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Jakub Kicinskiborkmann
Jakub Kicinski
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borkmann
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netdevsim: add bpf offload support
Add support for loading programs for netdevsim devices and expose the related information via DebugFS. Both offload of XDP and cls_bpf programs is supported. Signed-off-by: Jakub Kicinski <[email protected]> Reviewed-by: Simon Horman <[email protected]> Reviewed-by: Quentin Monnet <[email protected]> Signed-off-by: Daniel Borkmann <[email protected]>
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‎drivers/net/netdevsim/Makefile

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@@ -4,3 +4,4 @@ obj-$(CONFIG_NETDEVSIM) += netdevsim.o
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netdevsim-objs := \
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netdev.o \
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bpf.o \

‎drivers/net/netdevsim/bpf.c

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/*
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* Copyright (C) 2017 Netronome Systems, Inc.
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*
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* This software is licensed under the GNU General License Version 2,
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* June 1991 as shown in the file COPYING in the top-level directory of this
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* source tree.
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*
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* THE COPYRIGHT HOLDERS AND/OR OTHER PARTIES PROVIDE THE PROGRAM "AS IS"
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* WITHOUT WARRANTY OF ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING,
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* BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
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* FOR A PARTICULAR PURPOSE. THE ENTIRE RISK AS TO THE QUALITY AND PERFORMANCE
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* OF THE PROGRAM IS WITH YOU. SHOULD THE PROGRAM PROVE DEFECTIVE, YOU ASSUME
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* THE COST OF ALL NECESSARY SERVICING, REPAIR OR CORRECTION.
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*/
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#include <linux/bpf.h>
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#include <linux/bpf_verifier.h>
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#include <linux/debugfs.h>
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#include <linux/kernel.h>
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#include <linux/rtnetlink.h>
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#include <net/pkt_cls.h>
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#include "netdevsim.h"
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struct nsim_bpf_bound_prog {
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struct netdevsim *ns;
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struct bpf_prog *prog;
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struct dentry *ddir;
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const char *state;
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bool is_loaded;
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struct list_head l;
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};
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static int nsim_debugfs_bpf_string_read(struct seq_file *file, void *data)
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{
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const char **str = file->private;
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if (*str)
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seq_printf(file, "%s\n", *str);
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return 0;
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}
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static int nsim_debugfs_bpf_string_open(struct inode *inode, struct file *f)
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{
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return single_open(f, nsim_debugfs_bpf_string_read, inode->i_private);
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}
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static const struct file_operations nsim_bpf_string_fops = {
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.owner = THIS_MODULE,
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.open = nsim_debugfs_bpf_string_open,
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.release = single_release,
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.read = seq_read,
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.llseek = seq_lseek
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};
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static int
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nsim_bpf_verify_insn(struct bpf_verifier_env *env, int insn_idx, int prev_insn)
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{
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struct nsim_bpf_bound_prog *state;
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state = env->prog->aux->offload->dev_priv;
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if (state->ns->bpf_bind_verifier_delay && !insn_idx)
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msleep(state->ns->bpf_bind_verifier_delay);
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return 0;
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}
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static const struct bpf_ext_analyzer_ops nsim_bpf_analyzer_ops = {
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.insn_hook = nsim_bpf_verify_insn,
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};
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static bool nsim_xdp_offload_active(struct netdevsim *ns)
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{
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return ns->xdp_prog_mode == XDP_ATTACHED_HW;
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}
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static void nsim_prog_set_loaded(struct bpf_prog *prog, bool loaded)
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{
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struct nsim_bpf_bound_prog *state;
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if (!prog || !prog->aux->offload)
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return;
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state = prog->aux->offload->dev_priv;
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state->is_loaded = loaded;
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}
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static int
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nsim_bpf_offload(struct netdevsim *ns, struct bpf_prog *prog, bool oldprog)
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{
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nsim_prog_set_loaded(ns->bpf_offloaded, false);
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WARN(!!ns->bpf_offloaded != oldprog,
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"bad offload state, expected offload %sto be active",
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oldprog ? "" : "not ");
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ns->bpf_offloaded = prog;
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ns->bpf_offloaded_id = prog ? prog->aux->id : 0;
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nsim_prog_set_loaded(prog, true);
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return 0;
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}
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int nsim_bpf_setup_tc_block_cb(enum tc_setup_type type,
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void *type_data, void *cb_priv)
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{
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struct tc_cls_bpf_offload *cls_bpf = type_data;
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struct bpf_prog *prog = cls_bpf->prog;
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struct netdevsim *ns = cb_priv;
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bool skip_sw;
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if (type != TC_SETUP_CLSBPF ||
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!tc_can_offload(ns->netdev) ||
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cls_bpf->common.protocol != htons(ETH_P_ALL) ||
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cls_bpf->common.chain_index)
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return -EOPNOTSUPP;
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skip_sw = cls_bpf->gen_flags & TCA_CLS_FLAGS_SKIP_SW;
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if (nsim_xdp_offload_active(ns))
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return -EBUSY;
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if (!ns->bpf_tc_accept)
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return -EOPNOTSUPP;
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/* Note: progs without skip_sw will probably not be dev bound */
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if (prog && !prog->aux->offload && !ns->bpf_tc_non_bound_accept)
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return -EOPNOTSUPP;
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switch (cls_bpf->command) {
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case TC_CLSBPF_REPLACE:
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return nsim_bpf_offload(ns, prog, true);
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case TC_CLSBPF_ADD:
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return nsim_bpf_offload(ns, prog, false);
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case TC_CLSBPF_DESTROY:
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return nsim_bpf_offload(ns, NULL, true);
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default:
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return -EOPNOTSUPP;
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}
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}
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int nsim_bpf_disable_tc(struct netdevsim *ns)
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{
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if (ns->bpf_offloaded && !nsim_xdp_offload_active(ns))
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return -EBUSY;
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return 0;
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}
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static int nsim_xdp_offload_prog(struct netdevsim *ns, struct netdev_bpf *bpf)
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{
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if (!nsim_xdp_offload_active(ns) && !bpf->prog)
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return 0;
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if (!nsim_xdp_offload_active(ns) && bpf->prog && ns->bpf_offloaded) {
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NSIM_EA(bpf->extack, "TC program is already loaded");
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return -EBUSY;
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}
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return nsim_bpf_offload(ns, bpf->prog, nsim_xdp_offload_active(ns));
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}
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static int nsim_xdp_set_prog(struct netdevsim *ns, struct netdev_bpf *bpf)
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{
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int err;
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if (ns->xdp_prog && (bpf->flags ^ ns->xdp_flags) & XDP_FLAGS_MODES) {
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NSIM_EA(bpf->extack, "program loaded with different flags");
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return -EBUSY;
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}
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if (bpf->command == XDP_SETUP_PROG && !ns->bpf_xdpdrv_accept) {
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NSIM_EA(bpf->extack, "driver XDP disabled in DebugFS");
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return -EOPNOTSUPP;
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}
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if (bpf->command == XDP_SETUP_PROG_HW && !ns->bpf_xdpoffload_accept) {
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NSIM_EA(bpf->extack, "XDP offload disabled in DebugFS");
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return -EOPNOTSUPP;
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}
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if (bpf->command == XDP_SETUP_PROG_HW) {
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err = nsim_xdp_offload_prog(ns, bpf);
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if (err)
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return err;
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}
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if (ns->xdp_prog)
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bpf_prog_put(ns->xdp_prog);
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ns->xdp_prog = bpf->prog;
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ns->xdp_flags = bpf->flags;
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if (!bpf->prog)
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ns->xdp_prog_mode = XDP_ATTACHED_NONE;
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else if (bpf->command == XDP_SETUP_PROG)
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ns->xdp_prog_mode = XDP_ATTACHED_DRV;
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else
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ns->xdp_prog_mode = XDP_ATTACHED_HW;
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return 0;
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}
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int nsim_bpf_create_prog(struct netdevsim *ns, struct bpf_prog *prog)
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{
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struct nsim_bpf_bound_prog *state;
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char name[16];
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int err;
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state = kzalloc(sizeof(*state), GFP_KERNEL);
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if (!state)
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return -ENOMEM;
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state->ns = ns;
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state->prog = prog;
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state->state = "verify";
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/* Program id is not populated yet when we create the state. */
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sprintf(name, "%u", ns->prog_id_gen++);
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state->ddir = debugfs_create_dir(name, ns->ddir_bpf_bound_progs);
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if (IS_ERR(state->ddir)) {
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err = PTR_ERR(state->ddir);
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kfree(state);
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return err;
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}
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debugfs_create_u32("id", 0400, state->ddir, &prog->aux->id);
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debugfs_create_file("state", 0400, state->ddir,
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&state->state, &nsim_bpf_string_fops);
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debugfs_create_bool("loaded", 0400, state->ddir, &state->is_loaded);
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list_add_tail(&state->l, &ns->bpf_bound_progs);
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prog->aux->offload->dev_priv = state;
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return 0;
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}
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void nsim_bpf_destroy_prog(struct bpf_prog *prog)
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{
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struct nsim_bpf_bound_prog *state;
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state = prog->aux->offload->dev_priv;
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WARN(state->is_loaded,
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"offload state destroyed while program still bound");
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debugfs_remove_recursive(state->ddir);
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list_del(&state->l);
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kfree(state);
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}
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static int nsim_setup_prog_checks(struct netdevsim *ns, struct netdev_bpf *bpf)
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{
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if (bpf->prog && bpf->prog->aux->offload) {
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NSIM_EA(bpf->extack, "attempt to load offloaded prog to drv");
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return -EINVAL;
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}
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if (ns->netdev->mtu > NSIM_XDP_MAX_MTU) {
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NSIM_EA(bpf->extack, "MTU too large w/ XDP enabled");
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return -EINVAL;
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}
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if (nsim_xdp_offload_active(ns)) {
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NSIM_EA(bpf->extack, "xdp offload active, can't load drv prog");
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return -EBUSY;
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}
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return 0;
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}
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static int
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nsim_setup_prog_hw_checks(struct netdevsim *ns, struct netdev_bpf *bpf)
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{
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struct nsim_bpf_bound_prog *state;
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if (!bpf->prog)
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return 0;
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if (!bpf->prog->aux->offload) {
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NSIM_EA(bpf->extack, "xdpoffload of non-bound program");
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return -EINVAL;
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}
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if (bpf->prog->aux->offload->netdev != ns->netdev) {
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NSIM_EA(bpf->extack, "program bound to different dev");
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return -EINVAL;
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}
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state = bpf->prog->aux->offload->dev_priv;
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if (WARN_ON(strcmp(state->state, "xlated"))) {
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NSIM_EA(bpf->extack, "offloading program in bad state");
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return -EINVAL;
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}
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return 0;
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}
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int nsim_bpf(struct net_device *dev, struct netdev_bpf *bpf)
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{
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struct netdevsim *ns = netdev_priv(dev);
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struct nsim_bpf_bound_prog *state;
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int err;
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ASSERT_RTNL();
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switch (bpf->command) {
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case BPF_OFFLOAD_VERIFIER_PREP:
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if (!ns->bpf_bind_accept)
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return -EOPNOTSUPP;
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err = nsim_bpf_create_prog(ns, bpf->verifier.prog);
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if (err)
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return err;
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bpf->verifier.ops = &nsim_bpf_analyzer_ops;
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return 0;
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case BPF_OFFLOAD_TRANSLATE:
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state = bpf->offload.prog->aux->offload->dev_priv;
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state->state = "xlated";
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return 0;
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case BPF_OFFLOAD_DESTROY:
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nsim_bpf_destroy_prog(bpf->offload.prog);
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return 0;
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case XDP_QUERY_PROG:
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bpf->prog_attached = ns->xdp_prog_mode;
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bpf->prog_id = ns->xdp_prog ? ns->xdp_prog->aux->id : 0;
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bpf->prog_flags = ns->xdp_prog ? ns->xdp_flags : 0;
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return 0;
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case XDP_SETUP_PROG:
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err = nsim_setup_prog_checks(ns, bpf);
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if (err)
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return err;
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return nsim_xdp_set_prog(ns, bpf);
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case XDP_SETUP_PROG_HW:
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err = nsim_setup_prog_hw_checks(ns, bpf);
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if (err)
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return err;
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return nsim_xdp_set_prog(ns, bpf);
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default:
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return -EINVAL;
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}
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}
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int nsim_bpf_init(struct netdevsim *ns)
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{
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INIT_LIST_HEAD(&ns->bpf_bound_progs);
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debugfs_create_u32("bpf_offloaded_id", 0400, ns->ddir,
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&ns->bpf_offloaded_id);
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ns->bpf_bind_accept = true;
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debugfs_create_bool("bpf_bind_accept", 0600, ns->ddir,
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&ns->bpf_bind_accept);
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debugfs_create_u32("bpf_bind_verifier_delay", 0600, ns->ddir,
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&ns->bpf_bind_verifier_delay);
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ns->ddir_bpf_bound_progs =
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debugfs_create_dir("bpf_bound_progs", ns->ddir);
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ns->bpf_tc_accept = true;
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debugfs_create_bool("bpf_tc_accept", 0600, ns->ddir,
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&ns->bpf_tc_accept);
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debugfs_create_bool("bpf_tc_non_bound_accept", 0600, ns->ddir,
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&ns->bpf_tc_non_bound_accept);
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ns->bpf_xdpdrv_accept = true;
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debugfs_create_bool("bpf_xdpdrv_accept", 0600, ns->ddir,
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&ns->bpf_xdpdrv_accept);
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ns->bpf_xdpoffload_accept = true;
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debugfs_create_bool("bpf_xdpoffload_accept", 0600, ns->ddir,
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&ns->bpf_xdpoffload_accept);
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return 0;
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}
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void nsim_bpf_uninit(struct netdevsim *ns)
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{
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WARN_ON(!list_empty(&ns->bpf_bound_progs));
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WARN_ON(ns->xdp_prog);
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WARN_ON(ns->bpf_offloaded);
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}

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