On Fri, Jun 05, 2020 at 02:40 PM CEST, Wang Li wrote:
> Sometimes we need net namespace as part of the key for BPF_MAP_TYPE_SOCKHASH to
> distinguish the connections with same five-tuples, for example when we do the
> sock_map acceleration for the proxy that uses 127.0.0.1 to 127.0.0.1 connections
> in different containers on same node.
> And we export the netns inum instead of the real pointer of struct net to avoid
> the potential security issue.
>
> Signed-off-by: Wang Li <wangli09@xxxxxxxxxxxx>
> Signed-off-by: huangxuesen <huangxuesen@xxxxxxxxxxxx>
> Signed-off-by: yangxingwu <yangxingwu@xxxxxxxxxxxx>
> ---
> include/uapi/linux/bpf.h | 2 ++
> net/core/filter.c | 17 +++++++++++++++++
> tools/include/uapi/linux/bpf.h | 2 ++
> 3 files changed, 21 insertions(+)
>
> diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h
> index c65b374a5090..0fe7e459f023 100644
> --- a/include/uapi/linux/bpf.h
> +++ b/include/uapi/linux/bpf.h
> @@ -3947,6 +3947,8 @@ struct bpf_sock_ops {
> * there is a full socket. If not, the
> * fields read as zero.
> */
> + __u32 netns_inum; /* The net namespace this sock belongs to */
> +
In uapi/linux/bpf.h we have a field `netns_ino` for storing net
namespace inode number in a couple structs (bpf_prog_info,
bpf_map_info). Would be nice to keep the naming constent.
> __u32 snd_cwnd;
> __u32 srtt_us; /* Averaged RTT << 3 in usecs */
> __u32 bpf_sock_ops_cb_flags; /* flags defined in uapi/linux/tcp.h */
> diff --git a/net/core/filter.c b/net/core/filter.c
> index d01a244b5087..bfe448ace25f 100644
> --- a/net/core/filter.c
> +++ b/net/core/filter.c
> @@ -8450,6 +8450,23 @@ static u32 sock_ops_convert_ctx_access(enum bpf_access_type type,
> is_fullsock));
> break;
>
> + case offsetof(struct bpf_sock_ops, netns_inum):
> +#ifdef CONFIG_NET_NS
> + *insn++ = BPF_LDX_MEM(BPF_FIELD_SIZEOF(
> + struct bpf_sock_ops_kern, sk),
> + si->dst_reg, si->src_reg,
> + offsetof(struct bpf_sock_ops_kern, sk));
> + *insn++ = BPF_LDX_MEM(BPF_FIELD_SIZEOF(
> + struct sock_common, skc_net),
> + si->dst_reg, si->dst_reg,
> + offsetof(struct sock_common, skc_net));
> + *insn++ = BPF_LDX_MEM(BPF_W, si->dst_reg, si->dst_reg,
> + offsetof(struct net, ns.inum));
> +#else
> + *insn++ = BPF_MOV32_IMM(si->dst_reg, 0);
> +#endif
> + break;
> +
> case offsetof(struct bpf_sock_ops, state):
> BUILD_BUG_ON(sizeof_field(struct sock_common, skc_state) != 1);
>
> diff --git a/tools/include/uapi/linux/bpf.h b/tools/include/uapi/linux/bpf.h
> index c65b374a5090..0fe7e459f023 100644
> --- a/tools/include/uapi/linux/bpf.h
> +++ b/tools/include/uapi/linux/bpf.h
> @@ -3947,6 +3947,8 @@ struct bpf_sock_ops {
> * there is a full socket. If not, the
> * fields read as zero.
> */
> + __u32 netns_inum; /* The net namespace this sock belongs to */
> +
> __u32 snd_cwnd;
> __u32 srtt_us; /* Averaged RTT << 3 in usecs */
> __u32 bpf_sock_ops_cb_flags; /* flags defined in uapi/linux/tcp.h */
