/* * NETLINK Netlink attributes * * Authors: Thomas Graf <tgraf@suug.ch> * Alexey Kuznetsov <kuznet@ms2.inr.ac.ru> */ #include <linux/export.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 const u16 nla_attr_minlen[NLA_TYPE_MAX+1] = { [NLA_U8] = sizeof(u8), [NLA_U16] = sizeof(u16), [NLA_U32] = sizeof(u32), [NLA_U64] = sizeof(u64), [NLA_MSECS] = sizeof(u64), [NLA_NESTED] = NLA_HDRLEN, [NLA_S8] = sizeof(s8), [NLA_S16] = sizeof(s16), [NLA_S32] = sizeof(s32), [NLA_S64] = sizeof(s64),}; static int validate_nla(const struct nlattr *nla, int maxtype, const struct nla_policy *policy){ const struct nla_policy *pt; int minlen = 0, attrlen = nla_len(nla), type = nla_type(nla); if (type <= 0 || type > maxtype) return 0; pt = &policy[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; case NLA_NESTED_COMPAT: if (attrlen < pt->len) return -ERANGE; if (attrlen < NLA_ALIGN(pt->len)) break; if (attrlen < NLA_ALIGN(pt->len) + NLA_HDRLEN) return -ERANGE; nla = nla_data(nla) + NLA_ALIGN(pt->len); if (attrlen < NLA_ALIGN(pt->len) + NLA_HDRLEN + nla_len(nla)) return -ERANGE; break; case NLA_NESTED: /* a nested attributes is allowed to be empty; if its not, * it must have a size of at least NLA_HDRLEN. */ if (attrlen == 0) 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(const struct nlattr *head, int len, int maxtype, const struct nla_policy *policy){ const 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_policy_len - Determin the max. length of a policy * @policy: policy to use * @n: number of policies * * Determines the max. length of the policy. It is currently used * to allocated Netlink buffers roughly the size of the actual * message. * * Returns 0 on success or a negative error code. */intnla_policy_len(const struct nla_policy *p, int n){ int i, len = 0; for (i = 0; i < n; i++, p++) { if (p->len) len += nla_total_size(p->len); else if (nla_attr_minlen[p->type]) len += nla_total_size(nla_attr_minlen[p->type]); } return len;} /** * 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 * @policy: validation policy * * Parses a stream of attributes and stores a pointer to each attribute in * the tb array accessible 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, const struct nlattr *head, int len, const struct nla_policy *policy){ const 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_type(nla); if (type > 0 && type <= maxtype) { if (policy) { err = validate_nla(nla, maxtype, policy); if (err < 0) goto errout; } tb[type] = (struct nlattr *)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(const struct nlattr *head, int len, int attrtype){ const struct nlattr *nla; int rem; nla_for_each_attr(nla, head, len, rem) if (nla_type(nla) == attrtype) return (struct nlattr *)nla; return NULL;} /** * nla_strlcpy - Copy string attribute payload into a sized buffer * @dst: where to copy the string to * @nla: 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, const 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;} #ifdef CONFIG_NET/** * __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;}EXPORT_SYMBOL(__nla_reserve); /** * __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;}EXPORT_SYMBOL(__nla_reserve_nohdr); /** * 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);}EXPORT_SYMBOL(nla_reserve); /** * 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. * * 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);}EXPORT_SYMBOL(nla_reserve_nohdr); /** * __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);}EXPORT_SYMBOL(__nla_put); /** * __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);}EXPORT_SYMBOL(__nla_put_nohdr); /** * 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 -EMSGSIZE 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 -EMSGSIZE; __nla_put(skb, attrtype, attrlen, data); return 0;}EXPORT_SYMBOL(nla_put); /** * 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 -EMSGSIZE 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 -EMSGSIZE; __nla_put_nohdr(skb, attrlen, data); return 0;}EXPORT_SYMBOL(nla_put_nohdr); /** * nla_append - Add a netlink attribute without header or padding * @skb: socket buffer to add attribute to * @attrlen: length of attribute payload * @data: head of attribute payload * * Returns -EMSGSIZE if the tailroom of the skb is insufficient to store * the attribute payload. */int nla_append(struct sk_buff *skb, int attrlen, const void *data){ if (unlikely(skb_tailroom(skb) < NLA_ALIGN(attrlen))) return -EMSGSIZE; memcpy(skb_put(skb, attrlen), data, attrlen); return 0;}EXPORT_SYMBOL(nla_append);#endif EXPORT_SYMBOL(nla_validate);Lines 1–500 of 507. 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/* * NETLINK Netlink attributes * * Authors: Thomas Graf <tgraf@suug.ch> * Alexey Kuznetsov <kuznet@ms2.inr.ac.ru> */ #include <linux/export.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 const u16 nla_attr_minlen[NLA_TYPE_MAX+1] = { [NLA_U8] = sizeof(u8), [NLA_U16] = sizeof(u16), [NLA_U32] = sizeof(u32), [NLA_U64] = sizeof(u64), [NLA_MSECS] = sizeof(u64), [NLA_NESTED] = NLA_HDRLEN, [NLA_S8] = sizeof(s8), [NLA_S16] = sizeof(s16), [NLA_S32] = sizeof(s32), [NLA_S64] = sizeof(s64), }; static int validate_nla(const struct nlattr *nla, int maxtype, const struct nla_policy *policy) { const struct nla_policy *pt; int minlen = 0, attrlen = nla_len(nla), type = nla_type(nla); if (type <= 0 || type > maxtype) return 0; pt = &policy[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; case NLA_NESTED_COMPAT: if (attrlen < pt->len) return -ERANGE; if (attrlen < NLA_ALIGN(pt->len)) break; if (attrlen < NLA_ALIGN(pt->len) + NLA_HDRLEN) return -ERANGE; nla = nla_data(nla) + NLA_ALIGN(pt->len); if (attrlen < NLA_ALIGN(pt->len) + NLA_HDRLEN + nla_len(nla)) return -ERANGE; break; case NLA_NESTED: /* a nested attributes is allowed to be empty; if its not, * it must have a size of at least NLA_HDRLEN. */ if (attrlen == 0) 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(const struct nlattr *head, int len, int maxtype, const struct nla_policy *policy) { const 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_policy_len - Determin the max. length of a policy * @policy: policy to use * @n: number of policies * * Determines the max. length of the policy. It is currently used * to allocated Netlink buffers roughly the size of the actual * message. * * Returns 0 on success or a negative error code. */ int nla_policy_len(const struct nla_policy *p, int n) { int i, len = 0; for (i = 0; i < n; i++, p++) { if (p->len) len += nla_total_size(p->len); else if (nla_attr_minlen[p->type]) len += nla_total_size(nla_attr_minlen[p->type]); } return len; } /** * 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 * @policy: validation policy * * Parses a stream of attributes and stores a pointer to each attribute in * the tb array accessible 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, const struct nlattr *head, int len, const struct nla_policy *policy) { const 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_type(nla); if (type > 0 && type <= maxtype) { if (policy) { err = validate_nla(nla, maxtype, policy); if (err < 0) goto errout; } tb[type] = (struct nlattr *)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(const struct nlattr *head, int len, int attrtype) { const struct nlattr *nla; int rem; nla_for_each_attr(nla, head, len, rem) if (nla_type(nla) == attrtype) return (struct nlattr *)nla; return NULL; } /** * nla_strlcpy - Copy string attribute payload into a sized buffer * @dst: where to copy the string to * @nla: 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, const 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; } #ifdef CONFIG_NET /** * __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; } EXPORT_SYMBOL(__nla_reserve); /** * __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; } EXPORT_SYMBOL(__nla_reserve_nohdr); /** * 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); } EXPORT_SYMBOL(nla_reserve); /** * 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. * * 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); } EXPORT_SYMBOL(nla_reserve_nohdr); /** * __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); } EXPORT_SYMBOL(__nla_put); /** * __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); } EXPORT_SYMBOL(__nla_put_nohdr); /** * 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 -EMSGSIZE 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 -EMSGSIZE; __nla_put(skb, attrtype, attrlen, data); return 0; } EXPORT_SYMBOL(nla_put); /** * 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 -EMSGSIZE 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 -EMSGSIZE; __nla_put_nohdr(skb, attrlen, data); return 0; } EXPORT_SYMBOL(nla_put_nohdr); /** * nla_append - Add a netlink attribute without header or padding * @skb: socket buffer to add attribute to * @attrlen: length of attribute payload * @data: head of attribute payload * * Returns -EMSGSIZE if the tailroom of the skb is insufficient to store * the attribute payload. */ int nla_append(struct sk_buff *skb, int attrlen, const void *data) { if (unlikely(skb_tailroom(skb) < NLA_ALIGN(attrlen))) return -EMSGSIZE; memcpy(skb_put(skb, attrlen), data, attrlen); return 0; } EXPORT_SYMBOL(nla_append); #endif EXPORT_SYMBOL(nla_validate);