alistair23-linux/include/linux/etherdevice.h
Alexander Duyck 9c0c112422 net: Add functions for handling padding frame and adding to length
This patch adds two new helper functions skb_put_padto and eth_skb_pad.
These functions deviate from the standard skb_pad or skb_padto in that they
will also update the length and tail pointers so that they reflect the
padding added to the frame.

The eth_skb_pad helper is meant to be used with Ethernet devices to update
either Rx or Tx frames so that they report the correct size.  The
skb_put_padto helper is meant to be used primarily in the transmit path for
network devices that need frames to be padded up to some minimum size and
don't wish to simply update the length somewhere external to the frame.

The motivation behind this is that there are a number of implementations
throughout the network device drivers that are all doing the same thing,
but each a little bit differently and as a result several implementations
contain bugs such as updating the length without updating the tail offset
and other similar issues.

Signed-off-by: Alexander Duyck <alexander.h.duyck@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2014-12-08 20:47:41 -05:00

408 lines
12 KiB
C

/*
* INET An implementation of the TCP/IP protocol suite for the LINUX
* operating system. NET is implemented using the BSD Socket
* interface as the means of communication with the user level.
*
* Definitions for the Ethernet handlers.
*
* Version: @(#)eth.h 1.0.4 05/13/93
*
* Authors: Ross Biro
* Fred N. van Kempen, <waltje@uWalt.NL.Mugnet.ORG>
*
* Relocated to include/linux where it belongs by Alan Cox
* <gw4pts@gw4pts.ampr.org>
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version
* 2 of the License, or (at your option) any later version.
*
*/
#ifndef _LINUX_ETHERDEVICE_H
#define _LINUX_ETHERDEVICE_H
#include <linux/if_ether.h>
#include <linux/netdevice.h>
#include <linux/random.h>
#include <asm/unaligned.h>
#include <asm/bitsperlong.h>
#ifdef __KERNEL__
u32 eth_get_headlen(void *data, unsigned int max_len);
__be16 eth_type_trans(struct sk_buff *skb, struct net_device *dev);
extern const struct header_ops eth_header_ops;
int eth_header(struct sk_buff *skb, struct net_device *dev, unsigned short type,
const void *daddr, const void *saddr, unsigned len);
int eth_rebuild_header(struct sk_buff *skb);
int eth_header_parse(const struct sk_buff *skb, unsigned char *haddr);
int eth_header_cache(const struct neighbour *neigh, struct hh_cache *hh,
__be16 type);
void eth_header_cache_update(struct hh_cache *hh, const struct net_device *dev,
const unsigned char *haddr);
int eth_prepare_mac_addr_change(struct net_device *dev, void *p);
void eth_commit_mac_addr_change(struct net_device *dev, void *p);
int eth_mac_addr(struct net_device *dev, void *p);
int eth_change_mtu(struct net_device *dev, int new_mtu);
int eth_validate_addr(struct net_device *dev);
struct net_device *alloc_etherdev_mqs(int sizeof_priv, unsigned int txqs,
unsigned int rxqs);
#define alloc_etherdev(sizeof_priv) alloc_etherdev_mq(sizeof_priv, 1)
#define alloc_etherdev_mq(sizeof_priv, count) alloc_etherdev_mqs(sizeof_priv, count, count)
/* Reserved Ethernet Addresses per IEEE 802.1Q */
static const u8 eth_reserved_addr_base[ETH_ALEN] __aligned(2) =
{ 0x01, 0x80, 0xc2, 0x00, 0x00, 0x00 };
/**
* is_link_local_ether_addr - Determine if given Ethernet address is link-local
* @addr: Pointer to a six-byte array containing the Ethernet address
*
* Return true if address is link local reserved addr (01:80:c2:00:00:0X) per
* IEEE 802.1Q 8.6.3 Frame filtering.
*
* Please note: addr must be aligned to u16.
*/
static inline bool is_link_local_ether_addr(const u8 *addr)
{
__be16 *a = (__be16 *)addr;
static const __be16 *b = (const __be16 *)eth_reserved_addr_base;
static const __be16 m = cpu_to_be16(0xfff0);
#if defined(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS)
return (((*(const u32 *)addr) ^ (*(const u32 *)b)) |
((a[2] ^ b[2]) & m)) == 0;
#else
return ((a[0] ^ b[0]) | (a[1] ^ b[1]) | ((a[2] ^ b[2]) & m)) == 0;
#endif
}
/**
* is_zero_ether_addr - Determine if give Ethernet address is all zeros.
* @addr: Pointer to a six-byte array containing the Ethernet address
*
* Return true if the address is all zeroes.
*
* Please note: addr must be aligned to u16.
*/
static inline bool is_zero_ether_addr(const u8 *addr)
{
#if defined(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS)
return ((*(const u32 *)addr) | (*(const u16 *)(addr + 4))) == 0;
#else
return (*(const u16 *)(addr + 0) |
*(const u16 *)(addr + 2) |
*(const u16 *)(addr + 4)) == 0;
#endif
}
/**
* is_multicast_ether_addr - Determine if the Ethernet address is a multicast.
* @addr: Pointer to a six-byte array containing the Ethernet address
*
* Return true if the address is a multicast address.
* By definition the broadcast address is also a multicast address.
*/
static inline bool is_multicast_ether_addr(const u8 *addr)
{
return 0x01 & addr[0];
}
/**
* is_local_ether_addr - Determine if the Ethernet address is locally-assigned one (IEEE 802).
* @addr: Pointer to a six-byte array containing the Ethernet address
*
* Return true if the address is a local address.
*/
static inline bool is_local_ether_addr(const u8 *addr)
{
return 0x02 & addr[0];
}
/**
* is_broadcast_ether_addr - Determine if the Ethernet address is broadcast
* @addr: Pointer to a six-byte array containing the Ethernet address
*
* Return true if the address is the broadcast address.
*
* Please note: addr must be aligned to u16.
*/
static inline bool is_broadcast_ether_addr(const u8 *addr)
{
return (*(const u16 *)(addr + 0) &
*(const u16 *)(addr + 2) &
*(const u16 *)(addr + 4)) == 0xffff;
}
/**
* is_unicast_ether_addr - Determine if the Ethernet address is unicast
* @addr: Pointer to a six-byte array containing the Ethernet address
*
* Return true if the address is a unicast address.
*/
static inline bool is_unicast_ether_addr(const u8 *addr)
{
return !is_multicast_ether_addr(addr);
}
/**
* is_valid_ether_addr - Determine if the given Ethernet address is valid
* @addr: Pointer to a six-byte array containing the Ethernet address
*
* Check that the Ethernet address (MAC) is not 00:00:00:00:00:00, is not
* a multicast address, and is not FF:FF:FF:FF:FF:FF.
*
* Return true if the address is valid.
*
* Please note: addr must be aligned to u16.
*/
static inline bool is_valid_ether_addr(const u8 *addr)
{
/* FF:FF:FF:FF:FF:FF is a multicast address so we don't need to
* explicitly check for it here. */
return !is_multicast_ether_addr(addr) && !is_zero_ether_addr(addr);
}
/**
* eth_random_addr - Generate software assigned random Ethernet address
* @addr: Pointer to a six-byte array containing the Ethernet address
*
* Generate a random Ethernet address (MAC) that is not multicast
* and has the local assigned bit set.
*/
static inline void eth_random_addr(u8 *addr)
{
get_random_bytes(addr, ETH_ALEN);
addr[0] &= 0xfe; /* clear multicast bit */
addr[0] |= 0x02; /* set local assignment bit (IEEE802) */
}
#define random_ether_addr(addr) eth_random_addr(addr)
/**
* eth_broadcast_addr - Assign broadcast address
* @addr: Pointer to a six-byte array containing the Ethernet address
*
* Assign the broadcast address to the given address array.
*/
static inline void eth_broadcast_addr(u8 *addr)
{
memset(addr, 0xff, ETH_ALEN);
}
/**
* eth_zero_addr - Assign zero address
* @addr: Pointer to a six-byte array containing the Ethernet address
*
* Assign the zero address to the given address array.
*/
static inline void eth_zero_addr(u8 *addr)
{
memset(addr, 0x00, ETH_ALEN);
}
/**
* eth_hw_addr_random - Generate software assigned random Ethernet and
* set device flag
* @dev: pointer to net_device structure
*
* Generate a random Ethernet address (MAC) to be used by a net device
* and set addr_assign_type so the state can be read by sysfs and be
* used by userspace.
*/
static inline void eth_hw_addr_random(struct net_device *dev)
{
dev->addr_assign_type = NET_ADDR_RANDOM;
eth_random_addr(dev->dev_addr);
}
/**
* ether_addr_copy - Copy an Ethernet address
* @dst: Pointer to a six-byte array Ethernet address destination
* @src: Pointer to a six-byte array Ethernet address source
*
* Please note: dst & src must both be aligned to u16.
*/
static inline void ether_addr_copy(u8 *dst, const u8 *src)
{
#if defined(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS)
*(u32 *)dst = *(const u32 *)src;
*(u16 *)(dst + 4) = *(const u16 *)(src + 4);
#else
u16 *a = (u16 *)dst;
const u16 *b = (const u16 *)src;
a[0] = b[0];
a[1] = b[1];
a[2] = b[2];
#endif
}
/**
* eth_hw_addr_inherit - Copy dev_addr from another net_device
* @dst: pointer to net_device to copy dev_addr to
* @src: pointer to net_device to copy dev_addr from
*
* Copy the Ethernet address from one net_device to another along with
* the address attributes (addr_assign_type).
*/
static inline void eth_hw_addr_inherit(struct net_device *dst,
struct net_device *src)
{
dst->addr_assign_type = src->addr_assign_type;
ether_addr_copy(dst->dev_addr, src->dev_addr);
}
/**
* ether_addr_equal - Compare two Ethernet addresses
* @addr1: Pointer to a six-byte array containing the Ethernet address
* @addr2: Pointer other six-byte array containing the Ethernet address
*
* Compare two Ethernet addresses, returns true if equal
*
* Please note: addr1 & addr2 must both be aligned to u16.
*/
static inline bool ether_addr_equal(const u8 *addr1, const u8 *addr2)
{
#if defined(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS)
u32 fold = ((*(const u32 *)addr1) ^ (*(const u32 *)addr2)) |
((*(const u16 *)(addr1 + 4)) ^ (*(const u16 *)(addr2 + 4)));
return fold == 0;
#else
const u16 *a = (const u16 *)addr1;
const u16 *b = (const u16 *)addr2;
return ((a[0] ^ b[0]) | (a[1] ^ b[1]) | (a[2] ^ b[2])) == 0;
#endif
}
/**
* ether_addr_equal_64bits - Compare two Ethernet addresses
* @addr1: Pointer to an array of 8 bytes
* @addr2: Pointer to an other array of 8 bytes
*
* Compare two Ethernet addresses, returns true if equal, false otherwise.
*
* The function doesn't need any conditional branches and possibly uses
* word memory accesses on CPU allowing cheap unaligned memory reads.
* arrays = { byte1, byte2, byte3, byte4, byte5, byte6, pad1, pad2 }
*
* Please note that alignment of addr1 & addr2 are only guaranteed to be 16 bits.
*/
static inline bool ether_addr_equal_64bits(const u8 addr1[6+2],
const u8 addr2[6+2])
{
#if defined(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS) && BITS_PER_LONG == 64
u64 fold = (*(const u64 *)addr1) ^ (*(const u64 *)addr2);
#ifdef __BIG_ENDIAN
return (fold >> 16) == 0;
#else
return (fold << 16) == 0;
#endif
#else
return ether_addr_equal(addr1, addr2);
#endif
}
/**
* ether_addr_equal_unaligned - Compare two not u16 aligned Ethernet addresses
* @addr1: Pointer to a six-byte array containing the Ethernet address
* @addr2: Pointer other six-byte array containing the Ethernet address
*
* Compare two Ethernet addresses, returns true if equal
*
* Please note: Use only when any Ethernet address may not be u16 aligned.
*/
static inline bool ether_addr_equal_unaligned(const u8 *addr1, const u8 *addr2)
{
#if defined(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS)
return ether_addr_equal(addr1, addr2);
#else
return memcmp(addr1, addr2, ETH_ALEN) == 0;
#endif
}
/**
* 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
*
* Compare passed address with all addresses of the device. Return true if the
* address if one of the device addresses.
*
* Note that this function calls ether_addr_equal_64bits() so take care of
* the right padding.
*/
static inline bool is_etherdev_addr(const struct net_device *dev,
const u8 addr[6 + 2])
{
struct netdev_hw_addr *ha;
bool res = false;
rcu_read_lock();
for_each_dev_addr(dev, ha) {
res = ether_addr_equal_64bits(addr, ha->addr);
if (res)
break;
}
rcu_read_unlock();
return res;
}
#endif /* __KERNEL__ */
/**
* compare_ether_header - Compare two Ethernet headers
* @a: Pointer to Ethernet header
* @b: Pointer to Ethernet header
*
* Compare two Ethernet headers, returns 0 if equal.
* This assumes that the network header (i.e., IP header) is 4-byte
* aligned OR the platform can handle unaligned access. This is the
* case for all packets coming into netif_receive_skb or similar
* entry points.
*/
static inline unsigned long compare_ether_header(const void *a, const void *b)
{
#if defined(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS) && BITS_PER_LONG == 64
unsigned long fold;
/*
* We want to compare 14 bytes:
* [a0 ... a13] ^ [b0 ... b13]
* Use two long XOR, ORed together, with an overlap of two bytes.
* [a0 a1 a2 a3 a4 a5 a6 a7 ] ^ [b0 b1 b2 b3 b4 b5 b6 b7 ] |
* [a6 a7 a8 a9 a10 a11 a12 a13] ^ [b6 b7 b8 b9 b10 b11 b12 b13]
* This means the [a6 a7] ^ [b6 b7] part is done two times.
*/
fold = *(unsigned long *)a ^ *(unsigned long *)b;
fold |= *(unsigned long *)(a + 6) ^ *(unsigned long *)(b + 6);
return fold;
#else
u32 *a32 = (u32 *)((u8 *)a + 2);
u32 *b32 = (u32 *)((u8 *)b + 2);
return (*(u16 *)a ^ *(u16 *)b) | (a32[0] ^ b32[0]) |
(a32[1] ^ b32[1]) | (a32[2] ^ b32[2]);
#endif
}
/**
* eth_skb_pad - Pad buffer to mininum number of octets for Ethernet frame
* @skb: Buffer to pad
*
* An Ethernet frame should have a minimum size of 60 bytes. This function
* takes short frames and pads them with zeros up to the 60 byte limit.
*/
static inline int eth_skb_pad(struct sk_buff *skb)
{
return skb_put_padto(skb, ETH_ZLEN);
}
#endif /* _LINUX_ETHERDEVICE_H */