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linux/tools/bpf/bpftool/net.c
Kuan-Wei Chiu f04e2ad394 bpftool: Fix undefined behavior in qsort(NULL, 0, ...) 
When netfilter has no entry to display, qsort is called with
qsort(NULL, 0, ...). This results in undefined behavior, as UBSan
reports:

net.c:827:2: runtime error: null pointer passed as argument 1, which is declared to never be null

Although the C standard does not explicitly state whether calling qsort
with a NULL pointer when the size is 0 constitutes undefined behavior,
Section 7.1.4 of the C standard (Use of library functions) mentions:

"Each of the following statements applies unless explicitly stated
otherwise in the detailed descriptions that follow: If an argument to a
function has an invalid value (such as a value outside the domain of
the function, or a pointer outside the address space of the program, or
a null pointer, or a pointer to non-modifiable storage when the
corresponding parameter is not const-qualified) or a type (after
promotion) not expected by a function with variable number of
arguments, the behavior is undefined."

To avoid this, add an early return when nf_link_info is NULL to prevent
calling qsort with a NULL pointer.

Signed-off-by: Kuan-Wei Chiu <visitorckw@gmail.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Reviewed-by: Quentin Monnet <qmo@kernel.org>
Link: https://lore.kernel.org/bpf/20240910150207.3179306-1-visitorckw@gmail.com
2024-09-10 11:40:55 -07:00

1018 lines
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// SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
// Copyright (C) 2018 Facebook
#ifndef _GNU_SOURCE
#define _GNU_SOURCE
#endif
#include <errno.h>
#include <fcntl.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>
#include <unistd.h>
#include <bpf/bpf.h>
#include <bpf/libbpf.h>
#include <net/if.h>
#include <linux/rtnetlink.h>
#include <linux/socket.h>
#include <linux/tc_act/tc_bpf.h>
#include <sys/socket.h>
#include <sys/stat.h>
#include <sys/types.h>
#include "bpf/nlattr.h"
#include "main.h"
#include "netlink_dumper.h"
#ifndef SOL_NETLINK
#define SOL_NETLINK 270
#endif
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;
};
enum net_attach_type {
NET_ATTACH_TYPE_XDP,
NET_ATTACH_TYPE_XDP_GENERIC,
NET_ATTACH_TYPE_XDP_DRIVER,
NET_ATTACH_TYPE_XDP_OFFLOAD,
NET_ATTACH_TYPE_TCX_INGRESS,
NET_ATTACH_TYPE_TCX_EGRESS,
};
static const char * const attach_type_strings[] = {
[NET_ATTACH_TYPE_XDP] = "xdp",
[NET_ATTACH_TYPE_XDP_GENERIC] = "xdpgeneric",
[NET_ATTACH_TYPE_XDP_DRIVER] = "xdpdrv",
[NET_ATTACH_TYPE_XDP_OFFLOAD] = "xdpoffload",
[NET_ATTACH_TYPE_TCX_INGRESS] = "tcx_ingress",
[NET_ATTACH_TYPE_TCX_EGRESS] = "tcx_egress",
};
static const char * const attach_loc_strings[] = {
[BPF_TCX_INGRESS] = "tcx/ingress",
[BPF_TCX_EGRESS] = "tcx/egress",
[BPF_NETKIT_PRIMARY] = "netkit/primary",
[BPF_NETKIT_PEER] = "netkit/peer",
};
const size_t net_attach_type_size = ARRAY_SIZE(attach_type_strings);
static enum net_attach_type parse_attach_type(const char *str)
{
enum net_attach_type type;
for (type = 0; type < net_attach_type_size; type++) {
if (attach_type_strings[type] &&
is_prefix(str, attach_type_strings[type]))
return type;
}
return net_attach_type_size;
}
typedef int (*dump_nlmsg_t)(void *cookie, void *msg, struct nlattr **tb);
typedef int (*__dump_nlmsg_t)(struct nlmsghdr *nlmsg, dump_nlmsg_t, void *cookie);
static int netlink_open(__u32 *nl_pid)
{
struct sockaddr_nl sa;
socklen_t addrlen;
int one = 1, ret;
int sock;
memset(&sa, 0, sizeof(sa));
sa.nl_family = AF_NETLINK;
sock = socket(AF_NETLINK, SOCK_RAW, NETLINK_ROUTE);
if (sock < 0)
return -errno;
if (setsockopt(sock, SOL_NETLINK, NETLINK_EXT_ACK,
&one, sizeof(one)) < 0) {
p_err("Netlink error reporting not supported");
}
if (bind(sock, (struct sockaddr *)&sa, sizeof(sa)) < 0) {
ret = -errno;
goto cleanup;
}
addrlen = sizeof(sa);
if (getsockname(sock, (struct sockaddr *)&sa, &addrlen) < 0) {
ret = -errno;
goto cleanup;
}
if (addrlen != sizeof(sa)) {
ret = -LIBBPF_ERRNO__INTERNAL;
goto cleanup;
}
*nl_pid = sa.nl_pid;
return sock;
cleanup:
close(sock);
return ret;
}
static int netlink_recv(int sock, __u32 nl_pid, __u32 seq,
__dump_nlmsg_t _fn, dump_nlmsg_t fn,
void *cookie)
{
bool multipart = true;
struct nlmsgerr *err;
struct nlmsghdr *nh;
char buf[4096];
int len, ret;
while (multipart) {
multipart = false;
len = recv(sock, buf, sizeof(buf), 0);
if (len < 0) {
ret = -errno;
goto done;
}
if (len == 0)
break;
for (nh = (struct nlmsghdr *)buf; NLMSG_OK(nh, (unsigned int)len);
nh = NLMSG_NEXT(nh, len)) {
if (nh->nlmsg_pid != nl_pid) {
ret = -LIBBPF_ERRNO__WRNGPID;
goto done;
}
if (nh->nlmsg_seq != seq) {
ret = -LIBBPF_ERRNO__INVSEQ;
goto done;
}
if (nh->nlmsg_flags & NLM_F_MULTI)
multipart = true;
switch (nh->nlmsg_type) {
case NLMSG_ERROR:
err = (struct nlmsgerr *)NLMSG_DATA(nh);
if (!err->error)
continue;
ret = err->error;
libbpf_nla_dump_errormsg(nh);
goto done;
case NLMSG_DONE:
return 0;
default:
break;
}
if (_fn) {
ret = _fn(nh, fn, cookie);
if (ret)
return ret;
}
}
}
ret = 0;
done:
return ret;
}
static int __dump_class_nlmsg(struct nlmsghdr *nlh,
dump_nlmsg_t dump_class_nlmsg,
void *cookie)
{
struct nlattr *tb[TCA_MAX + 1], *attr;
struct tcmsg *t = NLMSG_DATA(nlh);
int len;
len = nlh->nlmsg_len - NLMSG_LENGTH(sizeof(*t));
attr = (struct nlattr *) ((void *) t + NLMSG_ALIGN(sizeof(*t)));
if (libbpf_nla_parse(tb, TCA_MAX, attr, len, NULL) != 0)
return -LIBBPF_ERRNO__NLPARSE;
return dump_class_nlmsg(cookie, t, tb);
}
static int netlink_get_class(int sock, unsigned int nl_pid, int ifindex,
dump_nlmsg_t dump_class_nlmsg, void *cookie)
{
struct {
struct nlmsghdr nlh;
struct tcmsg t;
} req = {
.nlh.nlmsg_len = NLMSG_LENGTH(sizeof(struct tcmsg)),
.nlh.nlmsg_type = RTM_GETTCLASS,
.nlh.nlmsg_flags = NLM_F_DUMP | NLM_F_REQUEST,
.t.tcm_family = AF_UNSPEC,
.t.tcm_ifindex = ifindex,
};
int seq = time(NULL);
req.nlh.nlmsg_seq = seq;
if (send(sock, &req, req.nlh.nlmsg_len, 0) < 0)
return -errno;
return netlink_recv(sock, nl_pid, seq, __dump_class_nlmsg,
dump_class_nlmsg, cookie);
}
static int __dump_qdisc_nlmsg(struct nlmsghdr *nlh,
dump_nlmsg_t dump_qdisc_nlmsg,
void *cookie)
{
struct nlattr *tb[TCA_MAX + 1], *attr;
struct tcmsg *t = NLMSG_DATA(nlh);
int len;
len = nlh->nlmsg_len - NLMSG_LENGTH(sizeof(*t));
attr = (struct nlattr *) ((void *) t + NLMSG_ALIGN(sizeof(*t)));
if (libbpf_nla_parse(tb, TCA_MAX, attr, len, NULL) != 0)
return -LIBBPF_ERRNO__NLPARSE;
return dump_qdisc_nlmsg(cookie, t, tb);
}
static int netlink_get_qdisc(int sock, unsigned int nl_pid, int ifindex,
dump_nlmsg_t dump_qdisc_nlmsg, void *cookie)
{
struct {
struct nlmsghdr nlh;
struct tcmsg t;
} req = {
.nlh.nlmsg_len = NLMSG_LENGTH(sizeof(struct tcmsg)),
.nlh.nlmsg_type = RTM_GETQDISC,
.nlh.nlmsg_flags = NLM_F_DUMP | NLM_F_REQUEST,
.t.tcm_family = AF_UNSPEC,
.t.tcm_ifindex = ifindex,
};
int seq = time(NULL);
req.nlh.nlmsg_seq = seq;
if (send(sock, &req, req.nlh.nlmsg_len, 0) < 0)
return -errno;
return netlink_recv(sock, nl_pid, seq, __dump_qdisc_nlmsg,
dump_qdisc_nlmsg, cookie);
}
static int __dump_filter_nlmsg(struct nlmsghdr *nlh,
dump_nlmsg_t dump_filter_nlmsg,
void *cookie)
{
struct nlattr *tb[TCA_MAX + 1], *attr;
struct tcmsg *t = NLMSG_DATA(nlh);
int len;
len = nlh->nlmsg_len - NLMSG_LENGTH(sizeof(*t));
attr = (struct nlattr *) ((void *) t + NLMSG_ALIGN(sizeof(*t)));
if (libbpf_nla_parse(tb, TCA_MAX, attr, len, NULL) != 0)
return -LIBBPF_ERRNO__NLPARSE;
return dump_filter_nlmsg(cookie, t, tb);
}
static int netlink_get_filter(int sock, unsigned int nl_pid, int ifindex, int handle,
dump_nlmsg_t dump_filter_nlmsg, void *cookie)
{
struct {
struct nlmsghdr nlh;
struct tcmsg t;
} req = {
.nlh.nlmsg_len = NLMSG_LENGTH(sizeof(struct tcmsg)),
.nlh.nlmsg_type = RTM_GETTFILTER,
.nlh.nlmsg_flags = NLM_F_DUMP | NLM_F_REQUEST,
.t.tcm_family = AF_UNSPEC,
.t.tcm_ifindex = ifindex,
.t.tcm_parent = handle,
};
int seq = time(NULL);
req.nlh.nlmsg_seq = seq;
if (send(sock, &req, req.nlh.nlmsg_len, 0) < 0)
return -errno;
return netlink_recv(sock, nl_pid, seq, __dump_filter_nlmsg,
dump_filter_nlmsg, cookie);
}
static int __dump_link_nlmsg(struct nlmsghdr *nlh,
dump_nlmsg_t dump_link_nlmsg, void *cookie)
{
struct nlattr *tb[IFLA_MAX + 1], *attr;
struct ifinfomsg *ifi = NLMSG_DATA(nlh);
int len;
len = nlh->nlmsg_len - NLMSG_LENGTH(sizeof(*ifi));
attr = (struct nlattr *) ((void *) ifi + NLMSG_ALIGN(sizeof(*ifi)));
if (libbpf_nla_parse(tb, IFLA_MAX, attr, len, NULL) != 0)
return -LIBBPF_ERRNO__NLPARSE;
return dump_link_nlmsg(cookie, ifi, tb);
}
static int netlink_get_link(int sock, unsigned int nl_pid,
dump_nlmsg_t dump_link_nlmsg, void *cookie)
{
struct {
struct nlmsghdr nlh;
struct ifinfomsg ifm;
} req = {
.nlh.nlmsg_len = NLMSG_LENGTH(sizeof(struct ifinfomsg)),
.nlh.nlmsg_type = RTM_GETLINK,
.nlh.nlmsg_flags = NLM_F_DUMP | NLM_F_REQUEST,
.ifm.ifi_family = AF_PACKET,
};
int seq = time(NULL);
req.nlh.nlmsg_seq = seq;
if (send(sock, &req, req.nlh.nlmsg_len, 0) < 0)
return -errno;
return netlink_recv(sock, nl_pid, seq, __dump_link_nlmsg,
dump_link_nlmsg, cookie);
}
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_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] & (1U << j)))
continue;
NET_DUMP_UINT_ONLY(1U << 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] & (1U << j)))
continue;
NET_DUMP_UINT_ONLY(1U << 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);
__show_dev_tc_bpf(dev, BPF_NETKIT_PRIMARY);
__show_dev_tc_bpf(dev, BPF_NETKIT_PEER);
}
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;
int i, handle, ret = 0;
tcinfo.handle_array = NULL;
tcinfo.used_len = 0;
tcinfo.array_len = 0;
tcinfo.is_qdisc = false;
ret = netlink_get_class(sock, nl_pid, dev->ifindex,
dump_class_qdisc_nlmsg, &tcinfo);
if (ret)
goto out;
tcinfo.is_qdisc = true;
ret = netlink_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 = netlink_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 = netlink_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 = netlink_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 = netlink_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: %s",
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 net_parse_dev(int *argc, char ***argv)
{
int ifindex;
if (is_prefix(**argv, "dev")) {
NEXT_ARGP();
ifindex = if_nametoindex(**argv);
if (!ifindex)
p_err("invalid devname %s", **argv);
NEXT_ARGP();
} else {
p_err("expected 'dev', got: '%s'?", **argv);
return -1;
}
return ifindex;
}
static int do_attach_detach_xdp(int progfd, enum net_attach_type attach_type,
int ifindex, bool overwrite)
{
__u32 flags = 0;
if (!overwrite)
flags = XDP_FLAGS_UPDATE_IF_NOEXIST;
if (attach_type == NET_ATTACH_TYPE_XDP_GENERIC)
flags |= XDP_FLAGS_SKB_MODE;
if (attach_type == NET_ATTACH_TYPE_XDP_DRIVER)
flags |= XDP_FLAGS_DRV_MODE;
if (attach_type == NET_ATTACH_TYPE_XDP_OFFLOAD)
flags |= XDP_FLAGS_HW_MODE;
return bpf_xdp_attach(ifindex, progfd, flags, NULL);
}
static int get_tcx_type(enum net_attach_type attach_type)
{
switch (attach_type) {
case NET_ATTACH_TYPE_TCX_INGRESS:
return BPF_TCX_INGRESS;
case NET_ATTACH_TYPE_TCX_EGRESS:
return BPF_TCX_EGRESS;
default:
return -1;
}
}
static int do_attach_tcx(int progfd, enum net_attach_type attach_type, int ifindex)
{
int type = get_tcx_type(attach_type);
return bpf_prog_attach(progfd, ifindex, type, 0);
}
static int do_detach_tcx(int targetfd, enum net_attach_type attach_type)
{
int type = get_tcx_type(attach_type);
return bpf_prog_detach(targetfd, type);
}
static int do_attach(int argc, char **argv)
{
enum net_attach_type attach_type;
int progfd, ifindex, err = 0;
bool overwrite = false;
/* parse attach args */
if (!REQ_ARGS(5))
return -EINVAL;
attach_type = parse_attach_type(*argv);
if (attach_type == net_attach_type_size) {
p_err("invalid net attach/detach type: %s", *argv);
return -EINVAL;
}
NEXT_ARG();
progfd = prog_parse_fd(&argc, &argv);
if (progfd < 0)
return -EINVAL;
ifindex = net_parse_dev(&argc, &argv);
if (ifindex < 1) {
err = -EINVAL;
goto cleanup;
}
if (argc) {
if (is_prefix(*argv, "overwrite")) {
overwrite = true;
} else {
p_err("expected 'overwrite', got: '%s'?", *argv);
err = -EINVAL;
goto cleanup;
}
}
switch (attach_type) {
/* attach xdp prog */
case NET_ATTACH_TYPE_XDP:
case NET_ATTACH_TYPE_XDP_GENERIC:
case NET_ATTACH_TYPE_XDP_DRIVER:
case NET_ATTACH_TYPE_XDP_OFFLOAD:
err = do_attach_detach_xdp(progfd, attach_type, ifindex, overwrite);
break;
/* attach tcx prog */
case NET_ATTACH_TYPE_TCX_INGRESS:
case NET_ATTACH_TYPE_TCX_EGRESS:
err = do_attach_tcx(progfd, attach_type, ifindex);
break;
default:
break;
}
if (err) {
p_err("interface %s attach failed: %s",
attach_type_strings[attach_type], strerror(-err));
goto cleanup;
}
if (json_output)
jsonw_null(json_wtr);
cleanup:
close(progfd);
return err;
}
static int do_detach(int argc, char **argv)
{
enum net_attach_type attach_type;
int progfd, ifindex, err = 0;
/* parse detach args */
if (!REQ_ARGS(3))
return -EINVAL;
attach_type = parse_attach_type(*argv);
if (attach_type == net_attach_type_size) {
p_err("invalid net attach/detach type: %s", *argv);
return -EINVAL;
}
NEXT_ARG();
ifindex = net_parse_dev(&argc, &argv);
if (ifindex < 1)
return -EINVAL;
switch (attach_type) {
/* detach xdp prog */
case NET_ATTACH_TYPE_XDP:
case NET_ATTACH_TYPE_XDP_GENERIC:
case NET_ATTACH_TYPE_XDP_DRIVER:
case NET_ATTACH_TYPE_XDP_OFFLOAD:
progfd = -1;
err = do_attach_detach_xdp(progfd, attach_type, ifindex, NULL);
break;
/* detach tcx prog */
case NET_ATTACH_TYPE_TCX_INGRESS:
case NET_ATTACH_TYPE_TCX_EGRESS:
err = do_detach_tcx(ifindex, attach_type);
break;
default:
break;
}
if (err < 0) {
p_err("interface %s detach failed: %s",
attach_type_strings[attach_type], strerror(-err));
return err;
}
if (json_output)
jsonw_null(json_wtr);
return 0;
}
static int netfilter_link_compar(const void *a, const void *b)
{
const struct bpf_link_info *nfa = a;
const struct bpf_link_info *nfb = b;
int delta;
delta = nfa->netfilter.pf - nfb->netfilter.pf;
if (delta)
return delta;
delta = nfa->netfilter.hooknum - nfb->netfilter.hooknum;
if (delta)
return delta;
if (nfa->netfilter.priority < nfb->netfilter.priority)
return -1;
if (nfa->netfilter.priority > nfb->netfilter.priority)
return 1;
return nfa->netfilter.flags - nfb->netfilter.flags;
}
static void show_link_netfilter(void)
{
unsigned int nf_link_len = 0, nf_link_count = 0;
struct bpf_link_info *nf_link_info = NULL;
__u32 id = 0;
while (true) {
struct bpf_link_info info;
int fd, err;
__u32 len;
err = bpf_link_get_next_id(id, &id);
if (err) {
if (errno == ENOENT)
break;
p_err("can't get next link: %s (id %d)", strerror(errno), id);
break;
}
fd = bpf_link_get_fd_by_id(id);
if (fd < 0) {
p_err("can't get link by id (%u): %s", id, strerror(errno));
continue;
}
memset(&info, 0, sizeof(info));
len = sizeof(info);
err = bpf_link_get_info_by_fd(fd, &info, &len);
close(fd);
if (err) {
p_err("can't get link info for fd %d: %s", fd, strerror(errno));
continue;
}
if (info.type != BPF_LINK_TYPE_NETFILTER)
continue;
if (nf_link_count >= nf_link_len) {
static const unsigned int max_link_count = INT_MAX / sizeof(info);
struct bpf_link_info *expand;
if (nf_link_count > max_link_count) {
p_err("cannot handle more than %u links\n", max_link_count);
break;
}
nf_link_len += 16;
expand = realloc(nf_link_info, nf_link_len * sizeof(info));
if (!expand) {
p_err("realloc: %s", strerror(errno));
break;
}
nf_link_info = expand;
}
nf_link_info[nf_link_count] = info;
nf_link_count++;
}
if (!nf_link_info)
return;
qsort(nf_link_info, nf_link_count, sizeof(*nf_link_info), netfilter_link_compar);
for (id = 0; id < nf_link_count; id++) {
NET_START_OBJECT;
if (json_output)
netfilter_dump_json(&nf_link_info[id], json_wtr);
else
netfilter_dump_plain(&nf_link_info[id]);
NET_DUMP_UINT("id", " prog_id %u", nf_link_info[id].prog_id);
NET_END_OBJECT;
}
free(nf_link_info);
}
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 = 0;
char err_buf[256];
if (argc == 2) {
filter_idx = net_parse_dev(&argc, &argv);
if (filter_idx < 1)
return -1;
} else if (argc != 0) {
usage();
}
ret = query_flow_dissector(&attach_info);
if (ret)
return -1;
sock = 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 = netlink_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++) {
show_dev_tc_bpf(&dev_array.devices[i]);
ret = show_dev_tc_bpf_classic(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_START_ARRAY("netfilter", "%s:\n");
show_link_netfilter();
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: %1$s %2$s { show | list } [dev <devname>]\n"
" %1$s %2$s attach ATTACH_TYPE PROG dev <devname> [ overwrite ]\n"
" %1$s %2$s detach ATTACH_TYPE dev <devname>\n"
" %1$s %2$s help\n"
"\n"
" " HELP_SPEC_PROGRAM "\n"
" ATTACH_TYPE := { xdp | xdpgeneric | xdpdrv | xdpoffload | tcx_ingress\n"
" | tcx_egress }\n"
" " HELP_SPEC_OPTIONS " }\n"
"\n"
"Note: Only xdp, tcx, tc, netkit, 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"
" consult iproute2.\n"
"",
bin_name, argv[-2]);
return 0;
}
static const struct cmd cmds[] = {
{ "show", do_show },
{ "list", do_show },
{ "attach", do_attach },
{ "detach", do_detach },
{ "help", do_help },
{ 0 }
};
int do_net(int argc, char **argv)
{
return cmd_select(cmds, argc, argv, do_help);
}
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