SOX - socket options extractor/setter.

Sox enables you to retrieve or modify any TCP socket option for any process. This can be particularly useful for debugging purposes. Additionally, Sox can serve as a quick fix by allowing you to change socket options for any application without requiring a restart or causing downtime.

Requirements:

• Linux kernel 5.6+
• CAP_SYS_PTRACE
  capability

Instalation:

go install github.com/valexz/sox@latest

Usage example

Get pid and fd of socket via ss:

❯ sudo ss -ntpa
State       Recv-Q       Send-Q     Local Address:Port           Peer Address:Port        Process                                               
LISTEN      0            128        0.0.0.0:22                   0.0.0.0:*                users:(("sshd",pid=1062,fd=3))                       

List all socket options for sshd process with PID=1062 and tcp socket with FD=3

❯ sudo ./sox list 1062 3
OPTION NAME             VALUE           DESCRIPTION                            
SO_KEEPALIVE            1               Enable or disable TCP keepalive        
TCP_KEEPIDLE            7200            Start keepalives after this period     
TCP_KEEPINTVL           75              Interval between keepalives            
TCP_KEEPCNT             9               Number of keepalives before death      
TCP_NODELAY             0               Disable Nagle's algorithm              
TCP_MAXSEG              536             Maximum segment size                   
TCP_CORK                0               Control sending of partial frames      
TCP_SYNCNT              6               Number of SYN retransmits              
TCP_LINGER2             60              Lifetime of orphaned FIN-WAIT-2 state  
TCP_DEFER_ACCEPT        0               Wake up listener only when data arrives
TCP_WINDOW_CLAMP        0               Set maximum window size                
TCP_INFO                10              Information about this socket          
TCP_QUICKACK            1               Enable quick ACK                       
TCP_CONGESTION          1768060259      Get/Set congestion control algorithm   
TCP_REPAIR              0               TCP repair mode                        
TCP_FASTOPEN            0               Enable TCP Fast Open                   
TCP_TIMESTAMP           19100429        Enable TCP timestamps            

Set socket option SO_KEEPALIVE to 1 for sshd process with PID=1062 and tcp socket with FD=3

❯ sudo ./sox set 1062 3 SO_KEEPALIVE 1
SOCKET_OPTION   VALUE   DESCRIPTION                    
SO_KEEPALIVE    1       Enable or disable TCP keepalive

Get value of socket option SO_KEEPALIVE for sshd process with PID=1062 and tcp socket with FD=3

❯ sudo ./sox get 1062 3 SO_KEEPALIVE
SOCKET_OPTION   VALUE   DESCRIPTION                    
SO_KEEPALIVE    0       Enable or disable TCP keepalive