diff options
Diffstat (limited to 'src/ipc-linux.h')
| -rw-r--r-- | src/ipc-linux.h | 519 |
1 files changed, 519 insertions, 0 deletions
diff --git a/src/ipc-linux.h b/src/ipc-linux.h new file mode 100644 index 0000000..5883ffe --- /dev/null +++ b/src/ipc-linux.h @@ -0,0 +1,519 @@ +// 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; +} |