[PATCH net-next v2 5/6] bpf: Fix tcp_iw_kern.c sample program

[Lawrence Brakmo]

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

Fixes: 390ee7e29fc8 ("bpf: enforce return code for cgroup-bpf programs")
Signed-off-by: Lawrence Brakmo <bra...@fb.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