netfilter: nf_ct_helper: implement variable length helper private data

This patch uses the new variable length conntrack extensions. Instead of using union nf_conntrack_help that contain all the helper private data information, we allocate variable length area to store the private helper data. This patch includes the modification of all existing helpers. It also includes a couple of include header to avoid compilation warnings. Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
mariux64 · Jun 16, 2012 · 1afc567 · 1afc567
1 parent 3cf4c7e
commit 1afc567
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Showing 17 changed files with 111 additions and 106 deletions.
diff --git a/include/linux/netfilter/nf_conntrack_sip.h b/include/linux/netfilter/nf_conntrack_sip.h
@@ -2,6 +2,8 @@
 #define __NF_CONNTRACK_SIP_H__
 #ifdef __KERNEL__
 
+#include <net/netfilter/nf_conntrack_expect.h>
+
 #define SIP_PORT	5060
 #define SIP_TIMEOUT	3600
 

diff --git a/include/net/netfilter/nf_conntrack.h b/include/net/netfilter/nf_conntrack.h
@@ -39,36 +39,6 @@ union nf_conntrack_expect_proto {
 	/* insert expect proto private data here */
 };
 
-/* Add protocol helper include file here */
-#include <linux/netfilter/nf_conntrack_ftp.h>
-#include <linux/netfilter/nf_conntrack_pptp.h>
-#include <linux/netfilter/nf_conntrack_h323.h>
-#include <linux/netfilter/nf_conntrack_sane.h>
-#include <linux/netfilter/nf_conntrack_sip.h>
-
-/* per conntrack: application helper private data */
-union nf_conntrack_help {
-	/* insert conntrack helper private data (master) here */
-#if defined(CONFIG_NF_CONNTRACK_FTP) || defined(CONFIG_NF_CONNTRACK_FTP_MODULE)
-	struct nf_ct_ftp_master ct_ftp_info;
-#endif
-#if defined(CONFIG_NF_CONNTRACK_PPTP) || \
-    defined(CONFIG_NF_CONNTRACK_PPTP_MODULE)
-	struct nf_ct_pptp_master ct_pptp_info;
-#endif
-#if defined(CONFIG_NF_CONNTRACK_H323) || \
-    defined(CONFIG_NF_CONNTRACK_H323_MODULE)
-	struct nf_ct_h323_master ct_h323_info;
-#endif
-#if defined(CONFIG_NF_CONNTRACK_SANE) || \
-    defined(CONFIG_NF_CONNTRACK_SANE_MODULE)
-	struct nf_ct_sane_master ct_sane_info;
-#endif
-#if defined(CONFIG_NF_CONNTRACK_SIP) || defined(CONFIG_NF_CONNTRACK_SIP_MODULE)
-	struct nf_ct_sip_master ct_sip_info;
-#endif
-};
-
 #include <linux/types.h>
 #include <linux/skbuff.h>
 #include <linux/timer.h>
@@ -89,12 +59,13 @@ struct nf_conn_help {
 	/* Helper. if any */
 	struct nf_conntrack_helper __rcu *helper;
 
-	union nf_conntrack_help help;
-
 	struct hlist_head expectations;
 
 	/* Current number of expected connections */
 	u8 expecting[NF_CT_MAX_EXPECT_CLASSES];
+
+	/* private helper information. */
+	char data[];
 };
 
 #include <net/netfilter/ipv4/nf_conntrack_ipv4.h>

diff --git a/include/net/netfilter/nf_conntrack_helper.h b/include/net/netfilter/nf_conntrack_helper.h
@@ -11,6 +11,7 @@
 #define _NF_CONNTRACK_HELPER_H
 #include <net/netfilter/nf_conntrack.h>
 #include <net/netfilter/nf_conntrack_extend.h>
+#include <net/netfilter/nf_conntrack_expect.h>
 
 struct module;
 
@@ -23,6 +24,9 @@ struct nf_conntrack_helper {
 	struct module *me;		/* pointer to self */
 	const struct nf_conntrack_expect_policy *expect_policy;
 
+	/* length of internal data, ie. sizeof(struct nf_ct_*_master) */
+	size_t data_len;
+
 	/* Tuple of things we will help (compared against server response) */
 	struct nf_conntrack_tuple tuple;
 
@@ -48,7 +52,7 @@ nf_conntrack_helper_try_module_get(const char *name, u16 l3num, u8 protonum);
 extern int nf_conntrack_helper_register(struct nf_conntrack_helper *);
 extern void nf_conntrack_helper_unregister(struct nf_conntrack_helper *);
 
-extern struct nf_conn_help *nf_ct_helper_ext_add(struct nf_conn *ct, gfp_t gfp);
+extern struct nf_conn_help *nf_ct_helper_ext_add(struct nf_conn *ct, struct nf_conntrack_helper *helper, gfp_t gfp);
 
 extern int __nf_ct_try_assign_helper(struct nf_conn *ct, struct nf_conn *tmpl,
 				     gfp_t flags);
@@ -60,6 +64,15 @@ static inline struct nf_conn_help *nfct_help(const struct nf_conn *ct)
 	return nf_ct_ext_find(ct, NF_CT_EXT_HELPER);
 }
 
+static inline void *nfct_help_data(const struct nf_conn *ct)
+{
+	struct nf_conn_help *help;
+
+	help = nf_ct_ext_find(ct, NF_CT_EXT_HELPER);
+
+	return (void *)help->data;
+}
+
 extern int nf_conntrack_helper_init(struct net *net);
 extern void nf_conntrack_helper_fini(struct net *net);
 

diff --git a/net/ipv4/netfilter/nf_nat_amanda.c b/net/ipv4/netfilter/nf_nat_amanda.c
@@ -13,10 +13,10 @@
 #include <linux/skbuff.h>
 #include <linux/udp.h>
 
-#include <net/netfilter/nf_nat_helper.h>
-#include <net/netfilter/nf_nat_rule.h>
 #include <net/netfilter/nf_conntrack_helper.h>
 #include <net/netfilter/nf_conntrack_expect.h>
+#include <net/netfilter/nf_nat_helper.h>
+#include <net/netfilter/nf_nat_rule.h>
 #include <linux/netfilter/nf_conntrack_amanda.h>
 
 MODULE_AUTHOR("Brian J. Murrell <netfilter@interlinx.bc.ca>");

diff --git a/net/ipv4/netfilter/nf_nat_h323.c b/net/ipv4/netfilter/nf_nat_h323.c
@@ -95,7 +95,7 @@ static int set_sig_addr(struct sk_buff *skb, struct nf_conn *ct,
 			unsigned char **data,
 			TransportAddress *taddr, int count)
 {
-	const struct nf_ct_h323_master *info = &nfct_help(ct)->help.ct_h323_info;
+	const struct nf_ct_h323_master *info = nfct_help_data(ct);
 	int dir = CTINFO2DIR(ctinfo);
 	int i;
 	__be16 port;
@@ -178,7 +178,7 @@ static int nat_rtp_rtcp(struct sk_buff *skb, struct nf_conn *ct,
 			struct nf_conntrack_expect *rtp_exp,
 			struct nf_conntrack_expect *rtcp_exp)
 {
-	struct nf_ct_h323_master *info = &nfct_help(ct)->help.ct_h323_info;
+	struct nf_ct_h323_master *info = nfct_help_data(ct);
 	int dir = CTINFO2DIR(ctinfo);
 	int i;
 	u_int16_t nated_port;
@@ -330,7 +330,7 @@ static int nat_h245(struct sk_buff *skb, struct nf_conn *ct,
 		    TransportAddress *taddr, __be16 port,
 		    struct nf_conntrack_expect *exp)
 {
-	struct nf_ct_h323_master *info = &nfct_help(ct)->help.ct_h323_info;
+	struct nf_ct_h323_master *info = nfct_help_data(ct);
 	int dir = CTINFO2DIR(ctinfo);
 	u_int16_t nated_port = ntohs(port);
 
@@ -419,7 +419,7 @@ static int nat_q931(struct sk_buff *skb, struct nf_conn *ct,
 		    unsigned char **data, TransportAddress *taddr, int idx,
 		    __be16 port, struct nf_conntrack_expect *exp)
 {
-	struct nf_ct_h323_master *info = &nfct_help(ct)->help.ct_h323_info;
+	struct nf_ct_h323_master *info = nfct_help_data(ct);
 	int dir = CTINFO2DIR(ctinfo);
 	u_int16_t nated_port = ntohs(port);
 	union nf_inet_addr addr;

diff --git a/net/ipv4/netfilter/nf_nat_pptp.c b/net/ipv4/netfilter/nf_nat_pptp.c
@@ -49,7 +49,7 @@ static void pptp_nat_expected(struct nf_conn *ct,
 	const struct nf_nat_pptp *nat_pptp_info;
 	struct nf_nat_ipv4_range range;
 
-	ct_pptp_info = &nfct_help(master)->help.ct_pptp_info;
+	ct_pptp_info = nfct_help_data(master);
 	nat_pptp_info = &nfct_nat(master)->help.nat_pptp_info;
 
 	/* And here goes the grand finale of corrosion... */
@@ -123,7 +123,7 @@ pptp_outbound_pkt(struct sk_buff *skb,
 	__be16 new_callid;
 	unsigned int cid_off;
 
-	ct_pptp_info  = &nfct_help(ct)->help.ct_pptp_info;
+	ct_pptp_info = nfct_help_data(ct);
 	nat_pptp_info = &nfct_nat(ct)->help.nat_pptp_info;
 
 	new_callid = ct_pptp_info->pns_call_id;
@@ -192,7 +192,7 @@ pptp_exp_gre(struct nf_conntrack_expect *expect_orig,
 	struct nf_ct_pptp_master *ct_pptp_info;
 	struct nf_nat_pptp *nat_pptp_info;
 
-	ct_pptp_info  = &nfct_help(ct)->help.ct_pptp_info;
+	ct_pptp_info = nfct_help_data(ct);
 	nat_pptp_info = &nfct_nat(ct)->help.nat_pptp_info;
 
 	/* save original PAC call ID in nat_info */

diff --git a/net/ipv4/netfilter/nf_nat_tftp.c b/net/ipv4/netfilter/nf_nat_tftp.c
@@ -8,10 +8,10 @@
 #include <linux/module.h>
 #include <linux/udp.h>
 
-#include <net/netfilter/nf_nat_helper.h>
-#include <net/netfilter/nf_nat_rule.h>
 #include <net/netfilter/nf_conntrack_helper.h>
 #include <net/netfilter/nf_conntrack_expect.h>
+#include <net/netfilter/nf_nat_helper.h>
+#include <net/netfilter/nf_nat_rule.h>
 #include <linux/netfilter/nf_conntrack_tftp.h>
 
 MODULE_AUTHOR("Magnus Boden <mb@ozaba.mine.nu>");

diff --git a/net/netfilter/nf_conntrack_core.c b/net/netfilter/nf_conntrack_core.c
@@ -819,7 +819,8 @@ init_conntrack(struct net *net, struct nf_conn *tmpl,
 		__set_bit(IPS_EXPECTED_BIT, &ct->status);
 		ct->master = exp->master;
 		if (exp->helper) {
-			help = nf_ct_helper_ext_add(ct, GFP_ATOMIC);
+			help = nf_ct_helper_ext_add(ct, exp->helper,
+						    GFP_ATOMIC);
 			if (help)
 				rcu_assign_pointer(help->helper, exp->helper);
 		}

diff --git a/net/netfilter/nf_conntrack_ftp.c b/net/netfilter/nf_conntrack_ftp.c
@@ -358,7 +358,7 @@ static int help(struct sk_buff *skb,
 	u32 seq;
 	int dir = CTINFO2DIR(ctinfo);
 	unsigned int uninitialized_var(matchlen), uninitialized_var(matchoff);
-	struct nf_ct_ftp_master *ct_ftp_info = &nfct_help(ct)->help.ct_ftp_info;
+	struct nf_ct_ftp_master *ct_ftp_info = nfct_help_data(ct);
 	struct nf_conntrack_expect *exp;
 	union nf_inet_addr *daddr;
 	struct nf_conntrack_man cmd = {};
@@ -554,6 +554,7 @@ static int __init nf_conntrack_ftp_init(void)
 		ftp[i][0].tuple.src.l3num = PF_INET;
 		ftp[i][1].tuple.src.l3num = PF_INET6;
 		for (j = 0; j < 2; j++) {
+			ftp[i][j].data_len = sizeof(struct nf_ct_ftp_master);
 			ftp[i][j].tuple.src.u.tcp.port = htons(ports[i]);
 			ftp[i][j].tuple.dst.protonum = IPPROTO_TCP;
 			ftp[i][j].expect_policy = &ftp_exp_policy;

diff --git a/net/netfilter/nf_conntrack_h323_main.c b/net/netfilter/nf_conntrack_h323_main.c
@@ -114,7 +114,7 @@ static int get_tpkt_data(struct sk_buff *skb, unsigned int protoff,
 			 struct nf_conn *ct, enum ip_conntrack_info ctinfo,
 			 unsigned char **data, int *datalen, int *dataoff)
 {
-	struct nf_ct_h323_master *info = &nfct_help(ct)->help.ct_h323_info;
+	struct nf_ct_h323_master *info = nfct_help_data(ct);
 	int dir = CTINFO2DIR(ctinfo);
 	const struct tcphdr *th;
 	struct tcphdr _tcph;
@@ -618,6 +618,7 @@ static const struct nf_conntrack_expect_policy h245_exp_policy = {
 static struct nf_conntrack_helper nf_conntrack_helper_h245 __read_mostly = {
 	.name			= "H.245",
 	.me			= THIS_MODULE,
+	.data_len		= sizeof(struct nf_ct_h323_master),
 	.tuple.src.l3num	= AF_UNSPEC,
 	.tuple.dst.protonum	= IPPROTO_UDP,
 	.help			= h245_help,
@@ -1170,6 +1171,7 @@ static struct nf_conntrack_helper nf_conntrack_helper_q931[] __read_mostly = {
 	{
 		.name			= "Q.931",
 		.me			= THIS_MODULE,
+		.data_len		= sizeof(struct nf_ct_h323_master),
 		.tuple.src.l3num	= AF_INET,
 		.tuple.src.u.tcp.port	= cpu_to_be16(Q931_PORT),
 		.tuple.dst.protonum	= IPPROTO_TCP,
@@ -1245,7 +1247,7 @@ static int expect_q931(struct sk_buff *skb, struct nf_conn *ct,
 		       unsigned char **data,
 		       TransportAddress *taddr, int count)
 {
-	struct nf_ct_h323_master *info = &nfct_help(ct)->help.ct_h323_info;
+	struct nf_ct_h323_master *info = nfct_help_data(ct);
 	int dir = CTINFO2DIR(ctinfo);
 	int ret = 0;
 	int i;
@@ -1360,7 +1362,7 @@ static int process_rrq(struct sk_buff *skb, struct nf_conn *ct,
 		       enum ip_conntrack_info ctinfo,
 		       unsigned char **data, RegistrationRequest *rrq)
 {
-	struct nf_ct_h323_master *info = &nfct_help(ct)->help.ct_h323_info;
+	struct nf_ct_h323_master *info = nfct_help_data(ct);
 	int ret;
 	typeof(set_ras_addr_hook) set_ras_addr;
 
@@ -1395,7 +1397,7 @@ static int process_rcf(struct sk_buff *skb, struct nf_conn *ct,
 		       enum ip_conntrack_info ctinfo,
 		       unsigned char **data, RegistrationConfirm *rcf)
 {
-	struct nf_ct_h323_master *info = &nfct_help(ct)->help.ct_h323_info;
+	struct nf_ct_h323_master *info = nfct_help_data(ct);
 	int dir = CTINFO2DIR(ctinfo);
 	int ret;
 	struct nf_conntrack_expect *exp;
@@ -1444,7 +1446,7 @@ static int process_urq(struct sk_buff *skb, struct nf_conn *ct,
 		       enum ip_conntrack_info ctinfo,
 		       unsigned char **data, UnregistrationRequest *urq)
 {
-	struct nf_ct_h323_master *info = &nfct_help(ct)->help.ct_h323_info;
+	struct nf_ct_h323_master *info = nfct_help_data(ct);
 	int dir = CTINFO2DIR(ctinfo);
 	int ret;
 	typeof(set_sig_addr_hook) set_sig_addr;
@@ -1476,7 +1478,7 @@ static int process_arq(struct sk_buff *skb, struct nf_conn *ct,
 		       enum ip_conntrack_info ctinfo,
 		       unsigned char **data, AdmissionRequest *arq)
 {
-	const struct nf_ct_h323_master *info = &nfct_help(ct)->help.ct_h323_info;
+	const struct nf_ct_h323_master *info = nfct_help_data(ct);
 	int dir = CTINFO2DIR(ctinfo);
 	__be16 port;
 	union nf_inet_addr addr;
@@ -1743,6 +1745,7 @@ static struct nf_conntrack_helper nf_conntrack_helper_ras[] __read_mostly = {
 	{
 		.name			= "RAS",
 		.me			= THIS_MODULE,
+		.data_len		= sizeof(struct nf_ct_h323_master),
 		.tuple.src.l3num	= AF_INET,
 		.tuple.src.u.udp.port	= cpu_to_be16(RAS_PORT),
 		.tuple.dst.protonum	= IPPROTO_UDP,
@@ -1752,6 +1755,7 @@ static struct nf_conntrack_helper nf_conntrack_helper_ras[] __read_mostly = {
 	{
 		.name			= "RAS",
 		.me			= THIS_MODULE,
+		.data_len		= sizeof(struct nf_ct_h323_master),
 		.tuple.src.l3num	= AF_INET6,
 		.tuple.src.u.udp.port	= cpu_to_be16(RAS_PORT),
 		.tuple.dst.protonum	= IPPROTO_UDP,

diff --git a/net/netfilter/nf_conntrack_helper.c b/net/netfilter/nf_conntrack_helper.c
@@ -161,11 +161,14 @@ nf_conntrack_helper_try_module_get(const char *name, u16 l3num, u8 protonum)
 }
 EXPORT_SYMBOL_GPL(nf_conntrack_helper_try_module_get);
 
-struct nf_conn_help *nf_ct_helper_ext_add(struct nf_conn *ct, gfp_t gfp)
+struct nf_conn_help *
+nf_ct_helper_ext_add(struct nf_conn *ct,
+		     struct nf_conntrack_helper *helper, gfp_t gfp)
 {
 	struct nf_conn_help *help;
 
-	help = nf_ct_ext_add(ct, NF_CT_EXT_HELPER, gfp);
+	help = nf_ct_ext_add_length(ct, NF_CT_EXT_HELPER,
+				    helper->data_len, gfp);
 	if (help)
 		INIT_HLIST_HEAD(&help->expectations);
 	else
@@ -218,13 +221,13 @@ int __nf_ct_try_assign_helper(struct nf_conn *ct, struct nf_conn *tmpl,
 	}
 
 	if (help == NULL) {
-		help = nf_ct_helper_ext_add(ct, flags);
+		help = nf_ct_helper_ext_add(ct, helper, flags);
 		if (help == NULL) {
 			ret = -ENOMEM;
 			goto out;
 		}
 	} else {
-		memset(&help->help, 0, sizeof(help->help));
+		memset(help->data, 0, helper->data_len);
 	}
 
 	rcu_assign_pointer(help->helper, helper);

diff --git a/net/netfilter/nf_conntrack_netlink.c b/net/netfilter/nf_conntrack_netlink.c
@@ -1218,7 +1218,7 @@ ctnetlink_change_helper(struct nf_conn *ct, const struct nlattr * const cda[])
 		if (help->helper)
 			return -EBUSY;
 		/* need to zero data of old helper */
-		memset(&help->help, 0, sizeof(help->help));
+		memset(help->data, 0, help->helper->data_len);
 	} else {
 		/* we cannot set a helper for an existing conntrack */
 		return -EOPNOTSUPP;
@@ -1440,7 +1440,7 @@ ctnetlink_create_conntrack(struct net *net, u16 zone,
 		} else {
 			struct nf_conn_help *help;
 
-			help = nf_ct_helper_ext_add(ct, GFP_ATOMIC);
+			help = nf_ct_helper_ext_add(ct, helper, GFP_ATOMIC);
 			if (help == NULL) {
 				err = -ENOMEM;
 				goto err2;