xref: /openbmc/linux/net/core/utils.c (revision 9d56dd3b083a3bec56e9da35ce07baca81030b03)
1 /*
2  *	Generic address resultion entity
3  *
4  *	Authors:
5  *	net_random Alan Cox
6  *	net_ratelimit Andi Kleen
7  *	in{4,6}_pton YOSHIFUJI Hideaki, Copyright (C)2006 USAGI/WIDE Project
8  *
9  *	Created by Alexey Kuznetsov <kuznet@ms2.inr.ac.ru>
10  *
11  *	This program is free software; you can redistribute it and/or
12  *      modify it under the terms of the GNU General Public License
13  *      as published by the Free Software Foundation; either version
14  *      2 of the License, or (at your option) any later version.
15  */
16 
17 #include <linux/module.h>
18 #include <linux/jiffies.h>
19 #include <linux/kernel.h>
20 #include <linux/inet.h>
21 #include <linux/mm.h>
22 #include <linux/net.h>
23 #include <linux/string.h>
24 #include <linux/types.h>
25 #include <linux/percpu.h>
26 #include <linux/init.h>
27 #include <linux/ratelimit.h>
28 
29 #include <net/sock.h>
30 
31 #include <asm/byteorder.h>
32 #include <asm/system.h>
33 #include <asm/uaccess.h>
34 
35 int net_msg_warn __read_mostly = 1;
36 EXPORT_SYMBOL(net_msg_warn);
37 
38 DEFINE_RATELIMIT_STATE(net_ratelimit_state, 5 * HZ, 10);
39 /*
40  * All net warning printk()s should be guarded by this function.
41  */
42 int net_ratelimit(void)
43 {
44 	return __ratelimit(&net_ratelimit_state);
45 }
46 EXPORT_SYMBOL(net_ratelimit);
47 
48 /*
49  * Convert an ASCII string to binary IP.
50  * This is outside of net/ipv4/ because various code that uses IP addresses
51  * is otherwise not dependent on the TCP/IP stack.
52  */
53 
54 __be32 in_aton(const char *str)
55 {
56 	unsigned long l;
57 	unsigned int val;
58 	int i;
59 
60 	l = 0;
61 	for (i = 0; i < 4; i++)
62 	{
63 		l <<= 8;
64 		if (*str != '\0')
65 		{
66 			val = 0;
67 			while (*str != '\0' && *str != '.' && *str != '\n')
68 			{
69 				val *= 10;
70 				val += *str - '0';
71 				str++;
72 			}
73 			l |= val;
74 			if (*str != '\0')
75 				str++;
76 		}
77 	}
78 	return(htonl(l));
79 }
80 
81 EXPORT_SYMBOL(in_aton);
82 
83 #define IN6PTON_XDIGIT		0x00010000
84 #define IN6PTON_DIGIT		0x00020000
85 #define IN6PTON_COLON_MASK	0x00700000
86 #define IN6PTON_COLON_1		0x00100000	/* single : requested */
87 #define IN6PTON_COLON_2		0x00200000	/* second : requested */
88 #define IN6PTON_COLON_1_2	0x00400000	/* :: requested */
89 #define IN6PTON_DOT		0x00800000	/* . */
90 #define IN6PTON_DELIM		0x10000000
91 #define IN6PTON_NULL		0x20000000	/* first/tail */
92 #define IN6PTON_UNKNOWN		0x40000000
93 
94 static inline int xdigit2bin(char c, int delim)
95 {
96 	if (c == delim || c == '\0')
97 		return IN6PTON_DELIM;
98 	if (c == ':')
99 		return IN6PTON_COLON_MASK;
100 	if (c == '.')
101 		return IN6PTON_DOT;
102 	if (c >= '0' && c <= '9')
103 		return (IN6PTON_XDIGIT | IN6PTON_DIGIT| (c - '0'));
104 	if (c >= 'a' && c <= 'f')
105 		return (IN6PTON_XDIGIT | (c - 'a' + 10));
106 	if (c >= 'A' && c <= 'F')
107 		return (IN6PTON_XDIGIT | (c - 'A' + 10));
108 	if (delim == -1)
109 		return IN6PTON_DELIM;
110 	return IN6PTON_UNKNOWN;
111 }
112 
113 int in4_pton(const char *src, int srclen,
114 	     u8 *dst,
115 	     int delim, const char **end)
116 {
117 	const char *s;
118 	u8 *d;
119 	u8 dbuf[4];
120 	int ret = 0;
121 	int i;
122 	int w = 0;
123 
124 	if (srclen < 0)
125 		srclen = strlen(src);
126 	s = src;
127 	d = dbuf;
128 	i = 0;
129 	while(1) {
130 		int c;
131 		c = xdigit2bin(srclen > 0 ? *s : '\0', delim);
132 		if (!(c & (IN6PTON_DIGIT | IN6PTON_DOT | IN6PTON_DELIM | IN6PTON_COLON_MASK))) {
133 			goto out;
134 		}
135 		if (c & (IN6PTON_DOT | IN6PTON_DELIM | IN6PTON_COLON_MASK)) {
136 			if (w == 0)
137 				goto out;
138 			*d++ = w & 0xff;
139 			w = 0;
140 			i++;
141 			if (c & (IN6PTON_DELIM | IN6PTON_COLON_MASK)) {
142 				if (i != 4)
143 					goto out;
144 				break;
145 			}
146 			goto cont;
147 		}
148 		w = (w * 10) + c;
149 		if ((w & 0xffff) > 255) {
150 			goto out;
151 		}
152 cont:
153 		if (i >= 4)
154 			goto out;
155 		s++;
156 		srclen--;
157 	}
158 	ret = 1;
159 	memcpy(dst, dbuf, sizeof(dbuf));
160 out:
161 	if (end)
162 		*end = s;
163 	return ret;
164 }
165 
166 EXPORT_SYMBOL(in4_pton);
167 
168 int in6_pton(const char *src, int srclen,
169 	     u8 *dst,
170 	     int delim, const char **end)
171 {
172 	const char *s, *tok = NULL;
173 	u8 *d, *dc = NULL;
174 	u8 dbuf[16];
175 	int ret = 0;
176 	int i;
177 	int state = IN6PTON_COLON_1_2 | IN6PTON_XDIGIT | IN6PTON_NULL;
178 	int w = 0;
179 
180 	memset(dbuf, 0, sizeof(dbuf));
181 
182 	s = src;
183 	d = dbuf;
184 	if (srclen < 0)
185 		srclen = strlen(src);
186 
187 	while (1) {
188 		int c;
189 
190 		c = xdigit2bin(srclen > 0 ? *s : '\0', delim);
191 		if (!(c & state))
192 			goto out;
193 		if (c & (IN6PTON_DELIM | IN6PTON_COLON_MASK)) {
194 			/* process one 16-bit word */
195 			if (!(state & IN6PTON_NULL)) {
196 				*d++ = (w >> 8) & 0xff;
197 				*d++ = w & 0xff;
198 			}
199 			w = 0;
200 			if (c & IN6PTON_DELIM) {
201 				/* We've processed last word */
202 				break;
203 			}
204 			/*
205 			 * COLON_1 => XDIGIT
206 			 * COLON_2 => XDIGIT|DELIM
207 			 * COLON_1_2 => COLON_2
208 			 */
209 			switch (state & IN6PTON_COLON_MASK) {
210 			case IN6PTON_COLON_2:
211 				dc = d;
212 				state = IN6PTON_XDIGIT | IN6PTON_DELIM;
213 				if (dc - dbuf >= sizeof(dbuf))
214 					state |= IN6PTON_NULL;
215 				break;
216 			case IN6PTON_COLON_1|IN6PTON_COLON_1_2:
217 				state = IN6PTON_XDIGIT | IN6PTON_COLON_2;
218 				break;
219 			case IN6PTON_COLON_1:
220 				state = IN6PTON_XDIGIT;
221 				break;
222 			case IN6PTON_COLON_1_2:
223 				state = IN6PTON_COLON_2;
224 				break;
225 			default:
226 				state = 0;
227 			}
228 			tok = s + 1;
229 			goto cont;
230 		}
231 
232 		if (c & IN6PTON_DOT) {
233 			ret = in4_pton(tok ? tok : s, srclen + (int)(s - tok), d, delim, &s);
234 			if (ret > 0) {
235 				d += 4;
236 				break;
237 			}
238 			goto out;
239 		}
240 
241 		w = (w << 4) | (0xff & c);
242 		state = IN6PTON_COLON_1 | IN6PTON_DELIM;
243 		if (!(w & 0xf000)) {
244 			state |= IN6PTON_XDIGIT;
245 		}
246 		if (!dc && d + 2 < dbuf + sizeof(dbuf)) {
247 			state |= IN6PTON_COLON_1_2;
248 			state &= ~IN6PTON_DELIM;
249 		}
250 		if (d + 2 >= dbuf + sizeof(dbuf)) {
251 			state &= ~(IN6PTON_COLON_1|IN6PTON_COLON_1_2);
252 		}
253 cont:
254 		if ((dc && d + 4 < dbuf + sizeof(dbuf)) ||
255 		    d + 4 == dbuf + sizeof(dbuf)) {
256 			state |= IN6PTON_DOT;
257 		}
258 		if (d >= dbuf + sizeof(dbuf)) {
259 			state &= ~(IN6PTON_XDIGIT|IN6PTON_COLON_MASK);
260 		}
261 		s++;
262 		srclen--;
263 	}
264 
265 	i = 15; d--;
266 
267 	if (dc) {
268 		while(d >= dc)
269 			dst[i--] = *d--;
270 		while(i >= dc - dbuf)
271 			dst[i--] = 0;
272 		while(i >= 0)
273 			dst[i--] = *d--;
274 	} else
275 		memcpy(dst, dbuf, sizeof(dbuf));
276 
277 	ret = 1;
278 out:
279 	if (end)
280 		*end = s;
281 	return ret;
282 }
283 
284 EXPORT_SYMBOL(in6_pton);
285 
286 void inet_proto_csum_replace4(__sum16 *sum, struct sk_buff *skb,
287 			      __be32 from, __be32 to, int pseudohdr)
288 {
289 	__be32 diff[] = { ~from, to };
290 	if (skb->ip_summed != CHECKSUM_PARTIAL) {
291 		*sum = csum_fold(csum_partial(diff, sizeof(diff),
292 				~csum_unfold(*sum)));
293 		if (skb->ip_summed == CHECKSUM_COMPLETE && pseudohdr)
294 			skb->csum = ~csum_partial(diff, sizeof(diff),
295 						~skb->csum);
296 	} else if (pseudohdr)
297 		*sum = ~csum_fold(csum_partial(diff, sizeof(diff),
298 				csum_unfold(*sum)));
299 }
300 EXPORT_SYMBOL(inet_proto_csum_replace4);
301