[PATCH bpf-next 09/11] bpf: Add BPF_SOCK_OPS_RETRANS_CB
From: Lawrence Brakmo <hidden>
Date: 2017-12-20 21:16:58
Subsystem:
bpf [general] (safe dynamic programs and tools), networking [general], networking [tcp], the rest · Maintainers:
Alexei Starovoitov, Daniel Borkmann, Andrii Nakryiko, Eduard Zingerman, Kumar Kartikeya Dwivedi, "David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Neal Cardwell, Linus Torvalds
Adds support for calling sock_ops BPF program when there is a retransmission. Two arguments are used; one for the sequence number and other for the number of segments retransmitted. Does not include syn-ack retransmissions. New op: BPF_SOCK_OPS_RETRANS_CB. Signed-off-by: Lawrence Brakmo <redacted> --- include/uapi/linux/bpf.h | 4 ++++ include/uapi/linux/tcp.h | 1 + net/ipv4/tcp_output.c | 3 +++ 3 files changed, 8 insertions(+)
diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h
index 5bead0e..415b951 100644
--- a/include/uapi/linux/bpf.h
+++ b/include/uapi/linux/bpf.h@@ -1020,6 +1020,10 @@ enum { * Arg2: value of icsk_rto * Arg3: whether RTO has expired */ + BPF_SOCK_OPS_RETRANS_CB, /* Called when skb is retransmitted. + * Arg1: sequence number of 1st byte + * Arg2: # segments + */ }; #define TCP_BPF_IW 1001 /* Set TCP initial congestion window */
diff --git a/include/uapi/linux/tcp.h b/include/uapi/linux/tcp.h
index 089c19e..dc36d3c 100644
--- a/include/uapi/linux/tcp.h
+++ b/include/uapi/linux/tcp.h@@ -261,6 +261,7 @@ struct tcp_md5sig { /* Definitions for bpf_sock_ops_flags */ #define BPF_SOCK_OPS_RTO_CB_FLAG (1<<0) +#define BPF_SOCK_OPS_RETRANS_CB_FLAG (1<<1) /* INET_DIAG_MD5SIG */ struct tcp_diag_md5sig {
diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c
index b093985..8109675 100644
--- a/net/ipv4/tcp_output.c
+++ b/net/ipv4/tcp_output.c@@ -2907,6 +2907,9 @@ int __tcp_retransmit_skb(struct sock *sk, struct sk_buff *skb, int segs) if (likely(!err)) { TCP_SKB_CB(skb)->sacked |= TCPCB_EVER_RETRANS; trace_tcp_retransmit_skb(sk, skb); + if (BPF_SOCK_OPS_TEST_FLAG(tp, BPF_SOCK_OPS_RETRANS_CB_FLAG)) + tcp_call_bpf_2arg(sk, BPF_SOCK_OPS_RETRANS_CB, + TCP_SKB_CB(skb)->seq, segs); } else if (err != -EBUSY) { NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPRETRANSFAIL); }
--
2.9.5