uwb: add the WiMedia LLC Protocol stack

Add the generic code for the WiMedia Logical Link Control Protocol (WLP).

This has been split into several patches for easier review.

core (this patch):
  - everything else

messages:
  - WLP message construction/decode

wss:
  - Wireless Service Set support

build-system:
  - Kconfig and Kbuild files

Signed-off-by: David Vrabel <david.vrabel@csr.com>

1 files changed, 374 insertions, 0 deletions

diff --git a/drivers/uwb/wlp/txrx.c b/drivers/uwb/wlp/txrx.c
new file mode 100644
index 00000000000..c701bd1a288
--- /dev/null
+++ b/drivers/uwb/wlp/txrx.c
@@ -0,0 +1,374 @@
+/*
+ * WiMedia Logical Link Control Protocol (WLP)
+ * Message exchange infrastructure
+ *
+ * Copyright (C) 2007 Intel Corporation
+ * Reinette Chatre <reinette.chatre@intel.com>
+ *
+ * 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.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
+ * 02110-1301, USA.
+ *
+ *
+ * FIXME: Docs
+ *
+ */
+
+#include <linux/etherdevice.h>
+#include <linux/wlp.h>
+#define D_LOCAL 5
+#include <linux/uwb/debug.h>
+#include "wlp-internal.h"
+
+
+/**
+ * Direct incoming association msg to correct parsing routine
+ *
+ * We only expect D1, E1, C1, C3 messages as new. All other incoming
+ * association messages should form part of an established session that is
+ * handled elsewhere.
+ * The handling of these messages often require calling sleeping functions
+ * - this cannot be done in interrupt context. We use the kernel's
+ * workqueue to handle these messages.
+ */
+static
+void wlp_direct_assoc_frame(struct wlp *wlp, struct sk_buff *skb,
+			   struct uwb_dev_addr *src)
+{
+	struct device *dev = &wlp->rc->uwb_dev.dev;
+	struct wlp_frame_assoc *assoc = (void *) skb->data;
+	struct wlp_assoc_frame_ctx *frame_ctx;
+	d_fnstart(5, dev, "wlp %p, skb %p\n", wlp, skb);
+	frame_ctx = kmalloc(sizeof(*frame_ctx), GFP_ATOMIC);
+	if (frame_ctx == NULL) {
+		dev_err(dev, "WLP: Unable to allocate memory for association "
+			"frame handling.\n");
+		kfree_skb(skb);
+		goto out;
+	}
+	frame_ctx->wlp = wlp;
+	frame_ctx->skb = skb;
+	frame_ctx->src = *src;
+	switch (assoc->type) {
+	case WLP_ASSOC_D1:
+		d_printf(5, dev, "Received a D1 frame.\n");
+		INIT_WORK(&frame_ctx->ws, wlp_handle_d1_frame);
+		schedule_work(&frame_ctx->ws);
+		break;
+	case WLP_ASSOC_E1:
+		d_printf(5, dev, "Received a E1 frame. FIXME?\n");
+		kfree_skb(skb); /* Temporary until we handle it */
+		kfree(frame_ctx); /* Temporary until we handle it */
+		break;
+	case WLP_ASSOC_C1:
+		d_printf(5, dev, "Received a C1 frame.\n");
+		INIT_WORK(&frame_ctx->ws, wlp_handle_c1_frame);
+		schedule_work(&frame_ctx->ws);
+		break;
+	case WLP_ASSOC_C3:
+		d_printf(5, dev, "Received a C3 frame.\n");
+		INIT_WORK(&frame_ctx->ws, wlp_handle_c3_frame);
+		schedule_work(&frame_ctx->ws);
+		break;
+	default:
+		dev_err(dev, "Received unexpected association frame. "
+			"Type = %d \n", assoc->type);
+		kfree_skb(skb);
+		kfree(frame_ctx);
+		break;
+	}
+out:
+	d_fnend(5, dev, "wlp %p\n", wlp);
+}
+
+/**
+ * Process incoming association frame
+ *
+ * Although it could be possible to deal with some incoming association
+ * messages without creating a new session we are keeping things simple. We
+ * do not accept new association messages if there is a session in progress
+ * and the messages do not belong to that session.
+ *
+ * If an association message arrives that causes the creation of a session
+ * (WLP_ASSOC_E1) while we are in the process of creating a session then we
+ * rely on the neighbor mutex to protect the data. That is, the new session
+ * will not be started until the previous is completed.
+ */
+static
+void wlp_receive_assoc_frame(struct wlp *wlp, struct sk_buff *skb,
+			     struct uwb_dev_addr *src)
+{
+	struct device *dev = &wlp->rc->uwb_dev.dev;
+	struct wlp_frame_assoc *assoc = (void *) skb->data;
+	struct wlp_session *session = wlp->session;
+	u8 version;
+	d_fnstart(5, dev, "wlp %p, skb %p\n", wlp, skb);
+
+	if (wlp_get_version(wlp, &assoc->version, &version,
+			    sizeof(assoc->version)) < 0)
+		goto error;
+	if (version != WLP_VERSION) {
+		dev_err(dev, "Unsupported WLP version in association "
+			"message.\n");
+		goto error;
+	}
+	if (session != NULL) {
+		/* Function that created this session is still holding the
+		 * &wlp->mutex to protect this session. */
+		if (assoc->type == session->exp_message ||
+		    assoc->type == WLP_ASSOC_F0) {
+			if (!memcmp(&session->neighbor_addr, src,
+				   sizeof(*src))) {
+				session->data = skb;
+				(session->cb)(wlp);
+			} else {
+				dev_err(dev, "Received expected message from "
+					"unexpected source.  Expected message "
+					"%d or F0 from %02x:%02x, but received "
+					"it from %02x:%02x. Dropping.\n",
+					session->exp_message,
+					session->neighbor_addr.data[1],
+					session->neighbor_addr.data[0],
+					src->data[1], src->data[0]);
+				goto error;
+			}
+		} else {
+			dev_err(dev, "Association already in progress. "
+				"Dropping.\n");
+			goto error;
+		}
+	} else {
+		wlp_direct_assoc_frame(wlp, skb, src);
+	}
+	d_fnend(5, dev, "wlp %p\n", wlp);
+	return;
+error:
+	kfree_skb(skb);
+	d_fnend(5, dev, "wlp %p\n", wlp);
+}
+
+/**
+ * Verify incoming frame is from connected neighbor, prep to pass to WLP client
+ *
+ * Verification proceeds according to WLP 0.99 [7.3.1]. The source address
+ * is used to determine which neighbor is sending the frame and the WSS tag
+ * is used to know to which WSS the frame belongs (we only support one WSS
+ * so this test is straight forward).
+ * With the WSS found we need to ensure that we are connected before
+ * allowing the exchange of data frames.
+ */
+static
+int wlp_verify_prep_rx_frame(struct wlp *wlp, struct sk_buff *skb,
+			     struct uwb_dev_addr *src)
+{
+	struct device *dev = &wlp->rc->uwb_dev.dev;
+	int result = -EINVAL;
+	struct wlp_eda_node eda_entry;
+	struct wlp_frame_std_abbrv_hdr *hdr = (void *) skb->data;
+
+	d_fnstart(6, dev, "wlp %p, skb %p \n", wlp, skb);
+	/*verify*/
+	result = wlp_copy_eda_node(&wlp->eda, src, &eda_entry);
+	if (result < 0) {
+		if (printk_ratelimit())
+			dev_err(dev, "WLP: Incoming frame is from unknown "
+				"neighbor %02x:%02x.\n", src->data[1],
+				src->data[0]);
+		goto out;
+	}
+	if (hdr->tag != eda_entry.tag) {
+		if (printk_ratelimit())
+			dev_err(dev, "WLP: Tag of incoming frame from "
+				"%02x:%02x does not match expected tag. "
+				"Received 0x%02x, expected 0x%02x. \n",
+				src->data[1], src->data[0], hdr->tag,
+				eda_entry.tag);
+		result = -EINVAL;
+		goto out;
+	}
+	if (eda_entry.state != WLP_WSS_CONNECTED) {
+		if (printk_ratelimit())
+			dev_err(dev, "WLP: Incoming frame from "
+				"%02x:%02x does is not from connected WSS.\n",
+				src->data[1], src->data[0]);
+		result = -EINVAL;
+		goto out;
+	}
+	/*prep*/
+	skb_pull(skb, sizeof(*hdr));
+out:
+	d_fnend(6, dev, "wlp %p, skb %p, result = %d \n", wlp, skb, result);
+	return result;
+}
+
+/**
+ * Receive a WLP frame from device
+ *
+ * @returns: 1 if calling function should free the skb
+ *           0 if it successfully handled skb and freed it
+ *           0 if error occured, will free skb in this case
+ */
+int wlp_receive_frame(struct device *dev, struct wlp *wlp, struct sk_buff *skb,
+		      struct uwb_dev_addr *src)
+{
+	unsigned len = skb->len;
+	void *ptr = skb->data;
+	struct wlp_frame_hdr *hdr;
+	int result = 0;
+
+	d_fnstart(6, dev, "skb (%p), len (%u)\n", skb, len);
+	if (len < sizeof(*hdr)) {
+		dev_err(dev, "Not enough data to parse WLP header.\n");
+		result = -EINVAL;
+		goto out;
+	}
+	hdr = ptr;
+	d_dump(6, dev, hdr, sizeof(*hdr));
+	if (le16_to_cpu(hdr->mux_hdr) != WLP_PROTOCOL_ID) {
+		dev_err(dev, "Not a WLP frame type.\n");
+		result = -EINVAL;
+		goto out;
+	}
+	switch (hdr->type) {
+	case WLP_FRAME_STANDARD:
+		if (len < sizeof(struct wlp_frame_std_abbrv_hdr)) {
+			dev_err(dev, "Not enough data to parse Standard "
+				"WLP header.\n");
+			goto out;
+		}
+		result = wlp_verify_prep_rx_frame(wlp, skb, src);
+		if (result < 0) {
+			if (printk_ratelimit())
+				dev_err(dev, "WLP: Verification of frame "
+					"from neighbor %02x:%02x failed.\n",
+					src->data[1], src->data[0]);
+			goto out;
+		}
+		result = 1;
+		break;
+	case WLP_FRAME_ABBREVIATED:
+		dev_err(dev, "Abbreviated frame received. FIXME?\n");
+		kfree_skb(skb);
+		break;
+	case WLP_FRAME_CONTROL:
+		dev_err(dev, "Control frame received. FIXME?\n");
+		kfree_skb(skb);
+		break;
+	case WLP_FRAME_ASSOCIATION:
+		if (len < sizeof(struct wlp_frame_assoc)) {
+			dev_err(dev, "Not enough data to parse Association "
+				"WLP header.\n");
+			goto out;
+		}
+		d_printf(5, dev, "Association frame received.\n");
+		wlp_receive_assoc_frame(wlp, skb, src);
+		break;
+	default:
+		dev_err(dev, "Invalid frame received.\n");
+		result = -EINVAL;
+		break;
+	}
+out:
+	if (result < 0) {
+		kfree_skb(skb);
+		result = 0;
+	}
+	d_fnend(6, dev, "skb (%p)\n", skb);
+	return result;
+}
+EXPORT_SYMBOL_GPL(wlp_receive_frame);
+
+
+/**
+ * Verify frame from network stack, prepare for further transmission
+ *
+ * @skb:   the socket buffer that needs to be prepared for transmission (it
+ *         is in need of a WLP header). If this is a broadcast frame we take
+ *         over the entire transmission.
+ *         If it is a unicast the WSS connection should already be established
+ *         and transmission will be done by the calling function.
+ * @dst:   On return this will contain the device address to which the
+ *         frame is destined.
+ * @returns: 0 on success no tx : WLP header sucessfully applied to skb buffer,
+ *                                calling function can proceed with tx
+ *           1 on success with tx : WLP will take over transmission of this
+ *                                  frame
+ *           <0 on error
+ *
+ * The network stack (WLP client) is attempting to transmit a frame. We can
+ * only transmit data if a local WSS is at least active (connection will be
+ * done here if this is a broadcast frame and neighbor also has the WSS
+ * active).
+ *
+ * The frame can be either broadcast or unicast. Broadcast in a WSS is
+ * supported via multicast, but we don't support multicast yet (until
+ * devices start to support MAB IEs). If a broadcast frame needs to be
+ * transmitted it is treated as a unicast frame to each neighbor. In this
+ * case the WLP takes over transmission of the skb and returns 1
+ * to the caller to indicate so. Also, in this case, if a neighbor has the
+ * same WSS activated but is not connected then the WSS connection will be
+ * done at this time. The neighbor's virtual address will be learned at
+ * this time.
+ *
+ * The destination address in a unicast frame is the virtual address of the
+ * neighbor. This address only becomes known when a WSS connection is
+ * established. We thus rely on a broadcast frame to trigger the setup of
+ * WSS connections to all neighbors before we are able to send unicast
+ * frames to them. This seems reasonable as IP would usually use ARP first
+ * before any unicast frames are sent.
+ *
+ * If we are already connected to the neighbor (neighbor's virtual address
+ * is known) we just prepare the WLP header and the caller will continue to
+ * send the frame.
+ *
+ * A failure in this function usually indicates something that cannot be
+ * fixed automatically. So, if this function fails (@return < 0) the calling
+ * function should not retry to send the frame as it will very likely keep
+ * failing.
+ *
+ */
+int wlp_prepare_tx_frame(struct device *dev, struct wlp *wlp,
+			 struct sk_buff *skb, struct uwb_dev_addr *dst)
+{
+	int result = -EINVAL;
+	struct ethhdr *eth_hdr = (void *) skb->data;
+
+	d_fnstart(6, dev, "wlp (%p), skb (%p) \n", wlp, skb);
+	if (is_broadcast_ether_addr(eth_hdr->h_dest)) {
+		d_printf(6, dev, "WLP: handling broadcast frame. \n");
+		result = wlp_eda_for_each(&wlp->eda, wlp_wss_send_copy, skb);
+		if (result < 0) {
+			if (printk_ratelimit())
+				dev_err(dev, "Unable to handle broadcast "
+					"frame from WLP client.\n");
+			goto out;
+		}
+		dev_kfree_skb_irq(skb);
+		result = 1;
+		/* Frame will be transmitted by WLP. */
+	} else {
+		d_printf(6, dev, "WLP: handling unicast frame. \n");
+		result = wlp_eda_for_virtual(&wlp->eda, eth_hdr->h_dest, dst,
+					     wlp_wss_prep_hdr, skb);
+		if (unlikely(result < 0)) {
+			if (printk_ratelimit())
+				dev_err(dev, "Unable to prepare "
+					"skb for transmission. \n");
+			goto out;
+		}
+	}
+out:
+	d_fnend(6, dev, "wlp (%p), skb (%p). result = %d \n", wlp, skb, result);
+	return result;
+}
+EXPORT_SYMBOL_GPL(wlp_prepare_tx_frame);