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