1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * RTL8188EU monitor interface
4 *
5 * Copyright (C) 2015 Jakub Sitnicki
6 */
7
8 #include <linux/ieee80211.h>
9 #include <linux/netdevice.h>
10 #include <net/cfg80211.h>
11
12 #include <drv_types.h>
13 #include <rtw_recv.h>
14 #include <rtw_xmit.h>
15 #include <mon.h>
16
17 /**
18 * unprotect_frame() - unset Protected flag and strip off IV and ICV/MIC
19 */
unprotect_frame(struct sk_buff * skb,int iv_len,int icv_len)20 static void unprotect_frame(struct sk_buff *skb, int iv_len, int icv_len)
21 {
22 struct ieee80211_hdr *hdr;
23 int hdr_len;
24
25 hdr = (struct ieee80211_hdr *)skb->data;
26 hdr_len = ieee80211_hdrlen(hdr->frame_control);
27
28 if (skb->len < hdr_len + iv_len + icv_len)
29 return;
30 if (!ieee80211_has_protected(hdr->frame_control))
31 return;
32
33 hdr->frame_control &= ~cpu_to_le16(IEEE80211_FCTL_PROTECTED);
34
35 memmove(skb->data + iv_len, skb->data, hdr_len);
36 skb_pull(skb, iv_len);
37 skb_trim(skb, skb->len - icv_len);
38 }
39
mon_recv_decrypted(struct net_device * dev,const u8 * data,int data_len,int iv_len,int icv_len)40 static void mon_recv_decrypted(struct net_device *dev, const u8 *data,
41 int data_len, int iv_len, int icv_len)
42 {
43 struct sk_buff *skb;
44
45 skb = netdev_alloc_skb(dev, data_len);
46 if (!skb)
47 return;
48 skb_put_data(skb, data, data_len);
49
50 /*
51 * Frame data is not encrypted. Strip off protection so
52 * userspace doesn't think that it is.
53 */
54 unprotect_frame(skb, iv_len, icv_len);
55
56 skb->ip_summed = CHECKSUM_UNNECESSARY;
57 skb->protocol = eth_type_trans(skb, dev);
58 netif_rx(skb);
59 }
60
mon_recv_encrypted(struct net_device * dev,const u8 * data,int data_len)61 static void mon_recv_encrypted(struct net_device *dev, const u8 *data,
62 int data_len)
63 {
64 if (net_ratelimit())
65 netdev_info(dev, "Encrypted packets are not supported");
66 }
67
68 /**
69 * rtl88eu_mon_recv_hook() - forward received frame to the monitor interface
70 *
71 * Assumes that the frame contains an IV and an ICV/MIC, and that
72 * encrypt field in frame->attrib have been set accordingly.
73 */
rtl88eu_mon_recv_hook(struct net_device * dev,struct recv_frame * frame)74 void rtl88eu_mon_recv_hook(struct net_device *dev, struct recv_frame *frame)
75 {
76 struct rx_pkt_attrib *attr;
77 int iv_len, icv_len;
78 int data_len;
79 u8 *data;
80
81 if (!dev || !frame)
82 return;
83 if (!netif_running(dev))
84 return;
85
86 attr = &frame->attrib;
87 data = frame->pkt->data;
88 data_len = frame->pkt->len;
89
90 /* Broadcast and multicast frames don't have attr->{iv,icv}_len set */
91 SET_ICE_IV_LEN(iv_len, icv_len, attr->encrypt);
92
93 if (attr->bdecrypted)
94 mon_recv_decrypted(dev, data, data_len, iv_len, icv_len);
95 else
96 mon_recv_encrypted(dev, data, data_len);
97 }
98
99 /**
100 * rtl88eu_mon_xmit_hook() - forward trasmitted frame to the monitor interface
101 *
102 * Assumes that:
103 * - frame header contains an IV and frame->attrib.iv_len is set accordingly,
104 * - data is not encrypted and ICV/MIC has not been appended yet.
105 */
rtl88eu_mon_xmit_hook(struct net_device * dev,struct xmit_frame * frame,uint frag_len)106 void rtl88eu_mon_xmit_hook(struct net_device *dev, struct xmit_frame *frame,
107 uint frag_len)
108 {
109 struct pkt_attrib *attr;
110 u8 *data;
111 int i, offset;
112
113 if (!dev || !frame)
114 return;
115 if (!netif_running(dev))
116 return;
117
118 attr = &frame->attrib;
119
120 offset = TXDESC_SIZE + frame->pkt_offset * PACKET_OFFSET_SZ;
121 data = frame->buf_addr + offset;
122
123 for (i = 0; i < attr->nr_frags - 1; i++) {
124 mon_recv_decrypted(dev, data, frag_len, attr->iv_len, 0);
125 data += frag_len;
126 data = (u8 *)round_up((size_t)data, 4);
127 }
128 /* Last fragment has different length */
129 mon_recv_decrypted(dev, data, attr->last_txcmdsz, attr->iv_len, 0);
130 }
131
mon_xmit(struct sk_buff * skb,struct net_device * dev)132 static netdev_tx_t mon_xmit(struct sk_buff *skb, struct net_device *dev)
133 {
134 dev_kfree_skb(skb);
135 return NETDEV_TX_OK;
136 }
137
138 static const struct net_device_ops mon_netdev_ops = {
139 .ndo_start_xmit = mon_xmit,
140 .ndo_set_mac_address = eth_mac_addr,
141 .ndo_validate_addr = eth_validate_addr,
142 };
143
mon_setup(struct net_device * dev)144 static void mon_setup(struct net_device *dev)
145 {
146 dev->netdev_ops = &mon_netdev_ops;
147 dev->needs_free_netdev = true;
148 ether_setup(dev);
149 dev->priv_flags |= IFF_NO_QUEUE;
150 dev->type = ARPHRD_IEEE80211;
151 /*
152 * Use a locally administered address (IEEE 802)
153 * XXX: Copied from mac80211_hwsim driver. Revisit.
154 */
155 eth_zero_addr(dev->dev_addr);
156 dev->dev_addr[0] = 0x12;
157 }
158
rtl88eu_mon_init(void)159 struct net_device *rtl88eu_mon_init(void)
160 {
161 struct net_device *dev;
162 int err;
163
164 dev = alloc_netdev(0, "mon%d", NET_NAME_UNKNOWN, mon_setup);
165 if (!dev)
166 goto fail;
167
168 err = register_netdev(dev);
169 if (err < 0)
170 goto fail_free_dev;
171
172 return dev;
173
174 fail_free_dev:
175 free_netdev(dev);
176 fail:
177 return NULL;
178 }
179
rtl88eu_mon_deinit(struct net_device * dev)180 void rtl88eu_mon_deinit(struct net_device *dev)
181 {
182 if (!dev)
183 return;
184
185 unregister_netdev(dev);
186 }
187