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 @@ static int bpf_netlink_recv(int sock, __u32 nl_pid, int seq, 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 @@ int bpf_set_link_xdp_fd(int ifindex, int fd, __u32 flags) 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 + +#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); +}