@@ -723,6 +723,25 @@ enum {
#define TCA_MATCHALL_MAX (__TCA_MATCHALL_MAX - 1)
+/* P4 classifier */
+
+enum {
+ TCA_P4_UNSPEC,
+ TCA_P4_CLASSID,
+ TCA_P4_ACT,
+ TCA_P4_PNAME,
+ TCA_P4_PIPEID,
+ TCA_P4_PROG_FD,
+ TCA_P4_PROG_NAME,
+ TCA_P4_PROG_TYPE,
+ TCA_P4_PROG_COOKIE,
+ TCA_P4_PROG_ID,
+ TCA_P4_PAD,
+ __TCA_P4_MAX,
+};
+
+#define TCA_P4_MAX (__TCA_P4_MAX - 1)
+
/* Extended Matches */
struct tcf_ematch_tree_hdr {
@@ -566,6 +566,18 @@ config NET_CLS_MATCHALL
To compile this code as a module, choose M here: the module will
be called cls_matchall.
+config NET_CLS_P4
+ tristate "P4 classifier"
+ select NET_CLS
+ select NET_P4_TC
+ help
+ If you say Y here, you will be able to bind a P4 pipeline
+ program. You will need to install P4 templates scripts successfully to
+ use this feature.
+
+ To compile this code as a module, choose M here: the module will
+ be called cls_p4.
+
config NET_EMATCH
bool "Extended Matches"
select NET_CLS
@@ -73,6 +73,7 @@ obj-$(CONFIG_NET_CLS_CGROUP) += cls_cgroup.o
obj-$(CONFIG_NET_CLS_BPF) += cls_bpf.o
obj-$(CONFIG_NET_CLS_FLOWER) += cls_flower.o
obj-$(CONFIG_NET_CLS_MATCHALL) += cls_matchall.o
+obj-$(CONFIG_NET_CLS_P4) += cls_p4.o
obj-$(CONFIG_NET_EMATCH) += ematch.o
obj-$(CONFIG_NET_EMATCH_CMP) += em_cmp.o
obj-$(CONFIG_NET_EMATCH_NBYTE) += em_nbyte.o
new file mode 100644
@@ -0,0 +1,508 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * net/sched/cls_p4.c - P4 Classifier
+ * Copyright (c) 2022-2023, Mojatatu Networks
+ * Copyright (c) 2022-2023, Intel Corporation.
+ * Authors: Jamal Hadi Salim <jhs@mojatatu.com>
+ * Victor Nogueira <victor@mojatatu.com>
+ * Pedro Tammela <pctammela@mojatatu.com>
+ */
+
+#include <linux/kernel.h>
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/percpu.h>
+#include <linux/bpf.h>
+#include <linux/filter.h>
+
+#include <net/sch_generic.h>
+#include <net/pkt_cls.h>
+
+#include <net/p4tc.h>
+
+#include "p4tc/trace.h"
+
+#define CLS_P4_PROG_NAME_LEN 256
+
+struct p4tc_bpf_prog {
+ struct bpf_prog *p4_prog;
+ const char *p4_prog_name;
+};
+
+struct cls_p4_head {
+ struct tcf_exts exts;
+ struct tcf_result res;
+ struct rcu_work rwork;
+ struct p4tc_pipeline *pipeline;
+ struct p4tc_bpf_prog *prog;
+ u32 p4_prog_cookie;
+ u32 handle;
+};
+
+static int p4_classify(struct sk_buff *skb, const struct tcf_proto *tp,
+ struct tcf_result *res)
+{
+ struct cls_p4_head *head = rcu_dereference_bh(tp->root);
+ bool at_ingress = skb_at_tc_ingress(skb);
+ int rc = TC_ACT_PIPE;
+
+ if (unlikely(!head)) {
+ pr_err("P4 classifier not found\n");
+ return -1;
+ }
+
+ /* head->prog represents the eBPF program that will be first executed by
+ * the data plane. It may or may not exist. In addition to head->prog,
+ * we'll have another eBPF program that will execute after this one in
+ * the form of a filter action (head->exts).
+ * head->prog->p4_prog_type == BPf_PROG_TYPE_SCHED_ACT means this
+ * program executes in TC P4 filter.
+ * head->prog->p4_prog_type == BPf_PROG_TYPE_SCHED_XDP means this
+ * program was loaded in XDP and the filter just needs to verify it ran.
+ */
+ if (head->prog) {
+ /* If eBPF program is loaded into TC */
+ if (head->prog->p4_prog->type == BPF_PROG_TYPE_SCHED_ACT) {
+ if (at_ingress) {
+ /* It is safe to push/pull even if skb_shared() */
+ __skb_push(skb, skb->mac_len);
+ bpf_compute_data_pointers(skb);
+ rc = bpf_prog_run(head->prog->p4_prog,
+ skb);
+ __skb_pull(skb, skb->mac_len);
+ } else {
+ bpf_compute_data_pointers(skb);
+ rc = bpf_prog_run(head->prog->p4_prog,
+ skb);
+ }
+ /* Potentially eBPF program was executed before at XDP and we
+ * need to check the cookie to see if that was the case.
+ */
+ } else {
+ struct bpf_skb_data_end *cb;
+ u32 *cookie;
+
+ if (!skb_metadata_len(skb))
+ return TC_ACT_SHOT;
+
+ if (at_ingress)
+ __skb_push(skb, skb->mac_len);
+
+ bpf_compute_data_pointers(skb);
+ cb = (struct bpf_skb_data_end *)skb->cb;
+
+ cookie = (u32 *)(cb->data_meta);
+ if (head->p4_prog_cookie != *cookie) {
+ net_notice_ratelimited("prog_cookie doesn't match");
+ return TC_ACT_SHOT;
+ }
+ }
+ }
+
+ trace_p4_classify(skb, head->pipeline);
+
+ *res = head->res;
+
+ return tcf_exts_exec(skb, &head->exts, res);
+}
+
+static int p4_init(struct tcf_proto *tp)
+{
+ return 0;
+}
+
+static void p4_bpf_prog_destroy(struct p4tc_bpf_prog *prog)
+{
+ bpf_prog_put(prog->p4_prog);
+ kfree(prog->p4_prog_name);
+ kfree(prog);
+}
+
+static void __p4_destroy(struct cls_p4_head *head)
+{
+ tcf_exts_destroy(&head->exts);
+ tcf_exts_put_net(&head->exts);
+ if (head->prog)
+ p4_bpf_prog_destroy(head->prog);
+ tcf_pipeline_put(head->pipeline);
+ kfree(head);
+}
+
+static void p4_destroy_work(struct work_struct *work)
+{
+ struct cls_p4_head *head =
+ container_of(to_rcu_work(work), struct cls_p4_head, rwork);
+
+ rtnl_lock();
+ __p4_destroy(head);
+ rtnl_unlock();
+}
+
+static void p4_destroy(struct tcf_proto *tp, bool rtnl_held,
+ struct netlink_ext_ack *extack)
+{
+ struct cls_p4_head *head = rtnl_dereference(tp->root);
+
+ if (!head)
+ return;
+
+ tcf_unbind_filter(tp, &head->res);
+
+ if (tcf_exts_get_net(&head->exts))
+ tcf_queue_work(&head->rwork, p4_destroy_work);
+ else
+ __p4_destroy(head);
+}
+
+static void *p4_get(struct tcf_proto *tp, u32 handle)
+{
+ struct cls_p4_head *head = rtnl_dereference(tp->root);
+
+ if (head && head->handle == handle)
+ return head;
+
+ return NULL;
+}
+
+static const struct nla_policy p4_policy[TCA_P4_MAX + 1] = {
+ [TCA_P4_UNSPEC] = { .type = NLA_UNSPEC },
+ [TCA_P4_CLASSID] = { .type = NLA_U32 },
+ [TCA_P4_ACT] = { .type = NLA_NESTED },
+ [TCA_P4_PNAME] = { .type = NLA_STRING, .len = PIPELINENAMSIZ },
+ [TCA_P4_PIPEID] = { .type = NLA_U32 },
+ [TCA_P4_PROG_FD] = { .type = NLA_U32 },
+ [TCA_P4_PROG_NAME] = { .type = NLA_STRING,
+ .len = CLS_P4_PROG_NAME_LEN },
+ [TCA_P4_PROG_TYPE] = { .type = NLA_U32 },
+ [TCA_P4_PROG_COOKIE] = { .type = NLA_U32 }
+};
+
+static int cls_p4_prog_from_efd(struct nlattr **tb,
+ struct p4tc_bpf_prog *prog, u32 flags,
+ struct netlink_ext_ack *extack)
+{
+ struct bpf_prog *fp;
+ u32 prog_type;
+ bool skip_sw;
+ char *name;
+ u32 bpf_fd;
+
+ bpf_fd = nla_get_u32(tb[TCA_P4_PROG_FD]);
+ prog_type = nla_get_u32(tb[TCA_P4_PROG_TYPE]);
+ skip_sw = flags & TCA_CLS_FLAGS_SKIP_SW;
+
+ if (prog_type != BPF_PROG_TYPE_XDP &&
+ prog_type != BPF_PROG_TYPE_SCHED_ACT) {
+ NL_SET_ERR_MSG(extack,
+ "BPF prog type must be BPF_PROG_TYPE_SCHED_ACT or BPF_PROG_TYPE_XDP");
+ return -EINVAL;
+ }
+
+ fp = bpf_prog_get_type_dev(bpf_fd, prog_type, skip_sw);
+ if (IS_ERR(fp))
+ return PTR_ERR(fp);
+
+ name = nla_memdup(tb[TCA_P4_PROG_NAME], GFP_KERNEL);
+ if (!name) {
+ bpf_prog_put(fp);
+ return -ENOMEM;
+ }
+
+ prog->p4_prog_name = name;
+ prog->p4_prog = fp;
+
+ return 0;
+}
+
+static int p4_set_parms(struct net *net, struct tcf_proto *tp,
+ struct cls_p4_head *head, unsigned long base,
+ struct nlattr **tb, struct nlattr *est, u32 flags,
+ struct netlink_ext_ack *extack)
+{
+ bool load_bpf_prog = tb[TCA_P4_PROG_NAME] && tb[TCA_P4_PROG_FD] &&
+ tb[TCA_P4_PROG_TYPE];
+ struct p4tc_bpf_prog *prog = NULL;
+ int err;
+
+ err = tcf_exts_validate_ex(net, tp, tb, est, &head->exts, flags, 0,
+ extack);
+ if (err < 0)
+ return err;
+
+ if (load_bpf_prog) {
+ prog = kzalloc(sizeof(*prog), GFP_KERNEL);
+ if (!prog) {
+ err = -ENOMEM;
+ goto exts_destroy;
+ }
+
+ err = cls_p4_prog_from_efd(tb, prog, flags, extack);
+ if (err < 0) {
+ kfree(prog);
+ goto exts_destroy;
+ }
+ }
+
+ if (tb[TCA_P4_PROG_COOKIE]) {
+ struct p4tc_bpf_prog *prog_aux = prog ?: head->prog;
+ u32 *p4_prog_cookie;
+
+ if (!prog_aux) {
+ err = -EINVAL;
+ NL_SET_ERR_MSG(extack,
+ "Must have a BPF program to specify xdp prog_cookie");
+ goto prog_put;
+ }
+
+ if (prog_aux->p4_prog->type != BPF_PROG_TYPE_XDP) {
+ err = -EINVAL;
+ NL_SET_ERR_MSG(extack,
+ "Program must be attached to XDP to specify prog_cookie");
+ goto prog_put;
+ }
+
+ p4_prog_cookie = nla_data(tb[TCA_P4_PROG_COOKIE]);
+ head->p4_prog_cookie = *p4_prog_cookie;
+ } else {
+ struct p4tc_bpf_prog *prog_aux = prog ?: head->prog;
+
+ if (prog_aux && prog_aux->p4_prog->type == BPF_PROG_TYPE_XDP &&
+ !head->p4_prog_cookie) {
+ NL_SET_ERR_MSG(extack,
+ "MUST provide prog_cookie when loading into XDP");
+ err = -EINVAL;
+ goto prog_put;
+ }
+ }
+
+ if (tb[TCA_P4_CLASSID]) {
+ head->res.classid = nla_get_u32(tb[TCA_P4_CLASSID]);
+ tcf_bind_filter(tp, &head->res, base);
+ }
+
+ if (load_bpf_prog) {
+ if (head->prog) {
+ pr_notice("cls_p4: Substituting old BPF program with id %u with new one with id %u\n",
+ head->prog->p4_prog->aux->id, prog->p4_prog->aux->id);
+ p4_bpf_prog_destroy(head->prog);
+ }
+ head->prog = prog;
+ }
+
+ return 0;
+
+prog_put:
+ if (prog)
+ p4_bpf_prog_destroy(prog);
+exts_destroy:
+ tcf_exts_destroy(&head->exts);
+ return err;
+}
+
+static int p4_change(struct net *net, struct sk_buff *in_skb,
+ struct tcf_proto *tp, unsigned long base, u32 handle,
+ struct nlattr **tca, void **arg, u32 flags,
+ struct netlink_ext_ack *extack)
+{
+ struct cls_p4_head *head = rtnl_dereference(tp->root);
+ struct p4tc_pipeline *pipeline = NULL;
+ struct nlattr *tb[TCA_P4_MAX + 1];
+ struct cls_p4_head *new;
+ char *pname = NULL;
+ u32 pipeid = 0;
+ int err;
+
+ if (!tca[TCA_OPTIONS]) {
+ NL_SET_ERR_MSG(extack, "Must provide pipeline options");
+ return -EINVAL;
+ }
+
+ if (head)
+ return -EEXIST;
+
+ err = nla_parse_nested(tb, TCA_P4_MAX, tca[TCA_OPTIONS], p4_policy,
+ extack);
+ if (err < 0)
+ return err;
+
+ if (tb[TCA_P4_PNAME])
+ pname = nla_data(tb[TCA_P4_PNAME]);
+
+ if (tb[TCA_P4_PIPEID])
+ pipeid = nla_get_u32(tb[TCA_P4_PIPEID]);
+
+ pipeline = tcf_pipeline_find_get(net, pname, pipeid, extack);
+ if (IS_ERR(pipeline))
+ return PTR_ERR(pipeline);
+
+ if (!pipeline_sealed(pipeline)) {
+ err = -EINVAL;
+ NL_SET_ERR_MSG(extack, "Pipeline must be sealed before use");
+ goto pipeline_put;
+ }
+
+ new = kzalloc(sizeof(*new), GFP_KERNEL);
+ if (!new) {
+ err = -ENOMEM;
+ goto pipeline_put;
+ }
+
+ err = tcf_exts_init(&new->exts, net, TCA_P4_ACT, 0);
+ if (err)
+ goto err_exts_init;
+
+ if (!handle)
+ handle = 1;
+
+ new->handle = handle;
+
+ err = p4_set_parms(net, tp, new, base, tb, tca[TCA_RATE], flags,
+ extack);
+ if (err)
+ goto err_set_parms;
+
+ new->pipeline = pipeline;
+ *arg = head;
+ rcu_assign_pointer(tp->root, new);
+ return 0;
+
+err_set_parms:
+ tcf_exts_destroy(&new->exts);
+err_exts_init:
+ kfree(new);
+pipeline_put:
+ tcf_pipeline_put(pipeline);
+ return err;
+}
+
+static int p4_delete(struct tcf_proto *tp, void *arg, bool *last,
+ bool rtnl_held, struct netlink_ext_ack *extack)
+{
+ *last = true;
+ return 0;
+}
+
+static void p4_walk(struct tcf_proto *tp, struct tcf_walker *arg,
+ bool rtnl_held)
+{
+ struct cls_p4_head *head = rtnl_dereference(tp->root);
+
+ if (arg->count < arg->skip)
+ goto skip;
+
+ if (!head)
+ return;
+ if (arg->fn(tp, head, arg) < 0)
+ arg->stop = 1;
+skip:
+ arg->count++;
+}
+
+static int p4_prog_dump(struct sk_buff *skb, struct p4tc_bpf_prog *prog,
+ u32 prog_cookie)
+{
+ unsigned char *b = nlmsg_get_pos(skb);
+
+ if (nla_put_u32(skb, TCA_P4_PROG_ID, prog->p4_prog->aux->id))
+ goto nla_put_failure;
+
+ if (nla_put_string(skb, TCA_P4_PROG_NAME, prog->p4_prog_name))
+ goto nla_put_failure;
+
+ if (nla_put_u32(skb, TCA_P4_PROG_TYPE, prog->p4_prog->type))
+ goto nla_put_failure;
+
+ if (prog_cookie &&
+ nla_put_u32(skb, TCA_P4_PROG_COOKIE, prog_cookie))
+ goto nla_put_failure;
+
+ return 0;
+
+nla_put_failure:
+ nlmsg_trim(skb, b);
+ return -1;
+}
+
+static int p4_dump(struct net *net, struct tcf_proto *tp, void *fh,
+ struct sk_buff *skb, struct tcmsg *t, bool rtnl_held)
+{
+ struct cls_p4_head *head = fh;
+ struct nlattr *nest;
+
+ if (!head)
+ return skb->len;
+
+ t->tcm_handle = head->handle;
+
+ nest = nla_nest_start(skb, TCA_OPTIONS);
+ if (!nest)
+ goto nla_put_failure;
+
+ if (nla_put_string(skb, TCA_P4_PNAME, head->pipeline->common.name))
+ goto nla_put_failure;
+
+ if (head->res.classid &&
+ nla_put_u32(skb, TCA_P4_CLASSID, head->res.classid))
+ goto nla_put_failure;
+
+ if (head->prog && p4_prog_dump(skb, head->prog, head->p4_prog_cookie))
+ goto nla_put_failure;
+
+ if (tcf_exts_dump(skb, &head->exts))
+ goto nla_put_failure;
+
+ nla_nest_end(skb, nest);
+
+ if (tcf_exts_dump_stats(skb, &head->exts) < 0)
+ goto nla_put_failure;
+
+ return skb->len;
+
+nla_put_failure:
+ nla_nest_cancel(skb, nest);
+ return -1;
+}
+
+static void p4_bind_class(void *fh, u32 classid, unsigned long cl, void *q,
+ unsigned long base)
+{
+ struct cls_p4_head *head = fh;
+
+ if (head && head->res.classid == classid) {
+ if (cl)
+ __tcf_bind_filter(q, &head->res, base);
+ else
+ __tcf_unbind_filter(q, &head->res);
+ }
+}
+
+static struct tcf_proto_ops cls_p4_ops __read_mostly = {
+ .kind = "p4",
+ .classify = p4_classify,
+ .init = p4_init,
+ .destroy = p4_destroy,
+ .get = p4_get,
+ .change = p4_change,
+ .delete = p4_delete,
+ .walk = p4_walk,
+ .dump = p4_dump,
+ .bind_class = p4_bind_class,
+ .owner = THIS_MODULE,
+};
+
+static int __init cls_p4_init(void)
+{
+ return register_tcf_proto_ops(&cls_p4_ops);
+}
+
+static void __exit cls_p4_exit(void)
+{
+ unregister_tcf_proto_ops(&cls_p4_ops);
+}
+
+module_init(cls_p4_init);
+module_exit(cls_p4_exit);
+
+MODULE_AUTHOR("Mojatatu Networks");
+MODULE_DESCRIPTION("P4 Classifier");
+MODULE_LICENSE("GPL");
@@ -1,5 +1,7 @@
# SPDX-License-Identifier: GPL-2.0
+CFLAGS_trace.o := -I$(src)
+
obj-y := p4tc_types.o p4tc_pipeline.o p4tc_tmpl_api.o \
p4tc_parser_api.o p4tc_hdrfield.o p4tc_action.o p4tc_table.o \
- p4tc_tbl_entry.o p4tc_runtime_api.o p4tc_bpf.o
+ p4tc_tbl_entry.o p4tc_runtime_api.o p4tc_bpf.o trace.o
new file mode 100644
@@ -0,0 +1,10 @@
+// SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+
+#include <net/p4tc.h>
+
+#ifndef __CHECKER__
+
+#define CREATE_TRACE_POINTS
+#include "trace.h"
+EXPORT_TRACEPOINT_SYMBOL_GPL(p4_classify);
+#endif
new file mode 100644
@@ -0,0 +1,44 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#undef TRACE_SYSTEM
+#define TRACE_SYSTEM p4tc
+
+#if !defined(__P4TC_TRACE_H_) || defined(TRACE_HEADER_MULTI_READ)
+#define __P4TC_TRACE_H
+
+#include <linux/tracepoint.h>
+
+struct p4tc_pipeline;
+
+TRACE_EVENT(p4_classify,
+ TP_PROTO(struct sk_buff *skb, struct p4tc_pipeline *pipeline),
+
+ TP_ARGS(skb, pipeline),
+
+ TP_STRUCT__entry(__string(pname, pipeline->common.name)
+ __field(u32, p_id)
+ __field(u32, ifindex)
+ __field(u32, ingress)
+ ),
+
+ TP_fast_assign(__assign_str(pname, pipeline->common.name);
+ __entry->p_id = pipeline->common.p_id;
+ __entry->ifindex = skb->dev->ifindex;
+ __entry->ingress = skb_at_tc_ingress(skb);
+ ),
+
+ TP_printk("dev=%u dir=%s pipeline=%s p_id=%u",
+ __entry->ifindex,
+ __entry->ingress ? "ingress" : "egress",
+ __get_str(pname),
+ __entry->p_id
+ )
+);
+
+#endif
+
+#undef TRACE_INCLUDE_PATH
+#define TRACE_INCLUDE_PATH .
+#undef TRACE_INCLUDE_FILE
+#define TRACE_INCLUDE_FILE trace
+
+#include <trace/define_trace.h>
Introduce P4 tc classifier. A tc filter instantiated on this classifier is used to bind a P4 pipeline to one or more netdev ports. To use P4 classifier you must specify a pipeline name that will be associated to this filter. That pipeline must have already been created via a template. For example, if we were to add a filter to ingress of network interface device eth0 and associate it to P4 pipeline simple_l3 we'd issue the following command: tc filter add dev lo parent ffff: protocol any prio 6 p4 pname simple_l3 The filter itself has the following steps: ================================1 PARSING================================ The parser is implemented in ebpf residing either at the TC or XDP level. Note: the different headers and their IDs are already described in the templating definition and the generated ebpf code. The parser could be a separate progman or integrated into the ebpf program. For example, when we have a separate parser program which is loaded into XDP, we first need to load it into XDP using with the ip command: ip link set $P0 xdp obj $PROGNAME.o section parser/xdp verbose Then we pin it: bpftool prog pin id $ID pin /tmp/ After that we create the P4 filter and reference the XDP program: $TC filter add dev $P0 ingress protocol ip prio 1 p4 pname redirect_srcip \ prog xdp pinned /tmp/xdp_parser prog_cookie 22 Note that we also specify a the "prog_cookie", which is used to verify whether the eBPF program has executed or not before we reach the P4 classifier. The eBPF program sets this cookie by using the kfunc bpf_p4tc_set_cookie. =============================FILTER ACTIONS============================= Filter actions will be where the eBPF program that implements the remaining P4 program components, aside from the parser, will reside in the form of a TC BPF action. Of course, the user can choose to not specify a separate eBPF program as a parser and simply implement all the P4 program components in one eBPF program, which will be the filter action. The filter will return the op code returned by this action. Co-developed-by: Victor Nogueira <victor@mojatatu.com> Signed-off-by: Victor Nogueira <victor@mojatatu.com> Co-developed-by: Pedro Tammela <pctammela@mojatatu.com> Signed-off-by: Pedro Tammela <pctammela@mojatatu.com> Signed-off-by: Jamal Hadi Salim <jhs@mojatatu.com> --- include/uapi/linux/pkt_cls.h | 19 ++ net/sched/Kconfig | 12 + net/sched/Makefile | 1 + net/sched/cls_p4.c | 508 +++++++++++++++++++++++++++++++++++ net/sched/p4tc/Makefile | 4 +- net/sched/p4tc/trace.c | 10 + net/sched/p4tc/trace.h | 44 +++ 7 files changed, 597 insertions(+), 1 deletion(-) create mode 100644 net/sched/cls_p4.c create mode 100644 net/sched/p4tc/trace.c create mode 100644 net/sched/p4tc/trace.h