Differential D23342 Diff 64295 plugins/process/network/README.md

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		1		Per-process Network Usage Plugin
		2		================================
		3
		4		This plugin tries to track per-process network usage and feeds that back to
		5		ksysguard. Unfortunately, at the moment there is no unpriviledged API available
		6		for this information, so this plugin uses a small helper application to work
		7		around that. The helper uses libpcap to do packet capture. To do the packet
		8		capture it needs `cap_net_raw`, but nothing else.
		9
		10		The helper only tracks TCP and UDP traffic, on IPv4 or IPv6 networks. Only the
		11		beginning of each packet is captured, so we only get the packet headers. These
		12		are processed to extract the source and destination IP address and port, which
		13		are matched with sockets and processes.
		14
		15		The matching uses information parsed from `/proc/net/tcp{,6}` and
		16		`/proc/net/udp{,6}` for the sockets, which are mapped to processes by listing
		17		fds from `/proc/${pid}/fd/` and reading their symlink targets. Entries matching
		18		`socket:[${port}]` are used to track socket to process mapping.
		19
		20		Once mapped, we store how much data was received for each process by
		21		accumulating the packet sizes for each socket. Every second this information is
		22		printed to the helper's stdout using the format
		23		`00:00:00\|PID\|0000\|IN\|000\|OUT\|000` or just `00:00:00` if there was no data that
		24		second. The helper's stdout is read and parsed by the network plugin and fed
		25		into ksysguard.