[PATCH 34/51] netfilter: ebtables: add ebt_get_target and ebt_get_target_c

[Pablo Neira Ayuso]

From: Taehee Yoo <ap420...@gmail.com>

ebt_get_target similar to {ip/ip6/arp}t_get_target.
and ebt_get_target_c similar to {ip/ip6/arp}t_get_target_c.

Signed-off-by: Taehee Yoo <ap420...@gmail.com>
Signed-off-by: Pablo Neira Ayuso <pa...@netfilter.org>
---
 include/uapi/linux/netfilter_bridge/ebtables.h |  6 ++++++
 net/bridge/netfilter/ebtables.c                | 22 +++++++++++++---------
 2 files changed, 19 insertions(+), 9 deletions(-)

diff --git a/include/uapi/linux/netfilter_bridge/ebtables.h 
b/include/uapi/linux/netfilter_bridge/ebtables.h
index 0c7dc8315013..3b86c14ea49d 100644
--- a/include/uapi/linux/netfilter_bridge/ebtables.h
+++ b/include/uapi/linux/netfilter_bridge/ebtables.h
@@ -191,6 +191,12 @@ struct ebt_entry {
        unsigned char elems[0] __attribute__ ((aligned (__alignof__(struct 
ebt_replace))));
 };
 
+static __inline__ struct ebt_entry_target *
+ebt_get_target(struct ebt_entry *e)
+{
+       return (void *)e + e->target_offset;
+}
+
 /* {g,s}etsockopt numbers */
 #define EBT_BASE_CTL            128
 
diff --git a/net/bridge/netfilter/ebtables.c b/net/bridge/netfilter/ebtables.c
index 7c07221369c0..9be240129448 100644
--- a/net/bridge/netfilter/ebtables.c
+++ b/net/bridge/netfilter/ebtables.c
@@ -177,6 +177,12 @@ struct ebt_entry *ebt_next_entry(const struct ebt_entry 
*entry)
        return (void *)entry + entry->next_offset;
 }
 
+static inline const struct ebt_entry_target *
+ebt_get_target_c(const struct ebt_entry *e)
+{
+       return ebt_get_target((struct ebt_entry *)e);
+}
+
 /* Do some firewalling */
 unsigned int ebt_do_table(struct sk_buff *skb,
                          const struct nf_hook_state *state,
@@ -230,8 +236,7 @@ unsigned int ebt_do_table(struct sk_buff *skb,
                 */
                EBT_WATCHER_ITERATE(point, ebt_do_watcher, skb, &acpar);
 
-               t = (struct ebt_entry_target *)
-                  (((char *)point) + point->target_offset);
+               t = ebt_get_target_c(point);
                /* standard target */
                if (!t->u.target->target)
                        verdict = ((struct ebt_standard_target *)t)->verdict;
@@ -637,7 +642,7 @@ ebt_cleanup_entry(struct ebt_entry *e, struct net *net, 
unsigned int *cnt)
                return 1;
        EBT_WATCHER_ITERATE(e, ebt_cleanup_watcher, net, NULL);
        EBT_MATCH_ITERATE(e, ebt_cleanup_match, net, NULL);
-       t = (struct ebt_entry_target *)(((char *)e) + e->target_offset);
+       t = ebt_get_target(e);
 
        par.net      = net;
        par.target   = t->u.target;
@@ -716,7 +721,7 @@ ebt_check_entry(struct ebt_entry *e, struct net *net,
        ret = EBT_WATCHER_ITERATE(e, ebt_check_watcher, &tgpar, &j);
        if (ret != 0)
                goto cleanup_watchers;
-       t = (struct ebt_entry_target *)(((char *)e) + e->target_offset);
+       t = ebt_get_target(e);
        gap = e->next_offset - e->target_offset;
 
        target = xt_request_find_target(NFPROTO_BRIDGE, t->u.name, 0);
@@ -789,8 +794,7 @@ static int check_chainloops(const struct ebt_entries 
*chain, struct ebt_cl_stack
                        if (pos == nentries)
                                continue;
                }
-               t = (struct ebt_entry_target *)
-                  (((char *)e) + e->target_offset);
+               t = ebt_get_target_c(e);
                if (strcmp(t->u.name, EBT_STANDARD_TARGET))
                        goto letscontinue;
                if (e->target_offset + sizeof(struct ebt_standard_target) >
@@ -1396,7 +1400,7 @@ static inline int ebt_entry_to_user(struct ebt_entry *e, 
const char *base,
                return -EFAULT;
 
        hlp = ubase + (((char *)e + e->target_offset) - base);
-       t = (struct ebt_entry_target *)(((char *)e) + e->target_offset);
+       t = ebt_get_target_c(e);
 
        ret = EBT_MATCH_ITERATE(e, ebt_match_to_user, base, ubase);
        if (ret != 0)
@@ -1737,7 +1741,7 @@ static int compat_copy_entry_to_user(struct ebt_entry *e, 
void __user **dstptr,
                return ret;
        target_offset = e->target_offset - (origsize - *size);
 
-       t = (struct ebt_entry_target *) ((char *) e + e->target_offset);
+       t = ebt_get_target(e);
 
        ret = compat_target_to_user(t, dstptr, size);
        if (ret)
@@ -1785,7 +1789,7 @@ static int compat_calc_entry(const struct ebt_entry *e,
        EBT_MATCH_ITERATE(e, compat_calc_match, &off);
        EBT_WATCHER_ITERATE(e, compat_calc_watcher, &off);
 
-       t = (const struct ebt_entry_target *) ((char *) e + e->target_offset);
+       t = ebt_get_target_c(e);
 
        off += xt_compat_target_offset(t->u.target);
        off += ebt_compat_entry_padsize();
-- 
2.11.0