[tor-commits] [obfsproxy/master] Dump the silly get_other_conn() hack; use configurable circuits.
nickm at torproject.org
nickm at torproject.org
Fri Sep 9 17:08:59 UTC 2011
commit 3d85a235c6a6729eeac92413c2fcb982d4578a57
Author: George Kadianakis <desnacked at gmail.com>
Date: Sat Aug 20 16:28:13 2011 +0200
Dump the silly get_other_conn() hack; use configurable circuits.
* Introduce (*circuit_create) and (*circuit_free) which allow the module
writer to configure his circuits.
* Put the obfs2 state in a circuit instead of a connection.
---
src/network.c | 13 ++++++++--
src/protocol.c | 24 +++++++++++++++++++++
src/protocol.h | 12 ++++++++++
src/protocols/dummy.c | 19 ++++++++++++++++
src/protocols/dummy.h | 4 +++
src/protocols/obfs2.c | 51 +++++++++++++++++++++++++++-----------------
src/protocols/obfs2.h | 6 ++++-
src/test/unittest_obfs2.c | 51 ++++++++++++++++++++++++++++++++++----------
8 files changed, 144 insertions(+), 36 deletions(-)
diff --git a/src/network.c b/src/network.c
index 0fd5e4d..91b1237 100644
--- a/src/network.c
+++ b/src/network.c
@@ -378,7 +378,9 @@ circuit_create(conn_t *up, conn_t *down)
if (!up || !down)
return -1;
- circuit_t *r = xzalloc(sizeof(circuit_t));
+ obfs_assert(up->cfg == down->cfg);
+
+ circuit_t *r = proto_circuit_create(up->cfg);
r->upstream = up;
r->downstream = down;
up->circuit = r;
@@ -391,7 +393,7 @@ circuit_create_socks(conn_t *up)
{
obfs_assert(up);
- circuit_t *r = xzalloc(sizeof(circuit_t));
+ circuit_t *r = proto_circuit_create(up->cfg);
r->upstream = up;
r->socks_state = socks_state_new();
up->circuit = r;
@@ -410,6 +412,10 @@ circuit_add_down(circuit_t *circuit, conn_t *down)
static void
circuit_free(circuit_t *circuit)
{
+ /* keep the cfg so that we can use its vtable for proto_circuit_free() */
+ config_t *cfg = circuit->upstream->cfg;
+ obfs_assert(cfg);
+
/* break the circular references before deallocating each side */
circuit->upstream->circuit = NULL;
conn_free(circuit->upstream);
@@ -419,7 +425,8 @@ circuit_free(circuit_t *circuit)
}
if (circuit->socks_state)
socks_state_free(circuit->socks_state);
- free(circuit);
+
+ proto_circuit_free(circuit, cfg);
}
/**
diff --git a/src/protocol.c b/src/protocol.c
index 14437e6..81fd454 100644
--- a/src/protocol.c
+++ b/src/protocol.c
@@ -165,3 +165,27 @@ proto_conn_free(conn_t *conn) {
obfs_assert(conn->cfg->vtable->conn_free);
conn->cfg->vtable->conn_free(conn);
}
+
+/**
+ This protocol is called everytime a circuit has to be created.
+ Return a circuit_t on success or a NULL on fail.
+*/
+circuit_t *
+proto_circuit_create(config_t *cfg)
+{
+ obfs_assert(cfg);
+ obfs_assert(cfg->vtable);
+ obfs_assert(cfg->vtable->circuit_create);
+ return cfg->vtable->circuit_create(cfg);
+}
+
+/**
+ This function destroys 'circuit', using the vtable off 'cfg'.
+*/
+void
+proto_circuit_free(circuit_t *circuit, config_t *cfg) {
+ obfs_assert(cfg);
+ obfs_assert(cfg->vtable);
+ obfs_assert(cfg->vtable->circuit_free);
+ cfg->vtable->circuit_free(circuit);
+}
diff --git a/src/protocol.h b/src/protocol.h
index ede91f1..d360594 100644
--- a/src/protocol.h
+++ b/src/protocol.h
@@ -62,6 +62,12 @@ struct protocol_vtable
/** Destroy per-connection, protocol-specific state. */
void (*conn_free)(conn_t *state);
+ /** A 'circuit_t' needs to be created. */
+ circuit_t *(*circuit_create)(config_t *cfg);
+
+ /** Destroy a 'circuit_t'. */
+ void (*circuit_free)(circuit_t *circuit);
+
/** Perform a connection handshake. Not all protocols have a handshake. */
int (*handshake)(conn_t *state, struct evbuffer *buf);
@@ -92,6 +98,8 @@ struct protocol_vtable
name##_config_get_target_addr, \
name##_conn_create, \
name##_conn_free, \
+ name##_circuit_create, \
+ name##_circuit_free, \
name##_handshake, name##_send, name##_recv \
}
@@ -107,6 +115,10 @@ struct evutil_addrinfo *config_get_target_addr(config_t *cfg);
conn_t *proto_conn_create(config_t *cfg);
void proto_conn_free(conn_t *conn);
+circuit_t *proto_circuit_create(config_t *cfg);
+void proto_circuit_free(circuit_t *conn, config_t *cfg);
+
+
int proto_handshake(conn_t *conn, void *buf);
int proto_send(conn_t *conn, void *source, void *dest);
enum recv_ret proto_recv(conn_t *conn, void *source, void *dest);
diff --git a/src/protocols/dummy.c b/src/protocols/dummy.c
index 27e6340..21fd3ca 100644
--- a/src/protocols/dummy.c
+++ b/src/protocols/dummy.c
@@ -22,6 +22,12 @@ downcast_conn(conn_t *p)
return DOWNCAST(dummy_conn_t, super, p);
}
+static inline dummy_circuit_t *
+downcast_circuit(circuit_t *p)
+{
+ return DOWNCAST(dummy_circuit_t, super, p);
+}
+
/**
Helper: Parses 'options' and fills 'cfg'.
*/
@@ -174,6 +180,19 @@ dummy_conn_free(conn_t *proto)
free(downcast_conn(proto));
}
+static circuit_t *
+dummy_circuit_create(config_t *cfg)
+{
+ dummy_circuit_t *circuit = xzalloc(sizeof(dummy_circuit_t));
+ return &circuit->super;
+}
+
+static void
+dummy_circuit_free(circuit_t *circ)
+{
+ free(downcast_circuit(circ));
+}
+
/** Dummy has no handshake */
static int
dummy_handshake(conn_t *proto, struct evbuffer *buf)
diff --git a/src/protocols/dummy.h b/src/protocols/dummy.h
index d243f06..3dc1995 100644
--- a/src/protocols/dummy.h
+++ b/src/protocols/dummy.h
@@ -33,6 +33,10 @@ typedef struct dummy_conn_t {
conn_t super;
} dummy_conn_t;
+typedef struct dummy_circuit_t {
+ circuit_t super;
+} dummy_circuit_t;
+
#endif
#endif
diff --git a/src/protocols/obfs2.c b/src/protocols/obfs2.c
index 42a1c04..6e241c3 100644
--- a/src/protocols/obfs2.c
+++ b/src/protocols/obfs2.c
@@ -22,6 +22,13 @@ downcast_conn(conn_t *p)
return DOWNCAST(obfs2_conn_t, super, p);
}
+static inline obfs2_circuit_t *
+downcast_circuit(circuit_t *p)
+{
+ return DOWNCAST(obfs2_circuit_t, super, p);
+}
+
+
static int parse_and_set_options(int n_options,
const char *const *options,
obfs2_config_t *params);
@@ -44,20 +51,10 @@ shared_seed_nonzero(const uchar *seed)
return memcmp(seed, SHARED_ZERO_SEED, SHARED_SECRET_LENGTH) != 0;
}
-/**
- Stupid temporary function returning the other conn of a circuit.
- For example, if 'conn' is the downstream connection on a circuit,
- this function returns the upstream connection.
-*/
-static inline conn_t *
-get_other_conn(conn_t *conn)
+static inline obfs2_state_t *
+get_state_from_conn(conn_t *conn)
{
- if (conn->circuit->upstream == conn) {
- return conn->circuit->downstream;
- } else {
- obfs_assert(conn->circuit->downstream == conn);
- return conn->circuit->upstream;
- }
+ return downcast_circuit(conn->circuit)->state;
}
static void
@@ -246,7 +243,6 @@ obfs2_conn_create(config_t *cfg)
obfs2_conn_t *conn = xzalloc(sizeof(obfs2_conn_t));
conn->super.cfg = cfg;
conn->super.mode = downcast_config(cfg)->mode;
- conn->state = state_create(cfg);
return &conn->super;
}
@@ -254,10 +250,25 @@ obfs2_conn_create(config_t *cfg)
static void
obfs2_conn_free(conn_t *conn)
{
- obfs2_conn_t *obfs2_conn = downcast_conn(conn);
+ free(downcast_conn(conn));
+}
+
+static circuit_t *
+obfs2_circuit_create(config_t *cfg)
+{
+ obfs2_circuit_t *circuit = xzalloc(sizeof(obfs2_circuit_t));
+ circuit->state = state_create(cfg);
+
+ return &circuit->super;
+}
+
+static void
+obfs2_circuit_free(circuit_t *circuit)
+{
+ obfs2_circuit_t *obfs2_circuit = downcast_circuit(circuit);
- obfs2_destroy(obfs2_conn->state);
- free(obfs2_conn);
+ obfs2_destroy(obfs2_circuit->state);
+ free(obfs2_circuit);
}
/**
@@ -402,7 +413,7 @@ obfs2_destroy(obfs2_state_t *state)
static int
obfs2_handshake(conn_t *s, struct evbuffer *buf)
{
- obfs2_state_t *state = downcast_conn(s)->state;
+ obfs2_state_t *state = get_state_from_conn(s);
uint32_t magic = htonl(OBFUSCATE_MAGIC_VALUE), plength, send_plength;
uchar msg[OBFUSCATE_MAX_PADDING + OBFUSCATE_SEED_LENGTH + 8];
@@ -474,7 +485,7 @@ static int
obfs2_send(conn_t *s,
struct evbuffer *source, struct evbuffer *dest)
{
- obfs2_state_t *state = downcast_conn(get_other_conn(s))->state;
+ obfs2_state_t *state = get_state_from_conn(s);
if (state->send_crypto) {
/* First of all, send any data that we've been waiting to send. */
@@ -554,7 +565,7 @@ static enum recv_ret
obfs2_recv(conn_t *s, struct evbuffer *source,
struct evbuffer *dest)
{
- obfs2_state_t *state = downcast_conn(s)->state;
+ obfs2_state_t *state = get_state_from_conn(s);
if (state->state == ST_WAIT_FOR_KEY) {
/* We're waiting for the first OBFUSCATE_SEED_LENGTH+8 bytes to show up
diff --git a/src/protocols/obfs2.h b/src/protocols/obfs2.h
index a8fe2cc..fb07407 100644
--- a/src/protocols/obfs2.h
+++ b/src/protocols/obfs2.h
@@ -79,9 +79,13 @@ typedef struct obfs2_config_t {
typedef struct obfs2_conn_t {
conn_t super;
- obfs2_state_t *state;
} obfs2_conn_t;
+typedef struct obfs2_circuit_t {
+ circuit_t super;
+ obfs2_state_t *state;
+} obfs2_circuit_t;
+
#endif
#endif
diff --git a/src/test/unittest_obfs2.c b/src/test/unittest_obfs2.c
index 6e14b1e..7037788 100644
--- a/src/test/unittest_obfs2.c
+++ b/src/test/unittest_obfs2.c
@@ -21,6 +21,18 @@ downcast(conn_t *proto)
return DOWNCAST(obfs2_conn_t, super, proto);
}
+static inline obfs2_circuit_t *
+downcast_circuit(circuit_t *p)
+{
+ return DOWNCAST(obfs2_circuit_t, super, p);
+}
+
+static inline obfs2_state_t *
+get_state_from_conn(conn_t *conn)
+{
+ return downcast_circuit(conn->circuit)->state;
+}
+
static void
test_obfs2_option_parsing(void *unused)
{
@@ -81,7 +93,9 @@ struct test_obfs2_state
config_t *cfg_client;
config_t *cfg_server;
conn_t *conn_client;
+ conn_t *conn2_client; /* dummy conn to build a circuit */
conn_t *conn_server;
+ conn_t *conn2_server; /* dummy conn to build a circuit */
struct evbuffer *output_buffer;
struct evbuffer *dummy_buffer;
};
@@ -91,10 +105,17 @@ cleanup_obfs2_state(const struct testcase_t *unused, void *state)
{
struct test_obfs2_state *s = (struct test_obfs2_state *)state;
+ proto_circuit_free(s->conn_client->circuit, s->cfg_client);
if (s->conn_client)
proto_conn_free(s->conn_client);
+ if (s->conn2_client)
+ proto_conn_free(s->conn2_client);
+
+ proto_circuit_free(s->conn_server->circuit, s->cfg_server);
if (s->conn_server)
proto_conn_free(s->conn_server);
+ if (s->conn2_server)
+ proto_conn_free(s->conn2_server);
if (s->cfg_client)
config_free(s->cfg_client);
@@ -136,6 +157,15 @@ setup_obfs2_state(const struct testcase_t *unused)
s->conn_server = proto_conn_create(s->cfg_server);
tt_assert(s->conn_server);
+ s->conn2_client = proto_conn_create(s->cfg_client);
+ tt_assert(s->conn2_client);
+
+ s->conn2_server = proto_conn_create(s->cfg_server);
+ tt_assert(s->conn2_server);
+
+ tt_assert(!(circuit_create(s->conn_client, s->conn2_client)<0));
+ tt_assert(!(circuit_create(s->conn_server, s->conn2_server)<0));
+
s->output_buffer = evbuffer_new();
tt_assert(s->output_buffer);
@@ -156,8 +186,8 @@ static void
test_obfs2_handshake(void *state)
{
struct test_obfs2_state *s = (struct test_obfs2_state *)state;
- obfs2_state_t *client_state = downcast(s->conn_client)->state;
- obfs2_state_t *server_state = downcast(s->conn_server)->state;
+ obfs2_state_t *client_state = get_state_from_conn(s->conn_client);
+ obfs2_state_t *server_state = get_state_from_conn(s->conn_server);
/* We create a client handshake message and pass it to output_buffer */
tt_int_op(0, <=, proto_handshake(s->conn_client, s->output_buffer));
@@ -167,6 +197,7 @@ test_obfs2_handshake(void *state)
tt_assert(RECV_GOOD == proto_recv(s->conn_server, s->output_buffer,
s->dummy_buffer));
+
/* Now, we create the server's handshake and pass it to output_buffer */
tt_int_op(0, <=, proto_handshake(s->conn_server, s->output_buffer));
@@ -193,10 +224,6 @@ test_obfs2_transfer(void *state)
int n;
struct evbuffer_iovec v[2];
- /* evil trick to bypass get_other_conn() */
- circuit_create(s->conn_client, s->conn_client);
- circuit_create(s->conn_server, s->conn_server);
-
/* Handshake */
tt_int_op(0, <=, proto_handshake(s->conn_client, s->output_buffer));
tt_assert(RECV_GOOD == proto_recv(s->conn_server, s->output_buffer,
@@ -254,8 +281,8 @@ static void
test_obfs2_split_handshake(void *state)
{
struct test_obfs2_state *s = (struct test_obfs2_state *)state;
- obfs2_state_t *client_state = downcast(s->conn_client)->state;
- obfs2_state_t *server_state = downcast(s->conn_server)->state;
+ obfs2_state_t *client_state = get_state_from_conn(s->conn_client);
+ obfs2_state_t *server_state = get_state_from_conn(s->conn_server);
uint32_t magic = htonl(OBFUSCATE_MAGIC_VALUE);
uint32_t plength1, plength1_msg1, plength1_msg2, send_plength1;
@@ -372,8 +399,8 @@ static void
test_obfs2_wrong_handshake_magic(void *state)
{
struct test_obfs2_state *s = (struct test_obfs2_state *)state;
- obfs2_state_t *client_state = downcast(s->conn_client)->state;
- obfs2_state_t *server_state = downcast(s->conn_server)->state;
+ obfs2_state_t *client_state = get_state_from_conn(s->conn_client);
+ obfs2_state_t *server_state = get_state_from_conn(s->conn_server);
uint32_t wrong_magic = 0xD15EA5E;
@@ -411,8 +438,8 @@ static void
test_obfs2_wrong_handshake_plength(void *state)
{
struct test_obfs2_state *s = (struct test_obfs2_state *)state;
- obfs2_state_t *client_state = downcast(s->conn_client)->state;
- obfs2_state_t *server_state = downcast(s->conn_server)->state;
+ obfs2_state_t *client_state = get_state_from_conn(s->conn_client);
+ obfs2_state_t *server_state = get_state_from_conn(s->conn_server);
uchar msg[OBFUSCATE_MAX_PADDING + OBFUSCATE_SEED_LENGTH + 8 + 1];
uint32_t magic = htonl(OBFUSCATE_MAGIC_VALUE);
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