Hello,
On Wed, 4 May 2016, David Ahern wrote:
> Applications such as OSPF and BFD need the original ingress device not
> the VRF device; the latter can be derived from the former. To that end
> add the skb_iif to inet_skb_parm and set it in ipv4 code after clearing
> the skb control buffer similar to IPv6. From there the pktinfo can just
> pull it from cb with the PKTINFO_SKB_CB cast.
>
> The previous patch moving the skb->dev change to L3 means nothing else
> is needed for IPv6; it just works.
>
> Signed-off-by: David Ahern <d...@cumulusnetworks.com>
> ---
> include/net/ip.h | 1 +
> net/ipv4/ip_input.c | 1 +
> net/ipv4/ip_sockglue.c | 9 +++++++--
> 3 files changed, 9 insertions(+), 2 deletions(-)
>
> diff --git a/include/net/ip.h b/include/net/ip.h
> index 247ac82e9cf2..37165fba3741 100644
> --- a/include/net/ip.h
> +++ b/include/net/ip.h
> @@ -36,6 +36,7 @@
> struct sock;
>
> struct inet_skb_parm {
> + int iif;
> struct ip_options opt; /* Compiled IP options
> */
> unsigned char flags;
>
> diff --git a/net/ipv4/ip_input.c b/net/ipv4/ip_input.c
> index 37375eedeef9..4b351af3e67b 100644
> --- a/net/ipv4/ip_input.c
> +++ b/net/ipv4/ip_input.c
> @@ -478,6 +478,7 @@ int ip_rcv(struct sk_buff *skb, struct net_device *dev,
> struct packet_type *pt,
>
> /* Remove any debris in the socket control block */
> memset(IPCB(skb), 0, sizeof(struct inet_skb_parm));
> + IPCB(skb)->iif = skb->skb_iif;
For loopback traffic (including looped back multicast)
this is now a zero :( Can inet_iif be moved to ip_rcv_finish
instead? Still, we spend cycles in fast path in case nobody
listens for such info.
> /* Must drop socket now because of tproxy. */
> skb_orphan(skb);
> diff --git a/net/ipv4/ip_sockglue.c b/net/ipv4/ip_sockglue.c
> index bdb222c0c6a2..dbcd027c38e7 100644
> --- a/net/ipv4/ip_sockglue.c
> +++ b/net/ipv4/ip_sockglue.c
> @@ -476,9 +476,9 @@ static bool ipv4_datagram_support_cmsg(const struct sock
> *sk,
> (!skb->dev))
> return false;
>
> + /* see comment in ipv4_pktinfo_prepare about CB re-use */
> info = PKTINFO_SKB_CB(skb);
> info->ipi_spec_dst.s_addr = ip_hdr(skb)->saddr;
> - info->ipi_ifindex = skb->dev->ifindex;
This code is only for SOF_TIMESTAMPING_OPT_CMSG.
I'm not sure skb passes ip_rcv in all cases. So, we can not
easily remove it.
Regards
--
Julian Anastasov <j...@ssi.bg>
