From 7cda76d858a4e71ac4a04066c093679a12e1312c Mon Sep 17 00:00:00 2001 From: Lorenzo Bianconi Date: Fri, 11 Mar 2022 10:14:20 +0100 Subject: [PATCH] veth: Allow jumbo frames in xdp mode MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Allow increasing the MTU over page boundaries on veth devices if the attached xdp program declares to support xdp fragments. Signed-off-by: Lorenzo Bianconi Signed-off-by: Daniel Borkmann Acked-by: Toke Høiland-Jørgensen Acked-by: John Fastabend Link: https://lore.kernel.org/bpf/d5dc039c3d4123426e7023a488c449181a7bc57f.1646989407.git.lorenzo@kernel.org --- drivers/net/veth.c | 11 ++++++++--- 1 file changed, 8 insertions(+), 3 deletions(-) --- a/drivers/net/veth.c +++ b/drivers/net/veth.c @@ -1470,9 +1470,14 @@ static int veth_xdp_set(struct net_devic goto err; } - max_mtu = PAGE_SIZE - VETH_XDP_HEADROOM - - peer->hard_header_len - - SKB_DATA_ALIGN(sizeof(struct skb_shared_info)); + max_mtu = SKB_WITH_OVERHEAD(PAGE_SIZE - VETH_XDP_HEADROOM) - + peer->hard_header_len; + /* Allow increasing the max_mtu if the program supports + * XDP fragments. + */ + //if (prog->aux->xdp_has_frags) + max_mtu += PAGE_SIZE * MAX_SKB_FRAGS; + if (peer->mtu > max_mtu) { NL_SET_ERR_MSG_MOD(extack, "Peer MTU is too large to set XDP"); err = -ERANGE;