On 06/10/2017 11:30 PM, Donald Sharp wrote:
> This patch fixes two issues:
>
> 1) When forwarding on *,G mroutes that are in a vrf, the
> kernel was dropping information about the actual incoming
> interface when calling ip_mr_forward from ip_mr_input.
> This caused ip_mr_forward to send the multicast packet
> back out the incoming interface. Fix this by
> modifying ip_mr_forward to be handed the correctly
> resolved dev.
>
> 2) When a unresolved cache entry is created we store
> the incoming skb on the unresolved cache entry and
> upon mroute resolution from the user space daemon,
> we attempt to forward the packet. Again we were
> not resolving to the correct incoming device for
> a vrf scenario, before calling ip_mr_forward.
> Fix this by resolving to the correct interface
> and calling ip_mr_forward with the result.
>
> Fixes: e58e41596811 ("net: Enable support for VRF with ipv4 multicast")
> Signed-off-by: Donald Sharp <sha...@cumulusnetworks.com>
> ---
> v2: Fixed title
> v3: Addressed Review comments by Andrew Lunn and David Ahern
>
> net/ipv4/ipmr.c | 32 +++++++++++++++-----------------
> 1 file changed, 15 insertions(+), 17 deletions(-)
>
> diff --git a/net/ipv4/ipmr.c b/net/ipv4/ipmr.c
> index 551de4d..09368a1 100644
> --- a/net/ipv4/ipmr.c
> +++ b/net/ipv4/ipmr.c
> @@ -101,8 +101,8 @@ static struct mr_table *ipmr_new_table(struct net *net,
> u32 id);
> static void ipmr_free_table(struct mr_table *mrt);
>
> static void ip_mr_forward(struct net *net, struct mr_table *mrt,
> - struct sk_buff *skb, struct mfc_cache *cache,
> - int local);
> + struct net_device *dev, struct sk_buff *skb,
> + struct mfc_cache *cache, int local);
> static int ipmr_cache_report(struct mr_table *mrt,
> struct sk_buff *pkt, vifi_t vifi, int assert);
> static int __ipmr_fill_mroute(struct mr_table *mrt, struct sk_buff *skb,
> @@ -988,7 +988,7 @@ static void ipmr_cache_resolve(struct net *net, struct
> mr_table *mrt,
>
> rtnl_unicast(skb, net, NETLINK_CB(skb).portid);
> } else {
> - ip_mr_forward(net, mrt, skb, c, 0);
> + ip_mr_forward(net, mrt, skb->dev, skb, c, 0);
> }
> }
> }
> @@ -1073,7 +1073,7 @@ static int ipmr_cache_report(struct mr_table *mrt,
>
> /* Queue a packet for resolution. It gets locked cache entry! */
> static int ipmr_cache_unresolved(struct mr_table *mrt, vifi_t vifi,
> - struct sk_buff *skb)
> + struct sk_buff *skb, struct net_device *dev)
> {
> const struct iphdr *iph = ip_hdr(skb);
> struct mfc_cache *c;
> @@ -1130,6 +1130,10 @@ static int ipmr_cache_unresolved(struct mr_table *mrt,
> vifi_t vifi,
> kfree_skb(skb);
> err = -ENOBUFS;
> } else {
> + if (dev) {
> + skb->dev = dev;
> + skb->skb_iif = dev->ifindex;
> + }
> skb_queue_tail(&c->mfc_un.unres.unresolved, skb);
> err = 0;
> }
> @@ -1828,10 +1832,10 @@ static int ipmr_find_vif(struct mr_table *mrt, struct
> net_device *dev)
>
> /* "local" means that we should preserve one skb (for local delivery) */
> static void ip_mr_forward(struct net *net, struct mr_table *mrt,
> - struct sk_buff *skb, struct mfc_cache *cache,
> - int local)
> + struct net_device *dev, struct sk_buff *skb,
> + struct mfc_cache *cache, int local)
> {
> - int true_vifi = ipmr_find_vif(mrt, skb->dev);
> + int true_vifi = ipmr_find_vif(mrt, dev);
> int psend = -1;
> int vif, ct;
>
> @@ -1853,13 +1857,7 @@ static void ip_mr_forward(struct net *net, struct
> mr_table *mrt,
> }
>
> /* Wrong interface: drop packet and (maybe) send PIM assert. */
> - if (mrt->vif_table[vif].dev != skb->dev) {
> - struct net_device *mdev;
> -
> - mdev = l3mdev_master_dev_rcu(mrt->vif_table[vif].dev);
> - if (mdev == skb->dev)
> - goto forward;
> -
> + if (mrt->vif_table[vif].dev != dev) {
> if (rt_is_output_route(skb_rtable(skb))) {
> /* It is our own packet, looped back.
> * Very complicated situation...
> @@ -2053,7 +2051,7 @@ int ip_mr_input(struct sk_buff *skb)
> read_lock(&mrt_lock);
> vif = ipmr_find_vif(mrt, dev);
> if (vif >= 0) {
> - int err2 = ipmr_cache_unresolved(mrt, vif, skb);
> + int err2 = ipmr_cache_unresolved(mrt, vif, skb, dev);
> read_unlock(&mrt_lock);
>
> return err2;
> @@ -2064,7 +2062,7 @@ int ip_mr_input(struct sk_buff *skb)
> }
>
> read_lock(&mrt_lock);
> - ip_mr_forward(net, mrt, skb, cache, local);
> + ip_mr_forward(net, mrt, dev, skb, cache, local);
> read_unlock(&mrt_lock);
>
> if (local)
> @@ -2238,7 +2236,7 @@ int ipmr_get_route(struct net *net, struct sk_buff *skb,
> iph->saddr = saddr;
> iph->daddr = daddr;
> iph->version = 0;
> - err = ipmr_cache_unresolved(mrt, vif, skb2);
> + err = ipmr_cache_unresolved(mrt, vif, skb2, dev);
> read_unlock(&mrt_lock);
> rcu_read_unlock();
> return err;
Thanks Donald!
Reviewed-by: Yotam Gigi <yot...@mellanox.com>
