[PATCH bpf-next 2/6] bpf: Add syscall common attrs support for xdp link_create

[Leon Hwang <leon.hwang@linux.dev>]

With the syscall common attrs support for link_create, add syscall common
attrs support for xdp link_create in order to report the invalid target
ifindex error and the underlying driver's error.

Signed-off-by: Leon Hwang <leon.hwang@linux.dev>
---
 include/linux/netdevice.h | 3 ++-
 kernel/bpf/syscall.c      | 2 +-
 net/core/dev.c            | 6 +++++-
 3 files changed, 8 insertions(+), 3 deletions(-)

diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index 3cff2174dc03..4548b0fd824d 100644
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -4417,7 +4417,8 @@ struct sk_buff *validate_xmit_skb_list(struct sk_buff *skb, struct net_device *d
 struct sk_buff *dev_hard_start_xmit(struct sk_buff *skb, struct net_device *dev,
 				    struct netdev_queue *txq, int *ret);
 
-int bpf_xdp_link_attach(const union bpf_attr *attr, struct bpf_prog *prog);
+int bpf_xdp_link_attach(const union bpf_attr *attr, struct bpf_prog *prog,
+			struct bpf_verifier_log *log);
 u8 dev_xdp_prog_count(struct net_device *dev);
 int netif_xdp_propagate(struct net_device *dev, struct netdev_bpf *bpf);
 int dev_xdp_propagate(struct net_device *dev, struct netdev_bpf *bpf);
diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c
index 252b479937a4..e96d5f09486f 100644
--- a/kernel/bpf/syscall.c
+++ b/kernel/bpf/syscall.c
@@ -5921,7 +5921,7 @@ static int link_create(union bpf_attr *attr, bpfptr_t uattr, struct bpf_common_a
 		break;
 #ifdef CONFIG_NET
 	case BPF_PROG_TYPE_XDP:
-		ret = bpf_xdp_link_attach(attr, prog);
+		ret = bpf_xdp_link_attach(attr, prog, log);
 		break;
 	case BPF_PROG_TYPE_SCHED_CLS:
 		if (attr->link_create.attach_type == BPF_TCX_INGRESS ||
diff --git a/net/core/dev.c b/net/core/dev.c
index 18dc88990510..fdc1de21f358 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -97,6 +97,7 @@
 #include <linux/kthread.h>
 #include <linux/bpf.h>
 #include <linux/bpf_trace.h>
+#include <linux/bpf_verifier.h>
 #include <net/net_namespace.h>
 #include <net/sock.h>
 #include <net/busy_poll.h>
@@ -10771,7 +10772,8 @@ static const struct bpf_link_ops bpf_xdp_link_lops = {
 	.update_prog = bpf_xdp_link_update,
 };
 
-int bpf_xdp_link_attach(const union bpf_attr *attr, struct bpf_prog *prog)
+int bpf_xdp_link_attach(const union bpf_attr *attr, struct bpf_prog *prog,
+			struct bpf_verifier_log *log)
 {
 	struct net *net = current->nsproxy->net_ns;
 	struct bpf_link_primer link_primer;
@@ -10784,6 +10786,7 @@ int bpf_xdp_link_attach(const union bpf_attr *attr, struct bpf_prog *prog)
 	dev = dev_get_by_index(net, attr->link_create.target_ifindex);
 	if (!dev) {
 		rtnl_unlock();
+		bpf_log(log, "Invalid target_ifindex.\n");
 		return -EINVAL;
 	}
 
@@ -10812,6 +10815,7 @@ int bpf_xdp_link_attach(const union bpf_attr *attr, struct bpf_prog *prog)
 	if (err) {
 		link->dev = NULL;
 		bpf_link_cleanup(&link_primer);
+		bpf_log(log, extack._msg);
 		trace_bpf_xdp_link_attach_failed(extack._msg);
 		goto out_put_dev;
 	}
-- 
2.55.0