stats: Only collect crypt over stats for received data packets

This is more for consistency really. The TX code only accumulates the
crypto overhead for data packets because it's not worth adding all the
accounting code around the ping/pong & pmtu transmitters.

libknet/threads_rx.c

@@ -236,6 +236,8 @@ static void _parse_recv_from_links(knet_handle_t knet_h, int sockfd, const struc
 	knet_node_id_t dst_host_ids[KNET_MAX_HOST];
 	size_t dst_host_ids_entries = 0;
 	int bcast = 1;
+	int was_decrypted = 0;
+	uint64_t crypt_time = 0;
 	struct timespec recvtime;
 	struct knet_header *inbuf = msg->msg_hdr.msg_iov->iov_base;
 	unsigned char *outbuf = (unsigned char *)msg->msg_hdr.msg_iov->iov_base;
@@ -250,7 +252,7 @@ static void _parse_recv_from_links(knet_handle_t knet_h, int sockfd, const struc
 	if (knet_h->crypto_instance) {
 		struct timespec start_time;
 		struct timespec end_time;
-		uint64_t crypt_time;
+
 
 		clock_gettime(CLOCK_MONOTONIC, &start_time);
 		if (crypto_authenticate_and_decrypt(knet_h,
@@ -270,13 +272,10 @@ static void _parse_recv_from_links(knet_handle_t knet_h, int sockfd, const struc
 		if (crypt_time > knet_h->stats.rx_crypt_time_max) {
 			knet_h->stats.rx_crypt_time_max = crypt_time;
 		}
-		knet_h->stats.rx_crypt_time_ave =
-			(knet_h->stats.rx_crypt_time_ave * knet_h->stats.rx_crypt_packets +
-			 crypt_time) / (knet_h->stats.rx_crypt_packets+1);
-		knet_h->stats.rx_crypt_packets++;
 
 		len = outlen;
 		inbuf = (struct knet_header *)knet_h->recv_from_links_buf_decrypt;
+		was_decrypted++;
 	}
 
 	if (len < (ssize_t)(KNET_HEADER_SIZE + 1)) {
@@ -420,6 +419,13 @@ static void _parse_recv_from_links(knet_handle_t knet_h, int sockfd, const struc
 			if (knet_h->enabled != 1) /* data forward is disabled */
 				break;
 
+			/* Only update the crypto overhead for data packets. Mainly to be
+			   consistent with TX */
+			knet_h->stats.rx_crypt_time_ave =
+				(knet_h->stats.rx_crypt_time_ave * knet_h->stats.rx_crypt_packets +
+				 crypt_time) / (knet_h->stats.rx_crypt_packets+1);
+			knet_h->stats.rx_crypt_packets++;
+
 			if (knet_h->dst_host_filter_fn) {
 				size_t host_idx;
 				int found = 0;