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qemu/net/socket.c
Stefan Hajnoczi fc13fa00ea net: ensure "socket" backend uses non-blocking fds 
There are several code paths in net_init_socket() depending on how the
socket is created: file descriptor passing, UDP multicast, TCP, or UDP.
Some of these support both listen and connect.

Not all code paths set the socket to non-blocking.  This patch addresses
the file descriptor passing and UDP cases which were missing
socket_set_nonblock(fd) calls.

I considered moving socket_set_nonblock(fd) to a central location but it
turns out the code paths are different enough to require non-blocking at
different places.

Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com>
2013-04-02 11:47:37 -04:00

761 lines
21 KiB
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/*
* QEMU System Emulator
*
* Copyright (c) 2003-2008 Fabrice Bellard
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*/
#include "config-host.h"
#include "net/net.h"
#include "clients.h"
#include "monitor/monitor.h"
#include "qemu-common.h"
#include "qemu/error-report.h"
#include "qemu/option.h"
#include "qemu/sockets.h"
#include "qemu/iov.h"
typedef struct NetSocketState {
NetClientState nc;
int listen_fd;
int fd;
int state; /* 0 = getting length, 1 = getting data */
unsigned int index;
unsigned int packet_len;
unsigned int send_index; /* number of bytes sent (only SOCK_STREAM) */
uint8_t buf[NET_BUFSIZE];
struct sockaddr_in dgram_dst; /* contains inet host and port destination iff connectionless (SOCK_DGRAM) */
IOHandler *send_fn; /* differs between SOCK_STREAM/SOCK_DGRAM */
bool read_poll; /* waiting to receive data? */
bool write_poll; /* waiting to transmit data? */
} NetSocketState;
static void net_socket_accept(void *opaque);
static void net_socket_writable(void *opaque);
/* Only read packets from socket when peer can receive them */
static int net_socket_can_send(void *opaque)
{
NetSocketState *s = opaque;
return qemu_can_send_packet(&s->nc);
}
static void net_socket_update_fd_handler(NetSocketState *s)
{
qemu_set_fd_handler2(s->fd,
s->read_poll ? net_socket_can_send : NULL,
s->read_poll ? s->send_fn : NULL,
s->write_poll ? net_socket_writable : NULL,
s);
}
static void net_socket_read_poll(NetSocketState *s, bool enable)
{
s->read_poll = enable;
net_socket_update_fd_handler(s);
}
static void net_socket_write_poll(NetSocketState *s, bool enable)
{
s->write_poll = enable;
net_socket_update_fd_handler(s);
}
static void net_socket_writable(void *opaque)
{
NetSocketState *s = opaque;
net_socket_write_poll(s, false);
qemu_flush_queued_packets(&s->nc);
}
static ssize_t net_socket_receive(NetClientState *nc, const uint8_t *buf, size_t size)
{
NetSocketState *s = DO_UPCAST(NetSocketState, nc, nc);
uint32_t len = htonl(size);
struct iovec iov[] = {
{
.iov_base = &len,
.iov_len = sizeof(len),
}, {
.iov_base = (void *)buf,
.iov_len = size,
},
};
size_t remaining;
ssize_t ret;
remaining = iov_size(iov, 2) - s->send_index;
ret = iov_send(s->fd, iov, 2, s->send_index, remaining);
if (ret == -1 && errno == EAGAIN) {
ret = 0; /* handled further down */
}
if (ret == -1) {
s->send_index = 0;
return -errno;
}
if (ret < (ssize_t)remaining) {
s->send_index += ret;
net_socket_write_poll(s, true);
return 0;
}
s->send_index = 0;
return size;
}
static ssize_t net_socket_receive_dgram(NetClientState *nc, const uint8_t *buf, size_t size)
{
NetSocketState *s = DO_UPCAST(NetSocketState, nc, nc);
ssize_t ret;
do {
ret = qemu_sendto(s->fd, buf, size, 0,
(struct sockaddr *)&s->dgram_dst,
sizeof(s->dgram_dst));
} while (ret == -1 && errno == EINTR);
if (ret == -1 && errno == EAGAIN) {
net_socket_write_poll(s, true);
return 0;
}
return ret;
}
static void net_socket_send(void *opaque)
{
NetSocketState *s = opaque;
int size, err;
unsigned l;
uint8_t buf1[NET_BUFSIZE];
const uint8_t *buf;
size = qemu_recv(s->fd, buf1, sizeof(buf1), 0);
if (size < 0) {
err = socket_error();
if (err != EWOULDBLOCK)
goto eoc;
} else if (size == 0) {
/* end of connection */
eoc:
net_socket_read_poll(s, false);
net_socket_write_poll(s, false);
if (s->listen_fd != -1) {
qemu_set_fd_handler(s->listen_fd, net_socket_accept, NULL, s);
}
closesocket(s->fd);
s->fd = -1;
s->state = 0;
s->index = 0;
s->packet_len = 0;
s->nc.link_down = true;
memset(s->buf, 0, sizeof(s->buf));
memset(s->nc.info_str, 0, sizeof(s->nc.info_str));
return;
}
buf = buf1;
while (size > 0) {
/* reassemble a packet from the network */
switch(s->state) {
case 0:
l = 4 - s->index;
if (l > size)
l = size;
memcpy(s->buf + s->index, buf, l);
buf += l;
size -= l;
s->index += l;
if (s->index == 4) {
/* got length */
s->packet_len = ntohl(*(uint32_t *)s->buf);
s->index = 0;
s->state = 1;
}
break;
case 1:
l = s->packet_len - s->index;
if (l > size)
l = size;
if (s->index + l <= sizeof(s->buf)) {
memcpy(s->buf + s->index, buf, l);
} else {
fprintf(stderr, "serious error: oversized packet received,"
"connection terminated.\n");
s->state = 0;
goto eoc;
}
s->index += l;
buf += l;
size -= l;
if (s->index >= s->packet_len) {
qemu_send_packet(&s->nc, s->buf, s->packet_len);
s->index = 0;
s->state = 0;
}
break;
}
}
}
static void net_socket_send_dgram(void *opaque)
{
NetSocketState *s = opaque;
int size;
size = qemu_recv(s->fd, s->buf, sizeof(s->buf), 0);
if (size < 0)
return;
if (size == 0) {
/* end of connection */
net_socket_read_poll(s, false);
net_socket_write_poll(s, false);
return;
}
qemu_send_packet(&s->nc, s->buf, size);
}
static int net_socket_mcast_create(struct sockaddr_in *mcastaddr, struct in_addr *localaddr)
{
struct ip_mreq imr;
int fd;
int val, ret;
#ifdef __OpenBSD__
unsigned char loop;
#else
int loop;
#endif
if (!IN_MULTICAST(ntohl(mcastaddr->sin_addr.s_addr))) {
fprintf(stderr, "qemu: error: specified mcastaddr \"%s\" (0x%08x) "
"does not contain a multicast address\n",
inet_ntoa(mcastaddr->sin_addr),
(int)ntohl(mcastaddr->sin_addr.s_addr));
return -1;
}
fd = qemu_socket(PF_INET, SOCK_DGRAM, 0);
if (fd < 0) {
perror("socket(PF_INET, SOCK_DGRAM)");
return -1;
}
val = 1;
ret = qemu_setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, &val, sizeof(val));
if (ret < 0) {
perror("setsockopt(SOL_SOCKET, SO_REUSEADDR)");
goto fail;
}
ret = bind(fd, (struct sockaddr *)mcastaddr, sizeof(*mcastaddr));
if (ret < 0) {
perror("bind");
goto fail;
}
/* Add host to multicast group */
imr.imr_multiaddr = mcastaddr->sin_addr;
if (localaddr) {
imr.imr_interface = *localaddr;
} else {
imr.imr_interface.s_addr = htonl(INADDR_ANY);
}
ret = qemu_setsockopt(fd, IPPROTO_IP, IP_ADD_MEMBERSHIP,
&imr, sizeof(struct ip_mreq));
if (ret < 0) {
perror("setsockopt(IP_ADD_MEMBERSHIP)");
goto fail;
}
/* Force mcast msgs to loopback (eg. several QEMUs in same host */
loop = 1;
ret = qemu_setsockopt(fd, IPPROTO_IP, IP_MULTICAST_LOOP,
&loop, sizeof(loop));
if (ret < 0) {
perror("setsockopt(SOL_IP, IP_MULTICAST_LOOP)");
goto fail;
}
/* If a bind address is given, only send packets from that address */
if (localaddr != NULL) {
ret = qemu_setsockopt(fd, IPPROTO_IP, IP_MULTICAST_IF,
localaddr, sizeof(*localaddr));
if (ret < 0) {
perror("setsockopt(IP_MULTICAST_IF)");
goto fail;
}
}
qemu_set_nonblock(fd);
return fd;
fail:
if (fd >= 0)
closesocket(fd);
return -1;
}
static void net_socket_cleanup(NetClientState *nc)
{
NetSocketState *s = DO_UPCAST(NetSocketState, nc, nc);
if (s->fd != -1) {
net_socket_read_poll(s, false);
net_socket_write_poll(s, false);
close(s->fd);
s->fd = -1;
}
if (s->listen_fd != -1) {
qemu_set_fd_handler(s->listen_fd, NULL, NULL, NULL);
closesocket(s->listen_fd);
s->listen_fd = -1;
}
}
static NetClientInfo net_dgram_socket_info = {
.type = NET_CLIENT_OPTIONS_KIND_SOCKET,
.size = sizeof(NetSocketState),
.receive = net_socket_receive_dgram,
.cleanup = net_socket_cleanup,
};
static NetSocketState *net_socket_fd_init_dgram(NetClientState *peer,
const char *model,
const char *name,
int fd, int is_connected)
{
struct sockaddr_in saddr;
int newfd;
socklen_t saddr_len;
NetClientState *nc;
NetSocketState *s;
/* fd passed: multicast: "learn" dgram_dst address from bound address and save it
* Because this may be "shared" socket from a "master" process, datagrams would be recv()
* by ONLY ONE process: we must "clone" this dgram socket --jjo
*/
if (is_connected) {
if (getsockname(fd, (struct sockaddr *) &saddr, &saddr_len) == 0) {
/* must be bound */
if (saddr.sin_addr.s_addr == 0) {
fprintf(stderr, "qemu: error: init_dgram: fd=%d unbound, "
"cannot setup multicast dst addr\n", fd);
goto err;
}
/* clone dgram socket */
newfd = net_socket_mcast_create(&saddr, NULL);
if (newfd < 0) {
/* error already reported by net_socket_mcast_create() */
goto err;
}
/* clone newfd to fd, close newfd */
dup2(newfd, fd);
close(newfd);
} else {
fprintf(stderr,
"qemu: error: init_dgram: fd=%d failed getsockname(): %s\n",
fd, strerror(errno));
goto err;
}
}
nc = qemu_new_net_client(&net_dgram_socket_info, peer, model, name);
snprintf(nc->info_str, sizeof(nc->info_str),
"socket: fd=%d (%s mcast=%s:%d)",
fd, is_connected ? "cloned" : "",
inet_ntoa(saddr.sin_addr), ntohs(saddr.sin_port));
s = DO_UPCAST(NetSocketState, nc, nc);
s->fd = fd;
s->listen_fd = -1;
s->send_fn = net_socket_send_dgram;
net_socket_read_poll(s, true);
/* mcast: save bound address as dst */
if (is_connected) {
s->dgram_dst = saddr;
}
return s;
err:
closesocket(fd);
return NULL;
}
static void net_socket_connect(void *opaque)
{
NetSocketState *s = opaque;
s->send_fn = net_socket_send;
net_socket_read_poll(s, true);
}
static NetClientInfo net_socket_info = {
.type = NET_CLIENT_OPTIONS_KIND_SOCKET,
.size = sizeof(NetSocketState),
.receive = net_socket_receive,
.cleanup = net_socket_cleanup,
};
static NetSocketState *net_socket_fd_init_stream(NetClientState *peer,
const char *model,
const char *name,
int fd, int is_connected)
{
NetClientState *nc;
NetSocketState *s;
nc = qemu_new_net_client(&net_socket_info, peer, model, name);
snprintf(nc->info_str, sizeof(nc->info_str), "socket: fd=%d", fd);
s = DO_UPCAST(NetSocketState, nc, nc);
s->fd = fd;
s->listen_fd = -1;
/* Disable Nagle algorithm on TCP sockets to reduce latency */
socket_set_nodelay(fd);
if (is_connected) {
net_socket_connect(s);
} else {
qemu_set_fd_handler(s->fd, NULL, net_socket_connect, s);
}
return s;
}
static NetSocketState *net_socket_fd_init(NetClientState *peer,
const char *model, const char *name,
int fd, int is_connected)
{
int so_type = -1, optlen=sizeof(so_type);
if(getsockopt(fd, SOL_SOCKET, SO_TYPE, (char *)&so_type,
(socklen_t *)&optlen)< 0) {
fprintf(stderr, "qemu: error: getsockopt(SO_TYPE) for fd=%d failed\n",
fd);
closesocket(fd);
return NULL;
}
switch(so_type) {
case SOCK_DGRAM:
return net_socket_fd_init_dgram(peer, model, name, fd, is_connected);
case SOCK_STREAM:
return net_socket_fd_init_stream(peer, model, name, fd, is_connected);
default:
/* who knows ... this could be a eg. a pty, do warn and continue as stream */
fprintf(stderr, "qemu: warning: socket type=%d for fd=%d is not SOCK_DGRAM or SOCK_STREAM\n", so_type, fd);
return net_socket_fd_init_stream(peer, model, name, fd, is_connected);
}
return NULL;
}
static void net_socket_accept(void *opaque)
{
NetSocketState *s = opaque;
struct sockaddr_in saddr;
socklen_t len;
int fd;
for(;;) {
len = sizeof(saddr);
fd = qemu_accept(s->listen_fd, (struct sockaddr *)&saddr, &len);
if (fd < 0 && errno != EINTR) {
return;
} else if (fd >= 0) {
qemu_set_fd_handler(s->listen_fd, NULL, NULL, NULL);
break;
}
}
s->fd = fd;
s->nc.link_down = false;
net_socket_connect(s);
snprintf(s->nc.info_str, sizeof(s->nc.info_str),
"socket: connection from %s:%d",
inet_ntoa(saddr.sin_addr), ntohs(saddr.sin_port));
}
static int net_socket_listen_init(NetClientState *peer,
const char *model,
const char *name,
const char *host_str)
{
NetClientState *nc;
NetSocketState *s;
struct sockaddr_in saddr;
int fd, val, ret;
if (parse_host_port(&saddr, host_str) < 0)
return -1;
fd = qemu_socket(PF_INET, SOCK_STREAM, 0);
if (fd < 0) {
perror("socket");
return -1;
}
qemu_set_nonblock(fd);
/* allow fast reuse */
val = 1;
qemu_setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, &val, sizeof(val));
ret = bind(fd, (struct sockaddr *)&saddr, sizeof(saddr));
if (ret < 0) {
perror("bind");
closesocket(fd);
return -1;
}
ret = listen(fd, 0);
if (ret < 0) {
perror("listen");
closesocket(fd);
return -1;
}
nc = qemu_new_net_client(&net_socket_info, peer, model, name);
s = DO_UPCAST(NetSocketState, nc, nc);
s->fd = -1;
s->listen_fd = fd;
s->nc.link_down = true;
qemu_set_fd_handler(s->listen_fd, net_socket_accept, NULL, s);
return 0;
}
static int net_socket_connect_init(NetClientState *peer,
const char *model,
const char *name,
const char *host_str)
{
NetSocketState *s;
int fd, connected, ret, err;
struct sockaddr_in saddr;
if (parse_host_port(&saddr, host_str) < 0)
return -1;
fd = qemu_socket(PF_INET, SOCK_STREAM, 0);
if (fd < 0) {
perror("socket");
return -1;
}
qemu_set_nonblock(fd);
connected = 0;
for(;;) {
ret = connect(fd, (struct sockaddr *)&saddr, sizeof(saddr));
if (ret < 0) {
err = socket_error();
if (err == EINTR || err == EWOULDBLOCK) {
} else if (err == EINPROGRESS) {
break;
#ifdef _WIN32
} else if (err == WSAEALREADY || err == WSAEINVAL) {
break;
#endif
} else {
perror("connect");
closesocket(fd);
return -1;
}
} else {
connected = 1;
break;
}
}
s = net_socket_fd_init(peer, model, name, fd, connected);
if (!s)
return -1;
snprintf(s->nc.info_str, sizeof(s->nc.info_str),
"socket: connect to %s:%d",
inet_ntoa(saddr.sin_addr), ntohs(saddr.sin_port));
return 0;
}
static int net_socket_mcast_init(NetClientState *peer,
const char *model,
const char *name,
const char *host_str,
const char *localaddr_str)
{
NetSocketState *s;
int fd;
struct sockaddr_in saddr;
struct in_addr localaddr, *param_localaddr;
if (parse_host_port(&saddr, host_str) < 0)
return -1;
if (localaddr_str != NULL) {
if (inet_aton(localaddr_str, &localaddr) == 0)
return -1;
param_localaddr = &localaddr;
} else {
param_localaddr = NULL;
}
fd = net_socket_mcast_create(&saddr, param_localaddr);
if (fd < 0)
return -1;
s = net_socket_fd_init(peer, model, name, fd, 0);
if (!s)
return -1;
s->dgram_dst = saddr;
snprintf(s->nc.info_str, sizeof(s->nc.info_str),
"socket: mcast=%s:%d",
inet_ntoa(saddr.sin_addr), ntohs(saddr.sin_port));
return 0;
}
static int net_socket_udp_init(NetClientState *peer,
const char *model,
const char *name,
const char *rhost,
const char *lhost)
{
NetSocketState *s;
int fd, val, ret;
struct sockaddr_in laddr, raddr;
if (parse_host_port(&laddr, lhost) < 0) {
return -1;
}
if (parse_host_port(&raddr, rhost) < 0) {
return -1;
}
fd = qemu_socket(PF_INET, SOCK_DGRAM, 0);
if (fd < 0) {
perror("socket(PF_INET, SOCK_DGRAM)");
return -1;
}
val = 1;
ret = qemu_setsockopt(fd, SOL_SOCKET, SO_REUSEADDR,
&val, sizeof(val));
if (ret < 0) {
perror("setsockopt(SOL_SOCKET, SO_REUSEADDR)");
closesocket(fd);
return -1;
}
ret = bind(fd, (struct sockaddr *)&laddr, sizeof(laddr));
if (ret < 0) {
perror("bind");
closesocket(fd);
return -1;
}
qemu_set_nonblock(fd);
s = net_socket_fd_init(peer, model, name, fd, 0);
if (!s) {
return -1;
}
s->dgram_dst = raddr;
snprintf(s->nc.info_str, sizeof(s->nc.info_str),
"socket: udp=%s:%d",
inet_ntoa(raddr.sin_addr), ntohs(raddr.sin_port));
return 0;
}
int net_init_socket(const NetClientOptions *opts, const char *name,
NetClientState *peer)
{
const NetdevSocketOptions *sock;
assert(opts->kind == NET_CLIENT_OPTIONS_KIND_SOCKET);
sock = opts->socket;
if (sock->has_fd + sock->has_listen + sock->has_connect + sock->has_mcast +
sock->has_udp != 1) {
error_report("exactly one of fd=, listen=, connect=, mcast= or udp="
" is required");
return -1;
}
if (sock->has_localaddr && !sock->has_mcast && !sock->has_udp) {
error_report("localaddr= is only valid with mcast= or udp=");
return -1;
}
if (sock->has_fd) {
int fd;
fd = monitor_handle_fd_param(cur_mon, sock->fd);
if (fd == -1) {
return -1;
}
qemu_set_nonblock(fd);
if (!net_socket_fd_init(peer, "socket", name, fd, 1)) {
return -1;
}
return 0;
}
if (sock->has_listen) {
if (net_socket_listen_init(peer, "socket", name, sock->listen) == -1) {
return -1;
}
return 0;
}
if (sock->has_connect) {
if (net_socket_connect_init(peer, "socket", name, sock->connect) ==
-1) {
return -1;
}
return 0;
}
if (sock->has_mcast) {
/* if sock->localaddr is missing, it has been initialized to "all bits
* zero" */
if (net_socket_mcast_init(peer, "socket", name, sock->mcast,
sock->localaddr) == -1) {
return -1;
}
return 0;
}
assert(sock->has_udp);
if (!sock->has_localaddr) {
error_report("localaddr= is mandatory with udp=");
return -1;
}
if (net_socket_udp_init(peer, "socket", name, sock->udp, sock->localaddr) ==
-1) {
return -1;
}
return 0;
}
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