net/ieee802154/6lowpan/tx.c - linux - Git at Google

 /* 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/ndisc.h>
 #include <net/ieee802154_netdev.h>
 #include <net/mac802154.h>

 #include "6lowpan_i.h"

 #define LOWPAN_FRAG1_HEAD_SIZE	0x4
 #define LOWPAN_FRAGN_HEAD_SIZE	0x5

 struct lowpan_addr_info {
 	struct ieee802154_addr daddr;
 	struct ieee802154_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)
 {
 	struct wpan_dev *wpan_dev = lowpan_802154_dev(ldev)->wdev->ieee802154_ptr;
 	struct lowpan_addr_info *info = lowpan_skb_priv(skb);
 	struct lowpan_802154_neigh *llneigh = NULL;
 	const struct ipv6hdr *hdr = ipv6_hdr(skb);
 	struct neighbour *n;

 	/* TODO:
 	 * if this package isn't ipv6 one, where should it be routed?
 	 */
 	if (type != ETH_P_IPV6)
 		return 0;

 	/* intra-pan communication */
 	info->saddr.pan_id = wpan_dev->pan_id;
 	info->daddr.pan_id = info->saddr.pan_id;

 	if (!memcmp(daddr, ldev->broadcast, EUI64_ADDR_LEN)) {
 		info->daddr.short_addr = cpu_to_le16(IEEE802154_ADDR_BROADCAST);
 		info->daddr.mode = IEEE802154_ADDR_SHORT;
 	} else {
 		__le16 short_addr = cpu_to_le16(IEEE802154_ADDR_SHORT_UNSPEC);

 		n = neigh_lookup(&nd_tbl, &hdr->daddr, ldev);
 		if (n) {
 			llneigh = lowpan_802154_neigh(neighbour_priv(n));
 			read_lock_bh(&n->lock);
 			short_addr = llneigh->short_addr;
 			read_unlock_bh(&n->lock);
 		}

 		if (llneigh &&
 		    lowpan_802154_is_valid_src_short_addr(short_addr)) {
 			info->daddr.short_addr = short_addr;
 			info->daddr.mode = IEEE802154_ADDR_SHORT;
 		} else {
 			info->daddr.mode = IEEE802154_ADDR_LONG;
 			ieee802154_be64_to_le64(&info->daddr.extended_addr,
 						daddr);
 		}

 		if (n)
 			neigh_release(n);
 	}

 	if (!saddr) {
 		if (lowpan_802154_is_valid_src_short_addr(wpan_dev->short_addr)) {
 			info->saddr.mode = IEEE802154_ADDR_SHORT;
 			info->saddr.short_addr = wpan_dev->short_addr;
 		} else {
 			info->saddr.mode = IEEE802154_ADDR_LONG;
 			info->saddr.extended_addr = wpan_dev->extended_addr;
 		}
 	} else {
 		info->saddr.mode = IEEE802154_ADDR_LONG;
 		ieee802154_be64_to_le64(&info->saddr.extended_addr, saddr);
 	}

 	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_802154_dev(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) {
 			skb_put_data(frag, 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);

 	skb_put_data(frag, frag_hdr, frag_hdrlen);
 	skb_put_data(frag, 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, u16 dgram_size,
 		       u16 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_802154_dev(ldev)->fragment_tag);
 	lowpan_802154_dev(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);

 	ldev->stats.tx_packets++;
 	ldev->stats.tx_bytes += dgram_size;
 	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,
 			 u16 *dgram_size, u16 *dgram_offset)
 {
 	struct wpan_dev *wpan_dev = lowpan_802154_dev(ldev)->wdev->ieee802154_ptr;
 	struct ieee802154_mac_cb *cb = mac_cb_init(skb);
 	struct lowpan_addr_info info;

 	memcpy(&info, lowpan_skb_priv(skb), sizeof(info));

 	*dgram_size = skb->len;
 	lowpan_header_compress(skb, ldev, &info.daddr, &info.saddr);
 	/* 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;

 	if (info.daddr.mode == IEEE802154_ADDR_SHORT &&
 	    ieee802154_is_broadcast_short_addr(info.daddr.short_addr))
 		cb->ackreq = false;
 	else
 		cb->ackreq = wpan_dev->ackreq;

 	return wpan_dev_hard_header(skb, lowpan_802154_dev(ldev)->wdev,
 				    &info.daddr, &info.saddr, 0);
 }

 netdev_tx_t lowpan_xmit(struct sk_buff *skb, struct net_device *ldev)
 {
 	struct ieee802154_hdr wpan_hdr;
 	int max_single, ret;
 	u16 dgram_size, dgram_offset;

 	pr_debug("package xmit\n");

 	WARN_ON_ONCE(skb->len > IPV6_MIN_MTU);

 	/* We must take a copy of the skb before we modify/replace the ipv6
 	 * header as the header could be used elsewhere
 	 */
 	if (unlikely(skb_headroom(skb) < ldev->needed_headroom ||
 		     skb_tailroom(skb) < ldev->needed_tailroom)) {
 		struct sk_buff *nskb;

 		nskb = skb_copy_expand(skb, ldev->needed_headroom,
 				       ldev->needed_tailroom, GFP_ATOMIC);
 		if (likely(nskb)) {
 			consume_skb(skb);
 			skb = nskb;
 		} else {
 			kfree_skb(skb);
 			return NET_XMIT_DROP;
 		}
 	} else {
 		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_802154_dev(ldev)->wdev;
 		ldev->stats.tx_packets++;
 		ldev->stats.tx_bytes += dgram_size;
 		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;
 	}
 }
	/* 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/ndisc.h>
	#include <net/ieee802154_netdev.h>
	#include <net/mac802154.h>

	#include "6lowpan_i.h"

	#define LOWPAN_FRAG1_HEAD_SIZE 0x4
	#define LOWPAN_FRAGN_HEAD_SIZE 0x5

	struct lowpan_addr_info {
	struct ieee802154_addr daddr;
	struct ieee802154_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)
	{
	struct wpan_dev *wpan_dev = lowpan_802154_dev(ldev)->wdev->ieee802154_ptr;
	struct lowpan_addr_info *info = lowpan_skb_priv(skb);
	struct lowpan_802154_neigh *llneigh = NULL;
	const struct ipv6hdr *hdr = ipv6_hdr(skb);
	struct neighbour *n;

	/* TODO:
	* if this package isn't ipv6 one, where should it be routed?
	*/
	if (type != ETH_P_IPV6)
	return 0;

	/* intra-pan communication */
	info->saddr.pan_id = wpan_dev->pan_id;
	info->daddr.pan_id = info->saddr.pan_id;

	if (!memcmp(daddr, ldev->broadcast, EUI64_ADDR_LEN)) {
	info->daddr.short_addr = cpu_to_le16(IEEE802154_ADDR_BROADCAST);
	info->daddr.mode = IEEE802154_ADDR_SHORT;
	} else {
	__le16 short_addr = cpu_to_le16(IEEE802154_ADDR_SHORT_UNSPEC);

	n = neigh_lookup(&nd_tbl, &hdr->daddr, ldev);
	if (n) {
	llneigh = lowpan_802154_neigh(neighbour_priv(n));
	read_lock_bh(&n->lock);
	short_addr = llneigh->short_addr;
	read_unlock_bh(&n->lock);
	}

	if (llneigh &&
	lowpan_802154_is_valid_src_short_addr(short_addr)) {
	info->daddr.short_addr = short_addr;
	info->daddr.mode = IEEE802154_ADDR_SHORT;
	} else {
	info->daddr.mode = IEEE802154_ADDR_LONG;
	ieee802154_be64_to_le64(&info->daddr.extended_addr,
	daddr);
	}

	if (n)
	neigh_release(n);
	}

	if (!saddr) {
	if (lowpan_802154_is_valid_src_short_addr(wpan_dev->short_addr)) {
	info->saddr.mode = IEEE802154_ADDR_SHORT;
	info->saddr.short_addr = wpan_dev->short_addr;
	} else {
	info->saddr.mode = IEEE802154_ADDR_LONG;
	info->saddr.extended_addr = wpan_dev->extended_addr;
	}
	} else {
	info->saddr.mode = IEEE802154_ADDR_LONG;
	ieee802154_be64_to_le64(&info->saddr.extended_addr, saddr);
	}

	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_802154_dev(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) {
	skb_put_data(frag, 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);

	skb_put_data(frag, frag_hdr, frag_hdrlen);
	skb_put_data(frag, 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, u16 dgram_size,
	u16 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_802154_dev(ldev)->fragment_tag);
	lowpan_802154_dev(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);

	ldev->stats.tx_packets++;
	ldev->stats.tx_bytes += dgram_size;
	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,
	u16 dgram_size, u16 dgram_offset)
	{
	struct wpan_dev *wpan_dev = lowpan_802154_dev(ldev)->wdev->ieee802154_ptr;
	struct ieee802154_mac_cb *cb = mac_cb_init(skb);
	struct lowpan_addr_info info;

	memcpy(&info, lowpan_skb_priv(skb), sizeof(info));

	*dgram_size = skb->len;
	lowpan_header_compress(skb, ldev, &info.daddr, &info.saddr);
	/* 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;

	if (info.daddr.mode == IEEE802154_ADDR_SHORT &&
	ieee802154_is_broadcast_short_addr(info.daddr.short_addr))
	cb->ackreq = false;
	else
	cb->ackreq = wpan_dev->ackreq;

	return wpan_dev_hard_header(skb, lowpan_802154_dev(ldev)->wdev,
	&info.daddr, &info.saddr, 0);
	}

	netdev_tx_t lowpan_xmit(struct sk_buff skb, struct net_device ldev)
	{
	struct ieee802154_hdr wpan_hdr;
	int max_single, ret;
	u16 dgram_size, dgram_offset;

	pr_debug("package xmit\n");

	WARN_ON_ONCE(skb->len > IPV6_MIN_MTU);

	/* We must take a copy of the skb before we modify/replace the ipv6
	* header as the header could be used elsewhere
	*/
	if (unlikely(skb_headroom(skb) < ldev->needed_headroom \|\|
	skb_tailroom(skb) < ldev->needed_tailroom)) {
	struct sk_buff *nskb;

	nskb = skb_copy_expand(skb, ldev->needed_headroom,
	ldev->needed_tailroom, GFP_ATOMIC);
	if (likely(nskb)) {
	consume_skb(skb);
	skb = nskb;
	} else {
	kfree_skb(skb);
	return NET_XMIT_DROP;
	}
	} else {
	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_802154_dev(ldev)->wdev;
	ldev->stats.tx_packets++;
	ldev->stats.tx_bytes += dgram_size;
	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;
	}
	}