Netlink message helpers

Collaboration diagram for Netlink message helpers:

Modules
	Netlink message batch helpers

Functions
size_t	mnl_nlmsg_size (size_t len)
size_t	mnl_nlmsg_get_payload_len (const struct nlmsghdr *nlh)
struct nlmsghdr *	mnl_nlmsg_put_header (void *buf)
void *	mnl_nlmsg_put_extra_header (struct nlmsghdr *nlh, size_t size)
void *	mnl_nlmsg_get_payload (const struct nlmsghdr *nlh)
void *	mnl_nlmsg_get_payload_offset (const struct nlmsghdr *nlh, size_t offset)
bool	mnl_nlmsg_ok (const struct nlmsghdr *nlh, int len)
struct nlmsghdr *	mnl_nlmsg_next (const struct nlmsghdr *nlh, int *len)
void *	mnl_nlmsg_get_payload_tail (const struct nlmsghdr *nlh)
bool	mnl_nlmsg_seq_ok (const struct nlmsghdr *nlh, unsigned int seq)
bool	mnl_nlmsg_portid_ok (const struct nlmsghdr *nlh, unsigned int portid)
void	mnl_nlmsg_fprintf (FILE *fd, const void *data, size_t datalen, size_t extra_header_size)

Variables
void *	mnl_nlmsg_batch::buf
size_t	mnl_nlmsg_batch::limit
size_t	mnl_nlmsg_batch::buflen
void *	mnl_nlmsg_batch::cur
bool	mnl_nlmsg_batch::overflow

Detailed Description

Netlink message:

        |<----------------- 4 bytes ------------------->|
        |<----- 2 bytes ------>|<------- 2 bytes ------>|
        |-----------------------------------------------|
        |      Message length (including header)        |
        |-----------------------------------------------|
        |     Message type     |     Message flags      |
        |-----------------------------------------------|
        |           Message sequence number             |
        |-----------------------------------------------|
        |                 Netlink PortID                |
        |-----------------------------------------------|
        |                                               |
        .                   Payload                     .
        |_______________________________________________|

There is usually an extra header after the the Netlink header (at the beginning of the payload). This extra header is specific of the Netlink subsystem. After this extra header, it comes the sequence of attributes that are expressed in Type-Length-Value (TLV) format.