/* * Copyright (c) 2015 Jiri Pirko <jiri@resnulli.us> * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation; either version 2 of the License, or * (at your option) any later version. */ #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 <linux/tc_act/tc_bpf.h> #include <net/tc_act/tc_bpf.h> #define BPF_TAB_MASK 15 #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(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_end(skb); filter_res = BPF_PROG_RUN(filter, skb); __skb_pull(skb, skb->mac_len); } else { bpf_compute_data_end(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; 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 = prog->tcf_refcnt - ref, .bindcnt = prog->tcf_bindcnt - bind, .action = prog->tcf_action, }; struct tcf_t tm; int ret; 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; return skb->len; nla_put_failure: 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 = kzalloc(bpf_size, GFP_KERNEL); if (bpf_ops == NULL) return -ENOMEM; memcpy(bpf_ops, nla_data(tb[TCA_ACT_BPF_OPS]), bpf_size); 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) { if (cfg->is_ebpf) bpf_prog_put(cfg->filter); else bpf_prog_destroy(cfg->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 rtnl 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) { struct tc_action_net *tn = net_generic(net, bpf_net_id); struct nlattr *tb[TCA_ACT_BPF_MAX + 1]; struct tcf_bpf_cfg cfg, old; struct tc_act_bpf *parm; struct tcf_bpf *prog; bool is_bpf, is_ebpf; int ret, res = 0; if (!nla) return -EINVAL; ret = nla_parse_nested(tb, TCA_ACT_BPF_MAX, nla, act_bpf_policy); if (ret < 0) return ret; if (!tb[TCA_ACT_BPF_PARMS]) return -EINVAL; parm = nla_data(tb[TCA_ACT_BPF_PARMS]); if (!tcf_hash_check(tn, parm->index, act, bind)) { ret = tcf_hash_create(tn, parm->index, est, act, &act_bpf_ops, bind, true); if (ret < 0) return ret; res = ACT_P_CREATED; } else { /* Don't override defaults. */ if (bind) return 0; tcf_hash_release(*act, bind); if (!replace) return -EEXIST; } 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 out; } 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 out; prog = to_bpf(*act); ASSERT_RTNL(); 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; prog->tcf_action = parm->action; rcu_assign_pointer(prog->filter, cfg.filter); if (res == ACT_P_CREATED) { tcf_hash_insert(tn, *act); } else { /* make sure the program being replaced is no longer executing */ synchronize_rcu(); tcf_bpf_cfg_cleanup(&old); } return res; out: if (res == ACT_P_CREATED) tcf_hash_cleanup(*act, est); return ret; } static void tcf_bpf_cleanup(struct tc_action *act, int bind) { 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 tc_action_net *tn = net_generic(net, bpf_net_id); return tcf_generic_walker(tn, skb, cb, type, ops); } 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_hash_search(tn, a, index); } static struct tc_action_ops act_bpf_ops __read_mostly = { .kind = "bpf", .type = TCA_ACT_BPF, .owner = THIS_MODULE, .act = tcf_bpf, .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, BPF_TAB_MASK); } static void __net_exit bpf_exit_net(struct net *net) { struct tc_action_net *tn = net_generic(net, bpf_net_id); tc_action_net_exit(tn); } static struct pernet_operations bpf_net_ops = { .init = bpf_init_net, .exit = 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");