Discussion:
[PATCH v4] NTP implementation for IPv6 timeserver
(too old to reply)
Naveen Singh
2015-10-30 04:19:37 UTC
Permalink
From: nasingh <***@nasingh-vm.roam.corp.google.com>

Current NTP code is written with an assumption that timeserver is
always an IPv4 address. If there is an IPv6 timeserver then the socket
operation would fail with error as Permission denied (13). This change
in ntp.c ensures that code works fine with both IPv4 and IPv6 address.
---
src/ntp.c | 131 ++++++++++++++++++++++++++++++++++++++++++++++----------------
1 file changed, 98 insertions(+), 33 deletions(-)

diff --git a/src/ntp.c b/src/ntp.c
index 2c313a4..9e7192d 100644
--- a/src/ntp.c
+++ b/src/ntp.c
@@ -18,7 +18,6 @@
* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
*
*/
-
#ifdef HAVE_CONFIG_H
#include <config.h>
#endif
@@ -34,6 +33,7 @@
#include <netinet/in.h>
#include <netinet/ip.h>
#include <arpa/inet.h>
+#include <netdb.h>

#include <glib.h>

@@ -117,12 +117,12 @@ static struct timespec mtx_time;
static int transmit_fd = 0;

static char *timeserver = NULL;
-static struct sockaddr_in timeserver_addr;
+static struct sockaddr_in6 timeserver_addr;
static gint poll_id = 0;
static gint timeout_id = 0;
static guint retries = 0;

-static void send_packet(int fd, const char *server, uint32_t timeout);
+static void send_packet(int fd, struct sockaddr *server, uint32_t timeout);

static void next_server(void)
{
@@ -143,17 +143,19 @@ static gboolean send_timeout(gpointer user_data)
if (retries++ == NTP_SEND_RETRIES)
next_server();
else
- send_packet(transmit_fd, timeserver, timeout << 1);
+ send_packet(transmit_fd, (struct sockaddr *)&timeserver_addr, timeout << 1);

return FALSE;
}

-static void send_packet(int fd, const char *server, uint32_t timeout)
+static void send_packet(int fd, struct sockaddr *server, uint32_t timeout)
{
struct ntp_msg msg;
- struct sockaddr_in addr;
struct timeval transmit_timeval;
ssize_t len;
+ void * addr;
+ int size;
+ char ipaddrstring[INET6_ADDRSTRLEN + 1];

/*
* At some point, we could specify the actual system precision with:
@@ -168,10 +170,16 @@ static void send_packet(int fd, const char *server, uint32_t timeout)
msg.poll = 10; // max
msg.precision = NTP_PRECISION_S;

- memset(&addr, 0, sizeof(addr));
- addr.sin_family = AF_INET;
- addr.sin_port = htons(123);
- addr.sin_addr.s_addr = inet_addr(server);
+ if (server->sa_family == AF_INET) {
+ size = sizeof(struct sockaddr_in);
+ addr = (void *)&(((struct sockaddr_in *)&timeserver_addr)->sin_addr);
+ } else if (server->sa_family == AF_INET6) {
+ size = sizeof(struct sockaddr_in6);
+ addr = (void *)&timeserver_addr.sin6_addr;
+ } else {
+ connman_error("Family is neither ipv4 nor ipv6");
+ return;
+ }

gettimeofday(&transmit_timeval, NULL);
clock_gettime(CLOCK_MONOTONIC, &mtx_time);
@@ -180,10 +188,12 @@ static void send_packet(int fd, const char *server, uint32_t timeout)
msg.xmttime.fraction = htonl(transmit_timeval.tv_usec * 1000);

len = sendto(fd, &msg, sizeof(msg), MSG_DONTWAIT,
- &addr, sizeof(addr));
+ server, size);
+
if (len < 0) {
connman_error("Time request for server %s failed (%d/%s)",
- server, errno, strerror(errno));
+ inet_ntop(server->sa_family, addr, ipaddrstring, sizeof(ipaddrstring)),
+ errno, strerror(errno));

if (errno == ENETUNREACH)
__connman_timeserver_sync_next();
@@ -192,7 +202,8 @@ static void send_packet(int fd, const char *server, uint32_t timeout)
}

if (len != sizeof(msg)) {
- connman_error("Broken time request for server %s", server);
+ connman_error("Broken time request for server %s",
+ inet_ntop(server->sa_family, addr, ipaddrstring, sizeof(ipaddrstring)));
return;
}

@@ -213,7 +224,7 @@ static gboolean next_poll(gpointer user_data)
if (!timeserver || transmit_fd == 0)
return FALSE;

- send_packet(transmit_fd, timeserver, NTP_SEND_TIMEOUT);
+ send_packet(transmit_fd, (struct sockaddr *)&timeserver_addr, NTP_SEND_TIMEOUT);

return FALSE;
}
@@ -363,7 +374,7 @@ static gboolean received_data(GIOChannel *channel, GIOCondition condition,
gpointer user_data)
{
unsigned char buf[128];
- struct sockaddr_in sender_addr;
+ struct sockaddr_in6 sender_addr;
struct msghdr msg;
struct iovec iov;
struct cmsghdr *cmsg;
@@ -372,6 +383,9 @@ static gboolean received_data(GIOChannel *channel, GIOCondition condition,
char aux[128];
ssize_t len;
int fd;
+ int size;
+ void * addr_ptr;
+ void * src_ptr;

if (condition & (G_IO_HUP | G_IO_ERR | G_IO_NVAL)) {
connman_error("Problem with timer server channel");
@@ -396,8 +410,20 @@ static gboolean received_data(GIOChannel *channel, GIOCondition condition,
if (len < 0)
return TRUE;

- if (timeserver_addr.sin_addr.s_addr != sender_addr.sin_addr.s_addr)
- /* only accept messages from the timeserver */
+ if (sender_addr.sin6_family == AF_INET) {
+ size = 4;
+ addr_ptr = &((struct sockaddr_in *)&timeserver_addr)->sin_addr;
+ src_ptr = &((struct sockaddr_in *)&sender_addr)->sin_addr;
+ } else if (sender_addr.sin6_family == AF_INET6) {
+ size = 16;
+ addr_ptr = &((struct sockaddr_in6 *)&timeserver_addr)->sin6_addr;
+ src_ptr = &((struct sockaddr_in6 *)&sender_addr)->sin6_addr;
+ } else {
+ connman_error("Not a valid family type");
+ return TRUE;
+ }
+
+ if(memcmp(addr_ptr, src_ptr, size) != 0)
return TRUE;

tv = NULL;
@@ -422,36 +448,76 @@ static gboolean received_data(GIOChannel *channel, GIOCondition condition,
static void start_ntp(char *server)
{
GIOChannel *channel;
- struct sockaddr_in addr;
+ struct addrinfo hint;
+ struct addrinfo *info;
+ struct sockaddr * addr;
+ struct sockaddr_in * in4addr;
+ struct sockaddr_in6 in6addr;
+ int size;
+ int family;
int tos = IPTOS_LOWDELAY, timestamp = 1;
+ int ret;

if (!server)
return;

- DBG("server %s", server);
+ memset(&hint, 0, sizeof(hint));
+ hint.ai_family = AF_UNSPEC;
+ hint.ai_socktype = SOCK_DGRAM;
+ hint.ai_flags = AI_NUMERICHOST | AI_PASSIVE;
+ ret = getaddrinfo(server, NULL, &hint, &info);

- if (channel_watch > 0)
- goto send;
+ if (ret) {
+ connman_error("cannot get server info");
+ return;
+ }

- transmit_fd = socket(PF_INET, SOCK_DGRAM | SOCK_CLOEXEC, 0);
- if (transmit_fd < 0) {
- connman_error("Failed to open time server socket");
+ family = info->ai_family;
+
+ memcpy(&timeserver_addr, info->ai_addr, info->ai_addrlen);
+ memset(&in6addr, 0, sizeof(in6addr));
+
+ if (family == AF_INET) {
+ ((struct sockaddr_in *)&timeserver_addr)->sin_port = htons(123);
+ in4addr = (struct sockaddr_in *)&in6addr;
+ in4addr->sin_family = family;
+ addr = (struct sockaddr *)in4addr;
+ size = sizeof(struct sockaddr_in);
+ } else if (family == AF_INET6) {
+ timeserver_addr.sin6_port = htons(123);
+ in6addr.sin6_family = family;
+ addr = (struct sockaddr *)&in6addr;
+ size = sizeof(in6addr);
+ } else {
+ connman_error("Family is neither ipv4 nor ipv6");
return;
}
+ freeaddrinfo(info);
+
+ DBG("server %s family %d", server, family);
+
+ if (channel_watch > 0)
+ goto send;

- memset(&addr, 0, sizeof(addr));
- addr.sin_family = AF_INET;
+ transmit_fd = socket(family, SOCK_DGRAM | SOCK_CLOEXEC, 0);

- if (bind(transmit_fd, (struct sockaddr *) &addr, sizeof(addr)) < 0) {
+ if (transmit_fd <= 0) {
+ connman_error("Failed to open time server socket");
+ return;
+ }
+
+ if (bind(transmit_fd, (struct sockaddr *) addr, size) < 0) {
connman_error("Failed to bind time server socket");
close(transmit_fd);
return;
}

- if (setsockopt(transmit_fd, IPPROTO_IP, IP_TOS, &tos, sizeof(tos)) < 0) {
- connman_error("Failed to set type of service option");
- close(transmit_fd);
- return;
+ if (family == AF_INET) {
+ if (setsockopt(transmit_fd, IPPROTO_IP, IP_TOS, &tos, sizeof(tos)) < 0) {
+ connman_error("Failed to set type of service option");
+ close(transmit_fd);
+ return;
+ }
}

if (setsockopt(transmit_fd, SOL_SOCKET, SO_TIMESTAMP, &timestamp,
@@ -479,7 +545,7 @@ static void start_ntp(char *server)
g_io_channel_unref(channel);

send:
- send_packet(transmit_fd, server, NTP_SEND_TIMEOUT);
+ send_packet(transmit_fd, (struct sockaddr*)&timeserver_addr, NTP_SEND_TIMEOUT);
}

int __connman_ntp_start(char *server)
@@ -493,7 +559,6 @@ int __connman_ntp_start(char *server)
g_free(timeserver);

timeserver = g_strdup(server);
- timeserver_addr.sin_addr.s_addr = inet_addr(server);

start_ntp(timeserver);
--
2.6.0.rc2.230.g3dd15c0
Loading...