diff options
Diffstat (limited to 'core/lwip/src/netif/etharp.c')
| -rw-r--r-- | core/lwip/src/netif/etharp.c | 1318 |
1 files changed, 1318 insertions, 0 deletions
diff --git a/core/lwip/src/netif/etharp.c b/core/lwip/src/netif/etharp.c new file mode 100644 index 00000000..b60dadd0 --- /dev/null +++ b/core/lwip/src/netif/etharp.c @@ -0,0 +1,1318 @@ +/** + * @file + * Address Resolution Protocol module for IP over Ethernet + * + * Functionally, ARP is divided into two parts. The first maps an IP address + * to a physical address when sending a packet, and the second part answers + * requests from other machines for our physical address. + * + * This implementation complies with RFC 826 (Ethernet ARP). It supports + * Gratuitious ARP from RFC3220 (IP Mobility Support for IPv4) section 4.6 + * if an interface calls etharp_gratuitous(our_netif) upon address change. + */ + +/* + * Copyright (c) 2001-2003 Swedish Institute of Computer Science. + * Copyright (c) 2003-2004 Leon Woestenberg <leon.woestenberg@axon.tv> + * Copyright (c) 2003-2004 Axon Digital Design B.V., The Netherlands. + * 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 lwIP TCP/IP stack. + * + */ + +#include "lwip/opt.h" + +#if LWIP_ARP || LWIP_ETHERNET + +#include "lwip/ip_addr.h" +#include "lwip/def.h" +#include "lwip/ip.h" +#include "lwip/stats.h" +#include "lwip/snmp.h" +#include "lwip/dhcp.h" +#include "lwip/autoip.h" +#include "netif/etharp.h" + +#if PPPOE_SUPPORT +#include "netif/ppp_oe.h" +#endif /* PPPOE_SUPPORT */ + +#include <string.h> + +const struct eth_addr ethbroadcast = {{0xff,0xff,0xff,0xff,0xff,0xff}}; +const struct eth_addr ethzero = {{0,0,0,0,0,0}}; + +#if LWIP_ARP /* don't build if not configured for use in lwipopts.h */ + +/** the time an ARP entry stays valid after its last update, + * for ARP_TMR_INTERVAL = 5000, this is + * (240 * 5) seconds = 20 minutes. + */ +#define ARP_MAXAGE 240 +/** the time an ARP entry stays pending after first request, + * for ARP_TMR_INTERVAL = 5000, this is + * (2 * 5) seconds = 10 seconds. + * + * @internal Keep this number at least 2, otherwise it might + * run out instantly if the timeout occurs directly after a request. + */ +#define ARP_MAXPENDING 2 + +#define HWTYPE_ETHERNET 1 + +enum etharp_state { + ETHARP_STATE_EMPTY = 0, + ETHARP_STATE_PENDING, + ETHARP_STATE_STABLE +}; + +struct etharp_entry { +#if ARP_QUEUEING + /** Pointer to queue of pending outgoing packets on this ARP entry. */ + struct etharp_q_entry *q; +#else /* ARP_QUEUEING */ + /** Pointer to a single pending outgoing packet on this ARP entry. */ + struct pbuf *q; +#endif /* ARP_QUEUEING */ + ip_addr_t ipaddr; + struct eth_addr ethaddr; +#if LWIP_SNMP + struct netif *netif; +#endif /* LWIP_SNMP */ + u8_t state; + u8_t ctime; +#if ETHARP_SUPPORT_STATIC_ENTRIES + u8_t static_entry; +#endif /* ETHARP_SUPPORT_STATIC_ENTRIES */ +}; + +static struct etharp_entry arp_table[ARP_TABLE_SIZE]; + +#if !LWIP_NETIF_HWADDRHINT +static u8_t etharp_cached_entry; +#endif /* !LWIP_NETIF_HWADDRHINT */ + +/** Try hard to create a new entry - we want the IP address to appear in + the cache (even if this means removing an active entry or so). */ +#define ETHARP_FLAG_TRY_HARD 1 +#define ETHARP_FLAG_FIND_ONLY 2 +#define ETHARP_FLAG_STATIC_ENTRY 4 + +#if LWIP_NETIF_HWADDRHINT +#define ETHARP_SET_HINT(netif, hint) if (((netif) != NULL) && ((netif)->addr_hint != NULL)) \ + *((netif)->addr_hint) = (hint); +#else /* LWIP_NETIF_HWADDRHINT */ +#define ETHARP_SET_HINT(netif, hint) (etharp_cached_entry = (hint)) +#endif /* LWIP_NETIF_HWADDRHINT */ + +static err_t update_arp_entry(struct netif *netif, ip_addr_t *ipaddr, struct eth_addr *ethaddr, u8_t flags); + + +/* Some checks, instead of etharp_init(): */ +#if (LWIP_ARP && (ARP_TABLE_SIZE > 0x7f)) + #error "ARP_TABLE_SIZE must fit in an s8_t, you have to reduce it in your lwipopts.h" +#endif + + +#if ARP_QUEUEING +/** + * Free a complete queue of etharp entries + * + * @param q a qeueue of etharp_q_entry's to free + */ +static void +free_etharp_q(struct etharp_q_entry *q) +{ + struct etharp_q_entry *r; + LWIP_ASSERT("q != NULL", q != NULL); + LWIP_ASSERT("q->p != NULL", q->p != NULL); + while (q) { + r = q; + q = q->next; + LWIP_ASSERT("r->p != NULL", (r->p != NULL)); + pbuf_free(r->p); + memp_free(MEMP_ARP_QUEUE, r); + } +} +#else /* ARP_QUEUEING */ + +/** Compatibility define: free the queued pbuf */ +#define free_etharp_q(q) pbuf_free(q) + +#endif /* ARP_QUEUEING */ + +/** Clean up ARP table entries */ +static void +free_entry(int i) +{ + /* remove from SNMP ARP index tree */ + snmp_delete_arpidx_tree(arp_table[i].netif, &arp_table[i].ipaddr); + /* and empty packet queue */ + if (arp_table[i].q != NULL) { + /* remove all queued packets */ + LWIP_DEBUGF(ETHARP_DEBUG, ("etharp_timer: freeing entry %"U16_F", packet queue %p.\n", (u16_t)i, (void *)(arp_table[i].q))); + free_etharp_q(arp_table[i].q); + arp_table[i].q = NULL; + } + /* recycle entry for re-use */ + arp_table[i].state = ETHARP_STATE_EMPTY; +#if ETHARP_SUPPORT_STATIC_ENTRIES + arp_table[i].static_entry = 0; +#endif /* ETHARP_SUPPORT_STATIC_ENTRIES */ +#ifdef LWIP_DEBUG + /* for debugging, clean out the complete entry */ + arp_table[i].ctime = 0; +#if LWIP_SNMP + arp_table[i].netif = NULL; +#endif /* LWIP_SNMP */ + ip_addr_set_zero(&arp_table[i].ipaddr); + arp_table[i].ethaddr = ethzero; +#endif /* LWIP_DEBUG */ +} + +/** + * Clears expired entries in the ARP table. + * + * This function should be called every ETHARP_TMR_INTERVAL milliseconds (5 seconds), + * in order to expire entries in the ARP table. + */ +void +etharp_tmr(void) +{ + u8_t i; + + LWIP_DEBUGF(ETHARP_DEBUG, ("etharp_timer\n")); + /* remove expired entries from the ARP table */ + for (i = 0; i < ARP_TABLE_SIZE; ++i) { + u8_t state = arp_table[i].state; + if (state != ETHARP_STATE_EMPTY +#if ETHARP_SUPPORT_STATIC_ENTRIES + && (arp_table[i].static_entry == 0) +#endif /* ETHARP_SUPPORT_STATIC_ENTRIES */ + ) { + arp_table[i].ctime++; + if ((arp_table[i].ctime >= ARP_MAXAGE) || + ((arp_table[i].state == ETHARP_STATE_PENDING) && + (arp_table[i].ctime >= ARP_MAXPENDING))) { + /* pending or stable entry has become old! */ + LWIP_DEBUGF(ETHARP_DEBUG, ("etharp_timer: expired %s entry %"U16_F".\n", + arp_table[i].state == ETHARP_STATE_STABLE ? "stable" : "pending", (u16_t)i)); + /* clean up entries that have just been expired */ + free_entry(i); + } +#if ARP_QUEUEING + /* still pending entry? (not expired) */ + if (arp_table[i].state == ETHARP_STATE_PENDING) { + /* resend an ARP query here? */ + } +#endif /* ARP_QUEUEING */ + } + } +} + +/** + * Search the ARP table for a matching or new entry. + * + * If an IP address is given, return a pending or stable ARP entry that matches + * the address. If no match is found, create a new entry with this address set, + * but in state ETHARP_EMPTY. The caller must check and possibly change the + * state of the returned entry. + * + * If ipaddr is NULL, return a initialized new entry in state ETHARP_EMPTY. + * + * In all cases, attempt to create new entries from an empty entry. If no + * empty entries are available and ETHARP_FLAG_TRY_HARD flag is set, recycle + * old entries. Heuristic choose the least important entry for recycling. + * + * @param ipaddr IP address to find in ARP cache, or to add if not found. + * @param flags @see definition of ETHARP_FLAG_* + * @param netif netif related to this address (used for NETIF_HWADDRHINT) + * + * @return The ARP entry index that matched or is created, ERR_MEM if no + * entry is found or could be recycled. + */ +static s8_t +find_entry(ip_addr_t *ipaddr, u8_t flags) +{ + s8_t old_pending = ARP_TABLE_SIZE, old_stable = ARP_TABLE_SIZE; + s8_t empty = ARP_TABLE_SIZE; + u8_t i = 0, age_pending = 0, age_stable = 0; + /* oldest entry with packets on queue */ + s8_t old_queue = ARP_TABLE_SIZE; + /* its age */ + u8_t age_queue = 0; + + /** + * a) do a search through the cache, remember candidates + * b) select candidate entry + * c) create new entry + */ + + /* a) in a single search sweep, do all of this + * 1) remember the first empty entry (if any) + * 2) remember the oldest stable entry (if any) + * 3) remember the oldest pending entry without queued packets (if any) + * 4) remember the oldest pending entry with queued packets (if any) + * 5) search for a matching IP entry, either pending or stable + * until 5 matches, or all entries are searched for. + */ + + for (i = 0; i < ARP_TABLE_SIZE; ++i) { + u8_t state = arp_table[i].state; + /* no empty entry found yet and now we do find one? */ + if ((empty == ARP_TABLE_SIZE) && (state == ETHARP_STATE_EMPTY)) { + LWIP_DEBUGF(ETHARP_DEBUG, ("find_entry: found empty entry %"U16_F"\n", (u16_t)i)); + /* remember first empty entry */ + empty = i; + } else if (state != ETHARP_STATE_EMPTY) { + LWIP_ASSERT("state == ETHARP_STATE_PENDING || state == ETHARP_STATE_STABLE", + state == ETHARP_STATE_PENDING || state == ETHARP_STATE_STABLE); + /* if given, does IP address match IP address in ARP entry? */ + if (ipaddr && ip_addr_cmp(ipaddr, &arp_table[i].ipaddr)) { + LWIP_DEBUGF(ETHARP_DEBUG | LWIP_DBG_TRACE, ("find_entry: found matching entry %"U16_F"\n", (u16_t)i)); + /* found exact IP address match, simply bail out */ + return i; + } + /* pending entry? */ + if (state == ETHARP_STATE_PENDING) { + /* pending with queued packets? */ + if (arp_table[i].q != NULL) { + if (arp_table[i].ctime >= age_queue) { + old_queue = i; + age_queue = arp_table[i].ctime; + } + } else + /* pending without queued packets? */ + { + if (arp_table[i].ctime >= age_pending) { + old_pending = i; + age_pending = arp_table[i].ctime; + } + } + /* stable entry? */ + } else if (state == ETHARP_STATE_STABLE) { +#if ETHARP_SUPPORT_STATIC_ENTRIES + /* don't record old_stable for static entries since they never expire */ + if (arp_table[i].static_entry == 0) +#endif /* ETHARP_SUPPORT_STATIC_ENTRIES */ + { + /* remember entry with oldest stable entry in oldest, its age in maxtime */ + if (arp_table[i].ctime >= age_stable) { + old_stable = i; + age_stable = arp_table[i].ctime; + } + } + } + } + } + /* { we have no match } => try to create a new entry */ + + /* don't create new entry, only search? */ + if (((flags & ETHARP_FLAG_FIND_ONLY) != 0) || + /* or no empty entry found and not allowed to recycle? */ + ((empty == ARP_TABLE_SIZE) && ((flags & ETHARP_FLAG_TRY_HARD) == 0))) { + LWIP_DEBUGF(ETHARP_DEBUG | LWIP_DBG_TRACE, ("find_entry: no empty entry found and not allowed to recycle\n")); + return (s8_t)ERR_MEM; + } + + /* b) choose the least destructive entry to recycle: + * 1) empty entry + * 2) oldest stable entry + * 3) oldest pending entry without queued packets + * 4) oldest pending entry with queued packets + * + * { ETHARP_FLAG_TRY_HARD is set at this point } + */ + + /* 1) empty entry available? */ + if (empty < ARP_TABLE_SIZE) { + i = empty; + LWIP_DEBUGF(ETHARP_DEBUG | LWIP_DBG_TRACE, ("find_entry: selecting empty entry %"U16_F"\n", (u16_t)i)); + } else { + /* 2) found recyclable stable entry? */ + if (old_stable < ARP_TABLE_SIZE) { + /* recycle oldest stable*/ + i = old_stable; + LWIP_DEBUGF(ETHARP_DEBUG | LWIP_DBG_TRACE, ("find_entry: selecting oldest stable entry %"U16_F"\n", (u16_t)i)); + /* no queued packets should exist on stable entries */ + LWIP_ASSERT("arp_table[i].q == NULL", arp_table[i].q == NULL); + /* 3) found recyclable pending entry without queued packets? */ + } else if (old_pending < ARP_TABLE_SIZE) { + /* recycle oldest pending */ + i = old_pending; + LWIP_DEBUGF(ETHARP_DEBUG | LWIP_DBG_TRACE, ("find_entry: selecting oldest pending entry %"U16_F" (without queue)\n", (u16_t)i)); + /* 4) found recyclable pending entry with queued packets? */ + } else if (old_queue < ARP_TABLE_SIZE) { + /* recycle oldest pending (queued packets are free in free_entry) */ + i = old_queue; + LWIP_DEBUGF(ETHARP_DEBUG | LWIP_DBG_TRACE, ("find_entry: selecting oldest pending entry %"U16_F", freeing packet queue %p\n", (u16_t)i, (void *)(arp_table[i].q))); + /* no empty or recyclable entries found */ + } else { + LWIP_DEBUGF(ETHARP_DEBUG | LWIP_DBG_TRACE, ("find_entry: no empty or recyclable entries found\n")); + return (s8_t)ERR_MEM; + } + + /* { empty or recyclable entry found } */ + LWIP_ASSERT("i < ARP_TABLE_SIZE", i < ARP_TABLE_SIZE); + free_entry(i); + } + + LWIP_ASSERT("i < ARP_TABLE_SIZE", i < ARP_TABLE_SIZE); + LWIP_ASSERT("arp_table[i].state == ETHARP_STATE_EMPTY", + arp_table[i].state == ETHARP_STATE_EMPTY); + + /* IP address given? */ + if (ipaddr != NULL) { + /* set IP address */ + ip_addr_copy(arp_table[i].ipaddr, *ipaddr); + } + arp_table[i].ctime = 0; +#if ETHARP_SUPPORT_STATIC_ENTRIES + arp_table[i].static_entry = 0; +#endif /* ETHARP_SUPPORT_STATIC_ENTRIES */ + return (err_t)i; +} + +/** + * Send an IP packet on the network using netif->linkoutput + * The ethernet header is filled in before sending. + * + * @params netif the lwIP network interface on which to send the packet + * @params p the packet to send, p->payload pointing to the (uninitialized) ethernet header + * @params src the source MAC address to be copied into the ethernet header + * @params dst the destination MAC address to be copied into the ethernet header + * @return ERR_OK if the packet was sent, any other err_t on failure + */ +static err_t +etharp_send_ip(struct netif *netif, struct pbuf *p, struct eth_addr *src, struct eth_addr *dst) +{ + struct eth_hdr *ethhdr = (struct eth_hdr *)p->payload; + + LWIP_ASSERT("netif->hwaddr_len must be the same as ETHARP_HWADDR_LEN for etharp!", + (netif->hwaddr_len == ETHARP_HWADDR_LEN)); + ETHADDR32_COPY(ðhdr->dest, dst); + ETHADDR16_COPY(ðhdr->src, src); + ethhdr->type = PP_HTONS(ETHTYPE_IP); + LWIP_DEBUGF(ETHARP_DEBUG | LWIP_DBG_TRACE, ("etharp_send_ip: sending packet %p\n", (void *)p)); + /* send the packet */ + return netif->linkoutput(netif, p); +} + +/** + * Update (or insert) a IP/MAC address pair in the ARP cache. + * + * If a pending entry is resolved, any queued packets will be sent + * at this point. + * + * @param netif netif related to this entry (used for NETIF_ADDRHINT) + * @param ipaddr IP address of the inserted ARP entry. + * @param ethaddr Ethernet address of the inserted ARP entry. + * @param flags @see definition of ETHARP_FLAG_* + * + * @return + * - ERR_OK Succesfully updated ARP cache. + * - ERR_MEM If we could not add a new ARP entry when ETHARP_FLAG_TRY_HARD was set. + * - ERR_ARG Non-unicast address given, those will not appear in ARP cache. + * + * @see pbuf_free() + */ +static err_t +update_arp_entry(struct netif *netif, ip_addr_t *ipaddr, struct eth_addr *ethaddr, u8_t flags) +{ + s8_t i; + LWIP_ASSERT("netif->hwaddr_len == ETHARP_HWADDR_LEN", netif->hwaddr_len == ETHARP_HWADDR_LEN); + LWIP_DEBUGF(ETHARP_DEBUG | LWIP_DBG_TRACE, ("update_arp_entry: %"U16_F".%"U16_F".%"U16_F".%"U16_F" - %02"X16_F":%02"X16_F":%02"X16_F":%02"X16_F":%02"X16_F":%02"X16_F"\n", + ip4_addr1_16(ipaddr), ip4_addr2_16(ipaddr), ip4_addr3_16(ipaddr), ip4_addr4_16(ipaddr), + ethaddr->addr[0], ethaddr->addr[1], ethaddr->addr[2], + ethaddr->addr[3], ethaddr->addr[4], ethaddr->addr[5])); + /* non-unicast address? */ + if (ip_addr_isany(ipaddr) || + ip_addr_isbroadcast(ipaddr, netif) || + ip_addr_ismulticast(ipaddr)) { + LWIP_DEBUGF(ETHARP_DEBUG | LWIP_DBG_TRACE, ("update_arp_entry: will not add non-unicast IP address to ARP cache\n")); + return ERR_ARG; + } + /* find or create ARP entry */ + i = find_entry(ipaddr, flags); + /* bail out if no entry could be found */ + if (i < 0) { + return (err_t)i; + } + +#if ETHARP_SUPPORT_STATIC_ENTRIES + if (flags & ETHARP_FLAG_STATIC_ENTRY) { + /* record static type */ + arp_table[i].static_entry = 1; + } +#endif /* ETHARP_SUPPORT_STATIC_ENTRIES */ + + /* mark it stable */ + arp_table[i].state = ETHARP_STATE_STABLE; + +#if LWIP_SNMP + /* record network interface */ + arp_table[i].netif = netif; +#endif /* LWIP_SNMP */ + /* insert in SNMP ARP index tree */ + snmp_insert_arpidx_tree(netif, &arp_table[i].ipaddr); + + LWIP_DEBUGF(ETHARP_DEBUG | LWIP_DBG_TRACE, ("update_arp_entry: updating stable entry %"S16_F"\n", (s16_t)i)); + /* update address */ + ETHADDR32_COPY(&arp_table[i].ethaddr, ethaddr); + /* reset time stamp */ + arp_table[i].ctime = 0; + /* this is where we will send out queued packets! */ +#if ARP_QUEUEING + while (arp_table[i].q != NULL) { + struct pbuf *p; + /* remember remainder of queue */ + struct etharp_q_entry *q = arp_table[i].q; + /* pop first item off the queue */ + arp_table[i].q = q->next; + /* get the packet pointer */ + p = q->p; + /* now queue entry can be freed */ + memp_free(MEMP_ARP_QUEUE, q); +#else /* ARP_QUEUEING */ + if (arp_table[i].q != NULL) { + struct pbuf *p = arp_table[i].q; + arp_table[i].q = NULL; +#endif /* ARP_QUEUEING */ + /* send the queued IP packet */ + etharp_send_ip(netif, p, (struct eth_addr*)(netif->hwaddr), ethaddr); + /* free the queued IP packet */ + pbuf_free(p); + } + return ERR_OK; +} + +#if ETHARP_SUPPORT_STATIC_ENTRIES +/** Add a new static entry to the ARP table. If an entry exists for the + * specified IP address, this entry is overwritten. + * If packets are queued for the specified IP address, they are sent out. + * + * @param ipaddr IP address for the new static entry + * @param ethaddr ethernet address for the new static entry + * @return @see return values of etharp_add_static_entry + */ +err_t +etharp_add_static_entry(ip_addr_t *ipaddr, struct eth_addr *ethaddr) +{ + struct netif *netif; + LWIP_DEBUGF(ETHARP_DEBUG | LWIP_DBG_TRACE, ("etharp_add_static_entry: %"U16_F".%"U16_F".%"U16_F".%"U16_F" - %02"X16_F":%02"X16_F":%02"X16_F":%02"X16_F":%02"X16_F":%02"X16_F"\n", + ip4_addr1_16(ipaddr), ip4_addr2_16(ipaddr), ip4_addr3_16(ipaddr), ip4_addr4_16(ipaddr), + ethaddr->addr[0], ethaddr->addr[1], ethaddr->addr[2], + ethaddr->addr[3], ethaddr->addr[4], ethaddr->addr[5])); + + netif = ip_route(ipaddr); + if (netif == NULL) { + return ERR_RTE; + } + + return update_arp_entry(netif, ipaddr, ethaddr, ETHARP_FLAG_TRY_HARD | ETHARP_FLAG_STATIC_ENTRY); +} + +/** Remove a static entry from the ARP table previously added with a call to + * etharp_add_static_entry. + * + * @param ipaddr IP address of the static entry to remove + * @return ERR_OK: entry removed + * ERR_MEM: entry wasn't found + * ERR_ARG: entry wasn't a static entry but a dynamic one + */ +err_t +etharp_remove_static_entry(ip_addr_t *ipaddr) +{ + s8_t i; + LWIP_DEBUGF(ETHARP_DEBUG | LWIP_DBG_TRACE, ("etharp_remove_static_entry: %"U16_F".%"U16_F".%"U16_F".%"U16_F"\n", + ip4_addr1_16(ipaddr), ip4_addr2_16(ipaddr), ip4_addr3_16(ipaddr), ip4_addr4_16(ipaddr))); + + /* find or create ARP entry */ + i = find_entry(ipaddr, ETHARP_FLAG_FIND_ONLY); + /* bail out if no entry could be found */ + if (i < 0) { + return (err_t)i; + } + + if ((arp_table[i].state != ETHARP_STATE_STABLE) || + (arp_table[i].static_entry == 0)) { + /* entry wasn't a static entry, cannot remove it */ + return ERR_ARG; + } + /* entry found, free it */ + free_entry(i); + return ERR_OK; +} +#endif /* ETHARP_SUPPORT_STATIC_ENTRIES */ + +/** + * Finds (stable) ethernet/IP address pair from ARP table + * using interface and IP address index. + * @note the addresses in the ARP table are in network order! + * + * @param netif points to interface index + * @param ipaddr points to the (network order) IP address index + * @param eth_ret points to return pointer + * @param ip_ret points to return pointer + * @return table index if found, -1 otherwise + */ +s8_t +etharp_find_addr(struct netif *netif, ip_addr_t *ipaddr, + struct eth_addr **eth_ret, ip_addr_t **ip_ret) +{ + s8_t i; + + LWIP_ASSERT("eth_ret != NULL && ip_ret != NULL", + eth_ret != NULL && ip_ret != NULL); + + LWIP_UNUSED_ARG(netif); + + i = find_entry(ipaddr, ETHARP_FLAG_FIND_ONLY); + if((i >= 0) && arp_table[i].state == ETHARP_STATE_STABLE) { + *eth_ret = &arp_table[i].ethaddr; + *ip_ret = &arp_table[i].ipaddr; + return i; + } + return -1; +} + +#if ETHARP_TRUST_IP_MAC +/** + * Updates the ARP table using the given IP packet. + * + * Uses the incoming IP packet's source address to update the + * ARP cache for the local network. The function does not alter + * or free the packet. This function must be called before the + * packet p is passed to the IP layer. + * + * @param netif The lwIP network interface on which the IP packet pbuf arrived. + * @param p The IP packet that arrived on netif. + * + * @return NULL + * + * @see pbuf_free() + */ +static void +etharp_ip_input(struct netif *netif, struct pbuf *p) +{ + struct eth_hdr *ethhdr; + struct ip_hdr *iphdr; + ip_addr_t iphdr_src; + LWIP_ERROR("netif != NULL", (netif != NULL), return;); + + /* Only insert an entry if the source IP address of the + incoming IP packet comes from a host on the local network. */ + ethhdr = (struct eth_hdr *)p->payload; + iphdr = (struct ip_hdr *)((u8_t*)ethhdr + SIZEOF_ETH_HDR); +#if ETHARP_SUPPORT_VLAN + if (ethhdr->type == PP_HTONS(ETHTYPE_VLAN)) { + iphdr = (struct ip_hdr *)((u8_t*)ethhdr + SIZEOF_ETH_HDR + SIZEOF_VLAN_HDR); + } +#endif /* ETHARP_SUPPORT_VLAN */ + + ip_addr_copy(iphdr_src, iphdr->src); + + /* source is not on the local network? */ + if (!ip_addr_netcmp(&iphdr_src, &(netif->ip_addr), &(netif->netmask))) { + /* do nothing */ + return; + } + + LWIP_DEBUGF(ETHARP_DEBUG | LWIP_DBG_TRACE, ("etharp_ip_input: updating ETHARP table.\n")); + /* update the source IP address in the cache, if present */ + /* @todo We could use ETHARP_FLAG_TRY_HARD if we think we are going to talk + * back soon (for example, if the destination IP address is ours. */ + update_arp_entry(netif, &iphdr_src, &(ethhdr->src), ETHARP_FLAG_FIND_ONLY); +} +#endif /* ETHARP_TRUST_IP_MAC */ + +/** + * Responds to ARP requests to us. Upon ARP replies to us, add entry to cache + * send out queued IP packets. Updates cache with snooped address pairs. + * + * Should be called for incoming ARP packets. The pbuf in the argument + * is freed by this function. + * + * @param netif The lwIP network interface on which the ARP packet pbuf arrived. + * @param ethaddr Ethernet address of netif. + * @param p The ARP packet that arrived on netif. Is freed by this function. + * + * @return NULL + * + * @see pbuf_free() + */ +static void +etharp_arp_input(struct netif *netif, struct eth_addr *ethaddr, struct pbuf *p) +{ + struct etharp_hdr *hdr; + struct eth_hdr *ethhdr; + /* these are aligned properly, whereas the ARP header fields might not be */ + ip_addr_t sipaddr, dipaddr; + u8_t for_us; +#if LWIP_AUTOIP + const u8_t * ethdst_hwaddr; +#endif /* LWIP_AUTOIP */ + + LWIP_ERROR("netif != NULL", (netif != NULL), return;); + + /* drop short ARP packets: we have to check for p->len instead of p->tot_len here + since a struct etharp_hdr is pointed to p->payload, so it musn't be chained! */ + if (p->len < SIZEOF_ETHARP_PACKET) { + LWIP_DEBUGF(ETHARP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_LEVEL_WARNING, + ("etharp_arp_input: packet dropped, too short (%"S16_F"/%"S16_F")\n", p->tot_len, + (s16_t)SIZEOF_ETHARP_PACKET)); + ETHARP_STATS_INC(etharp.lenerr); + ETHARP_STATS_INC(etharp.drop); + pbuf_free(p); + return; + } + + ethhdr = (struct eth_hdr *)p->payload; + hdr = (struct etharp_hdr *)((u8_t*)ethhdr + SIZEOF_ETH_HDR); +#if ETHARP_SUPPORT_VLAN + if (ethhdr->type == PP_HTONS(ETHTYPE_VLAN)) { + hdr = (struct etharp_hdr *)(((u8_t*)ethhdr) + SIZEOF_ETH_HDR + SIZEOF_VLAN_HDR); + } +#endif /* ETHARP_SUPPORT_VLAN */ + + /* RFC 826 "Packet Reception": */ + if ((hdr->hwtype != PP_HTONS(HWTYPE_ETHERNET)) || + (hdr->hwlen != ETHARP_HWADDR_LEN) || + (hdr->protolen != sizeof(ip_addr_t)) || + (hdr->proto != PP_HTONS(ETHTYPE_IP))) { + LWIP_DEBUGF(ETHARP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_LEVEL_WARNING, + ("etharp_arp_input: packet dropped, wrong hw type, hwlen, proto, protolen or ethernet type (%"U16_F"/%"U16_F"/%"U16_F"/%"U16_F")\n", + hdr->hwtype, hdr->hwlen, hdr->proto, hdr->protolen)); + ETHARP_STATS_INC(etharp.proterr); + ETHARP_STATS_INC(etharp.drop); + pbuf_free(p); + return; + } + ETHARP_STATS_INC(etharp.recv); + +#if LWIP_AUTOIP + /* We have to check if a host already has configured our random + * created link local address and continously check if there is + * a host with this IP-address so we can detect collisions */ + autoip_arp_reply(netif, hdr); +#endif /* LWIP_AUTOIP */ + + /* Copy struct ip_addr2 to aligned ip_addr, to support compilers without + * structure packing (not using structure copy which breaks strict-aliasing rules). */ + IPADDR2_COPY(&sipaddr, &hdr->sipaddr); + IPADDR2_COPY(&dipaddr, &hdr->dipaddr); + + /* this interface is not configured? */ + if (ip_addr_isany(&netif->ip_addr)) { + for_us = 0; + } else { + /* ARP packet directed to us? */ + for_us = (u8_t)ip_addr_cmp(&dipaddr, &(netif->ip_addr)); + } + + /* ARP message directed to us? + -> add IP address in ARP cache; assume requester wants to talk to us, + can result in directly sending the queued packets for this host. + ARP message not directed to us? + -> update the source IP address in the cache, if present */ + update_arp_entry(netif, &sipaddr, &(hdr->shwaddr), + for_us ? ETHARP_FLAG_TRY_HARD : ETHARP_FLAG_FIND_ONLY); + + /* now act on the message itself */ + switch (hdr->opcode) { + /* ARP request? */ + case PP_HTONS(ARP_REQUEST): + /* ARP request. If it asked for our address, we send out a + * reply. In any case, we time-stamp any existing ARP entry, + * and possiby send out an IP packet that was queued on it. */ + + LWIP_DEBUGF (ETHARP_DEBUG | LWIP_DBG_TRACE, ("etharp_arp_input: incoming ARP request\n")); + /* ARP request for our address? */ + if (for_us) { + + LWIP_DEBUGF(ETHARP_DEBUG | LWIP_DBG_TRACE, ("etharp_arp_input: replying to ARP request for our IP address\n")); + /* Re-use pbuf to send ARP reply. + Since we are re-using an existing pbuf, we can't call etharp_raw since + that would allocate a new pbuf. */ + hdr->opcode = htons(ARP_REPLY); + + IPADDR2_COPY(&hdr->dipaddr, &hdr->sipaddr); + IPADDR2_COPY(&hdr->sipaddr, &netif->ip_addr); + + LWIP_ASSERT("netif->hwaddr_len must be the same as ETHARP_HWADDR_LEN for etharp!", + (netif->hwaddr_len == ETHARP_HWADDR_LEN)); +#if LWIP_AUTOIP + /* If we are using Link-Local, all ARP packets that contain a Link-Local + * 'sender IP address' MUST be sent using link-layer broadcast instead of + * link-layer unicast. (See RFC3927 Section 2.5, last paragraph) */ + ethdst_hwaddr = ip_addr_islinklocal(&netif->ip_addr) ? (u8_t*)(ethbroadcast.addr) : hdr->shwaddr.addr; +#endif /* LWIP_AUTOIP */ + + ETHADDR16_COPY(&hdr->dhwaddr, &hdr->shwaddr); +#if LWIP_AUTOIP + ETHADDR16_COPY(ðhdr->dest, ethdst_hwaddr); +#else /* LWIP_AUTOIP */ + ETHADDR16_COPY(ðhdr->dest, &hdr->shwaddr); +#endif /* LWIP_AUTOIP */ + ETHADDR16_COPY(&hdr->shwaddr, ethaddr); + ETHADDR16_COPY(ðhdr->src, ethaddr); + + /* hwtype, hwaddr_len, proto, protolen and the type in the ethernet header + are already correct, we tested that before */ + + /* return ARP reply */ + netif->linkoutput(netif, p); + /* we are not configured? */ + } else if (ip_addr_isany(&netif->ip_addr)) { + /* { for_us == 0 and netif->ip_addr.addr == 0 } */ + LWIP_DEBUGF(ETHARP_DEBUG | LWIP_DBG_TRACE, ("etharp_arp_input: we are unconfigured, ARP request ignored.\n")); + /* request was not directed to us */ + } else { + /* { for_us == 0 and netif->ip_addr.addr != 0 } */ + LWIP_DEBUGF(ETHARP_DEBUG | LWIP_DBG_TRACE, ("etharp_arp_input: ARP request was not for us.\n")); + } + break; + case PP_HTONS(ARP_REPLY): + /* ARP reply. We already updated the ARP cache earlier. */ + LWIP_DEBUGF(ETHARP_DEBUG | LWIP_DBG_TRACE, ("etharp_arp_input: incoming ARP reply\n")); +#if (LWIP_DHCP && DHCP_DOES_ARP_CHECK) + /* DHCP wants to know about ARP replies from any host with an + * IP address also offered to us by the DHCP server. We do not + * want to take a duplicate IP address on a single network. + * @todo How should we handle redundant (fail-over) interfaces? */ + dhcp_arp_reply(netif, &sipaddr); +#endif /* (LWIP_DHCP && DHCP_DOES_ARP_CHECK) */ + break; + default: + LWIP_DEBUGF(ETHARP_DEBUG | LWIP_DBG_TRACE, ("etharp_arp_input: ARP unknown opcode type %"S16_F"\n", htons(hdr->opcode))); + ETHARP_STATS_INC(etharp.err); + break; + } + /* free ARP packet */ + pbuf_free(p); +} + +/** + * Resolve and fill-in Ethernet address header for outgoing IP packet. + * + * For IP multicast and broadcast, corresponding Ethernet addresses + * are selected and the packet is transmitted on the link. + * + * For unicast addresses, the packet is submitted to etharp_query(). In + * case the IP address is outside the local network, the IP address of + * the gateway is used. + * + * @param netif The lwIP network interface which the IP packet will be sent on. + * @param q The pbuf(s) containing the IP packet to be sent. + * @param ipaddr The IP address of the packet destination. + * + * @return + * - ERR_RTE No route to destination (no gateway to external networks), + * or the return type of either etharp_query() or etharp_send_ip(). + */ +err_t +etharp_output(struct netif *netif, struct pbuf *q, ip_addr_t *ipaddr) +{ + struct eth_addr *dest, mcastaddr; + + /* make room for Ethernet header - should not fail */ + if (pbuf_header(q, sizeof(struct eth_hdr)) != 0) { + /* bail out */ + LWIP_DEBUGF(ETHARP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_LEVEL_SERIOUS, + ("etharp_output: could not allocate room for header.\n")); + LINK_STATS_INC(link.lenerr); + return ERR_BUF; + } + + /* assume unresolved Ethernet address */ + dest = NULL; + /* Determine on destination hardware address. Broadcasts and multicasts + * are special, other IP addresses are looked up in the ARP table. */ + + /* broadcast destination IP address? */ + if (ip_addr_isbroadcast(ipaddr, netif)) { + /* broadcast on Ethernet also */ + dest = (struct eth_addr *)ðbroadcast; + /* multicast destination IP address? */ + } else if (ip_addr_ismulticast(ipaddr)) { + /* Hash IP multicast address to MAC address.*/ + mcastaddr.addr[0] = 0x01; + mcastaddr.addr[1] = 0x00; + mcastaddr.addr[2] = 0x5e; + mcastaddr.addr[3] = ip4_addr2(ipaddr) & 0x7f; + mcastaddr.addr[4] = ip4_addr3(ipaddr); + mcastaddr.addr[5] = ip4_addr4(ipaddr); + /* destination Ethernet address is multicast */ + dest = &mcastaddr; + /* unicast destination IP address? */ + } else { + /* outside local network? */ + if (!ip_addr_netcmp(ipaddr, &(netif->ip_addr), &(netif->netmask)) && + !ip_addr_islinklocal(ipaddr)) { +#if LWIP_AUTOIP + struct ip_hdr *iphdr = (struct ip_hdr*)((u8_t*)q->payload + + sizeof(struct eth_hdr)); + /* According to RFC 3297, chapter 2.6.2 (Forwarding Rules), a packet with + a link-local source address must always be "directly to its destination + on the same physical link. The host MUST NOT send the packet to any + router for forwarding". */ + if (!ip_addr_islinklocal(&iphdr->src)) +#endif /* LWIP_AUTOIP */ + { + /* interface has default gateway? */ + if (!ip_addr_isany(&netif->gw)) { + /* send to hardware address of default gateway IP address */ + ipaddr = &(netif->gw); + /* no default gateway available */ + } else { + /* no route to destination error (default gateway missing) */ + return ERR_RTE; + } + } + } +#if LWIP_NETIF_HWADDRHINT + if (netif->addr_hint != NULL) { + /* per-pcb cached entry was given */ + u8_t etharp_cached_entry = *(netif->addr_hint); + if (etharp_cached_entry < ARP_TABLE_SIZE) { +#endif /* LWIP_NETIF_HWADDRHINT */ + if ((arp_table[etharp_cached_entry].state == ETHARP_STATE_STABLE) && + (ip_addr_cmp(ipaddr, &arp_table[etharp_cached_entry].ipaddr))) { + /* the per-pcb-cached entry is stable and the right one! */ + ETHARP_STATS_INC(etharp.cachehit); + return etharp_send_ip(netif, q, (struct eth_addr*)(netif->hwaddr), + &arp_table[etharp_cached_entry].ethaddr); + } +#if LWIP_NETIF_HWADDRHINT + } + } +#endif /* LWIP_NETIF_HWADDRHINT */ + /* queue on destination Ethernet address belonging to ipaddr */ + return etharp_query(netif, ipaddr, q); + } + + /* continuation for multicast/broadcast destinations */ + /* obtain source Ethernet address of the given interface */ + /* send packet directly on the link */ + return etharp_send_ip(netif, q, (struct eth_addr*)(netif->hwaddr), dest); +} + +/** + * Send an ARP request for the given IP address and/or queue a packet. + * + * If the IP address was not yet in the cache, a pending ARP cache entry + * is added and an ARP request is sent for the given address. The packet + * is queued on this entry. + * + * If the IP address was already pending in the cache, a new ARP request + * is sent for the given address. The packet is queued on this entry. + * + * If the IP address was already stable in the cache, and a packet is + * given, it is directly sent and no ARP request is sent out. + * + * If the IP address was already stable in the cache, and no packet is + * given, an ARP request is sent out. + * + * @param netif The lwIP network interface on which ipaddr + * must be queried for. + * @param ipaddr The IP address to be resolved. + * @param q If non-NULL, a pbuf that must be delivered to the IP address. + * q is not freed by this function. + * + * @note q must only be ONE packet, not a packet queue! + * + * @return + * - ERR_BUF Could not make room for Ethernet header. + * - ERR_MEM Hardware address unknown, and no more ARP entries available + * to query for address or queue the packet. + * - ERR_MEM Could not queue packet due to memory shortage. + * - ERR_RTE No route to destination (no gateway to external networks). + * - ERR_ARG Non-unicast address given, those will not appear in ARP cache. + * + */ +err_t +etharp_query(struct netif *netif, ip_addr_t *ipaddr, struct pbuf *q) +{ + struct eth_addr * srcaddr = (struct eth_addr *)netif->hwaddr; + err_t result = ERR_MEM; + s8_t i; /* ARP entry index */ + + /* non-unicast address? */ + if (ip_addr_isbroadcast(ipaddr, netif) || + ip_addr_ismulticast(ipaddr) || + ip_addr_isany(ipaddr)) { + LWIP_DEBUGF(ETHARP_DEBUG | LWIP_DBG_TRACE, ("etharp_query: will not add non-unicast IP address to ARP cache\n")); + return ERR_ARG; + } + + /* find entry in ARP cache, ask to create entry if queueing packet */ + i = find_entry(ipaddr, ETHARP_FLAG_TRY_HARD); + + /* could not find or create entry? */ + if (i < 0) { + LWIP_DEBUGF(ETHARP_DEBUG | LWIP_DBG_TRACE, ("etharp_query: could not create ARP entry\n")); + if (q) { + LWIP_DEBUGF(ETHARP_DEBUG | LWIP_DBG_TRACE, ("etharp_query: packet dropped\n")); + ETHARP_STATS_INC(etharp.memerr); + } + return (err_t)i; + } + + /* mark a fresh entry as pending (we just sent a request) */ + if (arp_table[i].state == ETHARP_STATE_EMPTY) { + arp_table[i].state = ETHARP_STATE_PENDING; + } + + /* { i is either a STABLE or (new or existing) PENDING entry } */ + LWIP_ASSERT("arp_table[i].state == PENDING or STABLE", + ((arp_table[i].state == ETHARP_STATE_PENDING) || + (arp_table[i].state == ETHARP_STATE_STABLE))); + + /* do we have a pending entry? or an implicit query request? */ + if ((arp_table[i].state == ETHARP_STATE_PENDING) || (q == NULL)) { + /* try to resolve it; send out ARP request */ + result = etharp_request(netif, ipaddr); + if (result != ERR_OK) { + /* ARP request couldn't be sent */ + /* We don't re-send arp request in etharp_tmr, but we still queue packets, + since this failure could be temporary, and the next packet calling + etharp_query again could lead to sending the queued packets. */ + } + if (q == NULL) { + return result; + } + } + + /* packet given? */ + LWIP_ASSERT("q != NULL", q != NULL); + /* stable entry? */ + if (arp_table[i].state == ETHARP_STATE_STABLE) { + /* we have a valid IP->Ethernet address mapping */ + ETHARP_SET_HINT(netif, i); + /* send the packet */ + result = etharp_send_ip(netif, q, srcaddr, &(arp_table[i].ethaddr)); + /* pending entry? (either just created or already pending */ + } else if (arp_table[i].state == ETHARP_STATE_PENDING) { + /* entry is still pending, queue the given packet 'q' */ + struct pbuf *p; + int copy_needed = 0; + /* IF q includes a PBUF_REF, PBUF_POOL or PBUF_RAM, we have no choice but + * to copy the whole queue into a new PBUF_RAM (see bug #11400) + * PBUF_ROMs can be left as they are, since ROM must not get changed. */ + p = q; + while (p) { + LWIP_ASSERT("no packet queues allowed!", (p->len != p->tot_len) || (p->next == 0)); + if(p->type != PBUF_ROM) { + copy_needed = 1; + break; + } + p = p->next; + } + if(copy_needed) { + /* copy the whole packet into new pbufs */ + p = pbuf_alloc(PBUF_RAW, p->tot_len, PBUF_RAM); + if(p != NULL) { + if (pbuf_copy(p, q) != ERR_OK) { + pbuf_free(p); + p = NULL; + } + } + } else { + /* referencing the old pbuf is enough */ + p = q; + pbuf_ref(p); + } + /* packet could be taken over? */ + if (p != NULL) { + /* queue packet ... */ +#if ARP_QUEUEING + struct etharp_q_entry *new_entry; + /* allocate a new arp queue entry */ + new_entry = (struct etharp_q_entry *)memp_malloc(MEMP_ARP_QUEUE); + if (new_entry != NULL) { + new_entry->next = 0; + new_entry->p = p; + if(arp_table[i].q != NULL) { + /* queue was already existent, append the new entry to the end */ + struct etharp_q_entry *r; + r = arp_table[i].q; + while (r->next != NULL) { + r = r->next; + } + r->next = new_entry; + } else { + /* queue did not exist, first item in queue */ + arp_table[i].q = new_entry; + } + LWIP_DEBUGF(ETHARP_DEBUG | LWIP_DBG_TRACE, ("etharp_query: queued packet %p on ARP entry %"S16_F"\n", (void *)q, (s16_t)i)); + result = ERR_OK; + } else { + /* the pool MEMP_ARP_QUEUE is empty */ + pbuf_free(p); + LWIP_DEBUGF(ETHARP_DEBUG | LWIP_DBG_TRACE, ("etharp_query: could not queue a copy of PBUF_REF packet %p (out of memory)\n", (void *)q)); + result = ERR_MEM; + } +#else /* ARP_QUEUEING */ + /* always queue one packet per ARP request only, freeing a previously queued packet */ + if (arp_table[i].q != NULL) { + LWIP_DEBUGF(ETHARP_DEBUG | LWIP_DBG_TRACE, ("etharp_query: dropped previously queued packet %p for ARP entry %"S16_F"\n", (void *)q, (s16_t)i)); + pbuf_free(arp_table[i].q); + } + arp_table[i].q = p; + result = ERR_OK; + LWIP_DEBUGF(ETHARP_DEBUG | LWIP_DBG_TRACE, ("etharp_query: queued packet %p on ARP entry %"S16_F"\n", (void *)q, (s16_t)i)); +#endif /* ARP_QUEUEING */ + } else { + ETHARP_STATS_INC(etharp.memerr); + LWIP_DEBUGF(ETHARP_DEBUG | LWIP_DBG_TRACE, ("etharp_query: could not queue a copy of PBUF_REF packet %p (out of memory)\n", (void *)q)); + result = ERR_MEM; + } + } + return result; +} + +/** + * Send a raw ARP packet (opcode and all addresses can be modified) + * + * @param netif the lwip network interface on which to send the ARP packet + * @param ethsrc_addr the source MAC address for the ethernet header + * @param ethdst_addr the destination MAC address for the ethernet header + * @param hwsrc_addr the source MAC address for the ARP protocol header + * @param ipsrc_addr the source IP address for the ARP protocol header + * @param hwdst_addr the destination MAC address for the ARP protocol header + * @param ipdst_addr the destination IP address for the ARP protocol header + * @param opcode the type of the ARP packet + * @return ERR_OK if the ARP packet has been sent + * ERR_MEM if the ARP packet couldn't be allocated + * any other err_t on failure + */ +#if !LWIP_AUTOIP +static +#endif /* LWIP_AUTOIP */ +err_t +etharp_raw(struct netif *netif, const struct eth_addr *ethsrc_addr, + const struct eth_addr *ethdst_addr, + const struct eth_addr *hwsrc_addr, const ip_addr_t *ipsrc_addr, + const struct eth_addr *hwdst_addr, const ip_addr_t *ipdst_addr, + const u16_t opcode) +{ + struct pbuf *p; + err_t result = ERR_OK; + struct eth_hdr *ethhdr; + struct etharp_hdr *hdr; +#if LWIP_AUTOIP + const u8_t * ethdst_hwaddr; +#endif /* LWIP_AUTOIP */ + + /* allocate a pbuf for the outgoing ARP request packet */ + p = pbuf_alloc(PBUF_RAW, SIZEOF_ETHARP_PACKET, PBUF_RAM); + /* could allocate a pbuf for an ARP request? */ + if (p == NULL) { + LWIP_DEBUGF(ETHARP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_LEVEL_SERIOUS, + ("etharp_raw: could not allocate pbuf for ARP request.\n")); + ETHARP_STATS_INC(etharp.memerr); + return ERR_MEM; + } + LWIP_ASSERT("check that first pbuf can hold struct etharp_hdr", + (p->len >= SIZEOF_ETHARP_PACKET)); + + ethhdr = (struct eth_hdr *)p->payload; + hdr = (struct etharp_hdr *)((u8_t*)ethhdr + SIZEOF_ETH_HDR); + LWIP_DEBUGF(ETHARP_DEBUG | LWIP_DBG_TRACE, ("etharp_raw: sending raw ARP packet.\n")); + hdr->opcode = htons(opcode); + + LWIP_ASSERT("netif->hwaddr_len must be the same as ETHARP_HWADDR_LEN for etharp!", + (netif->hwaddr_len == ETHARP_HWADDR_LEN)); +#if LWIP_AUTOIP + /* If we are using Link-Local, all ARP packets that contain a Link-Local + * 'sender IP address' MUST be sent using link-layer broadcast instead of + * link-layer unicast. (See RFC3927 Section 2.5, last paragraph) */ + ethdst_hwaddr = ip_addr_islinklocal(ipsrc_addr) ? (u8_t*)(ethbroadcast.addr) : ethdst_addr->addr; +#endif /* LWIP_AUTOIP */ + /* Write the ARP MAC-Addresses */ + ETHADDR16_COPY(&hdr->shwaddr, hwsrc_addr); + ETHADDR16_COPY(&hdr->dhwaddr, hwdst_addr); + /* Write the Ethernet MAC-Addresses */ +#if LWIP_AUTOIP + ETHADDR16_COPY(ðhdr->dest, ethdst_hwaddr); +#else /* LWIP_AUTOIP */ + ETHADDR16_COPY(ðhdr->dest, ethdst_addr); +#endif /* LWIP_AUTOIP */ + ETHADDR16_COPY(ðhdr->src, ethsrc_addr); + /* Copy struct ip_addr2 to aligned ip_addr, to support compilers without + * structure packing. */ + IPADDR2_COPY(&hdr->sipaddr, ipsrc_addr); + IPADDR2_COPY(&hdr->dipaddr, ipdst_addr); + + hdr->hwtype = PP_HTONS(HWTYPE_ETHERNET); + hdr->proto = PP_HTONS(ETHTYPE_IP); + /* set hwlen and protolen */ + hdr->hwlen = ETHARP_HWADDR_LEN; + hdr->protolen = sizeof(ip_addr_t); + + ethhdr->type = PP_HTONS(ETHTYPE_ARP); + /* send ARP query */ + result = netif->linkoutput(netif, p); + ETHARP_STATS_INC(etharp.xmit); + /* free ARP query packet */ + pbuf_free(p); + p = NULL; + /* could not allocate pbuf for ARP request */ + + return result; +} + +/** + * Send an ARP request packet asking for ipaddr. + * + * @param netif the lwip network interface on which to send the request + * @param ipaddr the IP address for which to ask + * @return ERR_OK if the request has been sent + * ERR_MEM if the ARP packet couldn't be allocated + * any other err_t on failure + */ +err_t +etharp_request(struct netif *netif, ip_addr_t *ipaddr) +{ + LWIP_DEBUGF(ETHARP_DEBUG | LWIP_DBG_TRACE, ("etharp_request: sending ARP request.\n")); + return etharp_raw(netif, (struct eth_addr *)netif->hwaddr, ðbroadcast, + (struct eth_addr *)netif->hwaddr, &netif->ip_addr, ðzero, + ipaddr, ARP_REQUEST); +} +#endif /* LWIP_ARP */ + +/** + * Process received ethernet frames. Using this function instead of directly + * calling ip_input and passing ARP frames through etharp in ethernetif_input, + * the ARP cache is protected from concurrent access. + * + * @param p the recevied packet, p->payload pointing to the ethernet header + * @param netif the network interface on which the packet was received + */ +err_t +ethernet_input(struct pbuf *p, struct netif *netif) +{ + struct eth_hdr* ethhdr; + u16_t type; + s16_t ip_hdr_offset = SIZEOF_ETH_HDR; + + if (p->len <= SIZEOF_ETH_HDR) { + /* a packet with only an ethernet header (or less) is not valid for us */ + ETHARP_STATS_INC(etharp.proterr); + ETHARP_STATS_INC(etharp.drop); + goto free_and_return; + } + + /* points to packet payload, which starts with an Ethernet header */ + ethhdr = (struct eth_hdr *)p->payload; + LWIP_DEBUGF(ETHARP_DEBUG | LWIP_DBG_TRACE, + ("ethernet_input: dest:%"X8_F":%"X8_F":%"X8_F":%"X8_F":%"X8_F":%"X8_F", src:%"X8_F":%"X8_F":%"X8_F":%"X8_F":%"X8_F":%"X8_F", type:%"X16_F"\n", + (unsigned)ethhdr->dest.addr[0], (unsigned)ethhdr->dest.addr[1], (unsigned)ethhdr->dest.addr[2], + (unsigned)ethhdr->dest.addr[3], (unsigned)ethhdr->dest.addr[4], (unsigned)ethhdr->dest.addr[5], + (unsigned)ethhdr->src.addr[0], (unsigned)ethhdr->src.addr[1], (unsigned)ethhdr->src.addr[2], + (unsigned)ethhdr->src.addr[3], (unsigned)ethhdr->src.addr[4], (unsigned)ethhdr->src.addr[5], + (unsigned)htons(ethhdr->type))); + + type = ethhdr->type; +#if ETHARP_SUPPORT_VLAN + if (type == PP_HTONS(ETHTYPE_VLAN)) { + struct eth_vlan_hdr *vlan = (struct eth_vlan_hdr*)(((char*)ethhdr) + SIZEOF_ETH_HDR); + if (p->len <= SIZEOF_ETH_HDR + SIZEOF_VLAN_HDR) { + /* a packet with only an ethernet/vlan header (or less) is not valid for us */ + ETHARP_STATS_INC(etharp.proterr); + ETHARP_STATS_INC(etharp.drop); + goto free_and_return; + } +#ifdef ETHARP_VLAN_CHECK /* if not, allow all VLANs */ + if (VLAN_ID(vlan) != ETHARP_VLAN_CHECK) { + /* silently ignore this packet: not for our VLAN */ + pbuf_free(p); + return ERR_OK; + } +#endif /* ETHARP_VLAN_CHECK */ + type = vlan->tpid; + ip_hdr_offset = SIZEOF_ETH_HDR + SIZEOF_VLAN_HDR; + } +#endif /* ETHARP_SUPPORT_VLAN */ + +#if LWIP_ARP_FILTER_NETIF + netif = LWIP_ARP_FILTER_NETIF_FN(p, netif, htons(type)); +#endif /* LWIP_ARP_FILTER_NETIF*/ + + switch (type) { +#if LWIP_ARP + /* IP packet? */ + case PP_HTONS(ETHTYPE_IP): + if (!(netif->flags & NETIF_FLAG_ETHARP)) { + goto free_and_return; + } +#if ETHARP_TRUST_IP_MAC + /* update ARP table */ + etharp_ip_input(netif, p); +#endif /* ETHARP_TRUST_IP_MAC */ + /* skip Ethernet header */ + if(pbuf_header(p, -ip_hdr_offset)) { + LWIP_ASSERT("Can't move over header in packet", 0); + goto free_and_return; + } else { + /* pass to IP layer */ + ip_input(p, netif); + } + break; + + case PP_HTONS(ETHTYPE_ARP): + if (!(netif->flags & NETIF_FLAG_ETHARP)) { + goto free_and_return; + } + /* pass p to ARP module */ + etharp_arp_input(netif, (struct eth_addr*)(netif->hwaddr), p); + break; +#endif /* LWIP_ARP */ +#if PPPOE_SUPPORT + case PP_HTONS(ETHTYPE_PPPOEDISC): /* PPP Over Ethernet Discovery Stage */ + pppoe_disc_input(netif, p); + break; + + case PP_HTONS(ETHTYPE_PPPOE): /* PPP Over Ethernet Session Stage */ + pppoe_data_input(netif, p); + break; +#endif /* PPPOE_SUPPORT */ + + default: + ETHARP_STATS_INC(etharp.proterr); + ETHARP_STATS_INC(etharp.drop); + goto free_and_return; + } + + /* This means the pbuf is freed or consumed, + so the caller doesn't have to free it again */ + return ERR_OK; + +free_and_return: + pbuf_free(p); + return ERR_OK; +} +#endif /* LWIP_ARP || LWIP_ETHERNET */ |