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/*
* Copyright (C) 2011 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
/* NOTICE: This is a clean room re-implementation of libnl */
#include <errno.h>
#include <string.h>
#include <unistd.h>
#include <fcntl.h>
#include <sys/socket.h>
#include "netlink-types.h"
#define NL_BUFFER_SZ (32768U)
/* Checks message for completeness and sends it out */
int nl_send_auto_complete(struct nl_sock *sk, struct nl_msg *msg)
{
struct nlmsghdr *nlh = msg->nm_nlh;
struct timeval tv;
if (!nlh) {
int errsv = errno;
fprintf(stderr, "Netlink message header is NULL!\n");
return -errsv;
}
/* Complete the nl_msg header */
if (gettimeofday(&tv, NULL))
nlh->nlmsg_seq = 1;
else
nlh->nlmsg_seq = (int) tv.tv_sec;
nlh->nlmsg_pid = sk->s_local.nl_pid;
nlh->nlmsg_flags |= NLM_F_REQUEST | NLM_F_ACK;
return nl_send(sk, msg);
}
/* Receives a netlink message, allocates a buffer in *buf and stores
* the message content. The peer's netlink address is stored in
* *nla. The caller is responsible for freeing the buffer allocated in
* *buf if a positive value is returned. Interrupted system calls are
* handled by repeating the read. The input buffer size is determined
* by peeking before the actual read is done */
int nl_recv(struct nl_sock *sk, struct sockaddr_nl *nla, \
unsigned char **buf, struct ucred **creds)
{
int rc = -1;
int sk_flags;
int RECV_BUF_SIZE;
int errsv;
struct iovec recvmsg_iov;
struct msghdr msg;
/* Allocate buffer */
RECV_BUF_SIZE = getpagesize();
*buf = (unsigned char *) malloc(RECV_BUF_SIZE);
if (!buf) {
rc = -ENOMEM;
goto fail;
}
/* Prepare to receive message */
recvmsg_iov.iov_base = *buf;
recvmsg_iov.iov_len = RECV_BUF_SIZE;
msg.msg_name = (void *) &sk->s_peer;
msg.msg_namelen = sizeof(sk->s_peer);
msg.msg_iov = &recvmsg_iov;
msg.msg_iovlen = 1;
msg.msg_control = NULL;
msg.msg_controllen = 0;
msg.msg_flags = 0;
/* Make non blocking and then restore previous setting */
sk_flags = fcntl(sk->s_fd, F_GETFL, 0);
fcntl(sk->s_fd, F_SETFL, O_NONBLOCK);
rc = recvmsg(sk->s_fd, &msg, 0);
errsv = errno;
fcntl(sk->s_fd, F_SETFL, sk_flags);
if (rc < 0)
rc = -errsv;
fail:
return rc;
}
/* Receive a set of messages from a netlink socket */
/* NOTE: Does not currently support callback replacements!!! */
int nl_recvmsgs(struct nl_sock *sk, struct nl_cb *cb)
{
struct sockaddr_nl nla;
struct ucred *creds;
int rc, cb_rc = NL_OK, done = 0;
do {
unsigned char *buf;
int i, rem, flags;
struct nlmsghdr *nlh;
struct nlmsgerr *nlme;
struct nl_msg *msg;
done = 0;
rc = nl_recv(sk, &nla, &buf, &creds);
if (rc < 0)
break;
nlmsg_for_each_msg(nlh, (struct nlmsghdr *) buf, rc, rem) {
if (rc <= 0 || cb_rc == NL_STOP)
break;
/* Check for callbacks */
msg = (struct nl_msg *)malloc(sizeof(struct nl_msg));
memset(msg, 0, sizeof(*msg));
msg->nm_nlh = nlh;
/* Check netlink message type */
switch (msg->nm_nlh->nlmsg_type) {
case NLMSG_ERROR: /* Used for ACK too */
/* Certainly we should be doing some
* checking here to make sure this
* message is intended for us */
nlme = nlmsg_data(msg->nm_nlh);
if (nlme->error == 0)
msg->nm_nlh->nlmsg_flags |= NLM_F_ACK;
rc = nlme->error;
cb_rc = cb->cb_err(&nla, nlme, cb->cb_err_arg);
nlme = NULL;
break;
case NLMSG_DONE:
done = 1;
case NLMSG_OVERRUN:
case NLMSG_NOOP:
default:
break;
};
for (i = 0; i <= NL_CB_TYPE_MAX; i++) {
if (cb->cb_set[i]) {
switch (i) {
case NL_CB_VALID:
if (rc > 0)
cb_rc = cb->cb_set[i](msg, cb->cb_args[i]);
break;
case NL_CB_FINISH:
if ((msg->nm_nlh->nlmsg_flags & NLM_F_MULTI) &&
(msg->nm_nlh->nlmsg_type & NLMSG_DONE))
cb_rc = cb->cb_set[i](msg, cb->cb_args[i]);
break;
case NL_CB_ACK:
if (msg->nm_nlh->nlmsg_flags & NLM_F_ACK)
cb_rc = cb->cb_set[i](msg, cb->cb_args[i]);
break;
default:
break;
}
}
}
free(msg);
if (done)
break;
}
free(buf);
buf = NULL;
if (done)
break;
} while (rc > 0 && cb_rc != NL_STOP);
success:
fail:
return rc;
}
/* Send raw data over netlink socket */
int nl_send(struct nl_sock *sk, struct nl_msg *msg)
{
struct nlmsghdr *nlh = nlmsg_hdr(msg);
struct iovec msg_iov;
/* Create IO vector with Netlink message */
msg_iov.iov_base = nlh;
msg_iov.iov_len = nlh->nlmsg_len;
return nl_send_iovec(sk, msg, &msg_iov, 1);
}
/* Send netlink message */
int nl_send_iovec(struct nl_sock *sk, struct nl_msg *msg,
struct iovec *iov, unsigned iovlen)
{
int rc;
/* Socket message */
struct msghdr mh = {
.msg_name = (void *) &sk->s_peer,
.msg_namelen = sizeof(sk->s_peer),
.msg_iov = iov,
.msg_iovlen = iovlen,
.msg_control = NULL,
.msg_controllen = 0,
.msg_flags = 0
};
/* Send message and verify sent */
rc = nl_sendmsg(sk, (struct nl_msg *) &mh, 0);
if (rc < 0)
fprintf(stderr, "Error sending netlink message: %d\n", errno);
return rc;
}
/* Send netlink message with control over sendmsg() message header */
int nl_sendmsg(struct nl_sock *sk, struct nl_msg *msg, struct msghdr *hdr)
{
return sendmsg(sk->s_fd, (struct msghdr *) msg, (int) hdr);
}
/* Create and connect netlink socket */
int nl_connect(struct nl_sock *sk, int protocol)
{
struct sockaddr addr;
socklen_t addrlen;
int rc;
/* Create RX socket */
sk->s_fd = socket(PF_NETLINK, SOCK_RAW, protocol);
if (sk->s_fd < 0)
return -errno;
/* Set size of RX and TX buffers */
if (nl_socket_set_buffer_size(sk, NL_BUFFER_SZ, NL_BUFFER_SZ) < 0)
return -errno;
/* Bind RX socket */
rc = bind(sk->s_fd, (struct sockaddr *)&sk->s_local, \
sizeof(sk->s_local));
if (rc < 0)
return -errno;
addrlen = sizeof(addr);
getsockname(sk->s_fd, &addr, &addrlen);
return 0;
}
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