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libmnl 1.0.5
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Functions | |
| int | mnl_socket_get_fd (const struct mnl_socket *nl) |
| unsigned int | mnl_socket_get_portid (const struct mnl_socket *nl) |
| struct mnl_socket * | mnl_socket_open (int bus) |
| struct mnl_socket * | mnl_socket_open2 (int bus, int flags) |
| struct mnl_socket * | mnl_socket_fdopen (int fd) |
| int | mnl_socket_bind (struct mnl_socket *nl, unsigned int groups, pid_t pid) |
| ssize_t | mnl_socket_sendto (const struct mnl_socket *nl, const void *buf, size_t len) |
| ssize_t | mnl_socket_recvfrom (const struct mnl_socket *nl, void *buf, size_t bufsiz) |
| int | mnl_socket_close (struct mnl_socket *nl) |
| int | mnl_socket_setsockopt (const struct mnl_socket *nl, int type, void *buf, socklen_t len) |
| int | mnl_socket_getsockopt (const struct mnl_socket *nl, int type, void *buf, socklen_t *len) |
| int mnl_socket_bind | ( | struct mnl_socket * | nl, |
| unsigned int | groups, | ||
| pid_t | pid | ||
| ) |
mnl_socket_bind - bind netlink socket
| nl | netlink socket obtained via mnl_socket_open() |
| groups | the group of message you're interested in |
| pid | the port ID you want to use (use zero for automatic selection) |
On error, this function returns -1 and errno is appropriately set. On success, 0 is returned. You can use MNL_SOCKET_AUTOPID which is 0 for automatic port ID selection.
| int mnl_socket_close | ( | struct mnl_socket * | nl | ) |
mnl_socket_close - close a given netlink socket
| nl | netlink socket obtained via mnl_socket_open() |
On error, this function returns -1 and errno is appropriately set. On success, it returns 0.
| struct mnl_socket * mnl_socket_fdopen | ( | int | fd | ) |
mnl_socket_fdopen - associates a mnl_socket object with pre-existing socket.
| fd | pre-existing socket descriptor. |
On error, it returns NULL and errno is appropriately set. Otherwise, it returns a valid pointer to the mnl_socket structure. It also sets the portID if the socket fd is already bound and it is AF_NETLINK.
Note that mnl_socket_get_portid() returns 0 if this function is used with non-netlink socket.
| int mnl_socket_get_fd | ( | const struct mnl_socket * | nl | ) |
mnl_socket_get_fd - obtain file descriptor from netlink socket
| nl | netlink socket obtained via mnl_socket_open() |
This function returns the file descriptor of a given netlink socket.
| unsigned int mnl_socket_get_portid | ( | const struct mnl_socket * | nl | ) |
mnl_socket_get_portid - obtain Netlink PortID from netlink socket
| nl | netlink socket obtained via mnl_socket_open() |
This function returns the Netlink PortID of a given netlink socket. It's a common mistake to assume that this PortID equals the process ID which is not always true. This is the case if you open more than one socket that is binded to the same Netlink subsystem from the same process.
| int mnl_socket_getsockopt | ( | const struct mnl_socket * | nl, |
| int | type, | ||
| void * | buf, | ||
| socklen_t * | len | ||
| ) |
mnl_socket_getsockopt - get a Netlink socket option
| nl | netlink socket obtained via mnl_socket_open() |
| type | type of Netlink socket options |
| buf | pointer to the buffer to store the value of this option |
| len | size of the information written in the buffer |
On error, this function returns -1 and errno is appropriately set.
| struct mnl_socket * mnl_socket_open | ( | int | bus | ) |
| struct mnl_socket * mnl_socket_open2 | ( | int | bus, |
| int | flags | ||
| ) |
mnl_socket_open2 - open a netlink socket with appropriate flags
| bus | the netlink socket bus ID (see NETLINK_* constants) |
| flags | the netlink socket flags (see SOCK_* constants in socket(2)) |
This is similar to mnl_socket_open(), but allows to set flags like SOCK_CLOEXEC at socket creation time (useful for multi-threaded programs performing exec calls).
On error, it returns NULL and errno is appropriately set. Otherwise, it returns a valid pointer to the mnl_socket structure.
| ssize_t mnl_socket_recvfrom | ( | const struct mnl_socket * | nl, |
| void * | buf, | ||
| size_t | bufsiz | ||
| ) |
mnl_socket_recvfrom - receive a netlink message
| nl | netlink socket obtained via mnl_socket_open() |
| buf | buffer that you want to use to store the netlink message |
| bufsiz | size of the buffer passed to store the netlink message |
On error, it returns -1 and errno is appropriately set. If errno is set to ENOSPC, it means that the buffer that you have passed to store the netlink message is too small, so you have received a truncated message. To avoid this, you have to allocate a buffer of MNL_SOCKET_BUFFER_SIZE (which is 8KB, see linux/netlink.h for more information). Using this buffer size ensures that your buffer is big enough to store the netlink message without truncating it.
| ssize_t mnl_socket_sendto | ( | const struct mnl_socket * | nl, |
| const void * | buf, | ||
| size_t | len | ||
| ) |
mnl_socket_sendto - send a netlink message of a certain size
| nl | netlink socket obtained via mnl_socket_open() |
| buf | buffer containing the netlink message to be sent |
| len | number of bytes in the buffer that you want to send |
On error, it returns -1 and errno is appropriately set. Otherwise, it returns the number of bytes sent.
| int mnl_socket_setsockopt | ( | const struct mnl_socket * | nl, |
| int | type, | ||
| void * | buf, | ||
| socklen_t | len | ||
| ) |
mnl_socket_setsockopt - set Netlink socket option
| nl | netlink socket obtained via mnl_socket_open() |
| type | type of Netlink socket options |
| buf | the buffer that contains the data about this option |
| len | the size of the buffer passed |
This function allows you to set some Netlink socket option. As of writing this (see linux/netlink.h), the existing options are:
- \#define NETLINK_ADD_MEMBERSHIP 1 - \#define NETLINK_DROP_MEMBERSHIP 2 - \#define NETLINK_PKTINFO 3 - \#define NETLINK_BROADCAST_ERROR 4 - \#define NETLINK_NO_ENOBUFS 5
In the early days, Netlink only supported 32 groups expressed in a 32-bits mask. However, since 2.6.14, Netlink may have up to 2^32 multicast groups but you have to use setsockopt() with NETLINK_ADD_MEMBERSHIP to join a given multicast group. This function internally calls setsockopt() to join a given netlink multicast group. You can still use mnl_bind() and the 32-bit mask to join a set of Netlink multicast groups.
On error, this function returns -1 and errno is appropriately set.
1.9.4