general cleanup and reabstraction, to prepare for tls

svn:r426
This commit is contained in:
Roger Dingledine 2003-09-05 06:04:03 +00:00
parent 99d1e4931b
commit 7a34cdf5ee
4 changed files with 171 additions and 253 deletions

View File

@ -92,6 +92,7 @@ connection_t *connection_new(int type) {
conn->timestamp_lastread = now.tv_sec;
conn->timestamp_lastwritten = now.tv_sec;
#ifndef TOR_TLS
if (connection_speaks_cells(conn)) {
conn->f_crypto = crypto_new_cipher_env(CONNECTION_CIPHER);
if (!conn->f_crypto) {
@ -105,6 +106,7 @@ connection_t *connection_new(int type) {
return NULL;
}
}
#endif
conn->done_sending = conn->done_receiving = 0;
return conn;
}
@ -120,10 +122,16 @@ void connection_free(connection_t *conn) {
free(conn->dest_addr);
if(connection_speaks_cells(conn)) {
directory_set_dirty();
#ifdef TOR_TLS
if (conn->SSL)
crypt_SSL_free(conn->SSL);
#else
if (conn->f_crypto)
crypto_free_cipher_env(conn->f_crypto);
if (conn->b_crypto)
crypto_free_cipher_env(conn->b_crypto);
#endif
}
if (conn->pkey)
@ -133,9 +141,6 @@ void connection_free(connection_t *conn) {
log_fn(LOG_INFO,"closing fd %d.",conn->s);
close(conn->s);
}
if(conn->type == CONN_TYPE_OR) {
directory_set_dirty();
}
free(conn);
}
@ -279,22 +284,52 @@ int retry_all_connections(uint16_t or_listenport, uint16_t ap_listenport, uint16
return 0;
}
int connection_handle_read(connection_t *conn) {
struct timeval now;
my_gettimeofday(&now);
conn->timestamp_lastread = now.tv_sec;
switch(conn->type) {
case CONN_TYPE_OR_LISTENER:
return connection_or_handle_listener_read(conn);
case CONN_TYPE_AP_LISTENER:
return connection_ap_handle_listener_read(conn);
case CONN_TYPE_DIR_LISTENER:
return connection_dir_handle_listener_read(conn);
default:
if(connection_read_to_buf(conn) < 0) {
if(conn->type == CONN_TYPE_DIR && conn->state == DIR_CONN_STATE_CONNECTING) {
/* it's a directory server and connecting failed: forget about this router */
/* XXX I suspect pollerr may make Windows not get to this point. :( */
router_forget_router(conn->addr,conn->port);
/* FIXME i don't think router_forget_router works. */
}
return -1;
}
if(connection_process_inbuf(conn) < 0) {
//log_fn(LOG_DEBUG,"connection_process_inbuf returned %d.",retval);
return -1;
}
if(!connection_state_is_open(conn) && conn->receiver_bucket == 0) {
log_fn(LOG_DEBUG,"receiver bucket reached 0 before handshake finished. Closing.");
return -1;
}
return 0;
} /* end switch */
}
int connection_read_to_buf(connection_t *conn) {
int read_result;
struct timeval now;
int at_most = global_read_bucket;
if(connection_speaks_cells(conn)) {
assert(conn->receiver_bucket >= 0);
}
if(!connection_speaks_cells(conn)) {
} else {
assert(conn->receiver_bucket < 0);
}
my_gettimeofday(&now);
conn->timestamp_lastread = now.tv_sec;
if(conn->receiver_bucket >= 0 && at_most > conn->receiver_bucket)
at_most = conn->receiver_bucket;
@ -338,13 +373,44 @@ int connection_outbuf_too_full(connection_t *conn) {
}
int connection_flush_buf(connection_t *conn) {
return flush_buf(conn->s, &conn->outbuf, &conn->outbuflen, &conn->outbuf_flushlen, &conn->outbuf_datalen);
return flush_buf(conn->s, &conn->outbuf, &conn->outbuflen,
&conn->outbuf_flushlen, &conn->outbuf_datalen);
}
int connection_handle_write(connection_t *conn) {
struct timeval now;
int retval;
if(connection_is_listener(conn)) {
log_fn(LOG_DEBUG,"Got a listener socket. Can't happen!");
return -1;
}
my_gettimeofday(&now);
conn->timestamp_lastwritten = now.tv_sec;
#ifdef TOR_TLS
if(connection_speaks_cells(conn)) {
retval = flush_buf_SSL(conn->SSL, &conn->outbuf, &conn->outbuflen,
&conn->outbuf_flushlen, &conn->outbuf_datalen);
...
} else
#endif
{
retval = flush_buf(conn->s, &conn->outbuf, &conn->outbuflen,
&conn->outbuf_flushlen, &conn->outbuf_datalen);
/* conns in CONNECTING state will fall through... */
if(retval == 0) { /* it's done flushing */
retval = connection_finished_flushing(conn); /* ...and get handled here. */
}
}
return retval;
}
int connection_write_to_buf(char *string, int len, connection_t *conn) {
struct timeval now;
my_gettimeofday(&now);
if(!len)
return 0;
@ -352,12 +418,10 @@ int connection_write_to_buf(char *string, int len, connection_t *conn) {
if(conn->marked_for_close)
return 0;
conn->timestamp_lastwritten = now.tv_sec;
if( (!connection_speaks_cells(conn)) ||
(!connection_state_is_open(conn)) ||
(options.LinkPadding == 0) ) {
/* connection types other than or and op, or or/op not in 'open' state, should flush immediately */
/* connection types other than or, or or not in 'open' state, should flush immediately */
/* also flush immediately if we're not doing LinkPadding, since otherwise it will never flush */
connection_start_writing(conn);
conn->outbuf_flushlen += len;
@ -397,78 +461,6 @@ int connection_state_is_open(connection_t *conn) {
return 0;
}
void connection_send_cell(connection_t *conn) {
cell_t cell;
int bytes_in_full_flushlen;
assert(0); /* this function has decayed. rewrite before using. */
/* this function only gets called if options.LinkPadding is 1 */
assert(options.LinkPadding == 1);
assert(conn);
if(!connection_speaks_cells(conn)) {
/* this conn doesn't speak cells. do nothing. */
return;
}
if(!connection_state_is_open(conn)) {
/* it's not in 'open' state, all data should already be waiting to be flushed */
assert(conn->outbuf_datalen == conn->outbuf_flushlen);
return;
}
#if 0 /* use to send evenly spaced cells, but not padding */
if(conn->outbuf_datalen - conn->outbuf_flushlen >= sizeof(cell_t)) {
conn->outbuf_flushlen += sizeof(cell_t); /* instruct it to send a cell */
connection_start_writing(conn);
}
#endif
connection_increment_send_timeval(conn); /* update when we'll send the next cell */
bytes_in_full_flushlen = conn->bandwidth / 100; /* 10ms worth */
if(bytes_in_full_flushlen < 10*sizeof(cell_t))
bytes_in_full_flushlen = 10*sizeof(cell_t); /* but at least 10 cells worth */
if(conn->outbuf_flushlen > bytes_in_full_flushlen - sizeof(cell_t)) {
/* if we would exceed bytes_in_full_flushlen by adding a new cell */
return;
}
if(conn->outbuf_datalen - conn->outbuf_flushlen < sizeof(cell_t)) {
/* we need to queue a padding cell first */
memset(&cell,0,sizeof(cell_t));
cell.command = CELL_PADDING;
connection_write_cell_to_buf(&cell, conn);
}
/* The connection_write_cell_to_buf() call doesn't increase the flushlen
* (if link padding is on). So if there isn't a whole cell waiting-but-
* not-yet-flushed, we add a padding cell. Thus in any case the gap between
* outbuf_datalen and outbuf_flushlen is at least sizeof(cell_t).
*/
conn->outbuf_flushlen += sizeof(cell_t); /* instruct it to send a cell */
connection_start_writing(conn);
}
void connection_increment_send_timeval(connection_t *conn) {
/* add "1000000 * sizeof(cell_t) / conn->bandwidth" microseconds to conn->send_timeval */
/* FIXME should perhaps use ceil() of this. For now I simply add 1. */
tv_addms(&conn->send_timeval, 1+1000 * sizeof(cell_t) / conn->bandwidth);
}
void connection_init_timeval(connection_t *conn) {
assert(conn);
my_gettimeofday(&conn->send_timeval);
connection_increment_send_timeval(conn);
}
int connection_send_destroy(aci_t aci, connection_t *conn) {
cell_t cell;

View File

@ -6,6 +6,7 @@
extern or_options_t options; /* command-line and config-file options */
#ifndef TOR_TLS
static int or_handshake_op_send_keys(connection_t *conn);
static int or_handshake_op_finished_sending_keys(connection_t *conn);
@ -15,8 +16,9 @@ static int or_handshake_client_send_auth(connection_t *conn);
static int or_handshake_server_process_auth(connection_t *conn);
static int or_handshake_server_process_nonce(connection_t *conn);
static void connection_or_set_open(connection_t *conn);
static void conn_or_init_crypto(connection_t *conn);
#endif
static void connection_or_set_open(connection_t *conn);
/*
*
@ -29,7 +31,6 @@ int connection_or_process_inbuf(connection_t *conn) {
assert(conn && conn->type == CONN_TYPE_OR);
if(conn->inbuf_reached_eof) {
/* eof reached, kill it. */
log_fn(LOG_DEBUG,"conn reached eof. Closing.");
return -1;
}
@ -37,12 +38,14 @@ int connection_or_process_inbuf(connection_t *conn) {
// log(LOG_DEBUG,"connection_or_process_inbuf(): state %d.",conn->state);
switch(conn->state) {
#ifndef TOR_TLS
case OR_CONN_STATE_CLIENT_AUTH_WAIT:
return or_handshake_client_process_auth(conn);
case OR_CONN_STATE_SERVER_AUTH_WAIT:
return or_handshake_server_process_auth(conn);
case OR_CONN_STATE_SERVER_NONCE_WAIT:
return or_handshake_server_process_nonce(conn);
#endif
case OR_CONN_STATE_OPEN:
return connection_process_cell_from_inbuf(conn);
default:
@ -583,7 +586,6 @@ or_handshake_server_process_auth(connection_t *conn) {
crypto_cipher_decrypt_init_cipher(conn->f_crypto);
conn->state = OR_CONN_STATE_OPEN;
connection_init_timeval(conn);
connection_watch_events(conn, POLLIN);
return connection_process_inbuf(conn); /* in case they sent some cells along with the keys */
@ -654,10 +656,10 @@ static void
connection_or_set_open(connection_t *conn) {
conn->state = OR_CONN_STATE_OPEN;
directory_set_dirty();
connection_init_timeval(conn);
connection_watch_events(conn, POLLIN);
}
#ifndef TOR_TLS
static void
conn_or_init_crypto(connection_t *conn) {
//int x;
@ -673,6 +675,7 @@ conn_or_init_crypto(connection_t *conn) {
crypto_cipher_decrypt_init_cipher(conn->b_crypto);
/* always encrypt with f, always decrypt with b */
}
#endif

View File

@ -244,83 +244,47 @@ void connection_start_writing(connection_t *conn) {
}
static void conn_read(int i) {
int retval;
connection_t *conn;
if(!(poll_array[i].revents & (POLLIN|POLLHUP|POLLERR)))
return; /* this conn doesn't want to read */
/* see http://www.greenend.org.uk/rjk/2001/06/poll.html for
* discussion of POLLIN vs POLLHUP */
conn = connection_array[i];
assert(conn);
//log_fn(LOG_DEBUG,"socket %d has something to read.",conn->s);
if(
/* XXX does POLLHUP also mean it's definitely broken? */
#ifdef MS_WINDOWS
if (poll_array[i].revents & POLLERR) {
retval = -1;
goto error;
}
(poll_array[i].revents & POLLERR) ||
#endif
if (conn->type == CONN_TYPE_OR_LISTENER) {
retval = connection_or_handle_listener_read(conn);
} else if (conn->type == CONN_TYPE_AP_LISTENER) {
retval = connection_ap_handle_listener_read(conn);
} else if (conn->type == CONN_TYPE_DIR_LISTENER) {
retval = connection_dir_handle_listener_read(conn);
} else {
retval = connection_read_to_buf(conn);
if (retval < 0 && conn->type == CONN_TYPE_DIR && conn->state == DIR_CONN_STATE_CONNECTING) {
/* it's a directory server and connecting failed: forget about this router */
router_forget_router(conn->addr,conn->port); /* FIXME i don't think this function works. */
}
if (retval >= 0) { /* all still well */
retval = connection_process_inbuf(conn);
// log_fn(LOG_DEBUG,"connection_process_inbuf returned %d.",retval);
if(retval >= 0 && !connection_state_is_open(conn) && conn->receiver_bucket == 0) {
log(LOG_DEBUG,"conn_read(): receiver bucket reached 0 before handshake finished. Closing.");
retval = -1;
}
}
}
#ifdef MS_WINDOWS
error:
#endif
if(retval < 0) { /* this connection is broken. remove it */
connection_handle_read(conn) < 0)
{
/* this connection is broken. remove it */
log_fn(LOG_INFO,"%s connection broken, removing.", conn_type_to_string[conn->type]);
connection_remove(conn);
connection_free(conn);
if(i<nfds) { /* we just replaced the one at i with a new one.
process it too. */
if(poll_array[i].revents & (POLLIN|POLLHUP|POLLERR))
/* something to read */
if(i<nfds) { /* we just replaced the one at i with a new one. process it too. */
conn_read(i);
}
}
}
static void conn_write(int i) {
int retval;
connection_t *conn;
if(!(poll_array[i].revents & POLLOUT))
return; /* this conn doesn't want to write */
conn = connection_array[i];
//log_fn(LOG_DEBUG,"socket %d wants to write.",conn->s);
if(connection_is_listener(conn)) {
log_fn(LOG_DEBUG,"Got a listener socket. Can't happen!");
retval = -1;
} else {
/* else it's an OP, OR, or exit */
retval = connection_flush_buf(conn); /* conns in CONNECTING state will fall through... */
if(retval == 0) { /* it's done flushing */
retval = connection_finished_flushing(conn); /* ...and get handled here. */
}
}
if(retval < 0) { /* this connection is broken. remove it. */
if(connection_handle_write(conn) < 0) { /* this connection is broken. remove it. */
log_fn(LOG_DEBUG,"%s connection broken, removing.", conn_type_to_string[conn->type]);
connection_remove(conn);
connection_free(conn);
if(i<nfds) { /* we just replaced the one at i with a new one.
process it too. */
if(poll_array[i].revents & POLLOUT) /* something to write */
if(i<nfds) { /* we just replaced the one at i with a new one. process it too. */
conn_write(i);
}
}
@ -346,7 +310,7 @@ static void check_conn_marked(int i) {
}
}
static int prepare_for_poll(int *timeout) {
static int prepare_for_poll(void) {
int i;
// connection_t *conn = NULL;
connection_t *tmpconn;
@ -434,45 +398,9 @@ static int prepare_for_poll(int *timeout) {
current_second = now.tv_sec; /* remember which second it is, for next time */
}
*timeout = 1000 - (now.tv_usec / 1000); /* how many milliseconds til the next second? */
return 0;
return (1000 - (now.tv_usec / 1000)); /* how many milliseconds til the next second? */
}
/* Link padding stuff left here for fun. Not used now. */
#if 0
if(options.LinkPadding) {
/* now check which conn wants to speak soonest */
for(i=0;i<nfds;i++) {
tmpconn = connection_array[i];
if(!connection_speaks_cells(tmpconn))
continue; /* this conn type doesn't send cells */
if(!connection_state_is_open(tmpconn))
continue; /* only conns in state 'open' have a valid send_timeval */
while(tv_cmp(&tmpconn->send_timeval,&now) <= 0) { /* send_timeval has already passed, let it send a cell */
connection_send_cell(tmpconn);
}
if(!conn || tv_cmp(&tmpconn->send_timeval, &soonest) < 0) { /* this is the best choice so far */
conn = tmpconn;
soonest.tv_sec = conn->send_timeval.tv_sec;
soonest.tv_usec = conn->send_timeval.tv_usec;
}
}
if(conn) { /* we might want to set *timeout sooner */
ms_until_conn = (soonest.tv_sec - now.tv_sec)*1000 +
(soonest.tv_usec - now.tv_usec)/1000;
// log(LOG_DEBUG,"prepare_for_poll(): conn %d times out in %d ms.",conn->s, ms_until_conn);
if(ms_until_conn < *timeout) { /* use the new one */
// log(LOG_DEBUG,"prepare_for_poll(): conn %d soonest, in %d ms.",conn->s,ms_until_conn);
*timeout = ms_until_conn;
}
}
}
#endif
static int do_main_loop(void) {
int i;
int timeout;
@ -516,7 +444,7 @@ static int do_main_loop(void) {
/* start up the necessary connections based on which ports are
* non-zero. This is where we try to connect to all the other ORs,
* and start the listeners
* and start the listeners.
*/
retry_all_connections((uint16_t) options.ORPort,
(uint16_t) options.APPort,
@ -543,17 +471,10 @@ static int do_main_loop(void) {
please_reap_children = 0;
}
#endif /* signal stuff */
if(prepare_for_poll(&timeout) < 0) {
log(LOG_DEBUG,"do_main_loop(): prepare_for_poll failed, exiting.");
return -1;
}
/* now timeout is the value we'll hand to poll. It's either -1, meaning
* don't timeout, else it indicates the soonest event (either the
* one-second rollover for refilling receiver buckets, or the soonest
* conn that needs to send a cell)
*/
/* poll until we have an event, or it's time to do something */
timeout = prepare_for_poll();
/* poll until we have an event, or the second ends */
poll_result = poll(poll_array, nfds, timeout);
#if 0 /* let catch() handle things like ^c, and otherwise don't worry about it */
@ -567,15 +488,10 @@ static int do_main_loop(void) {
if(poll_result > 0) { /* we have at least one connection to deal with */
/* do all the reads and errors first, so we can detect closed sockets */
for(i=0;i<nfds;i++)
if(poll_array[i].revents & (POLLIN|POLLHUP|POLLERR))
/* something to read, or an error. */
conn_read(i); /* this also blows away broken connections */
/* see http://www.greenend.org.uk/rjk/2001/06/poll.html for discussion
* of POLLIN vs POLLHUP */
/* then do the writes */
for(i=0;i<nfds;i++)
if(poll_array[i].revents & POLLOUT) /* something to write */
conn_write(i);
/* any of the conns need to be closed now? */

View File

@ -94,7 +94,7 @@
#include "../common/log.h"
#include "../common/util.h"
#define RECOMMENDED_SOFTWARE_VERSIONS "0.0.2pre6,0.0.2pre7"
#define RECOMMENDED_SOFTWARE_VERSIONS "0.0.2pre8"
#define MAXCONNECTIONS 1000 /* upper bound on max connections.
can be lowered by config file */
@ -131,6 +131,7 @@
#define CPUWORKER_TASK_ONION CPUWORKER_STATE_BUSY_ONION
#define CPUWORKER_TASK_HANDSHAKE CPUWORKER_STATE_BUSY_HANDSHAKE
#ifndef TOR_TLS
/* how to read these states:
* foo_CONN_STATE_bar_baz:
* "I am acting as a bar, currently in stage baz of talking with a foo."
@ -145,6 +146,11 @@
#define OR_CONN_STATE_SERVER_SENDING_AUTH 7 /* writing auth and nonce */
#define OR_CONN_STATE_SERVER_NONCE_WAIT 8 /* waiting for confirmation of nonce */
#define OR_CONN_STATE_OPEN 9 /* ready to send/receive cells. */
#else
#define OR_CONN_STATE_CONNECTING 0 /* waiting for connect() to finish */
#define OR_CONN_STATE_HANDSHAKING 1 /* SSL is handshaking, not done yet */
#define OR_CONN_STATE_OPEN 2 /* ready to send/receive cells. */
#endif
#define EXIT_CONN_STATE_RESOLVING 0 /* waiting for response from dns farm */
#define EXIT_CONN_STATE_CONNECTING 1 /* waiting for connect() to finish */
@ -272,73 +278,72 @@ typedef struct {
struct connection_t {
/* Used by all types: */
uint8_t type;
int state;
uint8_t wants_to_read;
uint8_t state;
uint8_t wants_to_read; /* should we start reading again once
* the bandwidth throttler allows it?
*/
int s; /* our socket */
int poll_index;
int marked_for_close;
int poll_index; /* index of this conn into the poll_array */
int marked_for_close; /* should we close this conn on the next
* iteration of the main loop?
*/
char *inbuf;
int inbuflen;
int inbuf_datalen;
int inbuf_reached_eof;
long timestamp_lastread;
int inbuflen; /* how many bytes are alloc'ed for inbuf? */
int inbuf_datalen; /* how many bytes of data are on inbuf? */
int inbuf_reached_eof; /* did read() return 0 on this conn? */
long timestamp_lastread; /* when was the last time poll() said we could read? */
char *outbuf;
int outbuflen; /* how many bytes are allocated for the outbuf? */
int outbuf_flushlen; /* how much data should we try to flush from the outbuf? */
int outbuf_datalen; /* how much data is there total on the outbuf? */
long timestamp_lastwritten;
long timestamp_lastwritten; /* when was the last time poll() said we could write? */
long timestamp_created;
long timestamp_created; /* when was this connection_t created? */
/* used by OR and OP: */
uint32_t bandwidth; /* connection bandwidth */
uint32_t bandwidth; /* connection bandwidth. Set to -1 for non-OR conns. */
int receiver_bucket; /* when this hits 0, stop receiving. Every second we
* add 'bandwidth' to this, capping it at 10*bandwidth.
* Set to -1 for non-OR conns.
*/
struct timeval send_timeval; /* for determining when to send the next cell */
uint32_t addr; /* these two uniquely identify a router. Both in host order. */
uint16_t port; /* if non-zero, they identify the guy on the other end
* of the connection. */
char *address; /* FQDN (or IP) of the guy on the other end.
* strdup into this, because free_connection frees it
*/
crypto_pk_env_t *pkey; /* public RSA key for the other side */
#ifndef TOR_TLS
/* Used only by OR connections: */
/* link encryption */
crypto_cipher_env_t *f_crypto;
crypto_cipher_env_t *b_crypto;
// struct timeval lastsend; /* time of last transmission to the client */
// struct timeval interval; /* transmission interval */
char nonce[8];
#endif
uint32_t addr; /* these two uniquely identify a router. Both in host order. */
uint16_t port;
/* used by exit and ap: */
/* Used only by edge connections: */
char stream_id[STREAM_ID_SIZE];
struct connection_t *next_stream;
struct connection_t *next_stream; /* points to the next stream at this edge, if any */
struct crypt_path_t *cpath_layer; /* a pointer to which node in the circ this conn exits at */
int package_window;
int deliver_window;
int done_sending;
int package_window; /* how many more relay cells can i send into the circuit? */
int deliver_window; /* how many more relay cells can end at me? */
int done_sending; /* for half-open connections; not used currently */
int done_receiving;
/* Used by ap: */
char socks_version;
char read_username;
/* Used by exit and ap: */
char *dest_addr;
/* Used only by AP connections: */
char socks_version; /* what socks version are they speaking at me? */
char read_username; /* have i read the username yet? */
char *dest_addr; /* what address and port are this stream's destination? */
uint16_t dest_port; /* host order */
/* Used by everyone */
char *address; /* strdup into this, because free_connection frees it */
/* Used for cell connections */
crypto_pk_env_t *pkey; /* public RSA key for the other side */
/* Used while negotiating OR/OR connections */
char nonce[8];
/* Used by worker connections */
/* Used only by worker connections: */
int num_processed; /* statistics kept by dns worker */
struct circuit_t *circ; /* by cpu worker to know who he's working for */
};
@ -392,7 +397,7 @@ struct crypt_path_t {
uint32_t addr;
uint16_t port;
char state;
uint8_t state;
#define CPATH_STATE_CLOSED 0
#define CPATH_STATE_AWAITING_KEYS 1
#define CPATH_STATE_OPEN 2
@ -429,9 +434,9 @@ struct circuit_t {
char onionskin[DH_ONIONSKIN_LEN]; /* for storage while onionskin pending */
long timestamp_created;
char dirty; /* whether this circuit has been used yet */
uint8_t dirty; /* whether this circuit has been used yet */
int state;
uint8_t state;
// unsigned char *onion; /* stores the onion when state is CONN_STATE_OPEN_WAIT */
// uint32_t onionlen; /* total onion length */
@ -612,6 +617,7 @@ int connection_handle_listener_read(connection_t *conn, int new_type, int new_st
/* start all connections that should be up but aren't */
int retry_all_connections(uint16_t or_listenport, uint16_t ap_listenport, uint16_t dir_listenport);
int connection_handle_read(connection_t *conn);
int connection_read_to_buf(connection_t *conn);
int connection_fetch_from_buf(char *string, int len, connection_t *conn);
@ -620,6 +626,7 @@ int connection_outbuf_too_full(connection_t *conn);
int connection_find_on_inbuf(char *string, int len, connection_t *conn);
int connection_wants_to_flush(connection_t *conn);
int connection_flush_buf(connection_t *conn);
int connection_handle_write(connection_t *conn);
int connection_write_to_buf(char *string, int len, connection_t *conn);
void connection_send_cell(connection_t *conn);