1 /*
2  * This file contains the handling of RX in wlan driver.
3  */
4 
5 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
6 
7 #include <linux/etherdevice.h>
8 #include <linux/hardirq.h>
9 #include <linux/slab.h>
10 #include <linux/types.h>
11 #include <linux/export.h>
12 #include <net/cfg80211.h>
13 
14 #include "defs.h"
15 #include "host.h"
16 #include "radiotap.h"
17 #include "decl.h"
18 #include "dev.h"
19 #include "mesh.h"
20 
21 struct eth803hdr {
22 	u8 dest_addr[6];
23 	u8 src_addr[6];
24 	u16 h803_len;
25 } __packed;
26 
27 struct rfc1042hdr {
28 	u8 llc_dsap;
29 	u8 llc_ssap;
30 	u8 llc_ctrl;
31 	u8 snap_oui[3];
32 	u16 snap_type;
33 } __packed;
34 
35 struct rxpackethdr {
36 	struct eth803hdr eth803_hdr;
37 	struct rfc1042hdr rfc1042_hdr;
38 } __packed;
39 
40 struct rx80211packethdr {
41 	struct rxpd rx_pd;
42 	void *eth80211_hdr;
43 } __packed;
44 
45 static int process_rxed_802_11_packet(struct lbs_private *priv,
46 	struct sk_buff *skb);
47 
48 /**
49  * lbs_process_rxed_packet - processes received packet and forwards it
50  * to kernel/upper layer
51  *
52  * @priv:	A pointer to &struct lbs_private
53  * @skb:	A pointer to skb which includes the received packet
54  * returns:	0 or -1
55  */
56 int lbs_process_rxed_packet(struct lbs_private *priv, struct sk_buff *skb)
57 {
58 	int ret = 0;
59 	struct net_device *dev = priv->dev;
60 	struct rxpackethdr *p_rx_pkt;
61 	struct rxpd *p_rx_pd;
62 	int hdrchop;
63 	struct ethhdr *p_ethhdr;
64 	static const u8 rfc1042_eth_hdr[] = {
65 		0xaa, 0xaa, 0x03, 0x00, 0x00, 0x00
66 	};
67 
68 	BUG_ON(!skb);
69 
70 	skb->ip_summed = CHECKSUM_NONE;
71 
72 	if (priv->wdev->iftype == NL80211_IFTYPE_MONITOR) {
73 		ret = process_rxed_802_11_packet(priv, skb);
74 		goto done;
75 	}
76 
77 	p_rx_pd = (struct rxpd *) skb->data;
78 	p_rx_pkt = (struct rxpackethdr *) ((u8 *)p_rx_pd +
79 		le32_to_cpu(p_rx_pd->pkt_ptr));
80 
81 	dev = lbs_mesh_set_dev(priv, dev, p_rx_pd);
82 
83 	lbs_deb_hex(LBS_DEB_RX, "RX Data: Before chop rxpd", skb->data,
84 		 min_t(unsigned int, skb->len, 100));
85 
86 	if (skb->len < (ETH_HLEN + 8 + sizeof(struct rxpd))) {
87 		lbs_deb_rx("rx err: frame received with bad length\n");
88 		dev->stats.rx_length_errors++;
89 		ret = -EINVAL;
90 		dev_kfree_skb(skb);
91 		goto done;
92 	}
93 
94 	lbs_deb_rx("rx data: skb->len - pkt_ptr = %d-%zd = %zd\n",
95 		skb->len, (size_t)le32_to_cpu(p_rx_pd->pkt_ptr),
96 		skb->len - (size_t)le32_to_cpu(p_rx_pd->pkt_ptr));
97 
98 	lbs_deb_hex(LBS_DEB_RX, "RX Data: Dest", p_rx_pkt->eth803_hdr.dest_addr,
99 		sizeof(p_rx_pkt->eth803_hdr.dest_addr));
100 	lbs_deb_hex(LBS_DEB_RX, "RX Data: Src", p_rx_pkt->eth803_hdr.src_addr,
101 		sizeof(p_rx_pkt->eth803_hdr.src_addr));
102 
103 	if (memcmp(&p_rx_pkt->rfc1042_hdr,
104 		   rfc1042_eth_hdr, sizeof(rfc1042_eth_hdr)) == 0) {
105 		/*
106 		 *  Replace the 803 header and rfc1042 header (llc/snap) with an
107 		 *    EthernetII header, keep the src/dst and snap_type (ethertype)
108 		 *
109 		 *  The firmware only passes up SNAP frames converting
110 		 *    all RX Data from 802.11 to 802.2/LLC/SNAP frames.
111 		 *
112 		 *  To create the Ethernet II, just move the src, dst address right
113 		 *    before the snap_type.
114 		 */
115 		p_ethhdr = (struct ethhdr *)
116 		    ((u8 *) &p_rx_pkt->eth803_hdr
117 		     + sizeof(p_rx_pkt->eth803_hdr) + sizeof(p_rx_pkt->rfc1042_hdr)
118 		     - sizeof(p_rx_pkt->eth803_hdr.dest_addr)
119 		     - sizeof(p_rx_pkt->eth803_hdr.src_addr)
120 		     - sizeof(p_rx_pkt->rfc1042_hdr.snap_type));
121 
122 		memcpy(p_ethhdr->h_source, p_rx_pkt->eth803_hdr.src_addr,
123 		       sizeof(p_ethhdr->h_source));
124 		memcpy(p_ethhdr->h_dest, p_rx_pkt->eth803_hdr.dest_addr,
125 		       sizeof(p_ethhdr->h_dest));
126 
127 		/* Chop off the rxpd + the excess memory from the 802.2/llc/snap header
128 		 *   that was removed
129 		 */
130 		hdrchop = (u8 *)p_ethhdr - (u8 *)p_rx_pd;
131 	} else {
132 		lbs_deb_hex(LBS_DEB_RX, "RX Data: LLC/SNAP",
133 			(u8 *) &p_rx_pkt->rfc1042_hdr,
134 			sizeof(p_rx_pkt->rfc1042_hdr));
135 
136 		/* Chop off the rxpd */
137 		hdrchop = (u8 *)&p_rx_pkt->eth803_hdr - (u8 *)p_rx_pd;
138 	}
139 
140 	/* Chop off the leading header bytes so the skb points to the start of
141 	 *   either the reconstructed EthII frame or the 802.2/llc/snap frame
142 	 */
143 	skb_pull(skb, hdrchop);
144 
145 	priv->cur_rate = lbs_fw_index_to_data_rate(p_rx_pd->rx_rate);
146 
147 	lbs_deb_rx("rx data: size of actual packet %d\n", skb->len);
148 	dev->stats.rx_bytes += skb->len;
149 	dev->stats.rx_packets++;
150 
151 	skb->protocol = eth_type_trans(skb, dev);
152 	if (in_interrupt())
153 		netif_rx(skb);
154 	else
155 		netif_rx_ni(skb);
156 
157 	ret = 0;
158 done:
159 	return ret;
160 }
161 EXPORT_SYMBOL_GPL(lbs_process_rxed_packet);
162 
163 /**
164  * convert_mv_rate_to_radiotap - converts Tx/Rx rates from Marvell WLAN format
165  * (see Table 2 in Section 3.1) to IEEE80211_RADIOTAP_RATE units (500 Kb/s)
166  *
167  * @rate:	Input rate
168  * returns:	Output Rate (0 if invalid)
169  */
170 static u8 convert_mv_rate_to_radiotap(u8 rate)
171 {
172 	switch (rate) {
173 	case 0:		/*   1 Mbps */
174 		return 2;
175 	case 1:		/*   2 Mbps */
176 		return 4;
177 	case 2:		/* 5.5 Mbps */
178 		return 11;
179 	case 3:		/*  11 Mbps */
180 		return 22;
181 	/* case 4: reserved */
182 	case 5:		/*   6 Mbps */
183 		return 12;
184 	case 6:		/*   9 Mbps */
185 		return 18;
186 	case 7:		/*  12 Mbps */
187 		return 24;
188 	case 8:		/*  18 Mbps */
189 		return 36;
190 	case 9:		/*  24 Mbps */
191 		return 48;
192 	case 10:		/*  36 Mbps */
193 		return 72;
194 	case 11:		/*  48 Mbps */
195 		return 96;
196 	case 12:		/*  54 Mbps */
197 		return 108;
198 	}
199 	pr_alert("Invalid Marvell WLAN rate %i\n", rate);
200 	return 0;
201 }
202 
203 /**
204  * process_rxed_802_11_packet - processes a received 802.11 packet and forwards
205  * it to kernel/upper layer
206  *
207  * @priv:	A pointer to &struct lbs_private
208  * @skb:	A pointer to skb which includes the received packet
209  * returns:	0 or -1
210  */
211 static int process_rxed_802_11_packet(struct lbs_private *priv,
212 	struct sk_buff *skb)
213 {
214 	int ret = 0;
215 	struct net_device *dev = priv->dev;
216 	struct rx80211packethdr *p_rx_pkt;
217 	struct rxpd *prxpd;
218 	struct rx_radiotap_hdr radiotap_hdr;
219 	struct rx_radiotap_hdr *pradiotap_hdr;
220 
221 	p_rx_pkt = (struct rx80211packethdr *) skb->data;
222 	prxpd = &p_rx_pkt->rx_pd;
223 
224 	/* lbs_deb_hex(LBS_DEB_RX, "RX Data: Before chop rxpd", skb->data, min(skb->len, 100)); */
225 
226 	if (skb->len < (ETH_HLEN + 8 + sizeof(struct rxpd))) {
227 		lbs_deb_rx("rx err: frame received with bad length\n");
228 		dev->stats.rx_length_errors++;
229 		ret = -EINVAL;
230 		kfree_skb(skb);
231 		goto done;
232 	}
233 
234 	lbs_deb_rx("rx data: skb->len-sizeof(RxPd) = %d-%zd = %zd\n",
235 	       skb->len, sizeof(struct rxpd), skb->len - sizeof(struct rxpd));
236 
237 	/* create the exported radio header */
238 
239 	/* radiotap header */
240 	memset(&radiotap_hdr, 0, sizeof(radiotap_hdr));
241 	/* XXX must check radiotap_hdr.hdr.it_pad for pad */
242 	radiotap_hdr.hdr.it_len = cpu_to_le16 (sizeof(struct rx_radiotap_hdr));
243 	radiotap_hdr.hdr.it_present = cpu_to_le32 (RX_RADIOTAP_PRESENT);
244 	radiotap_hdr.rate = convert_mv_rate_to_radiotap(prxpd->rx_rate);
245 	/* XXX must check no carryout */
246 	radiotap_hdr.antsignal = prxpd->snr + prxpd->nf;
247 
248 	/* chop the rxpd */
249 	skb_pull(skb, sizeof(struct rxpd));
250 
251 	/* add space for the new radio header */
252 	if ((skb_headroom(skb) < sizeof(struct rx_radiotap_hdr)) &&
253 	    pskb_expand_head(skb, sizeof(struct rx_radiotap_hdr), 0, GFP_ATOMIC)) {
254 		netdev_alert(dev, "%s: couldn't pskb_expand_head\n", __func__);
255 		ret = -ENOMEM;
256 		kfree_skb(skb);
257 		goto done;
258 	}
259 
260 	pradiotap_hdr = skb_push(skb, sizeof(struct rx_radiotap_hdr));
261 	memcpy(pradiotap_hdr, &radiotap_hdr, sizeof(struct rx_radiotap_hdr));
262 
263 	priv->cur_rate = lbs_fw_index_to_data_rate(prxpd->rx_rate);
264 
265 	lbs_deb_rx("rx data: size of actual packet %d\n", skb->len);
266 	dev->stats.rx_bytes += skb->len;
267 	dev->stats.rx_packets++;
268 
269 	skb->protocol = eth_type_trans(skb, priv->dev);
270 
271 	if (in_interrupt())
272 		netif_rx(skb);
273 	else
274 		netif_rx_ni(skb);
275 
276 	ret = 0;
277 
278 done:
279 	return ret;
280 }
281