Re: [bpf-next PATCH 3/3] bpf: sk_msg add get socket storage helpers

[Yonghong Song]

On 5/13/20 12:24 PM, John Fastabend wrote:

Add helpers to use local socket storage.

Signed-off-by: John Fastabend <john.fastab...@gmail.com>
---
  include/uapi/linux/bpf.h |    2 ++
  net/core/filter.c        |   15 +++++++++++++++
  2 files changed, 17 insertions(+)

diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h
index bfb31c1..3ca7cfd 100644
--- a/include/uapi/linux/bpf.h
+++ b/include/uapi/linux/bpf.h
@@ -3607,6 +3607,8 @@ struct sk_msg_md {
        __u32 remote_port;      /* Stored in network byte order */
        __u32 local_port;       /* stored in host byte order */
        __u32 size;             /* Total size of sk_msg */
+
+       __bpf_md_ptr(struct bpf_sock *, sk); /* current socket */
  };

Sync changes to tools/include/uapi/linux/bpf.h?

For this patch and previous patches, it would be good we got some
selftests to exercise some newly-added helpers.

struct sk_reuseport_md {

diff --git a/net/core/filter.c b/net/core/filter.c
index d1c4739..c42adc8 100644
--- a/net/core/filter.c
+++ b/net/core/filter.c
@@ -6395,6 +6395,10 @@ sk_msg_func_proto(enum bpf_func_id func_id, const struct 
bpf_prog *prog)
                return &bpf_get_current_uid_gid_proto;
        case BPF_FUNC_get_current_pid_tgid:
                return &bpf_get_current_pid_tgid_proto;
+       case BPF_FUNC_sk_storage_get:
+               return &bpf_sk_storage_get_proto;
+       case BPF_FUNC_sk_storage_delete:
+               return &bpf_sk_storage_delete_proto;
  #ifdef CONFIG_CGROUPS
        case BPF_FUNC_get_current_cgroup_id:
                return &bpf_get_current_cgroup_id_proto;
@@ -7243,6 +7247,11 @@ static bool sk_msg_is_valid_access(int off, int size,
                if (size != sizeof(__u64))
                        return false;
                break;
+       case offsetof(struct sk_msg_md, sk):
+               if (size != sizeof(__u64))
+                       return false;
+               info->reg_type = PTR_TO_SOCKET;
+               break;
        case bpf_ctx_range(struct sk_msg_md, family):
        case bpf_ctx_range(struct sk_msg_md, remote_ip4):
        case bpf_ctx_range(struct sk_msg_md, local_ip4):
@@ -8577,6 +8586,12 @@ static u32 sk_msg_convert_ctx_access(enum 
bpf_access_type type,
                                      si->dst_reg, si->src_reg,
                                      offsetof(struct sk_msg_sg, size));
                break;
+
+       case offsetof(struct sk_msg_md, sk):
+               *insn++ = BPF_LDX_MEM(BPF_FIELD_SIZEOF(struct sk_msg, sk),
+                                     si->dst_reg, si->src_reg,
+                                     offsetof(struct sk_msg, sk));
+               break;
        }

return insn - insn_buf;