Re: [Qemu-devel] [PATCH v2] slirp: fix ICMP handling on macOS hosts

[Samuel Thibault]

Hello,

address@hidden, le sam. 28 juil. 2018 21:54:26 -0400, a ecrit:
> From: Andrew Oates <address@hidden>
> 
> On Linux, SOCK_DGRAM+IPPROTO_ICMP sockets give only the ICMP packet when
> read from.  On macOS, however, the socket acts like a SOCK_RAW socket
> and includes the IP header as well.
> 
> This change strips the extra IP header from the received packet on macOS
> before sending it to the guest.
> 
> Signed-off-by: Andrew Oates <address@hidden>

Applied to my tree, thanks!

> ---
> v2: check validity of inner_hlen and update len appropriately
> 
>  slirp/ip_icmp.c | 16 +++++++++++++++-
>  1 file changed, 15 insertions(+), 1 deletion(-)
> 
> diff --git a/slirp/ip_icmp.c b/slirp/ip_icmp.c
> index 0b667a429a..76c6d54b11 100644
> --- a/slirp/ip_icmp.c
> +++ b/slirp/ip_icmp.c
> @@ -420,7 +420,21 @@ void icmp_receive(struct socket *so)
>      icp = mtod(m, struct icmp *);
>  
>      id = icp->icmp_id;
> -    len = qemu_recv(so->s, icp, m->m_len, 0);
> +    len = qemu_recv(so->s, icp, M_ROOM(m), 0);
> +#ifdef CONFIG_DARWIN
> +    if (len > 0) {
> +        /* Skip the IP header that OS X (unlike Linux) includes. */
> +        struct ip *inner_ip = mtod(m, struct ip *);
> +        int inner_hlen = inner_ip->ip_hl << 2;
> +        if (inner_hlen > len) {
> +            len = -1;
> +            errno = -EINVAL;
> +        } else {
> +            len -= inner_hlen;
> +            memmove(icp, (unsigned char *)icp + inner_hlen, len);
> +        }
> +    }
> +#endif
>      icp->icmp_id = id;
>  
>      m->m_data -= hlen;
> -- 
> 2.17.0
> 

-- 
Samuel
"...Unix, MS-DOS, and Windows NT (also known as the Good, the Bad, and
the Ugly)."
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