8eb517a2a4
Guillaume Nault says: ==================== net: reset MAC header consistently across L3 virtual devices Some virtual L3 devices, like vxlan-gpe and gre (in collect_md mode), reset the MAC header pointer after they parsed the outer headers. This accurately reflects the fact that the decapsulated packet is pure L3 packet, as that makes the MAC header 0 bytes long (the MAC and network header pointers are equal). However, many L3 devices only adjust the network header after decapsulation and leave the MAC header pointer to its original value. This can confuse other parts of the networking stack, like TC, which then considers the outer headers as one big MAC header. This patch series makes the following L3 tunnels behave like VXLAN-GPE: bareudp, ipip, sit, gre, ip6gre, ip6tnl, gtp. The case of gre is a bit special. It already resets the MAC header pointer in collect_md mode, so only the classical mode needs to be adjusted. However, gre also has a special case that expects the MAC header pointer to keep pointing to the outer header even after decapsulation. Therefore, patch 4 keeps an exception for this case. Ideally, we'd centralise the call to skb_reset_mac_header() in ip_tunnel_rcv(), to avoid manual calls in ipip (patch 2), sit (patch 3) and gre (patch 4). That's unfortunately not feasible currently, because of the gre special case discussed above that precludes us from resetting the MAC header unconditionally. The original motivation is to redirect bareudp packets to Ethernet devices (as described in patch 1). The rest of this series aims at bringing consistency across all L3 devices (apart from gre's special case unfortunately). Note: the gtp patch results from pure code inspection and has been compiled tested only. ==================== Signed-off-by: David S. Miller <davem@davemloft.net>
Linux kernel
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