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ntp: reconnect client sockets

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With separate client sockets, allow the initial connect() to fail (e.g.
when the network is not reachable yet) and try to connect later when
sending the packet.

Also, reconnect the socket when the local address has changed.
This commit is contained in:
Miroslav Lichvar 2014-08-04 15:49:29 +02:00
parent 17d944c333
commit 43cca04c33
1 changed files with 69 additions and 20 deletions
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89
ntp_io.c
View file

@ -244,6 +244,23 @@ prepare_socket(int family, int port_number, int client_only)
/* ================================================== */
static int
prepare_separate_client_socket(int family)
{
switch (family) {
case IPADDR_INET4:
return prepare_socket(AF_INET, 0, 1);
#ifdef HAVE_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)
{
@ -273,7 +290,7 @@ connect_socket(int sock_fd, NTP_Remote_Address *remote_addr)
}
if (connect(sock_fd, &addr.u, addr_len) < 0) {
LOG(LOGS_ERR, LOGF_NtpIO, "Could not connect NTP socket to %s:%d : %s",
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;
@ -296,6 +313,39 @@ close_socket(int sock_fd)
/* ================================================== */
static int
reconnect_socket(int sock_fd, NTP_Remote_Address *remote_addr)
{
int fd;
assert(separate_client_sockets && sock_fd != INVALID_SOCK_FD &&
!NIO_IsServerSocket(sock_fd));
DEBUG_LOG(LOGF_NtpIO, "Reconnecting socket %d to %s:%d", sock_fd,
UTI_IPToString(&remote_addr->ip_addr), remote_addr->port);
/* Get a new client socket */
fd = prepare_separate_client_socket(remote_addr->ip_addr.family);
if (fd == INVALID_SOCK_FD)
return 0;
/* Try to connect */
if (!connect_socket(fd, remote_addr)) {
close_socket(fd);
return 0;
}
/* Replace the original socket */
if (dup2(fd, sock_fd) != sock_fd) {
DEBUG_LOG(LOGF_NtpIO, "Could not duplicate socket : %s", strerror(errno));
return 0;
}
close_socket(fd);
return 1;
}
/* ================================================== */
void
NIO_Initialise(int family)
{
@ -379,28 +429,14 @@ int
NIO_GetClientSocket(NTP_Remote_Address *remote_addr)
{
if (separate_client_sockets) {
int sock_fd;
switch (remote_addr->ip_addr.family) {
case IPADDR_INET4:
sock_fd = prepare_socket(AF_INET, 0, 1);
break;
#ifdef HAVE_IPV6
case IPADDR_INET6:
sock_fd = prepare_socket(AF_INET6, 0, 1);
break;
#endif
default:
sock_fd = INVALID_SOCK_FD;
}
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;
}
/* Try to connect the socket, if it fails (e.g. there is no route
to the address yet), we'll try again later */
connect_socket(sock_fd, remote_addr);
return sock_fd;
} else {
@ -578,7 +614,7 @@ send_packet(void *packet, int packetlen, NTP_Remote_Address *remote_addr, NTP_Lo
struct msghdr msg;
struct iovec iov;
char cmsgbuf[256];
int cmsglen;
int cmsglen, reconnect;
socklen_t addrlen = 0;
assert(initialised);
@ -671,6 +707,9 @@ send_packet(void *packet, int packetlen, NTP_Remote_Address *remote_addr, NTP_Lo
}
#endif
reconnect = 0;
try_again:
DEBUG_LOG(LOGF_NtpIO, "Sending to %s:%d from %s fd %d",
UTI_IPToString(&remote_addr->ip_addr), remote_addr->port,
UTI_IPToString(&local_addr->ip_addr), local_addr->sock_fd);
@ -681,8 +720,18 @@ send_packet(void *packet, int packetlen, NTP_Remote_Address *remote_addr, NTP_Lo
msg.msg_control = NULL;
if (sendmsg(local_addr->sock_fd, &msg, 0) < 0) {
/* If this is a separate client socket, try to reconnect it (but no more
than once) if not connected yet or if it may be bound to an address that
is no longer valid */
reconnect = !reconnect && separate_client_sockets && !addrlen &&
(errno == ENOTCONN || errno == EDESTADDRREQ || errno == EINVAL);
DEBUG_LOG(LOGF_NtpIO, "Could not send to %s:%d : %s",
UTI_IPToString(&remote_addr->ip_addr), remote_addr->port, strerror(errno));
/* Try sending the packet again if reconnect succeeds */
if (reconnect && reconnect_socket(local_addr->sock_fd, remote_addr))
goto try_again;
}
}