zephyr/subsys/net/ip/l2/ethernet.c

314 lines
8.3 KiB
C

/*
* Copyright (c) 2016 Intel Corporation.
*
* SPDX-License-Identifier: Apache-2.0
*/
#if defined(CONFIG_NET_DEBUG_L2_ETHERNET)
#define SYS_LOG_DOMAIN "net/ethernet"
#define NET_LOG_ENABLED 1
#endif
#include <net/net_core.h>
#include <net/net_l2.h>
#include <net/net_if.h>
#include <net/ethernet.h>
#include <net/arp.h>
#include "net_private.h"
#include "ipv6.h"
#if defined(CONFIG_NET_IPV6)
static const struct net_eth_addr multicast_eth_addr = {
{ 0x33, 0x33, 0x00, 0x00, 0x00, 0x00 } };
#endif
static const struct net_eth_addr broadcast_eth_addr = {
{ 0xff, 0xff, 0xff, 0xff, 0xff, 0xff } };
const struct net_eth_addr *net_eth_broadcast_addr(void)
{
return &broadcast_eth_addr;
}
#if defined(CONFIG_NET_DEBUG_L2_ETHERNET)
#define print_ll_addrs(pkt, type, len) \
do { \
char out[sizeof("xx:xx:xx:xx:xx:xx")]; \
\
snprintk(out, sizeof(out), "%s", \
net_sprint_ll_addr(net_pkt_ll_src(pkt)->addr, \
sizeof(struct net_eth_addr))); \
\
NET_DBG("src %s dst %s type 0x%x len %zu", out, \
net_sprint_ll_addr(net_pkt_ll_dst(pkt)->addr, \
sizeof(struct net_eth_addr)), \
type, (size_t)len); \
} while (0)
#else
#define print_ll_addrs(...)
#endif /* CONFIG_NET_DEBUG_L2_ETHERNET */
static inline void ethernet_update_length(struct net_if *iface,
struct net_pkt *pkt)
{
u16_t len;
/* Let's check IP payload's length. If it's smaller than 46 bytes,
* i.e. smaller than minimal Ethernet frame size minus ethernet
* header size,then Ethernet has padded so it fits in the minimal
* frame size of 60 bytes. In that case, we need to get rid of it.
*/
if (net_pkt_family(pkt) == AF_INET) {
len = ((NET_IPV4_HDR(pkt)->len[0] << 8) +
NET_IPV4_HDR(pkt)->len[1]);
} else {
len = ((NET_IPV6_HDR(pkt)->len[0] << 8) +
NET_IPV6_HDR(pkt)->len[1]) +
NET_IPV6H_LEN;
}
if (len < NET_ETH_MINIMAL_FRAME_SIZE - sizeof(struct net_eth_hdr)) {
struct net_buf *frag;
for (frag = pkt->frags; frag; frag = frag->frags) {
if (frag->len < len) {
len -= frag->len;
} else {
frag->len = len;
len = 0;
}
}
}
}
static enum net_verdict ethernet_recv(struct net_if *iface,
struct net_pkt *pkt)
{
struct net_eth_hdr *hdr = NET_ETH_HDR(pkt);
struct net_linkaddr *lladdr;
sa_family_t family;
switch (ntohs(hdr->type)) {
case NET_ETH_PTYPE_IP:
case NET_ETH_PTYPE_ARP:
net_pkt_set_family(pkt, AF_INET);
family = AF_INET;
break;
case NET_ETH_PTYPE_IPV6:
net_pkt_set_family(pkt, AF_INET6);
family = AF_INET6;
break;
default:
NET_DBG("Unknown hdr type 0x%04x", hdr->type);
return NET_DROP;
}
/* Set the pointers to ll src and dst addresses */
lladdr = net_pkt_ll_src(pkt);
lladdr->addr = ((struct net_eth_hdr *)net_pkt_ll(pkt))->src.addr;
lladdr->len = sizeof(struct net_eth_addr);
lladdr->type = NET_LINK_ETHERNET;
lladdr = net_pkt_ll_dst(pkt);
lladdr->addr = ((struct net_eth_hdr *)net_pkt_ll(pkt))->dst.addr;
lladdr->len = sizeof(struct net_eth_addr);
lladdr->type = NET_LINK_ETHERNET;
print_ll_addrs(pkt, ntohs(hdr->type), net_pkt_get_len(pkt));
if (!net_eth_is_addr_broadcast((struct net_eth_addr *)lladdr->addr) &&
!net_eth_is_addr_multicast((struct net_eth_addr *)lladdr->addr) &&
!net_linkaddr_cmp(net_if_get_link_addr(iface), lladdr)) {
/* The ethernet frame is not for me as the link addresses
* are different.
*/
NET_DBG("Dropping frame, not for me [%s]",
net_sprint_ll_addr(net_if_get_link_addr(iface)->addr,
sizeof(struct net_eth_addr)));
return NET_DROP;
}
net_pkt_set_ll_reserve(pkt, sizeof(struct net_eth_hdr));
net_buf_pull(pkt->frags, net_pkt_ll_reserve(pkt));
#ifdef CONFIG_NET_ARP
if (family == AF_INET && hdr->type == htons(NET_ETH_PTYPE_ARP)) {
NET_DBG("ARP packet from %s received",
net_sprint_ll_addr((u8_t *)hdr->src.addr,
sizeof(struct net_eth_addr)));
return net_arp_input(pkt);
}
#endif
ethernet_update_length(iface, pkt);
return NET_CONTINUE;
}
static inline bool check_if_dst_is_broadcast_or_mcast(struct net_if *iface,
struct net_pkt *pkt)
{
struct net_eth_hdr *hdr = NET_ETH_HDR(pkt);
if (net_ipv4_addr_cmp(&NET_IPV4_HDR(pkt)->dst,
net_ipv4_broadcast_address())) {
/* Broadcast address */
net_pkt_ll_dst(pkt)->addr = (u8_t *)broadcast_eth_addr.addr;
net_pkt_ll_dst(pkt)->len = sizeof(struct net_eth_addr);
net_pkt_ll_src(pkt)->addr = net_if_get_link_addr(iface)->addr;
net_pkt_ll_src(pkt)->len = sizeof(struct net_eth_addr);
return true;
} else if (NET_IPV4_HDR(pkt)->dst.s4_addr[0] == 224) {
/* Multicast address */
hdr->dst.addr[0] = 0x01;
hdr->dst.addr[1] = 0x00;
hdr->dst.addr[2] = 0x5e;
hdr->dst.addr[3] = NET_IPV4_HDR(pkt)->dst.s4_addr[1];
hdr->dst.addr[4] = NET_IPV4_HDR(pkt)->dst.s4_addr[2];
hdr->dst.addr[5] = NET_IPV4_HDR(pkt)->dst.s4_addr[3];
net_pkt_ll_dst(pkt)->len = sizeof(struct net_eth_addr);
net_pkt_ll_src(pkt)->addr = net_if_get_link_addr(iface)->addr;
net_pkt_ll_src(pkt)->len = sizeof(struct net_eth_addr);
return true;
}
return false;
}
static enum net_verdict ethernet_send(struct net_if *iface,
struct net_pkt *pkt)
{
struct net_eth_hdr *hdr = NET_ETH_HDR(pkt);
struct net_buf *frag;
u16_t ptype;
#ifdef CONFIG_NET_ARP
if (net_pkt_family(pkt) == AF_INET) {
struct net_pkt *arp_pkt;
if (check_if_dst_is_broadcast_or_mcast(iface, pkt)) {
goto setup_hdr;
}
arp_pkt = net_arp_prepare(pkt);
if (!arp_pkt) {
return NET_DROP;
}
NET_DBG("Sending arp pkt %p (orig %p) to iface %p",
arp_pkt, pkt, iface);
pkt = arp_pkt;
net_pkt_ll_src(pkt)->addr = (u8_t *)&NET_ETH_HDR(pkt)->src;
net_pkt_ll_src(pkt)->len = sizeof(struct net_eth_addr);
net_pkt_ll_dst(pkt)->addr = (u8_t *)&NET_ETH_HDR(pkt)->dst;
net_pkt_ll_dst(pkt)->len = sizeof(struct net_eth_addr);
/* For ARP message, we do not touch the packet further but will
* send it as it is because the arp.c has prepared the packet
* already.
*/
goto send;
}
#else
NET_DBG("Sending pkt %p to iface %p", pkt, iface);
#endif
/* If the src ll address is multicast or broadcast, then
* what probably happened is that the RX buffer is used
* for sending data back to recipient. We must
* substitute the src address using the real ll address.
*/
if (net_eth_is_addr_broadcast((struct net_eth_addr *)
net_pkt_ll_src(pkt)->addr) ||
net_eth_is_addr_multicast((struct net_eth_addr *)
net_pkt_ll_src(pkt)->addr)) {
net_pkt_ll_src(pkt)->addr = net_pkt_ll_if(pkt)->addr;
net_pkt_ll_src(pkt)->len = net_pkt_ll_if(pkt)->len;
}
/* If the destination address is not set, then use broadcast
* or multicast address.
*/
if (!net_pkt_ll_dst(pkt)->addr) {
#if defined(CONFIG_NET_IPV6)
if (net_pkt_family(pkt) == AF_INET6 &&
net_is_ipv6_addr_mcast(&NET_IPV6_HDR(pkt)->dst)) {
struct net_eth_addr *dst = &NET_ETH_HDR(pkt)->dst;
memcpy(dst, (u8_t *)multicast_eth_addr.addr,
sizeof(struct net_eth_addr) - 4);
memcpy((u8_t *)dst + 2,
(u8_t *)(&NET_IPV6_HDR(pkt)->dst) + 12,
sizeof(struct net_eth_addr) - 2);
net_pkt_ll_dst(pkt)->addr = (u8_t *)dst->addr;
} else
#endif
{
net_pkt_ll_dst(pkt)->addr =
(u8_t *)broadcast_eth_addr.addr;
}
net_pkt_ll_dst(pkt)->len = sizeof(struct net_eth_addr);
NET_DBG("Destination address was not set, using %s",
net_sprint_ll_addr(net_pkt_ll_dst(pkt)->addr,
net_pkt_ll_dst(pkt)->len));
}
setup_hdr:
__unused;
if (net_pkt_family(pkt) == AF_INET) {
ptype = htons(NET_ETH_PTYPE_IP);
} else {
ptype = htons(NET_ETH_PTYPE_IPV6);
}
/* Then go through the fragments and set the ethernet header.
*/
frag = pkt->frags;
NET_ASSERT_INFO(frag, "No data!");
while (frag) {
NET_ASSERT(net_buf_headroom(frag) > sizeof(struct net_eth_addr));
hdr = (struct net_eth_hdr *)(frag->data -
net_pkt_ll_reserve(pkt));
memcpy(&hdr->dst, net_pkt_ll_dst(pkt)->addr,
sizeof(struct net_eth_addr));
memcpy(&hdr->src, net_pkt_ll_src(pkt)->addr,
sizeof(struct net_eth_addr));
hdr->type = ptype;
print_ll_addrs(pkt, ntohs(hdr->type), frag->len);
frag = frag->frags;
}
#ifdef CONFIG_NET_ARP
send:
#endif /* CONFIG_NET_ARP */
net_if_queue_tx(iface, pkt);
return NET_OK;
}
static inline u16_t ethernet_reserve(struct net_if *iface, void *unused)
{
ARG_UNUSED(iface);
ARG_UNUSED(unused);
return sizeof(struct net_eth_hdr);
}
NET_L2_INIT(ETHERNET_L2, ethernet_recv, ethernet_send, ethernet_reserve, NULL);