/* 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 <net/6lowpan.h>
#include <net/ieee802154_netdev.h>
#include <net/mac802154.h>
#include "6lowpan_i.h"
/* don't save pan id, it's intra pan */
struct lowpan_addr {
u8 mode;
union {
/* IPv6 needs big endian here */
__be64 extended_addr;
__be16 short_addr;
} u;
};
struct lowpan_addr_info {
struct lowpan_addr daddr;
struct lowpan_addr saddr;
};
static inline struct
lowpan_addr_info *lowpan_skb_priv(const struct sk_buff *skb)
{
WARN_ON_ONCE(skb_headroom(skb) < sizeof(struct lowpan_addr_info));
return (struct lowpan_addr_info *)(skb->data -
sizeof(struct lowpan_addr_info));
}
/* This callback will be called from AF_PACKET and IPv6 stack, the AF_PACKET
* sockets gives an 8 byte array for addresses only!
*
* TODO I think AF_PACKET DGRAM (sending/receiving) RAW (sending) makes no
* sense here. We should disable it, the right use-case would be AF_INET6
* RAW/DGRAM sockets.
*/
int lowpan_header_create(struct sk_buff *skb, struct net_device *ldev,
unsigned short type, const void *_daddr,
const void *_saddr, unsigned int len)
{
const u8 *saddr = _saddr;
const u8 *daddr = _daddr;
struct lowpan_addr_info *info;
/* TODO:
* if this package isn't ipv6 one, where should it be routed?
*/
if (type != ETH_P_IPV6)
return 0;
if (!saddr)
saddr = ldev->dev_addr;
raw_dump_inline(__func__, "saddr", (unsigned char *)saddr, 8);
raw_dump_inline(__func__, "daddr", (unsigned char *)daddr, 8);
info = lowpan_skb_priv(skb);
/* TODO: Currently we only support extended_addr */
info->daddr.mode = IEEE802154_ADDR_LONG;
memcpy(&info->daddr.u.extended_addr, daddr,
sizeof(info->daddr.u.extended_addr));
info->saddr.mode = IEEE802154_ADDR_LONG;
memcpy(&info->saddr.u.extended_addr, saddr,
sizeof(info->daddr.u.extended_addr));
return 0;
}
static struct sk_buff*
lowpan_alloc_frag(struct sk_buff *skb, int size,
const struct ieee802154_hdr *master_hdr, bool frag1)
{
struct net_device *wdev = lowpan_dev_info(skb->dev)->wdev;
struct sk_buff *frag;
int rc;
frag = alloc_skb(wdev->needed_headroom + wdev->needed_tailroom + size,
GFP_ATOMIC);
if (likely(frag)) {
frag->dev = wdev;
frag->priority = skb->priority;
skb_reserve(frag, wdev->needed_headroom);
skb_reset_network_header(frag);
*mac_cb(frag) = *mac_cb(skb);
if (frag1) {
memcpy(skb_put(frag, skb->mac_len),
skb_mac_header(skb), skb->mac_len);
} else {
rc = wpan_dev_hard_header(frag, wdev,
&master_hdr->dest,
&master_hdr->source, size);
if (rc < 0) {
kfree_skb(frag);
return ERR_PTR(rc);
}
}
} else {
frag = ERR_PTR(-ENOMEM);
}
return frag;
}
static int
lowpan_xmit_fragment(struct sk_buff *skb, const struct ieee802154_hdr *wpan_hdr,
u8 *frag_hdr, int frag_hdrlen,
int offset, int len, bool frag1)
{
struct sk_buff *frag;
raw_dump_inline(__func__, " fragment header", frag_hdr, frag_hdrlen);
frag = lowpan_alloc_frag(skb, frag_hdrlen + len, wpan_hdr, frag1);
if (IS_ERR(frag))
return PTR_ERR(frag);
memcpy(skb_put(frag, frag_hdrlen), frag_hdr, frag_hdrlen);
memcpy(skb_put(frag, len), skb_network_header(skb) + offset, len);
raw_dump_table(__func__, " fragment dump", frag->data, frag->len);
return dev_queue_xmit(frag);
}
static int
lowpan_xmit_fragmented(struct sk_buff *skb, struct net_device *ldev,
const struct ieee802154_hdr *wpan_hdr,
unsigned int dgram_size, unsigned int dgram_offset)
{
__be16 frag_tag;
u8 frag_hdr[5];
int frag_cap, frag_len, payload_cap, rc;
int skb_unprocessed, skb_offset;
frag_tag = htons(lowpan_dev_info(ldev)->fragment_tag);
lowpan_dev_info(ldev)->fragment_tag++;
frag_hdr[0] = LOWPAN_DISPATCH_FRAG1 | ((dgram_size >> 8) & 0x07);
frag_hdr[1] = dgram_size & 0xff;
memcpy(frag_hdr + 2, &frag_tag, sizeof(frag_tag));
payload_cap = ieee802154_max_payload(wpan_hdr);
frag_len = round_down(payload_cap - LOWPAN_FRAG1_HEAD_SIZE -
skb_network_header_len(skb), 8);
skb_offset = skb_network_header_len(skb);
skb_unprocessed = skb->len - skb->mac_len - skb_offset;
rc = lowpan_xmit_fragment(skb, wpan_hdr, frag_hdr,
LOWPAN_FRAG1_HEAD_SIZE, 0,
frag_len + skb_network_header_len(skb),
true);
if (rc) {
pr_debug("%s unable to send FRAG1 packet (tag: %d)",
__func__, ntohs(frag_tag));
goto err;
}
frag_hdr[0] &= ~LOWPAN_DISPATCH_FRAG1;
frag_hdr[0] |= LOWPAN_DISPATCH_FRAGN;
frag_cap = round_down(payload_cap - LOWPAN_FRAGN_HEAD_SIZE, 8);
do {
dgram_offset += frag_len;
skb_offset += frag_len;
skb_unprocessed -= frag_len;
frag_len = min(frag_cap, skb_unprocessed);
frag_hdr[4] = dgram_offset >> 3;
rc = lowpan_xmit_fragment(skb, wpan_hdr, frag_hdr,
LOWPAN_FRAGN_HEAD_SIZE, skb_offset,
frag_len, false);
if (rc) {
pr_debug("%s unable to send a FRAGN packet. (tag: %d, offset: %d)\n",
__func__, ntohs(frag_tag), skb_offset);
goto err;
}
} while (skb_unprocessed > frag_cap);
consume_skb(skb);
return NET_XMIT_SUCCESS;
err:
kfree_skb(skb);
return rc;
}
static int lowpan_header(struct sk_buff *skb, struct net_device *ldev,
unsigned int *dgram_size, unsigned int *dgram_offset)
{
struct wpan_dev *wpan_dev = lowpan_dev_info(ldev)->wdev->ieee802154_ptr;
struct ieee802154_addr sa, da;
struct ieee802154_mac_cb *cb = mac_cb_init(skb);
struct lowpan_addr_info info;
void *daddr, *saddr;
memcpy(&info, lowpan_skb_priv(skb), sizeof(info));
/* TODO: Currently we only support extended_addr */
daddr = &info.daddr.u.extended_addr;
saddr = &info.saddr.u.extended_addr;
*dgram_size = skb->len;
lowpan_header_compress(skb, ldev, ETH_P_IPV6, daddr, saddr, skb->len);
/* dgram_offset = (saved bytes after compression) + lowpan header len */
*dgram_offset = (*dgram_size - skb->len) + skb_network_header_len(skb);
cb->type = IEEE802154_FC_TYPE_DATA;
/* prepare wpan address data */
sa.mode = IEEE802154_ADDR_LONG;
sa.pan_id = wpan_dev->pan_id;
sa.extended_addr = ieee802154_devaddr_from_raw(saddr);
/* intra-PAN communications */
da.pan_id = sa.pan_id;
/* if the destination address is the broadcast address, use the
* corresponding short address
*/
if (lowpan_is_addr_broadcast((const u8 *)daddr)) {
da.mode = IEEE802154_ADDR_SHORT;
da.short_addr = cpu_to_le16(IEEE802154_ADDR_BROADCAST);
cb->ackreq = false;
} else {
da.mode = IEEE802154_ADDR_LONG;
da.extended_addr = ieee802154_devaddr_from_raw(daddr);
cb->ackreq = wpan_dev->ackreq;
}
return wpan_dev_hard_header(skb, lowpan_dev_info(ldev)->wdev, &da, &sa,
0);
}
netdev_tx_t lowpan_xmit(struct sk_buff *skb, struct net_device *ldev)
{
struct ieee802154_hdr wpan_hdr;
int max_single, ret;
unsigned int dgram_size, dgram_offset;
pr_debug("package xmit\n");
/* We must take a copy of the skb before we modify/replace the ipv6
* header as the header could be used elsewhere
*/
skb = skb_unshare(skb, GFP_ATOMIC);
if (!skb)
return NET_XMIT_DROP;
ret = lowpan_header(skb, ldev, &dgram_size, &dgram_offset);
if (ret < 0) {
kfree_skb(skb);
return NET_XMIT_DROP;
}
if (ieee802154_hdr_peek(skb, &wpan_hdr) < 0) {
kfree_skb(skb);
return NET_XMIT_DROP;
}
max_single = ieee802154_max_payload(&wpan_hdr);
if (skb_tail_pointer(skb) - skb_network_header(skb) <= max_single) {
skb->dev = lowpan_dev_info(ldev)->wdev;
return dev_queue_xmit(skb);
} else {
netdev_tx_t rc;
pr_debug("frame is too big, fragmentation is needed\n");
rc = lowpan_xmit_fragmented(skb, ldev, &wpan_hdr, dgram_size,
dgram_offset);
return rc < 0 ? NET_XMIT_DROP : rc;
}
}
