tools/bpf: bpftool: add net support

Add "bpftool net" support. Networking devices are enumerated
to dump device index/name associated with xdp progs.

For each networking device, tc classes and qdiscs are enumerated
in order to check their bpf filters.
In addition, root handle and clsact ingress/egress are also checked for
bpf filters.  Not all filter information is printed out. Only ifindex,
kind, filter name, prog_id and tag are printed out, which are good
enough to show attachment information. If the filter action
is a bpf action, its bpf program id, bpf name and tag will be
printed out as well.

For example,
  $ ./bpftool net
  xdp [
  ifindex 2 devname eth0 prog_id 198
  ]
  tc_filters [
  ifindex 2 kind qdisc_htb name prefix_matcher.o:[cls_prefix_matcher_htb]
            prog_id 111727 tag d08fe3b4319bc2fd act []
  ifindex 2 kind qdisc_clsact_ingress name fbflow_icmp
            prog_id 130246 tag 3f265c7f26db62c9 act []
  ifindex 2 kind qdisc_clsact_egress name prefix_matcher.o:[cls_prefix_matcher_clsact]
            prog_id 111726 tag 99a197826974c876
  ifindex 2 kind qdisc_clsact_egress name cls_fg_dscp
            prog_id 108619 tag dc4630674fd72dcc act []
  ifindex 2 kind qdisc_clsact_egress name fbflow_egress
            prog_id 130245 tag 72d2d830d6888d2c
  ]
  $ ./bpftool -jp net
  [{
        "xdp": [{
                "ifindex": 2,
                "devname": "eth0",
                "prog_id": 198
            }
        ],
        "tc_filters": [{
                "ifindex": 2,
                "kind": "qdisc_htb",
                "name": "prefix_matcher.o:[cls_prefix_matcher_htb]",
                "prog_id": 111727,
                "tag": "d08fe3b4319bc2fd",
                "act": []
            },{
                "ifindex": 2,
                "kind": "qdisc_clsact_ingress",
                "name": "fbflow_icmp",
                "prog_id": 130246,
                "tag": "3f265c7f26db62c9",
                "act": []
            },{
                "ifindex": 2,
                "kind": "qdisc_clsact_egress",
                "name": "prefix_matcher.o:[cls_prefix_matcher_clsact]",
                "prog_id": 111726,
                "tag": "99a197826974c876"
            },{
                "ifindex": 2,
                "kind": "qdisc_clsact_egress",
                "name": "cls_fg_dscp",
                "prog_id": 108619,
                "tag": "dc4630674fd72dcc",
                "act": []
            },{
                "ifindex": 2,
                "kind": "qdisc_clsact_egress",
                "name": "fbflow_egress",
                "prog_id": 130245,
                "tag": "72d2d830d6888d2c"
            }
        ]
    }
  ]

Signed-off-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

1 files changed, 181 insertions, 0 deletions

diff --git a/tools/bpf/bpftool/netlink_dumper.c b/tools/bpf/bpftool/netlink_dumper.c
new file mode 100644
index 000000000000..e12494fd1d2e
--- /dev/null
+++ b/tools/bpf/bpftool/netlink_dumper.c
@@ -0,0 +1,181 @@
+// SPDX-License-Identifier: GPL-2.0+
+// Copyright (C) 2018 Facebook
+
+#include <stdlib.h>
+#include <string.h>
+#include <libbpf.h>
+#include <linux/rtnetlink.h>
+#include <linux/tc_act/tc_bpf.h>
+
+#include <nlattr.h>
+#include "main.h"
+#include "netlink_dumper.h"
+
+static void xdp_dump_prog_id(struct nlattr **tb, int attr,
+			     const char *type)
+{
+	if (!tb[attr])
+		return;
+
+	NET_DUMP_UINT(type, nla_getattr_u32(tb[attr]))
+}
+
+static int do_xdp_dump_one(struct nlattr *attr, unsigned int ifindex,
+			   const char *name)
+{
+	struct nlattr *tb[IFLA_XDP_MAX + 1];
+	unsigned char mode;
+
+	if (nla_parse_nested(tb, IFLA_XDP_MAX, attr, NULL) < 0)
+		return -1;
+
+	if (!tb[IFLA_XDP_ATTACHED])
+		return 0;
+
+	mode = nla_getattr_u8(tb[IFLA_XDP_ATTACHED]);
+	if (mode == XDP_ATTACHED_NONE)
+		return 0;
+
+	NET_START_OBJECT;
+	NET_DUMP_UINT("ifindex", ifindex);
+
+	if (name)
+		NET_DUMP_STR("devname", name);
+
+	if (tb[IFLA_XDP_PROG_ID])
+		NET_DUMP_UINT("prog_id", nla_getattr_u32(tb[IFLA_XDP_PROG_ID]));
+
+	if (mode == XDP_ATTACHED_MULTI) {
+		xdp_dump_prog_id(tb, IFLA_XDP_SKB_PROG_ID, "generic_prog_id");
+		xdp_dump_prog_id(tb, IFLA_XDP_DRV_PROG_ID, "drv_prog_id");
+		xdp_dump_prog_id(tb, IFLA_XDP_HW_PROG_ID, "offload_prog_id");
+	}
+
+	NET_END_OBJECT_FINAL;
+	return 0;
+}
+
+int do_xdp_dump(struct ifinfomsg *ifinfo, struct nlattr **tb)
+{
+	if (!tb[IFLA_XDP])
+		return 0;
+
+	return do_xdp_dump_one(tb[IFLA_XDP], ifinfo->ifi_index,
+			       nla_getattr_str(tb[IFLA_IFNAME]));
+}
+
+static char *hexstring_n2a(const unsigned char *str, int len,
+			   char *buf, int blen)
+{
+	char *ptr = buf;
+	int i;
+
+	for (i = 0; i < len; i++) {
+		if (blen < 3)
+			break;
+		sprintf(ptr, "%02x", str[i]);
+		ptr += 2;
+		blen -= 2;
+	}
+	return buf;
+}
+
+static int do_bpf_dump_one_act(struct nlattr *attr)
+{
+	struct nlattr *tb[TCA_ACT_BPF_MAX + 1];
+	char buf[256];
+
+	if (nla_parse_nested(tb, TCA_ACT_BPF_MAX, attr, NULL) < 0)
+		return -LIBBPF_ERRNO__NLPARSE;
+
+	if (!tb[TCA_ACT_BPF_PARMS])
+		return -LIBBPF_ERRNO__NLPARSE;
+
+	NET_START_OBJECT_NESTED2;
+	if (tb[TCA_ACT_BPF_NAME])
+		NET_DUMP_STR("name", nla_getattr_str(tb[TCA_ACT_BPF_NAME]));
+	if (tb[TCA_ACT_BPF_ID])
+		NET_DUMP_UINT("bpf_id", nla_getattr_u32(tb[TCA_ACT_BPF_ID]));
+	if (tb[TCA_ACT_BPF_TAG])
+		NET_DUMP_STR("tag", hexstring_n2a(nla_data(tb[TCA_ACT_BPF_TAG]),
+						  nla_len(tb[TCA_ACT_BPF_TAG]),
+						  buf, sizeof(buf)));
+	NET_END_OBJECT_NESTED;
+	return 0;
+}
+
+static int do_dump_one_act(struct nlattr *attr)
+{
+	struct nlattr *tb[TCA_ACT_MAX + 1];
+
+	if (!attr)
+		return 0;
+
+	if (nla_parse_nested(tb, TCA_ACT_MAX, attr, NULL) < 0)
+		return -LIBBPF_ERRNO__NLPARSE;
+
+	if (tb[TCA_ACT_KIND] && strcmp(nla_data(tb[TCA_ACT_KIND]), "bpf") == 0)
+		return do_bpf_dump_one_act(tb[TCA_ACT_OPTIONS]);
+
+	return 0;
+}
+
+static int do_bpf_act_dump(struct nlattr *attr)
+{
+	struct nlattr *tb[TCA_ACT_MAX_PRIO + 1];
+	int act, ret;
+
+	if (nla_parse_nested(tb, TCA_ACT_MAX_PRIO, attr, NULL) < 0)
+		return -LIBBPF_ERRNO__NLPARSE;
+
+	NET_START_ARRAY("act", "");
+	for (act = 0; act <= TCA_ACT_MAX_PRIO; act++) {
+		ret = do_dump_one_act(tb[act]);
+		if (ret)
+			break;
+	}
+	NET_END_ARRAY(" ");
+
+	return ret;
+}
+
+static int do_bpf_filter_dump(struct nlattr *attr)
+{
+	struct nlattr *tb[TCA_BPF_MAX + 1];
+	char buf[256];
+	int ret;
+
+	if (nla_parse_nested(tb, TCA_BPF_MAX, attr, NULL) < 0)
+		return -LIBBPF_ERRNO__NLPARSE;
+
+	if (tb[TCA_BPF_NAME])
+		NET_DUMP_STR("name", nla_getattr_str(tb[TCA_BPF_NAME]));
+	if (tb[TCA_BPF_ID])
+		NET_DUMP_UINT("prog_id", nla_getattr_u32(tb[TCA_BPF_ID]));
+	if (tb[TCA_BPF_TAG])
+		NET_DUMP_STR("tag", hexstring_n2a(nla_data(tb[TCA_BPF_TAG]),
+						  nla_len(tb[TCA_BPF_TAG]),
+						  buf, sizeof(buf)));
+	if (tb[TCA_BPF_ACT]) {
+		ret = do_bpf_act_dump(tb[TCA_BPF_ACT]);
+		if (ret)
+			return ret;
+	}
+
+	return 0;
+}
+
+int do_filter_dump(struct tcmsg *info, struct nlattr **tb, const char *kind)
+{
+	int ret = 0;
+
+	if (tb[TCA_OPTIONS] && strcmp(nla_data(tb[TCA_KIND]), "bpf") == 0) {
+		NET_START_OBJECT;
+		NET_DUMP_UINT("ifindex", info->tcm_ifindex);
+		NET_DUMP_STR("kind", kind);
+		ret = do_bpf_filter_dump(tb[TCA_OPTIONS]);
+		NET_END_OBJECT_FINAL;
+	}
+
+	return ret;
+}