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bpf: Print function name in addition to function id 

The verifier currently prints raw function ids when printing CALL
instructions or when complaining:

	5: (85) call 23
	unknown func 23

print a meaningful function name instead:

	5: (85) call bpf_redirect#23
	unknown func bpf_redirect#23

Moves the function documentation to a single comment and renames all
helpers names in the list to conform to the bpf_ prefix notation so
they can be greped in the kernel source.

Signed-off-by: Thomas Graf <tgraf@suug.ch>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
zero-colors
Thomas Graf 2016-10-27 11:23:51 +02:00 committed by David S. Miller
parent 46b5ab1a7c
commit ebb676daa1
2 changed files with 316 additions and 293 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

574
include/uapi/linux/bpf.h
View File

@ -143,297 +143,301 @@ union bpf_attr {
};
} __attribute__((aligned(8)));
/* BPF helper function descriptions:
*
* void *bpf_map_lookup_elem(&map, &key)
* Return: Map value or NULL
*
* int bpf_map_update_elem(&map, &key, &value, flags)
* Return: 0 on success or negative error
*
* int bpf_map_delete_elem(&map, &key)
* Return: 0 on success or negative error
*
* int bpf_probe_read(void *dst, int size, void *src)
* Return: 0 on success or negative error
*
* u64 bpf_ktime_get_ns(void)
* Return: current ktime
*
* int bpf_trace_printk(const char *fmt, int fmt_size, ...)
* Return: length of buffer written or negative error
*
* u32 bpf_prandom_u32(void)
* Return: random value
*
* u32 bpf_raw_smp_processor_id(void)
* Return: SMP processor ID
*
* int bpf_skb_store_bytes(skb, offset, from, len, flags)
* store bytes into packet
* @skb: pointer to skb
* @offset: offset within packet from skb->mac_header
* @from: pointer where to copy bytes from
* @len: number of bytes to store into packet
* @flags: bit 0 - if true, recompute skb->csum
* other bits - reserved
* Return: 0 on success or negative error
*
* int bpf_l3_csum_replace(skb, offset, from, to, flags)
* recompute IP checksum
* @skb: pointer to skb
* @offset: offset within packet where IP checksum is located
* @from: old value of header field
* @to: new value of header field
* @flags: bits 0-3 - size of header field
* other bits - reserved
* Return: 0 on success or negative error
*
* int bpf_l4_csum_replace(skb, offset, from, to, flags)
* recompute TCP/UDP checksum
* @skb: pointer to skb
* @offset: offset within packet where TCP/UDP checksum is located
* @from: old value of header field
* @to: new value of header field
* @flags: bits 0-3 - size of header field
* bit 4 - is pseudo header
* other bits - reserved
* Return: 0 on success or negative error
*
* int bpf_tail_call(ctx, prog_array_map, index)
* jump into another BPF program
* @ctx: context pointer passed to next program
* @prog_array_map: pointer to map which type is BPF_MAP_TYPE_PROG_ARRAY
* @index: index inside array that selects specific program to run
* Return: 0 on success or negative error
*
* int bpf_clone_redirect(skb, ifindex, flags)
* redirect to another netdev
* @skb: pointer to skb
* @ifindex: ifindex of the net device
* @flags: bit 0 - if set, redirect to ingress instead of egress
* other bits - reserved
* Return: 0 on success or negative error
*
* u64 bpf_get_current_pid_tgid(void)
* Return: current->tgid << 32 | current->pid
*
* u64 bpf_get_current_uid_gid(void)
* Return: current_gid << 32 | current_uid
*
* int bpf_get_current_comm(char *buf, int size_of_buf)
* stores current->comm into buf
* Return: 0 on success or negative error
*
* u32 bpf_get_cgroup_classid(skb)
* retrieve a proc's classid
* @skb: pointer to skb
* Return: classid if != 0
*
* int bpf_skb_vlan_push(skb, vlan_proto, vlan_tci)
* Return: 0 on success or negative error
*
* int bpf_skb_vlan_pop(skb)
* Return: 0 on success or negative error
*
* int bpf_skb_get_tunnel_key(skb, key, size, flags)
* int bpf_skb_set_tunnel_key(skb, key, size, flags)
* retrieve or populate tunnel metadata
* @skb: pointer to skb
* @key: pointer to 'struct bpf_tunnel_key'
* @size: size of 'struct bpf_tunnel_key'
* @flags: room for future extensions
* Return: 0 on success or negative error
*
* u64 bpf_perf_event_read(&map, index)
* Return: Number events read or error code
*
* int bpf_redirect(ifindex, flags)
* redirect to another netdev
* @ifindex: ifindex of the net device
* @flags: bit 0 - if set, redirect to ingress instead of egress
* other bits - reserved
* Return: TC_ACT_REDIRECT
*
* u32 bpf_get_route_realm(skb)
* retrieve a dst's tclassid
* @skb: pointer to skb
* Return: realm if != 0
*
* int bpf_perf_event_output(ctx, map, index, data, size)
* output perf raw sample
* @ctx: struct pt_regs*
* @map: pointer to perf_event_array map
* @index: index of event in the map
* @data: data on stack to be output as raw data
* @size: size of data
* Return: 0 on success or negative error
*
* int bpf_get_stackid(ctx, map, flags)
* walk user or kernel stack and return id
* @ctx: struct pt_regs*
* @map: pointer to stack_trace map
* @flags: bits 0-7 - numer of stack frames to skip
* bit 8 - collect user stack instead of kernel
* bit 9 - compare stacks by hash only
* bit 10 - if two different stacks hash into the same stackid
* discard old
* other bits - reserved
* Return: >= 0 stackid on success or negative error
*
* s64 bpf_csum_diff(from, from_size, to, to_size, seed)
* calculate csum diff
* @from: raw from buffer
* @from_size: length of from buffer
* @to: raw to buffer
* @to_size: length of to buffer
* @seed: optional seed
* Return: csum result or negative error code
*
* int bpf_skb_get_tunnel_opt(skb, opt, size)
* retrieve tunnel options metadata
* @skb: pointer to skb
* @opt: pointer to raw tunnel option data
* @size: size of @opt
* Return: option size
*
* int bpf_skb_set_tunnel_opt(skb, opt, size)
* populate tunnel options metadata
* @skb: pointer to skb
* @opt: pointer to raw tunnel option data
* @size: size of @opt
* Return: 0 on success or negative error
*
* int bpf_skb_change_proto(skb, proto, flags)
* Change protocol of the skb. Currently supported is v4 -> v6,
* v6 -> v4 transitions. The helper will also resize the skb. eBPF
* program is expected to fill the new headers via skb_store_bytes
* and lX_csum_replace.
* @skb: pointer to skb
* @proto: new skb->protocol type
* @flags: reserved
* Return: 0 on success or negative error
*
* int bpf_skb_change_type(skb, type)
* Change packet type of skb.
* @skb: pointer to skb
* @type: new skb->pkt_type type
* Return: 0 on success or negative error
*
* int bpf_skb_under_cgroup(skb, map, index)
* Check cgroup2 membership of skb
* @skb: pointer to skb
* @map: pointer to bpf_map in BPF_MAP_TYPE_CGROUP_ARRAY type
* @index: index of the cgroup in the bpf_map
* Return:
* == 0 skb failed the cgroup2 descendant test
* == 1 skb succeeded the cgroup2 descendant test
* < 0 error
*
* u32 bpf_get_hash_recalc(skb)
* Retrieve and possibly recalculate skb->hash.
* @skb: pointer to skb
* Return: hash
*
* u64 bpf_get_current_task(void)
* Returns current task_struct
* Return: current
*
* int bpf_probe_write_user(void *dst, void *src, int len)
* safely attempt to write to a location
* @dst: destination address in userspace
* @src: source address on stack
* @len: number of bytes to copy
* Return: 0 on success or negative error
*
* int bpf_current_task_under_cgroup(map, index)
* Check cgroup2 membership of current task
* @map: pointer to bpf_map in BPF_MAP_TYPE_CGROUP_ARRAY type
* @index: index of the cgroup in the bpf_map
* Return:
* == 0 current failed the cgroup2 descendant test
* == 1 current succeeded the cgroup2 descendant test
* < 0 error
*
* int bpf_skb_change_tail(skb, len, flags)
* The helper will resize the skb to the given new size, to be used f.e.
* with control messages.
* @skb: pointer to skb
* @len: new skb length
* @flags: reserved
* Return: 0 on success or negative error
*
* int bpf_skb_pull_data(skb, len)
* The helper will pull in non-linear data in case the skb is non-linear
* and not all of len are part of the linear section. Only needed for
* read/write with direct packet access.
* @skb: pointer to skb
* @len: len to make read/writeable
* Return: 0 on success or negative error
*
* s64 bpf_csum_update(skb, csum)
* Adds csum into skb->csum in case of CHECKSUM_COMPLETE.
* @skb: pointer to skb
* @csum: csum to add
* Return: csum on success or negative error
*
* void bpf_set_hash_invalid(skb)
* Invalidate current skb->hash.
* @skb: pointer to skb
*
* int bpf_get_numa_node_id()
* Return: Id of current NUMA node.
*/
#define __BPF_FUNC_MAPPER(FN) \
FN(unspec), \
FN(map_lookup_elem), \
FN(map_update_elem), \
FN(map_delete_elem), \
FN(probe_read), \
FN(ktime_get_ns), \
FN(trace_printk), \
FN(get_prandom_u32), \
FN(get_smp_processor_id), \
FN(skb_store_bytes), \
FN(l3_csum_replace), \
FN(l4_csum_replace), \
FN(tail_call), \
FN(clone_redirect), \
FN(get_current_pid_tgid), \
FN(get_current_uid_gid), \
FN(get_current_comm), \
FN(get_cgroup_classid), \
FN(skb_vlan_push), \
FN(skb_vlan_pop), \
FN(skb_get_tunnel_key), \
FN(skb_set_tunnel_key), \
FN(perf_event_read), \
FN(redirect), \
FN(get_route_realm), \
FN(perf_event_output), \
FN(skb_load_bytes), \
FN(get_stackid), \
FN(csum_diff), \
FN(skb_get_tunnel_opt), \
FN(skb_set_tunnel_opt), \
FN(skb_change_proto), \
FN(skb_change_type), \
FN(skb_under_cgroup), \
FN(get_hash_recalc), \
FN(get_current_task), \
FN(probe_write_user), \
FN(current_task_under_cgroup), \
FN(skb_change_tail), \
FN(skb_pull_data), \
FN(csum_update), \
FN(set_hash_invalid), \
FN(get_numa_node_id),
/* integer value in 'imm' field of BPF_CALL instruction selects which helper
* function eBPF program intends to call
*/
#define __BPF_ENUM_FN(x) BPF_FUNC_ ## x
enum bpf_func_id {
BPF_FUNC_unspec,
BPF_FUNC_map_lookup_elem, /* void *map_lookup_elem(&map, &key) */
BPF_FUNC_map_update_elem, /* int map_update_elem(&map, &key, &value, flags) */
BPF_FUNC_map_delete_elem, /* int map_delete_elem(&map, &key) */
BPF_FUNC_probe_read, /* int bpf_probe_read(void *dst, int size, void *src) */
BPF_FUNC_ktime_get_ns, /* u64 bpf_ktime_get_ns(void) */
BPF_FUNC_trace_printk, /* int bpf_trace_printk(const char *fmt, int fmt_size, ...) */
BPF_FUNC_get_prandom_u32, /* u32 prandom_u32(void) */
BPF_FUNC_get_smp_processor_id, /* u32 raw_smp_processor_id(void) */
/**
* skb_store_bytes(skb, offset, from, len, flags) - store bytes into packet
* @skb: pointer to skb
* @offset: offset within packet from skb->mac_header
* @from: pointer where to copy bytes from
* @len: number of bytes to store into packet
* @flags: bit 0 - if true, recompute skb->csum
* other bits - reserved
* Return: 0 on success
*/
BPF_FUNC_skb_store_bytes,
/**
* l3_csum_replace(skb, offset, from, to, flags) - recompute IP checksum
* @skb: pointer to skb
* @offset: offset within packet where IP checksum is located
* @from: old value of header field
* @to: new value of header field
* @flags: bits 0-3 - size of header field
* other bits - reserved
* Return: 0 on success
*/
BPF_FUNC_l3_csum_replace,
/**
* l4_csum_replace(skb, offset, from, to, flags) - recompute TCP/UDP checksum
* @skb: pointer to skb
* @offset: offset within packet where TCP/UDP checksum is located
* @from: old value of header field
* @to: new value of header field
* @flags: bits 0-3 - size of header field
* bit 4 - is pseudo header
* other bits - reserved
* Return: 0 on success
*/
BPF_FUNC_l4_csum_replace,
/**
* bpf_tail_call(ctx, prog_array_map, index) - jump into another BPF program
* @ctx: context pointer passed to next program
* @prog_array_map: pointer to map which type is BPF_MAP_TYPE_PROG_ARRAY
* @index: index inside array that selects specific program to run
* Return: 0 on success
*/
BPF_FUNC_tail_call,
/**
* bpf_clone_redirect(skb, ifindex, flags) - redirect to another netdev
* @skb: pointer to skb
* @ifindex: ifindex of the net device
* @flags: bit 0 - if set, redirect to ingress instead of egress
* other bits - reserved
* Return: 0 on success
*/
BPF_FUNC_clone_redirect,
/**
* u64 bpf_get_current_pid_tgid(void)
* Return: current->tgid << 32 | current->pid
*/
BPF_FUNC_get_current_pid_tgid,
/**
* u64 bpf_get_current_uid_gid(void)
* Return: current_gid << 32 | current_uid
*/
BPF_FUNC_get_current_uid_gid,
/**
* bpf_get_current_comm(char *buf, int size_of_buf)
* stores current->comm into buf
* Return: 0 on success
*/
BPF_FUNC_get_current_comm,
/**
* bpf_get_cgroup_classid(skb) - retrieve a proc's classid
* @skb: pointer to skb
* Return: classid if != 0
*/
BPF_FUNC_get_cgroup_classid,
BPF_FUNC_skb_vlan_push, /* bpf_skb_vlan_push(skb, vlan_proto, vlan_tci) */
BPF_FUNC_skb_vlan_pop, /* bpf_skb_vlan_pop(skb) */
/**
* bpf_skb_[gs]et_tunnel_key(skb, key, size, flags)
* retrieve or populate tunnel metadata
* @skb: pointer to skb
* @key: pointer to 'struct bpf_tunnel_key'
* @size: size of 'struct bpf_tunnel_key'
* @flags: room for future extensions
* Retrun: 0 on success
*/
BPF_FUNC_skb_get_tunnel_key,
BPF_FUNC_skb_set_tunnel_key,
BPF_FUNC_perf_event_read, /* u64 bpf_perf_event_read(&map, index) */
/**
* bpf_redirect(ifindex, flags) - redirect to another netdev
* @ifindex: ifindex of the net device
* @flags: bit 0 - if set, redirect to ingress instead of egress
* other bits - reserved
* Return: TC_ACT_REDIRECT
*/
BPF_FUNC_redirect,
/**
* bpf_get_route_realm(skb) - retrieve a dst's tclassid
* @skb: pointer to skb
* Return: realm if != 0
*/
BPF_FUNC_get_route_realm,
/**
* bpf_perf_event_output(ctx, map, index, data, size) - output perf raw sample
* @ctx: struct pt_regs*
* @map: pointer to perf_event_array map
* @index: index of event in the map
* @data: data on stack to be output as raw data
* @size: size of data
* Return: 0 on success
*/
BPF_FUNC_perf_event_output,
BPF_FUNC_skb_load_bytes,
/**
* bpf_get_stackid(ctx, map, flags) - walk user or kernel stack and return id
* @ctx: struct pt_regs*
* @map: pointer to stack_trace map
* @flags: bits 0-7 - numer of stack frames to skip
* bit 8 - collect user stack instead of kernel
* bit 9 - compare stacks by hash only
* bit 10 - if two different stacks hash into the same stackid
* discard old
* other bits - reserved
* Return: >= 0 stackid on success or negative error
*/
BPF_FUNC_get_stackid,
/**
* bpf_csum_diff(from, from_size, to, to_size, seed) - calculate csum diff
* @from: raw from buffer
* @from_size: length of from buffer
* @to: raw to buffer
* @to_size: length of to buffer
* @seed: optional seed
* Return: csum result
*/
BPF_FUNC_csum_diff,
/**
* bpf_skb_[gs]et_tunnel_opt(skb, opt, size)
* retrieve or populate tunnel options metadata
* @skb: pointer to skb
* @opt: pointer to raw tunnel option data
* @size: size of @opt
* Return: 0 on success for set, option size for get
*/
BPF_FUNC_skb_get_tunnel_opt,
BPF_FUNC_skb_set_tunnel_opt,
/**
* bpf_skb_change_proto(skb, proto, flags)
* Change protocol of the skb. Currently supported is
* v4 -> v6, v6 -> v4 transitions. The helper will also
* resize the skb. eBPF program is expected to fill the
* new headers via skb_store_bytes and lX_csum_replace.
* @skb: pointer to skb
* @proto: new skb->protocol type
* @flags: reserved
* Return: 0 on success or negative error
*/
BPF_FUNC_skb_change_proto,
/**
* bpf_skb_change_type(skb, type)
* Change packet type of skb.
* @skb: pointer to skb
* @type: new skb->pkt_type type
* Return: 0 on success or negative error
*/
BPF_FUNC_skb_change_type,
/**
* bpf_skb_under_cgroup(skb, map, index) - Check cgroup2 membership of skb
* @skb: pointer to skb
* @map: pointer to bpf_map in BPF_MAP_TYPE_CGROUP_ARRAY type
* @index: index of the cgroup in the bpf_map
* Return:
* == 0 skb failed the cgroup2 descendant test
* == 1 skb succeeded the cgroup2 descendant test
* < 0 error
*/
BPF_FUNC_skb_under_cgroup,
/**
* bpf_get_hash_recalc(skb)
* Retrieve and possibly recalculate skb->hash.
* @skb: pointer to skb
* Return: hash
*/
BPF_FUNC_get_hash_recalc,
/**
* u64 bpf_get_current_task(void)
* Returns current task_struct
* Return: current
*/
BPF_FUNC_get_current_task,
/**
* bpf_probe_write_user(void *dst, void *src, int len)
* safely attempt to write to a location
* @dst: destination address in userspace
* @src: source address on stack
* @len: number of bytes to copy
* Return: 0 on success or negative error
*/
BPF_FUNC_probe_write_user,
/**
* bpf_current_task_under_cgroup(map, index) - Check cgroup2 membership of current task
* @map: pointer to bpf_map in BPF_MAP_TYPE_CGROUP_ARRAY type
* @index: index of the cgroup in the bpf_map
* Return:
* == 0 current failed the cgroup2 descendant test
* == 1 current succeeded the cgroup2 descendant test
* < 0 error
*/
BPF_FUNC_current_task_under_cgroup,
/**
* bpf_skb_change_tail(skb, len, flags)
* The helper will resize the skb to the given new size,
* to be used f.e. with control messages.
* @skb: pointer to skb
* @len: new skb length
* @flags: reserved
* Return: 0 on success or negative error
*/
BPF_FUNC_skb_change_tail,
/**
* bpf_skb_pull_data(skb, len)
* The helper will pull in non-linear data in case the
* skb is non-linear and not all of len are part of the
* linear section. Only needed for read/write with direct
* packet access.
* @skb: pointer to skb
* @len: len to make read/writeable
* Return: 0 on success or negative error
*/
BPF_FUNC_skb_pull_data,
/**
* bpf_csum_update(skb, csum)
* Adds csum into skb->csum in case of CHECKSUM_COMPLETE.
* @skb: pointer to skb
* @csum: csum to add
* Return: csum on success or negative error
*/
BPF_FUNC_csum_update,
/**
* bpf_set_hash_invalid(skb)
* Invalidate current skb>hash.
* @skb: pointer to skb
*/
BPF_FUNC_set_hash_invalid,
/**
* bpf_get_numa_node_id()
* Returns the id of the current NUMA node.
*/
BPF_FUNC_get_numa_node_id,
__BPF_FUNC_MAPPER(__BPF_ENUM_FN)
__BPF_FUNC_MAX_ID,
};
#undef __BPF_ENUM_FN
/* All flags used by eBPF helper functions, placed here. */

35
kernel/bpf/verifier.c
View File

@ -19,6 +19,7 @@
#include <net/netlink.h>
#include <linux/file.h>
#include <linux/vmalloc.h>
#include <linux/stringify.h>
/* bpf_check() is a static code analyzer that walks eBPF program
* instruction by instruction and updates register/stack state.
@ -190,6 +191,22 @@ static const char * const reg_type_str[] = {
[PTR_TO_PACKET_END] = "pkt_end",
};
#define __BPF_FUNC_STR_FN(x) [BPF_FUNC_ ## x] = __stringify(bpf_ ## x)
static const char * const func_id_str[] = {
__BPF_FUNC_MAPPER(__BPF_FUNC_STR_FN)
};
#undef __BPF_FUNC_STR_FN
static const char *func_id_name(int id)
{
BUILD_BUG_ON(ARRAY_SIZE(func_id_str) != __BPF_FUNC_MAX_ID);
if (id >= 0 && id < __BPF_FUNC_MAX_ID && func_id_str[id])
return func_id_str[id];
else
return "unknown";
}
static void print_verifier_state(struct bpf_verifier_state *state)
{
struct bpf_reg_state *reg;
@ -354,7 +371,8 @@ static void print_bpf_insn(struct bpf_insn *insn)
u8 opcode = BPF_OP(insn->code);
if (opcode == BPF_CALL) {
verbose("(%02x) call %d\n", insn->code, insn->imm);
verbose("(%02x) call %s#%d\n", insn->code,
func_id_name(insn->imm), insn->imm);
} else if (insn->code == (BPF_JMP | BPF_JA)) {
verbose("(%02x) goto pc%+d\n",
insn->code, insn->off);
@ -1114,8 +1132,8 @@ static int check_map_func_compatibility(struct bpf_map *map, int func_id)
return 0;
error:
verbose("cannot pass map_type %d into func %d\n",
map->map_type, func_id);
verbose("cannot pass map_type %d into func %s#%d\n",
map->map_type, func_id_name(func_id), func_id);
return -EINVAL;
}
@ -1172,7 +1190,7 @@ static int check_call(struct bpf_verifier_env *env, int func_id)
/* find function prototype */
if (func_id < 0 || func_id >= __BPF_FUNC_MAX_ID) {
verbose("invalid func %d\n", func_id);
verbose("invalid func %s#%d\n", func_id_name(func_id), func_id);
return -EINVAL;
}
@ -1180,7 +1198,7 @@ static int check_call(struct bpf_verifier_env *env, int func_id)
fn = env->prog->aux->ops->get_func_proto(func_id);
if (!fn) {
verbose("unknown func %d\n", func_id);
verbose("unknown func %s#%d\n", func_id_name(func_id), func_id);
return -EINVAL;
}
@ -1200,7 +1218,8 @@ static int check_call(struct bpf_verifier_env *env, int func_id)
*/
err = check_raw_mode(fn);
if (err) {
verbose("kernel subsystem misconfigured func %d\n", func_id);
verbose("kernel subsystem misconfigured func %s#%d\n",
func_id_name(func_id), func_id);
return err;
}
@ -1256,8 +1275,8 @@ static int check_call(struct bpf_verifier_env *env, int func_id)
regs[BPF_REG_0].map_ptr = meta.map_ptr;
regs[BPF_REG_0].id = ++env->id_gen;
} else {
verbose("unknown return type %d of func %d\n",
fn->ret_type, func_id);
verbose("unknown return type %d of func %s#%d\n",
fn->ret_type, func_id_name(func_id), func_id);
return -EINVAL;
}