commit 7d121a79b8acbaf1f42807266bac91da1774edd0 Author: Zack Weinberg zackw@panix.com Date: Thu Mar 29 18:54:28 2012 -0700

Make 'embed' testable with test_tl (removing globals).

It still doesn't *work*, but now we have a chance of pinning down why. One bug flushed out of chop.cc already. --- Makefile.am | 1 + src/audit-globals.sh | 3 - src/protocol/chop.cc | 4 +- src/steg/embed.cc | 101 ++++++++++++++++++++++--------------------------- src/test/test_tl.py | 10 ++++- 5 files changed, 57 insertions(+), 62 deletions(-)

diff --git a/Makefile.am b/Makefile.am index 377e37f..6ba1b51 100644 --- a/Makefile.am +++ b/Makefile.am @@ -131,6 +131,7 @@ check-local: $(AM_V_at) ./unittests if INTEGRATION_TESTS @echo --- Integration tests --- + [ -e traces ] || ln -s $(srcdir)/traces . $(AM_V_at) $(PYTHON) -m unittest discover -s $(srcdir)/src/test -p 'test_*.py' -v else @echo !!! Integration tests skipped !!! diff --git a/src/audit-globals.sh b/src/audit-globals.sh index 99739b3..1768640 100644 --- a/src/audit-globals.sh +++ b/src/audit-globals.sh @@ -46,9 +46,6 @@ sed ' /^crypt init_crypto()::initialized$/d

# These are grandfathered; they need to be removed. - /^steg/embed embed_init$/d - /^steg/embed embed_num_traces$/d - /^steg/embed embed_traces$/d /^steg/http has_peer_name$/d /^steg/http peername$/d /^steg/payloads payload_count$/d diff --git a/src/protocol/chop.cc b/src/protocol/chop.cc index 06346b7..27e03ab 100644 --- a/src/protocol/chop.cc +++ b/src/protocol/chop.cc @@ -771,7 +771,9 @@ chop_circuit_t::send_targeted(chop_conn_t *conn, size_t blocksize) size_t avail = evbuffer_get_length(xmit_pending); opcode_t op = op_DAT;

- if (avail > SECTION_LEN) + if (avail > blocksize - MIN_BLOCK_SIZE) + avail = blocksize - MIN_BLOCK_SIZE; + else if (avail > SECTION_LEN) avail = SECTION_LEN; else if (upstream_eof && !sent_fin) // this block will carry the last byte of real data to be sent in diff --git a/src/steg/embed.cc b/src/steg/embed.cc index 6559bf7..f24c210 100644 --- a/src/steg/embed.cc +++ b/src/steg/embed.cc @@ -4,32 +4,34 @@ #include "steg.h" #include "rng.h"

+#include <errno.h> #include <event2/buffer.h> -#include <event2/event.h> -#include <stdio.h> -#include <unistd.h> -#include <time.h> +#include <vector> + +using std::vector;

namespace { struct trace_t { - int num_pkt; // number of packets in trace - short *pkt_sizes; // packet sizes (positive = client->server) - int *pkt_times; // packet inter-arrival times + vector<short> pkt_sizes; // packet sizes (positive = client->server) + vector<int> pkt_times; // packet inter-arrival times };

struct embed_steg_config_t : steg_config_t { bool is_clientside; + vector<trace_t> traces;

STEG_CONFIG_DECLARE_METHODS(embed); + + size_t get_random_trace() const; };

struct embed_steg_t : steg_t { embed_steg_config_t *config; conn_t *conn;

- int cur_idx; // current trace index + int cur_idx; // current trace index trace_t *cur; // current trace - int cur_pkt; // current packet in the trace + int cur_pkt; // current packet in the trace struct timeval last_pkt; // time at which last packet was sent/received

embed_steg_t(embed_steg_config_t *cf, conn_t *cn); @@ -46,10 +48,6 @@ namespace {

STEG_DEFINE_MODULE(embed);

-static int embed_init = 0; // whether traces are initialized -static int embed_num_traces; // number of traces -static trace_t *embed_traces; // global array of all traces - static int millis_since(struct timeval *last) { @@ -66,6 +64,32 @@ embed_steg_config_t::embed_steg_config_t(config_t *cfg) : steg_config_t(cfg), is_clientside(cfg->mode != LSN_SIMPLE_SERVER) { + // read in traces to use for connections + FILE *trace_file = fopen("traces/embed.txt", "r"); + if (!trace_file) + log_abort("opening traces/embed.txt: %s", strerror(errno)); + + int num_traces; + if (fscanf(trace_file, "%d", &num_traces) < 1) + log_abort("couldn't read number of traces"); + + traces.resize(num_traces); + + for (vector<trace_t>::iterator p = traces.begin(); p != traces.end(); ++p) { + int num_pkt; + if (fscanf(trace_file, "%d", &num_pkt) < 1) + log_abort("couldn't read number of packets in trace %ld", + p - traces.begin()); + + p->pkt_sizes.resize(num_pkt); + p->pkt_times.resize(num_pkt); + for (int i = 0; i < num_pkt; i++) + if (fscanf(trace_file, "%hd %d", &p->pkt_sizes[i], &p->pkt_times[i]) < 1) + log_abort("couldn't read trace entry %ld/%d", + p - traces.begin(), i); + } + + log_debug("read %d traces", num_traces); }

embed_steg_config_t::~embed_steg_config_t() @@ -78,50 +102,17 @@ embed_steg_config_t::steg_create(conn_t *conn) return new embed_steg_t(this, conn); }

-static void -init_embed_traces() -{ - // read in traces to use for connections - FILE *trace_file = fopen("traces/embed.txt", "r"); - if (fscanf(trace_file, "%d", &embed_num_traces) < 1) { - log_abort("couldn't read number of traces to use -- exiting"); - exit(1); - } - embed_traces = (trace_t *)xmalloc(sizeof(trace_t) * embed_num_traces); - for (int i = 0; i < embed_num_traces; i++) { - int num_pkt; - if (fscanf(trace_file, "%d", &num_pkt) < 1) { - log_abort("couldn't read number of packets to use -- exiting"); - exit(1); - } - embed_traces[i].num_pkt = num_pkt; - embed_traces[i].pkt_sizes = (short *)xmalloc(sizeof(short) * num_pkt); - embed_traces[i].pkt_times = (int *)xmalloc(sizeof(int) * num_pkt); - for (int j = 0; j < embed_traces[i].num_pkt; j++) { - if (fscanf(trace_file, "%hd %d", - &embed_traces[i].pkt_sizes[j], - &embed_traces[i].pkt_times[j]) < 1) { - log_abort("couldn't read numbers of packet size and times to use -- exiting"); - exit(1); - } - } - } - log_debug("read %d traces to use", embed_num_traces); - - embed_init = 1; -} - -static int -get_random_trace() +size_t +embed_steg_config_t::get_random_trace() const { - return rng_int(embed_num_traces); + return rng_int(traces.size()); }

bool embed_steg_t::advance_packet() { cur_pkt++; - return cur_pkt == cur->num_pkt; + return cur_pkt == int(cur->pkt_sizes.size()); }

short @@ -146,18 +137,16 @@ bool embed_steg_t::is_finished() { if (cur_idx == -1) return true; - return cur_pkt >= cur->num_pkt; + return cur_pkt >= int(cur->pkt_sizes.size()); }

embed_steg_t::embed_steg_t(embed_steg_config_t *cf, conn_t *cn) : config(cf), conn(cn) { - if (!embed_init) init_embed_traces(); - cur_idx = -1; if (config->is_clientside) { - cur_idx = get_random_trace(); - cur = &embed_traces[cur_idx]; + cur_idx = config->get_random_trace(); + cur = &config->traces[cur_idx]; cur_pkt = 0; } gettimeofday(&last_pkt, NULL); @@ -243,7 +232,7 @@ embed_steg_t::receive(struct evbuffer *dest) // if we are receiving the first packet of the trace, read the index if (cur_idx == -1) { if (evbuffer_remove(source, &cur_idx, 4) != 4) return -1; - cur = &embed_traces[cur_idx]; + cur = &config->traces[cur_idx]; cur_pkt = 0; pkt_size += 4;

diff --git a/src/test/test_tl.py b/src/test/test_tl.py index 6d632f8..9987c7d 100644 --- a/src/test/test_tl.py +++ b/src/test/test_tl.py @@ -78,8 +78,14 @@ class TimelineTest(object): "127.0.0.1:5010","nosteg_rr","127.0.0.1:5011","nosteg_rr", ))

- # NOTE: 'embed' steg presently cannot be tested using this system - # because it runs out of trace data before any of the tests complete. + # buggy, disabled + #def test_embed(self): + # self.doTest("chop", + # ("chop", "server", "127.0.0.1:5001", + # "127.0.0.1:5010","embed", + # "chop", "client", "127.0.0.1:4999", + # "127.0.0.1:5010","embed", + # ))

# NOTE: 'http' steg presently cannot be tested using this system # because the trace pools are process-global rather than per-listener.