108 lines
3.1 KiB
C
108 lines
3.1 KiB
C
#include "dnssd_clientlib.h"
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#include "string.h"
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#include "malloc.h"
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void TXTRecordCreate(TXTRecordRef *txtRecord, uint16_t bufferLen, void *buffer)
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{
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txtRec->buffer = buffer;
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txtRec->buflen = buffer ? bufferLen : (uint16_t)0;
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txtRec->datalen = 0;
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txtRec->malloced = 0;
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}
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static uint8_t *InternalTXTRecordSearch
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(
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uint16_t txtLen,
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const void *txtRecord,
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const char *key,
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unsigned long *keylen
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)
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{
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uint8_t *p = (uint8_t *)txtRecord;
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uint8_t *e = p + txtLen;
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*keylen = (unsigned long) strlen(key);
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while (p < e) {
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uint8_t *x = p;
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p += 1 + p[0];
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if (p <= e && *keylen <= x[0] && !strncasecmp(key, (char *)x + 1, *keylen))
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if (*keylen == x[0] || x[1 + *keylen] == '=') {
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return (x);
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}
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}
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return (NULL);
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}
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DNSServiceErrorType TXTRecordRemoveValue(TXTRecordRef *txtRecord, const char *key)
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{
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unsigned long keylen, itemlen, remainder;
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uint8_t *item = InternalTXTRecordSearch(txtRec->datalen, txtRec->buffer, key, &keylen);
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if (!item) {
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return (kDNSServiceErr_NoSuchKey);
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}
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itemlen = (unsigned long)(1 + item[0]);
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remainder = (unsigned long)((txtRec->buffer + txtRec->datalen) - (item + itemlen));
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// Use memmove because memcpy behaviour is undefined for overlapping regions
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memmove(item, item + itemlen, remainder);
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txtRec->datalen -= itemlen;
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return (kDNSServiceErr_NoError);
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}
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DNSServiceErrorType TXTRecordSetValue(
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TXTRecordRef *txtRecord,
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const char *key,
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uint8_t valueSize,
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const void *value
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)
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{
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uint8_t *start, *p;
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const char *k;
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unsigned long keysize, keyvalsize;
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for (k = key; *k; k++) if (*k < 0x20 || *k > 0x7E || *k == '=') {
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return (kDNSServiceErr_Invalid);
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}
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keysize = (unsigned long)(k - key);
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keyvalsize = 1 + keysize + (value ? (1 + valueSize) : 0);
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if (keysize < 1 || keyvalsize > 255) {
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return (kDNSServiceErr_Invalid);
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}
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(void)TXTRecordRemoveValue(txtRecord, key);
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if (txtRec->datalen + keyvalsize > txtRec->buflen) {
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unsigned char *newbuf;
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unsigned long newlen = txtRec->datalen + keyvalsize;
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if (newlen > 0xFFFF) {
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return (kDNSServiceErr_Invalid);
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}
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newbuf = malloc((unsigned int)newlen);
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if (!newbuf) {
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return (kDNSServiceErr_NoMemory);
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}
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memcpy(newbuf, txtRec->buffer, txtRec->datalen);
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if (txtRec->malloced) {
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free(txtRec->buffer);
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}
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txtRec->buffer = newbuf;
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txtRec->buflen = (uint16_t)(newlen);
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txtRec->malloced = 1;
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}
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start = txtRec->buffer + txtRec->datalen;
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p = start + 1;
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memcpy(p, key, keysize);
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p += keysize;
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if (value) {
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*p++ = '=';
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memcpy(p, value, valueSize);
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p += valueSize;
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}
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*start = (uint8_t)(p - start - 1);
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txtRec->datalen += p - start;
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return (kDNSServiceErr_NoError);
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}
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void TXTRecordDeallocate(TXTRecordRef *txtRecord)
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{
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if (txtRec->malloced) {
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free(txtRec->buffer);
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}
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}
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