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/*
* lxc: linux Container library
*
* (C) Copyright IBM Corp. 2007, 2008
*
* Authors:
* Daniel Lezcano <dlezcano at fr.ibm.com>
*
* 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; either
* version 2.1 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
#include <sys/socket.h>
#include <string.h>
#include <stdio.h>
#include <time.h>
#include <unistd.h>
#include <errno.h>
#include <stdlib.h>
#include <linux/netlink.h>
#include <linux/rtnetlink.h>
#include "nl.h"
#define NLMSG_TAIL(nmsg) \
((struct rtattr *) (((void *) (nmsg)) + NLMSG_ALIGN((nmsg)->nlmsg_len)))
extern size_t nlmsg_len(const struct nlmsg *nlmsg)
{
return nlmsg->nlmsghdr.nlmsg_len - NLMSG_HDRLEN;
}
extern void *nlmsg_data(struct nlmsg *nlmsg)
{
char *data = ((char *)nlmsg) + NLMSG_ALIGN(sizeof(struct nlmsghdr));
if (!nlmsg_len(nlmsg))
return NULL;
return data;
}
static int nla_put(struct nlmsg *nlmsg, int attr,
const void *data, size_t len)
{
struct rtattr *rta;
size_t rtalen = RTA_LENGTH(len);
rta = NLMSG_TAIL(&nlmsg->nlmsghdr);
rta->rta_type = attr;
rta->rta_len = rtalen;
memcpy(RTA_DATA(rta), data, len);
nlmsg->nlmsghdr.nlmsg_len =
NLMSG_ALIGN(nlmsg->nlmsghdr.nlmsg_len) + RTA_ALIGN(rtalen);
return 0;
}
extern int nla_put_buffer(struct nlmsg *nlmsg, int attr,
const void *data, size_t size)
{
return nla_put(nlmsg, attr, data, size);
}
extern int nla_put_string(struct nlmsg *nlmsg, int attr, const char *string)
{
return nla_put(nlmsg, attr, string, strlen(string) + 1);
}
extern int nla_put_u32(struct nlmsg *nlmsg, int attr, int value)
{
return nla_put(nlmsg, attr, &value, sizeof(value));
}
extern int nla_put_u16(struct nlmsg *nlmsg, int attr, ushort value)
{
return nla_put(nlmsg, attr, &value, 2);
}
extern int nla_put_attr(struct nlmsg *nlmsg, int attr)
{
return nla_put(nlmsg, attr, NULL, 0);
}
struct rtattr *nla_begin_nested(struct nlmsg *nlmsg, int attr)
{
struct rtattr *rtattr = NLMSG_TAIL(&nlmsg->nlmsghdr);
if (nla_put_attr(nlmsg, attr))
return NULL;
return rtattr;
}
void nla_end_nested(struct nlmsg *nlmsg, struct rtattr *attr)
{
attr->rta_len = (void *)NLMSG_TAIL(&nlmsg->nlmsghdr) - (void *)attr;
}
extern struct nlmsg *nlmsg_alloc(size_t size)
{
struct nlmsg *nlmsg;
size_t len = NLMSG_ALIGN(size) + NLMSG_ALIGN(sizeof(struct nlmsghdr *));
nlmsg = (struct nlmsg *)malloc(len);
if (!nlmsg)
return NULL;
memset(nlmsg, 0, len);
nlmsg->nlmsghdr.nlmsg_len = NLMSG_ALIGN(size);
return nlmsg;
}
extern void nlmsg_free(struct nlmsg *nlmsg)
{
free(nlmsg);
}
extern int netlink_rcv(struct nl_handler *handler, struct nlmsg *answer)
{
int ret;
struct sockaddr_nl nladdr;
struct iovec iov = {
.iov_base = answer,
.iov_len = answer->nlmsghdr.nlmsg_len,
};
struct msghdr msg = {
.msg_name = &nladdr,
.msg_namelen = sizeof(nladdr),
.msg_iov = &iov,
.msg_iovlen = 1,
};
memset(&nladdr, 0, sizeof(nladdr));
nladdr.nl_family = AF_NETLINK;
nladdr.nl_pid = 0;
nladdr.nl_groups = 0;
again:
ret = recvmsg(handler->fd, &msg, 0);
if (ret < 0) {
if (errno == EINTR)
goto again;
return -errno;
}
if (!ret)
return 0;
if (msg.msg_flags & MSG_TRUNC &&
ret == answer->nlmsghdr.nlmsg_len)
return -EMSGSIZE;
return ret;
}
extern int netlink_send(struct nl_handler *handler, struct nlmsg *nlmsg)
{
struct sockaddr_nl nladdr;
struct iovec iov = {
.iov_base = (void*)nlmsg,
.iov_len = nlmsg->nlmsghdr.nlmsg_len,
};
struct msghdr msg = {
.msg_name = &nladdr,
.msg_namelen = sizeof(nladdr),
.msg_iov = &iov,
.msg_iovlen = 1,
};
int ret;
memset(&nladdr, 0, sizeof(nladdr));
nladdr.nl_family = AF_NETLINK;
nladdr.nl_pid = 0;
nladdr.nl_groups = 0;
ret = sendmsg(handler->fd, &msg, 0);
if (ret < 0)
return -errno;
return ret;
}
#ifndef NLMSG_ERROR
#define NLMSG_ERROR 0x2
#endif
extern int netlink_transaction(struct nl_handler *handler,
struct nlmsg *request, struct nlmsg *answer)
{
int ret;
ret = netlink_send(handler, request);
if (ret < 0)
return ret;
ret = netlink_rcv(handler, answer);
if (ret < 0)
return ret;
if (answer->nlmsghdr.nlmsg_type == NLMSG_ERROR) {
struct nlmsgerr *err = (struct nlmsgerr*)NLMSG_DATA(answer);
return err->error;
}
return 0;
}
extern int netlink_open(struct nl_handler *handler, int protocol)
{
socklen_t socklen;
int sndbuf = 32768;
int rcvbuf = 32768;
memset(handler, 0, sizeof(*handler));
handler->fd = socket(AF_NETLINK, SOCK_RAW, protocol);
if (handler->fd < 0)
return -errno;
if (setsockopt(handler->fd, SOL_SOCKET, SO_SNDBUF,
&sndbuf, sizeof(sndbuf)) < 0)
return -errno;
if (setsockopt(handler->fd, SOL_SOCKET, SO_RCVBUF,
&rcvbuf,sizeof(rcvbuf)) < 0)
return -errno;
memset(&handler->local, 0, sizeof(handler->local));
handler->local.nl_family = AF_NETLINK;
handler->local.nl_groups = 0;
if (bind(handler->fd, (struct sockaddr*)&handler->local,
sizeof(handler->local)) < 0)
return -errno;
socklen = sizeof(handler->local);
if (getsockname(handler->fd, (struct sockaddr*)&handler->local,
&socklen) < 0)
return -errno;
if (socklen != sizeof(handler->local))
return -EINVAL;
if (handler->local.nl_family != AF_NETLINK)
return -EINVAL;
handler->seq = time(NULL);
return 0;
}
extern int netlink_close(struct nl_handler *handler)
{
close(handler->fd);
handler->fd = -1;
return 0;
}
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