bpf: add bpf_get_hash_recalc helper

[linux] / net / core / filter.c

diff --git a/net/core/filter.c b/net/core/filter.c
index 54071cf..10c4a2f 100644 (file)
--- a/net/core/filter.c
+++ b/net/core/filter.c
@@ -1729,6 +1729,23 @@ static const struct bpf_func_proto bpf_get_route_realm_proto = {
        .arg1_type      = ARG_PTR_TO_CTX,
 };
 
+static u64 bpf_get_hash_recalc(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5)
+{
+       /* If skb_clear_hash() was called due to mangling, we can
+        * trigger SW recalculation here. Later access to hash
+        * can then use the inline skb->hash via context directly
+        * instead of calling this helper again.
+        */
+       return skb_get_hash((struct sk_buff *) (unsigned long) r1);
+}
+
+static const struct bpf_func_proto bpf_get_hash_recalc_proto = {
+       .func           = bpf_get_hash_recalc,
+       .gpl_only       = false,
+       .ret_type       = RET_INTEGER,
+       .arg1_type      = ARG_PTR_TO_CTX,
+};
+
 static u64 bpf_skb_vlan_push(u64 r1, u64 r2, u64 vlan_tci, u64 r4, u64 r5)
 {
        struct sk_buff *skb = (struct sk_buff *) (long) r1;
@@ -2337,6 +2354,8 @@ tc_cls_act_func_proto(enum bpf_func_id func_id)
                return &bpf_redirect_proto;
        case BPF_FUNC_get_route_realm:
                return &bpf_get_route_realm_proto;
+       case BPF_FUNC_get_hash_recalc:
+               return &bpf_get_hash_recalc_proto;
        case BPF_FUNC_perf_event_output:
                return bpf_get_event_output_proto();
        case BPF_FUNC_get_smp_processor_id: