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-rw-r--r--include/linux/netdevice.h2
-rw-r--r--include/uapi/linux/if_link.h4
-rw-r--r--net/core/dev.c26
-rw-r--r--net/core/rtnetlink.c14
-rw-r--r--tools/include/uapi/linux/if_link.h4
-rw-r--r--tools/lib/bpf/libbpf.h8
-rw-r--r--tools/lib/bpf/libbpf.map1
-rw-r--r--tools/lib/bpf/netlink.c34
-rw-r--r--tools/testing/selftests/bpf/prog_tests/xdp_attach.c62
9 files changed, 146 insertions, 9 deletions
diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index 654808bfad83..b503d468f0df 100644
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -3768,7 +3768,7 @@ struct sk_buff *dev_hard_start_xmit(struct sk_buff *skb, struct net_device *dev,
typedef int (*bpf_op_t)(struct net_device *dev, struct netdev_bpf *bpf);
int dev_change_xdp_fd(struct net_device *dev, struct netlink_ext_ack *extack,
- int fd, u32 flags);
+ int fd, int expected_fd, u32 flags);
u32 __dev_xdp_query(struct net_device *dev, bpf_op_t xdp_op,
enum bpf_netdev_command cmd);
int xdp_umem_query(struct net_device *dev, u16 queue_id);
diff --git a/include/uapi/linux/if_link.h b/include/uapi/linux/if_link.h
index 61e0801c82df..c2f768c8d65b 100644
--- a/include/uapi/linux/if_link.h
+++ b/include/uapi/linux/if_link.h
@@ -972,11 +972,12 @@ enum {
#define XDP_FLAGS_SKB_MODE (1U << 1)
#define XDP_FLAGS_DRV_MODE (1U << 2)
#define XDP_FLAGS_HW_MODE (1U << 3)
+#define XDP_FLAGS_REPLACE (1U << 4)
#define XDP_FLAGS_MODES (XDP_FLAGS_SKB_MODE | \
XDP_FLAGS_DRV_MODE | \
XDP_FLAGS_HW_MODE)
#define XDP_FLAGS_MASK (XDP_FLAGS_UPDATE_IF_NOEXIST | \
- XDP_FLAGS_MODES)
+ XDP_FLAGS_MODES | XDP_FLAGS_REPLACE)
/* These are stored into IFLA_XDP_ATTACHED on dump. */
enum {
@@ -996,6 +997,7 @@ enum {
IFLA_XDP_DRV_PROG_ID,
IFLA_XDP_SKB_PROG_ID,
IFLA_XDP_HW_PROG_ID,
+ IFLA_XDP_EXPECTED_FD,
__IFLA_XDP_MAX,
};
diff --git a/net/core/dev.c b/net/core/dev.c
index d84541c24446..651a3c28d33a 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -8655,15 +8655,17 @@ static void dev_xdp_uninstall(struct net_device *dev)
* @dev: device
* @extack: netlink extended ack
* @fd: new program fd or negative value to clear
+ * @expected_fd: old program fd that userspace expects to replace or clear
* @flags: xdp-related flags
*
* Set or clear a bpf program for a device
*/
int dev_change_xdp_fd(struct net_device *dev, struct netlink_ext_ack *extack,
- int fd, u32 flags)
+ int fd, int expected_fd, u32 flags)
{
const struct net_device_ops *ops = dev->netdev_ops;
enum bpf_netdev_command query;
+ u32 prog_id, expected_id = 0;
struct bpf_prog *prog = NULL;
bpf_op_t bpf_op, bpf_chk;
bool offload;
@@ -8684,15 +8686,29 @@ int dev_change_xdp_fd(struct net_device *dev, struct netlink_ext_ack *extack,
if (bpf_op == bpf_chk)
bpf_chk = generic_xdp_install;
- if (fd >= 0) {
- u32 prog_id;
+ prog_id = __dev_xdp_query(dev, bpf_op, query);
+ if (flags & XDP_FLAGS_REPLACE) {
+ if (expected_fd >= 0) {
+ prog = bpf_prog_get_type_dev(expected_fd,
+ BPF_PROG_TYPE_XDP,
+ bpf_op == ops->ndo_bpf);
+ if (IS_ERR(prog))
+ return PTR_ERR(prog);
+ expected_id = prog->aux->id;
+ bpf_prog_put(prog);
+ }
+ if (prog_id != expected_id) {
+ NL_SET_ERR_MSG(extack, "Active program does not match expected");
+ return -EEXIST;
+ }
+ }
+ if (fd >= 0) {
if (!offload && __dev_xdp_query(dev, bpf_chk, XDP_QUERY_PROG)) {
NL_SET_ERR_MSG(extack, "native and generic XDP can't be active at the same time");
return -EEXIST;
}
- prog_id = __dev_xdp_query(dev, bpf_op, query);
if ((flags & XDP_FLAGS_UPDATE_IF_NOEXIST) && prog_id) {
NL_SET_ERR_MSG(extack, "XDP program already attached");
return -EBUSY;
@@ -8715,7 +8731,7 @@ int dev_change_xdp_fd(struct net_device *dev, struct netlink_ext_ack *extack,
return 0;
}
} else {
- if (!__dev_xdp_query(dev, bpf_op, query))
+ if (!prog_id)
return 0;
}
diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c
index 14e6ea21c378..709ebbf8ab5b 100644
--- a/net/core/rtnetlink.c
+++ b/net/core/rtnetlink.c
@@ -1872,7 +1872,9 @@ static const struct nla_policy ifla_port_policy[IFLA_PORT_MAX+1] = {
};
static const struct nla_policy ifla_xdp_policy[IFLA_XDP_MAX + 1] = {
+ [IFLA_XDP_UNSPEC] = { .strict_start_type = IFLA_XDP_EXPECTED_FD },
[IFLA_XDP_FD] = { .type = NLA_S32 },
+ [IFLA_XDP_EXPECTED_FD] = { .type = NLA_S32 },
[IFLA_XDP_ATTACHED] = { .type = NLA_U8 },
[IFLA_XDP_FLAGS] = { .type = NLA_U32 },
[IFLA_XDP_PROG_ID] = { .type = NLA_U32 },
@@ -2799,8 +2801,20 @@ static int do_setlink(const struct sk_buff *skb,
}
if (xdp[IFLA_XDP_FD]) {
+ int expected_fd = -1;
+
+ if (xdp_flags & XDP_FLAGS_REPLACE) {
+ if (!xdp[IFLA_XDP_EXPECTED_FD]) {
+ err = -EINVAL;
+ goto errout;
+ }
+ expected_fd =
+ nla_get_s32(xdp[IFLA_XDP_EXPECTED_FD]);
+ }
+
err = dev_change_xdp_fd(dev, extack,
nla_get_s32(xdp[IFLA_XDP_FD]),
+ expected_fd,
xdp_flags);
if (err)
goto errout;
diff --git a/tools/include/uapi/linux/if_link.h b/tools/include/uapi/linux/if_link.h
index 024af2d1d0af..b1ec7c949e6a 100644
--- a/tools/include/uapi/linux/if_link.h
+++ b/tools/include/uapi/linux/if_link.h
@@ -960,11 +960,12 @@ enum {
#define XDP_FLAGS_SKB_MODE (1U << 1)
#define XDP_FLAGS_DRV_MODE (1U << 2)
#define XDP_FLAGS_HW_MODE (1U << 3)
+#define XDP_FLAGS_REPLACE (1U << 4)
#define XDP_FLAGS_MODES (XDP_FLAGS_SKB_MODE | \
XDP_FLAGS_DRV_MODE | \
XDP_FLAGS_HW_MODE)
#define XDP_FLAGS_MASK (XDP_FLAGS_UPDATE_IF_NOEXIST | \
- XDP_FLAGS_MODES)
+ XDP_FLAGS_MODES | XDP_FLAGS_REPLACE)
/* These are stored into IFLA_XDP_ATTACHED on dump. */
enum {
@@ -984,6 +985,7 @@ enum {
IFLA_XDP_DRV_PROG_ID,
IFLA_XDP_SKB_PROG_ID,
IFLA_XDP_HW_PROG_ID,
+ IFLA_XDP_EXPECTED_FD,
__IFLA_XDP_MAX,
};
diff --git a/tools/lib/bpf/libbpf.h b/tools/lib/bpf/libbpf.h
index d38d7a629417..bf7a35a9556d 100644
--- a/tools/lib/bpf/libbpf.h
+++ b/tools/lib/bpf/libbpf.h
@@ -444,7 +444,15 @@ struct xdp_link_info {
__u8 attach_mode;
};
+struct bpf_xdp_set_link_opts {
+ size_t sz;
+ __u32 old_fd;
+};
+#define bpf_xdp_set_link_opts__last_field old_fd
+
LIBBPF_API int bpf_set_link_xdp_fd(int ifindex, int fd, __u32 flags);
+LIBBPF_API int bpf_set_link_xdp_fd_opts(int ifindex, int fd, __u32 flags,
+ const struct bpf_xdp_set_link_opts *opts);
LIBBPF_API int bpf_get_link_xdp_id(int ifindex, __u32 *prog_id, __u32 flags);
LIBBPF_API int bpf_get_link_xdp_info(int ifindex, struct xdp_link_info *info,
size_t info_size, __u32 flags);
diff --git a/tools/lib/bpf/libbpf.map b/tools/lib/bpf/libbpf.map
index 5129283c0284..dcc87db3ca8a 100644
--- a/tools/lib/bpf/libbpf.map
+++ b/tools/lib/bpf/libbpf.map
@@ -244,4 +244,5 @@ LIBBPF_0.0.8 {
bpf_link__pin_path;
bpf_link__unpin;
bpf_program__set_attach_target;
+ bpf_set_link_xdp_fd_opts;
} LIBBPF_0.0.7;
diff --git a/tools/lib/bpf/netlink.c b/tools/lib/bpf/netlink.c
index 431bd25c6cdb..18b5319025e1 100644
--- a/tools/lib/bpf/netlink.c
+++ b/tools/lib/bpf/netlink.c
@@ -132,7 +132,8 @@ done:
return ret;
}
-int bpf_set_link_xdp_fd(int ifindex, int fd, __u32 flags)
+static int __bpf_set_link_xdp_fd_replace(int ifindex, int fd, int old_fd,
+ __u32 flags)
{
int sock, seq = 0, ret;
struct nlattr *nla, *nla_xdp;
@@ -178,6 +179,14 @@ int bpf_set_link_xdp_fd(int ifindex, int fd, __u32 flags)
nla->nla_len += nla_xdp->nla_len;
}
+ if (flags & XDP_FLAGS_REPLACE) {
+ nla_xdp = (struct nlattr *)((char *)nla + nla->nla_len);
+ nla_xdp->nla_type = IFLA_XDP_EXPECTED_FD;
+ nla_xdp->nla_len = NLA_HDRLEN + sizeof(old_fd);
+ memcpy((char *)nla_xdp + NLA_HDRLEN, &old_fd, sizeof(old_fd));
+ nla->nla_len += nla_xdp->nla_len;
+ }
+
req.nh.nlmsg_len += NLA_ALIGN(nla->nla_len);
if (send(sock, &req, req.nh.nlmsg_len, 0) < 0) {
@@ -191,6 +200,29 @@ cleanup:
return ret;
}
+int bpf_set_link_xdp_fd_opts(int ifindex, int fd, __u32 flags,
+ const struct bpf_xdp_set_link_opts *opts)
+{
+ int old_fd = -1;
+
+ if (!OPTS_VALID(opts, bpf_xdp_set_link_opts))
+ return -EINVAL;
+
+ if (OPTS_HAS(opts, old_fd)) {
+ old_fd = OPTS_GET(opts, old_fd, -1);
+ flags |= XDP_FLAGS_REPLACE;
+ }
+
+ return __bpf_set_link_xdp_fd_replace(ifindex, fd,
+ old_fd,
+ flags);
+}
+
+int bpf_set_link_xdp_fd(int ifindex, int fd, __u32 flags)
+{
+ return __bpf_set_link_xdp_fd_replace(ifindex, fd, 0, flags);
+}
+
static int __dump_link_nlmsg(struct nlmsghdr *nlh,
libbpf_dump_nlmsg_t dump_link_nlmsg, void *cookie)
{
diff --git a/tools/testing/selftests/bpf/prog_tests/xdp_attach.c b/tools/testing/selftests/bpf/prog_tests/xdp_attach.c
new file mode 100644
index 000000000000..05b294d6b923
--- /dev/null
+++ b/tools/testing/selftests/bpf/prog_tests/xdp_attach.c
@@ -0,0 +1,62 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <test_progs.h>
+
+#define IFINDEX_LO 1
+#define XDP_FLAGS_REPLACE (1U << 4)
+
+void test_xdp_attach(void)
+{
+ struct bpf_object *obj1, *obj2, *obj3;
+ const char *file = "./test_xdp.o";
+ int err, fd1, fd2, fd3;
+ __u32 duration = 0;
+ DECLARE_LIBBPF_OPTS(bpf_xdp_set_link_opts, opts,
+ .old_fd = -1);
+
+ err = bpf_prog_load(file, BPF_PROG_TYPE_XDP, &obj1, &fd1);
+ if (CHECK_FAIL(err))
+ return;
+ err = bpf_prog_load(file, BPF_PROG_TYPE_XDP, &obj2, &fd2);
+ if (CHECK_FAIL(err))
+ goto out_1;
+ err = bpf_prog_load(file, BPF_PROG_TYPE_XDP, &obj3, &fd3);
+ if (CHECK_FAIL(err))
+ goto out_2;
+
+ err = bpf_set_link_xdp_fd_opts(IFINDEX_LO, fd1, XDP_FLAGS_REPLACE,
+ &opts);
+ if (CHECK(err, "load_ok", "initial load failed"))
+ goto out_close;
+
+ err = bpf_set_link_xdp_fd_opts(IFINDEX_LO, fd2, XDP_FLAGS_REPLACE,
+ &opts);
+ if (CHECK(!err, "load_fail", "load with expected id didn't fail"))
+ goto out;
+
+ opts.old_fd = fd1;
+ err = bpf_set_link_xdp_fd_opts(IFINDEX_LO, fd2, 0, &opts);
+ if (CHECK(err, "replace_ok", "replace valid old_fd failed"))
+ goto out;
+
+ err = bpf_set_link_xdp_fd_opts(IFINDEX_LO, fd3, 0, &opts);
+ if (CHECK(!err, "replace_fail", "replace invalid old_fd didn't fail"))
+ goto out;
+
+ err = bpf_set_link_xdp_fd_opts(IFINDEX_LO, -1, 0, &opts);
+ if (CHECK(!err, "remove_fail", "remove invalid old_fd didn't fail"))
+ goto out;
+
+ opts.old_fd = fd2;
+ err = bpf_set_link_xdp_fd_opts(IFINDEX_LO, -1, 0, &opts);
+ if (CHECK(err, "remove_ok", "remove valid old_fd failed"))
+ goto out;
+
+out:
+ bpf_set_link_xdp_fd(IFINDEX_LO, -1, 0);
+out_close:
+ bpf_object__close(obj3);
+out_2:
+ bpf_object__close(obj2);
+out_1:
+ bpf_object__close(obj1);
+}
generated by cgit (git 2.34.1) at 2025-05-08 18:55:23 +0000