xdp: add trace event for xdp redirect

This adds a trace event for xdp redirect which may help when debugging
XDP programs that use redirect bpf commands.

Signed-off-by: John Fastabend <john.fastabend@gmail.com>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Jesper Dangaard Brouer <brouer@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c b/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c
index 3db04736a048e98894f121dbaba941b570fe1f47..38f7ff97d636057f9b2cc50c684c6d916c0020c9 100644 (file)
--- a/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c
+++ b/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c
@@ -2232,7 +2232,7 @@ static struct sk_buff *ixgbe_run_xdp(struct ixgbe_adapter *adapter,
                result = ixgbe_xmit_xdp_ring(adapter, xdp);
                break;
        case XDP_REDIRECT:
-               err = xdp_do_redirect(adapter->netdev, xdp);
+               err = xdp_do_redirect(adapter->netdev, xdp, xdp_prog);
                if (!err)
                        result = IXGBE_XDP_TX;
                else

diff --git a/include/linux/filter.h b/include/linux/filter.h
index 10df7daf5ec6b3c1fa4ea5db5f9f2a8535207e24..ce8211fa91c7e08664b357b4d15441e2792b8a67 100644 (file)
--- a/include/linux/filter.h
+++ b/include/linux/filter.h
@@ -713,7 +713,9 @@ 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);
+int xdp_do_redirect(struct net_device *dev,
+                   struct xdp_buff *xdp,
+                   struct bpf_prog *prog);
 
 void bpf_warn_invalid_xdp_action(u32 act);
 void bpf_warn_invalid_xdp_redirect(u32 ifindex);

diff --git a/include/trace/events/xdp.h b/include/trace/events/xdp.h
index 1b61357d3f575ab8b3c5debd487714cb1430b2b5..7b1eb7b4be41757df036a0190a3eb72ae1187c01 100644 (file)
--- a/include/trace/events/xdp.h
+++ b/include/trace/events/xdp.h
@@ -12,7 +12,8 @@
        FN(ABORTED)             \
        FN(DROP)                \
        FN(PASS)                \
-       FN(TX)
+       FN(TX)                  \
+       FN(REDIRECT)
 
 #define __XDP_ACT_TP_FN(x)     \
        TRACE_DEFINE_ENUM(XDP_##x);
@@ -48,6 +49,34 @@ TRACE_EVENT(xdp_exception,
                  __print_symbolic(__entry->act, __XDP_ACT_SYM_TAB))
 );
 
+TRACE_EVENT(xdp_redirect,
+
+       TP_PROTO(const struct net_device *from,
+                const struct net_device *to,
+                const struct bpf_prog *xdp, u32 act),
+
+       TP_ARGS(from, to, xdp, act),
+
+       TP_STRUCT__entry(
+               __string(name_from, from->name)
+               __string(name_to, to->name)
+               __array(u8, prog_tag, 8)
+               __field(u32, act)
+       ),
+
+       TP_fast_assign(
+               BUILD_BUG_ON(sizeof(__entry->prog_tag) != sizeof(xdp->tag));
+               memcpy(__entry->prog_tag, xdp->tag, sizeof(xdp->tag));
+               __assign_str(name_from, from->name);
+               __assign_str(name_to, to->name);
+               __entry->act = act;
+       ),
+
+       TP_printk("prog=%s from=%s to=%s action=%s",
+                 __print_hex_str(__entry->prog_tag, 8),
+                 __get_str(name_from), __get_str(name_to),
+                 __print_symbolic(__entry->act, __XDP_ACT_SYM_TAB))
+);
 #endif /* _TRACE_XDP_H */
 
 #include <trace/define_trace.h>

diff --git a/net/core/filter.c b/net/core/filter.c
index eeb713461c25e5f5b89b785cec333e3f224999e4..e30d38b27f21738bad2f2c7171eae1c25924c60c 100644 (file)
--- a/net/core/filter.c
+++ b/net/core/filter.c
@@ -55,6 +55,7 @@
 #include <net/sock_reuseport.h>
 #include <net/busy_poll.h>
 #include <net/tcp.h>
+#include <linux/bpf_trace.h>
 
 /**
  *     sk_filter_trim_cap - run a packet through a socket filter
@@ -2422,18 +2423,22 @@ static int __bpf_tx_xdp(struct net_device *dev, struct xdp_buff *xdp)
        return -EOPNOTSUPP;
 }
 
-int xdp_do_redirect(struct net_device *dev, struct xdp_buff *xdp)
+int xdp_do_redirect(struct net_device *dev, struct xdp_buff *xdp,
+                   struct bpf_prog *xdp_prog)
 {
        struct redirect_info *ri = this_cpu_ptr(&redirect_info);
+       struct net_device *fwd;
 
-       dev = dev_get_by_index_rcu(dev_net(dev), ri->ifindex);
+       fwd = dev_get_by_index_rcu(dev_net(dev), ri->ifindex);
        ri->ifindex = 0;
-       if (unlikely(!dev)) {
+       if (unlikely(!fwd)) {
                bpf_warn_invalid_xdp_redirect(ri->ifindex);
                return -EINVAL;
        }
 
-       return __bpf_tx_xdp(dev, xdp);
+       trace_xdp_redirect(dev, fwd, xdp_prog, XDP_REDIRECT);
+
+       return __bpf_tx_xdp(fwd, xdp);
 }
 EXPORT_SYMBOL_GPL(xdp_do_redirect);