-// Check datagram for valid HMAC
-bool sptps_verify_datagram(sptps_t *s, const char *data, size_t len) {
- if(!s->instate || len < 21)
- return false;
-
- char buffer[len + 23];
- uint16_t netlen = htons(len - 21);
-
- memcpy(buffer, &netlen, 2);
- memcpy(buffer + 2, data, len);
-
- return digest_verify(&s->indigest, buffer, len - 14, buffer + len - 14);
-}
-
-// Receive incoming data, datagram version.
-static bool sptps_receive_data_datagram(sptps_t *s, const char *data, size_t len) {
- if(len < (s->instate ? 21 : 5))
- return error(s, EIO, "Received short packet");
-
- uint32_t seqno;
- memcpy(&seqno, data, 4);
- seqno = ntohl(seqno);
-
- if(!s->instate) {
- if(seqno != s->inseqno) {
- fprintf(stderr, "Received invalid packet seqno: %d != %d\n", seqno, s->inseqno);
- return error(s, EIO, "Invalid packet seqno");
- }
-
- s->inseqno = seqno + 1;
-
- uint8_t type = data[4];
-
- if(type != SPTPS_HANDSHAKE)
- return error(s, EIO, "Application record received before handshake finished");
-
- return receive_handshake(s, data + 5, len - 5);
- }
-