1FIDO_DEV_SET_IO_FUNCT... BSD Library Functions Manual FIDO_DEV_SET_IO_FUNCT...
2
4 fido_dev_set_io_functions, fido_dev_set_sigmask, fido_dev_set_timeout,
5 fido_dev_set_transport_functions, fido_dev_io_handle — FIDO2 device I/O
6 interface
7
9 #include <fido.h>
10 typedef void *fido_dev_io_open_t(const char *);
12 typedef void fido_dev_io_close_t(void *);
13 typedef int fido_dev_io_read_t(void *, unsigned char *, size_t, int);
14 typedef int fido_dev_io_write_t(void *, const unsigned char *, size_t);
15 typedef struct fido_dev_io {
17 fido_dev_io_open_t *open;
18 fido_dev_io_close_t *close;
19 fido_dev_io_read_t *read;
20 fido_dev_io_write_t *write;
21 } fido_dev_io_t;
22 #ifdef _WIN32
24 typedef int fido_sigset_t;
25 #else
26 typedef sigset_t fido_sigset_t;
27 #endif
28 typedef int fido_dev_rx_t(struct fido_dev *,
30 uint8_t, unsigned char *, size_t, int);
31 typedef int fido_dev_tx_t(struct fido_dev *,
32 uint8_t, const unsigned char *, size_t);
33 typedef struct fido_dev_transport {
35 fido_dev_rx_t *rx;
36 fido_dev_tx_t *tx;
37 } fido_dev_transport_t;
38 int
40 fido_dev_set_io_functions(fido_dev_t *dev, const fido_dev_io_t *io);
41 int
43 fido_dev_set_sigmask(fido_dev_t *dev, const fido_sigset_t *sigmask);
44 int
46 fido_dev_set_timeout(fido_dev_t *dev, int ms);
47 int
49 fido_dev_set_transport_functions(fido_dev_t *dev,
50 const fido_dev_transport_t *t);
51 void *
53 fido_dev_io_handle(const fido_dev_t *dev);
54
56 The fido_dev_set_io_functions() function sets the I/O handlers used by
57 libfido2 to talk to dev. By default, these handlers are set to the oper‐
58 ating system's native HID or NFC interfaces. They are defined as fol‐
59 lows:
60 fido_dev_open_t
62 Receives a const char * holding a path and opens the correspond‐
63 ing device, returning a non-NULL opaque pointer on success and
64 NULL on error.
65 fido_dev_close_t
67 Receives the opaque pointer returned by fido_dev_open_t and
68 closes the device.
69 fido_dev_read_t
71 Reads a single transmission unit (HID report, APDU) from a de‐
72 vice. The first parameter is the opaque pointer returned by
73 fido_dev_open_t. The second parameter is the read buffer, and
74 the third parameter is the read buffer size. The fourth parame‐
75 ter is the number of milliseconds the caller is willing to sleep,
76 should the call need to block. If this value holds -1,
77 fido_dev_read_t may block indefinitely. On success, the number
78 of bytes read is returned. On error, -1 is returned.
79 fido_dev_write_t
81 Writes a single transmission unit (HID report, APDU) to dev. The
82 first parameter is the opaque pointer returned by
83 fido_dev_open_t. The second parameter is the write buffer, and
84 the third parameter is the number of bytes to be written. A
85 fido_dev_write_t may block. On success, the number of bytes
86 written is returned. On error, -1 is returned.
87 When calling fido_dev_set_io_functions(), the open, close, read, and
89 write fields of io may not be NULL.
90 No references to io are held by fido_dev_set_io_functions().
92 The fido_dev_set_sigmask() function may be used to specify a non-NULL
94 signal mask sigmask to be used while libfido2's default I/O handlers wait
95 on dev. On UNIX-like operating systems, fido_sigset_t is defined as
96 sigset_t. On Windows, fido_sigset_t is defined as int and
97 fido_dev_set_sigmask() is a no-op.
98 No references to sigmask are held by fido_dev_set_sigmask().
100 The fido_dev_set_timeout() function informs libfido2 not to block for
102 more than ms milliseconds while communicating with dev. If a timeout oc‐
103 curs, the corresponding fido_dev_* function will fail with FIDO_ERR_RX.
104 If ms is -1, then libfido2 may block indefinitely. This is the default
105 behaviour. When using the Windows Hello backend, ms is used as a guid‐
106 ance and may be overwritten by the platform.
107 The fido_dev_set_transport_functions() function sets the transport func‐
109 tions used by libfido2 to talk to dev. While the I/O handlers are re‐
110 sponsible for sending and receiving transmission units of initialization
111 and continuation packets already formatted by libfido2, the transport
112 handlers are responsible for sending and receiving the CTAPHID commands
113 and data directly, as defined in the FIDO Client to Authenticator Proto‐
114 col (CTAP) standard. They are defined as follows:
115 fido_dev_tx_t
117 Receives a device, a CTAPHID command to transmit, a data buffer
118 to transmit, and the length of the data buffer. On success, 0 is
119 returned. On error, -1 is returned.
120 fido_dev_rx_t
122 Receives a device, a CTAPHID command whose response the caller
123 expects to receive, a data buffer to receive into, the size of
124 the data buffer determining the maximum length of a response, and
125 the maximum number of milliseconds to wait for a response. On
126 success, the number of bytes read into the data buffer is re‐
127 turned. On error, -1 is returned.
128 When transport functions are specified, libfido2 will use them instead of
130 the read and write functions of the I/O handlers. However, the I/O han‐
131 dlers must still be specified to open and close the device.
132 The fido_dev_io_handle() function returns the opaque pointer returned by
134 the open function of the I/O handlers. This is useful mainly for the
135 transport functions, which unlike the I/O handlers are passed the
136 fido_dev_t pointer instead of the opaque I/O handle.
137
139 On success, fido_dev_set_io_functions(),
140 fido_dev_set_transport_functions(), fido_dev_set_sigmask(), and
141 fido_dev_set_timeout() return FIDO_OK. On error, a different error code
142 defined in <fido/err.h> is returned.
143
145 fido_dev_info_manifest(3), fido_dev_open(3)
146 Client to Authenticator Protocol (CTAP),
148 https://fidoalliance.org/specs/fido-v2.1-ps-20210615/fido-client-to-
149 authenticator-protocol-v2.1-ps-20210615.html, FIDO Alliance, 2021-06-15,
150 Proposed Standard, Version 2.1.
151BSD May 25, 2018 BSD