#include "hash.h" #include /* 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; 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]); }