ec6bb322f3722f8e4070e7eb66ddbc5d2a88548b
[linux-3.10.git] / net / core / utils.c
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 EXPORT_SYMBOL(in_aton);
81
82 #define IN6PTON_XDIGIT          0x00010000
83 #define IN6PTON_DIGIT           0x00020000
84 #define IN6PTON_COLON_MASK      0x00700000
85 #define IN6PTON_COLON_1         0x00100000      /* single : requested */
86 #define IN6PTON_COLON_2         0x00200000      /* second : requested */
87 #define IN6PTON_COLON_1_2       0x00400000      /* :: requested */
88 #define IN6PTON_DOT             0x00800000      /* . */
89 #define IN6PTON_DELIM           0x10000000
90 #define IN6PTON_NULL            0x20000000      /* first/tail */
91 #define IN6PTON_UNKNOWN         0x40000000
92
93 static inline int xdigit2bin(char c, int delim)
94 {
95         int val;
96
97         if (c == delim || c == '\0')
98                 return IN6PTON_DELIM;
99         if (c == ':')
100                 return IN6PTON_COLON_MASK;
101         if (c == '.')
102                 return IN6PTON_DOT;
103
104         val = hex_to_bin(c);
105         if (val >= 0)
106                 return val | IN6PTON_XDIGIT | (val < 10 ? IN6PTON_DIGIT : 0);
107
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 EXPORT_SYMBOL(in4_pton);
166
167 int in6_pton(const char *src, int srclen,
168              u8 *dst,
169              int delim, const char **end)
170 {
171         const char *s, *tok = NULL;
172         u8 *d, *dc = NULL;
173         u8 dbuf[16];
174         int ret = 0;
175         int i;
176         int state = IN6PTON_COLON_1_2 | IN6PTON_XDIGIT | IN6PTON_NULL;
177         int w = 0;
178
179         memset(dbuf, 0, sizeof(dbuf));
180
181         s = src;
182         d = dbuf;
183         if (srclen < 0)
184                 srclen = strlen(src);
185
186         while (1) {
187                 int c;
188
189                 c = xdigit2bin(srclen > 0 ? *s : '\0', delim);
190                 if (!(c & state))
191                         goto out;
192                 if (c & (IN6PTON_DELIM | IN6PTON_COLON_MASK)) {
193                         /* process one 16-bit word */
194                         if (!(state & IN6PTON_NULL)) {
195                                 *d++ = (w >> 8) & 0xff;
196                                 *d++ = w & 0xff;
197                         }
198                         w = 0;
199                         if (c & IN6PTON_DELIM) {
200                                 /* We've processed last word */
201                                 break;
202                         }
203                         /*
204                          * COLON_1 => XDIGIT
205                          * COLON_2 => XDIGIT|DELIM
206                          * COLON_1_2 => COLON_2
207                          */
208                         switch (state & IN6PTON_COLON_MASK) {
209                         case IN6PTON_COLON_2:
210                                 dc = d;
211                                 state = IN6PTON_XDIGIT | IN6PTON_DELIM;
212                                 if (dc - dbuf >= sizeof(dbuf))
213                                         state |= IN6PTON_NULL;
214                                 break;
215                         case IN6PTON_COLON_1|IN6PTON_COLON_1_2:
216                                 state = IN6PTON_XDIGIT | IN6PTON_COLON_2;
217                                 break;
218                         case IN6PTON_COLON_1:
219                                 state = IN6PTON_XDIGIT;
220                                 break;
221                         case IN6PTON_COLON_1_2:
222                                 state = IN6PTON_COLON_2;
223                                 break;
224                         default:
225                                 state = 0;
226                         }
227                         tok = s + 1;
228                         goto cont;
229                 }
230
231                 if (c & IN6PTON_DOT) {
232                         ret = in4_pton(tok ? tok : s, srclen + (int)(s - tok), d, delim, &s);
233                         if (ret > 0) {
234                                 d += 4;
235                                 break;
236                         }
237                         goto out;
238                 }
239
240                 w = (w << 4) | (0xff & c);
241                 state = IN6PTON_COLON_1 | IN6PTON_DELIM;
242                 if (!(w & 0xf000)) {
243                         state |= IN6PTON_XDIGIT;
244                 }
245                 if (!dc && d + 2 < dbuf + sizeof(dbuf)) {
246                         state |= IN6PTON_COLON_1_2;
247                         state &= ~IN6PTON_DELIM;
248                 }
249                 if (d + 2 >= dbuf + sizeof(dbuf)) {
250                         state &= ~(IN6PTON_COLON_1|IN6PTON_COLON_1_2);
251                 }
252 cont:
253                 if ((dc && d + 4 < dbuf + sizeof(dbuf)) ||
254                     d + 4 == dbuf + sizeof(dbuf)) {
255                         state |= IN6PTON_DOT;
256                 }
257                 if (d >= dbuf + sizeof(dbuf)) {
258                         state &= ~(IN6PTON_XDIGIT|IN6PTON_COLON_MASK);
259                 }
260                 s++;
261                 srclen--;
262         }
263
264         i = 15; d--;
265
266         if (dc) {
267                 while(d >= dc)
268                         dst[i--] = *d--;
269                 while(i >= dc - dbuf)
270                         dst[i--] = 0;
271                 while(i >= 0)
272                         dst[i--] = *d--;
273         } else
274                 memcpy(dst, dbuf, sizeof(dbuf));
275
276         ret = 1;
277 out:
278         if (end)
279                 *end = s;
280         return ret;
281 }
282 EXPORT_SYMBOL(in6_pton);
283
284 void inet_proto_csum_replace4(__sum16 *sum, struct sk_buff *skb,
285                               __be32 from, __be32 to, int pseudohdr)
286 {
287         __be32 diff[] = { ~from, to };
288         if (skb->ip_summed != CHECKSUM_PARTIAL) {
289                 *sum = csum_fold(csum_partial(diff, sizeof(diff),
290                                 ~csum_unfold(*sum)));
291                 if (skb->ip_summed == CHECKSUM_COMPLETE && pseudohdr)
292                         skb->csum = ~csum_partial(diff, sizeof(diff),
293                                                 ~skb->csum);
294         } else if (pseudohdr)
295                 *sum = ~csum_fold(csum_partial(diff, sizeof(diff),
296                                 csum_unfold(*sum)));
297 }
298 EXPORT_SYMBOL(inet_proto_csum_replace4);