/**
* 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 @ref etharp_state
*
* @return
* - ERR_OK Successfully 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, const ip4_addr_t *ipaddr, struct eth_addr *ethaddr, u8_t flags)
{
s8_t i;
LWIP_ASSERT("netif->hwaddr_len == ETH_HWADDR_LEN", netif->hwaddr_len == ETH_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),
(u16_t)ethaddr->addr[0], (u16_t)ethaddr->addr[1], (u16_t)ethaddr->addr[2],
(u16_t)ethaddr->addr[3], (u16_t)ethaddr->addr[4], (u16_t)ethaddr->addr[5]));
/* non-unicast address? */
if (ip4_addr_isany(ipaddr) ||
ip4_addr_isbroadcast(ipaddr, netif) ||
ip4_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, netif);
/* 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 if (arp_table[i].state == ETHARP_STATE_STATIC) {
/* found entry is a static type, don't overwrite it */
return ERR_VAL;
} 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 */
mib2_add_arp_entry(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 */
ethernet_output(netif, p, (struct eth_addr*)(netif->hwaddr), ethaddr, ETHTYPE_IP);
/* 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(const ip4_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),
(u16_t)ethaddr->addr[0], (u16_t)ethaddr->addr[1], (u16_t)ethaddr->addr[2],
(u16_t)ethaddr->addr[3], (u16_t)ethaddr->addr[4], (u16_t)ethaddr->addr[5]));
netif = ip4_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(const ip4_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, NULL);
/* 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;
}
/**
* Processes ICMP input packets, called from ip_input().
*
* Currently only processes icmp echo requests and sends
* out the echo response.
*
* @param p the icmp echo request packet, p->payload pointing to the icmp header
* @param inp the netif on which this packet was received
*/
void
icmp_input(struct pbuf *p, struct netif *inp)
{
u8_t type;
#ifdef LWIP_DEBUG
u8_t code;
#endif /* LWIP_DEBUG */
struct icmp_echo_hdr *iecho;
const struct ip_hdr *iphdr_in;
s16_t hlen;
const ip4_addr_t* src;
ICMP_STATS_INC(icmp.recv);
MIB2_STATS_INC(mib2.icmpinmsgs);
iphdr_in = ip4_current_header();
hlen = IPH_HL(iphdr_in) * 4;
if (hlen < IP_HLEN) {
LWIP_DEBUGF(ICMP_DEBUG, ("icmp_input: short IP header (%"S16_F" bytes) received\n", hlen));
goto lenerr;
}
if (p->len < sizeof(u16_t)*2) {
LWIP_DEBUGF(ICMP_DEBUG, ("icmp_input: short ICMP (%"U16_F" bytes) received\n", p->tot_len));
goto lenerr;
}
type = *((u8_t *)p->payload);
#ifdef LWIP_DEBUG
code = *(((u8_t *)p->payload)+1);
#endif /* LWIP_DEBUG */
switch (type) {
case ICMP_ER:
/* This is OK, echo reply might have been parsed by a raw PCB
(as obviously, an echo request has been sent, too). */
MIB2_STATS_INC(mib2.icmpinechoreps);
break;
case ICMP_ECHO:
MIB2_STATS_INC(mib2.icmpinechos);
src = ip4_current_dest_addr();
/* multicast destination address? */
if (ip4_addr_ismulticast(ip4_current_dest_addr())) {
#if LWIP_MULTICAST_PING
/* For multicast, use address of receiving interface as source address */
src = netif_ip4_addr(inp);
#else /* LWIP_MULTICAST_PING */
LWIP_DEBUGF(ICMP_DEBUG, ("icmp_input: Not echoing to multicast pings\n"));
goto icmperr;
#endif /* LWIP_MULTICAST_PING */
}
/* broadcast destination address? */
if (ip4_addr_isbroadcast(ip4_current_dest_addr(), ip_current_netif())) {
#if LWIP_BROADCAST_PING
/* For broadcast, use address of receiving interface as source address */
src = netif_ip4_addr(inp);
#else /* LWIP_BROADCAST_PING */
LWIP_DEBUGF(ICMP_DEBUG, ("icmp_input: Not echoing to broadcast pings\n"));
goto icmperr;
#endif /* LWIP_BROADCAST_PING */
}
LWIP_DEBUGF(ICMP_DEBUG, ("icmp_input: ping\n"));
if (p->tot_len < sizeof(struct icmp_echo_hdr)) {
LWIP_DEBUGF(ICMP_DEBUG, ("icmp_input: bad ICMP echo received\n"));
goto lenerr;
}
#if CHECKSUM_CHECK_ICMP
IF__NETIF_CHECKSUM_ENABLED(inp, NETIF_CHECKSUM_CHECK_ICMP) {
if (inet_chksum_pbuf(p) != 0) {
LWIP_DEBUGF(ICMP_DEBUG, ("icmp_input: checksum failed for received ICMP echo\n"));
pbuf_free(p);
ICMP_STATS_INC(icmp.chkerr);
MIB2_STATS_INC(mib2.icmpinerrors);
return;
}
}
#endif
#if LWIP_ICMP_ECHO_CHECK_INPUT_PBUF_LEN
if (pbuf_header(p, (hlen + PBUF_LINK_HLEN + PBUF_LINK_ENCAPSULATION_HLEN))) {
/* p is not big enough to contain link headers
* allocate a new one and copy p into it
*/
struct pbuf *r;
/* allocate new packet buffer with space for link headers */
r = pbuf_alloc(PBUF_LINK, p->tot_len + hlen, PBUF_RAM);
if (r == NULL) {
LWIP_DEBUGF(ICMP_DEBUG, ("icmp_input: allocating new pbuf failed\n"));
goto icmperr;
}
if (r->len < hlen + sizeof(struct icmp_echo_hdr)) {
LWIP_DEBUGF(ICMP_DEBUG | LWIP_DBG_LEVEL_SERIOUS, ("first pbuf cannot hold the ICMP header"));
pbuf_free(r);
goto icmperr;
}
/* copy the ip header */
MEMCPY(r->payload, iphdr_in, hlen);
/* switch r->payload back to icmp header (cannot fail) */
if (pbuf_header(r, -hlen)) {
LWIP_ASSERT("icmp_input: moving r->payload to icmp header failed\n", 0);
pbuf_free(r);
goto icmperr;
}
/* copy the rest of the packet without ip header */
if (pbuf_copy(r, p) != ERR_OK) {
LWIP_DEBUGF(ICMP_DEBUG | LWIP_DBG_LEVEL_SERIOUS, ("icmp_input: copying to new pbuf failed"));
pbuf_free(r);
goto icmperr;
}
/* free the original p */
pbuf_free(p);
/* we now have an identical copy of p that has room for link headers */
p = r;
} else {
/* restore p->payload to point to icmp header (cannot fail) */
if (pbuf_header(p, -(s16_t)(hlen + PBUF_LINK_HLEN + PBUF_LINK_ENCAPSULATION_HLEN))) {
LWIP_ASSERT("icmp_input: restoring original p->payload failed\n", 0);
goto icmperr;
}
}
#endif /* LWIP_ICMP_ECHO_CHECK_INPUT_PBUF_LEN */
/* At this point, all checks are OK. */
/* We generate an answer by switching the dest and src ip addresses,
* setting the icmp type to ECHO_RESPONSE and updating the checksum. */
iecho = (struct icmp_echo_hdr *)p->payload;
if (pbuf_header(p, hlen)) {
LWIP_DEBUGF(ICMP_DEBUG | LWIP_DBG_LEVEL_SERIOUS, ("Can't move over header in packet"));
} else {
err_t ret;
struct ip_hdr *iphdr = (struct ip_hdr*)p->payload;
ip4_addr_copy(iphdr->src, *src);
ip4_addr_copy(iphdr->dest, *ip4_current_src_addr());
ICMPH_TYPE_SET(iecho, ICMP_ER);
#if CHECKSUM_GEN_ICMP
IF__NETIF_CHECKSUM_ENABLED(inp, NETIF_CHECKSUM_GEN_ICMP) {
/* adjust the checksum */
if (iecho->chksum > PP_HTONS(0xffffU - (ICMP_ECHO << 8))) {
iecho->chksum += PP_HTONS(ICMP_ECHO << 8) + 1;
} else {
iecho->chksum += PP_HTONS(ICMP_ECHO << 8);
}
}
#if LWIP_CHECKSUM_CTRL_PER_NETIF
else {
iecho->chksum = 0;
}
#endif /* LWIP_CHECKSUM_CTRL_PER_NETIF */
#else /* CHECKSUM_GEN_ICMP */
iecho->chksum = 0;
#endif /* CHECKSUM_GEN_ICMP */
/* Set the correct TTL and recalculate the header checksum. */
IPH_TTL_SET(iphdr, ICMP_TTL);
IPH_CHKSUM_SET(iphdr, 0);
#if CHECKSUM_GEN_IP
IF__NETIF_CHECKSUM_ENABLED(inp, NETIF_CHECKSUM_GEN_IP) {
IPH_CHKSUM_SET(iphdr, inet_chksum(iphdr, hlen));
}
#endif /* CHECKSUM_GEN_IP */
ICMP_STATS_INC(icmp.xmit);
/* increase number of messages attempted to send */
MIB2_STATS_INC(mib2.icmpoutmsgs);
/* increase number of echo replies attempted to send */
MIB2_STATS_INC(mib2.icmpoutechoreps);
/* send an ICMP packet */
ret = ip4_output_if(p, src, IP_HDRINCL,
ICMP_TTL, 0, IP_PROTO_ICMP, inp);
if (ret != ERR_OK) {
LWIP_DEBUGF(ICMP_DEBUG, ("icmp_input: ip_output_if returned an error: %s\n", lwip_strerr(ret)));
}
}