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      1 /*
      2  * Copyright (C) 2011 The Android Open Source Project
      3  *
      4  * Licensed under the Apache License, Version 2.0 (the "License");
      5  * you may not use this file except in compliance with the License.
      6  * You may obtain a copy of the License at
      7  *
      8  *	http://www.apache.org/licenses/LICENSE-2.0
      9  *
     10  * Unless required by applicable law or agreed to in writing, software
     11  * distributed under the License is distributed on an "AS IS" BASIS,
     12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     13  * See the License for the specific language governing permissions and
     14  * limitations under the License.
     15  */
     16 
     17 /* NOTICE: This is a clean room re-implementation of libnl */
     18 
     19 #include <errno.h>
     20 #include <unistd.h>
     21 #include <malloc.h>
     22 #include <sys/time.h>
     23 #include <sys/socket.h>
     24 #include "netlink-types.h"
     25 
     26 /* Join group */
     27 int nl_socket_add_membership(struct nl_sock *sk, int group)
     28 {
     29 	return setsockopt(sk->s_fd, SOL_NETLINK,
     30 			NETLINK_ADD_MEMBERSHIP, &group, sizeof(group));
     31 }
     32 
     33 /* Allocate new netlink socket. */
     34 static struct nl_sock *_nl_socket_alloc(void)
     35 {
     36 	struct nl_sock *sk;
     37 	struct timeval tv;
     38 	struct nl_cb *cb;
     39 
     40 	sk = (struct nl_sock *) malloc(sizeof(struct nl_sock));
     41 	if (!sk)
     42 		return NULL;
     43 	memset(sk, 0, sizeof(*sk));
     44 
     45 	/* Get current time */
     46 
     47 	if (gettimeofday(&tv, NULL))
     48 		goto fail;
     49 	else
     50 		sk->s_seq_next = (int) tv.tv_sec;
     51 
     52 	/* Create local socket */
     53 	sk->s_local.nl_family = AF_NETLINK;
     54 	sk->s_local.nl_pid = 0; /* Kernel fills in pid */
     55 	sk->s_local.nl_groups = 0; /* No groups */
     56 
     57 	/* Create peer socket */
     58 	sk->s_peer.nl_family = AF_NETLINK;
     59 	sk->s_peer.nl_pid = 0; /* Kernel */
     60 	sk->s_peer.nl_groups = 0; /* No groups */
     61 
     62 	return sk;
     63 fail:
     64 	free(sk);
     65 	return NULL;
     66 }
     67 
     68 /* Allocate new netlink socket. */
     69 struct nl_sock *nl_socket_alloc(void)
     70 {
     71 	struct nl_sock *sk = _nl_socket_alloc();
     72 	struct nl_cb *cb;
     73 
     74 	if (!sk)
     75 		return NULL;
     76 
     77 	cb = nl_cb_alloc(NL_CB_DEFAULT);
     78 	if (!cb)
     79 		goto cb_fail;
     80 	sk->s_cb = cb;
     81 	return sk;
     82 cb_fail:
     83 	free(sk);
     84 	return NULL;
     85 }
     86 
     87 /* Allocate new socket with custom callbacks. */
     88 struct nl_sock *nl_socket_alloc_cb(struct nl_cb *cb)
     89 {
     90 	struct nl_sock *sk = _nl_socket_alloc();
     91 
     92 	if (!sk)
     93 		return NULL;
     94 
     95 	sk->s_cb = cb;
     96 	nl_cb_get(cb);
     97 
     98 	return sk;
     99 }
    100 
    101 /* Free a netlink socket. */
    102 void nl_socket_free(struct nl_sock *sk)
    103 {
    104 	nl_cb_put(sk->s_cb);
    105 	close(sk->s_fd);
    106 	free(sk);
    107 }
    108 
    109 /* Sets socket buffer size of netlink socket */
    110 int nl_socket_set_buffer_size(struct nl_sock *sk, int rxbuf, int txbuf)
    111 {
    112 	if (setsockopt(sk->s_fd, SOL_SOCKET, SO_SNDBUF, \
    113 			&rxbuf, (socklen_t) sizeof(rxbuf)))
    114 		goto error;
    115 
    116 	if (setsockopt(sk->s_fd, SOL_SOCKET, SO_RCVBUF, \
    117 			&txbuf, (socklen_t) sizeof(txbuf)))
    118 		goto error;
    119 
    120 	return 0;
    121 error:
    122 	return -errno;
    123 
    124 }
    125 
    126 int nl_socket_get_fd(struct nl_sock *sk)
    127 {
    128 	return sk->s_fd;
    129 }
    130