From 6103aa96ec077c976e851e0b89cc2446cb76573d Mon Sep 17 00:00:00 2001 From: John Fastabend Date: Mon, 17 Jul 2017 09:27:50 -0700 Subject: [PATCH] net: implement XDP_REDIRECT for xdp generic Add support for redirect to xdp generic creating a fall back for devices that do not yet have support and allowing test infrastructure using veth pairs to be built. Signed-off-by: John Fastabend Tested-by: Andy Gospodarek Acked-by: Daniel Borkmann Acked-by: Jesper Dangaard Brouer Signed-off-by: David S. Miller --- include/linux/filter.h | 1 + net/core/dev.c | 22 ++++++++++++++++++++-- net/core/filter.c | 26 ++++++++++++++++++++++++++ 3 files changed, 47 insertions(+), 2 deletions(-) diff --git a/include/linux/filter.h b/include/linux/filter.h index 64cae7a08148..10df7daf5ec6 100644 --- a/include/linux/filter.h +++ b/include/linux/filter.h @@ -712,6 +712,7 @@ bool bpf_helper_changes_pkt_data(void *func); struct bpf_prog *bpf_patch_insn_single(struct bpf_prog *prog, u32 off, const struct bpf_insn *patch, u32 len); +int xdp_do_generic_redirect(struct net_device *dev, struct sk_buff *skb); int xdp_do_redirect(struct net_device *dev, struct xdp_buff *xdp); void bpf_warn_invalid_xdp_action(u32 act); diff --git a/net/core/dev.c b/net/core/dev.c index a1ed7b41b3e8..9f3f4083ada5 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -3902,6 +3902,7 @@ static u32 netif_receive_generic_xdp(struct sk_buff *skb, __skb_push(skb, -off); switch (act) { + case XDP_REDIRECT: case XDP_TX: __skb_push(skb, mac_len); /* fall through */ @@ -3956,14 +3957,27 @@ static int do_xdp_generic(struct sk_buff *skb) if (xdp_prog) { u32 act = netif_receive_generic_xdp(skb, xdp_prog); + int err; if (act != XDP_PASS) { - if (act == XDP_TX) + switch (act) { + case XDP_REDIRECT: + err = xdp_do_generic_redirect(skb->dev, skb); + if (err) + goto out_redir; + /* fallthru to submit skb */ + case XDP_TX: generic_xdp_tx(skb, xdp_prog); + break; + } return XDP_DROP; } } return XDP_PASS; +out_redir: + trace_xdp_exception(skb->dev, xdp_prog, XDP_REDIRECT); + kfree_skb(skb); + return XDP_DROP; } static int netif_rx_internal(struct sk_buff *skb) @@ -3977,8 +3991,12 @@ static int netif_rx_internal(struct sk_buff *skb) if (static_key_false(&generic_xdp_needed)) { int ret = do_xdp_generic(skb); + /* Consider XDP consuming the packet a success from + * the netdev point of view we do not want to count + * this as an error. + */ if (ret != XDP_PASS) - return NET_RX_DROP; + return NET_RX_SUCCESS; } #ifdef CONFIG_RPS diff --git a/net/core/filter.c b/net/core/filter.c index d606a66d1040..eeb713461c25 100644 --- a/net/core/filter.c +++ b/net/core/filter.c @@ -2437,6 +2437,32 @@ int xdp_do_redirect(struct net_device *dev, struct xdp_buff *xdp) } EXPORT_SYMBOL_GPL(xdp_do_redirect); +int xdp_do_generic_redirect(struct net_device *dev, struct sk_buff *skb) +{ + struct redirect_info *ri = this_cpu_ptr(&redirect_info); + unsigned int len; + + dev = dev_get_by_index_rcu(dev_net(dev), ri->ifindex); + ri->ifindex = 0; + if (unlikely(!dev)) { + bpf_warn_invalid_xdp_redirect(ri->ifindex); + goto err; + } + + if (unlikely(!(dev->flags & IFF_UP))) + goto err; + + len = dev->mtu + dev->hard_header_len + VLAN_HLEN; + if (skb->len > len) + goto err; + + skb->dev = dev; + return 0; +err: + return -EINVAL; +} +EXPORT_SYMBOL_GPL(xdp_do_generic_redirect); + BPF_CALL_2(bpf_xdp_redirect, u32, ifindex, u64, flags) { struct redirect_info *ri = this_cpu_ptr(&redirect_info);