linux/tools/bpf/bpftool/net.c
Stanislav Fomichev 7f0c57fec8 bpftool: show flow_dissector attachment status
Right now there is no way to query whether BPF flow_dissector program
is attached to a network namespace or not. In previous commit, I added
support for querying that info, show it when doing `bpftool net`:

$ bpftool prog loadall ./bpf_flow.o \
	/sys/fs/bpf/flow type flow_dissector \
	pinmaps /sys/fs/bpf/flow
$ bpftool prog
3: flow_dissector  name _dissect  tag 8c9e917b513dd5cc  gpl
        loaded_at 2019-04-23T16:14:48-0700  uid 0
        xlated 656B  jited 461B  memlock 4096B  map_ids 1,2
        btf_id 1
...

$ bpftool net -j
[{"xdp":[],"tc":[],"flow_dissector":[]}]

$ bpftool prog attach pinned \
	/sys/fs/bpf/flow/flow_dissector flow_dissector
$ bpftool net -j
[{"xdp":[],"tc":[],"flow_dissector":["id":3]}]

Doesn't show up in a different net namespace:
$ ip netns add test
$ ip netns exec test bpftool net -j
[{"xdp":[],"tc":[],"flow_dissector":[]}]

Non-json output:
$ bpftool net
xdp:

tc:

flow_dissector:
id 3

v2:
* initialization order (Jakub Kicinski)
* clear errno for batch mode (Quentin Monnet)

Signed-off-by: Stanislav Fomichev <sdf@google.com>
Reviewed-by: Quentin Monnet <quentin.monnet@netronome.com>
Reviewed-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
2019-04-25 23:49:06 +02:00

330 lines
7.4 KiB
C

// SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
// Copyright (C) 2018 Facebook
#define _GNU_SOURCE
#include <errno.h>
#include <fcntl.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <libbpf.h>
#include <net/if.h>
#include <linux/if.h>
#include <linux/rtnetlink.h>
#include <linux/tc_act/tc_bpf.h>
#include <sys/socket.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <bpf.h>
#include <nlattr.h>
#include "main.h"
#include "netlink_dumper.h"
struct ip_devname_ifindex {
char devname[64];
int ifindex;
};
struct bpf_netdev_t {
struct ip_devname_ifindex *devices;
int used_len;
int array_len;
int filter_idx;
};
struct tc_kind_handle {
char kind[64];
int handle;
};
struct bpf_tcinfo_t {
struct tc_kind_handle *handle_array;
int used_len;
int array_len;
bool is_qdisc;
};
struct bpf_filter_t {
const char *kind;
const char *devname;
int ifindex;
};
struct bpf_attach_info {
__u32 flow_dissector_id;
};
static int dump_link_nlmsg(void *cookie, void *msg, struct nlattr **tb)
{
struct bpf_netdev_t *netinfo = cookie;
struct ifinfomsg *ifinfo = msg;
if (netinfo->filter_idx > 0 && netinfo->filter_idx != ifinfo->ifi_index)
return 0;
if (netinfo->used_len == netinfo->array_len) {
netinfo->devices = realloc(netinfo->devices,
(netinfo->array_len + 16) *
sizeof(struct ip_devname_ifindex));
if (!netinfo->devices)
return -ENOMEM;
netinfo->array_len += 16;
}
netinfo->devices[netinfo->used_len].ifindex = ifinfo->ifi_index;
snprintf(netinfo->devices[netinfo->used_len].devname,
sizeof(netinfo->devices[netinfo->used_len].devname),
"%s",
tb[IFLA_IFNAME]
? libbpf_nla_getattr_str(tb[IFLA_IFNAME])
: "");
netinfo->used_len++;
return do_xdp_dump(ifinfo, tb);
}
static int dump_class_qdisc_nlmsg(void *cookie, void *msg, struct nlattr **tb)
{
struct bpf_tcinfo_t *tcinfo = cookie;
struct tcmsg *info = msg;
if (tcinfo->is_qdisc) {
/* skip clsact qdisc */
if (tb[TCA_KIND] &&
strcmp(libbpf_nla_data(tb[TCA_KIND]), "clsact") == 0)
return 0;
if (info->tcm_handle == 0)
return 0;
}
if (tcinfo->used_len == tcinfo->array_len) {
tcinfo->handle_array = realloc(tcinfo->handle_array,
(tcinfo->array_len + 16) * sizeof(struct tc_kind_handle));
if (!tcinfo->handle_array)
return -ENOMEM;
tcinfo->array_len += 16;
}
tcinfo->handle_array[tcinfo->used_len].handle = info->tcm_handle;
snprintf(tcinfo->handle_array[tcinfo->used_len].kind,
sizeof(tcinfo->handle_array[tcinfo->used_len].kind),
"%s",
tb[TCA_KIND]
? libbpf_nla_getattr_str(tb[TCA_KIND])
: "unknown");
tcinfo->used_len++;
return 0;
}
static int dump_filter_nlmsg(void *cookie, void *msg, struct nlattr **tb)
{
const struct bpf_filter_t *filter_info = cookie;
return do_filter_dump((struct tcmsg *)msg, tb, filter_info->kind,
filter_info->devname, filter_info->ifindex);
}
static int show_dev_tc_bpf(int sock, unsigned int nl_pid,
struct ip_devname_ifindex *dev)
{
struct bpf_filter_t filter_info;
struct bpf_tcinfo_t tcinfo;
int i, handle, ret = 0;
tcinfo.handle_array = NULL;
tcinfo.used_len = 0;
tcinfo.array_len = 0;
tcinfo.is_qdisc = false;
ret = libbpf_nl_get_class(sock, nl_pid, dev->ifindex,
dump_class_qdisc_nlmsg, &tcinfo);
if (ret)
goto out;
tcinfo.is_qdisc = true;
ret = libbpf_nl_get_qdisc(sock, nl_pid, dev->ifindex,
dump_class_qdisc_nlmsg, &tcinfo);
if (ret)
goto out;
filter_info.devname = dev->devname;
filter_info.ifindex = dev->ifindex;
for (i = 0; i < tcinfo.used_len; i++) {
filter_info.kind = tcinfo.handle_array[i].kind;
ret = libbpf_nl_get_filter(sock, nl_pid, dev->ifindex,
tcinfo.handle_array[i].handle,
dump_filter_nlmsg, &filter_info);
if (ret)
goto out;
}
/* root, ingress and egress handle */
handle = TC_H_ROOT;
filter_info.kind = "root";
ret = libbpf_nl_get_filter(sock, nl_pid, dev->ifindex, handle,
dump_filter_nlmsg, &filter_info);
if (ret)
goto out;
handle = TC_H_MAKE(TC_H_CLSACT, TC_H_MIN_INGRESS);
filter_info.kind = "clsact/ingress";
ret = libbpf_nl_get_filter(sock, nl_pid, dev->ifindex, handle,
dump_filter_nlmsg, &filter_info);
if (ret)
goto out;
handle = TC_H_MAKE(TC_H_CLSACT, TC_H_MIN_EGRESS);
filter_info.kind = "clsact/egress";
ret = libbpf_nl_get_filter(sock, nl_pid, dev->ifindex, handle,
dump_filter_nlmsg, &filter_info);
if (ret)
goto out;
out:
free(tcinfo.handle_array);
return 0;
}
static int query_flow_dissector(struct bpf_attach_info *attach_info)
{
__u32 attach_flags;
__u32 prog_ids[1];
__u32 prog_cnt;
int err;
int fd;
fd = open("/proc/self/ns/net", O_RDONLY);
if (fd < 0) {
p_err("can't open /proc/self/ns/net: %d",
strerror(errno));
return -1;
}
prog_cnt = ARRAY_SIZE(prog_ids);
err = bpf_prog_query(fd, BPF_FLOW_DISSECTOR, 0,
&attach_flags, prog_ids, &prog_cnt);
close(fd);
if (err) {
if (errno == EINVAL) {
/* Older kernel's don't support querying
* flow dissector programs.
*/
errno = 0;
return 0;
}
p_err("can't query prog: %s", strerror(errno));
return -1;
}
if (prog_cnt == 1)
attach_info->flow_dissector_id = prog_ids[0];
return 0;
}
static int do_show(int argc, char **argv)
{
struct bpf_attach_info attach_info = {};
int i, sock, ret, filter_idx = -1;
struct bpf_netdev_t dev_array;
unsigned int nl_pid;
char err_buf[256];
if (argc == 2) {
if (strcmp(argv[0], "dev") != 0)
usage();
filter_idx = if_nametoindex(argv[1]);
if (filter_idx == 0) {
fprintf(stderr, "invalid dev name %s\n", argv[1]);
return -1;
}
} else if (argc != 0) {
usage();
}
ret = query_flow_dissector(&attach_info);
if (ret)
return -1;
sock = libbpf_netlink_open(&nl_pid);
if (sock < 0) {
fprintf(stderr, "failed to open netlink sock\n");
return -1;
}
dev_array.devices = NULL;
dev_array.used_len = 0;
dev_array.array_len = 0;
dev_array.filter_idx = filter_idx;
if (json_output)
jsonw_start_array(json_wtr);
NET_START_OBJECT;
NET_START_ARRAY("xdp", "%s:\n");
ret = libbpf_nl_get_link(sock, nl_pid, dump_link_nlmsg, &dev_array);
NET_END_ARRAY("\n");
if (!ret) {
NET_START_ARRAY("tc", "%s:\n");
for (i = 0; i < dev_array.used_len; i++) {
ret = show_dev_tc_bpf(sock, nl_pid,
&dev_array.devices[i]);
if (ret)
break;
}
NET_END_ARRAY("\n");
}
NET_START_ARRAY("flow_dissector", "%s:\n");
if (attach_info.flow_dissector_id > 0)
NET_DUMP_UINT("id", "id %u", attach_info.flow_dissector_id);
NET_END_ARRAY("\n");
NET_END_OBJECT;
if (json_output)
jsonw_end_array(json_wtr);
if (ret) {
if (json_output)
jsonw_null(json_wtr);
libbpf_strerror(ret, err_buf, sizeof(err_buf));
fprintf(stderr, "Error: %s\n", err_buf);
}
free(dev_array.devices);
close(sock);
return ret;
}
static int do_help(int argc, char **argv)
{
if (json_output) {
jsonw_null(json_wtr);
return 0;
}
fprintf(stderr,
"Usage: %s %s { show | list } [dev <devname>]\n"
" %s %s help\n"
"Note: Only xdp and tc attachments are supported now.\n"
" For progs attached to cgroups, use \"bpftool cgroup\"\n"
" to dump program attachments. For program types\n"
" sk_{filter,skb,msg,reuseport} and lwt/seg6, please\n"
" consult iproute2.\n",
bin_name, argv[-2], bin_name, argv[-2]);
return 0;
}
static const struct cmd cmds[] = {
{ "show", do_show },
{ "list", do_show },
{ "help", do_help },
{ 0 }
};
int do_net(int argc, char **argv)
{
return cmd_select(cmds, argc, argv, do_help);
}