wireguard-tools/src/ipc-linux.h

520 lines
15 KiB
C++

// SPDX-License-Identifier: MIT
/*
* Copyright (C) 2015-2020 Jason A. Donenfeld <Jason@zx2c4.com>. All Rights Reserved.
*/
#include <stdbool.h>
#include <stddef.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <errno.h>
#include <string.h>
#include <time.h>
#include <sys/socket.h>
#include <sys/types.h>
#include <linux/genetlink.h>
#include <linux/if_link.h>
#include <linux/netlink.h>
#include <linux/rtnetlink.h>
#include <linux/wireguard.h>
#include <netinet/in.h>
#include "containers.h"
#include "encoding.h"
#include "netlink.h"
#define IPC_SUPPORTS_KERNEL_INTERFACE
#define SOCKET_BUFFER_SIZE (mnl_ideal_socket_buffer_size())
struct interface {
const char *name;
bool is_wireguard;
};
static int parse_linkinfo(const struct nlattr *attr, void *data)
{
struct interface *interface = data;
if (mnl_attr_get_type(attr) == IFLA_INFO_KIND && !strcmp(WG_GENL_NAME, mnl_attr_get_str(attr)))
interface->is_wireguard = true;
return MNL_CB_OK;
}
static int parse_infomsg(const struct nlattr *attr, void *data)
{
struct interface *interface = data;
if (mnl_attr_get_type(attr) == IFLA_LINKINFO)
return mnl_attr_parse_nested(attr, parse_linkinfo, data);
else if (mnl_attr_get_type(attr) == IFLA_IFNAME)
interface->name = mnl_attr_get_str(attr);
return MNL_CB_OK;
}
static int read_devices_cb(const struct nlmsghdr *nlh, void *data)
{
struct string_list *list = data;
struct interface interface = { 0 };
int ret;
ret = mnl_attr_parse(nlh, sizeof(struct ifinfomsg), parse_infomsg, &interface);
if (ret != MNL_CB_OK)
return ret;
if (interface.name && interface.is_wireguard)
ret = string_list_add(list, interface.name);
if (ret < 0)
return ret;
if (nlh->nlmsg_type != NLMSG_DONE)
return MNL_CB_OK + 1;
return MNL_CB_OK;
}
static int kernel_get_wireguard_interfaces(struct string_list *list)
{
struct mnl_socket *nl = NULL;
char *rtnl_buffer = NULL;
size_t message_len;
unsigned int portid, seq;
ssize_t len;
int ret = 0;
struct nlmsghdr *nlh;
struct ifinfomsg *ifm;
ret = -ENOMEM;
rtnl_buffer = calloc(SOCKET_BUFFER_SIZE, 1);
if (!rtnl_buffer)
goto cleanup;
nl = mnl_socket_open(NETLINK_ROUTE);
if (!nl) {
ret = -errno;
goto cleanup;
}
if (mnl_socket_bind(nl, 0, MNL_SOCKET_AUTOPID) < 0) {
ret = -errno;
goto cleanup;
}
seq = time(NULL);
portid = mnl_socket_get_portid(nl);
nlh = mnl_nlmsg_put_header(rtnl_buffer);
nlh->nlmsg_type = RTM_GETLINK;
nlh->nlmsg_flags = NLM_F_REQUEST | NLM_F_ACK | NLM_F_DUMP;
nlh->nlmsg_seq = seq;
ifm = mnl_nlmsg_put_extra_header(nlh, sizeof(*ifm));
ifm->ifi_family = AF_UNSPEC;
message_len = nlh->nlmsg_len;
if (mnl_socket_sendto(nl, rtnl_buffer, message_len) < 0) {
ret = -errno;
goto cleanup;
}
another:
if ((len = mnl_socket_recvfrom(nl, rtnl_buffer, SOCKET_BUFFER_SIZE)) < 0) {
ret = -errno;
goto cleanup;
}
if ((len = mnl_cb_run(rtnl_buffer, len, seq, portid, read_devices_cb, list)) < 0) {
/* Netlink returns NLM_F_DUMP_INTR if the set of all tunnels changed
* during the dump. That's unfortunate, but is pretty common on busy
* systems that are adding and removing tunnels all the time. Rather
* than retrying, potentially indefinitely, we just work with the
* partial results. */
if (errno != EINTR) {
ret = -errno;
goto cleanup;
}
}
if (len == MNL_CB_OK + 1)
goto another;
ret = 0;
cleanup:
free(rtnl_buffer);
if (nl)
mnl_socket_close(nl);
return ret;
}
static int kernel_set_device(struct wgdevice *dev)
{
int ret = 0;
struct wgpeer *peer = NULL;
struct wgallowedip *allowedip = NULL;
struct nlattr *peers_nest, *peer_nest, *allowedips_nest, *allowedip_nest;
struct nlmsghdr *nlh;
struct mnlg_socket *nlg;
nlg = mnlg_socket_open(WG_GENL_NAME, WG_GENL_VERSION);
if (!nlg)
return -errno;
again:
nlh = mnlg_msg_prepare(nlg, WG_CMD_SET_DEVICE, NLM_F_REQUEST | NLM_F_ACK);
mnl_attr_put_strz(nlh, WGDEVICE_A_IFNAME, dev->name);
if (!peer) {
uint32_t flags = 0;
if (dev->flags & WGDEVICE_HAS_PRIVATE_KEY)
mnl_attr_put(nlh, WGDEVICE_A_PRIVATE_KEY, sizeof(dev->private_key), dev->private_key);
if (dev->flags & WGDEVICE_HAS_LISTEN_PORT)
mnl_attr_put_u16(nlh, WGDEVICE_A_LISTEN_PORT, dev->listen_port);
if (dev->flags & WGDEVICE_HAS_FWMARK)
mnl_attr_put_u32(nlh, WGDEVICE_A_FWMARK, dev->fwmark);
if (dev->flags & WGDEVICE_REPLACE_PEERS)
flags |= WGDEVICE_F_REPLACE_PEERS;
if (flags)
mnl_attr_put_u32(nlh, WGDEVICE_A_FLAGS, flags);
}
if (!dev->first_peer)
goto send;
peers_nest = peer_nest = allowedips_nest = allowedip_nest = NULL;
peers_nest = mnl_attr_nest_start(nlh, WGDEVICE_A_PEERS);
for (peer = peer ? peer : dev->first_peer; peer; peer = peer->next_peer) {
uint32_t flags = 0;
peer_nest = mnl_attr_nest_start_check(nlh, SOCKET_BUFFER_SIZE, 0);
if (!peer_nest)
goto toobig_peers;
if (!mnl_attr_put_check(nlh, SOCKET_BUFFER_SIZE, WGPEER_A_PUBLIC_KEY, sizeof(peer->public_key), peer->public_key))
goto toobig_peers;
if (peer->flags & WGPEER_REMOVE_ME)
flags |= WGPEER_F_REMOVE_ME;
if (!allowedip) {
if (peer->flags & WGPEER_REPLACE_ALLOWEDIPS)
flags |= WGPEER_F_REPLACE_ALLOWEDIPS;
if (peer->flags & WGPEER_HAS_PRESHARED_KEY) {
if (!mnl_attr_put_check(nlh, SOCKET_BUFFER_SIZE, WGPEER_A_PRESHARED_KEY, sizeof(peer->preshared_key), peer->preshared_key))
goto toobig_peers;
}
if (peer->endpoint.addr.sa_family == AF_INET) {
if (!mnl_attr_put_check(nlh, SOCKET_BUFFER_SIZE, WGPEER_A_ENDPOINT, sizeof(peer->endpoint.addr4), &peer->endpoint.addr4))
goto toobig_peers;
} else if (peer->endpoint.addr.sa_family == AF_INET6) {
if (!mnl_attr_put_check(nlh, SOCKET_BUFFER_SIZE, WGPEER_A_ENDPOINT, sizeof(peer->endpoint.addr6), &peer->endpoint.addr6))
goto toobig_peers;
}
if (peer->flags & WGPEER_HAS_PERSISTENT_KEEPALIVE_INTERVAL) {
if (!mnl_attr_put_u16_check(nlh, SOCKET_BUFFER_SIZE, WGPEER_A_PERSISTENT_KEEPALIVE_INTERVAL, peer->persistent_keepalive_interval))
goto toobig_peers;
}
}
if (flags) {
if (!mnl_attr_put_u32_check(nlh, SOCKET_BUFFER_SIZE, WGPEER_A_FLAGS, flags))
goto toobig_peers;
}
if (peer->first_allowedip) {
if (!allowedip)
allowedip = peer->first_allowedip;
allowedips_nest = mnl_attr_nest_start_check(nlh, SOCKET_BUFFER_SIZE, WGPEER_A_ALLOWEDIPS);
if (!allowedips_nest)
goto toobig_allowedips;
for (; allowedip; allowedip = allowedip->next_allowedip) {
allowedip_nest = mnl_attr_nest_start_check(nlh, SOCKET_BUFFER_SIZE, 0);
if (!allowedip_nest)
goto toobig_allowedips;
if (!mnl_attr_put_u16_check(nlh, SOCKET_BUFFER_SIZE, WGALLOWEDIP_A_FAMILY, allowedip->family))
goto toobig_allowedips;
if (allowedip->family == AF_INET) {
if (!mnl_attr_put_check(nlh, SOCKET_BUFFER_SIZE, WGALLOWEDIP_A_IPADDR, sizeof(allowedip->ip4), &allowedip->ip4))
goto toobig_allowedips;
} else if (allowedip->family == AF_INET6) {
if (!mnl_attr_put_check(nlh, SOCKET_BUFFER_SIZE, WGALLOWEDIP_A_IPADDR, sizeof(allowedip->ip6), &allowedip->ip6))
goto toobig_allowedips;
}
if (!mnl_attr_put_u8_check(nlh, SOCKET_BUFFER_SIZE, WGALLOWEDIP_A_CIDR_MASK, allowedip->cidr))
goto toobig_allowedips;
mnl_attr_nest_end(nlh, allowedip_nest);
allowedip_nest = NULL;
}
mnl_attr_nest_end(nlh, allowedips_nest);
allowedips_nest = NULL;
}
mnl_attr_nest_end(nlh, peer_nest);
peer_nest = NULL;
}
mnl_attr_nest_end(nlh, peers_nest);
peers_nest = NULL;
goto send;
toobig_allowedips:
if (allowedip_nest)
mnl_attr_nest_cancel(nlh, allowedip_nest);
if (allowedips_nest)
mnl_attr_nest_end(nlh, allowedips_nest);
mnl_attr_nest_end(nlh, peer_nest);
mnl_attr_nest_end(nlh, peers_nest);
goto send;
toobig_peers:
if (peer_nest)
mnl_attr_nest_cancel(nlh, peer_nest);
mnl_attr_nest_end(nlh, peers_nest);
goto send;
send:
if (mnlg_socket_send(nlg, nlh) < 0) {
ret = -errno;
goto out;
}
errno = 0;
if (mnlg_socket_recv_run(nlg, NULL, NULL) < 0) {
ret = errno ? -errno : -EINVAL;
goto out;
}
if (peer)
goto again;
out:
mnlg_socket_close(nlg);
errno = -ret;
return ret;
}
static int parse_allowedip(const struct nlattr *attr, void *data)
{
struct wgallowedip *allowedip = data;
switch (mnl_attr_get_type(attr)) {
case WGALLOWEDIP_A_UNSPEC:
break;
case WGALLOWEDIP_A_FAMILY:
if (!mnl_attr_validate(attr, MNL_TYPE_U16))
allowedip->family = mnl_attr_get_u16(attr);
break;
case WGALLOWEDIP_A_IPADDR:
if (mnl_attr_get_payload_len(attr) == sizeof(allowedip->ip4))
memcpy(&allowedip->ip4, mnl_attr_get_payload(attr), sizeof(allowedip->ip4));
else if (mnl_attr_get_payload_len(attr) == sizeof(allowedip->ip6))
memcpy(&allowedip->ip6, mnl_attr_get_payload(attr), sizeof(allowedip->ip6));
break;
case WGALLOWEDIP_A_CIDR_MASK:
if (!mnl_attr_validate(attr, MNL_TYPE_U8))
allowedip->cidr = mnl_attr_get_u8(attr);
break;
}
return MNL_CB_OK;
}
static int parse_allowedips(const struct nlattr *attr, void *data)
{
struct wgpeer *peer = data;
struct wgallowedip *new_allowedip = calloc(1, sizeof(*new_allowedip));
int ret;
if (!new_allowedip) {
perror("calloc");
return MNL_CB_ERROR;
}
if (!peer->first_allowedip)
peer->first_allowedip = peer->last_allowedip = new_allowedip;
else {
peer->last_allowedip->next_allowedip = new_allowedip;
peer->last_allowedip = new_allowedip;
}
ret = mnl_attr_parse_nested(attr, parse_allowedip, new_allowedip);
if (!ret)
return ret;
if (!((new_allowedip->family == AF_INET && new_allowedip->cidr <= 32) || (new_allowedip->family == AF_INET6 && new_allowedip->cidr <= 128)))
return MNL_CB_ERROR;
return MNL_CB_OK;
}
static int parse_peer(const struct nlattr *attr, void *data)
{
struct wgpeer *peer = data;
switch (mnl_attr_get_type(attr)) {
case WGPEER_A_UNSPEC:
break;
case WGPEER_A_PUBLIC_KEY:
if (mnl_attr_get_payload_len(attr) == sizeof(peer->public_key)) {
memcpy(peer->public_key, mnl_attr_get_payload(attr), sizeof(peer->public_key));
peer->flags |= WGPEER_HAS_PUBLIC_KEY;
}
break;
case WGPEER_A_PRESHARED_KEY:
if (mnl_attr_get_payload_len(attr) == sizeof(peer->preshared_key)) {
memcpy(peer->preshared_key, mnl_attr_get_payload(attr), sizeof(peer->preshared_key));
if (!key_is_zero(peer->preshared_key))
peer->flags |= WGPEER_HAS_PRESHARED_KEY;
}
break;
case WGPEER_A_ENDPOINT: {
struct sockaddr *addr;
if (mnl_attr_get_payload_len(attr) < sizeof(*addr))
break;
addr = mnl_attr_get_payload(attr);
if (addr->sa_family == AF_INET && mnl_attr_get_payload_len(attr) == sizeof(peer->endpoint.addr4))
memcpy(&peer->endpoint.addr4, addr, sizeof(peer->endpoint.addr4));
else if (addr->sa_family == AF_INET6 && mnl_attr_get_payload_len(attr) == sizeof(peer->endpoint.addr6))
memcpy(&peer->endpoint.addr6, addr, sizeof(peer->endpoint.addr6));
break;
}
case WGPEER_A_PERSISTENT_KEEPALIVE_INTERVAL:
if (!mnl_attr_validate(attr, MNL_TYPE_U16))
peer->persistent_keepalive_interval = mnl_attr_get_u16(attr);
break;
case WGPEER_A_LAST_HANDSHAKE_TIME:
if (mnl_attr_get_payload_len(attr) == sizeof(peer->last_handshake_time))
memcpy(&peer->last_handshake_time, mnl_attr_get_payload(attr), sizeof(peer->last_handshake_time));
break;
case WGPEER_A_RX_BYTES:
if (!mnl_attr_validate(attr, MNL_TYPE_U64))
peer->rx_bytes = mnl_attr_get_u64(attr);
break;
case WGPEER_A_TX_BYTES:
if (!mnl_attr_validate(attr, MNL_TYPE_U64))
peer->tx_bytes = mnl_attr_get_u64(attr);
break;
case WGPEER_A_ALLOWEDIPS:
return mnl_attr_parse_nested(attr, parse_allowedips, peer);
}
return MNL_CB_OK;
}
static int parse_peers(const struct nlattr *attr, void *data)
{
struct wgdevice *device = data;
struct wgpeer *new_peer = calloc(1, sizeof(*new_peer));
int ret;
if (!new_peer) {
perror("calloc");
return MNL_CB_ERROR;
}
if (!device->first_peer)
device->first_peer = device->last_peer = new_peer;
else {
device->last_peer->next_peer = new_peer;
device->last_peer = new_peer;
}
ret = mnl_attr_parse_nested(attr, parse_peer, new_peer);
if (!ret)
return ret;
if (!(new_peer->flags & WGPEER_HAS_PUBLIC_KEY))
return MNL_CB_ERROR;
return MNL_CB_OK;
}
static int parse_device(const struct nlattr *attr, void *data)
{
struct wgdevice *device = data;
switch (mnl_attr_get_type(attr)) {
case WGDEVICE_A_UNSPEC:
break;
case WGDEVICE_A_IFINDEX:
if (!mnl_attr_validate(attr, MNL_TYPE_U32))
device->ifindex = mnl_attr_get_u32(attr);
break;
case WGDEVICE_A_IFNAME:
if (!mnl_attr_validate(attr, MNL_TYPE_STRING)) {
strncpy(device->name, mnl_attr_get_str(attr), sizeof(device->name) - 1);
device->name[sizeof(device->name) - 1] = '\0';
}
break;
case WGDEVICE_A_PRIVATE_KEY:
if (mnl_attr_get_payload_len(attr) == sizeof(device->private_key)) {
memcpy(device->private_key, mnl_attr_get_payload(attr), sizeof(device->private_key));
device->flags |= WGDEVICE_HAS_PRIVATE_KEY;
}
break;
case WGDEVICE_A_PUBLIC_KEY:
if (mnl_attr_get_payload_len(attr) == sizeof(device->public_key)) {
memcpy(device->public_key, mnl_attr_get_payload(attr), sizeof(device->public_key));
device->flags |= WGDEVICE_HAS_PUBLIC_KEY;
}
break;
case WGDEVICE_A_LISTEN_PORT:
if (!mnl_attr_validate(attr, MNL_TYPE_U16))
device->listen_port = mnl_attr_get_u16(attr);
break;
case WGDEVICE_A_FWMARK:
if (!mnl_attr_validate(attr, MNL_TYPE_U32))
device->fwmark = mnl_attr_get_u32(attr);
break;
case WGDEVICE_A_PEERS:
return mnl_attr_parse_nested(attr, parse_peers, device);
}
return MNL_CB_OK;
}
static int read_device_cb(const struct nlmsghdr *nlh, void *data)
{
return mnl_attr_parse(nlh, sizeof(struct genlmsghdr), parse_device, data);
}
static void coalesce_peers(struct wgdevice *device)
{
struct wgpeer *old_next_peer, *peer = device->first_peer;
while (peer && peer->next_peer) {
if (memcmp(peer->public_key, peer->next_peer->public_key, sizeof(peer->public_key))) {
peer = peer->next_peer;
continue;
}
if (!peer->first_allowedip) {
peer->first_allowedip = peer->next_peer->first_allowedip;
peer->last_allowedip = peer->next_peer->last_allowedip;
} else {
peer->last_allowedip->next_allowedip = peer->next_peer->first_allowedip;
peer->last_allowedip = peer->next_peer->last_allowedip;
}
old_next_peer = peer->next_peer;
peer->next_peer = old_next_peer->next_peer;
free(old_next_peer);
}
}
static int kernel_get_device(struct wgdevice **device, const char *iface)
{
int ret;
struct nlmsghdr *nlh;
struct mnlg_socket *nlg;
try_again:
ret = 0;
*device = calloc(1, sizeof(**device));
if (!*device)
return -errno;
nlg = mnlg_socket_open(WG_GENL_NAME, WG_GENL_VERSION);
if (!nlg) {
free_wgdevice(*device);
*device = NULL;
return -errno;
}
nlh = mnlg_msg_prepare(nlg, WG_CMD_GET_DEVICE, NLM_F_REQUEST | NLM_F_ACK | NLM_F_DUMP);
mnl_attr_put_strz(nlh, WGDEVICE_A_IFNAME, iface);
if (mnlg_socket_send(nlg, nlh) < 0) {
ret = -errno;
goto out;
}
errno = 0;
if (mnlg_socket_recv_run(nlg, read_device_cb, *device) < 0) {
ret = errno ? -errno : -EINVAL;
goto out;
}
coalesce_peers(*device);
out:
if (nlg)
mnlg_socket_close(nlg);
if (ret) {
free_wgdevice(*device);
if (ret == -EINTR)
goto try_again;
*device = NULL;
}
errno = -ret;
return ret;
}