Net stat feature

[navidpadid]

This pull request adds a new per-process network statistics section to the output, providing a brief summary of socket usage and TCP network counters, and updates documentation and tests accordingly. The main changes include collecting and displaying aggregated network stats, tracking per-interface socket usage, and ensuring robust test coverage for the new functionality.

New network statistics feature:

• Adds a [network] section to the process output, showing total sockets, breakdown by protocol (TCP/UDP/UNIX), TCP packet and byte counters, retransmits, drops, and per-interface socket counts. (src/elf_det.c [1] [2]
• Introduces the struct netdev_count and related helpers for tracking and displaying socket counts per network device/interface. (src/elf_det.h [1] [2]

Documentation updates:

• Documents the new network stats section, its fields, and limitations in both the user-facing (README.md) and technical documentation (docs/TECHNICAL.md). (README.md [1] [2]; docs/TECHNICAL.md [3] [4]
• Adds guidance and expectations for testing the network stats output in the testing documentation. (docs/TESTING.md [1] [2]

Testing improvements:

• Expands end-to-end tests to check for the presence and correctness of the [network] section and its key fields in the output for various processes. (e2e/qemu-test.sh [1] [2] [3]
• Adds unit tests for the add_netdev_count helper to ensure correct aggregation and boundary handling. (src/elf_det_tests.c src/elf_det_tests.cR500-R540)

Miscellaneous:

• Updates includes and definitions to support the new functionality (e.g., network device structures, interface name sizing). (src/elf_det.c [1] src/elf_det.h [2]

These changes collectively provide users with a concise overview of a process's network activity and resource usage, and improve observability and testability for the new feature.