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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
36int net_msg_warn __read_mostly = 1;
37EXPORT_SYMBOL(net_msg_warn);
38
39DEFINE_RATELIMIT_STATE(net_ratelimit_state, 5 * HZ, 10);
40/*
41 * All net warning printk()s should be guarded by this function.
42 */
43int net_ratelimit(void)
44{
45 return __ratelimit(&net_ratelimit_state);
46}
47EXPORT_SYMBOL(net_ratelimit);
48
49/*
50 * Convert an ASCII string to binary IP.
51 * This is outside of net/ipv4/ because various code that uses IP addresses
52 * is otherwise not dependent on the TCP/IP stack.
53 */
54
55__be32 in_aton(const char *str)
56{
57 unsigned long l;
58 unsigned int val;
59 int i;
60
61 l = 0;
62 for (i = 0; i < 4; i++) {
63 l <<= 8;
64 if (*str != '\0') {
65 val = 0;
66 while (*str != '\0' && *str != '.' && *str != '\n') {
67 val *= 10;
68 val += *str - '0';
69 str++;
70 }
71 l |= val;
72 if (*str != '\0')
73 str++;
74 }
75 }
76 return htonl(l);
77}
78EXPORT_SYMBOL(in_aton);
79
80#define IN6PTON_XDIGIT 0x00010000
81#define IN6PTON_DIGIT 0x00020000
82#define IN6PTON_COLON_MASK 0x00700000
83#define IN6PTON_COLON_1 0x00100000 /* single : requested */
84#define IN6PTON_COLON_2 0x00200000 /* second : requested */
85#define IN6PTON_COLON_1_2 0x00400000 /* :: requested */
86#define IN6PTON_DOT 0x00800000 /* . */
87#define IN6PTON_DELIM 0x10000000
88#define IN6PTON_NULL 0x20000000 /* first/tail */
89#define IN6PTON_UNKNOWN 0x40000000
90
91static inline int xdigit2bin(char c, int delim)
92{
93 int val;
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
102 val = hex_to_bin(c);
103 if (val >= 0)
104 return val | IN6PTON_XDIGIT | (val < 10 ? IN6PTON_DIGIT : 0);
105
106 if (delim == -1)
107 return IN6PTON_DELIM;
108 return IN6PTON_UNKNOWN;
109}
110
111/**
112 * in4_pton - convert an IPv4 address from literal to binary representation
113 * @src: the start of the IPv4 address string
114 * @srclen: the length of the string, -1 means strlen(src)
115 * @dst: the binary (u8[4] array) representation of the IPv4 address
116 * @delim: the delimiter of the IPv4 address in @src, -1 means no delimiter
117 * @end: A pointer to the end of the parsed string will be placed here
118 *
119 * Return one on success, return zero when any error occurs
120 * and @end will point to the end of the parsed string.
121 *
122 */
123int in4_pton(const char *src, int srclen,
124 u8 *dst,
125 int delim, const char **end)
126{
127 const char *s;
128 u8 *d;
129 u8 dbuf[4];
130 int ret = 0;
131 int i;
132 int w = 0;
133
134 if (srclen < 0)
135 srclen = strlen(src);
136 s = src;
137 d = dbuf;
138 i = 0;
139 while(1) {
140 int c;
141 c = xdigit2bin(srclen > 0 ? *s : '\0', delim);
142 if (!(c & (IN6PTON_DIGIT | IN6PTON_DOT | IN6PTON_DELIM | IN6PTON_COLON_MASK))) {
143 goto out;
144 }
145 if (c & (IN6PTON_DOT | IN6PTON_DELIM | IN6PTON_COLON_MASK)) {
146 if (w == 0)
147 goto out;
148 *d++ = w & 0xff;
149 w = 0;
150 i++;
151 if (c & (IN6PTON_DELIM | IN6PTON_COLON_MASK)) {
152 if (i != 4)
153 goto out;
154 break;
155 }
156 goto cont;
157 }
158 w = (w * 10) + c;
159 if ((w & 0xffff) > 255) {
160 goto out;
161 }
162cont:
163 if (i >= 4)
164 goto out;
165 s++;
166 srclen--;
167 }
168 ret = 1;
169 memcpy(dst, dbuf, sizeof(dbuf));
170out:
171 if (end)
172 *end = s;
173 return ret;
174}
175EXPORT_SYMBOL(in4_pton);
176
177/**
178 * in6_pton - convert an IPv6 address from literal to binary representation
179 * @src: the start of the IPv6 address string
180 * @srclen: the length of the string, -1 means strlen(src)
181 * @dst: the binary (u8[16] array) representation of the IPv6 address
182 * @delim: the delimiter of the IPv6 address in @src, -1 means no delimiter
183 * @end: A pointer to the end of the parsed string will be placed here
184 *
185 * Return one on success, return zero when any error occurs
186 * and @end will point to the end of the parsed string.
187 *
188 */
189int in6_pton(const char *src, int srclen,
190 u8 *dst,
191 int delim, const char **end)
192{
193 const char *s, *tok = NULL;
194 u8 *d, *dc = NULL;
195 u8 dbuf[16];
196 int ret = 0;
197 int i;
198 int state = IN6PTON_COLON_1_2 | IN6PTON_XDIGIT | IN6PTON_NULL;
199 int w = 0;
200
201 memset(dbuf, 0, sizeof(dbuf));
202
203 s = src;
204 d = dbuf;
205 if (srclen < 0)
206 srclen = strlen(src);
207
208 while (1) {
209 int c;
210
211 c = xdigit2bin(srclen > 0 ? *s : '\0', delim);
212 if (!(c & state))
213 goto out;
214 if (c & (IN6PTON_DELIM | IN6PTON_COLON_MASK)) {
215 /* process one 16-bit word */
216 if (!(state & IN6PTON_NULL)) {
217 *d++ = (w >> 8) & 0xff;
218 *d++ = w & 0xff;
219 }
220 w = 0;
221 if (c & IN6PTON_DELIM) {
222 /* We've processed last word */
223 break;
224 }
225 /*
226 * COLON_1 => XDIGIT
227 * COLON_2 => XDIGIT|DELIM
228 * COLON_1_2 => COLON_2
229 */
230 switch (state & IN6PTON_COLON_MASK) {
231 case IN6PTON_COLON_2:
232 dc = d;
233 state = IN6PTON_XDIGIT | IN6PTON_DELIM;
234 if (dc - dbuf >= sizeof(dbuf))
235 state |= IN6PTON_NULL;
236 break;
237 case IN6PTON_COLON_1|IN6PTON_COLON_1_2:
238 state = IN6PTON_XDIGIT | IN6PTON_COLON_2;
239 break;
240 case IN6PTON_COLON_1:
241 state = IN6PTON_XDIGIT;
242 break;
243 case IN6PTON_COLON_1_2:
244 state = IN6PTON_COLON_2;
245 break;
246 default:
247 state = 0;
248 }
249 tok = s + 1;
250 goto cont;
251 }
252
253 if (c & IN6PTON_DOT) {
254 ret = in4_pton(tok ? tok : s, srclen + (int)(s - tok), d, delim, &s);
255 if (ret > 0) {
256 d += 4;
257 break;
258 }
259 goto out;
260 }
261
262 w = (w << 4) | (0xff & c);
263 state = IN6PTON_COLON_1 | IN6PTON_DELIM;
264 if (!(w & 0xf000)) {
265 state |= IN6PTON_XDIGIT;
266 }
267 if (!dc && d + 2 < dbuf + sizeof(dbuf)) {
268 state |= IN6PTON_COLON_1_2;
269 state &= ~IN6PTON_DELIM;
270 }
271 if (d + 2 >= dbuf + sizeof(dbuf)) {
272 state &= ~(IN6PTON_COLON_1|IN6PTON_COLON_1_2);
273 }
274cont:
275 if ((dc && d + 4 < dbuf + sizeof(dbuf)) ||
276 d + 4 == dbuf + sizeof(dbuf)) {
277 state |= IN6PTON_DOT;
278 }
279 if (d >= dbuf + sizeof(dbuf)) {
280 state &= ~(IN6PTON_XDIGIT|IN6PTON_COLON_MASK);
281 }
282 s++;
283 srclen--;
284 }
285
286 i = 15; d--;
287
288 if (dc) {
289 while(d >= dc)
290 dst[i--] = *d--;
291 while(i >= dc - dbuf)
292 dst[i--] = 0;
293 while(i >= 0)
294 dst[i--] = *d--;
295 } else
296 memcpy(dst, dbuf, sizeof(dbuf));
297
298 ret = 1;
299out:
300 if (end)
301 *end = s;
302 return ret;
303}
304EXPORT_SYMBOL(in6_pton);
305
306void inet_proto_csum_replace4(__sum16 *sum, struct sk_buff *skb,
307 __be32 from, __be32 to, int pseudohdr)
308{
309 __be32 diff[] = { ~from, to };
310 if (skb->ip_summed != CHECKSUM_PARTIAL) {
311 *sum = csum_fold(csum_partial(diff, sizeof(diff),
312 ~csum_unfold(*sum)));
313 if (skb->ip_summed == CHECKSUM_COMPLETE && pseudohdr)
314 skb->csum = ~csum_partial(diff, sizeof(diff),
315 ~skb->csum);
316 } else if (pseudohdr)
317 *sum = ~csum_fold(csum_partial(diff, sizeof(diff),
318 csum_unfold(*sum)));
319}
320EXPORT_SYMBOL(inet_proto_csum_replace4);
321
322void inet_proto_csum_replace16(__sum16 *sum, struct sk_buff *skb,
323 const __be32 *from, const __be32 *to,
324 int pseudohdr)
325{
326 __be32 diff[] = {
327 ~from[0], ~from[1], ~from[2], ~from[3],
328 to[0], to[1], to[2], to[3],
329 };
330 if (skb->ip_summed != CHECKSUM_PARTIAL) {
331 *sum = csum_fold(csum_partial(diff, sizeof(diff),
332 ~csum_unfold(*sum)));
333 if (skb->ip_summed == CHECKSUM_COMPLETE && pseudohdr)
334 skb->csum = ~csum_partial(diff, sizeof(diff),
335 ~skb->csum);
336 } else if (pseudohdr)
337 *sum = ~csum_fold(csum_partial(diff, sizeof(diff),
338 csum_unfold(*sum)));
339}
340EXPORT_SYMBOL(inet_proto_csum_replace16);
341
342struct __net_random_once_work {
343 struct work_struct work;
344 struct static_key *key;
345};
346
347static void __net_random_once_deferred(struct work_struct *w)
348{
349 struct __net_random_once_work *work =
350 container_of(w, struct __net_random_once_work, work);
351 BUG_ON(!static_key_enabled(work->key));
352 static_key_slow_dec(work->key);
353 kfree(work);
354}
355
356static void __net_random_once_disable_jump(struct static_key *key)
357{
358 struct __net_random_once_work *w;
359
360 w = kmalloc(sizeof(*w), GFP_ATOMIC);
361 if (!w)
362 return;
363
364 INIT_WORK(&w->work, __net_random_once_deferred);
365 w->key = key;
366 schedule_work(&w->work);
367}
368
369bool __net_get_random_once(void *buf, int nbytes, bool *done,
370 struct static_key *once_key)
371{
372 static DEFINE_SPINLOCK(lock);
373 unsigned long flags;
374
375 spin_lock_irqsave(&lock, flags);
376 if (*done) {
377 spin_unlock_irqrestore(&lock, flags);
378 return false;
379 }
380
381 get_random_bytes(buf, nbytes);
382 *done = true;
383 spin_unlock_irqrestore(&lock, flags);
384
385 __net_random_once_disable_jump(once_key);
386
387 return true;
388}
389EXPORT_SYMBOL(__net_get_random_once);
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 <linux/uaccess.h>
35
36DEFINE_RATELIMIT_STATE(net_ratelimit_state, 5 * HZ, 10);
37/*
38 * All net warning printk()s should be guarded by this function.
39 */
40int net_ratelimit(void)
41{
42 return __ratelimit(&net_ratelimit_state);
43}
44EXPORT_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
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}
75EXPORT_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
88static 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 */
120int 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 }
159cont:
160 if (i >= 4)
161 goto out;
162 s++;
163 srclen--;
164 }
165 ret = 1;
166 memcpy(dst, dbuf, sizeof(dbuf));
167out:
168 if (end)
169 *end = s;
170 return ret;
171}
172EXPORT_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 */
186int 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 }
271cont:
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;
296out:
297 if (end)
298 *end = s;
299 return ret;
300}
301EXPORT_SYMBOL(in6_pton);
302
303void 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}
317EXPORT_SYMBOL(inet_proto_csum_replace4);
318
319void inet_proto_csum_replace16(__sum16 *sum, struct sk_buff *skb,
320 const __be32 *from, const __be32 *to,
321 bool pseudohdr)
322{
323 __be32 diff[] = {
324 ~from[0], ~from[1], ~from[2], ~from[3],
325 to[0], to[1], to[2], to[3],
326 };
327 if (skb->ip_summed != CHECKSUM_PARTIAL) {
328 *sum = csum_fold(csum_partial(diff, sizeof(diff),
329 ~csum_unfold(*sum)));
330 if (skb->ip_summed == CHECKSUM_COMPLETE && pseudohdr)
331 skb->csum = ~csum_partial(diff, sizeof(diff),
332 ~skb->csum);
333 } else if (pseudohdr)
334 *sum = ~csum_fold(csum_partial(diff, sizeof(diff),
335 csum_unfold(*sum)));
336}
337EXPORT_SYMBOL(inet_proto_csum_replace16);
338
339void inet_proto_csum_replace_by_diff(__sum16 *sum, struct sk_buff *skb,
340 __wsum diff, bool pseudohdr)
341{
342 if (skb->ip_summed != CHECKSUM_PARTIAL) {
343 *sum = csum_fold(csum_add(diff, ~csum_unfold(*sum)));
344 if (skb->ip_summed == CHECKSUM_COMPLETE && pseudohdr)
345 skb->csum = ~csum_add(diff, ~skb->csum);
346 } else if (pseudohdr) {
347 *sum = ~csum_fold(csum_add(diff, csum_unfold(*sum)));
348 }
349}
350EXPORT_SYMBOL(inet_proto_csum_replace_by_diff);