From 8301c7e012109dd14fbbe52da73c75f131a2e46d Mon Sep 17 00:00:00 2001
From: Abhishek Vijeev <abhishek.vijeev@gmail.com>
Date: Sat, 12 Sep 2020 17:40:37 +0530
Subject: [PATCH] criu: adding support for BPF map name, ifindex and freeze

This commit achieves the following:
a) C/R of a BPF map's name as well as ifindex (index of the network
interface to which the map is attached). This information is not
available from procfs and therefore has to be obtained using the
bpf() system call with BPF_OBJ_GET_INFO_BY_FD.
b) Adds support for frozen maps - during the restore operation, CRIU
now freezes a BPF map that was frozen during checkpoint.

Source files modified:

* bpfmap.c

Signed-off-by: Abhishek Vijeev <abhishek.vijeev@gmail.com>
---
 criu/bpfmap.c | 34 ++++++++++++++++++++++++++++++++--
 1 file changed, 32 insertions(+), 2 deletions(-)

diff --git a/criu/bpfmap.c b/criu/bpfmap.c
index dc8edb09c..dfa0ab96f 100644
--- a/criu/bpfmap.c
+++ b/criu/bpfmap.c
@@ -230,11 +230,19 @@ static int dump_one_bpfmap(int lfd, u32 id, const struct fd_parms *p)
 {
 	BpfmapFileEntry bpf = BPFMAP_FILE_ENTRY__INIT;
 	FileEntry fe = FILE_ENTRY__INIT;
+	struct bpf_map_info map_info;
+	uint32_t info_len = sizeof(struct bpf_map_info);
 	int ret;
 
 	if (parse_fdinfo(lfd, FD_TYPES__BPFMAP, &bpf))
 		return -1;
 
+	ret = bpf_obj_get_info_by_fd(lfd, &map_info, &info_len);
+	if (ret) {
+		pr_perror("Could not get BPF map info");
+		return -1;
+	}
+
 	switch (bpf.map_type) {
 
 		case BPF_MAP_TYPE_HASH:
@@ -242,6 +250,8 @@ static int dump_one_bpfmap(int lfd, u32 id, const struct fd_parms *p)
 			bpf.id = id;
 			bpf.flags = p->flags;
 			bpf.fown = (FownEntry *)&p->fown;
+			bpf.map_name = xstrdup(map_info.name);
+			bpf.ifindex = map_info.ifindex;
 
 			fe.type = FD_TYPES__BPFMAP;
 			fe.id = bpf.id;
@@ -272,14 +282,27 @@ static int bpfmap_open(struct file_desc *d, int *new_fd)
 {
 	struct bpfmap_file_info *info;
 	BpfmapFileEntry *bpfe;
+	struct bpf_create_map_attr xattr;
 	int bpfmap_fd;
 
 	info = container_of(d, struct bpfmap_file_info, d);
 	bpfe = info->bpfe;
 
+	xattr.name = xstrdup(bpfe->map_name);
+	xattr.map_type = bpfe->map_type;
+	xattr.map_flags = bpfe->map_flags;
+	xattr.key_size = bpfe->key_size;
+	xattr.value_size = bpfe->value_size;
+	xattr.max_entries = bpfe->max_entries;
+	xattr.numa_node = 0;
+	xattr.btf_fd = 0;
+	xattr.btf_key_type_id = 0;
+	xattr.btf_value_type_id = 0;
+	xattr.map_ifindex = bpfe->ifindex;
+	xattr.inner_map_fd = 0;
+
 	pr_info_bpfmap("Creating and opening ", bpfe);
-	bpfmap_fd = bpf_create_map(bpfe->map_type, bpfe->key_size,
-						bpfe->value_size, bpfe->max_entries, bpfe->map_flags);
+	bpfmap_fd = bpf_create_map_xattr(&xattr);
 	if (bpfmap_fd < 0) {
 		pr_perror("Can't create bpfmap %#08x", bpfe->id);
 		return -1;
@@ -288,6 +311,13 @@ static int bpfmap_open(struct file_desc *d, int *new_fd)
 	if (restore_bpfmap_data(bpfmap_fd, bpfe->map_id, bpfmap_data_hash_table))
 		return -1;
 
+	if (bpfe->frozen) {
+		if (bpf_map_freeze(bpfmap_fd)) {
+			pr_perror("Can't freeze bpfmap %#08x", bpfe->id);
+			goto err_close;
+		}
+	}
+
 	if (rst_file_params(bpfmap_fd, bpfe->fown, bpfe->flags)) {
 		pr_perror("Can't restore params on bpfmap %#08x", bpfe->id);
 		goto err_close;