netfilter: xtables: move extension arguments into compound structure (1/6)

The function signatures for Xtables extensions have grown over time.
It involves a lot of typing/replication, and also a bit of stack space
even if they are not used. Realize an NFWS2008 idea and pack them into
structs. The skb remains outside of the struct so gcc can continue to
apply its optimizations.

This patch does this for match extensions' match functions.

A few ambiguities have also been addressed. The "offset" parameter for
example has been renamed to "fragoff" (there are so many different
offsets already) and "protoff" to "thoff" (there is more than just one
protocol here, so clarify).

Signed-off-by: Jan Engelhardt <jengelh@medozas.de>
Signed-off-by: Patrick McHardy <kaber@trash.net>

9 files changed, 47 insertions, 81 deletions

diff --git a/net/ipv6/netfilter/ip6_tables.c b/net/ipv6/netfilter/ip6_tables.c
index 12c41b8..cf2c537 100644
--- a/net/ipv6/netfilter/ip6_tables.c
+++ b/net/ipv6/netfilter/ip6_tables.c
@@ -215,17 +215,14 @@ ip6t_error(struct sk_buff *skb,
 
 /* Performance critical - called for every packet */
 static inline bool
-do_match(struct ip6t_entry_match *m,
-	      const struct sk_buff *skb,
-	      const struct net_device *in,
-	      const struct net_device *out,
-	      int offset,
-	      unsigned int protoff,
-	      bool *hotdrop)
+do_match(struct ip6t_entry_match *m, const struct sk_buff *skb,
+	 struct xt_match_param *par)
 {
+	par->match     = m->u.kernel.match;
+	par->matchinfo = m->data;
+
 	/* Stop iteration if it doesn't match */
-	if (!m->u.kernel.match->match(skb, in, out, m->u.kernel.match, m->data,
-				      offset, protoff, hotdrop))
+	if (!m->u.kernel.match->match(skb, par))
 		return true;
 	else
 		return false;
@@ -355,8 +352,6 @@ ip6t_do_table(struct sk_buff *skb,
 	      struct xt_table *table)
 {
 	static const char nulldevname[IFNAMSIZ] __attribute__((aligned(sizeof(long))));
-	int offset = 0;
-	unsigned int protoff = 0;
 	bool hotdrop = false;
 	/* Initializing verdict to NF_DROP keeps gcc happy. */
 	unsigned int verdict = NF_DROP;
@@ -364,6 +359,7 @@ ip6t_do_table(struct sk_buff *skb,
 	void *table_base;
 	struct ip6t_entry *e, *back;
 	struct xt_table_info *private;
+	struct xt_match_param mtpar;
 
 	/* Initialization */
 	indev = in ? in->name : nulldevname;
@@ -374,6 +370,9 @@ ip6t_do_table(struct sk_buff *skb,
 	 * things we don't know, ie. tcp syn flag or ports).  If the
 	 * rule is also a fragment-specific rule, non-fragments won't
 	 * match it. */
+	mtpar.hotdrop = &hotdrop;
+	mtpar.in      = in;
+	mtpar.out     = out;
 
 	read_lock_bh(&table->lock);
 	IP_NF_ASSERT(table->valid_hooks & (1 << hook));
@@ -388,12 +387,10 @@ ip6t_do_table(struct sk_buff *skb,
 		IP_NF_ASSERT(e);
 		IP_NF_ASSERT(back);
 		if (ip6_packet_match(skb, indev, outdev, &e->ipv6,
-			&protoff, &offset, &hotdrop)) {
+			&mtpar.thoff, &mtpar.fragoff, &hotdrop)) {
 			struct ip6t_entry_target *t;
 
-			if (IP6T_MATCH_ITERATE(e, do_match,
-					       skb, in, out,
-					       offset, protoff, &hotdrop) != 0)
+			if (IP6T_MATCH_ITERATE(e, do_match, skb, &mtpar) != 0)
 				goto no_match;
 
 			ADD_COUNTER(e->counters,
@@ -2141,30 +2138,23 @@ icmp6_type_code_match(u_int8_t test_type, u_int8_t min_code, u_int8_t max_code,
 }
 
 static bool
-icmp6_match(const struct sk_buff *skb,
-	   const struct net_device *in,
-	   const struct net_device *out,
-	   const struct xt_match *match,
-	   const void *matchinfo,
-	   int offset,
-	   unsigned int protoff,
-	   bool *hotdrop)
+icmp6_match(const struct sk_buff *skb, const struct xt_match_param *par)
 {
 	const struct icmp6hdr *ic;
 	struct icmp6hdr _icmph;
-	const struct ip6t_icmp *icmpinfo = matchinfo;
+	const struct ip6t_icmp *icmpinfo = par->matchinfo;
 
 	/* Must not be a fragment. */
-	if (offset)
+	if (par->fragoff != 0)
 		return false;
 
-	ic = skb_header_pointer(skb, protoff, sizeof(_icmph), &_icmph);
+	ic = skb_header_pointer(skb, par->thoff, sizeof(_icmph), &_icmph);
 	if (ic == NULL) {
 		/* We've been asked to examine this packet, and we
 		 * can't.  Hence, no choice but to drop.
 		 */
 		duprintf("Dropping evil ICMP tinygram.\n");
-		*hotdrop = true;
+		*par->hotdrop = true;
 		return false;
 	}
 
diff --git a/net/ipv6/netfilter/ip6t_ah.c b/net/ipv6/netfilter/ip6t_ah.c
index 061f89b..a04f2b8 100644
--- a/net/ipv6/netfilter/ip6t_ah.c
+++ b/net/ipv6/netfilter/ip6t_ah.c
@@ -36,14 +36,11 @@ spi_match(u_int32_t min, u_int32_t max, u_int32_t spi, bool invert)
 	return r;
 }
 
-static bool
-ah_mt6(const struct sk_buff *skb, const struct net_device *in,
-       const struct net_device *out, const struct xt_match *match,
-       const void *matchinfo, int offset, unsigned int protoff, bool *hotdrop)
+static bool ah_mt6(const struct sk_buff *skb, const struct xt_match_param *par)
 {
 	struct ip_auth_hdr _ah;
 	const struct ip_auth_hdr *ah;
-	const struct ip6t_ah *ahinfo = matchinfo;
+	const struct ip6t_ah *ahinfo = par->matchinfo;
 	unsigned int ptr;
 	unsigned int hdrlen = 0;
 	int err;
@@ -51,13 +48,13 @@ ah_mt6(const struct sk_buff *skb, const struct net_device *in,
 	err = ipv6_find_hdr(skb, &ptr, NEXTHDR_AUTH, NULL);
 	if (err < 0) {
 		if (err != -ENOENT)
-			*hotdrop = true;
+			*par->hotdrop = true;
 		return false;
 	}
 
 	ah = skb_header_pointer(skb, ptr, sizeof(_ah), &_ah);
 	if (ah == NULL) {
-		*hotdrop = true;
+		*par->hotdrop = true;
 		return false;
 	}
 
diff --git a/net/ipv6/netfilter/ip6t_eui64.c b/net/ipv6/netfilter/ip6t_eui64.c
index ba38df1..db610ba 100644
--- a/net/ipv6/netfilter/ip6t_eui64.c
+++ b/net/ipv6/netfilter/ip6t_eui64.c
@@ -20,18 +20,15 @@ MODULE_LICENSE("GPL");
 MODULE_AUTHOR("Andras Kis-Szabo <kisza@sch.bme.hu>");
 
 static bool
-eui64_mt6(const struct sk_buff *skb, const struct net_device *in,
-          const struct net_device *out, const struct xt_match *match,
-          const void *matchinfo, int offset, unsigned int protoff,
-          bool *hotdrop)
+eui64_mt6(const struct sk_buff *skb, const struct xt_match_param *par)
 {
 	unsigned char eui64[8];
 	int i = 0;
 
 	if (!(skb_mac_header(skb) >= skb->head &&
 	      skb_mac_header(skb) + ETH_HLEN <= skb->data) &&
-	    offset != 0) {
-		*hotdrop = true;
+	    par->fragoff != 0) {
+		*par->hotdrop = true;
 		return false;
 	}
 
diff --git a/net/ipv6/netfilter/ip6t_frag.c b/net/ipv6/netfilter/ip6t_frag.c
index 972f699..6951d0d 100644
--- a/net/ipv6/netfilter/ip6t_frag.c
+++ b/net/ipv6/netfilter/ip6t_frag.c
@@ -35,27 +35,24 @@ id_match(u_int32_t min, u_int32_t max, u_int32_t id, bool invert)
 }
 
 static bool
-frag_mt6(const struct sk_buff *skb, const struct net_device *in,
-         const struct net_device *out, const struct xt_match *match,
-         const void *matchinfo, int offset, unsigned int protoff,
-         bool *hotdrop)
+frag_mt6(const struct sk_buff *skb, const struct xt_match_param *par)
 {
 	struct frag_hdr _frag;
 	const struct frag_hdr *fh;
-	const struct ip6t_frag *fraginfo = matchinfo;
+	const struct ip6t_frag *fraginfo = par->matchinfo;
 	unsigned int ptr;
 	int err;
 
 	err = ipv6_find_hdr(skb, &ptr, NEXTHDR_FRAGMENT, NULL);
 	if (err < 0) {
 		if (err != -ENOENT)
-			*hotdrop = true;
+			*par->hotdrop = true;
 		return false;
 	}
 
 	fh = skb_header_pointer(skb, ptr, sizeof(_frag), &_frag);
 	if (fh == NULL) {
-		*hotdrop = true;
+		*par->hotdrop = true;
 		return false;
 	}
 
diff --git a/net/ipv6/netfilter/ip6t_hbh.c b/net/ipv6/netfilter/ip6t_hbh.c
index d5edb51..d335197 100644
--- a/net/ipv6/netfilter/ip6t_hbh.c
+++ b/net/ipv6/netfilter/ip6t_hbh.c
@@ -42,14 +42,11 @@ MODULE_ALIAS("ip6t_dst");
  */
 
 static bool
-hbh_mt6(const struct sk_buff *skb, const struct net_device *in,
-        const struct net_device *out, const struct xt_match *match,
-        const void *matchinfo, int offset, unsigned int protoff,
-        bool *hotdrop)
+hbh_mt6(const struct sk_buff *skb, const struct xt_match_param *par)
 {
 	struct ipv6_opt_hdr _optsh;
 	const struct ipv6_opt_hdr *oh;
-	const struct ip6t_opts *optinfo = matchinfo;
+	const struct ip6t_opts *optinfo = par->matchinfo;
 	unsigned int temp;
 	unsigned int ptr;
 	unsigned int hdrlen = 0;
@@ -61,16 +58,16 @@ hbh_mt6(const struct sk_buff *skb, const struct net_device *in,
 	unsigned int optlen;
 	int err;
 
-	err = ipv6_find_hdr(skb, &ptr, match->data, NULL);
+	err = ipv6_find_hdr(skb, &ptr, par->match->data, NULL);
 	if (err < 0) {
 		if (err != -ENOENT)
-			*hotdrop = true;
+			*par->hotdrop = true;
 		return false;
 	}
 
 	oh = skb_header_pointer(skb, ptr, sizeof(_optsh), &_optsh);
 	if (oh == NULL) {
-		*hotdrop = true;
+		*par->hotdrop = true;
 		return false;
 	}
 
diff --git a/net/ipv6/netfilter/ip6t_hl.c b/net/ipv6/netfilter/ip6t_hl.c
index 25c1eb9..c964dca 100644
--- a/net/ipv6/netfilter/ip6t_hl.c
+++ b/net/ipv6/netfilter/ip6t_hl.c
@@ -19,12 +19,9 @@ MODULE_AUTHOR("Maciej Soltysiak <solt@dns.toxicfilms.tv>");
 MODULE_DESCRIPTION("Xtables: IPv6 Hop Limit field match");
 MODULE_LICENSE("GPL");
 
-static bool
-hl_mt6(const struct sk_buff *skb, const struct net_device *in,
-       const struct net_device *out, const struct xt_match *match,
-       const void *matchinfo, int offset, unsigned int protoff, bool *hotdrop)
+static bool hl_mt6(const struct sk_buff *skb, const struct xt_match_param *par)
 {
-	const struct ip6t_hl_info *info = matchinfo;
+	const struct ip6t_hl_info *info = par->matchinfo;
 	const struct ipv6hdr *ip6h = ipv6_hdr(skb);
 
 	switch (info->mode) {
diff --git a/net/ipv6/netfilter/ip6t_ipv6header.c b/net/ipv6/netfilter/ip6t_ipv6header.c
index ef0661a..6aaca51 100644
--- a/net/ipv6/netfilter/ip6t_ipv6header.c
+++ b/net/ipv6/netfilter/ip6t_ipv6header.c
@@ -27,12 +27,9 @@ MODULE_DESCRIPTION("Xtables: IPv6 header types match");
 MODULE_AUTHOR("Andras Kis-Szabo <kisza@sch.bme.hu>");
 
 static bool
-ipv6header_mt6(const struct sk_buff *skb, const struct net_device *in,
-               const struct net_device *out, const struct xt_match *match,
-               const void *matchinfo, int offset, unsigned int protoff,
-               bool *hotdrop)
+ipv6header_mt6(const struct sk_buff *skb, const struct xt_match_param *par)
 {
-	const struct ip6t_ipv6header_info *info = matchinfo;
+	const struct ip6t_ipv6header_info *info = par->matchinfo;
 	unsigned int temp;
 	int len;
 	u8 nexthdr;
diff --git a/net/ipv6/netfilter/ip6t_mh.c b/net/ipv6/netfilter/ip6t_mh.c
index dd87627..2803258 100644
--- a/net/ipv6/netfilter/ip6t_mh.c
+++ b/net/ipv6/netfilter/ip6t_mh.c
@@ -37,32 +37,29 @@ type_match(u_int8_t min, u_int8_t max, u_int8_t type, bool invert)
 	return (type >= min && type <= max) ^ invert;
 }
 
-static bool
-mh_mt6(const struct sk_buff *skb, const struct net_device *in,
-       const struct net_device *out, const struct xt_match *match,
-       const void *matchinfo, int offset, unsigned int protoff, bool *hotdrop)
+static bool mh_mt6(const struct sk_buff *skb, const struct xt_match_param *par)
 {
 	struct ip6_mh _mh;
 	const struct ip6_mh *mh;
-	const struct ip6t_mh *mhinfo = matchinfo;
+	const struct ip6t_mh *mhinfo = par->matchinfo;
 
 	/* Must not be a fragment. */
-	if (offset)
+	if (par->fragoff != 0)
 		return false;
 
-	mh = skb_header_pointer(skb, protoff, sizeof(_mh), &_mh);
+	mh = skb_header_pointer(skb, par->thoff, sizeof(_mh), &_mh);
 	if (mh == NULL) {
 		/* We've been asked to examine this packet, and we
 		   can't.  Hence, no choice but to drop. */
 		duprintf("Dropping evil MH tinygram.\n");
-		*hotdrop = true;
+		*par->hotdrop = true;
 		return false;
 	}
 
 	if (mh->ip6mh_proto != IPPROTO_NONE) {
 		duprintf("Dropping invalid MH Payload Proto: %u\n",
 			 mh->ip6mh_proto);
-		*hotdrop = true;
+		*par->hotdrop = true;
 		return false;
 	}
 
diff --git a/net/ipv6/netfilter/ip6t_rt.c b/net/ipv6/netfilter/ip6t_rt.c
index 7c544ae..9cf4b8a 100644
--- a/net/ipv6/netfilter/ip6t_rt.c
+++ b/net/ipv6/netfilter/ip6t_rt.c
@@ -36,14 +36,11 @@ segsleft_match(u_int32_t min, u_int32_t max, u_int32_t id, bool invert)
 	return r;
 }
 
-static bool
-rt_mt6(const struct sk_buff *skb, const struct net_device *in,
-       const struct net_device *out, const struct xt_match *match,
-       const void *matchinfo, int offset, unsigned int protoff, bool *hotdrop)
+static bool rt_mt6(const struct sk_buff *skb, const struct xt_match_param *par)
 {
 	struct ipv6_rt_hdr _route;
 	const struct ipv6_rt_hdr *rh;
-	const struct ip6t_rt *rtinfo = matchinfo;
+	const struct ip6t_rt *rtinfo = par->matchinfo;
 	unsigned int temp;
 	unsigned int ptr;
 	unsigned int hdrlen = 0;
@@ -55,13 +52,13 @@ rt_mt6(const struct sk_buff *skb, const struct net_device *in,
 	err = ipv6_find_hdr(skb, &ptr, NEXTHDR_ROUTING, NULL);
 	if (err < 0) {
 		if (err != -ENOENT)
-			*hotdrop = true;
+			*par->hotdrop = true;
 		return false;
 	}
 
 	rh = skb_header_pointer(skb, ptr, sizeof(_route), &_route);
 	if (rh == NULL) {
-		*hotdrop = true;
+		*par->hotdrop = true;
 		return false;
 	}