cregit-Linux how code gets into the kernel

Release 4.11 net/sched/cls_bpf.c

Directory: net/sched
/*
 * 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;
	
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; } }

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Daniel Borkmann3491.89%150.00%
Alexei Starovoitov38.11%150.00%
Total37100.00%2100.00%


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; }

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Daniel Borkmann19268.57%545.45%
Alexei Starovoitov6222.14%327.27%
Jakub Kiciński227.86%19.09%
John Fastabend31.07%19.09%
Américo Wang10.36%19.09%
Total280100.00%11100.00%


static bool cls_bpf_is_ebpf(const struct cls_bpf_prog *prog) { return !prog->bpf_ops; }

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Daniel Borkmann18100.00%1100.00%
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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; int err; 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; err = dev->netdev_ops->ndo_setup_tc(dev, tp->q->handle, tp->protocol, &offload); if (!err && (cmd == TC_CLSBPF_ADD || cmd == TC_CLSBPF_REPLACE)) prog->gen_flags |= TCA_CLS_FLAGS_IN_HW; return err; }

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Jakub Kiciński12581.17%266.67%
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Total154100.00%3100.00%


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; }

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Jakub Kiciński198100.00%3100.00%
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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; }

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Jakub Kiciński58100.00%1100.00%
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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); }

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Jakub Kiciński33100.00%1100.00%
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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; }

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Daniel Borkmann5491.53%150.00%
John Fastabend58.47%150.00%
Total59100.00%2100.00%


static void __cls_bpf_delete_prog(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); }

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Daniel Borkmann5998.33%375.00%
Alexei Starovoitov11.67%125.00%
Total60100.00%4100.00%


static void cls_bpf_delete_prog_rcu(struct rcu_head *rcu) { __cls_bpf_delete_prog(container_of(rcu, struct cls_bpf_prog, rcu)); }

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John Fastabend2187.50%150.00%
Daniel Borkmann312.50%150.00%
Total24100.00%2100.00%


static void __cls_bpf_delete(struct tcf_proto *tp, struct cls_bpf_prog *prog) { 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); }

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Daniel Borkmann2854.90%240.00%
John Fastabend1631.37%240.00%
Jakub Kiciński713.73%120.00%
Total51100.00%5100.00%


static int cls_bpf_delete(struct tcf_proto *tp, unsigned long arg) { __cls_bpf_delete(tp, (struct cls_bpf_prog *) arg); return 0; }

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Daniel Borkmann30100.00%2100.00%
Total30100.00%2100.00%


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_delete(tp, prog); kfree_rcu(head, rcu); return true; }

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Daniel Borkmann4253.85%240.00%
Cong Wang2430.77%120.00%
John Fastabend67.69%120.00%
Jakub Kiciński67.69%120.00%
Total78100.00%5100.00%


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; list_for_each_entry(prog, &head->plist, link) { if (prog->handle == handle) { ret = (unsigned long) prog; break; } } return ret; }

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Daniel Borkmann6694.29%133.33%
John Fastabend34.29%133.33%
Jiri Pirko11.43%133.33%
Total70100.00%3100.00%


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; }

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Daniel Borkmann18195.77%466.67%
Jiri Pirko63.17%116.67%
Alexei Starovoitov21.06%116.67%
Total189100.00%6100.00%


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_name = name; prog->filter = fp; if (fp->dst_needed && !(tp->q->flags & TCQ_F_INGRESS)) netif_keep_dst(qdisc_dev(tp->q)); return 0; }

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Daniel Borkmann15399.35%583.33%
Thomas Graf10.65%116.67%
Total154100.00%6100.00%


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; }

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Daniel Borkmann24874.03%571.43%
Jakub Kiciński5315.82%114.29%
Américo Wang3410.15%114.29%
Total335100.00%7100.00%


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; }

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Daniel Borkmann92100.00%2100.00%
Total92100.00%2100.00%


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(prog); return ret; } if (!tc_in_hw(prog->gen_flags)) prog->gen_flags |= TCA_CLS_FLAGS_NOT_IN_HW; if (oldprog) { list_replace_rcu(&oldprog->link, &prog->link); tcf_unbind_filter(tp, &oldprog->res); call_rcu(&oldprog->rcu, cls_bpf_delete_prog_rcu); } else { list_add_rcu(&prog->link, &head->plist); } *arg = (unsigned long) prog; return 0; errout: tcf_exts_destroy(&prog->exts); kfree(prog); return ret; }

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Daniel Borkmann24462.09%325.00%
John Fastabend7318.58%216.67%
Américo Wang317.89%325.00%
Jakub Kiciński246.11%216.67%
Or Gerlitz164.07%18.33%
Cong Wang51.27%18.33%
Total393100.00%12100.00%


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; }

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Daniel Borkmann88100.00%1100.00%
Total88100.00%1100.00%


static int cls_bpf_dump_ebpf_info(const struct cls_bpf_prog *prog, struct sk_buff *skb) { struct nlattr *nla; if (prog->bpf_name && nla_put_string(skb, TCA_BPF_NAME, prog->bpf_name)) return -EMSGSIZE; nla = nla_reserve(skb, TCA_BPF_TAG, sizeof(prog->filter->tag)); if (nla == NULL) return -EMSGSIZE; memcpy(nla_data(nla), prog->filter->tag, nla_len(nla)); return 0; }

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Daniel Borkmann93100.00%3100.00%
Total93100.00%3100.00%


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; }

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Daniel Borkmann22987.74%457.14%
Jakub Kiciński2710.34%228.57%
Américo Wang51.92%114.29%
Total261100.00%7100.00%


static