commit 46762842d8eb314b13a158e725c472da0e0d3601
Author: George Kadianakis <desnacked(a)gmail.com>
Date: Sat Jun 11 00:03:33 2011 +0200
Updated function documentation.
---
src/main.c | 2 +-
src/network.c | 46 ++++++++++++++++++++++---
src/protocol.c | 5 +--
src/protocols/dummy.c | 29 +++++++++++++--
src/protocols/obfs2.c | 3 ++
src/protocols/obfs2_crypt.c | 42 +++++++++++++++++++++++
src/socks.c | 79 +++++++++++++++++++++++++++++++-----------
src/util.c | 16 +++++++++
8 files changed, 188 insertions(+), 34 deletions(-)
diff --git a/src/main.c b/src/main.c
index ace9e8c..9399783 100644
--- a/src/main.c
+++ b/src/main.c
@@ -80,7 +80,7 @@ populate_options(char **options_string,
}
/**
- Returns 1 if 'name' is the nmae of a supported protocol, otherwise
+ Returns 1 if 'name' is the name of a supported protocol, otherwise
it returns 0.
*/
static int
diff --git a/src/network.c b/src/network.c
index e3c2fa0..a0ab6e9 100644
--- a/src/network.c
+++ b/src/network.c
@@ -36,10 +36,9 @@ static void input_event_cb(struct bufferevent *bev, short what, void *arg);
static void output_event_cb(struct bufferevent *bev, short what, void *arg);
/**
- This function sets up the protocol defined by 'options' and
- attempts to bind a new listener for it.
+ This function spawns a listener according to the 'proto_params'.
- Returns the listener on success, NULL on fail.
+ Returns the listener on success and NULL on fail.
*/
listener_t *
listener_new(struct event_base *base,
@@ -72,6 +71,9 @@ listener_new(struct event_base *base,
return lsn;
}
+/**
+ Deallocates listener_t 'lsn'.
+*/
void
listener_free(listener_t *lsn)
{
@@ -83,9 +85,16 @@ listener_free(listener_t *lsn)
free(lsn);
}
+/**
+ This function is called when a new connection is received.
+
+ It initializes the protocol we are using, sets up the necessary
+ callbacks for input/output and does the protocol handshake.
+*/
static void
simple_listener_cb(struct evconnlistener *evcl,
- evutil_socket_t fd, struct sockaddr *sourceaddr, int socklen, void *arg)
+ evutil_socket_t fd, struct sockaddr *sourceaddr,
+ int socklen, void *arg)
{
listener_t *lsn = arg;
struct event_base *base;
@@ -174,6 +183,9 @@ simple_listener_cb(struct evconnlistener *evcl,
evutil_closesocket(fd);
}
+/**
+ Deallocates conn_t 'conn'.
+*/
static void
conn_free(conn_t *conn)
{
@@ -189,6 +201,10 @@ conn_free(conn_t *conn)
free(conn);
}
+/**
+ Closes associated connection if the output evbuffer of 'bev' is
+ empty.
+*/
static void
close_conn_on_flush(struct bufferevent *bev, void *arg)
{
@@ -198,7 +214,9 @@ close_conn_on_flush(struct bufferevent *bev, void *arg)
conn_free(conn);
}
-/** This is only used in the input bufferevent of clients. */
+/**
+ This callback is responsible for handling SOCKS traffic.
+*/
static void
socks_read_cb(struct bufferevent *bev, void *arg)
{
@@ -253,6 +271,9 @@ socks_read_cb(struct bufferevent *bev, void *arg)
}
}
+/**
+ This callback is responsible for handling plaintext traffic.
+*/
static void
plaintext_read_cb(struct bufferevent *bev, void *arg)
{
@@ -267,6 +288,11 @@ plaintext_read_cb(struct bufferevent *bev, void *arg)
conn_free(conn);
}
+/**
+ This callback is responsible for handling obfusacted
+ traffic -- traffic that has already been obfuscated
+ by our protocol.
+*/
static void
obfuscated_read_cb(struct bufferevent *bev, void *arg)
{
@@ -288,6 +314,10 @@ obfuscated_read_cb(struct bufferevent *bev, void *arg)
bufferevent_get_output(conn->output));
}
+/**
+ Something broke in our connection or we reached EOF.
+ We prepare the connection to be closed ASAP.
+*/
static void
error_or_eof(conn_t *conn,
struct bufferevent *bev_err, struct bufferevent *bev_flush)
@@ -311,6 +341,9 @@ error_or_eof(conn_t *conn,
bufferevent_enable(bev_flush, EV_WRITE);
}
+/**
+ We land in here when an event happens on conn->input.
+*/
static void
input_event_cb(struct bufferevent *bev, short what, void *arg)
{
@@ -325,6 +358,9 @@ input_event_cb(struct bufferevent *bev, short what, void *arg)
/* XXX we don't expect any other events */
}
+/**
+ We land in here when an event happens on conn->output.
+*/
static void
output_event_cb(struct bufferevent *bev, short what, void *arg)
{
diff --git a/src/protocol.c b/src/protocol.c
index 544dcef..0845c11 100644
--- a/src/protocol.c
+++ b/src/protocol.c
@@ -40,9 +40,8 @@ set_up_protocol(int n_options, char **options,
}
/**
- This function creates a protocol object.
- It's called once per connection.
- It creates a new protocol_t structure and fills it's vtable etc.
+ This function is called once per connection and creates a protocol
+ object to be used during the session.
Return a 'protocol_t' if successful, NULL otherwise.
*/
struct protocol_t *
diff --git a/src/protocols/dummy.c b/src/protocols/dummy.c
index bdf97fc..be4c287 100644
--- a/src/protocols/dummy.c
+++ b/src/protocols/dummy.c
@@ -26,9 +26,10 @@ static int parse_and_set_options(int n_options, char **options,
struct protocol_params_t *params);
static protocol_vtable *vtable=NULL;
+
/**
- This function sets up the protocol and populates 'listner'
- according to 'options'.
+ This function populates 'params' according to 'options' and sets up
+ the protocol vtable.
'options' is an array like this:
{"dummy","socks","127.0.0.1:6666"}
@@ -56,6 +57,9 @@ dummy_init(int n_options, char **options,
return 1;
}
+/**
+ Helper: Parses 'options' and fills 'params'.
+*/
static int
parse_and_set_options(int n_options, char **options,
struct protocol_params_t *params)
@@ -96,6 +100,9 @@ parse_and_set_options(int n_options, char **options,
return 1;
}
+/**
+ Prints dummy protocol usage information.
+*/
static void
usage(void)
{
@@ -109,8 +116,12 @@ usage(void)
"\tobfsproxy dummy socks 127.0.0.1:5000\n");
}
-
-
+/*
+ This is called everytime we get a connection for the dummy
+ protocol.
+
+ It sets up the protocol vtable in 'proto_struct'.
+*/
void *
dummy_new(struct protocol_t *proto_struct,
struct protocol_params_t *params)
@@ -122,6 +133,11 @@ dummy_new(struct protocol_t *proto_struct,
return (void *)666U;
}
+/**
+ Responsible for sending data according to the dummy protocol.
+
+ The dummy protocol just puts the data of 'source' in 'dest'.
+*/
static int
dummy_send(void *nothing,
struct evbuffer *source, struct evbuffer *dest) {
@@ -130,6 +146,11 @@ dummy_send(void *nothing,
return evbuffer_add_buffer(dest,source);
}
+/*
+ Responsible for receiving data according to the dummy protocol.
+
+ The dummy protocol just puts the data of 'source' into 'dest'.
+*/
static enum recv_ret
dummy_recv(void *nothing,
struct evbuffer *source, struct evbuffer *dest) {
diff --git a/src/protocols/obfs2.c b/src/protocols/obfs2.c
index 676ddd7..f4302a2 100644
--- a/src/protocols/obfs2.c
+++ b/src/protocols/obfs2.c
@@ -61,6 +61,9 @@ obfs2_init(int n_options, char **options,
return 1;
}
+/**
+ Helper: Parses 'options' and fills 'params'.
+*/
int
parse_and_set_options(int n_options, char **options,
struct protocol_params_t *params)
diff --git a/src/protocols/obfs2_crypt.c b/src/protocols/obfs2_crypt.c
index 681fab6..4e814e7 100644
--- a/src/protocols/obfs2_crypt.c
+++ b/src/protocols/obfs2_crypt.c
@@ -48,6 +48,9 @@ get_uint32(const void *ptr)
#include "../sha256.c"
#endif
+/**
+ Initializes the obfs2 crypto subsystem.
+*/
int
initialize_crypto(void)
{
@@ -77,6 +80,9 @@ initialize_crypto(void)
#endif
}
+/**
+ Cleans up the obfs2 crypto subsystem.
+*/
void
cleanup_crypto(void)
{
@@ -91,18 +97,33 @@ cleanup_crypto(void)
struct digest_t {
SHA256_CTX ctx;
};
+
+/**
+ Returns a new SHA256 digest container, or NULL on failure.
+*/
digest_t *
digest_new(void)
{
digest_t *d = malloc(sizeof(digest_t));
+ if (!d)
+ return NULL;
SHA256_Init(&d->ctx);
return d;
}
+
+/**
+ Updates the contents of the SHA256 container 'd' with the first
+ 'len' bytes of 'buf'.
+*/
void
digest_update(digest_t *d, const uchar *buf, size_t len)
{
SHA256_Update(&d->ctx, buf, len);
}
+
+/**
+ Returns the digest stored in 'd' into 'buf' of length 'len'.
+*/
size_t
digest_getdigest(digest_t *d, uchar *buf, size_t len)
{
@@ -123,6 +144,8 @@ digest_t *
digest_new(void)
{
digest_t *d = malloc(sizeof(digest_t));
+ if (!d)
+ return NULL;
sha256_init(&d->ctx);
return d;
}
@@ -156,6 +179,9 @@ digest_free(digest_t *d)
Stream crypto
===== */
+/**
+ Initializes the AES cipher with 'key'.
+*/
crypt_t *
crypt_new(const uchar *key, size_t keylen)
{
@@ -171,12 +197,20 @@ crypt_new(const uchar *key, size_t keylen)
return k;
}
+
+/**
+ Sets the IV of 'key' to 'iv'.
+*/
void
crypt_set_iv(crypt_t *key, const uchar *iv, size_t ivlen)
{
assert(ivlen == sizeof(key->ivec));
memcpy(key->ivec, iv, ivlen);
}
+
+/*
+ In-place encrypts 'buf' with 'key'.
+*/
void
stream_crypt(crypt_t *key, uchar *buf, size_t len)
{
@@ -185,6 +219,10 @@ stream_crypt(crypt_t *key, uchar *buf, size_t len)
&key->key, key->ivec, key->ecount_buf,
&key->pos);
}
+
+/**
+ Deallocates memory space of 'key'.
+*/
void
crypt_free(crypt_t *key)
{
@@ -196,6 +234,10 @@ crypt_free(crypt_t *key)
PRNG
===== */
+/**
+ Fills 'buf' with 'buflen' random bytes and returns 0 on success.
+ Returns -1 on failure.
+*/
int
random_bytes(uchar *buf, size_t buflen)
{
diff --git a/src/socks.c b/src/socks.c
index 7cf179b..d3c69f2 100644
--- a/src/socks.c
+++ b/src/socks.c
@@ -48,6 +48,11 @@ static enum socks_ret socks5_do_negotiation(struct evbuffer *dest,
typedef unsigned char uchar;
+/**
+ Creates a new SOCKS state.
+
+ Returns a 'socks_state_t' on success, NULL on fail.
+*/
socks_state_t *
socks_state_new(void)
{
@@ -59,6 +64,9 @@ socks_state_new(void)
return state;
}
+/**
+ Deallocates memory of socks_state_t 's'.
+*/
void
socks_state_free(socks_state_t *s)
{
@@ -108,17 +116,15 @@ socks_errno_to_reply(socks_state_t *state, int error)
#undef ERR
/**
- Takes a command request from 'source', it evaluates it and if it's
- legit it parses it into 'parsereq'.
-
- It returns '1' if everything went fine.
- It returns '0' if we need more data from the client.
- It returns '-1' if we didn't like something.
- It returns '-2' if the client asked for something else than CONNECT.
- If that's the case we should send a reply back to the client
- telling him that we don't support it.
+ Takes a SOCKS5 command request from 'source', it evaluates it and
+ if it's legit it parses it into 'parsereq'.
- Disclaimer: This is just a temporary documentation.
+ It returns SOCKS_GOOD if everything went fine.
+ It returns SOCKS_INCOMPLETE if we need more data from the client.
+ It returns SOCKS_BROKEN if we didn't like something.
+ It returns SOCKS_CMD_NOT_CONNECT if the client asked for something
+ else other than CONNECT. If that's the case we should send a reply
+ back to the client telling him that we don't support it.
Client Request (Client -> Server)
*/
@@ -223,7 +229,8 @@ socks5_handle_request(struct evbuffer *source, struct parsereq *parsereq)
}
/**
- This sends the appropriate reply to the client on 'reply_dest'.
+ This sends the appropriate SOCKS5 reply to the client on
+ 'reply_dest', according to 'status'.
Server Reply (Server -> Client):
| version | rep | rsv | atyp | destaddr | destport
@@ -281,7 +288,7 @@ socks5_send_reply(struct evbuffer *reply_dest, socks_state_t *state,
/**
This function handles the initial SOCKS5 packet in 'source' sent by
- the client, which negotiates the version and method of SOCKS. If
+ the client which negotiates the version and method of SOCKS. If
the packet is actually valid, we reply to 'dest'.
Method Negotiation Packet (Client -> Server):
@@ -351,7 +358,14 @@ socks5_do_negotiation(struct evbuffer *dest, unsigned int neg_was_success)
return SOCKS_GOOD;
}
-/* rename to socks4_handle_request or something. */
+/**
+ Takes a SOCKS4/SOCKS4a command request from 'source', it evaluates
+ it and if it's legit it parses it into 'parsereq'.
+
+ It returns SOCKS_GOOD if everything went fine.
+ It returns SOCKS_INCOMPLETE if we need more data from the client.
+ It returns SOCKS_BROKEN if we didn't like something.
+*/
enum socks_ret
socks4_read_request(struct evbuffer *source, socks_state_t *state)
{
@@ -418,13 +432,18 @@ socks4_read_request(struct evbuffer *source, socks_state_t *state)
} else {
struct in_addr in;
in.s_addr = htonl(ipaddr);
- if (evutil_inet_ntop(AF_INET, &in, state->parsereq.addr, sizeof(state->parsereq.addr)) == NULL)
+ if (evutil_inet_ntop(AF_INET, &in, state->parsereq.addr,
+ sizeof(state->parsereq.addr)) == NULL)
return SOCKS_BROKEN;
}
return SOCKS_GOOD;
}
+/**
+ This sends the appropriate SOCKS4 reply to the client on
+ 'reply_dest', according to 'status'.
+*/
int
socks4_send_reply(struct evbuffer *dest, socks_state_t *state, int status)
{
@@ -448,12 +467,15 @@ socks4_send_reply(struct evbuffer *dest, socks_state_t *state, int status)
}
/**
- We are given data from the network.
- If we haven't negotiated with the connection, we try to negotiate.
- If we have already negotiated, we suppose it's a CONNECT request and
- try to be helpful.
-
- Returns 1 on done, -1 on unrecoverable error, 0 on "need more bytes
+ We are given SOCKS data from the network.
+ We figure out what what SOCKS version it is and act accordingly.
+
+ It returns SOCKS_GOOD if everything went fine.
+ It returns SOCKS_INCOMPLETE if we need more data from the client.
+ It returns SOCKS_BROKEN if we didn't like something.
+ It returns SOCKS_CMD_NOT_CONNECT if the client asked for something
+ else other than CONNECT. If that's the case we should send a reply
+ back to the client telling him that we don't support it.
*/
enum socks_ret
handle_socks(struct evbuffer *source, struct evbuffer *dest,
@@ -533,12 +555,22 @@ handle_socks(struct evbuffer *source, struct evbuffer *dest,
return SOCKS_BROKEN;
}
+/**
+ Returns the protocol status of the SOCKS state 'state'.
+*/
enum socks_status_t
socks_state_get_status(const socks_state_t *state)
{
return state->state;
}
+/**
+ If we have previously parsed a SOCKS CONNECT request, this function
+ places the corresponding address/port to 'af_out', 'addr_out' and
+ 'port_out'.
+
+ It returns 0 on success and -1 if it was called unnecessarily.
+*/
int
socks_state_get_address(const socks_state_t *state,
int *af_out,
@@ -553,6 +585,10 @@ socks_state_get_address(const socks_state_t *state,
return 0;
}
+/**
+ Places the address/port in 'sa' into the SOCKS state 'state' for
+ later retrieval.
+*/
int
socks_state_set_address(socks_state_t *state, const struct sockaddr *sa)
{
@@ -583,11 +619,12 @@ socks_state_set_address(socks_state_t *state, const struct sockaddr *sa)
/**
This function sends a SOCKS{5,4} "Server Reply" to 'dest'.
+
'error' is 0 if no errors were encountered during the SOCKS
operation (normally a CONNECT with no errors means that the
connect() was successful).
If 'error' is not 0, it means that an error was encountered and
- error carries the errno(3) of the error.
+ error carries the errno(3).
*/
int
socks_send_reply(socks_state_t *state, struct evbuffer *dest, int error)
diff --git a/src/util.c b/src/util.c
index d4eddb6..1d44a52 100644
--- a/src/util.c
+++ b/src/util.c
@@ -27,6 +27,17 @@ static void logv(int severity, const char *format, va_list ap);
/************************ Obfsproxy Network Routines *************************/
+/**
+ Accepts a string 'address' of the form ADDRESS:PORT and attempts to
+ parse it into 'addr_out' and put it's length into 'addrlen_out'.
+
+ If 'nodns' is set it means that 'address' was an IP address.
+ If 'passive' is set it means that the address is destined for
+ listening and not for connecting.
+
+ If no port was given in 'address', we set 'default_port' as the
+ port.
+*/
int
resolve_address_port(const char *address,
int nodns, int passive,
@@ -369,6 +380,10 @@ logv(int severity, const char *format, va_list ap)
}
#ifdef NEED_LOG_WRAPPERS
+/**
+ If our platform doesn't support the log_* macros defined in
+ util.h, we use these functions.
+*/
void
log_info(const char *format, ...)
{
@@ -399,4 +414,5 @@ log_debug(const char *format, ...)
va_end(ap);
}
+
#endif
