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knet_send_sync(3) Kronosnet Programmer's Manual knet_send_sync(3)


knet_send_sync - Synchronously send data to knet nodes.


#include <libknet.h>

int knet_send_sync(
    knet_handle_t  knet_h,
    const char    *buff,
    const size_t   buff_len,
    const int8_t   channel



knet_h - pointer to knet_handle_t

buff - pointer to the buffer of data to send

buff_len - length of data to send

channel - data channel to use (see knet_handle_add_datafd(3))

All knet RX/TX operations are async for performance reasons. There are applications that might need a sync version of data transmission and receive errors in case of failure to deliver to another host. knet_send_sync bypasses the whole TX async layer and delivers data directly to the link layer, and returns errors accordingly. knet_send_sync sends only one packet to one host at a time. It does NOT support multiple destinations or multicast packets. Decision is still based on dst_host_filter_fn.


knet_send_sync returns 0 on success and -1 on error. In addition to normal sendmmsg errors, knet_send_sync can fail due to: ECANCELED - data forward is disabled

EFAULT - dst_host_filter fatal error

EINVAL - dst_host_filter did not provide dst_host_ids_entries on unicast pckts

E2BIG - dst_host_filter did return more than one dst_host_ids_entries on unicast pckts

ENOMSG - received unknown message type

EHOSTDOWN - unicast pckt cannot be delivered because dest host is not connected yet

ECHILD - crypto failed

EAGAIN - sendmmsg was unable to send all messages and there was no progress during retry


knet_handle_remove_datafd(3), knet_handle_get_stats(3), knet_host_add(3), knet_handle_pmtud_setfreq(3), knet_handle_pmtud_get(3), knet_host_get_id_by_host_name(3), knet_host_get_status(3), knet_link_add_acl(3), knet_link_get_pong_count(3), knet_link_get_priority(3), knet_handle_free(3), knet_handle_enable_sock_notify(3), knet_handle_get_datafd(3), knet_recv(3), knet_link_get_ping_timers(3), knet_log_get_subsystem_id(3), knet_host_remove(3), knet_host_enable_status_change_notify(3), knet_strtoaddr(3), knet_link_rm_acl(3), knet_send(3), knet_handle_enable_pmtud_notify(3), knet_handle_get_transport_reconnect_interval(3), knet_link_get_enable(3), knet_link_set_priority(3), knet_log_set_loglevel(3), knet_handle_get_channel(3), knet_link_get_config(3), knet_link_get_link_list(3), knet_get_transport_list(3), knet_get_transport_id_by_name(3), knet_log_get_loglevel_id(3), knet_handle_new_ex(3), knet_host_set_name(3), knet_addrtostr(3), knet_handle_setfwd(3), knet_get_compress_list(3), knet_host_set_policy(3), knet_get_transport_name_by_id(3), knet_handle_enable_filter(3), knet_handle_compress(3), knet_link_get_status(3), knet_handle_add_datafd(3), knet_log_get_loglevel_name(3), knet_handle_enable_access_lists(3), knet_host_get_host_list(3), knet_host_get_policy(3), knet_link_set_enable(3), knet_link_set_pong_count(3), knet_log_get_subsystem_name(3), knet_host_get_name_by_host_id(3), knet_link_clear_config(3), knet_log_get_loglevel(3), knet_handle_new(3), knet_handle_pmtud_getfreq(3), knet_handle_pmtud_set(3), knet_handle_clear_stats(3), knet_link_set_config(3), knet_handle_crypto(3), knet_get_crypto_list(3), knet_handle_set_transport_reconnect_interval(3), knet_link_clear_acl(3), knet_link_set_ping_timers(3), knet_link_insert_acl(3)


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2020-04-23 kronosnet