[PATCH] etherdevice.h & bridge: netfilter: Add and use ether_addr_equal_masked
From: Joe Perches
Date: Fri Jun 24 2016 - 14:32:36 EST
There are code duplications of a masked ethernet address comparison here
so make it a separate function instead.
Miscellanea:
o Neaten alignment of FWINV macro uses to make it clearer for the reader
Signed-off-by: Joe Perches <joe@xxxxxxxxxxx>
---
include/linux/etherdevice.h | 23 +++++++++++++++++++
net/bridge/netfilter/ebt_arp.c | 17 +++++---------
net/bridge/netfilter/ebt_stp.c | 49 ++++++++++++++++++-----------------------
net/bridge/netfilter/ebtables.c | 17 +++++---------
4 files changed, 57 insertions(+), 49 deletions(-)
diff --git a/include/linux/etherdevice.h b/include/linux/etherdevice.h
index 37ff4a6..6fec9e8 100644
--- a/include/linux/etherdevice.h
+++ b/include/linux/etherdevice.h
@@ -374,6 +374,29 @@ static inline bool ether_addr_equal_unaligned(const u8 *addr1, const u8 *addr2)
}
/**
+ * ether_addr_equal_masked - Compare two Ethernet addresses with a mask
+ * @addr1: Pointer to a six-byte array containing the 1st Ethernet address
+ * @addr2: Pointer to a six-byte array containing the 2nd Ethernet address
+ * @mask: Pointer to a six-byte array containing the Ethernet address bitmask
+ *
+ * Compare two Ethernet addresses with a mask, returns true if for every bit
+ * set in the bitmask the equivalent bits in the ethernet addresses are equal.
+ * Using a mask with all bits set is a slower ether_addr_equal.
+ */
+static inline bool ether_addr_equal_masked(const u8 *addr1, const u8 *addr2,
+ const u8 *mask)
+{
+ int i;
+
+ for (i = 0; i < ETH_ALEN; i++) {
+ if ((addr1[i] ^ addr2[i]) & mask[i])
+ return false;
+ }
+
+ return true;
+}
+
+/**
* is_etherdev_addr - Tell if given Ethernet address belongs to the device.
* @dev: Pointer to a device structure
* @addr: Pointer to a six-byte array containing the Ethernet address
diff --git a/net/bridge/netfilter/ebt_arp.c b/net/bridge/netfilter/ebt_arp.c
index cd457b8..cca0a89 100644
--- a/net/bridge/netfilter/ebt_arp.c
+++ b/net/bridge/netfilter/ebt_arp.c
@@ -65,7 +65,6 @@ ebt_arp_mt(const struct sk_buff *skb, struct xt_action_param *par)
if (info->bitmask & (EBT_ARP_SRC_MAC | EBT_ARP_DST_MAC)) {
const unsigned char *mp;
unsigned char _mac[ETH_ALEN];
- uint8_t verdict, i;
if (ah->ar_hln != ETH_ALEN || ah->ar_hrd != htons(ARPHRD_ETHER))
return false;
@@ -74,11 +73,9 @@ ebt_arp_mt(const struct sk_buff *skb, struct xt_action_param *par)
sizeof(_mac), &_mac);
if (mp == NULL)
return false;
- verdict = 0;
- for (i = 0; i < 6; i++)
- verdict |= (mp[i] ^ info->smaddr[i]) &
- info->smmsk[i];
- if (FWINV(verdict != 0, EBT_ARP_SRC_MAC))
+ if (FWINV(!ether_addr_equal_masked(mp, info->smaddr,
+ info->smmsk),
+ EBT_ARP_SRC_MAC))
return false;
}
@@ -88,11 +85,9 @@ ebt_arp_mt(const struct sk_buff *skb, struct xt_action_param *par)
sizeof(_mac), &_mac);
if (mp == NULL)
return false;
- verdict = 0;
- for (i = 0; i < 6; i++)
- verdict |= (mp[i] ^ info->dmaddr[i]) &
- info->dmmsk[i];
- if (FWINV(verdict != 0, EBT_ARP_DST_MAC))
+ if (FWINV(!ether_addr_equal_masked(mp, info->dmaddr,
+ info->dmmsk),
+ EBT_ARP_DST_MAC))
return false;
}
}
diff --git a/net/bridge/netfilter/ebt_stp.c b/net/bridge/netfilter/ebt_stp.c
index e77f90b..45f73d5 100644
--- a/net/bridge/netfilter/ebt_stp.c
+++ b/net/bridge/netfilter/ebt_stp.c
@@ -46,7 +46,6 @@ static bool ebt_filter_config(const struct ebt_stp_info *info,
const struct ebt_stp_config_info *c;
u16 v16;
u32 v32;
- int verdict, i;
c = &info->config;
if ((info->bitmask & EBT_STP_FLAGS) &&
@@ -54,66 +53,62 @@ static bool ebt_filter_config(const struct ebt_stp_info *info,
return false;
if (info->bitmask & EBT_STP_ROOTPRIO) {
v16 = NR16(stpc->root);
- if (FWINV(v16 < c->root_priol ||
- v16 > c->root_priou, EBT_STP_ROOTPRIO))
+ if (FWINV(v16 < c->root_priol || v16 > c->root_priou,
+ EBT_STP_ROOTPRIO))
return false;
}
if (info->bitmask & EBT_STP_ROOTADDR) {
- verdict = 0;
- for (i = 0; i < 6; i++)
- verdict |= (stpc->root[2+i] ^ c->root_addr[i]) &
- c->root_addrmsk[i];
- if (FWINV(verdict != 0, EBT_STP_ROOTADDR))
+ if (FWINV(!ether_addr_equal_masked(&stpc->root[2], c->root_addr,
+ c->root_addrmsk),
+ EBT_STP_ROOTADDR))
return false;
}
if (info->bitmask & EBT_STP_ROOTCOST) {
v32 = NR32(stpc->root_cost);
- if (FWINV(v32 < c->root_costl ||
- v32 > c->root_costu, EBT_STP_ROOTCOST))
+ if (FWINV(v32 < c->root_costl || v32 > c->root_costu,
+ EBT_STP_ROOTCOST))
return false;
}
if (info->bitmask & EBT_STP_SENDERPRIO) {
v16 = NR16(stpc->sender);
- if (FWINV(v16 < c->sender_priol ||
- v16 > c->sender_priou, EBT_STP_SENDERPRIO))
+ if (FWINV(v16 < c->sender_priol || v16 > c->sender_priou,
+ EBT_STP_SENDERPRIO))
return false;
}
if (info->bitmask & EBT_STP_SENDERADDR) {
- verdict = 0;
- for (i = 0; i < 6; i++)
- verdict |= (stpc->sender[2+i] ^ c->sender_addr[i]) &
- c->sender_addrmsk[i];
- if (FWINV(verdict != 0, EBT_STP_SENDERADDR))
+ if (FWINV(!ether_addr_equal_masked(&stpc->sender[2],
+ c->sender_addr,
+ c->sender_addrmsk),
+ EBT_STP_SENDERADDR))
return false;
}
if (info->bitmask & EBT_STP_PORT) {
v16 = NR16(stpc->port);
- if (FWINV(v16 < c->portl ||
- v16 > c->portu, EBT_STP_PORT))
+ if (FWINV(v16 < c->portl || v16 > c->portu, EBT_STP_PORT))
return false;
}
if (info->bitmask & EBT_STP_MSGAGE) {
v16 = NR16(stpc->msg_age);
- if (FWINV(v16 < c->msg_agel ||
- v16 > c->msg_ageu, EBT_STP_MSGAGE))
+ if (FWINV(v16 < c->msg_agel || v16 > c->msg_ageu,
+ EBT_STP_MSGAGE))
return false;
}
if (info->bitmask & EBT_STP_MAXAGE) {
v16 = NR16(stpc->max_age);
- if (FWINV(v16 < c->max_agel ||
- v16 > c->max_ageu, EBT_STP_MAXAGE))
+ if (FWINV(v16 < c->max_agel || v16 > c->max_ageu,
+ EBT_STP_MAXAGE))
return false;
}
if (info->bitmask & EBT_STP_HELLOTIME) {
v16 = NR16(stpc->hello_time);
- if (FWINV(v16 < c->hello_timel ||
- v16 > c->hello_timeu, EBT_STP_HELLOTIME))
+ if (FWINV(v16 < c->hello_timel || v16 > c->hello_timeu,
+ EBT_STP_HELLOTIME))
return false;
}
if (info->bitmask & EBT_STP_FWDD) {
v16 = NR16(stpc->forward_delay);
- if (FWINV(v16 < c->forward_delayl ||
- v16 > c->forward_delayu, EBT_STP_FWDD))
+ if (FWINV(v16 < c->forward_delayl || v16 > c->forward_delayu,
+ EBT_STP_FWDD))
return false;
}
return true;
diff --git a/net/bridge/netfilter/ebtables.c b/net/bridge/netfilter/ebtables.c
index 5a61f35..5721a25 100644
--- a/net/bridge/netfilter/ebtables.c
+++ b/net/bridge/netfilter/ebtables.c
@@ -130,7 +130,6 @@ ebt_basic_match(const struct ebt_entry *e, const struct sk_buff *skb,
const struct ethhdr *h = eth_hdr(skb);
const struct net_bridge_port *p;
__be16 ethproto;
- int verdict, i;
if (skb_vlan_tag_present(skb))
ethproto = htons(ETH_P_8021Q);
@@ -157,19 +156,15 @@ ebt_basic_match(const struct ebt_entry *e, const struct sk_buff *skb,
return 1;
if (e->bitmask & EBT_SOURCEMAC) {
- verdict = 0;
- for (i = 0; i < 6; i++)
- verdict |= (h->h_source[i] ^ e->sourcemac[i]) &
- e->sourcemsk[i];
- if (FWINV2(verdict != 0, EBT_ISOURCE))
+ if (FWINV2(!ether_addr_equal_masked(h->h_source,
+ e->sourcemac, e->sourcemsk),
+ EBT_ISOURCE))
return 1;
}
if (e->bitmask & EBT_DESTMAC) {
- verdict = 0;
- for (i = 0; i < 6; i++)
- verdict |= (h->h_dest[i] ^ e->destmac[i]) &
- e->destmsk[i];
- if (FWINV2(verdict != 0, EBT_IDEST))
+ if (FWINV2(!ether_addr_equal_masked(h->h_dest,
+ e->destmac, e->destmsk),
+ EBT_IDEST))
return 1;
}
return 0;
--
2.8.0.rc4.16.g56331f8