From 275c99f9960314860f13b59f718af2f506196970 Mon Sep 17 00:00:00 2001 From: pepeto Date: Sat, 16 Feb 2013 18:09:38 +0100 Subject: [PATCH] Make initial network protocol compatible with old versions. --- common/connection.c | 1 + common/connection.h | 6 ++++ common/generate_packets.py | 12 +++---- common/packets.c | 85 ++++++++++++++++++++++++++++++++------------ common/packets.def | 15 ++++++-- common/packets.h | 46 ++++++++++++------------ doc/HACKING | 10 +++++- server/connecthand.c | 14 ++++++++ server/sernet.c | 13 +++++-- 9 files changed, 145 insertions(+), 57 deletions(-) diff --git a/common/connection.c b/common/connection.c index ff671b6..295542b 100644 --- a/common/connection.c +++ b/common/connection.c @@ -584,6 +584,7 @@ void connection_common_init(struct connection *pconn) { pconn->established = FALSE; pconn->used = TRUE; + packet_header_init(&pconn->packet_header); pconn->closing_reason = NULL; pconn->last_write = NULL; pconn->buffer = new_socket_packet_buffer(); diff --git a/common/connection.h b/common/connection.h index 7109403..b5ea5b7 100644 --- a/common/connection.h +++ b/common/connection.h @@ -115,6 +115,11 @@ struct socket_packet_buffer { unsigned char *data; }; +struct packet_header { + unsigned int length : 4; /* Actually 'enum data_type' */ + unsigned int type : 4; /* Actually 'enum data_type' */ +}; + #define SPECVEC_TAG byte #define SPECVEC_TYPE unsigned char #include "specvec.h" @@ -128,6 +133,7 @@ struct connection { int sock; bool used; bool established; /* have negotiated initial packets */ + struct packet_header packet_header; char *closing_reason; /* connection is "observer", not controller; may be observing diff --git a/common/generate_packets.py b/common/generate_packets.py index bb737a5..f2d8a71 100755 --- a/common/generate_packets.py +++ b/common/generate_packets.py @@ -653,7 +653,7 @@ class Variant: self.extra_send_args2=self.extra_send_args2+', force_to_send' self.extra_send_args3=self.extra_send_args3+', bool force_to_send' - self.receive_prototype='static struct %(packet_name)s *receive_%(name)s(struct connection *pc, enum packet_type type)'%self.__dict__ + self.receive_prototype='static struct %(packet_name)s *receive_%(name)s(struct connection *pc)'%self.__dict__ self.send_prototype='static int send_%(name)s(struct connection *pc%(extra_send_args)s)'%self.__dict__ # See Field.get_dict @@ -763,7 +763,7 @@ static char *stats_%(name)s_names[] = {%(names)s}; temp='''%(send_prototype)s { SEND_PACKET_START(%(type)s); - SEND_PACKET_END; + SEND_PACKET_END(%(type)s); } ''' @@ -919,7 +919,7 @@ static char *stats_%(name)s_names[] = {%(names)s}; if self.delta: delta_header=''' %(name)s_fields fields; struct %(packet_name)s *old; - struct genhash **hash = pc->phs.received + type; + struct genhash **hash = pc->phs.received + %(type)s; ''' delta_body1="\n DIO_BV_GET(&din, fields);\n" body1="" @@ -1138,7 +1138,7 @@ class Packet: self.extra_send_args2=self.extra_send_args2+', force_to_send' self.extra_send_args3=self.extra_send_args3+', bool force_to_send' - self.receive_prototype='struct %(name)s *receive_%(name)s(struct connection *pc, enum packet_type type)'%self.__dict__ + self.receive_prototype='struct %(name)s *receive_%(name)s(struct connection *pc)'%self.__dict__ self.send_prototype='int send_%(name)s(struct connection *pc%(extra_send_args)s)'%self.__dict__ if self.want_lsend: self.lsend_prototype='void lsend_%(name)s(struct conn_list *dest%(extra_send_args)s)'%self.__dict__ @@ -1273,7 +1273,7 @@ class Packet: no=v.no result=result+''' case %(no)s: - return receive_%(name2)s(pc, type);'''%self.get_dict(vars()) + return receive_%(name2)s(pc);'''%self.get_dict(vars()) result=result+''' default: log_debug("Unknown %(type)s variant for connection %%s", conn_description(pc)); @@ -1434,7 +1434,7 @@ def get_get_packet_helper(packets): ''' body="" for p in packets: - body=body+" case %(type)s:\n return receive_%(name)s(pc, type);\n\n"%p.__dict__ + body=body+" case %(type)s:\n return receive_%(name)s(pc);\n\n"%p.__dict__ extro=''' default: log_packet("unknown packet type %d received from %s", type, conn_description(pc)); diff --git a/common/packets.c b/common/packets.c index 309713f..19ba9f0 100644 --- a/common/packets.c +++ b/common/packets.c @@ -172,11 +172,12 @@ bool conn_compression_thaw(struct connection *pconn) /************************************************************************** It returns the request id of the outgoing packet (or 0 if is_server()). **************************************************************************/ -int send_packet_data(struct connection *pc, unsigned char *data, int len) +int send_packet_data(struct connection *pc, unsigned char *data, int len, + enum packet_type packet_type) { /* default for the server */ int result = 0; - int packet_type = ntohs((data[3] << 8) + data[2]); + log_packet("sending packet type=%s(%d) len=%d to %s", packet_name(packet_type), packet_type, len, @@ -329,12 +330,11 @@ void *get_packet_from_connection(struct connection *pc, enum packet_type type; int itype; } utype; - int typeb1, typeb2; struct data_in din; #ifdef USE_COMPRESSION bool compressed_packet = FALSE; + int header_size = 0; #endif - int header_size = 4; void *data; if (!pc->used) { @@ -347,7 +347,7 @@ void *get_packet_from_connection(struct connection *pc, } dio_input_init(&din, pc->buffer->data, pc->buffer->ndata); - dio_get_uint16(&din, &len_read); + dio_get_type(&din, pc->packet_header.length, &len_read); /* The non-compressed case */ whole_packet_len = len_read; @@ -377,6 +377,7 @@ void *get_packet_from_connection(struct connection *pc, return NULL; /* not all data has been read */ } +#ifdef USE_COMPRESSION if (whole_packet_len < header_size) { log_verbose("The packet size is reported to be less than header alone. " "The connection will be closed now."); @@ -385,7 +386,6 @@ void *get_packet_from_connection(struct connection *pc, return NULL; } -#ifdef USE_COMPRESSION if (compressed_packet) { uLong compressed_size = whole_packet_len - header_size; /* @@ -444,27 +444,17 @@ void *get_packet_from_connection(struct connection *pc, /* * At this point the packet is a plain uncompressed one. These have - * to have to be at least 4 bytes in size. + * to have to be at least the header bytes in size. */ - if (whole_packet_len < 2+2) { + if (whole_packet_len < (data_type_size(pc->packet_header.length) + + data_type_size(pc->packet_header.type))) { log_verbose("The packet stream is corrupt. The connection " "will be closed now."); connection_close(pc, _("decoding error")); return NULL; } - /* Instead of one dio_get_uint16() we do twice dio_get_uint8(). - * Older (<= 2.4) versions had 8bit type field, and we detect - * here if this is initial PACKET_SERVER_JOIN_REQ from such a client. */ - dio_get_uint8(&din, &typeb1); - - if (typeb1 == PACKET_SERVER_JOIN_REQ) { - utype.itype = typeb1; - } else { - dio_get_uint8(&din, &typeb2); - utype.itype = ntohs((typeb2 << 8) + typeb1); - } - + dio_get_type(&din, pc->packet_header.type, &utype.itype); utype.type = utype.itype; log_packet("got packet type=(%s)%d len=%d from %s", @@ -546,6 +536,57 @@ void remove_packet_from_buffer(struct socket_packet_buffer *buffer) len, buffer->ndata); } +/**************************************************************************** + Set the packet header field lengths used for the login protocol, + before the capability of the connection could be checked. + + NB: These values cannot be changed for backward compatibility reasons. +****************************************************************************/ +inline void packet_header_init(struct packet_header *packet_header) +{ + packet_header->length = DIOT_UINT16; + packet_header->type = DIOT_UINT8; +} + +/**************************************************************************** + Set the packet header field lengths used after the login protocol, + after the capability of the connection could be checked. +****************************************************************************/ +static inline void packet_header_set(struct packet_header *packet_header) +{ + /* Ensure we have values initialized in packet_header_init(). */ + fc_assert(packet_header->length == DIOT_UINT16); + fc_assert(packet_header->type == DIOT_UINT8); + + packet_header->length = DIOT_UINT16; + packet_header->type = DIOT_UINT16; +} + +/**************************************************************************** + Modify if needed the packet header field lengths. +****************************************************************************/ +void post_send_packet_server_join_reply(struct connection *pconn, + const struct packet_server_join_reply + *packet) +{ + if (packet->you_can_join) { + packet_header_set(&pconn->packet_header); + } +} + +/**************************************************************************** + Modify if needed the packet header field lengths. +****************************************************************************/ +void post_receive_packet_server_join_reply(struct connection *pconn, + const struct + packet_server_join_reply *packet) +{ + if (packet->you_can_join) { + packet_header_set(&pconn->packet_header); + } +} + + /************************************************************************** Sanity check packet **************************************************************************/ @@ -557,8 +598,8 @@ bool packet_check(struct data_in *din, struct connection *pc) int type, len; dio_input_rewind(din); - dio_get_uint16(din, &len); - dio_get_uint16(din, &type); + dio_get_type(din, pc->packet_header.length, &len); + dio_get_type(din, pc->packet_header.type, &type); log_packet("received long packet (type %d, len %d, rem %lu) from %s", type, diff --git a/common/packets.def b/common/packets.def index 4b2353a..7ec0e08 100644 --- a/common/packets.def +++ b/common/packets.def @@ -62,8 +62,8 @@ Syntax: PACKET_SERVER_JOIN_REPLY are excluded here. These packets should never change their number. The packet number can be freely chosen as long as it is below 65536 and unique. For backward compatibility - reasons using values from range 1024-1279 ((4x256)-(5*256-1)) - should be avoided. + reasons, packets used for the initial protocol (notably before + checking the capabilities) must be in range 0-255. Packet flags: ------------- @@ -306,10 +306,12 @@ grouped together. There are the following groups: /************** General packets **********************/ # For compatibility with older versions, this number cannot be changed. +# Used in initial protocol. PACKET_PROCESSING_STARTED = 0; sc end # For compatibility with older versions, this number cannot be changed. +# Used in initial protocol. PACKET_PROCESSING_FINISHED = 1; sc end @@ -318,6 +320,7 @@ end # This packet is the first real (freeciv specific) packet send by the # client. The player hasn't been accepted yet. # For compatibility with older versions, this number cannot be changed. +# Used in initial protocol. PACKET_SERVER_JOIN_REQ = 4; cs, dsend, no-delta, no-handle STRING username[MAX_LEN_NAME]; STRING capability[MAX_LEN_CAPSTR]; @@ -327,7 +330,8 @@ end # ... and the server replies. # For compatibility with older versions, this number cannot be changed. -PACKET_SERVER_JOIN_REPLY = 5; sc, no-delta +# Used in initial protocol. +PACKET_SERVER_JOIN_REPLY = 5; sc, no-delta, post-send, post-recv BOOL you_can_join; STRING message[MAX_LEN_MSG]; STRING capability[MAX_LEN_CAPSTR]; @@ -336,11 +340,13 @@ PACKET_SERVER_JOIN_REPLY = 5; sc, no-delta CONNECTION conn_id; end +# Used in initial protocol. PACKET_AUTHENTICATION_REQ = 6; sc, handle-per-conn, dsend AUTH_TYPE type; STRING message[MAX_LEN_MSG]; /* explain to the client if there's a problem */ end +# Used in initial protocol. PACKET_AUTHENTICATION_REPLY = 7; cs, no-handle STRING password[MAX_LEN_PASSWORD]; end @@ -1078,10 +1084,13 @@ PACKET_CONN_PING_INFO = 116; sc, lsend end # For compatibility with older versions, this number cannot be changed. +# Freeciv servers version < 2.5.0 still can send this packet in +# initial protocol. PACKET_CONN_PING = 88; sc end # For compatibility with older versions, this number cannot be changed. +# Can be used in initial protocol, if the client received a PACKET_CONN_PING. PACKET_CONN_PONG = 89; cs, handle-per-conn end diff --git a/common/packets.h b/common/packets.h index bd312dd..68f6b26 100644 --- a/common/packets.h +++ b/common/packets.h @@ -92,51 +92,50 @@ void generic_handle_player_attribute_chunk(struct player *pplayer, const char *packet_name(enum packet_type type); bool packet_has_game_info_flag(enum packet_type type); +inline void packet_header_init(struct packet_header *packet_header); +void post_send_packet_server_join_reply(struct connection *pconn, + const struct packet_server_join_reply + *packet); +void post_receive_packet_server_join_reply(struct connection *pconn, + const struct + packet_server_join_reply *packet); + void pre_send_packet_player_attribute_chunk(struct connection *pc, struct packet_player_attribute_chunk *packet); -#ifdef DEBUG -#define PACKET_TYPE_SANITY(_type_) \ - if (((_type_ & 0xff00) >> 8) == PACKET_SERVER_JOIN_REQ) { \ - log_error("Packet type %s (%d) has upper byte matching old PACKET_SERVER_JOIN_REQ.", \ - packet_name(_type_), _type_); \ - } -#else /* DEBUG */ -#define PACKET_TYPE_SANITY(_type_) -#endif /* DEBUG */ - -#define SEND_PACKET_START(type) \ +#define SEND_PACKET_START(packet_type) \ unsigned char buffer[MAX_LEN_PACKET]; \ struct data_out dout; \ \ dio_output_init(&dout, buffer, sizeof(buffer)); \ - dio_put_uint16(&dout, 0); \ - dio_put_uint16(&dout, type); \ - PACKET_TYPE_SANITY(type) + dio_put_type(&dout, pc->packet_header.length, 0); \ + dio_put_type(&dout, pc->packet_header.type, packet_type); -#define SEND_PACKET_END \ +#define SEND_PACKET_END(packet_type) \ { \ size_t size = dio_output_used(&dout); \ \ dio_output_rewind(&dout); \ - dio_put_uint16(&dout, size); \ + dio_put_type(&dout, pc->packet_header.length, size); \ fc_assert(!dout.too_short); \ - return send_packet_data(pc, buffer, size); \ + return send_packet_data(pc, buffer, size, packet_type); \ } -#define RECEIVE_PACKET_START(type, result) \ +#define RECEIVE_PACKET_START(packet_type, result) \ struct data_in din; \ - struct type packet_buf, *result = &packet_buf; \ + struct packet_type packet_buf, *result = &packet_buf; \ \ - dio_input_init(&din, pc->buffer->data, 2); \ + dio_input_init(&din, pc->buffer->data, \ + data_type_size(pc->packet_header.length)); \ { \ int size; \ \ - dio_get_uint16(&din, &size); \ + dio_get_type(&din, pc->packet_header.length, &size); \ dio_input_init(&din, pc->buffer->data, MIN(size, pc->buffer->ndata)); \ } \ - dio_input_skip(&din, 4); + dio_input_skip(&din, (data_type_size(pc->packet_header.length) \ + + data_type_size(pc->packet_header.type))); #define RECEIVE_PACKET_END(result) \ if (!packet_check(&din, pc)) { \ @@ -151,7 +150,8 @@ void pre_send_packet_player_attribute_chunk(struct connection *pc, log_packet("Error on field '" #field "'" __VA_ARGS__); \ return NULL -int send_packet_data(struct connection *pc, unsigned char *data, int len); +int send_packet_data(struct connection *pc, unsigned char *data, int len, + enum packet_type packet_type); bool packet_check(struct data_in *din, struct connection *pc); /* Utilities to exchange strings and string vectors. */ diff --git a/doc/HACKING b/doc/HACKING index 42ed426..97d2d3a 100644 --- a/doc/HACKING +++ b/doc/HACKING @@ -175,11 +175,19 @@ independent functions such as dio_put_uint32() and de-serialized with functions like dio_get_uint32(). A packet is constituted by header followed by the serialized structure -data. The header contains the following fields: +data. The header contains the following fields (the sizes are defined in +common/packets.c:packet_header_set()): uint16 : length (the length of the entire packet) uint16 : type (e.g. PACKET_TILE_INFO) +For backward compatibility reasons, packets used for the initial protocol +(notably before checking the capabilities) have different header fields +sizes (defined in common/packets.c:packet_header_init()): + +uint16 : length (the length of the entire packet) +uint8 : type (e.g. PACKET_TILE_INFO) + To demonstrate the route for a packet through the system, here's how a unit disband is performed: diff --git a/server/connecthand.c b/server/connecthand.c index 91516aa..8cf20f4 100644 --- a/server/connecthand.c +++ b/server/connecthand.c @@ -329,6 +329,12 @@ bool handle_login_request(struct connection *pconn, char msg[MAX_LEN_MSG]; int kick_time_remaining; + if (pconn->established || pconn->server.status != AS_NOT_ESTABLISHED) { + /* We read the PACKET_SERVER_JOIN_REQ twice from this connection, + * this is probably not a Freeciv client. */ + return FALSE; + } + log_normal(_("Connection request from %s from %s"), req->username, pconn->addr); @@ -404,6 +410,14 @@ bool handle_login_request(struct connection *pconn, } } conn_list_iterate_end; + /* Remove the ping timeout given in sernet.c:server_make_connection(). */ + fc_assert_msg(1 == timer_list_size(pconn->server.ping_timers), + "Ping timer list size %d, should be 1. Have we sent " + "a ping to unestablished connection %s?", + timer_list_size(pconn->server.ping_timers), + conn_description(pconn)); + timer_list_pop_front(pconn->server.ping_timers); + if (game.server.connectmsg[0] != '\0') { log_debug("Sending connectmsg: %s", game.server.connectmsg); dsend_packet_connect_msg(pconn, game.server.connectmsg); diff --git a/server/sernet.c b/server/sernet.c index 81ba517..aa8a29c 100644 --- a/server/sernet.c +++ b/server/sernet.c @@ -590,7 +590,10 @@ enum server_events server_sniff_all_input(void) conn_description(pconn)); connection_close_server(pconn, _("ping timeout")); } - } else { + } else if (pconn->established) { + /* We don't send ping to connection not established, because + * we wouldn't be able to handle asynchronous ping/pong with + * different packet header size. */ connection_ping(pconn); } } conn_list_iterate_end; @@ -984,6 +987,7 @@ static int server_accept_connection(int sockfd) ********************************************************************/ int server_make_connection(int new_sock, const char *client_addr, const char *client_ip) { + struct timer *timer; int i; fc_nonblock(new_sock); @@ -1020,7 +1024,12 @@ int server_make_connection(int new_sock, const char *client_addr, const char *cl log_verbose("connection (%s) from %s (%s)", pconn->username, pconn->addr, pconn->server.ipaddr); - connection_ping(pconn); + /* Give a ping timeout to send the PACKET_SERVER_JOIN_REQ, or close + * the mute connection. This timer will be canceled into + * connecthand.c:handle_login_request(). */ + timer = timer_new(TIMER_USER, TIMER_ACTIVE); + timer_start(timer); + timer_list_append(pconn->server.ping_timers, timer); return 0; } } -- 1.7.9.5