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etherdevice.h & bridge: netfilter: Add and use ether_addr_equal_masked
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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 <[email protected]>
Acked-by: David S. Miller <[email protected]>
Signed-off-by: Pablo Neira Ayuso <[email protected]>
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@JoePerches @ummakynes
JoePerches authored and ummakynes committed Jul 1, 2016
1 parent 468b021 commit 4ae89ad
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Showing 4 changed files with 57 additions and 49 deletions.
23 changes: 23 additions & 0 deletions include/linux/etherdevice.h
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Original file line number Diff line number Diff line change
Expand Up @@ -373,6 +373,29 @@ static inline bool ether_addr_equal_unaligned(const u8 *addr1, const u8 *addr2)
#endif
}

/**
* 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
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17 changes: 6 additions & 11 deletions net/bridge/netfilter/ebt_arp.c
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Original file line number Diff line number Diff line change
Expand Up @@ -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;
Expand All @@ -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;
}

Expand All @@ -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;
}
}
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49 changes: 22 additions & 27 deletions net/bridge/netfilter/ebt_stp.c
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Original file line number Diff line number Diff line change
Expand Up @@ -46,74 +46,69 @@ 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) &&
FWINV(c->flags != stpc->flags, EBT_STP_FLAGS))
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;
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17 changes: 6 additions & 11 deletions net/bridge/netfilter/ebtables.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -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);
Expand All @@ -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;
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