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client: reconnect with multiple addresses

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Allow multiple hostnames/addresses separated by comma to be specified
with the -h option. Hostnames are resolved to up to 16 addresses. When
connecting to an address fails or no reply is received, try the next
address in the list.

Set the default value for the -h option to 127.0.0.1,::1.
This commit is contained in:
Miroslav Lichvar
2015-08-19 10:19:13 +02:00
parent 7079ca2718
commit 0cc8f68754
4 changed files with 140 additions and 44 deletions
Download Patch File Download Diff File Expand all files Collapse all files

174
client.c
View File

@@ -30,6 +30,7 @@
#include "sysincl.h"
#include "array.h"
#include "candm.h"
#include "logging.h"
#include "memory.h"
@@ -60,7 +61,9 @@ union sockaddr_all {
struct sockaddr sa;
};
static int sock_fd;
static ARR_Instance sockaddrs;
static int sock_fd = -1;
static int quit = 0;
@@ -128,66 +131,119 @@ read_line(void)
}
/* ================================================== */
#define MAX_ADDRESSES 16
static ARR_Instance
get_sockaddrs(const char *hostnames, int port)
{
ARR_Instance addrs;
char *hostname, *s1, *s2;
IPAddr ip_addrs[MAX_ADDRESSES];
union sockaddr_all *addr;
int i;
addrs = ARR_CreateInstance(sizeof (union sockaddr_all));
s1 = Strdup(hostnames);
/* Parse the comma-separated list of hostnames */
for (hostname = s1; hostname && *hostname; hostname = s2) {
s2 = strchr(hostname, ',');
if (s2)
*s2++ = '\0';
/* hostname starting with / is considered a path of Unix domain socket */
if (hostname[0] == '/') {
addr = (union sockaddr_all *)ARR_GetNewElement(addrs);
if (snprintf(addr->un.sun_path, sizeof (addr->un.sun_path), "%s", hostname) >=
sizeof (addr->un.sun_path))
LOG_FATAL(LOGF_Client, "Unix socket path too long");
addr->un.sun_family = AF_UNIX;
} else {
if (DNS_Name2IPAddress(hostname, ip_addrs, MAX_ADDRESSES) != DNS_Success) {
DEBUG_LOG(LOGF_Client, "Could not get IP address for %s", hostname);
break;
}
for (i = 0; i < MAX_ADDRESSES && ip_addrs[i].family != IPADDR_UNSPEC; i++) {
addr = (union sockaddr_all *)ARR_GetNewElement(addrs);
UTI_IPAndPortToSockaddr(&ip_addrs[i], port, (struct sockaddr *)addr);
DEBUG_LOG(LOGF_Client, "Resolved %s to %s", hostname, UTI_IPToString(&ip_addrs[i]));
}
}
}
Free(s1);
return addrs;
}
/* ================================================== */
/* Initialise the socket used to talk to the daemon */
static void
open_io(const char *hostname, int port)
static int
prepare_socket(union sockaddr_all *addr)
{
union sockaddr_all addr;
socklen_t addr_len;
IPAddr ip;
char *dir;
/* hostname starting with / is considered a path of Unix domain socket */
if (hostname[0] == '/') {
if (snprintf(addr.un.sun_path, sizeof (addr.un.sun_path), "%s", hostname) >=
sizeof (addr.un.sun_path))
LOG_FATAL(LOGF_Client, "Unix socket path too long");
addr.un.sun_family = AF_UNIX;
addr_len = sizeof (addr.un);
} else {
/* Note, this call could block for a while */
if (DNS_Name2IPAddress(hostname, &ip, 1) != DNS_Success) {
LOG_FATAL(LOGF_Client, "Could not get IP address for %s", hostname);
}
addr_len = UTI_IPAndPortToSockaddr(&ip, port, &addr.sa);
switch (addr->sa.sa_family) {
case AF_UNIX:
addr_len = sizeof (addr->un);
break;
case AF_INET:
addr_len = sizeof (addr->in4);
break;
#ifdef FEAT_IPV6
case AF_INET6:
addr_len = sizeof (addr->in6);
break;
#endif
default:
assert(0);
}
sock_fd = socket(addr.sa.sa_family, SOCK_DGRAM, 0);
sock_fd = socket(addr->sa.sa_family, SOCK_DGRAM, 0);
if (sock_fd < 0) {
LOG_FATAL(LOGF_Client, "Could not create socket : %s", strerror(errno));
DEBUG_LOG(LOGF_Client, "Could not create socket : %s", strerror(errno));
return 0;
}
if (connect(sock_fd, &addr.sa, addr_len) < 0) {
LOG_FATAL(LOGF_Client, "Could not connect socket : %s", strerror(errno));
if (connect(sock_fd, &addr->sa, addr_len) < 0) {
DEBUG_LOG(LOGF_Client, "Could not connect socket : %s", strerror(errno));
return 0;
}
if (addr.sa.sa_family == AF_UNIX) {
if (addr->sa.sa_family == AF_UNIX) {
struct sockaddr_un sun;
/* Construct path of our socket. Use the same directory as the server
socket and include our process ID to allow multiple chronyc instances
running at the same time. */
dir = UTI_PathToDir(hostname);
if (snprintf(addr.un.sun_path, sizeof (addr.un.sun_path),
"%s/chronyc.%d.sock", dir, getpid()) >= sizeof (addr.un.sun_path))
dir = UTI_PathToDir(addr->un.sun_path);
if (snprintf(sun.sun_path, sizeof (sun.sun_path),
"%s/chronyc.%d.sock", dir, getpid()) >= sizeof (sun.sun_path))
LOG_FATAL(LOGF_Client, "Unix socket path too long");
Free(dir);
addr.un.sun_family = AF_UNIX;
unlink(addr.un.sun_path);
sun.sun_family = AF_UNIX;
unlink(sun.sun_path);
/* Bind the socket to the path */
if (bind(sock_fd, &addr.sa, sizeof (addr.un)) < 0) {
LOG_FATAL(LOGF_Client, "Could not bind socket : %s", strerror(errno));
if (bind(sock_fd, (struct sockaddr *)&sun, sizeof (sun)) < 0) {
DEBUG_LOG(LOGF_Client, "Could not bind socket : %s", strerror(errno));
return 0;
}
/* Allow server without root privileges to send replies to our socket */
if (chmod(addr.un.sun_path, 0666) < 0) {
LOG_FATAL(LOGF_Client, "Could not change socket permissions : %s", strerror(errno));
if (chmod(sun.sun_path, 0666) < 0) {
DEBUG_LOG(LOGF_Client, "Could not change socket permissions : %s", strerror(errno));
return 0;
}
}
return 1;
}
/* ================================================== */
@@ -198,6 +254,9 @@ close_io(void)
union sockaddr_all addr;
socklen_t addr_len = sizeof (addr);
if (sock_fd < 0)
return;
/* Remove our Unix domain socket */
if (getsockname(sock_fd, &addr.sa, &addr_len) < 0)
LOG_FATAL(LOGF_Client, "getsockname() failed : %s", strerror(errno));
@@ -206,6 +265,36 @@ close_io(void)
unlink(addr.un.sun_path);
close(sock_fd);
sock_fd = -1;
}
/* ================================================== */
static int
open_io(void)
{
static unsigned int address_index = 0;
union sockaddr_all *addr;
/* If a socket is already opened, close it and try the next address */
if (sock_fd >= 0) {
close_io();
address_index++;
}
/* Find an address for which a socket can be opened and connected */
for (; address_index < ARR_GetSize(sockaddrs); address_index++) {
addr = (union sockaddr_all *)ARR_GetElement(sockaddrs, address_index);
DEBUG_LOG(LOGF_Client, "Opening connection to %s",
UTI_SockaddrToString(&addr->sa));
if (prepare_socket(addr))
return 1;
close_io();
}
return 0;
}
/* ================================================== */
@@ -1463,7 +1552,10 @@ request_reply(CMD_Request *request, CMD_Reply *reply, int requested_reply, int v
int reply_auth_ok;
int status;
if (!submit_request(request, reply, &reply_auth_ok)) {
while (!submit_request(request, reply, &reply_auth_ok)) {
/* Try connecting to other addresses before giving up */
if (open_io())
continue;
printf("506 Cannot talk to daemon\n");
return 0;
}
@@ -2764,7 +2856,7 @@ main(int argc, char **argv)
{
char *line;
const char *progname = argv[0];
const char *hostname = NULL;
const char *hostnames = NULL;
const char *conf_file = DEFAULT_CONF_FILE;
int ret = 1, multi = 0, auto_auth = 0, family = IPADDR_UNSPEC;
int port = DEFAULT_CANDM_PORT;
@@ -2774,7 +2866,7 @@ main(int argc, char **argv)
if (!strcmp(*argv, "-h")) {
++argv, --argc;
if (*argv) {
hostname = *argv;
hostnames = *argv;
}
} else if (!strcmp(*argv, "-p")) {
++argv, --argc;
@@ -2827,8 +2919,8 @@ main(int argc, char **argv)
DNS_SetAddressFamily(family);
if (!hostname) {
hostname = family == IPADDR_INET6 ? "::1" : "127.0.0.1";
if (!hostnames) {
hostnames = "127.0.0.1,::1";
#ifdef FEAT_ASYNCDNS
initial_timeout /= 10;
#endif
@@ -2836,7 +2928,10 @@ main(int argc, char **argv)
UTI_SetQuitSignalsHandler(signal_handler);
open_io(hostname, port);
sockaddrs = get_sockaddrs(hostnames, port);
if (!open_io())
LOG_FATAL(LOGF_Client, "Could not open connection to daemon");
if (auto_auth) {
ret = authenticate_from_config(conf_file);
@@ -2861,6 +2956,7 @@ main(int argc, char **argv)
close_io();
Free(password);
ARR_DestroyInstance(sockaddrs);
return !ret;
}