Hi, I was looking through the congestion control algorithms in net/ipv4. I noticed that TCP BBR is the only other algorithm besides Reno to be marked TCP_CONG_NON_RESTRICTED (see net/ipv4/tcp_bbr.c:1141 and net/ipv4/tcp_cong.c:476). This basically allows BBR to be set for individual sockets by unprivileged users by default. Normally, control algorithms need to be manually added to sysctl's net.ipv4.tcp_allowed_congestion_control by the admin. I'm wondering, why does BBR get special treatment here? It doesn't seem particularly more secure to allow this for BBR than for Cubic, Vegas, or any other algorithms. Best, Taran
