Specify and implement fragmented control messages to allow for (among other things) long GETINFO replies. Otherwise we could hit the 64K barrier on questions like "please dump your client-side DNS cache."

svn:r3726
This commit is contained in:
Nick Mathewson 2005-03-02 20:22:10 +00:00
parent 65230fd39f
commit b494c2223d
5 changed files with 186 additions and 66 deletions

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@ -62,7 +62,9 @@ N . Implement pending controller features.
o MAPADDRESS
o Map A->B.
o Map DontCare->B.
- Way to handle overlong messages?
o Way to handle overlong messages
o Specify fragmented format
o Implement fragmented format
- Event for "new descriptors"
o Better stream IDs
- EXTENDCIRCUIT <depends on revised circ selection stuff.>

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@ -51,6 +51,11 @@ the message.
3. Message types
Message types are drawn from the following ranges:
0x0000-0xEFFF : Reserved for use by official versions of this spec.
0xF000-0xFFFF : Unallocated; usable by unofficial extensions.
3.1. ERROR (Type 0x0000)
Sent in response to a message that could not be processed as requested.
@ -232,8 +237,6 @@ the message.
3.11. MAPADDRESS (Type 0x000A)
[Proposal; not finalized]
Sent from the client to the server. The body contains a sequence of
address mappings, each consisting of the address to be mapped, a single
space, the replacement address, and a NL character.
@ -279,8 +282,6 @@ the message.
3.12 GETINFO (Type 0x000B)
[Proposal; not finalized]
Sent from the client to the server. The message body is as for GETCONF:
one or more NL-terminated strings. The server replies with an INFOVALUE
message.
@ -304,8 +305,6 @@ the message.
3.13 INFOVALUE (Type 0x000C)
[Proposal; not finalized]
Sent from the server to the client in response to a GETINFO message.
Contains one or more items of the format:
@ -360,6 +359,32 @@ the message.
the descriptor for any reason, the server must send an appropriate error
message.
3.17 FRAGMENTHEADER (Type 0x0010)
[Proposal; not finalized]
Sent in either direction. Used to encapsulate messages longer than 65535
bytes long.
Underlying type [2 bytes]
Total Length [4 bytes]
Data [Rest of message]
A FRAGMENTHEADER message MUST be followed immediately by a number of
FRAGMENT messages, such that lengths of the "Data" fields of the
FRAGMENTHEADER and FRAGMENT messages add to the "Total Length" field of the
FRAGMENTHEADER message.
Implementations MUST NOT fragment messages of length less than 65536 bytes.
Implementations MUST be able to process fragmented messages that not
optimally packed.
3.18 FRAGMENT (Type 0x0011)
[Proposal; not finalized]
Data [Entire message]
4. Implementation notes
4.1. There are four ways we could authenticate, for now:

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@ -645,20 +645,24 @@ int fetch_from_buf_socks(buf_t *buf, socks_request_t *req) {
}
}
#define CONTROL_CMD_FRAGMENTHEADER 0x0010
#define CONTROL_CMD_FRAGMENT 0x0011
/** If there is a complete control message waiting on buf, then store
* its contents into *<b>type_out</b>, store its body's length into
* *<b>len_out</b>, allocate and store a string for its body into
* *<b>body_out</b>, and return -1. (body_out will always be NUL-terminated,
* *<b>body_out</b>, and return 1. (body_out will always be NUL-terminated,
* even if the control message body doesn't end with NUL.)
*
* If there is not a complete control message waiting, return 0.
*
* Return -1 on error.
*/
int fetch_from_buf_control(buf_t *buf, uint16_t *len_out, uint16_t *type_out,
int fetch_from_buf_control(buf_t *buf, uint32_t *len_out, uint16_t *type_out,
char **body_out)
{
uint16_t len;
uint32_t msglen;
uint16_t type;
tor_assert(buf);
tor_assert(len_out);
@ -668,23 +672,82 @@ int fetch_from_buf_control(buf_t *buf, uint16_t *len_out, uint16_t *type_out,
if (buf->datalen < 4)
return 0;
len = ntohs(get_uint16(buf->mem));
if (buf->datalen < 4 + (unsigned)len)
msglen = ntohs(get_uint16(buf->mem));
if (buf->datalen < 4 + (unsigned)msglen)
return 0;
*len_out = len;
*type_out = ntohs(get_uint16(buf->mem+2));
if (len) {
*body_out = tor_malloc(len+1);
memcpy(*body_out, buf->mem+4, len);
(*body_out)[len] = '\0';
type = ntohs(get_uint16(buf->mem+2));
if (type != CONTROL_CMD_FRAGMENTHEADER) {
*len_out = msglen;
*type_out = type;
if (msglen) {
*body_out = tor_malloc(msglen+1);
memcpy(*body_out, buf->mem+4, msglen);
(*body_out)[msglen] = '\0';
} else {
*body_out = NULL;
}
buf_remove_from_front(buf, 4+msglen);
return 1;
} else {
*body_out = NULL;
uint32_t totallen, sofar;
char *cp, *endp, *outp;
/* Okay, we have a fragmented message. Is it all here? */
if (msglen < 6)
return -1;
type = htons(get_uint16(buf->mem+4));
totallen = htonl(get_uint32(buf->mem+6));
if (totallen < 65536)
return -1;
if (buf->datalen<4+6+totallen)
/* The data can't possibly be here yet, no matter how well it's packed.*/
return 0;
/* Count how much data is really here. */
sofar = msglen-6;
cp = buf->mem+4+msglen;
endp = buf->mem+buf->datalen;
while (sofar < totallen) {
if ((endp-cp)<4)
return 0; /* Fragment header not all here. */
msglen = ntohs(get_uint16(cp));
if (ntohs(get_uint16(cp+2) != CONTROL_CMD_FRAGMENT))
return -1; /* Missing fragment message; error. */
if ((endp-cp) < 4+msglen)
return 0; /* Fragment not all here. */
sofar += msglen;
cp += (4+msglen);
}
if (sofar > totallen)
return -1; /* Fragments add to more than expected; error. */
/* Okay, everything is here. */
*len_out = totallen;
*type_out = type;
*body_out = tor_malloc(totallen+1);
/* copy FRAGMENTED packet contents. */
msglen = ntohs(get_uint16(buf->mem));
if (msglen>6)
memcpy(*body_out,buf->mem+4+6,msglen-6);
sofar = msglen-6;
outp = *body_out+sofar;
cp = buf->mem+4+msglen;
while (sofar < totallen) {
msglen = ntohs(get_uint16(cp));
memcpy(outp,cp+4,msglen);
outp += msglen;
cp += 4+msglen;
sofar -= msglen;
}
(*body_out)[totallen]='\0';
return 1;
}
buf_remove_from_front(buf, 4+len);
return 1;
}
/** Log an error and exit if <b>buf</b> is corrupted.

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@ -46,7 +46,9 @@ const char control_c_id[] = "$Id$";
#define CONTROL_CMD_EXTENDCIRCUIT 0x000D
#define CONTROL_CMD_ATTACHSTREAM 0x000E
#define CONTROL_CMD_POSTDESCRIPTOR 0x000F
#define _CONTROL_CMD_MAX_RECOGNIZED 0x000F
#define CONTROL_CMD_FRAGMENTHEADER 0x0010
#define CONTROL_CMD_FRAGMENT 0x0011
#define _CONTROL_CMD_MAX_RECOGNIZED 0x0011
/* Recognized error codes. */
#define ERR_UNSPECIFIED 0x0000
@ -89,7 +91,9 @@ static const char * CONTROL_COMMANDS[_CONTROL_CMD_MAX_RECOGNIZED+1] = {
"infovalue",
"extendcircuit",
"attachstream",
"postdescriptor"
"postdescriptor",
"fragmentheader",
"fragment",
};
/** Bitfield: The bit 1&lt;&lt;e is set if <b>any</b> open control
@ -115,33 +119,33 @@ static char authentication_cookie[AUTHENTICATION_COOKIE_LEN];
static void update_global_event_mask(void);
static void send_control_message(connection_t *conn, uint16_t type,
uint16_t len, const char *body);
uint32_t len, const char *body);
static void send_control_done(connection_t *conn);
static void send_control_done2(connection_t *conn, const char *msg, size_t len);
static void send_control_error(connection_t *conn, uint16_t error,
const char *message);
static void send_control_event(uint16_t event, uint16_t len, const char *body);
static int handle_control_setconf(connection_t *conn, uint16_t len,
static void send_control_event(uint16_t event, uint32_t len, const char *body);
static int handle_control_setconf(connection_t *conn, uint32_t len,
char *body);
static int handle_control_getconf(connection_t *conn, uint16_t len,
static int handle_control_getconf(connection_t *conn, uint32_t len,
const char *body);
static int handle_control_setevents(connection_t *conn, uint16_t len,
static int handle_control_setevents(connection_t *conn, uint32_t len,
const char *body);
static int handle_control_authenticate(connection_t *conn, uint16_t len,
static int handle_control_authenticate(connection_t *conn, uint32_t len,
const char *body);
static int handle_control_saveconf(connection_t *conn, uint16_t len,
static int handle_control_saveconf(connection_t *conn, uint32_t len,
const char *body);
static int handle_control_signal(connection_t *conn, uint16_t len,
static int handle_control_signal(connection_t *conn, uint32_t len,
const char *body);
static int handle_control_mapaddress(connection_t *conn, uint16_t len,
static int handle_control_mapaddress(connection_t *conn, uint32_t len,
const char *body);
static int handle_control_getinfo(connection_t *conn, uint16_t len,
static int handle_control_getinfo(connection_t *conn, uint32_t len,
const char *body);
static int handle_control_extendcircuit(connection_t *conn, uint16_t len,
static int handle_control_extendcircuit(connection_t *conn, uint32_t len,
const char *body);
static int handle_control_attachstream(connection_t *conn, uint16_t len,
static int handle_control_attachstream(connection_t *conn, uint32_t len,
const char *body);
static int handle_control_postdescriptor(connection_t *conn, uint16_t len,
static int handle_control_postdescriptor(connection_t *conn, uint32_t len,
const char *body);
/** Given a possibly invalid message type code <b>cmd</b>, return a
@ -172,18 +176,38 @@ static void update_global_event_mask(void)
/** Send a message of type <b>type</b> containing <b>len</b> bytes
* from <b>body</b> along the control connection <b>conn</b> */
static void
send_control_message(connection_t *conn, uint16_t type, uint16_t len,
send_control_message(connection_t *conn, uint16_t type, uint32_t len,
const char *body)
{
char buf[4];
char buf[10];
tor_assert(conn);
tor_assert(len || !body);
tor_assert(type <= _CONTROL_CMD_MAX_RECOGNIZED);
set_uint16(buf, htons(len));
set_uint16(buf+2, htons(type));
connection_write_to_buf(buf, 4, conn);
if (len)
connection_write_to_buf(body, len, conn);
if (len < 65536) {
set_uint16(buf, htons(len));
set_uint16(buf+2, htons(type));
connection_write_to_buf(buf, 4, conn);
if (len)
connection_write_to_buf(body, len, conn);
} else {
set_uint16(buf, htons(65535));
set_uint16(buf+2, htons(CONTROL_CMD_FRAGMENTHEADER));
set_uint16(buf+4, htons(type));
set_uint32(buf+6, htonl(len));
connection_write_to_buf(buf, 10, conn);
connection_write_to_buf(body, 65535-6, conn);
len -= (65535-6);
body += (65535-6);
while (len) {
size_t chunklen = (len<65535)?len:65535;
set_uint16(buf, htons((uint16_t)chunklen));
set_uint16(buf+2, htons(CONTROL_CMD_FRAGMENT));
connection_write_to_buf(buf, 4, conn);
connection_write_to_buf(body, chunklen, conn);
len -= chunklen;
body += chunklen;
}
}
}
/** Send a "DONE" message down the control connection <b>conn</b> */
@ -216,7 +240,7 @@ send_control_error(connection_t *conn, uint16_t error, const char *message)
* <b>len</b> bytes in <b>body</b> to every control connection that
* is interested in it. */
static void
send_control_event(uint16_t event, uint16_t len, const char *body)
send_control_event(uint16_t event, uint32_t len, const char *body)
{
connection_t **conns;
int n_conns, i;
@ -233,7 +257,7 @@ send_control_event(uint16_t event, uint16_t len, const char *body)
if (conns[i]->type == CONN_TYPE_CONTROL &&
conns[i]->state == CONTROL_CONN_STATE_OPEN &&
conns[i]->event_mask & (1<<event)) {
send_control_message(conns[i], CONTROL_CMD_EVENT, (uint16_t)(buflen), buf);
send_control_message(conns[i], CONTROL_CMD_EVENT, buflen, buf);
}
}
@ -243,7 +267,7 @@ send_control_event(uint16_t event, uint16_t len, const char *body)
/** Called when we receive a SETCONF message: parse the body and try
* to update our configuration. Reply with a DONE or ERROR message. */
static int
handle_control_setconf(connection_t *conn, uint16_t len, char *body)
handle_control_setconf(connection_t *conn, uint32_t len, char *body)
{
int r;
struct config_line_t *lines=NULL;
@ -278,7 +302,7 @@ handle_control_setconf(connection_t *conn, uint16_t len, char *body)
/** Called when we receive a GETCONF message. Parse the request, and
* reply with a CONFVALUE or an ERROR message */
static int
handle_control_getconf(connection_t *conn, uint16_t body_len, const char *body)
handle_control_getconf(connection_t *conn, uint32_t body_len, const char *body)
{
smartlist_t *questions = NULL;
smartlist_t *answers = NULL;
@ -332,7 +356,7 @@ handle_control_getconf(connection_t *conn, uint16_t body_len, const char *body)
/** Called when we get a SETEVENTS message: update conn->event_mask,
* and reply with DONE or ERROR. */
static int
handle_control_setevents(connection_t *conn, uint16_t len, const char *body)
handle_control_setevents(connection_t *conn, uint32_t len, const char *body)
{
uint16_t event_code;
uint32_t event_mask = 0;
@ -382,7 +406,7 @@ decode_hashed_password(char *buf, const char *hashed)
* OPEN. Reply with DONE or ERROR.
*/
static int
handle_control_authenticate(connection_t *conn, uint16_t len, const char *body)
handle_control_authenticate(connection_t *conn, uint32_t len, const char *body)
{
or_options_t *options = get_options();
if (options->CookieAuthentication) {
@ -421,7 +445,7 @@ handle_control_authenticate(connection_t *conn, uint16_t len, const char *body)
}
static int
handle_control_saveconf(connection_t *conn, uint16_t len,
handle_control_saveconf(connection_t *conn, uint32_t len,
const char *body)
{
if (save_current_config()<0) {
@ -434,7 +458,7 @@ handle_control_saveconf(connection_t *conn, uint16_t len,
}
static int
handle_control_signal(connection_t *conn, uint16_t len,
handle_control_signal(connection_t *conn, uint32_t len,
const char *body)
{
if (len != 1) {
@ -449,7 +473,7 @@ handle_control_signal(connection_t *conn, uint16_t len,
}
static int
handle_control_mapaddress(connection_t *conn, uint16_t len, const char *body)
handle_control_mapaddress(connection_t *conn, uint32_t len, const char *body)
{
smartlist_t *elts;
smartlist_t *lines;
@ -478,8 +502,9 @@ handle_control_mapaddress(connection_t *conn, uint16_t len, const char *body)
log_fn(LOG_WARN,
"Unable to allocate address for '%s' in AdressMap msg", line);
} else {
char *ans = tor_malloc(strlen(addr)+strlen(to)+2);
tor_snprintf(ans, "%s %s", addr, to);
size_t anslen = strlen(addr)+strlen(to)+2;
char *ans = tor_malloc(anslen);
tor_snprintf(ans, anslen, "%s %s", addr, to);
addressmap_register(addr, tor_strdup(to), 0);
smartlist_add(reply, ans);
}
@ -542,7 +567,7 @@ handle_getinfo_helper(const char *question)
}
static int
handle_control_getinfo(connection_t *conn, uint16_t len, const char *body)
handle_control_getinfo(connection_t *conn, uint32_t len, const char *body)
{
smartlist_t *questions = NULL;
smartlist_t *answers = NULL;
@ -574,7 +599,7 @@ handle_control_getinfo(connection_t *conn, uint16_t len, const char *body)
msg = smartlist_join_strings2(answers, "\0", 1, 1, &msg_len);
send_control_message(conn, CONTROL_CMD_INFOVALUE,
(uint16_t)msg_len, msg_len?msg:NULL);
msg_len, msg_len?msg:NULL);
done:
if (answers) SMARTLIST_FOREACH(answers, char *, cp, tor_free(cp));
@ -586,20 +611,20 @@ handle_control_getinfo(connection_t *conn, uint16_t len, const char *body)
return 0;
}
static int
handle_control_extendcircuit(connection_t *conn, uint16_t len,
handle_control_extendcircuit(connection_t *conn, uint32_t len,
const char *body)
{
send_control_error(conn,ERR_UNRECOGNIZED_TYPE,"not yet implemented");
return 0;
}
static int handle_control_attachstream(connection_t *conn, uint16_t len,
static int handle_control_attachstream(connection_t *conn, uint32_t len,
const char *body)
{
send_control_error(conn,ERR_UNRECOGNIZED_TYPE,"not yet implemented");
return 0;
}
static int
handle_control_postdescriptor(connection_t *conn, uint16_t len,
handle_control_postdescriptor(connection_t *conn, uint32_t len,
const char *body)
{
if (router_load_single_router(body)<0) {
@ -634,7 +659,8 @@ int connection_control_reached_eof(connection_t *conn) {
*/
int
connection_control_process_inbuf(connection_t *conn) {
uint16_t body_len, command_type;
uint32_t body_len;
uint16_t command_type;
char *body;
tor_assert(conn);
@ -726,6 +752,10 @@ connection_control_process_inbuf(connection_t *conn) {
send_control_error(conn, ERR_UNRECOGNIZED_TYPE,
"Command type only valid from server to tor client");
break;
case CONTROL_CMD_FRAGMENTHEADER:
case CONTROL_CMD_FRAGMENT:
log_fn(LOG_WARN, "Recieved command fragment out of order; ignoring.");
send_control_error(conn, ERR_SYNTAX, "Bad fragmentation on command.");
default:
log_fn(LOG_WARN, "Received unrecognized command type %d; ignoring.",
(int)command_type);
@ -756,7 +786,7 @@ control_event_circuit_status(circuit_t *circ, circuit_status_event_t tp)
set_uint32(msg+1, htonl(circ->global_identifier));
strlcpy(msg+5,path,path_len+1);
send_control_event(EVENT_CIRCUIT_STATUS, (uint16_t)(path_len+6), msg);
send_control_event(EVENT_CIRCUIT_STATUS, (uint32_t)(path_len+6), msg);
tor_free(path);
tor_free(msg);
return 0;
@ -784,7 +814,7 @@ control_event_stream_status(connection_t *conn, stream_status_event_t tp)
set_uint32(msg+1, htonl(conn->global_identifier));
strlcpy(msg+5, buf, len+1);
send_control_event(EVENT_STREAM_STATUS, (uint16_t)(5+len+1), msg);
send_control_event(EVENT_STREAM_STATUS, (uint32_t)(5+len+1), msg);
tor_free(msg);
return 0;
}
@ -805,7 +835,7 @@ control_event_or_conn_status(connection_t *conn,or_conn_status_event_t tp)
buf[0] = (uint8_t)tp;
strlcpy(buf+1,conn->nickname,sizeof(buf)-1);
len = strlen(buf+1);
send_control_event(EVENT_OR_CONN_STATUS, (uint16_t)(len+1), buf);
send_control_event(EVENT_OR_CONN_STATUS, (uint32_t)(len+1), buf);
return 0;
}
@ -837,7 +867,7 @@ control_event_logmsg(int severity, const char *msg)
return;
len = strlen(msg);
send_control_event(EVENT_WARNING, (uint16_t)(len+1), msg);
send_control_event(EVENT_WARNING, (uint32_t)(len+1), msg);
}
/** Choose a random authentication cookie and write it to disk.

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@ -1100,7 +1100,7 @@ int fetch_from_buf_http(buf_t *buf,
char **headers_out, size_t max_headerlen,
char **body_out, size_t *body_used, size_t max_bodylen);
int fetch_from_buf_socks(buf_t *buf, socks_request_t *req);
int fetch_from_buf_control(buf_t *buf, uint16_t *len_out, uint16_t *type_out,
int fetch_from_buf_control(buf_t *buf, uint32_t *len_out, uint16_t *type_out,
char **body_out);
void assert_buf_ok(buf_t *buf);