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RIOT/sys/net/network_layer/ng_ipv6/ng_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 <errno.h>
#include <inttypes.h>
#include <stdbool.h>
#include "byteorder.h"
#include "cpu-conf.h"
#include "kernel_types.h"
#include "net/ng_icmpv6.h"
#include "net/ng_netbase.h"
#include "net/ng_ndp.h"
#include "net/ng_protnum.h"
#include "thread.h"
#include "utlist.h"
#include "net/ng_ipv6/nc.h"
#include "net/ng_ipv6/netif.h"
#include "net/ng_ipv6.h"
#define ENABLE_DEBUG (0)
#include "debug.h"
#define _MAX_L2_ADDR_LEN (8U)
static char _stack[NG_IPV6_STACK_SIZE];
#if ENABLE_DEBUG
static char addr_str[NG_IPV6_ADDR_MAX_STR_LEN];
#endif
kernel_pid_t ng_ipv6_pid = KERNEL_PID_UNDEF;
/* handles NG_NETAPI_MSG_TYPE_RCV commands */
static void _receive(ng_pktsnip_t *pkt);
/* dispatches received IPv6 packet for upper layer */
static void _dispatch_rcv_pkt(ng_nettype_t type, uint32_t demux_ctx,
ng_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(ng_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(ng_pktsnip_t *pkt);
kernel_pid_t ng_ipv6_init(void)
{
if (ng_ipv6_pid == KERNEL_PID_UNDEF) {
ng_ipv6_pid = thread_create(_stack, sizeof(_stack), NG_IPV6_PRIO,
CREATE_STACKTEST, _event_loop, NULL, "ipv6");
}
return ng_ipv6_pid;
}
void ng_ipv6_demux(kernel_pid_t iface, ng_pktsnip_t *pkt, uint8_t nh)
{
int receiver_num;
pkt->type = ng_nettype_from_protnum(nh);
switch (nh) {
case NG_PROTNUM_ICMPV6:
ng_icmpv6_demux(iface, pkt);
break;
#ifdef MODULE_NG_IPV6_EXT
case NG_PROTNUM_IPV6_EXT_HOPOPT:
case NG_PROTNUM_IPV6_EXT_DST:
case NG_PROTNUM_IPV6_EXT_RH:
case NG_PROTNUM_IPV6_EXT_FRAG:
case NG_PROTNUM_IPV6_EXT_AH:
case NG_PROTNUM_IPV6_EXT_ESP:
case NG_PROTNUM_IPV6_EXT_MOB:
if (!ng_ipv6_ext_demux(iface, pkt, nh)) {
DEBUG("ipv6: unable to parse extension headers.\n");
ng_pktbuf_release(pkt);
return;
}
#endif
case NG_PROTNUM_IPV6:
_decapsulate(pkt);
break;
default:
break;
}
receiver_num = ng_netreg_num(pkt->type, NG_NETREG_DEMUX_CTX_ALL) +
ng_netreg_num(NG_NETTYPE_IPV6, nh);
if (receiver_num == 0) {
DEBUG("ipv6: unable to forward packet as no one is interested in it\n");
ng_pktbuf_release(pkt);
return;
}
ng_pktbuf_hold(pkt, receiver_num - 1);
/* IPv6 is not interested anymore so `- 1` */
_dispatch_rcv_pkt(pkt->type, NG_NETREG_DEMUX_CTX_ALL, pkt);
_dispatch_rcv_pkt(NG_NETTYPE_IPV6, nh, pkt);
}
/* internal functions */
static void *_event_loop(void *args)
{
msg_t msg, reply, msg_q[NG_IPV6_MSG_QUEUE_SIZE];
ng_netreg_entry_t me_reg;
(void)args;
msg_init_queue(msg_q, NG_IPV6_MSG_QUEUE_SIZE);
me_reg.demux_ctx = NG_NETREG_DEMUX_CTX_ALL;
me_reg.pid = thread_getpid();
/* register interest in all IPv6 packets */
ng_netreg_register(NG_NETTYPE_IPV6, &me_reg);
/* preinitialize ACK */
reply.type = NG_NETAPI_MSG_TYPE_ACK;
/* start event loop */
while (1) {
DEBUG("ipv6: waiting for incoming message.\n");
msg_receive(&msg);
switch (msg.type) {
case NG_NETAPI_MSG_TYPE_RCV:
DEBUG("ipv6: NG_NETAPI_MSG_TYPE_RCV received\n");
_receive((ng_pktsnip_t *)msg.content.ptr);
break;
case NG_NETAPI_MSG_TYPE_SND:
DEBUG("ipv6: NG_NETAPI_MSG_TYPE_SND received\n");
_send((ng_pktsnip_t *)msg.content.ptr, true);
break;
case NG_NETAPI_MSG_TYPE_GET:
case NG_NETAPI_MSG_TYPE_SET:
DEBUG("ipv6: reply to unsupported get/set\n");
reply.content.value = -ENOTSUP;
msg_reply(&msg, &reply);
break;
case NG_NDP_MSG_RTR_TIMEOUT:
DEBUG("ipv6: Router timeout received\n");
((ng_ipv6_nc_t *)msg.content.ptr)->flags &= ~NG_IPV6_NC_IS_ROUTER;
break;
case NG_NDP_MSG_ADDR_TIMEOUT:
DEBUG("ipv6: Router advertisement timer event received\n");
ng_ipv6_netif_remove_addr(KERNEL_PID_UNDEF,
(ng_ipv6_addr_t *)msg.content.ptr);
break;
case NG_NDP_MSG_NBR_SOL_RETRANS:
DEBUG("ipv6: Neigbor solicitation retransmission timer event received\n");
ng_ndp_retrans_nbr_sol((ng_ipv6_nc_t *)msg.content.ptr);
break;
case NG_NDP_MSG_NC_STATE_TIMEOUT:
DEBUG("ipv6: Neigbor cace state timeout received\n");
ng_ndp_state_timeout((ng_ipv6_nc_t *)msg.content.ptr);
break;
default:
break;
}
}
return NULL;
}
#ifdef MODULE_NG_SIXLOWPAN
static void _send_to_iface(kernel_pid_t iface, ng_pktsnip_t *pkt)
{
ng_ipv6_netif_t *if_entry = ng_ipv6_netif_get(iface);
((ng_netif_hdr_t *)pkt->data)->if_pid = iface;
if ((if_entry != NULL) && (if_entry->flags & NG_IPV6_NETIF_FLAGS_SIXLOWPAN)) {
DEBUG("ipv6: send to 6LoWPAN instead\n");
ng_netreg_entry_t *reg = ng_netreg_lookup(NG_NETTYPE_SIXLOWPAN,
NG_NETREG_DEMUX_CTX_ALL);
if (reg != NULL) {
ng_pktbuf_hold(pkt, ng_netreg_num(NG_NETTYPE_SIXLOWPAN,
NG_NETREG_DEMUX_CTX_ALL) - 1);
}
else {
DEBUG("ipv6: no 6LoWPAN thread found");
}
while (reg) {
ng_netapi_send(reg->pid, pkt);
reg = ng_netreg_getnext(reg);
}
}
else {
ng_netapi_send(iface, pkt);
}
}
#else
static inline void _send_to_iface(kernel_pid_t iface, ng_pktsnip_t *pkt)
{
((ng_netif_hdr_t *)pkt->data)->if_pid = iface;
ng_netapi_send(iface, pkt);
}
#endif
/* functions for sending */
static void _send_unicast(kernel_pid_t iface, uint8_t *dst_l2addr,
uint16_t dst_l2addr_len, ng_pktsnip_t *pkt)
{
ng_pktsnip_t *netif;
if (pkt->type == NG_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 ng_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 = ng_pktbuf_remove_snip(pkt, pkt);
}
DEBUG("ipv6: add to interface header to packet\n");
netif = ng_netif_hdr_build(NULL, 0, dst_l2addr, dst_l2addr_len);
if (netif == NULL) {
DEBUG("ipv6: error on interface header allocation, dropping packet\n");
ng_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, ng_pktsnip_t *ipv6,
ng_pktsnip_t *payload)
{
int res;
ng_ipv6_hdr_t *hdr = ipv6->data;
hdr->len = byteorder_htons(ng_pkt_len(payload));
DEBUG("ipv6: set payload length to %zu (network byteorder %04" PRIx16 ")\n",
ng_pkt_len(payload), hdr->len.u16);
/* check if e.g. extension header was not already marked */
if (hdr->nh == NG_PROTNUM_RESERVED) {
hdr->nh = ng_nettype_to_protnum(payload->type);
/* if still reserved: mark no next header */
if (hdr->nh == NG_PROTNUM_RESERVED) {
hdr->nh = NG_PROTNUM_IPV6_NONXT;
}
}
DEBUG("ipv6: set next header to %" PRIu8 "\n", hdr->nh);
if (hdr->hl == 0) {
hdr->hl = ng_ipv6_netif_get(iface)->cur_hl;
}
if (ng_ipv6_addr_is_unspecified(&hdr->src)) {
ng_ipv6_addr_t *src = ng_ipv6_netif_find_best_src_addr(iface, &hdr->dst);
if (src != NULL) {
DEBUG("ipv6: set packet source to %s\n",
ng_ipv6_addr_to_str(addr_str, src, sizeof(addr_str)));
memcpy(&hdr->src, src, sizeof(ng_ipv6_addr_t));
}
/* Otherwise leave unspecified */
}
DEBUG("ipv6: calculate checksum for upper header.\n");
#if NG_NETIF_NUMOF > 1
if (payload->users > 1) {
ng_pktsnip_t *ptr = ipv6;
/* We deal with multiple interfaces here (multicast) => possible
* different source addresses => duplication of payload needed */
while (ptr != payload) {
/* duplicate everything including payload */
ptr->next = ng_pktbuf_start_write(ptr->next);
if (ptr->next == NULL) {
DEBUG("ipv6: unable to get write access to payload, drop it\n");
return -ENOBUFS;
}
ptr = ptr->next;
}
}
#endif /* NG_NETIF_NUMOF */
if ((res = ng_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, ng_pktsnip_t *pkt,
ng_pktsnip_t *netif)
{
DEBUG("ipv6: send multicast over interface %" PRIkernel_pid "\n", iface);
/* mark as multicast */
((ng_netif_hdr_t *)netif->data)->flags |= NG_NETIF_HDR_FLAGS_MULTICAST;
/* and send to interface */
_send_to_iface(iface, pkt);
}
static void _send_multicast(kernel_pid_t iface, ng_pktsnip_t *pkt,
ng_pktsnip_t *ipv6, ng_pktsnip_t *payload,
bool prep_hdr)
{
ng_pktsnip_t *netif;
kernel_pid_t ifs[NG_NETIF_NUMOF];
if (iface == KERNEL_PID_UNDEF) {
/* get list of interfaces */
size_t ifnum = ng_netif_get(ifs);
/* throw away packet if no one is interested */
if (ifnum == 0) {
DEBUG("ipv6: no interfaces registered, dropping packet\n");
ng_pktbuf_release(pkt);
return;
}
}
#if NG_NETIF_NUMOF > 1
/* netif header not present: send over all interfaces */
if (iface == KERNEL_PID_UNDEF) {
/* send packet to link layer */
ng_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 */
ipv6 = ng_pktbuf_start_write(ipv6);
if (ipv6 == NULL) {
DEBUG("ipv6: unable to get write access to IPv6 header, "
"for interface %" PRIkernel_pid "\n", ifs[i]);
ng_pktbuf_release(pkt);
return;
}
if (_fill_ipv6_hdr(ifs[i], ipv6, payload) < 0) {
/* error on filling up header */
ng_pktbuf_release(pkt);
return;
}
}
/* allocate interface header */
netif = ng_netif_hdr_build(NULL, 0, NULL, 0);
if (netif == NULL) {
DEBUG("ipv6: error on interface header allocation, "
"dropping packet\n");
ng_pktbuf_release(pkt);
return;
}
LL_PREPEND(pkt, netif);
_send_multicast_over_iface(iface, pkt, netif);
}
}
else {
/* iface != KERNEL_PID_UNDEF implies that netif header is present */
if (prep_hdr) {
if (_fill_ipv6_hdr(iface, ipv6, payload) < 0) {
/* error on filling up header */
ng_pktbuf_release(pkt);
return;
}
}
netif = pkt;
_send_multicast_over_iface(iface, pkt, netif);
}
#else /* NG_NETIF_NUMOF */
if (iface == KERNEL_PID_UNDEF) {
iface = ifs[0];
/* allocate interface header */
netif = ng_netif_hdr_build(NULL, 0, NULL, 0);
if (netif == NULL) {
DEBUG("ipv6: error on interface header allocation, "
"dropping packet\n");
ng_pktbuf_release(pkt);
return;
}
LL_PREPEND(pkt, netif);
}
else {
netif = pkt;
}
if (prep_hdr) {
if (_fill_ipv6_hdr(iface, ipv6, payload) < 0) {
/* error on filling up header */
ng_pktbuf_release(pkt);
return;
}
}
_send_multicast_over_iface(iface, pkt, netif);
#endif /* NG_NETIF_NUMOF */
}
static void _send(ng_pktsnip_t *pkt, bool prep_hdr)
{
kernel_pid_t iface = KERNEL_PID_UNDEF;
ng_pktsnip_t *ipv6, *payload;
ng_ipv6_hdr_t *hdr;
/* seize payload as temporary variable */
payload = ng_pktbuf_start_write(pkt);
if (payload == NULL) {
DEBUG("ipv6: unable to get write access to packet, dropping packet\n");
ng_pktbuf_release(pkt);
return;
}
pkt = payload; /* Reset pkt from temporary variable */
/* get IPv6 snip and (if present) generic interface header */
if (pkt->type == NG_NETTYPE_NETIF) {
/* If there is already a netif header (routing protocols and
* neighbor discovery might add them to preset sending interface) */
iface = ((ng_netif_hdr_t *)pkt->data)->if_pid;
ipv6 = pkt->next;
}
else {
ipv6 = pkt;
}
hdr = ipv6->data;
payload = ipv6->next; /* TODO: parse extension headers */
if (ng_ipv6_addr_is_multicast(&hdr->dst)) {
_send_multicast(iface, pkt, ipv6, payload, prep_hdr);
}
else {
uint8_t l2addr_len = NG_IPV6_NC_L2_ADDR_MAX;
uint8_t l2addr[l2addr_len];
iface = ng_ndp_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");
ng_pktbuf_release(pkt);
return;
}
if (prep_hdr) {
if (_fill_ipv6_hdr(iface, ipv6, payload) < 0) {
/* error on filling up header */
ng_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, ng_ipv6_hdr_t *hdr)
{
if (*iface == KERNEL_PID_UNDEF) {
*iface = ng_ipv6_netif_find_by_addr(NULL, &hdr->dst);
return (*iface == KERNEL_PID_UNDEF);
}
else {
return (ng_ipv6_netif_find_addr(*iface, &hdr->dst) == NULL);
}
}
static void _dispatch_rcv_pkt(ng_nettype_t type, uint32_t demux_ctx,
ng_pktsnip_t *pkt)
{
ng_netreg_entry_t *entry = ng_netreg_lookup(type, demux_ctx);
while (entry) {
DEBUG("ipv6: Send receive command for %p to %" PRIu16 "\n", (void *)pkt,
entry->pid);
ng_netapi_receive(entry->pid, pkt);
entry = ng_netreg_getnext(entry);
}
}
static void _receive(ng_pktsnip_t *pkt)
{
kernel_pid_t iface = KERNEL_PID_UNDEF;
ng_pktsnip_t *ipv6, *netif;
ng_ipv6_hdr_t *hdr;
LL_SEARCH_SCALAR(pkt, netif, type, NG_NETTYPE_NETIF);
if (netif != NULL) {
iface = ((ng_netif_hdr_t *)netif->data)->if_pid;
}
if ((pkt->next != NULL) && (pkt->next->type == NG_NETTYPE_IPV6) &&
(pkt->next->size == sizeof(ng_ipv6_hdr_t))) {
/* IP header was already marked. Take it. */
ipv6 = pkt->next;
if (!ng_ipv6_hdr_is(ipv6->data)) {
DEBUG("ipv6: Received packet was not IPv6, dropping packet\n");
ng_pktbuf_release(pkt);
return;
}
}
else {
if (!ng_ipv6_hdr_is(pkt->data)) {
DEBUG("ipv6: Received packet was not IPv6, dropping packet\n");
ng_pktbuf_release(pkt);
return;
}
/* seize ipv6 as a temporary variable */
ipv6 = ng_pktbuf_start_write(pkt);
if (ipv6 == NULL) {
DEBUG("ipv6: unable to get write access to packet, drop it\n");
ng_pktbuf_release(pkt);
return;
}
pkt = ipv6; /* reset pkt from temporary variable */
ipv6 = ng_pktbuf_add(pkt, pkt->data, sizeof(ng_ipv6_hdr_t),
NG_NETTYPE_IPV6);
if (ipv6 == NULL) {
DEBUG("ipv6: error marking IPv6 header, dropping packet\n");
ng_pktbuf_release(pkt);
return;
}
}
/* extract header */
hdr = (ng_ipv6_hdr_t *)ipv6->data;
DEBUG("ipv6: Received (src = %s, ",
ng_ipv6_addr_to_str(addr_str, &(hdr->src), sizeof(addr_str)));
DEBUG("dst = %s, next header = %" PRIu8 ", length = %" PRIu16 ")\n",
ng_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_NG_IPV6_ROUTER /* only routers redirect */
/* redirect to next hop */
DEBUG("ipv6: decrement hop limit to %" PRIu8 "\n", hdr->hl - 1);
/* TODO: check if receiving interface is router */
if (--(hdr->hl) > 0) { /* drop packets that *reach* Hop Limit 0 */
ng_pktsnip_t *tmp = pkt;
DEBUG("ipv6: forward packet to next hop\n");
/* pkt might not be writable yet, if header was given above */
pkt = ng_pktbuf_start_write(tmp);
ipv6 = ng_pktbuf_start_write(ipv6);
if ((ipv6 == NULL) || (pkt == NULL)) {
DEBUG("ipv6: unable to get write access to packet: dropping it\n");
ng_pktbuf_release(tmp);
return;
}
ng_pktbuf_release(ipv6->next); /* remove headers around IPV6 */
ipv6->next = pkt; /* reorder for sending */
pkt->next = NULL;
_send(ipv6, false);
}
else {
DEBUG("ipv6: hop limit reached 0: drop packet\n");
ng_pktbuf_release(pkt);
return;
}
#else /* MODULE_NG_IPV6_ROUTER */
DEBUG("ipv6: dropping packet\n");
/* non rounting hosts just drop the packet */
ng_pktbuf_release(pkt);
return;
#endif /* MODULE_NG_IPV6_ROUTER */
}
/* IPv6 internal demuxing (ICMPv6, Extension headers etc.) */
ng_ipv6_demux(iface, pkt, hdr->nh);
}
static void _decapsulate(ng_pktsnip_t *pkt)
{
ng_pktsnip_t *ptr = pkt;
pkt->type = NG_NETTYPE_UNDEF; /* prevent payload (the encapsulated packet)
* from being removed */
/* Remove encapsulating IPv6 header */
while ((ptr->next != NULL) && (ptr->next->type == NG_NETTYPE_IPV6)) {
ng_pktbuf_remove_snip(pkt, pkt->next);
}
pkt->type = NG_NETTYPE_IPV6;
_receive(pkt);
}
/** @} */
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