commit 83648b9054337c6276077a342c7d7653a9daafca Author: Zack Weinberg zackw@cmu.edu Date: Mon Jul 16 15:04:12 2012 -0700

Don't allow connection count to grow without limit in HTTP steg.

The fix involves two complementary changes: (1) restore the upper limit of 64 outstanding downstream connections per circuit; (2) HTTP steg needs to call ->cease_transmission() and ->expect_close() on its connections at the right times (for now, unconditionally; in the future, paying attention to the HTTP "Connection:" header). --- src/protocol/chop.cc | 3 ++- src/steg/http.cc | 13 ++++++++++++- src/steg/jsSteg.cc | 2 -- src/steg/pdfSteg.cc | 2 -- src/steg/swfSteg.cc | 3 --- 5 files changed, 14 insertions(+), 9 deletions(-)

diff --git a/src/protocol/chop.cc b/src/protocol/chop.cc index bb4a95c..3059c1b 100644 --- a/src/protocol/chop.cc +++ b/src/protocol/chop.cc @@ -479,7 +479,8 @@ chop_circuit_t::send() // reopening new connections. If we're the server, we have to // just twiddle our thumbs and hope the client does that. if (no_target_connection) { - if (config->mode != LSN_SIMPLE_SERVER) + if (config->mode != LSN_SIMPLE_SERVER && + downstreams.size() < 64) circuit_reopen_downstreams(this); else circuit_arm_axe_timer(this, axe_interval()); diff --git a/src/steg/http.cc b/src/steg/http.cc index 7caf2e7..381258c 100644 --- a/src/steg/http.cc +++ b/src/steg/http.cc @@ -588,7 +588,13 @@ http_steg_t::transmit(struct evbuffer *source) break; }

- if (rval == 0) have_transmitted = 1; + if (rval == 0) { + have_transmitted = 1; + // FIXME: should decide whether or not to do this based on the + // Connection: header. (Needs additional changes elsewhere, esp. + // in transmit_room.) + conn->cease_transmission(); + } return rval; } } @@ -671,6 +677,11 @@ http_server_receive(http_steg_t *s, conn_t *conn, struct evbuffer *dest, struct s->have_received = 1; s->type = type;

+ // FIXME: should decide whether or not to do this based on the + // Connection: header. (Needs additional changes elsewhere, esp. + // in transmit_room.) + conn->expect_close(); + conn->transmit_soon(100); return RECV_GOOD; } diff --git a/src/steg/jsSteg.cc b/src/steg/jsSteg.cc index dbe4431..3954829 100644 --- a/src/steg/jsSteg.cc +++ b/src/steg/jsSteg.cc @@ -893,8 +893,6 @@ http_server_JS_transmit (payloads& pl, struct evbuffer *source, conn_t *conn, evbuffer_drain(source, sbuflen);

free(outbuf2); - conn->cease_transmission(); - // downcast_steg(s)->have_transmitted = 1; return 0; }

diff --git a/src/steg/pdfSteg.cc b/src/steg/pdfSteg.cc index f76da99..8bff423 100644 --- a/src/steg/pdfSteg.cc +++ b/src/steg/pdfSteg.cc @@ -464,8 +464,6 @@ http_server_PDF_transmit(payloads &pl, struct evbuffer *source, }

evbuffer_drain(source, sbuflen); - - conn->cease_transmission(); return 0; }

diff --git a/src/steg/swfSteg.cc b/src/steg/swfSteg.cc index 8fb29ee..8e12d21 100644 --- a/src/steg/swfSteg.cc +++ b/src/steg/swfSteg.cc @@ -152,9 +152,6 @@ http_server_SWF_transmit(payloads& pl, struct evbuffer *source, conn_t *conn) return -1; }

- - conn->cease_transmission(); - free(inbuf); free(outbuf); return 0;