Initial import

1 files changed, 495 insertions, 0 deletions

diff --git a/net/sched/cls_bpf.c b/net/sched/cls_bpf.c
new file mode 100644
index 000000000..91bd9c194
--- /dev/null
+++ b/net/sched/cls_bpf.c
@@ -0,0 +1,495 @@
+/*
+ * 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
+
+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;
+	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_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_classify(struct sk_buff *skb, const struct tcf_proto *tp,
+			    struct tcf_result *res)
+{
+	struct cls_bpf_head *head = rcu_dereference_bh(tp->root);
+	struct cls_bpf_prog *prog;
+	int ret = -1;
+
+	if (unlikely(!skb_mac_header_was_set(skb)))
+		return -1;
+
+	/* Needed here for accessing maps. */
+	rcu_read_lock();
+	list_for_each_entry_rcu(prog, &head->plist, link) {
+		int filter_res = BPF_PROG_RUN(prog->filter, skb);
+
+		if (filter_res == 0)
+			continue;
+
+		*res = prog->res;
+		if (filter_res != -1)
+			res->classid = filter_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_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;
+
+	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) {
+		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, u32 classid)
+{
+	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;
+	prog->res.classid = classid;
+
+	return 0;
+}
+
+static int cls_bpf_prog_from_efd(struct nlattr **tb,
+				 struct cls_bpf_prog *prog, u32 classid)
+{
+	struct bpf_prog *fp;
+	char *name = NULL;
+	u32 bpf_fd;
+
+	bpf_fd = nla_get_u32(tb[TCA_BPF_FD]);
+
+	fp = bpf_prog_get(bpf_fd);
+	if (IS_ERR(fp))
+		return PTR_ERR(fp);
+
+	if (fp->type != BPF_PROG_TYPE_SCHED_CLS) {
+		bpf_prog_put(fp);
+		return -EINVAL;
+	}
+
+	if (tb[TCA_BPF_NAME]) {
+		name = kmemdup(nla_data(tb[TCA_BPF_NAME]),
+			       nla_len(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;
+	prog->res.classid = classid;
+
+	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)
+{
+	struct tcf_exts exts;
+	bool is_bpf, is_ebpf;
+	u32 classid;
+	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) ||
+	    !tb[TCA_BPF_CLASSID])
+		return -EINVAL;
+
+	tcf_exts_init(&exts, TCA_BPF_ACT, TCA_BPF_POLICE);
+	ret = tcf_exts_validate(net, tp, tb, est, &exts, ovr);
+	if (ret < 0)
+		return ret;
+
+	classid = nla_get_u32(tb[TCA_BPF_CLASSID]);
+
+	ret = is_bpf ? cls_bpf_prog_from_ops(tb, prog, classid) :
+		       cls_bpf_prog_from_efd(tb, prog, classid);
+	if (ret < 0) {
+		tcf_exts_destroy(&exts);
+		return ret;
+	}
+
+	tcf_bind_filter(tp, &prog->res, base);
+	tcf_exts_change(tp, &prog->exts, &exts);
+
+	return 0;
+}
+
+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;
+
+	tcf_exts_init(&prog->exts, TCA_BPF_ACT, TCA_BPF_POLICE);
+
+	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;
+
+	if (oldprog) {
+		list_replace_rcu(&prog->link, &oldprog->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:
+	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;
+	int ret;
+
+	if (prog == NULL)
+		return skb->len;
+
+	tm->tcm_handle = prog->handle;
+
+	nest = nla_nest_start(skb, TCA_OPTIONS);
+	if (nest == NULL)
+		goto nla_put_failure;
+
+	if (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;
+
+	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);