netdev - [PATCH net-next 5/6] bpf: Fix tcp_iw

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Message-ID: <20171110204303.1840413-6-brakmo@fb.com>
Date:   Fri, 10 Nov 2017 12:43:02 -0800
From:   Lawrence Brakmo <brakmo@...com>
To:     netdev <netdev@...r.kernel.org>
CC:     Alexei Starovoitov <ast@...com>,
        Daniel Borkmann <daniel@...earbox.net>
Subject: [PATCH net-next 5/6] bpf: Fix tcp_iw_kern.c sample program

The program was returning -1 in some cases which is not allowed
by the verifier any longer.

Fixes: 7bc62e285479 ("bpf: Sample BPF program to set initial cwnd")
Signed-off-by: Lawrence Brakmo <brakmo@...com>
---
 samples/bpf/tcp_iw_kern.c | 14 ++++++++------
 1 file changed, 8 insertions(+), 6 deletions(-)

diff --git a/samples/bpf/tcp_iw_kern.c b/samples/bpf/tcp_iw_kern.c
index 23c5122..4ca5ecc 100644
--- a/samples/bpf/tcp_iw_kern.c
+++ b/samples/bpf/tcp_iw_kern.c
@@ -42,8 +42,10 @@ int bpf_iw(struct bpf_sock_ops *skops)
 	 * if neither port numberis 55601
 	 */
 	if (bpf_ntohl(skops->remote_port) != 55601 &&
-	    skops->local_port != 55601)
-		return -1;
+	    skops->local_port != 55601) {
+		skops->reply = -1;
+		return 1;
+	}
 
 	op = (int) skops->op;
 
@@ -62,8 +64,8 @@ int bpf_iw(struct bpf_sock_ops *skops)
 		/* Set sndbuf and rcvbuf of active connections */
 		rv = bpf_setsockopt(skops, SOL_SOCKET, SO_SNDBUF, &bufsize,
 				    sizeof(bufsize));
-		rv = rv*100 + bpf_setsockopt(skops, SOL_SOCKET, SO_RCVBUF,
-					     &bufsize, sizeof(bufsize));
+		rv += bpf_setsockopt(skops, SOL_SOCKET, SO_RCVBUF,
+				     &bufsize, sizeof(bufsize));
 		break;
 	case BPF_SOCK_OPS_ACTIVE_ESTABLISHED_CB:
 		rv = bpf_setsockopt(skops, SOL_TCP, TCP_BPF_IW, &iw,
@@ -73,8 +75,8 @@ int bpf_iw(struct bpf_sock_ops *skops)
 		/* Set sndbuf and rcvbuf of passive connections */
 		rv = bpf_setsockopt(skops, SOL_SOCKET, SO_SNDBUF, &bufsize,
 				    sizeof(bufsize));
-		rv = rv*100 + bpf_setsockopt(skops, SOL_SOCKET, SO_RCVBUF,
-					     &bufsize, sizeof(bufsize));
+		rv +=  bpf_setsockopt(skops, SOL_SOCKET, SO_RCVBUF,
+				      &bufsize, sizeof(bufsize));
 		break;
 	default:
 		rv = -1;
-- 
2.9.5