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rofl0r / microsocks

tiny, portable SOCKS5 server with very moderate resource usage
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Fix the resource exhausting issue. Every process has its maximum open… #48

Closed tjhuang closed 2 years ago

tjhuang commented 2 years ago

Fix the resource exhausting issue. Every process has its maximum opened files limitation (by default 1024). When the microsocks received too many connection requests, then the line "server_waitclient()" would failed and re-try without any delay nor releasing allocated memory. In this fix, whenever failed to service client properly, wait for 1 ms before accepting new connection.

Here are steps to reproduce issue quickly: step 1: On server, execute "microsocks" step 2: On server, limit the maximum FD down to 5 via prlimit --pid <microsocks pid> --nofile=5:5 step 3: On client, create connection to pass through socks server step 4: Monitor the system with "htop" on server, the CPU utilization going high and memory usage is rising.

rofl0r commented 2 years ago

(by default 1024).

default where ?

would failed and re-try without any delay nor releasing allocated memory.

which memory is not released?

tjhuang commented 2 years ago

(by default 1024).

default where ? You can check the current system settings from: $ ulimit -n

And in most system this value should be 1024.

would failed and re-try without any delay nor releasing allocated memory.

which memory is not released? In here: https://github.com/rofl0r/microsocks/blob/master/sockssrv.c#L439 The thread data allocated will not freed, and once "server_waitclient()" return failed, then go through the allocation again and again. In my testing result, this loop will consume more than 100 MB memory within 10 seconds.

rofl0r commented 2 years ago

merged as https://github.com/rofl0r/microsocks/commit/42143b138fc7fd8621dcfc8f2cc69276a1fe9bfe

(modified commit message to adhere to project standard and 80 char line length.)