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RIOT/sys/net/gnrc/network_layer/ipv6/gnrc_ipv6.c

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/*
* Copyright (C) 2015 Martine Lenders <mlenders@inf.fu-berlin.de>
*
* This file is subject to the terms and conditions of the GNU Lesser
* General Public License v2.1. See the file LICENSE in the top level
* directory for more details.
*/
/**
* @{
*
* @file
*/
#include <assert.h>
#include <errno.h>
#include <inttypes.h>
#include <stdbool.h>
#include "byteorder.h"
#include "cpu_conf.h"
#include "kernel_types.h"
#include "net/gnrc.h"
#include "net/gnrc/icmpv6.h"
#include "net/gnrc/ndp.h"
#include "net/gnrc/sixlowpan/ctx.h"
#include "net/gnrc/sixlowpan/nd.h"
#include "net/gnrc/sixlowpan/nd/router.h"
#include "net/protnum.h"
#include "thread.h"
#include "utlist.h"
#include "net/gnrc/ipv6/nc.h"
#include "net/gnrc/ipv6/netif.h"
#include "net/gnrc/ipv6/whitelist.h"
#include "net/gnrc/ipv6.h"
#define ENABLE_DEBUG (0)
#include "debug.h"
#define _MAX_L2_ADDR_LEN (8U)
#if ENABLE_DEBUG
static char _stack[GNRC_IPV6_STACK_SIZE + THREAD_EXTRA_STACKSIZE_PRINTF];
#else
static char _stack[GNRC_IPV6_STACK_SIZE];
#endif
#ifdef MODULE_FIB
#include "net/fib.h"
#include "net/fib/table.h"
/**
* @brief buffer to store the entries in the IPv6 forwarding table
*/
static fib_entry_t _fib_entries[GNRC_IPV6_FIB_TABLE_SIZE];
/**
* @brief the IPv6 forwarding table
*/
fib_table_t gnrc_ipv6_fib_table;
#endif
#if ENABLE_DEBUG
static char addr_str[IPV6_ADDR_MAX_STR_LEN];
#endif
kernel_pid_t gnrc_ipv6_pid = KERNEL_PID_UNDEF;
/* handles GNRC_NETAPI_MSG_TYPE_RCV commands */
static void _receive(gnrc_pktsnip_t *pkt);
/* dispatches received IPv6 packet for upper layer */
static void _dispatch_rcv_pkt(gnrc_nettype_t type, uint32_t demux_ctx,
gnrc_pktsnip_t *pkt);
/* Sends packet over the appropriate interface(s).
* prep_hdr: prepare header for sending (call to _fill_ipv6_hdr()), otherwise
* assume it is already prepared */
static void _send(gnrc_pktsnip_t *pkt, bool prep_hdr);
/* Main event loop for IPv6 */
static void *_event_loop(void *args);
/* Handles encapsulated IPv6 packets: http://tools.ietf.org/html/rfc2473 */
static void _decapsulate(gnrc_pktsnip_t *pkt);
kernel_pid_t gnrc_ipv6_init(void)
{
if (gnrc_ipv6_pid == KERNEL_PID_UNDEF) {
gnrc_ipv6_pid = thread_create(_stack, sizeof(_stack), GNRC_IPV6_PRIO,
THREAD_CREATE_STACKTEST,
_event_loop, NULL, "ipv6");
}
#ifdef MODULE_FIB
gnrc_ipv6_fib_table.data.entries = _fib_entries;
gnrc_ipv6_fib_table.table_type = FIB_TABLE_TYPE_SH;
gnrc_ipv6_fib_table.size = GNRC_IPV6_FIB_TABLE_SIZE;
fib_init(&gnrc_ipv6_fib_table);
#endif
return gnrc_ipv6_pid;
}
void gnrc_ipv6_demux(kernel_pid_t iface, gnrc_pktsnip_t *pkt, uint8_t nh)
{
int receiver_num;
pkt->type = gnrc_nettype_from_protnum(nh);
switch (nh) {
#ifdef MODULE_GNRC_ICMPV6
case PROTNUM_ICMPV6:
DEBUG("ipv6: handle ICMPv6 packet (nh = %" PRIu8 ")\n", nh);
gnrc_icmpv6_demux(iface, pkt);
break;
#endif
#ifdef MODULE_GNRC_IPV6_EXT
case PROTNUM_IPV6_EXT_HOPOPT:
case PROTNUM_IPV6_EXT_DST:
case PROTNUM_IPV6_EXT_RH:
case PROTNUM_IPV6_EXT_FRAG:
case PROTNUM_IPV6_EXT_AH:
case PROTNUM_IPV6_EXT_ESP:
case PROTNUM_IPV6_EXT_MOB:
DEBUG("ipv6: handle extension header (nh = %" PRIu8 ")\n", nh);
if (!gnrc_ipv6_ext_demux(iface, pkt, nh)) {
DEBUG("ipv6: unable to parse extension headers.\n");
gnrc_pktbuf_release(pkt);
return;
}
#endif
case PROTNUM_IPV6:
DEBUG("ipv6: handle encapsulated IPv6 packet (nh = %" PRIu8 ")\n", nh);
_decapsulate(pkt);
break;
default:
(void)iface;
break;
}
DEBUG("ipv6: forward nh = %" PRIu8 " to other threads\n", nh);
receiver_num = gnrc_netreg_num(pkt->type, GNRC_NETREG_DEMUX_CTX_ALL) +
gnrc_netreg_num(GNRC_NETTYPE_IPV6, nh);
if (receiver_num == 0) {
DEBUG("ipv6: unable to forward packet as no one is interested in it\n");
gnrc_pktbuf_release(pkt);
return;
}
gnrc_pktbuf_hold(pkt, receiver_num - 1); /* IPv6 is not interested anymore so `- 1` */
/* XXX can't use gnrc_netapi_dispatch_receive() twice here since a call to that function
* implicitly hands all rights to the packet to one of the receiving threads. As a result,
* the second call to gnrc_netapi_dispatch_receive() would be invalid */
_dispatch_rcv_pkt(pkt->type, GNRC_NETREG_DEMUX_CTX_ALL, pkt);
_dispatch_rcv_pkt(GNRC_NETTYPE_IPV6, nh, pkt);
}
/* internal functions */
static void *_event_loop(void *args)
{
msg_t msg, reply, msg_q[GNRC_IPV6_MSG_QUEUE_SIZE];
gnrc_netreg_entry_t me_reg;
(void)args;
msg_init_queue(msg_q, GNRC_IPV6_MSG_QUEUE_SIZE);
me_reg.demux_ctx = GNRC_NETREG_DEMUX_CTX_ALL;
me_reg.pid = thread_getpid();
/* register interest in all IPv6 packets */
gnrc_netreg_register(GNRC_NETTYPE_IPV6, &me_reg);
/* preinitialize ACK */
reply.type = GNRC_NETAPI_MSG_TYPE_ACK;
/* start event loop */
while (1) {
DEBUG("ipv6: waiting for incoming message.\n");
msg_receive(&msg);
switch (msg.type) {
case GNRC_NETAPI_MSG_TYPE_RCV:
DEBUG("ipv6: GNRC_NETAPI_MSG_TYPE_RCV received\n");
_receive((gnrc_pktsnip_t *)msg.content.ptr);
break;
case GNRC_NETAPI_MSG_TYPE_SND:
DEBUG("ipv6: GNRC_NETAPI_MSG_TYPE_SND received\n");
_send((gnrc_pktsnip_t *)msg.content.ptr, true);
break;
case GNRC_NETAPI_MSG_TYPE_GET:
case GNRC_NETAPI_MSG_TYPE_SET:
DEBUG("ipv6: reply to unsupported get/set\n");
reply.content.value = -ENOTSUP;
msg_reply(&msg, &reply);
break;
#ifdef MODULE_GNRC_NDP
case GNRC_NDP_MSG_RTR_TIMEOUT:
DEBUG("ipv6: Router timeout received\n");
((gnrc_ipv6_nc_t *)msg.content.ptr)->flags &= ~GNRC_IPV6_NC_IS_ROUTER;
break;
case GNRC_NDP_MSG_ADDR_TIMEOUT:
DEBUG("ipv6: Router advertisement timer event received\n");
gnrc_ipv6_netif_remove_addr(KERNEL_PID_UNDEF,
(ipv6_addr_t *)msg.content.ptr);
break;
case GNRC_NDP_MSG_NBR_SOL_RETRANS:
DEBUG("ipv6: Neigbor solicitation retransmission timer event received\n");
gnrc_ndp_retrans_nbr_sol((gnrc_ipv6_nc_t *)msg.content.ptr);
break;
case GNRC_NDP_MSG_NC_STATE_TIMEOUT:
DEBUG("ipv6: Neigbor cache state timeout received\n");
gnrc_ndp_state_timeout((gnrc_ipv6_nc_t *)msg.content.ptr);
break;
#endif
#ifdef MODULE_GNRC_NDP_ROUTER
case GNRC_NDP_MSG_RTR_ADV_RETRANS:
DEBUG("ipv6: Router advertisement retransmission event received\n");
gnrc_ndp_router_retrans_rtr_adv((gnrc_ipv6_netif_t *)msg.content.ptr);
break;
case GNRC_NDP_MSG_RTR_ADV_DELAY:
DEBUG("ipv6: Delayed router advertisement event received\n");
gnrc_ndp_router_send_rtr_adv((gnrc_ipv6_nc_t *)msg.content.ptr);
break;
#endif
#ifdef MODULE_GNRC_NDP_HOST
case GNRC_NDP_MSG_RTR_SOL_RETRANS:
DEBUG("ipv6: Router solicitation retransmission event received\n");
gnrc_ndp_host_retrans_rtr_sol((gnrc_ipv6_netif_t *)msg.content.ptr);
break;
#endif
#ifdef MODULE_GNRC_SIXLOWPAN_ND
case GNRC_SIXLOWPAN_ND_MSG_MC_RTR_SOL:
DEBUG("ipv6: Multicast router solicitation event received\n");
gnrc_sixlowpan_nd_mc_rtr_sol((gnrc_ipv6_netif_t *)msg.content.ptr);
break;
case GNRC_SIXLOWPAN_ND_MSG_UC_RTR_SOL:
DEBUG("ipv6: Unicast router solicitation event received\n");
gnrc_sixlowpan_nd_uc_rtr_sol((gnrc_ipv6_nc_t *)msg.content.ptr);
break;
# ifdef MODULE_GNRC_SIXLOWPAN_CTX
case GNRC_SIXLOWPAN_ND_MSG_DELETE_CTX:
DEBUG("ipv6: Delete 6LoWPAN context event received\n");
gnrc_sixlowpan_ctx_remove(((((gnrc_sixlowpan_ctx_t *)msg.content.ptr)->flags_id) &
GNRC_SIXLOWPAN_CTX_FLAGS_CID_MASK));
break;
# endif
#endif
#ifdef MODULE_GNRC_SIXLOWPAN_ND_ROUTER
case GNRC_SIXLOWPAN_ND_MSG_ABR_TIMEOUT:
DEBUG("ipv6: border router timeout event received\n");
gnrc_sixlowpan_nd_router_abr_remove(
(gnrc_sixlowpan_nd_router_abr_t *)msg.content.ptr);
break;
case GNRC_SIXLOWPAN_ND_MSG_AR_TIMEOUT:
DEBUG("ipv6: address registration timeout received\n");
gnrc_sixlowpan_nd_router_gc_nc((gnrc_ipv6_nc_t *)msg.content.ptr);
break;
case GNRC_NDP_MSG_RTR_ADV_SIXLOWPAN_DELAY:
DEBUG("ipv6: Delayed router advertisement event received\n");
gnrc_ipv6_nc_t *nc_entry = (gnrc_ipv6_nc_t *)msg.content.ptr;
gnrc_ndp_internal_send_rtr_adv(nc_entry->iface, NULL,
&(nc_entry->ipv6_addr), false);
break;
#endif
default:
break;
}
}
return NULL;
}
static void _send_to_iface(kernel_pid_t iface, gnrc_pktsnip_t *pkt)
{
((gnrc_netif_hdr_t *)pkt->data)->if_pid = iface;
gnrc_ipv6_netif_t *if_entry = gnrc_ipv6_netif_get(iface);
assert(if_entry != NULL);
if (gnrc_pkt_len(pkt->next) > if_entry->mtu) {
DEBUG("ipv6: packet too big\n");
gnrc_pktbuf_release(pkt);
return;
}
#ifdef MODULE_GNRC_SIXLOWPAN
if ((if_entry != NULL) && (if_entry->flags & GNRC_IPV6_NETIF_FLAGS_SIXLOWPAN)) {
DEBUG("ipv6: send to 6LoWPAN instead\n");
if (!gnrc_netapi_dispatch_send(GNRC_NETTYPE_SIXLOWPAN, GNRC_NETREG_DEMUX_CTX_ALL, pkt)) {
DEBUG("ipv6: no 6LoWPAN thread found");
gnrc_pktbuf_release(pkt);
}
return;
}
#endif
if (gnrc_netapi_send(iface, pkt) < 1) {
DEBUG("ipv6: unable to send packet\n");
gnrc_pktbuf_release(pkt);
}
}
/* functions for sending */
static void _send_unicast(kernel_pid_t iface, uint8_t *dst_l2addr,
uint16_t dst_l2addr_len, gnrc_pktsnip_t *pkt)
{
gnrc_pktsnip_t *netif;
if (pkt->type == GNRC_NETTYPE_NETIF) {
/* great: someone already added a netif_hdr_t we assume it's wrong
* to keep it simple
* XXX: alternative would be to check if gnrc_netif_hdr_t::dst_l2addr_len
* is long enough and only then to throw away the header. This causes
* to much overhead IMHO */
DEBUG("ipv6: removed old interface header\n");
pkt = gnrc_pktbuf_remove_snip(pkt, pkt);
}
DEBUG("ipv6: add interface header to packet\n");
netif = gnrc_netif_hdr_build(NULL, 0, dst_l2addr, dst_l2addr_len);
if (netif == NULL) {
DEBUG("ipv6: error on interface header allocation, dropping packet\n");
gnrc_pktbuf_release(pkt);
return;
}
/* add netif to front of the pkt list */
LL_PREPEND(pkt, netif);
DEBUG("ipv6: send unicast over interface %" PRIkernel_pid "\n", iface);
/* and send to interface */
_send_to_iface(iface, pkt);
}
static int _fill_ipv6_hdr(kernel_pid_t iface, gnrc_pktsnip_t *ipv6,
gnrc_pktsnip_t *payload)
{
int res;
ipv6_hdr_t *hdr = ipv6->data;
hdr->len = byteorder_htons(gnrc_pkt_len(payload));
DEBUG("ipv6: set payload length to %zu (network byteorder %04" PRIx16 ")\n",
gnrc_pkt_len(payload), hdr->len.u16);
/* check if e.g. extension header was not already marked */
if (hdr->nh == PROTNUM_RESERVED) {
hdr->nh = gnrc_nettype_to_protnum(payload->type);
/* if still reserved: mark no next header */
if (hdr->nh == PROTNUM_RESERVED) {
hdr->nh = PROTNUM_IPV6_NONXT;
}
}
DEBUG("ipv6: set next header to %" PRIu8 "\n", hdr->nh);
if (hdr->hl == 0) {
if (iface == KERNEL_PID_UNDEF) {
hdr->hl = GNRC_IPV6_NETIF_DEFAULT_HL;
}
else {
hdr->hl = gnrc_ipv6_netif_get(iface)->cur_hl;
}
}
if (ipv6_addr_is_unspecified(&hdr->src)) {
if (ipv6_addr_is_loopback(&hdr->dst)) {
ipv6_addr_set_loopback(&hdr->src);
}
else {
ipv6_addr_t *src = gnrc_ipv6_netif_find_best_src_addr(iface, &hdr->dst);
if (src != NULL) {
DEBUG("ipv6: set packet source to %s\n",
ipv6_addr_to_str(addr_str, src, sizeof(addr_str)));
memcpy(&hdr->src, src, sizeof(ipv6_addr_t));
}
/* Otherwise leave unspecified */
}
}
DEBUG("ipv6: calculate checksum for upper header.\n");
if ((res = gnrc_netreg_calc_csum(payload, ipv6)) < 0) {
if (res != -ENOENT) { /* if there is no checksum we are okay */
DEBUG("ipv6: checksum calculation failed.\n");
return res;
}
}
return 0;
}
static inline void _send_multicast_over_iface(kernel_pid_t iface, gnrc_pktsnip_t *pkt)
{
DEBUG("ipv6: send multicast over interface %" PRIkernel_pid "\n", iface);
/* mark as multicast */
((gnrc_netif_hdr_t *)pkt->data)->flags |= GNRC_NETIF_HDR_FLAGS_MULTICAST;
/* and send to interface */
_send_to_iface(iface, pkt);
}
static void _send_multicast(kernel_pid_t iface, gnrc_pktsnip_t *pkt,
gnrc_pktsnip_t *ipv6, gnrc_pktsnip_t *payload,
bool prep_hdr)
{
kernel_pid_t ifs[GNRC_NETIF_NUMOF];
size_t ifnum = 0;
if (iface == KERNEL_PID_UNDEF) {
/* get list of interfaces */
ifnum = gnrc_netif_get(ifs);
/* throw away packet if no one is interested */
if (ifnum == 0) {
DEBUG("ipv6: no interfaces registered, dropping packet\n");
gnrc_pktbuf_release(pkt);
return;
}
}
#if GNRC_NETIF_NUMOF > 1
/* netif header not present: send over all interfaces */
if (iface == KERNEL_PID_UNDEF) {
assert(pkt == ipv6);
/* send packet to link layer */
gnrc_pktbuf_hold(pkt, ifnum - 1);
for (size_t i = 0; i < ifnum; i++) {
gnrc_pktsnip_t *netif;
if (prep_hdr) {
/* need to get second write access (duplication) to fill IPv6
* header interface-local */
gnrc_pktsnip_t *tmp = gnrc_pktbuf_start_write(pkt);
gnrc_pktsnip_t *ptr = tmp->next;
ipv6 = tmp;
if (ipv6 == NULL) {
DEBUG("ipv6: unable to get write access to IPv6 header, "
"for interface %" PRIkernel_pid "\n", ifs[i]);
gnrc_pktbuf_release(pkt);
return;
}
/* multiple interfaces => possibly different source addresses
* => different checksums => duplication of payload needed */
while (ptr != payload->next) {
/* duplicate everything including payload */
tmp->next = gnrc_pktbuf_start_write(ptr);
if (tmp->next == NULL) {
DEBUG("ipv6: unable to get write access to payload, drop it\n");
gnrc_pktbuf_release(ipv6);
return;
}
tmp = tmp->next;
ptr = ptr->next;
}
if (_fill_ipv6_hdr(ifs[i], ipv6, tmp) < 0) {
/* error on filling up header */
gnrc_pktbuf_release(ipv6);
return;
}
}
/* allocate interface header */
netif = gnrc_netif_hdr_build(NULL, 0, NULL, 0);
if (netif == NULL) {
DEBUG("ipv6: error on interface header allocation, "
"dropping packet\n");
gnrc_pktbuf_release(ipv6);
return;
}
LL_PREPEND(ipv6, netif);
_send_multicast_over_iface(ifs[i], ipv6);
}
}
else {
/* iface != KERNEL_PID_UNDEF implies that netif header is present */
assert(pkt != ipv6);
if (prep_hdr) {
if (_fill_ipv6_hdr(iface, ipv6, payload) < 0) {
/* error on filling up header */
gnrc_pktbuf_release(pkt);
return;
}
}
_send_multicast_over_iface(iface, pkt);
}
#else /* GNRC_NETIF_NUMOF */
(void)ifnum; /* not used in this build branch */
if (iface == KERNEL_PID_UNDEF) {
gnrc_pktsnip_t *netif;
iface = ifs[0];
/* allocate interface header */
netif = gnrc_netif_hdr_build(NULL, 0, NULL, 0);
if (netif == NULL) {
DEBUG("ipv6: error on interface header allocation, "
"dropping packet\n");
gnrc_pktbuf_release(pkt);
return;
}
LL_PREPEND(pkt, netif);
}
if (prep_hdr) {
if (_fill_ipv6_hdr(iface, ipv6, payload) < 0) {
/* error on filling up header */
gnrc_pktbuf_release(pkt);
return;
}
}
_send_multicast_over_iface(iface, pkt);
#endif /* GNRC_NETIF_NUMOF */
}
static inline kernel_pid_t _next_hop_l2addr(uint8_t *l2addr, uint8_t *l2addr_len,
kernel_pid_t iface, ipv6_addr_t *dst,
gnrc_pktsnip_t *pkt)
{
kernel_pid_t found_iface;
#if defined(MODULE_GNRC_SIXLOWPAN_ND)
(void)pkt;
found_iface = gnrc_sixlowpan_nd_next_hop_l2addr(l2addr, l2addr_len, iface, dst);
if (found_iface > KERNEL_PID_UNDEF) {
return found_iface;
}
#endif
#if defined(MODULE_GNRC_NDP_NODE)
found_iface = gnrc_ndp_node_next_hop_l2addr(l2addr, l2addr_len, iface, dst, pkt);
#elif !defined(MODULE_GNRC_SIXLOWPAN_ND) && defined(MODULE_GNRC_IPV6_NC)
(void)pkt;
gnrc_ipv6_nc_t *nc = gnrc_ipv6_nc_get(iface, dst);
if ((nc == NULL) || !gnrc_ipv6_nc_is_reachable(nc)) {
return KERNEL_PID_UNDEF;
}
found_iface = nc->iface;
*l2addr_len = nc->l2_addr_len;
memcpy(l2addr, nc->l2_addr, nc->l2_addr_len);
#elif !defined(MODULE_GNRC_SIXLOWPAN_ND)
found_iface = KERNEL_PID_UNDEF;
(void)l2addr;
(void)l2addr_len;
(void)iface;
(void)dst;
(void)pkt;
*l2addr_len = 0;
#endif
return found_iface;
}
static void _send(gnrc_pktsnip_t *pkt, bool prep_hdr)
{
kernel_pid_t iface = KERNEL_PID_UNDEF;
gnrc_pktsnip_t *ipv6, *payload;
ipv6_addr_t *tmp;
ipv6_hdr_t *hdr;
/* get IPv6 snip and (if present) generic interface header */
if (pkt->type == GNRC_NETTYPE_NETIF) {
/* If there is already a netif header (routing protocols and
* neighbor discovery might add them to preset sending interface) */
iface = ((gnrc_netif_hdr_t *)pkt->data)->if_pid;
/* seize payload as temporary variable */
ipv6 = gnrc_pktbuf_start_write(pkt); /* write protect for later removal
* in _send_unicast() */
if (ipv6 == NULL) {
DEBUG("ipv6: unable to get write access to netif header, dropping packet\n");
gnrc_pktbuf_release(pkt);
return;
}
pkt = ipv6; /* Reset pkt from temporary variable */
ipv6 = pkt->next;
}
else {
ipv6 = pkt;
}
/* seize payload as temporary variable */
payload = gnrc_pktbuf_start_write(ipv6);
if (payload == NULL) {
DEBUG("ipv6: unable to get write access to IPv6 header, dropping packet\n");
gnrc_pktbuf_release(pkt);
return;
}
if (ipv6 != pkt) { /* in case packet has netif header */
pkt->next = payload;/* pkt is already write-protected so we can do that */
}
else {
pkt = payload; /* pkt is the IPv6 header so we just write-protected it */
}
ipv6 = payload; /* Reset ipv6 from temporary variable */
hdr = ipv6->data;
payload = ipv6->next;
if (ipv6_addr_is_multicast(&hdr->dst)) {
_send_multicast(iface, pkt, ipv6, payload, prep_hdr);
}
else if ((ipv6_addr_is_loopback(&hdr->dst)) || /* dst is loopback address */
((iface == KERNEL_PID_UNDEF) && /* or dst registered to any local interface */
((iface = gnrc_ipv6_netif_find_by_addr(&tmp, &hdr->dst)) != KERNEL_PID_UNDEF)) ||
((iface != KERNEL_PID_UNDEF) && /* or dst registered to given interface */
(gnrc_ipv6_netif_find_addr(iface, &hdr->dst) != NULL))) {
uint8_t *rcv_data;
gnrc_pktsnip_t *ptr = ipv6, *rcv_pkt;
if (prep_hdr) {
if (_fill_ipv6_hdr(iface, ipv6, payload) < 0) {
/* error on filling up header */
gnrc_pktbuf_release(pkt);
return;
}
}
rcv_pkt = gnrc_pktbuf_add(NULL, NULL, gnrc_pkt_len(ipv6), GNRC_NETTYPE_IPV6);
if (rcv_pkt == NULL) {
DEBUG("ipv6: error on generating loopback packet\n");
gnrc_pktbuf_release(pkt);
return;
}
rcv_data = rcv_pkt->data;
/* "reverse" packet (by making it one snip as if received from NIC) */
while (ptr != NULL) {
memcpy(rcv_data, ptr->data, ptr->size);
rcv_data += ptr->size;
ptr = ptr->next;
}
gnrc_pktbuf_release(pkt);
DEBUG("ipv6: packet is addressed to myself => loopback\n");
if (gnrc_netapi_receive(gnrc_ipv6_pid, rcv_pkt) < 1) {
DEBUG("ipv6: unable to deliver packet\n");
gnrc_pktbuf_release(rcv_pkt);
}
}
else {
uint8_t l2addr_len = GNRC_IPV6_NC_L2_ADDR_MAX;
uint8_t l2addr[l2addr_len];
iface = _next_hop_l2addr(l2addr, &l2addr_len, iface, &hdr->dst, pkt);
if (iface == KERNEL_PID_UNDEF) {
DEBUG("ipv6: error determining next hop's link layer address\n");
gnrc_pktbuf_release(pkt);
return;
}
if (prep_hdr) {
if (_fill_ipv6_hdr(iface, ipv6, payload) < 0) {
/* error on filling up header */
gnrc_pktbuf_release(pkt);
return;
}
}
_send_unicast(iface, l2addr, l2addr_len, pkt);
}
}
/* functions for receiving */
static inline bool _pkt_not_for_me(kernel_pid_t *iface, ipv6_hdr_t *hdr)
{
if (ipv6_addr_is_loopback(&hdr->dst)) {
return false;
}
else if (*iface == KERNEL_PID_UNDEF) {
*iface = gnrc_ipv6_netif_find_by_addr(NULL, &hdr->dst);
return (*iface == KERNEL_PID_UNDEF);
}
else {
return (gnrc_ipv6_netif_find_addr(*iface, &hdr->dst) == NULL);
}
}
static void _dispatch_rcv_pkt(gnrc_nettype_t type, uint32_t demux_ctx,
gnrc_pktsnip_t *pkt)
{
gnrc_netreg_entry_t *entry = gnrc_netreg_lookup(type, demux_ctx);
while (entry) {
DEBUG("ipv6: Send receive command for %p to %" PRIu16 "\n", (void *)pkt,
entry->pid);
if (gnrc_netapi_receive(entry->pid, pkt) < 1) {
DEBUG("ipv6: unable to deliver packet\n");
gnrc_pktbuf_release(pkt);
}
entry = gnrc_netreg_getnext(entry);
}
}
static void _receive(gnrc_pktsnip_t *pkt)
{
kernel_pid_t iface = KERNEL_PID_UNDEF;
gnrc_pktsnip_t *ipv6, *netif;
ipv6_hdr_t *hdr;
assert(pkt != NULL);
LL_SEARCH_SCALAR(pkt, netif, type, GNRC_NETTYPE_NETIF);
if (netif != NULL) {
iface = ((gnrc_netif_hdr_t *)netif->data)->if_pid;
}
for (ipv6 = pkt; ipv6 != NULL; ipv6 = ipv6->next) { /* find IPv6 header if already marked */
if ((ipv6->type == GNRC_NETTYPE_IPV6) && (ipv6->size == sizeof(ipv6_hdr_t)) &&
(ipv6_hdr_is(ipv6->data))) {
break;
}
}
if (ipv6 == NULL) {
if (!ipv6_hdr_is(pkt->data)) {
DEBUG("ipv6: Received packet was not IPv6, dropping packet\n");
gnrc_pktbuf_release(pkt);
return;
}
#ifdef MODULE_GNRC_IPV6_WHITELIST
if (!gnrc_ipv6_whitelisted(&((ipv6_hdr_t *)(pkt->data))->src)) {
DEBUG("ipv6: Source address not whitelisted, dropping packet\n");
gnrc_pktbuf_release(pkt);
return;
}
#endif
/* seize ipv6 as a temporary variable */
ipv6 = gnrc_pktbuf_start_write(pkt);
if (ipv6 == NULL) {
DEBUG("ipv6: unable to get write access to packet, drop it\n");
gnrc_pktbuf_release(pkt);
return;
}
pkt = ipv6; /* reset pkt from temporary variable */
ipv6 = gnrc_pktbuf_mark(pkt, sizeof(ipv6_hdr_t), GNRC_NETTYPE_IPV6);
if (ipv6 == NULL) {
DEBUG("ipv6: error marking IPv6 header, dropping packet\n");
gnrc_pktbuf_release(pkt);
return;
}
}
#ifdef MODULE_GNRC_IPV6_WHITELIST
else if (!gnrc_ipv6_whitelisted(&((ipv6_hdr_t *)(ipv6->data))->src)) {
/* if ipv6 header already marked*/
DEBUG("ipv6: Source address not whitelisted, dropping packet\n");
gnrc_pktbuf_release(pkt);
return;
}
#endif
/* extract header */
hdr = (ipv6_hdr_t *)ipv6->data;
/* if available, remove any padding that was added by lower layers
* to fulfill their minimum size requirements (e.g. ethernet) */
if (byteorder_ntohs(hdr->len) < pkt->size) {
gnrc_pktbuf_realloc_data(pkt, byteorder_ntohs(hdr->len));
}
DEBUG("ipv6: Received (src = %s, ",
ipv6_addr_to_str(addr_str, &(hdr->src), sizeof(addr_str)));
DEBUG("dst = %s, next header = %" PRIu8 ", length = %" PRIu16 ")\n",
ipv6_addr_to_str(addr_str, &(hdr->dst), sizeof(addr_str)),
hdr->nh, byteorder_ntohs(hdr->len));
if (_pkt_not_for_me(&iface, hdr)) { /* if packet is not for me */
DEBUG("ipv6: packet destination not this host\n");
#ifdef MODULE_GNRC_IPV6_ROUTER /* only routers redirect */
/* redirect to next hop */
DEBUG("ipv6: decrement hop limit to %" PRIu8 "\n", (uint8_t) (hdr->hl - 1));
/* RFC 4291, section 2.5.6 states: "Routers must not forward any
* packets with Link-Local source or destination addresses to other
* links."
*/
if ((ipv6_addr_is_link_local(&(hdr->src))) || (ipv6_addr_is_link_local(&(hdr->dst)))) {
DEBUG("ipv6: do not forward packets with link-local source or"\
" destination address\n");
gnrc_pktbuf_release(pkt);
return;
}
/* TODO: check if receiving interface is router */
else if (--(hdr->hl) > 0) { /* drop packets that *reach* Hop Limit 0 */
gnrc_pktsnip_t *reversed_pkt = NULL, *ptr = pkt;
DEBUG("ipv6: forward packet to next hop\n");
/* pkt might not be writable yet, if header was given above */
ipv6 = gnrc_pktbuf_start_write(ipv6);
if (ipv6 == NULL) {
DEBUG("ipv6: unable to get write access to packet: dropping it\n");
gnrc_pktbuf_release(pkt);
return;
}
gnrc_pktbuf_remove_snip(pkt, ipv6->next); /* remove L2 headers around IPV6 */
while (ptr != NULL) { /* reverse packet order */
gnrc_pktsnip_t *next;
ptr = gnrc_pktbuf_start_write(ptr); /* duplicate if not already done */
if (ptr == NULL) {
DEBUG("ipv6: unable to get write access to packet: dropping it\n");
gnrc_pktbuf_release(reversed_pkt);
gnrc_pktbuf_release(pkt);
return;
}
next = ptr->next;
ptr->next = reversed_pkt;
reversed_pkt = ptr;
ptr = next;
}
_send(reversed_pkt, false);
return;
}
else {
DEBUG("ipv6: hop limit reached 0: drop packet\n");
gnrc_pktbuf_release(pkt);
return;
}
#else /* MODULE_GNRC_IPV6_ROUTER */
DEBUG("ipv6: dropping packet\n");
/* non rounting hosts just drop the packet */
gnrc_pktbuf_release(pkt);
return;
#endif /* MODULE_GNRC_IPV6_ROUTER */
}
/* IPv6 internal demuxing (ICMPv6, Extension headers etc.) */
gnrc_ipv6_demux(iface, pkt, hdr->nh);
}
static void _decapsulate(gnrc_pktsnip_t *pkt)
{
gnrc_pktsnip_t *ptr = pkt;
pkt->type = GNRC_NETTYPE_UNDEF; /* prevent payload (the encapsulated packet)
* from being removed */
/* Remove encapsulating IPv6 header */
while ((ptr->next != NULL) && (ptr->next->type == GNRC_NETTYPE_IPV6)) {
gnrc_pktbuf_remove_snip(pkt, pkt->next);
}
pkt->type = GNRC_NETTYPE_IPV6;
_receive(pkt);
}
/** @} */
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