netfilter: xtables: consolidate open-coded logic

Signed-off-by: Jan Engelhardt <jengelh@medozas.de>

4 files changed, 40 insertions, 18 deletions

diff --git a/net/bridge/netfilter/ebtables.c b/net/bridge/netfilter/ebtables.c
index 820252aee81f..24555834d431 100644
--- a/net/bridge/netfilter/ebtables.c
+++ b/net/bridge/netfilter/ebtables.c
@@ -142,6 +142,12 @@ static inline int ebt_basic_match(struct ebt_entry *e, struct ethhdr *h,
         return 0;
 }
 
+static inline __pure
+struct ebt_entry *ebt_next_entry(const struct ebt_entry *entry)
+{
+        return (void *)entry + entry->next_offset;
+}
+
 /* Do some firewalling */
 unsigned int ebt_do_table (unsigned int hook, struct sk_buff *skb,
    const struct net_device *in, const struct net_device *out,
@@ -249,8 +255,7 @@ letsreturn:
                 /* jump to a udc */
                 cs[sp].n = i + 1;
                 cs[sp].chaininfo = chaininfo;
-                cs[sp].e = (struct ebt_entry *)
-                   (((char *)point) + point->next_offset);
+                cs[sp].e = ebt_next_entry(point);
                 i = 0;
                 chaininfo = (struct ebt_entries *) (base + verdict);
 #ifdef CONFIG_NETFILTER_DEBUG
@@ -266,8 +271,7 @@ letsreturn:
                 sp++;
                 continue;
 letscontinue:
-                point = (struct ebt_entry *)
-                   (((char *)point) + point->next_offset);
+                point = ebt_next_entry(point);
                 i++;
         }
 
@@ -787,7 +791,7 @@ static int check_chainloops(struct ebt_entries *chain, struct ebt_cl_stack *cl_s
                         /* this can't be 0, so the loop test is correct */
                         cl_s[i].cs.n = pos + 1;
                         pos = 0;
-                        cl_s[i].cs.e = ((void *)e + e->next_offset);
+                        cl_s[i].cs.e = ebt_next_entry(e);
                         e = (struct ebt_entry *)(hlp2->data);
                         nentries = hlp2->nentries;
                         cl_s[i].from = chain_nr;
@@ -797,7 +801,7 @@ static int check_chainloops(struct ebt_entries *chain, struct ebt_cl_stack *cl_s
                         continue;
                 }
 letscontinue:
-                e = (void *)e + e->next_offset;
+                e = ebt_next_entry(e);
                 pos++;
         }
         return 0;
diff --git a/net/ipv4/netfilter/arp_tables.c b/net/ipv4/netfilter/arp_tables.c
index 831fe1879dc0..940e54ba21b3 100644
--- a/net/ipv4/netfilter/arp_tables.c
+++ b/net/ipv4/netfilter/arp_tables.c
@@ -231,6 +231,12 @@ static inline struct arpt_entry *get_entry(void *base, unsigned int offset)
         return (struct arpt_entry *)(base + offset);
 }
 
+static inline __pure
+struct arpt_entry *arpt_next_entry(const struct arpt_entry *entry)
+{
+        return (void *)entry + entry->next_offset;
+}
+
 unsigned int arpt_do_table(struct sk_buff *skb,
                            unsigned int hook,
                            const struct net_device *in,
@@ -295,10 +301,10 @@ unsigned int arpt_do_table(struct sk_buff *skb,
                                         continue;
                                 }
                                 if (table_base + v
-                                    != (void *)e + e->next_offset) {
+                                    != arpt_next_entry(e)) {
                                         /* Save old back ptr in next entry */
                                         struct arpt_entry *next
-                                                = (void *)e + e->next_offset;
+                                                = arpt_next_entry(e);
                                         next->comefrom =
                                                 (void *)back - table_base;
 
@@ -320,13 +326,13 @@ unsigned int arpt_do_table(struct sk_buff *skb,
                                 arp = arp_hdr(skb);
 
                                 if (verdict == ARPT_CONTINUE)
-                                        e = (void *)e + e->next_offset;
+                                        e = arpt_next_entry(e);
                                 else
                                         /* Verdict */
                                         break;
                         }
                 } else {
-                        e = (void *)e + e->next_offset;
+                        e = arpt_next_entry(e);
                 }
         } while (!hotdrop);
         xt_info_rdunlock_bh();
diff --git a/net/ipv4/netfilter/ip_tables.c b/net/ipv4/netfilter/ip_tables.c
index 16b7c09c0366..7ec4e4092755 100644
--- a/net/ipv4/netfilter/ip_tables.c
+++ b/net/ipv4/netfilter/ip_tables.c
@@ -297,6 +297,12 @@ static void trace_packet(struct sk_buff *skb,
 }
 #endif
 
+static inline __pure
+struct ipt_entry *ipt_next_entry(const struct ipt_entry *entry)
+{
+        return (void *)entry + entry->next_offset;
+}
+
 /* Returns one of the generic firewall policies, like NF_ACCEPT. */
 unsigned int
 ipt_do_table(struct sk_buff *skb,
@@ -385,11 +391,11 @@ ipt_do_table(struct sk_buff *skb,
                                                          back->comefrom);
                                         continue;
                                 }
-                                if (table_base + v != (void *)e + e->next_offset
+                                if (table_base + v != ipt_next_entry(e)
                                     && !(e->ip.flags & IPT_F_GOTO)) {
                                         /* Save old back ptr in next entry */
                                         struct ipt_entry *next
-                                                = (void *)e + e->next_offset;
+                                                = ipt_next_entry(e);
                                         next->comefrom
                                                 = (void *)back - table_base;
                                         /* set back pointer to next entry */
@@ -424,7 +430,7 @@ ipt_do_table(struct sk_buff *skb,
                                 datalen = skb->len - ip->ihl * 4;
 
                                 if (verdict == IPT_CONTINUE)
-                                        e = (void *)e + e->next_offset;
+                                        e = ipt_next_entry(e);
                                 else
                                         /* Verdict */
                                         break;
@@ -432,7 +438,7 @@ ipt_do_table(struct sk_buff *skb,
                 } else {
 
                 no_match:
-                        e = (void *)e + e->next_offset;
+                        e = ipt_next_entry(e);
                 }
         } while (!hotdrop);
         xt_info_rdunlock_bh();
diff --git a/net/ipv6/netfilter/ip6_tables.c b/net/ipv6/netfilter/ip6_tables.c
index 4853a3d542b7..9176e98ace7a 100644
--- a/net/ipv6/netfilter/ip6_tables.c
+++ b/net/ipv6/netfilter/ip6_tables.c
@@ -329,6 +329,12 @@ static void trace_packet(struct sk_buff *skb,
 }
 #endif
 
+static inline __pure struct ip6t_entry *
+ip6t_next_entry(const struct ip6t_entry *entry)
+{
+        return (void *)entry + entry->next_offset;
+}
+
 /* Returns one of the generic firewall policies, like NF_ACCEPT. */
 unsigned int
 ip6t_do_table(struct sk_buff *skb,
@@ -414,11 +420,11 @@ ip6t_do_table(struct sk_buff *skb,
                                                          back->comefrom);
                                         continue;
                                 }
-                                if (table_base + v != (void *)e + e->next_offset
+                                if (table_base + v != ip6t_next_entry(e)
                                     && !(e->ipv6.flags & IP6T_F_GOTO)) {
                                         /* Save old back ptr in next entry */
                                         struct ip6t_entry *next
-                                                = (void *)e + e->next_offset;
+                                                = ip6t_next_entry(e);
                                         next->comefrom
                                                 = (void *)back - table_base;
                                         /* set back pointer to next entry */
@@ -451,7 +457,7 @@ ip6t_do_table(struct sk_buff *skb,
                                         = 0x57acc001;
 #endif
                                 if (verdict == IP6T_CONTINUE)
-                                        e = (void *)e + e->next_offset;
+                                        e = ip6t_next_entry(e);
                                 else
                                         /* Verdict */
                                         break;
@@ -459,7 +465,7 @@ ip6t_do_table(struct sk_buff *skb,
                 } else {
 
                 no_match:
-                        e = (void *)e + e->next_offset;
+                        e = ip6t_next_entry(e);
                 }
         } while (!hotdrop);