{"abstract":"Ip forwarding expires a packet before hop limit underflows.","category":"Transport flow control","checks":4,"contract":"Bounded offline decision model: ip forwarding expires a packet before hop limit underflows. Inputs are already validated protocol fields; the explicit fixtures define the supported policy, not a complete protocol implementation.","evaluation_group":"xh-ip-forwarding-expires-a-packet-before-hop-limit-underflows","failed_approach":"The attempted repair uses `max(0,ttl-1)` and still violates a separate fixture.","family":"xh-ip-forwarding-expires-a-packet-before-hop-limit-underflows","id":"FA-7326","implementations":{"attempt":{"sha256":"e89d35c4349831cf2e060caec0a80f536fa1f66cd56e1a199c2a549aa42b73b7","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\nimport ipaddress\nimport re\nfrom urllib.parse import urlsplit, urljoin\nN = 1\nobservations = []\ndef solve(ttl):\n    return max(0,ttl-1)\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\n_fixtures = [\"check('fixture 1', solve(1), None)\", \"check('fixture 2', solve(0), None)\", \"check('fixture 3', solve(2), 1)\", \"check('fixture 4', solve(64), 63)\"]\nfor _line in _fixtures[N % len(_fixtures):] + _fixtures[:N % len(_fixtures)]:\n    exec(_line)\nprint(json.dumps({\"observations\": observations, \"passed\": all(x[\"passed\"] for x in observations)}, ensure_ascii=False))\nraise SystemExit(0 if all(x[\"passed\"] for x in observations) else 1)\n"},"broken":{"sha256":"9a65a219d407abbf1fd03efe905bc73830b23241e083151287059463950f5b6a","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\nimport ipaddress\nimport re\nfrom urllib.parse import urlsplit, urljoin\nN = 1\nobservations = []\ndef solve(ttl):\n    return ttl-1\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\n_fixtures = [\"check('fixture 1', solve(1), None)\", \"check('fixture 2', solve(0), None)\", \"check('fixture 3', solve(2), 1)\", \"check('fixture 4', solve(64), 63)\"]\nfor _line in _fixtures[N % len(_fixtures):] + _fixtures[:N % len(_fixtures)]:\n    exec(_line)\nprint(json.dumps({\"observations\": observations, \"passed\": all(x[\"passed\"] for x in observations)}, ensure_ascii=False))\nraise SystemExit(0 if all(x[\"passed\"] for x in observations) else 1)\n"},"fixed":{"sha256":"171f550d2b6b2f3463d4f5b27e04df6976e6725175625f95b8b4166f1c14ff7e","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\nimport ipaddress\nimport re\nfrom urllib.parse import urlsplit, urljoin\nN = 1\nobservations = []\ndef solve(ttl):\n    return ttl-1 if ttl>1 else None\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\n_fixtures = [\"check('fixture 1', solve(1), None)\", \"check('fixture 2', solve(0), None)\", \"check('fixture 3', solve(2), 1)\", \"check('fixture 4', solve(64), 63)\"]\nfor _line in _fixtures[N % len(_fixtures):] + _fixtures[:N % len(_fixtures)]:\n    exec(_line)\nprint(json.dumps({\"observations\": observations, \"passed\": all(x[\"passed\"] for x in observations)}, ensure_ascii=False))\nraise SystemExit(0 if all(x[\"passed\"] for x in observations) else 1)\n"}},"limitations":"Bounded deterministic policy model over validated inputs; not a complete protocol stack or an interoperability claim. The five variants rotate the same explicit fixture set. This reproducer isolates one failure mechanism. Results cover the supplied fixtures. Variants within a family share a test contract and should remain grouped when constructing evaluation splits. Related mechanisms with a shared evaluation_group must also remain together; these controlled models are not independent production incidents.","method":"Deterministic executable model with adversarial boundary fixtures.","provenance":{"created_by":"Failure Map","dependencies":"Python standard library","family":"xh-ip-forwarding-expires-a-packet-before-hop-limit-underflows","generated_at":"2026-09-29T14:38:10.690874+00:00","license":"CC0-1.0","python":"3.12.14","seed":1,"split":"open-access"},"relevance":"This deterministic transport flow control model isolates the ip-forwarding-expires-a-packet-before-hop-limit-underflows policy at a network component boundary.","repair":"Apply the explicit ip-forwarding-expires-a-packet-before-hop-limit-underflows contract, including the tested boundary and negative cases.","root_cause":"The faulty implementation uses `ttl-1` for the ip-forwarding-expires-a-packet-before-hop-limit-underflows decision.","sha256":"170c9de2b7d3fa1a31335484c1335770c669af66192aa8fe7169d1d94b352135","title":"Ip forwarding expires a packet before hop limit underflows · case 01","variant":1,"variant_policy":"Five numbered records share a model and may reuse boundary fixtures.","verification":{"attempt":{"elapsed_ms":46.344,"exit_code":1,"observations":[{"actual":0,"check":"fixture 2","expected":null,"passed":false},{"actual":1,"check":"fixture 3","expected":1,"passed":true},{"actual":63,"check":"fixture 4","expected":63,"passed":true},{"actual":0,"check":"fixture 1","expected":null,"passed":false}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"fixture 2\", \"actual\": 0, \"expected\": null, \"passed\": false}, {\"check\": \"fixture 3\", \"actual\": 1, \"expected\": 1, \"passed\": true}, {\"check\": \"fixture 4\", \"actual\": 63, \"expected\": 63, \"passed\": true}, {\"check\": \"fixture 1\", \"actual\": 0, \"expected\": null, \"passed\": false}], \"passed\": false}\n"},"broken":{"elapsed_ms":46.424,"exit_code":1,"observations":[{"actual":-1,"check":"fixture 2","expected":null,"passed":false},{"actual":1,"check":"fixture 3","expected":1,"passed":true},{"actual":63,"check":"fixture 4","expected":63,"passed":true},{"actual":0,"check":"fixture 1","expected":null,"passed":false}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"fixture 2\", \"actual\": -1, \"expected\": null, \"passed\": false}, {\"check\": \"fixture 3\", \"actual\": 1, \"expected\": 1, \"passed\": true}, {\"check\": \"fixture 4\", \"actual\": 63, \"expected\": 63, \"passed\": true}, {\"check\": \"fixture 1\", \"actual\": 0, \"expected\": null, \"passed\": false}], \"passed\": false}\n"},"fixed":{"elapsed_ms":51.427,"exit_code":0,"observations":[{"actual":null,"check":"fixture 2","expected":null,"passed":true},{"actual":1,"check":"fixture 3","expected":1,"passed":true},{"actual":63,"check":"fixture 4","expected":63,"passed":true},{"actual":null,"check":"fixture 1","expected":null,"passed":true}],"passed":true,"stderr":"","stdout":"{\"observations\": [{\"check\": \"fixture 2\", \"actual\": null, \"expected\": null, \"passed\": true}, {\"check\": \"fixture 3\", \"actual\": 1, \"expected\": 1, \"passed\": true}, {\"check\": \"fixture 4\", \"actual\": 63, \"expected\": 63, \"passed\": true}, {\"check\": \"fixture 1\", \"actual\": null, \"expected\": null, \"passed\": true}], \"passed\": true}\n"}},"verified":true,"visibility":"public"}