/branches/gl-inet/package/libs/libnl-tiny/src/socket.c |
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/* |
* lib/socket.c Netlink Socket |
* |
* This library is free software; you can redistribute it and/or |
* modify it under the terms of the GNU Lesser General Public |
* License as published by the Free Software Foundation version 2.1 |
* of the License. |
* |
* Copyright (c) 2003-2008 Thomas Graf <tgraf@suug.ch> |
*/ |
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/** |
* @ingroup core |
* @defgroup socket Socket |
* @{ |
*/ |
|
#include <netlink-local.h> |
#include <netlink/netlink.h> |
#include <netlink/utils.h> |
#include <netlink/handlers.h> |
#include <netlink/msg.h> |
#include <netlink/attr.h> |
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static uint32_t used_ports_map[32]; |
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static uint32_t generate_local_port(void) |
{ |
int i, n; |
uint32_t pid = getpid() & 0x3FFFFF; |
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for (i = 0; i < 32; i++) { |
if (used_ports_map[i] == 0xFFFFFFFF) |
continue; |
|
for (n = 0; n < 32; n++) { |
if (1UL & (used_ports_map[i] >> n)) |
continue; |
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used_ports_map[i] |= (1UL << n); |
n += (i * 32); |
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/* PID_MAX_LIMIT is currently at 2^22, leaving 10 bit |
* to, i.e. 1024 unique ports per application. */ |
return pid + (n << 22); |
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} |
} |
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/* Out of sockets in our own PID namespace, what to do? FIXME */ |
return UINT_MAX; |
} |
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static void release_local_port(uint32_t port) |
{ |
int nr; |
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if (port == UINT_MAX) |
return; |
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nr = port >> 22; |
used_ports_map[nr / 32] &= ~(1 << nr % 32); |
} |
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/** |
* @name Allocation |
* @{ |
*/ |
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static struct nl_sock *__alloc_socket(struct nl_cb *cb) |
{ |
struct nl_sock *sk; |
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sk = calloc(1, sizeof(*sk)); |
if (!sk) |
return NULL; |
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sk->s_fd = -1; |
sk->s_cb = cb; |
sk->s_local.nl_family = AF_NETLINK; |
sk->s_peer.nl_family = AF_NETLINK; |
sk->s_seq_expect = sk->s_seq_next = time(0); |
sk->s_local.nl_pid = generate_local_port(); |
if (sk->s_local.nl_pid == UINT_MAX) { |
nl_socket_free(sk); |
return NULL; |
} |
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return sk; |
} |
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/** |
* Allocate new netlink socket |
* |
* @return Newly allocated netlink socket or NULL. |
*/ |
struct nl_sock *nl_socket_alloc(void) |
{ |
struct nl_cb *cb; |
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cb = nl_cb_alloc(NL_CB_DEFAULT); |
if (!cb) |
return NULL; |
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return __alloc_socket(cb); |
} |
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/** |
* Allocate new socket with custom callbacks |
* @arg cb Callback handler |
* |
* The reference to the callback handler is taken into account |
* automatically, it is released again upon calling nl_socket_free(). |
* |
*@return Newly allocted socket handle or NULL. |
*/ |
struct nl_sock *nl_socket_alloc_cb(struct nl_cb *cb) |
{ |
if (cb == NULL) |
BUG(); |
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return __alloc_socket(nl_cb_get(cb)); |
} |
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/** |
* Free a netlink socket. |
* @arg sk Netlink socket. |
*/ |
void nl_socket_free(struct nl_sock *sk) |
{ |
if (!sk) |
return; |
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if (sk->s_fd >= 0) |
close(sk->s_fd); |
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if (!(sk->s_flags & NL_OWN_PORT)) |
release_local_port(sk->s_local.nl_pid); |
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nl_cb_put(sk->s_cb); |
free(sk); |
} |
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/** @} */ |
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/** |
* @name Sequence Numbers |
* @{ |
*/ |
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static int noop_seq_check(struct nl_msg *msg, void *arg) |
{ |
return NL_OK; |
} |
|
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/** |
* Disable sequence number checking. |
* @arg sk Netlink socket. |
* |
* Disables checking of sequence numbers on the netlink socket This is |
* required to allow messages to be processed which were not requested by |
* a preceding request message, e.g. netlink events. |
* |
* @note This function modifies the NL_CB_SEQ_CHECK configuration in |
* the callback handle associated with the socket. |
*/ |
void nl_socket_disable_seq_check(struct nl_sock *sk) |
{ |
nl_cb_set(sk->s_cb, NL_CB_SEQ_CHECK, |
NL_CB_CUSTOM, noop_seq_check, NULL); |
} |
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/** @} */ |
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/** |
* Set local port of socket |
* @arg sk Netlink socket. |
* @arg port Local port identifier |
* |
* Assigns a local port identifier to the socket. If port is 0 |
* a unique port identifier will be generated automatically. |
*/ |
void nl_socket_set_local_port(struct nl_sock *sk, uint32_t port) |
{ |
if (port == 0) { |
port = generate_local_port(); |
sk->s_flags &= ~NL_OWN_PORT; |
} else { |
if (!(sk->s_flags & NL_OWN_PORT)) |
release_local_port(sk->s_local.nl_pid); |
sk->s_flags |= NL_OWN_PORT; |
} |
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sk->s_local.nl_pid = port; |
} |
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/** @} */ |
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/** |
* @name Group Subscriptions |
* @{ |
*/ |
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/** |
* Join groups |
* @arg sk Netlink socket |
* @arg group Group identifier |
* |
* Joins the specified groups using the modern socket option which |
* is available since kernel version 2.6.14. It allows joining an |
* almost arbitary number of groups without limitation. The list |
* of groups has to be terminated by 0 (%NFNLGRP_NONE). |
* |
* Make sure to use the correct group definitions as the older |
* bitmask definitions for nl_join_groups() are likely to still |
* be present for backward compatibility reasons. |
* |
* @return 0 on sucess or a negative error code. |
*/ |
int nl_socket_add_memberships(struct nl_sock *sk, int group, ...) |
{ |
int err; |
va_list ap; |
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if (sk->s_fd == -1) |
return -NLE_BAD_SOCK; |
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va_start(ap, group); |
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while (group != 0) { |
if (group < 0) |
return -NLE_INVAL; |
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err = setsockopt(sk->s_fd, SOL_NETLINK, NETLINK_ADD_MEMBERSHIP, |
&group, sizeof(group)); |
if (err < 0) |
return -nl_syserr2nlerr(errno); |
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group = va_arg(ap, int); |
} |
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va_end(ap); |
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return 0; |
} |
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/** |
* Leave groups |
* @arg sk Netlink socket |
* @arg group Group identifier |
* |
* Leaves the specified groups using the modern socket option |
* which is available since kernel version 2.6.14. The list of groups |
* has to terminated by 0 (%NFNLGRP_NONE). |
* |
* @see nl_socket_add_membership |
* @return 0 on success or a negative error code. |
*/ |
int nl_socket_drop_memberships(struct nl_sock *sk, int group, ...) |
{ |
int err; |
va_list ap; |
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if (sk->s_fd == -1) |
return -NLE_BAD_SOCK; |
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va_start(ap, group); |
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while (group != 0) { |
if (group < 0) |
return -NLE_INVAL; |
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err = setsockopt(sk->s_fd, SOL_NETLINK, NETLINK_DROP_MEMBERSHIP, |
&group, sizeof(group)); |
if (err < 0) |
return -nl_syserr2nlerr(errno); |
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group = va_arg(ap, int); |
} |
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va_end(ap); |
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return 0; |
} |
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/** @} */ |
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/** |
* Set file descriptor of socket to non-blocking state |
* @arg sk Netlink socket. |
* |
* @return 0 on success or a negative error code. |
*/ |
int nl_socket_set_nonblocking(struct nl_sock *sk) |
{ |
if (sk->s_fd == -1) |
return -NLE_BAD_SOCK; |
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if (fcntl(sk->s_fd, F_SETFL, O_NONBLOCK) < 0) |
return -nl_syserr2nlerr(errno); |
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return 0; |
} |
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/** @} */ |
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/** |
* @name Utilities |
* @{ |
*/ |
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/** |
* Set socket buffer size of netlink socket. |
* @arg sk Netlink socket. |
* @arg rxbuf New receive socket buffer size in bytes. |
* @arg txbuf New transmit socket buffer size in bytes. |
* |
* Sets the socket buffer size of a netlink socket to the specified |
* values \c rxbuf and \c txbuf. Providing a value of \c 0 assumes a |
* good default value. |
* |
* @note It is not required to call this function prior to nl_connect(). |
* @return 0 on sucess or a negative error code. |
*/ |
int nl_socket_set_buffer_size(struct nl_sock *sk, int rxbuf, int txbuf) |
{ |
int err; |
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if (rxbuf <= 0) |
rxbuf = 32768; |
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if (txbuf <= 0) |
txbuf = 32768; |
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if (sk->s_fd == -1) |
return -NLE_BAD_SOCK; |
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err = setsockopt(sk->s_fd, SOL_SOCKET, SO_SNDBUF, |
&txbuf, sizeof(txbuf)); |
if (err < 0) |
return -nl_syserr2nlerr(errno); |
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err = setsockopt(sk->s_fd, SOL_SOCKET, SO_RCVBUF, |
&rxbuf, sizeof(rxbuf)); |
if (err < 0) |
return -nl_syserr2nlerr(errno); |
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sk->s_flags |= NL_SOCK_BUFSIZE_SET; |
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return 0; |
} |
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/** |
* Enable/disable credential passing on netlink socket. |
* @arg sk Netlink socket. |
* @arg state New state (0 - disabled, 1 - enabled) |
* |
* @return 0 on success or a negative error code |
*/ |
int nl_socket_set_passcred(struct nl_sock *sk, int state) |
{ |
int err; |
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if (sk->s_fd == -1) |
return -NLE_BAD_SOCK; |
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err = setsockopt(sk->s_fd, SOL_SOCKET, SO_PASSCRED, |
&state, sizeof(state)); |
if (err < 0) |
return -nl_syserr2nlerr(errno); |
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if (state) |
sk->s_flags |= NL_SOCK_PASSCRED; |
else |
sk->s_flags &= ~NL_SOCK_PASSCRED; |
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return 0; |
} |
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/** |
* Enable/disable receival of additional packet information |
* @arg sk Netlink socket. |
* @arg state New state (0 - disabled, 1 - enabled) |
* |
* @return 0 on success or a negative error code |
*/ |
int nl_socket_recv_pktinfo(struct nl_sock *sk, int state) |
{ |
int err; |
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if (sk->s_fd == -1) |
return -NLE_BAD_SOCK; |
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err = setsockopt(sk->s_fd, SOL_NETLINK, NETLINK_PKTINFO, |
&state, sizeof(state)); |
if (err < 0) |
return -nl_syserr2nlerr(errno); |
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return 0; |
} |
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/** @} */ |
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/** @} */ |