/****************************************************************************
* apps/netutils/netlib/netlib_getdevs.c
*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership. The
* ASF licenses this file to you 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.
*
****************************************************************************/
/****************************************************************************
* Included Files
****************************************************************************/
#include <nuttx/config.h>
#include <sys/socket.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <string.h>
#include <errno.h>
#include <netpacket/netlink.h>
#include "netutils/netlib.h"
#ifdef CONFIG_NETLINK_ROUTE
/****************************************************************************
* Private Types
****************************************************************************/
struct netlib_sendto_request_s
{
struct nlmsghdr hdr;
struct rtgenmsg gen;
};
struct netlib_recvfrom_response_s
{
struct nlmsghdr hdr;
struct ifinfomsg iface;
struct rtattr attr;
uint8_t data[IFNAMSIZ]; /* IFLA_IFNAME is the only attribute
* supported */
};
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: netlib_get_devices
*
* Description:
* Return a list of all active network devices (devices in the DOWN state
* are not reported).
*
* Parameters:
* devlist - The location to store the list of devices.
* nentries - The size of the provided 'devlist' in number of entries each
* of size sizeof(struct netlib_device_s)
* family - Address family. See AF_* definitions in sys/socket.h. Use
* AF_PACKET to return devices for all address families.
*
* Return:
* The number of device entries read is returned on success; a negated
* errno value is returned on failure.
*
****************************************************************************/
ssize_t netlib_get_devices(FAR struct netlib_device_s *devlist,
unsigned int nentries, sa_family_t family)
{
struct netlib_sendto_request_s req;
struct netlib_recvfrom_response_s resp;
struct sockaddr_nl addr;
static unsigned int seqno = 0;
unsigned int thiseq;
ssize_t nsent;
ssize_t nrecvd;
size_t ncopied = 0;
pid_t pid;
bool enddump;
int fd;
int ret;
/* Create a NetLink socket with NETLINK_ROUTE protocol */
fd = socket(PF_NETLINK, SOCK_DGRAM, NETLINK_ROUTE);
if (fd < 0)
{
int errcode = errno;
fprintf(stderr, "ERROR: socket() failed: %d\n", errcode);
return -errcode;
}
/* Bind the socket so that we can use send() and receive() */
pid = gettid();
addr.nl_family = AF_NETLINK;
addr.nl_pad = 0;
addr.nl_pid = pid;
addr.nl_groups = 0;
ret = bind(fd, (FAR const struct sockaddr *)&addr,
sizeof(struct sockaddr_nl));
if (ret < 0)
{
int errcode = errno;
fprintf(stderr, "ERROR: bind() failed: %d\n", errcode);
ret = -errcode;
goto errout_with_socket;
}
/* Initialize the request */
thiseq = ++seqno;
memset(&req, 0, sizeof(req));
req.hdr.nlmsg_len = NLMSG_LENGTH(sizeof(struct rtgenmsg));
req.hdr.nlmsg_flags = NLM_F_REQUEST | NLM_F_DUMP;
req.hdr.nlmsg_seq = thiseq;
req.hdr.nlmsg_type = RTM_GETLINK;
req.hdr.nlmsg_pid = pid;
req.gen.rtgen_family = family;
nsent = send(fd, &req, req.hdr.nlmsg_len, 0);
if (nsent < 0)
{
int errcode = errno;
fprintf(stderr, "ERROR: send() failed: %d\n", errcode);
ret = -errcode;
goto errout_with_socket;
}
/* Read the response(s) */
for (enddump = false; !enddump; )
{
/* Receive the next device response */
nrecvd = recv(fd, &resp, sizeof(struct netlib_recvfrom_response_s), 0);
if (nrecvd < 0)
{
int errcode = errno;
fprintf(stderr, "ERROR: recv() failed: %d\n", errcode);
ret = -errcode;
goto errout_with_socket;
}
/* Verify the data and transfer the device list to the caller */
if (resp.hdr.nlmsg_len < sizeof(struct nlmsghdr) ||
resp.hdr.nlmsg_len != nrecvd)
{
fprintf(stderr, "ERROR: Bad message\n");
ret = -EIO;
goto errout_with_socket;
}
/* The sequence number in the response should match the sequence
* number in the request (since we created the socket, this should
* always be true).
*/
if (resp.hdr.nlmsg_seq != thiseq)
{
fprintf(stderr, "ERROR: Bad sequence number in response\n");
ret = -EIO;
goto errout_with_socket;
}
/* Copy the device list to the caller's buffer */
switch (resp.hdr.nlmsg_type)
{
/* NLMSG_DONE means that the entire list of devices has been
* returned
*/
case NLMSG_DONE:
enddump = true;
break;
/* RTM_NEWLINK provides information about one device */
case RTM_NEWLINK:
{
FAR struct rtattr *attr;
unsigned int attrlen;
/* Verify the expected message length */
if (nrecvd != sizeof(struct netlib_recvfrom_response_s))
{
fprintf(stderr, "ERROR: Bad massage size: %ld\n",
(long)nrecvd);
goto errout_with_socket;
}
/* Decode the response */
attr = &resp.attr;
attrlen = resp.hdr.nlmsg_len - sizeof(struct nlmsghdr) -
sizeof(struct ifinfomsg);
for (; RTA_OK(attr, attrlen); attr = RTA_NEXT(attr, attrlen))
{
switch (attr->rta_type)
{
case IFLA_IFNAME:
if (ncopied < nentries)
{
#ifdef CONFIG_NETDEV_IFINDEX
FAR struct ifinfomsg *iface = &resp.iface;
devlist[ncopied].ifindex = iface->ifi_index;
#endif
strlcpy(devlist[ncopied].ifname,
(FAR char *)RTA_DATA(attr), IFNAMSIZ);
ncopied++;
}
break;
default:
break;
}
}
}
break;
default:
fprintf(stderr, "ERROR: Message type %u, length %lu\n",
resp.hdr.nlmsg_type, (unsigned long)resp.hdr.nlmsg_len);
ret = -EIO;
goto errout_with_socket;
}
}
close(fd);
return ncopied;
errout_with_socket:
close(fd);
return ret;
}
#endif /* CONFIG_NETLINK_ROUTE */