Currently the only opportunity to set sock ops flags dictating which callbacks fire for a socket is from within a TCP-BPF sockops program. This is problematic if the connection is already set up as there is no further chance to specify callbacks for that socket. Add TCP_BPF_SOCK_OPS_CB_FLAGS to bpf_setsockopt() and bpf_getsockopt() to allow users to specify callbacks later, either via an iterator over sockets or via a socket-specific program triggered by a setsockopt() on the socket. Previous discussion on this here [1]. [1] https://lore.kernel.org/bpf/f42f157b-6e52-dd4d-3d97-9b86c84c0b00@xxxxxxxxxx/ Signed-off-by: Alan Maguire <alan.maguire@xxxxxxxxxx> --- include/uapi/linux/bpf.h | 3 ++- net/core/filter.c | 16 ++++++++++++++++ tools/include/uapi/linux/bpf.h | 3 ++- 3 files changed, 20 insertions(+), 2 deletions(-) diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h index 35bcf52dbc65..d4d7efc34e67 100644 --- a/include/uapi/linux/bpf.h +++ b/include/uapi/linux/bpf.h @@ -2851,7 +2851,7 @@ union bpf_attr { * **TCP_SYNCNT**, **TCP_USER_TIMEOUT**, **TCP_NOTSENT_LOWAT**, * **TCP_NODELAY**, **TCP_MAXSEG**, **TCP_WINDOW_CLAMP**, * **TCP_THIN_LINEAR_TIMEOUTS**, **TCP_BPF_DELACK_MAX**, - * **TCP_BPF_RTO_MIN**. + * **TCP_BPF_RTO_MIN**, **TCP_BPF_SOCK_OPS_CB_FLAGS**. * * **IPPROTO_IP**, which supports *optname* **IP_TOS**. * * **IPPROTO_IPV6**, which supports the following *optname*\ s: * **IPV6_TCLASS**, **IPV6_AUTOFLOWLABEL**. @@ -7080,6 +7080,7 @@ enum { TCP_BPF_SYN = 1005, /* Copy the TCP header */ TCP_BPF_SYN_IP = 1006, /* Copy the IP[46] and TCP header */ TCP_BPF_SYN_MAC = 1007, /* Copy the MAC, IP[46], and TCP header */ + TCP_BPF_SOCK_OPS_CB_FLAGS = 1008, /* Set TCP sock ops flags */ }; enum { diff --git a/net/core/filter.c b/net/core/filter.c index 78a6f746ea0b..570ca3f12175 100644 --- a/net/core/filter.c +++ b/net/core/filter.c @@ -5278,6 +5278,11 @@ static int bpf_sol_tcp_setsockopt(struct sock *sk, int optname, return -EINVAL; inet_csk(sk)->icsk_rto_min = timeout; break; + case TCP_BPF_SOCK_OPS_CB_FLAGS: + if (val & ~(BPF_SOCK_OPS_ALL_CB_FLAGS)) + return -EINVAL; + tp->bpf_sock_ops_cb_flags = val; + break; default: return -EINVAL; } @@ -5366,6 +5371,17 @@ static int sol_tcp_sockopt(struct sock *sk, int optname, if (*optlen < 1) return -EINVAL; break; + case TCP_BPF_SOCK_OPS_CB_FLAGS: + if (*optlen != sizeof(int)) + return -EINVAL; + if (getopt) { + struct tcp_sock *tp = tcp_sk(sk); + int val = READ_ONCE(tp->bpf_sock_ops_cb_flags); + + memcpy(optval, &val, *optlen); + return 0; + } + return bpf_sol_tcp_setsockopt(sk, optname, optval, *optlen); default: if (getopt) return -EINVAL; diff --git a/tools/include/uapi/linux/bpf.h b/tools/include/uapi/linux/bpf.h index 35bcf52dbc65..d4d7efc34e67 100644 --- a/tools/include/uapi/linux/bpf.h +++ b/tools/include/uapi/linux/bpf.h @@ -2851,7 +2851,7 @@ union bpf_attr { * **TCP_SYNCNT**, **TCP_USER_TIMEOUT**, **TCP_NOTSENT_LOWAT**, * **TCP_NODELAY**, **TCP_MAXSEG**, **TCP_WINDOW_CLAMP**, * **TCP_THIN_LINEAR_TIMEOUTS**, **TCP_BPF_DELACK_MAX**, - * **TCP_BPF_RTO_MIN**. + * **TCP_BPF_RTO_MIN**, **TCP_BPF_SOCK_OPS_CB_FLAGS**. * * **IPPROTO_IP**, which supports *optname* **IP_TOS**. * * **IPPROTO_IPV6**, which supports the following *optname*\ s: * **IPV6_TCLASS**, **IPV6_AUTOFLOWLABEL**. @@ -7080,6 +7080,7 @@ enum { TCP_BPF_SYN = 1005, /* Copy the TCP header */ TCP_BPF_SYN_IP = 1006, /* Copy the IP[46] and TCP header */ TCP_BPF_SYN_MAC = 1007, /* Copy the MAC, IP[46], and TCP header */ + TCP_BPF_SOCK_OPS_CB_FLAGS = 1008, /* Set TCP sock ops flags */ }; enum { -- 2.31.1
