kernel_optimize_test/tools/lib/bpf/netlink.c
Maciej Fijalkowski 50db9f0731 libbpf: Add a support for getting xdp prog id on ifindex
Since we have a dedicated netlink attributes for xdp setup on a
particular interface, it is now possible to retrieve the program id that
is currently attached to the interface. The use case is targeted for
sample xdp programs, which will store the program id just after loading
bpf program onto iface. On shutdown, the sample will make sure that it
can unload the program by querying again the iface and verifying that
both program id's matches.

Signed-off-by: Maciej Fijalkowski <maciej.fijalkowski@intel.com>
Reviewed-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
2019-02-01 23:37:51 +01:00

423 lines
9.8 KiB
C

// SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause)
/* Copyright (c) 2018 Facebook */
#include <stdlib.h>
#include <memory.h>
#include <unistd.h>
#include <linux/bpf.h>
#include <linux/rtnetlink.h>
#include <sys/socket.h>
#include <errno.h>
#include <time.h>
#include "bpf.h"
#include "libbpf.h"
#include "nlattr.h"
#ifndef SOL_NETLINK
#define SOL_NETLINK 270
#endif
typedef int (*__dump_nlmsg_t)(struct nlmsghdr *nlmsg, libbpf_dump_nlmsg_t,
void *cookie);
struct xdp_id_md {
int ifindex;
__u32 flags;
__u32 id;
};
int libbpf_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) {
fprintf(stderr, "Netlink error reporting not supported\n");
}
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 bpf_netlink_recv(int sock, __u32 nl_pid, int seq,
__dump_nlmsg_t _fn, libbpf_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, 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;
}
int bpf_set_link_xdp_fd(int ifindex, int fd, __u32 flags)
{
int sock, seq = 0, ret;
struct nlattr *nla, *nla_xdp;
struct {
struct nlmsghdr nh;
struct ifinfomsg ifinfo;
char attrbuf[64];
} req;
__u32 nl_pid;
sock = libbpf_netlink_open(&nl_pid);
if (sock < 0)
return sock;
memset(&req, 0, sizeof(req));
req.nh.nlmsg_len = NLMSG_LENGTH(sizeof(struct ifinfomsg));
req.nh.nlmsg_flags = NLM_F_REQUEST | NLM_F_ACK;
req.nh.nlmsg_type = RTM_SETLINK;
req.nh.nlmsg_pid = 0;
req.nh.nlmsg_seq = ++seq;
req.ifinfo.ifi_family = AF_UNSPEC;
req.ifinfo.ifi_index = ifindex;
/* started nested attribute for XDP */
nla = (struct nlattr *)(((char *)&req)
+ NLMSG_ALIGN(req.nh.nlmsg_len));
nla->nla_type = NLA_F_NESTED | IFLA_XDP;
nla->nla_len = NLA_HDRLEN;
/* add XDP fd */
nla_xdp = (struct nlattr *)((char *)nla + nla->nla_len);
nla_xdp->nla_type = IFLA_XDP_FD;
nla_xdp->nla_len = NLA_HDRLEN + sizeof(int);
memcpy((char *)nla_xdp + NLA_HDRLEN, &fd, sizeof(fd));
nla->nla_len += nla_xdp->nla_len;
/* if user passed in any flags, add those too */
if (flags) {
nla_xdp = (struct nlattr *)((char *)nla + nla->nla_len);
nla_xdp->nla_type = IFLA_XDP_FLAGS;
nla_xdp->nla_len = NLA_HDRLEN + sizeof(flags);
memcpy((char *)nla_xdp + NLA_HDRLEN, &flags, sizeof(flags));
nla->nla_len += nla_xdp->nla_len;
}
req.nh.nlmsg_len += NLA_ALIGN(nla->nla_len);
if (send(sock, &req, req.nh.nlmsg_len, 0) < 0) {
ret = -errno;
goto cleanup;
}
ret = bpf_netlink_recv(sock, nl_pid, seq, NULL, NULL, NULL);
cleanup:
close(sock);
return ret;
}
static int __dump_link_nlmsg(struct nlmsghdr *nlh,
libbpf_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 unsigned char get_xdp_id_attr(unsigned char mode, __u32 flags)
{
if (mode != XDP_ATTACHED_MULTI)
return IFLA_XDP_PROG_ID;
if (flags & XDP_FLAGS_DRV_MODE)
return IFLA_XDP_DRV_PROG_ID;
if (flags & XDP_FLAGS_HW_MODE)
return IFLA_XDP_HW_PROG_ID;
if (flags & XDP_FLAGS_SKB_MODE)
return IFLA_XDP_SKB_PROG_ID;
return IFLA_XDP_UNSPEC;
}
static int get_xdp_id(void *cookie, void *msg, struct nlattr **tb)
{
struct nlattr *xdp_tb[IFLA_XDP_MAX + 1];
struct xdp_id_md *xdp_id = cookie;
struct ifinfomsg *ifinfo = msg;
unsigned char mode, xdp_attr;
int ret;
if (xdp_id->ifindex && xdp_id->ifindex != ifinfo->ifi_index)
return 0;
if (!tb[IFLA_XDP])
return 0;
ret = libbpf_nla_parse_nested(xdp_tb, IFLA_XDP_MAX, tb[IFLA_XDP], NULL);
if (ret)
return ret;
if (!xdp_tb[IFLA_XDP_ATTACHED])
return 0;
mode = libbpf_nla_getattr_u8(xdp_tb[IFLA_XDP_ATTACHED]);
if (mode == XDP_ATTACHED_NONE)
return 0;
xdp_attr = get_xdp_id_attr(mode, xdp_id->flags);
if (!xdp_attr || !xdp_tb[xdp_attr])
return 0;
xdp_id->id = libbpf_nla_getattr_u32(xdp_tb[xdp_attr]);
return 0;
}
int bpf_get_link_xdp_id(int ifindex, __u32 *prog_id, __u32 flags)
{
struct xdp_id_md xdp_id = {};
int sock, ret;
__u32 nl_pid;
__u32 mask;
if (flags & ~XDP_FLAGS_MASK)
return -EINVAL;
/* Check whether the single {HW,DRV,SKB} mode is set */
flags &= (XDP_FLAGS_SKB_MODE | XDP_FLAGS_DRV_MODE | XDP_FLAGS_HW_MODE);
mask = flags - 1;
if (flags && flags & mask)
return -EINVAL;
sock = libbpf_netlink_open(&nl_pid);
if (sock < 0)
return sock;
xdp_id.ifindex = ifindex;
xdp_id.flags = flags;
ret = libbpf_nl_get_link(sock, nl_pid, get_xdp_id, &xdp_id);
if (!ret)
*prog_id = xdp_id.id;
close(sock);
return ret;
}
int libbpf_nl_get_link(int sock, unsigned int nl_pid,
libbpf_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 bpf_netlink_recv(sock, nl_pid, seq, __dump_link_nlmsg,
dump_link_nlmsg, cookie);
}
static int __dump_class_nlmsg(struct nlmsghdr *nlh,
libbpf_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);
}
int libbpf_nl_get_class(int sock, unsigned int nl_pid, int ifindex,
libbpf_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 bpf_netlink_recv(sock, nl_pid, seq, __dump_class_nlmsg,
dump_class_nlmsg, cookie);
}
static int __dump_qdisc_nlmsg(struct nlmsghdr *nlh,
libbpf_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);
}
int libbpf_nl_get_qdisc(int sock, unsigned int nl_pid, int ifindex,
libbpf_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 bpf_netlink_recv(sock, nl_pid, seq, __dump_qdisc_nlmsg,
dump_qdisc_nlmsg, cookie);
}
static int __dump_filter_nlmsg(struct nlmsghdr *nlh,
libbpf_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);
}
int libbpf_nl_get_filter(int sock, unsigned int nl_pid, int ifindex, int handle,
libbpf_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 bpf_netlink_recv(sock, nl_pid, seq, __dump_filter_nlmsg,
dump_filter_nlmsg, cookie);
}