diff options
Diffstat (limited to 'ipm.c')
| -rw-r--r-- | ipm.c | 216 |
1 files changed, 216 insertions, 0 deletions
@@ -0,0 +1,216 @@ +/* SPDX-License-Identifier: MIT + * + * Copyright (C) 2019 WireGuard LLC. All Rights Reserved. + */ + +#include <arpa/inet.h> +#include <libmnl/libmnl.h> +#include <linux/rtnetlink.h> +#include <stdint.h> +#include <time.h> + +#include "dbg.h" +#include "common.h" + +struct mnl_cb_data { + uint32_t ifindex; + struct wg_combined_ip *ip; + bool ip_found; + bool duplicate; +}; + +static struct mnl_socket *nl = NULL; + +static int iface_update(uint16_t cmd, uint16_t flags, uint32_t ifindex, + const uint8_t *addr, uint8_t cidr, sa_family_t family) +{ + char buf[MNL_SOCKET_BUFFER_SIZE]; + struct nlmsghdr *nlh; + unsigned int seq, portid; + struct ifaddrmsg *ifaddr; + int ret; + + portid = mnl_socket_get_portid(nl); + nlh = mnl_nlmsg_put_header(buf); + nlh->nlmsg_type = cmd; + nlh->nlmsg_flags = NLM_F_REQUEST | NLM_F_ACK | flags; + nlh->nlmsg_seq = seq = time(NULL); + ifaddr = mnl_nlmsg_put_extra_header(nlh, sizeof(struct ifaddrmsg)); + ifaddr->ifa_family = family; + ifaddr->ifa_prefixlen = cidr; + ifaddr->ifa_scope = RT_SCOPE_UNIVERSE; + ifaddr->ifa_index = ifindex; + mnl_attr_put(nlh, IFA_LOCAL, family == AF_INET ? 4 : 16, addr); + + if (mnl_socket_sendto(nl, nlh, nlh->nlmsg_len) < 0) + return -1; + + do { + ret = mnl_socket_recvfrom(nl, buf, sizeof(buf)); + if (ret <= MNL_CB_STOP) + break; + ret = mnl_cb_run(buf, ret, seq, portid, NULL, NULL); + } while (ret > 0); + + if (ret == -1) + return -1; + + return 0; +} + +static int data_attr_cb(const struct nlattr *attr, void *data) +{ + const struct nlattr **tb = data; + int type = mnl_attr_get_type(attr); + + /* skip unsupported attribute in user-space */ + if (mnl_attr_type_valid(attr, IFA_MAX) < 0) + return MNL_CB_OK; + + switch (type) { + case IFA_ADDRESS: + if (mnl_attr_validate(attr, MNL_TYPE_BINARY) < 0) { + perror("mnl_attr_validate"); + return MNL_CB_ERROR; + } + break; + } + tb[type] = attr; + return MNL_CB_OK; +} + +static int data_cb(const struct nlmsghdr *nlh, void *data) +{ + struct nlattr *tb[IFA_MAX + 1] = {}; + struct ifaddrmsg *ifa = mnl_nlmsg_get_payload(nlh); + struct mnl_cb_data *cb_data = (struct mnl_cb_data *)data; + + if (ifa->ifa_index != cb_data->ifindex) + return MNL_CB_OK; + + if (ifa->ifa_scope != RT_SCOPE_LINK) + return MNL_CB_OK; + + mnl_attr_parse(nlh, sizeof(*ifa), data_attr_cb, tb); + + if (!tb[IFA_ADDRESS]) + return MNL_CB_OK; + + if (cb_data->ip_found) { + cb_data->duplicate = true; + return MNL_CB_OK; + } + + memcpy(cb_data->ip, mnl_attr_get_payload(tb[IFA_ADDRESS]), + ifa->ifa_family == AF_INET ? 4 : 16); + cb_data->ip->cidr = ifa->ifa_prefixlen; + cb_data->ip->family = ifa->ifa_family; + + char out[INET6_ADDRSTRLEN]; + inet_ntop(ifa->ifa_family, cb_data->ip, out, sizeof(out)); + debug("index=%d, family=%d, addr=%s\n", ifa->ifa_index, ifa->ifa_family, + out); + + cb_data->ip_found = true; + + return MNL_CB_OK; +} + +static int iface_get_all_addrs(uint8_t family, void *cb_data) +{ + char buf[MNL_SOCKET_BUFFER_SIZE]; + struct nlmsghdr *nlh; + /* TODO: rtln-addr-dump from libmnl uses rtgenmsg here? */ + struct ifaddrmsg *ifaddr; + int ret; + unsigned int seq, portid; + + /* You'd think that we could just request addresses from a specific + * interface, via NLM_F_MATCH or something, but we can't. See also: + * https://marc.info/?l=linux-netdev&m=132508164508217 + */ + seq = time(NULL); + portid = mnl_socket_get_portid(nl); + nlh = mnl_nlmsg_put_header(buf); + nlh->nlmsg_type = RTM_GETADDR; + nlh->nlmsg_flags = NLM_F_REQUEST | NLM_F_DUMP; + nlh->nlmsg_seq = seq; + ifaddr = mnl_nlmsg_put_extra_header(nlh, sizeof(struct ifaddrmsg)); + ifaddr->ifa_family = family; + + if (mnl_socket_sendto(nl, nlh, nlh->nlmsg_len) < 0) + return -1; + + do { + ret = mnl_socket_recvfrom(nl, buf, sizeof(buf)); + if (ret <= MNL_CB_STOP) + break; + ret = mnl_cb_run(buf, ret, seq, portid, data_cb, cb_data); + } while (ret > 0); + + if (ret == -1) + return -1; + + return 0; +} + +void ipm_init() +{ + nl = mnl_socket_open(NETLINK_ROUTE); + if (nl == NULL) + fatal("mnl_socket_open()"); + + if (mnl_socket_bind(nl, 0, MNL_SOCKET_AUTOPID) < 0) + fatal("mnl_socket_bind()"); +} + +void ipm_free() +{ + if (nl) + mnl_socket_close(nl); +} + +int ipm_newaddr_v4(uint32_t ifindex, const struct in_addr *ip) +{ + return iface_update(RTM_NEWADDR, NLM_F_REPLACE | NLM_F_CREATE, ifindex, + (uint8_t *)ip, 32, AF_INET); +} + +int ipm_newaddr_v6(uint32_t ifindex, const struct in6_addr *ip) +{ + return iface_update(RTM_NEWADDR, NLM_F_REPLACE | NLM_F_CREATE, ifindex, + (uint8_t *)ip, 128, AF_INET6); +} + +int ipm_deladdr_v4(uint32_t ifindex, const struct in_addr *ip) +{ + return iface_update(RTM_DELADDR, 0, ifindex, (uint8_t *)ip, 32, + AF_INET); +} + +int ipm_deladdr_v6(uint32_t ifindex, const struct in6_addr *ip) +{ + return iface_update(RTM_DELADDR, 0, ifindex, (uint8_t *)ip, 128, + AF_INET6); +} + +int ipm_getlladdr(uint32_t ifindex, struct wg_combined_ip *addr) +{ + struct mnl_cb_data cb_data = { + .ifindex = ifindex, + .ip = addr, + .ip_found = false, + .duplicate = false, + }; + + if (iface_get_all_addrs(AF_INET6, &cb_data)) + return -1; + + if (!cb_data.ip_found) + return -2; + + if (cb_data.duplicate) + return -3; + + return 0; +} |