/*
	 * Copyright (C) 2012-2025 Red Hat, Inc.  All rights reserved.
	 *
	 * Authors: Fabio M. Di Nitto <fabbione@kronosnet.org>
	 *          Federico Simoncelli <fsimon@kronosnet.org>
	 *
	 * This software licensed under LGPL-2.0+
	 */
	
	#include "config.h"
	
	#include <stdio.h>
	#include <string.h>
	#include <errno.h>
	#include <sys/uio.h>
	#include <pthread.h>
	
	#include "compat.h"
	#include "compress.h"
	#include "crypto.h"
	#include "host.h"
	#include "links.h"
	#include "links_acl.h"
	#include "logging.h"
	#include "transports.h"
	#include "transport_common.h"
	#include "threads_common.h"
	#include "threads_heartbeat.h"
	#include "threads_rx.h"
	#include "netutils.h"
	
	/*
	 * RECV
	 */
	
	/*
	 *  return 1 if a > b
	 *  return -1 if b > a
	 *  return 0 if they are equal
	 */
	static inline int timecmp(struct timespec a, struct timespec b)
	{
		if (a.tv_sec != b.tv_sec) {
			if (a.tv_sec > b.tv_sec) {
				return 1;
			} else {
				return -1;
			}
		} else {
			if (a.tv_nsec > b.tv_nsec) {
				return 1;
			} else if (a.tv_nsec < b.tv_nsec) {
				return -1;
			} else {
				return 0;
			}
		}
	}
	
	/*
	 * this functions needs to return an index (0 to 7)
	 * to a knet_host_defrag_buf. (-1 on errors)
	 */
	
	static int find_pckt_defrag_buf(knet_handle_t knet_h, struct knet_header *inbuf)
	{
		struct knet_host *src_host = knet_h->host_index[inbuf->kh_node];
		int i, oldest;
	
		/*
		 * check if there is a buffer already in use handling the same seq_num
		 */
		for (i = 0; i < KNET_DEFRAG_BUFFERS; i++) {
			if (src_host->defrag_buf[i].in_use) {
				if (src_host->defrag_buf[i].pckt_seq == inbuf->khp_data_seq_num) {
					return i;
				}
			}
		}
	
		/*
		 * If there is no buffer that's handling the current seq_num
		 * either it's new or it's been reclaimed already.
		 * check if it's been reclaimed/seen before using the defrag circular
		 * buffer. If the pckt has been seen before, the buffer expired (ETIME)
		 * and there is no point to try to defrag it again.
		 */
		if (!_seq_num_lookup(src_host, inbuf->khp_data_seq_num, 1, 0)) {
			errno = ETIME;
			return -1;
		}
	
		/*
		 * register the pckt as seen
		 */
		_seq_num_set(src_host, inbuf->khp_data_seq_num, 1);
	
		/*
		 * see if there is a free buffer
		 */
		for (i = 0; i < KNET_DEFRAG_BUFFERS; i++) {
			if (!src_host->defrag_buf[i].in_use) {
				return i;
			}
		}
	
		/*
		 * at this point, there are no free buffers, the pckt is new
		 * and we need to reclaim a buffer, and we will take the one
		 * with the oldest timestamp. It's as good as any.
		 */
	
		oldest = 0;
	
		for (i = 0; i < KNET_DEFRAG_BUFFERS; i++) {
			if (timecmp(src_host->defrag_buf[i].last_update, src_host->defrag_buf[oldest].last_update) < 0) {
				oldest = i;
			}
		}
		src_host->defrag_buf[oldest].in_use = 0;
		return oldest;
	}
	
	static int pckt_defrag(knet_handle_t knet_h, struct knet_header *inbuf, ssize_t *len)
	{
		struct knet_host_defrag_buf *defrag_buf;
		int defrag_buf_idx;
	
		defrag_buf_idx = find_pckt_defrag_buf(knet_h, inbuf);
		if (defrag_buf_idx < 0) {
			return 1;
		}
	
		defrag_buf = &knet_h->host_index[inbuf->kh_node]->defrag_buf[defrag_buf_idx];
	
		/*
		 * if the buf is not is use, then make sure it's clean
		 */
		if (!defrag_buf->in_use) {
			memset(defrag_buf, 0, sizeof(struct knet_host_defrag_buf));
			defrag_buf->in_use = 1;
			defrag_buf->pckt_seq = inbuf->khp_data_seq_num;
		}
	
		/*
		 * update timestamp on the buffer
		 */
		clock_gettime(CLOCK_MONOTONIC, &defrag_buf->last_update);
	
		/*
		 * check if we already received this fragment
		 */
		if (defrag_buf->frag_map[inbuf->khp_data_frag_seq]) {
			/*
			 * if we have received this fragment and we didn't clear the buffer
			 * it means that we don't have all fragments yet
			 */
			return 1;
		}
	
		/*
		 *  we need to handle the last packet with gloves due to its different size
		 */
	
		if (inbuf->khp_data_frag_seq == inbuf->khp_data_frag_num) {
			defrag_buf->last_frag_size = *len;
	
			/*
			 * in the event when the last packet arrives first,
			 * we still don't know the offset vs the other fragments (based on MTU),
			 * so we store the fragment at the end of the buffer where it's safe
			 * and take a copy of the len so that we can restore its offset later.
			 * remember we can't use the local MTU for this calculation because pMTU
			 * can be asymettric between the same hosts.
			 */
			if (!defrag_buf->frag_size) {
				defrag_buf->last_first = 1;
				memmove(defrag_buf->buf + (KNET_MAX_PACKET_SIZE - *len),
				       inbuf->khp_data_userdata,
				       *len);
			}
		} else {
			defrag_buf->frag_size = *len;
		}
	
		if (defrag_buf->frag_size) {
			memmove(defrag_buf->buf + ((inbuf->khp_data_frag_seq - 1) * defrag_buf->frag_size),
			       inbuf->khp_data_userdata, *len);
		}
	
		defrag_buf->frag_recv++;
		defrag_buf->frag_map[inbuf->khp_data_frag_seq] = 1;
	
		/*
		 * check if we received all the fragments
		 */
		if (defrag_buf->frag_recv == inbuf->khp_data_frag_num) {
			/*
			 * special case the last pckt
			 */
	
			if (defrag_buf->last_first) {
				memmove(defrag_buf->buf + ((inbuf->khp_data_frag_num - 1) * defrag_buf->frag_size),
				        defrag_buf->buf + (KNET_MAX_PACKET_SIZE - defrag_buf->last_frag_size),
					defrag_buf->last_frag_size);
			}
	
			/*
			 * recalculate packet lenght
			 */
	
			*len = ((inbuf->khp_data_frag_num - 1) * defrag_buf->frag_size) + defrag_buf->last_frag_size;
	
			/*
			 * copy the pckt back in the user data
			 */
			memmove(inbuf->khp_data_userdata, defrag_buf->buf, *len);
	
			/*
			 * free this buffer
			 */
			defrag_buf->in_use = 0;
			return 0;
		}
	
		return 1;
	}
	
	/*
	 * processing incoming packets vs access lists
	 */
	static int _check_rx_acl(knet_handle_t knet_h, struct knet_link *src_link, const struct knet_mmsghdr *msg)
	{
		if (knet_h->use_access_lists) {
			if (!check_validate(knet_h, src_link, msg->msg_hdr.msg_name)) {
				char src_ipaddr[KNET_MAX_HOST_LEN];
				char src_port[KNET_MAX_PORT_LEN];
				
				memset(src_ipaddr, 0, KNET_MAX_HOST_LEN);
				memset(src_port, 0, KNET_MAX_PORT_LEN);
				if (knet_addrtostr(msg->msg_hdr.msg_name, sockaddr_len(msg->msg_hdr.msg_name),
						   src_ipaddr, KNET_MAX_HOST_LEN,
						   src_port, KNET_MAX_PORT_LEN) < 0) {
	
					log_warn(knet_h, KNET_SUB_RX, "Packet rejected: unable to resolve host/port");
				} else {
					log_warn(knet_h, KNET_SUB_RX, "Packet rejected from %s:%s", src_ipaddr, src_port);
				}
				return 0;
			}
		}
		return 1;
	}
	
	static int _fast_data_up(knet_handle_t knet_h, struct knet_host *src_host, struct knet_link *src_link)
	{
		if (src_link->received_pong) {
			log_debug(knet_h, KNET_SUB_RX, "host: %u link: %u received data during valid ping/pong activity. Force link up.", src_host->host_id, src_link->link_id);
			_link_updown(knet_h, src_host->host_id, src_link->link_id, src_link->status.enabled, 1, 0);
			return 1;
		}
		// host is not eligible for fast data up
		return 0;
	}
	
	static void _parse_recv_from_links(knet_handle_t knet_h, int sockfd, const struct knet_mmsghdr *msg)
	{
		int err = 0, savederrno = 0, stats_err = 0;
		ssize_t outlen;
		struct knet_host *src_host;
		struct knet_link *src_link;
		unsigned long long latency_last;
		knet_node_id_t dst_host_ids[KNET_MAX_HOST];
		size_t dst_host_ids_entries = 0;
		int bcast = 1;
		uint64_t decrypt_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;
		ssize_t len = msg->msg_len;
		struct iovec iov_out[1];
		int8_t channel;
		seq_num_t recv_seq_num;
		int wipe_bufs = 0;
		int try_decrypt = 0, decrypted = 0, i, found_link = 0;
	
		for (i = 1; i <= KNET_MAX_CRYPTO_INSTANCES; i++) {
			if (knet_h->crypto_instance[i]) {
				try_decrypt = 1;
				break;
			}
		}
	
		if ((!try_decrypt) && (knet_h->crypto_only == KNET_CRYPTO_RX_DISALLOW_CLEAR_TRAFFIC)) {
			log_debug(knet_h, KNET_SUB_RX, "RX thread configured to accept only crypto packets, but no crypto configs are configured!");
			return;
		}
	
		if (try_decrypt) {
			struct timespec start_time;
			struct timespec end_time;
	
			clock_gettime(CLOCK_MONOTONIC, &start_time);
			if (crypto_authenticate_and_decrypt(knet_h,
							    (unsigned char *)inbuf,
							    len,
							    knet_h->recv_from_links_buf_decrypt,
							    &outlen) < 0) {
				log_debug(knet_h, KNET_SUB_RX, "Unable to decrypt/auth packet");
				if (knet_h->crypto_only == KNET_CRYPTO_RX_DISALLOW_CLEAR_TRAFFIC) {
					char src_ipaddr[KNET_MAX_HOST_LEN];
					char src_port[KNET_MAX_PORT_LEN];
	
					memset(src_ipaddr, 0, KNET_MAX_HOST_LEN);
					memset(src_port, 0, KNET_MAX_PORT_LEN);
					if (knet_addrtostr(msg->msg_hdr.msg_name, sockaddr_len(msg->msg_hdr.msg_name),
							   src_ipaddr, KNET_MAX_HOST_LEN,
							   src_port, KNET_MAX_PORT_LEN) < 0) {
						log_err(knet_h, KNET_SUB_RX, "Unable to decrypt packet from unknown host/port (size %zu)!", len);
					} else {
						log_err(knet_h, KNET_SUB_RX, "Unable to decrypt packet from %s:%s (size %zu)!", src_ipaddr, src_port, len);
					}
					return;
				}
				log_debug(knet_h, KNET_SUB_RX, "Attempting to process packet as clear data");
			} else {
				clock_gettime(CLOCK_MONOTONIC, &end_time);
				timespec_diff(start_time, end_time, &decrypt_time);
	
				len = outlen;
				inbuf = (struct knet_header *)knet_h->recv_from_links_buf_decrypt;
				decrypted = 1;
			}
		}
	
		if (len < (ssize_t)(KNET_HEADER_SIZE + 1)) {
			log_debug(knet_h, KNET_SUB_RX, "Packet is too short: %ld", (long)len);
			return;
		}
	
		if (inbuf->kh_version != KNET_HEADER_VERSION) {
			log_debug(knet_h, KNET_SUB_RX, "Packet version does not match");
			return;
		}
	
		inbuf->kh_node = ntohs(inbuf->kh_node);
		src_host = knet_h->host_index[inbuf->kh_node];
		if (src_host == NULL) {  /* host not found */
			log_debug(knet_h, KNET_SUB_RX, "Unable to find source host for this packet");
			return;
		}
	
		if ((inbuf->kh_type & KNET_HEADER_TYPE_PMSK) != 0) {
			/* be aware this works only for PING / PONG and PMTUd packets! */
			src_link = src_host->link +
				(inbuf->khp_ping_link % KNET_MAX_LINK);
			if (!_check_rx_acl(knet_h, src_link, msg)) {
				return;
			}
			if (src_link->dynamic == KNET_LINK_DYNIP) {
				if (cmpaddr(&src_link->dst_addr, msg->msg_hdr.msg_name) != 0) {
					log_debug(knet_h, KNET_SUB_RX, "host: %u link: %u appears to have changed ip address",
						  src_host->host_id, src_link->link_id);
					memmove(&src_link->dst_addr, msg->msg_hdr.msg_name, sizeof(struct sockaddr_storage));
					if (knet_addrtostr(&src_link->dst_addr, sockaddr_len(&src_link->dst_addr),
							src_link->status.dst_ipaddr, KNET_MAX_HOST_LEN,
							src_link->status.dst_port, KNET_MAX_PORT_LEN) != 0) {
						log_debug(knet_h, KNET_SUB_RX, "Unable to resolve ???");
						snprintf(src_link->status.dst_ipaddr, KNET_MAX_HOST_LEN - 1, "Unknown!!!");
						snprintf(src_link->status.dst_port, KNET_MAX_PORT_LEN - 1, "??");
					} else {
						log_info(knet_h, KNET_SUB_RX,
							 "host: %u link: %u new connection established from: %s:%s",
							 src_host->host_id, src_link->link_id,
							 src_link->status.dst_ipaddr, src_link->status.dst_port);
					}
				}
				/*
				 * transport has already accepted the connection here
				 * otherwise we would not be receiving packets
				 */
				transport_link_dyn_connect(knet_h, sockfd, src_link);
			}
		} else { /* data packet */
			for (i = 0; i < KNET_MAX_LINK; i++) {
				src_link = &src_host->link[i];
				if (cmpaddr(&src_link->dst_addr, msg->msg_hdr.msg_name) == 0) {
					found_link = 1;
					break;
				}
			}
			if (found_link) {
				/*
				 * this check is currently redundant.. Keep it here for now
				 */
				if (!_check_rx_acl(knet_h, src_link, msg)) {
					return;
				}
			} else {
				log_debug(knet_h, KNET_SUB_RX, "Unable to determine source link for data packet. Discarding packet.");
				return;
			}
		}
	

		stats_err = pthread_mutex_lock(&src_link->link_stats_mutex);
		if (stats_err) {
			log_err(knet_h, KNET_SUB_RX, "Unable to get stats mutex lock for host %u link %u: %s",
				src_host->host_id, src_link->link_id, strerror(savederrno));
			return;
		}
	
		switch (inbuf->kh_type) {
		case KNET_HEADER_TYPE_DATA:
	
			/* data stats at the top for consistency with TX */
			src_link->status.stats.rx_data_packets++;
			src_link->status.stats.rx_data_bytes += len;
	
			if (decrypted) {
				stats_err = pthread_mutex_lock(&knet_h->handle_stats_mutex);
				if (stats_err < 0) {
					pthread_mutex_unlock(&src_link->link_stats_mutex);
					log_err(knet_h, KNET_SUB_RX, "Unable to get mutex lock: %s", strerror(stats_err));
					return;
				}
				/* Only update the crypto overhead for data packets. Mainly to be
				   consistent with TX */
				if (decrypt_time < knet_h->stats.rx_crypt_time_min) {
					knet_h->stats.rx_crypt_time_min = decrypt_time;
				}
				if (decrypt_time > knet_h->stats.rx_crypt_time_max) {
					knet_h->stats.rx_crypt_time_max = decrypt_time;
				}
				knet_h->stats.rx_crypt_time_ave =
					(knet_h->stats.rx_crypt_time_ave * knet_h->stats.rx_crypt_packets +
					 decrypt_time) / (knet_h->stats.rx_crypt_packets+1);
				knet_h->stats.rx_crypt_packets++;
				pthread_mutex_unlock(&knet_h->handle_stats_mutex);
			}
	
			if (!src_host->status.reachable) {
				if (!_fast_data_up(knet_h, src_host, src_link)) {
					pthread_mutex_unlock(&src_link->link_stats_mutex);
					log_debug(knet_h, KNET_SUB_RX, "Source host %u not reachable yet. Discarding packet.", src_host->host_id);
					return;
				}
			}
	
			inbuf->khp_data_seq_num = ntohs(inbuf->khp_data_seq_num);
			channel = inbuf->khp_data_channel;
			src_host->got_data = 1;
	
			if (!_seq_num_lookup(src_host, inbuf->khp_data_seq_num, 0, 0)) {
				pthread_mutex_unlock(&src_link->link_stats_mutex);
				if (src_host->link_handler_policy != KNET_LINK_POLICY_ACTIVE) {
					log_debug(knet_h, KNET_SUB_RX, "Packet has already been delivered");
				}
				return;
			}
	
			if (inbuf->khp_data_frag_num > 1) {
				/*
				 * len as received from the socket also includes extra stuff
				 * that the defrag code doesn't care about. So strip it
				 * here and readd only for repadding once we are done
				 * defragging
				 */
				len = len - KNET_HEADER_DATA_SIZE;
				if (pckt_defrag(knet_h, inbuf, &len)) {
					pthread_mutex_unlock(&src_link->link_stats_mutex);
					return;
				}
				len = len + KNET_HEADER_DATA_SIZE;
			}
	
			if (inbuf->khp_data_compress) {
				ssize_t decmp_outlen = KNET_DATABUFSIZE_COMPRESS;
				struct timespec start_time;
				struct timespec end_time;
				uint64_t compress_time;
	
				clock_gettime(CLOCK_MONOTONIC, &start_time);
				err = decompress(knet_h, inbuf->khp_data_compress,
						 (const unsigned char *)inbuf->khp_data_userdata,
						 len - KNET_HEADER_DATA_SIZE,
						 knet_h->recv_from_links_buf_decompress,
						 &decmp_outlen);
	
				stats_err = pthread_mutex_lock(&knet_h->handle_stats_mutex);
				if (stats_err < 0) {
					pthread_mutex_unlock(&src_link->link_stats_mutex);
					log_err(knet_h, KNET_SUB_RX, "Unable to get mutex lock: %s", strerror(stats_err));
					return;
				}
	
				clock_gettime(CLOCK_MONOTONIC, &end_time);
				timespec_diff(start_time, end_time, &compress_time);
	
				if (!err) {
					/* Collect stats */
					if (compress_time < knet_h->stats.rx_compress_time_min) {
						knet_h->stats.rx_compress_time_min = compress_time;
					}
					if (compress_time > knet_h->stats.rx_compress_time_max) {
						knet_h->stats.rx_compress_time_max = compress_time;
					}
					knet_h->stats.rx_compress_time_ave =
						(knet_h->stats.rx_compress_time_ave * knet_h->stats.rx_compressed_packets +
						 compress_time) / (knet_h->stats.rx_compressed_packets+1);
	
					knet_h->stats.rx_compressed_packets++;
					knet_h->stats.rx_compressed_original_bytes += decmp_outlen;
					knet_h->stats.rx_compressed_size_bytes += len - KNET_HEADER_SIZE;
	
					memmove(inbuf->khp_data_userdata, knet_h->recv_from_links_buf_decompress, decmp_outlen);
					len = decmp_outlen + KNET_HEADER_DATA_SIZE;
				} else {
					pthread_mutex_unlock(&knet_h->handle_stats_mutex);
					pthread_mutex_unlock(&src_link->link_stats_mutex);
					log_err(knet_h, KNET_SUB_COMPRESS, "Unable to decompress packet (%d): %s",
						err, strerror(errno));
					return;
				}
				pthread_mutex_unlock(&knet_h->handle_stats_mutex);
			}
	
			if (knet_h->enabled != 1) /* data forward is disabled */
				break;
	
			if (knet_h->dst_host_filter_fn) {
				size_t host_idx;
				int found = 0;
	
				bcast = knet_h->dst_host_filter_fn(
						knet_h->dst_host_filter_fn_private_data,
						(const unsigned char *)inbuf->khp_data_userdata,
						len - KNET_HEADER_DATA_SIZE,
						KNET_NOTIFY_RX,
						knet_h->host_id,
						inbuf->kh_node,
						&channel,
						dst_host_ids,
						&dst_host_ids_entries);
				if (bcast < 0) {
					pthread_mutex_unlock(&src_link->link_stats_mutex);
					log_debug(knet_h, KNET_SUB_RX, "Error from dst_host_filter_fn: %d", bcast);
					return;
				}
	
				if ((!bcast) && (!dst_host_ids_entries)) {
					pthread_mutex_unlock(&src_link->link_stats_mutex);
					log_debug(knet_h, KNET_SUB_RX, "Message is unicast but no dst_host_ids_entries");
					return;
				}
	
				/* check if we are dst for this packet */
				if (!bcast) {
					if (dst_host_ids_entries > KNET_MAX_HOST) {
						pthread_mutex_unlock(&src_link->link_stats_mutex);
						log_debug(knet_h, KNET_SUB_RX, "dst_host_filter_fn returned too many destinations");
						return;
					}
					for (host_idx = 0; host_idx < dst_host_ids_entries; host_idx++) {
						if (dst_host_ids[host_idx] == knet_h->host_id) {
							found = 1;
							break;
						}
					}
					if (!found) {
						pthread_mutex_unlock(&src_link->link_stats_mutex);
						log_debug(knet_h, KNET_SUB_RX, "Packet is not for us");
						return;
					}
				}
			}
	
			if (!knet_h->sockfd[channel].in_use) {
				pthread_mutex_unlock(&src_link->link_stats_mutex);
				log_debug(knet_h, KNET_SUB_RX,
					  "received packet for channel %d but there is no local sock connected",
					  channel);
				return;
			}
	
			outlen = 0;
			memset(iov_out, 0, sizeof(iov_out));
	
	retry:
			iov_out[0].iov_base = (void *) inbuf->khp_data_userdata + outlen;
			iov_out[0].iov_len = len - (outlen + KNET_HEADER_DATA_SIZE);
	
			outlen = writev(knet_h->sockfd[channel].sockfd[knet_h->sockfd[channel].is_created], iov_out, 1);
			if ((outlen > 0) && (outlen < (ssize_t)iov_out[0].iov_len)) {
				log_debug(knet_h, KNET_SUB_RX,
					  "Unable to send all data to the application in one go. Expected: %zu Sent: %zd\n",
					  iov_out[0].iov_len, outlen);
				goto retry;
			}
	
			if (outlen <= 0) {
				knet_h->sock_notify_fn(knet_h->sock_notify_fn_private_data,
						       knet_h->sockfd[channel].sockfd[0],
						       channel,
						       KNET_NOTIFY_RX,
						       outlen,
						       errno);
				pthread_mutex_unlock(&src_link->link_stats_mutex);
				return;
			}
			if ((size_t)outlen == iov_out[0].iov_len) {
				_seq_num_set(src_host, inbuf->khp_data_seq_num, 0);
			}
			break;
		case KNET_HEADER_TYPE_PING:
			outlen = KNET_HEADER_PING_SIZE;
			inbuf->kh_type = KNET_HEADER_TYPE_PONG;
			inbuf->kh_node = htons(knet_h->host_id);
			recv_seq_num = ntohs(inbuf->khp_ping_seq_num);
			src_link->status.stats.rx_ping_packets++;
			src_link->status.stats.rx_ping_bytes += len;
	
			wipe_bufs = 0;
	
			if (!inbuf->khp_ping_timed) {
				/*
				 * we might be receiving this message from all links, but we want
				 * to process it only the first time
				 */
				if (recv_seq_num != src_host->untimed_rx_seq_num) {
					/*
					 * cache the untimed seq num
					 */
					src_host->untimed_rx_seq_num = recv_seq_num;
					/*
					 * if the host has received data in between
					 * untimed ping, then we don't need to wipe the bufs
					 */
					if (src_host->got_data) {
						src_host->got_data = 0;
						wipe_bufs = 0;
					} else {
						wipe_bufs = 1;
					}
				}
				_seq_num_lookup(src_host, recv_seq_num, 0, wipe_bufs);
			} else {
				/*
				 * pings always arrives in bursts over all the link
				 * catch the first of them to cache the seq num and
				 * avoid duplicate processing
				 */
				if (recv_seq_num != src_host->timed_rx_seq_num) {
					src_host->timed_rx_seq_num = recv_seq_num;
	
					if (recv_seq_num == 0) {
						_seq_num_lookup(src_host, recv_seq_num, 0, 1);
					}
				}
			}
	
			if (knet_h->crypto_in_use_config) {
				if (crypto_encrypt_and_sign(knet_h,
							    (const unsigned char *)inbuf,
							    outlen,
							    knet_h->recv_from_links_buf_crypt,
							    &outlen) < 0) {
					log_debug(knet_h, KNET_SUB_RX, "Unable to encrypt pong packet");
					break;
				}
				outbuf = knet_h->recv_from_links_buf_crypt;
				stats_err = pthread_mutex_lock(&knet_h->handle_stats_mutex);
				if (stats_err < 0) {
					log_err(knet_h, KNET_SUB_RX, "Unable to get mutex lock: %s", strerror(stats_err));
					break;
				}
				knet_h->stats_extra.tx_crypt_pong_packets++;
				pthread_mutex_unlock(&knet_h->handle_stats_mutex);
			}
	
	retry_pong:
			if (src_link->transport_connected) {
				if (transport_get_connection_oriented(knet_h, src_link->transport) == TRANSPORT_PROTO_NOT_CONNECTION_ORIENTED) {
					len = sendto(src_link->outsock, outbuf, outlen, MSG_DONTWAIT | MSG_NOSIGNAL,
						     (struct sockaddr *) &src_link->dst_addr, knet_h->knet_transport_fd_tracker[src_link->outsock].sockaddr_len);
				} else {
					len = sendto(src_link->outsock, outbuf, outlen, MSG_DONTWAIT | MSG_NOSIGNAL, NULL, 0);
				}
				savederrno = errno;
				if (len != outlen) {
					err = transport_tx_sock_error(knet_h, src_link->transport, src_link->outsock, KNET_SUB_RX, len, savederrno);
					switch(err) {
						case -1: /* unrecoverable error */
							log_debug(knet_h, KNET_SUB_RX,
								  "Unable to send pong reply (sock: %d) packet (sendto): %d %s. recorded src ip: %s src port: %s dst ip: %s dst port: %s",
								  src_link->outsock, errno, strerror(errno),
								  src_link->status.src_ipaddr, src_link->status.src_port,
								  src_link->status.dst_ipaddr, src_link->status.dst_port);
							src_link->status.stats.tx_pong_errors++;
							break;
						case 0: /* ignore error and continue */
							break;
						case 1: /* retry to send those same data */
							src_link->status.stats.tx_pong_retries++;
							goto retry_pong;
							break;
					}
				}
				src_link->status.stats.tx_pong_packets++;
				src_link->status.stats.tx_pong_bytes += outlen;
			}
			break;
		case KNET_HEADER_TYPE_PONG:
			src_link->status.stats.rx_pong_packets++;
			src_link->status.stats.rx_pong_bytes += len;
			clock_gettime(CLOCK_MONOTONIC, &src_link->status.pong_last);
	
			memmove(&recvtime, &inbuf->khp_ping_time[0], sizeof(struct timespec));
			timespec_diff(recvtime,
					src_link->status.pong_last, &latency_last);
	
			if ((latency_last / 1000llu) > src_link->pong_timeout) {
				log_debug(knet_h, KNET_SUB_RX,
					  "Incoming pong packet from host: %u link: %u has higher latency than pong_timeout. Discarding",
					  src_host->host_id, src_link->link_id);
			} else {
	
				/*
				 * in words : ('previous mean' * '(count -1)') + 'new value') / 'count'
				 */
	
				src_link->latency_cur_samples++;
	
				/*
				 * limit to max_samples (precision)
				 */
				if (src_link->latency_cur_samples >= src_link->latency_max_samples) {
					src_link->latency_cur_samples = src_link->latency_max_samples;
				}

				src_link->status.latency =
					(((src_link->status.latency * (src_link->latency_cur_samples - 1)) + (latency_last / 1000llu)) / src_link->latency_cur_samples);
	
				if (src_link->status.latency < src_link->pong_timeout_adj) {
					if (!src_link->status.connected) {
						if (src_link->received_pong >= src_link->pong_count) {
							log_info(knet_h, KNET_SUB_RX, "host: %u link: %u is up",
								 src_host->host_id, src_link->link_id);
							_link_updown(knet_h, src_host->host_id, src_link->link_id, src_link->status.enabled, 1, 0);
						} else {
							src_link->received_pong++;
							log_debug(knet_h, KNET_SUB_RX, "host: %u link: %u received pong: %u",
								  src_host->host_id, src_link->link_id, src_link->received_pong);
						}
					}
				}
				/* Calculate latency stats */
				if (src_link->status.latency > src_link->status.stats.latency_max) {
					src_link->status.stats.latency_max = src_link->status.latency;
				}
				if (src_link->status.latency < src_link->status.stats.latency_min) {
					src_link->status.stats.latency_min = src_link->status.latency;
				}
	
				/*
				 * those 2 lines below make all latency average calculations consistent and capped to
				 * link precision. In future we will kill the one above to keep only this one in
				 * the stats structure, but for now we leave it around to avoid API/ABI
				 * breakage as we backport the fixes to stable
				 */
				src_link->status.stats.latency_ave = src_link->status.latency;
				src_link->status.stats.latency_samples = src_link->latency_cur_samples;
			}
			break;
		case KNET_HEADER_TYPE_PMTUD:
			src_link->status.stats.rx_pmtu_packets++;
			src_link->status.stats.rx_pmtu_bytes += len;
			outlen = KNET_HEADER_PMTUD_SIZE;
			inbuf->kh_type = KNET_HEADER_TYPE_PMTUD_REPLY;
			inbuf->kh_node = htons(knet_h->host_id);
	
			if (knet_h->crypto_in_use_config) {
				if (crypto_encrypt_and_sign(knet_h,
							    (const unsigned char *)inbuf,
							    outlen,
							    knet_h->recv_from_links_buf_crypt,
							    &outlen) < 0) {
					log_debug(knet_h, KNET_SUB_RX, "Unable to encrypt PMTUd reply packet");
					break;
				}
				outbuf = knet_h->recv_from_links_buf_crypt;
				stats_err = pthread_mutex_lock(&knet_h->handle_stats_mutex);
				if (stats_err < 0) {
					log_err(knet_h, KNET_SUB_RX, "Unable to get mutex lock: %s", strerror(stats_err));
					break;
				}
				knet_h->stats_extra.tx_crypt_pmtu_reply_packets++;
				pthread_mutex_unlock(&knet_h->handle_stats_mutex);
			}
	
			/* Unlock so we don't deadlock with tx_mutex */
			pthread_mutex_unlock(&src_link->link_stats_mutex);
	
			savederrno = pthread_mutex_lock(&knet_h->tx_mutex);
			if (savederrno) {
				log_err(knet_h, KNET_SUB_RX, "Unable to get TX mutex lock: %s", strerror(savederrno));
				goto out_pmtud;
			}
	retry_pmtud:
			if (src_link->transport_connected) {
				if (transport_get_connection_oriented(knet_h, src_link->transport) == TRANSPORT_PROTO_NOT_CONNECTION_ORIENTED) {
					len = sendto(src_link->outsock, outbuf, outlen, MSG_DONTWAIT | MSG_NOSIGNAL,
						     (struct sockaddr *) &src_link->dst_addr, knet_h->knet_transport_fd_tracker[src_link->outsock].sockaddr_len);
				} else {
					len = sendto(src_link->outsock, outbuf, outlen, MSG_DONTWAIT | MSG_NOSIGNAL, NULL, 0);
				}
				savederrno = errno;
				if (len != outlen) {
					err = transport_tx_sock_error(knet_h, src_link->transport, src_link->outsock, KNET_SUB_RX, len, savederrno);
					stats_err = pthread_mutex_lock(&src_link->link_stats_mutex);
					if (stats_err < 0) {
						log_err(knet_h, KNET_SUB_RX, "Unable to get mutex lock: %s", strerror(stats_err));
						break;
					}
					switch(err) {
						case -1: /* unrecoverable error */
							log_debug(knet_h, KNET_SUB_RX,
								  "Unable to send PMTUd reply (sock: %d) packet (sendto): %d %s. recorded src ip: %s src port: %s dst ip: %s dst port: %s",
								  src_link->outsock, errno, strerror(errno),
								  src_link->status.src_ipaddr, src_link->status.src_port,
								  src_link->status.dst_ipaddr, src_link->status.dst_port);
	
							src_link->status.stats.tx_pmtu_errors++;
							break;
						case 0: /* ignore error and continue */
							src_link->status.stats.tx_pmtu_errors++;
							break;
						case 1: /* retry to send those same data */
							src_link->status.stats.tx_pmtu_retries++;
							pthread_mutex_unlock(&src_link->link_stats_mutex);
							goto retry_pmtud;
							break;
					}
					pthread_mutex_unlock(&src_link->link_stats_mutex);
				}
			}
			pthread_mutex_unlock(&knet_h->tx_mutex);
	out_pmtud:
			return; /* Don't need to unlock link_stats_mutex */
		case KNET_HEADER_TYPE_PMTUD_REPLY:
			src_link->status.stats.rx_pmtu_packets++;
			src_link->status.stats.rx_pmtu_bytes += len;
	
			/* pmtud_mutex can't be acquired while we hold a link_stats_mutex (ordering) */
			pthread_mutex_unlock(&src_link->link_stats_mutex);
	
			if (pthread_mutex_lock(&knet_h->pmtud_mutex) != 0) {
				log_debug(knet_h, KNET_SUB_RX, "Unable to get mutex lock");
				break;
			}
			src_link->last_recv_mtu = inbuf->khp_pmtud_size;
			pthread_cond_signal(&knet_h->pmtud_cond);
			pthread_mutex_unlock(&knet_h->pmtud_mutex);
			return;
		default:
			pthread_mutex_unlock(&src_link->link_stats_mutex);
			return;
		}
		pthread_mutex_unlock(&src_link->link_stats_mutex);
	}
	
	static void _handle_recv_from_links(knet_handle_t knet_h, int sockfd, struct knet_mmsghdr *msg)
	{
		int err, savederrno;
		int i, msg_recv, transport;
	
		if (pthread_rwlock_rdlock(&knet_h->global_rwlock) != 0) {
			log_debug(knet_h, KNET_SUB_RX, "Unable to get global read lock");
			return;
		}
	
		if (_is_valid_fd(knet_h, sockfd) < 1) {
			/*
			 * this is normal if a fd got an event and before we grab the read lock
			 * and the link is removed by another thread
			 */
			goto exit_unlock;
		}
	
		transport = knet_h->knet_transport_fd_tracker[sockfd].transport;
	
		/*
		 * reset msg_namelen to buffer size because after recvmmsg
		 * each msg_namelen will contain sizeof sockaddr_in or sockaddr_in6
		 */
	
		for (i = 0; i < PCKT_RX_BUFS; i++) {
			msg[i].msg_hdr.msg_namelen = knet_h->knet_transport_fd_tracker[sockfd].sockaddr_len;
		}
	
		msg_recv = _recvmmsg(sockfd, &msg[0], PCKT_RX_BUFS, MSG_DONTWAIT | MSG_NOSIGNAL);
		savederrno = errno;
	
		/*
		 * WARNING: man page for recvmmsg is wrong. Kernel implementation here:
		 * recvmmsg can return:
		 * -1 on error
		 *  0 if the previous run of recvmmsg recorded an error on the socket
		 *  N number of messages (see exception below).
		 *
		 * If there is an error from recvmsg after receiving a frame or more, the recvmmsg
		 * loop is interrupted, error recorded in the socket (getsockopt(SO_ERROR) and
		 * it will be visibile in the next run.
		 *
		 * Need to be careful how we handle errors at this stage.
		 *
		 * error messages need to be handled on a per transport/protocol base
		 * at this point we have different layers of error handling
		 * - msg_recv < 0 -> error from this run
		 *   msg_recv = 0 -> error from previous run and error on socket needs to be cleared
		 * - per-transport message data
		 *   example: msg[i].msg_hdr.msg_flags & MSG_NOTIFICATION or msg_len for SCTP == EOF,
		 *            but for UDP it is perfectly legal to receive a 0 bytes message.. go figure
		 * - NOTE: on SCTP MSG_NOTIFICATION we get msg_recv == PCKT_FRAG_MAX messages and no
		 *         errno set. That means the error api needs to be able to abort the loop below.
		 */
	
		if (msg_recv <= 0) {
			transport_rx_sock_error(knet_h, transport, sockfd, msg_recv, savederrno);
			goto exit_unlock;
		}
	
		for (i = 0; i < msg_recv; i++) {
			err = transport_rx_is_data(knet_h, transport, sockfd, &msg[i]);
	
			/*
			 * TODO: make this section silent once we are confident
			 *       all protocols packet handlers are good
			 */
	
			switch(err) {
				case KNET_TRANSPORT_RX_ERROR: /* on error */
					log_debug(knet_h, KNET_SUB_RX, "Transport reported error parsing packet");
					goto exit_unlock;
					break;
				case KNET_TRANSPORT_RX_NOT_DATA_CONTINUE: /* packet is not data and we should continue the packet process loop */
					log_debug(knet_h, KNET_SUB_RX, "Transport reported no data, continue");
					break;
				case KNET_TRANSPORT_RX_NOT_DATA_STOP: /* packet is not data and we should STOP the packet process loop */
					log_debug(knet_h, KNET_SUB_RX, "Transport reported no data, stop");
					goto exit_unlock;
					break;
				case KNET_TRANSPORT_RX_IS_DATA: /* packet is data and should be parsed as such */
					_parse_recv_from_links(knet_h, sockfd, &msg[i]);
					break;
				case KNET_TRANSPORT_RX_OOB_DATA_CONTINUE:
					log_debug(knet_h, KNET_SUB_RX, "Transport is processing sock OOB data, continue");
					break;
				case KNET_TRANSPORT_RX_OOB_DATA_STOP:
					log_debug(knet_h, KNET_SUB_RX, "Transport has completed processing sock OOB data, stop");
					goto exit_unlock;
					break;
			}
		}
	
	exit_unlock:
		pthread_rwlock_unlock(&knet_h->global_rwlock);
	}
	
	void *_handle_recv_from_links_thread(void *data)
	{
		int i, nev;
		knet_handle_t knet_h = (knet_handle_t) data;
		struct epoll_event events[KNET_EPOLL_MAX_EVENTS];
		struct sockaddr_storage address[PCKT_RX_BUFS];
		struct knet_mmsghdr msg[PCKT_RX_BUFS];
		struct iovec iov_in[PCKT_RX_BUFS];
	#if defined(IP_PKTINFO) || defined(IPV6_PKTINFO)
		unsigned char control_in[PCKT_RX_BUFS][CMSG_SPACE(sizeof(struct in6_pktinfo))];
	#endif
	
		set_thread_status(knet_h, KNET_THREAD_RX, KNET_THREAD_STARTED);
	
		memset(&msg, 0, sizeof(msg));
		memset(&events, 0, sizeof(events));
	
		for (i = 0; i < PCKT_RX_BUFS; i++) {
			iov_in[i].iov_base = (void *)knet_h->recv_from_links_buf[i];
			iov_in[i].iov_len = KNET_DATABUFSIZE;
	
			memset(&msg[i].msg_hdr, 0, sizeof(struct msghdr));
	
			msg[i].msg_hdr.msg_name = &address[i];
			msg[i].msg_hdr.msg_namelen = sizeof(struct sockaddr_storage); /* Real value filled in before actual use */
			msg[i].msg_hdr.msg_iov = &iov_in[i];
			msg[i].msg_hdr.msg_iovlen = 1;
	#if defined(IP_PKTINFO) || defined(IPV6_PKTINFO)
			msg[i].msg_hdr.msg_control = &control_in[i][0];
			msg[i].msg_hdr.msg_controllen = CMSG_SPACE(sizeof(struct in6_pktinfo)); /* Largest of the two pktinfo structs */
	#endif
		}
	
		while (!shutdown_in_progress(knet_h)) {
			nev = epoll_wait(knet_h->recv_from_links_epollfd, events, KNET_EPOLL_MAX_EVENTS, KNET_THREADS_TIMERES / 1000);
	
			/*
			 * the RX threads only need to notify that there has been at least
			 * one successful run after queue flush has been requested.
			 * See setfwd in handle.c
			 */
			if (get_thread_flush_queue(knet_h, KNET_THREAD_RX) == KNET_THREAD_QUEUE_FLUSH) {
				set_thread_flush_queue(knet_h, KNET_THREAD_RX, KNET_THREAD_QUEUE_FLUSHED);
			}
	
			/*
			 * we use timeout to detect if thread is shutting down
			 */
			if (nev == 0) {
				continue;
			}
	
			for (i = 0; i < nev; i++) {
				_handle_recv_from_links(knet_h, events[i].data.fd, msg);
			}
		}
	
		set_thread_status(knet_h, KNET_THREAD_RX, KNET_THREAD_STOPPED);
	
		return NULL;
	}
	
	ssize_t knet_recv(knet_handle_t knet_h, char *buff, const size_t buff_len, const int8_t channel)
	{
		int savederrno = 0;
		ssize_t err = 0;
		struct iovec iov_in;
	
		if (!_is_valid_handle(knet_h)) {
			return -1;
		}
	
		if (buff == NULL) {
			errno = EINVAL;
			return -1;
		}
	
		if (buff_len <= 0) {
			errno = EINVAL;
			return -1;
		}
	
		if (buff_len > KNET_MAX_PACKET_SIZE) {
			errno = EINVAL;
			return -1;
		}
	
		if (channel < 0) {
			errno = EINVAL;
			return -1;
		}
	
		if (channel >= KNET_DATAFD_MAX) {
			errno = EINVAL;
			return -1;
		}
	
		savederrno = pthread_rwlock_rdlock(&knet_h->global_rwlock);
		if (savederrno) {
			log_err(knet_h, KNET_SUB_HANDLE, "Unable to get read lock: %s",
				strerror(savederrno));
			errno = savederrno;
			return -1;
		}
	
		if (!knet_h->sockfd[channel].in_use) {
			savederrno = EINVAL;
			err = -1;
			goto out_unlock;
		}
	
		memset(&iov_in, 0, sizeof(iov_in));
		iov_in.iov_base = (void *)buff;
		iov_in.iov_len = buff_len;
	
		err = readv(knet_h->sockfd[channel].sockfd[0], &iov_in, 1);
		savederrno = errno;
	
	out_unlock:
		pthread_rwlock_unlock(&knet_h->global_rwlock);
		errno = err ? savederrno : 0;
		return err;
	}