Re: [PATCH v2] net: fix multicast support with BSD (macOS) socket implementations

[Jason Wang]

On Tue, May 31, 2022 at 7:28 PM Vitaly Cheptsov <cheptsov@ispras.ru> wrote:
>
> Hi Jason,
>
> This patch fixes socket communication with QEMU -> host and QEMU <--> QEMU on 
> macOS, which was originally impossible due to QEMU and host program having to 
> bind to the same ip/port in a way not supported by BSD sockets. The change 
> was tested on both Linux and macOS.
>
> Basically after applying this patch one will be able to communicate with QEMU 
> when using "-nic socket,mcast=230.0.0.1:1234,model=virtio-net-pci" from QEMU 
> or macOS itself.
>
> Best regards,
> Vitaly

Would you mind resending the patch with the above as the changelog?

Thanks

>
> > On 31 May 2022, at 10:02, Jason Wang <jasowang@redhat.com> wrote:
> >
> > On Wed, May 18, 2022 at 3:40 PM Vitaly Cheptsov <cheptsov@ispras.ru> wrote:
> >>
> >
> > Hi Vitaly:
> >
> > We need a changelog to describe why we need this.
> >
> > Thanks
> >
> >> Cc: Jason Wang <jasowang@redhat.com>
> >> Cc: Daniel P. Berrange <berrange@redhat.com>
> >> Cc: Philippe Mathieu-Daudé <f4bug@amsat.org>
> >> Signed-off-by: Vitaly Cheptsov <cheptsov@ispras.ru>
> >> ---
> >> net/socket.c | 18 ++++++++++++++++++
> >> 1 file changed, 18 insertions(+)
> >>
> >> diff --git a/net/socket.c b/net/socket.c
> >> index bfd8596250..583f788a22 100644
> >> --- a/net/socket.c
> >> +++ b/net/socket.c
> >> @@ -239,6 +239,22 @@ static int net_socket_mcast_create(struct sockaddr_in 
> >> *mcastaddr,
> >>         return -1;
> >>     }
> >>
> >> +#ifdef __APPLE__
> >> +    val = 1;
> >> +    ret = qemu_setsockopt(fd, SOL_SOCKET, SO_REUSEPORT, &val, 
> >> sizeof(val));
> >> +    if (ret < 0) {
> >> +        error_setg_errno(errp, errno,
> >> +                         "can't set socket option SO_REUSEPORT");
> >> +        goto fail;
> >> +    }
> >> +
> >> +    struct sockaddr_in bindaddr;
> >> +    memset(&bindaddr, 0, sizeof(bindaddr));
> >> +    bindaddr.sin_family = AF_INET;
> >> +    bindaddr.sin_addr.s_addr = htonl(INADDR_ANY);
> >> +    bindaddr.sin_port = mcastaddr->sin_port;
> >> +    ret = bind(fd, (struct sockaddr *)&bindaddr, sizeof(bindaddr));
> >> +#else
> >>     /* Allow multiple sockets to bind the same multicast ip and port by 
> >> setting
> >>      * SO_REUSEADDR. This is the only situation where SO_REUSEADDR should 
> >> be set
> >>      * on windows. Use socket_set_fast_reuse otherwise as it sets 
> >> SO_REUSEADDR
> >> @@ -253,6 +269,8 @@ static int net_socket_mcast_create(struct sockaddr_in 
> >> *mcastaddr,
> >>     }
> >>
> >>     ret = bind(fd, (struct sockaddr *)mcastaddr, sizeof(*mcastaddr));
> >> +#endif
> >> +
> >>     if (ret < 0) {
> >>         error_setg_errno(errp, errno, "can't bind ip=%s to socket",
> >>                          inet_ntoa(mcastaddr->sin_addr));
> >> --
> >> 2.32.1 (Apple Git-133)
> >>
> >
>