| /* |
| * Berkeley Packet Filter based traffic classifier |
| * |
| * Might be used to classify traffic through flexible, user-defined and |
| * possibly JIT-ed BPF filters for traffic control as an alternative to |
| * ematches. |
| * |
| * (C) 2013 Daniel Borkmann <dborkman@redhat.com> |
| * |
| * This program is free software; you can redistribute it and/or modify |
| * it under the terms of the GNU General Public License version 2 as |
| * published by the Free Software Foundation. |
| */ |
| |
| #include <linux/module.h> |
| #include <linux/types.h> |
| #include <linux/skbuff.h> |
| #include <linux/filter.h> |
| #include <linux/bpf.h> |
| |
| #include <net/rtnetlink.h> |
| #include <net/pkt_cls.h> |
| #include <net/sock.h> |
| |
| MODULE_LICENSE("GPL"); |
| MODULE_AUTHOR("Daniel Borkmann <dborkman@redhat.com>"); |
| MODULE_DESCRIPTION("TC BPF based classifier"); |
| |
| #define CLS_BPF_NAME_LEN 256 |
| #define CLS_BPF_SUPPORTED_GEN_FLAGS \ |
| (TCA_CLS_FLAGS_SKIP_HW | TCA_CLS_FLAGS_SKIP_SW) |
| |
| struct cls_bpf_head { |
| struct list_head plist; |
| u32 hgen; |
| struct rcu_head rcu; |
| }; |
| |
| struct cls_bpf_prog { |
| struct bpf_prog *filter; |
| struct list_head link; |
| struct tcf_result res; |
| bool exts_integrated; |
| bool offloaded; |
| u32 gen_flags; |
| struct tcf_exts exts; |
| u32 handle; |
| union { |
| u32 bpf_fd; |
| u16 bpf_num_ops; |
| }; |
| struct sock_filter *bpf_ops; |
| const char *bpf_name; |
| struct tcf_proto *tp; |
| struct rcu_head rcu; |
| }; |
| |
| static const struct nla_policy bpf_policy[TCA_BPF_MAX + 1] = { |
| [TCA_BPF_CLASSID] = { .type = NLA_U32 }, |
| [TCA_BPF_FLAGS] = { .type = NLA_U32 }, |
| [TCA_BPF_FLAGS_GEN] = { .type = NLA_U32 }, |
| [TCA_BPF_FD] = { .type = NLA_U32 }, |
| [TCA_BPF_NAME] = { .type = NLA_NUL_STRING, |
| .len = CLS_BPF_NAME_LEN }, |
| [TCA_BPF_OPS_LEN] = { .type = NLA_U16 }, |
| [TCA_BPF_OPS] = { .type = NLA_BINARY, |
| .len = sizeof(struct sock_filter) * BPF_MAXINSNS }, |
| }; |
| |
| static int cls_bpf_exec_opcode(int code) |
| { |
| switch (code) { |
| case TC_ACT_OK: |
| case TC_ACT_SHOT: |
| case TC_ACT_STOLEN: |
| case TC_ACT_REDIRECT: |
| case TC_ACT_UNSPEC: |
| return code; |
| default: |
| return TC_ACT_UNSPEC; |
| } |
| } |
| |
| static int cls_bpf_classify(struct sk_buff *skb, const struct tcf_proto *tp, |
| struct tcf_result *res) |
| { |
| struct cls_bpf_head *head = rcu_dereference_bh(tp->root); |
| bool at_ingress = skb_at_tc_ingress(skb); |
| struct cls_bpf_prog *prog; |
| int ret = -1; |
| |
| /* Needed here for accessing maps. */ |
| rcu_read_lock(); |
| list_for_each_entry_rcu(prog, &head->plist, link) { |
| int filter_res; |
| |
| qdisc_skb_cb(skb)->tc_classid = prog->res.classid; |
| |
| if (tc_skip_sw(prog->gen_flags)) { |
| filter_res = prog->exts_integrated ? TC_ACT_UNSPEC : 0; |
| } else if (at_ingress) { |
| /* It is safe to push/pull even if skb_shared() */ |
| __skb_push(skb, skb->mac_len); |
| bpf_compute_data_end(skb); |
| filter_res = BPF_PROG_RUN(prog->filter, skb); |
| __skb_pull(skb, skb->mac_len); |
| } else { |
| bpf_compute_data_end(skb); |
| filter_res = BPF_PROG_RUN(prog->filter, skb); |
| } |
| |
| if (prog->exts_integrated) { |
| res->class = 0; |
| res->classid = TC_H_MAJ(prog->res.classid) | |
| qdisc_skb_cb(skb)->tc_classid; |
| |
| ret = cls_bpf_exec_opcode(filter_res); |
| if (ret == TC_ACT_UNSPEC) |
| continue; |
| break; |
| } |
| |
| if (filter_res == 0) |
| continue; |
| if (filter_res != -1) { |
| res->class = 0; |
| res->classid = filter_res; |
| } else { |
| *res = prog->res; |
| } |
| |
| ret = tcf_exts_exec(skb, &prog->exts, res); |
| if (ret < 0) |
| continue; |
| |
| break; |
| } |
| rcu_read_unlock(); |
| |
| return ret; |
| } |
| |
| static bool cls_bpf_is_ebpf(const struct cls_bpf_prog *prog) |
| { |
| return !prog->bpf_ops; |
| } |
| |
| static int cls_bpf_offload_cmd(struct tcf_proto *tp, struct cls_bpf_prog *prog, |
| enum tc_clsbpf_command cmd) |
| { |
| struct net_device *dev = tp->q->dev_queue->dev; |
| struct tc_cls_bpf_offload bpf_offload = {}; |
| struct tc_to_netdev offload; |
| |
| offload.type = TC_SETUP_CLSBPF; |
| offload.cls_bpf = &bpf_offload; |
| |
| bpf_offload.command = cmd; |
| bpf_offload.exts = &prog->exts; |
| bpf_offload.prog = prog->filter; |
| bpf_offload.name = prog->bpf_name; |
| bpf_offload.exts_integrated = prog->exts_integrated; |
| bpf_offload.gen_flags = prog->gen_flags; |
| |
| return dev->netdev_ops->ndo_setup_tc(dev, tp->q->handle, |
| tp->protocol, &offload); |
| } |
| |
| static int cls_bpf_offload(struct tcf_proto *tp, struct cls_bpf_prog *prog, |
| struct cls_bpf_prog *oldprog) |
| { |
| struct net_device *dev = tp->q->dev_queue->dev; |
| struct cls_bpf_prog *obj = prog; |
| enum tc_clsbpf_command cmd; |
| bool skip_sw; |
| int ret; |
| |
| skip_sw = tc_skip_sw(prog->gen_flags) || |
| (oldprog && tc_skip_sw(oldprog->gen_flags)); |
| |
| if (oldprog && oldprog->offloaded) { |
| if (tc_should_offload(dev, tp, prog->gen_flags)) { |
| cmd = TC_CLSBPF_REPLACE; |
| } else if (!tc_skip_sw(prog->gen_flags)) { |
| obj = oldprog; |
| cmd = TC_CLSBPF_DESTROY; |
| } else { |
| return -EINVAL; |
| } |
| } else { |
| if (!tc_should_offload(dev, tp, prog->gen_flags)) |
| return skip_sw ? -EINVAL : 0; |
| cmd = TC_CLSBPF_ADD; |
| } |
| |
| ret = cls_bpf_offload_cmd(tp, obj, cmd); |
| if (ret) |
| return skip_sw ? ret : 0; |
| |
| obj->offloaded = true; |
| if (oldprog) |
| oldprog->offloaded = false; |
| |
| return 0; |
| } |
| |
| static void cls_bpf_stop_offload(struct tcf_proto *tp, |
| struct cls_bpf_prog *prog) |
| { |
| int err; |
| |
| if (!prog->offloaded) |
| return; |
| |
| err = cls_bpf_offload_cmd(tp, prog, TC_CLSBPF_DESTROY); |
| if (err) { |
| pr_err("Stopping hardware offload failed: %d\n", err); |
| return; |
| } |
| |
| prog->offloaded = false; |
| } |
| |
| static void cls_bpf_offload_update_stats(struct tcf_proto *tp, |
| struct cls_bpf_prog *prog) |
| { |
| if (!prog->offloaded) |
| return; |
| |
| cls_bpf_offload_cmd(tp, prog, TC_CLSBPF_STATS); |
| } |
| |
| static int cls_bpf_init(struct tcf_proto *tp) |
| { |
| struct cls_bpf_head *head; |
| |
| head = kzalloc(sizeof(*head), GFP_KERNEL); |
| if (head == NULL) |
| return -ENOBUFS; |
| |
| INIT_LIST_HEAD_RCU(&head->plist); |
| rcu_assign_pointer(tp->root, head); |
| |
| return 0; |
| } |
| |
| static void cls_bpf_delete_prog(struct tcf_proto *tp, struct cls_bpf_prog *prog) |
| { |
| tcf_exts_destroy(&prog->exts); |
| |
| if (cls_bpf_is_ebpf(prog)) |
| bpf_prog_put(prog->filter); |
| else |
| bpf_prog_destroy(prog->filter); |
| |
| kfree(prog->bpf_name); |
| kfree(prog->bpf_ops); |
| kfree(prog); |
| } |
| |
| static void __cls_bpf_delete_prog(struct rcu_head *rcu) |
| { |
| struct cls_bpf_prog *prog = container_of(rcu, struct cls_bpf_prog, rcu); |
| |
| cls_bpf_delete_prog(prog->tp, prog); |
| } |
| |
| static int cls_bpf_delete(struct tcf_proto *tp, unsigned long arg) |
| { |
| struct cls_bpf_prog *prog = (struct cls_bpf_prog *) arg; |
| |
| cls_bpf_stop_offload(tp, prog); |
| list_del_rcu(&prog->link); |
| tcf_unbind_filter(tp, &prog->res); |
| call_rcu(&prog->rcu, __cls_bpf_delete_prog); |
| |
| return 0; |
| } |
| |
| static bool cls_bpf_destroy(struct tcf_proto *tp, bool force) |
| { |
| struct cls_bpf_head *head = rtnl_dereference(tp->root); |
| struct cls_bpf_prog *prog, *tmp; |
| |
| if (!force && !list_empty(&head->plist)) |
| return false; |
| |
| list_for_each_entry_safe(prog, tmp, &head->plist, link) { |
| cls_bpf_stop_offload(tp, prog); |
| list_del_rcu(&prog->link); |
| tcf_unbind_filter(tp, &prog->res); |
| call_rcu(&prog->rcu, __cls_bpf_delete_prog); |
| } |
| |
| RCU_INIT_POINTER(tp->root, NULL); |
| kfree_rcu(head, rcu); |
| return true; |
| } |
| |
| static unsigned long cls_bpf_get(struct tcf_proto *tp, u32 handle) |
| { |
| struct cls_bpf_head *head = rtnl_dereference(tp->root); |
| struct cls_bpf_prog *prog; |
| unsigned long ret = 0UL; |
| |
| if (head == NULL) |
| return 0UL; |
| |
| list_for_each_entry(prog, &head->plist, link) { |
| if (prog->handle == handle) { |
| ret = (unsigned long) prog; |
| break; |
| } |
| } |
| |
| return ret; |
| } |
| |
| static int cls_bpf_prog_from_ops(struct nlattr **tb, struct cls_bpf_prog *prog) |
| { |
| 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_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_BPF_OPS])) |
| return -EINVAL; |
| |
| bpf_ops = kzalloc(bpf_size, GFP_KERNEL); |
| if (bpf_ops == NULL) |
| return -ENOMEM; |
| |
| memcpy(bpf_ops, nla_data(tb[TCA_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; |
| } |
| |
| prog->bpf_ops = bpf_ops; |
| prog->bpf_num_ops = bpf_num_ops; |
| prog->bpf_name = NULL; |
| prog->filter = fp; |
| |
| return 0; |
| } |
| |
| static int cls_bpf_prog_from_efd(struct nlattr **tb, struct cls_bpf_prog *prog, |
| const struct tcf_proto *tp) |
| { |
| struct bpf_prog *fp; |
| char *name = NULL; |
| u32 bpf_fd; |
| |
| bpf_fd = nla_get_u32(tb[TCA_BPF_FD]); |
| |
| fp = bpf_prog_get_type(bpf_fd, BPF_PROG_TYPE_SCHED_CLS); |
| if (IS_ERR(fp)) |
| return PTR_ERR(fp); |
| |
| if (tb[TCA_BPF_NAME]) { |
| name = nla_memdup(tb[TCA_BPF_NAME], GFP_KERNEL); |
| if (!name) { |
| bpf_prog_put(fp); |
| return -ENOMEM; |
| } |
| } |
| |
| prog->bpf_ops = NULL; |
| prog->bpf_fd = bpf_fd; |
| prog->bpf_name = name; |
| prog->filter = fp; |
| |
| if (fp->dst_needed && !(tp->q->flags & TCQ_F_INGRESS)) |
| netif_keep_dst(qdisc_dev(tp->q)); |
| |
| return 0; |
| } |
| |
| static int cls_bpf_modify_existing(struct net *net, struct tcf_proto *tp, |
| struct cls_bpf_prog *prog, |
| unsigned long base, struct nlattr **tb, |
| struct nlattr *est, bool ovr) |
| { |
| bool is_bpf, is_ebpf, have_exts = false; |
| struct tcf_exts exts; |
| u32 gen_flags = 0; |
| int ret; |
| |
| is_bpf = tb[TCA_BPF_OPS_LEN] && tb[TCA_BPF_OPS]; |
| is_ebpf = tb[TCA_BPF_FD]; |
| if ((!is_bpf && !is_ebpf) || (is_bpf && is_ebpf)) |
| return -EINVAL; |
| |
| ret = tcf_exts_init(&exts, TCA_BPF_ACT, TCA_BPF_POLICE); |
| if (ret < 0) |
| return ret; |
| ret = tcf_exts_validate(net, tp, tb, est, &exts, ovr); |
| if (ret < 0) |
| goto errout; |
| |
| if (tb[TCA_BPF_FLAGS]) { |
| u32 bpf_flags = nla_get_u32(tb[TCA_BPF_FLAGS]); |
| |
| if (bpf_flags & ~TCA_BPF_FLAG_ACT_DIRECT) { |
| ret = -EINVAL; |
| goto errout; |
| } |
| |
| have_exts = bpf_flags & TCA_BPF_FLAG_ACT_DIRECT; |
| } |
| if (tb[TCA_BPF_FLAGS_GEN]) { |
| gen_flags = nla_get_u32(tb[TCA_BPF_FLAGS_GEN]); |
| if (gen_flags & ~CLS_BPF_SUPPORTED_GEN_FLAGS || |
| !tc_flags_valid(gen_flags)) { |
| ret = -EINVAL; |
| goto errout; |
| } |
| } |
| |
| prog->exts_integrated = have_exts; |
| prog->gen_flags = gen_flags; |
| |
| ret = is_bpf ? cls_bpf_prog_from_ops(tb, prog) : |
| cls_bpf_prog_from_efd(tb, prog, tp); |
| if (ret < 0) |
| goto errout; |
| |
| if (tb[TCA_BPF_CLASSID]) { |
| prog->res.classid = nla_get_u32(tb[TCA_BPF_CLASSID]); |
| tcf_bind_filter(tp, &prog->res, base); |
| } |
| |
| tcf_exts_change(tp, &prog->exts, &exts); |
| return 0; |
| |
| errout: |
| tcf_exts_destroy(&exts); |
| return ret; |
| } |
| |
| static u32 cls_bpf_grab_new_handle(struct tcf_proto *tp, |
| struct cls_bpf_head *head) |
| { |
| unsigned int i = 0x80000000; |
| u32 handle; |
| |
| do { |
| if (++head->hgen == 0x7FFFFFFF) |
| head->hgen = 1; |
| } while (--i > 0 && cls_bpf_get(tp, head->hgen)); |
| |
| if (unlikely(i == 0)) { |
| pr_err("Insufficient number of handles\n"); |
| handle = 0; |
| } else { |
| handle = head->hgen; |
| } |
| |
| return handle; |
| } |
| |
| static int cls_bpf_change(struct net *net, struct sk_buff *in_skb, |
| struct tcf_proto *tp, unsigned long base, |
| u32 handle, struct nlattr **tca, |
| unsigned long *arg, bool ovr) |
| { |
| struct cls_bpf_head *head = rtnl_dereference(tp->root); |
| struct cls_bpf_prog *oldprog = (struct cls_bpf_prog *) *arg; |
| struct nlattr *tb[TCA_BPF_MAX + 1]; |
| struct cls_bpf_prog *prog; |
| int ret; |
| |
| if (tca[TCA_OPTIONS] == NULL) |
| return -EINVAL; |
| |
| ret = nla_parse_nested(tb, TCA_BPF_MAX, tca[TCA_OPTIONS], bpf_policy); |
| if (ret < 0) |
| return ret; |
| |
| prog = kzalloc(sizeof(*prog), GFP_KERNEL); |
| if (!prog) |
| return -ENOBUFS; |
| |
| ret = tcf_exts_init(&prog->exts, TCA_BPF_ACT, TCA_BPF_POLICE); |
| if (ret < 0) |
| goto errout; |
| |
| if (oldprog) { |
| if (handle && oldprog->handle != handle) { |
| ret = -EINVAL; |
| goto errout; |
| } |
| } |
| |
| if (handle == 0) |
| prog->handle = cls_bpf_grab_new_handle(tp, head); |
| else |
| prog->handle = handle; |
| if (prog->handle == 0) { |
| ret = -EINVAL; |
| goto errout; |
| } |
| |
| ret = cls_bpf_modify_existing(net, tp, prog, base, tb, tca[TCA_RATE], |
| ovr); |
| if (ret < 0) |
| goto errout; |
| |
| ret = cls_bpf_offload(tp, prog, oldprog); |
| if (ret) { |
| cls_bpf_delete_prog(tp, prog); |
| return ret; |
| } |
| |
| if (oldprog) { |
| list_replace_rcu(&oldprog->link, &prog->link); |
| tcf_unbind_filter(tp, &oldprog->res); |
| call_rcu(&oldprog->rcu, __cls_bpf_delete_prog); |
| } else { |
| list_add_rcu(&prog->link, &head->plist); |
| } |
| |
| *arg = (unsigned long) prog; |
| return 0; |
| |
| errout: |
| tcf_exts_destroy(&prog->exts); |
| kfree(prog); |
| return ret; |
| } |
| |
| static int cls_bpf_dump_bpf_info(const struct cls_bpf_prog *prog, |
| struct sk_buff *skb) |
| { |
| struct nlattr *nla; |
| |
| if (nla_put_u16(skb, TCA_BPF_OPS_LEN, prog->bpf_num_ops)) |
| return -EMSGSIZE; |
| |
| nla = nla_reserve(skb, TCA_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 cls_bpf_dump_ebpf_info(const struct cls_bpf_prog *prog, |
| struct sk_buff *skb) |
| { |
| if (nla_put_u32(skb, TCA_BPF_FD, prog->bpf_fd)) |
| return -EMSGSIZE; |
| |
| if (prog->bpf_name && |
| nla_put_string(skb, TCA_BPF_NAME, prog->bpf_name)) |
| return -EMSGSIZE; |
| |
| return 0; |
| } |
| |
| static int cls_bpf_dump(struct net *net, struct tcf_proto *tp, unsigned long fh, |
| struct sk_buff *skb, struct tcmsg *tm) |
| { |
| struct cls_bpf_prog *prog = (struct cls_bpf_prog *) fh; |
| struct nlattr *nest; |
| u32 bpf_flags = 0; |
| int ret; |
| |
| if (prog == NULL) |
| return skb->len; |
| |
| tm->tcm_handle = prog->handle; |
| |
| cls_bpf_offload_update_stats(tp, prog); |
| |
| nest = nla_nest_start(skb, TCA_OPTIONS); |
| if (nest == NULL) |
| goto nla_put_failure; |
| |
| if (prog->res.classid && |
| nla_put_u32(skb, TCA_BPF_CLASSID, prog->res.classid)) |
| goto nla_put_failure; |
| |
| if (cls_bpf_is_ebpf(prog)) |
| ret = cls_bpf_dump_ebpf_info(prog, skb); |
| else |
| ret = cls_bpf_dump_bpf_info(prog, skb); |
| if (ret) |
| goto nla_put_failure; |
| |
| if (tcf_exts_dump(skb, &prog->exts) < 0) |
| goto nla_put_failure; |
| |
| if (prog->exts_integrated) |
| bpf_flags |= TCA_BPF_FLAG_ACT_DIRECT; |
| if (bpf_flags && nla_put_u32(skb, TCA_BPF_FLAGS, bpf_flags)) |
| goto nla_put_failure; |
| if (prog->gen_flags && |
| nla_put_u32(skb, TCA_BPF_FLAGS_GEN, prog->gen_flags)) |
| goto nla_put_failure; |
| |
| nla_nest_end(skb, nest); |
| |
| if (tcf_exts_dump_stats(skb, &prog->exts) < 0) |
| goto nla_put_failure; |
| |
| return skb->len; |
| |
| nla_put_failure: |
| nla_nest_cancel(skb, nest); |
| return -1; |
| } |
| |
| static void cls_bpf_walk(struct tcf_proto *tp, struct tcf_walker *arg) |
| { |
| struct cls_bpf_head *head = rtnl_dereference(tp->root); |
| struct cls_bpf_prog *prog; |
| |
| list_for_each_entry(prog, &head->plist, link) { |
| if (arg->count < arg->skip) |
| goto skip; |
| if (arg->fn(tp, (unsigned long) prog, arg) < 0) { |
| arg->stop = 1; |
| break; |
| } |
| skip: |
| arg->count++; |
| } |
| } |
| |
| static struct tcf_proto_ops cls_bpf_ops __read_mostly = { |
| .kind = "bpf", |
| .owner = THIS_MODULE, |
| .classify = cls_bpf_classify, |
| .init = cls_bpf_init, |
| .destroy = cls_bpf_destroy, |
| .get = cls_bpf_get, |
| .change = cls_bpf_change, |
| .delete = cls_bpf_delete, |
| .walk = cls_bpf_walk, |
| .dump = cls_bpf_dump, |
| }; |
| |
| static int __init cls_bpf_init_mod(void) |
| { |
| return register_tcf_proto_ops(&cls_bpf_ops); |
| } |
| |
| static void __exit cls_bpf_exit_mod(void) |
| { |
| unregister_tcf_proto_ops(&cls_bpf_ops); |
| } |
| |
| module_init(cls_bpf_init_mod); |
| module_exit(cls_bpf_exit_mod); |