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commit d79814f1b15368ef70f87bb696db6492e8a36c9e Author: David Goulet dgoulet@torproject.org AuthorDate: Mon Jun 27 14:04:06 2022 -0400
hs: PoW extension encoding
Signed-off-by: David Goulet dgoulet@torproject.org --- src/feature/hs/hs_cell.c | 79 +++++++++++++++++++++++++++++++++++++++++++++++- src/feature/hs/hs_cell.h | 2 ++ 2 files changed, 80 insertions(+), 1 deletion(-)
diff --git a/src/feature/hs/hs_cell.c b/src/feature/hs/hs_cell.c index 490f05e54f..32da706a63 100644 --- a/src/feature/hs/hs_cell.c +++ b/src/feature/hs/hs_cell.c @@ -374,6 +374,79 @@ introduce1_encrypt_and_encode(trn_cell_introduce1_t *cell, tor_free(encrypted); }
+/** Build the PoW cell extension and put it in the given extensions object. + * Return 0 on success, -1 on failure. */ +static int +build_introduce_pow_extension(const hs_pow_solution_t *pow_solution, + trn_extension_t *extensions) +{ + ssize_t ret; + size_t pow_ext_encoded_len; + uint8_t *field_array; + trn_extension_field_t *field = NULL; + trn_cell_extension_pow_t *pow_ext = NULL; + + tor_assert(pow_solution); + tor_assert(extensions); + + /* We are creating a cell extension field of type PoW solution. */ + field = trn_extension_field_new(); + trn_extension_field_set_field_type(field, TRUNNEL_CELL_EXTENSION_TYPE_POW); + + /* Build PoW extension field. */ + pow_ext = trn_cell_extension_pow_new(); + + /* Copy PoW solution values into PoW extension cell. */ + + /* Equi-X base scheme */ + trn_cell_extension_pow_set_pow_version(pow_ext, TRUNNEL_POW_EQUIX); + + memcpy(trn_cell_extension_pow_getarray_pow_nonce(pow_ext), + &pow_solution->nonce, TRUNNEL_POW_NONCE_LEN); + + trn_cell_extension_pow_set_pow_effort(pow_ext, pow_solution->effort); + trn_cell_extension_pow_set_pow_seed(pow_ext, pow_solution->seed_head); + + memcpy(trn_cell_extension_pow_getarray_pow_solution(pow_ext), + &pow_solution->equix_solution, TRUNNEL_POW_SOLUTION_LEN); + + /* Set the field with the encoded PoW extension. */ + ret = trn_cell_extension_pow_encoded_len(pow_ext); + if (BUG(ret <= 0)) { + goto err; + } + pow_ext_encoded_len = ret; + + /* Set length field and the field array size length. */ + trn_extension_field_set_field_len(field, pow_ext_encoded_len); + trn_extension_field_setlen_field(field, pow_ext_encoded_len); + /* Encode the PoW extension into the cell extension field. */ + field_array = trn_extension_field_getarray_field(field); + ret = trn_cell_extension_pow_encode(field_array, + trn_extension_field_getlen_field(field), pow_ext); + if (BUG(ret <= 0)) { + goto err; + } + tor_assert(ret == (ssize_t)pow_ext_encoded_len); + + /* Finally, encode field into the cell extension. */ + trn_extension_add_fields(extensions, field); + + /* We've just add an extension field to the cell extensions so increment the + * total number. */ + trn_extension_set_num(extensions, trn_extension_get_num(extensions) + 1); + + /* Cleanup. PoW extension has been encoded at this point. */ + trn_cell_extension_pow_free(pow_ext); + + return 0; + +err: + trn_extension_field_free(field); + trn_cell_extension_pow_free(pow_ext); + return -1; +} + /** Build and set the INTRODUCE congestion control extension in the given * extensions. */ static void @@ -412,10 +485,14 @@ introduce1_set_encrypted(trn_cell_introduce1_t *cell, /* Setup extension(s) if any. */ ext = trn_extension_new(); tor_assert(ext); - /* Build congestion control extension is enabled. */ + /* Build congestion control extension if enabled. */ if (data->cc_enabled) { build_introduce_cc_extension(ext); } + /* Build PoW extension if present. */ + if (data->pow_solution) { + build_introduce_pow_extension(data->pow_solution, ext); + } trn_cell_introduce_encrypted_set_extensions(enc_cell, ext);
/* Set the rendezvous cookie. */ diff --git a/src/feature/hs/hs_cell.h b/src/feature/hs/hs_cell.h index c76a0690a8..538a135491 100644 --- a/src/feature/hs/hs_cell.h +++ b/src/feature/hs/hs_cell.h @@ -42,6 +42,8 @@ typedef struct hs_cell_introduce1_data_t { smartlist_t *link_specifiers; /** Congestion control parameters. */ unsigned int cc_enabled : 1; + /** PoW solution (Can be NULL if disabled). */ + const hs_pow_solution_t *pow_solution; } hs_cell_introduce1_data_t;
/** This data structure contains data that we need to parse an INTRODUCE2 cell