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tap-vsockd: support daemonization via a --daemon arg

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We daemonize after checking the command-line and binding/connecting
the socket and creating the tap device. Only the ethernet frame
processing happens afterwards.

This patch also includes a new well-known service GUID for the
VPN-proxy ethernet service.

Signed-off-by: David Scott <dave.scott@docker.com>
This commit is contained in:
David Scott 2016-05-14 20:38:56 +01:00
parent f636321b81
commit a1d91d2a3d
1 changed files with 69 additions and 40 deletions
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109
alpine/packages/tap-vsockd/tap-vsockd.c
View File

@ -27,10 +27,12 @@
#include "compat.h"
#include "protocol.h"
int debug_flag = 0;
int daemon_flag = 0;
int listen_flag = 0;
int connect_flag = 0;
char *default_sid = "30D48B34-7D27-4B0B-AAAF-BBBED334DD59";
int alloc_tap(const char *dev) {
int fd;
struct ifreq ifr;
@ -219,7 +221,7 @@ static void* tap_to_vmnet(void *arg)
/* Handle a connection. Handshake with the com.docker.slirp process and start
* exchanging ethernet frames between the socket and the tap device.
*/
static void handle(SOCKET fd, const char *tap)
static void handle(SOCKET fd, char *tap, int tapfd)
{
struct connection connection;
pthread_t v2t, t2v;
@ -231,7 +233,6 @@ static void handle(SOCKET fd, const char *tap)
connection.vif.mac[3], connection.vif.mac[4], connection.vif.mac[5]
);
int tapfd = alloc_tap(tap);
set_macaddr(tap, &connection.vif.mac[0]);
connection.tapfd = tapfd;
@ -311,30 +312,21 @@ static int connect_socket(GUID serviceid) {
return sock;
}
/* Server:
* accept() in an endless loop, handle a connection at a time
*/
static void accept_forever(SOCKET lsock, const char *tap)
{
static int accept_socket(SOCKET lsock) {
SOCKET csock = INVALID_SOCKET;
SOCKADDR_HV sac;
socklen_t socklen = sizeof(sac);
while(1) {
csock = accept(lsock, (struct sockaddr *)&sac, &socklen);
if (csock == INVALID_SOCKET) {
sockerr("accept()");
closesocket(lsock);
exit(1);
}
csock = accept(lsock, (struct sockaddr *)&sac, &socklen);
if (csock == INVALID_SOCKET) {
sockerr("accept()");
closesocket(lsock);
exit(1);
}
printf("Connect from: "GUID_FMT":"GUID_FMT"\n",
GUID_ARGS(sac.VmId), GUID_ARGS(sac.ServiceId));
handle(csock, tap);
closesocket(csock);
}
printf("Connect from: "GUID_FMT":"GUID_FMT"\n",
GUID_ARGS(sac.VmId), GUID_ARGS(sac.ServiceId));
return csock;
}
void write_pidfile(const char *pidfile) {
@ -362,16 +354,44 @@ void write_pidfile(const char *pidfile) {
free(pid_s);
}
void daemonize(const char *pidfile){
pid_t pid = fork ();
if (pid == -1) {
syslog(LOG_CRIT, "Failed to fork()");
exit(1);
}
else if (pid != 0)
exit(0);
if (setsid () == -1) {
syslog(LOG_CRIT, "Failed to setsid()");
exit(1);
}
if (chdir ("/") == -1) {
syslog(LOG_CRIT, "Failed to chdir()");
exit(1);
}
int null = open("/dev/null", O_RDWR);
dup2(null, STDIN_FILENO);
dup2(null, STDOUT_FILENO);
dup2(null, STDERR_FILENO);
close(null);
if (pidfile) write_pidfile(pidfile);
}
void usage(char *name)
{
printf("%s: [--debug] [--tap <name>] [--serviceid <guid>] [--pid <file>]\n", name);
printf("%s usage:\n", name);
printf("\t[--daemon] [--tap <name>] [--serviceid <guid>] [--pid <file>]\n");
printf("\t[--listen | --connect]\n\n");
printf("--debug: log to stderr as well as syslog\n");
printf("--tap <name>: create a tap device with the given name (defaults to eth1)\n");
printf("--serviceid <guid>: use <guid> as the well-known service GUID\n");
printf("--pid <file>: write a pid to the given file\n");
printf("--listen: listen forever for incoming AF_HVSOCK connections\n");
printf("--connect: connect to the parent partition\n");
printf("where\n");
printf("\t--daemonize: run as a background daemon\n");
printf("\t--tap <name>: create a tap device with the given name\n");
printf("\t (defaults to eth1)\n");
printf("\t--serviceid <guid>: use <guid> as the well-known service GUID\n");
printf("\t (defaults to %s)\n", default_sid);
printf("\t--pid <file>: write a pid to the given file\n");
printf("\t--listen: listen forever for incoming AF_HVSOCK connections\n");
printf("\t--connect: connect to the parent partition\n");
}
int __cdecl main(int argc, char **argv)
@ -380,7 +400,7 @@ int __cdecl main(int argc, char **argv)
GUID sid;
int c;
/* Defaults to a testing GUID */
char *serviceid = "3049197C-9A4E-4FBF-9367-97F792F16994";
char *serviceid = default_sid;
char *tap = "eth1";
char *pidfile = NULL;
@ -388,7 +408,7 @@ int __cdecl main(int argc, char **argv)
while (1) {
static struct option long_options[] = {
/* These options set a flag. */
{"debug", no_argument, &debug_flag, 1},
{"daemon", no_argument, &daemon_flag, 1},
{"serviceid", required_argument, NULL, 's'},
{"tap", required_argument, NULL, 't'},
{"pidfile", required_argument, NULL, 'p'},
@ -403,7 +423,7 @@ int __cdecl main(int argc, char **argv)
switch (c) {
case 'd':
debug_flag = 1;
daemon_flag = 1;
break;
case 's':
serviceid = optarg;
@ -425,8 +445,12 @@ int __cdecl main(int argc, char **argv)
fprintf(stderr, "Please supply either the --listen or --connect flag, but not both.\n");
exit(1);
}
if (daemon_flag && !pidfile){
fprintf(stderr, "For daemon mode, please supply a --pidfile argument.\n");
exit(1);
}
int log_flags = LOG_CONS | LOG_NDELAY;
if (debug_flag) {
if (!daemon_flag) {
log_flags |= LOG_PERROR;
}
openlog(argv[0], log_flags, LOG_DAEMON);
@ -438,14 +462,19 @@ int __cdecl main(int argc, char **argv)
exit(1);
}
SOCKET sock = INVALID_SOCKET;
if (listen_flag) {
syslog(LOG_INFO, "starting in listening mode with serviceid=%s and tap=%s", serviceid, tap);
int socket = create_listening_socket(sid);
accept_forever(socket, tap);
exit(0);
SOCKET lsocket = create_listening_socket(sid);
sock = accept_socket(lsocket);
} else {
syslog(LOG_INFO, "starting in connect mode with serviceid=%s and tap=%s", serviceid, tap);
sock = connect_socket(sid);
}
syslog(LOG_INFO, "starting in connect mode with serviceid=%s and tap=%s", serviceid, tap);
int socket = connect_socket(sid);
handle(socket, tap);
return 0;
/* Bring up the tap device before we daemonize */
int tapfd = alloc_tap(tap);
if (daemon_flag) daemonize(pidfile);
handle(sock, tap, tapfd);
exit(0);
}