bpf: add napi_id read access to __sk_buff (b1d9fc41) · Commits · 戴 / test

Add napi_id access to __sk_buff for socket filter program types, tc program types and other bpf_convert_ctx_access() users. Having access to skb->napi_id is useful for per RX queue listener siloing, f.e. in combination with SO_ATTACH_REUSEPORT_EBPF and when busy polling is used, meaning SO_REUSEPORT enabled listeners can then select the corresponding socket at SYN time already [1]. The skb is marked via skb_mark_napi_id() early in the receive path (e.g., napi_gro_receive()). Currently, sockets can only use SO_INCOMING_NAPI_ID from ("net: Introduce SO_INCOMING_NAPI_ID") as a socket option to look up the NAPI ID associated with the queue for steering, which requires a prior sk_mark_napi_id() after the socket was looked up. Semantics for the __sk_buff napi_id access are similar, meaning if skb->napi_id is < MIN_NAPI_ID (e.g. outgoing packets using sender_cpu), then an invalid napi_id of 0 is returned to the program, otherwise a valid non-zero napi_id. [1] http://netdevconf.org/2.1/slides/apr6/dumazet-BUSY-POLLING-Netdev-2.1.pdf Suggested-by:

Eric Dumazet <edumazet@google.com> Signed-off-by:

Daniel Borkmann <daniel@iogearbox.net> Acked-by:

Alexei Starovoitov <ast@kernel.org> Signed-off-by:

David S. Miller <davem@davemloft.net>

include/uapi/linux/bpf.h

+1 −0

Original line number	Diff line number	Diff line
		@@ -603,6 +603,7 @@ struct __sk_buff {
		__u32 tc_classid;
		__u32 data;
		__u32 data_end;
		__u32 napi_id;
		};

		struct bpf_tunnel_key {

net/core/filter.c

+14 −0

Original line number	Diff line number	Diff line
		@@ -53,6 +53,7 @@
		#include <net/dst_metadata.h>
		#include <net/dst.h>
		#include <net/sock_reuseport.h>
		#include <net/busy_poll.h>

		/**
		* sk_filter_trim_cap - run a packet through a socket filter
		@@ -3201,6 +3202,19 @@ static u32 bpf_convert_ctx_access(enum bpf_access_type type,
		*insn++ = BPF_MOV64_REG(si->dst_reg, si->dst_reg);
		else
		*insn++ = BPF_MOV64_IMM(si->dst_reg, 0);
		#endif
		break;

		case offsetof(struct __sk_buff, napi_id):
		#if defined(CONFIG_NET_RX_BUSY_POLL)
		BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, napi_id) != 4);

		*insn++ = BPF_LDX_MEM(BPF_W, si->dst_reg, si->src_reg,
		offsetof(struct sk_buff, napi_id));
		*insn++ = BPF_JMP_IMM(BPF_JGE, si->dst_reg, MIN_NAPI_ID, 1);
		*insn++ = BPF_MOV64_IMM(si->dst_reg, 0);
		#else
		*insn++ = BPF_MOV64_IMM(si->dst_reg, 0);
		#endif
		break;
		}

tools/include/uapi/linux/bpf.h

+1 −0

Original line number	Diff line number	Diff line
		@@ -603,6 +603,7 @@ struct __sk_buff {
		__u32 tc_classid;
		__u32 data;
		__u32 data_end;
		__u32 napi_id;
		};

		struct bpf_tunnel_key {

tools/testing/selftests/bpf/test_verifier.c

+3 −0

Original line number	Diff line number	Diff line
		@@ -772,6 +772,9 @@ static struct bpf_test tests[] = {
		BPF_LDX_MEM(BPF_W, BPF_REG_0, BPF_REG_1,
		offsetof(struct __sk_buff, vlan_tci)),
		BPF_JMP_IMM(BPF_JGE, BPF_REG_0, 0, 0),
		BPF_LDX_MEM(BPF_W, BPF_REG_0, BPF_REG_1,
		offsetof(struct __sk_buff, napi_id)),
		BPF_JMP_IMM(BPF_JGE, BPF_REG_0, 0, 0),
		BPF_EXIT_INSN(),
		},
		.result = ACCEPT,

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