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| -rw-r--r-- | v5/apf_interpreter.h | 24 |
1 files changed, 24 insertions, 0 deletions
diff --git a/v5/apf_interpreter.h b/v5/apf_interpreter.h index 376991d..fe3e7af 100644 --- a/v5/apf_interpreter.h +++ b/v5/apf_interpreter.h @@ -129,6 +129,30 @@ int apf_transmit_buffer(void* ctx, uint8_t* ptr, uint32_t len, uint8_t dscp); * * @return non-zero if packet should be passed, * zero if packet should be dropped. + * + * NOTE: How to calculate filter_age_16384ths: + * + * - if you have a u64 clock source counting nanoseconds: + * u64 nanoseconds = current_nanosecond_time_u64() - filter_installation_nanosecond_time_u64; + * u32 filter_age_16384ths = (u32)((nanoseconds << 5) / 1953125); + * + * - if you have a u64 clock source counting microseconds: + * u64 microseconds = current_microsecond_time_u64() - filter_installation_microsecond_time_u64; + * u32 filter_age_16384ths = (u32)((microseconds << 8) / 15625); + * + * - if you have a u64 clock source counting milliseconds: + * u64 milliseconds = current_millisecond_time_u64() - filter_installation_millisecond_time_u64; + * u32 filter_age_16384ths = (u32)((milliseconds << 11) / 125); + * + * - if you have a u32 clock source counting milliseconds and cannot use 64-bit arithmetic: + * u32 milliseconds = current_millisecond_time_u32() - filter_installation_millisecond_time_u32; + * u32 filter_age_16384ths = ((((((milliseconds << 4) / 5) << 2) / 5) << 2) / 5) << 3; + * or the less precise: + * u32 filter_age_16384ths = ((milliseconds << 4) / 125) << 7; + * + * - if you have a u32 clock source counting seconds: + * u32 seconds = current_second_time_u32() - filter_installation_second_time_u32; + * u32 filter_age_16384ths = seconds << 14; */ int apf_run(void* ctx, uint32_t* const program, const uint32_t program_len, const uint32_t ram_len, const uint8_t* const packet, |