netfilter: xtables: consolidate open-coded logic

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

2 files changed, 20 insertions, 8 deletions

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();