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Merge pull request #3675 from authmillenon/gnrc_ipv6/fix/check-mtu

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gnrc_ipv6: check link MTU before sending
This commit is contained in:
Oleg Hahm 2015-08-21 23:45:52 +02:00
commit 8977cc1175
6 changed files with 93 additions and 20 deletions
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17
sys/include/net/gnrc/ipv6/netif.h
View File

@ -28,6 +28,7 @@
#include "kernel_macros.h"
#include "kernel_types.h"
#include "mutex.h"
#include "net/ipv6.h"
#include "net/ipv6/addr.h"
#include "vtimer.h"
@ -51,11 +52,19 @@ extern "C" {
/**
* @brief Default MTU
*
* @see <a href="https://tools.ietf.org/html/rfc2460#section-5">
* RFC 2460, section 5
* </a>
* An interface will choose this MTU if the link-layer's maximum packet size
* (see @ref NETOPT_MAX_PACKET_SIZE) is lesser than the @ref IPV6_MIN_MTU or if it just not
* provide it. For RFC-compatible communication it must be at least @ref IPV6_MIN_MTU.
*
* @note If the scenario the node is used in allows for it and the packet size is predictable,
* a user might choose to set @ref GNRC_IPV6_NETIF_DEFAULT_MTU to a lesser value than
* @ref IPV6_MIN_MTU to optimize for code size (e.g. because it is then possible to omit
* @ref net_gnrc_sixlowpan_frag) and memory usage (e.g. because @ref GNRC_PKTBUF_SIZE
* can be much smaller).
*/
#define GNRC_IPV6_NETIF_DEFAULT_MTU (1280)
#ifndef GNRC_IPV6_NETIF_DEFAULT_MTU
#define GNRC_IPV6_NETIF_DEFAULT_MTU (IPV6_MIN_MTU)
#endif
/**
* @brief Default hop limit

9
sys/include/net/ipv6.h
View File

@ -32,6 +32,15 @@
extern "C" {
#endif
/**
* @brief minimum **M**aximum **T**ransition **U**nit
*
* @see <a href="https://tools.ietf.org/html/rfc4944#section-5.3">
* RFC 2460, section 5.3
* </a>
*/
#define IPV6_MIN_MTU (1280)
#ifdef __cplusplus
}
#endif

2
sys/net/gnrc/link_layer/netdev_eth/gnrc_netdev_eth.c
View File

@ -223,7 +223,7 @@ static inline int _get_max_pkt_sz(uint16_t *value, size_t max_len)
return -EOVERFLOW;
}
*value = ETHERNET_MAX_LEN;
*value = ETHERNET_DATA_LEN;
return sizeof(uint16_t);
}

23
sys/net/gnrc/network_layer/ipv6/gnrc_ipv6.c
View File

@ -11,6 +11,7 @@
*
* @file
*/
#include <assert.h>
#include <errno.h>
#include <inttypes.h>
#include <stdbool.h>
@ -205,31 +206,29 @@ static void *_event_loop(void *args)
return NULL;
}
#ifdef MODULE_GNRC_SIXLOWPAN
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);
((gnrc_netif_hdr_t *)pkt->data)->if_pid = 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;
}
else {
gnrc_netapi_send(iface, pkt);
}
}
#else
static inline void _send_to_iface(kernel_pid_t iface, gnrc_pktsnip_t *pkt)
{
((gnrc_netif_hdr_t *)pkt->data)->if_pid = iface;
#endif
gnrc_netapi_send(iface, pkt);
}
#endif
/* functions for sending */
static void _send_unicast(kernel_pid_t iface, uint8_t *dst_l2addr,

12
sys/net/gnrc/network_layer/ipv6/netif/gnrc_ipv6_netif.c
View File

@ -695,6 +695,7 @@ void gnrc_ipv6_netif_init_by_dev(void)
for (size_t i = 0; i < ifnum; i++) {
ipv6_addr_t addr;
eui64_t iid;
uint16_t mtu;
gnrc_ipv6_netif_t *ipv6_if = gnrc_ipv6_netif_get(ifs[i]);
if (ipv6_if == NULL) {
@ -730,6 +731,7 @@ void gnrc_ipv6_netif_init_by_dev(void)
}
#endif
/* set link-local address */
if ((gnrc_netapi_get(ifs[i], NETOPT_IPV6_IID, 0, &iid,
sizeof(eui64_t)) < 0)) {
mutex_unlock(&ipv6_if->mutex);
@ -740,6 +742,16 @@ void gnrc_ipv6_netif_init_by_dev(void)
ipv6_addr_set_link_local_prefix(&addr);
_add_addr_to_entry(ipv6_if, &addr, 64, 0);
/* set link MTU */
if ((gnrc_netapi_get(ifs[i], NETOPT_MAX_PACKET_SIZE, 0, &mtu,
sizeof(uint16_t)) >= 0)) {
if (mtu >= IPV6_MIN_MTU) {
ipv6_if->mtu = mtu;
}
/* otherwise leave at GNRC_IPV6_NETIF_DEFAULT_MTU as initialized in
* gnrc_ipv6_netif_add() */
}
mutex_unlock(&ipv6_if->mutex);
}
}

50
sys/shell/commands/sc_netif.c
View File

@ -89,6 +89,11 @@ static void _set_usage(char *cmd_name)
" * \"state\" - set the device state\n");
}
static void _mtu_usage(char *cmd_name)
{
printf("usage: %s <if_id> mtu <n>\n", cmd_name);
}
static void _flag_usage(char *cmd_name)
{
printf("usage: %s <if_id> [-]{promisc|autoack|preload|6lo|iphc}\n", cmd_name);
@ -259,8 +264,11 @@ static void _netif_list(kernel_pid_t dev)
}
#ifdef MODULE_GNRC_IPV6_NETIF
if ((entry != NULL) && (entry->flags & GNRC_IPV6_NETIF_FLAGS_SIXLOWPAN)) {
printf("6LO ");
if (entry != NULL) {
printf("MTU:%" PRIu16 " ", entry->mtu);
if (entry->flags & GNRC_IPV6_NETIF_FLAGS_SIXLOWPAN) {
printf("6LO ");
}
linebreak = true;
}
#endif
@ -269,7 +277,7 @@ static void _netif_list(kernel_pid_t dev)
gnrc_sixlowpan_netif_t *sixlo_entry = gnrc_sixlowpan_netif_get(dev);
if ((sixlo_entry != NULL) && (sixlo_entry->iphc_enabled)) {
printf("IPHC ");
printf("IPHC ");
linebreak = true;
}
#endif
@ -683,6 +691,33 @@ static int _netif_del(kernel_pid_t dev, char *addr_str)
#endif
}
static int _netif_mtu(kernel_pid_t dev, char *mtu_str)
{
#ifdef MODULE_GNRC_IPV6_NETIF
int mtu;
gnrc_ipv6_netif_t *entry;
if (((mtu = atoi(mtu_str)) < IPV6_MIN_MTU) || (mtu > UINT16_MAX)) {
printf("error: MTU must be between %" PRIu16 " and %" PRIu16 "\n",
IPV6_MIN_MTU, UINT16_MAX);
return 1;
}
if ((entry = gnrc_ipv6_netif_get(dev)) == NULL) {
puts("error: unable to set MTU.");
return 1;
}
entry->mtu = IPV6_MIN_MTU;
printf("success: set MTU %" PRIu16 " interface %" PRIkernel_pid "\n", mtu,
dev);
return 0;
#else
(void)dev;
(void)mtu_str;
puts("error: unable to set MTU.");
return 1;
#endif
}
/* shell commands */
int _netif_send(int argc, char **argv)
{
@ -777,6 +812,14 @@ int _netif_config(int argc, char **argv)
return _netif_del((kernel_pid_t)dev, argv[3]);
}
else if (strcmp(argv[2], "mtu") == 0) {
if (argc < 4) {
_mtu_usage(argv[0]);
return 1;
}
return _netif_mtu((kernel_pid_t)dev, argv[3]);
}
else {
return _netif_flag(argv[0], dev, argv[2]);
}
@ -789,6 +832,7 @@ int _netif_config(int argc, char **argv)
printf("usage: %s [<if_id>]\n", argv[0]);
_set_usage(argv[0]);
_mtu_usage(argv[0]);
_flag_usage(argv[0]);
_add_usage(argv[0]);
_del_usage(argv[0]);