On Wed, 07 Sep 2016 21:52:56 -0700
Eric Dumazet <eric.duma...@gmail.com> wrote:
> From: Eric Dumazet <eduma...@google.com>
>
> In commit f02db315b8d8 ("ipv4: IP_TOS and IP_TTL can be specified as
> ancillary data") Francesco added IP_TOS values specified as integer.
>
> However, kernel sends to userspace (at recvmsg() time) an IP_TOS value
> in a single byte, when IP_RECVTOS is set on the socket.
>
> It can be very useful to reflect all ancillary options as given by the
> kernel in a subsequent sendmsg(), instead of aborting the sendmsg() with
> EINVAL after Francesco patch.
>
> So this patch extends IP_TOS ancillary to accept an u8, so that an UDP
> server can simply reuse same ancillary block without having to mangle
> it.
>
> Jesper can then augment
> https://github.com/netoptimizer/network-testing/blob/master/src/udp_example02.c
> to add TOS reflection ;)
This is actually your old program ;-)
Do I need to change anything, as I'm just bouncing the packet back with
sendmsg() ?
> Fixes: f02db315b8d8 ("ipv4: IP_TOS and IP_TTL can be specified as ancillary
> data")
> Signed-off-by: Eric Dumazet <eduma...@google.com>
> Cc: Francesco Fusco <ffu...@redhat.com>
> Cc: Jesper Dangaard Brouer <bro...@redhat.com>
Looks like a good fix,
Acked-by: Jesper Dangaard Brouer <bro...@redhat.com>
> ---
> net/ipv4/ip_sockglue.c | 7 +++++--
> 1 file changed, 5 insertions(+), 2 deletions(-)
>
> diff --git a/net/ipv4/ip_sockglue.c b/net/ipv4/ip_sockglue.c
> index
> 71a52f4d4cffba2db9353f43dc817689bf4fab10..af4919792b6a812041dcb18ff30aa8b27482c7a2
> 100644
> --- a/net/ipv4/ip_sockglue.c
> +++ b/net/ipv4/ip_sockglue.c
> @@ -284,9 +284,12 @@ int ip_cmsg_send(struct sock *sk, struct msghdr *msg,
> struct ipcm_cookie *ipc,
> ipc->ttl = val;
> break;
> case IP_TOS:
> - if (cmsg->cmsg_len != CMSG_LEN(sizeof(int)))
> + if (cmsg->cmsg_len == CMSG_LEN(sizeof(int)))
> + val = *(int *)CMSG_DATA(cmsg);
> + else if (cmsg->cmsg_len == CMSG_LEN(sizeof(u8)))
> + val = *(u8 *)CMSG_DATA(cmsg);
> + else
> return -EINVAL;
> - val = *(int *)CMSG_DATA(cmsg);
> if (val < 0 || val > 255)
> return -EINVAL;
> ipc->tos = val;
>
>
--
Best regards,
Jesper Dangaard Brouer
MSc.CS, Principal Kernel Engineer at Red Hat
Author of http://www.iptv-analyzer.org
LinkedIn: http://www.linkedin.com/in/brouer
