[RFCLAT#3] Move the tun interface setup from clatd to netd
This is a preparation for reducing the clatd required capability.
Function change:
- configure_tun_ip(), detect_mtu() are moved to netd/ClatdController
- move Clatd_Config.ipv4_local_subnet setup from configure_tun_ip() to
main() because configure_tun_ip() is removed. translate.c needs
the clat IPv4 address for 4->6, 6>->4 address translation.
Bug: 212345928
Test: manual test
1. Connect to ipv6-only wifi.
2. Try IPv4 traffic.
$ ping 8.8.8.8
Change-Id: Ibf80b17865f414f329ab7c50836595f3b99360e2
diff --git a/clatd.c b/clatd.c
index 6a0a0d8..865a568 100644
--- a/clatd.c
+++ b/clatd.c
@@ -104,37 +104,6 @@
return 1;
}
-/* function: configure_tun_ip
- * configures the ipv4 and ipv6 addresses on the tunnel interface
- * tunnel - tun device data
- * mtu - mtu of tun device
- */
-void configure_tun_ip(const struct tun_data *tunnel, const char *v4_addr, int mtu) {
- if (!v4_addr || !inet_pton(AF_INET, v4_addr, &Global_Clatd_Config.ipv4_local_subnet.s_addr)) {
- logmsg(ANDROID_LOG_FATAL, "Invalid IPv4 address %s", v4_addr);
- exit(1);
- }
-
- char addrstr[INET_ADDRSTRLEN];
- inet_ntop(AF_INET, &Global_Clatd_Config.ipv4_local_subnet, addrstr, sizeof(addrstr));
- logmsg(ANDROID_LOG_INFO, "Using IPv4 address %s on %s", addrstr, tunnel->device4);
-
- // Configure the interface before bringing it up. As soon as we bring the interface up, the
- // framework will be notified and will assume the interface's configuration has been finalized.
- int status = add_address(tunnel->device4, AF_INET, &Global_Clatd_Config.ipv4_local_subnet, 32,
- &Global_Clatd_Config.ipv4_local_subnet);
- if (status < 0) {
- logmsg(ANDROID_LOG_FATAL, "configure_tun_ip/if_address(4) failed: %s", strerror(-status));
- exit(1);
- }
-
- status = if_up(tunnel->device4, mtu);
- if (status < 0) {
- logmsg(ANDROID_LOG_FATAL, "configure_tun_ip/if_up(4) failed: %s", strerror(-status));
- exit(1);
- }
-}
-
/* function: set_capability
* set the permitted, effective and inheritable capabilities of the current
* thread
@@ -230,76 +199,21 @@
return 1;
}
-int detect_mtu(const struct in6_addr *plat_subnet, uint32_t plat_suffix, uint32_t mark) {
- // Create an IPv6 UDP socket.
- int s = socket(AF_INET6, SOCK_DGRAM | SOCK_CLOEXEC, 0);
- if (s < 0) {
- logmsg(ANDROID_LOG_FATAL, "socket(AF_INET6, SOCK_DGRAM, 0) failed");
- exit(1);
- }
-
- // Socket's mark affects routing decisions (network selection)
- if ((mark != MARK_UNSET) && setsockopt(s, SOL_SOCKET, SO_MARK, &mark, sizeof(mark))) {
- logmsg(ANDROID_LOG_FATAL, "setsockopt(SOL_SOCKET, SO_MARK) failed: %s", strerror(errno));
- exit(1);
- }
-
- // Try to connect udp socket to plat_subnet(96 bits):plat_suffix(32 bits)
- struct sockaddr_in6 dst = {
- .sin6_family = AF_INET6,
- .sin6_addr = *plat_subnet,
- };
- dst.sin6_addr.s6_addr32[3] = plat_suffix;
- if (connect(s, (struct sockaddr *)&dst, sizeof(dst))) {
- logmsg(ANDROID_LOG_FATAL, "connect() failed: %s", strerror(errno));
- exit(1);
- }
-
- // Fetch the socket's IPv6 mtu - this is effectively fetching mtu from routing table
- int mtu;
- socklen_t sz_mtu = sizeof(mtu);
- if (getsockopt(s, SOL_IPV6, IPV6_MTU, &mtu, &sz_mtu)) {
- logmsg(ANDROID_LOG_FATAL, "getsockopt(SOL_IPV6, IPV6_MTU) failed: %s", strerror(errno));
- exit(1);
- }
- if (sz_mtu != sizeof(mtu)) {
- logmsg(ANDROID_LOG_FATAL, "getsockopt(SOL_IPV6, IPV6_MTU) returned unexpected size: %d",
- sz_mtu);
- exit(1);
- }
- close(s);
-
- return mtu;
-}
-
/* function: configure_interface
* reads the configuration and applies it to the interface
* uplink_interface - network interface to use to reach the ipv6 internet
* plat_prefix - PLAT prefix to use
- * v4_addr - the v4 address to use on the tunnel interface
* v6_addr - the v6 address to use on the native interface
* tunnel - tun device data
- * mark - the socket mark to use for the sending raw socket
*/
-void configure_interface(const char *uplink_interface, const char *plat_prefix, const char *v4_addr,
- const char *v6_addr, struct tun_data *tunnel, uint32_t mark) {
+void configure_interface(const char *uplink_interface, const char *plat_prefix, const char *v6_addr,
+ struct tun_data *tunnel) {
Global_Clatd_Config.native_ipv6_interface = uplink_interface;
if (!plat_prefix || inet_pton(AF_INET6, plat_prefix, &Global_Clatd_Config.plat_subnet) <= 0) {
logmsg(ANDROID_LOG_FATAL, "invalid IPv6 address specified for plat prefix: %s", plat_prefix);
exit(1);
}
- int mtu = detect_mtu(&Global_Clatd_Config.plat_subnet, htonl(0x08080808), mark);
- // clamp to minimum ipv6 mtu - this probably cannot ever trigger
- if (mtu < 1280) mtu = 1280;
- // clamp to buffer size
- if (mtu > MAXMTU) mtu = MAXMTU;
- // decrease by ipv6(40) + ipv6 fragmentation header(8) vs ipv4(20) overhead of 28 bytes
- mtu -= MTU_DELTA;
- logmsg(ANDROID_LOG_WARN, "ipv4 mtu is %d", mtu);
-
- configure_tun_ip(tunnel, v4_addr, mtu);
-
if (!configure_clat_ipv6_address(tunnel, uplink_interface, v6_addr)) {
exit(1);
}
diff --git a/clatd.h b/clatd.h
index 21f3c95..a42768c 100644
--- a/clatd.h
+++ b/clatd.h
@@ -38,15 +38,13 @@
extern volatile sig_atomic_t running;
-void configure_tun_ip(const struct tun_data *tunnel, const char *v4_addr, int mtu);
void set_capability(uint64_t target_cap);
void drop_root_and_caps();
int ipv6_address_changed(const char *interface);
int configure_clat_ipv6_address(const struct tun_data *tunnel, const char *interface,
const char *src_addr);
-int detect_mtu(const struct in6_addr *plat_subnet, uint32_t plat_suffix, uint32_t mark);
-void configure_interface(const char *uplink_interface, const char *plat_prefix, const char *v4_addr,
- const char *v6, struct tun_data *tunnel, uint32_t mark);
+void configure_interface(const char *uplink_interface, const char *plat_prefix, const char *v6,
+ struct tun_data *tunnel);
void event_loop(struct tun_data *tunnel);
/* function: parse_int
diff --git a/main.c b/main.c
index 96fbd0d..fe88dfd 100644
--- a/main.c
+++ b/main.c
@@ -145,12 +145,17 @@
exit(1);
}
+ if (!v4_addr || !inet_pton(AF_INET, v4_addr, &Global_Clatd_Config.ipv4_local_subnet.s_addr)) {
+ logmsg(ANDROID_LOG_FATAL, "Invalid IPv4 address %s", v4_addr);
+ exit(1);
+ }
+
logmsg(ANDROID_LOG_INFO, "Starting clat version %s on %s mark=%s plat=%s v4=%s v6=%s",
CLATD_VERSION, uplink_interface, mark_str ? mark_str : "(none)",
plat_prefix ? plat_prefix : "(none)", v4_addr ? v4_addr : "(none)",
v6_addr ? v6_addr : "(none)");
- configure_interface(uplink_interface, plat_prefix, v4_addr, v6_addr, &tunnel, mark);
+ configure_interface(uplink_interface, plat_prefix, v6_addr, &tunnel);
// run under a regular user with no capabilities
drop_root_and_caps();