1 files changed, 309 insertions, 0 deletions
diff --git a/net/ieee802154/6lowpan/tx.c b/net/ieee802154/6lowpan/tx.c
new file mode 100644
index 000000000..0c07662b4
--- /dev/null
+++ b/net/ieee802154/6lowpan/tx.c
@@ -0,0 +1,309 @@
+// SPDX-License-Identifier: GPL-2.0-only
+
+#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;
+
+	if (!daddr)
+		return -EINVAL;
+
+	/* 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;
+	}
+}