diff options
Diffstat (limited to 'drivers/uwb/wlp/txrx.c')
| -rw-r--r-- | drivers/uwb/wlp/txrx.c | 374 |
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); |