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Subject[PATCH net-next v4 07/22] ethtool: netlink bitset handling
Date
Declare attribute type constants and add helper functions to generate and
parse arbitrary length bit sets.

Signed-off-by: Michal Kubecek <mkubecek@suse.cz>
---
Documentation/networking/ethtool-netlink.txt | 63 ++
include/uapi/linux/ethtool_netlink.h | 32 +
net/ethtool/Makefile | 2 +-
net/ethtool/bitset.c | 597 +++++++++++++++++++
net/ethtool/bitset.h | 40 ++
net/ethtool/netlink.h | 9 +
6 files changed, 742 insertions(+), 1 deletion(-)
create mode 100644 net/ethtool/bitset.c
create mode 100644 net/ethtool/bitset.h

diff --git a/Documentation/networking/ethtool-netlink.txt b/Documentation/networking/ethtool-netlink.txt
index 377d64c9b7fa..e97218d820c0 100644
--- a/Documentation/networking/ethtool-netlink.txt
+++ b/Documentation/networking/ethtool-netlink.txt
@@ -60,6 +60,69 @@ replies with one message per network device (only those for which the request
is supported).


+Bit sets
+--------
+
+For short bitmaps of (reasonably) fixed length, standard NLA_BITFIELD32 type
+is used. For arbitrary length bitmaps, ethtool netlink uses a nested attribute
+with contents of one of two forms: compact (two binary bitmaps representing
+bit values and mask of affected bits) and bit-by-bit (list of bits identified
+by either index or name).
+
+Compact form: nested (bitset) atrribute contents:
+
+ ETHA_BITSET_LIST (flag) no mask, only a list
+ ETHA_BITSET_SIZE (u32) number of significant bits
+ ETHA_BITSET_VALUE (binary) bitmap of bit values
+ ETHA_BITSET_MASK (binary) bitmap of valid bits
+
+Value and mask must have length at least ETHA_BITSET_SIZE bits rounded up to
+a multiple of 32 bits. They consist of 32-bit words in host byte order, words
+ordered from least significant to most significant (i.e. the same way as
+bitmaps are passed with ioctl interface).
+
+For compact form, ETHA_BITSET_SIZE and ETHA_BITSET_VALUE are mandatory.
+Similar to BITFIELD32, a compact form bit set requests to set bits in the mask
+to 1 (if the bit is set in value) or 0 (if not) and preserve the rest. If
+ETHA_BITSET_LIST is present, there is no mask and bitset represents a simple
+list of bits.
+
+Kernel bit set length may differ from userspace length if older application is
+used on newer kernel or vice versa. If userspace bitmap is longer, an error is
+issued only if the request actually tries to set values of some bits not
+recognized by kernel.
+
+Bit-by-bit form: nested (bitset) attribute contents:
+
+ ETHA_BITSET_LIST (flag) no mask, only a list
+ ETHA_BITSET_SIZE (u32) number of significant bits (optional)
+ ETHA_BITSET_BITS (nested) array of bits
+ ETHA_BITSET_BIT
+ ETHA_BIT_INDEX (u32) bit index (0 for LSB)
+ ETHA_BIT_NAME (string) bit name
+ ETHA_BIT_VALUE (flag) present if bit is set
+ ETHA_BITSET_BIT
+ ...
+
+Bit size is optional for bit-by-bit form. ETHA_BITSET_BITS nest can only
+contain ETHA_BITS_BIT attributes but there can be an arbitrary number of them.
+A bit may be identified by its index or by its name. When used in requests,
+listed bits are set to 0 or 1 according to ETHA_BIT_VALUE, the rest is
+preserved. A request fails if index exceeds kernel bit length or if name is
+not recognized.
+
+When ETHA_BITSET_LIST flag is present, bitset is interpreted as a simple bit
+list. ETHA_BIT_VALUE attributes are not used in such case. Bit list represents
+a bitmap with listed bits set and the rest zero.
+
+In requests, application can use either form. Form used by kernel in reply is
+determined by a flag in flags field of request header. Semantics of value and
+mask depends on the attribute. General idea is that flags control request
+processing, info_mask control which parts of the information are returned in
+"get" request and index identifies a particular subcommand or an object to
+which the request applies.
+
+
List of message types
---------------------

diff --git a/include/uapi/linux/ethtool_netlink.h b/include/uapi/linux/ethtool_netlink.h
index 59240a2cda56..de18e076ed69 100644
--- a/include/uapi/linux/ethtool_netlink.h
+++ b/include/uapi/linux/ethtool_netlink.h
@@ -29,6 +29,38 @@ enum {
ETHA_DEV_MAX = (__ETHA_DEV_CNT - 1)
};

+/* bit sets */
+
+enum {
+ ETHA_BIT_UNSPEC,
+ ETHA_BIT_INDEX, /* u32 */
+ ETHA_BIT_NAME, /* string */
+ ETHA_BIT_VALUE, /* flag */
+
+ __ETHA_BIT_CNT,
+ ETHA_BIT_MAX = (__ETHA_BIT_CNT - 1)
+};
+
+enum {
+ ETHA_BITS_UNSPEC,
+ ETHA_BITS_BIT,
+
+ __ETHA_BITS_CNT,
+ ETHA_BITS_MAX = (__ETHA_BITS_CNT - 1)
+};
+
+enum {
+ ETHA_BITSET_UNSPEC,
+ ETHA_BITSET_LIST, /* flag */
+ ETHA_BITSET_SIZE, /* u32 */
+ ETHA_BITSET_BITS, /* nest - ETHA_BITS_* */
+ ETHA_BITSET_VALUE, /* binary */
+ ETHA_BITSET_MASK, /* binary */
+
+ __ETHA_BITSET_CNT,
+ ETHA_BITSET_MAX = (__ETHA_BITSET_CNT - 1)
+};
+
/* generic netlink info */
#define ETHTOOL_GENL_NAME "ethtool"
#define ETHTOOL_GENL_VERSION 1
diff --git a/net/ethtool/Makefile b/net/ethtool/Makefile
index f30e0da88be5..482fdb9380fa 100644
--- a/net/ethtool/Makefile
+++ b/net/ethtool/Makefile
@@ -4,4 +4,4 @@ obj-y += ioctl.o

obj-$(CONFIG_ETHTOOL_NETLINK) += ethtool_nl.o

-ethtool_nl-y := netlink.o
+ethtool_nl-y := netlink.o bitset.o
diff --git a/net/ethtool/bitset.c b/net/ethtool/bitset.c
new file mode 100644
index 000000000000..28d27a93e51e
--- /dev/null
+++ b/net/ethtool/bitset.c
@@ -0,0 +1,597 @@
+// SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note
+
+#include <linux/ethtool_netlink.h>
+#include <linux/bitmap.h>
+#include "netlink.h"
+#include "bitset.h"
+
+static bool ethnl_test_bit(const void *val, unsigned int index, bool is_u32)
+{
+ if (!val)
+ return true;
+ else if (is_u32)
+ return ((const u32 *)val)[index / 32] & (1U << (index % 32));
+ else
+ return test_bit(index, val);
+}
+
+static void __bitmap_to_u32(u32 *dst, const void *src, unsigned int size,
+ bool is_u32)
+{
+ unsigned int full_words = size / 32;
+ const u32 *src32 = src;
+
+ if (!is_u32) {
+ bitmap_to_arr32(dst, src, size);
+ return;
+ }
+
+ memcpy(dst, src32, full_words * sizeof(u32));
+ if (size % 32 != 0)
+ dst[full_words] = src32[full_words] & ((1U << (size % 32)) - 1);
+}
+
+/* convert standard kernel bitmap (long sized words) to ethtool one (u32 words)
+ * bitmap_to_arr32() is not guaranteed to do "in place" conversion correctly;
+ * moreover, we can use the fact that the conversion is no-op except for 64-bit
+ * big endian architectures
+ */
+#if BITS_PER_LONG == 64 && defined(__BIG_ENDIAN)
+void ethnl_bitmap_to_u32(unsigned long *bitmap, unsigned int nwords)
+{
+ u32 *dst = (u32 *)bitmap;
+ unsigned int i;
+
+ for (i = 0; i < nwords; i++) {
+ unsigned long tmp = READ_ONCE(bitmap[i]);
+
+ dst[2 * i] = tmp & 0xffffffff;
+ dst[2 * i + 1] = tmp >> 32;
+ }
+}
+#endif
+
+static const char *bit_name(const void *names, bool legacy, unsigned int idx)
+{
+ const char (*const legacy_names)[ETH_GSTRING_LEN] = names;
+ const char *const *simple_names = names;
+
+ return legacy ? legacy_names[idx] : simple_names[idx];
+}
+
+/* calculate size for a bitset attribute
+ * see ethnl_put_bitset() for arguments
+ */
+static int __ethnl_bitset_size(unsigned int size, const void *val,
+ const void *mask, const void *names,
+ unsigned int flags)
+{
+ const bool legacy = flags & ETHNL_BITSET_LEGACY_NAMES;
+ const bool compact = flags & ETHNL_BITSET_COMPACT;
+ const bool is_list = flags & ETHNL_BITSET_LIST;
+ const bool is_u32 = flags & ETHNL_BITSET_U32;
+ unsigned int nwords = DIV_ROUND_UP(size, 32);
+ unsigned int len = 0;
+
+ if (WARN_ON(!compact && !names))
+ return -EINVAL;
+ /* list flag */
+ if (flags & ETHNL_BITSET_LIST)
+ len += nla_total_size(sizeof(u32));
+ /* size */
+ len += nla_total_size(sizeof(u32));
+
+ if (compact) {
+ /* values, mask */
+ len += 2 * nla_total_size(nwords * sizeof(u32));
+ } else {
+ unsigned int bits_len = 0;
+ unsigned int bit_len, i;
+
+ for (i = 0; i < size; i++) {
+ const char *name = bit_name(names, legacy, i) ?: "";
+
+ if ((is_list || mask) &&
+ !ethnl_test_bit(is_list ? val : mask, i, is_u32))
+ continue;
+ /* index */
+ bit_len = nla_total_size(sizeof(u32));
+ /* name */
+ bit_len += ethnl_str_size(name);
+ /* value */
+ if (!is_list && ethnl_test_bit(val, i, is_u32))
+ bit_len += nla_total_size(0);
+
+ /* bit nest */
+ bits_len += nla_total_size(bit_len);
+ }
+ /* bits nest */
+ len += nla_total_size(bits_len);
+ }
+
+ /* outermost nest */
+ return nla_total_size(len);
+}
+
+int ethnl_bitset_size(unsigned int size, const unsigned long *val,
+ const unsigned long *mask, const void *names,
+ unsigned int flags)
+{
+ return __ethnl_bitset_size(size, val, mask, names,
+ flags & ~ETHNL_BITSET_U32);
+}
+
+int ethnl_bitset32_size(unsigned int size, const u32 *val, const u32 *mask,
+ const void *names, unsigned int flags)
+{
+ return __ethnl_bitset_size(size, val, mask, names,
+ flags | ETHNL_BITSET_U32);
+}
+
+/**
+ * __ethnl_put_bitset() - Put a bitset nest into a message
+ * @skb: skb with the message
+ * @attrtype: attribute type for the bitset nest
+ * @size: size of the set in bits
+ * @val: bitset values
+ * @mask: mask of valid bits; NULL is interpreted as "all bits"
+ * @names: bit names (only used for verbose format)
+ * @flags: combination of ETHNL_BITSET_* flags
+ *
+ * This is the actual implementation of putting a bitset nested attribute into
+ * a netlink message but callers are supposed to use either ethnl_put_bitset()
+ * for unsigned long based bitmaps or ethnl_put_bitset32() for u32 based ones.
+ * Cleans the nest up on error.
+ *
+ * Return: 0 on success, error value on error
+ */
+static int __ethnl_put_bitset(struct sk_buff *skb, int attrtype,
+ unsigned int size, const void *val,
+ const void *mask, const void *names,
+ unsigned int flags)
+{
+ const bool legacy = flags & ETHNL_BITSET_LEGACY_NAMES;
+ const bool compact = flags & ETHNL_BITSET_COMPACT;
+ const bool is_list = flags & ETHNL_BITSET_LIST;
+ const bool is_u32 = flags & ETHNL_BITSET_U32;
+ struct nlattr *nest;
+ struct nlattr *attr;
+ int ret;
+
+ if (WARN_ON(!compact && !names))
+ return -EINVAL;
+ nest = ethnl_nest_start(skb, attrtype);
+ if (!nest)
+ return -EMSGSIZE;
+
+ ret = -EMSGSIZE;
+ if (is_list && nla_put_flag(skb, ETHA_BITSET_LIST))
+ goto err;
+ if (nla_put_u32(skb, ETHA_BITSET_SIZE, size))
+ goto err;
+ if (compact) {
+ unsigned int bytesize = DIV_ROUND_UP(size, 32) * sizeof(u32);
+
+ attr = nla_reserve(skb, ETHA_BITSET_VALUE, bytesize);
+ if (!attr)
+ goto err;
+ __bitmap_to_u32(nla_data(attr), val, size, is_u32);
+ if (mask) {
+ attr = nla_reserve(skb, ETHA_BITSET_MASK, bytesize);
+ if (!attr)
+ goto err;
+ __bitmap_to_u32(nla_data(attr), mask, size, is_u32);
+ }
+ } else {
+ struct nlattr *bits;
+ unsigned int i;
+
+ bits = ethnl_nest_start(skb, ETHA_BITSET_BITS);
+ if (!bits)
+ goto err;
+ for (i = 0; i < size; i++) {
+ const char *name = bit_name(names, legacy, i) ?: "";
+
+ if ((is_list || mask) &&
+ !ethnl_test_bit(is_list ? val : mask, i, is_u32))
+ continue;
+ attr = ethnl_nest_start(skb, ETHA_BITS_BIT);
+ if (!attr ||
+ nla_put_u32(skb, ETHA_BIT_INDEX, i) ||
+ nla_put_string(skb, ETHA_BIT_NAME, name))
+ goto err;
+ if (!is_list && ethnl_test_bit(val, i, is_u32) &&
+ nla_put_flag(skb, ETHA_BIT_VALUE))
+ goto err;
+ nla_nest_end(skb, attr);
+ }
+ nla_nest_end(skb, bits);
+ }
+
+ nla_nest_end(skb, nest);
+ return 0;
+err:
+ nla_nest_cancel(skb, nest);
+ return ret;
+}
+
+int ethnl_put_bitset(struct sk_buff *skb, int attrtype, unsigned int size,
+ const unsigned long *val, const unsigned long *mask,
+ const void *names, unsigned int flags)
+{
+ return __ethnl_put_bitset(skb, attrtype, size, val, mask, names,
+ flags & ~ETHNL_BITSET_U32);
+}
+
+int ethnl_put_bitset32(struct sk_buff *skb, int attrtype, unsigned int size,
+ const u32 *val, const u32 *mask, const void *names,
+ unsigned int flags)
+{
+ return __ethnl_put_bitset(skb, attrtype, size, val, mask, names,
+ flags | ETHNL_BITSET_U32);
+}
+
+static const struct nla_policy bitset_policy[ETHA_BITSET_MAX + 1] = {
+ [ETHA_BITSET_UNSPEC] = { .type = NLA_REJECT },
+ [ETHA_BITSET_LIST] = { .type = NLA_FLAG },
+ [ETHA_BITSET_SIZE] = { .type = NLA_U32 },
+ [ETHA_BITSET_BITS] = { .type = NLA_NESTED },
+ [ETHA_BITSET_VALUE] = { .type = NLA_BINARY },
+ [ETHA_BITSET_MASK] = { .type = NLA_BINARY },
+};
+
+static const struct nla_policy bit_policy[ETHA_BIT_MAX + 1] = {
+ [ETHA_BIT_UNSPEC] = { .type = NLA_REJECT },
+ [ETHA_BIT_INDEX] = { .type = NLA_U32 },
+ [ETHA_BIT_NAME] = { .type = NLA_NUL_STRING },
+ [ETHA_BIT_VALUE] = { .type = NLA_FLAG },
+};
+
+static int ethnl_name_to_idx(const void *names, bool legacy,
+ unsigned int n_names, const char *name,
+ unsigned int name_len)
+{
+ unsigned int i;
+
+ for (i = 0; i < n_names; i++) {
+ const char *bname = bit_name(names, legacy, i);
+
+ if (bname && !strncmp(bname, name, name_len) &&
+ strlen(bname) <= name_len)
+ return i;
+ }
+
+ return n_names;
+}
+
+static int ethnl_update_bit(unsigned long *bitmap, unsigned long *bitmask,
+ unsigned int nbits, const struct nlattr *bit_attr,
+ bool is_list, const void *names, bool legacy,
+ struct genl_info *info)
+{
+ struct nlattr *tb[ETHA_BIT_MAX + 1];
+ int ret, idx;
+
+ if (nla_type(bit_attr) != ETHA_BITS_BIT) {
+ ETHNL_SET_ERRMSG(info,
+ "ETHA_BITSET_BITS can contain only ETHA_BITS_BIT");
+ return genl_err_attr(info, -EINVAL, bit_attr);
+ }
+ ret = nla_parse_nested_strict(tb, ETHA_BIT_MAX, bit_attr, bit_policy,
+ info->extack);
+ if (ret < 0)
+ return ret;
+
+ if (tb[ETHA_BIT_INDEX]) {
+ const char *name;
+
+ idx = nla_get_u32(tb[ETHA_BIT_INDEX]);
+ if (idx >= nbits) {
+ ETHNL_SET_ERRMSG(info, "bit index too high");
+ return genl_err_attr(info, -EOPNOTSUPP,
+ tb[ETHA_BIT_INDEX]);
+ }
+ name = bit_name(names, legacy, idx);
+ if (tb[ETHA_BIT_NAME] && name &&
+ strncmp(nla_data(tb[ETHA_BIT_NAME]), name,
+ nla_len(tb[ETHA_BIT_NAME]))) {
+ ETHNL_SET_ERRMSG(info, "bit index and name mismatch");
+ return genl_err_attr(info, -EINVAL, bit_attr);
+ }
+ } else if (tb[ETHA_BIT_NAME]) {
+ idx = ethnl_name_to_idx(names, legacy, nbits,
+ nla_data(tb[ETHA_BIT_NAME]),
+ nla_len(tb[ETHA_BIT_NAME]));
+ if (idx >= nbits) {
+ ETHNL_SET_ERRMSG(info, "bit name not found");
+ return genl_err_attr(info, -EOPNOTSUPP,
+ tb[ETHA_BIT_NAME]);
+ }
+ } else {
+ ETHNL_SET_ERRMSG(info, "neither bit index nor name specified");
+ return genl_err_attr(info, -EINVAL, bit_attr);
+ }
+
+ if (is_list || tb[ETHA_BIT_VALUE])
+ set_bit(idx, bitmap);
+ else
+ clear_bit(idx, bitmap);
+ if (!is_list || bitmask)
+ set_bit(idx, bitmask);
+ return 0;
+}
+
+int ethnl_bitset_is_compact(const struct nlattr *bitset, bool *compact)
+{
+ struct nlattr *tb[ETHA_BITSET_MAX + 1];
+ int ret;
+
+ ret = nla_parse_nested_strict(tb, ETHA_BITSET_MAX, bitset,
+ bitset_policy, NULL);
+ if (ret < 0)
+ return ret;
+
+ if (tb[ETHA_BITSET_BITS]) {
+ if (tb[ETHA_BITSET_VALUE] || tb[ETHA_BITSET_MASK])
+ return -EINVAL;
+ *compact = false;
+ return 0;
+ }
+ if (!tb[ETHA_BITSET_SIZE] || !tb[ETHA_BITSET_VALUE])
+ return -EINVAL;
+
+ *compact = true;
+ return 0;
+}
+
+/* 64-bit long endian is the only case when u32 based bitmap and unsigned long
+ * based bitmap layouts differ
+ */
+#if BITS_PER_LONG == 64 && defined(__BIG_ENDIAN)
+/* dst &= src */
+static void __bitmap_and_u32(unsigned long *dst, const u32 *src,
+ unsigned int nbits)
+{
+ unsigned long op;
+
+ while (nbits >= BITS_PER_LONG) {
+ op = src[0] | ((unsigned long)src[1] << 32);
+ *dst &= op;
+
+ dst++;
+ src += 2;
+ nbits -= BITS_PER_LONG;
+ }
+
+ if (!nbits)
+ return;
+ op = src[0];
+ if (nbits > 32)
+ op |= ((unsigned long)src[1] << 32);
+ *dst = (op & BITMAP_LAST_WORD_MASK(nbits));
+}
+
+/* map1 == map2 */
+static bool __bitmap_equal_u32(const unsigned long *map1, const u32 *map2,
+ unsigned int nbits)
+{
+ unsigned long dword;
+
+ while (nbits >= BITS_PER_LONG) {
+ dword = map2[0] | ((unsigned long)map2[1] << 32);
+ if (*map1 != dword)
+ return false;
+
+ map1++;
+ map2 += 2;
+ nbits -= BITS_PER_LONG;
+ }
+
+ if (!nbits)
+ return true;
+ dword = map2[0];
+ if (nbits > 32)
+ dword |= ((unsigned long)map2[1] << 32);
+ return !((*map1 ^ dword) & BITMAP_LAST_WORD_MASK(nbits));
+}
+#else
+/* On 32-bit and 64-bit LE, unsigned long and u32 bitmap layout is the same
+ * but we must not write past dst buffer if the number of words is odd.
+ */
+static void __bitmap_and_u32(unsigned long *dst, const u32 *src,
+ unsigned int nbits)
+{
+ u32 *dst32 = (u32 *)dst;
+
+ while (nbits >= 32) {
+ *dst32++ &= *src++;
+ nbits -= 32;
+ }
+ if (!nbits)
+ return;
+ *dst32 &= (*src & ((1U << nbits) - 1));
+}
+
+static bool __bitmap_equal_u32(const unsigned long *map1, const u32 *map2,
+ unsigned int nbits)
+{
+ unsigned int full_words = nbits / 32;
+ u32 last_word_mask;
+ u32 *map1_32 = (u32 *)map1;
+
+ if (memcmp(map1, map2, full_words * BITS_PER_BYTE))
+ return false;
+ if (!(nbits % 32))
+ return true;
+ last_word_mask = (1U << (nbits % 32)) - 1;
+ return !((map1_32[full_words] ^ map2[full_words]) & last_word_mask);
+}
+#endif
+
+/* copy unsigned long bitmap to unsigned long or u32 */
+static void __bitmap_to_any(void *dst, const unsigned long *src,
+ unsigned int nbits, bool dst_is_u32)
+{
+ if (dst_is_u32)
+ bitmap_to_arr32(dst, src, nbits);
+ else
+ bitmap_copy(dst, src, nbits);
+}
+
+static bool __bitmap_equal_any(const unsigned long *map1, const void *map2,
+ unsigned int nbits, bool is_u32)
+{
+ if (!is_u32)
+ return bitmap_equal(map1, map2, nbits);
+ else
+ return __bitmap_equal_u32(map1, map2, nbits);
+}
+
+/**
+ * __ethnl_update_bitset() - Apply a bitset nest to a bitmap
+ * @bitmap: bitmap to update
+ * @bitmask: if not, mask from the nest is copied here
+ * @nbits: size of the updated bitmap in bits
+ * @attr: nest attribute to parse and apply
+ * @err: pointer to variable to put error value (or 0 on success) to
+ * @names: array of bit names; may be null for compact format
+ * @legacy: true if @names is ioctl style array of char[32], false if it is
+ * a simple array of (char *) strings
+ * @info: genetlink info (also used for extack error reporting)
+ * @is_u32: true: bitmaps are unsigned long based, false: u32 based bitmaps
+ *
+ * This is the actual implementation of bitset nested attribute parser but
+ * callers are supposed to use ethnl_update_bitset() for unsigned long based
+ * bitmaps or ethnl_update_bitset32() for u32 based ones.
+ *
+ * Return: true if the bitmap contents was modified, false if not
+ */
+static bool __ethnl_update_bitset(void *bitmap, void *bitmask,
+ unsigned int nbits, const struct nlattr *attr,
+ int *err, const void *names, bool legacy,
+ struct genl_info *info, bool is_u32)
+{
+ struct nlattr *tb[ETHA_BITSET_MAX + 1];
+ unsigned int change_bits = 0;
+ unsigned int max_bits = 0;
+ unsigned long *val, *mask;
+ bool mod = false;
+ bool is_list;
+
+ *err = 0;
+ if (!attr)
+ return mod;
+ *err = nla_parse_nested_strict(tb, ETHA_BITSET_MAX, attr, bitset_policy,
+ info->extack);
+ if (*err < 0)
+ return mod;
+ *err = -EINVAL;
+ if (tb[ETHA_BITSET_BITS] &&
+ (tb[ETHA_BITSET_VALUE] || tb[ETHA_BITSET_MASK]))
+ return mod;
+ if (!tb[ETHA_BITSET_BITS] &&
+ (!tb[ETHA_BITSET_SIZE] || !tb[ETHA_BITSET_VALUE]))
+ return mod;
+ is_list = (tb[ETHA_BITSET_LIST] != NULL);
+ if (is_list && tb[ETHA_BITSET_MASK])
+ return mod;
+
+ /* To let new userspace to work with old kernel, we allow bitmaps
+ * from userspace to be longer than kernel ones and only issue an
+ * error if userspace actually tries to change a bit not existing
+ * in kernel.
+ */
+ if (tb[ETHA_BITSET_SIZE])
+ change_bits = nla_get_u32(tb[ETHA_BITSET_SIZE]);
+ max_bits = max_t(unsigned int, nbits, change_bits);
+ mask = bitmap_zalloc(max_bits, GFP_KERNEL);
+ val = bitmap_zalloc(max_bits, GFP_KERNEL);
+
+ if (tb[ETHA_BITSET_BITS]) {
+ struct nlattr *bit_attr;
+ int rem;
+
+ if (is_list)
+ bitmap_fill(mask, nbits);
+ else if (is_u32)
+ bitmap_from_arr32(val, bitmap, nbits);
+ else
+ bitmap_copy(val, bitmap, nbits);
+ nla_for_each_nested(bit_attr, tb[ETHA_BITSET_BITS], rem) {
+ *err = ethnl_update_bit(val, mask, nbits, bit_attr,
+ is_list, names, legacy, info);
+ if (*err < 0)
+ goto out_free;
+ }
+ if (bitmask)
+ __bitmap_to_any(bitmask, mask, nbits, is_u32);
+ } else {
+ unsigned int change_words = DIV_ROUND_UP(change_bits, 32);
+
+ *err = 0;
+ if (change_bits == 0 && tb[ETHA_BITSET_MASK])
+ goto out_free;
+ *err = -EINVAL;
+ if (nla_len(tb[ETHA_BITSET_VALUE]) < change_words * sizeof(u32))
+ goto out_free;
+ if (tb[ETHA_BITSET_MASK] &&
+ nla_len(tb[ETHA_BITSET_MASK]) < change_words * sizeof(u32))
+ goto out_free;
+
+ bitmap_from_arr32(val, nla_data(tb[ETHA_BITSET_VALUE]),
+ change_bits);
+ if (tb[ETHA_BITSET_MASK])
+ bitmap_from_arr32(mask, nla_data(tb[ETHA_BITSET_MASK]),
+ change_bits);
+ else
+ bitmap_fill(mask, nbits);
+
+ if (nbits < change_bits) {
+ unsigned int idx = find_next_bit(mask, max_bits, nbits);
+
+ *err = -EINVAL;
+ if (idx < max_bits)
+ goto out_free;
+ }
+
+ if (bitmask)
+ __bitmap_to_any(bitmask, mask, nbits, is_u32);
+ if (!is_list) {
+ bitmap_and(val, val, mask, nbits);
+ bitmap_complement(mask, mask, nbits);
+ if (is_u32)
+ __bitmap_and_u32(mask, bitmap, nbits);
+ else
+ bitmap_and(mask, mask, bitmap, nbits);
+ bitmap_or(val, val, mask, nbits);
+ }
+ }
+
+ mod = !__bitmap_equal_any(val, bitmap, nbits, is_u32);
+ if (mod)
+ __bitmap_to_any(bitmap, val, nbits, is_u32);
+
+ *err = 0;
+out_free:
+ bitmap_free(val);
+ bitmap_free(mask);
+ return mod;
+}
+
+bool ethnl_update_bitset(unsigned long *bitmap, unsigned long *bitmask,
+ unsigned int nbits, const struct nlattr *attr,
+ int *err, const void *names, bool legacy,
+ struct genl_info *info)
+{
+ return __ethnl_update_bitset(bitmap, bitmask, nbits, attr, err, names,
+ legacy, info, false);
+}
+
+bool ethnl_update_bitset32(u32 *bitmap, u32 *bitmask, unsigned int nbits,
+ const struct nlattr *attr, int *err,
+ const void *names, bool legacy,
+ struct genl_info *info)
+{
+ return __ethnl_update_bitset(bitmap, bitmask, nbits, attr, err, names,
+ legacy, info, true);
+}
diff --git a/net/ethtool/bitset.h b/net/ethtool/bitset.h
new file mode 100644
index 000000000000..761d0c47fe23
--- /dev/null
+++ b/net/ethtool/bitset.h
@@ -0,0 +1,40 @@
+/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
+
+#ifndef _NET_ETHTOOL_BITSET_H
+#define _NET_ETHTOOL_BITSET_H
+
+/* when set, value and mask bitmaps are arrays of u32, when not, arrays of
+ * unsigned long
+ */
+#define ETHNL_BITSET_U32 BIT(0)
+/* generate a compact format bitset */
+#define ETHNL_BITSET_COMPACT BIT(1)
+/* generate a bit list */
+#define ETHNL_BITSET_LIST BIT(2)
+/* when set, names are interpreted as legacy string set (an array of
+ * char[ETH_GSTRING_LEN]), when not, as a simple array of char *
+ */
+#define ETHNL_BITSET_LEGACY_NAMES BIT(3)
+
+int ethnl_bitset_is_compact(const struct nlattr *bitset, bool *compact);
+int ethnl_bitset_size(unsigned int size, const unsigned long *val,
+ const unsigned long *mask, const void *names,
+ unsigned int flags);
+int ethnl_bitset32_size(unsigned int size, const u32 *val, const u32 *mask,
+ const void *names, unsigned int flags);
+int ethnl_put_bitset(struct sk_buff *skb, int attrtype, unsigned int size,
+ const unsigned long *val, const unsigned long *mask,
+ const void *names, unsigned int flags);
+int ethnl_put_bitset32(struct sk_buff *skb, int attrtype, unsigned int size,
+ const u32 *val, const u32 *mask, const void *names,
+ unsigned int flags);
+bool ethnl_update_bitset(unsigned long *bitmap, unsigned long *bitmask,
+ unsigned int nbits, const struct nlattr *attr,
+ int *err, const void *names, bool legacy,
+ struct genl_info *info);
+bool ethnl_update_bitset32(u32 *bitmap, u32 *bitmask, unsigned int nbits,
+ const struct nlattr *attr, int *err,
+ const void *names, bool legacy,
+ struct genl_info *info);
+
+#endif /* _NET_ETHTOOL_BITSET_H */
diff --git a/net/ethtool/netlink.h b/net/ethtool/netlink.h
index db90d95410b1..b8a6cd3dc3e3 100644
--- a/net/ethtool/netlink.h
+++ b/net/ethtool/netlink.h
@@ -20,6 +20,15 @@ struct sk_buff *ethnl_reply_init(size_t payload, struct net_device *dev, u8 cmd,
u16 dev_attrtype, struct genl_info *info,
void **ehdrp);

+#if BITS_PER_LONG == 64 && defined(__BIG_ENDIAN)
+void ethnl_bitmap_to_u32(unsigned long *bitmap, unsigned int nwords);
+#else
+static inline void ethnl_bitmap_to_u32(unsigned long *bitmap,
+ unsigned int nwords)
+{
+}
+#endif
+
static inline int ethnl_str_size(const char *s)
{
return nla_total_size(strlen(s) + 1);
--
2.21.0
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