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