On 5/5/16 2:41 AM, Julian Anastasov wrote:
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.
Why is that? skb_iif is set to skb->dev->index in __netif_receive_skb_core and ip_rcv is called it. Is there another path to it?
/* 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.
ok.
