ieee802154: 6lowpan: move transmit functionality

This patch moves all relevant transmit functionality into a separate tx.c
file. We can simple separate this functionality like we did it in mac802154.

Signed-off-by: Alexander Aring <alex.aring@gmail.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>

1 files changed, 271 insertions, 0 deletions

diff --git a/net/ieee802154/6lowpan/tx.c b/net/ieee802154/6lowpan/tx.c
new file mode 100644
index 000000000000..2349070bd534
--- /dev/null
+++ b/net/ieee802154/6lowpan/tx.c
@@ -0,0 +1,271 @@
+/* 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 "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));
+}
+
+int lowpan_header_create(struct sk_buff *skb, struct net_device *dev,
+			 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 = dev->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)
+{
+	struct net_device *real_dev = lowpan_dev_info(skb->dev)->real_dev;
+	struct sk_buff *frag;
+	int rc;
+
+	frag = alloc_skb(real_dev->hard_header_len +
+			 real_dev->needed_tailroom + size,
+			 GFP_ATOMIC);
+
+	if (likely(frag)) {
+		frag->dev = real_dev;
+		frag->priority = skb->priority;
+		skb_reserve(frag, real_dev->hard_header_len);
+		skb_reset_network_header(frag);
+		*mac_cb(frag) = *mac_cb(skb);
+
+		rc = dev_hard_header(frag, real_dev, 0, &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)
+{
+	struct sk_buff *frag;
+
+	raw_dump_inline(__func__, " fragment header", frag_hdr, frag_hdrlen);
+
+	frag = lowpan_alloc_frag(skb, frag_hdrlen + len, wpan_hdr);
+	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 *dev,
+		       const struct ieee802154_hdr *wpan_hdr)
+{
+	u16 dgram_size, dgram_offset;
+	__be16 frag_tag;
+	u8 frag_hdr[5];
+	int frag_cap, frag_len, payload_cap, rc;
+	int skb_unprocessed, skb_offset;
+
+	dgram_size = lowpan_uncompress_size(skb, &dgram_offset) -
+		     skb->mac_len;
+	frag_tag = htons(lowpan_dev_info(dev)->fragment_tag);
+	lowpan_dev_info(dev)->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));
+	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);
+		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 *dev)
+{
+	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;
+
+	lowpan_header_compress(skb, dev, ETH_P_IPV6, daddr, saddr, skb->len);
+
+	cb->type = IEEE802154_FC_TYPE_DATA;
+
+	/* prepare wpan address data */
+	sa.mode = IEEE802154_ADDR_LONG;
+	sa.pan_id = ieee802154_mlme_ops(dev)->get_pan_id(dev);
+	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 = true;
+	}
+
+	return dev_hard_header(skb, lowpan_dev_info(dev)->real_dev,
+			ETH_P_IPV6, (void *)&da, (void *)&sa, 0);
+}
+
+netdev_tx_t lowpan_xmit(struct sk_buff *skb, struct net_device *dev)
+{
+	struct ieee802154_hdr wpan_hdr;
+	int max_single, ret;
+
+	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, dev);
+	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(dev)->real_dev;
+		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, dev, &wpan_hdr);
+
+		return rc < 0 ? NET_XMIT_DROP : rc;
+	}
+}