Re: [Qemu-devel] [PATCH 04/18] slirp: Make Socket structure IPv6 compatible

[Thomas Huth <thuth@redhat.com>]

On 11/12/15 01:15, Samuel Thibault wrote:
> From: Guillaume Subiron <maethor@subiron.org>
> 
> This patch replaces foreign and local address/port couples in Socket
> structure by 2 sockaddr_storage which can be casted in sockaddr_in.
> Direct access to address and port is still possible thanks to some
> \#define, so retrocompatibility of the existing code is assured.
> 
> The ss_family field of sockaddr_storage is declared after each socket
> creation.
> 
> The whole structure is also saved/restored when a Qemu session is
> saved/restored.
> 
> Signed-off-by: Guillaume Subiron <maethor@subiron.org>
> Signed-off-by: Samuel Thibault <samuel.thibault@ens-lyon.org>
> ---
[...]
> diff --git a/slirp/slirp.c b/slirp/slirp.c
> index 66c4196..0937ee0 100644
> --- a/slirp/slirp.c
> +++ b/slirp/slirp.c
> @@ -1028,10 +1028,26 @@ static void slirp_sbuf_save(QEMUFile *f, struct sbuf *sbuf)
>  static void slirp_socket_save(QEMUFile *f, struct socket *so)
>  {
>      qemu_put_be32(f, so->so_urgc);
> -    qemu_put_be32(f, so->so_faddr.s_addr);
> -    qemu_put_be32(f, so->so_laddr.s_addr);
> -    qemu_put_be16(f, so->so_fport);
> -    qemu_put_be16(f, so->so_lport);
> +    qemu_put_be16(f, so->so_ffamily);
> +    switch (so->so_ffamily) {
> +    case AF_INET:
> +        qemu_put_be32(f, so->so_faddr.s_addr);
> +        qemu_put_be16(f, so->so_fport);
> +        break;
> +    default:
> +        fprintf(stderr,
> +                "so_ffamily unknown, unable to save so_faddr and so_fport\n");
> +    }
> +    qemu_put_be16(f, so->so_lfamily);
> +    switch (so->so_lfamily) {
> +    case AF_INET:
> +        qemu_put_be32(f, so->so_laddr.s_addr);
> +        qemu_put_be16(f, so->so_lport);
> +        break;
> +    default:
> +        fprintf(stderr,
> +                "so_ffamily unknown, unable to save so_laddr and so_lport\n");
> +    }
>      qemu_put_byte(f, so->so_iptos);
>      qemu_put_byte(f, so->so_emu);
>      qemu_put_byte(f, so->so_type);
> @@ -1151,10 +1167,26 @@ static int slirp_socket_load(QEMUFile *f, struct socket *so)
>          return -ENOMEM;
>  
>      so->so_urgc = qemu_get_be32(f);
> -    so->so_faddr.s_addr = qemu_get_be32(f);
> -    so->so_laddr.s_addr = qemu_get_be32(f);
> -    so->so_fport = qemu_get_be16(f);
> -    so->so_lport = qemu_get_be16(f);
> +    so->so_ffamily = qemu_get_be16(f);
> +    switch (so->so_ffamily) {
> +    case AF_INET:
> +        so->so_faddr.s_addr = qemu_get_be32(f);
> +        so->so_fport = qemu_get_be16(f);
> +        break;
> +    default:
> +        fprintf(stderr,
> +                "so_ffamily unknown, unable to restore so_faddr and so_lport\n");
> +    }
> +    so->so_lfamily = qemu_get_be16(f);
> +    switch (so->so_lfamily) {
> +    case AF_INET:
> +        so->so_laddr.s_addr = qemu_get_be32(f);
> +        so->so_lport = qemu_get_be16(f);
> +        break;
> +    default:
> +        fprintf(stderr,
> +                "so_ffamily unknown, unable to restore so_laddr and so_lport\n");
> +    }

Since you're changing the layout of the save data here, I think you have
to bump the version_id number in the register_savevm() call in
slirp_init() to make it clear that the new layout is incompatible.

>      so->so_iptos = qemu_get_byte(f);
>      so->so_emu = qemu_get_byte(f);
>      so->so_type = qemu_get_byte(f);
> diff --git a/slirp/socket.c b/slirp/socket.c
> index 1673e3a..bf603c9 100644
> --- a/slirp/socket.c
> +++ b/slirp/socket.c
[...]

Remaining parts of the patch look fine to me.

 Thomas