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chrony/ntp_io.c
Miroslav Lichvar 5214d42c07 ntp: count references to NTP server sockets 
Server sockets are now explicitly opened and closed for normal NTP
server, NTP broadcast and NTP peering. This will allow closing the
NTP port when not needed.
2015-01-06 16:33:49 +01:00

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/*
chronyd/chronyc - Programs for keeping computer clocks accurate.
**********************************************************************
* Copyright (C) Richard P. Curnow 1997-2003
* Copyright (C) Timo Teras 2009
* Copyright (C) Miroslav Lichvar 2009, 2013-2014
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of version 2 of the GNU General Public License 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 Street, Fifth Floor, Boston, MA 02110-1301, USA.
*
**********************************************************************
=======================================================================
This file deals with the IO aspects of reading and writing NTP packets
*/
#include "config.h"
#include "sysincl.h"
#include "ntp_io.h"
#include "ntp_core.h"
#include "ntp_sources.h"
#include "sched.h"
#include "local.h"
#include "logging.h"
#include "conf.h"
#include "util.h"
#define INVALID_SOCK_FD -1
union sockaddr_in46 {
struct sockaddr_in in4;
#ifdef FEAT_IPV6
struct sockaddr_in6 in6;
#endif
struct sockaddr u;
};
/* The server/peer and client sockets for IPv4 and IPv6 */
static int server_sock_fd4;
static int client_sock_fd4;
#ifdef FEAT_IPV6
static int server_sock_fd6;
static int client_sock_fd6;
#endif
/* Reference counters for server sockets to keep them open only when needed */
static int server_sock_ref4;
#ifdef FEAT_IPV6
static int server_sock_ref6;
#endif
/* Flag indicating we create a new connected client socket for each
server instead of sharing client_sock_fd4 and client_sock_fd6 */
static int separate_client_sockets;
/* Flag indicating the server sockets are not created dynamically when needed,
either to have a socket for client requests when separate client sockets
are disabled and client port is equal to server port, or the server port is
disabled */
static int permanent_server_sockets;
/* Flag indicating that we have been initialised */
static int initialised=0;
/* ================================================== */
/* Forward prototypes */
static void read_from_socket(void *anything);
/* ================================================== */
static int
prepare_socket(int family, int port_number, int client_only)
{
union sockaddr_in46 my_addr;
socklen_t my_addr_len;
int sock_fd;
IPAddr bind_address;
int on_off = 1;
/* Open Internet domain UDP socket for NTP message transmissions */
sock_fd = socket(family, SOCK_DGRAM, 0);
if (sock_fd < 0) {
LOG(LOGS_ERR, LOGF_NtpIO, "Could not open %s NTP socket : %s",
family == AF_INET ? "IPv4" : "IPv6", strerror(errno));
return INVALID_SOCK_FD;
}
/* Close on exec */
UTI_FdSetCloexec(sock_fd);
/* Prepare local address */
memset(&my_addr, 0, sizeof (my_addr));
my_addr_len = 0;
switch (family) {
case AF_INET:
if (!client_only)
CNF_GetBindAddress(IPADDR_INET4, &bind_address);
else
CNF_GetBindAcquisitionAddress(IPADDR_INET4, &bind_address);
if (bind_address.family == IPADDR_INET4)
my_addr.in4.sin_addr.s_addr = htonl(bind_address.addr.in4);
else if (port_number)
my_addr.in4.sin_addr.s_addr = htonl(INADDR_ANY);
else
break;
my_addr.in4.sin_family = family;
my_addr.in4.sin_port = htons(port_number);
my_addr_len = sizeof (my_addr.in4);
break;
#ifdef FEAT_IPV6
case AF_INET6:
if (!client_only)
CNF_GetBindAddress(IPADDR_INET6, &bind_address);
else
CNF_GetBindAcquisitionAddress(IPADDR_INET6, &bind_address);
if (bind_address.family == IPADDR_INET6)
memcpy(my_addr.in6.sin6_addr.s6_addr, bind_address.addr.in6,
sizeof (my_addr.in6.sin6_addr.s6_addr));
else if (port_number)
my_addr.in6.sin6_addr = in6addr_any;
else
break;
my_addr.in6.sin6_family = family;
my_addr.in6.sin6_port = htons(port_number);
my_addr_len = sizeof (my_addr.in6);
break;
#endif
default:
assert(0);
}
/* Make the socket capable of re-using an old address if binding to a specific port */
if (port_number &&
setsockopt(sock_fd, SOL_SOCKET, SO_REUSEADDR, (char *)&on_off, sizeof(on_off)) < 0) {
LOG(LOGS_ERR, LOGF_NtpIO, "Could not set reuseaddr socket options");
/* Don't quit - we might survive anyway */
}
/* Make the socket capable of sending broadcast pkts - needed for NTP broadcast mode */
if (!client_only &&
setsockopt(sock_fd, SOL_SOCKET, SO_BROADCAST, (char *)&on_off, sizeof(on_off)) < 0) {
LOG(LOGS_ERR, LOGF_NtpIO, "Could not set broadcast socket options");
/* Don't quit - we might survive anyway */
}
#ifdef SO_TIMESTAMP
/* Enable receiving of timestamp control messages */
if (setsockopt(sock_fd, SOL_SOCKET, SO_TIMESTAMP, (char *)&on_off, sizeof(on_off)) < 0) {
LOG(LOGS_ERR, LOGF_NtpIO, "Could not set timestamp socket options");
/* Don't quit - we might survive anyway */
}
#endif
#ifdef IP_FREEBIND
/* Allow binding to address that doesn't exist yet */
if (my_addr_len > 0 &&
setsockopt(sock_fd, IPPROTO_IP, IP_FREEBIND, (char *)&on_off, sizeof(on_off)) < 0) {
LOG(LOGS_ERR, LOGF_NtpIO, "Could not set free bind socket option");
}
#endif
if (family == AF_INET) {
#ifdef IP_PKTINFO
/* We want the local IP info on server sockets */
if (setsockopt(sock_fd, IPPROTO_IP, IP_PKTINFO, (char *)&on_off, sizeof(on_off)) < 0) {
LOG(LOGS_ERR, LOGF_NtpIO, "Could not set packet info socket option");
/* Don't quit - we might survive anyway */
}
#endif
}
#ifdef FEAT_IPV6
else if (family == AF_INET6) {
#ifdef IPV6_V6ONLY
/* Receive IPv6 packets only */
if (setsockopt(sock_fd, IPPROTO_IPV6, IPV6_V6ONLY, (char *)&on_off, sizeof(on_off)) < 0) {
LOG(LOGS_ERR, LOGF_NtpIO, "Could not set IPV6_V6ONLY socket option");
}
#endif
#ifdef IPV6_RECVPKTINFO
if (setsockopt(sock_fd, IPPROTO_IPV6, IPV6_RECVPKTINFO, (char *)&on_off, sizeof(on_off)) < 0) {
LOG(LOGS_ERR, LOGF_NtpIO, "Could not set IPv6 packet info socket option");
}
#elif defined(IPV6_PKTINFO)
if (setsockopt(sock_fd, IPPROTO_IPV6, IPV6_PKTINFO, (char *)&on_off, sizeof(on_off)) < 0) {
LOG(LOGS_ERR, LOGF_NtpIO, "Could not set IPv6 packet info socket option");
}
#endif
}
#endif
/* Bind the socket if a port or address was specified */
if (my_addr_len > 0 && bind(sock_fd, &my_addr.u, my_addr_len) < 0) {
LOG(LOGS_ERR, LOGF_NtpIO, "Could not bind %s NTP socket : %s",
family == AF_INET ? "IPv4" : "IPv6", strerror(errno));
close(sock_fd);
return INVALID_SOCK_FD;
}
/* Register handler for read events on the socket */
SCH_AddInputFileHandler(sock_fd, read_from_socket, (void *)(long)sock_fd);
return sock_fd;
}
/* ================================================== */
static int
prepare_separate_client_socket(int family)
{
switch (family) {
case IPADDR_INET4:
return prepare_socket(AF_INET, 0, 1);
#ifdef FEAT_IPV6
case IPADDR_INET6:
return prepare_socket(AF_INET6, 0, 1);
#endif
default:
return INVALID_SOCK_FD;
}
}
/* ================================================== */
static int
connect_socket(int sock_fd, NTP_Remote_Address *remote_addr)
{
union sockaddr_in46 addr;
socklen_t addr_len;
addr_len = UTI_IPAndPortToSockaddr(&remote_addr->ip_addr, remote_addr->port, &addr.u);
assert(addr_len);
if (connect(sock_fd, &addr.u, addr_len) < 0) {
DEBUG_LOG(LOGF_NtpIO, "Could not connect NTP socket to %s:%d : %s",
UTI_IPToString(&remote_addr->ip_addr), remote_addr->port,
strerror(errno));
return 0;
}
return 1;
}
/* ================================================== */
static void
close_socket(int sock_fd)
{
if (sock_fd == INVALID_SOCK_FD)
return;
SCH_RemoveInputFileHandler(sock_fd);
close(sock_fd);
}
/* ================================================== */
void
NIO_Initialise(int family)
{
int server_port, client_port;
assert(!initialised);
initialised = 1;
server_port = CNF_GetNTPPort();
client_port = CNF_GetAcquisitionPort();
/* Use separate connected sockets if client port is negative */
separate_client_sockets = client_port < 0;
if (client_port < 0)
client_port = 0;
permanent_server_sockets = !server_port || (!separate_client_sockets &&
client_port == server_port);
server_sock_fd4 = INVALID_SOCK_FD;
client_sock_fd4 = INVALID_SOCK_FD;
server_sock_ref4 = 0;
#ifdef FEAT_IPV6
server_sock_fd6 = INVALID_SOCK_FD;
client_sock_fd6 = INVALID_SOCK_FD;
server_sock_ref6 = 0;
#endif
if (family == IPADDR_UNSPEC || family == IPADDR_INET4) {
if (permanent_server_sockets && server_port)
server_sock_fd4 = prepare_socket(AF_INET, server_port, 0);
if (!separate_client_sockets) {
if (client_port != server_port || !server_port)
client_sock_fd4 = prepare_socket(AF_INET, client_port, 1);
else
client_sock_fd4 = server_sock_fd4;
}
}
#ifdef FEAT_IPV6
if (family == IPADDR_UNSPEC || family == IPADDR_INET6) {
if (permanent_server_sockets && server_port)
server_sock_fd6 = prepare_socket(AF_INET6, server_port, 0);
if (!separate_client_sockets) {
if (client_port != server_port || !server_port)
client_sock_fd6 = prepare_socket(AF_INET6, client_port, 1);
else
client_sock_fd6 = server_sock_fd6;
}
}
#endif
if ((server_port && server_sock_fd4 == INVALID_SOCK_FD &&
permanent_server_sockets
#ifdef FEAT_IPV6
&& server_sock_fd6 == INVALID_SOCK_FD
#endif
) || (!separate_client_sockets && client_sock_fd4 == INVALID_SOCK_FD
#ifdef FEAT_IPV6
&& client_sock_fd6 == INVALID_SOCK_FD
#endif
)) {
LOG_FATAL(LOGF_NtpIO, "Could not open NTP sockets");
}
}
/* ================================================== */
void
NIO_Finalise(void)
{
if (server_sock_fd4 != client_sock_fd4)
close_socket(client_sock_fd4);
close_socket(server_sock_fd4);
server_sock_fd4 = client_sock_fd4 = INVALID_SOCK_FD;
#ifdef FEAT_IPV6
if (server_sock_fd6 != client_sock_fd6)
close_socket(client_sock_fd6);
close_socket(server_sock_fd6);
server_sock_fd6 = client_sock_fd6 = INVALID_SOCK_FD;
#endif
initialised = 0;
}
/* ================================================== */
int
NIO_OpenClientSocket(NTP_Remote_Address *remote_addr)
{
if (separate_client_sockets) {
int sock_fd = prepare_separate_client_socket(remote_addr->ip_addr.family);
if (sock_fd == INVALID_SOCK_FD)
return INVALID_SOCK_FD;
if (!connect_socket(sock_fd, remote_addr)) {
close_socket(sock_fd);
return INVALID_SOCK_FD;
}
return sock_fd;
} else {
switch (remote_addr->ip_addr.family) {
case IPADDR_INET4:
return client_sock_fd4;
#ifdef FEAT_IPV6
case IPADDR_INET6:
return client_sock_fd6;
#endif
default:
return INVALID_SOCK_FD;
}
}
}
/* ================================================== */
int
NIO_OpenServerSocket(NTP_Remote_Address *remote_addr)
{
switch (remote_addr->ip_addr.family) {
case IPADDR_INET4:
if (permanent_server_sockets)
return server_sock_fd4;
if (server_sock_fd4 == INVALID_SOCK_FD)
server_sock_fd4 = prepare_socket(AF_INET, CNF_GetNTPPort(), 0);
if (server_sock_fd4 != INVALID_SOCK_FD)
server_sock_ref4++;
return server_sock_fd4;
#ifdef FEAT_IPV6
case IPADDR_INET6:
if (permanent_server_sockets)
return server_sock_fd6;
if (server_sock_fd6 == INVALID_SOCK_FD)
server_sock_fd6 = prepare_socket(AF_INET6, CNF_GetNTPPort(), 0);
if (server_sock_fd6 != INVALID_SOCK_FD)
server_sock_ref6++;
return server_sock_fd6;
#endif
default:
return INVALID_SOCK_FD;
}
}
/* ================================================== */
void
NIO_CloseClientSocket(int sock_fd)
{
if (separate_client_sockets)
close_socket(sock_fd);
}
/* ================================================== */
void
NIO_CloseServerSocket(int sock_fd)
{
if (permanent_server_sockets || sock_fd == INVALID_SOCK_FD)
return;
if (sock_fd == server_sock_fd4) {
if (--server_sock_ref4 <= 0) {
close_socket(server_sock_fd4);
server_sock_fd4 = INVALID_SOCK_FD;
}
}
#ifdef FEAT_IPV6
else if (sock_fd == server_sock_fd6) {
if (--server_sock_ref6 <= 0) {
close_socket(server_sock_fd6);
server_sock_fd6 = INVALID_SOCK_FD;
}
}
#endif
else {
assert(0);
}
}
/* ================================================== */
int
NIO_IsServerSocket(int sock_fd)
{
return sock_fd != INVALID_SOCK_FD &&
(sock_fd == server_sock_fd4
#ifdef FEAT_IPV6
|| sock_fd == server_sock_fd6
#endif
);
}
/* ================================================== */
static void
read_from_socket(void *anything)
{
/* This should only be called when there is something
to read, otherwise it will block. */
int status, sock_fd;
NTP_Receive_Buffer message;
union sockaddr_in46 where_from;
unsigned int flags = 0;
struct timeval now;
double now_err;
NTP_Remote_Address remote_addr;
NTP_Local_Address local_addr;
char cmsgbuf[256];
struct msghdr msg;
struct iovec iov;
struct cmsghdr *cmsg;
assert(initialised);
SCH_GetLastEventTime(&now, &now_err, NULL);
iov.iov_base = &message.ntp_pkt;
iov.iov_len = sizeof(message);
msg.msg_name = &where_from;
msg.msg_namelen = sizeof(where_from);
msg.msg_iov = &iov;
msg.msg_iovlen = 1;
msg.msg_control = (void *) cmsgbuf;
msg.msg_controllen = sizeof(cmsgbuf);
msg.msg_flags = 0;
sock_fd = (long)anything;
status = recvmsg(sock_fd, &msg, flags);
/* Don't bother checking if read failed or why if it did. More
likely than not, it will be connection refused, resulting from a
previous sendto() directing a datagram at a port that is not
listening (which appears to generate an ICMP response, and on
some architectures e.g. Linux this is translated into an error
reponse on a subsequent recvfrom). */
if (status > 0) {
if (msg.msg_namelen > sizeof (where_from))
LOG_FATAL(LOGF_NtpIO, "Truncated source address");
UTI_SockaddrToIPAndPort(&where_from.u, &remote_addr.ip_addr, &remote_addr.port);
local_addr.ip_addr.family = IPADDR_UNSPEC;
local_addr.sock_fd = sock_fd;
for (cmsg = CMSG_FIRSTHDR(&msg); cmsg; cmsg = CMSG_NXTHDR(&msg, cmsg)) {
#ifdef IP_PKTINFO
if (cmsg->cmsg_level == IPPROTO_IP && cmsg->cmsg_type == IP_PKTINFO) {
struct in_pktinfo ipi;
memcpy(&ipi, CMSG_DATA(cmsg), sizeof(ipi));
local_addr.ip_addr.addr.in4 = ntohl(ipi.ipi_spec_dst.s_addr);
local_addr.ip_addr.family = IPADDR_INET4;
}
#endif
#if defined(IPV6_PKTINFO) && defined(HAVE_IN6_PKTINFO)
if (cmsg->cmsg_level == IPPROTO_IPV6 && cmsg->cmsg_type == IPV6_PKTINFO) {
struct in6_pktinfo ipi;
memcpy(&ipi, CMSG_DATA(cmsg), sizeof(ipi));
memcpy(&local_addr.ip_addr.addr.in6, &ipi.ipi6_addr.s6_addr,
sizeof (local_addr.ip_addr.addr.in6));
local_addr.ip_addr.family = IPADDR_INET6;
}
#endif
#ifdef SO_TIMESTAMP
if (cmsg->cmsg_level == SOL_SOCKET && cmsg->cmsg_type == SO_TIMESTAMP) {
struct timeval tv;
memcpy(&tv, CMSG_DATA(cmsg), sizeof(tv));
LCL_CookTime(&tv, &now, &now_err);
}
#endif
}
if (status > 0) {
DEBUG_LOG(LOGF_NtpIO, "Received %d bytes from %s:%d to %s fd %d",
status,
UTI_IPToString(&remote_addr.ip_addr), remote_addr.port,
UTI_IPToString(&local_addr.ip_addr), local_addr.sock_fd);
}
if (status >= NTP_NORMAL_PACKET_LENGTH) {
NSR_ProcessReceive((NTP_Packet *) &message.ntp_pkt, &now, now_err,
&remote_addr, &local_addr, status);
} else {
/* Just ignore the packet if it's not of a recognized length */
}
}
}
/* ================================================== */
/* Send a packet to remote address from local address */
static int
send_packet(void *packet, int packetlen, NTP_Remote_Address *remote_addr, NTP_Local_Address *local_addr)
{
union sockaddr_in46 remote;
struct msghdr msg;
struct iovec iov;
char cmsgbuf[256];
int cmsglen;
socklen_t addrlen = 0;
assert(initialised);
if (local_addr->sock_fd == INVALID_SOCK_FD) {
DEBUG_LOG(LOGF_NtpIO, "No socket to send to %s:%d",
UTI_IPToString(&remote_addr->ip_addr), remote_addr->port);
return 0;
}
/* Don't set address with connected socket */
if (local_addr->sock_fd == server_sock_fd4 ||
#ifdef FEAT_IPV6
local_addr->sock_fd == server_sock_fd6 ||
#endif
!separate_client_sockets) {
addrlen = UTI_IPAndPortToSockaddr(&remote_addr->ip_addr, remote_addr->port,
&remote.u);
if (!addrlen)
return 0;
}
if (addrlen) {
msg.msg_name = &remote.u;
msg.msg_namelen = addrlen;
} else {
msg.msg_name = NULL;
msg.msg_namelen = 0;
}
iov.iov_base = packet;
iov.iov_len = packetlen;
msg.msg_iov = &iov;
msg.msg_iovlen = 1;
msg.msg_control = cmsgbuf;
msg.msg_controllen = sizeof(cmsgbuf);
msg.msg_flags = 0;
cmsglen = 0;
#ifdef IP_PKTINFO
if (local_addr->ip_addr.family == IPADDR_INET4) {
struct cmsghdr *cmsg;
struct in_pktinfo *ipi;
cmsg = CMSG_FIRSTHDR(&msg);
memset(cmsg, 0, CMSG_SPACE(sizeof(struct in_pktinfo)));
cmsglen += CMSG_SPACE(sizeof(struct in_pktinfo));
cmsg->cmsg_level = IPPROTO_IP;
cmsg->cmsg_type = IP_PKTINFO;
cmsg->cmsg_len = CMSG_LEN(sizeof(struct in_pktinfo));
ipi = (struct in_pktinfo *) CMSG_DATA(cmsg);
ipi->ipi_spec_dst.s_addr = htonl(local_addr->ip_addr.addr.in4);
}
#endif
#if defined(IPV6_PKTINFO) && defined(HAVE_IN6_PKTINFO)
if (local_addr->ip_addr.family == IPADDR_INET6) {
struct cmsghdr *cmsg;
struct in6_pktinfo *ipi;
cmsg = CMSG_FIRSTHDR(&msg);
memset(cmsg, 0, CMSG_SPACE(sizeof(struct in6_pktinfo)));
cmsglen += CMSG_SPACE(sizeof(struct in6_pktinfo));
cmsg->cmsg_level = IPPROTO_IPV6;
cmsg->cmsg_type = IPV6_PKTINFO;
cmsg->cmsg_len = CMSG_LEN(sizeof(struct in6_pktinfo));
ipi = (struct in6_pktinfo *) CMSG_DATA(cmsg);
memcpy(&ipi->ipi6_addr.s6_addr, &local_addr->ip_addr.addr.in6,
sizeof(ipi->ipi6_addr.s6_addr));
}
#endif
msg.msg_controllen = cmsglen;
/* This is apparently required on some systems */
if (!cmsglen)
msg.msg_control = NULL;
if (sendmsg(local_addr->sock_fd, &msg, 0) < 0) {
DEBUG_LOG(LOGF_NtpIO, "Could not send to %s:%d from %s fd %d : %s",
UTI_IPToString(&remote_addr->ip_addr), remote_addr->port,
UTI_IPToString(&local_addr->ip_addr), local_addr->sock_fd,
strerror(errno));
return 0;
}
DEBUG_LOG(LOGF_NtpIO, "Sent %d bytes to %s:%d from %s fd %d", packetlen,
UTI_IPToString(&remote_addr->ip_addr), remote_addr->port,
UTI_IPToString(&local_addr->ip_addr), local_addr->sock_fd);
return 1;
}
/* ================================================== */
/* Send a packet to a given address */
int
NIO_SendPacket(NTP_Packet *packet, NTP_Remote_Address *remote_addr, NTP_Local_Address *local_addr, int length)
{
return send_packet((void *) packet, length, remote_addr, local_addr);
}
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