server: disconnect lightway in case of TCP shutdown or other fatal failures

[kp-mariappan-ramasamy]

Description

Disconnect lightway in case of TCP shutdown or other fatal failures.

Note that it is possible, disconnect has been called in conn.handle_outside_data_error already in case of fatal error case. It is still fine to call it again, since disconnect call is idempotent and no-op if it is already disconnected

But we need this disconnect in case of TCP connection shutdown. Otherwise Server::Connection will be leaking.

Motivation and Context

TCP connections are not getting closed in some servers

How Has This Been Tested?

Verified in running prod server

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)

Checklist:

• My change requires a change to the documentation.
• I have updated the documentation accordingly.
• The correct base branch is being used, if not main

[github-actions]

Code coverage summary for db3d430:

Filename                                                     Regions    Missed Regions     Cover   Functions  Missed Functions  Executed       Lines      Missed Lines     Cover    Branches   Missed Branches     Cover
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
lightway-app-utils/src/args/cipher.rs                              4                 4     0.00%           1                 1     0.00%           5                 5     0.00%           0                 0         -
lightway-app-utils/src/args/connection_type.rs                     4                 4     0.00%           1                 1     0.00%           5                 5     0.00%           0                 0         -
lightway-app-utils/src/args/duration.rs                            7                 7     0.00%           5                 5     0.00%          13                13     0.00%           0                 0         -
lightway-app-utils/src/args/ip_map.rs                             11                11     0.00%           3                 3     0.00%          15                15     0.00%           0                 0         -
lightway-app-utils/src/args/logging.rs                            14                14     0.00%           2                 2     0.00%          16                16     0.00%           0                 0         -
lightway-app-utils/src/connection_ticker.rs                       71                11    84.51%          28                 4    85.71%         279                11    96.06%           0                 0         -
lightway-app-utils/src/dplpmtud_timer.rs                          63                 7    88.89%          22                 4    81.82%         282                11    96.10%           0                 0         -
lightway-app-utils/src/event_stream.rs                             5                 0   100.00%           3                 0   100.00%          13                 0   100.00%           0                 0         -
lightway-app-utils/src/iouring.rs                                157               142     9.55%          23                17    26.09%         304               281     7.57%           0                 0         -
lightway-app-utils/src/metrics.rs                                  2                 2     0.00%           2                 2     0.00%           4                 4     0.00%           0                 0         -
lightway-app-utils/src/sockopt/ip_mtu_discover.rs                 23                23     0.00%           4                 4     0.00%          93                93     0.00%           0                 0         -
lightway-app-utils/src/sockopt/ip_pktinfo.rs                       4                 4     0.00%           1                 1     0.00%          16                16     0.00%           0                 0         -
lightway-app-utils/src/tun.rs                                     76                76     0.00%          22                22     0.00%          94                94     0.00%           0                 0         -
lightway-app-utils/src/utils.rs                                   13                13     0.00%           1                 1     0.00%          11                11     0.00%           0                 0         -
lightway-client/src/args.rs                                       35                35     0.00%          31                31     0.00%          38                38     0.00%           0                 0         -
lightway-client/src/io/inside/tun.rs                              39                39     0.00%           7                 7     0.00%          48                48     0.00%           0                 0         -
lightway-client/src/io/outside/tcp.rs                             48                48     0.00%          10                10     0.00%          45                45     0.00%           0                 0         -
lightway-client/src/io/outside/udp.rs                             62                62     0.00%          12                12     0.00%          62                62     0.00%           0                 0         -
lightway-client/src/keepalive.rs                                 245                33    86.53%          56                 8    85.71%         372                26    93.01%           0                 0         -
lightway-client/src/lib.rs                                       257               257     0.00%          27                27     0.00%         383               383     0.00%           0                 0         -
lightway-client/src/main.rs                                       48                48     0.00%           7                 7     0.00%         169               169     0.00%           0                 0         -
lightway-core/src/borrowed_bytesmut.rs                            86                 1    98.84%          24                 0   100.00%         196                 1    99.49%           0                 0         -
lightway-core/src/builder_predicates.rs                           20                10    50.00%           4                 2    50.00%          28                14    50.00%           0                 0         -
lightway-core/src/cipher.rs                                        8                 0   100.00%           3                 0   100.00%          13                 0   100.00%           0                 0         -
lightway-core/src/connection.rs                                  668               401    39.97%          58                27    53.45%         875               463    47.09%           0                 0         -
lightway-core/src/connection/builders.rs                          67                25    62.69%          22                11    50.00%         260                56    78.46%           0                 0         -
lightway-core/src/connection/dplpmtud.rs                         761                90    88.17%          66                 1    98.48%         947                11    98.84%           0                 0         -
lightway-core/src/connection/fragment_map.rs                     132                11    91.67%          27                 0   100.00%         290                 7    97.59%           0                 0         -
lightway-core/src/connection/io_adapter.rs                       137                17    87.59%          36                 5    86.11%         313                23    92.65%           0                 0         -
lightway-core/src/connection/key_update.rs                        23                 7    69.57%           5                 0   100.00%          38                19    50.00%           0                 0         -
lightway-core/src/context.rs                                      91                27    70.33%          26                 9    65.38%         213                52    75.59%           0                 0         -
lightway-core/src/context/ip_pool.rs                               7                 3    57.14%           1                 0   100.00%           6                 0   100.00%           0                 0         -
lightway-core/src/context/server_auth.rs                          14                11    21.43%           4                 3    25.00%          24                20    16.67%           0                 0         -
lightway-core/src/io.rs                                            3                 3     0.00%           3                 3     0.00%          10                10     0.00%           0                 0         -
lightway-core/src/lib.rs                                           9                 6    33.33%           4                 1    75.00%          18                 9    50.00%           0                 0         -
lightway-core/src/metrics.rs                                      17                17     0.00%          15                15     0.00%          33                33     0.00%           0                 0         -
lightway-core/src/packet.rs                                       27                 7    74.07%           4                 1    75.00%          30                 6    80.00%           0                 0         -
lightway-core/src/plugin.rs                                       66                 8    87.88%          23                 5    78.26%         160                 9    94.38%           0                 0         -
lightway-core/src/utils.rs                                       101                21    79.21%          22                 2    90.91%         184                17    90.76%           0                 0         -
lightway-core/src/version.rs                                      37                 0   100.00%          19                 0   100.00%          89                 0   100.00%           0                 0         -
lightway-core/src/wire.rs                                        156                27    82.69%          32                 0   100.00%         267                 6    97.75%           0                 0         -
lightway-core/src/wire/auth_failure.rs                             9                 1    88.89%           3                 0   100.00%          19                 0   100.00%           0                 0         -
lightway-core/src/wire/auth_request.rs                           147                12    91.84%          34                 0   100.00%         287                 0   100.00%           0                 0         -
lightway-core/src/wire/auth_success_with_config_ipv4.rs           69                 4    94.20%          13                 0   100.00%         145                 0   100.00%           0                 0         -
lightway-core/src/wire/data.rs                                    20                 1    95.00%           7                 0   100.00%          43                 0   100.00%           0                 0         -
lightway-core/src/wire/data_frag.rs                               41                 1    97.56%          17                 0   100.00%          92                 0   100.00%           0                 0         -
lightway-core/src/wire/encoding_request.rs                        22                 2    90.91%           6                 0   100.00%          44                 1    97.73%           0                 0         -
lightway-core/src/wire/encoding_response.rs                       22                 2    90.91%           6                 0   100.00%          44                 1    97.73%           0                 0         -
lightway-core/src/wire/ping.rs                                    22                 3    86.36%           7                 0   100.00%          68                 0   100.00%           0                 0         -
lightway-core/src/wire/pong.rs                                    15                 2    86.67%           5                 0   100.00%          34                 0   100.00%           0                 0         -
lightway-core/src/wire/server_config.rs                           20                 2    90.00%           5                 0   100.00%          44                 0   100.00%           0                 0         -
lightway-server/src/args.rs                                       30                30     0.00%          30                30     0.00%          30                30     0.00%           0                 0         -
lightway-server/src/auth.rs                                      104                36    65.38%          19                 5    73.68%         148                28    81.08%           0                 0         -
lightway-server/src/connection.rs                                 57                57     0.00%          25                25     0.00%         124               124     0.00%           0                 0         -
lightway-server/src/connection_manager.rs                         87                87     0.00%          25                25     0.00%         207               207     0.00%           0                 0         -
lightway-server/src/connection_manager/connection_map.rs          87                 8    90.80%          26                 2    92.31%         273                 8    97.07%           0                 0         -
lightway-server/src/io/inside/tun.rs                              25                25     0.00%           8                 8     0.00%          34                34     0.00%           0                 0         -
lightway-server/src/io/outside/tcp.rs                             80                80     0.00%           8                 8     0.00%          99                99     0.00%           0                 0         -
lightway-server/src/io/outside/udp.rs                            144               144     0.00%          18                18     0.00%         263               263     0.00%           0                 0         -
lightway-server/src/io/outside/udp/cmsg.rs                        47                16    65.96%          14                 5    64.29%         237                56    76.37%           0                 0         -
lightway-server/src/ip_manager.rs                                 82                25    69.51%          19                 4    78.95%         254                28    88.98%           0                 0         -
lightway-server/src/ip_manager/ip_pool.rs                        101                 1    99.01%          32                 0   100.00%         305                 0   100.00%           0                 0         -
lightway-server/src/lib.rs                                       122               122     0.00%          14                14     0.00%         198               198     0.00%           0                 0         -
lightway-server/src/main.rs                                       81                81     0.00%          10                10     0.00%         217               217     0.00%           0                 0         -
lightway-server/src/metrics.rs                                    93                91     2.15%          82                80     2.44%         220               216     1.82%           0                 0         -
lightway-server/src/statistics.rs                                 53                23    56.60%           8                 4    50.00%         103                42    59.22%           0                 0         -
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
TOTAL                                                           5198              2388    54.06%        1107               492    55.56%        9793              3654    62.69%           0                 0         -

✅ Region coverage 54% passes
✅ Line coverage 62% passes