commit c7385b5b14b30774c1768798c4495465da4d995d Author: David Goulet <dgoulet@torproject.org> Date: Wed Apr 24 13:38:47 2019 -0400 sendme: Keep cell digest only if a SENDME is next This way, we reduce the load by only hashing when we absolutely must. Part of #26288 Signed-off-by: David Goulet <dgoulet@torproject.org> --- src/core/crypto/relay_crypto.c | 21 +++++++++++++-------- 1 file changed, 13 insertions(+), 8 deletions(-) diff --git a/src/core/crypto/relay_crypto.c b/src/core/crypto/relay_crypto.c index 94e906065..eddc4298e 100644 --- a/src/core/crypto/relay_crypto.c +++ b/src/core/crypto/relay_crypto.c @@ -12,6 +12,7 @@ #include "core/crypto/hs_ntor.h" // for HS_NTOR_KEY_EXPANSION_KDF_OUT_LEN #include "core/or/relay.h" #include "core/crypto/relay_crypto.h" +#include "core/or/sendme.h" #include "core/or/cell_st.h" #include "core/or/or_circuit_st.h" @@ -142,10 +143,11 @@ relay_decrypt_cell(circuit_t *circ, cell_t *cell, if (relay_digest_matches(thishop->crypto.b_digest, cell)) { *recognized = 1; *layer_hint = thishop; - /* Keep current digest of this cell for the possible SENDME. */ - crypto_digest_get_digest(thishop->crypto.b_digest, - (char *) thishop->crypto.sendme_digest, - sizeof(thishop->crypto.sendme_digest)); + /* This cell is for us. Keep a record of this cell because we will + * use it in the next SENDME cell. */ + if (sendme_circuit_is_next_cell(thishop->deliver_window)) { + sendme_circuit_note_inbound_cell(thishop); + } return 0; } } @@ -216,10 +218,13 @@ relay_encrypt_cell_inbound(cell_t *cell, or_circuit_t *or_circ) { relay_set_digest(or_circ->crypto.b_digest, cell); - /* Keep a record of this cell, we might use it for validating the SENDME. */ - crypto_digest_get_digest(or_circ->crypto.b_digest, - (char *) or_circ->crypto.sendme_digest, - sizeof(or_circ->crypto.sendme_digest)); + + /* We are about to send this cell outbound on the circuit. Keep a record of + * this cell if we are expecting that the next cell is a SENDME. */ + if (sendme_circuit_is_next_cell(TO_CIRCUIT(or_circ)->package_window)) { + sendme_circuit_note_outbound_cell(or_circ); + } + /* encrypt one layer */ relay_crypt_one_payload(or_circ->crypto.b_crypto, cell->payload); }