| // SPDX-License-Identifier: GPL-2.0-or-later |
| /* |
| * Copyright (c) 2015 Jiri Pirko <jiri@resnulli.us> |
| */ |
| |
| #include <linux/module.h> |
| #include <linux/init.h> |
| #include <linux/kernel.h> |
| #include <linux/skbuff.h> |
| #include <linux/rtnetlink.h> |
| #include <linux/filter.h> |
| #include <linux/bpf.h> |
| |
| #include <net/netlink.h> |
| #include <net/pkt_sched.h> |
| #include <net/pkt_cls.h> |
| |
| #include <linux/tc_act/tc_bpf.h> |
| #include <net/tc_act/tc_bpf.h> |
| |
| #define ACT_BPF_NAME_LEN 256 |
| |
| struct tcf_bpf_cfg { |
| struct bpf_prog *filter; |
| struct sock_filter *bpf_ops; |
| const char *bpf_name; |
| u16 bpf_num_ops; |
| bool is_ebpf; |
| }; |
| |
| static unsigned int bpf_net_id; |
| static struct tc_action_ops act_bpf_ops; |
| |
| static int tcf_bpf_act(struct sk_buff *skb, const struct tc_action *act, |
| struct tcf_result *res) |
| { |
| bool at_ingress = skb_at_tc_ingress(skb); |
| struct tcf_bpf *prog = to_bpf(act); |
| struct bpf_prog *filter; |
| int action, filter_res; |
| |
| tcf_lastuse_update(&prog->tcf_tm); |
| bstats_cpu_update(this_cpu_ptr(prog->common.cpu_bstats), skb); |
| |
| rcu_read_lock(); |
| filter = rcu_dereference(prog->filter); |
| if (at_ingress) { |
| __skb_push(skb, skb->mac_len); |
| bpf_compute_data_pointers(skb); |
| filter_res = BPF_PROG_RUN(filter, skb); |
| __skb_pull(skb, skb->mac_len); |
| } else { |
| bpf_compute_data_pointers(skb); |
| filter_res = BPF_PROG_RUN(filter, skb); |
| } |
| rcu_read_unlock(); |
| |
| /* A BPF program may overwrite the default action opcode. |
| * Similarly as in cls_bpf, if filter_res == -1 we use the |
| * default action specified from tc. |
| * |
| * In case a different well-known TC_ACT opcode has been |
| * returned, it will overwrite the default one. |
| * |
| * For everything else that is unkown, TC_ACT_UNSPEC is |
| * returned. |
| */ |
| switch (filter_res) { |
| case TC_ACT_PIPE: |
| case TC_ACT_RECLASSIFY: |
| case TC_ACT_OK: |
| case TC_ACT_REDIRECT: |
| action = filter_res; |
| break; |
| case TC_ACT_SHOT: |
| action = filter_res; |
| qstats_drop_inc(this_cpu_ptr(prog->common.cpu_qstats)); |
| break; |
| case TC_ACT_UNSPEC: |
| action = prog->tcf_action; |
| break; |
| default: |
| action = TC_ACT_UNSPEC; |
| break; |
| } |
| |
| return action; |
| } |
| |
| static bool tcf_bpf_is_ebpf(const struct tcf_bpf *prog) |
| { |
| return !prog->bpf_ops; |
| } |
| |
| static int tcf_bpf_dump_bpf_info(const struct tcf_bpf *prog, |
| struct sk_buff *skb) |
| { |
| struct nlattr *nla; |
| |
| if (nla_put_u16(skb, TCA_ACT_BPF_OPS_LEN, prog->bpf_num_ops)) |
| return -EMSGSIZE; |
| |
| nla = nla_reserve(skb, TCA_ACT_BPF_OPS, prog->bpf_num_ops * |
| sizeof(struct sock_filter)); |
| if (nla == NULL) |
| return -EMSGSIZE; |
| |
| memcpy(nla_data(nla), prog->bpf_ops, nla_len(nla)); |
| |
| return 0; |
| } |
| |
| static int tcf_bpf_dump_ebpf_info(const struct tcf_bpf *prog, |
| struct sk_buff *skb) |
| { |
| struct nlattr *nla; |
| |
| if (prog->bpf_name && |
| nla_put_string(skb, TCA_ACT_BPF_NAME, prog->bpf_name)) |
| return -EMSGSIZE; |
| |
| if (nla_put_u32(skb, TCA_ACT_BPF_ID, prog->filter->aux->id)) |
| return -EMSGSIZE; |
| |
| nla = nla_reserve(skb, TCA_ACT_BPF_TAG, sizeof(prog->filter->tag)); |
| if (nla == NULL) |
| return -EMSGSIZE; |
| |
| memcpy(nla_data(nla), prog->filter->tag, nla_len(nla)); |
| |
| return 0; |
| } |
| |
| static int tcf_bpf_dump(struct sk_buff *skb, struct tc_action *act, |
| int bind, int ref) |
| { |
| unsigned char *tp = skb_tail_pointer(skb); |
| struct tcf_bpf *prog = to_bpf(act); |
| struct tc_act_bpf opt = { |
| .index = prog->tcf_index, |
| .refcnt = refcount_read(&prog->tcf_refcnt) - ref, |
| .bindcnt = atomic_read(&prog->tcf_bindcnt) - bind, |
| }; |
| struct tcf_t tm; |
| int ret; |
| |
| spin_lock_bh(&prog->tcf_lock); |
| opt.action = prog->tcf_action; |
| if (nla_put(skb, TCA_ACT_BPF_PARMS, sizeof(opt), &opt)) |
| goto nla_put_failure; |
| |
| if (tcf_bpf_is_ebpf(prog)) |
| ret = tcf_bpf_dump_ebpf_info(prog, skb); |
| else |
| ret = tcf_bpf_dump_bpf_info(prog, skb); |
| if (ret) |
| goto nla_put_failure; |
| |
| tcf_tm_dump(&tm, &prog->tcf_tm); |
| if (nla_put_64bit(skb, TCA_ACT_BPF_TM, sizeof(tm), &tm, |
| TCA_ACT_BPF_PAD)) |
| goto nla_put_failure; |
| |
| spin_unlock_bh(&prog->tcf_lock); |
| return skb->len; |
| |
| nla_put_failure: |
| spin_unlock_bh(&prog->tcf_lock); |
| nlmsg_trim(skb, tp); |
| return -1; |
| } |
| |
| static const struct nla_policy act_bpf_policy[TCA_ACT_BPF_MAX + 1] = { |
| [TCA_ACT_BPF_PARMS] = { .len = sizeof(struct tc_act_bpf) }, |
| [TCA_ACT_BPF_FD] = { .type = NLA_U32 }, |
| [TCA_ACT_BPF_NAME] = { .type = NLA_NUL_STRING, |
| .len = ACT_BPF_NAME_LEN }, |
| [TCA_ACT_BPF_OPS_LEN] = { .type = NLA_U16 }, |
| [TCA_ACT_BPF_OPS] = { .type = NLA_BINARY, |
| .len = sizeof(struct sock_filter) * BPF_MAXINSNS }, |
| }; |
| |
| static int tcf_bpf_init_from_ops(struct nlattr **tb, struct tcf_bpf_cfg *cfg) |
| { |
| struct sock_filter *bpf_ops; |
| struct sock_fprog_kern fprog_tmp; |
| struct bpf_prog *fp; |
| u16 bpf_size, bpf_num_ops; |
| int ret; |
| |
| bpf_num_ops = nla_get_u16(tb[TCA_ACT_BPF_OPS_LEN]); |
| if (bpf_num_ops > BPF_MAXINSNS || bpf_num_ops == 0) |
| return -EINVAL; |
| |
| bpf_size = bpf_num_ops * sizeof(*bpf_ops); |
| if (bpf_size != nla_len(tb[TCA_ACT_BPF_OPS])) |
| return -EINVAL; |
| |
| bpf_ops = kmemdup(nla_data(tb[TCA_ACT_BPF_OPS]), bpf_size, GFP_KERNEL); |
| if (bpf_ops == NULL) |
| return -ENOMEM; |
| |
| fprog_tmp.len = bpf_num_ops; |
| fprog_tmp.filter = bpf_ops; |
| |
| ret = bpf_prog_create(&fp, &fprog_tmp); |
| if (ret < 0) { |
| kfree(bpf_ops); |
| return ret; |
| } |
| |
| cfg->bpf_ops = bpf_ops; |
| cfg->bpf_num_ops = bpf_num_ops; |
| cfg->filter = fp; |
| cfg->is_ebpf = false; |
| |
| return 0; |
| } |
| |
| static int tcf_bpf_init_from_efd(struct nlattr **tb, struct tcf_bpf_cfg *cfg) |
| { |
| struct bpf_prog *fp; |
| char *name = NULL; |
| u32 bpf_fd; |
| |
| bpf_fd = nla_get_u32(tb[TCA_ACT_BPF_FD]); |
| |
| fp = bpf_prog_get_type(bpf_fd, BPF_PROG_TYPE_SCHED_ACT); |
| if (IS_ERR(fp)) |
| return PTR_ERR(fp); |
| |
| if (tb[TCA_ACT_BPF_NAME]) { |
| name = nla_memdup(tb[TCA_ACT_BPF_NAME], GFP_KERNEL); |
| if (!name) { |
| bpf_prog_put(fp); |
| return -ENOMEM; |
| } |
| } |
| |
| cfg->bpf_name = name; |
| cfg->filter = fp; |
| cfg->is_ebpf = true; |
| |
| return 0; |
| } |
| |
| static void tcf_bpf_cfg_cleanup(const struct tcf_bpf_cfg *cfg) |
| { |
| struct bpf_prog *filter = cfg->filter; |
| |
| if (filter) { |
| if (cfg->is_ebpf) |
| bpf_prog_put(filter); |
| else |
| bpf_prog_destroy(filter); |
| } |
| |
| kfree(cfg->bpf_ops); |
| kfree(cfg->bpf_name); |
| } |
| |
| static void tcf_bpf_prog_fill_cfg(const struct tcf_bpf *prog, |
| struct tcf_bpf_cfg *cfg) |
| { |
| cfg->is_ebpf = tcf_bpf_is_ebpf(prog); |
| /* updates to prog->filter are prevented, since it's called either |
| * with tcf lock or during final cleanup in rcu callback |
| */ |
| cfg->filter = rcu_dereference_protected(prog->filter, 1); |
| |
| cfg->bpf_ops = prog->bpf_ops; |
| cfg->bpf_name = prog->bpf_name; |
| } |
| |
| static int tcf_bpf_init(struct net *net, struct nlattr *nla, |
| struct nlattr *est, struct tc_action **act, |
| int replace, int bind, bool rtnl_held, |
| struct tcf_proto *tp, struct netlink_ext_ack *extack) |
| { |
| struct tc_action_net *tn = net_generic(net, bpf_net_id); |
| struct nlattr *tb[TCA_ACT_BPF_MAX + 1]; |
| struct tcf_chain *goto_ch = NULL; |
| struct tcf_bpf_cfg cfg, old; |
| struct tc_act_bpf *parm; |
| struct tcf_bpf *prog; |
| bool is_bpf, is_ebpf; |
| int ret, res = 0; |
| u32 index; |
| |
| if (!nla) |
| return -EINVAL; |
| |
| ret = nla_parse_nested_deprecated(tb, TCA_ACT_BPF_MAX, nla, |
| act_bpf_policy, NULL); |
| if (ret < 0) |
| return ret; |
| |
| if (!tb[TCA_ACT_BPF_PARMS]) |
| return -EINVAL; |
| |
| parm = nla_data(tb[TCA_ACT_BPF_PARMS]); |
| index = parm->index; |
| ret = tcf_idr_check_alloc(tn, &index, act, bind); |
| if (!ret) { |
| ret = tcf_idr_create(tn, index, est, act, |
| &act_bpf_ops, bind, true); |
| if (ret < 0) { |
| tcf_idr_cleanup(tn, index); |
| return ret; |
| } |
| |
| res = ACT_P_CREATED; |
| } else if (ret > 0) { |
| /* Don't override defaults. */ |
| if (bind) |
| return 0; |
| |
| if (!replace) { |
| tcf_idr_release(*act, bind); |
| return -EEXIST; |
| } |
| } else { |
| return ret; |
| } |
| |
| ret = tcf_action_check_ctrlact(parm->action, tp, &goto_ch, extack); |
| if (ret < 0) |
| goto release_idr; |
| |
| is_bpf = tb[TCA_ACT_BPF_OPS_LEN] && tb[TCA_ACT_BPF_OPS]; |
| is_ebpf = tb[TCA_ACT_BPF_FD]; |
| |
| if ((!is_bpf && !is_ebpf) || (is_bpf && is_ebpf)) { |
| ret = -EINVAL; |
| goto put_chain; |
| } |
| |
| memset(&cfg, 0, sizeof(cfg)); |
| |
| ret = is_bpf ? tcf_bpf_init_from_ops(tb, &cfg) : |
| tcf_bpf_init_from_efd(tb, &cfg); |
| if (ret < 0) |
| goto put_chain; |
| |
| prog = to_bpf(*act); |
| |
| spin_lock_bh(&prog->tcf_lock); |
| if (res != ACT_P_CREATED) |
| tcf_bpf_prog_fill_cfg(prog, &old); |
| |
| prog->bpf_ops = cfg.bpf_ops; |
| prog->bpf_name = cfg.bpf_name; |
| |
| if (cfg.bpf_num_ops) |
| prog->bpf_num_ops = cfg.bpf_num_ops; |
| |
| goto_ch = tcf_action_set_ctrlact(*act, parm->action, goto_ch); |
| rcu_assign_pointer(prog->filter, cfg.filter); |
| spin_unlock_bh(&prog->tcf_lock); |
| |
| if (goto_ch) |
| tcf_chain_put_by_act(goto_ch); |
| |
| if (res == ACT_P_CREATED) { |
| tcf_idr_insert(tn, *act); |
| } else { |
| /* make sure the program being replaced is no longer executing */ |
| synchronize_rcu(); |
| tcf_bpf_cfg_cleanup(&old); |
| } |
| |
| return res; |
| |
| put_chain: |
| if (goto_ch) |
| tcf_chain_put_by_act(goto_ch); |
| |
| release_idr: |
| tcf_idr_release(*act, bind); |
| return ret; |
| } |
| |
| static void tcf_bpf_cleanup(struct tc_action *act) |
| { |
| struct tcf_bpf_cfg tmp; |
| |
| tcf_bpf_prog_fill_cfg(to_bpf(act), &tmp); |
| tcf_bpf_cfg_cleanup(&tmp); |
| } |
| |
| static int tcf_bpf_walker(struct net *net, struct sk_buff *skb, |
| struct netlink_callback *cb, int type, |
| const struct tc_action_ops *ops, |
| struct netlink_ext_ack *extack) |
| { |
| struct tc_action_net *tn = net_generic(net, bpf_net_id); |
| |
| return tcf_generic_walker(tn, skb, cb, type, ops, extack); |
| } |
| |
| static int tcf_bpf_search(struct net *net, struct tc_action **a, u32 index) |
| { |
| struct tc_action_net *tn = net_generic(net, bpf_net_id); |
| |
| return tcf_idr_search(tn, a, index); |
| } |
| |
| static struct tc_action_ops act_bpf_ops __read_mostly = { |
| .kind = "bpf", |
| .id = TCA_ID_BPF, |
| .owner = THIS_MODULE, |
| .act = tcf_bpf_act, |
| .dump = tcf_bpf_dump, |
| .cleanup = tcf_bpf_cleanup, |
| .init = tcf_bpf_init, |
| .walk = tcf_bpf_walker, |
| .lookup = tcf_bpf_search, |
| .size = sizeof(struct tcf_bpf), |
| }; |
| |
| static __net_init int bpf_init_net(struct net *net) |
| { |
| struct tc_action_net *tn = net_generic(net, bpf_net_id); |
| |
| return tc_action_net_init(tn, &act_bpf_ops); |
| } |
| |
| static void __net_exit bpf_exit_net(struct list_head *net_list) |
| { |
| tc_action_net_exit(net_list, bpf_net_id); |
| } |
| |
| static struct pernet_operations bpf_net_ops = { |
| .init = bpf_init_net, |
| .exit_batch = bpf_exit_net, |
| .id = &bpf_net_id, |
| .size = sizeof(struct tc_action_net), |
| }; |
| |
| static int __init bpf_init_module(void) |
| { |
| return tcf_register_action(&act_bpf_ops, &bpf_net_ops); |
| } |
| |
| static void __exit bpf_cleanup_module(void) |
| { |
| tcf_unregister_action(&act_bpf_ops, &bpf_net_ops); |
| } |
| |
| module_init(bpf_init_module); |
| module_exit(bpf_cleanup_module); |
| |
| MODULE_AUTHOR("Jiri Pirko <jiri@resnulli.us>"); |
| MODULE_DESCRIPTION("TC BPF based action"); |
| MODULE_LICENSE("GPL v2"); |