From 8f03dea52b1d0227656319e1b0822628b43791a8 Mon Sep 17 00:00:00 2001 From: Martin Josefsson Date: Wed, 29 Nov 2006 02:35:03 +0100 Subject: [NETFILTER]: nf_conntrack: split out protocol handling This patch splits out L3/L4 protocol handling into its own file nf_conntrack_proto.c Signed-off-by: Martin Josefsson Signed-off-by: Patrick McHardy --- net/netfilter/nf_conntrack_proto.c | 225 +++++++++++++++++++++++++++++++++++++ 1 file changed, 225 insertions(+) create mode 100644 net/netfilter/nf_conntrack_proto.c (limited to 'net/netfilter/nf_conntrack_proto.c') diff --git a/net/netfilter/nf_conntrack_proto.c b/net/netfilter/nf_conntrack_proto.c new file mode 100644 index 000000000000..24c61a384716 --- /dev/null +++ b/net/netfilter/nf_conntrack_proto.c @@ -0,0 +1,225 @@ +/* L3/L4 protocol support for nf_conntrack. */ + +/* (C) 1999-2001 Paul `Rusty' Russell + * (C) 2002-2006 Netfilter Core Team + * (C) 2003,2004 USAGI/WIDE Project + * + * 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 +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#include +#include +#include +#include + +struct nf_conntrack_protocol **nf_ct_protos[PF_MAX] __read_mostly; +struct nf_conntrack_l3proto *nf_ct_l3protos[PF_MAX] __read_mostly; + +struct nf_conntrack_protocol * +__nf_ct_proto_find(u_int16_t l3proto, u_int8_t protocol) +{ + if (unlikely(l3proto >= AF_MAX || nf_ct_protos[l3proto] == NULL)) + return &nf_conntrack_generic_protocol; + + return nf_ct_protos[l3proto][protocol]; +} + +/* this is guaranteed to always return a valid protocol helper, since + * it falls back to generic_protocol */ +struct nf_conntrack_protocol * +nf_ct_proto_find_get(u_int16_t l3proto, u_int8_t protocol) +{ + struct nf_conntrack_protocol *p; + + preempt_disable(); + p = __nf_ct_proto_find(l3proto, protocol); + if (!try_module_get(p->me)) + p = &nf_conntrack_generic_protocol; + preempt_enable(); + + return p; +} + +void nf_ct_proto_put(struct nf_conntrack_protocol *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_generic_l3proto; + 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_generic_l3proto) { + 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_proto(struct nf_conn *i, void *data) +{ + struct nf_conntrack_protocol *proto; + proto = (struct nf_conntrack_protocol *)data; + return (i->tuplehash[IP_CT_DIR_ORIGINAL].tuple.dst.protonum == + proto->proto) && + (i->tuplehash[IP_CT_DIR_ORIGINAL].tuple.src.l3num == + proto->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_generic_l3proto) { + 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_generic_l3proto; + 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_protocol_register(struct nf_conntrack_protocol *proto) +{ + int ret = 0; + +retry: + write_lock_bh(&nf_conntrack_lock); + if (nf_ct_protos[proto->l3proto]) { + if (nf_ct_protos[proto->l3proto][proto->proto] + != &nf_conntrack_generic_protocol) { + ret = -EBUSY; + goto out_unlock; + } + } else { + /* l3proto may be loaded latter. */ + struct nf_conntrack_protocol **proto_array; + int i; + + write_unlock_bh(&nf_conntrack_lock); + + proto_array = (struct nf_conntrack_protocol **) + kmalloc(MAX_NF_CT_PROTO * + sizeof(struct nf_conntrack_protocol *), + GFP_KERNEL); + if (proto_array == NULL) { + ret = -ENOMEM; + goto out; + } + for (i = 0; i < MAX_NF_CT_PROTO; i++) + proto_array[i] = &nf_conntrack_generic_protocol; + + write_lock_bh(&nf_conntrack_lock); + if (nf_ct_protos[proto->l3proto]) { + /* bad timing, but no problem */ + write_unlock_bh(&nf_conntrack_lock); + kfree(proto_array); + } else { + nf_ct_protos[proto->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[proto->l3proto][proto->proto] = proto; + +out_unlock: + write_unlock_bh(&nf_conntrack_lock); +out: + return ret; +} + +void nf_conntrack_protocol_unregister(struct nf_conntrack_protocol *proto) +{ + write_lock_bh(&nf_conntrack_lock); + nf_ct_protos[proto->l3proto][proto->proto] + = &nf_conntrack_generic_protocol; + 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_proto, proto); +} -- cgit v1.2.3