+/**
+ * Copyright (C) 2017 Hans Dedecker <dedeckeh@gmail.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License v2 as published by
+ * the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ */
+
+#include <errno.h>
+#include <string.h>
+#include <syslog.h>
+
+#include <linux/netlink.h>
+#include <linux/if_addr.h>
+#include <linux/neighbour.h>
+#include <linux/rtnetlink.h>
+
+#include <netlink/msg.h>
+#include <netlink/socket.h>
+#include <netlink/attr.h>
+
+#include "odhcpd.h"
+
+static struct nl_sock *rtnl_socket = NULL;
+
+
+int netlink_init(void)
+{
+ if (!(rtnl_socket = netlink_create_socket(NETLINK_ROUTE))) {
+ syslog(LOG_ERR, "Unable to open nl socket: %s", strerror(errno));
+ return -1;
+ }
+
+ return 0;
+}
+
+
+struct nl_sock *netlink_create_socket(int protocol)
+{
+ struct nl_sock *nl_sock;
+
+ nl_sock = nl_socket_alloc();
+ if (!nl_sock)
+ goto err;
+
+ if (nl_connect(nl_sock, protocol) < 0)
+ goto err;
+
+ return nl_sock;
+
+err:
+ if (nl_sock)
+ nl_socket_free(nl_sock);
+
+ return NULL;
+}
+
+
+struct addr_info {
+ int ifindex;
+ int af;
+ struct odhcpd_ipaddr **addrs;
+ int pending;
+ ssize_t ret;
+};
+
+
+static int cb_valid_handler(struct nl_msg *msg, void *arg)
+{
+ struct addr_info *ctxt = (struct addr_info *)arg;
+ struct odhcpd_ipaddr *addrs = *(ctxt->addrs);
+ struct nlmsghdr *hdr = nlmsg_hdr(msg);
+ struct ifaddrmsg *ifa;
+ struct nlattr *nla[__IFA_MAX], *nla_addr = NULL;
+
+ if (hdr->nlmsg_type != RTM_NEWADDR)
+ return NL_SKIP;
+
+ ifa = NLMSG_DATA(hdr);
+ if (ifa->ifa_scope != RT_SCOPE_UNIVERSE ||
+ (ctxt->af != ifa->ifa_family) ||
+ (ctxt->ifindex && ifa->ifa_index != (unsigned)ctxt->ifindex))
+ return NL_SKIP;
+
+ nlmsg_parse(hdr, sizeof(*ifa), nla, __IFA_MAX - 1, NULL);
+
+ switch (ifa->ifa_family) {
+ case AF_INET6:
+ if (nla[IFA_ADDRESS])
+ nla_addr = nla[IFA_ADDRESS];
+ break;
+
+ case AF_INET:
+ if (nla[IFA_LOCAL])
+ nla_addr = nla[IFA_LOCAL];
+ break;
+
+ default:
+ break;
+ }
+ if (!nla_addr)
+ return NL_SKIP;
+
+ addrs = realloc(addrs, sizeof(*addrs)*(ctxt->ret + 1));
+ if (!addrs)
+ return NL_SKIP;
+
+ memset(&addrs[ctxt->ret], 0, sizeof(addrs[ctxt->ret]));
+ addrs[ctxt->ret].prefix = ifa->ifa_prefixlen;
+
+ nla_memcpy(&addrs[ctxt->ret].addr, nla_addr,
+ sizeof(addrs[ctxt->ret].addr));
+
+ if (nla[IFA_BROADCAST])
+ nla_memcpy(&addrs[ctxt->ret].broadcast, nla[IFA_BROADCAST],
+ sizeof(addrs[ctxt->ret].broadcast));
+
+ if (nla[IFA_CACHEINFO]) {
+ struct ifa_cacheinfo *ifc = nla_data(nla[IFA_CACHEINFO]);
+
+ addrs[ctxt->ret].preferred = ifc->ifa_prefered;
+ addrs[ctxt->ret].valid = ifc->ifa_valid;
+ }
+
+ if (ifa->ifa_flags & IFA_F_DEPRECATED)
+ addrs[ctxt->ret].preferred = 0;
+
+ ctxt->ret++;
+ *(ctxt->addrs) = addrs;
+
+ return NL_OK;
+}
+
+
+static int cb_finish_handler(_unused struct nl_msg *msg, void *arg)
+{
+ struct addr_info *ctxt = (struct addr_info *)arg;
+
+ ctxt->pending = 0;
+
+ return NL_STOP;
+}
+
+
+static int cb_error_handler(_unused struct sockaddr_nl *nla, struct nlmsgerr *err,
+ void *arg)
+{
+ struct addr_info *ctxt = (struct addr_info *)arg;
+
+ ctxt->pending = 0;
+ ctxt->ret = err->error;
+
+ return NL_STOP;
+}
+
+
+static int prefix_cmp(const void *va, const void *vb)
+{
+ const struct odhcpd_ipaddr *a = va, *b = vb;
+ int ret = 0;
+
+ if (a->prefix == b->prefix) {
+ ret = (ntohl(a->addr.in.s_addr) < ntohl(b->addr.in.s_addr)) ? 1 :
+ (ntohl(a->addr.in.s_addr) > ntohl(b->addr.in.s_addr)) ? -1 : 0;
+ } else
+ ret = a->prefix < b->prefix ? 1 : -1;
+
+ return ret;
+}
+
+
+// compare IPv6 prefixes
+static int prefix6_cmp(const void *va, const void *vb)
+{
+ const struct odhcpd_ipaddr *a = va, *b = vb;
+ uint32_t a_pref = IN6_IS_ADDR_ULA(&a->addr.in6) ? 1 : a->preferred;
+ uint32_t b_pref = IN6_IS_ADDR_ULA(&b->addr.in6) ? 1 : b->preferred;
+ return (a_pref < b_pref) ? 1 : (a_pref > b_pref) ? -1 : 0;
+}
+
+
+// Detect an IPV6-address currently assigned to the given interface
+ssize_t netlink_get_interface_addrs(int ifindex, bool v6, struct odhcpd_ipaddr **addrs)
+{
+ struct nl_msg *msg;
+ struct ifaddrmsg ifa = {
+ .ifa_family = v6? AF_INET6: AF_INET,
+ .ifa_prefixlen = 0,
+ .ifa_flags = 0,
+ .ifa_scope = 0,
+ .ifa_index = ifindex, };
+ struct nl_cb *cb = nl_cb_alloc(NL_CB_DEFAULT);
+ struct addr_info ctxt = {
+ .ifindex = ifindex,
+ .af = v6? AF_INET6: AF_INET,
+ .addrs = addrs,
+ .ret = 0,
+ .pending = 1,
+ };
+
+ if (!cb) {
+ ctxt.ret = -1;
+ goto out;
+ }
+
+ msg = nlmsg_alloc_simple(RTM_GETADDR, NLM_F_REQUEST | NLM_F_DUMP);
+
+ if (!msg) {
+ ctxt.ret = - 1;
+ goto out;
+ }
+
+ nlmsg_append(msg, &ifa, sizeof(ifa), 0);
+
+ nl_cb_set(cb, NL_CB_VALID, NL_CB_CUSTOM, cb_valid_handler, &ctxt);
+ nl_cb_set(cb, NL_CB_FINISH, NL_CB_CUSTOM, cb_finish_handler, &ctxt);
+ nl_cb_err(cb, NL_CB_CUSTOM, cb_error_handler, &ctxt);
+
+ nl_send_auto_complete(rtnl_socket, msg);
+ while (ctxt.pending > 0)
+ nl_recvmsgs(rtnl_socket, cb);
+
+ nlmsg_free(msg);
+
+ if (ctxt.ret <= 0)
+ goto out;
+
+ time_t now = odhcpd_time();
+ struct odhcpd_ipaddr *addr = *addrs;
+
+ qsort(addr, ctxt.ret, sizeof(*addr), v6 ? prefix6_cmp : prefix_cmp);
+
+ for (ssize_t i = 0; i < ctxt.ret; ++i) {
+ if (addr[i].preferred < UINT32_MAX - now)
+ addr[i].preferred += now;
+
+ if (addr[i].valid < UINT32_MAX - now)
+ addr[i].valid += now;
+ }
+
+out:
+ nl_cb_put(cb);
+
+ return ctxt.ret;
+}
+
+
+int netlink_setup_route(const struct in6_addr *addr, const int prefixlen,
+ const struct interface *iface, const struct in6_addr *gw,
+ const uint32_t metric, const bool add)
+{
+ struct nl_msg *msg;
+ struct rtmsg rtm = {
+ .rtm_family = AF_INET6,
+ .rtm_dst_len = prefixlen,
+ .rtm_src_len = 0,
+ .rtm_table = RT_TABLE_MAIN,
+ .rtm_protocol = (add ? RTPROT_STATIC : RTPROT_UNSPEC),
+ .rtm_scope = (add ? (gw ? RT_SCOPE_UNIVERSE : RT_SCOPE_LINK) : RT_SCOPE_NOWHERE),
+ .rtm_type = (add ? RTN_UNICAST : RTN_UNSPEC),
+ };
+ int ret = 0;
+
+ msg = nlmsg_alloc_simple(add ? RTM_NEWROUTE : RTM_DELROUTE,
+ add ? NLM_F_CREATE | NLM_F_REPLACE : 0);
+ if (!msg)
+ return -1;
+
+ nlmsg_append(msg, &rtm, sizeof(rtm), 0);
+
+ nla_put(msg, RTA_DST, sizeof(*addr), addr);
+ nla_put_u32(msg, RTA_OIF, iface->ifindex);
+ nla_put_u32(msg, RTA_PRIORITY, metric);
+
+ if (gw)
+ nla_put(msg, RTA_GATEWAY, sizeof(*gw), gw);
+
+ ret = nl_send_auto_complete(rtnl_socket, msg);
+ nlmsg_free(msg);
+
+ if (ret < 0)
+ return ret;
+
+ return nl_wait_for_ack(rtnl_socket);
+}
+
+
+int netlink_setup_proxy_neigh(const struct in6_addr *addr,
+ const struct interface *iface, const bool add)
+{
+ struct nl_msg *msg;
+ struct ndmsg ndm = {
+ .ndm_family = AF_INET6,
+ .ndm_flags = NTF_PROXY,
+ .ndm_ifindex = iface->ifindex,
+ };
+ int ret = 0, flags = NLM_F_REQUEST;
+
+ if (add)
+ flags |= NLM_F_REPLACE | NLM_F_CREATE;
+
+ msg = nlmsg_alloc_simple(add ? RTM_NEWNEIGH : RTM_DELNEIGH, flags);
+ if (!msg)
+ return -1;
+
+ nlmsg_append(msg, &ndm, sizeof(ndm), 0);
+
+ nla_put(msg, NDA_DST, sizeof(*addr), addr);
+
+ ret = nl_send_auto_complete(rtnl_socket, msg);
+ nlmsg_free(msg);
+
+ if (ret < 0)
+ return ret;
+
+ return nl_wait_for_ack(rtnl_socket);
+}
+
+
+int netlink_setup_addr(struct odhcpd_ipaddr *addr,
+ const struct interface *iface, const bool v6,
+ const bool add)
+{
+ struct nl_msg *msg;
+ struct ifaddrmsg ifa = {
+ .ifa_family = v6 ? AF_INET6 : AF_INET,
+ .ifa_prefixlen = addr->prefix,
+ .ifa_flags = 0,
+ .ifa_scope = 0,
+ .ifa_index = iface->ifindex, };
+ int ret = 0, flags = NLM_F_REQUEST;
+
+ if (add)
+ flags |= NLM_F_REPLACE | NLM_F_CREATE;
+
+ msg = nlmsg_alloc_simple(add ? RTM_NEWADDR : RTM_DELADDR, 0);
+ if (!msg)
+ return -1;
+
+ nlmsg_append(msg, &ifa, sizeof(ifa), flags);
+ nla_put(msg, IFA_LOCAL, v6 ? 16 : 4, &addr->addr);
+ if (v6) {
+ struct ifa_cacheinfo cinfo = { .ifa_prefered = 0xffffffffU,
+ .ifa_valid = 0xffffffffU,
+ .cstamp = 0,
+ .tstamp = 0 };
+ time_t now = odhcpd_time();
+
+ if (addr->preferred) {
+ int64_t preferred = addr->preferred - now;
+ if (preferred < 0)
+ preferred = 0;
+ else if (preferred > UINT32_MAX)
+ preferred = UINT32_MAX;
+
+ cinfo.ifa_prefered = preferred;
+ }
+
+ if (addr->valid) {
+ int64_t valid = addr->valid - now;
+ if (valid <= 0) {
+ nlmsg_free(msg);
+ return -1;
+ }
+ else if (valid > UINT32_MAX)
+ valid = UINT32_MAX;
+
+ cinfo.ifa_valid = valid;
+ }
+
+ nla_put(msg, IFA_CACHEINFO, sizeof(cinfo), &cinfo);
+
+ nla_put_u32(msg, IFA_FLAGS, IFA_F_NOPREFIXROUTE);
+ } else {
+ if (addr->broadcast.s_addr)
+ nla_put_u32(msg, IFA_BROADCAST, addr->broadcast.s_addr);
+ }
+
+ ret = nl_send_auto_complete(rtnl_socket, msg);
+ nlmsg_free(msg);
+
+ if (ret < 0)
+ return ret;
+
+ return nl_wait_for_ack(rtnl_socket);
+}
projects / project / odhcpd.git / commitdiff