[BACKPORT] Ethernet : changes made to support ethernet (#27)

 - unicast
 - broadcast
 - multicast

include/nuttx/net/ip.h

@@ -508,6 +508,46 @@ bool net_ipv6addr_maskcmp(const net_ipv6addr_t addr1,
                           const net_ipv6addr_t mask);
 #endif
 
+/****************************************************************************
+ * Name: net_ipv4addr_broadcast
+ *
+ * Description:
+ *    Mask out the network part of an IP address, given the address and
+ *    the netmask.
+ *
+ *    Example:
+ *
+ *     in_addr_t ipaddr;
+ *     in_addr_t netmask;
+ *     bool isbroadcast;
+ *
+ *     net_ipaddr(&netmask, 255,255,255,0);
+ *     net_ipaddr(&ipaddr, 192,16,1,255);
+ *     isbroadcast = net_ipv4addr_broadcast(ipaddr, netmask);
+ *
+ *   Will return isboadcast == true.
+ *
+ *     net_ipaddr(&ipaddr, 192,16,1,2);
+ *     isbroadcast = net_ipv4addr_broadcast(ipaddr, netmask);
+ *
+ *   Will return isboadcast == false.
+ *
+ *   NOTES:
+ *   1. This function does not check for the broadcast address
+ *      255.255.255.255.  That must be performed as a seperate check.
+ *   2. You must also separately check if the ipaddress lies on the sub-net
+ *      using, perhaps, net_ipv4addr_maskcmp().
+ *
+ * Input Parameters:
+ *   addr - The IPv4 address to check
+ *   mask - The network mask
+ *
+ ****************************************************************************/
+
+#define net_ipv4addr_broadcast(addr, mask) \
+   (((in_addr_t)(addr) & ~(in_addr_t)(mask)) == \
+    ((in_addr_t)(0xffffffff) & ~(in_addr_t)(mask)))
+
 /****************************************************************************
  * Name: net_ipv6addr_prefixcmp
  *
@@ -587,36 +627,6 @@ bool net_ipv6addr_maskcmp(const net_ipv6addr_t addr1,
 
 #define net_is_addr_linklocal(a) ((a)[0] == HTONS(0xfe80))
 
-/****************************************************************************
- * Name: net_ipaddr_mask
- *
- * Description:
- *    Mask out the network part of an IP address, given the address and
- *    the netmask.
- *
- *    Example:
- *
- *     in_addr_t ipaddr1, ipaddr2, netmask;
- *
- *     net_ipaddr(&ipaddr1, 192,16,1,2);
- *     net_ipaddr(&netmask, 255,255,255,0);
- *     net_ipaddr_mask(&ipaddr2, &ipaddr1, &netmask);
- *
- *   In the example above, the variable "ipaddr2" will contain the IP
- *   address 192.168.1.0.
- *
- * Input Parameters:
- *   dest Where the result is to be placed.
- *   src The IP address.
- *   mask The netmask.
- *
- ****************************************************************************/
-
-#define net_ipaddr_mask(dest, src, mask) \
-  do { \
-    (in_addr_t)(dest) = (in_addr_t)(src) & (in_addr_t)(mask); \
-  } while (0)
-
 #undef EXTERN
 #ifdef __cplusplus
 }

libc/net/Make.defs

@@ -36,7 +36,8 @@
 # Add the networking C files to the build
 
 CSRCS += lib_addrconfig.c lib_etherntoa.c lib_htons.c lib_htonl.c
-CSRCS += lib_inetaddr.c lib_inetntoa.c lib_inetntop.c lib_inetpton.c
+CSRCS += lib_inetaddr.c lib_inetaton.c lib_inetntoa.c
+CSRCS += lib_inetntop.c lib_inetpton.c
 
 ifeq ($(CONFIG_NET),y)
 CSRCS += lib_shutdown.c

libc/net/lib_inetaton.c

@@ -0,0 +1,125 @@
+/****************************************************************************
+ * libc/net/lib_inetaton
+ *
+ *   Copyright (C) 2018 Gregory Nutt. All rights reserved.
+ *   Author: Juha Niskanen <juha.niskanen@haltian.com>
+ *
+ * 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 <stdint.h>
+#include <arpa/inet.h>
+
+/****************************************************************************
+ * Public Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Name: inet_aton
+ *
+ * Description:
+ *   The inet_aton() function converts the string pointed to by cp, in the
+ *   standard IPv4 dotted decimal notation, to an integer value suitable for
+ *   use as an Internet address.
+ *
+ * Note:
+ *   inet_aton() returns nonzero if the address is valid, zero if not.
+ *   Therefore macros OK and ERROR are not used here.
+ *
+ ****************************************************************************/
+
+int inet_aton(FAR const char *cp, FAR struct in_addr *inp)
+{
+  int dots = 0;
+  uint32_t num = 0;
+  uint32_t addr = 0;
+  int c;
+
+  do
+    {
+      c = *cp;
+
+      switch (c)
+        {
+          case '0':
+          case '1':
+          case '2':
+          case '3':
+          case '4':
+          case '5':
+          case '6':
+          case '7':
+          case '8':
+          case '9':
+            num = 10 * num + (c - '0');
+            break;
+
+          case '.':
+            dots++;
+            if (dots > 3)
+              {
+                return 0;
+              }
+
+            /* no break */
+
+          case '\0':
+            if (num > 255)
+              {
+                return 0;
+              }
+
+            addr = addr << 8 | num;
+            num = 0;
+            break;
+
+          default:
+            return 0;
+        }
+    }
+  while (*cp++);
+
+  /* Normalize it */
+
+  if (dots < 3)
+    {
+      addr <<= 8 * (3 - dots);
+    }
+
+  if (inp)
+    {
+      inp->s_addr = HTONL(addr);
+    }
+
+  return 1;
+}

net/arp/arp_out.c

@@ -169,6 +169,7 @@ void arp_out(FAR struct net_driver_s *dev)
   if (net_ipv4addr_hdrcmp(pip->eh_destipaddr, g_broadcast_ipaddr))
     {
       memcpy(peth->dest, g_broadcast_ethaddr.ether_addr_octet, ETHER_ADDR_LEN);
+      goto finish_header;
     }
 
 #ifdef CONFIG_NET_IGMP
@@ -181,74 +182,94 @@ void arp_out(FAR struct net_driver_s *dev)
    *   addresses=0xff (ff00::/8.)
    */
 
-  else if (NTOHS(pip->eh_destipaddr[0]) >= 0xe000 &&
-           NTOHS(pip->eh_destipaddr[0]) <= 0xefff)
+  if (NTOHS(pip->eh_destipaddr[0]) >= 0xe000 &&
+      NTOHS(pip->eh_destipaddr[0]) <= 0xefff)
     {
       /* Build the well-known IPv4 IGMP Ethernet address.  The first
        * three bytes are fixed; the final three variable come from the
-       * last three bytes of the IP address.
+       * last three bytes of the IPv4 address (network order).
+       *
+       * Address range : 01:00:5e:00:00:00 to 01:00:5e:7f:ff:ff
        */
 
-      FAR const uint8_t *ip = ((FAR uint8_t *)pip->eh_destipaddr) + 1;
-      memcpy(peth->dest,  g_multicast_ethaddr, 3);
-      memcpy(&peth->dest[3], ip, 3);
+      FAR const uint8_t *ip = (FAR uint8_t *)pip->eh_destipaddr;
+
+      peth->dest[0] = g_multicast_ethaddr[0];
+      peth->dest[1] = g_multicast_ethaddr[1];
+      peth->dest[2] = g_multicast_ethaddr[2];
+      peth->dest[3] = ip[1] & 0x7f;
+      peth->dest[4] = ip[2];
+      peth->dest[5] = ip[3];
+
+      goto finish_header;
     }
 #endif
-  else
-    {
-      /* Check if the destination address is on the local network. */
 
-      destipaddr = net_ip4addr_conv32(pip->eh_destipaddr);
-      if (!net_ipv4addr_maskcmp(destipaddr, dev->d_ipaddr, dev->d_netmask))
-        {
-          /* Destination address is not on the local network */
+  /* Check if the destination address is on the local network. */
+
+  destipaddr = net_ip4addr_conv32(pip->eh_destipaddr);
+  if (!net_ipv4addr_maskcmp(destipaddr, dev->d_ipaddr, dev->d_netmask))
+    {
+      /* Destination address is not on the local network */
 
 #ifdef CONFIG_NET_ROUTE
-          /* We have a routing table.. find the correct router to use in
-           * this case (or, as a fall-back, use the device's default router
-           * address).  We will use the router IP address instead of the
-           * destination address when determining the MAC address.
-           */
+      /* We have a routing table.. find the correct router to use in
+       * this case (or, as a fall-back, use the device's default router
+       * address).  We will use the router IP address instead of the
+       * destination address when determining the MAC address.
+       */
 
-          netdev_ipv4_router(dev, destipaddr, &ipaddr);
+      netdev_ipv4_router(dev, destipaddr, &ipaddr);
 #else
-          /* Use the device's default router IP address instead of the
-           * destination address when determining the MAC address.
-           */
+      /* Use the device's default router IP address instead of the
+       * destination address when determining the MAC address.
+       */
 
-          net_ipv4addr_copy(ipaddr, dev->d_draddr);
+      net_ipv4addr_copy(ipaddr, dev->d_draddr);
 #endif
-        }
-      else
-        {
-          /* Else, we use the destination IP address. */
+    }
+
+  /* The destination address is on the local network.  Check if it is
+   * the sub-net broadcast address.
+   */
 
-          net_ipv4addr_copy(ipaddr, destipaddr);
-        }
+  else if (net_ipv4addr_broadcast(destipaddr, dev->d_netmask))
+    {
+      /* Yes.. then we won't need to know the destination MAC address */
 
-      /* Check if we already have this destination address in the ARP table */
+      memcpy(peth->dest, g_broadcast_ethaddr.ether_addr_octet, ETHER_ADDR_LEN);
+      goto finish_header;
+    }
+  else
+    {
+      /* Else, we use the destination IP address. */
 
-      tabptr = arp_find(ipaddr);
-      if (!tabptr)
-        {
-           ninfo("ARP request for IP %08lx\n", (unsigned long)ipaddr);
+      net_ipv4addr_copy(ipaddr, destipaddr);
+    }
 
-          /* The destination address was not in our ARP table, so we
-           * overwrite the IP packet with an ARP request.
-           */
+  /* Check if we already have this destination address in the ARP table */
 
-          arp_format(dev, ipaddr);
-          arp_dump(ARPBUF);
-          return;
-        }
+  tabptr = arp_find(ipaddr);
+  if (tabptr == NULL)
+    {
+      ninfo("ARP request for IP %08lx\n", (unsigned long)ipaddr);
 
-      /* Build an Ethernet header. */
+      /* The destination address was not in our ARP table, so we overwrite
+       * the IP packet with an ARP request.
+       */
 
-      memcpy(peth->dest, tabptr->at_ethaddr.ether_addr_octet, ETHER_ADDR_LEN);
+      arp_format(dev, ipaddr);
+      arp_dump(ARPBUF);
+      return;
     }
 
+  /* Build an Ethernet header. */
+
+  memcpy(peth->dest, tabptr->at_ethaddr.ether_addr_octet, ETHER_ADDR_LEN);
+
   /* Finish populating the Ethernet header */
 
+finish_header:
   memcpy(peth->src, dev->d_mac.ether.ether_addr_octet, ETHER_ADDR_LEN);
   peth->type  = HTONS(ETHTYPE_IP);
   dev->d_len += ETH_HDRLEN;

net/arp/arp_send.c

@@ -268,6 +268,17 @@ int arp_send(in_addr_t ipaddr)
       ipaddr = dripaddr;
     }
 
+  /* The destination address is on the local network.  Check if it is
+   * the sub-net broadcast address.
+   */
+
+  else if (net_ipv4addr_broadcast(ipaddr, dev->d_netmask))
+    {
+      /* Yes.. We don't need to send the ARP request */
+
+      return OK;
+    }
+
   /* Allocate resources to receive a callback.  This and the following
    * initialization is performed with the network lock because we don't
    * want anything to happen until we are ready.