| /* L3/L4 protocol support for nf_conntrack. */ |
| |
| /* (C) 1999-2001 Paul `Rusty' Russell |
| * (C) 2002-2006 Netfilter Core Team <coreteam@netfilter.org> |
| * (C) 2003,2004 USAGI/WIDE Project <http://www.linux-ipv6.org> |
| * |
| * This program is free software; you can redistribute it and/or modify |
| * it under the terms of the GNU General Public License version 2 as |
| * published by the Free Software Foundation. |
| */ |
| |
| #include <linux/types.h> |
| #include <linux/netfilter.h> |
| #include <linux/module.h> |
| #include <linux/skbuff.h> |
| #include <linux/vmalloc.h> |
| #include <linux/stddef.h> |
| #include <linux/err.h> |
| #include <linux/percpu.h> |
| #include <linux/moduleparam.h> |
| #include <linux/notifier.h> |
| #include <linux/kernel.h> |
| #include <linux/netdevice.h> |
| |
| #include <net/netfilter/nf_conntrack.h> |
| #include <net/netfilter/nf_conntrack_l3proto.h> |
| #include <net/netfilter/nf_conntrack_l4proto.h> |
| #include <net/netfilter/nf_conntrack_core.h> |
| |
| struct nf_conntrack_l4proto **nf_ct_protos[PF_MAX] __read_mostly; |
| struct nf_conntrack_l3proto *nf_ct_l3protos[PF_MAX] __read_mostly; |
| |
| struct nf_conntrack_l4proto * |
| __nf_ct_l4proto_find(u_int16_t l3proto, u_int8_t l4proto) |
| { |
| if (unlikely(l3proto >= AF_MAX || nf_ct_protos[l3proto] == NULL)) |
| return &nf_conntrack_l4proto_generic; |
| |
| return nf_ct_protos[l3proto][l4proto]; |
| } |
| |
| /* this is guaranteed to always return a valid protocol helper, since |
| * it falls back to generic_protocol */ |
| struct nf_conntrack_l4proto * |
| nf_ct_l4proto_find_get(u_int16_t l3proto, u_int8_t l4proto) |
| { |
| struct nf_conntrack_l4proto *p; |
| |
| preempt_disable(); |
| p = __nf_ct_l4proto_find(l3proto, l4proto); |
| if (!try_module_get(p->me)) |
| p = &nf_conntrack_l4proto_generic; |
| preempt_enable(); |
| |
| return p; |
| } |
| |
| void nf_ct_l4proto_put(struct nf_conntrack_l4proto *p) |
| { |
| module_put(p->me); |
| } |
| |
| struct nf_conntrack_l3proto * |
| nf_ct_l3proto_find_get(u_int16_t l3proto) |
| { |
| struct nf_conntrack_l3proto *p; |
| |
| preempt_disable(); |
| p = __nf_ct_l3proto_find(l3proto); |
| if (!try_module_get(p->me)) |
| p = &nf_conntrack_l3proto_generic; |
| preempt_enable(); |
| |
| return p; |
| } |
| |
| void nf_ct_l3proto_put(struct nf_conntrack_l3proto *p) |
| { |
| module_put(p->me); |
| } |
| |
| int |
| nf_ct_l3proto_try_module_get(unsigned short l3proto) |
| { |
| int ret; |
| struct nf_conntrack_l3proto *p; |
| |
| retry: p = nf_ct_l3proto_find_get(l3proto); |
| if (p == &nf_conntrack_l3proto_generic) { |
| ret = request_module("nf_conntrack-%d", l3proto); |
| if (!ret) |
| goto retry; |
| |
| return -EPROTOTYPE; |
| } |
| |
| return 0; |
| } |
| |
| void nf_ct_l3proto_module_put(unsigned short l3proto) |
| { |
| struct nf_conntrack_l3proto *p; |
| |
| preempt_disable(); |
| p = __nf_ct_l3proto_find(l3proto); |
| preempt_enable(); |
| |
| module_put(p->me); |
| } |
| |
| static int kill_l3proto(struct nf_conn *i, void *data) |
| { |
| return (i->tuplehash[IP_CT_DIR_ORIGINAL].tuple.src.l3num == |
| ((struct nf_conntrack_l3proto *)data)->l3proto); |
| } |
| |
| static int kill_l4proto(struct nf_conn *i, void *data) |
| { |
| struct nf_conntrack_l4proto *l4proto; |
| l4proto = (struct nf_conntrack_l4proto *)data; |
| return (i->tuplehash[IP_CT_DIR_ORIGINAL].tuple.dst.protonum == |
| l4proto->l4proto) && |
| (i->tuplehash[IP_CT_DIR_ORIGINAL].tuple.src.l3num == |
| l4proto->l3proto); |
| } |
| |
| int nf_conntrack_l3proto_register(struct nf_conntrack_l3proto *proto) |
| { |
| int ret = 0; |
| |
| write_lock_bh(&nf_conntrack_lock); |
| if (nf_ct_l3protos[proto->l3proto] != &nf_conntrack_l3proto_generic) { |
| ret = -EBUSY; |
| goto out; |
| } |
| nf_ct_l3protos[proto->l3proto] = proto; |
| out: |
| write_unlock_bh(&nf_conntrack_lock); |
| |
| return ret; |
| } |
| |
| void nf_conntrack_l3proto_unregister(struct nf_conntrack_l3proto *proto) |
| { |
| write_lock_bh(&nf_conntrack_lock); |
| nf_ct_l3protos[proto->l3proto] = &nf_conntrack_l3proto_generic; |
| write_unlock_bh(&nf_conntrack_lock); |
| |
| /* Somebody could be still looking at the proto in bh. */ |
| synchronize_net(); |
| |
| /* Remove all contrack entries for this protocol */ |
| nf_ct_iterate_cleanup(kill_l3proto, proto); |
| } |
| |
| /* FIXME: Allow NULL functions and sub in pointers to generic for |
| them. --RR */ |
| int nf_conntrack_l4proto_register(struct nf_conntrack_l4proto *l4proto) |
| { |
| int ret = 0; |
| |
| retry: |
| write_lock_bh(&nf_conntrack_lock); |
| if (nf_ct_protos[l4proto->l3proto]) { |
| if (nf_ct_protos[l4proto->l3proto][l4proto->l4proto] |
| != &nf_conntrack_l4proto_generic) { |
| ret = -EBUSY; |
| goto out_unlock; |
| } |
| } else { |
| /* l3proto may be loaded latter. */ |
| struct nf_conntrack_l4proto **proto_array; |
| int i; |
| |
| write_unlock_bh(&nf_conntrack_lock); |
| |
| proto_array = (struct nf_conntrack_l4proto **) |
| kmalloc(MAX_NF_CT_PROTO * |
| sizeof(struct nf_conntrack_l4proto *), |
| GFP_KERNEL); |
| if (proto_array == NULL) { |
| ret = -ENOMEM; |
| goto out; |
| } |
| for (i = 0; i < MAX_NF_CT_PROTO; i++) |
| proto_array[i] = &nf_conntrack_l4proto_generic; |
| |
| write_lock_bh(&nf_conntrack_lock); |
| if (nf_ct_protos[l4proto->l3proto]) { |
| /* bad timing, but no problem */ |
| write_unlock_bh(&nf_conntrack_lock); |
| kfree(proto_array); |
| } else { |
| nf_ct_protos[l4proto->l3proto] = proto_array; |
| write_unlock_bh(&nf_conntrack_lock); |
| } |
| |
| /* |
| * Just once because array is never freed until unloading |
| * nf_conntrack.ko |
| */ |
| goto retry; |
| } |
| |
| nf_ct_protos[l4proto->l3proto][l4proto->l4proto] = l4proto; |
| |
| out_unlock: |
| write_unlock_bh(&nf_conntrack_lock); |
| out: |
| return ret; |
| } |
| |
| void nf_conntrack_l4proto_unregister(struct nf_conntrack_l4proto *l4proto) |
| { |
| write_lock_bh(&nf_conntrack_lock); |
| nf_ct_protos[l4proto->l3proto][l4proto->l4proto] |
| = &nf_conntrack_l4proto_generic; |
| write_unlock_bh(&nf_conntrack_lock); |
| |
| /* Somebody could be still looking at the proto in bh. */ |
| synchronize_net(); |
| |
| /* Remove all contrack entries for this protocol */ |
| nf_ct_iterate_cleanup(kill_l4proto, l4proto); |
| } |