forked from luck/tmp_suning_uos_patched
xdp: adjust xdp redirect tracepoint to include return error code
The return error code need to be included in the tracepoint xdp:xdp_redirect, else its not possible to distinguish successful or failed XDP_REDIRECT transmits. XDP have no queuing mechanism. Thus, it is fairly easily to overrun a NIC transmit queue. The eBPF program invoking helpers (bpf_redirect or bpf_redirect_map) to redirect a packet doesn't get any feedback whether the packet was actually transmitted. Info on failed transmits in the tracepoint xdp:xdp_redirect, is interesting as this opens for providing a feedback-loop to the receiving XDP program. Signed-off-by: Jesper Dangaard Brouer <brouer@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
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d2cee2e5d0
commit
4c03bdd7b5
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@ -53,15 +53,16 @@ TRACE_EVENT(xdp_redirect,
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TP_PROTO(const struct net_device *from,
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const struct net_device *to,
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const struct bpf_prog *xdp, u32 act),
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const struct bpf_prog *xdp, u32 act, int err),
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TP_ARGS(from, to, xdp, act),
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TP_ARGS(from, to, xdp, act, err),
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TP_STRUCT__entry(
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__string(name_from, from->name)
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__string(name_to, to->name)
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__array(u8, prog_tag, 8)
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__field(u32, act)
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__field(int, err)
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),
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TP_fast_assign(
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@ -70,12 +71,14 @@ TRACE_EVENT(xdp_redirect,
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__assign_str(name_from, from->name);
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__assign_str(name_to, to->name);
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__entry->act = act;
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__entry->err = err;
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),
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TP_printk("prog=%s from=%s to=%s action=%s",
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TP_printk("prog=%s from=%s to=%s action=%s err=%d",
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__print_hex_str(__entry->prog_tag, 8),
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__get_str(name_from), __get_str(name_to),
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__print_symbolic(__entry->act, __XDP_ACT_SYM_TAB))
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__print_symbolic(__entry->act, __XDP_ACT_SYM_TAB),
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__entry->err)
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);
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#endif /* _TRACE_XDP_H */
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@ -2535,14 +2535,16 @@ int xdp_do_redirect_map(struct net_device *dev, struct xdp_buff *xdp,
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struct bpf_map *map = ri->map;
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u32 index = ri->ifindex;
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struct net_device *fwd;
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int err = -EINVAL;
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int err;
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ri->ifindex = 0;
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ri->map = NULL;
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fwd = __dev_map_lookup_elem(map, index);
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if (!fwd)
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if (!fwd) {
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err = -EINVAL;
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goto out;
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}
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if (ri->map_to_flush && (ri->map_to_flush != map))
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xdp_do_flush_map();
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@ -2552,7 +2554,7 @@ int xdp_do_redirect_map(struct net_device *dev, struct xdp_buff *xdp,
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ri->map_to_flush = map;
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out:
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trace_xdp_redirect(dev, fwd, xdp_prog, XDP_REDIRECT);
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trace_xdp_redirect(dev, fwd, xdp_prog, XDP_REDIRECT, err);
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return err;
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}
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@ -2562,6 +2564,7 @@ int xdp_do_redirect(struct net_device *dev, struct xdp_buff *xdp,
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struct redirect_info *ri = this_cpu_ptr(&redirect_info);
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struct net_device *fwd;
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u32 index = ri->ifindex;
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int err;
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if (ri->map)
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return xdp_do_redirect_map(dev, xdp, xdp_prog);
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@ -2570,12 +2573,14 @@ int xdp_do_redirect(struct net_device *dev, struct xdp_buff *xdp,
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ri->ifindex = 0;
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if (unlikely(!fwd)) {
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bpf_warn_invalid_xdp_redirect(index);
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return -EINVAL;
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err = -EINVAL;
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goto out;
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}
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trace_xdp_redirect(dev, fwd, xdp_prog, XDP_REDIRECT);
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return __bpf_tx_xdp(fwd, NULL, xdp, 0);
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err = __bpf_tx_xdp(fwd, NULL, xdp, 0);
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out:
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trace_xdp_redirect(dev, fwd, xdp_prog, XDP_REDIRECT, err);
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return err;
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}
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EXPORT_SYMBOL_GPL(xdp_do_redirect);
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