netutils/netlib/netlib_getnbtab.c: Add support for retrieving a snapshot of the IPv6 neighbor table using Netlink sockets.

include/netutils/netlib.h

@@ -297,6 +297,12 @@ int netlib_ipv6adaptor(FAR const struct in6_addr *destipaddr,
 
 uint8_t netlib_ipv6netmask2prefix(FAR const uint16_t *mask);
 void netlib_prefix2ipv6netmask(uint8_t preflen, FAR struct in6_addr *netmask);
+#ifdef CONFIG_NETLINK_ROUTE
+struct neighbor_entry_s;
+ssize_t netlib_get_nbtable(FAR struct neighbor_entry_s *nbtab,
+                           unsigned int nentries);
+#endif
+
 #endif
 
 #ifdef CONFIG_NETDEV_WIRELESS_IOCTL

netutils/netlib/Makefile

@@ -1,7 +1,8 @@
 ############################################################################
 # apps/netutils/netlib/Makefile
 #
-#   Copyright (C) 2011-2012, 2014-2015, 2017 Gregory Nutt. All rights reserved.
+#   Copyright (C) 2011-2012, 2014-2015, 2017, 2019 Gregory Nutt. All
+#     rights reserved.
 #   Author: Gregory Nutt <gnutt@nuttx.org>
 #
 # Redistribution and use in source and binary forms, with or without
@@ -41,6 +42,7 @@ CSRCS  = netlib_ipv4addrconv.c netlib_ethaddrconv.c netlib_parsehttpurl.c
 CSRCS += netlib_setifstatus.c netlib_getifstatus.c
 
 # Generic URL parsing support
+
 ifeq ($(CONFIG_NETUTILS_NETLIB_GENERICURLPARSER),y)
 CSRCS += netlib_parseurl.c
 endif
@@ -54,6 +56,9 @@ CSRCS += netlib_getdripv4addr.c netlib_getipv4netmask.c
 CSRCS += netlib_ipv4adaptor.c
 ifeq ($(CONFIG_NET_ARP),y)
 CSRCS += netlib_getarp.c netlib_setarp.c netlib_delarp.c
+ifeq ($(CONFIG_NETLINK_ROUTE),y)
+CSRCS += netlib_getarptab.c
+endif
 endif
 ifeq ($(CONFIG_NETDB_DNSCLIENT),y)
 CSRCS += netlib_setipv4dnsaddr.c
@@ -74,6 +79,9 @@ endif
 ifeq ($(CONFIG_NET_ROUTE),y)
 CSRCS += netlib_ipv6route.c netlib_ipv6router.c
 endif
+ifeq ($(CONFIG_NETLINK_ROUTE),y)
+CSRCS += netlib_getnbtab.c
+endif
 endif
 
 # These require TCP support
@@ -84,14 +92,6 @@ CSRCS += netlib_server.c netlib_listenon.c
 endif
 endif
 
-# These require Netlink support
-
-ifeq ($(CONFIG_NETLINK_ROUTE),y)
-ifeq ($(CONFIG_NET_ARP),y)
-CSRCS += netlib_getarptab.c
-endif
-endif
-
 # These require wireless IOCTL support */
 
 ifeq ($(CONFIG_NETDEV_WIRELESS_IOCTL),y)

netutils/netlib/netlib_getarptab.c

@@ -96,7 +96,8 @@ struct netlib_recvfrom_response_s
  *
  ****************************************************************************/
 
-ssize_t netlib_get_arptable(FAR struct arp_entry_s *arptab, unsigned int nentries)
+ssize_t netlib_get_arptable(FAR struct arp_entry_s *arptab,
+                            unsigned int nentries)
 {
   FAR struct netlib_recvfrom_response_s *resp;
   struct netlib_sendto_request_s req;

netutils/netlib/netlib_getnbtab.c

@@ -0,0 +1,228 @@
+/****************************************************************************
+ * netutils/netlib/netlib_getntab.c
+ *
+ *   Copyright (C) 2019 Gregory Nutt. All rights reserved.
+ *   Author: Gregory Nutt <gnutt@nuttx.org>
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in
+ *    the documentation and/or other materials provided with the
+ *    distribution.
+ * 3. Neither the name NuttX nor the names of its contributors may be
+ *    used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+ * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
+ * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
+ * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
+ * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
+ * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
+ * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ *
+ ****************************************************************************/
+
+/****************************************************************************
+ * Included Files
+ ****************************************************************************/
+
+#include <nuttx/config.h>
+
+#include <sys/socket.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <string.h>
+#include <errno.h>
+#include <errno.h>
+
+#include <netpacket/netlink.h>
+
+#include <nuttx/net/neighbor.h>
+
+#include "netutils/netlib.h"
+
+#if defined(CONFIG_NET_IPv6) && defined(CONFIG_NETLINK_ROUTE)
+
+/****************************************************************************
+ * Private Types
+ ****************************************************************************/
+
+struct netlib_sendto_request_s
+{
+  struct nlmsghdr hdr;
+  struct ndmsg msg;
+};
+
+struct netlib_recvfrom_response_s
+{
+  struct nlmsghdr hdr;
+  struct ndmsg msg;
+  struct rtattr attr;
+  uint8_t data[1];
+};
+
+#define SIZEOF_NETLIB_RECVFROM_RESPONSE_S(n) \
+  (sizeof(struct netlib_recvfrom_response_s) + (n) - 1)
+
+/****************************************************************************
+ * Public Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Name: netlib_get_nbtable
+ *
+ * Description:
+ *   Attempt to read the entire Neighbor table into a buffer.
+ *
+ * Parameters:
+ *   nbtab    - The location to store the copy of the Neighbor table
+ *   nentries - The size of the provided 'nbtab' in number of entries each
+ *              of size sizeof(struct neighbor_entry_s)
+ *
+ * Return:
+ *   The number of Neighbor table entries read is returned on success; a
+ *   negated errno value is returned on failure.
+ *
+ ****************************************************************************/
+
+ssize_t netlib_get_nbtable(FAR struct neighbor_entry_s *nbtab,
+                           unsigned int nentries)
+{
+  FAR struct netlib_recvfrom_response_s *resp;
+  struct netlib_sendto_request_s req;
+  struct sockaddr_nl addr;
+  static unsigned int seqno = 0;
+  unsigned int thiseq;
+  unsigned int allocsize;
+  ssize_t nsent;
+  ssize_t nrecvd;
+  ssize_t paysize;
+  ssize_t maxsize;
+  int fd;
+  int ret;
+
+  /* Pre-allocate a buffer to hold the response */
+
+  maxsize   = CONFIG_NET_IPv6_NCONF_ENTRIES *
+              sizeof(struct neighbor_entry_s);
+  allocsize = SIZEOF_NETLIB_RECVFROM_RESPONSE_S(maxsize);
+  resp = (FAR struct netlib_recvfrom_response_s *)malloc(allocsize);
+  if (resp == NULL)
+    {
+      fprintf(stderr, "ERROR: Failed to allocate response buffer\n");
+      ret = -ENOMEM;
+      return EXIT_FAILURE;
+    }
+
+  /* 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);
+      ret = -errcode;
+      goto errout_with_resp;
+    }
+
+  /* Bind the socket so that we can use send() and receive() */
+
+  addr.nl_family = AF_NETLINK;
+  addr.nl_pad    = 0;
+  addr.nl_pid    = getpid();
+  addr.nl_groups = RTM_GETNEIGH;
+
+  ret = bind(fd, (FAR const struct sockaddr *)&addr,
+             sizeof( struct sockaddr_nl));
+  if (fd < 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 ndmsg));
+  req.hdr.nlmsg_flags = NLM_F_REQUEST | NLM_F_ROOT | NLM_F_REQUEST;
+  req.hdr.nlmsg_seq   = thiseq;
+  req.hdr.nlmsg_type  = RTM_GETNEIGH;
+  req.msg.ndm_family  = AF_INET6;
+
+  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 */
+
+  nrecvd = recv(fd, resp, allocsize, 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 Neighbor table data 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 Neighbor table data to the caller's buffer */
+
+  paysize = resp->attr.rta_len;
+  if (paysize > maxsize)
+    {
+      paysize = maxsize;
+    }
+
+  memcpy(nbtab, resp->data, paysize);
+  ret = paysize / sizeof(struct neighbor_entry_s);
+
+errout_with_socket:
+  close(fd);
+
+errout_with_resp:
+  free(resp);
+  return ret;
+}
+
+#endif /* CONFIG_NET_IPv6 && CONFIG_NETLINK_ROUTE */