[PATCH v2 bpf-next 05/11] bpf: Adds field bpf_sock_ops_flags to tcp_sock
From: Lawrence Brakmo <hidden>
Date: 2017-12-22 01:21:07
Subsystem:
bpf [general] (safe dynamic programs and tools), bpf [networking] (tcx & tc bpf, sock_addr), networking [general], networking [tcp], the rest · Maintainers:
Alexei Starovoitov, Daniel Borkmann, Andrii Nakryiko, Eduard Zingerman, Kumar Kartikeya Dwivedi, Martin KaFai Lau, "David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Neal Cardwell, Linus Torvalds
Adds field bpf_sock_ops_flags to tcp_sock and bpf_sock_ops. Its primary use is to determine if there should be calls to sock_ops bpf program at various points in the TCP code. The field is initialized to zero, disabling the calls. A sock_ops BPF program can set, per connection and as necessary, when the connection is established. It also adds support for reading and writting the field within a sock_ops BPF program. Examples of where to call the bpf program: 1) When RTO fires 2) When a packet is retransmitted 3) When the connection terminates 4) When a packet is sent 5) When a packet is received Signed-off-by: Lawrence Brakmo <redacted> --- include/linux/tcp.h | 8 ++++++++ include/uapi/linux/bpf.h | 1 + net/core/filter.c | 7 +++++++ 3 files changed, 16 insertions(+)
diff --git a/include/linux/tcp.h b/include/linux/tcp.h
index 4f93f095..62f4388 100644
--- a/include/linux/tcp.h
+++ b/include/linux/tcp.h@@ -373,6 +373,14 @@ struct tcp_sock { */ struct request_sock *fastopen_rsk; u32 *saved_syn; + +/* Sock_ops bpf program related variables */ +#ifdef CONFIG_BPF + u32 bpf_sock_ops_flags; /* values defined in uapi/linux/tcp.h */ +#define BPF_SOCK_OPS_TEST_FLAG(TP, ARG) (TP->bpf_sock_ops_flags & ARG) +#else +#define BPF_SOCK_OPS_TEST_FLAG(TP, ARG) 0 +#endif }; enum tsq_enum {
diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h
index 1fea987..62b2c89 100644
--- a/include/uapi/linux/bpf.h
+++ b/include/uapi/linux/bpf.h@@ -959,6 +959,7 @@ struct bpf_sock_ops { */ __u32 snd_cwnd; __u32 srtt_us; /* Averaged RTT << 3 in usecs */ + __u32 bpf_sock_ops_flags; /* flags defined in uapi/linux/tcp.h */ }; /* List of known BPF sock_ops operators.
diff --git a/net/core/filter.c b/net/core/filter.c
index 978ac78..76fd6e9 100644
--- a/net/core/filter.c
+++ b/net/core/filter.c@@ -3843,6 +3843,7 @@ static bool sock_ops_is_valid_access(int off, int size, switch (off) { case offsetof(struct bpf_sock_ops, op) ... offsetof(struct bpf_sock_ops, replylong[3]): + case offsetof(struct bpf_sock_ops, bpf_sock_ops_flags): break; default: return false;
@@ -4525,6 +4526,12 @@ static u32 sock_ops_convert_ctx_access(enum bpf_access_type type, case offsetof(struct bpf_sock_ops, srtt_us): SOCK_OPS_GET_FIELD(srtt_us, srtt_us, struct tcp_sock); break; + + case offsetof(struct bpf_sock_ops, bpf_sock_ops_flags): + SOCK_OPS_GET_OR_SET_FIELD(bpf_sock_ops_flags, + bpf_sock_ops_flags, + struct tcp_sock, type); + break; } return insn - insn_buf; }
--
2.9.5