bpf, xdp: Extract common XDP program attachment logic
Further refactor XDP attachment code. dev_change_xdp_fd() is split into two parts: getting bpf_progs from FDs and attachment logic, working with bpf_progs. This makes attachment logic a bit more straightforward and prepares code for bpf_xdp_link inclusion, which will share the common logic. Signed-off-by: Andrii Nakryiko <andriin@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Link: https://lore.kernel.org/bpf/20200722064603.3350758-4-andriin@fb.com
This commit is contained in:
Andrii Nakryiko
Alexei Starovoitov
parent
7f0a838254
commit
d4baa9368a
173
net/core/dev.c
173
net/core/dev.c
@ -8815,6 +8815,82 @@ static void dev_xdp_uninstall(struct net_device *dev)
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}
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}
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static int dev_xdp_attach(struct net_device *dev, struct netlink_ext_ack *extack,
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struct bpf_prog *new_prog, struct bpf_prog *old_prog,
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u32 flags)
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{
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struct bpf_prog *cur_prog;
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enum bpf_xdp_mode mode;
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bpf_op_t bpf_op;
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int err;
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ASSERT_RTNL();
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/* just one XDP mode bit should be set, zero defaults to SKB mode */
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if (hweight32(flags & XDP_FLAGS_MODES) > 1) {
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NL_SET_ERR_MSG(extack, "Only one XDP mode flag can be set");
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return -EINVAL;
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}
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/* old_prog != NULL implies XDP_FLAGS_REPLACE is set */
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if (old_prog && !(flags & XDP_FLAGS_REPLACE)) {
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NL_SET_ERR_MSG(extack, "XDP_FLAGS_REPLACE is not specified");
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return -EINVAL;
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}
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mode = dev_xdp_mode(flags);
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cur_prog = dev_xdp_prog(dev, mode);
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if ((flags & XDP_FLAGS_REPLACE) && cur_prog != old_prog) {
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NL_SET_ERR_MSG(extack, "Active program does not match expected");
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return -EEXIST;
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}
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if ((flags & XDP_FLAGS_UPDATE_IF_NOEXIST) && cur_prog) {
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NL_SET_ERR_MSG(extack, "XDP program already attached");
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return -EBUSY;
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}
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if (new_prog) {
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bool offload = mode == XDP_MODE_HW;
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enum bpf_xdp_mode other_mode = mode == XDP_MODE_SKB
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? XDP_MODE_DRV : XDP_MODE_SKB;
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if (!offload && dev_xdp_prog(dev, other_mode)) {
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NL_SET_ERR_MSG(extack, "Native and generic XDP can't be active at the same time");
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return -EEXIST;
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}
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if (!offload && bpf_prog_is_dev_bound(new_prog->aux)) {
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NL_SET_ERR_MSG(extack, "Using device-bound program without HW_MODE flag is not supported");
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return -EINVAL;
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}
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if (new_prog->expected_attach_type == BPF_XDP_DEVMAP) {
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NL_SET_ERR_MSG(extack, "BPF_XDP_DEVMAP programs can not be attached to a device");
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return -EINVAL;
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}
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if (new_prog->expected_attach_type == BPF_XDP_CPUMAP) {
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NL_SET_ERR_MSG(extack, "BPF_XDP_CPUMAP programs can not be attached to a device");
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return -EINVAL;
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}
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}
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/* don't call drivers if the effective program didn't change */
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if (new_prog != cur_prog) {
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bpf_op = dev_xdp_bpf_op(dev, mode);
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if (!bpf_op) {
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NL_SET_ERR_MSG(extack, "Underlying driver does not support XDP in native mode");
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return -EOPNOTSUPP;
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}
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err = dev_xdp_install(dev, mode, bpf_op, extack, flags, new_prog);
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if (err)
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return err;
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}
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dev_xdp_set_prog(dev, mode, new_prog);
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if (cur_prog)
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bpf_prog_put(cur_prog);
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return 0;
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}
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/**
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* dev_change_xdp_fd - set or clear a bpf program for a device rx path
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* @dev: device
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@ -8828,97 +8904,38 @@ static void dev_xdp_uninstall(struct net_device *dev)
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int dev_change_xdp_fd(struct net_device *dev, struct netlink_ext_ack *extack,
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int fd, int expected_fd, u32 flags)
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{
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const struct net_device_ops *ops = dev->netdev_ops;
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enum bpf_xdp_mode mode = dev_xdp_mode(flags);
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bool offload = mode == XDP_MODE_HW;
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u32 prog_id, expected_id = 0;
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struct bpf_prog *prog;
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bpf_op_t bpf_op;
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struct bpf_prog *new_prog = NULL, *old_prog = NULL;
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int err;
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ASSERT_RTNL();
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bpf_op = dev_xdp_bpf_op(dev, mode);
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if (!bpf_op) {
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NL_SET_ERR_MSG(extack, "underlying driver does not support XDP in native mode");
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return -EOPNOTSUPP;
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}
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prog_id = dev_xdp_prog_id(dev, mode);
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if (flags & XDP_FLAGS_REPLACE) {
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if (expected_fd >= 0) {
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prog = bpf_prog_get_type_dev(expected_fd,
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BPF_PROG_TYPE_XDP,
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bpf_op == ops->ndo_bpf);
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if (IS_ERR(prog))
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return PTR_ERR(prog);
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expected_id = prog->aux->id;
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bpf_prog_put(prog);
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}
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if (prog_id != expected_id) {
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NL_SET_ERR_MSG(extack, "Active program does not match expected");
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return -EEXIST;
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}
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}
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if (fd >= 0) {
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enum bpf_xdp_mode other_mode = mode == XDP_MODE_SKB
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? XDP_MODE_DRV : XDP_MODE_SKB;
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if (!offload && dev_xdp_prog_id(dev, other_mode)) {
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NL_SET_ERR_MSG(extack, "Native and generic XDP can't be active at the same time");
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return -EEXIST;
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new_prog = bpf_prog_get_type_dev(fd, BPF_PROG_TYPE_XDP,
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mode != XDP_MODE_SKB);
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if (IS_ERR(new_prog))
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return PTR_ERR(new_prog);
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}
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if ((flags & XDP_FLAGS_UPDATE_IF_NOEXIST) && prog_id) {
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NL_SET_ERR_MSG(extack, "XDP program already attached");
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return -EBUSY;
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if (expected_fd >= 0) {
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old_prog = bpf_prog_get_type_dev(expected_fd, BPF_PROG_TYPE_XDP,
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mode != XDP_MODE_SKB);
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if (IS_ERR(old_prog)) {
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err = PTR_ERR(old_prog);
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old_prog = NULL;
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goto err_out;
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}
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}
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prog = bpf_prog_get_type_dev(fd, BPF_PROG_TYPE_XDP,
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bpf_op == ops->ndo_bpf);
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if (IS_ERR(prog))
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return PTR_ERR(prog);
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err = dev_xdp_attach(dev, extack, new_prog, old_prog, flags);
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if (!offload && bpf_prog_is_dev_bound(prog->aux)) {
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NL_SET_ERR_MSG(extack, "Using device-bound program without HW_MODE flag is not supported");
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bpf_prog_put(prog);
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return -EINVAL;
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}
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if (prog->expected_attach_type == BPF_XDP_DEVMAP) {
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NL_SET_ERR_MSG(extack, "BPF_XDP_DEVMAP programs can not be attached to a device");
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bpf_prog_put(prog);
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return -EINVAL;
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}
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if (prog->expected_attach_type == BPF_XDP_CPUMAP) {
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NL_SET_ERR_MSG(extack,
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"BPF_XDP_CPUMAP programs can not be attached to a device");
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bpf_prog_put(prog);
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return -EINVAL;
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}
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/* prog->aux->id may be 0 for orphaned device-bound progs */
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if (prog->aux->id && prog->aux->id == prog_id) {
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bpf_prog_put(prog);
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return 0;
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}
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} else {
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if (!prog_id)
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return 0;
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prog = NULL;
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}
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err = dev_xdp_install(dev, mode, bpf_op, extack, flags, prog);
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if (err < 0 && prog) {
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bpf_prog_put(prog);
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err_out:
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if (err && new_prog)
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bpf_prog_put(new_prog);
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if (old_prog)
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bpf_prog_put(old_prog);
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return err;
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}
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dev_xdp_set_prog(dev, mode, prog);
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return 0;
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}
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/**
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* dev_new_index - allocate an ifindex
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