Jakub, thanks for your comments.
> 在 2020年6月5日，下午10:53，Jakub Sitnicki <jakub@xxxxxxxxxxxxxx> 写道：
>
> 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 */
