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|
/*
* lib/krb5/os/sendto_kdc.c
*
* Copyright 1990,1991,2001,2002,2004,2005 by the Massachusetts Institute of Technology.
* All Rights Reserved.
*
* Export of this software from the United States of America may
* require a specific license from the United States Government.
* It is the responsibility of any person or organization contemplating
* export to obtain such a license before exporting.
*
* WITHIN THAT CONSTRAINT, permission to use, copy, modify, and
* distribute this software and its documentation for any purpose and
* without fee is hereby granted, provided that the above copyright
* notice appear in all copies and that both that copyright notice and
* this permission notice appear in supporting documentation, and that
* the name of M.I.T. not be used in advertising or publicity pertaining
* to distribution of the software without specific, written prior
* permission. Furthermore if you modify this software you must label
* your software as modified software and not distribute it in such a
* fashion that it might be confused with the original M.I.T. software.
* M.I.T. makes no representations about the suitability of
* this software for any purpose. It is provided "as is" without express
* or implied warranty.
*
*
* Send packet to KDC for realm; wait for response, retransmitting
* as necessary.
*/
#include "fake-addrinfo.h"
#include "k5-int.h"
#ifdef HAVE_SYS_TIME_H
#include <sys/time.h>
#else
#include <time.h>
#endif
#include "os-proto.h"
#ifdef _WIN32
#include <sys/timeb.h>
#endif
#ifdef _AIX
#include <sys/select.h>
#endif
#ifndef _WIN32
/* For FIONBIO. */
#include <sys/ioctl.h>
#ifdef HAVE_SYS_FILIO_H
#include <sys/filio.h>
#endif
#endif
#define MAX_PASS 3
#define DEFAULT_UDP_PREF_LIMIT 1465
#define HARD_UDP_LIMIT 32700 /* could probably do 64K-epsilon ? */
#undef DEBUG
#ifdef DEBUG
int krb5int_debug_sendto_kdc = 0;
#define debug krb5int_debug_sendto_kdc
static void default_debug_handler (const void *data, size_t len)
{
#if 0
static FILE *logfile;
if (logfile == NULL) {
logfile = fopen("/tmp/sendto_kdc.log", "a");
if (logfile == NULL)
return;
setbuf(logfile, NULL);
}
fwrite(data, 1, len, logfile);
#else
fwrite(data, 1, len, stderr);
/* stderr is unbuffered */
#endif
}
void (*krb5int_sendtokdc_debug_handler) (const void *, size_t) = default_debug_handler;
static void put(const void *ptr, size_t len)
{
(*krb5int_sendtokdc_debug_handler)(ptr, len);
}
static void putstr(const char *str)
{
put(str, strlen(str));
}
#else
void (*krb5int_sendtokdc_debug_handler) (const void *, size_t) = 0;
#endif
#define dprint krb5int_debug_fprint
void
krb5int_debug_fprint (const char *fmt, ...)
{
#ifdef DEBUG
va_list args;
/* Temporaries for variable arguments, etc. */
krb5_error_code kerr;
int err;
fd_set *rfds, *wfds, *xfds;
int i;
int maxfd;
struct timeval *tv;
struct addrinfo *ai;
const krb5_data *d;
char addrbuf[NI_MAXHOST], portbuf[NI_MAXSERV];
const char *p;
#ifndef max
#define max(a,b) ((a) > (b) ? (a) : (b))
#endif
char tmpbuf[max(NI_MAXHOST + NI_MAXSERV + 30, 200)];
if (!krb5int_debug_sendto_kdc)
return;
va_start(args, fmt);
#define putf(FMT,X) (sprintf(tmpbuf,FMT,X),putstr(tmpbuf))
for (; *fmt; fmt++) {
if (*fmt != '%') {
const char *fmt2;
size_t len;
for (fmt2 = fmt+1; *fmt2; fmt2++)
if (*fmt2 == '%')
break;
len = fmt2 - fmt;
if (0) {
FILE *f = fopen("/dev/pts/0", "w+");
if (f) {
fprintf(f, "krb5int_debug_fprint: format <%s> fmt2 <%s> put %lu next <%s>\n",
fmt, fmt2, (unsigned long) len, fmt+len-1);
}
}
put(fmt, len);
fmt += len - 1; /* then fmt++ in loop header */
continue;
}
/* After this, always processing a '%' sequence. */
fmt++;
switch (*fmt) {
case 0:
default:
abort();
case 'E':
/* %E => krb5_error_code */
kerr = va_arg(args, krb5_error_code);
sprintf(tmpbuf, "%lu/", (unsigned long) kerr);
putstr(tmpbuf);
p = error_message(kerr);
putstr(p);
break;
case 'm':
/* %m => errno value (int) */
/* Like syslog's %m except the errno value is passed in
rather than the current value. */
err = va_arg(args, int);
putf("%d/", err);
p = NULL;
#ifdef HAVE_STRERROR_R
if (strerror_r(err, tmpbuf, sizeof(tmpbuf)) == 0)
p = tmpbuf;
#endif
if (p == NULL)
p = strerror(err);
putstr(p);
break;
case 'F':
/* %F => fd_set *, fd_set *, fd_set *, int */
rfds = va_arg(args, fd_set *);
wfds = va_arg(args, fd_set *);
xfds = va_arg(args, fd_set *);
maxfd = va_arg(args, int);
for (i = 0; i < maxfd; i++) {
int r = FD_ISSET(i, rfds);
int w = wfds && FD_ISSET(i, wfds);
int x = xfds && FD_ISSET(i, xfds);
if (r || w || x) {
putf(" %d", i);
if (r)
putstr("r");
if (w)
putstr("w");
if (x)
putstr("x");
}
}
putstr(" ");
break;
case 's':
/* %s => char * */
p = va_arg(args, const char *);
putstr(p);
break;
case 't':
/* %t => struct timeval * */
tv = va_arg(args, struct timeval *);
if (tv) {
sprintf(tmpbuf, "%ld.%06ld",
(long) tv->tv_sec, (long) tv->tv_usec);
putstr(tmpbuf);
} else
putstr("never");
break;
case 'd':
/* %d => int */
putf("%d", va_arg(args, int));
break;
case 'p':
/* %p => pointer */
putf("%p", va_arg(args, void*));
break;
case 'A':
/* %A => addrinfo */
ai = va_arg(args, struct addrinfo *);
if (ai->ai_socktype == SOCK_DGRAM)
strcpy(tmpbuf, "dgram");
else if (ai->ai_socktype == SOCK_STREAM)
strcpy(tmpbuf, "stream");
else
sprintf(tmpbuf, "socktype%d", ai->ai_socktype);
if (0 != getnameinfo (ai->ai_addr, ai->ai_addrlen,
addrbuf, sizeof (addrbuf),
portbuf, sizeof (portbuf),
NI_NUMERICHOST | NI_NUMERICSERV)) {
if (ai->ai_addr->sa_family == AF_UNSPEC)
strcpy(tmpbuf + strlen(tmpbuf), " AF_UNSPEC");
else
sprintf(tmpbuf + strlen(tmpbuf), " af%d", ai->ai_addr->sa_family);
} else
sprintf(tmpbuf + strlen(tmpbuf), " %s.%s", addrbuf, portbuf);
putstr(tmpbuf);
break;
case 'D':
/* %D => krb5_data * */
d = va_arg(args, krb5_data *);
/* may not be nul-terminated */
put(d->data, d->length);
break;
}
}
va_end(args);
#endif
}
#define print_addrlist krb5int_print_addrlist
static void
print_addrlist (const struct addrlist *a)
{
int i;
dprint("%d{", a->naddrs);
for (i = 0; i < a->naddrs; i++)
dprint("%s%p=%A", i ? "," : "", (void*)a->addrs[i].ai, a->addrs[i].ai);
dprint("}");
}
static int
merge_addrlists (struct addrlist *dest, struct addrlist *src)
{
/* Wouldn't it be nice if we could filter out duplicates? The
alloc/free handling makes that pretty difficult though. */
int err, i;
dprint("merging addrlists:\n\tlist1: ");
for (i = 0; i < dest->naddrs; i++)
dprint(" %A", dest->addrs[i].ai);
dprint("\n\tlist2: ");
for (i = 0; i < src->naddrs; i++)
dprint(" %A", src->addrs[i].ai);
dprint("\n");
err = krb5int_grow_addrlist (dest, src->naddrs);
if (err)
return err;
for (i = 0; i < src->naddrs; i++) {
dest->addrs[dest->naddrs + i] = src->addrs[i];
src->addrs[i].ai = 0;
src->addrs[i].freefn = 0;
}
dest->naddrs += i;
src->naddrs = 0;
dprint("\tout: ");
for (i = 0; i < dest->naddrs; i++)
dprint(" %A", dest->addrs[i].ai);
dprint("\n");
return 0;
}
static int
in_addrlist (struct addrinfo *thisaddr, struct addrlist *list)
{
int i;
for (i = 0; i < list->naddrs; i++) {
if (thisaddr->ai_addrlen == list->addrs[i].ai->ai_addrlen
&& !memcmp(thisaddr->ai_addr, list->addrs[i].ai->ai_addr,
thisaddr->ai_addrlen))
return 1;
}
return 0;
}
/*
* send the formatted request 'message' to a KDC for realm 'realm' and
* return the response (if any) in 'reply'.
*
* If the message is sent and a response is received, 0 is returned,
* otherwise an error code is returned.
*
* The storage for 'reply' is allocated and should be freed by the caller
* when finished.
*/
krb5_error_code
krb5_sendto_kdc (krb5_context context, const krb5_data *message,
const krb5_data *realm, krb5_data *reply,
int *use_master, int tcp_only)
{
krb5_error_code retval, retval2;
struct addrlist addrs;
int socktype1 = 0, socktype2 = 0, addr_used;
/*
* find KDC location(s) for realm
*/
/*
* BUG: This code won't return "interesting" errors (e.g., out of mem,
* bad config file) from locate_kdc. KRB5_REALM_CANT_RESOLVE can be
* ignored from one query of two, but if only one query is done, or
* both return that error, it should be returned to the caller. Also,
* "interesting" errors (not KRB5_KDC_UNREACH) from sendto_{udp,tcp}
* should probably be returned as well.
*/
dprint("krb5_sendto_kdc(%d@%p, \"%D\", use_master=%d, tcp_only=%d)\n",
message->length, message->data, realm, *use_master, tcp_only);
if (!tcp_only && context->udp_pref_limit < 0) {
int tmp;
retval = profile_get_integer(context->profile,
"libdefaults", "udp_preference_limit", 0,
DEFAULT_UDP_PREF_LIMIT, &tmp);
if (retval)
return retval;
if (tmp < 0)
tmp = DEFAULT_UDP_PREF_LIMIT;
else if (tmp > HARD_UDP_LIMIT)
/* In the unlikely case that a *really* big value is
given, let 'em use as big as we think we can
support. */
tmp = HARD_UDP_LIMIT;
context->udp_pref_limit = tmp;
}
retval = (*use_master ? KRB5_KDC_UNREACH : KRB5_REALM_UNKNOWN);
if (tcp_only)
socktype1 = SOCK_STREAM, socktype2 = 0;
else if (message->length <= context->udp_pref_limit)
socktype1 = SOCK_DGRAM, socktype2 = SOCK_STREAM;
else
socktype1 = SOCK_STREAM, socktype2 = SOCK_DGRAM;
retval = krb5_locate_kdc(context, realm, &addrs, *use_master, socktype1, 0);
if (socktype2) {
struct addrlist addrs2;
retval2 = krb5_locate_kdc(context, realm, &addrs2, *use_master,
socktype2, 0);
#if 0
if (retval2 == 0) {
(void) merge_addrlists(&addrs, &addrs2);
krb5int_free_addrlist(&addrs2);
retval = 0;
} else if (retval == KRB5_REALM_CANT_RESOLVE) {
retval = retval2;
}
#else
retval = retval2;
if (retval == 0) {
(void) merge_addrlists(&addrs, &addrs2);
krb5int_free_addrlist(&addrs2);
}
#endif
}
if (addrs.naddrs > 0) {
retval = krb5int_sendto (context, message, &addrs, 0, reply, 0, 0,
0, 0, &addr_used);
switch (retval) {
case 0:
/*
* Set use_master to 1 if we ended up talking to a master when
* we didn't explicitly request to
*/
if (*use_master == 0) {
struct addrlist addrs3;
retval = krb5_locate_kdc(context, realm, &addrs3, 1,
addrs.addrs[addr_used].ai->ai_socktype,
addrs.addrs[addr_used].ai->ai_family);
if (retval == 0) {
if (in_addrlist(addrs.addrs[addr_used].ai, &addrs3))
*use_master = 1;
krb5int_free_addrlist (&addrs3);
}
}
krb5int_free_addrlist (&addrs);
return 0;
default:
break;
/* Cases here are for constructing useful error messages. */
case KRB5_KDC_UNREACH:
krb5_set_error_message(context, retval,
"Cannot contact any KDC for realm '%.*s'",
realm->length, realm->data);
break;
}
krb5int_free_addrlist (&addrs);
}
return retval;
}
#ifdef DEBUG
#ifdef _WIN32
#define dperror(MSG) \
dprint("%s: an error occurred ... " \
"\tline=%d errno=%m socketerrno=%m\n", \
(MSG), __LINE__, errno, SOCKET_ERRNO)
#else
#define dperror(MSG) dprint("%s: %m\n", MSG, errno)
#endif
#define dfprintf(ARGLIST) (debug ? fprintf ARGLIST : 0)
#else /* ! DEBUG */
#define dperror(MSG) ((void)(MSG))
#define dfprintf(ARGLIST) ((void)0)
#endif
/*
* Notes:
*
* Getting "connection refused" on a connected UDP socket causes
* select to indicate write capability on UNIX, but only shows up
* as an exception on Windows. (I don't think any UNIX system flags
* the error as an exception.) So we check for both, or make it
* system-specific.
*
* Always watch for responses from *any* of the servers. Eventually
* fix the UDP code to do the same.
*
* To do:
* - TCP NOPUSH/CORK socket options?
* - error codes that don't suck
* - getsockopt(SO_ERROR) to check connect status
* - handle error RESPONSE_TOO_BIG from UDP server and use TCP
* connections already in progress
*/
#include "cm.h"
static int getcurtime (struct timeval *tvp)
{
#ifdef _WIN32
struct _timeb tb;
_ftime(&tb);
tvp->tv_sec = tb.time;
tvp->tv_usec = tb.millitm * 1000;
/* Can _ftime fail? */
return 0;
#else
if (gettimeofday(tvp, 0)) {
dperror("gettimeofday");
return errno;
}
return 0;
#endif
}
/*
* Call select and return results.
* Input: interesting file descriptors and absolute timeout
* Output: select return value (-1 or num fds ready) and fd_sets
* Return: 0 (for i/o available or timeout) or error code.
*/
krb5_error_code
krb5int_cm_call_select (const struct select_state *in,
struct select_state *out, int *sret)
{
struct timeval now, *timo;
krb5_error_code e;
*out = *in;
e = getcurtime(&now);
if (e)
return e;
if (out->end_time.tv_sec == 0)
timo = 0;
else {
timo = &out->end_time;
out->end_time.tv_sec -= now.tv_sec;
out->end_time.tv_usec -= now.tv_usec;
if (out->end_time.tv_usec < 0) {
out->end_time.tv_usec += 1000000;
out->end_time.tv_sec--;
}
if (out->end_time.tv_sec < 0) {
*sret = 0;
return 0;
}
}
dprint("selecting on max=%d sockets [%F] timeout %t\n",
out->max,
&out->rfds, &out->wfds, &out->xfds, out->max,
timo);
*sret = select(out->max, &out->rfds, &out->wfds, &out->xfds, timo);
e = SOCKET_ERRNO;
dprint("select returns %d", *sret);
if (*sret < 0)
dprint(", error = %E\n", e);
else if (*sret == 0)
dprint(" (timeout)\n");
else
dprint(":%F\n", &out->rfds, &out->wfds, &out->xfds, out->max);
if (*sret < 0)
return e;
return 0;
}
static int service_tcp_fd (struct conn_state *conn,
struct select_state *selstate, int ssflags);
static int service_udp_fd (struct conn_state *conn,
struct select_state *selstate, int ssflags);
static void
set_conn_state_msg_length (struct conn_state *state, const krb5_data *message)
{
if (!message || message->length == 0)
return;
if (!state->is_udp) {
state->x.out.msg_len_buf[0] = (message->length >> 24) & 0xff;
state->x.out.msg_len_buf[1] = (message->length >> 16) & 0xff;
state->x.out.msg_len_buf[2] = (message->length >> 8) & 0xff;
state->x.out.msg_len_buf[3] = message->length & 0xff;
SG_SET(&state->x.out.sgbuf[0], state->x.out.msg_len_buf, 4);
SG_SET(&state->x.out.sgbuf[1], message->data, message->length);
state->x.out.sg_count = 2;
} else {
SG_SET(&state->x.out.sgbuf[0], message->data, message->length);
SG_SET(&state->x.out.sgbuf[1], 0, 0);
state->x.out.sg_count = 1;
}
}
static int
setup_connection (struct conn_state *state, struct addrinfo *ai,
const krb5_data *message, char **udpbufp)
{
state->state = INITIALIZING;
state->err = 0;
state->x.out.sgp = state->x.out.sgbuf;
state->addr = ai;
state->fd = INVALID_SOCKET;
SG_SET(&state->x.out.sgbuf[1], 0, 0);
if (ai->ai_socktype == SOCK_STREAM) {
/*
SG_SET(&state->x.out.sgbuf[0], message_len_buf, 4);
SG_SET(&state->x.out.sgbuf[1], message->data, message->length);
state->x.out.sg_count = 2;
*/
state->is_udp = 0;
state->service = service_tcp_fd;
set_conn_state_msg_length (state, message);
} else {
/*
SG_SET(&state->x.out.sgbuf[0], message->data, message->length);
SG_SET(&state->x.out.sgbuf[1], 0, 0);
state->x.out.sg_count = 1;
*/
state->is_udp = 1;
state->service = service_udp_fd;
set_conn_state_msg_length (state, message);
if (*udpbufp == 0) {
*udpbufp = malloc(krb5_max_dgram_size);
if (*udpbufp == 0) {
dperror("malloc(krb5_max_dgram_size)");
(void) closesocket(state->fd);
state->fd = INVALID_SOCKET;
state->state = FAILED;
return 1;
}
}
state->x.in.buf = *udpbufp;
state->x.in.bufsize = krb5_max_dgram_size;
}
return 0;
}
static int
start_connection (struct conn_state *state,
struct select_state *selstate,
struct sendto_callback_info* callback_info,
krb5_data* callback_buffer)
{
int fd, e;
struct addrinfo *ai = state->addr;
dprint("start_connection(@%p)\ngetting %s socket in family %d...", state,
ai->ai_socktype == SOCK_STREAM ? "stream" : "dgram", ai->ai_family);
fd = socket(ai->ai_family, ai->ai_socktype, 0);
if (fd == INVALID_SOCKET) {
state->err = SOCKET_ERRNO;
dprint("socket: %m creating with af %d\n", state->err, ai->ai_family);
return -1; /* try other hosts */
}
/* Make it non-blocking. */
if (ai->ai_socktype == SOCK_STREAM) {
static const int one = 1;
static const struct linger lopt = { 0, 0 };
if (ioctlsocket(fd, FIONBIO, (const void *) &one))
dperror("sendto_kdc: ioctl(FIONBIO)");
if (setsockopt(fd, SOL_SOCKET, SO_LINGER, &lopt, sizeof(lopt)))
dperror("sendto_kdc: setsockopt(SO_LINGER)");
}
/* Start connecting to KDC. */
dprint(" fd %d; connecting to %A...\n", fd, ai);
e = connect(fd, ai->ai_addr, ai->ai_addrlen);
if (e != 0) {
/*
* This is the path that should be followed for non-blocking
* connections.
*/
if (SOCKET_ERRNO == EINPROGRESS || SOCKET_ERRNO == EWOULDBLOCK) {
state->state = CONNECTING;
state->fd = fd;
} else {
dprint("connect failed: %m\n", SOCKET_ERRNO);
(void) closesocket(fd);
state->err = SOCKET_ERRNO;
state->state = FAILED;
return -2;
}
} else {
/*
* Connect returned zero even though we tried to make it
* non-blocking, which should have caused it to return before
* finishing the connection. Oh well. Someone's network
* stack is broken, but if they gave us a connection, use it.
*/
state->state = WRITING;
state->fd = fd;
}
dprint("new state = %s\n", state_strings[state->state]);
/*
* Here's where KPASSWD callback gets the socket information it needs for
* a kpasswd request
*/
if (callback_info) {
e = callback_info->pfn_callback(state,
callback_info->context,
callback_buffer);
if (e != 0) {
dprint("callback failed: %m\n", e);
(void) closesocket(fd);
state->err = e;
state->fd = INVALID_SOCKET;
state->state = FAILED;
return -3;
}
dprint("callback %p (message=%d@%p)\n",
state,
callback_buffer->length,
callback_buffer->data);
set_conn_state_msg_length( state, callback_buffer );
}
if (ai->ai_socktype == SOCK_DGRAM) {
/* Send it now. */
int ret;
sg_buf *sg = &state->x.out.sgbuf[0];
dprint("sending %d bytes on fd %d\n", SG_LEN(sg), state->fd);
ret = send(state->fd, SG_BUF(sg), SG_LEN(sg), 0);
if (ret != SG_LEN(sg)) {
dperror("sendto");
(void) closesocket(state->fd);
state->fd = INVALID_SOCKET;
state->state = FAILED;
return -4;
} else {
state->state = READING;
}
}
#ifdef DEBUG
if (debug) {
struct sockaddr_storage ss;
socklen_t sslen = sizeof(ss);
if (getsockname(state->fd, (struct sockaddr *)&ss, &sslen) == 0) {
struct addrinfo hack_ai;
memset(&hack_ai, 0, sizeof(hack_ai));
hack_ai.ai_addr = (struct sockaddr *) &ss;
hack_ai.ai_addrlen = sslen;
hack_ai.ai_socktype = SOCK_DGRAM;
hack_ai.ai_family = ai->ai_family;
dprint("local socket address is %A\n", &hack_ai);
}
}
#endif
FD_SET(state->fd, &selstate->rfds);
if (state->state == CONNECTING || state->state == WRITING)
FD_SET(state->fd, &selstate->wfds);
FD_SET(state->fd, &selstate->xfds);
if (selstate->max <= state->fd)
selstate->max = state->fd + 1;
selstate->nfds++;
dprint("new select vectors: %F\n",
&selstate->rfds, &selstate->wfds, &selstate->xfds, selstate->max);
return 0;
}
/* Return 0 if we sent something, non-0 otherwise.
If 0 is returned, the caller should delay waiting for a response.
Otherwise, the caller should immediately move on to process the
next connection. */
static int
maybe_send (struct conn_state *conn,
struct select_state *selstate,
struct sendto_callback_info* callback_info,
krb5_data* callback_buffer)
{
sg_buf *sg;
dprint("maybe_send(@%p) state=%s type=%s\n", conn,
state_strings[conn->state],
conn->is_udp ? "udp" : "tcp");
if (conn->state == INITIALIZING)
return start_connection(conn, selstate, callback_info, callback_buffer);
/* Did we already shut down this channel? */
if (conn->state == FAILED) {
dprint("connection already closed\n");
return -1;
}
if (conn->addr->ai_socktype == SOCK_STREAM) {
dprint("skipping stream socket\n");
/* The select callback will handle flushing any data we
haven't written yet, and we only write it once. */
return -1;
}
/* UDP - Send message, possibly for the first time, possibly a
retransmit if a previous attempt timed out. */
sg = &conn->x.out.sgbuf[0];
dprint("sending %d bytes on fd %d\n", SG_LEN(sg), conn->fd);
if (send(conn->fd, SG_BUF(sg), SG_LEN(sg), 0) != SG_LEN(sg)) {
dperror("send");
/* Keep connection alive, we'll try again next pass.
Is this likely to catch any errors we didn't get from the
select callbacks? */
return -1;
}
/* Yay, it worked. */
return 0;
}
static void
kill_conn(struct conn_state *conn, struct select_state *selstate, int err)
{
conn->state = FAILED;
shutdown(conn->fd, SHUTDOWN_BOTH);
FD_CLR(conn->fd, &selstate->rfds);
FD_CLR(conn->fd, &selstate->wfds);
FD_CLR(conn->fd, &selstate->xfds);
conn->err = err;
dprint("abandoning connection %d: %m\n", conn->fd, err);
/* Fix up max fd for next select call. */
if (selstate->max == 1 + conn->fd) {
while (selstate->max > 0
&& ! FD_ISSET(selstate->max-1, &selstate->rfds)
&& ! FD_ISSET(selstate->max-1, &selstate->wfds)
&& ! FD_ISSET(selstate->max-1, &selstate->xfds))
selstate->max--;
dprint("new max_fd + 1 is %d\n", selstate->max);
}
selstate->nfds--;
}
/* Check socket for error. */
static int
get_so_error(int fd)
{
int e, sockerr;
socklen_t sockerrlen;
sockerr = 0;
sockerrlen = sizeof(sockerr);
e = getsockopt(fd, SOL_SOCKET, SO_ERROR, &sockerr, &sockerrlen);
if (e != 0) {
/* What to do now? */
e = SOCKET_ERRNO;
dprint("getsockopt(SO_ERROR) on fd failed: %m\n", e);
return e;
}
return sockerr;
}
/* Return nonzero only if we're finished and the caller should exit
its loop. This happens in two cases: We have a complete message,
or the socket has closed and no others are open. */
static int
service_tcp_fd (struct conn_state *conn, struct select_state *selstate,
int ssflags)
{
krb5_error_code e = 0;
int 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:
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) {
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);
nwritten = SOCKET_WRITEV(conn->fd, conn->x.out.sgp,
conn->x.out.sg_count, tmp);
if (nwritten < 0) {
e = SOCKET_ERRNO;
dprint("failed: %m\n", e);
goto kill_conn;
}
dprint("wrote %d bytes\n", nwritten);
while (nwritten) {
sg_buf *sgp = conn->x.out.sgp;
if (nwritten < SG_LEN(sgp)) {
SG_ADVANCE(sgp, nwritten);
nwritten = 0;
} else {
nwritten -= SG_LEN(conn->x.out.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;
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) {
e = SOCKET_ERRNO;
goto kill_conn;
}
conn->x.in.bufsizebytes_read += nread;
if (conn->x.in.bufsizebytes_read == 4) {
unsigned long len;
len = conn->x.in.bufsizebytes[0];
len = (len << 8) + conn->x.in.bufsizebytes[1];
len = (len << 8) + conn->x.in.bufsizebytes[2];
len = (len << 8) + conn->x.in.bufsizebytes[3];
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 = errno;
goto kill_conn;
}
}
}
break;
default:
abort();
}
return 0;
}
static int
service_udp_fd(struct conn_state *conn, struct select_state *selstate,
int ssflags)
{
int nread;
if (!(ssflags & (SSF_READ|SSF_EXCEPTION)))
abort();
if (conn->state != READING)
abort();
nread = recv(conn->fd, conn->x.in.buf, conn->x.in.bufsize, 0);
if (nread < 0) {
kill_conn(conn, selstate, SOCKET_ERRNO);
return 0;
}
conn->x.in.pos = conn->x.in.buf + nread;
return 1;
}
static int
service_fds (struct select_state *selstate,
struct conn_state *conns, size_t n_conns, int *winning_conn,
struct select_state *seltemp)
{
int e, selret;
e = 0;
while (selstate->nfds > 0) {
int i;
e = krb5int_cm_call_select(selstate, seltemp, &selret);
if (e == EINTR)
continue;
if (e != 0)
break;
dprint("service_fds examining results, selret=%d\n", selret);
if (selret == 0)
/* Timeout, return to caller. */
return 0;
/* Got something on a socket, process it. */
for (i = 0; i <= selstate->max && selret > 0 && i < n_conns; i++) {
int ssflags;
if (conns[i].fd == INVALID_SOCKET)
continue;
ssflags = 0;
if (FD_ISSET(conns[i].fd, &seltemp->rfds))
ssflags |= SSF_READ, selret--;
if (FD_ISSET(conns[i].fd, &seltemp->wfds))
ssflags |= SSF_WRITE, selret--;
if (FD_ISSET(conns[i].fd, &seltemp->xfds))
ssflags |= SSF_EXCEPTION, selret--;
if (!ssflags)
continue;
dprint("handling flags '%s%s%s' on fd %d (%A) in state %s\n",
(ssflags & SSF_READ) ? "r" : "",
(ssflags & SSF_WRITE) ? "w" : "",
(ssflags & SSF_EXCEPTION) ? "x" : "",
conns[i].fd, conns[i].addr,
state_strings[(int) conns[i].state]);
if (conns[i].service (&conns[i], selstate, ssflags)) {
dprint("fd service routine says we're done\n");
*winning_conn = i;
return 1;
}
}
}
if (e != 0) {
dprint("select returned %m\n", e);
*winning_conn = -1;
return 1;
}
return 0;
}
/*
* Current worst-case timeout behavior:
*
* First pass, 1s per udp or tcp server, plus 2s at end.
* Second pass, 1s per udp server, plus 4s.
* Third pass, 1s per udp server, plus 8s.
* Fourth => 16s, etc.
*
* Restated:
* Per UDP server, 1s per pass.
* Per TCP server, 1s.
* Backoff delay, 2**(P+1) - 2, where P is total number of passes.
*
* Total = 2**(P+1) + U*P + T - 2.
*
* If P=3, Total = 3*U + T + 14.
* If P=4, Total = 4*U + T + 30.
*
* Note that if you try to reach two ports (e.g., both 88 and 750) on
* one server, it counts as two.
*/
krb5_error_code
krb5int_sendto (krb5_context context, const krb5_data *message,
const struct addrlist *addrs,
struct sendto_callback_info* callback_info, krb5_data *reply,
struct sockaddr *localaddr, socklen_t *localaddrlen,
struct sockaddr *remoteaddr, socklen_t *remoteaddrlen,
int *addr_used)
{
int i, pass;
int delay_this_pass = 2;
krb5_error_code retval;
struct conn_state *conns;
krb5_data *callback_data = 0;
size_t n_conns, host;
struct select_state *sel_state;
struct timeval now;
int winning_conn = -1, e = 0;
char *udpbuf = 0;
if (message)
dprint("krb5int_sendto(message=%d@%p, addrlist=", message->length, message->data);
else
dprint("krb5int_sendto(callback=%p, addrlist=", callback_info);
print_addrlist(addrs);
dprint(")\n");
reply->data = 0;
reply->length = 0;
n_conns = addrs->naddrs;
conns = malloc(n_conns * sizeof(struct conn_state));
if (conns == NULL) {
return ENOMEM;
}
memset(conns, 0, n_conns * sizeof(struct conn_state));
if (callback_info) {
callback_data = malloc(n_conns * sizeof(krb5_data));
if (callback_data == NULL) {
return ENOMEM;
}
memset(callback_data, 0, n_conns * sizeof(krb5_data));
}
for (i = 0; i < n_conns; i++) {
conns[i].fd = INVALID_SOCKET;
}
/* One for use here, listing all our fds in use, and one for
temporary use in service_fds, for the fds of interest. */
sel_state = malloc(2 * sizeof(*sel_state));
if (sel_state == NULL) {
free(conns);
return ENOMEM;
}
sel_state->max = 0;
sel_state->nfds = 0;
sel_state->end_time.tv_sec = sel_state->end_time.tv_usec = 0;
FD_ZERO(&sel_state->rfds);
FD_ZERO(&sel_state->wfds);
FD_ZERO(&sel_state->xfds);
/* Set up connections. */
for (host = 0; host < n_conns; host++) {
retval = setup_connection(&conns[host],
addrs->addrs[host].ai,
message,
&udpbuf);
if (retval)
continue;
}
for (pass = 0; pass < MAX_PASS; pass++) {
/* Possible optimization: Make only one pass if TCP only.
Stop making passes if all UDP ports are closed down. */
dprint("pass %d delay=%d\n", pass, delay_this_pass);
for (host = 0; host < n_conns; host++) {
dprint("host %d\n", host);
/* Send to the host, wait for a response, then move on. */
if (maybe_send(&conns[host],
sel_state,
callback_info,
(callback_info ? &callback_data[host] : NULL)))
continue;
retval = getcurtime(&now);
if (retval)
goto egress;
sel_state->end_time = now;
sel_state->end_time.tv_sec += 1;
e = service_fds(sel_state, conns, host+1, &winning_conn,
sel_state+1);
if (e)
break;
if (pass > 0 && sel_state->nfds == 0)
/*
* After the first pass, if we close all fds, break
* out right away. During the first pass, it's okay,
* we're probably about to open another connection.
*/
break;
}
if (e)
break;
retval = getcurtime(&now);
if (retval)
goto egress;
/* Possible optimization: Find a way to integrate this select
call with the last one from the above loop, if the loop
actually calls select. */
sel_state->end_time.tv_sec += delay_this_pass;
e = service_fds(sel_state, conns, host+1, &winning_conn, sel_state+1);
if (e)
break;
if (sel_state->nfds == 0)
break;
delay_this_pass *= 2;
}
if (sel_state->nfds == 0) {
/* No addresses? */
retval = KRB5_KDC_UNREACH;
goto egress;
}
if (e == 0 || winning_conn < 0) {
retval = KRB5_KDC_UNREACH;
goto egress;
}
/* Success! */
reply->data = conns[winning_conn].x.in.buf;
reply->length = (conns[winning_conn].x.in.pos
- conns[winning_conn].x.in.buf);
dprint("returning %d bytes in buffer %p\n",
(int) reply->length, reply->data);
retval = 0;
conns[winning_conn].x.in.buf = 0;
if (addr_used)
*addr_used = winning_conn;
if (localaddr != 0 && localaddrlen != 0 && *localaddrlen > 0)
(void) getsockname(conns[winning_conn].fd, localaddr, localaddrlen);
if (remoteaddr != 0 && remoteaddrlen != 0 && *remoteaddrlen > 0)
(void) getpeername(conns[winning_conn].fd, remoteaddr, remoteaddrlen);
egress:
for (i = 0; i < n_conns; i++) {
if (conns[i].fd != INVALID_SOCKET)
closesocket(conns[i].fd);
if (conns[i].state == READING
&& conns[i].x.in.buf != 0
&& conns[i].x.in.buf != udpbuf)
free(conns[i].x.in.buf);
if (callback_info) {
callback_info->pfn_cleanup( callback_info->context, &callback_data[i]);
}
}
if (callback_data)
free(callback_data);
free(conns);
if (reply->data != udpbuf)
free(udpbuf);
free(sel_state);
return retval;
}
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