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Diffstat (limited to 'tools/testing/selftests/bpf/progs/bpf_dctcp.c')
-rw-r--r--tools/testing/selftests/bpf/progs/bpf_dctcp.c25
1 files changed, 25 insertions, 0 deletions
diff --git a/tools/testing/selftests/bpf/progs/bpf_dctcp.c b/tools/testing/selftests/bpf/progs/bpf_dctcp.c
index fd42247da8b4..9573be6122be 100644
--- a/tools/testing/selftests/bpf/progs/bpf_dctcp.c
+++ b/tools/testing/selftests/bpf/progs/bpf_dctcp.c
@@ -17,6 +17,11 @@
char _license[] SEC("license") = "GPL";
+volatile const char fallback[TCP_CA_NAME_MAX];
+const char bpf_dctcp[] = "bpf_dctcp";
+const char tcp_cdg[] = "cdg";
+char cc_res[TCP_CA_NAME_MAX];
+int tcp_cdg_res = 0;
int stg_result = 0;
struct {
@@ -57,6 +62,26 @@ void BPF_PROG(dctcp_init, struct sock *sk)
struct dctcp *ca = inet_csk_ca(sk);
int *stg;
+ if (!(tp->ecn_flags & TCP_ECN_OK) && fallback[0]) {
+ /* Switch to fallback */
+ bpf_setsockopt(sk, SOL_TCP, TCP_CONGESTION,
+ (void *)fallback, sizeof(fallback));
+ /* Switch back to myself which the bpf trampoline
+ * stopped calling dctcp_init recursively.
+ */
+ bpf_setsockopt(sk, SOL_TCP, TCP_CONGESTION,
+ (void *)bpf_dctcp, sizeof(bpf_dctcp));
+ /* Switch back to fallback */
+ bpf_setsockopt(sk, SOL_TCP, TCP_CONGESTION,
+ (void *)fallback, sizeof(fallback));
+ /* Expecting -ENOTSUPP for tcp_cdg_res */
+ tcp_cdg_res = bpf_setsockopt(sk, SOL_TCP, TCP_CONGESTION,
+ (void *)tcp_cdg, sizeof(tcp_cdg));
+ bpf_getsockopt(sk, SOL_TCP, TCP_CONGESTION,
+ (void *)cc_res, sizeof(cc_res));
+ return;
+ }
+
ca->prior_rcv_nxt = tp->rcv_nxt;
ca->dctcp_alpha = min(dctcp_alpha_on_init, DCTCP_MAX_ALPHA);
ca->loss_cwnd = 0;