342 lines
10 KiB
C
342 lines
10 KiB
C
/****************************************************************************
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* netutils/netlib/netlib_getroute.c
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*
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* Copyright (C) 2019 Gregory Nutt. All rights reserved.
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* Author: Gregory Nutt <gnutt@nuttx.org>
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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*
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in
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* the documentation and/or other materials provided with the
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* distribution.
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* 3. Neither the name NuttX nor the names of its contributors may be
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* used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
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* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
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* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
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* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
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* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
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* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
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* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGE.
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*
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****************************************************************************/
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/****************************************************************************
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* Included Files
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****************************************************************************/
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#include <nuttx/config.h>
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#include <sys/socket.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <unistd.h>
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#include <string.h>
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#include <errno.h>
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#include <net/route.h>
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#include <netpacket/netlink.h>
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#include "netutils/netlib.h"
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#if defined(CONFIG_NETLINK_ROUTE) && defined(CONFIG_NET_ROUTE)
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/****************************************************************************
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* Pre-processor definitions
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****************************************************************************/
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#define RXBUFFER_SIZE 64
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/****************************************************************************
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* Private Types
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****************************************************************************/
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struct netlib_sendto_request_s
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{
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struct nlmsghdr hdr;
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struct rtgenmsg gen;
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};
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struct netlib_recvfrom_response_s
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{
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struct nlmsghdr hdr;
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struct rtmsg rte;
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struct rtattr attr;
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/* Attribute data and additional attributes follow */
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};
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/****************************************************************************
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* Private Functions
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****************************************************************************/
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static int copy_address(FAR struct sockaddr_storage *dest, FAR void *src,
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unsigned int addrlen, unsigned int maxaddr,
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sa_family_t family)
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{
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DEBUGASSERT(addrlen <= maxaddr);
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if (addrlen > maxaddr)
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{
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fprintf(stderr, "ERROR: Bad address length: %u\n", addrlen);
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return -EIO;
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}
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dest->ss_family = family;
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memcpy(dest->ss_data, src, addrlen);
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return OK;
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}
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/****************************************************************************
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* Public Functions
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****************************************************************************/
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/****************************************************************************
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* Name: netlib_get_route
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*
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* Description:
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* Return a snapshot of the routing table for the selected address family.
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*
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* Parameters:
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* rtelist - The location to store the list of devices.
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* nentries - The size of the provided 'rtelist' in number of entries.
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* The size of one entry is given by sizeof(struct rtentry);
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* family - Address family. See AF_* definitions in sys/socket.h.
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*
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* Return:
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* The number of routing table entries read is returned on success; a
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* negated errno value is returned on failure.
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*
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****************************************************************************/
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ssize_t netlib_get_route(FAR struct rtentry *rtelist,
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unsigned int nentries, sa_family_t family)
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{
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struct netlib_sendto_request_s req;
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struct sockaddr_nl addr;
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static unsigned int seqno = 0;
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unsigned int thiseq;
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unsigned int maxaddr;
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ssize_t nsent;
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ssize_t nrecvd;
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size_t ncopied = 0;
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pid_t pid;
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bool enddump;
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int fd;
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int ret;
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union
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{
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char rxbuffer[RXBUFFER_SIZE];
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struct netlib_recvfrom_response_s resp;
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} u;
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/* Create a NetLink socket with NETLINK_ROUTE protocol */
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fd = socket(PF_NETLINK, SOCK_DGRAM, NETLINK_ROUTE);
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if (fd < 0)
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{
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int errcode = errno;
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fprintf(stderr, "ERROR: socket() failed: %d\n", errcode);
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return -errcode;
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}
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/* Bind the socket so that we can use send() and receive() */
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pid = getpid();
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addr.nl_family = AF_NETLINK;
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addr.nl_pad = 0;
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addr.nl_pid = pid;
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addr.nl_groups = RTM_GETROUTE;
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ret = bind(fd, (FAR const struct sockaddr *)&addr,
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sizeof( struct sockaddr_nl));
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if (ret < 0)
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{
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int errcode = errno;
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fprintf(stderr, "ERROR: bind() failed: %d\n", errcode);
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ret = -errcode;
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goto errout_with_socket;
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}
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/* Initialize the request */
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thiseq = ++seqno;
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memset(&req, 0, sizeof(req));
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req.hdr.nlmsg_len = NLMSG_LENGTH(sizeof(struct rtgenmsg));
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req.hdr.nlmsg_flags = NLM_F_REQUEST | NLM_F_DUMP;
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req.hdr.nlmsg_seq = thiseq;
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req.hdr.nlmsg_type = RTM_GETROUTE;
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req.hdr.nlmsg_pid = pid;
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req.gen.rtgen_family = family;
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nsent = send(fd, &req, req.hdr.nlmsg_len, 0);
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if (nsent < 0)
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{
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int errcode = errno;
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fprintf(stderr, "ERROR: send() failed: %d\n", errcode);
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ret = -errcode;
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goto errout_with_socket;
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}
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/* Read the response(s) */
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maxaddr = sizeof(struct sockaddr_storage) - sizeof(sa_family_t);
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for (enddump = false; !enddump; )
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{
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/* Receive the next device response */
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nrecvd = recv(fd, &u.rxbuffer, RXBUFFER_SIZE, 0);
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if (nrecvd < 0)
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{
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int errcode = errno;
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fprintf(stderr, "ERROR: recv() failed: %d\n", errcode);
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ret = -errcode;
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goto errout_with_socket;
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}
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/* Verify the data and transfer the device list to the caller */
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if (u.resp.hdr.nlmsg_len < sizeof(struct nlmsghdr) ||
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u.resp.hdr.nlmsg_len != nrecvd)
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{
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fprintf(stderr, "ERROR: Bad message\n");
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ret = -EIO;
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goto errout_with_socket;
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}
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/* The sequence number in the response should match the sequence
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* number in the request (since we created the socket, this should
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* always be true).
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*/
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if (u.resp.hdr.nlmsg_seq != thiseq)
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{
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fprintf(stderr, "ERROR: Bad sequence number in response\n");
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ret = -EIO;
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goto errout_with_socket;
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}
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/* This should be a routing table response */
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if (u.resp.rte.rtm_table != RT_TABLE_MAIN)
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{
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fprintf(stderr, "ERROR: Not a routing table response\n");
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ret = -EIO;
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goto errout_with_socket;
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}
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/* Copy the routing table entry to the caller's buffer */
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switch (u.resp.hdr.nlmsg_type)
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{
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case NLMSG_DONE:
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enddump = true;
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break;
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case RTM_NEWLINK:
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break; /* Ignore any link information */
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case RTM_NEWROUTE:
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{
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FAR struct rtentry *dest;
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FAR struct rtattr *attr;
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unsigned int paylen;
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/* Verify the expected message length */
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if (nrecvd <= sizeof(struct netlib_recvfrom_response_s) ||
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u.resp.rte.rtm_family != family)
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{
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fprintf(stderr, "ERROR: Bad massage size: %ld\n", (long)nrecvd);
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goto errout_with_socket;
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}
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/* Decode the response */
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dest = &rtelist[ncopied];
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memset(dest, 0, sizeof(struct rtentry));
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attr = &u.resp.attr;
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paylen = u.resp.hdr.nlmsg_len - sizeof(struct nlmsghdr) -
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sizeof(struct rtmsg);
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for (; RTA_OK(attr, paylen); attr = RTA_NEXT(attr, paylen))
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{
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unsigned int attrlen = RTA_PAYLOAD(attr);
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switch (attr->rta_type)
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{
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case RTA_DST: /* The destination network */
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ret = copy_address(&dest->rt_dst, RTA_DATA(attr),
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attrlen, maxaddr, family);
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if (ret < 0)
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{
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goto errout_with_socket;
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}
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break;
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case RTA_SRC: /* The source address mask */
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break;
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case RTA_GENMASK: /* The network address mask */
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ret = copy_address(&dest->rt_genmask, RTA_DATA(attr),
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attrlen, maxaddr, family);
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if (ret < 0)
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{
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goto errout_with_socket;
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}
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break;
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case RTA_GATEWAY: /* Route packets via this router */
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ret = copy_address(&dest->rt_gateway, RTA_DATA(attr),
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attrlen, maxaddr, family);
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if (ret < 0)
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{
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goto errout_with_socket;
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}
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break;
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default:
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break;
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}
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}
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ncopied++;
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}
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break;
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default:
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fprintf(stderr, "ERROR: Message type %u, length %lu\n",
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u.resp.hdr.nlmsg_type, (unsigned long)u.resp.hdr.nlmsg_len);
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ret = -EIO;
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goto errout_with_socket;
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}
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}
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close(fd);
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return ncopied;
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errout_with_socket:
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close(fd);
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return ret;
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}
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#endif /* CONFIG_NETLINK_ROUTE && CONFIG_NET_ROUTE */
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