net: Fix netns for ip_tunnel_init_flow()

JIRA: https://issues.redhat.com/browse/RHEL-73391
Upstream Status: linux.git
Conflicts:
  * Missing upstream commit ac931d4 ("ipip,ip_tunnel,sit: Add FOU
    support for externally controlled ipip devices"):
    No "if (!tunnel_hlen)" in ip_md_tunnel_xmit() in RHEL 9.
  * Missing upstream commit e7191e5 ("ipv4: ip_tunnel: Unmask upper
    DSCP bits in ip_tunnel_bind_dev()"):
    RHEL 9 still uses RT_TOS() in ip_tunnel_bind_dev(), instead of just
    masking the ECN bits with INET_DSCP_MASK.
  * Missing upstream commit c34cfe7 ("ipv4: ip_tunnel: Unmask upper
    DSCP bits in ip_md_tunnel_xmit()"):
    RHEL 9 still uses RT_TOS() in ip_md_tunnel_xmit(), instead of just
    masking the ECN bits with INET_DSCP_MASK.
  * Missing upstream commit c2b639f ("ipv4: ip_tunnel: Unmask upper
    DSCP bits in ip_tunnel_xmit()"):
    RHEL 9 still uses RT_TOS() in ip_tunnel_xmit(), instead of just
    masking the ECN bits with INET_DSCP_MASK.

commit b5a7b66
Author: Xiao Liang <shaw.leon@gmail.com>
Date:   Thu Dec 19 21:03:36 2024 +0800

    net: Fix netns for ip_tunnel_init_flow()

    The device denoted by tunnel->parms.link resides in the underlay net
    namespace. Therefore pass tunnel->net to ip_tunnel_init_flow().

    Fixes: db53cd3 ("net: Handle l3mdev in ip_tunnel_init_flow")
    Signed-off-by: Xiao Liang <shaw.leon@gmail.com>
    Reviewed-by: Ido Schimmel <idosch@nvidia.com>
    Link: https://patch.msgid.link/20241219130336.103839-1-shaw.leon@gmail.com
    Signed-off-by: Jakub Kicinski <kuba@kernel.org>

Signed-off-by: Guillaume Nault <gnault@redhat.com>

Author: Guillaume Nault

drivers/net/ethernet/mellanox/mlxsw/spectrum_span.c

@@ -423,8 +423,7 @@ mlxsw_sp_span_gretap4_route(const struct net_device *to_dev,
 
 	parms = mlxsw_sp_ipip_netdev_parms4(to_dev);
 	ip_tunnel_init_flow(&fl4, parms.iph.protocol, *daddrp, *saddrp,
-			    0, 0, dev_net(to_dev), parms.link, tun->fwmark, 0,
-			    0);
+			    0, 0, tun->net, parms.link, tun->fwmark, 0, 0);
 
 	rt = ip_route_output_key(tun->net, &fl4);
 	if (IS_ERR(rt))

net/ipv4/ip_tunnel.c

@@ -293,7 +293,7 @@ static int ip_tunnel_bind_dev(struct net_device *dev)
 
 		ip_tunnel_init_flow(&fl4, iph->protocol, iph->daddr,
 				    iph->saddr, tunnel->parms.o_key,
-				    RT_TOS(iph->tos), dev_net(dev),
+				    RT_TOS(iph->tos), tunnel->net,
 				    tunnel->parms.link, tunnel->fwmark, 0, 0);
 		rt = ip_route_output_key(tunnel->net, &fl4);
 
@@ -596,7 +596,7 @@ void ip_md_tunnel_xmit(struct sk_buff *skb, struct net_device *dev,
 	}
 	ip_tunnel_init_flow(&fl4, proto, key->u.ipv4.dst, key->u.ipv4.src,
 			    tunnel_id_to_key32(key->tun_id), RT_TOS(tos),
-			    dev_net(dev), 0, skb->mark, skb_get_hash(skb),
+			    tunnel->net, 0, skb->mark, skb_get_hash(skb),
 			    key->flow_flags);
 	if (tunnel->encap.type != TUNNEL_ENCAP_NONE)
 		goto tx_error;
@@ -755,7 +755,7 @@ void ip_tunnel_xmit(struct sk_buff *skb, struct net_device *dev,
 
 	ip_tunnel_init_flow(&fl4, protocol, dst, tnl_params->saddr,
 			    tunnel->parms.o_key, RT_TOS(tos),
-			    dev_net(dev), READ_ONCE(tunnel->parms.link),
+			    tunnel->net, READ_ONCE(tunnel->parms.link),
 			    tunnel->fwmark, skb_get_hash(skb), 0);
 
 	if (ip_tunnel_encap(skb, tunnel, &protocol, &fl4) < 0)