/*- * (MPSAFE) * * ng_tty.c * * Copyright (c) 1996-1999 Whistle Communications, Inc. * All rights reserved. * * Subject to the following obligations and disclaimer of warranty, use and * redistribution of this software, in source or object code forms, with or * without modifications are expressly permitted by Whistle Communications; * provided, however, that: * 1. Any and all reproductions of the source or object code must include the * copyright notice above and the following disclaimer of warranties; and * 2. No rights are granted, in any manner or form, to use Whistle * Communications, Inc. trademarks, including the mark "WHISTLE * COMMUNICATIONS" on advertising, endorsements, or otherwise except as * such appears in the above copyright notice or in the software. * * THIS SOFTWARE IS BEING PROVIDED BY WHISTLE COMMUNICATIONS "AS IS", AND * TO THE MAXIMUM EXTENT PERMITTED BY LAW, WHISTLE COMMUNICATIONS MAKES NO * REPRESENTATIONS OR WARRANTIES, EXPRESS OR IMPLIED, REGARDING THIS SOFTWARE, * INCLUDING WITHOUT LIMITATION, ANY AND ALL IMPLIED WARRANTIES OF * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, OR NON-INFRINGEMENT. * WHISTLE COMMUNICATIONS DOES NOT WARRANT, GUARANTEE, OR MAKE ANY * REPRESENTATIONS REGARDING THE USE OF, OR THE RESULTS OF THE USE OF THIS * SOFTWARE IN TERMS OF ITS CORRECTNESS, ACCURACY, RELIABILITY OR OTHERWISE. * IN NO EVENT SHALL WHISTLE COMMUNICATIONS BE LIABLE FOR ANY DAMAGES * RESULTING FROM OR ARISING OUT OF ANY USE OF THIS SOFTWARE, INCLUDING * WITHOUT LIMITATION, ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, * PUNITIVE, OR CONSEQUENTIAL DAMAGES, PROCUREMENT OF SUBSTITUTE GOODS OR * SERVICES, LOSS OF USE, DATA OR PROFITS, HOWEVER CAUSED AND UNDER ANY * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF * THIS SOFTWARE, EVEN IF WHISTLE COMMUNICATIONS IS ADVISED OF THE POSSIBILITY * OF SUCH DAMAGE. * * Author: Archie Cobbs * * $FreeBSD: src/sys/netgraph/ng_tty.c,v 1.37 2006/11/06 13:42:03 rwatson Exp $ * $Whistle: ng_tty.c,v 1.21 1999/11/01 09:24:52 julian Exp $ */ /* * This file implements a terminal line discipline that is also a * netgraph node. Installing this line discipline on a terminal device * instantiates a new netgraph node of this type, which allows access * to the device via the "hook" hook of the node. * * Once the line discipline is installed, you can find out the name * of the corresponding netgraph node via a NGIOCGINFO ioctl(). * * Incoming characters are delievered to the hook one at a time, each * in its own mbuf. You may optionally define a ``hotchar,'' which causes * incoming characters to be buffered up until either the hotchar is * seen or the mbuf is full (MHLEN bytes). Then all buffered characters * are immediately delivered. */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include "ng_tty.h" /* Misc defs */ #define MAX_MBUFQ 3 /* Max number of queued mbufs */ #define NGT_HIWATER 400 /* High water mark on output */ /* Per-node private info */ struct ngt_sc { struct tty *tp; /* Terminal device */ node_p node; /* Netgraph node */ hook_p hook; /* Netgraph hook */ struct ifqueue outq; /* Queue of outgoing data */ struct mbuf *m; /* Incoming data buffer */ short hotchar; /* Hotchar, or -1 if none */ u_int flags; /* Flags */ struct callout chand; /* See man timeout(9) */ }; typedef struct ngt_sc *sc_p; /* Flags */ #define FLG_DEBUG 0x0002 #define FLG_DIE 0x0004 /* Line discipline methods */ static int ngt_open(struct cdev *dev, struct tty *tp); static int ngt_close(struct tty *tp, int flag); static int ngt_read(struct tty *tp, struct uio *uio, int flag); static int ngt_write(struct tty *tp, struct uio *uio, int flag); static int ngt_tioctl(struct tty *tp, u_long cmd, caddr_t data, int flag, struct ucred *cred); static int ngt_input(int c, struct tty *tp); static int ngt_start(struct tty *tp); /* Netgraph methods */ static ng_constructor_t ngt_constructor; static ng_rcvmsg_t ngt_rcvmsg; static ng_shutdown_t ngt_shutdown; static ng_newhook_t ngt_newhook; static ng_connect_t ngt_connect; static ng_rcvdata_t ngt_rcvdata; static ng_disconnect_t ngt_disconnect; static int ngt_mod_event(module_t mod, int event, void *data); /* Other stuff */ static void ngt_timeout(node_p node, hook_p hook, void *arg1, int arg2); #define ERROUT(x) do { error = (x); goto done; } while (0) /* Line discipline descriptor */ static struct linesw ngt_disc = { .l_open = ngt_open, .l_close = ngt_close, .l_read = ngt_read, .l_write = ngt_write, .l_ioctl = ngt_tioctl, .l_rint = ngt_input, .l_start = ngt_start, .l_modem = ttymodem, }; /* Netgraph node type descriptor */ static struct ng_type typestruct = { .version = NG_ABI_VERSION, .name = NG_TTY_NODE_TYPE, .mod_event = ngt_mod_event, .constructor = ngt_constructor, .rcvmsg = ngt_rcvmsg, .shutdown = ngt_shutdown, .newhook = ngt_newhook, .connect = ngt_connect, .rcvdata = ngt_rcvdata, .disconnect = ngt_disconnect, }; NETGRAPH_INIT(tty, &typestruct); /* * Locking: * * - node private data and tp->t_lsc is protected by mutex in struct * ifqueue, locking is done using IF_XXX() macros. * - in all tty methods we should acquire node ifqueue mutex, when accessing * private data. * - in _rcvdata() we should use locked versions of IF_{EN,DE}QUEUE() since * we may have multiple _rcvdata() threads. * - when calling any of tty methods from netgraph methods, we should * acquire tty locking (now Giant). * * - ngt_unit is incremented atomically. */ static int ngt_unit; static int ngt_ldisc; /****************************************************************** LINE DISCIPLINE METHODS ******************************************************************/ /* * Set our line discipline on the tty. * Called from device open routine or ttioctl() */ static int ngt_open(struct cdev *dev, struct tty *tp) { char name[sizeof(NG_TTY_NODE_TYPE) + 8]; sc_p sc; int error; /* Super-user only */ error = caps_priv_check_self(SYSCAP_NONET_NETGRAPH); if (error) return (error); /* Initialize private struct */ sc = kmalloc(sizeof(*sc), M_NETGRAPH, M_WAITOK | M_ZERO); lwkt_gettoken(&tp->t_token); sc->tp = tp; sc->hotchar = NG_TTY_DFL_HOTCHAR; sc->outq.ifq_maxlen = MAX_MBUFQ; /* Setup netgraph node */ error = ng_make_node_common(&typestruct, &sc->node); if (error) { kfree(sc, M_NETGRAPH); lwkt_reltoken(&tp->t_token); return (error); } atomic_add_int(&ngt_unit, 1); ksnprintf(name, sizeof(name), "%s%d", typestruct.name, ngt_unit); /* Assign node its name */ if ((error = ng_name_node(sc->node, name))) { sc->flags |= FLG_DIE; NG_NODE_UNREF(sc->node); log(LOG_ERR, "%s: node name exists?\n", name); lwkt_reltoken(&tp->t_token); return (error); } /* Set back pointers */ NG_NODE_SET_PRIVATE(sc->node, sc); tp->t_sc = sc; callout_init_mp(&sc->chand); /* * Pre-allocate cblocks to the an appropriate amount. * I'm not sure what is appropriate. */ ttyflush(tp, FREAD | FWRITE); clist_alloc_cblocks(&tp->t_canq, 0); clist_alloc_cblocks(&tp->t_rawq, 0); clist_alloc_cblocks(&tp->t_outq, MLEN + NGT_HIWATER); lwkt_reltoken(&tp->t_token); return (error); } /* * Line specific close routine, called from device close routine * and from ttioctl. This causes the node to be destroyed as well. */ static int ngt_close(struct tty *tp, int flag) { const sc_p sc = (sc_p) tp->t_sc; lwkt_gettoken(&tp->t_token); ttyflush(tp, FREAD | FWRITE); clist_free_cblocks(&tp->t_outq); if (sc != NULL) { if (callout_pending(&sc->chand)) ng_uncallout(&sc->chand, sc->node); tp->t_sc = NULL; sc->flags |= FLG_DIE; ng_rmnode_self(sc->node); } lwkt_reltoken(&tp->t_token); return (0); } /* * Once the device has been turned into a node, we don't allow reading. */ static int ngt_read(struct tty *tp, struct uio *uio, int flag) { return (EIO); } /* * Once the device has been turned into a node, we don't allow writing. */ static int ngt_write(struct tty *tp, struct uio *uio, int flag) { return (EIO); } /* * We implement the NGIOCGINFO ioctl() defined in ng_message.h. */ static int ngt_tioctl(struct tty *tp, u_long cmd, caddr_t data, int flag, struct ucred *cred) { const sc_p sc = (sc_p) tp->t_sc; if (sc == NULL) { /* No node attached */ return (0); } lwkt_gettoken(&tp->t_token); switch (cmd) { case NGIOCGINFO: { struct nodeinfo *const ni = (struct nodeinfo *) data; const node_p node = sc->node; bzero(ni, sizeof(*ni)); if (NG_NODE_HAS_NAME(node)) strncpy(ni->name, NG_NODE_NAME(node), sizeof(ni->name) - 1); strncpy(ni->type, node->nd_type->name, sizeof(ni->type) - 1); ni->id = (u_int32_t) ng_node2ID(node); ni->hooks = NG_NODE_NUMHOOKS(node); break; } default: lwkt_reltoken(&tp->t_token); return (ENOIOCTL); } lwkt_reltoken(&tp->t_token); return (0); } /* * Receive data coming from the device. We get one character at * a time, which is kindof silly. * * Full locking of softc is not required, since we are the only * user of sc->m. */ static int ngt_input(int c, struct tty *tp) { sc_p sc; node_p node; struct mbuf *m; int error = 0; lwkt_gettoken(&tp->t_token); sc = (sc_p) tp->t_sc; if (sc == NULL) { /* No node attached */ lwkt_reltoken(&tp->t_token); return (0); } node = sc->node; if (tp != sc->tp) panic("ngt_input"); /* Check for error conditions */ if ((tp->t_state & TS_CONNECTED) == 0) { if (sc->flags & FLG_DEBUG) log(LOG_DEBUG, "%s: no carrier\n", NG_NODE_NAME(node)); lwkt_reltoken(&tp->t_token); return (0); } if (c & TTY_ERRORMASK) { /* framing error or overrun on this char */ if (sc->flags & FLG_DEBUG) log(LOG_DEBUG, "%s: line error %x\n", NG_NODE_NAME(node), c & TTY_ERRORMASK); lwkt_reltoken(&tp->t_token); return (0); } c &= TTY_CHARMASK; /* Get a new header mbuf if we need one */ if (!(m = sc->m)) { MGETHDR(m, M_NOWAIT, MT_DATA); if (!m) { if (sc->flags & FLG_DEBUG) log(LOG_ERR, "%s: can't get mbuf\n", NG_NODE_NAME(node)); lwkt_reltoken(&tp->t_token); return (ENOBUFS); } m->m_len = m->m_pkthdr.len = 0; m->m_pkthdr.rcvif = NULL; sc->m = m; } /* Add char to mbuf */ *mtod(m, u_char *) = c; m->m_data++; m->m_len++; m->m_pkthdr.len++; /* Ship off mbuf if it's time */ if (sc->hotchar == -1 || c == sc->hotchar || m->m_len >= MHLEN) { m->m_data = m->m_pktdat; sc->m = NULL; /* * We have built our mbuf without checking that we actually * have a hook to send it. This was done to avoid * acquiring mutex on each character. Check now. * */ if (sc->hook == NULL) { m_freem(m); lwkt_reltoken(&tp->t_token); return (0); /* XXX: original behavior */ } NG_SEND_DATA_ONLY(error, sc->hook, m); /* Will queue */ } lwkt_reltoken(&tp->t_token); return (error); } /* * This is called when the device driver is ready for more output. * Also called from ngt_rcv_data() when a new mbuf is available for output. */ static int ngt_start(struct tty *tp) { const sc_p sc = (sc_p) tp->t_sc; lwkt_gettoken(&tp->t_token); while (tp->t_outq.c_cc < NGT_HIWATER) { /* XXX 2.2 specific ? */ struct mbuf *m; /* Remove first mbuf from queue */ IF_DEQUEUE(&sc->outq, m); if (m == NULL) break; /* Send as much of it as possible */ while (m != NULL) { int sent; sent = m->m_len - clist_btoq(mtod(m, u_char *), m->m_len, &tp->t_outq); m->m_data += sent; m->m_len -= sent; if (m->m_len > 0) break; /* device can't take no more */ m = m_free(m); } /* Put remainder of mbuf chain (if any) back on queue */ if (m != NULL) { IF_PREPEND(&sc->outq, m); break; } } /* Call output process whether or not there is any output. We are * being called in lieu of ttstart and must do what it would. */ if (tp->t_oproc != NULL) (*tp->t_oproc) (tp); /* This timeout is needed for operation on a pseudo-tty, because the * pty code doesn't call pppstart after it has drained the t_outq. */ /* XXX: outq not locked */ if (!IF_QEMPTY(&sc->outq) && !callout_pending(&sc->chand)) ng_callout(&sc->chand, sc->node, NULL, 1, ngt_timeout, NULL, 0); lwkt_reltoken(&tp->t_token); return (0); } /* * We still have data to output to the device, so try sending more. */ static void ngt_timeout(node_p node, hook_p hook, void *arg1, int arg2) { const sc_p sc = NG_NODE_PRIVATE(node); struct tty *tp = sc->tp; lwkt_gettoken(&tp->t_token); ngt_start(sc->tp); lwkt_reltoken(&tp->t_token); } /****************************************************************** NETGRAPH NODE METHODS ******************************************************************/ /* * Initialize a new node of this type. * * We only allow nodes to be created as a result of setting * the line discipline on a tty, so always return an error if not. */ static int ngt_constructor(node_p node) { return (EOPNOTSUPP); } /* * Add a new hook. There can only be one. */ static int ngt_newhook(node_p node, hook_p hook, const char *name) { const sc_p sc = NG_NODE_PRIVATE(node); struct tty *tp = sc->tp; if (strcmp(name, NG_TTY_HOOK)) return (EINVAL); lwkt_gettoken(&tp->t_token); if (sc->hook) { lwkt_reltoken(&tp->t_token); return (EISCONN); } sc->hook = hook; lwkt_reltoken(&tp->t_token); return (0); } /* * Set the hook into queueing mode (for outgoing packets), * so that we wont deliver mbuf thru the whole graph holding * tty locks. */ static int ngt_connect(hook_p hook) { NG_HOOK_FORCE_QUEUE(NG_HOOK_PEER(hook)); /* * XXX: While ngt_start() is Giant-locked, queue incoming * packets, too. Otherwise we acquire Giant holding some * IP stack locks, e.g. divinp, and this makes WITNESS scream. */ NG_HOOK_FORCE_QUEUE(hook); return (0); } /* * Disconnect the hook */ static int ngt_disconnect(hook_p hook) { const sc_p sc = NG_NODE_PRIVATE(NG_HOOK_NODE(hook)); struct tty *tp = sc->tp; lwkt_gettoken(&tp->t_token); if (hook != sc->hook) panic(__func__); sc->hook = NULL; lwkt_reltoken(&tp->t_token); return (0); } /* * Remove this node. The does the netgraph portion of the shutdown. * This should only be called indirectly from ngt_close(). * * tp->t_lsc is already NULL, so we should be protected from * tty calls now. */ static int ngt_shutdown(node_p node) { const sc_p sc = NG_NODE_PRIVATE(node); struct tty *tp = sc->tp; lwkt_gettoken(&tp->t_token); if (!(sc->flags & FLG_DIE)) { lwkt_reltoken(&tp->t_token); return (EOPNOTSUPP); } /* Free resources */ IF_DRAIN(&sc->outq); m_freem(sc->m); kfree(sc, M_NETGRAPH); lwkt_reltoken(&tp->t_token); return (0); } /* * Receive incoming data from netgraph system. Put it on our * output queue and start output if necessary. */ static int ngt_rcvdata(hook_p hook, item_p item) { const sc_p sc = NG_NODE_PRIVATE(NG_HOOK_NODE(hook)); struct tty *tp = sc->tp; struct mbuf *m; int qlen; if (hook != sc->hook) panic(__func__); NGI_GET_M(item, m); NG_FREE_ITEM(item); if (IF_QFULL(&sc->outq)) { IF_DROP(&sc->outq); NG_FREE_M(m); return (ENOBUFS); } IF_ENQUEUE(&sc->outq, m); qlen = sc->outq.ifq_len; /* * If qlen > 1, then we should already have a scheduled callout. */ if (qlen == 1) { lwkt_gettoken(&tp->t_token); ngt_start(sc->tp); lwkt_reltoken(&tp->t_token); } return (0); } /* * Receive control message */ static int ngt_rcvmsg(node_p node, item_p item, hook_p lasthook) { const sc_p sc = NG_NODE_PRIVATE(node); struct ng_mesg *msg, *resp = NULL; int error = 0; NGI_GET_MSG(item, msg); switch (msg->header.typecookie) { case NGM_TTY_COOKIE: switch (msg->header.cmd) { case NGM_TTY_SET_HOTCHAR: { int hotchar; if (msg->header.arglen != sizeof(int)) ERROUT(EINVAL); hotchar = *((int *) msg->data); if (hotchar != (u_char) hotchar && hotchar != -1) ERROUT(EINVAL); sc->hotchar = hotchar; /* race condition is OK */ break; } case NGM_TTY_GET_HOTCHAR: NG_MKRESPONSE(resp, msg, sizeof(int), M_WAITOK | M_NULLOK); if (!resp) ERROUT(ENOMEM); /* Race condition here is OK */ *((int *) resp->data) = sc->hotchar; break; default: ERROUT(EINVAL); } break; default: ERROUT(EINVAL); } done: NG_RESPOND_MSG(error, node, item, resp); NG_FREE_MSG(msg); return (error); } /****************************************************************** INITIALIZATION ******************************************************************/ /* * Handle loading and unloading for this node type */ static int ngt_mod_event(module_t mod, int event, void *data) { int error = 0; switch (event) { case MOD_LOAD: /* Register line discipline */ if ((ngt_ldisc = ldisc_register(NETGRAPHDISC, &ngt_disc)) < 0) { log(LOG_ERR, "%s: can't register line discipline", __func__); return (EIO); } break; case MOD_UNLOAD: /* Unregister line discipline */ ldisc_deregister(ngt_ldisc); break; default: error = EOPNOTSUPP; break; } return (error); }