+/**
+ * get_packetid - Given a PGP packet returns the keyid.
+ * @packet: The packet to calculate the id for.
+ */
+uint64_t get_packetid(struct openpgp_packet *packet)
+{
+ uint64_t keyid = 0;
+ int offset = 0;
+ int i = 0;
+ size_t length = 0;
+ unsigned char buff[20];
+
+ assert(packet != NULL);
+
+ switch (packet->data[0]) {
+ case 2:
+ case 3:
+ /*
+ * For a type 2 or 3 key the keyid is the last 64 bits of the
+ * public modulus n, which is stored as an MPI from offset 8
+ * onwards.
+ */
+ offset = (packet->data[8] << 8) +
+ packet->data[9];
+ offset = ((offset + 7) / 8) + 2;
+
+ for (keyid = 0, i = 0; i < 8; i++) {
+ keyid <<= 8;
+ keyid += packet->data[offset++];
+ }
+ /*
+ * Check for an RSA key; if not then log but accept anyway.
+ * 1 == RSA
+ * 2 == RSA Encrypt-Only
+ * 3 == RSA Sign-Only
+ */
+ if (packet->data[7] < 1 || packet->data[7] > 3) {
+ logthing(LOGTHING_NOTICE,
+ "Type 2 or 3 key, but not RSA: %llx (type %d)",
+ keyid,
+ packet->data[7]);
+ }
+ break;
+ case 4:
+ get_fingerprint(packet, buff, &length);