zephyr/subsys/net/l2/ethernet/arp.c

1006 lines
25 KiB
C

/** @file
* @brief ARP related functions
*/
/*
* Copyright (c) 2016 Intel Corporation
*
* SPDX-License-Identifier: Apache-2.0
*/
#include <zephyr/logging/log.h>
LOG_MODULE_REGISTER(net_arp, CONFIG_NET_ARP_LOG_LEVEL);
#include <errno.h>
#include <zephyr/net/net_core.h>
#include <zephyr/net/net_pkt.h>
#include <zephyr/net/net_if.h>
#include <zephyr/net/net_stats.h>
#include <zephyr/net/net_mgmt.h>
#include "arp.h"
#include "net_private.h"
#define NET_BUF_TIMEOUT K_MSEC(100)
#define ARP_REQUEST_TIMEOUT (2 * MSEC_PER_SEC)
static bool arp_cache_initialized;
static struct arp_entry arp_entries[CONFIG_NET_ARP_TABLE_SIZE];
static sys_slist_t arp_free_entries;
static sys_slist_t arp_pending_entries;
static sys_slist_t arp_table;
static struct k_work_delayable arp_request_timer;
static struct k_mutex arp_mutex;
#if defined(CONFIG_NET_ARP_GRATUITOUS_TRANSMISSION)
static struct net_mgmt_event_callback iface_event_cb;
static struct net_mgmt_event_callback ipv4_event_cb;
static struct k_work_delayable arp_gratuitous_work;
#endif /* defined(CONFIG_NET_ARP_GRATUITOUS_TRANSMISSION) */
static void arp_entry_cleanup(struct arp_entry *entry, bool pending)
{
NET_DBG("entry %p", entry);
if (pending) {
struct net_pkt *pkt;
while (!k_fifo_is_empty(&entry->pending_queue)) {
pkt = k_fifo_get(&entry->pending_queue, K_FOREVER);
NET_DBG("Releasing pending pkt %p (ref %ld)",
pkt,
atomic_get(&pkt->atomic_ref) - 1);
net_pkt_unref(pkt);
}
}
entry->iface = NULL;
(void)memset(&entry->ip, 0, sizeof(struct in_addr));
(void)memset(&entry->eth, 0, sizeof(struct net_eth_addr));
}
static struct arp_entry *arp_entry_find(sys_slist_t *list,
struct net_if *iface,
struct in_addr *dst,
sys_snode_t **previous)
{
struct arp_entry *entry;
SYS_SLIST_FOR_EACH_CONTAINER(list, entry, node) {
NET_DBG("iface %d (%p) dst %s",
net_if_get_by_iface(iface), iface,
net_sprint_ipv4_addr(&entry->ip));
if (entry->iface == iface &&
net_ipv4_addr_cmp(&entry->ip, dst)) {
return entry;
}
if (previous) {
*previous = &entry->node;
}
}
return NULL;
}
static inline struct arp_entry *arp_entry_find_move_first(struct net_if *iface,
struct in_addr *dst)
{
sys_snode_t *prev = NULL;
struct arp_entry *entry;
NET_DBG("dst %s", net_sprint_ipv4_addr(dst));
entry = arp_entry_find(&arp_table, iface, dst, &prev);
if (entry) {
/* Let's assume the target is going to be accessed
* more than once here in a short time frame. So we
* place the entry first in position into the table
* in order to reduce subsequent find.
*/
if (&entry->node != sys_slist_peek_head(&arp_table)) {
sys_slist_remove(&arp_table, prev, &entry->node);
sys_slist_prepend(&arp_table, &entry->node);
}
}
return entry;
}
static inline
struct arp_entry *arp_entry_find_pending(struct net_if *iface,
struct in_addr *dst)
{
NET_DBG("dst %s", net_sprint_ipv4_addr(dst));
return arp_entry_find(&arp_pending_entries, iface, dst, NULL);
}
static struct arp_entry *arp_entry_get_pending(struct net_if *iface,
struct in_addr *dst)
{
sys_snode_t *prev = NULL;
struct arp_entry *entry;
NET_DBG("dst %s", net_sprint_ipv4_addr(dst));
entry = arp_entry_find(&arp_pending_entries, iface, dst, &prev);
if (entry) {
/* We remove the entry from the pending list */
sys_slist_remove(&arp_pending_entries, prev, &entry->node);
}
if (sys_slist_is_empty(&arp_pending_entries)) {
k_work_cancel_delayable(&arp_request_timer);
}
return entry;
}
static struct arp_entry *arp_entry_get_free(void)
{
sys_snode_t *node;
node = sys_slist_peek_head(&arp_free_entries);
if (!node) {
return NULL;
}
/* We remove the node from the free list */
sys_slist_remove(&arp_free_entries, NULL, node);
return CONTAINER_OF(node, struct arp_entry, node);
}
static struct arp_entry *arp_entry_get_last_from_table(void)
{
sys_snode_t *node;
/* We assume last entry is the oldest one,
* so is the preferred one to be taken out.
*/
node = sys_slist_peek_tail(&arp_table);
if (!node) {
return NULL;
}
sys_slist_find_and_remove(&arp_table, node);
return CONTAINER_OF(node, struct arp_entry, node);
}
static void arp_entry_register_pending(struct arp_entry *entry)
{
NET_DBG("dst %s", net_sprint_ipv4_addr(&entry->ip));
sys_slist_append(&arp_pending_entries, &entry->node);
entry->req_start = k_uptime_get_32();
/* Let's start the timer if necessary */
if (!k_work_delayable_remaining_get(&arp_request_timer)) {
k_work_reschedule(&arp_request_timer,
K_MSEC(ARP_REQUEST_TIMEOUT));
}
}
static void arp_request_timeout(struct k_work *work)
{
uint32_t current = k_uptime_get_32();
struct arp_entry *entry, *next;
ARG_UNUSED(work);
k_mutex_lock(&arp_mutex, K_FOREVER);
SYS_SLIST_FOR_EACH_CONTAINER_SAFE(&arp_pending_entries,
entry, next, node) {
if ((int32_t)(entry->req_start +
ARP_REQUEST_TIMEOUT - current) > 0) {
break;
}
arp_entry_cleanup(entry, true);
sys_slist_remove(&arp_pending_entries, NULL, &entry->node);
sys_slist_append(&arp_free_entries, &entry->node);
entry = NULL;
}
if (entry) {
k_work_reschedule(&arp_request_timer,
K_MSEC(entry->req_start +
ARP_REQUEST_TIMEOUT - current));
}
k_mutex_unlock(&arp_mutex);
}
static inline struct in_addr *if_get_addr(struct net_if *iface,
struct in_addr *addr)
{
struct net_if_ipv4 *ipv4 = iface->config.ip.ipv4;
if (!ipv4) {
return NULL;
}
ARRAY_FOR_EACH(ipv4->unicast, i) {
if (ipv4->unicast[i].ipv4.is_used &&
ipv4->unicast[i].ipv4.address.family == AF_INET &&
ipv4->unicast[i].ipv4.addr_state == NET_ADDR_PREFERRED &&
(!addr ||
net_ipv4_addr_cmp(addr,
&ipv4->unicast[i].ipv4.address.in_addr))) {
return &ipv4->unicast[i].ipv4.address.in_addr;
}
}
return NULL;
}
static inline struct net_pkt *arp_prepare(struct net_if *iface,
struct in_addr *next_addr,
struct arp_entry *entry,
struct net_pkt *pending,
struct in_addr *current_ip)
{
struct net_arp_hdr *hdr;
struct in_addr *my_addr;
struct net_pkt *pkt;
if (current_ip) {
/* This is the IPv4 autoconf case where we have already
* things setup so no need to allocate new net_pkt
*/
pkt = pending;
} else {
pkt = net_pkt_alloc_with_buffer(iface,
sizeof(struct net_arp_hdr),
AF_UNSPEC, 0, NET_BUF_TIMEOUT);
if (!pkt) {
return NULL;
}
/* Avoid recursive loop with network packet capturing */
if (IS_ENABLED(CONFIG_NET_CAPTURE) && pending) {
net_pkt_set_captured(pkt, net_pkt_is_captured(pending));
}
if (IS_ENABLED(CONFIG_NET_VLAN) && pending) {
net_pkt_set_vlan_tag(pkt, net_pkt_vlan_tag(pending));
}
}
net_buf_add(pkt->buffer, sizeof(struct net_arp_hdr));
hdr = NET_ARP_HDR(pkt);
/* If entry is not set, then we are just about to send
* an ARP request using the data in pending net_pkt.
* This can happen if there is already a pending ARP
* request and we want to send it again.
*/
if (entry) {
if (!net_pkt_ipv4_acd(pkt)) {
k_fifo_put(&entry->pending_queue, net_pkt_ref(pending));
}
entry->iface = net_pkt_iface(pkt);
net_ipaddr_copy(&entry->ip, next_addr);
net_pkt_lladdr_src(pkt)->addr =
(uint8_t *)net_if_get_link_addr(entry->iface)->addr;
arp_entry_register_pending(entry);
} else {
net_pkt_lladdr_src(pkt)->addr =
(uint8_t *)net_if_get_link_addr(iface)->addr;
}
net_pkt_lladdr_src(pkt)->len = sizeof(struct net_eth_addr);
net_pkt_lladdr_dst(pkt)->addr = (uint8_t *)net_eth_broadcast_addr();
net_pkt_lladdr_dst(pkt)->len = sizeof(struct net_eth_addr);
hdr->hwtype = htons(NET_ARP_HTYPE_ETH);
hdr->protocol = htons(NET_ETH_PTYPE_IP);
hdr->hwlen = sizeof(struct net_eth_addr);
hdr->protolen = sizeof(struct in_addr);
hdr->opcode = htons(NET_ARP_REQUEST);
(void)memset(&hdr->dst_hwaddr.addr, 0x00, sizeof(struct net_eth_addr));
net_ipv4_addr_copy_raw(hdr->dst_ipaddr, (uint8_t *)next_addr);
memcpy(hdr->src_hwaddr.addr, net_pkt_lladdr_src(pkt)->addr,
sizeof(struct net_eth_addr));
if (net_pkt_ipv4_acd(pkt)) {
my_addr = current_ip;
} else if (!entry) {
my_addr = (struct in_addr *)NET_IPV4_HDR(pending)->src;
} else {
my_addr = if_get_addr(entry->iface, current_ip);
}
if (my_addr) {
net_ipv4_addr_copy_raw(hdr->src_ipaddr, (uint8_t *)my_addr);
} else {
(void)memset(&hdr->src_ipaddr, 0, sizeof(struct in_addr));
}
NET_DBG("Generating request for %s", net_sprint_ipv4_addr(next_addr));
return pkt;
}
struct net_pkt *net_arp_prepare(struct net_pkt *pkt,
struct in_addr *request_ip,
struct in_addr *current_ip)
{
bool is_ipv4_ll_used = false;
struct arp_entry *entry;
struct in_addr *addr;
if (!pkt || !pkt->buffer) {
return NULL;
}
if (net_pkt_ipv4_acd(pkt)) {
return arp_prepare(net_pkt_iface(pkt), request_ip, NULL,
pkt, current_ip);
}
if (IS_ENABLED(CONFIG_NET_IPV4_AUTO)) {
is_ipv4_ll_used = net_ipv4_is_ll_addr((struct in_addr *)
&NET_IPV4_HDR(pkt)->src) ||
net_ipv4_is_ll_addr((struct in_addr *)
&NET_IPV4_HDR(pkt)->dst);
}
/* Is the destination in the local network, if not route via
* the gateway address.
*/
if (!current_ip && !is_ipv4_ll_used &&
!net_if_ipv4_addr_mask_cmp(net_pkt_iface(pkt), request_ip)) {
struct net_if_ipv4 *ipv4 = net_pkt_iface(pkt)->config.ip.ipv4;
if (ipv4) {
addr = &ipv4->gw;
if (net_ipv4_is_addr_unspecified(addr)) {
NET_ERR("Gateway not set for iface %p",
net_pkt_iface(pkt));
return NULL;
}
} else {
addr = request_ip;
}
} else {
addr = request_ip;
}
k_mutex_lock(&arp_mutex, K_FOREVER);
/* If the destination address is already known, we do not need
* to send any ARP packet.
*/
entry = arp_entry_find_move_first(net_pkt_iface(pkt), addr);
if (!entry) {
struct net_pkt *req;
entry = arp_entry_find_pending(net_pkt_iface(pkt), addr);
if (!entry) {
/* No pending, let's try to get a new entry */
entry = arp_entry_get_free();
if (!entry) {
/* Then let's take one from table? */
entry = arp_entry_get_last_from_table();
}
} else {
/* There is a pending ARP request already, check if this packet is already
* in the pending list and if so, resend the request, otherwise just
* append the packet to the request fifo list.
*/
if (k_queue_unique_append(&entry->pending_queue._queue,
net_pkt_ref(pkt))) {
NET_DBG("Pending ARP request for %s, queuing pkt %p",
net_sprint_ipv4_addr(addr), pkt);
k_mutex_unlock(&arp_mutex);
return NULL;
}
entry = NULL;
}
req = arp_prepare(net_pkt_iface(pkt), addr, entry, pkt,
current_ip);
if (!entry) {
/* We cannot send the packet, the ARP cache is full
* or there is already a pending query to this IP
* address, so this packet must be discarded.
*/
NET_DBG("Resending ARP %p", req);
}
if (!req && entry) {
/* Add the arp entry back to arp_free_entries, to avoid the
* arp entry is leak due to ARP packet allocated failed.
*/
sys_slist_prepend(&arp_free_entries, &entry->node);
}
k_mutex_unlock(&arp_mutex);
return req;
}
k_mutex_unlock(&arp_mutex);
net_pkt_lladdr_src(pkt)->addr =
(uint8_t *)net_if_get_link_addr(entry->iface)->addr;
net_pkt_lladdr_src(pkt)->len = sizeof(struct net_eth_addr);
net_pkt_lladdr_dst(pkt)->addr = (uint8_t *)&entry->eth;
net_pkt_lladdr_dst(pkt)->len = sizeof(struct net_eth_addr);
NET_DBG("ARP using ll %s for IP %s",
net_sprint_ll_addr(net_pkt_lladdr_dst(pkt)->addr,
sizeof(struct net_eth_addr)),
net_sprint_ipv4_addr(&NET_IPV4_HDR(pkt)->dst));
return pkt;
}
static void arp_gratuitous(struct net_if *iface,
struct in_addr *src,
struct net_eth_addr *hwaddr)
{
sys_snode_t *prev = NULL;
struct arp_entry *entry;
entry = arp_entry_find(&arp_table, iface, src, &prev);
if (entry) {
NET_DBG("Gratuitous ARP hwaddr %s -> %s",
net_sprint_ll_addr((const uint8_t *)&entry->eth,
sizeof(struct net_eth_addr)),
net_sprint_ll_addr((const uint8_t *)hwaddr,
sizeof(struct net_eth_addr)));
memcpy(&entry->eth, hwaddr, sizeof(struct net_eth_addr));
}
}
#if defined(CONFIG_NET_ARP_GRATUITOUS_TRANSMISSION)
static void arp_gratuitous_send(struct net_if *iface,
struct in_addr *ipaddr)
{
struct net_arp_hdr *hdr;
struct net_pkt *pkt;
pkt = net_pkt_alloc_with_buffer(iface, sizeof(struct net_arp_hdr),
AF_UNSPEC, 0, NET_BUF_TIMEOUT);
if (!pkt) {
return;
}
net_buf_add(pkt->buffer, sizeof(struct net_arp_hdr));
net_pkt_set_vlan_tag(pkt, net_eth_get_vlan_tag(iface));
hdr = NET_ARP_HDR(pkt);
hdr->hwtype = htons(NET_ARP_HTYPE_ETH);
hdr->protocol = htons(NET_ETH_PTYPE_IP);
hdr->hwlen = sizeof(struct net_eth_addr);
hdr->protolen = sizeof(struct in_addr);
hdr->opcode = htons(NET_ARP_REQUEST);
memcpy(&hdr->dst_hwaddr.addr, net_eth_broadcast_addr(),
sizeof(struct net_eth_addr));
memcpy(&hdr->src_hwaddr.addr, net_if_get_link_addr(iface)->addr,
sizeof(struct net_eth_addr));
net_ipv4_addr_copy_raw(hdr->dst_ipaddr, (uint8_t *)ipaddr);
net_ipv4_addr_copy_raw(hdr->src_ipaddr, (uint8_t *)ipaddr);
net_pkt_lladdr_src(pkt)->addr = net_if_get_link_addr(iface)->addr;
net_pkt_lladdr_src(pkt)->len = sizeof(struct net_eth_addr);
net_pkt_lladdr_dst(pkt)->addr = (uint8_t *)net_eth_broadcast_addr();
net_pkt_lladdr_dst(pkt)->len = sizeof(struct net_eth_addr);
NET_DBG("Sending gratuitous ARP pkt %p", pkt);
if (net_if_send_data(iface, pkt) == NET_DROP) {
net_pkt_unref(pkt);
}
}
static void notify_all_ipv4_addr(struct net_if *iface)
{
struct net_if_ipv4 *ipv4 = iface->config.ip.ipv4;
int i;
if (!ipv4) {
return;
}
for (i = 0; i < NET_IF_MAX_IPV4_ADDR; i++) {
if (ipv4->unicast[i].ipv4.is_used &&
ipv4->unicast[i].ipv4.address.family == AF_INET &&
ipv4->unicast[i].ipv4.addr_state == NET_ADDR_PREFERRED) {
arp_gratuitous_send(iface,
&ipv4->unicast[i].ipv4.address.in_addr);
}
}
}
static void iface_event_handler(struct net_mgmt_event_callback *cb,
uint32_t mgmt_event, struct net_if *iface)
{
ARG_UNUSED(cb);
if (!(net_if_l2(iface) == &NET_L2_GET_NAME(ETHERNET) ||
net_eth_is_vlan_interface(iface))) {
return;
}
if (mgmt_event != NET_EVENT_IF_UP) {
return;
}
notify_all_ipv4_addr(iface);
}
static void ipv4_event_handler(struct net_mgmt_event_callback *cb,
uint32_t mgmt_event, struct net_if *iface)
{
struct in_addr *ipaddr;
if (!(net_if_l2(iface) == &NET_L2_GET_NAME(ETHERNET) ||
net_eth_is_vlan_interface(iface))) {
return;
}
if (!net_if_is_up(iface)) {
return;
}
if (mgmt_event != NET_EVENT_IPV4_ADDR_ADD) {
return;
}
if (cb->info_length != sizeof(struct in_addr)) {
return;
}
ipaddr = (struct in_addr *)cb->info;
arp_gratuitous_send(iface, ipaddr);
}
static void iface_cb(struct net_if *iface, void *user_data)
{
ARG_UNUSED(user_data);
if (!(net_if_l2(iface) == &NET_L2_GET_NAME(ETHERNET) ||
net_eth_is_vlan_interface(iface))) {
return;
}
if (!net_if_is_up(iface)) {
return;
}
notify_all_ipv4_addr(iface);
}
static void arp_gratuitous_work_handler(struct k_work *work)
{
ARG_UNUSED(work);
net_if_foreach(iface_cb, NULL);
k_work_reschedule(&arp_gratuitous_work,
K_SECONDS(CONFIG_NET_ARP_GRATUITOUS_INTERVAL));
}
#endif /* defined(CONFIG_NET_ARP_GRATUITOUS_TRANSMISSION) */
void net_arp_update(struct net_if *iface,
struct in_addr *src,
struct net_eth_addr *hwaddr,
bool gratuitous,
bool force)
{
struct arp_entry *entry;
struct net_pkt *pkt;
NET_DBG("iface %d (%p) src %s", net_if_get_by_iface(iface), iface,
net_sprint_ipv4_addr(src));
net_if_tx_lock(iface);
k_mutex_lock(&arp_mutex, K_FOREVER);
entry = arp_entry_get_pending(iface, src);
if (!entry) {
if (IS_ENABLED(CONFIG_NET_ARP_GRATUITOUS) && gratuitous) {
arp_gratuitous(iface, src, hwaddr);
}
if (force) {
sys_snode_t *prev = NULL;
struct arp_entry *arp_ent;
arp_ent = arp_entry_find(&arp_table, iface, src, &prev);
if (arp_ent) {
memcpy(&arp_ent->eth, hwaddr,
sizeof(struct net_eth_addr));
} else {
/* Add new entry as it was not found and force
* was set.
*/
arp_ent = arp_entry_get_free();
if (!arp_ent) {
/* Then let's take one from table? */
arp_ent = arp_entry_get_last_from_table();
}
if (arp_ent) {
arp_ent->req_start = k_uptime_get_32();
arp_ent->iface = iface;
net_ipaddr_copy(&arp_ent->ip, src);
memcpy(&arp_ent->eth, hwaddr, sizeof(arp_ent->eth));
sys_slist_prepend(&arp_table, &arp_ent->node);
}
}
}
k_mutex_unlock(&arp_mutex);
net_if_tx_unlock(iface);
return;
}
memcpy(&entry->eth, hwaddr, sizeof(struct net_eth_addr));
/* Inserting entry into the table */
sys_slist_prepend(&arp_table, &entry->node);
while (!k_fifo_is_empty(&entry->pending_queue)) {
int ret;
pkt = k_fifo_get(&entry->pending_queue, K_FOREVER);
/* Set the dst in the pending packet */
net_pkt_lladdr_dst(pkt)->len = sizeof(struct net_eth_addr);
net_pkt_lladdr_dst(pkt)->addr =
(uint8_t *) &NET_ETH_HDR(pkt)->dst.addr;
NET_DBG("iface %d (%p) dst %s pending %p frag %p",
net_if_get_by_iface(iface), iface,
net_sprint_ipv4_addr(&entry->ip),
pkt, pkt->frags);
/* We directly send the packet without first queueing it.
* The pkt has already been queued for sending, once by
* net_if and second time in the ARP queue. We must not
* queue it twice in net_if so that the statistics of
* the pkt are not counted twice and the packet filter
* callbacks are only called once.
*/
ret = net_if_l2(iface)->send(iface, pkt);
if (ret < 0) {
net_pkt_unref(pkt);
}
}
k_mutex_unlock(&arp_mutex);
net_if_tx_unlock(iface);
}
static inline struct net_pkt *arp_prepare_reply(struct net_if *iface,
struct net_pkt *req,
struct net_eth_hdr *eth_query,
struct net_eth_addr *dst_addr)
{
struct net_arp_hdr *hdr, *query;
struct net_pkt *pkt;
pkt = net_pkt_alloc_with_buffer(iface, sizeof(struct net_arp_hdr),
AF_UNSPEC, 0, NET_BUF_TIMEOUT);
if (!pkt) {
return NULL;
}
net_buf_add(pkt->buffer, sizeof(struct net_arp_hdr));
hdr = NET_ARP_HDR(pkt);
query = NET_ARP_HDR(req);
if (IS_ENABLED(CONFIG_NET_VLAN)) {
net_pkt_set_vlan_tag(pkt, net_pkt_vlan_tag(req));
}
hdr->hwtype = htons(NET_ARP_HTYPE_ETH);
hdr->protocol = htons(NET_ETH_PTYPE_IP);
hdr->hwlen = sizeof(struct net_eth_addr);
hdr->protolen = sizeof(struct in_addr);
hdr->opcode = htons(NET_ARP_REPLY);
memcpy(&hdr->dst_hwaddr.addr, &dst_addr->addr,
sizeof(struct net_eth_addr));
memcpy(&hdr->src_hwaddr.addr, net_if_get_link_addr(iface)->addr,
sizeof(struct net_eth_addr));
net_ipv4_addr_copy_raw(hdr->dst_ipaddr, query->src_ipaddr);
net_ipv4_addr_copy_raw(hdr->src_ipaddr, query->dst_ipaddr);
net_pkt_lladdr_src(pkt)->addr = net_if_get_link_addr(iface)->addr;
net_pkt_lladdr_src(pkt)->len = sizeof(struct net_eth_addr);
net_pkt_lladdr_dst(pkt)->addr = (uint8_t *)&hdr->dst_hwaddr.addr;
net_pkt_lladdr_dst(pkt)->len = sizeof(struct net_eth_addr);
return pkt;
}
static bool arp_hdr_check(struct net_arp_hdr *arp_hdr)
{
if (ntohs(arp_hdr->hwtype) != NET_ARP_HTYPE_ETH ||
ntohs(arp_hdr->protocol) != NET_ETH_PTYPE_IP ||
arp_hdr->hwlen != sizeof(struct net_eth_addr) ||
arp_hdr->protolen != NET_ARP_IPV4_PTYPE_SIZE ||
net_ipv4_is_addr_loopback((struct in_addr *)arp_hdr->src_ipaddr)) {
NET_DBG("DROP: Invalid ARP header");
return false;
}
return true;
}
enum net_verdict net_arp_input(struct net_pkt *pkt,
struct net_eth_hdr *eth_hdr)
{
struct net_eth_addr *dst_hw_addr;
struct net_arp_hdr *arp_hdr;
struct net_pkt *reply;
struct in_addr *addr;
if (net_pkt_get_len(pkt) < (sizeof(struct net_arp_hdr) -
(net_pkt_ip_data(pkt) - (uint8_t *)eth_hdr))) {
NET_DBG("Invalid ARP header (len %zu, min %zu bytes) %p",
net_pkt_get_len(pkt), sizeof(struct net_arp_hdr) -
(net_pkt_ip_data(pkt) - (uint8_t *)eth_hdr), pkt);
return NET_DROP;
}
arp_hdr = NET_ARP_HDR(pkt);
if (!arp_hdr_check(arp_hdr)) {
return NET_DROP;
}
switch (ntohs(arp_hdr->opcode)) {
case NET_ARP_REQUEST:
/* If ARP request sender hw address is our address,
* we must drop the packet.
*/
if (memcmp(&arp_hdr->src_hwaddr,
net_if_get_link_addr(net_pkt_iface(pkt))->addr,
sizeof(struct net_eth_addr)) == 0) {
return NET_DROP;
}
if (IS_ENABLED(CONFIG_NET_ARP_GRATUITOUS)) {
if (net_eth_is_addr_broadcast(&eth_hdr->dst) &&
(net_eth_is_addr_broadcast(&arp_hdr->dst_hwaddr) ||
net_eth_is_addr_all_zeroes(&arp_hdr->dst_hwaddr)) &&
net_ipv4_addr_cmp_raw(arp_hdr->dst_ipaddr,
arp_hdr->src_ipaddr)) {
/* If the IP address is in our cache,
* then update it here.
*/
net_arp_update(net_pkt_iface(pkt),
(struct in_addr *)arp_hdr->src_ipaddr,
&arp_hdr->src_hwaddr,
true, false);
break;
}
}
/* Discard ARP request if Ethernet address is broadcast
* and Source IP address is Multicast address.
*/
if (memcmp(&eth_hdr->dst, net_eth_broadcast_addr(),
sizeof(struct net_eth_addr)) == 0 &&
net_ipv4_is_addr_mcast((struct in_addr *)arp_hdr->src_ipaddr)) {
NET_DBG("DROP: eth addr is bcast, src addr is mcast");
return NET_DROP;
}
/* Someone wants to know our ll address */
addr = if_get_addr(net_pkt_iface(pkt),
(struct in_addr *)arp_hdr->dst_ipaddr);
if (!addr) {
/* Not for us so drop the packet silently */
return NET_DROP;
}
NET_DBG("ARP request from %s [%s] for %s",
net_sprint_ipv4_addr(&arp_hdr->src_ipaddr),
net_sprint_ll_addr((uint8_t *)&arp_hdr->src_hwaddr,
arp_hdr->hwlen),
net_sprint_ipv4_addr(&arp_hdr->dst_ipaddr));
/* Update the ARP cache if the sender MAC address has
* changed. In this case the target MAC address is all zeros
* and the target IP address is our address.
*/
if (net_eth_is_addr_unspecified(&arp_hdr->dst_hwaddr)) {
NET_DBG("Updating ARP cache for %s [%s] iface %d",
net_sprint_ipv4_addr(&arp_hdr->src_ipaddr),
net_sprint_ll_addr((uint8_t *)&arp_hdr->src_hwaddr,
arp_hdr->hwlen),
net_if_get_by_iface(net_pkt_iface(pkt)));
net_arp_update(net_pkt_iface(pkt),
(struct in_addr *)arp_hdr->src_ipaddr,
&arp_hdr->src_hwaddr,
false, true);
dst_hw_addr = &arp_hdr->src_hwaddr;
} else {
dst_hw_addr = &eth_hdr->src;
}
/* Send reply */
reply = arp_prepare_reply(net_pkt_iface(pkt), pkt, eth_hdr,
dst_hw_addr);
if (reply) {
net_if_queue_tx(net_pkt_iface(reply), reply);
} else {
NET_DBG("Cannot send ARP reply");
}
break;
case NET_ARP_REPLY:
if (net_ipv4_is_my_addr((struct in_addr *)arp_hdr->dst_ipaddr)) {
NET_DBG("Received ll %s for IP %s",
net_sprint_ll_addr(arp_hdr->src_hwaddr.addr,
sizeof(struct net_eth_addr)),
net_sprint_ipv4_addr(arp_hdr->src_ipaddr));
net_arp_update(net_pkt_iface(pkt),
(struct in_addr *)arp_hdr->src_ipaddr,
&arp_hdr->src_hwaddr,
false, false);
}
break;
}
net_pkt_unref(pkt);
return NET_OK;
}
void net_arp_clear_cache(struct net_if *iface)
{
sys_snode_t *prev = NULL;
struct arp_entry *entry, *next;
NET_DBG("Flushing ARP table");
k_mutex_lock(&arp_mutex, K_FOREVER);
SYS_SLIST_FOR_EACH_CONTAINER_SAFE(&arp_table, entry, next, node) {
if (iface && iface != entry->iface) {
prev = &entry->node;
continue;
}
arp_entry_cleanup(entry, false);
sys_slist_remove(&arp_table, prev, &entry->node);
sys_slist_prepend(&arp_free_entries, &entry->node);
}
prev = NULL;
NET_DBG("Flushing ARP pending requests");
SYS_SLIST_FOR_EACH_CONTAINER_SAFE(&arp_pending_entries,
entry, next, node) {
if (iface && iface != entry->iface) {
prev = &entry->node;
continue;
}
arp_entry_cleanup(entry, true);
sys_slist_remove(&arp_pending_entries, prev, &entry->node);
sys_slist_prepend(&arp_free_entries, &entry->node);
}
if (sys_slist_is_empty(&arp_pending_entries)) {
k_work_cancel_delayable(&arp_request_timer);
}
k_mutex_unlock(&arp_mutex);
}
int net_arp_clear_pending(struct net_if *iface, struct in_addr *dst)
{
struct arp_entry *entry = arp_entry_find_pending(iface, dst);
if (!entry) {
return -ENOENT;
}
arp_entry_cleanup(entry, true);
return 0;
}
int net_arp_foreach(net_arp_cb_t cb, void *user_data)
{
int ret = 0;
struct arp_entry *entry;
k_mutex_lock(&arp_mutex, K_FOREVER);
SYS_SLIST_FOR_EACH_CONTAINER(&arp_table, entry, node) {
ret++;
cb(entry, user_data);
}
k_mutex_unlock(&arp_mutex);
return ret;
}
void net_arp_init(void)
{
int i;
if (arp_cache_initialized) {
return;
}
sys_slist_init(&arp_free_entries);
sys_slist_init(&arp_pending_entries);
sys_slist_init(&arp_table);
for (i = 0; i < CONFIG_NET_ARP_TABLE_SIZE; i++) {
/* Inserting entry as free with initialised packet queue */
k_fifo_init(&arp_entries[i].pending_queue);
sys_slist_prepend(&arp_free_entries, &arp_entries[i].node);
}
k_work_init_delayable(&arp_request_timer, arp_request_timeout);
k_mutex_init(&arp_mutex);
arp_cache_initialized = true;
#if defined(CONFIG_NET_ARP_GRATUITOUS_TRANSMISSION)
net_mgmt_init_event_callback(&iface_event_cb, iface_event_handler,
NET_EVENT_IF_UP);
net_mgmt_init_event_callback(&ipv4_event_cb, ipv4_event_handler,
NET_EVENT_IPV4_ADDR_ADD);
net_mgmt_add_event_callback(&iface_event_cb);
net_mgmt_add_event_callback(&ipv4_event_cb);
k_work_init_delayable(&arp_gratuitous_work,
arp_gratuitous_work_handler);
k_work_reschedule(&arp_gratuitous_work,
K_SECONDS(CONFIG_NET_ARP_GRATUITOUS_INTERVAL));
#endif /* defined(CONFIG_NET_ARP_GRATUITOUS_TRANSMISSION) */
}