--- /dev/null
+/*
+ * Copyright 6WIND S.A., 2014
+ *
+ * This work is licensed under the terms of the GNU GPL, version 2 or
+ * (at your option) any later version. See the COPYING file in the
+ * top-level directory.
+ */
+#include "qemu/osdep.h"
+#include "qemu-common.h"
+#include "qemu/sockets.h"
+
+#include <sys/mman.h>
+#include <sys/socket.h>
+#include <sys/un.h>
+
+#include "ivshmem-server.h"
+
+/* log a message on stdout if verbose=1 */
+#define IVSHMEM_SERVER_DEBUG(server, fmt, ...) do { \
+ if ((server)->verbose) { \
+ printf(fmt, ## __VA_ARGS__); \
+ } \
+ } while (0)
+
+/** maximum size of a huge page, used by ivshmem_server_ftruncate() */
+#define IVSHMEM_SERVER_MAX_HUGEPAGE_SIZE (1024 * 1024 * 1024)
+
+/** default listen backlog (number of sockets not accepted) */
+#define IVSHMEM_SERVER_LISTEN_BACKLOG 10
+
+/* send message to a client unix socket */
+static int
+ivshmem_server_send_one_msg(int sock_fd, int64_t peer_id, int fd)
+{
+ int ret;
+ struct msghdr msg;
+ struct iovec iov[1];
+ union {
+ struct cmsghdr cmsg;
+ char control[CMSG_SPACE(sizeof(int))];
+ } msg_control;
+ struct cmsghdr *cmsg;
+
+ peer_id = GINT64_TO_LE(peer_id);
+ iov[0].iov_base = &peer_id;
+ iov[0].iov_len = sizeof(peer_id);
+
+ memset(&msg, 0, sizeof(msg));
+ msg.msg_iov = iov;
+ msg.msg_iovlen = 1;
+
+ /* if fd is specified, add it in a cmsg */
+ if (fd >= 0) {
+ memset(&msg_control, 0, sizeof(msg_control));
+ msg.msg_control = &msg_control;
+ msg.msg_controllen = sizeof(msg_control);
+ cmsg = CMSG_FIRSTHDR(&msg);
+ cmsg->cmsg_level = SOL_SOCKET;
+ cmsg->cmsg_type = SCM_RIGHTS;
+ cmsg->cmsg_len = CMSG_LEN(sizeof(int));
+ memcpy(CMSG_DATA(cmsg), &fd, sizeof(fd));
+ }
+
+ ret = sendmsg(sock_fd, &msg, 0);
+ if (ret <= 0) {
+ return -1;
+ }
+
+ return 0;
+}
+
+/* free a peer when the server advertises a disconnection or when the
+ * server is freed */
+static void
+ivshmem_server_free_peer(IvshmemServer *server, IvshmemServerPeer *peer)
+{
+ unsigned vector;
+ IvshmemServerPeer *other_peer;
+
+ IVSHMEM_SERVER_DEBUG(server, "free peer %" PRId64 "\n", peer->id);
+ close(peer->sock_fd);
+ QTAILQ_REMOVE(&server->peer_list, peer, next);
+
+ /* advertise the deletion to other peers */
+ QTAILQ_FOREACH(other_peer, &server->peer_list, next) {
+ ivshmem_server_send_one_msg(other_peer->sock_fd, peer->id, -1);
+ }
+
+ for (vector = 0; vector < peer->vectors_count; vector++) {
+ event_notifier_cleanup(&peer->vectors[vector]);
+ }
+
+ g_free(peer);
+}
+
+/* send the peer id and the shm_fd just after a new client connection */
+static int
+ivshmem_server_send_initial_info(IvshmemServer *server, IvshmemServerPeer *peer)
+{
+ int ret;
+
+ /* send our protocol version first */
+ ret = ivshmem_server_send_one_msg(peer->sock_fd, IVSHMEM_PROTOCOL_VERSION,
+ -1);
+ if (ret < 0) {
+ IVSHMEM_SERVER_DEBUG(server, "cannot send version: %s\n",
+ strerror(errno));
+ return -1;
+ }
+
+ /* send the peer id to the client */
+ ret = ivshmem_server_send_one_msg(peer->sock_fd, peer->id, -1);
+ if (ret < 0) {
+ IVSHMEM_SERVER_DEBUG(server, "cannot send peer id: %s\n",
+ strerror(errno));
+ return -1;
+ }
+
+ /* send the shm_fd */
+ ret = ivshmem_server_send_one_msg(peer->sock_fd, -1, server->shm_fd);
+ if (ret < 0) {
+ IVSHMEM_SERVER_DEBUG(server, "cannot send shm fd: %s\n",
+ strerror(errno));
+ return -1;
+ }
+
+ return 0;
+}
+
+/* handle message on listening unix socket (new client connection) */
+static int
+ivshmem_server_handle_new_conn(IvshmemServer *server)
+{
+ IvshmemServerPeer *peer, *other_peer;
+ struct sockaddr_un unaddr;
+ socklen_t unaddr_len;
+ int newfd;
+ unsigned i;
+
+ /* accept the incoming connection */
+ unaddr_len = sizeof(unaddr);
+ newfd = qemu_accept(server->sock_fd,
+ (struct sockaddr *)&unaddr, &unaddr_len);
+
+ if (newfd < 0) {
+ IVSHMEM_SERVER_DEBUG(server, "cannot accept() %s\n", strerror(errno));
+ return -1;
+ }
+
+ qemu_set_nonblock(newfd);
+ IVSHMEM_SERVER_DEBUG(server, "accept()=%d\n", newfd);
+
+ /* allocate new structure for this peer */
+ peer = g_malloc0(sizeof(*peer));
+ peer->sock_fd = newfd;
+
+ /* get an unused peer id */
+ /* XXX: this could use id allocation such as Linux IDA, or simply
+ * a free-list */
+ for (i = 0; i < G_MAXUINT16; i++) {
+ if (ivshmem_server_search_peer(server, server->cur_id) == NULL) {
+ break;
+ }
+ server->cur_id++;
+ }
+ if (i == G_MAXUINT16) {
+ IVSHMEM_SERVER_DEBUG(server, "cannot allocate new client id\n");
+ close(newfd);
+ g_free(peer);
+ return -1;
+ }
+ peer->id = server->cur_id++;
+
+ /* create eventfd, one per vector */
+ peer->vectors_count = server->n_vectors;
+ for (i = 0; i < peer->vectors_count; i++) {
+ if (event_notifier_init(&peer->vectors[i], FALSE) < 0) {
+ IVSHMEM_SERVER_DEBUG(server, "cannot create eventfd\n");
+ goto fail;
+ }
+ }
+
+ /* send peer id and shm fd */
+ if (ivshmem_server_send_initial_info(server, peer) < 0) {
+ IVSHMEM_SERVER_DEBUG(server, "cannot send initial info\n");
+ goto fail;
+ }
+
+ /* advertise the new peer to others */
+ QTAILQ_FOREACH(other_peer, &server->peer_list, next) {
+ for (i = 0; i < peer->vectors_count; i++) {
+ ivshmem_server_send_one_msg(other_peer->sock_fd, peer->id,
+ peer->vectors[i].wfd);
+ }
+ }
+
+ /* advertise the other peers to the new one */
+ QTAILQ_FOREACH(other_peer, &server->peer_list, next) {
+ for (i = 0; i < peer->vectors_count; i++) {
+ ivshmem_server_send_one_msg(peer->sock_fd, other_peer->id,
+ other_peer->vectors[i].wfd);
+ }
+ }
+
+ /* advertise the new peer to itself */
+ for (i = 0; i < peer->vectors_count; i++) {
+ ivshmem_server_send_one_msg(peer->sock_fd, peer->id,
+ event_notifier_get_fd(&peer->vectors[i]));
+ }
+
+ QTAILQ_INSERT_TAIL(&server->peer_list, peer, next);
+ IVSHMEM_SERVER_DEBUG(server, "new peer id = %" PRId64 "\n",
+ peer->id);
+ return 0;
+
+fail:
+ while (i--) {
+ event_notifier_cleanup(&peer->vectors[i]);
+ }
+ close(newfd);
+ g_free(peer);
+ return -1;
+}
+
+/* Try to ftruncate a file to next power of 2 of shmsize.
+ * If it fails; all power of 2 above shmsize are tested until
+ * we reach the maximum huge page size. This is useful
+ * if the shm file is in a hugetlbfs that cannot be truncated to the
+ * shm_size value. */
+static int
+ivshmem_server_ftruncate(int fd, unsigned shmsize)
+{
+ int ret;
+ struct stat mapstat;
+
+ /* align shmsize to next power of 2 */
+ shmsize = pow2ceil(shmsize);
+
+ if (fstat(fd, &mapstat) != -1 && mapstat.st_size == shmsize) {
+ return 0;
+ }
+
+ while (shmsize <= IVSHMEM_SERVER_MAX_HUGEPAGE_SIZE) {
+ ret = ftruncate(fd, shmsize);
+ if (ret == 0) {
+ return ret;
+ }
+ shmsize *= 2;
+ }
+
+ return -1;
+}
+
+/* Init a new ivshmem server */
+int
+ivshmem_server_init(IvshmemServer *server, const char *unix_sock_path,
+ const char *shm_path, bool use_shm_open,
+ size_t shm_size, unsigned n_vectors,
+ bool verbose)
+{
+ int ret;
+
+ memset(server, 0, sizeof(*server));
+ server->verbose = verbose;
+
+ ret = snprintf(server->unix_sock_path, sizeof(server->unix_sock_path),
+ "%s", unix_sock_path);
+ if (ret < 0 || ret >= sizeof(server->unix_sock_path)) {
+ IVSHMEM_SERVER_DEBUG(server, "could not copy unix socket path\n");
+ return -1;
+ }
+ ret = snprintf(server->shm_path, sizeof(server->shm_path),
+ "%s", shm_path);
+ if (ret < 0 || ret >= sizeof(server->shm_path)) {
+ IVSHMEM_SERVER_DEBUG(server, "could not copy shm path\n");
+ return -1;
+ }
+
+ server->use_shm_open = use_shm_open;
+ server->shm_size = shm_size;
+ server->n_vectors = n_vectors;
+
+ QTAILQ_INIT(&server->peer_list);
+
+ return 0;
+}
+
+/* open shm, create and bind to the unix socket */
+int
+ivshmem_server_start(IvshmemServer *server)
+{
+ struct sockaddr_un sun;
+ int shm_fd, sock_fd, ret;
+
+ /* open shm file */
+ if (server->use_shm_open) {
+ IVSHMEM_SERVER_DEBUG(server, "Using POSIX shared memory: %s\n",
+ server->shm_path);
+ shm_fd = shm_open(server->shm_path, O_CREAT | O_RDWR, S_IRWXU);
+ } else {
+ gchar *filename = g_strdup_printf("%s/ivshmem.XXXXXX", server->shm_path);
+ IVSHMEM_SERVER_DEBUG(server, "Using file-backed shared memory: %s\n",
+ server->shm_path);
+ shm_fd = mkstemp(filename);
+ unlink(filename);
+ g_free(filename);
+ }
+
+ if (shm_fd < 0) {
+ fprintf(stderr, "cannot open shm file %s: %s\n", server->shm_path,
+ strerror(errno));
+ return -1;
+ }
+ if (ivshmem_server_ftruncate(shm_fd, server->shm_size) < 0) {
+ fprintf(stderr, "ftruncate(%s) failed: %s\n", server->shm_path,
+ strerror(errno));
+ goto err_close_shm;
+ }
+
+ IVSHMEM_SERVER_DEBUG(server, "create & bind socket %s\n",
+ server->unix_sock_path);
+
+ /* create the unix listening socket */
+ sock_fd = socket(AF_UNIX, SOCK_STREAM, 0);
+ if (sock_fd < 0) {
+ IVSHMEM_SERVER_DEBUG(server, "cannot create socket: %s\n",
+ strerror(errno));
+ goto err_close_shm;
+ }
+
+ sun.sun_family = AF_UNIX;
+ ret = snprintf(sun.sun_path, sizeof(sun.sun_path), "%s",
+ server->unix_sock_path);
+ if (ret < 0 || ret >= sizeof(sun.sun_path)) {
+ IVSHMEM_SERVER_DEBUG(server, "could not copy unix socket path\n");
+ goto err_close_sock;
+ }
+ if (bind(sock_fd, (struct sockaddr *)&sun, sizeof(sun)) < 0) {
+ IVSHMEM_SERVER_DEBUG(server, "cannot connect to %s: %s\n", sun.sun_path,
+ strerror(errno));
+ goto err_close_sock;
+ }
+
+ if (listen(sock_fd, IVSHMEM_SERVER_LISTEN_BACKLOG) < 0) {
+ IVSHMEM_SERVER_DEBUG(server, "listen() failed: %s\n", strerror(errno));
+ goto err_close_sock;
+ }
+
+ server->sock_fd = sock_fd;
+ server->shm_fd = shm_fd;
+
+ return 0;
+
+err_close_sock:
+ close(sock_fd);
+err_close_shm:
+ close(shm_fd);
+ return -1;
+}
+
+/* close connections to clients, the unix socket and the shm fd */
+void
+ivshmem_server_close(IvshmemServer *server)
+{
+ IvshmemServerPeer *peer, *npeer;
+
+ IVSHMEM_SERVER_DEBUG(server, "close server\n");
+
+ QTAILQ_FOREACH_SAFE(peer, &server->peer_list, next, npeer) {
+ ivshmem_server_free_peer(server, peer);
+ }
+
+ unlink(server->unix_sock_path);
+ close(server->sock_fd);
+ close(server->shm_fd);
+ server->sock_fd = -1;
+ server->shm_fd = -1;
+}
+
+/* get the fd_set according to the unix socket and the peer list */
+void
+ivshmem_server_get_fds(const IvshmemServer *server, fd_set *fds, int *maxfd)
+{
+ IvshmemServerPeer *peer;
+
+ if (server->sock_fd == -1) {
+ return;
+ }
+
+ FD_SET(server->sock_fd, fds);
+ if (server->sock_fd >= *maxfd) {
+ *maxfd = server->sock_fd + 1;
+ }
+
+ QTAILQ_FOREACH(peer, &server->peer_list, next) {
+ FD_SET(peer->sock_fd, fds);
+ if (peer->sock_fd >= *maxfd) {
+ *maxfd = peer->sock_fd + 1;
+ }
+ }
+}
+
+/* process incoming messages on the sockets in fd_set */
+int
+ivshmem_server_handle_fds(IvshmemServer *server, fd_set *fds, int maxfd)
+{
+ IvshmemServerPeer *peer, *peer_next;
+
+ if (server->sock_fd < maxfd && FD_ISSET(server->sock_fd, fds) &&
+ ivshmem_server_handle_new_conn(server) < 0 && errno != EINTR) {
+ IVSHMEM_SERVER_DEBUG(server, "ivshmem_server_handle_new_conn() "
+ "failed\n");
+ return -1;
+ }
+
+ QTAILQ_FOREACH_SAFE(peer, &server->peer_list, next, peer_next) {
+ /* any message from a peer socket result in a close() */
+ IVSHMEM_SERVER_DEBUG(server, "peer->sock_fd=%d\n", peer->sock_fd);
+ if (peer->sock_fd < maxfd && FD_ISSET(peer->sock_fd, fds)) {
+ ivshmem_server_free_peer(server, peer);
+ }
+ }
+
+ return 0;
+}
+
+/* lookup peer from its id */
+IvshmemServerPeer *
+ivshmem_server_search_peer(IvshmemServer *server, int64_t peer_id)
+{
+ IvshmemServerPeer *peer;
+
+ QTAILQ_FOREACH(peer, &server->peer_list, next) {
+ if (peer->id == peer_id) {
+ return peer;
+ }
+ }
+ return NULL;
+}
+
+/* dump our info, the list of peers their vectors on stdout */
+void
+ivshmem_server_dump(const IvshmemServer *server)
+{
+ const IvshmemServerPeer *peer;
+ unsigned vector;
+
+ /* dump peers */
+ QTAILQ_FOREACH(peer, &server->peer_list, next) {
+ printf("peer_id = %" PRId64 "\n", peer->id);
+
+ for (vector = 0; vector < peer->vectors_count; vector++) {
+ printf(" vector %d is enabled (fd=%d)\n", vector,
+ event_notifier_get_fd(&peer->vectors[vector]));
+ }
+ }
+}
Code Review / kvmfornfv.git / blobdiff