linux/net/ieee802154/6lowpan/rx.c

332 lines
7.5 KiB
C

/* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2
* as published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*/
#include <linux/if_arp.h>
#include <net/6lowpan.h>
#include <net/mac802154.h>
#include <net/ieee802154_netdev.h>
#include "6lowpan_i.h"
#define LOWPAN_DISPATCH_FIRST 0xc0
#define LOWPAN_DISPATCH_FRAG_MASK 0xf8
#define LOWPAN_DISPATCH_NALP 0x00
#define LOWPAN_DISPATCH_ESC 0x40
#define LOWPAN_DISPATCH_HC1 0x42
#define LOWPAN_DISPATCH_DFF 0x43
#define LOWPAN_DISPATCH_BC0 0x50
#define LOWPAN_DISPATCH_MESH 0x80
static int lowpan_give_skb_to_device(struct sk_buff *skb)
{
skb->protocol = htons(ETH_P_IPV6);
skb->dev->stats.rx_packets++;
skb->dev->stats.rx_bytes += skb->len;
return netif_rx(skb);
}
static int lowpan_rx_handlers_result(struct sk_buff *skb, lowpan_rx_result res)
{
switch (res) {
case RX_CONTINUE:
/* nobody cared about this packet */
net_warn_ratelimited("%s: received unknown dispatch\n",
__func__);
/* fall-through */
case RX_DROP_UNUSABLE:
kfree_skb(skb);
/* fall-through */
case RX_DROP:
return NET_RX_DROP;
case RX_QUEUED:
return lowpan_give_skb_to_device(skb);
default:
break;
}
return NET_RX_DROP;
}
static inline bool lowpan_is_frag1(u8 dispatch)
{
return (dispatch & LOWPAN_DISPATCH_FRAG_MASK) == LOWPAN_DISPATCH_FRAG1;
}
static inline bool lowpan_is_fragn(u8 dispatch)
{
return (dispatch & LOWPAN_DISPATCH_FRAG_MASK) == LOWPAN_DISPATCH_FRAGN;
}
static lowpan_rx_result lowpan_rx_h_frag(struct sk_buff *skb)
{
int ret;
if (!(lowpan_is_frag1(*skb_network_header(skb)) ||
lowpan_is_fragn(*skb_network_header(skb))))
return RX_CONTINUE;
ret = lowpan_frag_rcv(skb, *skb_network_header(skb) &
LOWPAN_DISPATCH_FRAG_MASK);
if (ret == 1)
return RX_QUEUED;
/* Packet is freed by lowpan_frag_rcv on error or put into the frag
* bucket.
*/
return RX_DROP;
}
int lowpan_iphc_decompress(struct sk_buff *skb)
{
struct ieee802154_hdr hdr;
if (ieee802154_hdr_peek_addrs(skb, &hdr) < 0)
return -EINVAL;
return lowpan_header_decompress(skb, skb->dev, &hdr.dest, &hdr.source);
}
static lowpan_rx_result lowpan_rx_h_iphc(struct sk_buff *skb)
{
int ret;
if (!lowpan_is_iphc(*skb_network_header(skb)))
return RX_CONTINUE;
/* Setting datagram_offset to zero indicates non frag handling
* while doing lowpan_header_decompress.
*/
lowpan_802154_cb(skb)->d_size = 0;
ret = lowpan_iphc_decompress(skb);
if (ret < 0)
return RX_DROP_UNUSABLE;
return RX_QUEUED;
}
lowpan_rx_result lowpan_rx_h_ipv6(struct sk_buff *skb)
{
if (!lowpan_is_ipv6(*skb_network_header(skb)))
return RX_CONTINUE;
/* Pull off the 1-byte of 6lowpan header. */
skb_pull(skb, 1);
return RX_QUEUED;
}
static inline bool lowpan_is_esc(u8 dispatch)
{
return dispatch == LOWPAN_DISPATCH_ESC;
}
static lowpan_rx_result lowpan_rx_h_esc(struct sk_buff *skb)
{
if (!lowpan_is_esc(*skb_network_header(skb)))
return RX_CONTINUE;
net_warn_ratelimited("%s: %s\n", skb->dev->name,
"6LoWPAN ESC not supported\n");
return RX_DROP_UNUSABLE;
}
static inline bool lowpan_is_hc1(u8 dispatch)
{
return dispatch == LOWPAN_DISPATCH_HC1;
}
static lowpan_rx_result lowpan_rx_h_hc1(struct sk_buff *skb)
{
if (!lowpan_is_hc1(*skb_network_header(skb)))
return RX_CONTINUE;
net_warn_ratelimited("%s: %s\n", skb->dev->name,
"6LoWPAN HC1 not supported\n");
return RX_DROP_UNUSABLE;
}
static inline bool lowpan_is_dff(u8 dispatch)
{
return dispatch == LOWPAN_DISPATCH_DFF;
}
static lowpan_rx_result lowpan_rx_h_dff(struct sk_buff *skb)
{
if (!lowpan_is_dff(*skb_network_header(skb)))
return RX_CONTINUE;
net_warn_ratelimited("%s: %s\n", skb->dev->name,
"6LoWPAN DFF not supported\n");
return RX_DROP_UNUSABLE;
}
static inline bool lowpan_is_bc0(u8 dispatch)
{
return dispatch == LOWPAN_DISPATCH_BC0;
}
static lowpan_rx_result lowpan_rx_h_bc0(struct sk_buff *skb)
{
if (!lowpan_is_bc0(*skb_network_header(skb)))
return RX_CONTINUE;
net_warn_ratelimited("%s: %s\n", skb->dev->name,
"6LoWPAN BC0 not supported\n");
return RX_DROP_UNUSABLE;
}
static inline bool lowpan_is_mesh(u8 dispatch)
{
return (dispatch & LOWPAN_DISPATCH_FIRST) == LOWPAN_DISPATCH_MESH;
}
static lowpan_rx_result lowpan_rx_h_mesh(struct sk_buff *skb)
{
if (!lowpan_is_mesh(*skb_network_header(skb)))
return RX_CONTINUE;
net_warn_ratelimited("%s: %s\n", skb->dev->name,
"6LoWPAN MESH not supported\n");
return RX_DROP_UNUSABLE;
}
static int lowpan_invoke_rx_handlers(struct sk_buff *skb)
{
lowpan_rx_result res;
#define CALL_RXH(rxh) \
do { \
res = rxh(skb); \
if (res != RX_CONTINUE) \
goto rxh_next; \
} while (0)
/* likely at first */
CALL_RXH(lowpan_rx_h_iphc);
CALL_RXH(lowpan_rx_h_frag);
CALL_RXH(lowpan_rx_h_ipv6);
CALL_RXH(lowpan_rx_h_esc);
CALL_RXH(lowpan_rx_h_hc1);
CALL_RXH(lowpan_rx_h_dff);
CALL_RXH(lowpan_rx_h_bc0);
CALL_RXH(lowpan_rx_h_mesh);
rxh_next:
return lowpan_rx_handlers_result(skb, res);
#undef CALL_RXH
}
static inline bool lowpan_is_nalp(u8 dispatch)
{
return (dispatch & LOWPAN_DISPATCH_FIRST) == LOWPAN_DISPATCH_NALP;
}
/* Lookup for reserved dispatch values at:
* https://www.iana.org/assignments/_6lowpan-parameters/_6lowpan-parameters.xhtml#_6lowpan-parameters-1
*
* Last Updated: 2015-01-22
*/
static inline bool lowpan_is_reserved(u8 dispatch)
{
return ((dispatch >= 0x44 && dispatch <= 0x4F) ||
(dispatch >= 0x51 && dispatch <= 0x5F) ||
(dispatch >= 0xc8 && dispatch <= 0xdf) ||
(dispatch >= 0xe8 && dispatch <= 0xff));
}
/* lowpan_rx_h_check checks on generic 6LoWPAN requirements
* in MAC and 6LoWPAN header.
*
* Don't manipulate the skb here, it could be shared buffer.
*/
static inline bool lowpan_rx_h_check(struct sk_buff *skb)
{
__le16 fc = ieee802154_get_fc_from_skb(skb);
/* check on ieee802154 conform 6LoWPAN header */
if (!ieee802154_is_data(fc) ||
!ieee802154_skb_is_intra_pan_addressing(fc, skb))
return false;
/* check if we can dereference the dispatch */
if (unlikely(!skb->len))
return false;
if (lowpan_is_nalp(*skb_network_header(skb)) ||
lowpan_is_reserved(*skb_network_header(skb)))
return false;
return true;
}
static int lowpan_rcv(struct sk_buff *skb, struct net_device *wdev,
struct packet_type *pt, struct net_device *orig_wdev)
{
struct net_device *ldev;
if (wdev->type != ARPHRD_IEEE802154 ||
skb->pkt_type == PACKET_OTHERHOST ||
!lowpan_rx_h_check(skb))
goto drop;
ldev = wdev->ieee802154_ptr->lowpan_dev;
if (!ldev || !netif_running(ldev))
goto drop;
/* Replacing skb->dev and followed rx handlers will manipulate skb. */
skb = skb_share_check(skb, GFP_ATOMIC);
if (!skb)
goto out;
skb->dev = ldev;
/* When receive frag1 it's likely that we manipulate the buffer.
* When recevie iphc we manipulate the data buffer. So we need
* to unshare the buffer.
*/
if (lowpan_is_frag1(*skb_network_header(skb)) ||
lowpan_is_iphc(*skb_network_header(skb))) {
skb = skb_unshare(skb, GFP_ATOMIC);
if (!skb)
goto out;
}
return lowpan_invoke_rx_handlers(skb);
drop:
kfree_skb(skb);
out:
return NET_RX_DROP;
}
static struct packet_type lowpan_packet_type = {
.type = htons(ETH_P_IEEE802154),
.func = lowpan_rcv,
};
void lowpan_rx_init(void)
{
dev_add_pack(&lowpan_packet_type);
}
void lowpan_rx_exit(void)
{
dev_remove_pack(&lowpan_packet_type);
}