Linux Kernel  3.7.1
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rx.c
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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 {
25 } __packed;
26 
27 struct rfc1042hdr {
33 } __packed;
34 
35 struct rxpackethdr {
38 } __packed;
39 
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 
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 
69 
70  BUG_ON(!skb);
71 
72  skb->ip_summed = CHECKSUM_NONE;
73 
74  if (priv->wdev->iftype == NL80211_IFTYPE_MONITOR)
75  return process_rxed_802_11_packet(priv, skb);
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 = 0;
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  lbs_deb_leave_args(LBS_DEB_RX, "ret %d", ret);
160  return ret;
161 }
163 
171 static u8 convert_mv_rate_to_radiotap(u8 rate)
172 {
173  switch (rate) {
174  case 0: /* 1 Mbps */
175  return 2;
176  case 1: /* 2 Mbps */
177  return 4;
178  case 2: /* 5.5 Mbps */
179  return 11;
180  case 3: /* 11 Mbps */
181  return 22;
182  /* case 4: reserved */
183  case 5: /* 6 Mbps */
184  return 12;
185  case 6: /* 9 Mbps */
186  return 18;
187  case 7: /* 12 Mbps */
188  return 24;
189  case 8: /* 18 Mbps */
190  return 36;
191  case 9: /* 24 Mbps */
192  return 48;
193  case 10: /* 36 Mbps */
194  return 72;
195  case 11: /* 48 Mbps */
196  return 96;
197  case 12: /* 54 Mbps */
198  return 108;
199  }
200  pr_alert("Invalid Marvell WLAN rate %i\n", rate);
201  return 0;
202 }
203 
212 static int process_rxed_802_11_packet(struct lbs_private *priv,
213  struct sk_buff *skb)
214 {
215  int ret = 0;
216  struct net_device *dev = priv->dev;
217  struct rx80211packethdr *p_rx_pkt;
218  struct rxpd *prxpd;
219  struct rx_radiotap_hdr radiotap_hdr;
220  struct rx_radiotap_hdr *pradiotap_hdr;
221 
223 
224  p_rx_pkt = (struct rx80211packethdr *) skb->data;
225  prxpd = &p_rx_pkt->rx_pd;
226 
227  /* lbs_deb_hex(LBS_DEB_RX, "RX Data: Before chop rxpd", skb->data, min(skb->len, 100)); */
228 
229  if (skb->len < (ETH_HLEN + 8 + sizeof(struct rxpd))) {
230  lbs_deb_rx("rx err: frame received with bad length\n");
231  dev->stats.rx_length_errors++;
232  ret = -EINVAL;
233  kfree_skb(skb);
234  goto done;
235  }
236 
237  lbs_deb_rx("rx data: skb->len-sizeof(RxPd) = %d-%zd = %zd\n",
238  skb->len, sizeof(struct rxpd), skb->len - sizeof(struct rxpd));
239 
240  /* create the exported radio header */
241 
242  /* radiotap header */
243  memset(&radiotap_hdr, 0, sizeof(radiotap_hdr));
244  /* XXX must check radiotap_hdr.hdr.it_pad for pad */
245  radiotap_hdr.hdr.it_len = cpu_to_le16 (sizeof(struct rx_radiotap_hdr));
246  radiotap_hdr.hdr.it_present = cpu_to_le32 (RX_RADIOTAP_PRESENT);
247  radiotap_hdr.rate = convert_mv_rate_to_radiotap(prxpd->rx_rate);
248  /* XXX must check no carryout */
249  radiotap_hdr.antsignal = prxpd->snr + prxpd->nf;
250 
251  /* chop the rxpd */
252  skb_pull(skb, sizeof(struct rxpd));
253 
254  /* add space for the new radio header */
255  if ((skb_headroom(skb) < sizeof(struct rx_radiotap_hdr)) &&
256  pskb_expand_head(skb, sizeof(struct rx_radiotap_hdr), 0, GFP_ATOMIC)) {
257  netdev_alert(dev, "%s: couldn't pskb_expand_head\n", __func__);
258  ret = -ENOMEM;
259  kfree_skb(skb);
260  goto done;
261  }
262 
263  pradiotap_hdr = (void *)skb_push(skb, sizeof(struct rx_radiotap_hdr));
264  memcpy(pradiotap_hdr, &radiotap_hdr, sizeof(struct rx_radiotap_hdr));
265 
267 
268  lbs_deb_rx("rx data: size of actual packet %d\n", skb->len);
269  dev->stats.rx_bytes += skb->len;
270  dev->stats.rx_packets++;
271 
272  skb->protocol = eth_type_trans(skb, priv->dev);
273 
274  if (in_interrupt())
275  netif_rx(skb);
276  else
277  netif_rx_ni(skb);
278 
279  ret = 0;
280 
281 done:
282  lbs_deb_leave_args(LBS_DEB_RX, "ret %d", ret);
283  return ret;
284 }