Added from uip-0.9/uip/uip_arp.[ch]

src/proto/uip/uip_arp.c

@@ -0,0 +1,423 @@
+/**
+ * \addtogroup uip
+ * @{
+ */
+
+/**
+ * \defgroup uiparp uIP Address Resolution Protocol
+ * @{
+ * 
+ * The Address Resolution Protocol ARP is used for mapping between IP
+ * addresses and link level addresses such as the Ethernet MAC
+ * addresses. ARP uses broadcast queries to ask for the link level
+ * address of a known IP address and the host which is configured with
+ * the IP address for which the query was meant, will respond with its
+ * link level address.
+ *
+ * \note This ARP implementation only supports Ethernet.
+ */
+ 
+/**
+ * \file
+ * Implementation of the ARP Address Resolution Protocol.
+ * \author Adam Dunkels <adam@dunkels.com>
+ *
+ */
+
+/*
+ * Copyright (c) 2001-2003, Adam Dunkels.
+ * All rights reserved. 
+ *
+ * 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. The name of the author may not be used to endorse or promote
+ *    products derived from this software without specific prior
+ *    written permission.  
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 AUTHOR 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.  
+ *
+ * This file is part of the uIP TCP/IP stack.
+ *
+ * $Id$
+ *
+ */
+
+
+#include "uip_arp.h"
+
+#include <string.h>
+
+struct arp_hdr {
+  struct uip_eth_hdr ethhdr;
+  u16_t hwtype;
+  u16_t protocol;
+  u8_t hwlen;
+  u8_t protolen;
+  u16_t opcode;
+  struct uip_eth_addr shwaddr;
+  u16_t sipaddr[2];
+  struct uip_eth_addr dhwaddr;
+  u16_t dipaddr[2]; 
+};
+
+struct ethip_hdr {
+  struct uip_eth_hdr ethhdr;
+  /* IP header. */
+  u8_t vhl,
+    tos,          
+    len[2],       
+    ipid[2],        
+    ipoffset[2],  
+    ttl,          
+    proto;     
+  u16_t ipchksum;
+  u16_t srcipaddr[2], 
+    destipaddr[2];
+};
+
+#define ARP_REQUEST 1
+#define ARP_REPLY   2
+
+#define ARP_HWTYPE_ETH 1
+
+struct arp_entry {
+  u16_t ipaddr[2];
+  struct uip_eth_addr ethaddr;
+  u8_t time;
+};
+
+struct uip_eth_addr uip_ethaddr = {{UIP_ETHADDR0,
+				    UIP_ETHADDR1,
+				    UIP_ETHADDR2,
+				    UIP_ETHADDR3,
+				    UIP_ETHADDR4,
+				    UIP_ETHADDR5}};
+
+static struct arp_entry arp_table[UIP_ARPTAB_SIZE];
+static u16_t ipaddr[2];
+static u8_t i, c;
+
+static u8_t arptime;
+static u8_t tmpage;
+
+#define BUF   ((struct arp_hdr *)&uip_buf[0])
+#define IPBUF ((struct ethip_hdr *)&uip_buf[0])
+/*-----------------------------------------------------------------------------------*/
+/**
+ * Initialize the ARP module.
+ *
+ */
+/*-----------------------------------------------------------------------------------*/
+void
+uip_arp_init(void)
+{
+  for(i = 0; i < UIP_ARPTAB_SIZE; ++i) {
+    memset(arp_table[i].ipaddr, 0, 4);
+  }
+}
+/*-----------------------------------------------------------------------------------*/
+/**
+ * Periodic ARP processing function.
+ *
+ * This function performs periodic timer processing in the ARP module
+ * and should be called at regular intervals. The recommended interval
+ * is 10 seconds between the calls.
+ *
+ */
+/*-----------------------------------------------------------------------------------*/
+void
+uip_arp_timer(void)
+{
+  struct arp_entry *tabptr;
+  
+  ++arptime;
+  for(i = 0; i < UIP_ARPTAB_SIZE; ++i) {
+    tabptr = &arp_table[i];
+    if((tabptr->ipaddr[0] | tabptr->ipaddr[1]) != 0 &&
+       arptime - tabptr->time >= UIP_ARP_MAXAGE) {
+      memset(tabptr->ipaddr, 0, 4);
+    }
+  }
+
+}
+/*-----------------------------------------------------------------------------------*/
+static void
+uip_arp_update(u16_t *ipaddr, struct uip_eth_addr *ethaddr)
+{
+  register struct arp_entry *tabptr;
+  /* Walk through the ARP mapping table and try to find an entry to
+     update. If none is found, the IP -> MAC address mapping is
+     inserted in the ARP table. */
+  for(i = 0; i < UIP_ARPTAB_SIZE; ++i) {
+
+    tabptr = &arp_table[i];
+    /* Only check those entries that are actually in use. */
+    if(tabptr->ipaddr[0] != 0 &&
+       tabptr->ipaddr[1] != 0) {
+
+      /* Check if the source IP address of the incoming packet matches
+         the IP address in this ARP table entry. */
+      if(ipaddr[0] == tabptr->ipaddr[0] &&
+	 ipaddr[1] == tabptr->ipaddr[1]) {
+	 
+	/* An old entry found, update this and return. */
+	memcpy(tabptr->ethaddr.addr, ethaddr->addr, 6);
+	tabptr->time = arptime;
+
+	return;
+      }
+    }
+  }
+
+  /* If we get here, no existing ARP table entry was found, so we
+     create one. */
+
+  /* First, we try to find an unused entry in the ARP table. */
+  for(i = 0; i < UIP_ARPTAB_SIZE; ++i) {
+    tabptr = &arp_table[i];
+    if(tabptr->ipaddr[0] == 0 &&
+       tabptr->ipaddr[1] == 0) {
+      break;
+    }
+  }
+
+  /* If no unused entry is found, we try to find the oldest entry and
+     throw it away. */
+  if(i == UIP_ARPTAB_SIZE) {
+    tmpage = 0;
+    c = 0;
+    for(i = 0; i < UIP_ARPTAB_SIZE; ++i) {
+      tabptr = &arp_table[i];
+      if(arptime - tabptr->time > tmpage) {
+	tmpage = arptime - tabptr->time;
+	c = i;
+      }
+    }
+    i = c;
+  }
+
+  /* Now, i is the ARP table entry which we will fill with the new
+     information. */
+  memcpy(tabptr->ipaddr, ipaddr, 4);
+  memcpy(tabptr->ethaddr.addr, ethaddr->addr, 6);
+  tabptr->time = arptime;
+}
+/*-----------------------------------------------------------------------------------*/
+/**
+ * ARP processing for incoming IP packets
+ *
+ * This function should be called by the device driver when an IP
+ * packet has been received. The function will check if the address is
+ * in the ARP cache, and if so the ARP cache entry will be
+ * refreshed. If no ARP cache entry was found, a new one is created.
+ *
+ * This function expects an IP packet with a prepended Ethernet header
+ * in the uip_buf[] buffer, and the length of the packet in the global
+ * variable uip_len.
+ */
+/*-----------------------------------------------------------------------------------*/
+void
+uip_arp_ipin(void)
+{
+  uip_len -= sizeof(struct uip_eth_hdr);
+	
+  /* Only insert/update an entry if the source IP address of the
+     incoming IP packet comes from a host on the local network. */
+  if((IPBUF->srcipaddr[0] & uip_arp_netmask[0]) !=
+     (uip_hostaddr[0] & uip_arp_netmask[0])) {
+    return;
+  }
+  if((IPBUF->srcipaddr[1] & uip_arp_netmask[1]) !=
+     (uip_hostaddr[1] & uip_arp_netmask[1])) {
+    return;
+  }
+  uip_arp_update(IPBUF->srcipaddr, &(IPBUF->ethhdr.src));
+  
+  return;
+}
+/*-----------------------------------------------------------------------------------*/
+/**
+ * ARP processing for incoming ARP packets.
+ *
+ * This function should be called by the device driver when an ARP
+ * packet has been received. The function will act differently
+ * depending on the ARP packet type: if it is a reply for a request
+ * that we previously sent out, the ARP cache will be filled in with
+ * the values from the ARP reply. If the incoming ARP packet is an ARP
+ * request for our IP address, an ARP reply packet is created and put
+ * into the uip_buf[] buffer.
+ *
+ * When the function returns, the value of the global variable uip_len
+ * indicates whether the device driver should send out a packet or
+ * not. If uip_len is zero, no packet should be sent. If uip_len is
+ * non-zero, it contains the length of the outbound packet that is
+ * present in the uip_buf[] buffer.
+ *
+ * This function expects an ARP packet with a prepended Ethernet
+ * header in the uip_buf[] buffer, and the length of the packet in the
+ * global variable uip_len.
+ */
+/*-----------------------------------------------------------------------------------*/
+void
+uip_arp_arpin(void)
+{
+
+  if(uip_len < sizeof(struct arp_hdr)) {
+    uip_len = 0;
+    return;
+  }
+
+  uip_len = 0;
+
+  switch(BUF->opcode) {
+  case HTONS(ARP_REQUEST):
+    /* ARP request. If it asked for our address, we send out a
+       reply. */
+    if(BUF->dipaddr[0] == uip_hostaddr[0] &&
+       BUF->dipaddr[1] == uip_hostaddr[1]) {
+      /* The reply opcode is 2. */
+      BUF->opcode = HTONS(2);
+
+      memcpy(BUF->dhwaddr.addr, BUF->shwaddr.addr, 6);
+      memcpy(BUF->shwaddr.addr, uip_ethaddr.addr, 6);
+      memcpy(BUF->ethhdr.src.addr, uip_ethaddr.addr, 6);
+      memcpy(BUF->ethhdr.dest.addr, BUF->dhwaddr.addr, 6);
+      
+      BUF->dipaddr[0] = BUF->sipaddr[0];
+      BUF->dipaddr[1] = BUF->sipaddr[1];
+      BUF->sipaddr[0] = uip_hostaddr[0];
+      BUF->sipaddr[1] = uip_hostaddr[1];
+
+      BUF->ethhdr.type = HTONS(UIP_ETHTYPE_ARP);      
+      uip_len = sizeof(struct arp_hdr);
+    }      
+    break;
+  case HTONS(ARP_REPLY):
+    /* ARP reply. We insert or update the ARP table if it was meant
+       for us. */
+    if(BUF->dipaddr[0] == uip_hostaddr[0] &&
+       BUF->dipaddr[1] == uip_hostaddr[1]) {
+
+      uip_arp_update(BUF->sipaddr, &BUF->shwaddr);
+    }
+    break;
+  }
+
+  return;
+}
+/*-----------------------------------------------------------------------------------*/
+/**
+ * Prepend Ethernet header to an outbound IP packet and see if we need
+ * to send out an ARP request.
+ *
+ * This function should be called before sending out an IP packet. The
+ * function checks the destination IP address of the IP packet to see
+ * what Ethernet MAC address that should be used as a destination MAC
+ * address on the Ethernet.
+ *
+ * If the destination IP address is in the local network (determined
+ * by logical ANDing of netmask and our IP address), the function
+ * checks the ARP cache to see if an entry for the destination IP
+ * address is found. If so, an Ethernet header is prepended and the
+ * function returns. If no ARP cache entry is found for the
+ * destination IP address, the packet in the uip_buf[] is replaced by
+ * an ARP request packet for the IP address. The IP packet is dropped
+ * and it is assumed that they higher level protocols (e.g., TCP)
+ * eventually will retransmit the dropped packet.
+ *
+ * If the destination IP address is not on the local network, the IP
+ * address of the default router is used instead.
+ *
+ * When the function returns, a packet is present in the uip_buf[]
+ * buffer, and the length of the packet is in the global variable
+ * uip_len.
+ */
+/*-----------------------------------------------------------------------------------*/
+void
+uip_arp_out(void)
+{
+  struct arp_entry *tabptr;
+  /* Find the destination IP address in the ARP table and construct
+     the Ethernet header. If the destination IP addres isn't on the
+     local network, we use the default router's IP address instead.
+
+     If not ARP table entry is found, we overwrite the original IP
+     packet with an ARP request for the IP address. */
+
+  /* Check if the destination address is on the local network. */
+  if((IPBUF->destipaddr[0] & uip_arp_netmask[0]) !=
+     (uip_hostaddr[0] & uip_arp_netmask[0]) ||
+     (IPBUF->destipaddr[1] & uip_arp_netmask[1]) !=
+     (uip_hostaddr[1] & uip_arp_netmask[1])) {
+    /* Destination address was not on the local network, so we need to
+       use the default router's IP address instead of the destination
+       address when determining the MAC address. */
+    ipaddr[0] = uip_arp_draddr[0];
+    ipaddr[1] = uip_arp_draddr[1];
+  } else {
+    /* Else, we use the destination IP address. */
+    ipaddr[0] = IPBUF->destipaddr[0];
+    ipaddr[1] = IPBUF->destipaddr[1];
+  }
+      
+  for(i = 0; i < UIP_ARPTAB_SIZE; ++i) {
+    tabptr = &arp_table[i];
+    if(ipaddr[0] == tabptr->ipaddr[0] &&
+       ipaddr[1] == tabptr->ipaddr[1])
+      break;
+  }
+
+  if(i == UIP_ARPTAB_SIZE) {
+    /* The destination address was not in our ARP table, so we
+       overwrite the IP packet with an ARP request. */
+
+    memset(BUF->ethhdr.dest.addr, 0xff, 6);
+    memset(BUF->dhwaddr.addr, 0x00, 6);
+    memcpy(BUF->ethhdr.src.addr, uip_ethaddr.addr, 6);
+    memcpy(BUF->shwaddr.addr, uip_ethaddr.addr, 6);
+    
+    BUF->dipaddr[0] = ipaddr[0];
+    BUF->dipaddr[1] = ipaddr[1];
+    BUF->sipaddr[0] = uip_hostaddr[0];
+    BUF->sipaddr[1] = uip_hostaddr[1];
+    BUF->opcode = HTONS(ARP_REQUEST); /* ARP request. */
+    BUF->hwtype = HTONS(ARP_HWTYPE_ETH);
+    BUF->protocol = HTONS(UIP_ETHTYPE_IP);
+    BUF->hwlen = 6;
+    BUF->protolen = 4;
+    BUF->ethhdr.type = HTONS(UIP_ETHTYPE_ARP);
+
+    uip_appdata = &uip_buf[40 + UIP_LLH_LEN];
+    
+    uip_len = sizeof(struct arp_hdr);
+    return;
+  }
+
+  /* Build an ethernet header. */
+  memcpy(IPBUF->ethhdr.dest.addr, tabptr->ethaddr.addr, 6);
+  memcpy(IPBUF->ethhdr.src.addr, uip_ethaddr.addr, 6);
+  
+  IPBUF->ethhdr.type = HTONS(UIP_ETHTYPE_IP);
+
+  uip_len += sizeof(struct uip_eth_hdr);
+}
+/*-----------------------------------------------------------------------------------*/
+
+/** @} */
+/** @} */

src/proto/uip/uip_arp.h

@@ -0,0 +1,201 @@
+/**
+ * \addtogroup uip
+ * @{
+ */
+
+/**
+ * \addtogroup uiparp 
+ * @{
+ */
+ 
+/**
+ * \file
+ * Macros and definitions for the ARP module.
+ * \author Adam Dunkels <adam@dunkels.com>
+ */
+  
+
+/*
+ * Copyright (c) 2001-2003, Adam Dunkels.
+ * All rights reserved. 
+ *
+ * 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. The name of the author may not be used to endorse or promote
+ *    products derived from this software without specific prior
+ *    written permission.  
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 AUTHOR 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.  
+ *
+ * This file is part of the uIP TCP/IP stack.
+ *
+ * $Id$
+ *
+ */
+
+#ifndef __UIP_ARP_H__
+#define __UIP_ARP_H__
+
+#include "uip.h"
+
+
+/**
+ * Representation of a 48-bit Ethernet address.
+ */
+struct uip_eth_addr {
+  u8_t addr[6];
+};
+
+extern struct uip_eth_addr uip_ethaddr;
+
+/**
+ * The Ethernet header. 
+ */
+struct uip_eth_hdr {
+  struct uip_eth_addr dest;
+  struct uip_eth_addr src;
+  u16_t type;
+};
+
+#define UIP_ETHTYPE_ARP 0x0806
+#define UIP_ETHTYPE_IP  0x0800
+#define UIP_ETHTYPE_IP6 0x86dd 
+
+
+/* The uip_arp_init() function must be called before any of the other
+   ARP functions. */
+void uip_arp_init(void);
+
+/* The uip_arp_ipin() function should be called whenever an IP packet
+   arrives from the Ethernet. This function refreshes the ARP table or
+   inserts a new mapping if none exists. The function assumes that an
+   IP packet with an Ethernet header is present in the uip_buf buffer
+   and that the length of the packet is in the uip_len variable. */
+void uip_arp_ipin(void);
+
+/* The uip_arp_arpin() should be called when an ARP packet is received
+   by the Ethernet driver. This function also assumes that the
+   Ethernet frame is present in the uip_buf buffer. When the
+   uip_arp_arpin() function returns, the contents of the uip_buf
+   buffer should be sent out on the Ethernet if the uip_len variable
+   is > 0. */
+void uip_arp_arpin(void);
+
+/* The uip_arp_out() function should be called when an IP packet
+   should be sent out on the Ethernet. This function creates an
+   Ethernet header before the IP header in the uip_buf buffer. The
+   Ethernet header will have the correct Ethernet MAC destination
+   address filled in if an ARP table entry for the destination IP
+   address (or the IP address of the default router) is present. If no
+   such table entry is found, the IP packet is overwritten with an ARP
+   request and we rely on TCP to retransmit the packet that was
+   overwritten. In any case, the uip_len variable holds the length of
+   the Ethernet frame that should be transmitted. */
+void uip_arp_out(void);
+
+/* The uip_arp_timer() function should be called every ten seconds. It
+   is responsible for flushing old entries in the ARP table. */
+void uip_arp_timer(void);
+
+/** @} */
+
+/**
+ * \addtogroup uipconffunc
+ * @{
+ */
+
+/**
+ * Set the default router's IP address.
+ *
+ * \param addr A pointer to a 4-byte array containing the IP address
+ * of the default router.
+ *
+ * \hideinitializer
+ */
+#define uip_setdraddr(addr) do { uip_arp_draddr[0] = addr[0]; \
+                                 uip_arp_draddr[1] = addr[1]; } while(0)
+
+/**
+ * Set the netmask.
+ *
+ * \param addr A pointer to a 4-byte array containing the IP address
+ * of the netmask.
+ *
+ * \hideinitializer
+ */
+#define uip_setnetmask(addr) do { uip_arp_netmask[0] = addr[0]; \
+                                  uip_arp_netmask[1] = addr[1]; } while(0)
+
+
+/**
+ * Get the default router's IP address.
+ *
+ * \param addr A pointer to a 4-byte array that will be filled in with
+ * the IP address of the default router.
+ *
+ * \hideinitializer
+ */
+#define uip_getdraddr(addr) do { addr[0] = uip_arp_draddr[0]; \
+                                 addr[1] = uip_arp_draddr[1]; } while(0)
+
+/**
+ * Get the netmask.
+ *
+ * \param addr A pointer to a 4-byte array that will be filled in with
+ * the value of the netmask.
+ *
+ * \hideinitializer
+ */
+#define uip_getnetmask(addr) do { addr[0] = uip_arp_netmask[0]; \
+                                  addr[1] = uip_arp_netmask[1]; } while(0)
+
+
+/**
+ * Specifiy the Ethernet MAC address.
+ *
+ * The ARP code needs to know the MAC address of the Ethernet card in
+ * order to be able to respond to ARP queries and to generate working
+ * Ethernet headers.
+ *
+ * \note This macro only specifies the Ethernet MAC address to the ARP
+ * code. It cannot be used to change the MAC address of the Ethernet
+ * card.
+ *
+ * \param eaddr A pointer to a struct uip_eth_addr containing the
+ * Ethernet MAC address of the Ethernet card.
+ *
+ * \hideinitializer
+ */
+#define uip_setethaddr(eaddr) do {uip_ethaddr.addr[0] = eaddr.addr[0]; \
+                              uip_ethaddr.addr[1] = eaddr.addr[1];\
+                              uip_ethaddr.addr[2] = eaddr.addr[2];\
+                              uip_ethaddr.addr[3] = eaddr.addr[3];\
+                              uip_ethaddr.addr[4] = eaddr.addr[4];\
+                              uip_ethaddr.addr[5] = eaddr.addr[5];} while(0)
+
+/** @} */
+
+/**
+ * \internal Internal variables that are set using the macros
+ * uip_setdraddr and uip_setnetmask.
+ */
+extern u16_t uip_arp_draddr[2], uip_arp_netmask[2];
+#endif /* __UIP_ARP_H__ */
+
+