123456789101112131415161718192021222324252627282930 |
- #include "hash.h"
- #include "c_string.h"
- /* Caution: When changing this, update COAP_DEFAULT_WKC_HASHKEY
- * accordingly (see int coap_hash_path());
- */
- void coap_hash(const unsigned char *s, unsigned int len, coap_key_t h) {
- size_t j;
- while (len--) {
- j = sizeof(coap_key_t)-1;
- while (j) {
- h[j] = ((h[j] << 7) | (h[j-1] >> 1)) + h[j];
- --j;
- }
- h[0] = (h[0] << 7) + h[0] + *s++;
- }
- }
- void coap_transaction_id(const uint32_t ip, const uint32_t port, const coap_packet_t *pkt, coap_tid_t *id) {
- coap_key_t h;
- c_memset(h, 0, sizeof(coap_key_t));
- /* Compare the transport address. */
- coap_hash((const unsigned char *)&(port), sizeof(port), h);
- coap_hash((const unsigned char *)&(ip), sizeof(ip), h);
- coap_hash((const unsigned char *)(pkt->hdr.id), sizeof(pkt->hdr.id), h);
- *id = ((h[0] << 8) | h[1]) ^ ((h[2] << 8) | h[3]);
- }
|