bpf: Support BPF_FUNC_get_socket_cookie() for BPF_PROG_TYPE_SK_REUSEPORT.

We will call sock_reuseport.prog for socket migration in the next commit,
so the eBPF program has to know which listener is closing to select a new
listener.

We can currently get a unique ID of each listener in the userspace by
calling bpf_map_lookup_elem() for BPF_MAP_TYPE_REUSEPORT_SOCKARRAY map.

This patch makes the pointer of sk available in sk_reuseport_md so that we
can get the ID by BPF_FUNC_get_socket_cookie() in the eBPF program.

Suggested-by: Martin KaFai Lau <kafai@fb.com>
Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.co.jp>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Acked-by: Martin KaFai Lau <kafai@fb.com>
Link: https://lore.kernel.org/netdev/20201119001154.kapwihc2plp4f7zc@kafai-mbp.dhcp.thefacebook.com/
Link: https://lore.kernel.org/bpf/20210612123224.12525-9-kuniyu@amazon.co.jp

diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h
index 2c1ba70abbf10e97ff7c85fb6d2d0b87f14fb7be..f3b72588442be2a38f5d174a98ce3b1e90244188 100644 (file)
--- a/include/uapi/linux/bpf.h
+++ b/include/uapi/linux/bpf.h
@@ -5416,6 +5416,7 @@ 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 */
+       __bpf_md_ptr(struct bpf_sock *, sk);
 };
 
 #define BPF_TAG_SIZE   8

diff --git a/net/core/filter.c b/net/core/filter.c
index caa88955562e9af71e5807327517a346e04db54e..f753ab550525eb2643c86ca01d2b2e6540f2a4bd 100644 (file)
--- a/net/core/filter.c
+++ b/net/core/filter.c
@@ -10172,6 +10172,8 @@ sk_reuseport_func_proto(enum bpf_func_id func_id,
                return &sk_reuseport_load_bytes_proto;
        case BPF_FUNC_skb_load_bytes_relative:
                return &sk_reuseport_load_bytes_relative_proto;
+       case BPF_FUNC_get_socket_cookie:
+               return &bpf_get_socket_ptr_cookie_proto;
        default:
                return bpf_base_func_proto(func_id);
        }
@@ -10201,6 +10203,10 @@ sk_reuseport_is_valid_access(int off, int size,
        case offsetof(struct sk_reuseport_md, hash):
                return size == size_default;
 
+       case offsetof(struct sk_reuseport_md, sk):
+               info->reg_type = PTR_TO_SOCKET;
+               return size == sizeof(__u64);
+
        /* Fields that allow narrowing */
        case bpf_ctx_range(struct sk_reuseport_md, eth_protocol):
                if (size < sizeof_field(struct sk_buff, protocol))
@@ -10273,6 +10279,10 @@ 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, sk):
+               SK_REUSEPORT_LOAD_FIELD(sk);
+               break;
        }
 
        return insn - insn_buf;

diff --git a/tools/include/uapi/linux/bpf.h b/tools/include/uapi/linux/bpf.h
index 2c1ba70abbf10e97ff7c85fb6d2d0b87f14fb7be..f3b72588442be2a38f5d174a98ce3b1e90244188 100644 (file)
--- a/tools/include/uapi/linux/bpf.h
+++ b/tools/include/uapi/linux/bpf.h
@@ -5416,6 +5416,7 @@ 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 */
+       __bpf_md_ptr(struct bpf_sock *, sk);
 };
 
 #define BPF_TAG_SIZE   8