diff options
Diffstat (limited to 'src/or/transports.c')
| -rw-r--r-- | src/or/transports.c | 1221 |
1 files changed, 1221 insertions, 0 deletions
diff --git a/src/or/transports.c b/src/or/transports.c new file mode 100644 index 000000000..4ba239562 --- /dev/null +++ b/src/or/transports.c @@ -0,0 +1,1221 @@ +/* Copyright (c) 2011-2012, The Tor Project, Inc. */ +/* See LICENSE for licensing information */ + +/** + * \file transports.c + * \brief Pluggable Transports related code. + * + * \details + * Each managed proxy is represented by a <b>managed_proxy_t</b>. + * Each managed proxy can support multiple transports. + * Each managed proxy gets configured through a multistep process. + * + * ::managed_proxy_list contains all the managed proxies this tor + * instance is supporting. + * In the ::managed_proxy_list there are ::unconfigured_proxies_n + * managed proxies that are still unconfigured. + * + * In every run_scheduled_event() tick, we attempt to launch and then + * configure the unconfiged managed proxies, using the configuration + * protocol defined in the 180_pluggable_transport.txt proposal. A + * managed proxy might need several ticks to get fully configured. + * + * When a managed proxy is fully configured, we register all its + * transports to the circuitbuild.c subsystem. At that point the + * transports are owned by the circuitbuild.c subsystem. + * + * When a managed proxy fails to follow the 180 configuration + * protocol, it gets marked as broken and gets destroyed. + * + * <b>In a little more detail:</b> + * + * While we are serially parsing torrc, we store all the transports + * that a proxy should spawn in its <em>transports_to_launch</em> + * element. + * + * When we finish reading the torrc, we spawn the managed proxy and + * expect {S,C}METHOD lines from its output. We add transports + * described by METHOD lines to its <em>transports</em> element, as + * transport_t structs. + * + * When the managed proxy stops spitting METHOD lines (signified by a + * '{S,C}METHODS DONE' message) we register all the transports + * collected to the circuitbuild.c subsystem. At this point, the + * pointers to transport_t can be transformed into dangling pointers + * at any point by the circuitbuild.c subsystem, and so we replace all + * transport_t pointers with strings describing the transport names. + * We can still go from a transport name to a transport_t using the + * fact that each transport name uniquely identifies a transport_t. + * + * <b>In even more detail, this is what happens when a SIGHUP + * occurs:</b> + * + * We immediately destroy all unconfigured proxies (We shouldn't have + * unconfigured proxies in the first place, except when SIGHUP rings + * immediately after tor is launched.). + * + * We mark all managed proxies and transports to signify that they + * must be removed if they don't contribute by the new torrc + * (we mark using the <b>marked_for_removal</b> element). + * We also mark all managed proxies to signify that they might need to + * be restarted so that they end up supporting all the transports the + * new torrc wants them to support (using the <b>got_hup</b> element). + * We also clear their <b>transports_to_launch</b> list so that we can + * put there the transports we need to launch according to the new + * torrc. + * + * We then start parsing torrc again. + * + * Everytime we encounter a transport line using a known pre-SIGHUP + * managed proxy, we cleanse that proxy from the removal mark. + * We also mark it as unconfigured so that on the next scheduled + * events tick, we investigate whether we need to restart the proxy + * so that it also spawns the new transports. + * If the post-SIGHUP <b>transports_to_launch</b> list is identical to + * the pre-SIGHUP one, it means that no changes were introduced to + * this proxy during the SIGHUP and no restart has to take place. + * + * During the post-SIGHUP torrc parsing, we unmark all transports + * spawned by managed proxies that we find in our torrc. + * We do that so that if we don't need to restart a managed proxy, we + * can continue using its old transports normally. + * If we end up restarting the proxy, we destroy and unregister all + * old transports from the circuitbuild.c subsystem. + **/ + +#define PT_PRIVATE +#include "or.h" +#include "config.h" +#include "circuitbuild.h" +#include "transports.h" +#include "util.h" +#include "router.h" + +static process_environment_t * +create_managed_proxy_environment(const managed_proxy_t *mp); + +static INLINE int proxy_configuration_finished(const managed_proxy_t *mp); + +static void managed_proxy_destroy(managed_proxy_t *mp, + int also_terminate_process); + +static void handle_finished_proxy(managed_proxy_t *mp); +static void configure_proxy(managed_proxy_t *mp); + +static void parse_method_error(const 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" + +/** Number of environment variables for managed proxy clients/servers. */ +#define ENVIRON_SIZE_CLIENT 3 +#define ENVIRON_SIZE_SERVER 7 /* XXX known to be too high, but that's ok */ + +/** The first and only supported - at the moment - configuration + protocol version. */ +#define PROTO_VERSION_ONE 1 + +/** List of unconfigured managed proxies. */ +static smartlist_t *managed_proxy_list = NULL; +/** Number of still unconfigured proxies. */ +static int unconfigured_proxies_n = 0; +/** Boolean: True iff we might need to restart some proxies. */ +static int check_if_restarts_needed = 0; + +/** Return true if there are still unconfigured managed proxies, or proxies + * that need restarting. */ +int +pt_proxies_configuration_pending(void) +{ + return unconfigured_proxies_n || check_if_restarts_needed; +} + +/** Assert that the unconfigured_proxies_n value correctly matches the number + * of proxies in a state other than PT_PROTO_COMPLETE. */ +static void +assert_unconfigured_count_ok(void) +{ + int n_completed = 0; + if (!managed_proxy_list) { + tor_assert(unconfigured_proxies_n == 0); + return; + } + + SMARTLIST_FOREACH(managed_proxy_list, managed_proxy_t *, mp, { + if (mp->conf_state == PT_PROTO_COMPLETED) + ++n_completed; + }); + + tor_assert(n_completed + unconfigured_proxies_n == + smartlist_len(managed_proxy_list)); +} + +/** Return true if <b>mp</b> has the same argv as <b>proxy_argv</b> */ +static int +managed_proxy_has_argv(const managed_proxy_t *mp, char **proxy_argv) +{ + char **tmp1=proxy_argv; + char **tmp2=mp->argv; + + tor_assert(tmp1); + tor_assert(tmp2); + + while (*tmp1 && *tmp2) { + if (strcmp(*tmp1++, *tmp2++)) + return 0; + } + + if (!*tmp1 && !*tmp2) + return 1; + + return 0; +} + +/** Return a managed proxy with the same argv as <b>proxy_argv</b>. + * If no such managed proxy exists, return NULL. */ +static managed_proxy_t * +get_managed_proxy_by_argv_and_type(char **proxy_argv, int is_server) +{ + if (!managed_proxy_list) + return NULL; + + SMARTLIST_FOREACH_BEGIN(managed_proxy_list, managed_proxy_t *, mp) { + if (managed_proxy_has_argv(mp, proxy_argv) && + mp->is_server == is_server) + return mp; + } SMARTLIST_FOREACH_END(mp); + + return NULL; +} + +/** Add <b>transport</b> to managed proxy <b>mp</b>. */ +static void +add_transport_to_proxy(const char *transport, managed_proxy_t *mp) +{ + tor_assert(mp->transports_to_launch); + if (!smartlist_string_isin(mp->transports_to_launch, transport)) + smartlist_add(mp->transports_to_launch, tor_strdup(transport)); +} + +/** Called when a SIGHUP occurs. Returns true if managed proxy + * <b>mp</b> needs to be restarted after the SIGHUP, based on the new + * torrc. */ +static int +proxy_needs_restart(const managed_proxy_t *mp) +{ + /* mp->transport_to_launch is populated with the names of the + transports that must be launched *after* the SIGHUP. + mp->transports is populated with the names of the transports that + were launched *before* the SIGHUP. + + If the two lists contain the same strings, we don't need to + restart the proxy, since it already does what we want. */ + + tor_assert(smartlist_len(mp->transports_to_launch) > 0); + tor_assert(mp->conf_state == PT_PROTO_COMPLETED); + + if (smartlist_len(mp->transports_to_launch) != smartlist_len(mp->transports)) + goto needs_restart; + + SMARTLIST_FOREACH_BEGIN(mp->transports_to_launch, char *, t_t_l) { + if (!smartlist_string_isin(mp->transports, t_t_l)) + goto needs_restart; + + } SMARTLIST_FOREACH_END(t_t_l); + + return 0; + + needs_restart: + return 1; +} + +/** Managed proxy <b>mp</b> must be restarted. Do all the necessary + * preparations and then flag its state so that it will be relaunched + * in the next tick. */ +static void +proxy_prepare_for_restart(managed_proxy_t *mp) +{ + transport_t *t_tmp = NULL; + + tor_assert(mp->conf_state == PT_PROTO_COMPLETED); + + /* destroy the process handle and terminate the process. */ + tor_process_handle_destroy(mp->process_handle, 1); + mp->process_handle = NULL; + + /* destroy all its old transports. we no longer use them. */ + SMARTLIST_FOREACH_BEGIN(mp->transports, const char *, t_name) { + t_tmp = transport_get_by_name(t_name); + if (t_tmp) + t_tmp->marked_for_removal = 1; + } SMARTLIST_FOREACH_END(t_name); + sweep_transport_list(); + + /* free the transport names in mp->transports */ + SMARTLIST_FOREACH(mp->transports, char *, t_name, tor_free(t_name)); + smartlist_clear(mp->transports); + + /* flag it as an infant proxy so that it gets launched on next tick */ + mp->conf_state = PT_PROTO_INFANT; + unconfigured_proxies_n++; +} + +/** Launch managed proxy <b>mp</b>. */ +static int +launch_managed_proxy(managed_proxy_t *mp) +{ + int retval; + + process_environment_t *env = create_managed_proxy_environment(mp); + +#ifdef _WIN32 + /* Passing NULL as lpApplicationName makes Windows search for the .exe */ + retval = tor_spawn_background(NULL, + (const char **)mp->argv, + env, + &mp->process_handle); +#else + retval = tor_spawn_background(mp->argv[0], + (const char **)mp->argv, + env, + &mp->process_handle); +#endif + + process_environment_free(env); + + if (retval == PROCESS_STATUS_ERROR) { + log_warn(LD_GENERAL, "Managed proxy at '%s' failed at launch.", + mp->argv[0]); + return -1; + } + + log_info(LD_CONFIG, "Managed proxy at '%s' has spawned with PID '%d'.", + mp->argv[0], tor_process_get_pid(mp->process_handle)); + + mp->conf_state = PT_PROTO_LAUNCHED; + + 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) +{ + smartlist_t *tmp = smartlist_new(); + + log_debug(LD_CONFIG, "Configuring remaining managed proxies (%d)!", + unconfigured_proxies_n); + + /* Iterate over tmp, not managed_proxy_list, since configure_proxy can + * remove elements from managed_proxy_list. */ + smartlist_add_all(tmp, managed_proxy_list); + + assert_unconfigured_count_ok(); + + SMARTLIST_FOREACH_BEGIN(tmp, managed_proxy_t *, mp) { + tor_assert(mp->conf_state != PT_PROTO_BROKEN || + mp->conf_state != PT_PROTO_FAILED_LAUNCH); + + if (mp->got_hup) { + mp->got_hup = 0; + + /* This proxy is marked by a SIGHUP. Check whether we need to + restart it. */ + if (proxy_needs_restart(mp)) { + log_info(LD_GENERAL, "Preparing managed proxy '%s' for restart.", + mp->argv[0]); + proxy_prepare_for_restart(mp); + } else { /* it doesn't need to be restarted. */ + log_info(LD_GENERAL, "Nothing changed for managed proxy '%s' after " + "HUP: not restarting.", mp->argv[0]); + } + + continue; + } + + /* If the proxy is not fully configured, try to configure it + futher. */ + if (!proxy_configuration_finished(mp)) + configure_proxy(mp); + + } SMARTLIST_FOREACH_END(mp); + + smartlist_free(tmp); + check_if_restarts_needed = 0; + assert_unconfigured_count_ok(); +} + +#ifdef _WIN32 + +/** Attempt to continue configuring managed proxy <b>mp</b>. */ +static void +configure_proxy(managed_proxy_t *mp) +{ + int pos; + char stdout_buf[200]; + smartlist_t *lines = NULL; + + /* if we haven't launched the proxy yet, do it now */ + if (mp->conf_state == PT_PROTO_INFANT) { + if (launch_managed_proxy(mp) < 0) { /* launch fail */ + mp->conf_state = PT_PROTO_FAILED_LAUNCH; + handle_finished_proxy(mp); + } + return; + } + + tor_assert(mp->conf_state != PT_PROTO_INFANT); + tor_assert(mp->process_handle); + + pos = tor_read_all_handle(tor_process_get_stdout_pipe(mp->process_handle), + stdout_buf, sizeof(stdout_buf) - 1, NULL); + if (pos < 0) { + log_notice(LD_GENERAL, "Failed to read data from managed proxy '%s'.", + mp->argv[0]); + mp->conf_state = PT_PROTO_BROKEN; + goto done; + } + + if (pos == 0) /* proxy has nothing interesting to say. */ + return; + + /* End with a null even if there isn't a \r\n at the end */ + /* TODO: What if this is a partial line? */ + stdout_buf[pos] = '\0'; + + /* Split up the buffer */ + lines = smartlist_new(); + tor_split_lines(lines, stdout_buf, pos); + + /* Handle lines. */ + SMARTLIST_FOREACH_BEGIN(lines, const char *, line) { + handle_proxy_line(line, mp); + if (proxy_configuration_finished(mp)) + goto done; + } SMARTLIST_FOREACH_END(line); + + done: + /* if the proxy finished configuring, exit the loop. */ + if (proxy_configuration_finished(mp)) + handle_finished_proxy(mp); + + if (lines) + smartlist_free(lines); +} + +#else /* _WIN32 */ + +/** Attempt to continue configuring managed proxy <b>mp</b>. */ +static void +configure_proxy(managed_proxy_t *mp) +{ + enum stream_status r; + char stdout_buf[200]; + + /* if we haven't launched the proxy yet, do it now */ + if (mp->conf_state == PT_PROTO_INFANT) { + if (launch_managed_proxy(mp) < 0) { /* launch fail */ + mp->conf_state = PT_PROTO_FAILED_LAUNCH; + handle_finished_proxy(mp); + } + return; + } + + tor_assert(mp->conf_state != PT_PROTO_INFANT); + tor_assert(mp->process_handle); + + while (1) { + r = get_string_from_pipe(tor_process_get_stdout_pipe(mp->process_handle), + stdout_buf, sizeof(stdout_buf) - 1); + + if (r == IO_STREAM_OKAY) { /* got a line; handle it! */ + handle_proxy_line((const char *)stdout_buf, mp); + } else if (r == IO_STREAM_EAGAIN) { /* check back later */ + return; + } else if (r == IO_STREAM_CLOSED || r == IO_STREAM_TERM) { /* snap! */ + log_warn(LD_GENERAL, "Our communication channel with the managed proxy " + "'%s' closed. Most probably application stopped running.", + mp->argv[0]); + mp->conf_state = PT_PROTO_BROKEN; + } else { /* unknown stream status */ + log_warn(LD_BUG, "Unknown stream status '%d' while configuring managed " + "proxy '%s'.", (int)r, mp->argv[0]); + } + + /* if the proxy finished configuring, exit the loop. */ + if (proxy_configuration_finished(mp)) { + handle_finished_proxy(mp); + return; + } + } +} + +#endif /* _WIN32 */ + +/** Register server managed proxy <b>mp</b> transports to state */ +static void +register_server_proxy(managed_proxy_t *mp) +{ + /* After we register this proxy's transports, we switch its + mp->transports to a list containing strings of its transport + names. (See transports.h) */ + smartlist_t *sm_tmp = smartlist_new(); + + tor_assert(mp->conf_state != PT_PROTO_COMPLETED); + SMARTLIST_FOREACH_BEGIN(mp->transports, transport_t *, t) { + save_transport_to_state(t->name, &t->addr, t->port); + log_notice(LD_GENERAL, "Registered server transport '%s' at '%s:%d'", + t->name, fmt_addr(&t->addr), (int)t->port); + smartlist_add(sm_tmp, tor_strdup(t->name)); + } SMARTLIST_FOREACH_END(t); + + /* Since server proxies don't register their transports in the + circuitbuild.c subsystem, it's our duty to free them when we + switch mp->transports to strings. */ + SMARTLIST_FOREACH(mp->transports, transport_t *, t, transport_free(t)); + smartlist_free(mp->transports); + + mp->transports = sm_tmp; +} + +/** Register all the transports supported by client managed proxy + * <b>mp</b> to the bridge subsystem. */ +static void +register_client_proxy(managed_proxy_t *mp) +{ + int r; + /* After we register this proxy's transports, we switch its + mp->transports to a list containing strings of its transport + names. (See transports.h) */ + smartlist_t *sm_tmp = smartlist_new(); + + tor_assert(mp->conf_state != PT_PROTO_COMPLETED); + SMARTLIST_FOREACH_BEGIN(mp->transports, transport_t *, t) { + r = transport_add(t); + switch (r) { + case -1: + log_notice(LD_GENERAL, "Could not add transport %s. Skipping.", t->name); + transport_free(t); + break; + case 0: + log_info(LD_GENERAL, "Succesfully registered transport %s", t->name); + smartlist_add(sm_tmp, tor_strdup(t->name)); + break; + case 1: + log_info(LD_GENERAL, "Succesfully registered transport %s", t->name); + smartlist_add(sm_tmp, tor_strdup(t->name)); + transport_free(t); + break; + } + } SMARTLIST_FOREACH_END(t); + + smartlist_free(mp->transports); + mp->transports = sm_tmp; +} + +/** Register the transports of managed proxy <b>mp</b>. */ +static INLINE void +register_proxy(managed_proxy_t *mp) +{ + if (mp->is_server) + register_server_proxy(mp); + else + register_client_proxy(mp); +} + +/** Free memory allocated by managed proxy <b>mp</b>. */ +static void +managed_proxy_destroy(managed_proxy_t *mp, + int also_terminate_process) +{ + if (mp->conf_state != PT_PROTO_COMPLETED) + SMARTLIST_FOREACH(mp->transports, transport_t *, t, transport_free(t)); + else + SMARTLIST_FOREACH(mp->transports, char *, t_name, tor_free(t_name)); + + /* free the transports smartlist */ + smartlist_free(mp->transports); + + /* free the transports_to_launch smartlist */ + SMARTLIST_FOREACH(mp->transports_to_launch, char *, t, tor_free(t)); + smartlist_free(mp->transports_to_launch); + + /* remove it from the list of managed proxies */ + smartlist_remove(managed_proxy_list, mp); + + /* free the argv */ + free_execve_args(mp->argv); + + tor_process_handle_destroy(mp->process_handle, also_terminate_process); + mp->process_handle = NULL; + + tor_free(mp); +} + +/** 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); /* annihilate it. */ + break; + case PT_PROTO_FAILED_LAUNCH: /* if it failed before launching: */ + managed_proxy_destroy(mp, 0); /* destroy it but don't terminate */ + break; + case PT_PROTO_CONFIGURED: /* if configured correctly: */ + register_proxy(mp); /* register its transports */ + mp->conf_state = PT_PROTO_COMPLETED; /* and mark it as completed. */ + break; + case PT_PROTO_INFANT: + case PT_PROTO_LAUNCHED: + case PT_PROTO_ACCEPTING_METHODS: + case PT_PROTO_COMPLETED: + default: + log_warn(LD_CONFIG, "Unexpected state '%d' of managed proxy '%s'.", + (int)mp->conf_state, mp->argv[0]); + tor_assert(0); + } + + unconfigured_proxies_n--; + tor_assert(unconfigured_proxies_n >= 0); +} + +/** Return true if the configuration of the managed proxy <b>mp</b> is + finished. */ +static INLINE int +proxy_configuration_finished(const managed_proxy_t *mp) +{ + return (mp->conf_state == PT_PROTO_CONFIGURED || + mp->conf_state == PT_PROTO_BROKEN || + mp->conf_state == PT_PROTO_FAILED_LAUNCH); +} + +/** This function is called when a proxy sends an {S,C}METHODS DONE message. */ +static void +handle_methods_done(const managed_proxy_t *mp) +{ + tor_assert(mp->transports); + + if (smartlist_len(mp->transports) == 0) + log_notice(LD_GENERAL, "Managed proxy '%s' was spawned successfully, " + "but it didn't launch any pluggable transport listeners!", + mp->argv[0]); + + log_info(LD_CONFIG, "%s managed proxy '%s' configuration completed!", + mp->is_server ? "Server" : "Client", + mp->argv[0]); +} + +/** Handle a configuration protocol <b>line</b> received from a + * managed proxy <b>mp</b>. */ +void +handle_proxy_line(const char *line, managed_proxy_t *mp) +{ + log_info(LD_GENERAL, "Got a line from managed proxy '%s': (%s)", + mp->argv[0], line); + + if (!strcmpstart(line, PROTO_ENV_ERROR)) { + if (mp->conf_state != PT_PROTO_LAUNCHED) + goto err; + + parse_env_error(line); + goto err; + } else if (!strcmpstart(line, PROTO_NEG_FAIL)) { + if (mp->conf_state != PT_PROTO_LAUNCHED) + goto err; + + log_warn(LD_CONFIG, "Managed proxy could not pick a " + "configuration protocol version."); + goto err; + } else if (!strcmpstart(line, PROTO_NEG_SUCCESS)) { + if (mp->conf_state != PT_PROTO_LAUNCHED) + 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 (!strcmpstart(line, PROTO_CMETHODS_DONE)) { + if (mp->conf_state != PT_PROTO_ACCEPTING_METHODS) + goto err; + + handle_methods_done(mp); + + mp->conf_state = PT_PROTO_CONFIGURED; + return; + } else if (!strcmpstart(line, PROTO_SMETHODS_DONE)) { + if (mp->conf_state != PT_PROTO_ACCEPTING_METHODS) + goto err; + + handle_methods_done(mp); + + mp->conf_state = PT_PROTO_CONFIGURED; + return; + } else if (!strcmpstart(line, PROTO_CMETHOD_ERROR)) { + if (mp->conf_state != PT_PROTO_ACCEPTING_METHODS) + goto err; + + parse_client_method_error(line); + goto err; + } else if (!strcmpstart(line, PROTO_SMETHOD_ERROR)) { + if (mp->conf_state != PT_PROTO_ACCEPTING_METHODS) + goto err; + + parse_server_method_error(line); + goto err; + } else if (!strcmpstart(line, PROTO_CMETHOD)) { + if (mp->conf_state != PT_PROTO_ACCEPTING_METHODS) + goto err; + + if (parse_cmethod_line(line, mp) < 0) + goto err; + + return; + } else if (!strcmpstart(line, PROTO_SMETHOD)) { + if (mp->conf_state != PT_PROTO_ACCEPTING_METHODS) + goto err; + + if (parse_smethod_line(line, mp) < 0) + goto err; + + return; + } else if (!strcmpstart(line, SPAWN_ERROR_MESSAGE)) { + /* managed proxy launch failed: parse error message to learn why. */ + int retval, child_state, saved_errno; + retval = tor_sscanf(line, SPAWN_ERROR_MESSAGE "%x/%x", + &child_state, &saved_errno); + if (retval == 2) { + log_warn(LD_GENERAL, + "Could not launch managed proxy executable at '%s' ('%s').", + mp->argv[0], strerror(saved_errno)); + } else { /* failed to parse error message */ + log_warn(LD_GENERAL,"Could not launch managed proxy executable at '%s'.", + mp->argv[0]); + } + + mp->conf_state = PT_PROTO_FAILED_LAUNCH; + return; + } + + log_notice(LD_GENERAL, "Unknown line received by managed proxy (%s).", line); + return; + + err: + mp->conf_state = PT_PROTO_BROKEN; + log_warn(LD_CONFIG, "Managed proxy at '%s' failed the configuration protocol" + " and will be destroyed.", mp->argv[0]); +} + +/** Parses an ENV-ERROR <b>line</b> and warns the user accordingly. */ +void +parse_env_error(const char *line) +{ + /* (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_notice(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(const char *line, managed_proxy_t *mp) +{ + 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)) { /* hardcoded temp */ + log_warn(LD_CONFIG, "Managed proxy tried to negotiate on 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(const 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> and if well-formed it registers the + * new transport in <b>mp</b>. */ +int +parse_smethod_line(const char *line, managed_proxy_t *mp) +{ + int r; + smartlist_t *items = NULL; + + char *method_name=NULL; + + char *addrport=NULL; + tor_addr_t tor_addr; + char *address=NULL; + uint16_t port = 0; + + transport_t *transport=NULL; + + items = smartlist_new(); + 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); + if (!string_is_C_identifier(method_name)) { + log_warn(LD_CONFIG, "Transport name is not a C identifier (%s).", + method_name); + goto err; + } + + addrport = smartlist_get(items, 2); + if (tor_addr_port_split(LOG_PROTOCOL_WARN, addrport, &address, &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; + } + + if (tor_addr_parse(&tor_addr, address) < 0) { + log_warn(LD_CONFIG, "Error parsing transport address '%s'", address); + goto err; + } + + transport = transport_new(&tor_addr, port, method_name, PROXY_NONE); + if (!transport) + goto err; + + smartlist_add(mp->transports, transport); + + /* For now, notify the user so that he knows where the server + transport is listening. */ + log_info(LD_CONFIG, "Server transport %s at %s:%d.", + method_name, address, (int)port); + + r=0; + goto done; + + err: + r = -1; + + done: + SMARTLIST_FOREACH(items, char*, s, tor_free(s)); + smartlist_free(items); + tor_free(address); + 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(const 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 tor_addr; + char *address=NULL; + uint16_t port = 0; + + transport_t *transport=NULL; + + items = smartlist_new(); + 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); + if (!string_is_C_identifier(method_name)) { + log_warn(LD_CONFIG, "Transport name is not a C identifier (%s).", + method_name); + goto err; + } + + 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_split(LOG_PROTOCOL_WARN, addrport, &address, &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; + } + + if (tor_addr_parse(&tor_addr, address) < 0) { + log_warn(LD_CONFIG, "Error parsing transport address '%s'", address); + goto err; + } + + transport = transport_new(&tor_addr, port, method_name, socks_ver); + if (!transport) + goto err; + + smartlist_add(mp->transports, transport); + + log_info(LD_CONFIG, "Transport %s at %s:%d with SOCKS %d. " + "Attached to managed proxy.", + method_name, address, (int)port, socks_ver); + + r=0; + goto done; + + err: + r = -1; + + done: + SMARTLIST_FOREACH(items, char*, s, tor_free(s)); + smartlist_free(items); + tor_free(address); + return r; +} + +/** Return the string that tor should place in TOR_PT_SERVER_BINDADDR + * while configuring the server managed proxy in <b>mp</b>. The + * string is stored in the heap, and it's the the responsibility of + * the caller to deallocate it after its use. */ +static char * +get_bindaddr_for_server_proxy(const managed_proxy_t *mp) +{ + char *bindaddr_result = NULL; + char *bindaddr_tmp = NULL; + smartlist_t *string_tmp = smartlist_new(); + + tor_assert(mp->is_server); + + SMARTLIST_FOREACH_BEGIN(mp->transports_to_launch, char *, t) { + bindaddr_tmp = get_stored_bindaddr_for_server_transport(t); + + smartlist_add_asprintf(string_tmp, "%s-%s", t, bindaddr_tmp); + + tor_free(bindaddr_tmp); + } SMARTLIST_FOREACH_END(t); + + bindaddr_result = smartlist_join_strings(string_tmp, ",", 0, NULL); + + SMARTLIST_FOREACH(string_tmp, char *, t, tor_free(t)); + smartlist_free(string_tmp); + + return bindaddr_result; +} + +/** Return a newly allocated process_environment_t * for <b>mp</b>'s + * process. */ +static process_environment_t * +create_managed_proxy_environment(const managed_proxy_t *mp) +{ + /* Environment variables to be added to or set in mp's environment. */ + smartlist_t *envs = smartlist_new(); + /* XXXX The next time someone touches this code, shorten the name of + * set_environment_variable_in_smartlist, add a + * set_env_var_in_smartlist_asprintf function, and get rid of the + * silly extra envs smartlist. */ + + /* The final environment to be passed to mp. */ + smartlist_t *merged_env_vars = get_current_process_environment_variables(); + + process_environment_t *env; + + { + char *state_tmp = get_datadir_fname("pt_state/"); /* XXX temp */ + smartlist_add_asprintf(envs, "TOR_PT_STATE_LOCATION=%s", state_tmp); + tor_free(state_tmp); + } + + smartlist_add(envs, tor_strdup("TOR_PT_MANAGED_TRANSPORT_VER=1")); + + { + char *transports_to_launch = + smartlist_join_strings(mp->transports_to_launch, ",", 0, NULL); + + smartlist_add_asprintf(envs, + mp->is_server ? + "TOR_PT_SERVER_TRANSPORTS=%s" : + "TOR_PT_CLIENT_TRANSPORTS=%s", + transports_to_launch); + + tor_free(transports_to_launch); + } + + if (mp->is_server) { + { + char *orport_tmp = + get_first_listener_addrport_string(CONN_TYPE_OR_LISTENER); + smartlist_add_asprintf(envs, "TOR_PT_ORPORT=%s", orport_tmp); + tor_free(orport_tmp); + } + + { + char *bindaddr_tmp = get_bindaddr_for_server_proxy(mp); + smartlist_add_asprintf(envs, "TOR_PT_SERVER_BINDADDR=%s", bindaddr_tmp); + tor_free(bindaddr_tmp); + } + + /* XXX024 Remove the '=' here once versions of obfsproxy which + * assert that this env var exists are sufficiently dead. + * + * (If we remove this line entirely, some joker will stick this + * variable in Tor's environment and crash PTs that try to parse + * it even when not run in server mode.) */ + smartlist_add(envs, tor_strdup("TOR_PT_EXTENDED_SERVER_PORT=")); + } + + SMARTLIST_FOREACH_BEGIN(envs, const char *, env_var) { + set_environment_variable_in_smartlist(merged_env_vars, env_var, + _tor_free, 1); + } SMARTLIST_FOREACH_END(env_var); + + env = process_environment_make(merged_env_vars); + + smartlist_free(envs); + + SMARTLIST_FOREACH(merged_env_vars, void *, x, tor_free(x)); + smartlist_free(merged_env_vars); + + return env; +} + +/** Create and return a new managed proxy for <b>transport</b> using + * <b>proxy_argv</b>. Also, add it to the global managed proxy list. If + * <b>is_server</b> is true, it's a server managed proxy. Takes ownership of + * <b>proxy_argv</b>. + * + * Requires that proxy_argv have at least one element. */ +static managed_proxy_t * +managed_proxy_create(const smartlist_t *transport_list, + char **proxy_argv, int is_server) +{ + managed_proxy_t *mp = tor_malloc_zero(sizeof(managed_proxy_t)); + mp->conf_state = PT_PROTO_INFANT; + mp->is_server = is_server; + mp->argv = proxy_argv; + mp->transports = smartlist_new(); + + mp->transports_to_launch = smartlist_new(); + SMARTLIST_FOREACH(transport_list, const char *, transport, + add_transport_to_proxy(transport, mp)); + + /* register the managed proxy */ + if (!managed_proxy_list) + managed_proxy_list = smartlist_new(); + smartlist_add(managed_proxy_list, mp); + unconfigured_proxies_n++; + + assert_unconfigured_count_ok(); + + return mp; +} + +/** Register proxy with <b>proxy_argv</b>, supporting transports in + * <b>transport_list</b>, to the managed proxy subsystem. + * If <b>is_server</b> is true, then the proxy is a server proxy. + * + * Takes ownership of proxy_argv. + * + * Requires that proxy_argv be a NULL-terminated array of command-line + * elements, containing at least one element. + **/ +void +pt_kickstart_proxy(const smartlist_t *transport_list, + char **proxy_argv, int is_server) +{ + managed_proxy_t *mp=NULL; + transport_t *old_transport = NULL; + + if (!proxy_argv || !proxy_argv[0]) { + return; + } + + mp = get_managed_proxy_by_argv_and_type(proxy_argv, is_server); + + if (!mp) { /* we haven't seen this proxy before */ + managed_proxy_create(transport_list, proxy_argv, is_server); + + } else { /* known proxy. add its transport to its transport list */ + if (mp->got_hup) { + /* If the managed proxy we found is marked by a SIGHUP, it means + that it's not useless and should be kept. If it's marked for + removal, unmark it and increase the unconfigured proxies so + that we try to restart it if we need to. Afterwards, check if + a transport_t for 'transport' used to exist before the SIGHUP + and make sure it doesn't get deleted because we might reuse + it. */ + if (mp->marked_for_removal) { + mp->marked_for_removal = 0; + check_if_restarts_needed = 1; + } + + SMARTLIST_FOREACH_BEGIN(transport_list, const char *, transport) { + old_transport = transport_get_by_name(transport); + if (old_transport) + old_transport->marked_for_removal = 0; + } SMARTLIST_FOREACH_END(transport); + } + + SMARTLIST_FOREACH(transport_list, const char *, transport, + add_transport_to_proxy(transport, mp)); + free_execve_args(proxy_argv); + } +} + +/** Frees the array of pointers in <b>arg</b> used as arguments to + execve(2). */ +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); +} + +/** Tor will read its config. + * Prepare the managed proxy list so that proxies not used in the new + * config will shutdown, and proxies that need to spawn different + * transports will do so. */ +void +pt_prepare_proxy_list_for_config_read(void) +{ + if (!managed_proxy_list) + return; + + assert_unconfigured_count_ok(); + SMARTLIST_FOREACH_BEGIN(managed_proxy_list, managed_proxy_t *, mp) { + /* Destroy unconfigured proxies. */ + if (mp->conf_state != PT_PROTO_COMPLETED) { + SMARTLIST_DEL_CURRENT(managed_proxy_list, mp); + managed_proxy_destroy(mp, 1); + unconfigured_proxies_n--; + continue; + } + + tor_assert(mp->conf_state == PT_PROTO_COMPLETED); + + mp->marked_for_removal = 1; + mp->got_hup = 1; + SMARTLIST_FOREACH(mp->transports_to_launch, char *, t, tor_free(t)); + smartlist_clear(mp->transports_to_launch); + } SMARTLIST_FOREACH_END(mp); + + assert_unconfigured_count_ok(); + + tor_assert(unconfigured_proxies_n == 0); +} + +/** The tor config was read. + * Destroy all managed proxies that were marked by a previous call to + * prepare_proxy_list_for_config_read() and are not used by the new + * config. */ +void +sweep_proxy_list(void) +{ + if (!managed_proxy_list) + return; + assert_unconfigured_count_ok(); + SMARTLIST_FOREACH_BEGIN(managed_proxy_list, managed_proxy_t *, mp) { + if (mp->marked_for_removal) { + SMARTLIST_DEL_CURRENT(managed_proxy_list, mp); + managed_proxy_destroy(mp, 1); + } + } SMARTLIST_FOREACH_END(mp); + assert_unconfigured_count_ok(); +} + +/** Release all storage held by the pluggable transports subsystem. */ +void +pt_free_all(void) +{ + if (managed_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(managed_proxy_list, managed_proxy_t *, mp, { + SMARTLIST_DEL_CURRENT(managed_proxy_list, mp); + managed_proxy_destroy(mp, 1); + }); + + smartlist_free(managed_proxy_list); + managed_proxy_list=NULL; + } +} + |