6to4: Add 6to4 tunnel support.

Netlink support routines taken from iproute2 package.
Iproute2 source code can be found at
git://git.kernel.org/pub/scm/linux/kernel/git/shemminger/iproute2.git

1 files changed, 497 insertions, 0 deletions

diff --git a/src/6to4.c b/src/6to4.c
new file mode 100644
index 00000000..767c8662
--- /dev/null
+++ b/src/6to4.c
@@ -0,0 +1,497 @@
+/*
+ *
+ *  Connection Manager
+ *
+ *  Copyright (C) 2011  Nokia Corporation. All rights reserved.
+ *  Copyright (C) Alexey Kuznetsov et al. from iproute2 package.
+ *
+ *  This program is free software; you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License version 2 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.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program; if not, write to the Free Software
+ *  Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+ *
+ */
+
+#ifdef HAVE_CONFIG_H
+#include <config.h>
+#endif
+
+#include <stdio.h>
+#include <string.h>
+#include <sys/socket.h>
+#include <netinet/in.h>
+#include <arpa/inet.h>
+#include <net/if.h>
+#include <linux/ip.h>
+#include <linux/if_tunnel.h>
+#include <linux/netlink.h>
+#include <linux/rtnetlink.h>
+#include <sys/ioctl.h>
+#include <unistd.h>
+
+#include "connman.h"
+#include <connman/log.h>
+#include <connman/ipconfig.h>
+
+static int tunnel_created;
+static int tunnel_pending;
+static char *tunnel_ip_address;
+
+#define NLMSG_TAIL(nmsg) \
+	((struct rtattr *) (((void *)(nmsg)) + NLMSG_ALIGN((nmsg)->nlmsg_len)))
+
+#ifndef IP_DF
+#define IP_DF		0x4000		/* Flag: "Don't Fragment"	*/
+#endif
+
+struct rtnl_handle {
+	int			fd;
+	struct sockaddr_nl	local;
+	struct sockaddr_nl	peer;
+	__u32			seq;
+	__u32			dump;
+};
+
+static int addattr32(struct nlmsghdr *n, int maxlen, int type, __u32 data)
+{
+	int len = RTA_LENGTH(4);
+	struct rtattr *rta;
+	if (NLMSG_ALIGN(n->nlmsg_len) + len > (unsigned int)maxlen) {
+		DBG("Error! max allowed bound %d exceeded", maxlen);
+		return -1;
+	}
+	rta = NLMSG_TAIL(n);
+	rta->rta_type = type;
+	rta->rta_len = len;
+	memcpy(RTA_DATA(rta), &data, 4);
+	n->nlmsg_len = NLMSG_ALIGN(n->nlmsg_len) + len;
+
+	return 0;
+}
+
+static int addattr_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) >
+					(unsigned int)maxlen) {
+		DBG("addattr_l message exceeded bound of %d", maxlen);
+		return -1;
+	}
+	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 0;
+}
+
+static void rtnl_close(struct rtnl_handle *rth)
+{
+	if (rth->fd >= 0) {
+		close(rth->fd);
+		rth->fd = -1;
+	}
+}
+
+static int rtnl_open(struct rtnl_handle *rth)
+{
+	socklen_t addr_len;
+	int sndbuf = 1024;
+
+	memset(rth, 0, sizeof(*rth));
+
+	rth->fd = socket(AF_NETLINK, SOCK_RAW, NETLINK_ROUTE);
+	if (rth->fd < 0) {
+		connman_error("Can not open netlink socket: %s",
+						strerror(errno));
+		return -1;
+	}
+
+	if (setsockopt(rth->fd, SOL_SOCKET, SO_SNDBUF, &sndbuf,
+			sizeof(sndbuf)) < 0) {
+		connman_error("SO_SNDBUF: %s", strerror(errno));
+		return -1;
+	}
+
+	memset(&rth->local, 0, sizeof(rth->local));
+	rth->local.nl_family = AF_NETLINK;
+	rth->local.nl_groups = 0;
+
+	if (bind(rth->fd, (struct sockaddr *)&rth->local,
+			sizeof(rth->local)) < 0) {
+		connman_error("Can not bind netlink socket: %s",
+							strerror(errno));
+		return -1;
+	}
+	addr_len = sizeof(rth->local);
+	if (getsockname(rth->fd, (struct sockaddr *)&rth->local,
+				&addr_len) < 0) {
+		connman_error("Can not getsockname: %s", strerror(errno));
+		return -1;
+	}
+	if (addr_len != sizeof(rth->local)) {
+		connman_error("Wrong address length %d", addr_len);
+		return -1;
+	}
+	if (rth->local.nl_family != AF_NETLINK) {
+		connman_error("Wrong address family %d", rth->local.nl_family);
+		return -1;
+	}
+	rth->seq = time(NULL);
+
+	return 0;
+}
+
+static int rtnl_talk(struct rtnl_handle *rtnl, struct nlmsghdr *n)
+{
+	struct sockaddr_nl nladdr;
+	struct iovec iov = {
+		.iov_base = (void *)n,
+		.iov_len = n->nlmsg_len
+	};
+	struct msghdr msg = {
+		.msg_name = &nladdr,
+		.msg_namelen = sizeof(nladdr),
+		.msg_iov = &iov,
+		.msg_iovlen = 1,
+	};
+	unsigned seq;
+	int err;
+
+	memset(&nladdr, 0, sizeof(nladdr));
+	nladdr.nl_family = AF_NETLINK;
+
+	n->nlmsg_seq = seq = ++rtnl->seq;
+	n->nlmsg_flags |= NLM_F_ACK;
+
+	err = sendmsg(rtnl->fd, &msg, 0);
+	if (err < 0) {
+		connman_error("Can not talk to rtnetlink");
+		return err;
+	}
+
+	return 0;
+}
+
+static int tunnel_create(struct in_addr *addr)
+{
+	struct ip_tunnel_parm p;
+	struct ifreq ifr;
+	int fd = -1;
+	int ret;
+
+	/* ip tunnel add tun6to4 mode sit remote any local 1.2.3.4 ttl 64 */
+
+	memset(&p, 0, sizeof(struct ip_tunnel_parm));
+	memset(&ifr, 0, sizeof(struct ifreq));
+
+	p.iph.version = 4;
+	p.iph.ihl = 5;
+	p.iph.frag_off = htons(IP_DF);
+	p.iph.protocol = IPPROTO_IPV6;
+	p.iph.saddr = addr->s_addr;
+	p.iph.ttl = 64;
+	strncpy(p.name, "tun6to4", IFNAMSIZ);
+
+	strncpy(ifr.ifr_name, "sit0", IFNAMSIZ);
+	ifr.ifr_ifru.ifru_data = (void *)&p;
+	fd = socket(AF_INET, SOCK_DGRAM, 0);
+	ret = ioctl(fd, SIOCADDTUNNEL, &ifr);
+	if (ret)
+		connman_error("add tunnel %s failed: %s", ifr.ifr_name,
+							strerror(errno));
+	close(fd);
+
+	return ret;
+}
+
+static void tunnel_destroy()
+{
+	struct ip_tunnel_parm p;
+	struct ifreq ifr;
+	int fd = -1;
+	int ret;
+
+	if (tunnel_created == 0)
+		return;
+
+	/* ip tunnel del tun6to4 */
+
+	memset(&p, 0, sizeof(struct ip_tunnel_parm));
+	memset(&ifr, 0, sizeof(struct ifreq));
+
+	p.iph.version = 4;
+	p.iph.ihl = 5;
+	p.iph.protocol = IPPROTO_IPV6;
+	strncpy(p.name, "tun6to4", IFNAMSIZ);
+
+	strncpy(ifr.ifr_name, "tun6to4", IFNAMSIZ);
+	ifr.ifr_ifru.ifru_data = (void *)&p;
+	fd = socket(AF_INET, SOCK_DGRAM, 0);
+	if (fd < 0) {
+		connman_error("socket failed: %s", strerror(errno));
+		return;
+	}
+
+	ret = ioctl(fd, SIOCDELTUNNEL, &ifr);
+	if (ret)
+		connman_error("del tunnel %s failed: %s", ifr.ifr_name,
+							strerror(errno));
+	else
+		tunnel_created = 0;
+
+	tunnel_pending = 0;
+	close(fd);
+
+	g_free(tunnel_ip_address);
+	tunnel_ip_address = NULL;
+}
+
+static int tunnel_add_route()
+{
+	struct rtnl_handle rth;
+	struct in6_addr addr6;
+	int index;
+	int ret = 0;
+
+	struct {
+		struct nlmsghdr n;
+		struct rtmsg 	r;
+		char   		buf[1024];
+	} req;
+
+	/* ip -6 route add ::/0 via ::192.88.99.1 dev tun6to4 metric 1 */
+
+	index = if_nametoindex("tun6to4");
+	if (index == 0) {
+		DBG("Can not find device tun6to4");
+		return -1;
+	}
+
+	memset(&req, 0, sizeof(req));
+
+	req.n.nlmsg_len = NLMSG_LENGTH(sizeof(struct rtmsg));
+	req.n.nlmsg_flags = NLM_F_REQUEST | NLM_F_CREATE | NLM_F_EXCL;
+	req.n.nlmsg_type = RTM_NEWROUTE;
+	req.r.rtm_family = AF_INET6;
+	req.r.rtm_table = RT_TABLE_MAIN;
+	req.r.rtm_protocol = RTPROT_BOOT;
+	req.r.rtm_scope = RT_SCOPE_UNIVERSE;
+	req.r.rtm_type = RTN_UNICAST;
+	req.r.rtm_dst_len = 0;
+
+	inet_pton(AF_INET6, "::192.88.99.1", &addr6);
+
+	addattr_l(&req.n, sizeof(req), RTA_GATEWAY, &addr6.s6_addr, 16);
+	addattr32(&req.n, sizeof(req), RTA_OIF, index);
+	addattr32(&req.n, sizeof(req), RTA_PRIORITY, 1);
+
+	ret = rtnl_open(&rth);
+	if (ret < 0)
+		goto done;
+
+	ret = rtnl_talk(&rth, &req.n);
+
+done:
+	rtnl_close(&rth);
+	return ret;
+}
+
+static int tunnel_set_addr(unsigned int a, unsigned int b,
+			unsigned int c, unsigned int d)
+{
+	struct rtnl_handle rth;
+	struct in6_addr addr6;
+	char *ip6addr;
+	int ret;
+
+	struct {
+		struct nlmsghdr n;
+		struct ifaddrmsg ifa;
+		char buf[256];
+	} req;
+
+	/* ip -6 addr add dev tun6to4 2002:0102:0304::1/64 */
+
+	memset(&req, 0, sizeof(req));
+
+	req.n.nlmsg_len = NLMSG_LENGTH(sizeof(struct ifaddrmsg));
+	req.n.nlmsg_flags = NLM_F_REQUEST | NLM_F_CREATE | NLM_F_EXCL;
+	req.n.nlmsg_type = RTM_NEWADDR;
+	req.ifa.ifa_family = AF_INET6;
+	req.ifa.ifa_prefixlen = 64;
+	req.ifa.ifa_index = if_nametoindex("tun6to4");
+	if (req.ifa.ifa_index == 0) {
+		connman_error("Can not find device tun6to4");
+		ret = -1;
+		goto done;
+	}
+
+	ip6addr = g_strdup_printf("2002:%02x%02x:%02x%02x::1", a, b, c, d);
+	inet_pton(AF_INET6, ip6addr, &addr6);
+	DBG("ipv6 address %s", ip6addr);
+	g_free(ip6addr);
+
+	addattr_l(&req.n, sizeof(req), IFA_LOCAL, &addr6.s6_addr, 16);
+	addattr_l(&req.n, sizeof(req), IFA_ADDRESS, &addr6.s6_addr, 16);
+
+	ret = rtnl_open(&rth);
+	if (ret < 0)
+		goto done;
+
+	ret = rtnl_talk(&rth, &req.n);
+
+done:
+	rtnl_close(&rth);
+	return ret;
+}
+
+static int init_6to4(struct in_addr *ip4addr)
+{
+	unsigned int a, b, c, d;
+	in_addr_t addr;
+	int ret;
+
+	DBG("");
+
+	addr = ntohl(ip4addr->s_addr);
+
+	a = (addr & 0xff000000) >> 24;
+	b = (addr & 0x00ff0000) >> 16;
+	c = (addr & 0x0000ff00) >> 8;
+	d = addr & 0x000000ff;
+
+	ret = tunnel_create(ip4addr);
+	if (ret)
+		return -1;
+
+	tunnel_created = 1;
+
+	ret = connman_inet_setup_tunnel("tun6to4", 1472);
+	if (ret)
+		goto error;
+
+	ret = tunnel_set_addr(a, b, c, d);
+	if (ret)
+		goto error;
+
+	ret = tunnel_add_route();
+	if (ret)
+		goto error;
+
+	tunnel_pending = 0;
+	return 0;
+
+error:
+	tunnel_destroy();
+	return -1;
+}
+
+static void receive_rs_reply(struct nd_router_advert *reply, void *user_data)
+{
+	char *address = user_data;
+	struct in_addr ip4addr;
+
+	DBG("reply %p address %s", reply, address);
+
+	/* We try to create tunnel if autoconfiguration did not work i.e.,
+	 * we did not receive any reply to router solicitation message.
+	 */
+	if (reply == NULL && inet_aton(address, &ip4addr) != 0)
+		init_6to4(&ip4addr);
+
+	g_free(address);
+}
+
+int __connman_6to4_probe(struct connman_service *service)
+{
+	struct connman_ipconfig *ip4config, *ip6config;
+	enum connman_ipconfig_method method;
+	unsigned int a, b, c, d;
+	struct in_addr ip4addr;
+	in_addr_t addr;
+	const char *address;
+	char *ip_address;
+	int index;
+
+	DBG("service %p", service);
+
+	if (tunnel_created || tunnel_pending)
+		return 0;
+
+	if (service == NULL)
+		return -1;
+
+	ip4config = __connman_service_get_ip4config(service);
+	if (ip4config == NULL)
+		return -1;
+
+	ip6config = __connman_service_get_ip6config(service);
+	if (ip6config == NULL)
+		return -1;
+
+	method = __connman_ipconfig_get_method(ip6config);
+	if (method != CONNMAN_IPCONFIG_METHOD_AUTO)
+		return -1;
+
+	address = __connman_ipconfig_get_local(ip4config);
+	if (address == NULL)
+		return -1;
+
+	if (inet_aton(address, &ip4addr) == 0)
+		return -1;
+
+	addr = ntohl(ip4addr.s_addr);
+
+	a = (addr & 0xff000000) >> 24;
+	b = (addr & 0x00ff0000) >> 16;
+	c = (addr & 0x0000ff00) >> 8;
+	d = addr & 0x000000ff;
+
+	/* 6to4 tunnel is only usable if we have a public IPv4 address */
+	if (a == 10 || (a == 192 && b == 168) ||
+					(a == 172 && (b >= 16 && b <= 31)))
+		return -1;
+
+	index = connman_ipconfig_get_index(ip4config);
+	ip_address = g_strdup(address);
+	tunnel_pending = 1;
+
+	g_free(tunnel_ip_address);
+	tunnel_ip_address = g_strdup(address);
+
+	return __connman_inet_ipv6_send_rs(index, 2, receive_rs_reply,
+							ip_address);
+}
+
+void __connman_6to4_remove(struct connman_ipconfig *ip4config)
+{
+	const char *address;
+
+	DBG("tunnel ip address %s", tunnel_ip_address);
+
+	if (ip4config == NULL)
+		return;
+
+	address = __connman_ipconfig_get_local(ip4config);
+	if (address == NULL)
+		return;
+
+	if (g_strcmp0(address, tunnel_ip_address) != 0)
+		return;
+
+	if (tunnel_created)
+		tunnel_destroy();
+}