err_t etharp_request(struct netif *netif, struct ip_addr *ipaddr)
{
struct pbuf *p;
struct eth_addr * srcaddr = (struct eth_addr *)netif->hwaddr;
err_t result = ERR_OK;
u8_t k; /* ARP entry index */
/* allocate a pbuf for the outgoing ARP request packet */
p = pbuf_alloc(PBUF_LINK, sizeof(struct etharp_hdr), PBUF_RAM);
/* could allocate a pbuf for an ARP request? */
if (p != NULL) {
struct etharp_hdr *hdr = p->payload;
LWIP_DEBUGF(ETHARP_DEBUG | DBG_TRACE, ("etharp_request: sending ARP request.\n"));
hdr->opcode = htons(ARP_REQUEST);
k = netif->hwaddr_len;
while(k > 0) {
k--;
hdr->shwaddr.addr[k] = srcaddr->addr[k];
/* the hardware address is what we ask for, in
* a request it is a don't-care value, we use zeroes */
hdr->dhwaddr.addr[k] = 0x00;
}
hdr->dipaddr = *(struct ip_addr2 *)ipaddr;
hdr->sipaddr = *(struct ip_addr2 *)&netif->ip_addr;
hdr->hwtype = htons(HWTYPE_ETHERNET);
ARPH_HWLEN_SET(hdr, netif->hwaddr_len);
hdr->proto = htons(ETHTYPE_IP);
ARPH_PROTOLEN_SET(hdr, sizeof(struct ip_addr));
k = netif->hwaddr_len;
while(k > 0) {
k--;
/* broadcast to all network interfaces on the local network */
hdr->ethhdr.dest.addr[k] = 0xff;
hdr->ethhdr.src.addr[k] = srcaddr->addr[k];
}
hdr->ethhdr.type = htons(ETHTYPE_ARP);
/* send ARP query */
result = netif->linkoutput(netif, p);
/* free ARP query packet */
pbuf_free(p);
p = NULL;
/* could not allocate pbuf for ARP request */
} else {
result = ERR_MEM;
LWIP_DEBUGF(ETHARP_DEBUG | DBG_TRACE | 2, ("etharp_request: could not allocate pbuf for ARP request.\n"));
}
return result;
}
/**
* 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 pbuf The ARP packet that arrived on netif. Is freed by this function.
* @param ethaddr Ethernet address of netif.
*
* @return NULL
*
* @see pbuf_free()
*/
void
etharp_arp_input(struct netif *netif, struct eth_addr *ethaddr, struct pbuf *p)
{
struct etharp_hdr *hdr;
/* these are aligned properly, whereas the ARP header fields might not be */
struct ip_addr sipaddr, dipaddr;
u8_t i;
u8_t for_us;
LWIP_ASSERT("netif != NULL", netif != NULL);
/* drop short ARP packets */
if (p->tot_len < sizeof(struct etharp_hdr)) {
LWIP_DEBUGF(ETHARP_DEBUG | DBG_TRACE | 1, ("etharp_arp_input: packet dropped, too short (%"S16_F"/%"S16_F")\n", p->tot_len, sizeof(struct etharp_hdr)));
pbuf_free(p);
return;
}
hdr = p->payload;
/* get aligned copies of addresses */
*(struct ip_addr2 *)&sipaddr = hdr->sipaddr;
*(struct ip_addr2 *)&dipaddr = hdr->dipaddr;
/* this interface is not configured? */
if (netif->ip_addr.addr == 0) {
for_us = 0;
} else {
/* ARP packet directed to us? */
for_us = ip_addr_cmp(&dipaddr, &(netif->ip_addr));
}
/* ARP message directed to us? */
if (for_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. */
update_arp_entry(netif, &sipaddr, &(hdr->shwaddr), ETHARP_TRY_HARD);
/* ARP message not directed to us? */
} else {
/* update the source IP address in the cache, if present */
update_arp_entry(netif, &sipaddr, &(hdr->shwaddr), 0);
}
/* now act on the message itself */
switch (htons(hdr->opcode)) {
/* ARP request? */
case 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 | DBG_TRACE, ("etharp_arp_input: incoming ARP request\n"));
/* ARP request for our address? */
if (for_us) {
LWIP_DEBUGF(ETHARP_DEBUG | DBG_TRACE, ("etharp_arp_input: replying to ARP request for our IP address\n"));
/* re-use pbuf to send ARP reply */
hdr->opcode = htons(ARP_REPLY);
hdr->dipaddr = hdr->sipaddr;
hdr->sipaddr = *(struct ip_addr2 *)&netif->ip_addr;
for(i = 0; i < netif->hwaddr_len; ++i) {
hdr->dhwaddr.addr[i] = hdr->shwaddr.addr[i];
hdr->shwaddr.addr[i] = ethaddr->addr[i];
hdr->ethhdr.dest.addr[i] = hdr->dhwaddr.addr[i];
hdr->ethhdr.src.addr[i] = ethaddr->addr[i];
}
hdr->hwtype = htons(HWTYPE_ETHERNET);
ARPH_HWLEN_SET(hdr, netif->hwaddr_len);
hdr->proto = htons(ETHTYPE_IP);
ARPH_PROTOLEN_SET(hdr, sizeof(struct ip_addr));
hdr->ethhdr.type = htons(ETHTYPE_ARP);
/* return ARP reply */
netif->linkoutput(netif, p);
/* we are not configured? */
} else if (netif->ip_addr.addr == 0) {
/* { for_us == 0 and netif->ip_addr.addr == 0 } */
LWIP_DEBUGF(ETHARP_DEBUG | 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 | DBG_TRACE, ("etharp_arp_input: ARP request was not for us.\n"));
}
break;
case ARP_REPLY:
/* ARP reply. We already updated the ARP cache earlier. */
LWIP_DEBUGF(ETHARP_DEBUG | 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
break;
default:
LWIP_DEBUGF(ETHARP_DEBUG | DBG_TRACE, ("etharp_arp_input: ARP unknown opcode type %"S16_F"\n", htons(hdr->opcode)));
break;
}
/* free ARP packet */
pbuf_free(p);
}
/*-----------------------------------------------------------------------------------*/
struct pbuf *
etharp_output(struct netif *netif, struct ip_addr *ipaddr, struct pbuf *q)
{
struct eth_addr *dest, *srcaddr, mcastaddr;
struct eth_hdr *ethhdr;
struct etharp_hdr *hdr;
struct pbuf *p;
u8_t i;
srcaddr = (struct eth_addr *)netif->hwaddr;
/* Make room for Ethernet header. */
if(pbuf_header(q, sizeof(struct eth_hdr)) != 0) {
/* The pbuf_header() call shouldn't fail, and we'll just bail
out if it does.. */
DEBUGF(ETHARP_DEBUG, ("etharp_output: could not allocate room for header.\n"));
#ifdef LINK_STATS
++stats.link.lenerr;
#endif /* LINK_STATS */
return NULL;
}
dest = NULL;
/* Construct Ethernet header. Start with looking up deciding which
MAC address to use as a destination address. Broadcasts and
multicasts are special, all other addresses are looked up in the
ARP table. */
if(ip_addr_isany(ipaddr) ||
ip_addr_isbroadcast(ipaddr, &(netif->netmask))) {
dest = (struct eth_addr *)ðbroadcast;
} else if(ip_addr_ismulticast(ipaddr)) {
/* Hash IP multicast address to MAC address. */
mcastaddr.addr[0] = 0x01;
mcastaddr.addr[1] = 0x0;
mcastaddr.addr[2] = 0x5e;
mcastaddr.addr[3] = ip4_addr2(ipaddr) & 0x7f;
mcastaddr.addr[4] = ip4_addr3(ipaddr);
mcastaddr.addr[5] = ip4_addr4(ipaddr);
dest = &mcastaddr;
} else {
#ifdef __PAULOS__
/* abort on insane conditions */
if (!ip_addr_maskcmp(ipaddr, &(netif->ip_addr), &(netif->netmask)))
return NULL;
if (ipaddr->addr == netif->ip_addr.addr)
return NULL;
#else
if(!ip_addr_maskcmp(ipaddr, &(netif->ip_addr), &(netif->netmask))) {
/* Use the IP address of the default gateway if the destination
is NOT on the same subnet as we are. ("NOT" added 20021113 psheer@) */
ipaddr = &(netif->gw);
}
#endif
/* We try to find a stable mapping. */
for(i = 0; i < arp_table_last; ++i) {
if((arp_table[i].state == ETHARP_STATE_STABLE || arp_table[i].state == ETHARP_STATE_STATIC) &&
ip_addr_cmp(ipaddr, &arp_table[i].ipaddr)) {
dest = &arp_table[i].ethaddr;
#if 0
// FIXME: remove this test code
if (!((int) rand() % 2)) {
dest = NULL;
arp_table[i].state = ETHARP_STATE_EMPTY;
if (arp_table[i].p)
pbuf_free (arp_table[i].p);
arp_table[i].p = NULL;
arp_table[i].payload = NULL;
arp_table[i].len = arp_table[0].tot_len = 0;
}
#endif
break;
}
}
}
if(dest == NULL) {
/* No destination address has been found, so we'll have to send
out an ARP request for the IP address. The outgoing packet is
queued unless the queue is full. */
/* We check if we are already querying for this address. If so,
we'll bail out. */
for(i = 0; i < arp_table_last; ++i) {
if(arp_table[i].state == ETHARP_STATE_PENDING &&
ip_addr_cmp(ipaddr, &arp_table[i].ipaddr)) {
DEBUGF(ETHARP_DEBUG, ("etharp_output: already queued\n"));
return NULL;
}
}
hdr = q->payload;
for(i = 0; i < 6; ++i)
hdr->ethhdr.src.addr[i] = srcaddr->addr[i];
hdr->ethhdr.type = htons(ETHTYPE_IP);
i = etharp_new_entry(q, ipaddr, NULL, ETHARP_STATE_PENDING);
/* We allocate a pbuf for the outgoing ARP request packet. */
p = pbuf_alloc(PBUF_RAW, sizeof(struct etharp_hdr) + 2, PBUF_RAM);
if(p == NULL) {
/* No ARP request packet could be allocated, so we forget about
the ARP table entry. */
if(i != ARP_TABLE_SIZE) {
arp_table[i].state = ETHARP_STATE_EMPTY;
/* We decrease the reference count of the queued pbuf (which now
is dequeued). */
DEBUGF(ETHARP_DEBUG, ("etharp_output: couldn't alloc pbuf for query, dequeueing %p\n", q));
}
return NULL;
}
pbuf_header (p, (s16_t) -2);
hdr = p->payload;
hdr->opcode = htons(ARP_REQUEST);
for(i = 0; i < 6; ++i) {
hdr->dhwaddr.addr[i] = 0x00;
hdr->shwaddr.addr[i] = srcaddr->addr[i];
}
memcpy (&(hdr->dipaddr), ipaddr, sizeof (hdr->dipaddr));
memcpy (&(hdr->sipaddr), &(netif->ip_addr), sizeof (hdr->sipaddr));
hdr->hwtype = htons(HWTYPE_ETHERNET);
ARPH_HWLEN_SET(hdr, 6);
hdr->proto = htons(ETHTYPE_IP);
ARPH_PROTOLEN_SET(hdr, sizeof(struct ip_addr));
for(i = 0; i < 6; ++i) {
hdr->ethhdr.dest.addr[i] = 0xff;
hdr->ethhdr.src.addr[i] = srcaddr->addr[i];
}
hdr->ethhdr.type = htons(ETHTYPE_ARP);
return p; /* (1) */
} else {
/* A valid IP->MAC address mapping was found, so we construct the
Ethernet header for the outgoing packet. */
ethhdr = q->payload;
for(i = 0; i < 6; i++) {
ethhdr->dest.addr[i] = dest->addr[i];
ethhdr->src.addr[i] = srcaddr->addr[i];
}
ethhdr->type = htons(ETHTYPE_IP);
pbuf_ref (q); /* <--- this is important, because the reference
must parallel that when returning over here (1). Callers must then
ALWAYS do a pbuf_free on the return value of etharp_output(). */
return q;
}
}
/*-----------------------------------------------------------------------------------*/
struct pbuf *
etharp_arp_input(struct netif *netif, struct eth_addr *ethaddr, struct pbuf *p, struct pbuf **queued)
{
struct etharp_hdr *hdr;
u8_t i;
if(p->tot_len < sizeof(struct etharp_hdr)) {
DEBUGF(ETHARP_DEBUG, ("etharp_etharp_input: packet too short (%d/%d)\n", (int) p->tot_len, (int) sizeof(struct etharp_hdr)));
return NULL;
}
hdr = p->payload;
switch(htons(hdr->opcode)) {
case ARP_REQUEST:
*queued = update_arp_entry(&(hdr->sipaddr), &(hdr->shwaddr), 0);
/* ARP request. If it asked for our address, we send out a
reply. */
DEBUGF(ETHARP_DEBUG, ("etharp_arp_input: ARP request\n"));
if(!memcmp(&(hdr->dipaddr), &(netif->ip_addr), sizeof (hdr->dipaddr))) {
pbuf_ref(p);
hdr->opcode = htons(ARP_REPLY);
memcpy (&(hdr->dipaddr), &(hdr->sipaddr), sizeof (hdr->dipaddr));
memcpy (&(hdr->sipaddr), &(netif->ip_addr), sizeof (hdr->sipaddr));
for(i = 0; i < 6; ++i) {
hdr->dhwaddr.addr[i] = hdr->shwaddr.addr[i];
hdr->shwaddr.addr[i] = ethaddr->addr[i];
hdr->ethhdr.dest.addr[i] = hdr->dhwaddr.addr[i];
hdr->ethhdr.src.addr[i] = ethaddr->addr[i];
}
hdr->hwtype = htons(HWTYPE_ETHERNET);
ARPH_HWLEN_SET(hdr, 6);
hdr->proto = htons(ETHTYPE_IP);
ARPH_PROTOLEN_SET(hdr, sizeof(struct ip_addr));
hdr->ethhdr.type = htons(ETHTYPE_ARP);
return p;
}
break;
case ARP_REPLY:
/* ARP reply. We insert or update the ARP table. */
DEBUGF(ETHARP_DEBUG, ("etharp_arp_input: ARP reply\n"));
if(!memcmp (&(hdr->dipaddr), &(netif->ip_addr), sizeof (hdr->dipaddr))) {
#if (LWIP_DHCP && DHCP_DOES_ARP_CHECK)
dhcp_arp_reply(&hdr->sipaddr);
#endif
/* add_arp_entry() will return a pbuf that has previously been
queued waiting for an ARP reply. */
}
/* whether its destined for us or not, we update the arp table */
return add_arp_entry(&(hdr->sipaddr), &(hdr->shwaddr));
break;
default:
DEBUGF(ETHARP_DEBUG, ("etharp_arp_input: unknown type %d\n", htons(hdr->opcode)));
break;
}
return NULL;
}
/**
* Send an ARP request for the given IP address.
*
* Sends an ARP request for the given IP address, unless
* a request for this address is already pending. Optionally
* queues an outgoing packet on the resulting ARP entry.
*
* @param netif The lwIP network interface where ipaddr
* must be queried for.
* @param ipaddr The IP address to be resolved.
* @param q If non-NULL, a pbuf that must be queued on the
* ARP entry for the ipaddr IP address.
*
* @return NULL.
*
* @note Might be used in the future by manual IP configuration
* as well.
*
* TODO: use the ctime field to see how long ago an ARP request was sent,
* possibly retry.
*/
err_t etharp_query(struct netif *netif, struct ip_addr *ipaddr, struct pbuf *q)
{
struct eth_addr *srcaddr;
struct etharp_hdr *hdr;
struct pbuf *p;
err_t result = ERR_OK;
u8_t i;
u8_t perform_arp_request = 1;
/* prevent 'unused argument' warning if ARP_QUEUEING == 0 */
(void)q;
srcaddr = (struct eth_addr *)netif->hwaddr;
/* bail out if this IP address is pending */
for (i = 0; i < ARP_TABLE_SIZE; ++i) {
if (ip_addr_cmp(ipaddr, &arp_table[i].ipaddr)) {
if (arp_table[i].state == ETHARP_STATE_PENDING) {
DEBUGF(ETHARP_DEBUG | DBG_TRACE | DBG_STATE, ("etharp_query: requested IP already pending as entry %u\n", i));
/* break out of for-loop, user may wish to queue a packet on a stable entry */
/* TODO: we will issue a new ARP request, which should not occur too often */
/* we might want to run a faster timer on ARP to limit this */
break;
}
else if (arp_table[i].state == ETHARP_STATE_STABLE) {
DEBUGF(ETHARP_DEBUG | DBG_TRACE | DBG_STATE, ("etharp_query: requested IP already stable as entry %u\n", i));
/* user may wish to queue a packet on a stable entry, so we proceed without ARP requesting */
/* TODO: even if the ARP entry is stable, we might do an ARP request anyway */
perform_arp_request = 0;
break;
}
}
}
/* queried address not yet in ARP table? */
if (i == ARP_TABLE_SIZE) {
DEBUGF(ETHARP_DEBUG | DBG_TRACE, ("etharp_query: IP address not found in ARP table\n"));
/* find an available entry */
i = find_arp_entry();
/* bail out if no ARP entries are available */
if (i == ARP_TABLE_SIZE) {
DEBUGF(ETHARP_DEBUG | 2, ("etharp_query: no more ARP entries available.\n"));
return ERR_MEM;
}
/* we will now recycle entry i */
DEBUGF(ETHARP_DEBUG | DBG_TRACE, ("etharp_query: created ARP table entry %u.\n", i));
/* i is available, create ARP entry */
ip_addr_set(&arp_table[i].ipaddr, ipaddr);
arp_table[i].ctime = 0;
arp_table[i].state = ETHARP_STATE_PENDING;
#if ARP_QUEUEING
/* free queued packet, as entry is now invalidated */
if (arp_table[i].p != NULL) {
pbuf_free(arp_table[i].p);
arp_table[i].p = NULL;
DEBUGF(ETHARP_DEBUG | DBG_TRACE | 3, ("etharp_query: dropped packet on ARP queue. Should not occur.\n"));
}
#endif
}
#if ARP_QUEUEING
/* any pbuf to queue and queue is empty? */
if (q != NULL) {
/* yield later packets over older packets? */
#if ARP_QUEUE_FIRST == 0
/* earlier queued packet on this entry? */
if (arp_table[i].p != NULL) {
pbuf_free(arp_table[i].p);
arp_table[i].p = NULL;
DEBUGF(ETHARP_DEBUG | DBG_TRACE | 3, ("etharp_query: dropped packet on ARP queue. Should not occur.\n"));
/* fall-through into next if */
}
#endif
/* packet can be queued? */
if (arp_table[i].p == NULL) {
/* copy PBUF_REF referenced payloads into PBUF_RAM */
q = pbuf_take(q);
/* remember pbuf to queue, if any */
arp_table[i].p = q;
/* pbufs are queued, increase the reference count */
pbuf_ref(q);
DEBUGF(ETHARP_DEBUG | DBG_TRACE | DBG_STATE, ("etharp_query: queued packet %p on ARP entry %u.\n", (void *)q, i));
}
}
#endif
/* ARP request? */
if (perform_arp_request)
{
/* allocate a pbuf for the outgoing ARP request packet */
p = pbuf_alloc(PBUF_LINK, sizeof(struct etharp_hdr), PBUF_RAM);
/* could allocate pbuf? */
if (p != NULL) {
u8_t j;
DEBUGF(ETHARP_DEBUG | DBG_TRACE, ("etharp_query: sending ARP request.\n"));
hdr = p->payload;
hdr->opcode = htons(ARP_REQUEST);
for(j = 0; j < netif->hwaddr_len; ++j)
{
hdr->dhwaddr.addr[j] = 0x00;
hdr->shwaddr.addr[j] = srcaddr->addr[j];
}
ip_addr_set(&(hdr->dipaddr), ipaddr);
ip_addr_set(&(hdr->sipaddr), &(netif->ip_addr));
hdr->hwtype = htons(HWTYPE_ETHERNET);
ARPH_HWLEN_SET(hdr, netif->hwaddr_len);
hdr->proto = htons(ETHTYPE_IP);
ARPH_PROTOLEN_SET(hdr, sizeof(struct ip_addr));
for(j = 0; j < netif->hwaddr_len; ++j)
{
hdr->ethhdr.dest.addr[j] = 0xff;
hdr->ethhdr.src.addr[j] = srcaddr->addr[j];
}
hdr->ethhdr.type = htons(ETHTYPE_ARP);
/* send ARP query */
result = netif->linkoutput(netif, p);
/* free ARP query packet */
pbuf_free(p);
p = NULL;
} else {
result = ERR_MEM;
DEBUGF(ETHARP_DEBUG | DBG_TRACE | 2, ("etharp_query: could not allocate pbuf for ARP request.\n"));
}
}
return result;
}
/**
* Responds to ARP requests, updates ARP entries and sends queued IP packets.
*
* 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 pbuf The ARP packet that arrived on netif. Is freed by this function.
* @param ethaddr Ethernet address of netif.
*
* @return NULL
*
* @see pbuf_free()
*/
struct pbuf *
etharp_arp_input(struct netif *netif, struct eth_addr *ethaddr, struct pbuf *p)
{
struct etharp_hdr *hdr;
u8_t i;
/* drop short ARP packets */
if (p->tot_len < sizeof(struct etharp_hdr)) {
DEBUGF(ETHARP_DEBUG | DBG_TRACE | 1, ("etharp_arp_input: packet too short (%ld/%u)\n", p->tot_len, sizeof(struct etharp_hdr)));
pbuf_free(p);
return NULL;
}
hdr = p->payload;
switch (htons(hdr->opcode)) {
/* ARP request? */
case 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. */
DEBUGF (ETHARP_DEBUG | DBG_TRACE, ("etharp_arp_input: incoming ARP request\n"));
/* we are not configured? */
if (netif->ip_addr.addr == 0) {
DEBUGF(ETHARP_DEBUG | DBG_TRACE, ("etharp_arp_input: we are unconfigured, ARP request ignored.\n"));
pbuf_free(p);
return NULL;
}
/* update the ARP cache */
update_arp_entry(netif, &(hdr->sipaddr), &(hdr->shwaddr), 0);
/* ARP request for our address? */
if (ip_addr_cmp(&(hdr->dipaddr), &(netif->ip_addr))) {
DEBUGF(ETHARP_DEBUG | DBG_TRACE, ("etharp_arp_input: replying to ARP request for our IP address\n"));
/* re-use pbuf to send ARP reply */
hdr->opcode = htons(ARP_REPLY);
ip_addr_set(&(hdr->dipaddr), &(hdr->sipaddr));
ip_addr_set(&(hdr->sipaddr), &(netif->ip_addr));
for(i = 0; i < netif->hwaddr_len; ++i) {
hdr->dhwaddr.addr[i] = hdr->shwaddr.addr[i];
hdr->shwaddr.addr[i] = ethaddr->addr[i];
hdr->ethhdr.dest.addr[i] = hdr->dhwaddr.addr[i];
hdr->ethhdr.src.addr[i] = ethaddr->addr[i];
}
hdr->hwtype = htons(HWTYPE_ETHERNET);
ARPH_HWLEN_SET(hdr, netif->hwaddr_len);
hdr->proto = htons(ETHTYPE_IP);
ARPH_PROTOLEN_SET(hdr, sizeof(struct ip_addr));
hdr->ethhdr.type = htons(ETHTYPE_ARP);
/* return ARP reply */
netif->linkoutput(netif, p);
} else {
DEBUGF(ETHARP_DEBUG | DBG_TRACE, ("etharp_arp_input: incoming ARP request was not for us.\n"));
}
break;
case ARP_REPLY:
/* ARP reply. We insert or update the ARP table. */
DEBUGF(ETHARP_DEBUG | DBG_TRACE, ("etharp_arp_input: incoming ARP reply\n"));
#if (LWIP_DHCP && DHCP_DOES_ARP_CHECK)
/* DHCP needs to know about ARP replies */
dhcp_arp_reply(netif, &hdr->sipaddr);
#endif
/* ARP reply directed to us? */
if (ip_addr_cmp(&(hdr->dipaddr), &(netif->ip_addr))) {
DEBUGF(ETHARP_DEBUG | DBG_TRACE, ("etharp_arp_input: incoming ARP reply is for us\n"));
/* update_the ARP cache, ask to insert */
update_arp_entry(netif, &(hdr->sipaddr), &(hdr->shwaddr), ARP_INSERT_FLAG);
/* ARP reply not directed to us */
} else {
DEBUGF(ETHARP_DEBUG | DBG_TRACE, ("etharp_arp_input: incoming ARP reply is not for us\n"));
/* update the destination address pair */
update_arp_entry(netif, &(hdr->sipaddr), &(hdr->shwaddr), 0);
/* update the destination address pair */
update_arp_entry(netif, &(hdr->dipaddr), &(hdr->dhwaddr), 0);
}
break;
default:
DEBUGF(ETHARP_DEBUG | DBG_TRACE, ("etharp_arp_input: ARP unknown opcode type %d\n", htons(hdr->opcode)));
break;
}
/* free ARP packet */
pbuf_free(p);
p = NULL;
/* nothing to send, we did it! */
return NULL;
}
/**
* Send an ARP request for the given IP address.
*
* Sends an ARP request for the given IP address, unless
* a request for this address is already pending. Optionally
* queues an outgoing packet on the resulting ARP entry.
*
* @param netif The lwIP network interface where ipaddr
* must be queried for.
* @param ipaddr The IP address to be resolved.
* @param q If non-NULL, a pbuf that must be queued on the
* ARP entry for the ipaddr IP address.
*
* @return NULL.
*
* @note Might be used in the future by manual IP configuration
* as well.
*
* TODO: use the ctime field to see how long ago an ARP request was sent,
* possibly retry.
*/
err_t etharp_query(struct netif *netif, struct ip_addr *ipaddr, struct pbuf *q)
{
struct eth_addr *srcaddr;
struct etharp_hdr *hdr;
err_t result = ERR_OK;
s8_t i;
u8_t perform_arp_request = 1;
/* prevent 'unused argument' warning if ARP_QUEUEING == 0 */
(void)q;
srcaddr = (struct eth_addr *)netif->hwaddr;
/* bail out if this IP address is pending */
for (i = 0; i < ARP_TABLE_SIZE; ++i) {
if (arp_table[i].state != ETHARP_STATE_EMPTY &&
ip_addr_cmp(ipaddr, &arp_table[i].ipaddr)) {
if (arp_table[i].state == ETHARP_STATE_PENDING) {
LWIP_DEBUGF(ETHARP_DEBUG | DBG_TRACE | DBG_STATE, ("etharp_query: requested IP already pending as entry %u\n", i));
/* break out of for-loop, user may wish to queue a packet on a pending entry */
/* TODO: we will issue a new ARP request, which should not occur too often */
/* we might want to run a faster timer on ARP to limit this */
break;
}
else if (arp_table[i].state == ETHARP_STATE_STABLE) {
LWIP_DEBUGF(ETHARP_DEBUG | DBG_TRACE | DBG_STATE, ("etharp_query: requested IP already stable as entry %u\n", i));
/* User wishes to queue a packet on a stable entry (or does she want to send
* out the packet immediately, we will not know), so we force an ARP request.
* Upon response we will send out the queued packet in etharp_update().
*
* Alternatively, we could accept the stable entry, and just send out the packet
* immediately. I chose to implement the former approach.
*/
perform_arp_request = (q?1:0);
break;
}
}
}
/* queried address not yet in ARP table? */
if (i == ARP_TABLE_SIZE) {
LWIP_DEBUGF(ETHARP_DEBUG | DBG_TRACE, ("etharp_query: IP address not found in ARP table\n"));
/* find an available (unused or old) entry */
i = find_arp_entry();
/* bail out if no ARP entries are available */
if (i == ERR_MEM) {
LWIP_DEBUGF(ETHARP_DEBUG | 2, ("etharp_query: no more ARP entries available. Should seldom occur.\n"));
return ERR_MEM;
}
/* i is available, create ARP entry */
arp_table[i].state = ETHARP_STATE_PENDING;
ip_addr_set(&arp_table[i].ipaddr, ipaddr);
}
/* { i is now valid } */
#if ARP_QUEUEING /* queue packet (even on a stable entry, see above) */
/* copy any PBUF_REF referenced payloads into PBUF_RAM */
q = pbuf_take(q);
pbuf_queue(arp_table[i].p, q);
#endif
/* ARP request? */
if (perform_arp_request)
{
struct pbuf *p;
/* allocate a pbuf for the outgoing ARP request packet */
p = pbuf_alloc(PBUF_LINK, sizeof(struct etharp_hdr), PBUF_RAM);
/* could allocate pbuf? */
if (p != NULL) {
u8_t j;
LWIP_DEBUGF(ETHARP_DEBUG | DBG_TRACE, ("etharp_query: sending ARP request.\n"));
hdr = p->payload;
hdr->opcode = htons(ARP_REQUEST);
for (j = 0; j < netif->hwaddr_len; ++j)
{
hdr->shwaddr.addr[j] = srcaddr->addr[j];
/* the hardware address is what we ask for, in
* a request it is a don't-care, we use 0's */
hdr->dhwaddr.addr[j] = 0x00;
}
hdr->dipaddr = *(struct ip_addr2 *)ipaddr;
hdr->sipaddr = *(struct ip_addr2 *)&netif->ip_addr;
hdr->hwtype = htons(HWTYPE_ETHERNET);
ARPH_HWLEN_SET(hdr, netif->hwaddr_len);
hdr->proto = htons(ETHTYPE_IP);
ARPH_PROTOLEN_SET(hdr, sizeof(struct ip_addr));
for (j = 0; j < netif->hwaddr_len; ++j)
{
hdr->ethhdr.dest.addr[j] = 0xff;
hdr->ethhdr.src.addr[j] = srcaddr->addr[j];
}
hdr->ethhdr.type = htons(ETHTYPE_ARP);
/* send ARP query */
result = netif->linkoutput(netif, p);
/* free ARP query packet */
pbuf_free(p);
p = NULL;
} else {
result = ERR_MEM;
LWIP_DEBUGF(ETHARP_DEBUG | DBG_TRACE | 2, ("etharp_query: could not allocate pbuf for ARP request.\n"));
}
}
return result;
}
/**
* 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 pbuf The ARP packet that arrived on netif. Is freed by this function.
* @param ethaddr Ethernet address of netif.
*
* @return NULL
*
* @see pbuf_free()
*/
void
etharp_arp_input(struct netif *netif, struct eth_addr *ethaddr, struct pbuf *p)
{
struct etharp_hdr *hdr;
/* these are aligned properly, whereas the ARP header fields might not be */
struct ip_addr sipaddr, dipaddr;
u8_t i;
u8_t for_us;
/* drop short ARP packets */
if (p->tot_len < sizeof(struct etharp_hdr)) {
LWIP_DEBUGF(ETHARP_DEBUG | DBG_TRACE | 1, ("etharp_arp_input: packet dropped, too short (%d/%d)\n", p->tot_len, sizeof(struct etharp_hdr)));
pbuf_free(p);
return;
}
hdr = p->payload;
/* get aligned copies of addresses */
*(struct ip_addr2 *)&sipaddr = hdr->sipaddr;
*(struct ip_addr2 *)&dipaddr = hdr->dipaddr;
/* this interface is not configured? */
if (netif->ip_addr.addr == 0) {
for_us = 0;
} else {
/* ARP packet directed to us? */
for_us = ip_addr_cmp(&dipaddr, &(netif->ip_addr));
}
/* ARP message directed to us? */
if (for_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. */
update_arp_entry(netif, &sipaddr, &(hdr->shwaddr), ETHARP_CREATE);
/* ARP message not directed to us? */
} else {
/* update the source IP address in the cache, if present */
update_arp_entry(netif, &sipaddr, &(hdr->shwaddr), 0);
}
/* now act on the message itself */
switch (htons(hdr->opcode)) {
/* ARP request? */
case 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 | DBG_TRACE, ("etharp_arp_input: incoming ARP request\n"));
/* ARP request for our address? */
if (for_us) {
LWIP_DEBUGF(ETHARP_DEBUG | DBG_TRACE, ("etharp_arp_input: replying to ARP request for our IP address\n"));
/* re-use pbuf to send ARP reply */
hdr->opcode = htons(ARP_REPLY);
hdr->dipaddr = hdr->sipaddr;
hdr->sipaddr = *(struct ip_addr2 *)&netif->ip_addr;
for(i = 0; i < netif->hwaddr_len; ++i) {
hdr->dhwaddr.addr[i] = hdr->shwaddr.addr[i];
hdr->shwaddr.addr[i] = ethaddr->addr[i];
hdr->ethhdr.dest.addr[i] = hdr->dhwaddr.addr[i];
hdr->ethhdr.src.addr[i] = ethaddr->addr[i];
}
hdr->hwtype = htons(HWTYPE_ETHERNET);
ARPH_HWLEN_SET(hdr, netif->hwaddr_len);
hdr->proto = htons(ETHTYPE_IP);
ARPH_PROTOLEN_SET(hdr, sizeof(struct ip_addr));
hdr->ethhdr.type = htons(ETHTYPE_ARP);
/* return ARP reply */
netif->linkoutput(netif, p);
#ifdef LINKLOCAL_IP //Ron Add for Rendzvous 12/10/04
if( mRENVEnable && (LinkLocal_get_current_state() != NO_USE )
&& is_linklocal_ip( dipaddr.addr ) )
{
if( (LinkLocal_get_current_state() != IDLE) && ip_conflict_cnt++ == 0 )
linklocal_alarm();
else if( (LinkLocal_get_current_state() == IDLE) && ip_conflict_cnt++ == 0)
{
linklocal_alarm();
}
}
#endif
/* we are not configured? */
} else if (netif->ip_addr.addr == 0) {
/* { for_us == 0 and netif->ip_addr.addr == 0 } */
#ifdef LINKLOCAL_IP //Ron Add for Rendzvous 12/10/04
if( mRENVEnable && (LinkLocal_get_current_state() != NO_USE )
&& is_linklocal_ip( dipaddr.addr ) )
{
if( (LinkLocal_get_current_state() != IDLE) && ip_conflict_cnt++ == 0 )
linklocal_alarm();
else if( (LinkLocal_get_current_state() == IDLE) && ip_conflict_cnt++ == 0)
{
linklocal_alarm();
}
hdr->opcode = htons(ARP_REPLY);
hdr->sipaddr = hdr->dipaddr;
hdr->dipaddr = *(struct ip_addr2 *)&netif->ip_addr;
// hdr->dipaddr = hdr->sipaddr;
// hdr->sipaddr = *(struct ip_addr2 *)&netif->ip_addr;
for(i = 0; i < netif->hwaddr_len; ++i) {
hdr->dhwaddr.addr[i] = hdr->shwaddr.addr[i];
hdr->shwaddr.addr[i] = ethaddr->addr[i];
hdr->ethhdr.dest.addr[i] = hdr->dhwaddr.addr[i];
hdr->ethhdr.src.addr[i] = ethaddr->addr[i];
}
hdr->hwtype = htons(HWTYPE_ETHERNET);
ARPH_HWLEN_SET(hdr, netif->hwaddr_len);
hdr->proto = htons(ETHTYPE_IP);
ARPH_PROTOLEN_SET(hdr, sizeof(struct ip_addr));
hdr->ethhdr.type = htons(ETHTYPE_ARP);
netif->linkoutput(netif, p);
}
#endif
LWIP_DEBUGF(ETHARP_DEBUG | 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 | DBG_TRACE, ("etharp_arp_input: ARP request was not for us.\n"));
}
break;
case ARP_REPLY:
/* ARP reply. We already updated the ARP cache earlier. */
LWIP_DEBUGF(ETHARP_DEBUG | DBG_TRACE, ("etharp_arp_input: incoming ARP reply\n"));
#if (LWIP_DHCP && DHCP_DOES_ARP_CHECK)
/* DHCP wants to know about ARP replies to our wanna-have-address */
if (for_us){
dhcp_arp_reply(netif, &sipaddr);
}
#endif
#ifdef LINKLOCAL_IP //Ron Add for Rendzvous 12/10/04
if( mRENVEnable && (LinkLocal_get_current_state() != NO_USE ) && is_linklocal_ip( sipaddr.addr ) )
{
if( (LinkLocal_get_current_state() != IDLE) && ip_conflict_cnt++ == 0 )
linklocal_alarm();
else if( (LinkLocal_get_current_state() == IDLE) && ip_conflict_cnt++ == 0)
{
linklocal_alarm();
}
}
#endif
break;
default:
LWIP_DEBUGF(ETHARP_DEBUG | DBG_TRACE, ("etharp_arp_input: ARP unknown opcode type %d\n", htons(hdr->opcode)));
break;
}
/* free ARP packet */
pbuf_free(p);
}
/**
* 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 pbuf The ARP packet that arrived on netif. Is freed by this function.
* @param ethaddr Ethernet address of netif.
*
* @return NULL
*
* @see pbuf_free()
*/
struct pbuf *
etharp_arp_input(struct netif *netif, struct eth_addr *ethaddr, struct pbuf *p)
{
struct etharp_hdr *hdr;
u8_t i;
u8_t for_us;
/* drop short ARP packets */
if (p->tot_len < sizeof(struct etharp_hdr)) {
LWIP_DEBUGF(ETHARP_DEBUG | DBG_TRACE | 1, ("etharp_arp_input: packet dropped, too short (%d/%d)\n", p->tot_len, sizeof(struct etharp_hdr)));
pbuf_free(p);
return NULL;
}
hdr = p->payload;
/* this interface is not configured? */
if (netif->ip_addr.addr == 0) {
for_us = 0;
} else {
/* ARP packet directed to us? */
for_us = ip_addr_cmp(&(hdr->dipaddr), &(netif->ip_addr));
}
/* add or update entries in the ARP cache */
if (for_us) {
/* insert IP address in ARP cache (assume requester wants to talk to us)
* we might even send out a queued packet to this host */
update_arp_entry(netif, &(hdr->sipaddr), &(hdr->shwaddr), ARP_INSERT_FLAG);
/* request was not directed to us, but snoop anyway */
} else {
/* update the source IP address in the cache */
update_arp_entry(netif, &(hdr->sipaddr), &(hdr->shwaddr), 0);
}
switch (htons(hdr->opcode)) {
/* ARP request? */
case 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 | DBG_TRACE, ("etharp_arp_input: incoming ARP request\n"));
/* we are not configured? */
if (netif->ip_addr.addr == 0) {
LWIP_DEBUGF(ETHARP_DEBUG | DBG_TRACE, ("etharp_arp_input: we are unconfigured, ARP request ignored.\n"));
pbuf_free(p);
return NULL;
}
/* ARP request for our address? */
if (for_us) {
LWIP_DEBUGF(ETHARP_DEBUG | DBG_TRACE, ("etharp_arp_input: replying to ARP request for our IP address\n"));
/* re-use pbuf to send ARP reply */
hdr->opcode = htons(ARP_REPLY);
ip_addr_set(&(hdr->dipaddr), &(hdr->sipaddr));
ip_addr_set(&(hdr->sipaddr), &(netif->ip_addr));
for(i = 0; i < netif->hwaddr_len; ++i) {
hdr->dhwaddr.addr[i] = hdr->shwaddr.addr[i];
hdr->shwaddr.addr[i] = ethaddr->addr[i];
hdr->ethhdr.dest.addr[i] = hdr->dhwaddr.addr[i];
hdr->ethhdr.src.addr[i] = ethaddr->addr[i];
}
hdr->hwtype = htons(HWTYPE_ETHERNET);
ARPH_HWLEN_SET(hdr, netif->hwaddr_len);
hdr->proto = htons(ETHTYPE_IP);
ARPH_PROTOLEN_SET(hdr, sizeof(struct ip_addr));
hdr->ethhdr.type = htons(ETHTYPE_ARP);
/* return ARP reply */
netif->linkoutput(netif, p);
/* request was not directed to us */
} else {
LWIP_DEBUGF(ETHARP_DEBUG | DBG_TRACE, ("etharp_arp_input: incoming ARP request was not for us.\n"));
}
break;
case ARP_REPLY:
/* ARP reply. We insert or update the ARP table later. */
LWIP_DEBUGF(ETHARP_DEBUG | DBG_TRACE, ("etharp_arp_input: incoming ARP reply\n"));
#if (LWIP_DHCP && DHCP_DOES_ARP_CHECK)
/* DHCP wants to know about ARP replies to our wanna-have-address */
if (for_us) dhcp_arp_reply(netif, &hdr->sipaddr);
#endif
break;
default:
LWIP_DEBUGF(ETHARP_DEBUG | DBG_TRACE, ("etharp_arp_input: ARP unknown opcode type %d\n", htons(hdr->opcode)));
break;
}
/* free ARP packet */
pbuf_free(p);
p = NULL;
/* nothing to send, we did it! */
return NULL;
}
