aws / s2n-tls - Conditional Complexity

Intro

Conditional complexity (also called cyclomatic complexity) is a term used to measure the complexity of software. The term refers to the number of possible paths through a program function. A higher value ofter means higher maintenance and testing costs (infosecinstitute.com).
Conditional complexity is calculated by counting all conditions in the program that can affect the execution path (e.g. if statement, loops, switches, and/or operators, try and catch blocks...).
Conditional complexity is measured at the unit level (methods, functions...).
Units are classified in four categories based on the measured McCabe index: 1-5 (simple units), 6-10 (medium complex units), 11-25 (complex units), 26+ (very complex units).

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Conditional Complexity Overall

There are 2,001 units with 27,282 lines of code in units (57.7% of code).

0 very complex units (0 lines of code)
1 complex units (170 lines of code)
21 medium complex units (1,264 lines of code)
94 simple units (3,076 lines of code)
1,885 very simple units (22,772 lines of code)

Legend:

51+

26-50

11-25

6-10

1-5

Alternative Visuals

3D view of all units

Conditional Complexity per Extension

51+

26-50

11-25

6-10

1-5

Conditional Complexity per Logical Component

primary logical decomposition

51+

26-50

11-25

6-10

1-5

Most Complex Units

Top 50 most complex units

Unit	# lines	McCabe index	# params
int s2n_record_writev() in tls/s2n_record_write.c	170	36	6
int s2n_conn_set_handshake_type() in tls/s2n_handshake_io.c	60	22	1
static int s2n_handshake_read_io() in tls/s2n_handshake_io.c	85	22	1
ssize_t s2n_recv_impl() in tls/s2n_recv.c	68	22	4
static int s2n_set_cipher_as_server() in tls/s2n_cipher_suites.c	81	21	4
S2N_RESULT s2n_inet_ntop() in utils/s2n_rfc5952.c	68	17	3
int s2n_negotiate_impl() in tls/s2n_handshake_io.c	63	17	2
int s2n_connection_set_config() in tls/s2n_connection.c	53	16	2
ssize_t s2n_sendv_with_offset_impl() in tls/s2n_send.c	66	16	5
static int s2n_client_key_share_recv_pq_hybrid() in tls/extensions/s2n_client_key_share.c	63	15	3
static int s2n_server_hello_parse() in tls/s2n_server_hello.c	75	13	1
static S2N_RESULT s2n_x509_validator_verify_cert_chain() in tls/s2n_x509_validator.c	54	13	2
bool s2n_connection_check_io_status() in tls/s2n_connection.c	30	13	2
int s2n_process_client_hello() in tls/s2n_client_hello.c	57	12	1
fn raw_may_allocate_memory() in bindings/rust/extended/s2n-tls/src/fingerprint.rs	53	11	0
static int s2n_rand_get_entropy_from_rdrand() in utils/s2n_random.c	65	11	2
static int s2n_advance_message() in tls/s2n_handshake_io.c	26	11	1
S2N_RESULT s2n_x509_validator_validate_cert_stapled_ocsp_response() in tls/s2n_x509_validator.c	75	11	4
S2N_RESULT s2n_signature_algorithm_select() in tls/s2n_signature_algorithms.c	48	11	1
int s2n_read_full_record() in tls/s2n_recv.c	47	11	3
static S2N_RESULT s2n_client_hello_verify_for_retry() in tls/s2n_client_hello.c	67	11	4
int s2n_client_hello_send() in tls/s2n_client_hello.c	60	11	1
bool s2n_hash_is_available() in crypto/s2n_hash.c	17	10	1
int s2n_hmac_hash_alg() in crypto/s2n_hmac.c	18	10	2
int s2n_hmac_xor_pad_size() in crypto/s2n_hmac.c	18	10	2
int s2n_hmac_hash_block_size() in crypto/s2n_hmac.c	18	10	2
static S2N_RESULT s2n_conn_set_tls13_handshake_type() in tls/s2n_handshake_io.c	25	10	1
S2N_RESULT s2n_send_early_data_impl() in tls/s2n_early_data_io.c	47	10	5
S2N_RESULT s2n_tls13_server_nst_send() in tls/s2n_server_new_session_ticket.c	34	10	2
int s2n_security_policies_init() in tls/s2n_security_policies.c	44	10	0
static uint8_t s2n_default_verify_host() in tls/s2n_connection.c	20	10	3
S2N_RESULT s2n_config_validate_loaded_certificates() in tls/s2n_config.c	38	10	2
def scram_decrypt() in scram/aes_scram.py	42	9	6
int s2n_hash_digest_size() in crypto/s2n_hash.c	17	9	2
int s2n_hash_hmac_alg() in crypto/s2n_hmac.c	17	9	2
S2N_RESULT s2n_hmac_md_from_alg() in crypto/s2n_hmac.c	29	9	2
int s2n_cert_chain_and_key_load_cns() in crypto/s2n_certificate.c	40	9	2
int s2n_cert_chain_and_key_free() in crypto/s2n_certificate.c	45	9	1
int s2n_conn_update_required_handshake_hashes() in tls/s2n_handshake.c	31	9	1
int s2n_conn_update_handshake_hashes() in tls/s2n_handshake_transcript.c	32	9	2
static S2N_RESULT s2n_check_kem() in tls/s2n_kex.c	38	9	3
int s2n_error_get_alert() in tls/s2n_alerts.c	22	9	2
S2N_RESULT s2n_post_handshake_message_recv() in tls/s2n_post_handshake.c	52	9	1
int s2n_record_parse() in tls/s2n_record_read.c	50	9	1
int s2n_cipher_suites_init() in tls/s2n_cipher_suites.c	41	9	1
bool s2n_pq_kem_is_extension_required() in tls/s2n_security_policies.c	24	9	1
S2N_CLEANUP_RESULT s2n_connection_apply_error_blinding() in tls/s2n_connection.c	31	9	1
def scram_encrypt() in scram/aes_scram.py	48	8	5
S2N_RESULT s2n_security_rule_validate_policy() in tls/s2n_security_rules.c	82	8	3
static int s2n_handshake_get_hash_state_ptr() in tls/s2n_handshake.c	32	8	3