/* Sets conn->state to READING when done. */
static krb5_boolean
service_tcp_write(krb5_context context, const krb5_data *realm,
struct conn_state *conn, struct select_state *selstate)
{
ssize_t nwritten;
SOCKET_WRITEV_TEMP tmp;
TRACE_SENDTO_KDC_TCP_SEND(context, &conn->addr);
nwritten = SOCKET_WRITEV(conn->fd, conn->out.sgp, conn->out.sg_count, tmp);
if (nwritten < 0) {
TRACE_SENDTO_KDC_TCP_ERROR_SEND(context, &conn->addr, SOCKET_ERRNO);
kill_conn(context, conn, selstate);
return FALSE;
}
while (nwritten) {
sg_buf *sgp = conn->out.sgp;
if ((size_t)nwritten < SG_LEN(sgp)) {
SG_ADVANCE(sgp, (size_t)nwritten);
nwritten = 0;
} else {
nwritten -= SG_LEN(sgp);
conn->out.sgp++;
conn->out.sg_count--;
}
}
if (conn->out.sg_count == 0) {
/* Done writing, switch to reading. */
cm_read(selstate, conn->fd);
conn->state = READING;
}
return FALSE;
}
static int
service_tcp_fd(krb5_context context, struct conn_state *conn,
struct select_state *selstate, int ssflags)
{
int e = 0;
ssize_t nwritten, nread;
if (!(ssflags & (SSF_READ|SSF_WRITE|SSF_EXCEPTION)))
abort();
switch (conn->state) {
SOCKET_WRITEV_TEMP tmp;
case CONNECTING:
if (ssflags & SSF_READ) {
/* Bad -- the KDC shouldn't be sending to us first. */
e = EINVAL /* ?? */;
kill_conn:
TRACE_SENDTO_KDC_TCP_DISCONNECT(context, conn);
kill_conn(conn, selstate, e);
if (e == EINVAL) {
closesocket(conn->fd);
conn->fd = INVALID_SOCKET;
}
return e == 0;
}
if (ssflags & SSF_EXCEPTION) {
handle_exception:
e = get_so_error(conn->fd);
if (e)
dprint("socket error on exception fd: %m", e);
else
dprint("no socket error info available on exception fd");
goto kill_conn;
}
/*
* Connect finished -- but did it succeed or fail?
* UNIX sets can_write if failed.
* Call getsockopt to see if error pending.
*
* (For most UNIX systems it works to just try writing the
* first time and detect an error. But Bill Dodd at IBM
* reports that some version of AIX, SIGPIPE can result.)
*/
e = get_so_error(conn->fd);
if (e) {
TRACE_SENDTO_KDC_TCP_ERROR_CONNECT(context, conn, e);
dprint("socket error on write fd: %m", e);
goto kill_conn;
}
conn->state = WRITING;
goto try_writing;
case WRITING:
if (ssflags & SSF_READ) {
e = E2BIG;
/* Bad -- the KDC shouldn't be sending anything yet. */
goto kill_conn;
}
if (ssflags & SSF_EXCEPTION)
goto handle_exception;
try_writing:
dprint("trying to writev %d (%d bytes) to fd %d\n",
conn->x.out.sg_count,
((conn->x.out.sg_count == 2 ? SG_LEN(&conn->x.out.sgp[1]) : 0)
+ SG_LEN(&conn->x.out.sgp[0])),
conn->fd);
TRACE_SENDTO_KDC_TCP_SEND(context, conn);
nwritten = SOCKET_WRITEV(conn->fd, conn->x.out.sgp,
conn->x.out.sg_count, tmp);
if (nwritten < 0) {
e = SOCKET_ERRNO;
TRACE_SENDTO_KDC_TCP_ERROR_SEND(context, conn, e);
dprint("failed: %m\n", e);
goto kill_conn;
}
dprint("wrote %d bytes\n", nwritten);
while (nwritten) {
sg_buf *sgp = conn->x.out.sgp;
if ((size_t) nwritten < SG_LEN(sgp)) {
SG_ADVANCE(sgp, (size_t) nwritten);
nwritten = 0;
} else {
nwritten -= SG_LEN(sgp);
conn->x.out.sgp++;
conn->x.out.sg_count--;
if (conn->x.out.sg_count == 0 && nwritten != 0)
/* Wrote more than we wanted to? */
abort();
}
}
if (conn->x.out.sg_count == 0) {
/* Done writing, switch to reading. */
/* Don't call shutdown at this point because
* some implementations cannot deal with half-closed connections.*/
FD_CLR(conn->fd, &selstate->wfds);
/* Q: How do we detect failures to send the remaining data
to the remote side, since we're in non-blocking mode?
Will we always get errors on the reading side? */
dprint("switching fd %d to READING\n", conn->fd);
conn->state = READING;
conn->x.in.bufsizebytes_read = 0;
conn->x.in.bufsize = 0;
conn->x.in.buf = 0;
conn->x.in.pos = 0;
conn->x.in.n_left = 0;
}
return 0;
case READING:
if (ssflags & SSF_EXCEPTION) {
if (conn->x.in.buf) {
free(conn->x.in.buf);
conn->x.in.buf = 0;
}
goto handle_exception;
}
if (conn->x.in.bufsizebytes_read == 4) {
/* Reading data. */
dprint("reading %d bytes of data from fd %d\n",
(int) conn->x.in.n_left, conn->fd);
nread = SOCKET_READ(conn->fd, conn->x.in.pos, conn->x.in.n_left);
if (nread <= 0) {
e = nread ? SOCKET_ERRNO : ECONNRESET;
free(conn->x.in.buf);
conn->x.in.buf = 0;
TRACE_SENDTO_KDC_TCP_ERROR_RECV(context, conn, e);
goto kill_conn;
}
conn->x.in.n_left -= nread;
conn->x.in.pos += nread;
if (conn->x.in.n_left <= 0) {
/* We win! */
return 1;
}
} else {
/* Reading length. */
nread = SOCKET_READ(conn->fd,
conn->x.in.bufsizebytes + conn->x.in.bufsizebytes_read,
4 - conn->x.in.bufsizebytes_read);
if (nread < 0) {
TRACE_SENDTO_KDC_TCP_ERROR_RECV_LEN(context, conn, e);
e = SOCKET_ERRNO;
goto kill_conn;
}
conn->x.in.bufsizebytes_read += nread;
if (conn->x.in.bufsizebytes_read == 4) {
unsigned long len = load_32_be (conn->x.in.bufsizebytes);
dprint("received length on fd %d is %d\n", conn->fd, (int)len);
/* Arbitrary 1M cap. */
if (len > 1 * 1024 * 1024) {
e = E2BIG;
goto kill_conn;
}
conn->x.in.bufsize = conn->x.in.n_left = len;
conn->x.in.buf = conn->x.in.pos = malloc(len);
dprint("allocated %d byte buffer at %p\n", (int) len,
conn->x.in.buf);
if (conn->x.in.buf == 0) {
/* allocation failure */
e = ENOMEM;
goto kill_conn;
}
}
}
break;
default:
abort();
}
return 0;
}