diff options
Diffstat (limited to 'tools/xcs/xcs.c')
| -rw-r--r-- | tools/xcs/xcs.c | 880 |
1 files changed, 880 insertions, 0 deletions
diff --git a/tools/xcs/xcs.c b/tools/xcs/xcs.c new file mode 100644 index 0000000000..f0b1a96a88 --- /dev/null +++ b/tools/xcs/xcs.c @@ -0,0 +1,880 @@ +/* xcs.c + * + * xcs - Xen Control Switch + * + * Copyright (c) 2004, Andrew Warfield + */ + +/* + + Things we need to select on in xcs: + + 1. Events arriving on /dev/evtchn + + These will kick a function to read everything off the fd, and scan the + associated control message rings, resulting in notifications sent on + data channels to connected clients. + + 2. New TCP connections on XCS_PORT. + + These will either be control (intially) or associated data connections. + + Control connections will instantiate or rebind to an existing connnection + struct. The control channel is used to configure what events will be + received on an associated data channel. These two channels are split + out because the control channel is synchronous, all messages will return + a result from XCS. The data channel is effectively asynchronous, events + may arrive in the middle of a control message exchange. Additionally, + Having two TCP connections allows the client side to have a blocking + listen loop for data messages, while independently interacting on the + control channel at other places in the code. + + Data connections attach to an existing control struct, using a session + id that is passed during the control connect. There is currently a + one-to-one relationship between data and control channels, but there + could just as easily be many data channels, if there were a set of + clients with identical interests, or if you wanted to trace an existing + client's data traffic. + + 3. Messages arriving on open TCP connections. + There are three types of open connections: + + 3a. Messages arriving on open control channel file descriptors. + + [description of the control protocol here] + + 3b. Messages arriving on open data channel file descriptors. + + [description of the data protocol here] + + 3c. Messages arriving on (new) unbound connections. + + A connection must issue a XCS_CONNECT message to specify what + it is, after which the connection is moved into one of the above + two groups. + + Additionally, we need a periodic timer to do housekeeping. + + 4. Every XCS_GC_INTERVAL seconds, we need to clean up outstanding state. + Specifically, we garbage collect any sessions (connection_t structs) + that have been unconnected for a period of time (XCS_SESSION_TIMEOUT), + and close any connections that have been openned, but not connected + as a control or data connection (XCS_UFD_TIMEOUT). + +*/ + +#include <stdlib.h> +#include <stdio.h> +#include <unistd.h> +#include <sys/time.h> +#include <sys/types.h> +#include <string.h> +#include <signal.h> +#include <sys/socket.h> +#include <netinet/in.h> +#include <arpa/inet.h> +#include <errno.h> +#include <malloc.h> +#include <fcntl.h> +#include "xcs.h" + +#undef fd_max +#define fd_max(x,y) ((x) > (y) ? (x) : (y)) + +/* ------[ Control channel interfaces ]------------------------------------*/ + +static control_channel_t *cc_list[NR_EVENT_CHANNELS]; +static int *dom_port_map = 0; +static int dom_port_map_size = 0; + +static void map_dom_to_port(u32 dom, int port) +{ + if (dom >= dom_port_map_size) { + dom_port_map = (int *)realloc(dom_port_map, + (dom + 10) * sizeof(dom_port_map[0])); + + if (dom_port_map == NULL) { + perror("realloc(dom_port_map)"); + exit(1); + } + + for (; dom_port_map_size < dom + 10; dom_port_map_size++) { + dom_port_map[dom_port_map_size] = -1; + } + } + + dom_port_map[dom] = port; +} + +static int dom_to_port(u32 dom) { + if (dom >= dom_port_map_size) return -1; + + return dom_port_map[dom]; +} + +static void init_interfaces(void) +{ + memset(cc_list, 0, sizeof cc_list); +} + +static control_channel_t *add_interface(u32 dom, int local_port, + int remote_port) +{ + control_channel_t *cc=NULL, *oldcc; + int ret; + + if (cc_list[dom_to_port(dom)] != NULL) + { + return(cc_list[dom_to_port(dom)]); + } + + if (cc_list[local_port] == NULL) + { + cc = ctrl_chan_new(dom, local_port, remote_port); + } + + if (cc == NULL) + return NULL; + + DPRINTF("added a new interface: dom: %u (l:%d,r:%d): %p\n", + dom, local_port, remote_port, cc); + DPRINTF("added a new interface: dom: %u (l:%d,r:%d): %p\n", + dom, cc->local_port, cc->remote_port, cc); + + if ((ret = evtchn_bind(cc->local_port)) != 0) + { + DPRINTF("Got control interface, but couldn't bind evtchan!(%d)\n", ret); + ctrl_chan_free(cc); + return NULL; + } + + if ( cc_list[cc->local_port] != NULL ) + { + oldcc = cc_list[cc->local_port]; + + if ((oldcc->remote_dom != cc->remote_dom) || + (oldcc->remote_port != cc->remote_port)) + { + DPRINTF("CC conflict! (port: %d, old dom: %u, new dom: %u)\n", + cc->local_port, oldcc->remote_dom, cc->remote_dom); + map_dom_to_port(oldcc->remote_dom, -1); + ctrl_chan_free(cc_list[cc->local_port]); + } + } + + cc_list[cc->local_port] = cc; + map_dom_to_port(cc->remote_dom, cc->local_port); + cc->type = CC_TYPE_INTERDOMAIN; + cc->ref_count = 0; + return cc; +} + +control_channel_t *add_virq(int virq) +{ + control_channel_t *cc; + int virq_port; + + if (ctrl_chan_bind_virq(virq, &virq_port) == -1) + return NULL; + + if ((cc_list[virq_port] != NULL) && + (cc_list[virq_port]->type != CC_TYPE_VIRQ)) + return NULL; + + if ((cc_list[virq_port] != NULL) && + (cc_list[virq_port]->type == CC_TYPE_VIRQ)) + return cc_list[virq_port]; + + cc = (control_channel_t *)malloc(sizeof(control_channel_t)); + if ( cc == NULL ) return NULL; + + cc->type = CC_TYPE_VIRQ; + cc->local_port = virq_port; + cc->virq = virq; + + return cc; +} + +void get_interface(control_channel_t *cc) +{ + if (cc != NULL) + cc->ref_count++; +} + +void put_interface(control_channel_t *cc) +{ + if (cc != NULL) + { + cc->ref_count--; + if (cc->ref_count <= 0) + { + DPRINTF("Freeing cc on port %d.\n", cc->local_port); + (void)evtchn_unbind(cc->local_port); + ctrl_chan_free(cc); + } + } +} + +/* ------[ Simple helpers ]------------------------------------------------*/ + +/* listen_socket() is straight from paul sheer's useful select_tut manpage. */ +static int listen_socket (int listen_port) +{ + struct sockaddr_in a; + int s; + int yes; + + if ((s = socket (AF_INET, SOCK_STREAM, 0)) < 0) + { + perror ("socket"); + return -1; + } + + yes = 1; + if (setsockopt(s, SOL_SOCKET, SO_REUSEADDR, + (char *) &yes, sizeof (yes)) < 0) + { + perror ("setsockopt"); + close (s); + return -1; + } + + memset (&a, 0, sizeof (a)); + a.sin_port = htons (listen_port); + a.sin_family = AF_INET; + if (bind(s, (struct sockaddr *) &a, sizeof (a)) < 0) + { + perror ("bind"); + close (s); + return -1; + } + printf ("accepting connections on port %d\n", (int) listen_port); + listen (s, 10); + return s; +} + +/* ------[ Message handlers ]----------------------------------------------*/ + +#define NO_CHANGE 0 +#define CONNECTED 1 +#define DISCONNECTED 2 +int handle_connect_msg( xcs_msg_t *msg, int fd ) +{ + xcs_connect_msg_t *cmsg = &msg->u.connect; + connection_t *con; + int ret = NO_CHANGE; + + switch (msg->type) + { + case XCS_CONNECT_CTRL: + { + if ( cmsg->session_id == 0 ) + { + con = connection_new(); + if ( con == NULL) + { + msg->result = XCS_RSLT_FAILED; + break; + } + msg->result = XCS_RSLT_OK; + cmsg->session_id = con->id; + con->ctrl_fd = fd; + ret = CONNECTED; + DPRINTF("New control connection\n"); + break; + } + + con = get_con_by_session(cmsg->session_id); + if ( con == NULL ) + { + msg->result = XCS_RSLT_BADSESSION; + break; + } + if ( con->ctrl_fd != -1 ) + { + msg->result = XCS_RSLT_CONINUSE; + break; + } + con->ctrl_fd = fd; + msg->result = XCS_RSLT_OK; + ret = CONNECTED; + DPRINTF("Rebound to control connection\n"); + break; + } + case XCS_CONNECT_DATA: + { + con = get_con_by_session(cmsg->session_id); + if ( con == NULL ) + { + msg->result = XCS_RSLT_BADSESSION; + break; + } + if ( con->data_fd != -1 ) + { + msg->result = XCS_RSLT_CONINUSE; + break; + } + con->data_fd = fd; + msg->result = XCS_RSLT_OK; + ret = CONNECTED; + DPRINTF("Attached data connection\n"); + break; + + } + case XCS_CONNECT_BYE: + { + close ( fd ); + ret = DISCONNECTED; + break; + } + } + + return ret; +} + +int handle_control_message( connection_t *con, xcs_msg_t *msg ) +{ + int ret; + int reply_needed = 1; + + DPRINTF("Got message, type %u.\n", msg->type); + + switch (msg->type) + { + case XCS_MSG_BIND: + { + xcs_bind_msg_t *bmsg = &msg->u.bind; + + if ( ! BIND_MSG_VALID(bmsg) ) + { + msg->result = XCS_RSLT_BADREQUEST; + break; + } + + ret = xcs_bind(con, bmsg->port, bmsg->type); + if (ret == 0) { + msg->result = XCS_RSLT_OK; + } else { + msg->result = XCS_RSLT_FAILED; + } + break; + } + case XCS_MSG_UNBIND: + { + xcs_bind_msg_t *bmsg = &msg->u.bind; + + if ( ! BIND_MSG_VALID(bmsg) ) + { + msg->result = XCS_RSLT_BADREQUEST; + break; + } + + ret = xcs_unbind(con, bmsg->port, bmsg->type); + if (ret == 0) { + msg->result = XCS_RSLT_OK; + } else { + msg->result = XCS_RSLT_FAILED; + } + break; + } + case XCS_VIRQ_BIND: + { + control_channel_t *cc; + xcs_virq_msg_t *vmsg = &msg->u.virq; + if ( ! VIRQ_MSG_VALID(vmsg) ) + { + msg->result = XCS_RSLT_BADREQUEST; + break; + } + + cc = add_virq(vmsg->virq); + if (cc == NULL) + { + msg->result = XCS_RSLT_FAILED; + break; + } + ret = xcs_bind(con, cc->local_port, TYPE_VIRQ); + if (ret == 0) { + vmsg->port = cc->local_port; + msg->result = XCS_RSLT_OK; + } else { + msg->result = XCS_RSLT_FAILED; + } + break; + } + + case XCS_CIF_NEW_CC: + { + control_channel_t *cc; + xcs_interface_msg_t *imsg = &msg->u.interface; + + if ( ! INTERFACE_MSG_VALID(imsg) ) + { + msg->result = XCS_RSLT_BADREQUEST; + break; + } + + cc = add_interface(imsg->dom, imsg->local_port, imsg->remote_port); + if (cc != NULL) { + get_interface(cc); + msg->result = XCS_RSLT_OK; + imsg->local_port = cc->local_port; + imsg->remote_port = cc->remote_port; + } else { + msg->result = XCS_RSLT_FAILED; + } + break; + } + + case XCS_CIF_FREE_CC: + { + control_channel_t *cc; + xcs_interface_msg_t *imsg = &msg->u.interface; + + if ( ! INTERFACE_MSG_VALID(imsg) ) + { + msg->result = XCS_RSLT_BADREQUEST; + break; + } + + cc = add_interface(imsg->dom, imsg->local_port, imsg->remote_port); + if (cc != NULL) { + put_interface(cc); + } + msg->result = XCS_RSLT_OK; + break; + } + } + return reply_needed; +} + +void handle_data_message( connection_t *con, xcs_msg_t *msg ) +{ + control_channel_t *cc; + xcs_control_msg_t *cmsg = &msg->u.control; + int port; + + switch (msg->type) + { + case XCS_REQUEST: + if ( cmsg->remote_dom > MAX_DOMS ) + break; + + port = dom_to_port(cmsg->remote_dom); + if (port == -1) break; + cc = cc_list[port]; + if ((cc != NULL) && ( cc->type == CC_TYPE_INTERDOMAIN )) + { + DPRINTF("DN:REQ: dom:%d port: %d type: %d\n", + cc->remote_dom, cc->local_port, + cmsg->msg.type); + ctrl_chan_write_request(cc, cmsg); + ctrl_chan_notify(cc); + } else { + DPRINTF("tried to send a REQ to a null cc\n."); + } + break; + + case XCS_RESPONSE: + if ( cmsg->remote_dom > MAX_DOMS ) + break; + + port = dom_to_port(cmsg->remote_dom); + if (port == -1) break; + cc = cc_list[port]; + if ((cc != NULL) && ( cc->type == CC_TYPE_INTERDOMAIN )) + { + DPRINTF("DN:RSP: dom:%d port: %d type: %d\n", + cc->remote_dom, cc->local_port, + cmsg->msg.type); + ctrl_chan_write_response(cc, cmsg); + ctrl_chan_notify(cc); + } + break; + + case XCS_VIRQ: + if ( !(PORT_VALID(cmsg->local_port)) ) + break; + + cc = cc_list[cmsg->local_port]; + + if ((cc != NULL) && ( cc->type == CC_TYPE_VIRQ )) + { + DPRINTF("DN:VIRQ: virq: %d port: %d\n", + cc->virq, cc->local_port); + ctrl_chan_notify(cc); + } + break; + } +} + +/* ------[ Control interface handler ]-------------------------------------*/ + +/* passed as a function pointer to the lookup. */ +void send_kmsg(connection_t *c, void *arg) +{ + xcs_msg_t *msg = (xcs_msg_t *)arg; + + DPRINTF(" -> CONNECTION %d\n", c->data_fd); + if (c->data_fd > 0) + { + send(c->data_fd, msg, sizeof(xcs_msg_t), 0); + } +} + +int handle_ctrl_if(void) +{ + control_channel_t *cc; + control_msg_t *msg; + xcs_msg_t kmsg; + int chan, ret; + + DPRINTF("Event thread kicked!\n"); +again: + while ((chan = evtchn_read()) > 0) + { + evtchn_unmask(chan); + cc = cc_list[chan]; + if (cc_list[chan] == NULL) { + DPRINTF("event from unknown channel (%d)\n", chan); + continue; + } + + if ( cc_list[chan]->type == CC_TYPE_VIRQ ) + { + DPRINTF("UP:VIRQ: virq:%d port: %d\n", + cc->virq, cc->local_port); + kmsg.type = XCS_VIRQ; + kmsg.u.control.local_port = cc->local_port; + xcs_lookup(cc->local_port, TYPE_VIRQ, send_kmsg, &kmsg); + continue; + } + + while (ctrl_chan_request_to_read(cc)) + { + msg = &kmsg.u.control.msg; + kmsg.type = XCS_REQUEST; + kmsg.u.control.remote_dom = cc->remote_dom; + kmsg.u.control.local_port = cc->local_port; + ret = ctrl_chan_read_request(cc, &kmsg.u.control); + DPRINTF("UP:REQ: dom:%d port: %d type: %d len: %d\n", + cc->remote_dom, cc->local_port, + msg->type, msg->length); + if (ret == 0) + xcs_lookup(cc->local_port, msg->type, send_kmsg, &kmsg); + } + + while (ctrl_chan_response_to_read(cc)) + { + msg = &kmsg.u.control.msg; + kmsg.type = XCS_RESPONSE; + kmsg.u.control.remote_dom = cc->remote_dom; + kmsg.u.control.local_port = cc->local_port; + ret = ctrl_chan_read_response(cc, &kmsg.u.control); + DPRINTF("UP:RSP: dom:%d port: %d type: %d len: %d\n", + cc->remote_dom, cc->local_port, + msg->type, msg->length); + if (ret == 0) + xcs_lookup(cc->local_port, msg->type, send_kmsg, &kmsg); + } + } + + if (chan == -EINTR) + goto again; + + return chan; +} + + +/* ------[ Main xcs code / big select loop ]-------------------------------*/ + + +typedef struct unbound_fd_st { + int fd; + struct timeval born; + struct unbound_fd_st *next; +} unbound_fd_t; + +/* This makes ufd point to the next entry in the list, so need to * + * break/continue if called while iterating. */ +void delete_ufd(unbound_fd_t **ufd) +{ + unbound_fd_t *del_ufd; + + del_ufd = *ufd; + *ufd = (*ufd)->next; + free( del_ufd ); +} + +void gc_ufd_list( unbound_fd_t **ufd ) +{ + struct timeval now, delta; + + gettimeofday(&now, NULL); + + while ( *ufd != NULL ) + { + timersub(&now, &(*ufd)->born, &delta); + if (delta.tv_sec > XCS_UFD_TIMEOUT) + { + DPRINTF("GC-UFD: closing fd: %d\n", (*ufd)->fd); + close((*ufd)->fd); + delete_ufd(ufd); + continue; + } + ufd = &(*ufd)->next; + } +} + +int main (int argc, char*argv[]) +{ + int listen_fd, evtchn_fd; + unbound_fd_t *unbound_fd_list = NULL, **ufd; + struct timeval timeout = { XCS_GC_INTERVAL, 0 }; + connection_t **con; + + /* Initialize xc and event connections. */ + if (ctrl_chan_init() != 0) + { + printf("Couldn't open conneciton to libxc.\n"); + exit(-1); + } + + if ((evtchn_fd = evtchn_open()) < 0) + { + printf("Couldn't open event channel driver interface.\n"); + exit(-1); + } + + /* Initialize control interfaces, bindings. */ + init_interfaces(); + init_bindings(); + + listen_fd = listen_socket(XCS_TCP_PORT); + + /* detach from our controlling tty so that a shell does hang waiting for + stopped jobs. */ + /* we should use getopt() here */ + + if (!(argc == 2 && !strcmp(argv[1], "-i"))) { + pid_t pid = fork(); + int fd; + + if (pid == -1) { + perror("fork()"); + } else if (pid) { + exit(0); + } + + setsid(); + close(2); + close(1); + close(0); + fd = open("/dev/null", O_RDWR); + dup(fd); + dup(fd); + } + + for (;;) + { + int n, ret; + fd_set rd, wr, er; + FD_ZERO ( &rd ); + FD_ZERO ( &wr ); + FD_ZERO ( &er ); + + /* TCP listen fd: */ + FD_SET ( listen_fd, &rd ); + n = fd_max ( n, listen_fd ); + + /* Evtchn fd: */ + FD_SET ( evtchn_fd, &rd ); + n = fd_max ( n, evtchn_fd ); + + /* unbound connection fds: */ + ufd = &unbound_fd_list; + while ((*ufd) != NULL) + { + FD_SET ( (*ufd)->fd, &rd ); + n = fd_max ( n, (*ufd)->fd ); + ufd = &(*ufd)->next; + } + + /* control and data fds: */ + con = &connection_list; + while ((*con) != NULL) + { + if ((*con)->ctrl_fd > 0) + { + FD_SET ( (*con)->ctrl_fd, &rd ); + n = fd_max ( n, (*con)->ctrl_fd ); + } + if ((*con)->data_fd > 0) + { + FD_SET ( (*con)->data_fd, &rd ); + n = fd_max ( n, (*con)->data_fd ); + } + con = &(*con)->next; + } + + ret = select ( n + 1, &rd, &wr, &er, &timeout ); + + if ( (timeout.tv_sec == 0) && (timeout.tv_usec == 0) ) + { + gc_ufd_list(&unbound_fd_list); + gc_connection_list(); + timeout.tv_sec = XCS_GC_INTERVAL; + } + + if ( (ret == -1) && (errno == EINTR) ) + continue; + if ( ret < 0 ) + { + perror ("select()"); + exit(-1); + } + + /* CASE 1: Events arriving on /dev/evtchn. */ + + if ( FD_ISSET (evtchn_fd, &rd )) + handle_ctrl_if(); + + /* CASE 2: New connection on the listen port. */ + if ( FD_ISSET ( listen_fd, &rd )) + { + struct sockaddr_in remote_addr; + int size; + memset (&remote_addr, 0, sizeof (remote_addr)); + size = sizeof remote_addr; + ret = accept(listen_fd, (struct sockaddr *)&remote_addr, &size); + if ( ret < 0 ) + { + perror("accept()"); + } else { + unbound_fd_t *new_ufd; + + new_ufd = (unbound_fd_t *)malloc(sizeof(*new_ufd)); + + if (new_ufd != NULL) + { + gettimeofday(&new_ufd->born, NULL); + new_ufd->fd = ret; + new_ufd->next = unbound_fd_list; + unbound_fd_list = new_ufd; + } else { + perror("malloc unbound connection"); + close(ret); + } + } + } + + /* CASE 3a: Handle messages on control connections. */ + + con = &connection_list; + while ( *con != NULL ) + { + if ( ((*con)->ctrl_fd > 0) && (FD_ISSET((*con)->ctrl_fd, &rd)) ) + { + xcs_msg_t msg; + memset (&msg, 0, sizeof(msg)); + ret = read( (*con)->ctrl_fd, &msg, sizeof(msg) ); + + if ( ret < 0 ) + { + perror("reading ctrl fd."); + } else if ( ret == 0 ) + { + DPRINTF("Control connection dropped.\n"); + close ( (*con)->ctrl_fd ); + (*con)->ctrl_fd = -1; + gettimeofday(&(*con)->disconnect_time, NULL); + } else + { + if ( ret != sizeof(msg) ) + { + DPRINTF("Unexpected frame size!\n"); + continue; + } + + ret = handle_control_message( *con, &msg ); + + if ( ret == 1 ) + send( (*con)->ctrl_fd, &msg, sizeof(msg), 0 ); + } + } + con = &(*con)->next; + } + + /* CASE 3b: Handle messages on data connections. */ + + con = &connection_list; + while ( *con != NULL ) + { + if ( ((*con)->data_fd > 0) && (FD_ISSET((*con)->data_fd, &rd)) ) + { + xcs_msg_t msg; + memset (&msg, 0, sizeof(msg)); + ret = read( (*con)->data_fd, &msg, sizeof(msg) ); + + if ( ret < 0 ) + { + perror("reading data fd."); + } else if ( ret == 0 ) + { + DPRINTF("Data connection dropped.\n"); + close ( (*con)->data_fd ); + (*con)->data_fd = -1; + gettimeofday(&(*con)->disconnect_time, NULL); + } else + { + if ( ret != sizeof(msg) ) + { + DPRINTF("Unexpected frame size!\n"); + continue; + } + + handle_data_message( *con, &msg ); + } + } + con = &(*con)->next; + } + + /* CASE 3c: Handle messages arriving on unbound connections. */ + ufd = &unbound_fd_list; + while ((*ufd) != NULL) + { + if ( FD_ISSET( (*ufd)->fd, &rd ) ) + { + xcs_msg_t msg; + memset (&msg, 0, sizeof(msg)); + ret = read( (*ufd)->fd, &msg, sizeof(msg) ); + + if ( ret == 0 ) + { + close ( (*ufd)->fd ); + delete_ufd(ufd); + continue; /* we just advanced ufd */ + } else { + if ( ret != sizeof(msg) ) + { + DPRINTF("Unexpected frame size!\n"); + continue; + } + + ret = handle_connect_msg( &msg, (*ufd)->fd ); + + if ( (ret == CONNECTED) || (ret == NO_CHANGE) ) + send( (*ufd)->fd, &msg, sizeof(msg), 0 ); + + if ( (ret = CONNECTED) || (ret = DISCONNECTED) ) + { + delete_ufd( ufd ); + continue; + } + } + } + ufd = &(*ufd)->next; + } + } +} + |