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bpftool: Extend net dump with tcx progs
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Add support to dump fd-based attach types via bpftool. This includes both
the tc BPF link and attach ops programs. Dumped information contain the
attach location, function entry name, program ID and link ID when applicable.

Example with tc BPF link:

  # ./bpftool net
  xdp:

  tc:
  bond0(4) tcx/ingress cil_from_netdev prog_id 784 link_id 10
  bond0(4) tcx/egress cil_to_netdev prog_id 804 link_id 11

  flow_dissector:

  netfilter:

Example with tc BPF attach ops:

  # ./bpftool net
  xdp:

  tc:
  bond0(4) tcx/ingress cil_from_netdev prog_id 654
  bond0(4) tcx/egress cil_to_netdev prog_id 672

  flow_dissector:

  netfilter:

Currently, permanent flags are not yet supported, so 'unknown' ones are dumped
via NET_DUMP_UINT_ONLY() and once we do have permanent ones, we dump them as
human readable string.

Signed-off-by: Daniel Borkmann <[email protected]>
Reviewed-by: Quentin Monnet <[email protected]>
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@borkmann
borkmann authored and Kernel Patches Daemon committed Jul 19, 2023
1 parent 303704b commit 596a4e9
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Showing 3 changed files with 116 additions and 16 deletions.
26 changes: 15 additions & 11 deletions tools/bpf/bpftool/Documentation/bpftool-net.rst
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Original file line number Diff line number Diff line change
Expand Up @@ -4,7 +4,7 @@
bpftool-net
================
-------------------------------------------------------------------------------
tool for inspection of netdev/tc related bpf prog attachments
tool for inspection of networking related bpf prog attachments
-------------------------------------------------------------------------------

:Manual section: 8
Expand Down Expand Up @@ -37,10 +37,13 @@ DESCRIPTION
**bpftool net { show | list }** [ **dev** *NAME* ]
List bpf program attachments in the kernel networking subsystem.

Currently, only device driver xdp attachments and tc filter
classification/action attachments are implemented, i.e., for
program types **BPF_PROG_TYPE_SCHED_CLS**,
**BPF_PROG_TYPE_SCHED_ACT** and **BPF_PROG_TYPE_XDP**.
Currently, device driver xdp attachments, tcx and old-style tc
classifier/action attachments, flow_dissector as well as netfilter
attachments are implemented, i.e., for
program types **BPF_PROG_TYPE_XDP**, **BPF_PROG_TYPE_SCHED_CLS**,
**BPF_PROG_TYPE_SCHED_ACT**, **BPF_PROG_TYPE_FLOW_DISSECTOR**,
**BPF_PROG_TYPE_NETFILTER**.

For programs attached to a particular cgroup, e.g.,
**BPF_PROG_TYPE_CGROUP_SKB**, **BPF_PROG_TYPE_CGROUP_SOCK**,
**BPF_PROG_TYPE_SOCK_OPS** and **BPF_PROG_TYPE_CGROUP_SOCK_ADDR**,
Expand All @@ -49,12 +52,13 @@ DESCRIPTION
bpf programs, users should consult other tools, e.g., iproute2.

The current output will start with all xdp program attachments, followed by
all tc class/qdisc bpf program attachments. Both xdp programs and
tc programs are ordered based on ifindex number. If multiple bpf
programs attached to the same networking device through **tc filter**,
the order will be first all bpf programs attached to tc classes, then
all bpf programs attached to non clsact qdiscs, and finally all
bpf programs attached to root and clsact qdisc.
all tcx, then tc class/qdisc bpf program attachments, then flow_dissector
and finally netfilter programs. Both xdp programs and tcx/tc programs are
ordered based on ifindex number. If multiple bpf programs attached
to the same networking device through **tc**, the order will be first
all bpf programs attached to tcx, then tc classes, then all bpf programs
attached to non clsact qdiscs, and finally all bpf programs attached
to root and clsact qdisc.

**bpftool** **net attach** *ATTACH_TYPE* *PROG* **dev** *NAME* [ **overwrite** ]
Attach bpf program *PROG* to network interface *NAME* with
Expand Down
98 changes: 93 additions & 5 deletions tools/bpf/bpftool/net.c
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Original file line number Diff line number Diff line change
Expand Up @@ -76,6 +76,11 @@ static const char * const attach_type_strings[] = {
[NET_ATTACH_TYPE_XDP_OFFLOAD] = "xdpoffload",
};

static const char * const attach_loc_strings[] = {
[BPF_TCX_INGRESS] = "tcx/ingress",
[BPF_TCX_EGRESS] = "tcx/egress",
};

const size_t net_attach_type_size = ARRAY_SIZE(attach_type_strings);

static enum net_attach_type parse_attach_type(const char *str)
Expand Down Expand Up @@ -422,8 +427,89 @@ static int dump_filter_nlmsg(void *cookie, void *msg, struct nlattr **tb)
filter_info->devname, filter_info->ifindex);
}

static int show_dev_tc_bpf(int sock, unsigned int nl_pid,
struct ip_devname_ifindex *dev)
static int __show_dev_tc_bpf_name(__u32 id, char *name, size_t len)
{
struct bpf_prog_info info = {};
__u32 ilen = sizeof(info);
int fd, ret;

fd = bpf_prog_get_fd_by_id(id);
if (fd < 0)
return fd;
ret = bpf_obj_get_info_by_fd(fd, &info, &ilen);
if (ret < 0)
goto out;
ret = -ENOENT;
if (info.name[0]) {
get_prog_full_name(&info, fd, name, len);
ret = 0;
}
out:
close(fd);
return ret;
}

static void __show_dev_tc_bpf(const struct ip_devname_ifindex *dev,
const enum bpf_attach_type loc)
{
__u32 prog_flags[64] = {}, link_flags[64] = {}, i, j;
__u32 prog_ids[64] = {}, link_ids[64] = {};
LIBBPF_OPTS(bpf_prog_query_opts, optq);
char prog_name[MAX_PROG_FULL_NAME];
int ret;

optq.prog_ids = prog_ids;
optq.prog_attach_flags = prog_flags;
optq.link_ids = link_ids;
optq.link_attach_flags = link_flags;
optq.count = ARRAY_SIZE(prog_ids);

ret = bpf_prog_query_opts(dev->ifindex, loc, &optq);
if (ret)
return;
for (i = 0; i < optq.count; i++) {
NET_START_OBJECT;
NET_DUMP_STR("devname", "%s", dev->devname);
NET_DUMP_UINT("ifindex", "(%u)", dev->ifindex);
NET_DUMP_STR("kind", " %s", attach_loc_strings[loc]);
ret = __show_dev_tc_bpf_name(prog_ids[i], prog_name,
sizeof(prog_name));
if (!ret)
NET_DUMP_STR("name", " %s", prog_name);
NET_DUMP_UINT("prog_id", " prog_id %u ", prog_ids[i]);
if (prog_flags[i] || json_output) {
NET_START_ARRAY("prog_flags", "%s ");
for (j = 0; prog_flags[i] && j < 32; j++) {
if (!(prog_flags[i] & (1 << j)))
continue;
NET_DUMP_UINT_ONLY(1 << j);
}
NET_END_ARRAY("");
}
if (link_ids[i] || json_output) {
NET_DUMP_UINT("link_id", "link_id %u ", link_ids[i]);
if (link_flags[i] || json_output) {
NET_START_ARRAY("link_flags", "%s ");
for (j = 0; link_flags[i] && j < 32; j++) {
if (!(link_flags[i] & (1 << j)))
continue;
NET_DUMP_UINT_ONLY(1 << j);
}
NET_END_ARRAY("");
}
}
NET_END_OBJECT_FINAL;
}
}

static void show_dev_tc_bpf(struct ip_devname_ifindex *dev)
{
__show_dev_tc_bpf(dev, BPF_TCX_INGRESS);
__show_dev_tc_bpf(dev, BPF_TCX_EGRESS);
}

static int show_dev_tc_bpf_classic(int sock, unsigned int nl_pid,
struct ip_devname_ifindex *dev)
{
struct bpf_filter_t filter_info;
struct bpf_tcinfo_t tcinfo;
Expand Down Expand Up @@ -790,8 +876,9 @@ static int do_show(int argc, char **argv)
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]);
show_dev_tc_bpf(&dev_array.devices[i]);
ret = show_dev_tc_bpf_classic(sock, nl_pid,
&dev_array.devices[i]);
if (ret)
break;
}
Expand Down Expand Up @@ -839,7 +926,8 @@ static int do_help(int argc, char **argv)
" ATTACH_TYPE := { xdp | xdpgeneric | xdpdrv | xdpoffload }\n"
" " HELP_SPEC_OPTIONS " }\n"
"\n"
"Note: Only xdp and tc attachments are supported now.\n"
"Note: Only xdp, tcx, tc, flow_dissector and netfilter attachments\n"
" are currently supported.\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"
Expand Down
8 changes: 8 additions & 0 deletions tools/bpf/bpftool/netlink_dumper.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -76,6 +76,14 @@
fprintf(stdout, fmt_str, val); \
}

#define NET_DUMP_UINT_ONLY(str) \
{ \
if (json_output) \
jsonw_uint(json_wtr, str); \
else \
fprintf(stdout, "%u ", str); \
}

#define NET_DUMP_STR(name, fmt_str, str) \
{ \
if (json_output) \
Expand Down

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