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minix/lib/liblwip/netif/etharp.c
Tomas Hruby 566af1516a LIBLWIP - ARP fix 
- does not crash KVM anymore
2013-03-25 16:51:25 +01:00

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/**
* @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"
#include "lwip/ip6.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}};
/** The 24-bit IANA multicast OUI is 01-00-5e: */
#define LL_MULTICAST_ADDR_0 0x01
#define LL_MULTICAST_ADDR_1 0x00
#define LL_MULTICAST_ADDR_2 0x5e
#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
/** Re-request a used ARP entry 1 minute before it would expire to prevent
* breaking a steadily used connection because the ARP entry timed out. */
#define ARP_AGE_REREQUEST_USED (ARP_MAXAGE - 12)
/** 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,
ETHARP_STATE_STABLE_REREQUESTING
#if ETHARP_SUPPORT_STATIC_ENTRIES
,ETHARP_STATE_STATIC
#endif /* ETHARP_SUPPORT_STATIC_ENTRIES */
};
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 netif *netif;
struct eth_addr ethaddr;
u8_t state;
u8_t ctime;
};
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
#if ETHARP_SUPPORT_STATIC_ENTRIES
#define ETHARP_FLAG_STATIC_ENTRY 4
#endif /* ETHARP_SUPPORT_STATIC_ENTRIES */
#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 */
/* 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
etharp_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_free_entry: 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;
#ifdef LWIP_DEBUG
/* for debugging, clean out the complete entry */
arp_table[i].ctime = 0;
arp_table[i].netif = NULL;
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
&& (state != ETHARP_STATE_STATIC)
#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 */
etharp_free_entry(i);
}
else if (arp_table[i].state == ETHARP_STATE_STABLE_REREQUESTING) {
/* Reset state to stable, so that the next transmitted packet will
re-send an ARP request. */
arp_table[i].state = ETHARP_STATE_STABLE;
}
#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
etharp_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, ("etharp_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, ("etharp_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 (state < ETHARP_STATE_STATIC)
#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, ("etharp_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, ("etharp_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, ("etharp_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, ("etharp_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 etharp_free_entry) */
i = old_queue;
LWIP_DEBUGF(ETHARP_DEBUG | LWIP_DBG_TRACE, ("etharp_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, ("etharp_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);
etharp_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;
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(&ethhdr->dest, dst);
ETHADDR16_COPY(&ethhdr->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
etharp_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, ("etharp_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, ("etharp_update_arp_entry: will not add non-unicast IP address to ARP cache\n"));
return ERR_ARG;
}
/* find or create ARP entry */
i = etharp_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].state = ETHARP_STATE_STATIC;
} else
#endif /* ETHARP_SUPPORT_STATIC_ENTRIES */
{
/* mark it stable */
arp_table[i].state = ETHARP_STATE_STABLE;
}
/* record network interface */
arp_table[i].netif = netif;
/* insert in SNMP ARP index tree */
snmp_insert_arpidx_tree(netif, &arp_table[i].ipaddr);
LWIP_DEBUGF(ETHARP_DEBUG | LWIP_DBG_TRACE, ("etharp_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 etharp_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 = etharp_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_STATIC) {
/* entry wasn't a static entry, cannot remove it */
return ERR_ARG;
}
/* entry found, free it */
etharp_free_entry(i);
return ERR_OK;
}
#endif /* ETHARP_SUPPORT_STATIC_ENTRIES */
/**
* Remove all ARP table entries of the specified netif.
*
* @param netif points to a network interface
*/
void etharp_cleanup_netif(struct netif *netif)
{
u8_t i;
for (i = 0; i < ARP_TABLE_SIZE; ++i) {
u8_t state = arp_table[i].state;
if ((state != ETHARP_STATE_EMPTY) && (arp_table[i].netif == netif)) {
etharp_free_entry(i);
}
}
}
/**
* 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 = etharp_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. */
etharp_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 */
etharp_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(&ethhdr->dest, ethdst_hwaddr);
#else /* LWIP_AUTOIP */
ETHADDR16_COPY(&ethhdr->dest, &hdr->shwaddr);
#endif /* LWIP_AUTOIP */
ETHADDR16_COPY(&hdr->shwaddr, ethaddr);
ETHADDR16_COPY(&ethhdr->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);
}
/** Just a small helper function that sends a pbuf to an ethernet address
* in the arp_table specified by the index 'arp_idx'.
*/
static err_t
etharp_output_to_arp_index(struct netif *netif, struct pbuf *q, u8_t arp_idx)
{
LWIP_ASSERT("arp_table[arp_idx].state >= ETHARP_STATE_STABLE",
arp_table[arp_idx].state >= ETHARP_STATE_STABLE);
/* if arp table entry is about to expire: re-request it,
but only if its state is ETHARP_STATE_STABLE to prevent flooding the
network with ARP requests if this address is used frequently. */
if ((arp_table[arp_idx].state == ETHARP_STATE_STABLE) &&
(arp_table[arp_idx].ctime >= ARP_AGE_REREQUEST_USED)) {
if (etharp_request(netif, &arp_table[arp_idx].ipaddr) == ERR_OK) {
arp_table[arp_idx].state = ETHARP_STATE_STABLE_REREQUESTING;
}
}
return etharp_send_ip(netif, q, (struct eth_addr*)(netif->hwaddr),
&arp_table[arp_idx].ethaddr);
}
/**
* 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;
struct eth_addr mcastaddr;
ip_addr_t *dst_addr = ipaddr;
LWIP_ASSERT("netif != NULL", netif != NULL);
LWIP_ASSERT("q != NULL", q != NULL);
LWIP_ASSERT("ipaddr != NULL", ipaddr != NULL);
/* 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;
}
/* 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 *)&ethbroadcast;
/* multicast destination IP address? */
} else if (ip_addr_ismulticast(ipaddr)) {
/* Hash IP multicast address to MAC address.*/
mcastaddr.addr[0] = LL_MULTICAST_ADDR_0;
mcastaddr.addr[1] = LL_MULTICAST_ADDR_1;
mcastaddr.addr[2] = LL_MULTICAST_ADDR_2;
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 {
s8_t i;
/* outside local network? if so, this can neither be a global broadcast nor
a subnet broadcast. */
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 */
dst_addr = &(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(dst_addr, &arp_table[etharp_cached_entry].ipaddr))) {
/* the per-pcb-cached entry is stable and the right one! */
ETHARP_STATS_INC(etharp.cachehit);
return etharp_output_to_arp_index(netif, q, etharp_cached_entry);
}
#if LWIP_NETIF_HWADDRHINT
}
}
#endif /* LWIP_NETIF_HWADDRHINT */
/* find stable entry: do this here since this is a critical path for
throughput and etharp_find_entry() is kind of slow */
for (i = 0; i < ARP_TABLE_SIZE; i++) {
if ((arp_table[i].state >= ETHARP_STATE_STABLE) &&
(ip_addr_cmp(dst_addr, &arp_table[i].ipaddr))) {
/* found an existing, stable entry */
ETHARP_SET_HINT(netif, i);
return etharp_output_to_arp_index(netif, q, i);
}
}
/* no stable entry found, use the (slower) query function:
queue on destination Ethernet address belonging to ipaddr */
return etharp_query(netif, dst_addr, 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 = etharp_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 */
LWIP_ASSERT("netif != NULL", netif != NULL);
/* Do not send ARP if the source IP is not set. This may cause various
* problems, for instance, triggers an assert in qemu-kvm */
if (ipsrc_addr->addr == 0)
return ERR_OK;
/* 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(&ethhdr->dest, ethdst_hwaddr);
#else /* LWIP_AUTOIP */
ETHADDR16_COPY(&ethhdr->dest, ethdst_addr);
#endif /* LWIP_AUTOIP */
ETHADDR16_COPY(&ethhdr->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, &ethbroadcast,
(struct eth_addr *)netif->hwaddr, &netif->ip_addr, &ethzero,
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;
#if LWIP_ARP || ETHARP_SUPPORT_VLAN
s16_t ip_hdr_offset = SIZEOF_ETH_HDR;
#endif /* LWIP_ARP || ETHARP_SUPPORT_VLAN */
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;
}
#if defined(ETHARP_VLAN_CHECK) || defined(ETHARP_VLAN_CHECK_FN) /* if not, allow all VLANs */
#ifdef ETHARP_VLAN_CHECK_FN
if (!ETHARP_VLAN_CHECK_FN(ethhdr, vlan)) {
#elif defined(ETHARP_VLAN_CHECK)
if (VLAN_ID(vlan) != ETHARP_VLAN_CHECK) {
#endif
/* silently ignore this packet: not for our VLAN */
pbuf_free(p);
return ERR_OK;
}
#endif /* defined(ETHARP_VLAN_CHECK) || defined(ETHARP_VLAN_CHECK_FN) */
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*/
if (ethhdr->dest.addr[0] & 1) {
/* this might be a multicast or broadcast packet */
if (ethhdr->dest.addr[0] == LL_MULTICAST_ADDR_0) {
if ((ethhdr->dest.addr[1] == LL_MULTICAST_ADDR_1) &&
(ethhdr->dest.addr[2] == LL_MULTICAST_ADDR_2)) {
/* mark the pbuf as link-layer multicast */
p->flags |= PBUF_FLAG_LLMCAST;
}
} else if (eth_addr_cmp(&ethhdr->dest, &ethbroadcast)) {
/* mark the pbuf as link-layer broadcast */
p->flags |= PBUF_FLAG_LLBCAST;
}
}
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 */
#if LWIP_IPV6
case PP_HTONS(ETHTYPE_IPV6): /* IPv6 */
/* skip Ethernet header */
if(pbuf_header(p, -(s16_t)SIZEOF_ETH_HDR)) {
LWIP_ASSERT("Can't move over header in packet", 0);
goto free_and_return;
} else {
/* pass to IPv6 layer */
ip6_input(p, netif);
}
break;
#endif /* LWIP_IPV6 */
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 */
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