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27 * This file is part of the lwIP TCP/IP stack.
29 * Author: Adam Dunkels <adam@sics.se>
36 * Functions common to all TCP/IP modules, such as the Internet checksum and the
37 * byte order functions.
44 #include "lwip/arch.h"
47 #include "lwip/inet.h"
51 /* These are some reference implementations of the checksum algorithm, with the
52 * aim of being simple, correct and fully portable. Checksumming is the
53 * first thing you would want to optimize for your platform. If you create
54 * your own version, link it in and in your sys_arch.h put:
56 * #define LWIP_CHKSUM <your_checksum_routine>
59 #define LWIP_CHKSUM lwip_standard_chksum
65 * @param dataptr points to start of data to be summed at any boundary
66 * @param len length of data to be summed
67 * @return host order (!) lwip checksum (non-inverted Internet sum)
69 * @note accumulator size limits summable length to 64k
70 * @note host endianess is irrelevant (p3 RFC1071)
73 lwip_standard_chksum(void *dataptr, u16_t len)
80 /* dataptr may be at odd or even addresses */
81 octetptr = (u8_t*)dataptr;
84 /* declare first octet as most significant
85 thus assume network order, ignoring host order */
86 src = (*octetptr) << 8;
88 /* declare second octet as least significant */
96 /* accumulate remaining octet */
97 src = (*octetptr) << 8;
100 /* add deferred carry bits */
101 acc = (acc >> 16) + (acc & 0x0000ffffUL);
102 if ((acc & 0xffff0000) != 0) {
103 acc = (acc >> 16) + (acc & 0x0000ffffUL);
105 /* This maybe a little confusing: reorder sum using htons()
106 instead of ntohs() since it has a little less call overhead.
107 The caller must invert bits for Internet sum ! */
108 return htons((u16_t)acc);
112 #if 0 /* Version B */
118 * IP checksum two bytes at a time with support for
120 * Works for len up to and including 0x20000.
121 * by Curt McDowell, Broadcom Corp. 12/08/2005
125 lwip_standard_chksum(void *dataptr, int len)
130 int odd = ((u32_t)pb & 1);
132 /* Get aligned to u16_t */
133 if (odd && len > 0) {
134 ((u8_t *)&t)[1] = *pb++;
138 /* Add the bulk of the data */
145 /* Consume left-over byte, if any */
147 ((u8_t *)&t)[0] = *(u8_t *)ps;;
152 /* Fold 32-bit sum to 16 bits */
154 sum = (sum & 0xffff) + (sum >> 16);
156 /* Swap if alignment was odd */
158 sum = ((sum & 0xff) << 8) | ((sum & 0xff00) >> 8);
164 #if 0 /* Version C */
166 * An optimized checksum routine. Basically, it uses loop-unrolling on
167 * the checksum loop, treating the head and tail bytes specially, whereas
168 * the inner loop acts on 8 bytes at a time.
170 * @arg start of buffer to be checksummed. May be an odd byte address.
171 * @len number of bytes in the buffer to be checksummed.
173 * by Curt McDowell, Broadcom Corp. December 8th, 2005
177 lwip_standard_chksum(void *dataptr, int len)
183 /* starts at odd byte address? */
184 int odd = ((u32_t)pb & 1);
186 if (odd && len > 0) {
187 ((u8_t *)&t)[1] = *pb++;
193 if (((u32_t)ps & 3) && len > 1) {
201 tmp = sum + *pl++; /* ping */
203 tmp++; /* add back carry */
205 sum = tmp + *pl++; /* pong */
207 sum++; /* add back carry */
212 /* make room in upper bits */
213 sum = (sum >> 16) + (sum & 0xffff);
217 /* 16-bit aligned word remaining? */
223 /* dangling tail byte remaining? */
224 if (len > 0) /* include odd byte */
225 ((u8_t *)&t)[0] = *(u8_t *)ps;
227 sum += t; /* add end bytes */
229 while (sum >> 16) /* combine halves */
230 sum = (sum >> 16) + (sum & 0xffff);
233 sum = ((sum & 0xff) << 8) | ((sum & 0xff00) >> 8);
239 #endif /* LWIP_CHKSUM */
241 /* inet_chksum_pseudo:
243 * Calculates the pseudo Internet checksum used by TCP and UDP for a pbuf chain.
247 inet_chksum_pseudo(struct pbuf *p,
248 struct ip_addr *src, struct ip_addr *dest,
249 u8_t proto, u16_t proto_len)
257 /* iterate through all pbuf in chain */
258 for(q = p; q != NULL; q = q->next) {
259 LWIP_DEBUGF(INET_DEBUG, ("inet_chksum_pseudo(): checksumming pbuf %p (has next %p) \n",
260 (void *)q, (void *)q->next));
261 acc += LWIP_CHKSUM(q->payload, q->len);
262 /*LWIP_DEBUGF(INET_DEBUG, ("inet_chksum_pseudo(): unwrapped lwip_chksum()=%"X32_F" \n", acc));*/
264 acc = (acc & 0xffffUL) + (acc >> 16);
266 if (q->len % 2 != 0) {
267 swapped = 1 - swapped;
268 acc = ((acc & 0xff) << 8) | ((acc & 0xff00UL) >> 8);
270 /*LWIP_DEBUGF(INET_DEBUG, ("inet_chksum_pseudo(): wrapped lwip_chksum()=%"X32_F" \n", acc));*/
274 acc = ((acc & 0xff) << 8) | ((acc & 0xff00UL) >> 8);
276 acc += (src->addr & 0xffffUL);
277 acc += ((src->addr >> 16) & 0xffffUL);
278 acc += (dest->addr & 0xffffUL);
279 acc += ((dest->addr >> 16) & 0xffffUL);
280 acc += (u32_t)htons((u16_t)proto);
281 acc += (u32_t)htons(proto_len);
284 acc = (acc & 0xffffUL) + (acc >> 16);
286 LWIP_DEBUGF(INET_DEBUG, ("inet_chksum_pseudo(): pbuf chain lwip_chksum()=%"X32_F"\n", acc));
287 return (u16_t)~(acc & 0xffffUL);
292 * Calculates the Internet checksum over a portion of memory. Used primarily for IP
297 inet_chksum(void *dataptr, u16_t len)
301 acc = LWIP_CHKSUM(dataptr, len);
303 acc = (acc & 0xffff) + (acc >> 16);
305 return (u16_t)~(acc & 0xffff);
309 inet_chksum_pbuf(struct pbuf *p)
317 for(q = p; q != NULL; q = q->next) {
318 acc += LWIP_CHKSUM(q->payload, q->len);
320 acc = (acc & 0xffffUL) + (acc >> 16);
322 if (q->len % 2 != 0) {
323 swapped = 1 - swapped;
324 acc = (acc & 0x00ffUL << 8) | (acc & 0xff00UL >> 8);
329 acc = ((acc & 0x00ffUL) << 8) | ((acc & 0xff00UL) >> 8);
331 return (u16_t)~(acc & 0xffffUL);
334 /* Here for now until needed in other places in lwIP */
336 #define in_range(c, lo, up) ((u8_t)c >= lo && (u8_t)c <= up)
337 #define isprint(c) in_range(c, 0x20, 0x7f)
338 #define isdigit(c) in_range(c, '0', '9')
339 #define isxdigit(c) (isdigit(c) || in_range(c, 'a', 'f') || in_range(c, 'A', 'F'))
340 #define islower(c) in_range(c, 'a', 'z')
341 #define isspace(c) (c == ' ' || c == '\f' || c == '\n' || c == '\r' || c == '\t' || c == '\v')
345 * Ascii internet address interpretation routine.
346 * The value returned is in network order.
350 inet_addr(const char *cp)
354 if (inet_aton(cp, &val)) {
357 return (INADDR_NONE);
361 * Check whether "cp" is a valid ascii representation
362 * of an Internet address and convert to a binary address.
363 * Returns 1 if the address is valid, 0 if not.
364 * This replaces inet_addr, the return value from which
365 * cannot distinguish between failure and a local broadcast address.
368 inet_aton(const char *cp, struct in_addr *addr)
378 * Collect number up to ``.''.
379 * Values are specified as for C:
380 * 0x=hex, 0=octal, 1-9=decimal.
388 if (c == 'x' || c == 'X') {
396 val = (val * base) + (int)(c - '0');
398 } else if (base == 16 && isxdigit(c)) {
399 val = (val << 4) | (int)(c + 10 - (islower(c) ? 'a' : 'A'));
408 * a.b.c (with c treated as 16 bits)
409 * a.b (with b treated as 24 bits)
419 * Check for trailing characters.
421 if (c != '\0' && (!isprint(c) || !isspace(c)))
424 * Concoct the address according to
425 * the number of parts specified.
431 return (0); /* initial nondigit */
433 case 1: /* a -- 32 bits */
436 case 2: /* a.b -- 8.24 bits */
439 val |= parts[0] << 24;
442 case 3: /* a.b.c -- 8.8.16 bits */
445 val |= (parts[0] << 24) | (parts[1] << 16);
448 case 4: /* a.b.c.d -- 8.8.8.8 bits */
451 val |= (parts[0] << 24) | (parts[1] << 16) | (parts[2] << 8);
455 addr->s_addr = htonl(val);
459 /* Convert numeric IP address into decimal dotted ASCII representation.
460 * returns ptr to static buffer; not reentrant!
463 inet_ntoa(struct in_addr addr)
466 u32_t s_addr = addr.s_addr;
475 ap = (u8_t *)&s_addr;
476 for(n = 0; n < 4; n++) {
479 rem = *ap % (u8_t)10;
481 inv[i++] = '0' + rem;
493 * These are reference implementations of the byte swapping functions.
494 * Again with the aim of being simple, correct and fully portable.
495 * Byte swapping is the second thing you would want to optimize. You will
496 * need to port it to your architecture and in your cc.h:
498 * #define LWIP_PLATFORM_BYTESWAP 1
499 * #define LWIP_PLATFORM_HTONS(x) <your_htons>
500 * #define LWIP_PLATFORM_HTONL(x) <your_htonl>
502 * Note ntohs() and ntohl() are merely references to the htonx counterparts.
506 #error BYTE_ORDER is not defined
508 #if (LWIP_PLATFORM_BYTESWAP == 0) && (BYTE_ORDER == LITTLE_ENDIAN)
513 return ((n & 0xff) << 8) | ((n & 0xff00) >> 8);
525 return ((n & 0xff) << 24) |
526 ((n & 0xff00) << 8) |
527 ((n & 0xff0000) >> 8) |
528 ((n & 0xff000000) >> 24);
537 #endif /* (LWIP_PLATFORM_BYTESWAP == 0) && (BYTE_ORDER == LITTLE_ENDIAN) */