1// SPDX-License-Identifier: GPL-2.0
  2/*
  3 * DECnet       An implementation of the DECnet protocol suite for the LINUX
  4 *              operating system.  DECnet is implemented using the  BSD Socket
  5 *              interface as the means of communication with the user level.
  6 *
  7 *              DECnet sysctl support functions
  8 *
  9 * Author:      Steve Whitehouse <SteveW@ACM.org>
 10 *
 11 *
 12 * Changes:
 13 * Steve Whitehouse - C99 changes and default device handling
 14 * Steve Whitehouse - Memory buffer settings, like the tcp ones
 15 *
 16 */
 17#include <linux/mm.h>
 18#include <linux/sysctl.h>
 19#include <linux/fs.h>
 20#include <linux/netdevice.h>
 21#include <linux/string.h>
 22#include <net/neighbour.h>
 23#include <net/dst.h>
 24#include <net/flow.h>
 25
 26#include <linux/uaccess.h>
 27
 28#include <net/dn.h>
 29#include <net/dn_dev.h>
 30#include <net/dn_route.h>
 31
 32
 33int decnet_debug_level;
 34int decnet_time_wait = 30;
 35int decnet_dn_count = 1;
 36int decnet_di_count = 3;
 37int decnet_dr_count = 3;
 38int decnet_log_martians = 1;
 39int decnet_no_fc_max_cwnd = NSP_MIN_WINDOW;
 40
 41/* Reasonable defaults, I hope, based on tcp's defaults */
 42long sysctl_decnet_mem[3] = { 768 << 3, 1024 << 3, 1536 << 3 };
 43int sysctl_decnet_wmem[3] = { 4 * 1024, 16 * 1024, 128 * 1024 };
 44int sysctl_decnet_rmem[3] = { 4 * 1024, 87380, 87380 * 2 };
 45
 46#ifdef CONFIG_SYSCTL
 47extern int decnet_dst_gc_interval;
 48static int min_decnet_time_wait[] = { 5 };
 49static int max_decnet_time_wait[] = { 600 };
 50static int min_state_count[] = { 1 };
 51static int max_state_count[] = { NSP_MAXRXTSHIFT };
 52static int min_decnet_dst_gc_interval[] = { 1 };
 53static int max_decnet_dst_gc_interval[] = { 60 };
 54static int min_decnet_no_fc_max_cwnd[] = { NSP_MIN_WINDOW };
 55static int max_decnet_no_fc_max_cwnd[] = { NSP_MAX_WINDOW };
 56static char node_name[7] = "???";
 57
 58static struct ctl_table_header *dn_table_header = NULL;
 59
 60/*
 61 * ctype.h :-)
 62 */
 63#define ISNUM(x) (((x) >= '0') && ((x) <= '9'))
 64#define ISLOWER(x) (((x) >= 'a') && ((x) <= 'z'))
 65#define ISUPPER(x) (((x) >= 'A') && ((x) <= 'Z'))
 66#define ISALPHA(x) (ISLOWER(x) || ISUPPER(x))
 67#define INVALID_END_CHAR(x) (ISNUM(x) || ISALPHA(x))
 68
 69static void strip_it(char *str)
 70{
 71	for(;;) {
 72		switch (*str) {
 73		case ' ':
 74		case '\n':
 75		case '\r':
 76		case ':':
 77			*str = 0;
 78			/* Fallthrough */
 79		case 0:
 80			return;
 81		}
 82		str++;
 83	}
 84}
 85
 86/*
 87 * Simple routine to parse an ascii DECnet address
 88 * into a network order address.
 89 */
 90static int parse_addr(__le16 *addr, char *str)
 91{
 92	__u16 area, node;
 93
 94	while(*str && !ISNUM(*str)) str++;
 95
 96	if (*str == 0)
 97		return -1;
 98
 99	area = (*str++ - '0');
100	if (ISNUM(*str)) {
101		area *= 10;
102		area += (*str++ - '0');
103	}
104
105	if (*str++ != '.')
106		return -1;
107
108	if (!ISNUM(*str))
109		return -1;
110
111	node = *str++ - '0';
112	if (ISNUM(*str)) {
113		node *= 10;
114		node += (*str++ - '0');
115	}
116	if (ISNUM(*str)) {
117		node *= 10;
118		node += (*str++ - '0');
119	}
120	if (ISNUM(*str)) {
121		node *= 10;
122		node += (*str++ - '0');
123	}
124
125	if ((node > 1023) || (area > 63))
126		return -1;
127
128	if (INVALID_END_CHAR(*str))
129		return -1;
130
131	*addr = cpu_to_le16((area << 10) | node);
132
133	return 0;
134}
135
136static int dn_node_address_handler(struct ctl_table *table, int write,
137				void __user *buffer,
138				size_t *lenp, loff_t *ppos)
139{
140	char addr[DN_ASCBUF_LEN];
141	size_t len;
142	__le16 dnaddr;
143
144	if (!*lenp || (*ppos && !write)) {
145		*lenp = 0;
146		return 0;
147	}
148
149	if (write) {
150		len = (*lenp < DN_ASCBUF_LEN) ? *lenp : (DN_ASCBUF_LEN-1);
151
152		if (copy_from_user(addr, buffer, len))
153			return -EFAULT;
154
155		addr[len] = 0;
156		strip_it(addr);
157
158		if (parse_addr(&dnaddr, addr))
159			return -EINVAL;
160
161		dn_dev_devices_off();
162
163		decnet_address = dnaddr;
164
165		dn_dev_devices_on();
166
167		*ppos += len;
168
169		return 0;
170	}
171
172	dn_addr2asc(le16_to_cpu(decnet_address), addr);
173	len = strlen(addr);
174	addr[len++] = '\n';
175
176	if (len > *lenp) len = *lenp;
177
178	if (copy_to_user(buffer, addr, len))
179		return -EFAULT;
180
181	*lenp = len;
182	*ppos += len;
183
184	return 0;
185}
186
187static int dn_def_dev_handler(struct ctl_table *table, int write,
188				void __user *buffer,
189				size_t *lenp, loff_t *ppos)
190{
191	size_t len;
192	struct net_device *dev;
193	char devname[17];
194
195	if (!*lenp || (*ppos && !write)) {
196		*lenp = 0;
197		return 0;
198	}
199
200	if (write) {
201		if (*lenp > 16)
202			return -E2BIG;
203
204		if (copy_from_user(devname, buffer, *lenp))
205			return -EFAULT;
206
207		devname[*lenp] = 0;
208		strip_it(devname);
209
210		dev = dev_get_by_name(&init_net, devname);
211		if (dev == NULL)
212			return -ENODEV;
213
214		if (dev->dn_ptr == NULL) {
215			dev_put(dev);
216			return -ENODEV;
217		}
218
219		if (dn_dev_set_default(dev, 1)) {
220			dev_put(dev);
221			return -ENODEV;
222		}
223		*ppos += *lenp;
224
225		return 0;
226	}
227
228	dev = dn_dev_get_default();
229	if (dev == NULL) {
230		*lenp = 0;
231		return 0;
232	}
233
234	strcpy(devname, dev->name);
235	dev_put(dev);
236	len = strlen(devname);
237	devname[len++] = '\n';
238
239	if (len > *lenp) len = *lenp;
240
241	if (copy_to_user(buffer, devname, len))
242		return -EFAULT;
243
244	*lenp = len;
245	*ppos += len;
246
247	return 0;
248}
249
250static struct ctl_table dn_table[] = {
251	{
252		.procname = "node_address",
253		.maxlen = 7,
254		.mode = 0644,
255		.proc_handler = dn_node_address_handler,
256	},
257	{
258		.procname = "node_name",
259		.data = node_name,
260		.maxlen = 7,
261		.mode = 0644,
262		.proc_handler = proc_dostring,
263	},
264	{
265		.procname = "default_device",
266		.maxlen = 16,
267		.mode = 0644,
268		.proc_handler = dn_def_dev_handler,
269	},
270	{
271		.procname = "time_wait",
272		.data = &decnet_time_wait,
273		.maxlen = sizeof(int),
274		.mode = 0644,
275		.proc_handler = proc_dointvec_minmax,
276		.extra1 = &min_decnet_time_wait,
277		.extra2 = &max_decnet_time_wait
278	},
279	{
280		.procname = "dn_count",
281		.data = &decnet_dn_count,
282		.maxlen = sizeof(int),
283		.mode = 0644,
284		.proc_handler = proc_dointvec_minmax,
285		.extra1 = &min_state_count,
286		.extra2 = &max_state_count
287	},
288	{
289		.procname = "di_count",
290		.data = &decnet_di_count,
291		.maxlen = sizeof(int),
292		.mode = 0644,
293		.proc_handler = proc_dointvec_minmax,
294		.extra1 = &min_state_count,
295		.extra2 = &max_state_count
296	},
297	{
298		.procname = "dr_count",
299		.data = &decnet_dr_count,
300		.maxlen = sizeof(int),
301		.mode = 0644,
302		.proc_handler = proc_dointvec_minmax,
303		.extra1 = &min_state_count,
304		.extra2 = &max_state_count
305	},
306	{
307		.procname = "dst_gc_interval",
308		.data = &decnet_dst_gc_interval,
309		.maxlen = sizeof(int),
310		.mode = 0644,
311		.proc_handler = proc_dointvec_minmax,
312		.extra1 = &min_decnet_dst_gc_interval,
313		.extra2 = &max_decnet_dst_gc_interval
314	},
315	{
316		.procname = "no_fc_max_cwnd",
317		.data = &decnet_no_fc_max_cwnd,
318		.maxlen = sizeof(int),
319		.mode = 0644,
320		.proc_handler = proc_dointvec_minmax,
321		.extra1 = &min_decnet_no_fc_max_cwnd,
322		.extra2 = &max_decnet_no_fc_max_cwnd
323	},
324       {
325		.procname = "decnet_mem",
326		.data = &sysctl_decnet_mem,
327		.maxlen = sizeof(sysctl_decnet_mem),
328		.mode = 0644,
329		.proc_handler = proc_doulongvec_minmax
330	},
331	{
332		.procname = "decnet_rmem",
333		.data = &sysctl_decnet_rmem,
334		.maxlen = sizeof(sysctl_decnet_rmem),
335		.mode = 0644,
336		.proc_handler = proc_dointvec,
337	},
338	{
339		.procname = "decnet_wmem",
340		.data = &sysctl_decnet_wmem,
341		.maxlen = sizeof(sysctl_decnet_wmem),
342		.mode = 0644,
343		.proc_handler = proc_dointvec,
344	},
345	{
346		.procname = "debug",
347		.data = &decnet_debug_level,
348		.maxlen = sizeof(int),
349		.mode = 0644,
350		.proc_handler = proc_dointvec,
351	},
352	{ }
353};
354
355void dn_register_sysctl(void)
356{
357	dn_table_header = register_net_sysctl(&init_net, "net/decnet", dn_table);
358}
359
360void dn_unregister_sysctl(void)
361{
362	unregister_net_sysctl_table(dn_table_header);
363}
364
365#else  /* CONFIG_SYSCTL */
366void dn_unregister_sysctl(void)
367{
368}
369void dn_register_sysctl(void)
370{
371}
372
373#endif