1KNET_HANDLE_ADD_DATAFD(3)Kronosnet Programmer's ManualKNET_HANDLE_ADD_DATAFD(3)
2
6 knet_handle_add_datafd - Install a file descriptor for communication.
7
9 #include <libknet.h>
10 int knet_handle_add_datafd(
12 knet_handle_t knet_h,
13 int *datafd,
14 int8_t *channel
15 );
16
18 knet_handle_add_datafd
19 IMPORTANT: In order to add datafd to knet, knet_han‐
21 dle_enable_sock_notify MUST be set and be able to handle both errors
22 (-1) and 0 bytes read / write from the provided datafd. On read error
23 (< 0) from datafd, the socket is automatically removed from polling to
24 avoid spinning on dead sockets. It is safe to call knet_han‐
25 dle_remove_datafd even on sockets that have been removed.
26 knet_h - pointer to knet_handle_t
28 *datafd - read/write file descriptor. knet will read data here to send
30 to the other hosts and will write data received from the network. Each
31 data packet can be of max size KNET_MAX_PACKET_SIZE! Applications using
32 knet_send/knet_recv will receive a proper error if the packet size is
33 not within boundaries. Applications using their own functions to write
34 to the datafd should NOT write more than KNET_MAX_PACKET_SIZE.
35 Please refer to handle.c on how to set up a socketpair.
37 datafd can be 0, and knet_handle_add_datafd will create a properly pop‐
39 ulated socket pair the same way as ping_test, or a value higher than 0.
40 A negative number will return an error. On exit knet_handle_free will
41 take care to cleanup the socketpair only if they have been created by
42 knet_handle_add_datafd.
43 It is possible to pass either sockets or normal fds. User provided
45 datafd will be marked as non-blocking and close-on-exec.
46 *channel - This value is analogous to the tag in VLAN tagging. A nega‐
48 tive value will auto-allocate a channel. Setting a value between 0 and
49 31 will try to allocate that specific channel (unless already in use).
50 It is possible to add up to 32 datafds but be aware that each one of
52 them must have a receiving end on the other host.
53 Example: hostA channel 0 will be delivered to datafd on hostB channel 0
55 hostA channel 1 to hostB channel 1.
56 Each channel must have a unique file descriptor.
58 If your application could have 2 channels on one host and one channel
60 on another host, then you can use dst_host_filter to manipulate channel
61 values on TX and RX.
62
64 knet_handle_add_datafd returns
65 0 on success, *datafd will be populated with a socket if the
67 original value was 0 or if a specific fd was set, the value is
68 untouched. *channel will be populated with a channel number if the
69 original value was negative or the value is untouched if a specific
70 channel was requested.
71 -1 on error and errno is set. *datafd and *channel are
73 untouched or empty.
74
76 knet_handle_remove_datafd(3), knet_handle_get_stats(3),
77 knet_host_add(3), knet_handle_pmtud_setfreq(3),
78 knet_handle_pmtud_get(3), knet_handle_crypto_use_config(3),
79 knet_host_get_id_by_host_name(3), knet_host_get_status(3),
80 knet_link_add_acl(3), knet_link_get_pong_count(3),
81 knet_link_get_priority(3), knet_handle_free(3),
82 knet_handle_enable_sock_notify(3), knet_handle_get_datafd(3),
83 knet_recv(3), knet_link_get_ping_timers(3),
84 knet_log_get_subsystem_id(3), knet_host_remove(3),
85 knet_host_enable_status_change_notify(3), knet_strtoaddr(3),
86 knet_link_rm_acl(3), knet_send(3), knet_handle_enable_pmtud_notify(3),
87 knet_handle_get_transport_reconnect_interval(3),
88 knet_link_get_enable(3), knet_link_set_priority(3),
89 knet_log_set_loglevel(3), knet_handle_get_channel(3),
90 knet_link_get_config(3), knet_link_get_link_list(3),
91 knet_get_transport_list(3), knet_get_transport_id_by_name(3),
92 knet_log_get_loglevel_id(3), knet_handle_new_ex(3),
93 knet_host_set_name(3), knet_addrtostr(3), knet_handle_setfwd(3),
94 knet_get_compress_list(3), knet_host_set_policy(3),
95 knet_get_transport_name_by_id(3), knet_handle_enable_filter(3),
96 knet_handle_crypto_rx_clear_traffic(3), knet_handle_compress(3),
97 knet_link_get_status(3), knet_send_sync(3),
98 knet_log_get_loglevel_name(3), knet_handle_enable_access_lists(3),
99 knet_host_get_host_list(3), knet_host_get_policy(3),
100 knet_link_set_enable(3), knet_link_set_pong_count(3),
101 knet_log_get_subsystem_name(3), knet_host_get_name_by_host_id(3),
102 knet_link_clear_config(3), knet_log_get_loglevel(3),
103 knet_handle_new(3), knet_handle_pmtud_getfreq(3),
104 knet_handle_pmtud_set(3), knet_handle_clear_stats(3),
105 knet_link_set_config(3), knet_handle_crypto_set_config(3),
106 knet_handle_crypto(3), knet_get_crypto_list(3),
107 knet_handle_set_transport_reconnect_interval(3),
108 knet_link_clear_acl(3), knet_link_set_ping_timers(3),
109 knet_link_insert_acl(3)
110
112 Copyright (C) 2010-2020 Red Hat, Inc. All rights reserved.
113kronosnet 2020-10-19 KNET_HANDLE_ADD_DATAFD(3)