Wrong route on macOS

[zhengmian hu]

The macOS version is 11.4 (20F71).
I also found that when the client config contains two peers, one of
them just doesn't work.

zhengmian hu <huzhengmian at gmail.com> 于2021年7月8日周四 上午12:52写道：
>
> I expect no data to be sent to the server when I only visit the local
> address. However, this is not true for wireguard on macOS.
>
> Detailed setup:
> App:
> Downloaded from app store. App version: 1.0.13 (24), Go backend
> version: f9b48a96.
>
> Server:
> ```
> [Interface]
> Address = 10.110.210.1/24
> SaveConfig = true
> ListenPort = 51820
> PrivateKey = xxxxSERVER_PRIVATExxxx
>
> [Peer]
> PublicKey = xxxxCLIENT_PUBLICxxxx
> AllowedIPs = 10.110.210.7/32
> Endpoint = xxxx
> ```
>
> Client:
> ```
> [Interface]
> PrivateKey = xxxxCLIENT_PRIVATExxxx
> Address = 10.110.210.7/32
>
> [Peer]
> PublicKey = xxxxSERVER_PUBLICxxxx
> AllowedIPs = 10.110.210.1/24
> Endpoint = xxxSERVER_IPxxx:51820
> PersistentKeepalive = 25
> ```
>
> Test:
> ```
> ❯ traceroute 10.110.210.7
> traceroute to 10.110.210.7 (10.110.210.7), 64 hops max, 52 byte packets
>  1  10.110.210.1 (10.110.210.1)  22.118 ms  19.846 ms  19.929 ms
>  2  10.110.210.7 (10.110.210.7)  40.627 ms  40.264 ms  43.752 ms
> ```
>
> Route:
> ```
> ❯ netstat -rn -f inet
> Routing tables
>
> Internet:
> Destination        Gateway            Flags        Netif Expire
> default            192.168.0.1        UGScg          en0
> default            link#17            UCSIg        utun2
> 10.110.210/24      link#17            UCS          utun2
> 10.110.210.7       10.110.210.7       UH           utun2
> 127                127.0.0.1          UCS            lo0
> 127.0.0.1          127.0.0.1          UH             lo0
> ...
> 255.255.255.255/32 link#17            UCSI         utun2
> ```
>
> Expected behaviour:
> When using `traceroute 10.110.210.7`, the server `10.110.210.1` doesn't show up.
>
> Other:
> I have tried the same configuration on Windows, and it works fine.