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Merge pull request #8215 from miri64/gnrc_ipv6/opt/simplify-send

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gnrc_ipv6: clean-up and simplify send handling
This commit is contained in:
Koen Zandberg 2018-07-16 15:21:55 +02:00 committed by GitHub
commit 8903b34924
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GPG Key ID: 4AEE18F83AFDEB23
1 changed files with 180 additions and 174 deletions
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354
sys/net/gnrc/network_layer/ipv6/gnrc_ipv6.c
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@ -341,31 +341,22 @@ static void _send_to_iface(gnrc_netif_t *netif, gnrc_pktsnip_t *pkt)
}
static gnrc_pktsnip_t *_create_netif_hdr(uint8_t *dst_l2addr,
uint16_t dst_l2addr_len,
gnrc_pktsnip_t *pkt)
unsigned dst_l2addr_len,
gnrc_pktsnip_t *pkt,
uint8_t flags)
{
gnrc_pktsnip_t *netif_hdr = gnrc_netif_hdr_build(NULL, 0, dst_l2addr, dst_l2addr_len);
gnrc_netif_hdr_t *hdr;
if (netif_hdr == 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 netif 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_hdr->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);
}
hdr = netif_hdr->data;
/* previous netif header might have been allocated by some higher layer
* to provide some flags (provided to us via netif_flags). */
hdr->flags = flags;
/* add netif_hdr to front of the pkt list */
LL_PREPEND(pkt, netif_hdr);
@ -373,35 +364,29 @@ static gnrc_pktsnip_t *_create_netif_hdr(uint8_t *dst_l2addr,
return pkt;
}
/* functions for sending */
static void _send_unicast(gnrc_netif_t *netif, uint8_t *dst_l2addr,
uint16_t dst_l2addr_len, gnrc_pktsnip_t *pkt)
static bool _is_ipv6_hdr(gnrc_pktsnip_t *hdr)
{
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", netif->pid);
/* and send to interface */
#ifdef MODULE_NETSTATS_IPV6
netif->ipv6.stats.tx_unicast_count++;
#ifdef MODULE_GNRC_IPV6_EXT
return (hdr->type == GNRC_NETTYPE_IPV6) ||
(hdr->type == GNRC_NETTYPE_IPV6_EXT);
#else
return (hdr->type == GNRC_NETTYPE_IPV6);
#endif
_send_to_iface(netif, pkt);
}
static int _fill_ipv6_hdr(gnrc_netif_t *netif, gnrc_pktsnip_t *ipv6,
gnrc_pktsnip_t *payload)
static int _fill_ipv6_hdr(gnrc_netif_t *netif, gnrc_pktsnip_t *ipv6)
{
int res;
ipv6_hdr_t *hdr = ipv6->data;
gnrc_pktsnip_t *payload, *prev;
hdr->len = byteorder_htons(gnrc_pkt_len(payload));
hdr->len = byteorder_htons(gnrc_pkt_len(ipv6->next));
DEBUG("ipv6: set payload length to %u (network byteorder %04" PRIx16 ")\n",
(unsigned) gnrc_pkt_len(payload), hdr->len.u16);
(unsigned)byteorder_ntohs(hdr->len), 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);
hdr->nh = gnrc_nettype_to_protnum(ipv6->next->type);
/* if still reserved: mark no next header */
if (hdr->nh == PROTNUM_RESERVED) {
@ -437,8 +422,24 @@ static int _fill_ipv6_hdr(gnrc_netif_t *netif, gnrc_pktsnip_t *ipv6,
}
}
DEBUG("ipv6: write protect up to payload to calculate checksum\n");
payload = ipv6;
prev = ipv6;
do {
gnrc_pktsnip_t *tmp;
/* IPv6 header itself was already write-protected in caller function,
* just write protect extension headers and payload header */
payload = payload->next;
tmp = gnrc_pktbuf_start_write(payload);
if (tmp == NULL) {
DEBUG("ipv6: unable to get write access to IPv6 extension or payload header\n");
gnrc_pktbuf_release(ipv6);
return -ENOMEM;
}
prev->next = payload;
prev = payload;
} while (_is_ipv6_hdr(payload));
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");
@ -449,12 +450,60 @@ static int _fill_ipv6_hdr(gnrc_netif_t *netif, gnrc_pktsnip_t *ipv6,
return 0;
}
static inline void _send_multicast_over_iface(gnrc_netif_t *netif,
gnrc_pktsnip_t *pkt)
static bool _safe_fill_ipv6_hdr(gnrc_netif_t *netif, gnrc_pktsnip_t *pkt,
bool prep_hdr)
{
if (prep_hdr && (_fill_ipv6_hdr(netif, pkt) < 0)) {
/* error on filling up header */
gnrc_pktbuf_release(pkt);
return false;
}
return true;
}
/* functions for sending */
static void _send_unicast(gnrc_pktsnip_t *pkt, bool prep_hdr,
gnrc_netif_t *netif, ipv6_hdr_t *ipv6_hdr,
uint8_t netif_hdr_flags)
{
gnrc_ipv6_nib_nc_t nce;
DEBUG("ipv6: send unicast\n");
if (gnrc_ipv6_nib_get_next_hop_l2addr(&ipv6_hdr->dst, netif, pkt,
&nce) < 0) {
/* packet is released by NIB */
DEBUG("ipv6: no link-layer address or interface for next hop to %s",
ipv6_addr_to_str(addr_str, &ipv6_hdr->dst, sizeof(addr_str)));
return;
}
netif = gnrc_netif_get_by_pid(gnrc_ipv6_nib_nc_get_iface(&nce));
assert(netif != NULL);
if (_safe_fill_ipv6_hdr(netif, pkt, prep_hdr)) {
DEBUG("ipv6: add interface header to packet\n");
if ((pkt = _create_netif_hdr(nce.l2addr, nce.l2addr_len, pkt,
netif_hdr_flags)) == NULL) {
return;
}
DEBUG("ipv6: send unicast over interface %" PRIkernel_pid "\n",
netif->pid);
/* and send to interface */
#ifdef MODULE_NETSTATS_IPV6
netif->ipv6.stats.tx_unicast_count++;
#endif
_send_to_iface(netif, pkt);
}
}
static inline void _send_multicast_over_iface(gnrc_pktsnip_t *pkt,
gnrc_netif_t *netif,
uint8_t netif_hdr_flags)
{
if ((pkt = _create_netif_hdr(NULL, 0, pkt,
netif_hdr_flags |
GNRC_NETIF_HDR_FLAGS_MULTICAST)) == NULL) {
return;
}
DEBUG("ipv6: send multicast over interface %" PRIkernel_pid "\n", netif->pid);
/* mark as multicast */
((gnrc_netif_hdr_t *)pkt->data)->flags |= GNRC_NETIF_HDR_FLAGS_MULTICAST;
#ifdef MODULE_NETSTATS_IPV6
netif->ipv6.stats.tx_mcast_count++;
#endif
@ -462,9 +511,8 @@ static inline void _send_multicast_over_iface(gnrc_netif_t *netif,
_send_to_iface(netif, pkt);
}
static void _send_multicast(gnrc_netif_t *netif, gnrc_pktsnip_t *pkt,
gnrc_pktsnip_t *ipv6, gnrc_pktsnip_t *payload,
bool prep_hdr)
static void _send_multicast(gnrc_pktsnip_t *pkt, bool prep_hdr,
gnrc_netif_t *netif, uint8_t netif_hdr_flags)
{
size_t ifnum = 0;
@ -487,57 +535,33 @@ static void _send_multicast(gnrc_netif_t *netif, gnrc_pktsnip_t *pkt,
while ((netif = gnrc_netif_iter(netif))) {
if (prep_hdr) {
DEBUG("ipv6: prepare IPv6 header for sending\n");
/* 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) {
if (tmp == NULL) {
DEBUG("ipv6: unable to get write access to IPv6 header, "
"for interface %" PRIkernel_pid "\n", netif->pid);
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(netif, ipv6, tmp) < 0) {
if (_fill_ipv6_hdr(netif, tmp) < 0) {
/* error on filling up header */
gnrc_pktbuf_release(ipv6);
if (tmp != pkt) {
gnrc_pktbuf_release(tmp);
}
gnrc_pktbuf_release(pkt);
return;
}
}
if ((ipv6 = _create_netif_hdr(NULL, 0, ipv6)) == NULL) {
return;
}
_send_multicast_over_iface(netif, ipv6);
_send_multicast_over_iface(pkt, netif, netif_hdr_flags);
}
}
else {
if (prep_hdr) {
if (_fill_ipv6_hdr(netif, ipv6, payload) < 0) {
/* error on filling up header */
gnrc_pktbuf_release(pkt);
return;
}
if (_safe_fill_ipv6_hdr(netif, pkt, prep_hdr)) {
_send_multicast_over_iface(pkt, netif, netif_hdr_flags);
}
_send_multicast_over_iface(netif, pkt);
}
#else /* GNRC_NETIF_NUMOF */
(void)ifnum; /* not used in this build branch */
@ -545,133 +569,115 @@ static void _send_multicast(gnrc_netif_t *netif, gnrc_pktsnip_t *pkt,
netif = gnrc_netif_iter(NULL);
/* allocate interface header */
if ((pkt = _create_netif_hdr(NULL, 0, pkt)) == NULL) {
if ((pkt = _create_netif_hdr(NULL, 0, pkt, netif_hdr_flags)) == NULL) {
return;
}
}
if (prep_hdr) {
if (_fill_ipv6_hdr(netif, ipv6, payload) < 0) {
/* error on filling up header */
gnrc_pktbuf_release(pkt);
return;
}
if (_safe_fill_ipv6_hdr(netif, pkt, prep_hdr)) {
_send_multicast_over_iface(pkt, netif, netif_hdr_flags);
}
_send_multicast_over_iface(netif, pkt);
#endif /* GNRC_NETIF_NUMOF */
}
static void _send_to_self(gnrc_pktsnip_t *pkt, bool prep_hdr,
gnrc_netif_t *netif)
{
uint8_t *rcv_data;
gnrc_pktsnip_t *ptr = pkt, *rcv_pkt;
if (!_safe_fill_ipv6_hdr(netif, pkt, prep_hdr)) {
return;
}
rcv_pkt = gnrc_pktbuf_add(NULL, NULL, gnrc_pkt_len(pkt), 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);
}
}
static void _send(gnrc_pktsnip_t *pkt, bool prep_hdr)
{
gnrc_netif_t *netif = NULL;
gnrc_pktsnip_t *ipv6, *payload;
ipv6_hdr_t *hdr;
gnrc_pktsnip_t *tmp_pkt;
ipv6_hdr_t *ipv6_hdr;
uint8_t netif_hdr_flags = 0U;
/* 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) */
* neighbor discovery might add them to preset sending interface or
* higher layers wants to provide flags to the interface ) */
const gnrc_netif_hdr_t *netif_hdr = pkt->data;
netif = gnrc_netif_get_by_pid(((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) {
/* discard broadcast and multicast flags because those could be
* potentially wrong (dst is later checked to assure that multicast is
* set if dst is a multicast address) */
netif_hdr_flags = netif_hdr->flags &
~(GNRC_NETIF_HDR_FLAGS_BROADCAST |
GNRC_NETIF_HDR_FLAGS_MULTICAST);
tmp_pkt = gnrc_pktbuf_start_write(pkt);
if (tmp_pkt == 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;
/* discard to avoid complex checks for correctness (will be re-added
* with correct addresses anyway as for the case were there is no
* netif header provided)
* Also re-establish temporary pointer used for write protection as
* actual pointer */
pkt = gnrc_pktbuf_remove_snip(tmp_pkt, tmp_pkt);
}
else {
ipv6 = pkt;
if (pkt->type != GNRC_NETTYPE_IPV6) {
DEBUG("ipv6: unexpected packet type\n");
gnrc_pktbuf_release_error(pkt, EINVAL);
return;
}
/* seize payload as temporary variable */
payload = gnrc_pktbuf_start_write(ipv6);
if (payload == NULL) {
tmp_pkt = gnrc_pktbuf_start_write(pkt);
if (tmp_pkt == 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 */
pkt = tmp_pkt;
ipv6_hdr = pkt->data;
if (ipv6_addr_is_multicast(&ipv6_hdr->dst)) {
_send_multicast(pkt, prep_hdr, netif, netif_hdr_flags);
}
else {
pkt = payload; /* pkt is the IPv6 header so we just write-protected it */
}
ipv6 = payload; /* Reset ipv6 from temporary variable */
gnrc_netif_t *tmp_netif = gnrc_netif_get_by_ipv6_addr(&ipv6_hdr->dst);
hdr = ipv6->data;
payload = ipv6->next;
if (ipv6_addr_is_multicast(&hdr->dst)) {
_send_multicast(netif, pkt, ipv6, payload, prep_hdr);
}
else {
gnrc_netif_t *tmp_netif = gnrc_netif_get_by_ipv6_addr(&hdr->dst);
if (ipv6_addr_is_loopback(&hdr->dst) || /* dst is loopback address */
/* or dst registered to a local interface */
(tmp_netif != NULL)) {
uint8_t *rcv_data;
gnrc_pktsnip_t *ptr = ipv6, *rcv_pkt;
if (prep_hdr) {
if (_fill_ipv6_hdr(tmp_netif, 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);
}
if (ipv6_addr_is_loopback(&ipv6_hdr->dst) || /* dst is loopback address */
/* or dst registered to a local interface */
(tmp_netif != NULL)) {
_send_to_self(pkt, prep_hdr, tmp_netif);
}
else {
gnrc_ipv6_nib_nc_t nce;
if (gnrc_ipv6_nib_get_next_hop_l2addr(&hdr->dst, netif, pkt,
&nce) < 0) {
/* packet is released by NIB */
return;
}
netif = gnrc_netif_get_by_pid(gnrc_ipv6_nib_nc_get_iface(&nce));
assert(netif != NULL);
if (prep_hdr) {
if (_fill_ipv6_hdr(netif, ipv6, payload) < 0) {
/* error on filling up header */
gnrc_pktbuf_release(pkt);
return;
}
}
_send_unicast(netif, nce.l2addr,
nce.l2addr_len, pkt);
_send_unicast(pkt, prep_hdr, netif, ipv6_hdr, netif_hdr_flags);
}
}
}