uxnet.c

putty

	    memcpy(buf, sin6->sin6_addr.s6_addr + 12, 4);
	    PUT_16BIT_MSB_FIRST(buf+4, ntohs(sin6->sin6_port));
	} else
	    /* This is stupid, but it's what XLib does. */
	    memset(buf, 0, 6);
	break;
#endif
      case AF_UNIX:
	*lenp = 6;
	buf = snewn(*lenp, char);
	PUT_32BIT_MSB_FIRST(buf, unix_addr--);
        PUT_16BIT_MSB_FIRST(buf+4, getpid());
	break;

	/* XXX IPV6 */

      default:
	return NULL;
    }

    return buf;
}

/*
 * The function which tries to send on a socket once it's deemed
 * writable.
 */
void try_send(Actual_Socket s)
{
    while (s->sending_oob || bufchain_size(&s->output_data) > 0) {
	int nsent;
	int err;
	void *data;
	int len, urgentflag;

	if (s->sending_oob) {
	    urgentflag = MSG_OOB;
	    len = s->sending_oob;
	    data = &s->oobdata;
	} else {
	    urgentflag = 0;
	    bufchain_prefix(&s->output_data, &data, &len);
	}
	nsent = send(s->s, data, len, urgentflag);
	noise_ultralight(nsent);
	if (nsent <= 0) {
	    err = (nsent < 0 ? errno : 0);
	    if (err == EWOULDBLOCK) {
		/*
		 * Perfectly normal: we've sent all we can for the moment.
		 */
		s->writable = FALSE;
		return;
	    } else {
		/*
		 * We unfortunately can't just call plug_closing(),
		 * because it's quite likely that we're currently
		 * _in_ a call from the code we'd be calling back
		 * to, so we'd have to make half the SSH code
		 * reentrant. Instead we flag a pending error on
		 * the socket, to be dealt with (by calling
		 * plug_closing()) at some suitable future moment.
		 */
		s->pending_error = err;
		return;
	    }
	} else {
	    if (s->sending_oob) {
		if (nsent < len) {
		    memmove(s->oobdata, s->oobdata+nsent, len-nsent);
		    s->sending_oob = len - nsent;
		} else {
		    s->sending_oob = 0;
		}
	    } else {
		bufchain_consume(&s->output_data, nsent);
	    }
	}
    }
    uxsel_tell(s);
}

static int sk_tcp_write(Socket sock, const char *buf, int len)
{
    Actual_Socket s = (Actual_Socket) sock;

    /*
     * Add the data to the buffer list on the socket.
     */
    bufchain_add(&s->output_data, buf, len);

    /*
     * Now try sending from the start of the buffer list.
     */
    if (s->writable)
	try_send(s);

    /*
     * Update the select() status to correctly reflect whether or
     * not we should be selecting for write.
     */
    uxsel_tell(s);

    return bufchain_size(&s->output_data);
}

static int sk_tcp_write_oob(Socket sock, const char *buf, int len)
{
    Actual_Socket s = (Actual_Socket) sock;

    /*
     * Replace the buffer list on the socket with the data.
     */
    bufchain_clear(&s->output_data);
    assert(len <= sizeof(s->oobdata));
    memcpy(s->oobdata, buf, len);
    s->sending_oob = len;

    /*
     * Now try sending from the start of the buffer list.
     */
    if (s->writable)
	try_send(s);

    /*
     * Update the select() status to correctly reflect whether or
     * not we should be selecting for write.
     */
    uxsel_tell(s);

    return s->sending_oob;
}

static int net_select_result(int fd, int event)
{
    int ret;
    char buf[20480];		       /* nice big buffer for plenty of speed */
    Actual_Socket s;
    u_long atmark;

    /* Find the Socket structure */
    s = find234(sktree, &fd, cmpforsearch);
    if (!s)
	return 1;		       /* boggle */

    noise_ultralight(event);

    switch (event) {
      case 4:			       /* exceptional */
	if (!s->oobinline) {
	    /*
	     * On a non-oobinline socket, this indicates that we
	     * can immediately perform an OOB read and get back OOB
	     * data, which we will send to the back end with
	     * type==2 (urgent data).
	     */
	    ret = recv(s->s, buf, sizeof(buf), MSG_OOB);
	    noise_ultralight(ret);
	    if (ret <= 0) {
                return plug_closing(s->plug,
				    ret == 0 ? "Internal networking trouble" :
				    strerror(errno), errno, 0);
	    } else {
                /*
                 * Receiving actual data on a socket means we can
                 * stop falling back through the candidate
                 * addresses to connect to.
                 */
                if (s->addr) {
                    sk_addr_free(s->addr);
                    s->addr = NULL;
                }
		return plug_receive(s->plug, 2, buf, ret);
	    }
	    break;
	}

	/*
	 * If we reach here, this is an oobinline socket, which
	 * means we should set s->oobpending and then deal with it
	 * when we get called for the readability event (which
	 * should also occur).
	 */
	s->oobpending = TRUE;
        break;
      case 1: 			       /* readable; also acceptance */
	if (s->listener) {
	    /*
	     * On a listening socket, the readability event means a
	     * connection is ready to be accepted.
	     */
#ifdef NO_IPV6
	    struct sockaddr_in ss;
#else
	    struct sockaddr_storage ss;
#endif
	    socklen_t addrlen = sizeof(ss);
	    int t;  /* socket of connection */

	    memset(&ss, 0, addrlen);
	    t = accept(s->s, (struct sockaddr *)&ss, &addrlen);
	    if (t < 0) {
		break;
	    }

	    if (s->localhost_only &&
		!sockaddr_is_loopback((struct sockaddr *)&ss)) {
		close(t);	       /* someone let nonlocal through?! */
	    } else if (plug_accepting(s->plug, t)) {
		close(t);	       /* denied or error */
	    }
	    break;
	}

	/*
	 * If we reach here, this is not a listening socket, so
	 * readability really means readability.
	 */

	/* In the case the socket is still frozen, we don't even bother */
	if (s->frozen) {
	    s->frozen_readable = 1;
	    break;
	}

	/*
	 * We have received data on the socket. For an oobinline
	 * socket, this might be data _before_ an urgent pointer,
	 * in which case we send it to the back end with type==1
	 * (data prior to urgent).
	 */
	if (s->oobinline && s->oobpending) {
	    atmark = 1;
	    if (ioctl(s->s, SIOCATMARK, &atmark) == 0 && atmark)
		s->oobpending = FALSE; /* clear this indicator */
	} else
	    atmark = 1;

	ret = recv(s->s, buf, s->oobpending ? 1 : sizeof(buf), 0);
	noise_ultralight(ret);
	if (ret < 0) {
	    if (errno == EWOULDBLOCK) {
		break;
	    }
	}
	if (ret < 0) {
            /*
             * An error at this point _might_ be an error reported
             * by a non-blocking connect(). So before we return a
             * panic status to the user, let's just see whether
             * that's the case.
             */
            int err = errno;
	    if (s->addr) {
		plug_log(s->plug, 1, s->addr, s->port, strerror(err), err);
		while (s->addr && sk_nextaddr(s->addr)) {
		    err = try_connect(s);
		}
	    }
            if (err != 0)
                return plug_closing(s->plug, strerror(err), err, 0);
	} else if (0 == ret) {
	    return plug_closing(s->plug, NULL, 0, 0);
	} else {
            /*
             * Receiving actual data on a socket means we can
             * stop falling back through the candidate
             * addresses to connect to.
             */
            if (s->addr) {
                sk_addr_free(s->addr);
                s->addr = NULL;
            }
	    return plug_receive(s->plug, atmark ? 0 : 1, buf, ret);
	}
	break;
      case 2:			       /* writable */
	if (!s->connected) {
	    /*
	     * select() reports a socket as _writable_ when an
	     * asynchronous connection is completed.
	     */
	    s->connected = s->writable = 1;
	    uxsel_tell(s);
	    break;
	} else {
	    int bufsize_before, bufsize_after;
	    s->writable = 1;
	    bufsize_before = s->sending_oob + bufchain_size(&s->output_data);
	    try_send(s);
	    bufsize_after = s->sending_oob + bufchain_size(&s->output_data);
	    if (bufsize_after < bufsize_before)
		plug_sent(s->plug, bufsize_after);
	}
	break;
    }

    return 1;
}

/*
 * Deal with socket errors detected in try_send().
 */
void net_pending_errors(void)
{
    int i;
    Actual_Socket s;

    /*
     * This might be a fiddly business, because it's just possible
     * that handling a pending error on one socket might cause
     * others to be closed. (I can't think of any reason this might
     * happen in current SSH implementation, but to maintain
     * generality of this network layer I'll assume the worst.)
     * 
     * So what we'll do is search the socket list for _one_ socket
     * with a pending error, and then handle it, and then search
     * the list again _from the beginning_. Repeat until we make a
     * pass with no socket errors present. That way we are
     * protected against the socket list changing under our feet.
     */

    do {
	for (i = 0; (s = index234(sktree, i)) != NULL; i++) {
	    if (s->pending_error) {
		/*
		 * An error has occurred on this socket. Pass it to the
		 * plug.
		 */
		plug_closing(s->plug, strerror(s->pending_error),
			     s->pending_error, 0);
		break;
	    }
	}
    } while (s);
}

/*
 * Each socket abstraction contains a `void *' private field in
 * which the client can keep state.
 */
static void sk_tcp_set_private_ptr(Socket sock, void *ptr)
{
    Actual_Socket s = (Actual_Socket) sock;
    s->private_ptr = ptr;
}

static void *sk_tcp_get_private_ptr(Socket sock)
{
    Actual_Socket s = (Actual_Socket) sock;
    return s->private_ptr;
}

/*
 * Special error values are returned from sk_namelookup and sk_new
 * if there's a problem. These functions extract an error message,
 * or return NULL if there's no problem.
 */
const char *sk_addr_error(SockAddr addr)
{
    return addr->error;
}
static const char *sk_tcp_socket_error(Socket sock)
{
    Actual_Socket s = (Actual_Socket) sock;
    return s->error;
}

static void sk_tcp_set_frozen(Socket sock, int is_frozen)
{
    Actual_Socket s = (Actual_Socket) sock;
    if (s->frozen == is_frozen)
	return;
    s->frozen = is_frozen;
    if (!is_frozen && s->frozen_readable) {
	char c;
	recv(s->s, &c, 1, MSG_PEEK);
    }
    s->frozen_readable = 0;
    uxsel_tell(s);
}

static void uxsel_tell(Actual_Socket s)
{
    int rwx = 0;
    if (s->listener) {
	rwx |= 1;			/* read == accept */
    } else {
	if (!s->connected)
	    rwx |= 2;			/* write == connect */
	if (s->connected && !s->frozen)
	    rwx |= 1 | 4;		/* read, except */
	if (bufchain_size(&s->output_data))
	    rwx |= 2;			/* write */
    }
    uxsel_set(s->s, rwx, net_select_result);
}

int net_service_lookup(char *service)
{
    struct servent *se;
    se = getservbyname(service, NULL);
    if (se != NULL)
	return ntohs(se->s_port);
    else
	return 0;
}

SockAddr platform_get_x11_unix_address(int displaynum, char **canonicalname)
{
    SockAddr ret = snew(struct SockAddr_tag);
    int n;

    memset(ret, 0, sizeof *ret);
    ret->family = AF_UNIX;
    n = snprintf(ret->hostname, sizeof ret->hostname,
		 "%s%d", X11_UNIX_PATH, displaynum);
    if(n < 0)
	ret->error = "snprintf failed";
    else if(n >= sizeof ret->hostname)
	ret->error = "X11 UNIX name too long";
    else
	*canonicalname = dupstr(ret->hostname);
#ifndef NO_IPV6
    ret->ai = ret->ais = NULL;
#else
    ret->addresses = NULL;
    ret->curraddr = ret->naddresses = 0;
#endif
    return ret;
}