[PATCH v2 bpf-next 10/13] bpf: Add migration to sk_reuseport_(kern|md).

From: Kuniyuki Iwashima <hidden>
Date: 2020-12-07 13:29:06
Also in: bpf, lkml
Subsystem: bpf [core], bpf [general] (safe dynamic programs and tools), bpf [networking] (tcx & tc bpf, sock_addr), networking [general], networking [sockets], the rest · Maintainers: Alexei Starovoitov, Daniel Borkmann, Andrii Nakryiko, Eduard Zingerman, Kumar Kartikeya Dwivedi, "David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Kuniyuki Iwashima, Willem de Bruijn, Linus Torvalds

This patch adds u8 migration field to sk_reuseport_kern and sk_reuseport_md
to signal the eBPF program if the kernel calls it for selecting a listener
for SYN or migrating sockets in the accept queue or an immature socket
during 3WHS.

Note that this field is accessible only if the attached type is
BPF_SK_REUSEPORT_SELECT_OR_MIGRATE.

Link: https://lore.kernel.org/netdev/20201123003828.xjpjdtk4ygl6tg6h@kafai-mbp.dhcp.thefacebook.com/ (local)
Suggested-by: Martin KaFai Lau <redacted>
Signed-off-by: Kuniyuki Iwashima <redacted>
---
 include/linux/bpf.h            |  1 +
 include/linux/filter.h         |  4 ++--
 include/uapi/linux/bpf.h       |  1 +
 net/core/filter.c              | 15 ++++++++++++---
 net/core/sock_reuseport.c      |  2 +-
 tools/include/uapi/linux/bpf.h |  1 +
 6 files changed, 18 insertions(+), 6 deletions(-)

diff --git a/include/linux/bpf.h b/include/linux/bpf.h
index d05e75ed8c1b..cdeb27f4ad63 100644
--- a/include/linux/bpf.h
+++ b/include/linux/bpf.h

@@ -1914,6 +1914,7 @@ struct sk_reuseport_kern {
 	u32 hash;
 	u32 reuseport_id;
 	bool bind_inany;
+	u8 migration;
 };
 bool bpf_tcp_sock_is_valid_access(int off, int size, enum bpf_access_type type,
 				  struct bpf_insn_access_aux *info);

diff --git a/include/linux/filter.h b/include/linux/filter.h
index 1b62397bd124..15d5bf13a905 100644
--- a/include/linux/filter.h
+++ b/include/linux/filter.h

@@ -967,12 +967,12 @@ void bpf_warn_invalid_xdp_action(u32 act);
 #ifdef CONFIG_INET
 struct sock *bpf_run_sk_reuseport(struct sock_reuseport *reuse, struct sock *sk,
 				  struct bpf_prog *prog, struct sk_buff *skb,
-				  u32 hash);
+				  u32 hash, u8 migration);
 #else
 static inline struct sock *
 bpf_run_sk_reuseport(struct sock_reuseport *reuse, struct sock *sk,
 		     struct bpf_prog *prog, struct sk_buff *skb,
-		     u32 hash)
+		     u32 hash, u8 migration)
 {
 	return NULL;
 }

diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h
index c7f6848c0226..cf518e83df5c 100644
--- a/include/uapi/linux/bpf.h
+++ b/include/uapi/linux/bpf.h

@@ -4462,6 +4462,7 @@ struct sk_reuseport_md {
 	__u32 ip_protocol;	/* IP protocol. e.g. IPPROTO_TCP, IPPROTO_UDP */
 	__u32 bind_inany;	/* Is sock bound to an INANY address? */
 	__u32 hash;		/* A hash of the packet 4 tuples */
+	__u8 migration;		/* Migration type */
 };
 
 #define BPF_TAG_SIZE	8

diff --git a/net/core/filter.c b/net/core/filter.c
index 77001a35768f..7bdf62f24044 100644
--- a/net/core/filter.c
+++ b/net/core/filter.c

@@ -9860,7 +9860,7 @@ int sk_get_filter(struct sock *sk, struct sock_filter __user *ubuf,
 static void bpf_init_reuseport_kern(struct sk_reuseport_kern *reuse_kern,
 				    struct sock_reuseport *reuse,
 				    struct sock *sk, struct sk_buff *skb,
-				    u32 hash)
+				    u32 hash, u8 migration)
 {
 	reuse_kern->skb = skb;
 	reuse_kern->sk = sk;

@@ -9869,16 +9869,17 @@ static void bpf_init_reuseport_kern(struct sk_reuseport_kern *reuse_kern,
 	reuse_kern->hash = hash;
 	reuse_kern->reuseport_id = reuse->reuseport_id;
 	reuse_kern->bind_inany = reuse->bind_inany;
+	reuse_kern->migration = migration;
 }
 
 struct sock *bpf_run_sk_reuseport(struct sock_reuseport *reuse, struct sock *sk,
 				  struct bpf_prog *prog, struct sk_buff *skb,
-				  u32 hash)
+				  u32 hash, u8 migration)
 {
 	struct sk_reuseport_kern reuse_kern;
 	enum sk_action action;
 
-	bpf_init_reuseport_kern(&reuse_kern, reuse, sk, skb, hash);
+	bpf_init_reuseport_kern(&reuse_kern, reuse, sk, skb, hash, migration);
 	action = BPF_PROG_RUN(prog, &reuse_kern);
 
 	if (action == SK_PASS)

@@ -10017,6 +10018,10 @@ sk_reuseport_is_valid_access(int off, int size,
 	case offsetof(struct sk_reuseport_md, hash):
 		return size == size_default;
 
+	case bpf_ctx_range(struct sk_reuseport_md, migration):
+		return prog->expected_attach_type == BPF_SK_REUSEPORT_SELECT_OR_MIGRATE &&
+			size == sizeof(__u8);
+
 	/* Fields that allow narrowing */
 	case bpf_ctx_range(struct sk_reuseport_md, eth_protocol):
 		if (size < sizeof_field(struct sk_buff, protocol))

@@ -10089,6 +10094,10 @@ static u32 sk_reuseport_convert_ctx_access(enum bpf_access_type type,
 	case offsetof(struct sk_reuseport_md, bind_inany):
 		SK_REUSEPORT_LOAD_FIELD(bind_inany);
 		break;
+
+	case offsetof(struct sk_reuseport_md, migration):
+		SK_REUSEPORT_LOAD_FIELD(migration);
+		break;
 	}
 
 	return insn - insn_buf;

diff --git a/net/core/sock_reuseport.c b/net/core/sock_reuseport.c
index 1011c3756c92..b877c8e552d2 100644
--- a/net/core/sock_reuseport.c
+++ b/net/core/sock_reuseport.c

@@ -313,7 +313,7 @@ static struct sock *__reuseport_select_sock(struct sock *sk, u32 hash,
 			goto select_by_hash;
 
 		if (prog->type == BPF_PROG_TYPE_SK_REUSEPORT)
-			sk2 = bpf_run_sk_reuseport(reuse, sk, prog, skb, hash);
+			sk2 = bpf_run_sk_reuseport(reuse, sk, prog, skb, hash, migration);
 		else
 			sk2 = run_bpf_filter(reuse, socks, prog, skb, hdr_len);

diff --git a/tools/include/uapi/linux/bpf.h b/tools/include/uapi/linux/bpf.h
index c7f6848c0226..cf518e83df5c 100644
--- a/tools/include/uapi/linux/bpf.h
+++ b/tools/include/uapi/linux/bpf.h

@@ -4462,6 +4462,7 @@ struct sk_reuseport_md {
 	__u32 ip_protocol;	/* IP protocol. e.g. IPPROTO_TCP, IPPROTO_UDP */
 	__u32 bind_inany;	/* Is sock bound to an INANY address? */
 	__u32 hash;		/* A hash of the packet 4 tuples */
+	__u8 migration;		/* Migration type */
 };
 
 #define BPF_TAG_SIZE	8

-- 
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