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RIOT/sys/net/gnrc/network_layer/ipv6/gnrc_ipv6.c
Martine Lenders 6d72cdb595 gnrc_ipv6: copy user flags from old netif headers 
Upper layers might want to utilize the flags (e.g. to tell 6LoWPAN to elide
UDP checksums). This change allows for this by copying non-addressing related
flags to the address resolution generated netif header from the user generated
netif header.
2016-07-26 21:06:36 +02:00

987 lines
32 KiB
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Raw Blame History

/*
* 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/blacklist.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);
/* 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;
}
static void _dispatch_next_header(gnrc_pktsnip_t *current, gnrc_pktsnip_t *pkt,
uint8_t nh, bool interested);
/*
* current pkt
* | |
* v v
* IPv6 <- IPv6_EXT <- IPv6_EXT <- UNDEF
*/
void gnrc_ipv6_demux(kernel_pid_t iface, gnrc_pktsnip_t *current, gnrc_pktsnip_t *pkt, uint8_t nh)
{
bool interested = false;
current->type = gnrc_nettype_from_protnum(nh);
switch (nh) {
#ifdef MODULE_GNRC_ICMPV6
case PROTNUM_ICMPV6:
assert(current == pkt);
interested = true;
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:
interested = true;
break;
#endif
case PROTNUM_IPV6:
assert(current == pkt);
interested = true;
break;
default:
(void)iface;
#ifdef MODULE_GNRC_SIXLOWPAN_IPHC_NHC
/* second statement is true for small 6LoWPAN NHC decompressed frames
* since in this case it looks like
*
* * GNRC_NETTYPE_UNDEF <- pkt
* v
* * GNRC_NETTYPE_UDP <- current
* v
* * GNRC_NETTYPE_EXT
* v
* * GNRC_NETTYPE_IPV6
*/
assert((current == pkt) || (current == pkt->next));
#else
assert(current == pkt);
#endif
break;
}
_dispatch_next_header(current, pkt, nh, interested);
if (!interested) {
return;
}
switch (nh) {
#ifdef MODULE_GNRC_ICMPV6
case PROTNUM_ICMPV6:
DEBUG("ipv6: handle ICMPv6 packet (nh = %u)\n", nh);
gnrc_icmpv6_demux(iface, pkt);
gnrc_pktbuf_release(pkt);
return;
#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 = %u)\n", nh);
gnrc_ipv6_ext_demux(iface, current, pkt, nh);
return;
#endif
case PROTNUM_IPV6:
DEBUG("ipv6: handle encapsulated IPv6 packet (nh = %u)\n", nh);
_decapsulate(pkt);
return;
default:
assert(false);
break;
}
assert(false);
}
/* internal functions */
static void _dispatch_next_header(gnrc_pktsnip_t *current, gnrc_pktsnip_t *pkt,
uint8_t nh, bool interested)
{
#ifdef MODULE_GNRC_IPV6_EXT
const bool should_dispatch_current_type = ((current->type != GNRC_NETTYPE_IPV6_EXT) ||
(current->next->type == GNRC_NETTYPE_IPV6));
#else
const bool should_dispatch_current_type = (current->next->type == GNRC_NETTYPE_IPV6);
#endif
DEBUG("ipv6: forward nh = %u to other threads\n", nh);
/* dispatch IPv6 extension header only once */
if (should_dispatch_current_type) {
bool should_release = (gnrc_netreg_num(GNRC_NETTYPE_IPV6, nh) == 0) &&
(!interested);
if (!should_release) {
gnrc_pktbuf_hold(pkt, 1); /* don't remove from packet buffer in
* next dispatch */
}
if (gnrc_netapi_dispatch_receive(current->type,
GNRC_NETREG_DEMUX_CTX_ALL,
pkt) == 0) {
gnrc_pktbuf_release(pkt);
}
if (should_release) {
return;
}
}
if (interested) {
gnrc_pktbuf_hold(pkt, 1); /* don't remove from packet buffer in
* next dispatch */
}
if (gnrc_netapi_dispatch_receive(GNRC_NETTYPE_IPV6, nh, pkt) == 0) {
gnrc_pktbuf_release(pkt);
}
}
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(msg.content.ptr);
break;
case GNRC_NETAPI_MSG_TYPE_SND:
DEBUG("ipv6: GNRC_NETAPI_MSG_TYPE_SND received\n");
_send(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;
/* XXX reactivate when https://github.com/RIOT-OS/RIOT/issues/5122 is
* solved properly */
/* case GNRC_NDP_MSG_ADDR_TIMEOUT: */
/* DEBUG("ipv6: Router advertisement timer event received\n"); */
/* gnrc_ipv6_netif_remove_addr(KERNEL_PID_UNDEF, */
/* 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(msg.content.ptr);
break;
case GNRC_NDP_MSG_NC_STATE_TIMEOUT:
DEBUG("ipv6: Neigbor cache state timeout received\n");
gnrc_ndp_state_timeout(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(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(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(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(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(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(msg.content.ptr);
break;
/* XXX reactivate when https://github.com/RIOT-OS/RIOT/issues/5122 is
* solved properly */
/* case GNRC_SIXLOWPAN_ND_MSG_AR_TIMEOUT: */
/* DEBUG("ipv6: address registration timeout received\n"); */
/* gnrc_sixlowpan_nd_router_gc_nc(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 = 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_NETSTATS_IPV6
if_entry->stats.tx_success++;
if_entry->stats.tx_bytes += gnrc_pkt_len(pkt->next);
#endif
#ifdef MODULE_GNRC_SIXLOWPAN
if (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);
}
}
static gnrc_pktsnip_t *_create_netif_hdr(uint8_t *dst_l2addr,
uint16_t dst_l2addr_len,
gnrc_pktsnip_t *pkt)
{
gnrc_pktsnip_t *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 NULL;
}
if (pkt->type == GNRC_NETTYPE_NETIF) {
/* remove old netif header, since checking it for correctness would
* cause to much overhead.
* netif header might have been allocated by some higher layer either
* to set a sending interface or some flags. Interface was already
* copied using iface parameter, so we only need to copy the flags
* (minus the broadcast/multicast flags) */
DEBUG("ipv6: copy old interface header flags\n");
gnrc_netif_hdr_t *netif_new = netif->data, *netif_old = pkt->data;
netif_new->flags = netif_old->flags & \
~(GNRC_NETIF_HDR_FLAGS_BROADCAST | GNRC_NETIF_HDR_FLAGS_MULTICAST);
DEBUG("ipv6: removed old interface header\n");
pkt = gnrc_pktbuf_remove_snip(pkt, pkt);
}
/* add netif to front of the pkt list */
LL_PREPEND(pkt, netif);
return 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)
{
DEBUG("ipv6: add interface header to packet\n");
if ((pkt = _create_netif_hdr(dst_l2addr, dst_l2addr_len, pkt)) == NULL) {
return;
}
DEBUG("ipv6: send unicast over interface %" PRIkernel_pid "\n", iface);
/* and send to interface */
#ifdef MODULE_NETSTATS_IPV6
gnrc_ipv6_netif_get_stats(iface)->tx_unicast_count++;
#endif
_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 %u (network byteorder %04" PRIx16 ")\n",
(unsigned) 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 %u\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, false);
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;
#ifdef MODULE_NETSTATS_IPV6
gnrc_ipv6_netif_get_stats(iface)->tx_mcast_count++;
#endif
/* 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
/* interface not given: send over all interfaces */
if (iface == KERNEL_PID_UNDEF) {
/* send packet to link layer */
gnrc_pktbuf_hold(pkt, ifnum - 1);
for (size_t i = 0; i < ifnum; i++) {
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;
}
}
if ((ipv6 = _create_netif_hdr(NULL, 0, ipv6)) == NULL) {
return;
}
_send_multicast_over_iface(ifs[i], ipv6);
}
}
else {
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) {
iface = ifs[0];
/* allocate interface header */
if ((pkt = _create_netif_hdr(NULL, 0, pkt)) == NULL) {
return;
}
}
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);
found_iface = gnrc_ipv6_nc_get_l2_addr(l2addr, l2addr_len, nc);
#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 ((!ipv6_addr_is_link_local(&hdr->dst)) ||
(*iface == KERNEL_PID_UNDEF)) {
kernel_pid_t if_pid = gnrc_ipv6_netif_find_by_addr(NULL, &hdr->dst);
if (*iface == KERNEL_PID_UNDEF) {
*iface = if_pid; /* Use original interface for reply if
* existent */
}
return (if_pid == KERNEL_PID_UNDEF);
}
else {
return (gnrc_ipv6_netif_find_addr(*iface, &hdr->dst) == NULL);
}
}
static void _receive(gnrc_pktsnip_t *pkt)
{
kernel_pid_t iface = KERNEL_PID_UNDEF;
gnrc_pktsnip_t *ipv6, *netif, *first_ext;
ipv6_hdr_t *hdr;
assert(pkt != NULL);
netif = gnrc_pktsnip_search_type(pkt, GNRC_NETTYPE_NETIF);
if (netif != NULL) {
iface = ((gnrc_netif_hdr_t *)netif->data)->if_pid;
#ifdef MODULE_NETSTATS_IPV6
assert(iface);
netstats_t *stats = gnrc_ipv6_netif_get_stats(iface);
stats->rx_count++;
stats->rx_bytes += (gnrc_pkt_len(pkt) - netif->size);
#endif
}
first_ext = pkt;
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;
}
first_ext = ipv6;
}
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
#ifdef MODULE_GNRC_IPV6_BLACKLIST
if (gnrc_ipv6_blacklisted(&((ipv6_hdr_t *)(pkt->data))->src)) {
DEBUG("ipv6: Source address blacklisted, 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);
first_ext = pkt;
pkt->type = GNRC_NETTYPE_UNDEF; /* snip is no longer 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
#ifdef MODULE_GNRC_IPV6_BLACKLIST
else if (gnrc_ipv6_blacklisted(&((ipv6_hdr_t *)(ipv6->data))->src)) {
/* if ipv6 header already marked*/
DEBUG("ipv6: Source address blacklisted, 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));
}
else if (byteorder_ntohs(hdr->len) >
(gnrc_pkt_len_upto(pkt, GNRC_NETTYPE_IPV6) - sizeof(ipv6_hdr_t))) {
DEBUG("ipv6: invalid payload length: %d, actual: %d, dropping packet\n",
(int) byteorder_ntohs(hdr->len),
(int) (gnrc_pkt_len_upto(pkt, GNRC_NETTYPE_IPV6) - sizeof(ipv6_hdr_t)));
gnrc_pktbuf_release(pkt);
return;
}
DEBUG("ipv6: Received (src = %s, ",
ipv6_addr_to_str(addr_str, &(hdr->src), sizeof(addr_str)));
DEBUG("dst = %s, next header = %u, 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 %u\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;
}
/* remove L2 headers around IPV6 */
netif = gnrc_pktsnip_search_type(pkt, GNRC_NETTYPE_NETIF);
if (netif != NULL) {
gnrc_pktbuf_remove_snip(pkt, netif);
}
/* reverse packet snip list order */
while (ptr != NULL) {
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, first_ext, 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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