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netlink: remove libmnl requirement 

It turns out that the binary actually gets smaller if we simply inline
the very small parts of libmnl that we need. Since we wind up needing
the mnlg bits anyway, there's little benefit in linking to libmnl.

Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
This commit is contained in:
Jason A. Donenfeld 2020-02-03 16:52:29 +01:00
parent db5cb4f15c
commit ef117a91d1
9 changed files with 792 additions and 375 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

4
README.md
View File

@ -14,9 +14,7 @@ Android.
$ cd src
$ make
On Linux, [`libmnl`](https://netfilter.org/projects/libmnl/index.html) is
required. On Windows, the [MinGW](http://www.mingw.org/) compiler is required.
On other platforms, only a sane libc is required.
There are no dependencies other than a good C compiler and a sane libc.
## Installing

6
src/Makefile
View File

@ -50,12 +50,6 @@ WIREGUARD_TOOLS_VERSION = $(patsubst v%,%,$(shell GIT_CEILING_DIRECTORIES="$(PWD
ifneq ($(WIREGUARD_TOOLS_VERSION),)
CFLAGS += -D'WIREGUARD_TOOLS_VERSION="$(WIREGUARD_TOOLS_VERSION)"'
endif
ifeq ($(PLATFORM),linux)
LIBMNL_CFLAGS := $(shell $(PKG_CONFIG) --cflags libmnl 2>/dev/null)
LIBMNL_LDLIBS := $(shell $(PKG_CONFIG) --libs libmnl 2>/dev/null || echo -lmnl)
CFLAGS += $(LIBMNL_CFLAGS)
LDLIBS += $(LIBMNL_LDLIBS)
endif
ifeq ($(PLATFORM),haiku)
LDLIBS += -lnetwork -lbsd
endif

10
src/fuzz/Makefile
View File

@ -20,13 +20,13 @@ stringlist: stringlist.c ../ipc.c ../curve25519.c ../encoding.c
$(CC) $(CFLAGS) -o $@ $<
cmd: cmd.c $(wildcard ../*.c)
$(CC) $(CFLAGS) -D'RUNSTATEDIR="/var/empty"' -D'main(a,b)=wg_main(a,b)' -o $@ $^ -lmnl
$(CC) $(CFLAGS) -D'RUNSTATEDIR="/var/empty"' -D'main(a,b)=wg_main(a,b)' -o $@ $^
set: set.c ../set.c ../ipc.c ../encoding.c ../mnlg.c ../curve25519.c ../config.c
$(CC) $(CFLAGS) -o $@ $< -lmnl
set: set.c ../set.c ../ipc.c ../encoding.c ../curve25519.c ../config.c
$(CC) $(CFLAGS) -o $@ $<
setconf: setconf.c ../setconf.c ../ipc.c ../encoding.c ../mnlg.c ../curve25519.c ../config.c
$(CC) $(CFLAGS) -o $@ $< -lmnl
setconf: setconf.c ../setconf.c ../ipc.c ../encoding.c ../curve25519.c ../config.c
$(CC) $(CFLAGS) -o $@ $<
clean:
$(RM) $(FUZZERS)

1
src/fuzz/set.c
View File

@ -15,7 +15,6 @@
static FILE *hacked_fopen(const char *pathname, const char *mode);
#define fopen hacked_fopen
#include "../config.c"
#include "../mnlg.c"
#include "../set.c"
#undef stderr

1
src/fuzz/setconf.c
View File

@ -13,7 +13,6 @@
#undef parse_allowedips
#include "../encoding.c"
#include "../config.c"
#include "../mnlg.c"
static FILE *hacked_fopen(const char *pathname, const char *mode);
#define fopen hacked_fopen
#include "../setconf.c"

5
src/ipc.c
View File

@ -4,13 +4,10 @@
*/
#ifdef __linux__
#include <libmnl/libmnl.h>
#include <linux/if_link.h>
#include <linux/netlink.h>
#include <linux/rtnetlink.h>
#include <linux/genetlink.h>
#include <linux/wireguard.h>
#include "mnlg.h"
#include "netlink.h"
#endif
#include <netinet/in.h>
#include <sys/socket.h>

330
src/mnlg.c
View File

@ -1,330 +0,0 @@
// SPDX-License-Identifier: GPL-2.0
/*
* Copyright (C) 2015-2020 Jason A. Donenfeld <Jason@zx2c4.com>. All Rights Reserved.
*
* Original author: Jiri Pirko <jiri@mellanox.com>
*/
#ifdef __linux__
#include <stdlib.h>
#include <stdbool.h>
#include <string.h>
#include <errno.h>
#include <unistd.h>
#include <time.h>
#include <libmnl/libmnl.h>
#include <linux/genetlink.h>
#include "mnlg.h"
struct mnlg_socket {
struct mnl_socket *nl;
char *buf;
uint16_t id;
uint8_t version;
unsigned int seq;
unsigned int portid;
};
static struct nlmsghdr *__mnlg_msg_prepare(struct mnlg_socket *nlg, uint8_t cmd,
uint16_t flags, uint16_t id,
uint8_t version)
{
struct nlmsghdr *nlh;
struct genlmsghdr *genl;
nlh = mnl_nlmsg_put_header(nlg->buf);
nlh->nlmsg_type = id;
nlh->nlmsg_flags = flags;
nlg->seq = time(NULL);
nlh->nlmsg_seq = nlg->seq;
genl = mnl_nlmsg_put_extra_header(nlh, sizeof(struct genlmsghdr));
genl->cmd = cmd;
genl->version = version;
return nlh;
}
struct nlmsghdr *mnlg_msg_prepare(struct mnlg_socket *nlg, uint8_t cmd,
uint16_t flags)
{
return __mnlg_msg_prepare(nlg, cmd, flags, nlg->id, nlg->version);
}
int mnlg_socket_send(struct mnlg_socket *nlg, const struct nlmsghdr *nlh)
{
return mnl_socket_sendto(nlg->nl, nlh, nlh->nlmsg_len);
}
static int mnlg_cb_noop(const struct nlmsghdr *nlh, void *data)
{
(void)nlh;
(void)data;
return MNL_CB_OK;
}
static int mnlg_cb_error(const struct nlmsghdr *nlh, void *data)
{
const struct nlmsgerr *err = mnl_nlmsg_get_payload(nlh);
(void)data;
if (nlh->nlmsg_len < mnl_nlmsg_size(sizeof(struct nlmsgerr))) {
errno = EBADMSG;
return MNL_CB_ERROR;
}
/* Netlink subsystems returns the errno value with different signess */
if (err->error < 0)
errno = -err->error;
else
errno = err->error;
return err->error == 0 ? MNL_CB_STOP : MNL_CB_ERROR;
}
static int mnlg_cb_stop(const struct nlmsghdr *nlh, void *data)
{
(void)data;
if (nlh->nlmsg_flags & NLM_F_MULTI && nlh->nlmsg_len == mnl_nlmsg_size(sizeof(int))) {
int error = *(int *)mnl_nlmsg_get_payload(nlh);
/* Netlink subsystems returns the errno value with different signess */
if (error < 0)
errno = -error;
else
errno = error;
return error == 0 ? MNL_CB_STOP : MNL_CB_ERROR;
}
return MNL_CB_STOP;
}
static mnl_cb_t mnlg_cb_array[] = {
[NLMSG_NOOP] = mnlg_cb_noop,
[NLMSG_ERROR] = mnlg_cb_error,
[NLMSG_DONE] = mnlg_cb_stop,
[NLMSG_OVERRUN] = mnlg_cb_noop,
};
int mnlg_socket_recv_run(struct mnlg_socket *nlg, mnl_cb_t data_cb, void *data)
{
int err;
do {
err = mnl_socket_recvfrom(nlg->nl, nlg->buf,
MNL_SOCKET_BUFFER_SIZE);
if (err <= 0)
break;
err = mnl_cb_run2(nlg->buf, err, nlg->seq, nlg->portid,
data_cb, data, mnlg_cb_array, MNL_ARRAY_SIZE(mnlg_cb_array));
} while (err > 0);
return err;
}
struct group_info {
bool found;
uint32_t id;
const char *name;
};
static int parse_mc_grps_cb(const struct nlattr *attr, void *data)
{
const struct nlattr **tb = data;
int type = mnl_attr_get_type(attr);
if (mnl_attr_type_valid(attr, CTRL_ATTR_MCAST_GRP_MAX) < 0)
return MNL_CB_OK;
switch (type) {
case CTRL_ATTR_MCAST_GRP_ID:
if (mnl_attr_validate(attr, MNL_TYPE_U32) < 0)
return MNL_CB_ERROR;
break;
case CTRL_ATTR_MCAST_GRP_NAME:
if (mnl_attr_validate(attr, MNL_TYPE_STRING) < 0)
return MNL_CB_ERROR;
break;
}
tb[type] = attr;
return MNL_CB_OK;
}
static void parse_genl_mc_grps(struct nlattr *nested,
struct group_info *group_info)
{
struct nlattr *pos;
const char *name;
mnl_attr_for_each_nested(pos, nested) {
struct nlattr *tb[CTRL_ATTR_MCAST_GRP_MAX + 1] = {};
mnl_attr_parse_nested(pos, parse_mc_grps_cb, tb);
if (!tb[CTRL_ATTR_MCAST_GRP_NAME] ||
!tb[CTRL_ATTR_MCAST_GRP_ID])
continue;
name = mnl_attr_get_str(tb[CTRL_ATTR_MCAST_GRP_NAME]);
if (strcmp(name, group_info->name) != 0)
continue;
group_info->id = mnl_attr_get_u32(tb[CTRL_ATTR_MCAST_GRP_ID]);
group_info->found = true;
}
}
static int get_group_id_attr_cb(const struct nlattr *attr, void *data)
{
const struct nlattr **tb = data;
int type = mnl_attr_get_type(attr);
if (mnl_attr_type_valid(attr, CTRL_ATTR_MAX) < 0)
return MNL_CB_ERROR;
if (type == CTRL_ATTR_MCAST_GROUPS &&
mnl_attr_validate(attr, MNL_TYPE_NESTED) < 0)
return MNL_CB_ERROR;
tb[type] = attr;
return MNL_CB_OK;
}
static int get_group_id_cb(const struct nlmsghdr *nlh, void *data)
{
struct group_info *group_info = data;
struct nlattr *tb[CTRL_ATTR_MAX + 1] = { 0 };
mnl_attr_parse(nlh, sizeof(struct genlmsghdr), get_group_id_attr_cb, tb);
if (!tb[CTRL_ATTR_MCAST_GROUPS])
return MNL_CB_ERROR;
parse_genl_mc_grps(tb[CTRL_ATTR_MCAST_GROUPS], group_info);
return MNL_CB_OK;
}
int mnlg_socket_group_add(struct mnlg_socket *nlg, const char *group_name)
{
struct nlmsghdr *nlh;
struct group_info group_info;
int err;
nlh = __mnlg_msg_prepare(nlg, CTRL_CMD_GETFAMILY,
NLM_F_REQUEST | NLM_F_ACK, GENL_ID_CTRL, 1);
mnl_attr_put_u16(nlh, CTRL_ATTR_FAMILY_ID, nlg->id);
err = mnlg_socket_send(nlg, nlh);
if (err < 0)
return err;
group_info.found = false;
group_info.name = group_name;
err = mnlg_socket_recv_run(nlg, get_group_id_cb, &group_info);
if (err < 0)
return err;
if (!group_info.found) {
errno = ENOENT;
return -1;
}
err = mnl_socket_setsockopt(nlg->nl, NETLINK_ADD_MEMBERSHIP,
&group_info.id, sizeof(group_info.id));
if (err < 0)
return err;
return 0;
}
static int get_family_id_attr_cb(const struct nlattr *attr, void *data)
{
const struct nlattr **tb = data;
int type = mnl_attr_get_type(attr);
if (mnl_attr_type_valid(attr, CTRL_ATTR_MAX) < 0)
return MNL_CB_ERROR;
if (type == CTRL_ATTR_FAMILY_ID &&
mnl_attr_validate(attr, MNL_TYPE_U16) < 0)
return MNL_CB_ERROR;
tb[type] = attr;
return MNL_CB_OK;
}
static int get_family_id_cb(const struct nlmsghdr *nlh, void *data)
{
uint16_t *p_id = data;
struct nlattr *tb[CTRL_ATTR_MAX + 1] = { 0 };
mnl_attr_parse(nlh, sizeof(struct genlmsghdr), get_family_id_attr_cb, tb);
if (!tb[CTRL_ATTR_FAMILY_ID])
return MNL_CB_ERROR;
*p_id = mnl_attr_get_u16(tb[CTRL_ATTR_FAMILY_ID]);
return MNL_CB_OK;
}
struct mnlg_socket *mnlg_socket_open(const char *family_name, uint8_t version)
{
struct mnlg_socket *nlg;
struct nlmsghdr *nlh;
int err;
nlg = malloc(sizeof(*nlg));
if (!nlg)
return NULL;
err = -ENOMEM;
nlg->buf = malloc(MNL_SOCKET_BUFFER_SIZE);
if (!nlg->buf)
goto err_buf_alloc;
nlg->nl = mnl_socket_open(NETLINK_GENERIC);
if (!nlg->nl) {
err = -errno;
goto err_mnl_socket_open;
}
if (mnl_socket_bind(nlg->nl, 0, MNL_SOCKET_AUTOPID) < 0) {
err = -errno;
goto err_mnl_socket_bind;
}
nlg->portid = mnl_socket_get_portid(nlg->nl);
nlh = __mnlg_msg_prepare(nlg, CTRL_CMD_GETFAMILY,
NLM_F_REQUEST | NLM_F_ACK, GENL_ID_CTRL, 1);
mnl_attr_put_strz(nlh, CTRL_ATTR_FAMILY_NAME, family_name);
if (mnlg_socket_send(nlg, nlh) < 0) {
err = -errno;
goto err_mnlg_socket_send;
}
errno = 0;
if (mnlg_socket_recv_run(nlg, get_family_id_cb, &nlg->id) < 0) {
errno = errno == ENOENT ? EPROTONOSUPPORT : errno;
err = errno ? -errno : -ENOSYS;
goto err_mnlg_socket_recv_run;
}
nlg->version = version;
errno = 0;
return nlg;
err_mnlg_socket_recv_run:
err_mnlg_socket_send:
err_mnl_socket_bind:
mnl_socket_close(nlg->nl);
err_mnl_socket_open:
free(nlg->buf);
err_buf_alloc:
free(nlg);
errno = -err;
return NULL;
}
void mnlg_socket_close(struct mnlg_socket *nlg)
{
mnl_socket_close(nlg->nl);
free(nlg->buf);
free(nlg);
}
#endif

25
src/mnlg.h
View File

@ -1,25 +0,0 @@
/* SPDX-License-Identifier: GPL-2.0 */
/*
* Copyright (C) 2015-2020 Jason A. Donenfeld <Jason@zx2c4.com>. All Rights Reserved.
*
* Original author: Jiri Pirko <jiri@mellanox.com>
*/
#ifndef MNLG_H
#define MNLG_H
#ifdef __linux__
#include <libmnl/libmnl.h>
struct mnlg_socket;
struct nlmsghdr *mnlg_msg_prepare(struct mnlg_socket *nlg, uint8_t cmd,
uint16_t flags);
int mnlg_socket_send(struct mnlg_socket *nlg, const struct nlmsghdr *nlh);
int mnlg_socket_recv_run(struct mnlg_socket *nlg, mnl_cb_t data_cb, void *data);
int mnlg_socket_group_add(struct mnlg_socket *nlg, const char *group_name);
struct mnlg_socket *mnlg_socket_open(const char *family_name, uint8_t version);
void mnlg_socket_close(struct mnlg_socket *nlg);
#endif
#endif

785
src/netlink.h Normal file
View File

@ -0,0 +1,785 @@
// SPDX-License-Identifier: LGPL-2.1+
/*
* Copyright (C) 2015-2020 Jason A. Donenfeld <Jason@zx2c4.com>. All Rights Reserved.
* Copyright (C) 2008-2012 Pablo Neira Ayuso <pablo@netfilter.org>.
*/
/* This is a minimized version of libmnl meant to be #include'd */
#include <unistd.h>
#include <stdio.h>
#include <string.h>
#include <stdint.h>
#include <stdbool.h>
#include <stdlib.h>
#include <errno.h>
#include <time.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <linux/netlink.h>
#include <linux/genetlink.h>
#define MNL_SOCKET_AUTOPID 0
#define MNL_SOCKET_BUFFER_SIZE (sysconf(_SC_PAGESIZE) < 8192L ? sysconf(_SC_PAGESIZE) : 8192L)
#define MNL_ALIGNTO 4
#define MNL_ALIGN(len) (((len)+MNL_ALIGNTO-1) & ~(MNL_ALIGNTO-1))
#define MNL_NLMSG_HDRLEN MNL_ALIGN(sizeof(struct nlmsghdr))
#define MNL_ATTR_HDRLEN MNL_ALIGN(sizeof(struct nlattr))
enum mnl_attr_data_type {
MNL_TYPE_UNSPEC,
MNL_TYPE_U8,
MNL_TYPE_U16,
MNL_TYPE_U32,
MNL_TYPE_U64,
MNL_TYPE_STRING,
MNL_TYPE_FLAG,
MNL_TYPE_MSECS,
MNL_TYPE_NESTED,
MNL_TYPE_NESTED_COMPAT,
MNL_TYPE_NUL_STRING,
MNL_TYPE_BINARY,
MNL_TYPE_MAX,
};
#define mnl_attr_for_each(attr, nlh, offset) \
for ((attr) = mnl_nlmsg_get_payload_offset((nlh), (offset)); \
mnl_attr_ok((attr), (char *)mnl_nlmsg_get_payload_tail(nlh) - (char *)(attr)); \
(attr) = mnl_attr_next(attr))
#define mnl_attr_for_each_nested(attr, nest) \
for ((attr) = mnl_attr_get_payload(nest); \
mnl_attr_ok((attr), (char *)mnl_attr_get_payload(nest) + mnl_attr_get_payload_len(nest) - (char *)(attr)); \
(attr) = mnl_attr_next(attr))
#define mnl_attr_for_each_payload(payload, payload_size) \
for ((attr) = (payload); \
mnl_attr_ok((attr), (char *)(payload) + payload_size - (char *)(attr)); \
(attr) = mnl_attr_next(attr))
#define MNL_CB_ERROR -1
#define MNL_CB_STOP 0
#define MNL_CB_OK 1
typedef int (*mnl_attr_cb_t)(const struct nlattr *attr, void *data);
typedef int (*mnl_cb_t)(const struct nlmsghdr *nlh, void *data);
#ifndef MNL_ARRAY_SIZE
#define MNL_ARRAY_SIZE(a) (sizeof(a)/sizeof((a)[0]))
#endif
static size_t mnl_nlmsg_size(size_t len)
{
return len + MNL_NLMSG_HDRLEN;
}
static struct nlmsghdr *mnl_nlmsg_put_header(void *buf)
{
int len = MNL_ALIGN(sizeof(struct nlmsghdr));
struct nlmsghdr *nlh = buf;
memset(buf, 0, len);
nlh->nlmsg_len = len;
return nlh;
}
static void *mnl_nlmsg_put_extra_header(struct nlmsghdr *nlh, size_t size)
{
char *ptr = (char *)nlh + nlh->nlmsg_len;
size_t len = MNL_ALIGN(size);
nlh->nlmsg_len += len;
memset(ptr, 0, len);
return ptr;
}
static void *mnl_nlmsg_get_payload(const struct nlmsghdr *nlh)
{
return (void *)nlh + MNL_NLMSG_HDRLEN;
}
static void *mnl_nlmsg_get_payload_offset(const struct nlmsghdr *nlh, size_t offset)
{
return (void *)nlh + MNL_NLMSG_HDRLEN + MNL_ALIGN(offset);
}
static bool mnl_nlmsg_ok(const struct nlmsghdr *nlh, int len)
{
return len >= (int)sizeof(struct nlmsghdr) &&
nlh->nlmsg_len >= sizeof(struct nlmsghdr) &&
(int)nlh->nlmsg_len <= len;
}
static struct nlmsghdr *mnl_nlmsg_next(const struct nlmsghdr *nlh, int *len)
{
*len -= MNL_ALIGN(nlh->nlmsg_len);
return (struct nlmsghdr *)((void *)nlh + MNL_ALIGN(nlh->nlmsg_len));
}
static void *mnl_nlmsg_get_payload_tail(const struct nlmsghdr *nlh)
{
return (void *)nlh + MNL_ALIGN(nlh->nlmsg_len);
}
static bool mnl_nlmsg_seq_ok(const struct nlmsghdr *nlh, unsigned int seq)
{
return nlh->nlmsg_seq && seq ? nlh->nlmsg_seq == seq : true;
}
static bool mnl_nlmsg_portid_ok(const struct nlmsghdr *nlh, unsigned int portid)
{
return nlh->nlmsg_pid && portid ? nlh->nlmsg_pid == portid : true;
}
static uint16_t mnl_attr_get_type(const struct nlattr *attr)
{
return attr->nla_type & NLA_TYPE_MASK;
}
static uint16_t mnl_attr_get_payload_len(const struct nlattr *attr)
{
return attr->nla_len - MNL_ATTR_HDRLEN;
}
static void *mnl_attr_get_payload(const struct nlattr *attr)
{
return (void *)attr + MNL_ATTR_HDRLEN;
}
static bool mnl_attr_ok(const struct nlattr *attr, int len)
{
return len >= (int)sizeof(struct nlattr) &&
attr->nla_len >= sizeof(struct nlattr) &&
(int)attr->nla_len <= len;
}
static struct nlattr *mnl_attr_next(const struct nlattr *attr)
{
return (struct nlattr *)((void *)attr + MNL_ALIGN(attr->nla_len));
}
static int mnl_attr_type_valid(const struct nlattr *attr, uint16_t max)
{
if (mnl_attr_get_type(attr) > max) {
errno = EOPNOTSUPP;
return -1;
}
return 1;
}
static int __mnl_attr_validate(const struct nlattr *attr,
enum mnl_attr_data_type type, size_t exp_len)
{
uint16_t attr_len = mnl_attr_get_payload_len(attr);
const char *attr_data = mnl_attr_get_payload(attr);
if (attr_len < exp_len) {
errno = ERANGE;
return -1;
}
switch(type) {
case MNL_TYPE_FLAG:
if (attr_len > 0) {
errno = ERANGE;
return -1;
}
break;
case MNL_TYPE_NUL_STRING:
if (attr_len == 0) {
errno = ERANGE;
return -1;
}
if (attr_data[attr_len-1] != '\0') {
errno = EINVAL;
return -1;
}
break;
case MNL_TYPE_STRING:
if (attr_len == 0) {
errno = ERANGE;
return -1;
}
break;
case MNL_TYPE_NESTED:
if (attr_len == 0)
break;
if (attr_len < MNL_ATTR_HDRLEN) {
errno = ERANGE;
return -1;
}
break;
default:
break;
}
if (exp_len && attr_len > exp_len) {
errno = ERANGE;
return -1;
}
return 0;
}
static const size_t mnl_attr_data_type_len[MNL_TYPE_MAX] = {
[MNL_TYPE_U8] = sizeof(uint8_t),
[MNL_TYPE_U16] = sizeof(uint16_t),
[MNL_TYPE_U32] = sizeof(uint32_t),
[MNL_TYPE_U64] = sizeof(uint64_t),
[MNL_TYPE_MSECS] = sizeof(uint64_t),
};
static int mnl_attr_validate(const struct nlattr *attr, enum mnl_attr_data_type type)
{
int exp_len;
if (type >= MNL_TYPE_MAX) {
errno = EINVAL;
return -1;
}
exp_len = mnl_attr_data_type_len[type];
return __mnl_attr_validate(attr, type, exp_len);
}
static int mnl_attr_parse(const struct nlmsghdr *nlh, unsigned int offset,
mnl_attr_cb_t cb, void *data)
{
int ret = MNL_CB_OK;
const struct nlattr *attr;
mnl_attr_for_each(attr, nlh, offset)
if ((ret = cb(attr, data)) <= MNL_CB_STOP)
return ret;
return ret;
}
static int mnl_attr_parse_nested(const struct nlattr *nested, mnl_attr_cb_t cb,
void *data)
{
int ret = MNL_CB_OK;
const struct nlattr *attr;
mnl_attr_for_each_nested(attr, nested)
if ((ret = cb(attr, data)) <= MNL_CB_STOP)
return ret;
return ret;
}
static uint8_t mnl_attr_get_u8(const struct nlattr *attr)
{
return *((uint8_t *)mnl_attr_get_payload(attr));
}
static uint16_t mnl_attr_get_u16(const struct nlattr *attr)
{
return *((uint16_t *)mnl_attr_get_payload(attr));
}
static uint32_t mnl_attr_get_u32(const struct nlattr *attr)
{
return *((uint32_t *)mnl_attr_get_payload(attr));
}
static uint64_t mnl_attr_get_u64(const struct nlattr *attr)
{
uint64_t tmp;
memcpy(&tmp, mnl_attr_get_payload(attr), sizeof(tmp));
return tmp;
}
static const char *mnl_attr_get_str(const struct nlattr *attr)
{
return mnl_attr_get_payload(attr);
}
static void mnl_attr_put(struct nlmsghdr *nlh, uint16_t type, size_t len,
const void *data)
{
struct nlattr *attr = mnl_nlmsg_get_payload_tail(nlh);
uint16_t payload_len = MNL_ALIGN(sizeof(struct nlattr)) + len;
int pad;
attr->nla_type = type;
attr->nla_len = payload_len;
memcpy(mnl_attr_get_payload(attr), data, len);
nlh->nlmsg_len += MNL_ALIGN(payload_len);
pad = MNL_ALIGN(len) - len;
if (pad > 0)
memset(mnl_attr_get_payload(attr) + len, 0, pad);
}
static void mnl_attr_put_u16(struct nlmsghdr *nlh, uint16_t type, uint16_t data)
{
mnl_attr_put(nlh, type, sizeof(uint16_t), &data);
}
static void mnl_attr_put_u32(struct nlmsghdr *nlh, uint16_t type, uint32_t data)
{
mnl_attr_put(nlh, type, sizeof(uint32_t), &data);
}
static void mnl_attr_put_strz(struct nlmsghdr *nlh, uint16_t type, const char *data)
{
mnl_attr_put(nlh, type, strlen(data)+1, data);
}
static struct nlattr *mnl_attr_nest_start(struct nlmsghdr *nlh, uint16_t type)
{
struct nlattr *start = mnl_nlmsg_get_payload_tail(nlh);
start->nla_type = NLA_F_NESTED | type;
nlh->nlmsg_len += MNL_ALIGN(sizeof(struct nlattr));
return start;
}
static bool mnl_attr_put_check(struct nlmsghdr *nlh, size_t buflen,
uint16_t type, size_t len, const void *data)
{
if (nlh->nlmsg_len + MNL_ATTR_HDRLEN + MNL_ALIGN(len) > buflen)
return false;
mnl_attr_put(nlh, type, len, data);
return true;
}
static bool mnl_attr_put_u8_check(struct nlmsghdr *nlh, size_t buflen,
uint16_t type, uint8_t data)
{
return mnl_attr_put_check(nlh, buflen, type, sizeof(uint8_t), &data);
}
static bool mnl_attr_put_u16_check(struct nlmsghdr *nlh, size_t buflen,
uint16_t type, uint16_t data)
{
return mnl_attr_put_check(nlh, buflen, type, sizeof(uint16_t), &data);
}
static bool mnl_attr_put_u32_check(struct nlmsghdr *nlh, size_t buflen,
uint16_t type, uint32_t data)
{
return mnl_attr_put_check(nlh, buflen, type, sizeof(uint32_t), &data);
}
static struct nlattr *mnl_attr_nest_start_check(struct nlmsghdr *nlh, size_t buflen,
uint16_t type)
{
if (nlh->nlmsg_len + MNL_ATTR_HDRLEN > buflen)
return NULL;
return mnl_attr_nest_start(nlh, type);
}
static void mnl_attr_nest_end(struct nlmsghdr *nlh, struct nlattr *start)
{
start->nla_len = mnl_nlmsg_get_payload_tail(nlh) - (void *)start;
}
static void mnl_attr_nest_cancel(struct nlmsghdr *nlh, struct nlattr *start)
{
nlh->nlmsg_len -= mnl_nlmsg_get_payload_tail(nlh) - (void *)start;
}
static int mnl_cb_noop(__attribute__((unused)) const struct nlmsghdr *nlh, __attribute__((unused)) void *data)
{
return MNL_CB_OK;
}
static int mnl_cb_error(const struct nlmsghdr *nlh, __attribute__((unused)) void *data)
{
const struct nlmsgerr *err = mnl_nlmsg_get_payload(nlh);
if (nlh->nlmsg_len < mnl_nlmsg_size(sizeof(struct nlmsgerr))) {
errno = EBADMSG;
return MNL_CB_ERROR;
}
if (err->error < 0)
errno = -err->error;
else
errno = err->error;
return err->error == 0 ? MNL_CB_STOP : MNL_CB_ERROR;
}
static int mnl_cb_stop(__attribute__((unused)) const struct nlmsghdr *nlh, __attribute__((unused)) void *data)
{
return MNL_CB_STOP;
}
static const mnl_cb_t default_cb_array[NLMSG_MIN_TYPE] = {
[NLMSG_NOOP] = mnl_cb_noop,
[NLMSG_ERROR] = mnl_cb_error,
[NLMSG_DONE] = mnl_cb_stop,
[NLMSG_OVERRUN] = mnl_cb_noop,
};
static int __mnl_cb_run(const void *buf, size_t numbytes,
unsigned int seq, unsigned int portid,
mnl_cb_t cb_data, void *data,
const mnl_cb_t *cb_ctl_array,
unsigned int cb_ctl_array_len)
{
int ret = MNL_CB_OK, len = numbytes;
const struct nlmsghdr *nlh = buf;
while (mnl_nlmsg_ok(nlh, len)) {
if (!mnl_nlmsg_portid_ok(nlh, portid)) {
errno = ESRCH;
return -1;
}
if (!mnl_nlmsg_seq_ok(nlh, seq)) {
errno = EPROTO;
return -1;
}
if (nlh->nlmsg_flags & NLM_F_DUMP_INTR) {
errno = EINTR;
return -1;
}
if (nlh->nlmsg_type >= NLMSG_MIN_TYPE) {
if (cb_data){
ret = cb_data(nlh, data);
if (ret <= MNL_CB_STOP)
goto out;
}
} else if (nlh->nlmsg_type < cb_ctl_array_len) {
if (cb_ctl_array && cb_ctl_array[nlh->nlmsg_type]) {
ret = cb_ctl_array[nlh->nlmsg_type](nlh, data);
if (ret <= MNL_CB_STOP)
goto out;
}
} else if (default_cb_array[nlh->nlmsg_type]) {
ret = default_cb_array[nlh->nlmsg_type](nlh, data);
if (ret <= MNL_CB_STOP)
goto out;
}
nlh = mnl_nlmsg_next(nlh, &len);
}
out:
return ret;
}
static int mnl_cb_run2(const void *buf, size_t numbytes, unsigned int seq,
unsigned int portid, mnl_cb_t cb_data, void *data,
const mnl_cb_t *cb_ctl_array, unsigned int cb_ctl_array_len)
{
return __mnl_cb_run(buf, numbytes, seq, portid, cb_data, data,
cb_ctl_array, cb_ctl_array_len);
}
static int mnl_cb_run(const void *buf, size_t numbytes, unsigned int seq,
unsigned int portid, mnl_cb_t cb_data, void *data)
{
return __mnl_cb_run(buf, numbytes, seq, portid, cb_data, data, NULL, 0);
}
struct mnl_socket {
int fd;
struct sockaddr_nl addr;
};
static unsigned int mnl_socket_get_portid(const struct mnl_socket *nl)
{
return nl->addr.nl_pid;
}
static struct mnl_socket *__mnl_socket_open(int bus, int flags)
{
struct mnl_socket *nl;
nl = calloc(1, sizeof(struct mnl_socket));
if (nl == NULL)
return NULL;
nl->fd = socket(AF_NETLINK, SOCK_RAW | flags, bus);
if (nl->fd == -1) {
free(nl);
return NULL;
}
return nl;
}
static struct mnl_socket *mnl_socket_open(int bus)
{
return __mnl_socket_open(bus, 0);
}
static int mnl_socket_bind(struct mnl_socket *nl, unsigned int groups, pid_t pid)
{
int ret;
socklen_t addr_len;
nl->addr.nl_family = AF_NETLINK;
nl->addr.nl_groups = groups;
nl->addr.nl_pid = pid;
ret = bind(nl->fd, (struct sockaddr *) &nl->addr, sizeof (nl->addr));
if (ret < 0)
return ret;
addr_len = sizeof(nl->addr);
ret = getsockname(nl->fd, (struct sockaddr *) &nl->addr, &addr_len);
if (ret < 0)
return ret;
if (addr_len != sizeof(nl->addr)) {
errno = EINVAL;
return -1;
}
if (nl->addr.nl_family != AF_NETLINK) {
errno = EINVAL;
return -1;
}
return 0;
}
static ssize_t mnl_socket_sendto(const struct mnl_socket *nl, const void *buf,
size_t len)
{
static const struct sockaddr_nl snl = {
.nl_family = AF_NETLINK
};
return sendto(nl->fd, buf, len, 0,
(struct sockaddr *) &snl, sizeof(snl));
}
static ssize_t mnl_socket_recvfrom(const struct mnl_socket *nl, void *buf,
size_t bufsiz)
{
ssize_t ret;
struct sockaddr_nl addr;
struct iovec iov = {
.iov_base = buf,
.iov_len = bufsiz,
};
struct msghdr msg = {
.msg_name = &addr,
.msg_namelen = sizeof(struct sockaddr_nl),
.msg_iov = &iov,
.msg_iovlen = 1,
.msg_control = NULL,
.msg_controllen = 0,
.msg_flags = 0,
};
ret = recvmsg(nl->fd, &msg, 0);
if (ret == -1)
return ret;
if (msg.msg_flags & MSG_TRUNC) {
errno = ENOSPC;
return -1;
}
if (msg.msg_namelen != sizeof(struct sockaddr_nl)) {
errno = EINVAL;
return -1;
}
return ret;
}
static int mnl_socket_close(struct mnl_socket *nl)
{
int ret = close(nl->fd);
free(nl);
return ret;
}
/* This is a wrapper for generic netlink, originally from Jiri Pirko <jiri@mellanox.com>: */
struct mnlg_socket {
struct mnl_socket *nl;
char *buf;
uint16_t id;
uint8_t version;
unsigned int seq;
unsigned int portid;
};
static struct nlmsghdr *__mnlg_msg_prepare(struct mnlg_socket *nlg, uint8_t cmd,
uint16_t flags, uint16_t id,
uint8_t version)
{
struct nlmsghdr *nlh;
struct genlmsghdr *genl;
nlh = mnl_nlmsg_put_header(nlg->buf);
nlh->nlmsg_type = id;
nlh->nlmsg_flags = flags;
nlg->seq = time(NULL);
nlh->nlmsg_seq = nlg->seq;
genl = mnl_nlmsg_put_extra_header(nlh, sizeof(struct genlmsghdr));
genl->cmd = cmd;
genl->version = version;
return nlh;
}
static struct nlmsghdr *mnlg_msg_prepare(struct mnlg_socket *nlg, uint8_t cmd,
uint16_t flags)
{
return __mnlg_msg_prepare(nlg, cmd, flags, nlg->id, nlg->version);
}
static int mnlg_socket_send(struct mnlg_socket *nlg, const struct nlmsghdr *nlh)
{
return mnl_socket_sendto(nlg->nl, nlh, nlh->nlmsg_len);
}
static int mnlg_cb_noop(const struct nlmsghdr *nlh, void *data)
{
(void)nlh;
(void)data;
return MNL_CB_OK;
}
static int mnlg_cb_error(const struct nlmsghdr *nlh, void *data)
{
const struct nlmsgerr *err = mnl_nlmsg_get_payload(nlh);
(void)data;
if (nlh->nlmsg_len < mnl_nlmsg_size(sizeof(struct nlmsgerr))) {
errno = EBADMSG;
return MNL_CB_ERROR;
}
/* Netlink subsystems returns the errno value with different signess */
if (err->error < 0)
errno = -err->error;
else
errno = err->error;
return err->error == 0 ? MNL_CB_STOP : MNL_CB_ERROR;
}
static int mnlg_cb_stop(const struct nlmsghdr *nlh, void *data)
{
(void)data;
if (nlh->nlmsg_flags & NLM_F_MULTI && nlh->nlmsg_len == mnl_nlmsg_size(sizeof(int))) {
int error = *(int *)mnl_nlmsg_get_payload(nlh);
/* Netlink subsystems returns the errno value with different signess */
if (error < 0)
errno = -error;
else
errno = error;
return error == 0 ? MNL_CB_STOP : MNL_CB_ERROR;
}
return MNL_CB_STOP;
}
static const mnl_cb_t mnlg_cb_array[] = {
[NLMSG_NOOP] = mnlg_cb_noop,
[NLMSG_ERROR] = mnlg_cb_error,
[NLMSG_DONE] = mnlg_cb_stop,
[NLMSG_OVERRUN] = mnlg_cb_noop,
};
static int mnlg_socket_recv_run(struct mnlg_socket *nlg, mnl_cb_t data_cb, void *data)
{
int err;
do {
err = mnl_socket_recvfrom(nlg->nl, nlg->buf,
MNL_SOCKET_BUFFER_SIZE);
if (err <= 0)
break;
err = mnl_cb_run2(nlg->buf, err, nlg->seq, nlg->portid,
data_cb, data, mnlg_cb_array, MNL_ARRAY_SIZE(mnlg_cb_array));
} while (err > 0);
return err;
}
static int get_family_id_attr_cb(const struct nlattr *attr, void *data)
{
const struct nlattr **tb = data;
int type = mnl_attr_get_type(attr);
if (mnl_attr_type_valid(attr, CTRL_ATTR_MAX) < 0)
return MNL_CB_ERROR;
if (type == CTRL_ATTR_FAMILY_ID &&
mnl_attr_validate(attr, MNL_TYPE_U16) < 0)
return MNL_CB_ERROR;
tb[type] = attr;
return MNL_CB_OK;
}
static int get_family_id_cb(const struct nlmsghdr *nlh, void *data)
{
uint16_t *p_id = data;
struct nlattr *tb[CTRL_ATTR_MAX + 1] = { 0 };
mnl_attr_parse(nlh, sizeof(struct genlmsghdr), get_family_id_attr_cb, tb);
if (!tb[CTRL_ATTR_FAMILY_ID])
return MNL_CB_ERROR;
*p_id = mnl_attr_get_u16(tb[CTRL_ATTR_FAMILY_ID]);
return MNL_CB_OK;
}
static struct mnlg_socket *mnlg_socket_open(const char *family_name, uint8_t version)
{
struct mnlg_socket *nlg;
struct nlmsghdr *nlh;
int err;
nlg = malloc(sizeof(*nlg));
if (!nlg)
return NULL;
err = -ENOMEM;
nlg->buf = malloc(MNL_SOCKET_BUFFER_SIZE);
if (!nlg->buf)
goto err_buf_alloc;
nlg->nl = mnl_socket_open(NETLINK_GENERIC);
if (!nlg->nl) {
err = -errno;
goto err_mnl_socket_open;
}
if (mnl_socket_bind(nlg->nl, 0, MNL_SOCKET_AUTOPID) < 0) {
err = -errno;
goto err_mnl_socket_bind;
}
nlg->portid = mnl_socket_get_portid(nlg->nl);
nlh = __mnlg_msg_prepare(nlg, CTRL_CMD_GETFAMILY,
NLM_F_REQUEST | NLM_F_ACK, GENL_ID_CTRL, 1);
mnl_attr_put_strz(nlh, CTRL_ATTR_FAMILY_NAME, family_name);
if (mnlg_socket_send(nlg, nlh) < 0) {
err = -errno;
goto err_mnlg_socket_send;
}
errno = 0;
if (mnlg_socket_recv_run(nlg, get_family_id_cb, &nlg->id) < 0) {
errno = errno == ENOENT ? EPROTONOSUPPORT : errno;
err = errno ? -errno : -ENOSYS;
goto err_mnlg_socket_recv_run;
}
nlg->version = version;
errno = 0;
return nlg;
err_mnlg_socket_recv_run:
err_mnlg_socket_send:
err_mnl_socket_bind:
mnl_socket_close(nlg->nl);
err_mnl_socket_open:
free(nlg->buf);
err_buf_alloc:
free(nlg);
errno = -err;
return NULL;
}
static void mnlg_socket_close(struct mnlg_socket *nlg)
{
mnl_socket_close(nlg->nl);
free(nlg->buf);
free(nlg);
}