1 files changed, 873 insertions, 0 deletions

diff --git a/src/pingu_netlink.c b/src/pingu_netlink.c
new file mode 100644
index 0000000..d149275
--- /dev/null
+++ b/src/pingu_netlink.c
@@ -0,0 +1,873 @@
+/* pingu_netlink.c - Linux netlink glue
+ *
+ * Copyright (C) 2007-2009 Timo Teräs <timo.teras@iki.fi>
+ * Copyright (C) 2011 Natanael Copa <ncopa@alpinelinux.org>
+ * All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 or later as
+ * published by the Free Software Foundation.
+ *
+ * See http://www.gnu.org/ for details.
+ */
+
+#include <arpa/inet.h>
+#include <asm/types.h>
+#include <sys/socket.h>
+#include <linux/netlink.h>
+#include <linux/rtnetlink.h>
+#include <linux/ip.h>
+#include <net/if.h>
+#include <linux/fib_rules.h>
+#include <netinet/in.h>
+
+#include <time.h>
+#include <stdio.h>
+#include <fcntl.h>
+#include <errno.h>
+#include <unistd.h>
+#include <stdlib.h>
+#include <malloc.h>
+#include <string.h>
+#include <stdint.h>
+
+#include <ev.h>
+
+#include "log.h"
+#include "pingu_iface.h"
+#include "pingu_host.h"
+#include "pingu_netlink.h"
+
+#ifndef IFF_LOWER_UP
+/* from linux/if.h which conflicts with net/if.h */
+#define IFF_LOWER_UP	0x10000		/* driver signals L1 up	*/
+#endif
+
+#ifndef ARRAY_SIZE
+#define ARRAY_SIZE(array) (sizeof(array) / sizeof((array)[0]))
+#endif
+
+#ifndef TRUE
+#define TRUE 1
+#endif
+#ifndef FALSE
+#define FALSE 0
+#endif
+
+#define NETLINK_KERNEL_BUFFER	(256 * 1024)
+#define NETLINK_RECV_BUFFER	(8 * 1024)
+
+#define NLMSG_TAIL(nmsg) \
+	((struct rtattr *) (((void *) (nmsg)) + NLMSG_ALIGN((nmsg)->nlmsg_len)))
+
+#define NDA_RTA(r)  ((struct rtattr*)(((char*)(r)) + NLMSG_ALIGN(sizeof(struct ndmsg))))
+#define NDA_PAYLOAD(n) NLMSG_PAYLOAD(n,sizeof(struct ndmsg))
+
+typedef void (*netlink_dispatch_f)(struct nlmsghdr *msg);
+
+struct netlink_fd {
+	int fd;
+	__u32 seq;
+	struct ev_io io;
+
+	int dispatch_size;
+	const netlink_dispatch_f *dispatch;
+};
+
+static const int netlink_groups[] = {
+	0,
+	RTMGRP_LINK,
+	RTMGRP_IPV4_IFADDR,
+	RTMGRP_IPV4_ROUTE,
+};
+static struct netlink_fd netlink_fds[ARRAY_SIZE(netlink_groups)];
+#define talk_fd netlink_fds[0]
+
+static void netlink_parse_rtattr(struct rtattr *tb[], int max, struct rtattr *rta, int len)
+{
+	memset(tb, 0, sizeof(struct rtattr *) * (max + 1));
+	while (RTA_OK(rta, len)) {
+		if (rta->rta_type <= max)
+			tb[rta->rta_type] = rta;
+		rta = RTA_NEXT(rta,len);
+	}
+}
+
+static int netlink_add_rtattr_l(struct nlmsghdr *n, int maxlen, int type,
+				const void *data, int alen)
+{
+	int len = RTA_LENGTH(alen);
+	struct rtattr *rta;
+
+	if (NLMSG_ALIGN(n->nlmsg_len) + RTA_ALIGN(len) > maxlen)
+		return FALSE;
+
+	rta = NLMSG_TAIL(n);
+	rta->rta_type = type;
+	rta->rta_len = len;
+	memcpy(RTA_DATA(rta), data, alen);
+	n->nlmsg_len = NLMSG_ALIGN(n->nlmsg_len) + RTA_ALIGN(len);
+	return TRUE;
+}
+
+static int netlink_add_rtattr_addr_any(struct nlmsghdr *n, int maxlen,
+					int type, union sockaddr_any *sa)
+{
+	switch (sa->sa.sa_family) {
+	case AF_INET:
+		return netlink_add_rtattr_l(n, maxlen, type, &sa->sin.sin_addr, 4);
+		break;
+	case AF_INET6:
+		return netlink_add_rtattr_l(n, maxlen, type, &sa->sin6.sin6_addr, 16);
+		break;
+	}
+	return FALSE;
+}
+
+static int netlink_add_subrtattr_l(struct rtattr *rta, int maxlen, int type,
+				   const void *data, int alen)
+{
+        struct rtattr *subrta;
+        int len = RTA_LENGTH(alen);
+
+        if (RTA_ALIGN(rta->rta_len) + RTA_ALIGN(len) > maxlen)
+		return FALSE;
+
+        subrta = (struct rtattr*)(((char*)rta) + RTA_ALIGN(rta->rta_len));
+        subrta->rta_type = type;
+        subrta->rta_len = len;
+        memcpy(RTA_DATA(subrta), data, alen);
+        rta->rta_len = NLMSG_ALIGN(rta->rta_len) + RTA_ALIGN(len);
+        return alen;
+}
+
+static int netlink_add_subrtattr_addr_any(struct rtattr *rta, int maxlen,
+					int type, union sockaddr_any *sa)
+{
+	switch (sa->sa.sa_family) {
+	case AF_INET:
+		return netlink_add_subrtattr_l(rta, maxlen, type, &sa->sin.sin_addr, 4);
+		break;
+	case AF_INET6:
+		return netlink_add_subrtattr_l(rta, maxlen, type, &sa->sin6.sin6_addr, 16);
+		break;
+	}
+	return FALSE;
+}
+
+static int netlink_get_error(struct nlmsghdr *hdr)
+{
+	struct nlmsgerr *nlerr = (struct nlmsgerr*)NLMSG_DATA(hdr);
+	if (hdr->nlmsg_type != NLMSG_ERROR)
+		return 0;
+	if (hdr->nlmsg_len < NLMSG_LENGTH(sizeof(struct nlmsgerr))) {
+		log_error("Netlink error message truncated");
+		return -1;
+	}
+	return -nlerr->error;
+}
+
+static int netlink_log_error(struct nlmsghdr *hdr)
+{
+	int err = netlink_get_error(hdr);
+	if (err > 0)
+		log_error("Netlink error: %s", strerror(err));
+	return err;
+}
+
+static int netlink_receive(struct netlink_fd *fd, struct nlmsghdr *reply)
+{
+	struct sockaddr_nl nladdr;
+	struct iovec iov;
+	struct msghdr msg = {
+		.msg_name = &nladdr,
+		.msg_namelen = sizeof(nladdr),
+		.msg_iov = &iov,
+		.msg_iovlen = 1,
+	};
+	int got_reply = FALSE, len;
+	char buf[NETLINK_RECV_BUFFER];
+
+	iov.iov_base = buf;
+	while (!got_reply) {
+		int status;
+		struct nlmsghdr *h;
+
+		iov.iov_len = sizeof(buf);
+		status = recvmsg(fd->fd, &msg, MSG_DONTWAIT);
+		if (status < 0) {
+			if (errno == EINTR)
+				continue;
+			if (errno == EAGAIN)
+				return reply == NULL;
+			log_perror("Netlink overrun");
+			continue;
+		}
+
+		if (status == 0) {
+			log_error("Netlink returned EOF");
+			return FALSE;
+		}
+
+		h = (struct nlmsghdr *) buf;
+		while (NLMSG_OK(h, status)) {
+			if (reply != NULL &&
+			    h->nlmsg_seq == reply->nlmsg_seq) {
+				len = h->nlmsg_len;
+				if (len > reply->nlmsg_len) {
+					log_error("Netlink message truncated");
+					len = reply->nlmsg_len;
+				}
+				memcpy(reply, h, len);
+				got_reply = TRUE;
+			} else if (h->nlmsg_type <= fd->dispatch_size &&
+				fd->dispatch[h->nlmsg_type] != NULL) {
+				fd->dispatch[h->nlmsg_type](h);
+			} else if (h->nlmsg_type == NLMSG_ERROR) {
+				return netlink_log_error(h);
+			} else if (h->nlmsg_type != NLMSG_DONE) {
+				log_info("Unknown NLmsg: 0x%08x, len %d",
+					  h->nlmsg_type, h->nlmsg_len);
+			}
+			h = NLMSG_NEXT(h, status);
+		}
+	}
+
+	return TRUE;
+}
+
+static int netlink_send(struct netlink_fd *fd, struct nlmsghdr *req)
+{
+        struct sockaddr_nl nladdr;
+        struct iovec iov = {
+                .iov_base = (void*) req,
+                .iov_len = req->nlmsg_len
+        };
+        struct msghdr msg = {
+                .msg_name = &nladdr,
+                .msg_namelen = sizeof(nladdr),
+                .msg_iov = &iov,
+                .msg_iovlen = 1,
+        };
+        int status;
+
+        memset(&nladdr, 0, sizeof(nladdr));
+        nladdr.nl_family = AF_NETLINK;
+
+        req->nlmsg_seq = ++fd->seq;
+
+        status = sendmsg(fd->fd, &msg, 0);
+        if (status < 0) {
+                log_perror("Cannot talk to rtnetlink");
+                return FALSE;
+        }
+        return TRUE;
+}
+
+static int netlink_talk(struct netlink_fd *fd, struct nlmsghdr *req,
+		 size_t replysize, struct nlmsghdr *reply)
+{
+	if (reply == NULL)
+		req->nlmsg_flags |= NLM_F_ACK;
+
+	if (!netlink_send(fd, req))
+		return FALSE;
+
+	if (reply == NULL)
+		return TRUE;
+
+	reply->nlmsg_len = replysize;
+	return netlink_receive(fd, reply);
+}
+
+static int netlink_enumerate(struct netlink_fd *fd, int family, int type)
+{
+	struct {
+		struct nlmsghdr nlh;
+		struct rtgenmsg g;
+	} req;
+	struct sockaddr_nl addr;
+
+	memset(&addr, 0, sizeof(addr));
+	addr.nl_family = AF_NETLINK;
+
+	memset(&req, 0, sizeof(req));
+	req.nlh.nlmsg_len = sizeof(req);
+	req.nlh.nlmsg_type = type;
+	req.nlh.nlmsg_flags = NLM_F_ROOT | NLM_F_MATCH | NLM_F_REQUEST;
+	req.nlh.nlmsg_pid = 0;
+	req.nlh.nlmsg_seq = ++fd->seq;
+	req.g.rtgen_family = family;
+
+	return sendto(fd->fd, (void *) &req, sizeof(req), 0,
+		      (struct sockaddr *) &addr, sizeof(addr)) >= 0;
+}
+
+int netlink_route_modify(struct netlink_fd *fd, int action_type,
+			 struct pingu_route *route,
+			 int table)
+{
+	struct {
+		struct nlmsghdr	nlh;
+		struct rtmsg	msg;
+		char buf[1024];
+	} req;
+
+	memset(&req, 0, sizeof(req));
+
+	req.nlh.nlmsg_len = NLMSG_LENGTH(sizeof(struct rtmsg));
+	req.nlh.nlmsg_flags = NLM_F_REQUEST | NLM_F_ACK;
+	req.nlh.nlmsg_type = action_type;
+	if (action_type == RTM_NEWROUTE)
+		req.nlh.nlmsg_flags |= NLM_F_CREATE | NLM_F_REPLACE;
+
+	req.msg.rtm_family = route->dest.sa.sa_family;
+	req.msg.rtm_table = table;
+	req.msg.rtm_dst_len = route->dst_len;
+	req.msg.rtm_protocol = route->protocol;
+	req.msg.rtm_scope = route->scope;
+	req.msg.rtm_type = route->type;
+
+	netlink_add_rtattr_addr_any(&req.nlh, sizeof(req), RTA_DST,
+					&route->dest);
+	netlink_add_rtattr_addr_any(&req.nlh, sizeof(req), RTA_GATEWAY,
+					&route->gw_addr);
+	netlink_add_rtattr_l(&req.nlh, sizeof(req), RTA_OIF, &route->dev_index, 4);
+	if (route->metric != 0)
+		netlink_add_rtattr_l(&req.nlh, sizeof(req), RTA_PRIORITY,
+				     &route->metric, 4);
+
+	if (!netlink_talk(fd, &req.nlh, sizeof(req), &req.nlh))
+		return FALSE;
+	return netlink_get_error(&req.nlh);
+}
+
+static int add_one_nh(struct rtattr *rta, struct rtnexthop *rtnh,
+		      struct pingu_iface *iface,
+		      struct pingu_route *route)
+{
+	int addr_size;
+	char addrbuf[40] = "";
+	if (route == NULL)
+		return 0;
+	addr_size = netlink_add_subrtattr_addr_any(rta, 1024, RTA_GATEWAY,
+						&route->gw_addr);
+	if (addr_size > 0)
+		rtnh->rtnh_len += sizeof(struct rtattr) + addr_size;
+	log_debug("adding nexthop%s%s dev %s",
+		  route->gw_addr.sa.sa_family ? " via " : "",
+		  sockaddr_to_string(&route->gw_addr, addrbuf, sizeof(addrbuf)),
+		  iface->name);
+	if (iface->balance_weight)
+		rtnh->rtnh_hops = iface->balance_weight - 1;
+	rtnh->rtnh_ifindex = iface->index;
+	return 1;
+}
+
+static int add_nexthops(struct nlmsghdr *nlh, size_t nlh_size,
+			 struct list_head *iface_list, int action_type)
+{
+	char buf[1024];
+	struct rtattr *rta = (void *)buf;
+	struct rtnexthop *rtnh;
+	struct pingu_iface *iface;
+	struct pingu_route *route;
+	int count = 0;
+
+	memset(buf, 0, sizeof(buf));
+	rta->rta_type = RTA_MULTIPATH;
+	rta->rta_len = RTA_LENGTH(0);
+	rtnh = RTA_DATA(rta);
+
+	list_for_each_entry(iface, iface_list, iface_list_entry) {
+		route = pingu_route_first_default(&iface->route_list);
+		switch (action_type) {
+		case RTM_NEWROUTE:
+			if ((!iface->balance) || iface->index == 0
+			    || !pingu_iface_gw_is_online(iface)
+			    || route == NULL) {
+				iface->has_multipath = 0;
+				continue;
+			}
+			iface->has_multipath = 1;
+			break;
+		case RTM_DELROUTE:
+			if (!iface->has_multipath)
+				continue;
+			iface->has_multipath = 0;
+			break;
+		}
+		memset(rtnh, 0, sizeof(*rtnh));
+		rtnh->rtnh_len = sizeof(*rtnh);
+		rta->rta_len += rtnh->rtnh_len;
+		count += add_one_nh(rta, rtnh, iface, route);
+		rtnh = RTNH_NEXT(rtnh);
+	}
+	if (rta->rta_len > RTA_LENGTH(0))
+		netlink_add_rtattr_l(nlh, nlh_size, RTA_MULTIPATH,
+				     RTA_DATA(rta), RTA_PAYLOAD(rta));
+	return count;
+}
+
+int netlink_route_multipath(struct netlink_fd *fd, int action_type,
+			    struct list_head *iface_list, int table)
+{
+	struct {
+		struct nlmsghdr	nlh;
+		struct rtmsg	msg;
+		char buf[1024];
+	} req;
+	union sockaddr_any dest;
+	int count = 0;
+
+	memset(&req, 0, sizeof(req));
+	memset(&dest, 0, sizeof(dest));
+	dest.sa.sa_family = AF_INET;
+
+	req.nlh.nlmsg_len = NLMSG_LENGTH(sizeof(struct rtmsg));
+	req.nlh.nlmsg_flags = NLM_F_REQUEST | NLM_F_ACK;
+	req.nlh.nlmsg_type = action_type;
+	if (action_type == RTM_NEWROUTE)
+		req.nlh.nlmsg_flags |= NLM_F_CREATE | NLM_F_REPLACE;
+
+	req.msg.rtm_family = AF_INET;
+	req.msg.rtm_table = table;
+	req.msg.rtm_dst_len = 0;
+	req.msg.rtm_protocol = RTPROT_BOOT;
+	req.msg.rtm_scope = RT_SCOPE_UNIVERSE;
+	req.msg.rtm_type = RTN_UNICAST;
+
+	netlink_add_rtattr_addr_any(&req.nlh, sizeof(req), RTA_DST,
+					&dest);
+
+	count = add_nexthops(&req.nlh, sizeof(req), iface_list, action_type);
+	if (count == 0)
+		req.nlh.nlmsg_type = RTM_DELROUTE;
+
+	if (!netlink_talk(fd, &req.nlh, sizeof(req), &req.nlh))
+		return -1;
+	return netlink_get_error(&req.nlh);
+}
+
+int netlink_route_replace_or_add(struct netlink_fd *fd,
+				 struct pingu_route *route,
+				 int table)
+{
+	return netlink_route_modify(fd, RTM_NEWROUTE, route, table);
+}
+
+int netlink_route_delete(struct netlink_fd *fd,
+			 struct pingu_route *route,
+			 int table)
+{
+	return netlink_route_modify(fd, RTM_DELROUTE, route, table);
+}
+
+static void netlink_route_flush(struct netlink_fd *fd, struct pingu_iface *iface)
+{
+	struct pingu_route *gw;
+	int err;
+	list_for_each_entry(gw, &iface->route_list, route_list_entry) {
+		err = netlink_route_delete(fd, gw, iface->route_table);
+		if (err > 0)
+			log_error("%s: Failed to clean up route in table %i: ",
+				  iface->name, iface->route_table, strerror(err));
+	}
+}
+
+int netlink_rule_modify(struct netlink_fd *fd,
+	struct pingu_iface *iface, int rtm_type, int rule_type)
+{
+	struct {
+		struct nlmsghdr	nlh;
+		struct rtmsg	msg;
+		char buf[1024];
+	} req;
+
+	memset(&req, 0, sizeof(req));
+
+	req.nlh.nlmsg_len = NLMSG_LENGTH(sizeof(struct rtmsg));
+	req.nlh.nlmsg_flags = NLM_F_REQUEST | NLM_F_ACK;
+	req.nlh.nlmsg_type = rtm_type;
+	if (rtm_type == RTM_NEWRULE)
+		req.nlh.nlmsg_flags |= NLM_F_CREATE | NLM_F_REPLACE;
+
+	req.msg.rtm_family = AF_INET;
+	req.msg.rtm_table = iface->route_table;
+	req.msg.rtm_protocol = RTPROT_BOOT;
+	req.msg.rtm_scope = RT_SCOPE_UNIVERSE;
+	req.msg.rtm_type = RTN_UNICAST;
+
+	switch (rule_type) {
+	case FRA_SRC:
+		req.msg.rtm_src_len = 32;
+		netlink_add_rtattr_addr_any(&req.nlh, sizeof(req), FRA_SRC,
+					    &iface->primary_addr);
+		break;
+	case FRA_FWMARK:
+		netlink_add_rtattr_l(&req.nlh, sizeof(req), FRA_FWMARK,
+				     &iface->fwmark, 4);
+		break;
+	default:
+		log_error("%s: unsupported route rule. Should not happen.",
+			  iface->name);
+	}
+
+	if (iface->rule_priority != 0)
+		netlink_add_rtattr_l(&req.nlh, sizeof(req), FRA_PRIORITY,
+				     &iface->rule_priority, 4);
+
+	if (!netlink_talk(fd, &req.nlh, sizeof(req), &req.nlh))
+		return -1;
+
+	return netlink_get_error(&req.nlh);
+}
+
+int netlink_rule_del(struct netlink_fd *fd,	struct pingu_iface *iface)
+{
+	if (iface->fwmark)
+		netlink_rule_modify(fd, iface, RTM_DELRULE, FRA_FWMARK);
+	return netlink_rule_modify(fd, iface, RTM_DELRULE, FRA_SRC);
+}
+
+int netlink_rule_replace_or_add(struct netlink_fd *fd, struct pingu_iface *iface)
+{
+	netlink_rule_del(fd, iface);
+	if (iface->fwmark)
+		netlink_rule_modify(fd, iface, RTM_NEWRULE, FRA_FWMARK);
+	return netlink_rule_modify(fd, iface, RTM_NEWRULE, FRA_SRC);
+}
+
+static void netlink_link_new_cb(struct nlmsghdr *msg)
+{
+	struct pingu_iface *iface;
+	struct ifinfomsg *ifi = NLMSG_DATA(msg);
+	struct rtattr *rta[IFLA_MAX+1];
+	const char *ifname;
+
+	netlink_parse_rtattr(rta, IFLA_MAX, IFLA_RTA(ifi), IFLA_PAYLOAD(msg));
+	if (rta[IFLA_IFNAME] == NULL)
+		return;
+
+	ifname = RTA_DATA(rta[IFLA_IFNAME]);
+	iface = pingu_iface_get_by_name(ifname);
+	if (iface == NULL)
+		return;
+
+	if (iface->index == 0 && ifi->ifi_index != 0)
+		log_info("New interface: %s", ifname);
+
+	iface->index = ifi->ifi_index;
+	if (ifi->ifi_flags & IFF_LOWER_UP) {
+		log_info("%s: got link", ifname);
+		iface->has_link = 1;
+	}
+}
+
+static void netlink_link_del_cb(struct nlmsghdr *msg)
+{
+	struct pingu_iface *iface;
+	struct ifinfomsg *ifi = NLMSG_DATA(msg);
+	struct rtattr *rta[IFLA_MAX+1];
+	const char *ifname;
+
+	netlink_parse_rtattr(rta, IFLA_MAX, IFLA_RTA(ifi), IFLA_PAYLOAD(msg));
+	if (rta[IFLA_IFNAME] == NULL)
+		return;
+
+	ifname = RTA_DATA(rta[IFLA_IFNAME]);
+	iface = pingu_iface_get_by_name(ifname);
+	if (iface == NULL)
+		return;
+
+	log_info("Interface '%s' deleted", ifname);
+	iface->index = 0;
+	iface->has_link = 0;
+	pingu_host_iface_deleted(iface);
+}
+
+static void netlink_addr_new_cb(struct nlmsghdr *msg)
+{
+	struct pingu_iface *iface;
+	struct ifaddrmsg *ifa = NLMSG_DATA(msg);
+	struct rtattr *rta[IFA_MAX+1];
+	int err;
+
+	if (ifa->ifa_flags & IFA_F_SECONDARY)
+		return;
+
+	netlink_parse_rtattr(rta, IFA_MAX, IFA_RTA(ifa), IFA_PAYLOAD(msg));
+	if (rta[IFA_LOCAL] == NULL)
+		return;
+
+	iface = pingu_iface_get_by_index(ifa->ifa_index);
+	if (iface == NULL || rta[IFA_LOCAL] == NULL)
+		return;
+
+	pingu_iface_set_addr(iface, ifa->ifa_family,
+			     RTA_DATA(rta[IFA_LOCAL]),
+			     RTA_PAYLOAD(rta[IFA_LOCAL]));
+	pingu_iface_bind_socket(iface, 1);
+	err = netlink_rule_replace_or_add(&talk_fd, iface);
+	if (err == 0)
+		iface->has_route_rule = 1;
+	if (err > 0)
+		log_error("%s: Failed to add route rule: %s", iface->name,
+			  strerror(err));
+}
+
+static void netlink_addr_del_cb(struct nlmsghdr *nlmsg)
+{
+	struct pingu_iface *iface;
+	struct ifaddrmsg *ifa = NLMSG_DATA(nlmsg);
+	struct rtattr *rta[IFA_MAX+1];
+
+	if (ifa->ifa_flags & IFA_F_SECONDARY)
+		return;
+
+	netlink_parse_rtattr(rta, IFA_MAX, IFA_RTA(ifa), IFA_PAYLOAD(nlmsg));
+	if (rta[IFA_LOCAL] == NULL)
+		return;
+
+	iface = pingu_iface_get_by_index(ifa->ifa_index);
+	if (iface == NULL)
+		return;
+
+	netlink_rule_del(&talk_fd, iface);
+	pingu_iface_set_addr(iface, 0, NULL, 0);
+}
+
+static struct pingu_route *gw_from_rtmsg(struct pingu_route *gw,
+					      struct rtmsg *rtm,
+					      struct rtattr **rta)
+{
+	memset(gw, 0, sizeof(*gw));
+	gw->dst_len = rtm->rtm_dst_len;
+	gw->src_len = rtm->rtm_src_len;
+	gw->dest.sa.sa_family = rtm->rtm_family;
+	gw->protocol = rtm->rtm_protocol;
+	gw->scope = rtm->rtm_scope;
+	gw->type = rtm->rtm_type;
+	gw->dev_index = *(int*)RTA_DATA(rta[RTA_OIF]);
+
+	if (rta[RTA_SRC] != NULL)
+		sockaddr_init(&gw->src, rtm->rtm_family, RTA_DATA(rta[RTA_SRC]));
+
+	if (rta[RTA_DST] != NULL)
+		sockaddr_init(&gw->dest, rtm->rtm_family, RTA_DATA(rta[RTA_DST]));
+
+	if (rta[RTA_PRIORITY] != NULL)
+		gw->metric = *(uint32_t *)RTA_DATA(rta[RTA_PRIORITY]);
+
+	if (rta[RTA_GATEWAY] != NULL)
+		sockaddr_init(&gw->gw_addr, rtm->rtm_family, RTA_DATA(rta[RTA_GATEWAY]));
+	return gw;
+}
+
+static void log_route_change(struct pingu_route *route, int table,
+			     int action)
+{
+	char routestr[512] = "";
+	char *actionstr = "New";
+	if (action == RTM_DELROUTE)
+		actionstr = "Delete";
+
+	log_info("%s route to %s table %i", actionstr,
+		 pingu_route_to_string(route, routestr, sizeof(routestr)),
+		 table);
+}
+
+void route_changed_for_iface(struct pingu_iface *iface,
+			     struct pingu_route *route, int action)
+{
+	int err = 0;
+	log_route_change(route, iface->route_table, action);
+	/* Kernel will remove the alternate route when we lose the
+	 * address so we don't need try remove it ourselves */
+	if (action != RTM_DELROUTE || iface->has_address)
+		err = netlink_route_modify(&talk_fd, action, route,
+					   iface->route_table);
+	if (err > 0)
+		log_error("Failed to %s route to table %i",
+			  action == RTM_NEWROUTE ? "add" : "delete",
+			  iface->route_table);
+	pingu_iface_gw_action(iface, route, action);
+}
+
+static void netlink_route_cb_action(struct nlmsghdr *msg, int action)
+{
+	struct pingu_iface *iface;
+	struct rtmsg *rtm = NLMSG_DATA(msg);
+	struct rtattr *rta[RTA_MAX+1];
+
+	struct pingu_route route;
+
+	/* ignore route changes that we made ourselves via talk_fd */
+	if (msg->nlmsg_pid == getpid())
+		return;
+
+	netlink_parse_rtattr(rta, RTA_MAX, RTM_RTA(rtm), RTM_PAYLOAD(msg));
+	if (rta[RTA_OIF] == NULL || rtm->rtm_family != PF_INET
+	    || rtm->rtm_table != RT_TABLE_MAIN)
+		return;
+
+	gw_from_rtmsg(&route, rtm, rta);
+	iface = pingu_iface_get_by_index(route.dev_index);
+	if (iface == NULL)
+		return;
+
+	route_changed_for_iface(iface, &route, action);
+}
+
+static void netlink_route_new_cb(struct nlmsghdr *msg)
+{
+	netlink_route_cb_action(msg, RTM_NEWROUTE);
+}
+
+
+static void netlink_route_del_cb(struct nlmsghdr *msg)
+{
+	netlink_route_cb_action(msg, RTM_DELROUTE);
+}
+
+static const netlink_dispatch_f route_dispatch[RTM_MAX] = {
+	[RTM_NEWLINK] = netlink_link_new_cb,
+	[RTM_DELLINK] = netlink_link_del_cb,
+	[RTM_NEWADDR] = netlink_addr_new_cb,
+	[RTM_DELADDR] = netlink_addr_del_cb,
+	[RTM_NEWROUTE] = netlink_route_new_cb,
+	[RTM_DELROUTE] = netlink_route_del_cb,
+};
+
+static void netlink_read_cb(struct ev_loop *loop, struct ev_io *w, int revents)
+{
+	struct netlink_fd *nfd = container_of(w, struct netlink_fd, io);
+
+	if (revents & EV_READ)
+		netlink_receive(nfd, NULL);
+}
+
+static void netlink_close(struct ev_loop *loop, struct netlink_fd *fd)
+{
+	if (fd->fd >= 0) {
+		if (loop != NULL)
+			ev_io_stop(loop, &fd->io);
+		close(fd->fd);
+		fd->fd = 0;
+	}
+}
+
+static int netlink_open(struct ev_loop *loop, struct netlink_fd *fd,
+			int protocol, int groups)
+{
+	struct sockaddr_nl addr;
+	int buf = NETLINK_KERNEL_BUFFER;
+
+	fd->fd = socket(AF_NETLINK, SOCK_RAW, protocol);
+	fd->seq = time(NULL);
+	if (fd->fd < 0) {
+		log_perror("Cannot open netlink socket");
+		return FALSE;
+	}
+
+	fcntl(fd->fd, F_SETFD, FD_CLOEXEC);
+	if (setsockopt(fd->fd, SOL_SOCKET, SO_SNDBUF, &buf, sizeof(buf)) < 0) {
+		log_perror("SO_SNDBUF");
+		goto error;
+	}
+
+	if (setsockopt(fd->fd, SOL_SOCKET, SO_RCVBUF, &buf, sizeof(buf)) < 0) {
+		log_perror("SO_RCVBUF");
+		goto error;
+	}
+
+	memset(&addr, 0, sizeof(addr));
+	addr.nl_family = AF_NETLINK;
+	addr.nl_groups = groups;
+	if (bind(fd->fd, (struct sockaddr *) &addr, sizeof(addr)) < 0) {
+		log_perror("Cannot bind netlink socket");
+		goto error;
+	}
+
+	ev_io_init(&fd->io, netlink_read_cb, fd->fd, EV_READ);
+	ev_io_start(loop, &fd->io);
+
+	return TRUE;
+
+error:
+	netlink_close(loop, fd);
+	return FALSE;
+}
+
+
+int kernel_route_modify(int action, struct pingu_route *route,
+			int table)
+{
+	log_route_change(route, table, action);
+	return netlink_route_modify(&talk_fd, action, route, table);
+}
+
+int kernel_route_multipath(int action, struct list_head *iface_list, int table)
+{
+	return netlink_route_multipath(&talk_fd, action, iface_list, table);
+}
+
+int kernel_init(struct ev_loop *loop)
+{
+	int i;
+
+	for (i = 0; i < ARRAY_SIZE(netlink_groups); i++) {
+		netlink_fds[i].dispatch_size = sizeof(route_dispatch) / sizeof(route_dispatch[0]);
+		netlink_fds[i].dispatch = route_dispatch;
+		if (!netlink_open(loop, &netlink_fds[i], NETLINK_ROUTE,
+				  netlink_groups[i]))
+			goto err_close_all;
+	}
+
+	netlink_enumerate(&talk_fd, PF_UNSPEC, RTM_GETLINK);
+	netlink_read_cb(loop, &talk_fd.io, EV_READ);
+
+	netlink_enumerate(&talk_fd, PF_UNSPEC, RTM_GETADDR);
+	netlink_read_cb(loop, &talk_fd.io, EV_READ);
+
+	/* man page netlink(7) says that first created netlink socket will
+	 * get the getpid() assigned as nlmsg_pid. This is our talk_fd.
+	 *
+	 * Our route callbacks will ignore route changes made by ourselves
+	 * (nlmsg_pid == getpid()) but we still need to get the initial
+	 * route enumration. Therefore we use another netlink socket to
+	 * "pretend" that it was not us who created those routes and the
+	 * route callback will pick them up.
+	 */
+	netlink_enumerate(&netlink_fds[1], PF_UNSPEC, RTM_GETROUTE);
+	netlink_read_cb(loop, &talk_fd.io, EV_READ);
+
+	return TRUE;
+
+err_close_all:
+	for (i = 0; i < ARRAY_SIZE(netlink_groups); i++)
+		netlink_close(loop, &netlink_fds[i]);
+
+	return FALSE;
+}
+
+void kernel_cleanup_iface_routes(struct pingu_iface *iface)
+{
+	int err = 0;
+	if (iface->has_route_rule) {
+		err = netlink_rule_del(&talk_fd, iface);
+		if (err == 0)
+			iface->has_route_rule = 0;
+		if (err > 0)
+			log_error("Failed to delete route rule for %s", iface->name);
+		netlink_route_flush(&talk_fd, iface);
+	}
+}
+
+void kernel_close(void)
+{
+	int i;
+	for (i = 0; i < ARRAY_SIZE(netlink_groups); i++)
+		netlink_close(NULL, &netlink_fds[i]);
+}
+