Skip to content

Commit

Permalink
p4tc: add set of P4TC table lookup kfuncs
Browse files Browse the repository at this point in the history 
We add an initial set of kfuncs to allow table lookups from eBPF programs.

- bpf_skb_p4tc_tbl_lookup: Used to lookup a table entry from a BPF
program installed in TC. To find the table entry we take in an skb, the
pipeline ID, the table ID, a key and a key size.
We use the skb to get the network namespace structure where all the
pipelines are stored. After that we use the pipeline ID and the table
ID, to find the table. We then use the key to search for the entry.
We return an entry on success and NULL on failure.

- bpf_xdp_p4tc_tbl_lookup: Used to lookup a table entry from a BPF
program installed in XDP. To find the table entry we take in an skb, the
pipeline ID, the table ID, a key and a key size.
We use struct xdp_md to get the network namespace structure where all
the pipelines are stored. After that we use the pipeline ID and the table
ID, to find the table. We then use the key to search for the entry.
We return an entry on success and NULL on failure.

To load the eBPF program that uses the bpf_skb_p4tc_tbl_lookup kfunc into
TC, we issue the following command:

tc filter add dev $P0 ingress protocol any prio 1 p4 pname redirect_srcip \
     action bpf obj $PROGNAME.o section p4prog/tc

To load the eBPF program that uses the bpf_xdp_p4tc_tbl_lookup into XDP,
we first need to load it into XDP using, for example, the ip command:

ip link set $P0 xdp obj $PROGNAME.o section p4prog/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_p4prog prog_cookie 22

Note that we also specify a "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.

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>
  • Loading branch information
@jhsmt @intel-lab-lkp
jhsmt authored and intel-lab-lkp committed May 17, 2023
1 parent bc27390 commit 80e79d4
Show file tree
Hide file tree
Showing 14 changed files with 682 additions and 24 deletions.
1 change: 1 addition & 0 deletions include/linux/bitops.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -19,6 +19,7 @@
#define BITS_TO_LONGS(nr) __KERNEL_DIV_ROUND_UP(nr, BITS_PER_TYPE(long))
#define BITS_TO_U64(nr) __KERNEL_DIV_ROUND_UP(nr, BITS_PER_TYPE(u64))
#define BITS_TO_U32(nr) __KERNEL_DIV_ROUND_UP(nr, BITS_PER_TYPE(u32))
#define BITS_TO_U16(nr) __KERNEL_DIV_ROUND_UP(nr, BITS_PER_TYPE(u16))
#define BITS_TO_BYTES(nr) __KERNEL_DIV_ROUND_UP(nr, BITS_PER_TYPE(char))

extern unsigned int __sw_hweight8(unsigned int w);
Expand Down
3 changes: 3 additions & 0 deletions include/linux/filter.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -577,6 +577,9 @@ typedef unsigned int (*bpf_dispatcher_fn)(const void *ctx,
const struct bpf_insn *insnsi,
unsigned int (*bpf_func)(const void *,
const struct bpf_insn *));
#ifndef CONFIG_NET_P4_TC_KFUNCS
extern int is_p4tc_kfunc(const struct bpf_reg_state *reg);
#endif

static __always_inline u32 __bpf_prog_run(const struct bpf_prog *prog,
const void *ctx,
Expand Down
94 changes: 92 additions & 2 deletions include/net/p4tc.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -37,11 +37,13 @@

struct p4tc_percpu_scratchpad {
u32 prog_cookie;
#ifndef CONFIG_NET_P4_TC_KFUNCS
u32 keysz;
u32 maskid;
u8 key[BITS_TO_BYTES(P4TC_MAX_KEYSZ)];
u8 hdrs[BITS_TO_BYTES(HEADER_MAX_LEN)];
u8 metadata[BITS_TO_BYTES(META_MAX_LEN)];
#endif
};

DECLARE_PER_CPU(struct p4tc_percpu_scratchpad, p4tc_percpu_scratchpad);
Expand Down Expand Up @@ -105,6 +107,7 @@ struct p4tc_template_common {

extern const struct p4tc_template_ops p4tc_pipeline_ops;

#ifndef CONFIG_NET_P4_TC_KFUNCS
struct p4tc_act_dep_edge_node {
struct list_head head;
u32 act_id;
Expand All @@ -115,24 +118,31 @@ struct p4tc_act_dep_node {
struct list_head head;
u32 act_id;
};
#endif

struct p4tc_pipeline {
struct p4tc_template_common common;
#ifndef CONFIG_NET_P4_TC_KFUNCS
struct idr p_meta_idr;
#endif
struct idr p_act_idr;
struct idr p_tbl_idr;
struct idr p_reg_idr;
struct rcu_head rcu;
struct net *net;
struct p4tc_parser *parser;
#ifndef CONFIG_NET_P4_TC_KFUNCS
struct tc_action **preacts;
int num_preacts;
struct tc_action **postacts;
int num_postacts;
struct list_head act_dep_graph;
struct list_head act_topological_order;
#endif
u32 max_rules;
#ifndef CONFIG_NET_P4_TC_KFUNCS
u32 p_meta_offset;
#endif
u32 num_created_acts;
refcount_t p_ref;
refcount_t p_ctrl_ref;
Expand All @@ -143,8 +153,28 @@ struct p4tc_pipeline {
refcount_t p_hdrs_used;
};

#define P4TC_PIPELINE_MAX_ARRAY 32

struct p4tc_table;

struct p4tc_tbl_cache_key {
u32 pipeid;
u32 tblid;
};

extern const struct rhashtable_params tbl_cache_ht_params;

int p4tc_tbl_cache_insert(struct net *net, u32 pipeid, struct p4tc_table *table);
void p4tc_tbl_cache_remove(struct net *net, struct p4tc_table *table);
struct p4tc_table *p4tc_tbl_cache_lookup(struct net *net, u32 pipeid, u32 tblid);

#define P4TC_TBLS_CACHE_SIZE 32

struct p4tc_pipeline_net {
struct idr pipeline_idr;
#ifdef CONFIG_NET_P4_TC_KFUNCS
struct list_head tbls_cache[P4TC_TBLS_CACHE_SIZE];
#endif
struct idr pipeline_idr;
};

int tcf_p4_tmpl_generic_dump(struct sk_buff *skb, struct p4tc_dump_ctx *ctx,
Expand Down Expand Up @@ -182,6 +212,7 @@ static inline bool pipeline_sealed(struct p4tc_pipeline *pipeline)
return pipeline->p_state == P4TC_STATE_READY;
}

#ifndef CONFIG_NET_P4_TC_KFUNCS
void tcf_pipeline_add_dep_edge(struct p4tc_pipeline *pipeline,
struct p4tc_act_dep_edge_node *edge_node,
u32 vertex_id);
Expand All @@ -194,7 +225,9 @@ int determine_act_topological_order(struct p4tc_pipeline *pipeline,
struct p4tc_act;
void tcf_pipeline_delete_from_dep_graph(struct p4tc_pipeline *pipeline,
struct p4tc_act *act);
#endif

#ifndef CONFIG_NET_P4_TC_KFUNCS
struct p4tc_metadata {
struct p4tc_template_common common;
struct rcu_head rcu;
Expand All @@ -209,6 +242,7 @@ struct p4tc_metadata {
};

extern const struct p4tc_template_ops p4tc_meta_ops;
#endif

struct p4tc_table_key {
struct tc_action **key_acts;
Expand All @@ -224,8 +258,24 @@ struct p4tc_table_key {

#define P4TC_PERMISSIONS_UNINIT (1 << P4TC_PERM_MAX_BIT)

#ifdef CONFIG_NET_P4_TC_KFUNCS
#define P4TC_MAX_PARAM_DATA_SIZE 124

struct p4tc_table_entry_act_bpf {
u32 act_id;
u8 params[P4TC_MAX_PARAM_DATA_SIZE];
} __packed;
#endif

struct p4tc_parser_buffer_act_bpf {
u16 hdrs[BITS_TO_U16(HEADER_MAX_LEN)];
};

struct p4tc_table_defact {
struct tc_action **default_acts;
#ifdef CONFIG_NET_P4_TC_KFUNCS
struct p4tc_table_entry_act_bpf *defact_bpf;
#endif
/* Will have 2 5 bits blocks containing CRUDX (Create, read, update,
* delete, execute) permissions for control plane and data plane.
* The first 5 bits are for control and the next five are for data plane.
Expand All @@ -242,13 +292,18 @@ struct p4tc_table_perm {

struct p4tc_table {
struct p4tc_template_common common;
struct list_head tbl_cache_node;
struct list_head tbl_acts_list;
#ifndef CONFIG_NET_P4_TC_KFUNCS
struct p4tc_table_key *tbl_key;
#endif
struct idr tbl_masks_idr;
struct ida tbl_prio_idr;
struct rhltable tbl_entries;
#ifndef CONFIG_NET_P4_TC_KFUNCS
struct tc_action **tbl_preacts;
struct tc_action **tbl_postacts;
#endif
struct p4tc_table_entry *tbl_const_entry;
struct p4tc_table_defact __rcu *tbl_default_hitact;
struct p4tc_table_defact __rcu *tbl_default_missact;
Expand Down Expand Up @@ -280,7 +335,10 @@ struct p4tc_ipv4_param_value {
u32 mask;
};


#ifndef CONFIG_NET_P4_TC_KFUNCS
#define P4TC_ACT_PARAM_FLAGS_ISDYN BIT(0)
#endif

struct p4tc_act_param {
char name[ACTPARAMNAMSIZ];
Expand All @@ -305,6 +363,7 @@ struct p4tc_act_param_ops {
u32 alloc_len;
};

#ifndef CONFIG_NET_P4_TC_KFUNCS
struct p4tc_label_key {
char *label;
u32 labelsz;
Expand All @@ -315,12 +374,15 @@ struct p4tc_label_node {
struct p4tc_label_key key;
int cmd_offset;
};
#endif

struct p4tc_act {
struct p4tc_template_common common;
struct tc_action_ops ops;
#ifndef CONFIG_NET_P4_TC_KFUNCS
struct rhashtable *labels;
struct list_head cmd_operations;
#endif
struct tc_action_net *tn;
struct p4tc_pipeline *pipeline;
struct idr params_idr;
Expand All @@ -345,6 +407,13 @@ void p4tc_label_ht_destroy(void *ptr, void *arg);

extern const struct rhashtable_params entry_hlt_params;

#ifdef CONFIG_NET_P4_TC_KFUNCS
struct p4tc_table_entry_act_bpf_params {
u32 pipeid;
u32 tblid;
};
#endif

struct p4tc_table_entry;
struct p4tc_table_entry_work {
struct work_struct work;
Expand All @@ -364,6 +433,9 @@ struct p4tc_table_entry_value {
u32 prio;
int num_acts;
struct tc_action **acts;
#ifdef CONFIG_NET_P4_TC_KFUNCS
struct p4tc_table_entry_act_bpf *act_bpf;
#endif
refcount_t entries_ref;
u32 permissions;
struct p4tc_table_entry_tm __rcu *tm;
Expand Down Expand Up @@ -395,13 +467,24 @@ static inline void *p4tc_table_entry_value(struct p4tc_table_entry *entry)

extern const struct nla_policy p4tc_root_policy[P4TC_ROOT_MAX + 1];
extern const struct nla_policy p4tc_policy[P4TC_MAX + 1];
#ifndef CONFIG_NET_P4_TC_KFUNCS
struct p4tc_table_entry *p4tc_table_entry_lookup(struct sk_buff *skb,
struct p4tc_table *table,
u32 keysz);
#endif
struct p4tc_table_entry *
p4tc_table_entry_lookup_direct(struct p4tc_table *table,
struct p4tc_table_entry_key *key);
int __tcf_table_entry_del(struct p4tc_pipeline *pipeline,
struct p4tc_table *table,
struct p4tc_table_entry_key *key,
struct p4tc_table_entry_mask *mask, u32 prio);
#ifdef CONFIG_NET_P4_TC_KFUNCS
struct p4tc_table_entry_act_bpf *
tcf_table_entry_create_act_bpf(struct tc_action *action,
struct netlink_ext_ack *extack);
#endif
int register_p4tc_tbl_bpf(void);

struct p4tc_parser {
char parser_name[PARSERNAMSIZ];
Expand Down Expand Up @@ -439,6 +522,7 @@ struct p4tc_register {

extern const struct p4tc_template_ops p4tc_register_ops;

#ifndef CONFIG_NET_P4_TC_KFUNCS
struct p4tc_metadata *tcf_meta_find_byid(struct p4tc_pipeline *pipeline,
u32 m_id);
void tcf_meta_fill_user_offsets(struct p4tc_pipeline *pipeline);
Expand All @@ -448,6 +532,7 @@ struct p4tc_metadata *tcf_meta_get(struct p4tc_pipeline *pipeline,
struct netlink_ext_ack *extack);
void tcf_meta_put_ref(struct p4tc_metadata *meta);
void *tcf_meta_fetch(struct sk_buff *skb, struct p4tc_metadata *meta);
#endif

static inline int p4tc_action_init(struct net *net, struct nlattr *nla,
struct tc_action *acts[], u32 pipeid,
Expand Down Expand Up @@ -553,12 +638,13 @@ struct p4tc_hdrfield *tcf_hdrfield_find_byany(struct p4tc_parser *parser,
const char *hdrfield_name,
u32 hdrfield_id,
struct netlink_ext_ack *extack);
#ifndef CONFIG_NET_P4_TC_KFUNCS
void *tcf_hdrfield_fetch(struct sk_buff *skb, struct p4tc_hdrfield *hdrfield);
#endif
struct p4tc_hdrfield *tcf_hdrfield_get(struct p4tc_parser *parser,
const char *hdrfield_name,
u32 hdrfield_id,
struct netlink_ext_ack *extack);
void *tcf_hdrfield_fetch(struct sk_buff *skb, struct p4tc_hdrfield *hdrfield);
void tcf_hdrfield_put_ref(struct p4tc_hdrfield *hdrfield);

int p4tc_init_net_ops(struct net *net, unsigned int id);
Expand Down Expand Up @@ -595,13 +681,16 @@ struct p4tc_register *tcf_register_find_byany(struct p4tc_pipeline *pipeline,
void tcf_register_put_rcu(struct rcu_head *head);

#define to_pipeline(t) ((struct p4tc_pipeline *)t)
#ifndef CONFIG_NET_P4_TC_KFUNCS
#define to_meta(t) ((struct p4tc_metadata *)t)
#endif
#define to_hdrfield(t) ((struct p4tc_hdrfield *)t)
#define to_act(t) ((struct p4tc_act *)t)
#define to_table(t) ((struct p4tc_table *)t)
#define to_register(t) ((struct p4tc_register *)t)

/* P4TC COMMANDS */
#ifndef CONFIG_NET_P4_TC_KFUNCS
int p4tc_cmds_parse(struct net *net, struct p4tc_act *act, struct nlattr *nla,
bool ovr, struct netlink_ext_ack *extack);
int p4tc_cmds_copy(struct p4tc_act *act, struct list_head *new_cmd_operations,
Expand Down Expand Up @@ -680,5 +769,6 @@ static inline int __p4tc_cmd_run(struct sk_buff *skb, struct p4tc_cmd_operate *o
return op->cmd->run(skb, op, cmd, res);
}
#endif
#endif

#endif
10 changes: 10 additions & 0 deletions net/core/filter.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -8758,6 +8758,11 @@ static int tc_cls_act_btf_struct_access(struct bpf_verifier_log *log,
{
int ret = -EACCES;

#ifndef CONFIG_NET_P4_TC_KFUNCS
if (is_p4tc_kfunc(reg))
return 0;
#endif

mutex_lock(&nf_conn_btf_access_lock);
if (nfct_btf_struct_access)
ret = nfct_btf_struct_access(log, reg, off, size);
Expand Down Expand Up @@ -8831,6 +8836,11 @@ static int xdp_btf_struct_access(struct bpf_verifier_log *log,
{
int ret = -EACCES;

#ifndef CONFIG_NET_P4_TC_KFUNCS
if (is_p4tc_kfunc(reg))
return 0;
#endif

mutex_lock(&nf_conn_btf_access_lock);
if (nfct_btf_struct_access)
ret = nfct_btf_struct_access(log, reg, off, size);
Expand Down
7 changes: 7 additions & 0 deletions net/sched/Kconfig
View file
Original file line number Diff line number Diff line change
Expand Up @@ -696,6 +696,13 @@ config NET_P4_TC
The concept of Pipelines, Tables, metadata will be enabled
with this option.

config NET_P4_TC_KFUNCS
bool "P4 TC support for eBPF SW data path"
depends on NET_P4_TC
select NET_CLS_ACT
help
Say Y here if you want to use P4 with eBPF SW data path.

config NET_CLS_ACT
bool "Actions"
select NET_CLS
Expand Down
4 changes: 4 additions & 0 deletions net/sched/cls_p4.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -46,8 +46,10 @@ static int p4_classify(struct sk_buff *skb, const struct tcf_proto *tp,
bool at_ingress = skb_at_tc_ingress(skb);
int rc = TC_ACT_PIPE;
struct p4tc_percpu_scratchpad *pad;
#ifndef CONFIG_NET_P4_TC_KFUNCS
struct tcf_result p4res = {};
struct p4tc_pipeline *pipeline;
#endif

if (unlikely(!head)) {
pr_err("P4 classifier not found\n");
Expand Down Expand Up @@ -85,6 +87,7 @@ static int p4_classify(struct sk_buff *skb, const struct tcf_proto *tp,
if (rc != TC_ACT_PIPE)
goto zero_pad;

#ifndef CONFIG_NET_P4_TC_KFUNCS
pipeline = head->pipeline;
trace_p4_classify(skb, pipeline);

Expand All @@ -97,6 +100,7 @@ static int p4_classify(struct sk_buff *skb, const struct tcf_proto *tp,
&p4res);
if (rc != TC_ACT_PIPE)
goto zero_pad;
#endif

*res = head->res;

Expand Down
8 changes: 6 additions & 2 deletions net/sched/p4tc/Makefile
View file
Original file line number Diff line number Diff line change
Expand Up @@ -2,6 +2,10 @@

CFLAGS_trace.o := -I$(src)

obj-y := p4tc_types.o p4tc_pipeline.o p4tc_tmpl_api.o p4tc_meta.o \
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_api.o p4tc_register.o p4tc_cmds.o trace.o
p4tc_tbl_api.o p4tc_register.o p4tc_bpf.o trace.o

ifndef CONFIG_NET_P4_TC_KFUNCS
obj-y += p4tc_meta.o p4tc_cmds.o
endif

0 comments on commit 80e79d4

Please sign in to comment.