307 temporary redirect

/* * (C) 2013 by Christian Hesse * * This software may be used and distributed according to the terms * of the GNU General Public License, incorporated herein by reference. * * This is an example code skeleton provided by vim-skeleton. */ #include #include #include #include #include #include #include #include #include #include #include #include #include #define PAGE307 "307 temporary redirect" \ "307 temporary redirect: " \ "%s" #define PAGE404 "404 Not Found" \ "404 Not Found: %s" #define PORT 7077 #define SERVICE "_pacserve._tcp" #define BADTIME 60 * 10 /* hosts */ struct hosts { /* host name */ char * host; /* http port */ uint16_t port; /* unix timestamp of last bad request */ __time_t bad; /* true if host is offline */ uint8_t offline; /* pointer to next struct element */ struct hosts * next; }; /* global variables */ struct hosts * hosts = NULL; static AvahiSimplePoll *simple_poll = NULL; /*** resolve_callback_new *** * Called whenever a service has been resolved successfully or timed out */ static void resolve_callback_new(AvahiServiceResolver *r, AVAHI_GCC_UNUSED AvahiIfIndex interface, AVAHI_GCC_UNUSED AvahiProtocol protocol, AvahiResolverEvent event, const char *name, const char *type, const char *domain, const char *host, const AvahiAddress *address, AVAHI_GCC_UNUSED uint16_t port, AVAHI_GCC_UNUSED AvahiStringList *txt, AVAHI_GCC_UNUSED AvahiLookupResultFlags flags, AVAHI_GCC_UNUSED void* userdata) { struct hosts * tmphosts = hosts; assert(r); switch (event) { case AVAHI_RESOLVER_FAILURE: fprintf(stderr, "(Resolver) Failed to resolve service '%s' of type '%s' in domain '%s': %s\n", name, type, domain, avahi_strerror(avahi_client_errno(avahi_service_resolver_get_client(r)))); break; case AVAHI_RESOLVER_FOUND: { while (tmphosts->host != NULL) { if (strcmp(tmphosts->host, host) == 0) { # if defined DEBUG printf("Host is already in the list: %s\n", host); # endif tmphosts->offline = 0; goto out; } tmphosts = tmphosts->next; } printf("Adding host: %s, port %d\n", host, port); tmphosts->host = strdup(host); tmphosts->port = port; tmphosts->bad = 0; tmphosts->offline = 0; tmphosts->next = realloc(tmphosts->next, sizeof(struct hosts)); tmphosts = tmphosts->next; tmphosts->host = NULL; tmphosts->next = NULL; break; } } out: avahi_service_resolver_free(r); } /*** resolve_callback_remove *** * Called whenever a service has been resolved successfully or timed out */ static void resolve_callback_remove(AvahiServiceResolver *r, AVAHI_GCC_UNUSED AvahiIfIndex interface, AVAHI_GCC_UNUSED AvahiProtocol protocol, AvahiResolverEvent event, const char *name, const char *type, const char *domain, const char *host, const AvahiAddress *address, AVAHI_GCC_UNUSED uint16_t port, AVAHI_GCC_UNUSED AvahiStringList *txt, AVAHI_GCC_UNUSED AvahiLookupResultFlags flags, AVAHI_GCC_UNUSED void* userdata) { struct hosts * tmphosts = hosts; assert(r); switch (event) { case AVAHI_RESOLVER_FAILURE: fprintf(stderr, "(Resolver) Failed to resolve service '%s' of type '%s' in domain '%s': %s\n", name, type, domain, avahi_strerror(avahi_client_errno(avahi_service_resolver_get_client(r)))); break; case AVAHI_RESOLVER_FOUND: { while (tmphosts->host != NULL) { if (strcmp(tmphosts->host, host) == 0) { printf("Marking host offline: %s\n", host); tmphosts->offline = 1; goto out; } tmphosts = tmphosts->next; } break; } } out: avahi_service_resolver_free(r); } /*** browse_callback *** * Called whenever a new services becomes available on the LAN or is removed from the LAN */ static void browse_callback(AvahiServiceBrowser *b, AvahiIfIndex interface, AvahiProtocol protocol, AvahiBrowserEvent event, const char *name, const char *type, const char *domain, AVAHI_GCC_UNUSED AvahiLookupResultFlags flags, void* userdata) { AvahiClient *c = userdata; assert(b); switch (event) { case AVAHI_BROWSER_FAILURE: fprintf(stderr, "(Browser) %s\n", avahi_strerror(avahi_client_errno(avahi_service_browser_get_client(b)))); avahi_simple_poll_quit(simple_poll); return; case AVAHI_BROWSER_NEW: # if defined DEBUG fprintf(stderr, "(Browser) NEW: service '%s' of type '%s' in domain '%s'\n", name, type, domain); # endif /* We ignore the returned resolver object. In the callback * function we free it. If the server is terminated before * the callback function is called the server will free * the resolver for us. */ if (avahi_service_resolver_new(c, interface, protocol, name, type, domain, AVAHI_PROTO_UNSPEC, 0, resolve_callback_new, c) == NULL) fprintf(stderr, "Failed to resolve service '%s': %s\n", name, avahi_strerror(avahi_client_errno(c))); break; case AVAHI_BROWSER_REMOVE: # if defined DEBUG fprintf(stderr, "(Browser) REMOVE: service '%s' of type '%s' in domain '%s'\n", name, type, domain); # endif if (avahi_service_resolver_new(c, interface, protocol, name, type, domain, AVAHI_PROTO_UNSPEC, 0, resolve_callback_remove, c) == NULL) fprintf(stderr, "Failed to resolve service '%s': %s\n", name, avahi_strerror(avahi_client_errno(c))); break; case AVAHI_BROWSER_ALL_FOR_NOW: case AVAHI_BROWSER_CACHE_EXHAUSTED: break; } } /*** client_callback ***/ static void client_callback(AvahiClient *c, AvahiClientState state, AVAHI_GCC_UNUSED void * userdata) { assert(c); if (state == AVAHI_CLIENT_FAILURE) { fprintf(stderr, "Server connection failure: %s\n", avahi_strerror(avahi_client_errno(c))); avahi_simple_poll_quit(simple_poll); } } /*** get_http_code ***/ int get_http_code(const char * host, const uint16_t port, const char * url) { CURL *curl; CURLcode res; unsigned int http_code; curl_global_init(CURL_GLOBAL_ALL); if ((curl = curl_easy_init()) != NULL) { curl_easy_setopt(curl, CURLOPT_URL, url); /* example.com is redirected, so we tell libcurl to follow redirection */ curl_easy_setopt(curl, CURLOPT_FOLLOWLOCATION, 1L); /* set user agent */ curl_easy_setopt(curl, CURLOPT_USERAGENT, "pacredir/" VERSION); /* do not receive body */ curl_easy_setopt(curl, CURLOPT_NOBODY, 1); /* set connection timeout to 2 seconds * if the host needs longer we do not want to use it anyway ;) */ curl_easy_setopt(curl, CURLOPT_CONNECTTIMEOUT, 2); /* get it! */ if (curl_easy_perform(curl) != CURLE_OK) { fprintf(stderr, "Could not connect to server %s on port %d.\n", host, port); return -1; } if ((res = curl_easy_getinfo(curl, CURLINFO_RESPONSE_CODE, &http_code)) != CURLE_OK) { fprintf(stderr, "curl_easy_getinfo() failed: %s\n", curl_easy_strerror(res)); return -1; } /* always cleanup */ curl_easy_cleanup(curl); } /* we're done with libcurl, so clean it up */ curl_global_cleanup(); return http_code; } /*** ahc_echo *** * called whenever a http request is received */ static int ahc_echo(void * cls, struct MHD_Connection * connection, const char * uri, const char * method, const char * version, const char * upload_data, size_t * upload_data_size, void ** ptr) { static int dummy; struct MHD_Response * response; int ret; struct hosts * tmphosts = hosts; char * url = NULL, * page; const char * basename; int http_code = 0; struct timeval tv; /* we want to filename, not the path */ basename = uri; while (strstr(basename, "/") != NULL) basename = strstr(basename, "/") + 1; if (strcmp(method, "GET") != 0) return MHD_NO; /* unexpected method */ if (&dummy != *ptr) { /* The first time only the headers are valid, * do not respond in the first round... */ *ptr = &dummy; return MHD_YES; } if (*upload_data_size != 0) return MHD_NO; /* upload data in a GET!? */ /* clear context pointer */ *ptr = NULL; /* do not process db requests */ /* TODO: do some timestamp magic to find suitable db files */ if (strcmp(basename + strlen(basename) - 3, ".db") == 0) { # if defined DEBUG printf("Not precessing db file request for %s\n", basename); # endif } else { /* try to find a server */ while (tmphosts->host != NULL) { gettimeofday(&tv, NULL); /* skip host if offline or had a bad request within last BADTIME seconds */ if (tmphosts->offline == 1 || tmphosts->bad + BADTIME > tv.tv_sec) { tmphosts = tmphosts->next; continue; } url = malloc(10 + strlen(tmphosts->host) + 5 + strlen(basename)); sprintf(url, "http://%s:%d/%s", tmphosts->host, tmphosts->port, basename); printf("Trying %s\n", url); if ((http_code = get_http_code(tmphosts->host, tmphosts->port, url)) == MHD_HTTP_OK) break; else if (http_code == -1) tmphosts->bad = tv.tv_sec; tmphosts = tmphosts->next; } } /* give response */ if (http_code == MHD_HTTP_OK) { printf("Redirecting to %s\n", url); page = malloc(strlen(PAGE307) + strlen(url) + strlen(basename) + 1); sprintf(page, PAGE307, url, basename); response = MHD_create_response_from_data(strlen(url), (void*) url, MHD_NO, MHD_NO); ret = MHD_add_response_header(response, "Location", url); ret = MHD_queue_response(connection, MHD_HTTP_TEMPORARY_REDIRECT, response); } else { printf("File %s not found, giving up.\n", basename); page = malloc(strlen(PAGE404) + strlen(basename) + 1); sprintf(page, PAGE404, basename); response = MHD_create_response_from_data(strlen(page), (void*) page, MHD_NO, MHD_NO); ret = MHD_queue_response(connection, MHD_HTTP_NOT_FOUND, response); } MHD_destroy_response(response); free(page); if (url != NULL) free(url); return ret; } /*** sigterm_callback ***/ void sigterm_callback(int signal) { avahi_simple_poll_quit(simple_poll); } /*** sighup_callback ***/ void sighup_callback(int signal) { struct hosts * tmphosts = hosts; printf("Received SIGHUP, marking all hosts offline.\n"); while (tmphosts->host != NULL) { tmphosts->offline = 1; tmphosts = tmphosts->next; } } /*** main ***/ int main(int argc, char ** argv) { AvahiClient *client = NULL; AvahiServiceBrowser *sb = NULL; int error; int ret = 1; struct MHD_Daemon * mhd; struct hosts * tmphosts; printf("Starting pacredir/" VERSION "\n"); /* allocate first struct element as dummy */ hosts = malloc(sizeof(struct hosts)); hosts->host = NULL; hosts->port = 0; hosts->bad = 0; hosts->offline = 0; hosts->next = NULL; /* allocate main loop object */ if (!(simple_poll = avahi_simple_poll_new())) { fprintf(stderr, "Failed to create simple poll object.\n"); goto fail; } /* allocate a new client */ client = avahi_client_new(avahi_simple_poll_get(simple_poll), 0, client_callback, NULL, &error); /* check wether creating the client object succeeded */ if (!client) { fprintf(stderr, "Failed to create client: %s\n", avahi_strerror(error)); goto fail; } /* create the service browser */ if (!(sb = avahi_service_browser_new(client, AVAHI_IF_UNSPEC, AVAHI_PROTO_UNSPEC, SERVICE, NULL, 0, browse_callback, client))) { fprintf(stderr, "Failed to create service browser: %s\n", avahi_strerror(avahi_client_errno(client))); goto fail; } if ((mhd = MHD_start_daemon(MHD_USE_THREAD_PER_CONNECTION, PORT, NULL, NULL, &ahc_echo, NULL, MHD_OPTION_END)) == NULL) { fprintf(stderr, "Could not start daemon on port %d.\n", PORT); return EXIT_FAILURE; } /* register signal callbacks */ signal(SIGTERM, sigterm_callback); signal(SIGHUP, sighup_callback); /* run the main loop */ avahi_simple_poll_loop(simple_poll); MHD_stop_daemon(mhd); ret = EXIT_SUCCESS; fail: /* Cleanup things */ while(hosts->host != NULL) { free(hosts->host); tmphosts = hosts->next; free(hosts); hosts = tmphosts; } if (sb) avahi_service_browser_free(sb); if (client) avahi_client_free(client); if (simple_poll) avahi_simple_poll_free(simple_poll); return ret; } // vim: set syntax=c: