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Diffstat (limited to 'lib/lufa/Projects/Webserver/Lib/uip/uip_arp.c')
| -rw-r--r-- | lib/lufa/Projects/Webserver/Lib/uip/uip_arp.c | 432 |
1 files changed, 432 insertions, 0 deletions
diff --git a/lib/lufa/Projects/Webserver/Lib/uip/uip_arp.c b/lib/lufa/Projects/Webserver/Lib/uip/uip_arp.c new file mode 100644 index 0000000000..fcb783b140 --- /dev/null +++ b/lib/lufa/Projects/Webserver/Lib/uip/uip_arp.c @@ -0,0 +1,432 @@ +/** + * \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: uip_arp.c,v 1.5 2008/02/07 01:35:00 adamdunkels Exp $ + * + */ + + +#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; + uip_ipaddr_t sipaddr; + struct uip_eth_addr dhwaddr; + uip_ipaddr_t dipaddr; +}; + +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; + uip_ipaddr_t srcipaddr, destipaddr; +}; + +#define ARP_REQUEST 1 +#define ARP_REPLY 2 + +#define ARP_HWTYPE_ETH 1 + +struct arp_entry { + uip_ipaddr_t ipaddr; + struct uip_eth_addr ethaddr; + u8_t time; +}; + +static const struct uip_eth_addr broadcast_ethaddr = + {{0xff,0xff,0xff,0xff,0xff,0xff}}; +static const u16_t broadcast_ipaddr[2] = {0xffff,0xffff}; + +static struct arp_entry arp_table[UIP_ARPTAB_SIZE]; +static uip_ipaddr_t ipaddr; +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]) + +#define DEBUG 0 +#if DEBUG +#include <stdio.h> +#define PRINTF(...) printf(__VA_ARGS__) +#else +#define PRINTF(...) +#endif + +/*-----------------------------------------------------------------------------------*/ +/** + * 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 = NULL; + + ++arptime; + for(i = 0; i < UIP_ARPTAB_SIZE; ++i) { + tabptr = &arp_table[i]; + if(uip_ipaddr_cmp(&tabptr->ipaddr, &uip_all_zeroes_addr) && + arptime - tabptr->time >= UIP_ARP_MAXAGE) { + memset(&tabptr->ipaddr, 0, 4); + } + } + +} +/*-----------------------------------------------------------------------------------*/ +static void +uip_arp_update(uip_ipaddr_t *ipaddr, struct uip_eth_addr *ethaddr) +{ + register struct arp_entry *tabptr = NULL; + /* 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(!uip_ipaddr_cmp(&tabptr->ipaddr, &uip_all_zeroes_addr)) { + + /* Check if the source IP address of the incoming packet matches + the IP address in this ARP table entry. */ + if(uip_ipaddr_cmp(ipaddr, &tabptr->ipaddr)) { + + /* 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(uip_ipaddr_cmp(&tabptr->ipaddr, &uip_all_zeroes_addr)) { + 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; + tabptr = &arp_table[i]; + } + + /* Now, i is the ARP table entry which we will fill with the new + information. */ + uip_ipaddr_copy(&tabptr->ipaddr, ipaddr); + 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. + */ +/*-----------------------------------------------------------------------------------*/ +#if 0 +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_netmask[0]) != + (uip_hostaddr[0] & uip_netmask[0])) { + return; + } + if((IPBUF->srcipaddr[1] & uip_netmask[1]) != + (uip_hostaddr[1] & uip_netmask[1])) { + return; + } + uip_arp_update(IPBUF->srcipaddr, &(IPBUF->ethhdr.src)); + + return; +} +#endif /* 0 */ +/*-----------------------------------------------------------------------------------*/ +/** + * 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]) {*/ + PRINTF("uip_arp_arpin: request for %d.%d.%d.%d (we are %d.%d.%d.%d)\n", + BUF->dipaddr.u8[0], BUF->dipaddr.u8[1], + BUF->dipaddr.u8[2], BUF->dipaddr.u8[3], + uip_hostaddr.u8[0], uip_hostaddr.u8[1], + uip_hostaddr.u8[2], uip_hostaddr.u8[3]); + if(uip_ipaddr_cmp(&BUF->dipaddr, &uip_hostaddr)) { + /* First, we register the one who made the request in our ARP + table, since it is likely that we will do more communication + with this host in the future. */ + uip_arp_update(&BUF->sipaddr, &BUF->shwaddr); + + BUF->opcode = HTONS(ARP_REPLY); + + 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); + + uip_ipaddr_copy(&BUF->dipaddr, &BUF->sipaddr); + uip_ipaddr_copy(&BUF->sipaddr, &uip_hostaddr); + + 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(uip_ipaddr_cmp(&BUF->dipaddr, &uip_hostaddr)) { + 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 = NULL; + + /* Find the destination IP address in the ARP table and construct + the Ethernet header. If the destination IP address 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. */ + + /* First check if destination is a local broadcast. */ + if(uip_ipaddr_cmp(&IPBUF->destipaddr, &uip_broadcast_addr)) { + memcpy(IPBUF->ethhdr.dest.addr, broadcast_ethaddr.addr, 6); + } else { + /* Check if the destination address is on the local network. */ + if(!uip_ipaddr_maskcmp(&IPBUF->destipaddr, &uip_hostaddr, &uip_netmask)) { + /* 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. */ + uip_ipaddr_copy(&ipaddr, &uip_draddr); + } else { + /* Else, we use the destination IP address. */ + uip_ipaddr_copy(&ipaddr, &IPBUF->destipaddr); + } + + for(i = 0; i < UIP_ARPTAB_SIZE; ++i) { + tabptr = &arp_table[i]; + if(uip_ipaddr_cmp(&ipaddr, &tabptr->ipaddr)) { + 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); + + uip_ipaddr_copy(&BUF->dipaddr, &ipaddr); + uip_ipaddr_copy(&BUF->sipaddr, &uip_hostaddr); + 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[UIP_TCPIP_HLEN + 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); +} +/*-----------------------------------------------------------------------------------*/ + +/** @} */ +/** @} */ + |