Merge https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next

Daniel Borkmann says:

====================
bpf-next 2021-08-10

We've added 31 non-merge commits during the last 8 day(s) which contain
a total of 28 files changed, 3644 insertions(+), 519 deletions(-).

1) Native XDP support for bonding driver & related BPF selftests, from Jussi Maki.

2) Large batch of new BPF JIT tests for test_bpf.ko that came out as a result from
   32-bit MIPS JIT development, from Johan Almbladh.

3) Rewrite of netcnt BPF selftest and merge into test_progs, from Stanislav Fomichev.

4) Fix XDP bpf_prog_test_run infra after net to net-next merge, from Andrii Nakryiko.

5) Follow-up fix in unix_bpf_update_proto() to enforce socket type, from Cong Wang.

6) Fix bpf-iter-tcp4 selftest to print the correct dest IP, from Jose Blanquicet.

7) Various misc BPF XDP sample improvements, from Niklas Söderlund, Matthew Cover,
   and Muhammad Falak R Wani.

* https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next: (31 commits)
  bpf, tests: Add tail call test suite
  bpf, tests: Add tests for BPF_CMPXCHG
  bpf, tests: Add tests for atomic operations
  bpf, tests: Add test for 32-bit context pointer argument passing
  bpf, tests: Add branch conversion JIT test
  bpf, tests: Add word-order tests for load/store of double words
  bpf, tests: Add tests for ALU operations implemented with function calls
  bpf, tests: Add more ALU64 BPF_MUL tests
  bpf, tests: Add more BPF_LSH/RSH/ARSH tests for ALU64
  bpf, tests: Add more ALU32 tests for BPF_LSH/RSH/ARSH
  bpf, tests: Add more tests of ALU32 and ALU64 bitwise operations
  bpf, tests: Fix typos in test case descriptions
  bpf, tests: Add BPF_MOV tests for zero and sign extension
  bpf, tests: Add BPF_JMP32 test cases
  samples, bpf: Add an explict comment to handle nested vlan tagging.
  selftests/bpf: Add tests for XDP bonding
  selftests/bpf: Fix xdp_tx.c prog section name
  net, core: Allow netdev_lower_get_next_private_rcu in bh context
  bpf, devmap: Exclude XDP broadcast to master device
  net, bonding: Add XDP support to the bonding driver
  ...
====================

Link: https://lore.kernel.org/r/20210810130038.16927-1-daniel@iogearbox.net
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

2 files changed, 38 insertions, 2 deletions

diff --git a/net/core/dev.c b/net/core/dev.c
index eaaeff404ce9..88650791c360 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -7532,7 +7532,7 @@ void *netdev_lower_get_next_private_rcu(struct net_device *dev,
 {
 	struct netdev_adjacent *lower;
 
-	WARN_ON_ONCE(!rcu_read_lock_held());
+	WARN_ON_ONCE(!rcu_read_lock_held() && !rcu_read_lock_bh_held());
 
 	lower = list_entry_rcu((*iter)->next, struct netdev_adjacent, list);
 
@@ -9297,7 +9297,7 @@ static struct bpf_prog *dev_xdp_prog(struct net_device *dev,
 	return dev->xdp_state[mode].prog;
 }
 
-static u8 dev_xdp_prog_count(struct net_device *dev)
+u8 dev_xdp_prog_count(struct net_device *dev)
 {
 	u8 count = 0;
 	int i;
@@ -9307,6 +9307,7 @@ static u8 dev_xdp_prog_count(struct net_device *dev)
 			count++;
 	return count;
 }
+EXPORT_SYMBOL_GPL(dev_xdp_prog_count);
 
 u32 dev_xdp_prog_id(struct net_device *dev, enum bpf_xdp_mode mode)
 {
@@ -9400,6 +9401,8 @@ static int dev_xdp_attach(struct net_device *dev, struct netlink_ext_ack *extack
 {
 	unsigned int num_modes = hweight32(flags & XDP_FLAGS_MODES);
 	struct bpf_prog *cur_prog;
+	struct net_device *upper;
+	struct list_head *iter;
 	enum bpf_xdp_mode mode;
 	bpf_op_t bpf_op;
 	int err;
@@ -9438,6 +9441,14 @@ static int dev_xdp_attach(struct net_device *dev, struct netlink_ext_ack *extack
 		return -EBUSY;
 	}
 
+	/* don't allow if an upper device already has a program */
+	netdev_for_each_upper_dev_rcu(dev, upper, iter) {
+		if (dev_xdp_prog_count(upper) > 0) {
+			NL_SET_ERR_MSG(extack, "Cannot attach when an upper device already has a program");
+			return -EEXIST;
+		}
+	}
+
 	cur_prog = dev_xdp_prog(dev, mode);
 	/* can't replace attached prog with link */
 	if (link && cur_prog) {
diff --git a/net/core/filter.c b/net/core/filter.c
index 6f493ef5bb14..3aca07c44fad 100644
--- a/net/core/filter.c
+++ b/net/core/filter.c
@@ -3933,6 +3933,31 @@ void bpf_clear_redirect_map(struct bpf_map *map)
 	}
 }
 
+DEFINE_STATIC_KEY_FALSE(bpf_master_redirect_enabled_key);
+EXPORT_SYMBOL_GPL(bpf_master_redirect_enabled_key);
+
+u32 xdp_master_redirect(struct xdp_buff *xdp)
+{
+	struct net_device *master, *slave;
+	struct bpf_redirect_info *ri = this_cpu_ptr(&bpf_redirect_info);
+
+	master = netdev_master_upper_dev_get_rcu(xdp->rxq->dev);
+	slave = master->netdev_ops->ndo_xdp_get_xmit_slave(master, xdp);
+	if (slave && slave != xdp->rxq->dev) {
+		/* The target device is different from the receiving device, so
+		 * redirect it to the new device.
+		 * Using XDP_REDIRECT gets the correct behaviour from XDP enabled
+		 * drivers to unmap the packet from their rx ring.
+		 */
+		ri->tgt_index = slave->ifindex;
+		ri->map_id = INT_MAX;
+		ri->map_type = BPF_MAP_TYPE_UNSPEC;
+		return XDP_REDIRECT;
+	}
+	return XDP_TX;
+}
+EXPORT_SYMBOL_GPL(xdp_master_redirect);
+
 int xdp_do_redirect(struct net_device *dev, struct xdp_buff *xdp,
 		    struct bpf_prog *xdp_prog)
 {