1 // SPDX-License-Identifier: GPL-2.0
2 /* Copyright (C) 2009-2020  B.A.T.M.A.N. contributors:
3  *
4  * Marek Lindner
5  */
6 
7 #include "gateway_common.h"
8 #include "main.h"
9 
10 #include <linux/atomic.h>
11 #include <linux/byteorder/generic.h>
12 #include <linux/errno.h>
13 #include <linux/kernel.h>
14 #include <linux/limits.h>
15 #include <linux/math64.h>
16 #include <linux/netdevice.h>
17 #include <linux/stddef.h>
18 #include <linux/string.h>
19 #include <uapi/linux/batadv_packet.h>
20 #include <uapi/linux/batman_adv.h>
21 
22 #include "gateway_client.h"
23 #include "log.h"
24 #include "tvlv.h"
25 
26 /**
27  * batadv_parse_throughput() - parse supplied string buffer to extract
28  *  throughput information
29  * @net_dev: the soft interface net device
30  * @buff: string buffer to parse
31  * @description: text shown when throughput string cannot be parsed
32  * @throughput: pointer holding the returned throughput information
33  *
34  * Return: false on parse error and true otherwise.
35  */
36 bool batadv_parse_throughput(struct net_device *net_dev, char *buff,
37 			     const char *description, u32 *throughput)
38 {
39 	enum batadv_bandwidth_units bw_unit_type = BATADV_BW_UNIT_KBIT;
40 	u64 lthroughput;
41 	char *tmp_ptr;
42 	int ret;
43 
44 	if (strlen(buff) > 4) {
45 		tmp_ptr = buff + strlen(buff) - 4;
46 
47 		if (strncasecmp(tmp_ptr, "mbit", 4) == 0)
48 			bw_unit_type = BATADV_BW_UNIT_MBIT;
49 
50 		if (strncasecmp(tmp_ptr, "kbit", 4) == 0 ||
51 		    bw_unit_type == BATADV_BW_UNIT_MBIT)
52 			*tmp_ptr = '\0';
53 	}
54 
55 	ret = kstrtou64(buff, 10, &lthroughput);
56 	if (ret) {
57 		batadv_err(net_dev,
58 			   "Invalid throughput speed for %s: %s\n",
59 			   description, buff);
60 		return false;
61 	}
62 
63 	switch (bw_unit_type) {
64 	case BATADV_BW_UNIT_MBIT:
65 		/* prevent overflow */
66 		if (U64_MAX / 10 < lthroughput) {
67 			batadv_err(net_dev,
68 				   "Throughput speed for %s too large: %s\n",
69 				   description, buff);
70 			return false;
71 		}
72 
73 		lthroughput *= 10;
74 		break;
75 	case BATADV_BW_UNIT_KBIT:
76 	default:
77 		lthroughput = div_u64(lthroughput, 100);
78 		break;
79 	}
80 
81 	if (lthroughput > U32_MAX) {
82 		batadv_err(net_dev,
83 			   "Throughput speed for %s too large: %s\n",
84 			   description, buff);
85 		return false;
86 	}
87 
88 	*throughput = lthroughput;
89 
90 	return true;
91 }
92 
93 /**
94  * batadv_parse_gw_bandwidth() - parse supplied string buffer to extract
95  *  download and upload bandwidth information
96  * @net_dev: the soft interface net device
97  * @buff: string buffer to parse
98  * @down: pointer holding the returned download bandwidth information
99  * @up: pointer holding the returned upload bandwidth information
100  *
101  * Return: false on parse error and true otherwise.
102  */
103 static bool batadv_parse_gw_bandwidth(struct net_device *net_dev, char *buff,
104 				      u32 *down, u32 *up)
105 {
106 	char *slash_ptr;
107 	bool ret;
108 
109 	slash_ptr = strchr(buff, '/');
110 	if (slash_ptr)
111 		*slash_ptr = 0;
112 
113 	ret = batadv_parse_throughput(net_dev, buff, "download gateway speed",
114 				      down);
115 	if (!ret)
116 		return false;
117 
118 	/* we also got some upload info */
119 	if (slash_ptr) {
120 		ret = batadv_parse_throughput(net_dev, slash_ptr + 1,
121 					      "upload gateway speed", up);
122 		if (!ret)
123 			return false;
124 	}
125 
126 	return true;
127 }
128 
129 /**
130  * batadv_gw_tvlv_container_update() - update the gw tvlv container after
131  *  gateway setting change
132  * @bat_priv: the bat priv with all the soft interface information
133  */
134 void batadv_gw_tvlv_container_update(struct batadv_priv *bat_priv)
135 {
136 	struct batadv_tvlv_gateway_data gw;
137 	u32 down, up;
138 	char gw_mode;
139 
140 	gw_mode = atomic_read(&bat_priv->gw.mode);
141 
142 	switch (gw_mode) {
143 	case BATADV_GW_MODE_OFF:
144 	case BATADV_GW_MODE_CLIENT:
145 		batadv_tvlv_container_unregister(bat_priv, BATADV_TVLV_GW, 1);
146 		break;
147 	case BATADV_GW_MODE_SERVER:
148 		down = atomic_read(&bat_priv->gw.bandwidth_down);
149 		up = atomic_read(&bat_priv->gw.bandwidth_up);
150 		gw.bandwidth_down = htonl(down);
151 		gw.bandwidth_up = htonl(up);
152 		batadv_tvlv_container_register(bat_priv, BATADV_TVLV_GW, 1,
153 					       &gw, sizeof(gw));
154 		break;
155 	}
156 }
157 
158 /**
159  * batadv_gw_bandwidth_set() - Parse and set download/upload gateway bandwidth
160  *  from supplied string buffer
161  * @net_dev: netdev struct of the soft interface
162  * @buff: the buffer containing the user data
163  * @count: number of bytes in the buffer
164  *
165  * Return: 'count' on success or a negative error code in case of failure
166  */
167 ssize_t batadv_gw_bandwidth_set(struct net_device *net_dev, char *buff,
168 				size_t count)
169 {
170 	struct batadv_priv *bat_priv = netdev_priv(net_dev);
171 	u32 down_curr;
172 	u32 up_curr;
173 	u32 down_new = 0;
174 	u32 up_new = 0;
175 	bool ret;
176 
177 	down_curr = (unsigned int)atomic_read(&bat_priv->gw.bandwidth_down);
178 	up_curr = (unsigned int)atomic_read(&bat_priv->gw.bandwidth_up);
179 
180 	ret = batadv_parse_gw_bandwidth(net_dev, buff, &down_new, &up_new);
181 	if (!ret)
182 		return -EINVAL;
183 
184 	if (!down_new)
185 		down_new = 1;
186 
187 	if (!up_new)
188 		up_new = down_new / 5;
189 
190 	if (!up_new)
191 		up_new = 1;
192 
193 	if (down_curr == down_new && up_curr == up_new)
194 		return count;
195 
196 	batadv_gw_reselect(bat_priv);
197 	batadv_info(net_dev,
198 		    "Changing gateway bandwidth from: '%u.%u/%u.%u MBit' to: '%u.%u/%u.%u MBit'\n",
199 		    down_curr / 10, down_curr % 10, up_curr / 10, up_curr % 10,
200 		    down_new / 10, down_new % 10, up_new / 10, up_new % 10);
201 
202 	atomic_set(&bat_priv->gw.bandwidth_down, down_new);
203 	atomic_set(&bat_priv->gw.bandwidth_up, up_new);
204 	batadv_gw_tvlv_container_update(bat_priv);
205 
206 	return count;
207 }
208 
209 /**
210  * batadv_gw_tvlv_ogm_handler_v1() - process incoming gateway tvlv container
211  * @bat_priv: the bat priv with all the soft interface information
212  * @orig: the orig_node of the ogm
213  * @flags: flags indicating the tvlv state (see batadv_tvlv_handler_flags)
214  * @tvlv_value: tvlv buffer containing the gateway data
215  * @tvlv_value_len: tvlv buffer length
216  */
217 static void batadv_gw_tvlv_ogm_handler_v1(struct batadv_priv *bat_priv,
218 					  struct batadv_orig_node *orig,
219 					  u8 flags,
220 					  void *tvlv_value, u16 tvlv_value_len)
221 {
222 	struct batadv_tvlv_gateway_data gateway, *gateway_ptr;
223 
224 	/* only fetch the tvlv value if the handler wasn't called via the
225 	 * CIFNOTFND flag and if there is data to fetch
226 	 */
227 	if (flags & BATADV_TVLV_HANDLER_OGM_CIFNOTFND ||
228 	    tvlv_value_len < sizeof(gateway)) {
229 		gateway.bandwidth_down = 0;
230 		gateway.bandwidth_up = 0;
231 	} else {
232 		gateway_ptr = tvlv_value;
233 		gateway.bandwidth_down = gateway_ptr->bandwidth_down;
234 		gateway.bandwidth_up = gateway_ptr->bandwidth_up;
235 		if (gateway.bandwidth_down == 0 ||
236 		    gateway.bandwidth_up == 0) {
237 			gateway.bandwidth_down = 0;
238 			gateway.bandwidth_up = 0;
239 		}
240 	}
241 
242 	batadv_gw_node_update(bat_priv, orig, &gateway);
243 
244 	/* restart gateway selection */
245 	if (gateway.bandwidth_down != 0 &&
246 	    atomic_read(&bat_priv->gw.mode) == BATADV_GW_MODE_CLIENT)
247 		batadv_gw_check_election(bat_priv, orig);
248 }
249 
250 /**
251  * batadv_gw_init() - initialise the gateway handling internals
252  * @bat_priv: the bat priv with all the soft interface information
253  */
254 void batadv_gw_init(struct batadv_priv *bat_priv)
255 {
256 	if (bat_priv->algo_ops->gw.init_sel_class)
257 		bat_priv->algo_ops->gw.init_sel_class(bat_priv);
258 	else
259 		atomic_set(&bat_priv->gw.sel_class, 1);
260 
261 	batadv_tvlv_handler_register(bat_priv, batadv_gw_tvlv_ogm_handler_v1,
262 				     NULL, BATADV_TVLV_GW, 1,
263 				     BATADV_TVLV_HANDLER_OGM_CIFNOTFND);
264 }
265 
266 /**
267  * batadv_gw_free() - free the gateway handling internals
268  * @bat_priv: the bat priv with all the soft interface information
269  */
270 void batadv_gw_free(struct batadv_priv *bat_priv)
271 {
272 	batadv_tvlv_container_unregister(bat_priv, BATADV_TVLV_GW, 1);
273 	batadv_tvlv_handler_unregister(bat_priv, BATADV_TVLV_GW, 1);
274 }
275