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
35int net_msg_warn __read_mostly = 1;
36EXPORT_SYMBOL(net_msg_warn);
37
38DEFINE_RATELIMIT_STATE(net_ratelimit_state, 5 * HZ, 10);
39/*
40 * All net warning printk()s should be guarded by this function.
41 */
42int net_ratelimit(void)
43{
44	return __ratelimit(&net_ratelimit_state);
45}
46EXPORT_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}
80EXPORT_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
93static inline int xdigit2bin(char c, int delim)
94{
95	if (c == delim || c == '\0')
96		return IN6PTON_DELIM;
97	if (c == ':')
98		return IN6PTON_COLON_MASK;
99	if (c == '.')
100		return IN6PTON_DOT;
101	if (c >= '0' && c <= '9')
102		return (IN6PTON_XDIGIT | IN6PTON_DIGIT| (c - '0'));
103	if (c >= 'a' && c <= 'f')
104		return (IN6PTON_XDIGIT | (c - 'a' + 10));
105	if (c >= 'A' && c <= 'F')
106		return (IN6PTON_XDIGIT | (c - 'A' + 10));
107	if (delim == -1)
108		return IN6PTON_DELIM;
109	return IN6PTON_UNKNOWN;
110}
111
112int in4_pton(const char *src, int srclen,
113	     u8 *dst,
114	     int delim, const char **end)
115{
116	const char *s;
117	u8 *d;
118	u8 dbuf[4];
119	int ret = 0;
120	int i;
121	int w = 0;
122
123	if (srclen < 0)
124		srclen = strlen(src);
125	s = src;
126	d = dbuf;
127	i = 0;
128	while(1) {
129		int c;
130		c = xdigit2bin(srclen > 0 ? *s : '\0', delim);
131		if (!(c & (IN6PTON_DIGIT | IN6PTON_DOT | IN6PTON_DELIM | IN6PTON_COLON_MASK))) {
132			goto out;
133		}
134		if (c & (IN6PTON_DOT | IN6PTON_DELIM | IN6PTON_COLON_MASK)) {
135			if (w == 0)
136				goto out;
137			*d++ = w & 0xff;
138			w = 0;
139			i++;
140			if (c & (IN6PTON_DELIM | IN6PTON_COLON_MASK)) {
141				if (i != 4)
142					goto out;
143				break;
144			}
145			goto cont;
146		}
147		w = (w * 10) + c;
148		if ((w & 0xffff) > 255) {
149			goto out;
150		}
151cont:
152		if (i >= 4)
153			goto out;
154		s++;
155		srclen--;
156	}
157	ret = 1;
158	memcpy(dst, dbuf, sizeof(dbuf));
159out:
160	if (end)
161		*end = s;
162	return ret;
163}
164EXPORT_SYMBOL(in4_pton);
165
166int in6_pton(const char *src, int srclen,
167	     u8 *dst,
168	     int delim, const char **end)
169{
170	const char *s, *tok = NULL;
171	u8 *d, *dc = NULL;
172	u8 dbuf[16];
173	int ret = 0;
174	int i;
175	int state = IN6PTON_COLON_1_2 | IN6PTON_XDIGIT | IN6PTON_NULL;
176	int w = 0;
177
178	memset(dbuf, 0, sizeof(dbuf));
179
180	s = src;
181	d = dbuf;
182	if (srclen < 0)
183		srclen = strlen(src);
184
185	while (1) {
186		int c;
187
188		c = xdigit2bin(srclen > 0 ? *s : '\0', delim);
189		if (!(c & state))
190			goto out;
191		if (c & (IN6PTON_DELIM | IN6PTON_COLON_MASK)) {
192			/* process one 16-bit word */
193			if (!(state & IN6PTON_NULL)) {
194				*d++ = (w >> 8) & 0xff;
195				*d++ = w & 0xff;
196			}
197			w = 0;
198			if (c & IN6PTON_DELIM) {
199				/* We've processed last word */
200				break;
201			}
202			/*
203			 * COLON_1 => XDIGIT
204			 * COLON_2 => XDIGIT|DELIM
205			 * COLON_1_2 => COLON_2
206			 */
207			switch (state & IN6PTON_COLON_MASK) {
208			case IN6PTON_COLON_2:
209				dc = d;
210				state = IN6PTON_XDIGIT | IN6PTON_DELIM;
211				if (dc - dbuf >= sizeof(dbuf))
212					state |= IN6PTON_NULL;
213				break;
214			case IN6PTON_COLON_1|IN6PTON_COLON_1_2:
215				state = IN6PTON_XDIGIT | IN6PTON_COLON_2;
216				break;
217			case IN6PTON_COLON_1:
218				state = IN6PTON_XDIGIT;
219				break;
220			case IN6PTON_COLON_1_2:
221				state = IN6PTON_COLON_2;
222				break;
223			default:
224				state = 0;
225			}
226			tok = s + 1;
227			goto cont;
228		}
229
230		if (c & IN6PTON_DOT) {
231			ret = in4_pton(tok ? tok : s, srclen + (int)(s - tok), d, delim, &s);
232			if (ret > 0) {
233				d += 4;
234				break;
235			}
236			goto out;
237		}
238
239		w = (w << 4) | (0xff & c);
240		state = IN6PTON_COLON_1 | IN6PTON_DELIM;
241		if (!(w & 0xf000)) {
242			state |= IN6PTON_XDIGIT;
243		}
244		if (!dc && d + 2 < dbuf + sizeof(dbuf)) {
245			state |= IN6PTON_COLON_1_2;
246			state &= ~IN6PTON_DELIM;
247		}
248		if (d + 2 >= dbuf + sizeof(dbuf)) {
249			state &= ~(IN6PTON_COLON_1|IN6PTON_COLON_1_2);
250		}
251cont:
252		if ((dc && d + 4 < dbuf + sizeof(dbuf)) ||
253		    d + 4 == dbuf + sizeof(dbuf)) {
254			state |= IN6PTON_DOT;
255		}
256		if (d >= dbuf + sizeof(dbuf)) {
257			state &= ~(IN6PTON_XDIGIT|IN6PTON_COLON_MASK);
258		}
259		s++;
260		srclen--;
261	}
262
263	i = 15; d--;
264
265	if (dc) {
266		while(d >= dc)
267			dst[i--] = *d--;
268		while(i >= dc - dbuf)
269			dst[i--] = 0;
270		while(i >= 0)
271			dst[i--] = *d--;
272	} else
273		memcpy(dst, dbuf, sizeof(dbuf));
274
275	ret = 1;
276out:
277	if (end)
278		*end = s;
279	return ret;
280}
281EXPORT_SYMBOL(in6_pton);
282
283void inet_proto_csum_replace4(__sum16 *sum, struct sk_buff *skb,
284			      __be32 from, __be32 to, int pseudohdr)
285{
286	__be32 diff[] = { ~from, to };
287	if (skb->ip_summed != CHECKSUM_PARTIAL) {
288		*sum = csum_fold(csum_partial(diff, sizeof(diff),
289				~csum_unfold(*sum)));
290		if (skb->ip_summed == CHECKSUM_COMPLETE && pseudohdr)
291			skb->csum = ~csum_partial(diff, sizeof(diff),
292						~skb->csum);
293	} else if (pseudohdr)
294		*sum = ~csum_fold(csum_partial(diff, sizeof(diff),
295				csum_unfold(*sum)));
296}
297EXPORT_SYMBOL(inet_proto_csum_replace4);
298