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flycast/core/deps/picotcp/modules/pico_arp.c

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/*********************************************************************
PicoTCP. Copyright (c) 2012-2017 Altran Intelligent Systems. Some rights reserved.
See COPYING, LICENSE.GPLv2 and LICENSE.GPLv3 for usage.
.
Authors: Daniele Lacamera
*********************************************************************/
#include "pico_config.h"
#include "pico_arp.h"
#include "pico_tree.h"
#include "pico_ipv4.h"
#include "pico_device.h"
#include "pico_stack.h"
#include "pico_ethernet.h"
extern const uint8_t PICO_ETHADDR_ALL[6];
#define PICO_ARP_TIMEOUT 600000llu
#define PICO_ARP_RETRY 300lu
#define PICO_ARP_MAX_PENDING 5
#ifdef DEBUG_ARP
#define arp_dbg dbg
#else
#define arp_dbg(...) do {} while(0)
#endif
static int max_arp_reqs = PICO_ARP_MAX_RATE;
static struct pico_frame *frames_queued[PICO_ARP_MAX_PENDING] = {
0
};
static void pico_arp_queued_trigger(void)
{
int i;
struct pico_frame *f;
for (i = 0; i < PICO_ARP_MAX_PENDING; i++)
{
f = frames_queued[i];
if (f) {
if (pico_datalink_send(f) <= 0)
pico_frame_discard(f);
frames_queued[i] = NULL;
}
}
}
static void update_max_arp_reqs(pico_time now, void *unused)
{
IGNORE_PARAMETER(now);
IGNORE_PARAMETER(unused);
if (max_arp_reqs < PICO_ARP_MAX_RATE)
max_arp_reqs++;
if (!pico_timer_add(PICO_ARP_INTERVAL / PICO_ARP_MAX_RATE, &update_max_arp_reqs, NULL)) {
arp_dbg("ARP: Failed to start update_max_arps timer\n");
/* TODO if this fails all incoming arps will be discarded once max_arp_reqs recahes 0 */
}
}
void pico_arp_init(void)
{
if (!pico_timer_add(PICO_ARP_INTERVAL / PICO_ARP_MAX_RATE, &update_max_arp_reqs, NULL)) {
arp_dbg("ARP: Failed to start update_max_arps timer\n");
}
}
PACKED_STRUCT_DEF pico_arp_hdr
{
uint16_t htype;
uint16_t ptype;
uint8_t hsize;
uint8_t psize;
uint16_t opcode;
uint8_t s_mac[PICO_SIZE_ETH];
struct pico_ip4 src;
uint8_t d_mac[PICO_SIZE_ETH];
struct pico_ip4 dst;
};
/* Callback handler for ip conflict service (e.g. IPv4 SLAAC)
* Whenever the IP address registered here is seen in the network,
* the callback is awaken to take countermeasures against IP collisions.
*
*/
struct arp_service_ipconflict {
struct pico_eth mac;
struct pico_ip4 ip;
void (*conflict)(int);
};
static struct arp_service_ipconflict conflict_ipv4;
#define PICO_SIZE_ARPHDR ((sizeof(struct pico_arp_hdr)))
/* Arp Entries for the tables. */
struct pico_arp {
/* CAREFUL MAN! ARP entry MUST begin with a pico_eth structure,
* due to in-place casting!!! */
struct pico_eth eth;
struct pico_ip4 ipv4;
int arp_status;
pico_time timestamp;
struct pico_device *dev;
uint32_t timer;
};
/*****************/
/** ARP TREE **/
/*****************/
/* Routing destination */
static int arp_compare(void *ka, void *kb)
{
struct pico_arp *a = ka, *b = kb;
return pico_ipv4_compare(&a->ipv4, &b->ipv4);
}
static PICO_TREE_DECLARE(arp_tree, arp_compare);
/*********************/
/** END ARP TREE **/
/*********************/
struct pico_eth *pico_arp_lookup(struct pico_ip4 *dst)
{
struct pico_arp search, *found;
search.ipv4.addr = dst->addr;
found = pico_tree_findKey(&arp_tree, &search);
if (found && (found->arp_status != PICO_ARP_STATUS_STALE))
return &found->eth;
return NULL;
}
struct pico_ip4 *pico_arp_reverse_lookup(struct pico_eth *dst)
{
struct pico_arp*search;
struct pico_tree_node *index;
pico_tree_foreach(index, &arp_tree){
search = index->keyValue;
if(memcmp(&(search->eth.addr), &dst->addr, 6) == 0)
return &search->ipv4;
}
return NULL;
}
static void pico_arp_unreachable(struct pico_ip4 *a)
{
int i;
struct pico_frame *f;
struct pico_ipv4_hdr *hdr;
struct pico_ip4 dst;
for (i = 0; i < PICO_ARP_MAX_PENDING; i++)
{
f = frames_queued[i];
if (f) {
hdr = (struct pico_ipv4_hdr *) f->net_hdr;
dst = pico_ipv4_route_get_gateway(&hdr->dst);
if (!dst.addr)
dst.addr = hdr->dst.addr;
if (dst.addr == a->addr) {
if (!pico_source_is_local(f)) {
pico_notify_dest_unreachable(f);
}
}
}
}
}
static void pico_arp_retry(struct pico_frame *f, struct pico_ip4 *where)
{
if (++f->failure_count < 4) {
arp_dbg ("================= ARP REQUIRED: %d =============\n\n", f->failure_count);
/* check if dst is local (gateway = 0), or if to use gateway */
pico_arp_request(f->dev, where, PICO_ARP_QUERY);
} else {
pico_arp_unreachable(where);
}
}
struct pico_eth *pico_arp_get(struct pico_frame *f)
{
struct pico_eth *a4;
struct pico_ip4 gateway;
struct pico_ip4 *where;
struct pico_ipv4_hdr *hdr = (struct pico_ipv4_hdr *) f->net_hdr;
struct pico_ipv4_link *l;
if (!hdr)
return NULL;
l = pico_ipv4_link_get(&hdr->dst);
if(l) {
/* address belongs to ourself */
return &l->dev->eth->mac;
}
gateway = pico_ipv4_route_get_gateway(&hdr->dst);
/* check if dst is local (gateway = 0), or if to use gateway */
if (gateway.addr != 0)
where = &gateway;
else
where = &hdr->dst;
a4 = pico_arp_lookup(where); /* check if dst ip mac in cache */
if (!a4)
pico_arp_retry(f, where);
return a4;
}
void pico_arp_postpone(struct pico_frame *f)
{
int i;
for (i = 0; i < PICO_ARP_MAX_PENDING; i++)
{
if (!frames_queued[i]) {
if (f->failure_count < 4)
frames_queued[i] = f;
return;
}
}
/* Not possible to enqueue: caller will discard packet */
}
#ifdef DEBUG_ARP
static void dbg_arp(void)
{
struct pico_arp *a;
struct pico_tree_node *index;
pico_tree_foreach(index, &arp_tree) {
a = index->keyValue;
arp_dbg("ARP to %08x, mac: %02x:%02x:%02x:%02x:%02x:%02x\n", a->ipv4.addr, a->eth.addr[0], a->eth.addr[1], a->eth.addr[2], a->eth.addr[3], a->eth.addr[4], a->eth.addr[5] );
}
}
#endif
static void arp_expire(pico_time now, void *_stale)
{
struct pico_arp *stale = (struct pico_arp *) _stale;
if (now >= (stale->timestamp + PICO_ARP_TIMEOUT)) {
stale->arp_status = PICO_ARP_STATUS_STALE;
arp_dbg("ARP: Setting arp_status to STALE\n");
pico_arp_request(stale->dev, &stale->ipv4, PICO_ARP_QUERY);
} else {
/* Timer must be rescheduled, ARP entry has been renewed lately.
* No action required to refresh the entry, will check on the next timeout */
if (!pico_timer_add(PICO_ARP_TIMEOUT + stale->timestamp - now, arp_expire, stale)) {
arp_dbg("ARP: Failed to start expiration timer, destroying arp entry\n");
pico_tree_delete(&arp_tree, stale);
PICO_FREE(stale);
}
}
}
static int pico_arp_add_entry(struct pico_arp *entry)
{
entry->arp_status = PICO_ARP_STATUS_REACHABLE;
entry->timestamp = PICO_TIME();
if (pico_tree_insert(&arp_tree, entry)) {
arp_dbg("ARP: Failed to insert new entry in tree\n");
return -1;
}
arp_dbg("ARP ## reachable.\n");
pico_arp_queued_trigger();
if (!pico_timer_add(PICO_ARP_TIMEOUT, arp_expire, entry)) {
arp_dbg("ARP: Failed to start expiration timer\n");
pico_tree_delete(&arp_tree, entry);
return -1;
}
return 0;
}
int pico_arp_create_entry(uint8_t *hwaddr, struct pico_ip4 ipv4, struct pico_device *dev)
{
struct pico_arp*arp = PICO_ZALLOC(sizeof(struct pico_arp));
if(!arp) {
pico_err = PICO_ERR_ENOMEM;
return -1;
}
memcpy(arp->eth.addr, hwaddr, 6);
arp->ipv4.addr = ipv4.addr;
arp->dev = dev;
if (pico_arp_add_entry(arp) < 0) {
PICO_FREE(arp);
return -1;
}
return 0;
}
static void pico_arp_check_conflict(struct pico_arp_hdr *hdr)
{
if (conflict_ipv4.conflict)
{
if((conflict_ipv4.ip.addr == hdr->src.addr) &&
(memcmp(hdr->s_mac, conflict_ipv4.mac.addr, PICO_SIZE_ETH) != 0))
conflict_ipv4.conflict(PICO_ARP_CONFLICT_REASON_CONFLICT );
if((hdr->src.addr == 0) && (hdr->dst.addr == conflict_ipv4.ip.addr))
conflict_ipv4.conflict(PICO_ARP_CONFLICT_REASON_PROBE );
}
}
static struct pico_arp *pico_arp_lookup_entry(struct pico_frame *f)
{
struct pico_arp search;
struct pico_arp *found = NULL;
struct pico_arp_hdr *hdr = (struct pico_arp_hdr *) f->net_hdr;
/* Populate a new arp entry */
search.ipv4.addr = hdr->src.addr;
/* Search for already existing entry */
found = pico_tree_findKey(&arp_tree, &search);
if (found) {
if (found->arp_status == PICO_ARP_STATUS_STALE) {
/* Replace if stale */
pico_tree_delete(&arp_tree, found);
if (pico_arp_add_entry(found) < 0) {
arp_dbg("ARP: Failed to re-instert stale arp entry\n");
PICO_FREE(found);
found = NULL;
}
} else {
/* Update mac address */
memcpy(found->eth.addr, hdr->s_mac, PICO_SIZE_ETH);
arp_dbg("ARP entry updated!\n");
/* Refresh timestamp, this will force a reschedule on the next timeout*/
found->timestamp = PICO_TIME();
}
}
return found;
}
static int pico_arp_check_incoming_hdr_type(struct pico_arp_hdr *h)
{
/* Check the hardware type and protocol */
if ((h->htype != PICO_ARP_HTYPE_ETH) || (h->ptype != PICO_IDETH_IPV4))
return -1;
return 0;
}
static int pico_arp_check_incoming_hdr(struct pico_frame *f, struct pico_ip4 *dst_addr)
{
struct pico_arp_hdr *hdr = (struct pico_arp_hdr *) f->net_hdr;
if (!hdr)
return -1;
dst_addr->addr = hdr->dst.addr;
if (pico_arp_check_incoming_hdr_type(hdr) < 0)
return -1;
/* The source mac address must not be a multicast or broadcast address */
if (hdr->s_mac[0] & 0x01)
return -1;
return 0;
}
static void pico_arp_reply_on_request(struct pico_frame *f, struct pico_ip4 me)
{
struct pico_arp_hdr *hdr;
struct pico_eth_hdr *eh;
hdr = (struct pico_arp_hdr *) f->net_hdr;
eh = (struct pico_eth_hdr *)f->datalink_hdr;
if (hdr->opcode != PICO_ARP_REQUEST)
return;
hdr->opcode = PICO_ARP_REPLY;
memcpy(hdr->d_mac, hdr->s_mac, PICO_SIZE_ETH);
memcpy(hdr->s_mac, f->dev->eth->mac.addr, PICO_SIZE_ETH);
hdr->dst.addr = hdr->src.addr;
hdr->src.addr = me.addr;
/* Prepare eth header for arp reply */
memcpy(eh->daddr, eh->saddr, PICO_SIZE_ETH);
memcpy(eh->saddr, f->dev->eth->mac.addr, PICO_SIZE_ETH);
f->start = f->datalink_hdr;
f->len = PICO_SIZE_ETHHDR + PICO_SIZE_ARPHDR;
f->dev->send(f->dev, f->start, (int)f->len);
}
static int pico_arp_check_flooding(struct pico_frame *f, struct pico_ip4 me)
{
struct pico_device *link_dev;
struct pico_arp_hdr *hdr;
hdr = (struct pico_arp_hdr *) f->net_hdr;
/* Prevent ARP flooding */
link_dev = pico_ipv4_link_find(&me);
if ((link_dev == f->dev) && (hdr->opcode == PICO_ARP_REQUEST)) {
if (max_arp_reqs == 0)
return -1;
else
max_arp_reqs--;
}
/* Check if we are the target IP address */
if (link_dev != f->dev)
return -1;
return 0;
}
static int pico_arp_process_in(struct pico_frame *f, struct pico_arp_hdr *hdr, struct pico_arp *found)
{
struct pico_ip4 me;
if (pico_arp_check_incoming_hdr(f, &me) < 0) {
pico_frame_discard(f);
return -1;
}
// FIXME Problem with proxy ARP
// if (pico_arp_check_flooding(f, me) < 0) {
// pico_frame_discard(f);
// return -1;
// }
/* If no existing entry was found, create a new entry, or fail trying. */
/* Do not create an entry for Slaac V4 probe packets (0.0.0.0) */
if ((!found) && (hdr->src.addr == 0 || pico_arp_create_entry(hdr->s_mac, hdr->src, f->dev) < 0)) {
pico_frame_discard(f);
return -1;
}
/* If the packet is a request, send a reply */
pico_arp_reply_on_request(f, me);
#ifdef DEBUG_ARP
dbg_arp();
#endif
pico_frame_discard(f);
return 0;
}
int pico_arp_receive(struct pico_frame *f)
{
struct pico_arp_hdr *hdr;
struct pico_arp *found = NULL;
hdr = (struct pico_arp_hdr *) f->net_hdr;
if (!hdr) {
pico_frame_discard(f);
return -1;
}
pico_arp_check_conflict(hdr);
found = pico_arp_lookup_entry(f);
return pico_arp_process_in(f, hdr, found);
}
static int32_t pico_arp_request_xmit(struct pico_device *dev, struct pico_frame *f, struct pico_ip4 *src, struct pico_ip4 *dst, uint8_t type)
{
struct pico_arp_hdr *ah = (struct pico_arp_hdr *) (f->start + PICO_SIZE_ETHHDR);
int ret;
/* Fill arp header */
ah->htype = PICO_ARP_HTYPE_ETH;
ah->ptype = PICO_IDETH_IPV4;
ah->hsize = PICO_SIZE_ETH;
ah->psize = PICO_SIZE_IP4;
ah->opcode = PICO_ARP_REQUEST;
memcpy(ah->s_mac, dev->eth->mac.addr, PICO_SIZE_ETH);
switch (type) {
case PICO_ARP_ANNOUNCE:
ah->src.addr = dst->addr;
ah->dst.addr = dst->addr;
break;
case PICO_ARP_PROBE:
ah->src.addr = 0;
ah->dst.addr = dst->addr;
break;
case PICO_ARP_QUERY:
ah->src.addr = src->addr;
ah->dst.addr = dst->addr;
break;
default:
pico_frame_discard(f);
return -1;
}
arp_dbg("Sending arp request.\n");
ret = dev->send(dev, f->start, (int) f->len);
pico_frame_discard(f);
return ret;
}
int32_t pico_arp_request(struct pico_device *dev, struct pico_ip4 *dst, uint8_t type)
{
struct pico_frame *q = pico_frame_alloc(PICO_SIZE_ETHHDR + PICO_SIZE_ARPHDR);
struct pico_eth_hdr *eh;
struct pico_ip4 *src = NULL;
if (!q)
return -1;
if (type == PICO_ARP_QUERY)
{
src = pico_ipv4_source_find(dst);
if (!src) {
pico_frame_discard(q);
return -1;
}
}
arp_dbg("QUERY: %08x\n", dst->addr);
eh = (struct pico_eth_hdr *)q->start;
/* Fill eth header */
memcpy(eh->saddr, dev->eth->mac.addr, PICO_SIZE_ETH);
memcpy(eh->daddr, PICO_ETHADDR_ALL, PICO_SIZE_ETH);
eh->proto = PICO_IDETH_ARP;
return pico_arp_request_xmit(dev, q, src, dst, type);
}
int pico_arp_get_neighbors(struct pico_device *dev, struct pico_ip4 *neighbors, int maxlen)
{
struct pico_arp*search;
struct pico_tree_node *index;
int i = 0;
pico_tree_foreach(index, &arp_tree){
search = index->keyValue;
if (search->dev == dev) {
neighbors[i++].addr = search->ipv4.addr;
if (i >= maxlen)
return i;
}
}
return i;
}
void pico_arp_register_ipconflict(struct pico_ip4 *ip, struct pico_eth *mac, void (*cb)(int reason))
{
conflict_ipv4.conflict = cb;
conflict_ipv4.ip.addr = ip->addr;
if (mac != NULL)
memcpy(conflict_ipv4.mac.addr, mac, 6);
}
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