Add support for exporting ipv6 flow label via bpf_flow_keys.
Export flow label from bpf_flow.c and also return early when
FLOW_DISSECTOR_F_STOP_AT_FLOW_LABEL is passed.
Cc: Willem de Bruijn <willemb@xxxxxxxxxx>
Cc: Petar Penkov <ppenkov@xxxxxxxxxx>
Signed-off-by: Stanislav Fomichev <sdf@xxxxxxxxxx>
---
include/uapi/linux/bpf.h | 1 +
net/core/flow_dissector.c | 9 ++++
tools/include/uapi/linux/bpf.h | 1 +
.../selftests/bpf/prog_tests/flow_dissector.c | 46 +++++++++++++++++++
tools/testing/selftests/bpf/progs/bpf_flow.c | 10 ++++
5 files changed, 67 insertions(+)
diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h
index b4ad19bd6aa8..83b4150466af 100644
--- a/include/uapi/linux/bpf.h
+++ b/include/uapi/linux/bpf.h
@@ -3533,6 +3533,7 @@ struct bpf_flow_keys {
};
};
__u32 flags;
+ __be32 flow_label;
};
struct bpf_func_info {
diff --git a/net/core/flow_dissector.c b/net/core/flow_dissector.c
index a74c4ed1b30d..bcdb863cad28 100644
--- a/net/core/flow_dissector.c
+++ b/net/core/flow_dissector.c
@@ -737,6 +737,7 @@ static void __skb_flow_bpf_to_target(const struct bpf_flow_keys *flow_keys,
struct flow_dissector_key_basic *key_basic;
struct flow_dissector_key_addrs *key_addrs;
struct flow_dissector_key_ports *key_ports;
+ struct flow_dissector_key_tags *key_tags;
key_control = skb_flow_dissector_target(flow_dissector,
FLOW_DISSECTOR_KEY_CONTROL,
@@ -781,6 +782,14 @@ static void __skb_flow_bpf_to_target(const struct bpf_flow_keys *flow_keys,
key_ports->src = flow_keys->sport;
key_ports->dst = flow_keys->dport;
}
+
+ if (dissector_uses_key(flow_dissector,
+ FLOW_DISSECTOR_KEY_FLOW_LABEL)) {
+ key_tags = skb_flow_dissector_target(flow_dissector,
+ FLOW_DISSECTOR_KEY_FLOW_LABEL,
+ target_container);
+ key_tags->flow_label = ntohl(flow_keys->flow_label);
+ }
}
bool bpf_flow_dissect(struct bpf_prog *prog, struct bpf_flow_dissector *ctx,
diff --git a/tools/include/uapi/linux/bpf.h b/tools/include/uapi/linux/bpf.h
index a0e1c891b56f..c26ca432b1b3 100644
--- a/tools/include/uapi/linux/bpf.h
+++ b/tools/include/uapi/linux/bpf.h
@@ -3530,6 +3530,7 @@ struct bpf_flow_keys {
};
};
__u32 flags;
+ __be32 flow_label;
};
struct bpf_func_info {
diff --git a/tools/testing/selftests/bpf/prog_tests/flow_dissector.c b/tools/testing/selftests/bpf/prog_tests/flow_dissector.c
index 966cb3b06870..1ea921c4cdc0 100644
--- a/tools/testing/selftests/bpf/prog_tests/flow_dissector.c
+++ b/tools/testing/selftests/bpf/prog_tests/flow_dissector.c
@@ -20,6 +20,7 @@
"is_encap=%u/%u " \
"ip_proto=0x%x/0x%x " \
"n_proto=0x%x/0x%x " \
+ "flow_label=0x%x/0x%x " \
"sport=%u/%u " \
"dport=%u/%u\n", \
got.nhoff, expected.nhoff, \
@@ -30,6 +31,7 @@
got.is_encap, expected.is_encap, \
got.ip_proto, expected.ip_proto, \
got.n_proto, expected.n_proto, \
+ got.flow_label, expected.flow_label, \
got.sport, expected.sport, \
got.dport, expected.dport)
@@ -257,6 +259,50 @@ struct test tests[] = {
.is_first_frag = true,
},
},
+ {
+ .name = "ipv6-flow-label",
+ .pkt.ipv6 = {
+ .eth.h_proto = __bpf_constant_htons(ETH_P_IPV6),
+ .iph.nexthdr = IPPROTO_TCP,
+ .iph.payload_len = __bpf_constant_htons(MAGIC_BYTES),
+ .iph.flow_lbl = { 0xb, 0xee, 0xef },
+ .tcp.doff = 5,
+ .tcp.source = 80,
+ .tcp.dest = 8080,
+ },
+ .keys = {
+ .nhoff = ETH_HLEN,
+ .thoff = ETH_HLEN + sizeof(struct ipv6hdr),
+ .addr_proto = ETH_P_IPV6,
+ .ip_proto = IPPROTO_TCP,
+ .n_proto = __bpf_constant_htons(ETH_P_IPV6),
+ .sport = 80,
+ .dport = 8080,
+ .flow_label = __bpf_constant_htonl(0xbeeef),
+ },
+ },
+ {
+ .name = "ipv6-no-flow-label",
+ .pkt.ipv6 = {
+ .eth.h_proto = __bpf_constant_htons(ETH_P_IPV6),
+ .iph.nexthdr = IPPROTO_TCP,
+ .iph.payload_len = __bpf_constant_htons(MAGIC_BYTES),
+ .iph.flow_lbl = { 0xb, 0xee, 0xef },
+ .tcp.doff = 5,
+ .tcp.source = 80,
+ .tcp.dest = 8080,
+ },
+ .keys = {
+ .flags = FLOW_DISSECTOR_F_STOP_AT_FLOW_LABEL,
+ .nhoff = ETH_HLEN,
+ .thoff = ETH_HLEN + sizeof(struct ipv6hdr),
+ .addr_proto = ETH_P_IPV6,
+ .ip_proto = IPPROTO_TCP,
+ .n_proto = __bpf_constant_htons(ETH_P_IPV6),
+ .flow_label = __bpf_constant_htonl(0xbeeef),
+ },
+ .flags = FLOW_DISSECTOR_F_STOP_AT_FLOW_LABEL,
+ },
};
static int create_tap(const char *ifname)
diff --git a/tools/testing/selftests/bpf/progs/bpf_flow.c b/tools/testing/selftests/bpf/progs/bpf_flow.c
index 0eabe5e57944..7d73b7bfe609 100644
--- a/tools/testing/selftests/bpf/progs/bpf_flow.c
+++ b/tools/testing/selftests/bpf/progs/bpf_flow.c
@@ -83,6 +83,12 @@ static __always_inline int export_flow_keys(struct bpf_flow_keys *keys,
return ret;
}
+#define IPV6_FLOWLABEL_MASK __bpf_constant_htonl(0x000FFFFF)
+static inline __be32 ip6_flowlabel(const struct ipv6hdr *hdr)
+{
+ return *(__be32 *)hdr & IPV6_FLOWLABEL_MASK;
+}
+
static __always_inline void *bpf_flow_dissect_get_header(struct __sk_buff *skb,
__u16 hdr_size,
void *buffer)
@@ -307,6 +313,10 @@ PROG(IPV6)(struct __sk_buff *skb)
keys->thoff += sizeof(struct ipv6hdr);
keys->ip_proto = ip6h->nexthdr;
+ keys->flow_label = ip6_flowlabel(ip6h);
+
+ if (keys->flags & FLOW_DISSECTOR_F_STOP_AT_FLOW_LABEL)
+ return export_flow_keys(keys, BPF_OK);
return parse_ipv6_proto(skb, ip6h->nexthdr);
}
--
2.22.0.657.g960e92d24f-goog
