diff options
| -rw-r--r-- | include/linux/netlink.h | 24 | ||||
| -rw-r--r-- | include/net/netlink.h | 877 | ||||
| -rw-r--r-- | net/netlink/Makefile | 2 | ||||
| -rw-r--r-- | net/netlink/attr.c | 328 |
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); |