| /* |
| * NETLINK Netlink attributes |
| * |
| * Authors: Thomas Graf <tgraf@suug.ch> |
| * Alexey Kuznetsov <kuznet@ms2.inr.ac.ru> |
| */ |
| |
| #include <linux/module.h> |
| #include <linux/kernel.h> |
| #include <linux/errno.h> |
| #include <linux/jiffies.h> |
| #include <linux/netdevice.h> |
| #include <linux/skbuff.h> |
| #include <linux/string.h> |
| #include <linux/types.h> |
| #include <net/netlink.h> |
| |
| static u16 nla_attr_minlen[NLA_TYPE_MAX+1] __read_mostly = { |
| [NLA_U8] = sizeof(u8), |
| [NLA_U16] = sizeof(u16), |
| [NLA_U32] = sizeof(u32), |
| [NLA_U64] = sizeof(u64), |
| [NLA_NESTED] = NLA_HDRLEN, |
| }; |
| |
| static int validate_nla(struct nlattr *nla, int maxtype, |
| const struct nla_policy *policy) |
| { |
| const struct nla_policy *pt; |
| int minlen = 0, attrlen = nla_len(nla); |
| |
| if (nla->nla_type <= 0 || nla->nla_type > maxtype) |
| return 0; |
| |
| pt = &policy[nla->nla_type]; |
| |
| BUG_ON(pt->type > NLA_TYPE_MAX); |
| |
| switch (pt->type) { |
| case NLA_FLAG: |
| if (attrlen > 0) |
| return -ERANGE; |
| break; |
| |
| case NLA_NUL_STRING: |
| if (pt->len) |
| minlen = min_t(int, attrlen, pt->len + 1); |
| else |
| minlen = attrlen; |
| |
| if (!minlen || memchr(nla_data(nla), '\0', minlen) == NULL) |
| return -EINVAL; |
| /* fall through */ |
| |
| case NLA_STRING: |
| if (attrlen < 1) |
| return -ERANGE; |
| |
| if (pt->len) { |
| char *buf = nla_data(nla); |
| |
| if (buf[attrlen - 1] == '\0') |
| attrlen--; |
| |
| if (attrlen > pt->len) |
| return -ERANGE; |
| } |
| break; |
| |
| case NLA_BINARY: |
| if (pt->len && attrlen > pt->len) |
| return -ERANGE; |
| break; |
| |
| default: |
| if (pt->len) |
| minlen = pt->len; |
| else if (pt->type != NLA_UNSPEC) |
| minlen = nla_attr_minlen[pt->type]; |
| |
| if (attrlen < minlen) |
| return -ERANGE; |
| } |
| |
| return 0; |
| } |
| |
| /** |
| * nla_validate - Validate a stream of attributes |
| * @head: head of attribute stream |
| * @len: length of attribute stream |
| * @maxtype: maximum attribute type to be expected |
| * @policy: validation policy |
| * |
| * Validates all attributes in the specified attribute stream against the |
| * specified policy. Attributes with a type exceeding maxtype will be |
| * ignored. See documenation of struct nla_policy for more details. |
| * |
| * Returns 0 on success or a negative error code. |
| */ |
| int nla_validate(struct nlattr *head, int len, int maxtype, |
| const struct nla_policy *policy) |
| { |
| struct nlattr *nla; |
| int rem, err; |
| |
| nla_for_each_attr(nla, head, len, rem) { |
| err = validate_nla(nla, maxtype, policy); |
| if (err < 0) |
| goto errout; |
| } |
| |
| err = 0; |
| errout: |
| return err; |
| } |
| |
| /** |
| * nla_parse - Parse a stream of attributes into a tb buffer |
| * @tb: destination array with maxtype+1 elements |
| * @maxtype: maximum attribute type to be expected |
| * @head: head of attribute stream |
| * @len: length of attribute stream |
| * |
| * Parses a stream of attributes and stores a pointer to each attribute in |
| * the tb array accessable via the attribute type. Attributes with a type |
| * exceeding maxtype will be silently ignored for backwards compatibility |
| * reasons. policy may be set to NULL if no validation is required. |
| * |
| * Returns 0 on success or a negative error code. |
| */ |
| int nla_parse(struct nlattr *tb[], int maxtype, struct nlattr *head, int len, |
| const struct nla_policy *policy) |
| { |
| struct nlattr *nla; |
| int rem, err; |
| |
| memset(tb, 0, sizeof(struct nlattr *) * (maxtype + 1)); |
| |
| nla_for_each_attr(nla, head, len, rem) { |
| u16 type = nla->nla_type; |
| |
| if (type > 0 && type <= maxtype) { |
| if (policy) { |
| err = validate_nla(nla, maxtype, policy); |
| if (err < 0) |
| goto errout; |
| } |
| |
| tb[type] = nla; |
| } |
| } |
| |
| if (unlikely(rem > 0)) |
| printk(KERN_WARNING "netlink: %d bytes leftover after parsing " |
| "attributes.\n", rem); |
| |
| err = 0; |
| errout: |
| return err; |
| } |
| |
| /** |
| * nla_find - Find a specific attribute in a stream of attributes |
| * @head: head of attribute stream |
| * @len: length of attribute stream |
| * @attrtype: type of attribute to look for |
| * |
| * Returns the first attribute in the stream matching the specified type. |
| */ |
| struct nlattr *nla_find(struct nlattr *head, int len, int attrtype) |
| { |
| struct nlattr *nla; |
| int rem; |
| |
| nla_for_each_attr(nla, head, len, rem) |
| if (nla->nla_type == attrtype) |
| return nla; |
| |
| return NULL; |
| } |
| |
| /** |
| * nla_strlcpy - Copy string attribute payload into a sized buffer |
| * @dst: where to copy the string to |
| * @src: attribute to copy the string from |
| * @dstsize: size of destination buffer |
| * |
| * Copies at most dstsize - 1 bytes into the destination buffer. |
| * The result is always a valid NUL-terminated string. Unlike |
| * strlcpy the destination buffer is always padded out. |
| * |
| * Returns the length of the source buffer. |
| */ |
| size_t nla_strlcpy(char *dst, const struct nlattr *nla, size_t dstsize) |
| { |
| size_t srclen = nla_len(nla); |
| char *src = nla_data(nla); |
| |
| if (srclen > 0 && src[srclen - 1] == '\0') |
| srclen--; |
| |
| if (dstsize > 0) { |
| size_t len = (srclen >= dstsize) ? dstsize - 1 : srclen; |
| |
| memset(dst, 0, dstsize); |
| memcpy(dst, src, len); |
| } |
| |
| return srclen; |
| } |
| |
| /** |
| * nla_memcpy - Copy a netlink attribute into another memory area |
| * @dest: where to copy to memcpy |
| * @src: netlink attribute to copy from |
| * @count: size of the destination area |
| * |
| * Note: The number of bytes copied is limited by the length of |
| * attribute's payload. memcpy |
| * |
| * Returns the number of bytes copied. |
| */ |
| int nla_memcpy(void *dest, struct nlattr *src, int count) |
| { |
| int minlen = min_t(int, count, nla_len(src)); |
| |
| memcpy(dest, nla_data(src), minlen); |
| |
| return minlen; |
| } |
| |
| /** |
| * nla_memcmp - Compare an attribute with sized memory area |
| * @nla: netlink attribute |
| * @data: memory area |
| * @size: size of memory area |
| */ |
| int nla_memcmp(const struct nlattr *nla, const void *data, |
| size_t size) |
| { |
| int d = nla_len(nla) - size; |
| |
| if (d == 0) |
| d = memcmp(nla_data(nla), data, size); |
| |
| return d; |
| } |
| |
| /** |
| * nla_strcmp - Compare a string attribute against a string |
| * @nla: netlink string attribute |
| * @str: another string |
| */ |
| int nla_strcmp(const struct nlattr *nla, const char *str) |
| { |
| int len = strlen(str) + 1; |
| int d = nla_len(nla) - len; |
| |
| if (d == 0) |
| d = memcmp(nla_data(nla), str, len); |
| |
| return d; |
| } |
| |
| /** |
| * __nla_reserve - reserve room for attribute on the skb |
| * @skb: socket buffer to reserve room on |
| * @attrtype: attribute type |
| * @attrlen: length of attribute payload |
| * |
| * Adds a netlink attribute header to a socket buffer and reserves |
| * room for the payload but does not copy it. |
| * |
| * The caller is responsible to ensure that the skb provides enough |
| * tailroom for the attribute header and payload. |
| */ |
| struct nlattr *__nla_reserve(struct sk_buff *skb, int attrtype, int attrlen) |
| { |
| struct nlattr *nla; |
| |
| nla = (struct nlattr *) skb_put(skb, nla_total_size(attrlen)); |
| nla->nla_type = attrtype; |
| nla->nla_len = nla_attr_size(attrlen); |
| |
| memset((unsigned char *) nla + nla->nla_len, 0, nla_padlen(attrlen)); |
| |
| return nla; |
| } |
| |
| /** |
| * __nla_reserve_nohdr - reserve room for attribute without header |
| * @skb: socket buffer to reserve room on |
| * @attrlen: length of attribute payload |
| * |
| * Reserves room for attribute payload without a header. |
| * |
| * The caller is responsible to ensure that the skb provides enough |
| * tailroom for the payload. |
| */ |
| void *__nla_reserve_nohdr(struct sk_buff *skb, int attrlen) |
| { |
| void *start; |
| |
| start = skb_put(skb, NLA_ALIGN(attrlen)); |
| memset(start, 0, NLA_ALIGN(attrlen)); |
| |
| return start; |
| } |
| |
| /** |
| * nla_reserve - reserve room for attribute on the skb |
| * @skb: socket buffer to reserve room on |
| * @attrtype: attribute type |
| * @attrlen: length of attribute payload |
| * |
| * Adds a netlink attribute header to a socket buffer and reserves |
| * room for the payload but does not copy it. |
| * |
| * Returns NULL if the tailroom of the skb is insufficient to store |
| * the attribute header and payload. |
| */ |
| struct nlattr *nla_reserve(struct sk_buff *skb, int attrtype, int attrlen) |
| { |
| if (unlikely(skb_tailroom(skb) < nla_total_size(attrlen))) |
| return NULL; |
| |
| return __nla_reserve(skb, attrtype, attrlen); |
| } |
| |
| /** |
| * nla_reserve - reserve room for attribute without header |
| * @skb: socket buffer to reserve room on |
| * @len: length of attribute payload |
| * |
| * Reserves room for attribute payload without a header. |
| * |
| * Returns NULL if the tailroom of the skb is insufficient to store |
| * the attribute payload. |
| */ |
| void *nla_reserve_nohdr(struct sk_buff *skb, int attrlen) |
| { |
| if (unlikely(skb_tailroom(skb) < NLA_ALIGN(attrlen))) |
| return NULL; |
| |
| return __nla_reserve_nohdr(skb, attrlen); |
| } |
| |
| /** |
| * __nla_put - Add a netlink attribute to a socket buffer |
| * @skb: socket buffer to add attribute to |
| * @attrtype: attribute type |
| * @attrlen: length of attribute payload |
| * @data: head of attribute payload |
| * |
| * The caller is responsible to ensure that the skb provides enough |
| * tailroom for the attribute header and payload. |
| */ |
| void __nla_put(struct sk_buff *skb, int attrtype, int attrlen, |
| const void *data) |
| { |
| struct nlattr *nla; |
| |
| nla = __nla_reserve(skb, attrtype, attrlen); |
| memcpy(nla_data(nla), data, attrlen); |
| } |
| |
| /** |
| * __nla_put_nohdr - Add a netlink attribute without header |
| * @skb: socket buffer to add attribute to |
| * @attrlen: length of attribute payload |
| * @data: head of attribute payload |
| * |
| * The caller is responsible to ensure that the skb provides enough |
| * tailroom for the attribute payload. |
| */ |
| void __nla_put_nohdr(struct sk_buff *skb, int attrlen, const void *data) |
| { |
| void *start; |
| |
| start = __nla_reserve_nohdr(skb, attrlen); |
| memcpy(start, data, attrlen); |
| } |
| |
| /** |
| * nla_put - Add a netlink attribute to a socket buffer |
| * @skb: socket buffer to add attribute to |
| * @attrtype: attribute type |
| * @attrlen: length of attribute payload |
| * @data: head of attribute payload |
| * |
| * Returns -1 if the tailroom of the skb is insufficient to store |
| * the attribute header and payload. |
| */ |
| int nla_put(struct sk_buff *skb, int attrtype, int attrlen, const void *data) |
| { |
| if (unlikely(skb_tailroom(skb) < nla_total_size(attrlen))) |
| return -1; |
| |
| __nla_put(skb, attrtype, attrlen, data); |
| return 0; |
| } |
| |
| /** |
| * nla_put_nohdr - Add a netlink attribute without header |
| * @skb: socket buffer to add attribute to |
| * @attrlen: length of attribute payload |
| * @data: head of attribute payload |
| * |
| * Returns -1 if the tailroom of the skb is insufficient to store |
| * the attribute payload. |
| */ |
| int nla_put_nohdr(struct sk_buff *skb, int attrlen, const void *data) |
| { |
| if (unlikely(skb_tailroom(skb) < NLA_ALIGN(attrlen))) |
| return -1; |
| |
| __nla_put_nohdr(skb, attrlen, data); |
| return 0; |
| } |
| |
| EXPORT_SYMBOL(nla_validate); |
| EXPORT_SYMBOL(nla_parse); |
| EXPORT_SYMBOL(nla_find); |
| EXPORT_SYMBOL(nla_strlcpy); |
| EXPORT_SYMBOL(__nla_reserve); |
| EXPORT_SYMBOL(__nla_reserve_nohdr); |
| EXPORT_SYMBOL(nla_reserve); |
| EXPORT_SYMBOL(nla_reserve_nohdr); |
| EXPORT_SYMBOL(__nla_put); |
| EXPORT_SYMBOL(__nla_put_nohdr); |
| EXPORT_SYMBOL(nla_put); |
| EXPORT_SYMBOL(nla_put_nohdr); |
| EXPORT_SYMBOL(nla_memcpy); |
| EXPORT_SYMBOL(nla_memcmp); |
| EXPORT_SYMBOL(nla_strcmp); |