commit 9ba2d0e439e53f8307c808fe26e37b53892a604c Author: George Kadianakis <desnacked@gmail.com> Date: Wed Jul 13 19:00:28 2011 +0200 Create the pluggable_transports.[ch] source files responsible for talking the 180 talk. --- src/or/Makefile.am | 2 + src/or/pluggable_transports.c | 613 +++++++++++++++++++++++++++++++++++++++++ src/or/pluggable_transports.h | 59 ++++ 3 files changed, 674 insertions(+), 0 deletions(-) diff --git a/src/or/Makefile.am b/src/or/Makefile.am index a12d56b..4dc5ee5 100644 --- a/src/or/Makefile.am +++ b/src/or/Makefile.am @@ -39,6 +39,7 @@ libtor_a_SOURCES = \ networkstatus.c \ nodelist.c \ onion.c \ + pluggable_transports.c \ policies.c \ reasons.c \ relay.c \ @@ -104,6 +105,7 @@ noinst_HEADERS = \ ntmain.h \ onion.h \ or.h \ + pluggable_transports.h \ policies.h \ reasons.h \ relay.h \ diff --git a/src/or/pluggable_transports.c b/src/or/pluggable_transports.c new file mode 100644 index 0000000..5448c40 --- /dev/null +++ b/src/or/pluggable_transports.c @@ -0,0 +1,613 @@ +/* Copyright (c) 2011, The Tor Project, Inc. */ +/* See LICENSE for licensing information */ + +/** + * \file pluggable_transports.c + * \brief Pluggable Transports related code. + **/ + +#define PT_PRIVATE +#include "or.h" +#include "config.h" +#include "circuitbuild.h" +#include "pluggable_transports.h" + +/* ASN TIDY THESE UP*/ +static void set_environ(char ***envp, const char *method, + int is_server); +static INLINE int proxy_configuration_finished(managed_proxy_t *mp); + +static void managed_proxy_destroy(managed_proxy_t *mp, + int also_free_transports); +static void register_proxy_transports(managed_proxy_t *mp); +static void handle_finished_proxy(managed_proxy_t *mp); +static void configure_proxy(managed_proxy_t *mp); + +static void parse_method_error(char *line, int is_server_method); +#define parse_server_method_error(l) parse_method_error(l, 1) +#define parse_client_method_error(l) parse_method_error(l, 0) + +static INLINE void free_execve_args(char **arg); + +/** Managed proxy protocol strings */ +#define PROTO_ENV_ERROR "ENV-ERROR" +#define PROTO_NEG_SUCCESS "VERSION" +#define PROTO_NEG_FAIL "VERSION-ERROR no-version" +#define PROTO_CMETHOD "CMETHOD" +#define PROTO_SMETHOD "SMETHOD" +#define PROTO_CMETHOD_ERROR "CMETHOD-ERROR" +#define PROTO_SMETHOD_ERROR "SMETHOD-ERROR" +#define PROTO_CMETHODS_DONE "CMETHODS DONE" +#define PROTO_SMETHODS_DONE "SMETHODS DONE" + +/* The smallest valid managed proxy protocol line that can + appear. It's the size of "VERSION 1" */ +#define SMALLEST_MANAGED_LINE_SIZE 9 + +/** Number of environment variables for managed proxy clients/servers. */ +#define ENVIRON_SIZE_CLIENT 5 +#define ENVIRON_SIZE_SERVER 8 + +/** The first and only supported - at the moment - configuration + protocol version. */ +#define PROTO_VERSION_ONE 1 + +/** List of unconfigured managed proxies. */ +static smartlist_t *unconfigured_proxy_list = NULL; +/** Number of unconfigured managed proxies. */ +static int n_unconfigured_proxies = 0; + +/* The main idea is: + + A managed proxy is represented by a managed_proxy_t struct and can + spawn multiple transports. + + unconfigured_proxy_list is a list of all the unconfigured managed + proxies; everytime we spawn a managed proxy we add it in that + list. + In every run_scheduled_event() tick, we attempt to configure each + managed proxy further, using the configuration protocol defined in + the 180_pluggable_transport.txt proposal. + + When a managed proxy is fully configured, we register all its + transports to the circuitbuild.c subsystem - like we do with + external proxies - and then free the managed proxy struct + since it's no longer needed. */ + +/** Return true if there are still unconfigured managed proxies. */ +int +pt_proxies_configuration_pending(void) +{ + return !!n_unconfigured_proxies; +} + +/** Launch a proxy for <b>method</b> using <b>proxy_argv</b> as its + * arguments. If <b>is_server</b>, launch a server proxy. */ +int +pt_managed_launch_proxy(const char *method, + char **proxy_argv, int is_server) +{ + char **envp=NULL; + int retval; + FILE *stdout_read = NULL; + int stdout_pipe=-1, stderr_pipe=-1; + + /* prepare the environment variables for the managed proxy */ + set_environ(&envp, method, is_server); + + /* ASN we should probably check if proxy_argv[0] is executable by our user */ + retval = tor_spawn_background(proxy_argv[0], &stdout_pipe, + &stderr_pipe, (const char **)proxy_argv, + (const char **)envp); + if (retval < 0) { + log_warn(LD_GENERAL, "Spawn failed"); + return -1; + } + + /* free the memory allocated for the execve() */ + free_execve_args(envp); + free_execve_args(proxy_argv); + + /* Set stdout/stderr pipes to be non-blocking */ + fcntl(stdout_pipe, F_SETFL, O_NONBLOCK); + /* Open the buffered IO streams */ + stdout_read = fdopen(stdout_pipe, "r"); + + log_warn(LD_CONFIG, "The spawn is alive (%d)!", retval); + + /* create a managed proxy */ + managed_proxy_t *mp = tor_malloc(sizeof(managed_proxy_t)); + mp->conf_state = PT_PROTO_INFANT; + mp->stdout = stdout_read; + mp->transports = smartlist_create(); + + /* register the managed proxy */ + if (!unconfigured_proxy_list) + unconfigured_proxy_list = smartlist_create(); + smartlist_add(unconfigured_proxy_list, mp); + + n_unconfigured_proxies++; /* ASN should we care about overflows here? + I say no. */ + + return 0; +} + +/** Check if any of the managed proxies we are currently trying to + * configure have anything new to say. This is called from + * run_scheduled_events(). */ +void +pt_configure_remaining_proxies(void) +{ + log_warn(LD_CONFIG, "We start configuring remaining managed proxies!"); + SMARTLIST_FOREACH_BEGIN(unconfigured_proxy_list, managed_proxy_t *, mp) { + if (proxy_configuration_finished(mp)) /* finished managed proxies + shouldn't be here */ + assert(0); + + configure_proxy(mp); + + } SMARTLIST_FOREACH_END(mp); +} + +/** Receive input from the managed proxy <b>mp</b> to get closer to + * finally configuring it. */ +static void +configure_proxy(managed_proxy_t *mp) +{ + enum stream_status r; + char stdout_buf[200]; + + while (1) { + memset(stdout_buf, 0, sizeof(stdout_buf)); + + r = get_string_from_pipe(mp->stdout, stdout_buf, + sizeof(stdout_buf) - 1); + + if (r == ST_CLOSED || r == ST_TERM) { + log_warn(LD_GENERAL, "Managed proxy stream closed. " + "Most probably application stopped running"); + mp->conf_state = PT_PROTO_BROKEN; + } else if (r == ST_EAGAIN) { + return; + } else { + tor_assert(r == ST_OKAY); + handle_proxy_line(stdout_buf, mp); + } + + /* if the proxy finished configuring, exit the loop. */ + if (proxy_configuration_finished(mp)) { + handle_finished_proxy(mp); + return; + } + } +} + +/** Handle a configured or broken managed proxy <b>mp</b>. */ +static void +handle_finished_proxy(managed_proxy_t *mp) +{ + switch (mp->conf_state) { + case PT_PROTO_BROKEN: /* if broken: */ + managed_proxy_destroy(mp, 1); /* destroy it and all its transports */ + break; + case PT_PROTO_CONFIGURED: /* if configured correctly: */ + register_proxy_transports(mp); /* register all its transports, */ + mp->conf_state = PT_PROTO_COMPLETED; /* mark it as completed, */ + managed_proxy_destroy(mp, 0); /* destroy the managed proxy struct, + keeping the transports intact */ + break; + default: + log_warn(LD_CONFIG, "Unfinished managed proxy in " + "handle_finished_proxy()."); + assert(0); + } + + n_unconfigured_proxies--; + tor_assert(n_unconfigured_proxies >= 0); +} + +/** Register all the transports supported by managed proxy <b>mp</b>. */ +static void +register_proxy_transports(managed_proxy_t *mp) +{ + SMARTLIST_FOREACH_BEGIN(mp->transports, transport_t *, t) { + if (transport_add(t)<0) { + log_warn(LD_GENERAL, "Could not add transport %s. Skipping.", t->name); + transport_free(t); + } else { + log_warn(LD_GENERAL, "Succesfully registered transport %s", t->name); + } + } SMARTLIST_FOREACH_END(t); +} + +/** Free memory allocated by managed proxy <b>mp</b>. + * If <b>also_free_transports</b> is set, also free the transports + * associated with this managed proxy. */ +static void +managed_proxy_destroy(managed_proxy_t *mp, int also_free_transports) +{ + /* transport_free() all its transports */ + if (also_free_transports) + SMARTLIST_FOREACH(mp->transports, transport_t *, t, transport_free(t)); + + /* free the transports smartlist */ + smartlist_clear(mp->transports); + smartlist_free(mp->transports); + + /* remove it from the list of managed proxies */ + smartlist_remove(unconfigured_proxy_list, mp); + + /* close its stdout stream */ + fclose(mp->stdout); + + tor_free(mp); +} + +/** Return true if the configuration of the managed proxy <b>mp</b> is + finished. */ +static INLINE int +proxy_configuration_finished(managed_proxy_t *mp) +{ + return (mp->conf_state == PT_PROTO_CONFIGURED || + mp->conf_state == PT_PROTO_BROKEN); +} + +/** Handle a configuration protocol <b>line</b> received from a + * managed proxy <b>mp</b>. */ +void +handle_proxy_line(char *line, managed_proxy_t *mp) +{ + printf("Judging line: %s\n", line); + + if (strlen(line) < SMALLEST_MANAGED_LINE_SIZE) { + log_warn(LD_GENERAL, "Managed proxy configuration line is too small. " + "Discarding"); + goto err; + } + + if (!strncmp(line, PROTO_ENV_ERROR, strlen(PROTO_ENV_ERROR))) { + if (mp->conf_state != PT_PROTO_INFANT) + goto err; + + parse_env_error(line); + goto err; + } else if (!strncmp(line, PROTO_NEG_FAIL, strlen(PROTO_NEG_FAIL))) { + if (mp->conf_state != PT_PROTO_INFANT) + goto err; + + log_warn(LD_CONFIG, "Managed proxy could not pick a " + "configuration protocol version."); + goto err; + } else if (!strncmp(line, PROTO_NEG_SUCCESS, + strlen(PROTO_NEG_SUCCESS))) { + if (mp->conf_state != PT_PROTO_INFANT) + goto err; + + if (parse_version(line,mp) < 0) + goto err; + + tor_assert(mp->conf_protocol != 0); + mp->conf_state = PT_PROTO_ACCEPTING_METHODS; + return; + } else if (!strncmp(line, PROTO_CMETHODS_DONE, + strlen(PROTO_CMETHODS_DONE))) { + if (mp->conf_state != PT_PROTO_ACCEPTING_METHODS) + goto err; + + log_warn(LD_CONFIG, "Client managed proxy configuration completed!"); + mp->conf_state = PT_PROTO_CONFIGURED; + return; + } else if (!strncmp(line, PROTO_SMETHODS_DONE, + strlen(PROTO_SMETHODS_DONE))) { + if (mp->conf_state != PT_PROTO_ACCEPTING_METHODS) + goto err; + + log_warn(LD_CONFIG, "Server managed proxy configuration completed!"); + mp->conf_state = PT_PROTO_CONFIGURED; + return; + } else if (!strncmp(line, PROTO_CMETHOD_ERROR, + strlen(PROTO_CMETHOD_ERROR))) { + if (mp->conf_state != PT_PROTO_ACCEPTING_METHODS) + goto err; + + parse_client_method_error(line); + goto err; + } else if (!strncmp(line, PROTO_SMETHOD_ERROR, + strlen(PROTO_SMETHOD_ERROR))) { + if (mp->conf_state != PT_PROTO_ACCEPTING_METHODS) + goto err; + + parse_server_method_error(line); + goto err; + } else if (!strncmp(line, PROTO_CMETHOD, strlen(PROTO_CMETHOD))) { + if (mp->conf_state != PT_PROTO_ACCEPTING_METHODS) + goto err; + + if (parse_cmethod_line(line, mp) < 0) + goto err; + + return; + } else if (!strncmp(line, PROTO_SMETHOD, strlen(PROTO_SMETHOD))) { + if (mp->conf_state != PT_PROTO_ACCEPTING_METHODS) + goto err; + + if (parse_smethod_line(line, mp) < 0) + goto err; + + return; + } + + log_warn(LD_CONFIG, "Unknown line received by managed proxy. (%s)", line); + + err: + mp->conf_state = PT_PROTO_BROKEN; + return; +} + +/** Parses an ENV-ERROR <b>line</b> and warns the user accordingly. */ +void +parse_env_error(char *line) +{ + tor_assert(!strncmp(line, PROTO_ENV_ERROR, strlen(PROTO_ENV_ERROR))); + + /* (Length of the protocol string) plus (a space) and (the first char of + the error message) */ + if (strlen(line) < (strlen(PROTO_ENV_ERROR) + 2)) + log_warn(LD_CONFIG, "Managed proxy sent us an %s without an error " + "message.", PROTO_ENV_ERROR); + + log_warn(LD_CONFIG, "Managed proxy couldn't understand the " + "pluggable transport environment variables. (%s)", + line+strlen(PROTO_ENV_ERROR)+1); +} + +/** Handles a VERSION <b>line</b>. Updates the configuration protocol + * version in <b>mp</b>. */ +int +parse_version(char *line, managed_proxy_t *mp) +{ + tor_assert(!strncmp(line, PROTO_NEG_SUCCESS, strlen(PROTO_NEG_SUCCESS))); + + if (strlen(line) < (strlen(PROTO_NEG_SUCCESS) + 2)) { + log_warn(LD_CONFIG, "Managed proxy sent us malformed %s line.", + PROTO_NEG_SUCCESS); + return -1; + } + + if (strcmp("1", line+strlen(PROTO_NEG_SUCCESS)+1)) { + log_warn(LD_CONFIG, "We don't support version '%s'. " + "We only support version '1'", line+strlen(PROTO_NEG_SUCCESS)+1); + return -1; + } + + mp->conf_protocol = PROTO_VERSION_ONE; /* temp. till more versions appear */ + return 0; +} + +/** Parses {C,S}METHOD-ERROR <b>line</b> and warns the user + * accordingly. If <b>is_server</b> it is an SMETHOD-ERROR, + * otherwise it is a CMETHOD-ERROR. */ +static void +parse_method_error(char *line, int is_server) +{ + const char* error = is_server ? + PROTO_SMETHOD_ERROR : PROTO_CMETHOD_ERROR; + + /* (Length of the protocol string) plus (a space) and (the first char of + the error message) */ + if (strlen(line) < (strlen(error) + 2)) + log_warn(LD_CONFIG, "Managed proxy sent us an %s without an error " + "message.", error); + + log_warn(LD_CONFIG, "%s managed proxy encountered a method error. (%s)", + is_server ? "Server" : "Client", + line+strlen(error)+1); +} + +/** Parses an SMETHOD <b>line</b>. */ +int +parse_smethod_line(char *line, managed_proxy_t *mp) +{ + int r; + smartlist_t *items = NULL; + + char *method_name=NULL; + + char *addrport=NULL; + tor_addr_t addr; + uint16_t port = 0; + + items = smartlist_create(); + smartlist_split_string(items, line, NULL, + SPLIT_SKIP_SPACE|SPLIT_IGNORE_BLANK, -1); + if (smartlist_len(items) < 3) { + log_warn(LD_CONFIG, "Server managed proxy sent us a SMETHOD line " + "with too few arguments."); + goto err; + } + + tor_assert(!strcmp(smartlist_get(items,0),PROTO_SMETHOD)); + + method_name = smartlist_get(items,1); + + addrport = smartlist_get(items, 2); + if (tor_addr_port_parse(addrport, &addr, &port)<0) { + log_warn(LD_CONFIG, "Error parsing transport " + "address '%s'", addrport); + goto err; + } + + if (!port) { + log_warn(LD_CONFIG, + "Transport address '%s' has no port.", addrport); + goto err; + } + + /* For now, notify the user so that he knows where the server + transport is listening. */ + log_warn(LD_CONFIG, "Server transport %s at %s:%d.", + method_name, fmt_addr(&addr), (int)port); + + r=0; + goto done; + + err: + r = -1; + + done: + SMARTLIST_FOREACH(items, char*, s, tor_free(s)); + smartlist_free(items); + return r; +} + +/** Parses a CMETHOD <b>line</b>, and if well-formed it registers + * the new transport in <b>mp</b>. */ +int +parse_cmethod_line(char *line, managed_proxy_t *mp) +{ + int r; + smartlist_t *items = NULL; + + char *method_name=NULL; + + char *socks_ver_str=NULL; + int socks_ver=PROXY_NONE; + + char *addrport=NULL; + tor_addr_t addr; + uint16_t port = 0; + + transport_t *transport=NULL; + + items = smartlist_create(); + smartlist_split_string(items, line, NULL, + SPLIT_SKIP_SPACE|SPLIT_IGNORE_BLANK, -1); + if (smartlist_len(items) < 4) { + log_warn(LD_CONFIG, "Client managed proxy sent us a CMETHOD line " + "with too few arguments."); + goto err; + } + + tor_assert(!strcmp(smartlist_get(items,0),PROTO_CMETHOD)); + + method_name = smartlist_get(items,1); + + socks_ver_str = smartlist_get(items,2); + + if (!strcmp(socks_ver_str,"socks4")) { + socks_ver = PROXY_SOCKS4; + } else if (!strcmp(socks_ver_str,"socks5")) { + socks_ver = PROXY_SOCKS5; + } else { + log_warn(LD_CONFIG, "Client managed proxy sent us a proxy protocol " + "we don't recognize. (%s)", socks_ver_str); + goto err; + } + + addrport = smartlist_get(items, 3); + if (tor_addr_port_parse(addrport, &addr, &port)<0) { + log_warn(LD_CONFIG, "Error parsing transport " + "address '%s'", addrport); + goto err; + } + + if (!port) { + log_warn(LD_CONFIG, + "Transport address '%s' has no port.", addrport); + goto err; + } + + transport = transport_create(&addr, port, method_name, socks_ver); + if (!transport) + goto err; + + smartlist_add(mp->transports, transport); + + log_warn(LD_CONFIG, "Transport %s at %s:%d with SOCKS %d. " + "Attached to managed proxy.", + method_name, fmt_addr(&addr), (int)port, socks_ver); + + r=0; + goto done; + + err: + r = -1; + + done: + SMARTLIST_FOREACH(items, char*, s, tor_free(s)); + smartlist_free(items); + return r; +} + +/** Prepares the <b>envp</b> of a pluggable transport managed proxy + * + * <b>method</b> is a line with transport methods to be launched. + * If <b>is_server</b> is set, prepare a server proxy <b>envp</b>. */ +static void +set_environ(char ***envp, const char *method, int is_server) +{ + or_options_t *options = get_options(); + char **tmp=NULL; + char *state_loc=NULL; + + int n_envs = is_server ? ENVIRON_SIZE_SERVER : ENVIRON_SIZE_CLIENT; + + /* allocate enough space for our env. vars and a NULL pointer */ + *envp = tor_malloc(sizeof(char*)*(n_envs+1)); + tmp = *envp; + + /* these should all be customizable */ + tor_asprintf(tmp++, "HOME=%s", getenv("HOME")); + tor_asprintf(tmp++, "PATH=%s", getenv("PATH")); + state_loc = get_datadir_fname("pt_state/"); + tor_asprintf(tmp++, "TOR_PT_STATE_LOCATION=%s", state_loc); + tor_free(state_loc); + tor_asprintf(tmp++, "TOR_PT_MANAGED_TRANSPORT_VER=1"); /* temp */ + if (is_server) { + /* ASN check for ORPort values, should we be here if it's 0? */ + tor_asprintf(tmp++, "TOR_PT_ORPORT=%d", options->ORPort); + tor_asprintf(tmp++, "TOR_PT_SERVER_BINDADDR=127.0.0.1:0"); + tor_asprintf(tmp++, "TOR_PT_SERVER_TRANSPORTS=%s", method); + tor_asprintf(tmp++, "TOR_PT_EXTENDED_SERVER_PORT=4200"); + } else { + tor_asprintf(tmp++, "TOR_PT_CLIENT_TRANSPORTS=%s", method); + } + *tmp = NULL; +} + +/* ASN is this too ugly/stupid? */ +/** Frees the array of pointers in <b>arg</b> used as arguments to + execve. */ +static INLINE void +free_execve_args(char **arg) +{ + char **tmp = arg; + while (*tmp) /* use the fact that the last element of the array is a + NULL pointer to know when to stop freeing */ + _tor_free(*tmp++); + + tor_free(arg); +} + +/** Release all storage held by the pluggable transports subsystem. */ +void +pt_free_all(void) +{ + if (unconfigured_proxy_list) { + /* If the proxy is in PT_PROTO_COMPLETED, it has registered its + transports and it's the duty of the circuitbuild.c subsystem to + free them. Otherwise, it hasn't registered its transports yet + and we should free them here. */ + SMARTLIST_FOREACH_BEGIN(unconfigured_proxy_list, managed_proxy_t *, mp) { + if (mp->conf_state == PT_PROTO_COMPLETED) + managed_proxy_destroy(mp,0); + else + managed_proxy_destroy(mp,1); + } SMARTLIST_FOREACH_END(mp); + + smartlist_clear(unconfigured_proxy_list); + smartlist_free(unconfigured_proxy_list); + unconfigured_proxy_list=NULL; + } +} + diff --git a/src/or/pluggable_transports.h b/src/or/pluggable_transports.h new file mode 100644 index 0000000..80d5429 --- /dev/null +++ b/src/or/pluggable_transports.h @@ -0,0 +1,59 @@ +/* Copyright (c) 2003-2004, Roger Dingledine + * Copyright (c) 2004-2006, Roger Dingledine, Nick Mathewson. + * Copyright (c) 2007-2011, The Tor Project, Inc. */ +/* See LICENSE for licensing information */ + +/** + * \file pluggable_transpots.h + * \brief Headers for pluggable_transpots.c + **/ + +#ifndef TOR_PLUGGABLE_TRANSPORTS_H +#define TOR_PLUGGABLE_TRANSPORTS_H + +int pt_managed_launch_proxy(const char *method, + char **proxy_argv, int is_server); + +#define pt_managed_launch_client_proxy(m, pa) \ + pt_managed_launch_proxy(m, pa, 0) +#define pt_managed_launch_server_proxy(m, pa) \ + pt_managed_launch_proxy(m, pa, 1) + +void pt_configure_remaining_proxies(void); + +int pt_proxies_configuration_pending(void); + +void pt_free_all(void); + +#ifdef PT_PRIVATE +/** State of the managed proxy configuration protocol. */ +enum pt_proto_state { + PT_PROTO_INFANT, /* was just born */ + PT_PROTO_ACCEPTING_METHODS, /* accepting methods */ + PT_PROTO_CONFIGURED, /* configured successfully */ + PT_PROTO_COMPLETED, /* configure and registered its transports */ + PT_PROTO_BROKEN +}; + +/** Structure containing information of a managed proxy. */ +typedef struct { + enum pt_proto_state conf_state; /* the current configuration state */ + int conf_protocol; /* the configuration protocol version used */ + + FILE *stdout; /* a stream to its stdout + (closed in managed_proxy_destroy()) */ + + smartlist_t *transports; /* list of transports this proxy spawns */ +} managed_proxy_t; + +int parse_cmethod_line(char *line, managed_proxy_t *mp); +int parse_smethod_line(char *line, managed_proxy_t *mp); + +int parse_version(char *line, managed_proxy_t *mp); +void parse_env_error(char *line); +void handle_proxy_line(char *line, managed_proxy_t *mp); + +#endif + +#endif +