From 544d5c7d9f4d1ec4f170bc5bcc522012cb7704bc Mon Sep 17 00:00:00 2001 From: Pablo Neira Ayuso Date: Sun, 5 Feb 2012 03:44:51 +0100 Subject: [PATCH] netfilter: ctnetlink: allow to set expectfn for expectations This patch allows you to set expectfn which is specifically used by the NAT side of most of the existing conntrack helpers. I have added a symbol map that uses a string as key to look up for the function that is attached to the expectation object. This is the best solution I came out with to solve this issue. Signed-off-by: Pablo Neira Ayuso --- include/linux/netfilter/nfnetlink_conntrack.h | 1 + include/net/netfilter/nf_conntrack_helper.h | 13 +++++ net/ipv4/netfilter/nf_nat_core.c | 8 +++ net/ipv4/netfilter/nf_nat_h323.c | 14 +++++ net/ipv4/netfilter/nf_nat_sip.c | 7 +++ net/netfilter/nf_conntrack_helper.c | 54 +++++++++++++++++++ net/netfilter/nf_conntrack_netlink.c | 19 ++++++- 7 files changed, 115 insertions(+), 1 deletion(-) diff --git a/include/linux/netfilter/nfnetlink_conntrack.h b/include/linux/netfilter/nfnetlink_conntrack.h index a2f1f483ecc9..e58e4b93c108 100644 --- a/include/linux/netfilter/nfnetlink_conntrack.h +++ b/include/linux/netfilter/nfnetlink_conntrack.h @@ -175,6 +175,7 @@ enum ctattr_expect { CTA_EXPECT_FLAGS, CTA_EXPECT_CLASS, CTA_EXPECT_NAT, + CTA_EXPECT_FN, __CTA_EXPECT_MAX }; #define CTA_EXPECT_MAX (__CTA_EXPECT_MAX - 1) diff --git a/include/net/netfilter/nf_conntrack_helper.h b/include/net/netfilter/nf_conntrack_helper.h index f1c1311adc2c..5767dc242dee 100644 --- a/include/net/netfilter/nf_conntrack_helper.h +++ b/include/net/netfilter/nf_conntrack_helper.h @@ -69,4 +69,17 @@ extern int nf_conntrack_broadcast_help(struct sk_buff *skb, enum ip_conntrack_info ctinfo, unsigned int timeout); +struct nf_ct_helper_expectfn { + struct list_head head; + const char *name; + void (*expectfn)(struct nf_conn *ct, struct nf_conntrack_expect *exp); +}; + +void nf_ct_helper_expectfn_register(struct nf_ct_helper_expectfn *n); +void nf_ct_helper_expectfn_unregister(struct nf_ct_helper_expectfn *n); +struct nf_ct_helper_expectfn * +nf_ct_helper_expectfn_find_by_name(const char *name); +struct nf_ct_helper_expectfn * +nf_ct_helper_expectfn_find_by_symbol(const void *symbol); + #endif /*_NF_CONNTRACK_HELPER_H*/ diff --git a/net/ipv4/netfilter/nf_nat_core.c b/net/ipv4/netfilter/nf_nat_core.c index a708933dc230..abb52adf5acd 100644 --- a/net/ipv4/netfilter/nf_nat_core.c +++ b/net/ipv4/netfilter/nf_nat_core.c @@ -686,6 +686,11 @@ static struct pernet_operations nf_nat_net_ops = { .exit = nf_nat_net_exit, }; +static struct nf_ct_helper_expectfn follow_master_nat = { + .name = "nat-follow-master", + .expectfn = nf_nat_follow_master, +}; + static int __init nf_nat_init(void) { size_t i; @@ -717,6 +722,8 @@ static int __init nf_nat_init(void) l3proto = nf_ct_l3proto_find_get((u_int16_t)AF_INET); + nf_ct_helper_expectfn_register(&follow_master_nat); + BUG_ON(nf_nat_seq_adjust_hook != NULL); RCU_INIT_POINTER(nf_nat_seq_adjust_hook, nf_nat_seq_adjust); BUG_ON(nfnetlink_parse_nat_setup_hook != NULL); @@ -736,6 +743,7 @@ static void __exit nf_nat_cleanup(void) unregister_pernet_subsys(&nf_nat_net_ops); nf_ct_l3proto_put(l3proto); nf_ct_extend_unregister(&nat_extend); + nf_ct_helper_expectfn_unregister(&follow_master_nat); RCU_INIT_POINTER(nf_nat_seq_adjust_hook, NULL); RCU_INIT_POINTER(nfnetlink_parse_nat_setup_hook, NULL); RCU_INIT_POINTER(nf_ct_nat_offset, NULL); diff --git a/net/ipv4/netfilter/nf_nat_h323.c b/net/ipv4/netfilter/nf_nat_h323.c index dc1dd912baf4..82536701e3a3 100644 --- a/net/ipv4/netfilter/nf_nat_h323.c +++ b/net/ipv4/netfilter/nf_nat_h323.c @@ -568,6 +568,16 @@ static int nat_callforwarding(struct sk_buff *skb, struct nf_conn *ct, return 0; } +static struct nf_ct_helper_expectfn q931_nat = { + .name = "Q.931", + .expectfn = ip_nat_q931_expect, +}; + +static struct nf_ct_helper_expectfn callforwarding_nat = { + .name = "callforwarding", + .expectfn = ip_nat_callforwarding_expect, +}; + /****************************************************************************/ static int __init init(void) { @@ -590,6 +600,8 @@ static int __init init(void) RCU_INIT_POINTER(nat_h245_hook, nat_h245); RCU_INIT_POINTER(nat_callforwarding_hook, nat_callforwarding); RCU_INIT_POINTER(nat_q931_hook, nat_q931); + nf_ct_helper_expectfn_register(&q931_nat); + nf_ct_helper_expectfn_register(&callforwarding_nat); return 0; } @@ -605,6 +617,8 @@ static void __exit fini(void) RCU_INIT_POINTER(nat_h245_hook, NULL); RCU_INIT_POINTER(nat_callforwarding_hook, NULL); RCU_INIT_POINTER(nat_q931_hook, NULL); + nf_ct_helper_expectfn_unregister(&q931_nat); + nf_ct_helper_expectfn_unregister(&callforwarding_nat); synchronize_rcu(); } diff --git a/net/ipv4/netfilter/nf_nat_sip.c b/net/ipv4/netfilter/nf_nat_sip.c index d0319f96269f..57932c43960e 100644 --- a/net/ipv4/netfilter/nf_nat_sip.c +++ b/net/ipv4/netfilter/nf_nat_sip.c @@ -526,6 +526,11 @@ err1: return NF_DROP; } +static struct nf_ct_helper_expectfn sip_nat = { + .name = "sip", + .expectfn = ip_nat_sip_expected, +}; + static void __exit nf_nat_sip_fini(void) { RCU_INIT_POINTER(nf_nat_sip_hook, NULL); @@ -535,6 +540,7 @@ static void __exit nf_nat_sip_fini(void) RCU_INIT_POINTER(nf_nat_sdp_port_hook, NULL); RCU_INIT_POINTER(nf_nat_sdp_session_hook, NULL); RCU_INIT_POINTER(nf_nat_sdp_media_hook, NULL); + nf_ct_helper_expectfn_unregister(&sip_nat); synchronize_rcu(); } @@ -554,6 +560,7 @@ static int __init nf_nat_sip_init(void) RCU_INIT_POINTER(nf_nat_sdp_port_hook, ip_nat_sdp_port); RCU_INIT_POINTER(nf_nat_sdp_session_hook, ip_nat_sdp_session); RCU_INIT_POINTER(nf_nat_sdp_media_hook, ip_nat_sdp_media); + nf_ct_helper_expectfn_register(&sip_nat); return 0; } diff --git a/net/netfilter/nf_conntrack_helper.c b/net/netfilter/nf_conntrack_helper.c index bbe23baa19b6..436b7cb79ba4 100644 --- a/net/netfilter/nf_conntrack_helper.c +++ b/net/netfilter/nf_conntrack_helper.c @@ -181,6 +181,60 @@ void nf_ct_helper_destroy(struct nf_conn *ct) } } +static LIST_HEAD(nf_ct_helper_expectfn_list); + +void nf_ct_helper_expectfn_register(struct nf_ct_helper_expectfn *n) +{ + spin_lock_bh(&nf_conntrack_lock); + list_add_rcu(&n->head, &nf_ct_helper_expectfn_list); + spin_unlock_bh(&nf_conntrack_lock); +} +EXPORT_SYMBOL_GPL(nf_ct_helper_expectfn_register); + +void nf_ct_helper_expectfn_unregister(struct nf_ct_helper_expectfn *n) +{ + spin_lock_bh(&nf_conntrack_lock); + list_del_rcu(&n->head); + spin_unlock_bh(&nf_conntrack_lock); +} +EXPORT_SYMBOL_GPL(nf_ct_helper_expectfn_unregister); + +struct nf_ct_helper_expectfn * +nf_ct_helper_expectfn_find_by_name(const char *name) +{ + struct nf_ct_helper_expectfn *cur; + bool found = false; + + rcu_read_lock(); + list_for_each_entry_rcu(cur, &nf_ct_helper_expectfn_list, head) { + if (!strcmp(cur->name, name)) { + found = true; + break; + } + } + rcu_read_unlock(); + return found ? cur : NULL; +} +EXPORT_SYMBOL_GPL(nf_ct_helper_expectfn_find_by_name); + +struct nf_ct_helper_expectfn * +nf_ct_helper_expectfn_find_by_symbol(const void *symbol) +{ + struct nf_ct_helper_expectfn *cur; + bool found = false; + + rcu_read_lock(); + list_for_each_entry_rcu(cur, &nf_ct_helper_expectfn_list, head) { + if (cur->expectfn == symbol) { + found = true; + break; + } + } + rcu_read_unlock(); + return found ? cur : NULL; +} +EXPORT_SYMBOL_GPL(nf_ct_helper_expectfn_find_by_symbol); + int nf_conntrack_helper_register(struct nf_conntrack_helper *me) { unsigned int h = helper_hash(&me->tuple); diff --git a/net/netfilter/nf_conntrack_netlink.c b/net/netfilter/nf_conntrack_netlink.c index 845c8ca28563..b8827e8a11fe 100644 --- a/net/netfilter/nf_conntrack_netlink.c +++ b/net/netfilter/nf_conntrack_netlink.c @@ -1679,6 +1679,8 @@ ctnetlink_exp_dump_expect(struct sk_buff *skb, struct nlattr *nest_parms; struct nf_conntrack_tuple nat_tuple = {}; #endif + struct nf_ct_helper_expectfn *expfn; + if (timeout < 0) timeout = 0; @@ -1722,6 +1724,9 @@ ctnetlink_exp_dump_expect(struct sk_buff *skb, if (helper) NLA_PUT_STRING(skb, CTA_EXPECT_HELP_NAME, helper->name); } + expfn = nf_ct_helper_expectfn_find_by_symbol(exp->expectfn); + if (expfn != NULL) + NLA_PUT_STRING(skb, CTA_EXPECT_FN, expfn->name); return 0; @@ -1881,6 +1886,7 @@ static const struct nla_policy exp_nla_policy[CTA_EXPECT_MAX+1] = { [CTA_EXPECT_FLAGS] = { .type = NLA_U32 }, [CTA_EXPECT_CLASS] = { .type = NLA_U32 }, [CTA_EXPECT_NAT] = { .type = NLA_NESTED }, + [CTA_EXPECT_FN] = { .type = NLA_NUL_STRING }, }; static int @@ -2182,9 +2188,20 @@ ctnetlink_create_expect(struct net *net, u16 zone, } else exp->flags = 0; } + if (cda[CTA_EXPECT_FN]) { + const char *name = nla_data(cda[CTA_EXPECT_FN]); + struct nf_ct_helper_expectfn *expfn; + + expfn = nf_ct_helper_expectfn_find_by_name(name); + if (expfn == NULL) { + err = -EINVAL; + goto err_out; + } + exp->expectfn = expfn->expectfn; + } else + exp->expectfn = NULL; exp->class = class; - exp->expectfn = NULL; exp->master = ct; exp->helper = helper; memcpy(&exp->tuple, &tuple, sizeof(struct nf_conntrack_tuple)); -- 2.20.1