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-rw-r--r--include/linux/netlink.h24
-rw-r--r--include/net/netlink.h877
-rw-r--r--net/netlink/Makefile2
-rw-r--r--net/netlink/attr.c328
4 files changed, 1229 insertions, 2 deletions
diff --git a/include/linux/netlink.h b/include/linux/netlink.h
index ba25ca8..6a2ccf7 100644
--- a/include/linux/netlink.h
+++ b/include/linux/netlink.h
@@ -71,7 +71,8 @@ struct nlmsghdr
#define NLMSG_ALIGNTO 4
#define NLMSG_ALIGN(len) ( ((len)+NLMSG_ALIGNTO-1) & ~(NLMSG_ALIGNTO-1) )
-#define NLMSG_LENGTH(len) ((len)+NLMSG_ALIGN(sizeof(struct nlmsghdr)))
+#define NLMSG_HDRLEN ((int) NLMSG_ALIGN(sizeof(struct nlmsghdr)))
+#define NLMSG_LENGTH(len) ((len)+NLMSG_ALIGN(NLMSG_HDRLEN))
#define NLMSG_SPACE(len) NLMSG_ALIGN(NLMSG_LENGTH(len))
#define NLMSG_DATA(nlh) ((void*)(((char*)nlh) + NLMSG_LENGTH(0)))
#define NLMSG_NEXT(nlh,len) ((len) -= NLMSG_ALIGN((nlh)->nlmsg_len), \
@@ -86,6 +87,8 @@ struct nlmsghdr
#define NLMSG_DONE 0x3 /* End of a dump */
#define NLMSG_OVERRUN 0x4 /* Data lost */
+#define NLMSG_MIN_TYPE 0x10 /* < 0x10: reserved control messages */
+
struct nlmsgerr
{
int error;
@@ -108,6 +111,25 @@ enum {
NETLINK_CONNECTED,
};
+/*
+ * <------- NLA_HDRLEN ------> <-- NLA_ALIGN(payload)-->
+ * +---------------------+- - -+- - - - - - - - - -+- - -+
+ * | Header | Pad | Payload | Pad |
+ * | (struct nlattr) | ing | | ing |
+ * +---------------------+- - -+- - - - - - - - - -+- - -+
+ * <-------------- nlattr->nla_len -------------->
+ */
+
+struct nlattr
+{
+ __u16 nla_len;
+ __u16 nla_type;
+};
+
+#define NLA_ALIGNTO 4
+#define NLA_ALIGN(len) (((len) + NLA_ALIGNTO - 1) & ~(NLA_ALIGNTO - 1))
+#define NLA_HDRLEN ((int) NLA_ALIGN(sizeof(struct nlattr)))
+
#ifdef __KERNEL__
#include <linux/capability.h>
diff --git a/include/net/netlink.h b/include/net/netlink.h
new file mode 100644
index 0000000..c99e22d
--- /dev/null
+++ b/include/net/netlink.h
@@ -0,0 +1,877 @@
+#ifndef __NET_NETLINK_H
+#define __NET_NETLINK_H
+
+#include <linux/types.h>
+#include <linux/netlink.h>
+
+/* ========================================================================
+ * Netlink Messages and Attributes Interface (As Seen On TV)
+ * ------------------------------------------------------------------------
+ * Messages Interface
+ * ------------------------------------------------------------------------
+ *
+ * Message Format:
+ * <--- nlmsg_total_size(payload) --->
+ * <-- nlmsg_msg_size(payload) ->
+ * +----------+- - -+-------------+- - -+-------- - -
+ * | nlmsghdr | Pad | Payload | Pad | nlmsghdr
+ * +----------+- - -+-------------+- - -+-------- - -
+ * nlmsg_data(nlh)---^ ^
+ * nlmsg_next(nlh)-----------------------+
+ *
+ * Payload Format:
+ * <---------------------- nlmsg_len(nlh) --------------------->
+ * <------ hdrlen ------> <- nlmsg_attrlen(nlh, hdrlen) ->
+ * +----------------------+- - -+--------------------------------+
+ * | Family Header | Pad | Attributes |
+ * +----------------------+- - -+--------------------------------+
+ * nlmsg_attrdata(nlh, hdrlen)---^
+ *
+ * Data Structures:
+ * struct nlmsghdr netlink message header
+ *
+ * Message Construction:
+ * nlmsg_new() create a new netlink message
+ * nlmsg_put() add a netlink message to an skb
+ * nlmsg_put_answer() callback based nlmsg_put()
+ * nlmsg_end() finanlize netlink message
+ * nlmsg_cancel() cancel message construction
+ * nlmsg_free() free a netlink message
+ *
+ * Message Sending:
+ * nlmsg_multicast() multicast message to several groups
+ * nlmsg_unicast() unicast a message to a single socket
+ *
+ * Message Length Calculations:
+ * nlmsg_msg_size(payload) length of message w/o padding
+ * nlmsg_total_size(payload) length of message w/ padding
+ * nlmsg_padlen(payload) length of padding at tail
+ *
+ * Message Payload Access:
+ * nlmsg_data(nlh) head of message payload
+ * nlmsg_len(nlh) length of message payload
+ * nlmsg_attrdata(nlh, hdrlen) head of attributes data
+ * nlmsg_attrlen(nlh, hdrlen) length of attributes data
+ *
+ * Message Parsing:
+ * nlmsg_ok(nlh, remaining) does nlh fit into remaining bytes?
+ * nlmsg_next(nlh, remaining) get next netlink message
+ * nlmsg_parse() parse attributes of a message
+ * nlmsg_find_attr() find an attribute in a message
+ * nlmsg_for_each_msg() loop over all messages
+ * nlmsg_validate() validate netlink message incl. attrs
+ * nlmsg_for_each_attr() loop over all attributes
+ *
+ * ------------------------------------------------------------------------
+ * Attributes Interface
+ * ------------------------------------------------------------------------
+ *
+ * Attribute Format:
+ * <------- nla_total_size(payload) ------->
+ * <---- nla_attr_size(payload) ----->
+ * +----------+- - -+- - - - - - - - - +- - -+-------- - -
+ * | Header | Pad | Payload | Pad | Header
+ * +----------+- - -+- - - - - - - - - +- - -+-------- - -
+ * <- nla_len(nla) -> ^
+ * nla_data(nla)----^ |
+ * nla_next(nla)-----------------------------'
+ *
+ * Data Structures:
+ * struct nlattr netlink attribtue header
+ *
+ * Attribute Construction:
+ * nla_reserve(skb, type, len) reserve skb tailroom for an attribute
+ * nla_put(skb, type, len, data) add attribute to skb
+ *
+ * Attribute Construction for Basic Types:
+ * nla_put_u8(skb, type, value) add u8 attribute to skb
+ * nla_put_u16(skb, type, value) add u16 attribute to skb
+ * nla_put_u32(skb, type, value) add u32 attribute to skb
+ * nla_put_u64(skb, type, value) add u64 attribute to skb
+ * nla_put_string(skb, type, str) add string attribute to skb
+ * nla_put_flag(skb, type) add flag attribute to skb
+ * nla_put_msecs(skb, type, jiffies) add msecs attribute to skb
+ *
+ * Exceptions Based Attribute Construction:
+ * NLA_PUT(skb, type, len, data) add attribute to skb
+ * NLA_PUT_U8(skb, type, value) add u8 attribute to skb
+ * NLA_PUT_U16(skb, type, value) add u16 attribute to skb
+ * NLA_PUT_U32(skb, type, value) add u32 attribute to skb
+ * NLA_PUT_U64(skb, type, value) add u64 attribute to skb
+ * NLA_PUT_STRING(skb, type, str) add string attribute to skb
+ * NLA_PUT_FLAG(skb, type) add flag attribute to skb
+ * NLA_PUT_MSECS(skb, type, jiffies) add msecs attribute to skb
+ *
+ * The meaning of these functions is equal to their lower case
+ * variants but they jump to the label nla_put_failure in case
+ * of a failure.
+ *
+ * Nested Attributes Construction:
+ * nla_nest_start(skb, type) start a nested attribute
+ * nla_nest_end(skb, nla) finalize a nested attribute
+ * nla_nest_cancel(skb, nla) cancel nested attribute construction
+ *
+ * Attribute Length Calculations:
+ * nla_attr_size(payload) length of attribute w/o padding
+ * nla_total_size(payload) length of attribute w/ padding
+ * nla_padlen(payload) length of padding
+ *
+ * Attribute Payload Access:
+ * nla_data(nla) head of attribute payload
+ * nla_len(nla) length of attribute payload
+ *
+ * Attribute Payload Access for Basic Types:
+ * nla_get_u8(nla) get payload for a u8 attribute
+ * nla_get_u16(nla) get payload for a u16 attribute
+ * nla_get_u32(nla) get payload for a u32 attribute
+ * nla_get_u64(nla) get payload for a u64 attribute
+ * nla_get_flag(nla) return 1 if flag is true
+ * nla_get_msecs(nla) get payload for a msecs attribute
+ *
+ * Attribute Misc:
+ * nla_memcpy(dest, nla, count) copy attribute into memory
+ * nla_memcmp(nla, data, size) compare attribute with memory area
+ * nla_strlcpy(dst, nla, size) copy attribute to a sized string
+ * nla_strcmp(nla, str) compare attribute with string
+ *
+ * Attribute Parsing:
+ * nla_ok(nla, remaining) does nla fit into remaining bytes?
+ * nla_next(nla, remaining) get next netlink attribute
+ * nla_validate() validate a stream of attributes
+ * nla_find() find attribute in stream of attributes
+ * nla_parse() parse and validate stream of attrs
+ * nla_parse_nested() parse nested attribuets
+ * nla_for_each_attr() loop over all attributes
+ *=========================================================================
+ */
+
+ /**
+ * Standard attribute types to specify validation policy
+ */
+enum {
+ NLA_UNSPEC,
+ NLA_U8,
+ NLA_U16,
+ NLA_U32,
+ NLA_U64,
+ NLA_STRING,
+ NLA_FLAG,
+ NLA_MSECS,
+ NLA_NESTED,
+ __NLA_TYPE_MAX,
+};
+
+#define NLA_TYPE_MAX (__NLA_TYPE_MAX - 1)
+
+/**
+ * struct nla_policy - attribute validation policy
+ * @type: Type of attribute or NLA_UNSPEC
+ * @minlen: Minimal length of payload required to be available
+ *
+ * Policies are defined as arrays of this struct, the array must be
+ * accessible by attribute type up to the highest identifier to be expected.
+ *
+ * Example:
+ * static struct nla_policy my_policy[ATTR_MAX+1] __read_mostly = {
+ * [ATTR_FOO] = { .type = NLA_U16 },
+ * [ATTR_BAR] = { .type = NLA_STRING },
+ * [ATTR_BAZ] = { .minlen = sizeof(struct mystruct) },
+ * };
+ */
+struct nla_policy {
+ u16 type;
+ u16 minlen;
+};
+
+extern int nla_validate(struct nlattr *head, int len, int maxtype,
+ struct nla_policy *policy);
+extern int nla_parse(struct nlattr *tb[], int maxtype,
+ struct nlattr *head, int len,
+ struct nla_policy *policy);
+extern struct nlattr * nla_find(struct nlattr *head, int len, int attrtype);
+extern size_t nla_strlcpy(char *dst, const struct nlattr *nla,
+ size_t dstsize);
+extern int nla_memcpy(void *dest, struct nlattr *src, int count);
+extern int nla_memcmp(const struct nlattr *nla, const void *data,
+ size_t size);
+extern int nla_strcmp(const struct nlattr *nla, const char *str);
+extern struct nlattr * __nla_reserve(struct sk_buff *skb, int attrtype,
+ int attrlen);
+extern struct nlattr * nla_reserve(struct sk_buff *skb, int attrtype,
+ int attrlen);
+extern void __nla_put(struct sk_buff *skb, int attrtype,
+ int attrlen, const void *data);
+extern int nla_put(struct sk_buff *skb, int attrtype,
+ int attrlen, const void *data);
+
+/**************************************************************************
+ * Netlink Messages
+ **************************************************************************/
+
+/**
+ * nlmsg_msg_size - length of netlink message not including padding
+ * @payload: length of message payload
+ */
+static inline int nlmsg_msg_size(int payload)
+{
+ return NLMSG_HDRLEN + payload;
+}
+
+/**
+ * nlmsg_total_size - length of netlink message including padding
+ * @payload: length of message payload
+ */
+static inline int nlmsg_total_size(int payload)
+{
+ return NLMSG_ALIGN(nlmsg_msg_size(payload));
+}
+
+/**
+ * nlmsg_padlen - length of padding at the message's tail
+ * @payload: length of message payload
+ */
+static inline int nlmsg_padlen(int payload)
+{
+ return nlmsg_total_size(payload) - nlmsg_msg_size(payload);
+}
+
+/**
+ * nlmsg_data - head of message payload
+ * @nlh: netlink messsage header
+ */
+static inline void *nlmsg_data(const struct nlmsghdr *nlh)
+{
+ return (unsigned char *) nlh + NLMSG_HDRLEN;
+}
+
+/**
+ * nlmsg_len - length of message payload
+ * @nlh: netlink message header
+ */
+static inline int nlmsg_len(const struct nlmsghdr *nlh)
+{
+ return nlh->nlmsg_len - NLMSG_HDRLEN;
+}
+
+/**
+ * nlmsg_attrdata - head of attributes data
+ * @nlh: netlink message header
+ * @hdrlen: length of family specific header
+ */
+static inline struct nlattr *nlmsg_attrdata(const struct nlmsghdr *nlh,
+ int hdrlen)
+{
+ unsigned char *data = nlmsg_data(nlh);
+ return (struct nlattr *) (data + NLMSG_ALIGN(hdrlen));
+}
+
+/**
+ * nlmsg_attrlen - length of attributes data
+ * @nlh: netlink message header
+ * @hdrlen: length of family specific header
+ */
+static inline int nlmsg_attrlen(const struct nlmsghdr *nlh, int hdrlen)
+{
+ return nlmsg_len(nlh) - NLMSG_ALIGN(hdrlen);
+}
+
+/**
+ * nlmsg_ok - check if the netlink message fits into the remaining bytes
+ * @nlh: netlink message header
+ * @remaining: number of bytes remaining in message stream
+ */
+static inline int nlmsg_ok(const struct nlmsghdr *nlh, int remaining)
+{
+ return (remaining >= sizeof(struct nlmsghdr) &&
+ nlh->nlmsg_len >= sizeof(struct nlmsghdr) &&
+ nlh->nlmsg_len <= remaining);
+}
+
+/**
+ * nlmsg_next - next netlink message in message stream
+ * @nlh: netlink message header
+ * @remaining: number of bytes remaining in message stream
+ *
+ * Returns the next netlink message in the message stream and
+ * decrements remaining by the size of the current message.
+ */
+static inline struct nlmsghdr *nlmsg_next(struct nlmsghdr *nlh, int *remaining)
+{
+ int totlen = NLMSG_ALIGN(nlh->nlmsg_len);
+
+ *remaining -= totlen;
+
+ return (struct nlmsghdr *) ((unsigned char *) nlh + totlen);
+}
+
+/**
+ * nlmsg_parse - parse attributes of a netlink message
+ * @nlh: netlink message header
+ * @hdrlen: length of family specific header
+ * @tb: destination array with maxtype+1 elements
+ * @maxtype: maximum attribute type to be expected
+ * @policy: validation policy
+ *
+ * See nla_parse()
+ */
+static inline int nlmsg_parse(struct nlmsghdr *nlh, int hdrlen,
+ struct nlattr *tb[], int maxtype,
+ struct nla_policy *policy)
+{
+ if (nlh->nlmsg_len < nlmsg_msg_size(hdrlen))
+ return -EINVAL;
+
+ return nla_parse(tb, maxtype, nlmsg_attrdata(nlh, hdrlen),
+ nlmsg_attrlen(nlh, hdrlen), policy);
+}
+
+/**
+ * nlmsg_find_attr - find a specific attribute in a netlink message
+ * @nlh: netlink message header
+ * @hdrlen: length of familiy specific header
+ * @attrtype: type of attribute to look for
+ *
+ * Returns the first attribute which matches the specified type.
+ */
+static inline struct nlattr *nlmsg_find_attr(struct nlmsghdr *nlh,
+ int hdrlen, int attrtype)
+{
+ return nla_find(nlmsg_attrdata(nlh, hdrlen),
+ nlmsg_attrlen(nlh, hdrlen), attrtype);
+}
+
+/**
+ * nlmsg_validate - validate a netlink message including attributes
+ * @nlh: netlinket message header
+ * @hdrlen: length of familiy specific header
+ * @maxtype: maximum attribute type to be expected
+ * @policy: validation policy
+ */
+static inline int nlmsg_validate(struct nlmsghdr *nlh, int hdrlen, int maxtype,
+ struct nla_policy *policy)
+{
+ if (nlh->nlmsg_len < nlmsg_msg_size(hdrlen))
+ return -EINVAL;
+
+ return nla_validate(nlmsg_attrdata(nlh, hdrlen),
+ nlmsg_attrlen(nlh, hdrlen), maxtype, policy);
+}
+
+/**
+ * nlmsg_for_each_attr - iterate over a stream of attributes
+ * @pos: loop counter, set to current attribute
+ * @nlh: netlink message header
+ * @hdrlen: length of familiy specific header
+ * @rem: initialized to len, holds bytes currently remaining in stream
+ */
+#define nlmsg_for_each_attr(pos, nlh, hdrlen, rem) \
+ nla_for_each_attr(pos, nlmsg_attrdata(nlh, hdrlen), \
+ nlmsg_attrlen(nlh, hdrlen), rem)
+
+#if 0
+/* FIXME: Enable once all users have been converted */
+
+/**
+ * __nlmsg_put - Add a new netlink message to an skb
+ * @skb: socket buffer to store message in
+ * @pid: netlink process id
+ * @seq: sequence number of message
+ * @type: message type
+ * @payload: length of message payload
+ * @flags: message flags
+ *
+ * The caller is responsible to ensure that the skb provides enough
+ * tailroom for both the netlink header and payload.
+ */
+static inline struct nlmsghdr *__nlmsg_put(struct sk_buff *skb, u32 pid,
+ u32 seq, int type, int payload,
+ int flags)
+{
+ struct nlmsghdr *nlh;
+
+ nlh = (struct nlmsghdr *) skb_put(skb, nlmsg_total_size(payload));
+ nlh->nlmsg_type = type;
+ nlh->nlmsg_len = nlmsg_msg_size(payload);
+ nlh->nlmsg_flags = flags;
+ nlh->nlmsg_pid = pid;
+ nlh->nlmsg_seq = seq;
+
+ memset((unsigned char *) nlmsg_data(nlh) + payload, 0,
+ nlmsg_padlen(payload));
+
+ return nlh;
+}
+#endif
+
+/**
+ * nlmsg_put - Add a new netlink message to an skb
+ * @skb: socket buffer to store message in
+ * @pid: netlink process id
+ * @seq: sequence number of message
+ * @type: message type
+ * @payload: length of message payload
+ * @flags: message flags
+ *
+ * Returns NULL if the tailroom of the skb is insufficient to store
+ * the message header and payload.
+ */
+static inline struct nlmsghdr *nlmsg_put(struct sk_buff *skb, u32 pid, u32 seq,
+ int type, int payload, int flags)
+{
+ if (unlikely(skb_tailroom(skb) < nlmsg_total_size(payload)))
+ return NULL;
+
+ return __nlmsg_put(skb, pid, seq, type, payload, flags);
+}
+
+/**
+ * nlmsg_put_answer - Add a new callback based netlink message to an skb
+ * @skb: socket buffer to store message in
+ * @cb: netlink callback
+ * @type: message type
+ * @payload: length of message payload
+ * @flags: message flags
+ *
+ * Returns NULL if the tailroom of the skb is insufficient to store
+ * the message header and payload.
+ */
+static inline struct nlmsghdr *nlmsg_put_answer(struct sk_buff *skb,
+ struct netlink_callback *cb,
+ int type, int payload,
+ int flags)
+{
+ return nlmsg_put(skb, NETLINK_CB(cb->skb).pid, cb->nlh->nlmsg_seq,
+ type, payload, flags);
+}
+
+/**
+ * nlmsg_new - Allocate a new netlink message
+ * @size: maximum size of message
+ *
+ * Use NLMSG_GOODSIZE if size isn't know and you need a good default size.
+ */
+static inline struct sk_buff *nlmsg_new(int size)
+{
+ return alloc_skb(NLMSG_GOODSIZE, GFP_KERNEL);
+}
+
+/**
+ * nlmsg_end - Finalize a netlink message
+ * @skb: socket buffer the message is stored in
+ * @nlh: netlink message header
+ *
+ * Corrects the netlink message header to include the appeneded
+ * attributes. Only necessary if attributes have been added to
+ * the message.
+ *
+ * Returns the total data length of the skb.
+ */
+static inline int nlmsg_end(struct sk_buff *skb, struct nlmsghdr *nlh)
+{
+ nlh->nlmsg_len = skb->tail - (unsigned char *) nlh;
+
+ return skb->len;
+}
+
+/**
+ * nlmsg_cancel - Cancel construction of a netlink message
+ * @skb: socket buffer the message is stored in
+ * @nlh: netlink message header
+ *
+ * Removes the complete netlink message including all
+ * attributes from the socket buffer again. Returns -1.
+ */
+static inline int nlmsg_cancel(struct sk_buff *skb, struct nlmsghdr *nlh)
+{
+ skb_trim(skb, (unsigned char *) nlh - skb->data);
+
+ return -1;
+}
+
+/**
+ * nlmsg_free - free a netlink message
+ * @skb: socket buffer of netlink message
+ */
+static inline void nlmsg_free(struct sk_buff *skb)
+{
+ kfree_skb(skb);
+}
+
+/**
+ * nlmsg_multicast - multicast a netlink message
+ * @sk: netlink socket to spread messages to
+ * @skb: netlink message as socket buffer
+ * @pid: own netlink pid to avoid sending to yourself
+ * @group: multicast group id
+ */
+static inline int nlmsg_multicast(struct sock *sk, struct sk_buff *skb,
+ u32 pid, unsigned int group)
+{
+ int err;
+
+ NETLINK_CB(skb).dst_group = group;
+
+ err = netlink_broadcast(sk, skb, pid, group, GFP_KERNEL);
+ if (err > 0)
+ err = 0;
+
+ return err;
+}
+
+/**
+ * nlmsg_unicast - unicast a netlink message
+ * @sk: netlink socket to spread message to
+ * @skb: netlink message as socket buffer
+ * @pid: netlink pid of the destination socket
+ */
+static inline int nlmsg_unicast(struct sock *sk, struct sk_buff *skb, u32 pid)
+{
+ int err;
+
+ err = netlink_unicast(sk, skb, pid, MSG_DONTWAIT);
+ if (err > 0)
+ err = 0;
+
+ return err;
+}
+
+/**
+ * nlmsg_for_each_msg - iterate over a stream of messages
+ * @pos: loop counter, set to current message
+ * @head: head of message stream
+ * @len: length of message stream
+ * @rem: initialized to len, holds bytes currently remaining in stream
+ */
+#define nlmsg_for_each_msg(pos, head, len, rem) \
+ for (pos = head, rem = len; \
+ nlmsg_ok(pos, rem); \
+ pos = nlmsg_next(pos, &(rem)))
+
+/**************************************************************************
+ * Netlink Attributes
+ **************************************************************************/
+
+/**
+ * nla_attr_size - length of attribute not including padding
+ * @payload: length of payload
+ */
+static inline int nla_attr_size(int payload)
+{
+ return NLA_HDRLEN + payload;
+}
+
+/**
+ * nla_total_size - total length of attribute including padding
+ * @payload: length of payload
+ */
+static inline int nla_total_size(int payload)
+{
+ return NLA_ALIGN(nla_attr_size(payload));
+}
+
+/**
+ * nla_padlen - length of padding at the tail of attribute
+ * @payload: length of payload
+ */
+static inline int nla_padlen(int payload)
+{
+ return nla_total_size(payload) - nla_attr_size(payload);
+}
+
+/**
+ * nla_data - head of payload
+ * @nla: netlink attribute
+ */
+static inline void *nla_data(const struct nlattr *nla)
+{
+ return (char *) nla + NLA_HDRLEN;
+}
+
+/**
+ * nla_len - length of payload
+ * @nla: netlink attribute
+ */
+static inline int nla_len(const struct nlattr *nla)
+{
+ return nla->nla_len - NLA_HDRLEN;
+}
+
+/**
+ * nla_ok - check if the netlink attribute fits into the remaining bytes
+ * @nla: netlink attribute
+ * @remaining: number of bytes remaining in attribute stream
+ */
+static inline int nla_ok(const struct nlattr *nla, int remaining)
+{
+ return remaining >= sizeof(*nla) &&
+ nla->nla_len >= sizeof(*nla) &&
+ nla->nla_len <= remaining;
+}
+
+/**
+ * nla_next - next netlink attribte in attribute stream
+ * @nla: netlink attribute
+ * @remaining: number of bytes remaining in attribute stream
+ *
+ * Returns the next netlink attribute in the attribute stream and
+ * decrements remaining by the size of the current attribute.
+ */
+static inline struct nlattr *nla_next(const struct nlattr *nla, int *remaining)
+{
+ int totlen = NLA_ALIGN(nla->nla_len);
+
+ *remaining -= totlen;
+ return (struct nlattr *) ((char *) nla + totlen);
+}
+
+/**
+ * nla_parse_nested - parse nested attributes
+ * @tb: destination array with maxtype+1 elements
+ * @maxtype: maximum attribute type to be expected
+ * @nla: attribute containing the nested attributes
+ * @policy: validation policy
+ *
+ * See nla_parse()
+ */
+static inline int nla_parse_nested(struct nlattr *tb[], int maxtype,
+ struct nlattr *nla,
+ struct nla_policy *policy)
+{
+ return nla_parse(tb, maxtype, nla_data(nla), nla_len(nla), policy);
+}
+/**
+ * nla_put_u8 - Add a u16 netlink attribute to a socket buffer
+ * @skb: socket buffer to add attribute to
+ * @attrtype: attribute type
+ * @value: numeric value
+ */
+static inline int nla_put_u8(struct sk_buff *skb, int attrtype, u8 value)
+{
+ return nla_put(skb, attrtype, sizeof(u8), &value);
+}
+
+/**
+ * nla_put_u16 - Add a u16 netlink attribute to a socket buffer
+ * @skb: socket buffer to add attribute to
+ * @attrtype: attribute type
+ * @value: numeric value
+ */
+static inline int nla_put_u16(struct sk_buff *skb, int attrtype, u16 value)
+{
+ return nla_put(skb, attrtype, sizeof(u16), &value);
+}
+
+/**
+ * nla_put_u32 - Add a u32 netlink attribute to a socket buffer
+ * @skb: socket buffer to add attribute to
+ * @attrtype: attribute type
+ * @value: numeric value
+ */
+static inline int nla_put_u32(struct sk_buff *skb, int attrtype, u32 value)
+{
+ return nla_put(skb, attrtype, sizeof(u32), &value);
+}
+
+/**
+ * nla_put_64 - Add a u64 netlink attribute to a socket buffer
+ * @skb: socket buffer to add attribute to
+ * @attrtype: attribute type
+ * @value: numeric value
+ */
+static inline int nla_put_u64(struct sk_buff *skb, int attrtype, u64 value)
+{
+ return nla_put(skb, attrtype, sizeof(u64), &value);
+}
+
+/**
+ * nla_put_string - Add a string netlink attribute to a socket buffer
+ * @skb: socket buffer to add attribute to
+ * @attrtype: attribute type
+ * @str: NUL terminated string
+ */
+static inline int nla_put_string(struct sk_buff *skb, int attrtype,
+ const char *str)
+{
+ return nla_put(skb, attrtype, strlen(str) + 1, str);
+}
+
+/**
+ * nla_put_flag - Add a flag netlink attribute to a socket buffer
+ * @skb: socket buffer to add attribute to
+ * @attrtype: attribute type
+ */
+static inline int nla_put_flag(struct sk_buff *skb, int attrtype)
+{
+ return nla_put(skb, attrtype, 0, NULL);
+}
+
+/**
+ * nla_put_msecs - Add a msecs netlink attribute to a socket buffer
+ * @skb: socket buffer to add attribute to
+ * @attrtype: attribute type
+ * @jiffies: number of msecs in jiffies
+ */
+static inline int nla_put_msecs(struct sk_buff *skb, int attrtype,
+ unsigned long jiffies)
+{
+ u64 tmp = jiffies_to_msecs(jiffies);
+ return nla_put(skb, attrtype, sizeof(u64), &tmp);
+}
+
+#define NLA_PUT(skb, attrtype, attrlen, data) \
+ do { \
+ if (nla_put(skb, attrtype, attrlen, data) < 0) \
+ goto nla_put_failure; \
+ } while(0)
+
+#define NLA_PUT_TYPE(skb, type, attrtype, value) \
+ do { \
+ type __tmp = value; \
+ NLA_PUT(skb, attrtype, sizeof(type), &__tmp); \
+ } while(0)
+
+#define NLA_PUT_U8(skb, attrtype, value) \
+ NLA_PUT_TYPE(skb, u8, attrtype, value)
+
+#define NLA_PUT_U16(skb, attrtype, value) \
+ NLA_PUT_TYPE(skb, u16, attrtype, value)
+
+#define NLA_PUT_U32(skb, attrtype, value) \
+ NLA_PUT_TYPE(skb, u32, attrtype, value)
+
+#define NLA_PUT_U64(skb, attrtype, value) \
+ NLA_PUT_TYPE(skb, u64, attrtype, value)
+
+#define NLA_PUT_STRING(skb, attrtype, value) \
+ NLA_PUT(skb, attrtype, strlen(value) + 1, value)
+
+#define NLA_PUT_FLAG(skb, attrtype, value) \
+ NLA_PUT(skb, attrtype, 0, NULL)
+
+#define NLA_PUT_MSECS(skb, attrtype, jiffies) \
+ NLA_PUT_U64(skb, attrtype, jiffies_to_msecs(jiffies))
+
+/**
+ * nla_get_u32 - return payload of u32 attribute
+ * @nla: u32 netlink attribute
+ */
+static inline u32 nla_get_u32(struct nlattr *nla)
+{
+ return *(u32 *) nla_data(nla);
+}
+
+/**
+ * nla_get_u16 - return payload of u16 attribute
+ * @nla: u16 netlink attribute
+ */
+static inline u16 nla_get_u16(struct nlattr *nla)
+{
+ return *(u16 *) nla_data(nla);
+}
+
+/**
+ * nla_get_u8 - return payload of u8 attribute
+ * @nla: u8 netlink attribute
+ */
+static inline u8 nla_get_u8(struct nlattr *nla)
+{
+ return *(u8 *) nla_data(nla);
+}
+
+/**
+ * nla_get_u64 - return payload of u64 attribute
+ * @nla: u64 netlink attribute
+ */
+static inline u64 nla_get_u64(struct nlattr *nla)
+{
+ u64 tmp;
+
+ nla_memcpy(&tmp, nla, sizeof(tmp));
+
+ return tmp;
+}
+
+/**
+ * nla_get_flag - return payload of flag attribute
+ * @nla: flag netlink attribute
+ */
+static inline int nla_get_flag(struct nlattr *nla)
+{
+ return !!nla;
+}
+
+/**
+ * nla_get_msecs - return payload of msecs attribute
+ * @nla: msecs netlink attribute
+ *
+ * Returns the number of milliseconds in jiffies.
+ */
+static inline unsigned long nla_get_msecs(struct nlattr *nla)
+{
+ u64 msecs = nla_get_u64(nla);
+
+ return msecs_to_jiffies((unsigned long) msecs);
+}
+
+/**
+ * nla_nest_start - Start a new level of nested attributes
+ * @skb: socket buffer to add attributes to
+ * @attrtype: attribute type of container
+ *
+ * Returns the container attribute
+ */
+static inline struct nlattr *nla_nest_start(struct sk_buff *skb, int attrtype)
+{
+ struct nlattr *start = (struct nlattr *) skb->tail;
+
+ if (nla_put(skb, attrtype, 0, NULL) < 0)
+ return NULL;
+
+ return start;
+}
+
+/**
+ * nla_nest_end - Finalize nesting of attributes
+ * @skb: socket buffer the attribtues are stored in
+ * @start: container attribute
+ *
+ * Corrects the container attribute header to include the all
+ * appeneded attributes.
+ *
+ * Returns the total data length of the skb.
+ */
+static inline int nla_nest_end(struct sk_buff *skb, struct nlattr *start)
+{
+ start->nla_len = skb->tail - (unsigned char *) start;
+ return skb->len;
+}
+
+/**
+ * nla_nest_cancel - Cancel nesting of attributes
+ * @skb: socket buffer the message is stored in
+ * @start: container attribute
+ *
+ * Removes the container attribute and including all nested
+ * attributes. Returns -1.
+ */
+static inline int nla_nest_cancel(struct sk_buff *skb, struct nlattr *start)
+{
+ if (start)
+ skb_trim(skb, (unsigned char *) start - skb->data);
+
+ return -1;
+}
+
+/**
+ * nla_for_each_attr - iterate over a stream of attributes
+ * @pos: loop counter, set to current attribute
+ * @head: head of attribute stream
+ * @len: length of attribute stream
+ * @rem: initialized to len, holds bytes currently remaining in stream
+ */
+#define nla_for_each_attr(pos, head, len, rem) \
+ for (pos = head, rem = len; \
+ nla_ok(pos, rem); \
+ pos = nla_next(pos, &(rem)))
+
+#endif
diff --git a/net/netlink/Makefile b/net/netlink/Makefile
index 39d9c2d..6817901 100644
--- a/net/netlink/Makefile
+++ b/net/netlink/Makefile
@@ -2,4 +2,4 @@
# Makefile for the netlink driver.
#
-obj-y := af_netlink.o
+obj-y := af_netlink.o attr.o
diff --git a/net/netlink/attr.c b/net/netlink/attr.c
new file mode 100644
index 0000000..fffef4a
--- /dev/null
+++ b/net/netlink/attr.c
@@ -0,0 +1,328 @@
+/*
+ * NETLINK Netlink attributes
+ *
+ * Authors: Thomas Graf <tgraf@suug.ch>
+ * Alexey Kuznetsov <kuznet@ms2.inr.ac.ru>
+ */
+
+#include <linux/config.h>
+#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_STRING] = 1,
+ [NLA_NESTED] = NLA_HDRLEN,
+};
+
+static int validate_nla(struct nlattr *nla, int maxtype,
+ struct nla_policy *policy)
+{
+ struct nla_policy *pt;
+ int minlen = 0;
+
+ if (nla->nla_type <= 0 || nla->nla_type > maxtype)
+ return 0;
+
+ pt = &policy[nla->nla_type];
+
+ BUG_ON(pt->type > NLA_TYPE_MAX);
+
+ if (pt->minlen)
+ minlen = pt->minlen;
+ else if (pt->type != NLA_UNSPEC)
+ minlen = nla_attr_minlen[pt->type];
+
+ if (pt->type == NLA_FLAG && nla_len(nla) > 0)
+ return -ERANGE;
+
+ if (nla_len(nla) < 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,
+ 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,
+ 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 - 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_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 - 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;
+}
+
+
+EXPORT_SYMBOL(nla_validate);
+EXPORT_SYMBOL(nla_parse);
+EXPORT_SYMBOL(nla_find);
+EXPORT_SYMBOL(nla_strlcpy);
+EXPORT_SYMBOL(__nla_reserve);
+EXPORT_SYMBOL(nla_reserve);
+EXPORT_SYMBOL(__nla_put);
+EXPORT_SYMBOL(nla_put);
+EXPORT_SYMBOL(nla_memcpy);
+EXPORT_SYMBOL(nla_memcmp);
+EXPORT_SYMBOL(nla_strcmp);
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