Hooks in CSP

All hooks in CSP are weak linked functions. Some of them have default implementations, and your program can build and run fine without implementing the hook yourself. Others are relying on the user to provide the functions, and linker will fail because no implementation was found.

Usage of any of the builtin weak functions, will require that you link CSP with -Wl,–link-whole.

TODO: implement a static assert, to catch when the program has been linked without any implementation of csp_print. Because there is no runtime check on this

Debug

void csp_print(const char * fmt, ...);
void csp_output_hook(csp_id_t* idout, csp_packet_t * packet, csp_iface_t * iface, uint16_t via, int from_me);
void csp_input_hook(csp_iface_t * iface, csp_packet_t * packet);

CSP contains a default implementation of csp_print which calls printf. This can be overridden by implementing csp_print in your own application.

input/output_hook are called by the router on all incoming packets, and by the sender on all outgoing packets. The default is to print out a message if the global csp_dbg_print_packet == 1

Crypto

int csp_crypto_decrypt(uint8_t * ciphertext_in, uint8_t ciphertext_len, uint8_t * msg_out);
int csp_crypto_encrypt(uint8_t * msg_begin, uint8_t msg_len, uint8_t * ciphertext_out);

The crypto calls in csp_if_tun does not have a default implementation in CSP and your application will fail to link if you use csp_if_tun without these two functions.

Time

void csp_clock_get_time(csp_timestamp_t * time);
int csp_clock_set_time(const csp_timestamp_t * time);

The get and set time functions rely on arch/<os> and all have default implementations. On FreeRTOS they simply return 0. On posix and zephyr they call clock_gettime(CLOCK_REALTIME, &ts) to get the timestamp from the kernel.

Callback functions in CSP

These callbacks are configured in runtime, by passing a function pointer to a setter function:

typedef int (*csp_sys_reboot_t)(void);
void csp_sys_set_reboot(csp_sys_reboot_t reboot);

typedef int (*csp_sys_shutdown_t)(void);
void csp_sys_set_shutdown(csp_sys_shutdown_t shutdown);