Merge branch 'bpf-offload-report-dev'

Jakub Kicinski says:

====================
This series is a redo of reporting offload device information to
user space after the first attempt did not take into account name
spaces.  As requested by Kirill offloads are now protected by an
r/w sem.  This allows us to remove the workqueue and free the
offload state fully when device is removed (suggested by Alexei).

Net namespace is reported with a device/inode pair.

The accompanying bpftool support is placed in common code because
maps will have very similar info.  Note that the UAPI information
can't be nicely encapsulated into a struct, because in case we
need to grow the device information the new fields will have to
be added at the end of struct bpf_prog_info, we can't grow
structures in the middle of bpf_prog_info.

v3:
 - use dev_get_by_index();
 - redo ns code (new patch 6).
v2:
 - rework the locking in patch 1 (use RCU instead of locking
   dependencies);
 - grab RTNL for a short time in patch 6;
 - minor update to the test in patch 8.
====================

Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>

3 files changed, 57 insertions, 0 deletions

diff --git a/tools/bpf/bpftool/common.c b/tools/bpf/bpftool/common.c
index b62c94e3997a..6601c95a9258 100644
--- a/tools/bpf/bpftool/common.c
+++ b/tools/bpf/bpftool/common.c
@@ -44,7 +44,9 @@
 #include <unistd.h>
 #include <linux/limits.h>
 #include <linux/magic.h>
+#include <net/if.h>
 #include <sys/mount.h>
+#include <sys/stat.h>
 #include <sys/types.h>
 #include <sys/vfs.h>
 
@@ -412,3 +414,53 @@ void delete_pinned_obj_table(struct pinned_obj_table *tab)
 		free(obj);
 	}
 }
+
+static char *
+ifindex_to_name_ns(__u32 ifindex, __u32 ns_dev, __u32 ns_ino, char *buf)
+{
+	struct stat st;
+	int err;
+
+	err = stat("/proc/self/ns/net", &st);
+	if (err) {
+		p_err("Can't stat /proc/self: %s", strerror(errno));
+		return NULL;
+	}
+
+	if (st.st_dev != ns_dev || st.st_ino != ns_ino)
+		return NULL;
+
+	return if_indextoname(ifindex, buf);
+}
+
+void print_dev_plain(__u32 ifindex, __u64 ns_dev, __u64 ns_inode)
+{
+	char name[IF_NAMESIZE];
+
+	if (!ifindex)
+		return;
+
+	printf(" dev ");
+	if (ifindex_to_name_ns(ifindex, ns_dev, ns_inode, name))
+		printf("%s", name);
+	else
+		printf("ifindex %u ns_dev %llu ns_ino %llu",
+		       ifindex, ns_dev, ns_inode);
+}
+
+void print_dev_json(__u32 ifindex, __u64 ns_dev, __u64 ns_inode)
+{
+	char name[IF_NAMESIZE];
+
+	if (!ifindex)
+		return;
+
+	jsonw_name(json_wtr, "dev");
+	jsonw_start_object(json_wtr);
+	jsonw_uint_field(json_wtr, "ifindex", ifindex);
+	jsonw_uint_field(json_wtr, "ns_dev", ns_dev);
+	jsonw_uint_field(json_wtr, "ns_inode", ns_inode);
+	if (ifindex_to_name_ns(ifindex, ns_dev, ns_inode, name))
+		jsonw_string_field(json_wtr, "ifname", name);
+	jsonw_end_object(json_wtr);
+}
diff --git a/tools/bpf/bpftool/main.h b/tools/bpf/bpftool/main.h
index 8f6d3cac0347..65b526fe6e7e 100644
--- a/tools/bpf/bpftool/main.h
+++ b/tools/bpf/bpftool/main.h
@@ -96,6 +96,8 @@ struct pinned_obj {
 int build_pinned_obj_table(struct pinned_obj_table *table,
 			   enum bpf_obj_type type);
 void delete_pinned_obj_table(struct pinned_obj_table *tab);
+void print_dev_plain(__u32 ifindex, __u64 ns_dev, __u64 ns_inode);
+void print_dev_json(__u32 ifindex, __u64 ns_dev, __u64 ns_inode);
 
 struct cmd {
 	const char *cmd;
diff --git a/tools/bpf/bpftool/prog.c b/tools/bpf/bpftool/prog.c
index fd0873178503..98f871ed53d6 100644
--- a/tools/bpf/bpftool/prog.c
+++ b/tools/bpf/bpftool/prog.c
@@ -230,6 +230,8 @@ static void print_prog_json(struct bpf_prog_info *info, int fd)
 		     info->tag[0], info->tag[1], info->tag[2], info->tag[3],
 		     info->tag[4], info->tag[5], info->tag[6], info->tag[7]);
 
+	print_dev_json(info->ifindex, info->netns_dev, info->netns_ino);
+
 	if (info->load_time) {
 		char buf[32];
 
@@ -287,6 +289,7 @@ static void print_prog_plain(struct bpf_prog_info *info, int fd)
 
 	printf("tag ");
 	fprint_hex(stdout, info->tag, BPF_TAG_SIZE, "");
+	print_dev_plain(info->ifindex, info->netns_dev, info->netns_ino);
 	printf("\n");
 
 	if (info->load_time) {