[GIT PULL] Fix various socks5 bugs

[ammarfaizi2]

After stress-testing the SOCKS5 proxy server, I found various memory
corruption bugs. Here is the stress-test program:

https://gist.github.com/ammarfaizi2/53324bb7dd8ca7cb73a92b80b62f8f3b

Only the first patch is not related to memory corruption bugs.

1) Fix the wrong batch condition decision.

If there are 1 entries and 5 workers, and nr_sleeping is 5. It will
always batch because nr_entries + 16 is always greater than 5. That's
just wrong.

2) Handle GWP_SOCKS5_ST_CMD_CONNECT in gwp_socks5_conn_handle_data().

The gwp_socks5_conn_handle_data() does not properly handle socks5
data if the CONNECT command comes together with the proxied data.

3) Fix missing buf advance and target.len increment.

gwp_socks5_conn_handle_data() may return -EAGAIN and have in_len
or out_len greater than zero. Make sure to account those values.

4) Fix an invalid handle_socks5_data() call.

The call to handle_socks5_data() must only be done when the
connection is in CONN_STATE_SOCKS5_DATA state.

The following changes since commit 19a2f3db2bdba27a98d77b2f1093ce637155e443:

  Merge branch 'dns' (DNS library integration) (2025-07-17 19:21:22 +0700)

are available in the Git repository at:

  https://github.com/ammarfaizi2/gwproxy.git bug-fix

for you to fetch changes up to 33e63762f946a6180696d4aef7d62362840da486:

  gwproxy: Fix an invalid `handle_socks5_data()` call (2025-07-19 12:32:37 +0700)

----------------------------------------------------------------
Ammar Faizi (4):
      gwproxy/dns: Fix the wrong batch condition decision
      gwproxy/socks5: Handle `GWP_SOCKS5_ST_CMD_CONNECT` in `gwp_socks5_conn_handle_data()`
      gwproxy: Fix missing buf advance and `target.len` increment
      gwproxy: Fix an invalid `handle_socks5_data()` call

 src/gwproxy/dns.c     |  2 +-
 src/gwproxy/gwproxy.c | 18 ++++++++++--------
 src/gwproxy/socks5.c  |  4 ++++
 3 files changed, 15 insertions(+), 9 deletions(-)