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/ctype.h>
21 #include <linux/inet.h>
22 #include <linux/mm.h>
23 #include <linux/net.h>
24 #include <linux/string.h>
25 #include <linux/types.h>
26 #include <linux/percpu.h>
27 #include <linux/init.h>
28 #include <linux/ratelimit.h>
29
30 #include <net/sock.h>
31 #include <net/net_ratelimit.h>
32
33 #include <asm/byteorder.h>
34 #include <asm/uaccess.h>
35
36 DEFINE_RATELIMIT_STATE(net_ratelimit_state, 5 * HZ, 10);
37 /*
38 * All net warning printk()s should be guarded by this function.
39 */
net_ratelimit(void)40 int net_ratelimit(void)
41 {
42 return __ratelimit(&net_ratelimit_state);
43 }
44 EXPORT_SYMBOL(net_ratelimit);
45
46 /*
47 * Convert an ASCII string to binary IP.
48 * This is outside of net/ipv4/ because various code that uses IP addresses
49 * is otherwise not dependent on the TCP/IP stack.
50 */
51
in_aton(const char * str)52 __be32 in_aton(const char *str)
53 {
54 unsigned long l;
55 unsigned int val;
56 int i;
57
58 l = 0;
59 for (i = 0; i < 4; i++) {
60 l <<= 8;
61 if (*str != '\0') {
62 val = 0;
63 while (*str != '\0' && *str != '.' && *str != '\n') {
64 val *= 10;
65 val += *str - '0';
66 str++;
67 }
68 l |= val;
69 if (*str != '\0')
70 str++;
71 }
72 }
73 return htonl(l);
74 }
75 EXPORT_SYMBOL(in_aton);
76
77 #define IN6PTON_XDIGIT 0x00010000
78 #define IN6PTON_DIGIT 0x00020000
79 #define IN6PTON_COLON_MASK 0x00700000
80 #define IN6PTON_COLON_1 0x00100000 /* single : requested */
81 #define IN6PTON_COLON_2 0x00200000 /* second : requested */
82 #define IN6PTON_COLON_1_2 0x00400000 /* :: requested */
83 #define IN6PTON_DOT 0x00800000 /* . */
84 #define IN6PTON_DELIM 0x10000000
85 #define IN6PTON_NULL 0x20000000 /* first/tail */
86 #define IN6PTON_UNKNOWN 0x40000000
87
xdigit2bin(char c,int delim)88 static inline int xdigit2bin(char c, int delim)
89 {
90 int val;
91
92 if (c == delim || c == '\0')
93 return IN6PTON_DELIM;
94 if (c == ':')
95 return IN6PTON_COLON_MASK;
96 if (c == '.')
97 return IN6PTON_DOT;
98
99 val = hex_to_bin(c);
100 if (val >= 0)
101 return val | IN6PTON_XDIGIT | (val < 10 ? IN6PTON_DIGIT : 0);
102
103 if (delim == -1)
104 return IN6PTON_DELIM;
105 return IN6PTON_UNKNOWN;
106 }
107
108 /**
109 * in4_pton - convert an IPv4 address from literal to binary representation
110 * @src: the start of the IPv4 address string
111 * @srclen: the length of the string, -1 means strlen(src)
112 * @dst: the binary (u8[4] array) representation of the IPv4 address
113 * @delim: the delimiter of the IPv4 address in @src, -1 means no delimiter
114 * @end: A pointer to the end of the parsed string will be placed here
115 *
116 * Return one on success, return zero when any error occurs
117 * and @end will point to the end of the parsed string.
118 *
119 */
in4_pton(const char * src,int srclen,u8 * dst,int delim,const char ** end)120 int in4_pton(const char *src, int srclen,
121 u8 *dst,
122 int delim, const char **end)
123 {
124 const char *s;
125 u8 *d;
126 u8 dbuf[4];
127 int ret = 0;
128 int i;
129 int w = 0;
130
131 if (srclen < 0)
132 srclen = strlen(src);
133 s = src;
134 d = dbuf;
135 i = 0;
136 while(1) {
137 int c;
138 c = xdigit2bin(srclen > 0 ? *s : '\0', delim);
139 if (!(c & (IN6PTON_DIGIT | IN6PTON_DOT | IN6PTON_DELIM | IN6PTON_COLON_MASK))) {
140 goto out;
141 }
142 if (c & (IN6PTON_DOT | IN6PTON_DELIM | IN6PTON_COLON_MASK)) {
143 if (w == 0)
144 goto out;
145 *d++ = w & 0xff;
146 w = 0;
147 i++;
148 if (c & (IN6PTON_DELIM | IN6PTON_COLON_MASK)) {
149 if (i != 4)
150 goto out;
151 break;
152 }
153 goto cont;
154 }
155 w = (w * 10) + c;
156 if ((w & 0xffff) > 255) {
157 goto out;
158 }
159 cont:
160 if (i >= 4)
161 goto out;
162 s++;
163 srclen--;
164 }
165 ret = 1;
166 memcpy(dst, dbuf, sizeof(dbuf));
167 out:
168 if (end)
169 *end = s;
170 return ret;
171 }
172 EXPORT_SYMBOL(in4_pton);
173
174 /**
175 * in6_pton - convert an IPv6 address from literal to binary representation
176 * @src: the start of the IPv6 address string
177 * @srclen: the length of the string, -1 means strlen(src)
178 * @dst: the binary (u8[16] array) representation of the IPv6 address
179 * @delim: the delimiter of the IPv6 address in @src, -1 means no delimiter
180 * @end: A pointer to the end of the parsed string will be placed here
181 *
182 * Return one on success, return zero when any error occurs
183 * and @end will point to the end of the parsed string.
184 *
185 */
in6_pton(const char * src,int srclen,u8 * dst,int delim,const char ** end)186 int in6_pton(const char *src, int srclen,
187 u8 *dst,
188 int delim, const char **end)
189 {
190 const char *s, *tok = NULL;
191 u8 *d, *dc = NULL;
192 u8 dbuf[16];
193 int ret = 0;
194 int i;
195 int state = IN6PTON_COLON_1_2 | IN6PTON_XDIGIT | IN6PTON_NULL;
196 int w = 0;
197
198 memset(dbuf, 0, sizeof(dbuf));
199
200 s = src;
201 d = dbuf;
202 if (srclen < 0)
203 srclen = strlen(src);
204
205 while (1) {
206 int c;
207
208 c = xdigit2bin(srclen > 0 ? *s : '\0', delim);
209 if (!(c & state))
210 goto out;
211 if (c & (IN6PTON_DELIM | IN6PTON_COLON_MASK)) {
212 /* process one 16-bit word */
213 if (!(state & IN6PTON_NULL)) {
214 *d++ = (w >> 8) & 0xff;
215 *d++ = w & 0xff;
216 }
217 w = 0;
218 if (c & IN6PTON_DELIM) {
219 /* We've processed last word */
220 break;
221 }
222 /*
223 * COLON_1 => XDIGIT
224 * COLON_2 => XDIGIT|DELIM
225 * COLON_1_2 => COLON_2
226 */
227 switch (state & IN6PTON_COLON_MASK) {
228 case IN6PTON_COLON_2:
229 dc = d;
230 state = IN6PTON_XDIGIT | IN6PTON_DELIM;
231 if (dc - dbuf >= sizeof(dbuf))
232 state |= IN6PTON_NULL;
233 break;
234 case IN6PTON_COLON_1|IN6PTON_COLON_1_2:
235 state = IN6PTON_XDIGIT | IN6PTON_COLON_2;
236 break;
237 case IN6PTON_COLON_1:
238 state = IN6PTON_XDIGIT;
239 break;
240 case IN6PTON_COLON_1_2:
241 state = IN6PTON_COLON_2;
242 break;
243 default:
244 state = 0;
245 }
246 tok = s + 1;
247 goto cont;
248 }
249
250 if (c & IN6PTON_DOT) {
251 ret = in4_pton(tok ? tok : s, srclen + (int)(s - tok), d, delim, &s);
252 if (ret > 0) {
253 d += 4;
254 break;
255 }
256 goto out;
257 }
258
259 w = (w << 4) | (0xff & c);
260 state = IN6PTON_COLON_1 | IN6PTON_DELIM;
261 if (!(w & 0xf000)) {
262 state |= IN6PTON_XDIGIT;
263 }
264 if (!dc && d + 2 < dbuf + sizeof(dbuf)) {
265 state |= IN6PTON_COLON_1_2;
266 state &= ~IN6PTON_DELIM;
267 }
268 if (d + 2 >= dbuf + sizeof(dbuf)) {
269 state &= ~(IN6PTON_COLON_1|IN6PTON_COLON_1_2);
270 }
271 cont:
272 if ((dc && d + 4 < dbuf + sizeof(dbuf)) ||
273 d + 4 == dbuf + sizeof(dbuf)) {
274 state |= IN6PTON_DOT;
275 }
276 if (d >= dbuf + sizeof(dbuf)) {
277 state &= ~(IN6PTON_XDIGIT|IN6PTON_COLON_MASK);
278 }
279 s++;
280 srclen--;
281 }
282
283 i = 15; d--;
284
285 if (dc) {
286 while(d >= dc)
287 dst[i--] = *d--;
288 while(i >= dc - dbuf)
289 dst[i--] = 0;
290 while(i >= 0)
291 dst[i--] = *d--;
292 } else
293 memcpy(dst, dbuf, sizeof(dbuf));
294
295 ret = 1;
296 out:
297 if (end)
298 *end = s;
299 return ret;
300 }
301 EXPORT_SYMBOL(in6_pton);
302
inet_proto_csum_replace4(__sum16 * sum,struct sk_buff * skb,__be32 from,__be32 to,bool pseudohdr)303 void inet_proto_csum_replace4(__sum16 *sum, struct sk_buff *skb,
304 __be32 from, __be32 to, bool pseudohdr)
305 {
306 if (skb->ip_summed != CHECKSUM_PARTIAL) {
307 csum_replace4(sum, from, to);
308 if (skb->ip_summed == CHECKSUM_COMPLETE && pseudohdr)
309 skb->csum = ~csum_add(csum_sub(~(skb->csum),
310 (__force __wsum)from),
311 (__force __wsum)to);
312 } else if (pseudohdr)
313 *sum = ~csum_fold(csum_add(csum_sub(csum_unfold(*sum),
314 (__force __wsum)from),
315 (__force __wsum)to));
316 }
317 EXPORT_SYMBOL(inet_proto_csum_replace4);
318
319 /**
320 * inet_proto_csum_replace16 - update layer 4 header checksum field
321 * @sum: Layer 4 header checksum field
322 * @skb: sk_buff for the packet
323 * @from: old IPv6 address
324 * @to: new IPv6 address
325 * @pseudohdr: True if layer 4 header checksum includes pseudoheader
326 *
327 * Update layer 4 header as per the update in IPv6 src/dst address.
328 *
329 * There is no need to update skb->csum in this function, because update in two
330 * fields a.) IPv6 src/dst address and b.) L4 header checksum cancels each other
331 * for skb->csum calculation. Whereas inet_proto_csum_replace4 function needs to
332 * update skb->csum, because update in 3 fields a.) IPv4 src/dst address,
333 * b.) IPv4 Header checksum and c.) L4 header checksum results in same diff as
334 * L4 Header checksum for skb->csum calculation.
335 */
inet_proto_csum_replace16(__sum16 * sum,struct sk_buff * skb,const __be32 * from,const __be32 * to,bool pseudohdr)336 void inet_proto_csum_replace16(__sum16 *sum, struct sk_buff *skb,
337 const __be32 *from, const __be32 *to,
338 bool pseudohdr)
339 {
340 __be32 diff[] = {
341 ~from[0], ~from[1], ~from[2], ~from[3],
342 to[0], to[1], to[2], to[3],
343 };
344 if (skb->ip_summed != CHECKSUM_PARTIAL) {
345 *sum = csum_fold(csum_partial(diff, sizeof(diff),
346 ~csum_unfold(*sum)));
347 } else if (pseudohdr)
348 *sum = ~csum_fold(csum_partial(diff, sizeof(diff),
349 csum_unfold(*sum)));
350 }
351 EXPORT_SYMBOL(inet_proto_csum_replace16);
352
inet_proto_csum_replace_by_diff(__sum16 * sum,struct sk_buff * skb,__wsum diff,bool pseudohdr)353 void inet_proto_csum_replace_by_diff(__sum16 *sum, struct sk_buff *skb,
354 __wsum diff, bool pseudohdr)
355 {
356 if (skb->ip_summed != CHECKSUM_PARTIAL) {
357 *sum = csum_fold(csum_add(diff, ~csum_unfold(*sum)));
358 if (skb->ip_summed == CHECKSUM_COMPLETE && pseudohdr)
359 skb->csum = ~csum_add(diff, ~skb->csum);
360 } else if (pseudohdr) {
361 *sum = ~csum_fold(csum_add(diff, csum_unfold(*sum)));
362 }
363 }
364 EXPORT_SYMBOL(inet_proto_csum_replace_by_diff);
365