(WIP) Rework of DTLS code, add DTLS PKI/RPK

[pulsastrix]

This PR refactors the cryptography related code to improve usage ergonomics and to add DTLS support using PKI/RPK.

Still a WIP, not ready for reviews yet.

Closes #30, Closes #4.

[github-actions]

Workflow Status Report

Generated for commit 7c58a25 on Wed Sep 11 18:18:27 UTC 2024.

Linting Report

Clippy check result: failure

Refer to the "Files Changed" tab for identified issues.

Code Coverage Report

Filename                             Stmts    Miss  Cover    Missing
---------------------------------  -------  ------  -------  -----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
libcoap/src/crypto/psk/client.rs        62      43  30.65%   44-47, 55, 70-131, 171-177, 203, 210, 229-248
libcoap/src/crypto/psk/key.rs           44      19  56.82%   29-34, 133-174
libcoap/src/crypto/psk/server.rs        81      66  18.52%   44-53, 61, 64-76, 101, 108, 115, 142-185, 212-304
libcoap/src/message/mod.rs             245     124  49.39%   107-110, 112-133, 141-147, 149-170, 174, 176, 210, 212, 215-224, 227-245, 247-251, 267-276, 297-303, 400, 443, 449, 480, 488, 490-492, 499-500, 508, 513-526, 531, 551-552, 563-564
libcoap/src/message/request.rs         220     150  31.82%   52, 69-202, 229-257, 265-375, 381, 384-386, 390, 397-401, 412, 416, 431-432, 437, 440-441, 445-446, 450, 453, 456, 459, 462, 473-477
libcoap/src/message/response.rs        143     111  22.38%   33-156, 162, 165, 168, 171, 174, 192-322, 326-330, 356-357
libcoap-sys/src/lib.rs                  97      35  63.92%   115-151, 183, 188, 193, 198, 208, 213, 223, 228, 233, 238, 243, 248, 253, 258, 263, 268, 278, 320-337, 459-460
libcoap/src/session/client.rs           76      16  78.95%   57, 151, 157, 178, 184, 212-213, 219-229, 276-281
libcoap/src/session/mod.rs             154      91  40.91%   63-69, 98-99, 113-227, 238-281, 291-293, 303-313, 349, 364, 379-398, 421, 429, 453, 457, 478-482, 560, 566
libcoap/src/session/server.rs           48      12  75.00%   71-73, 140-141, 149-150, 181-186
libcoap/src/context.rs                 171      90  47.37%   46, 85, 90-95, 101-102, 107, 112, 114, 148-191, 200-208, 222, 227, 244, 249, 268, 304, 334, 339, 355, 363-524
libcoap/src/error.rs                     4       4  0.00%    87-166
libcoap/src/event.rs                     9       0  100.00%
libcoap/src/mem.rs                     118      48  59.32%   145-159, 193-194, 207-208, 268-294, 316-320, 350-351, 364-366, 378-389, 449-485, 504, 523-524, 527-528
libcoap/src/prng.rs                     18      14  22.22%   67-179
libcoap/src/protocol.rs                150     110  26.67%   145-146, 152-157, 159-174, 176-177, 184-189, 191-206, 208-209, 266-267, 289, 303-304, 347-352, 361-380, 437-482, 515, 517
libcoap/src/resource.rs                139      69  50.36%   96-98, 173-208, 216-221, 248, 251, 254, 257, 268-289, 302-304, 329-333, 340-341, 350-352, 358-360, 366-374, 496, 498-509
libcoap/src/transport.rs                10       3  70.00%   28-33, 54
libcoap/src/types.rs                   233     163  30.04%   76-121, 128-157, 200-275, 285, 411-451, 504-578, 636, 662-712, 766, 781, 811-831, 853-874, 887-971
libcoap/src/crypto/pki_rpk/key.rs       50      30  40.00%   109-187, 195-203, 205-215
libcoap/src/crypto/pki_rpk/mod.rs      120      88  26.67%   113-139, 149-191, 201, 204-238, 251, 258, 265, 291, 293, 297, 324-406
libcoap/src/crypto/pki_rpk/pki.rs       30      10  66.67%   33-42, 102-109
libcoap/src/crypto/pki_rpk/rpk.rs       17       6  64.71%   57-58, 103-106
libcoap/tests/common/dtls.rs            19       2  89.47%   33, 39
libcoap/tests/common/mod.rs             47       5  89.36%   71, 101, 103-104, 107
TOTAL                                 2305    1309  43.21%

Diff against main

Filename                             Stmts    Miss  Cover
---------------------------------  -------  ------  -------
libcoap/src/crypto/psk/client.rs       +62     +43  +30.65%
libcoap/src/crypto/psk/key.rs          +44     +19  +56.82%
libcoap/src/crypto/psk/server.rs       +81     +66  +18.52%
libcoap-sys/src/lib.rs                  +6      +3  -0.92%
libcoap/src/session/client.rs          -59     -46  +24.87%
libcoap/src/session/mod.rs               0      +5  -3.25%
libcoap/src/context.rs                 -46     -24  -0.10%
libcoap/src/types.rs                    -2      +3  -1.87%
libcoap/src/crypto/pki_rpk/key.rs      +50     +30  +40.00%
libcoap/src/crypto/pki_rpk/mod.rs     +120     +88  +26.67%
libcoap/src/crypto/pki_rpk/pki.rs      +30     +10  +66.67%
libcoap/src/crypto/pki_rpk/rpk.rs      +17      +6  +64.71%
libcoap/tests/common/dtls.rs           +19      +2  +89.47%
libcoap/tests/common/mod.rs             +4       0  +0.99%
TOTAL                                 +326    +205  -2.04%

Results for commit: 29cf312

Coverage target is 80%