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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-07 18:49:45 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-07 18:49:45 +0000 |
commit | 2c3c1048746a4622d8c89a29670120dc8fab93c4 (patch) | |
tree | 848558de17fb3008cdf4d861b01ac7781903ce39 /net/sched/act_bpf.c | |
parent | Initial commit. (diff) | |
download | linux-2c3c1048746a4622d8c89a29670120dc8fab93c4.tar.xz linux-2c3c1048746a4622d8c89a29670120dc8fab93c4.zip |
Adding upstream version 6.1.76.upstream/6.1.76
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'net/sched/act_bpf.c')
-rw-r--r-- | net/sched/act_bpf.c | 437 |
1 files changed, 437 insertions, 0 deletions
diff --git a/net/sched/act_bpf.c b/net/sched/act_bpf.c new file mode 100644 index 000000000..b79eee44e --- /dev/null +++ b/net/sched/act_bpf.c @@ -0,0 +1,437 @@ +// 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/sock.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 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_update(this_cpu_ptr(prog->common.cpu_bstats), skb); + + 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); + } + if (unlikely(!skb->tstamp && skb->mono_delivery_time)) + skb->mono_delivery_time = 0; + if (skb_sk_is_prefetched(skb) && filter_res != TC_ACT_OK) + skb_orphan(skb); + + /* 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 unknown, 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, + struct tcf_proto *tp, u32 flags, + struct netlink_ext_ack *extack) +{ + struct tc_action_net *tn = net_generic(net, act_bpf_ops.net_id); + bool bind = flags & TCA_ACT_FLAGS_BIND; + 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, flags); + 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 (!(flags & TCA_ACT_FLAGS_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) { + 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) { + /* 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 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, + .size = sizeof(struct tcf_bpf), +}; + +static __net_init int bpf_init_net(struct net *net) +{ + struct tc_action_net *tn = net_generic(net, act_bpf_ops.net_id); + + return tc_action_net_init(net, tn, &act_bpf_ops); +} + +static void __net_exit bpf_exit_net(struct list_head *net_list) +{ + tc_action_net_exit(net_list, act_bpf_ops.net_id); +} + +static struct pernet_operations bpf_net_ops = { + .init = bpf_init_net, + .exit_batch = bpf_exit_net, + .id = &act_bpf_ops.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"); |