/*
* 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/slab.h>
#include <linux/wlp.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;
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);
return;
}
frame_ctx->wlp = wlp;
frame_ctx->skb = skb;
frame_ctx->src = *src;
switch (assoc->type) {
case WLP_ASSOC_D1:
INIT_WORK(&frame_ctx->ws, wlp_handle_d1_frame);
schedule_work(&frame_ctx->ws);
break;
case WLP_ASSOC_E1:
kfree_skb(skb); /* Temporary until we handle it */
kfree(frame_ctx); /* Temporary until we handle it */
break;
case WLP_ASSOC_C1:
INIT_WORK(&frame_ctx->ws, wlp_handle_c1_frame);
schedule_work(&frame_ctx->ws);
break;
case WLP_ASSOC_C3:
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;
}
}
/*
* 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;
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);
}
return;
error:
kfree_skb(skb);
}
/*
* 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;
/*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:
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;
if (len < sizeof(*hdr)) {
dev_err(dev, "Not enough data to parse WLP header.\n");
result = -EINVAL;
goto out;
}
hdr = ptr;
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;
}
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;
}
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 successfully 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;
if (is_multicast_ether_addr(eth_hdr->h_dest)) {
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 {
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:
return result;
}
EXPORT_SYMBOL_GPL(wlp_prepare_tx_frame);
