hooknum = NF_INET_LOCAL_OUT, - .priority = NF_IP6_PRI_FILTER, - }, -}; +static struct nf_hook_ops *filter_ops __read_mostly; /* Default to forward because I got too much mail already. */ static int forward = NF_ACCEPT; @@ -134,9 +113,11 @@ static int __init ip6table_filter_init(void) return ret; /* Register hooks */ - ret = nf_register_hooks(ip6t_ops, ARRAY_SIZE(ip6t_ops)); - if (ret < 0) + filter_ops = xt_hook_link(&packet_filter, ip6table_filter_hook); + if (IS_ERR(filter_ops)) { + ret = PTR_ERR(filter_ops); goto cleanup_table; + } return ret; @@ -147,7 +128,7 @@ static int __init ip6table_filter_init(void) static void __exit ip6table_filter_fini(void) { - nf_unregister_hooks(ip6t_ops, ARRAY_SIZE(ip6t_ops)); + xt_hook_unlink(&packet_filter, filter_ops); unregister_pernet_subsys(&ip6table_filter_net_ops); } diff --git a/net/ipv6/netfilter/ip6table_mangle.c b/net/ipv6/netfilter/ip6table_mangle.c index 405ac1f..5023ac5 100644 --- a/net/ipv6/netfilter/ip6table_mangle.c +++ b/net/ipv6/netfilter/ip6table_mangle.c @@ -62,6 +62,7 @@ static const struct xt_table packet_mangler = { .valid_hooks = MANGLE_VALID_HOOKS, .me = THIS_MODULE, .af = NFPROTO_IPV6, + .priority = NF_IP6_PRI_MANGLE, }; static unsigned int @@ -122,44 +123,7 @@ ip6table_mangle_hook(unsigned int hook, struct sk_buff *skb, dev_net(in)->ipv6.ip6table_mangle); } -static struct nf_hook_ops ip6t_ops[] __read_mostly = { - { - .hook = ip6table_mangle_hook, - .owner = THIS_MODULE, - .pf = NFPROTO_IPV6, - .hooknum = NF_INET_PRE_ROUTING, - .priority = NF_IP6_PRI_MANGLE, - }, - { - .hook = ip6table_mangle_hook, - .owner = THIS_MODULE, - .pf = NFPROTO_IPV6, - .hooknum = NF_INET_LOCAL_IN, - .priority = NF_IP6_PRI_MANGLE, - }, - { - .hook = ip6table_mangle_hook, - .owner = THIS_MODULE, - .pf = NFPROTO_IPV6, - .hooknum = NF_INET_FORWARD, - .priority = NF_IP6_PRI_MANGLE, - }, - { - .hook = ip6table_mangle_hook, - .owner = THIS_MODULE, - .pf = NFPROTO_IPV6, - .hooknum = NF_INET_LOCAL_OUT, - .priority = NF_IP6_PRI_MANGLE, - }, - { - .hook = ip6table_mangle_hook, - .owner = THIS_MODULE, - .pf = NFPROTO_IPV6, - .hooknum = NF_INET_POST_ROUTING, - .priority = NF_IP6_PRI_MANGLE, - }, -}; - +static struct nf_hook_ops *mangle_ops __read_mostly; static int __net_init ip6table_mangle_net_init(struct net *net) { /* Register table */ @@ -189,9 +153,11 @@ static int __init ip6table_mangle_init(void) return ret; /* Register hooks */ - ret = nf_register_hooks(ip6t_ops, ARRAY_SIZE(ip6t_ops)); - if (ret < 0) + mangle_ops = xt_hook_link(&packet_mangler, ip6table_mangle_hook); + if (IS_ERR(mangle_ops)) { + ret = PTR_ERR(mangle_ops); goto cleanup_table; + } return ret; @@ -202,7 +168,7 @@ static int __init ip6table_mangle_init(void) static void __exit ip6table_mangle_fini(void) { - nf_unregister_hooks(ip6t_ops, ARRAY_SIZE(ip6t_ops)); + xt_hook_unlink(&packet_mangler, mangle_ops); unregister_pernet_subsys(&ip6table_mangle_net_ops); } diff --git a/net/ipv6/netfilter/ip6table_raw.c b/net/ipv6/netfilter/ip6table_raw.c index 5451a36..3bfa695 100644 --- a/net/ipv6/netfilter/ip6table_raw.c +++ b/net/ipv6/netfilter/ip6table_raw.c @@ -40,6 +40,7 @@ static const struct xt_table packet_raw = { .valid_hooks = RAW_VALID_HOOKS, .me = THIS_MODULE, .af = NFPROTO_IPV6, + .priority = NF_IP6_PRI_FIRST, }; /* The work comes in here from netfilter.c. */ @@ -53,22 +54,7 @@ ip6table_raw_hook(unsigned int hook, struct sk_buff *skb, return ip6t_do_table(skb, hook, in, out, net->ipv6.ip6table_raw); } -static struct nf_hook_ops ip6t_ops[] __read_mostly = { - { - .hook = ip6table_raw_hook, - .pf = NFPROTO_IPV6, - .hooknum = NF_INET_PRE_ROUTING, - .priority = NF_IP6_PRI_FIRST, - .owner = THIS_MODULE, - }, - { - .hook = ip6table_raw_hook, - .pf = NFPROTO_IPV6, - .hooknum = NF_INET_LOCAL_OUT, - .priority = NF_IP6_PRI_FIRST, - .owner = THIS_MODULE, - }, -}; +static struct nf_hook_ops *rawtable_ops __read_mostly; static int __net_init ip6table_raw_net_init(struct net *net) { @@ -99,9 +85,11 @@ static int __init ip6table_raw_init(void) return ret; /* Register hooks */ - ret = nf_register_hooks(ip6t_ops, ARRAY_SIZE(ip6t_ops)); - if (ret < 0) + rawtable_ops = xt_hook_link(&packet_raw, ip6table_raw_hook); + if (IS_ERR(rawtable_ops)) { + ret = PTR_ERR(rawtable_ops); goto cleanup_table; + } return ret; @@ -112,7 +100,7 @@ static int __init ip6table_raw_init(void) static void __exit ip6table_raw_fini(void) { - nf_unregister_hooks(ip6t_ops, ARRAY_SIZE(ip6t_ops)); + xt_hook_unlink(&packet_raw, rawtable_ops); unregister_pernet_subsys(&ip6table_raw_net_ops); } diff --git a/net/ipv6/netfilter/ip6table_security.c b/net/ipv6/netfilter/ip6table_security.c index 841ea77..dd2200f 100644 --- a/net/ipv6/netfilter/ip6table_security.c +++ b/net/ipv6/netfilter/ip6table_security.c @@ -61,6 +61,7 @@ static const struct xt_table security_table = { .valid_hooks = SECURITY_VALID_HOOKS, .me = THIS_MODULE, .af = NFPROTO_IPV6, + .priority = NF_IP6_PRI_SECURITY, }; static unsigned int @@ -74,29 +75,7 @@ ip6table_security_hook(unsigned int hook, struct sk_buff *skb, return ip6t_do_table(skb, hook, in, out, net->ipv6.ip6table_security); } -static struct nf_hook_ops ip6t_ops[] __read_mostly = { - { - .hook = ip6table_security_hook, - .owner = THIS_MODULE, - .pf = NFPROTO_IPV6, - .hooknum = NF_INET_LOCAL_IN, - .priority = NF_IP6_PRI_SECURITY, - }, - { - .hook = ip6table_security_hook, - .owner = THIS_MODULE, - .pf = NFPROTO_IPV6, - .hooknum = NF_INET_FORWARD, - .priority = NF_IP6_PRI_SECURITY, - }, - { - .hook = ip6table_security_hook, - .owner = THIS_MODULE, - .pf = NFPROTO_IPV6, - .hooknum = NF_INET_LOCAL_OUT, - .priority = NF_IP6_PRI_SECURITY, - }, -}; +static struct nf_hook_ops *sectbl_ops __read_mostly; static int __net_init ip6table_security_net_init(struct net *net) { @@ -127,9 +106,11 @@ static int __init ip6table_security_init(void) if (ret < 0) return ret; - ret = nf_register_hooks(ip6t_ops, ARRAY_SIZE(ip6t_ops)); - if (ret < 0) + sectbl_ops = xt_hook_link(&security_table, ip6table_security_hook); + if (IS_ERR(sectbl_ops)) { + ret = PTR_ERR(sectbl_ops); goto cleanup_table; + } return ret; @@ -140,7 +121,7 @@ cleanup_table: static void __exit ip6table_security_fini(void) { - nf_unregister_hooks(ip6t_ops, ARRAY_SIZE(ip6t_ops)); + xt_hook_unlink(&security_table, sectbl_ops); unregister_pernet_subsys(&ip6table_security_net_ops); } diff --git a/net/netfilter/x_tables.c b/net/netfilter/x_tables.c index f01955c..b51cb0d 100644 --- a/net/netfilter/x_tables.c +++ b/net/netfilter/x_tables.c @@ -1091,6 +1091,60 @@ static const struct file_operations xt_target_ops = { #endif /* CONFIG_PROC_FS */ +/** + * xt_hook_link - set up hooks for a new table + * @table: table with metadata needed to set up hooks + * @fn: Hook function + * + * This function will take care of creating and registering the necessary + * Netfilter hooks for XT tables. + */ +struct nf_hook_ops *xt_hook_link(const struct xt_table *table, nf_hookfn *fn) +{ + unsigned int hook_mask = table->valid_hooks; + uint8_t i, num_hooks = hweight32(hook_mask); + uint8_t hooknum; + struct nf_hook_ops *ops; + int ret; + + ops = kmalloc(sizeof(*ops) * num_hooks, GFP_KERNEL); + if (ops == NULL) + return ERR_PTR(-ENOMEM); + + for (i = 0, hooknum = 0; i < num_hooks && hook_mask != 0; + hook_mask >>= 1, ++hooknum) { + if (!(hook_mask & 1)) + continue; + ops[i].hook = fn; + ops[i].owner = table->me; + ops[i].pf = table->af; + ops[i].hooknum = hooknum; + ops[i].priority = table->priority; + ++i; + } + + ret = nf_register_hooks(ops, num_hooks); + if (ret < 0) { + kfree(ops); + return ERR_PTR(ret); + } + + return ops; +} +EXPORT_SYMBOL_GPL(xt_hook_link); + +/** + * xt_hook_unlink - remove hooks for a table + * @ops: nf_hook_ops array as returned by nf_hook_link + * @hook_mask: the very same mask that was passed to nf_hook_link + */ +void xt_hook_unlink(const struct xt_table *table, struct nf_hook_ops *ops) +{ + nf_unregister_hooks(ops, hweight32(table->valid_hooks)); + kfree(ops); +} +EXPORT_SYMBOL_GPL(xt_hook_unlink); + int xt_proto_init(struct net *net, u_int8_t af) { #ifdef CONFIG_PROC_FS -- 2.7.4