PPTP源码(Linux and FreeBSD)

/* pptp_ctrl.c ... handle PPTP control connection. * C. Scott Ananian <cananian@alumni.princeton.edu> * * $Id: pptp_ctrl.c,v 1.33 2007/11/21 03:36:47 quozl Exp $ */ #include <errno.h> #include <sys/time.h> #include <sys/types.h> #include <sys/socket.h> #include <netinet/in.h> #include <unistd.h> #include <stdlib.h> #include <assert.h> #include <signal.h> #include <string.h> #include <ctype.h> #include <fcntl.h> #include "pptp_msg.h" #include "pptp_ctrl.h" #include "pptp_options.h" #include "vector.h" #include "util.h" #include "pptp_quirks.h" /* BECAUSE OF SIGNAL LIMITATIONS, EACH PROCESS CAN ONLY MANAGE ONE * CONNECTION. SO THIS 'PPTP_CONN' STRUCTURE IS A BIT MISLEADING. * WE'LL KEEP CONNECTION-SPECIFIC INFORMATION IN THERE ANYWAY (AS * OPPOSED TO USING GLOBAL VARIABLES), BUT BEWARE THAT THE ENTIRE * UNIX SIGNAL-HANDLING SEMANTICS WOULD HAVE TO CHANGE (OR THE * TIME-OUT CODE DRASTICALLY REWRITTEN) BEFORE YOU COULD DO A * PPTP_CONN_OPEN MORE THAN ONCE PER PROCESS AND GET AWAY WITH IT. */ /* This structure contains connection-specific information that the * signal handler needs to see. Thus, it needs to be in a global * variable. If you end up using pthreads or something (why not * just processes?), this would have to be placed in a thread-specific * data area, using pthread_get|set_specific, etc., so I've * conveniently encapsulated it for you. * [linux threads will have to support thread-specific signals * before this would work at all, which, as of this writing * (linux-threads v0.6, linux kernel 2.1.72), it does not.] */ /* Globals */ /* control the number of times echo packets will be logged */ static int nlogecho = 10; static struct thread_specific { struct sigaction old_sigaction; /* evil signals */ PPTP_CONN * conn; } global; #define INITIAL_BUFSIZE 512 /* initial i/o buffer size. */ struct PPTP_CONN { int inet_sock; /* Connection States */ enum { CONN_IDLE, CONN_WAIT_CTL_REPLY, CONN_WAIT_STOP_REPLY, CONN_ESTABLISHED } conn_state; /* on startup: CONN_IDLE */ /* Keep-alive states */ enum { KA_NONE, KA_OUTSTANDING } ka_state; /* on startup: KA_NONE */ /* Keep-alive ID; monotonically increasing (watch wrap-around!) */ u_int32_t ka_id; /* on startup: 1 */ /* Other properties. */ u_int16_t version; u_int16_t firmware_rev; u_int8_t hostname[64], vendor[64]; /* XXX these are only PNS properties, currently XXX */ /* Call assignment information. */ u_int16_t call_serial_number; VECTOR *call; void * closure; pptp_conn_cb callback; /******* IO buffers ******/ char * read_buffer, *write_buffer; size_t read_alloc, write_alloc; size_t read_size, write_size; }; struct PPTP_CALL { /* Call properties */ enum { PPTP_CALL_PAC, PPTP_CALL_PNS } call_type; union { enum pptp_pac_state { PAC_IDLE, PAC_WAIT_REPLY, PAC_ESTABLISHED, PAC_WAIT_CS_ANS } pac; enum pptp_pns_state { PNS_IDLE, PNS_WAIT_REPLY, PNS_ESTABLISHED, PNS_WAIT_DISCONNECT } pns; } state; u_int16_t call_id, peer_call_id; u_int16_t sernum; u_int32_t speed; /* For user data: */ pptp_call_cb callback; void * closure; }; /* PPTP error codes: ----------------------------------------------*/ /* (General Error Codes) */ static const struct { const char *name, *desc; } pptp_general_errors[] = { #define PPTP_GENERAL_ERROR_NONE 0 { "(None)", "No general error" }, #define PPTP_GENERAL_ERROR_NOT_CONNECTED 1 { "(Not-Connected)", "No control connection exists yet for this " "PAC-PNS pair" }, #define PPTP_GENERAL_ERROR_BAD_FORMAT 2 { "(Bad-Format)", "Length is wrong or Magic Cookie value is incorrect" }, #define PPTP_GENERAL_ERROR_BAD_VALUE 3 { "(Bad-Value)", "One of the field values was out of range or " "reserved field was non-zero" }, #define PPTP_GENERAL_ERROR_NO_RESOURCE 4 { "(No-Resource)", "Insufficient resources to handle this command now" }, #define PPTP_GENERAL_ERROR_BAD_CALLID 5 { "(Bad-Call ID)", "The Call ID is invalid in this context" }, #define PPTP_GENERAL_ERROR_PAC_ERROR 6 { "(PAC-Error)", "A generic vendor-specific error occured in the PAC" } }; #define MAX_GENERAL_ERROR ( sizeof(pptp_general_errors) / \ sizeof(pptp_general_errors[0]) - 1) /* Outgoing Call Reply Result Codes */ static const char *pptp_out_call_reply_result[] = { /* 0 */ "Unknown Result Code", /* 1 */ "Connected", /* 2 */ "General Error", /* 3 */ "No Carrier Detected", /* 4 */ "Busy Signal", /* 5 */ "No Dial Tone", /* 6 */ "Time Out", /* 7 */ "Not Accepted, Call is administratively prohibited" }; #define MAX_OUT_CALL_REPLY_RESULT 7 /* Call Disconnect Notify Result Codes */ static const char *pptp_call_disc_ntfy[] = { /* 0 */ "Unknown Result Code", /* 1 */ "Lost Carrier", /* 2 */ "General Error", /* 3 */ "Administrative Shutdown", /* 4 */ "(your) Request" }; #define MAX_CALL_DISC_NTFY 4 /* Call Disconnect Notify Result Codes */ static const char *pptp_start_ctrl_conn_rply[] = { /* 0 */ "Unknown Result Code", /* 1 */ "Successful Channel Establishment", /* 2 */ "General Error", /* 3 */ "Command Channel Already Exists", /* 4 */ "Requester is not Authorized" }; #define MAX_START_CTRL_CONN_REPLY 4 /* timing options */ int idle_wait = PPTP_TIMEOUT; int max_echo_wait = PPTP_TIMEOUT; /* Local prototypes */ static void pptp_reset_timer(void); static void pptp_handle_timer(); /* Write/read as much as we can without blocking. */ int pptp_write_some(PPTP_CONN * conn); int pptp_read_some(PPTP_CONN * conn); /* Make valid packets from read_buffer */ int pptp_make_packet(PPTP_CONN * conn, void **buf, size_t *size); /* Add packet to write_buffer */ int pptp_send_ctrl_packet(PPTP_CONN * conn, void * buffer, size_t size); /* Dispatch packets (general) */ int pptp_dispatch_packet(PPTP_CONN * conn, void * buffer, size_t size); /* Dispatch packets (control messages) */ int ctrlp_disp(PPTP_CONN * conn, void * buffer, size_t size); /* Set link info, for pptp servers that need it. this is a noop, unless the user specified a quirk and there's a set_link hook defined in the quirks table for that quirk */ void pptp_set_link(PPTP_CONN * conn, int peer_call_id); /*** log error information in control packets *********************************/ static void ctrlp_error( int result, int error, int cause, const char *result_text[], int max_result) { if( cause >= 0) log("Result code is %d '%s'. Error code is %d, Cause code is %d", result, result_text[result <= max_result ? result : 0], error, cause ); else log("Reply result code is %d '%s'. Error code is %d", result, result_text[result <= max_result ? result : 0], error); if ((error > 0) && (error <= MAX_GENERAL_ERROR)){ if( result != PPTP_RESULT_GENERAL_ERROR ) log("Result code is something else then \"general error\", " "so the following error is probably bogus."); log("Error is '%s', Error message: '%s'", pptp_general_errors[error].name, pptp_general_errors[error].desc); } } static const char *ctrl_msg_types[] = { "invalid control message type", /* (Control Connection Management) */ "Start-Control-Connection-Request", /* 1 */ "Start-Control-Connection-Reply", /* 2 */ "Stop-Control-Connection-Request", /* 3 */ "Stop-Control-Connection-Reply", /* 4 */ "Echo-Request", /* 5 */ "Echo-Reply", /* 6 */ /* (Call Management) */ "Outgoing-Call-Request", /* 7 */ "Outgoing-Call-Reply",