562 lines
13 KiB
C
562 lines
13 KiB
C
/*
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Copyright (c) 2014-2015, Nils Schneider <nils@nilsschneider.net>
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Copyright (c) 2015-2016, Matthias Schiffer <mschiffer@universe-factory.net>
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All rights reserved.
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Redistribution and use in source and binary forms, with or without
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modification, are permitted provided that the following conditions are met:
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1. Redistributions of source code must retain the above copyright notice,
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this list of conditions and the following disclaimer.
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2. Redistributions in binary form must reproduce the above copyright notice,
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this list of conditions and the following disclaimer in the documentation
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and/or other materials provided with the distribution.
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THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
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AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
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DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
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FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
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SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
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CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
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OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
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OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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#include "respondd.h"
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#include "miniz.c"
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#include <json-c/json.h>
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#include <alloca.h>
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#include <dirent.h>
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#include <dlfcn.h>
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#include <inttypes.h>
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#include <search.h>
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#include <stdbool.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <time.h>
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#include <unistd.h>
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#include <errno.h>
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#include <arpa/inet.h>
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#include <net/if.h>
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#include <netinet/in.h>
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#include <sys/types.h>
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#include <sys/socket.h>
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#define SCHEDULE_LEN 8
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#define REQUEST_MAXLEN 256
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struct provider_list {
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struct provider_list *next;
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char *name;
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respondd_provider provider;
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};
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struct request_type {
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// points to the corresponding provider_list for this request in the chained list
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struct provider_list *providers;
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struct json_object *cache;
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uint64_t cache_time;
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int64_t cache_timeout;
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};
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struct request_task {
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struct request_task *next;
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int64_t scheduled_time;
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struct sockaddr_storage client_addr;
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socklen_t client_addrlen;
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char request[REQUEST_MAXLEN];
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};
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struct request_schedule {
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int length;
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struct request_task *list_head;
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};
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static int64_t now;
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static struct hsearch_data htab;
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void process_request(int sock, char *input, struct sockaddr_in *addr, socklen_t addrlen);
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static struct json_object * merge_json(struct json_object *a, struct json_object *b);
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static void usage() {
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puts("Usage:");
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puts(" respondd -h");
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puts(" respondd [-p <port>] [-g <group> -i <if0> [-i <if1> ..]] [-d <dir>]");
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puts(" -p <int> port number to listen on");
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puts(" -g <ip6> multicast group, e.g. ff02::2:1001");
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puts(" -i <string> interface on which the group is joined");
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puts(" -d <string> data provider directory (default: current directory)");
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puts(" -h this help\n");
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}
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static void join_mcast(const int sock, const struct in6_addr addr, const char *iface) {
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struct ipv6_mreq mreq;
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mreq.ipv6mr_multiaddr = addr;
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mreq.ipv6mr_interface = if_nametoindex(iface);
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if (mreq.ipv6mr_interface == 0)
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goto error;
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if (setsockopt(sock, IPPROTO_IPV6, IPV6_JOIN_GROUP, &mreq, sizeof(mreq)) == -1)
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goto error;
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return;
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error:
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fprintf(stderr, "Could not join multicast group on %s: ", iface);
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perror(NULL);
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}
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static void update_time(void) {
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struct timespec tp;
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clock_gettime(CLOCK_MONOTONIC, &tp);
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now = (int64_t)tp.tv_sec * 1000 + tp.tv_nsec / 1000000;
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}
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/**
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* Merges two JSON objects
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*
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* On conflicts, object a will be preferred.
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*
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* Internally, this functions merges all entries from object a into object b,
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* so merging a small object a with a big object b is faster than vice-versa.
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*/
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static struct json_object * merge_json(struct json_object *a, struct json_object *b) {
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if (!json_object_is_type(a, json_type_object) || !json_object_is_type(b, json_type_object)) {
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json_object_put(b);
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return a;
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}
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json_object_object_foreach(a, key, val_a) {
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struct json_object *val_b;
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json_object_get(val_a);
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if (!json_object_object_get_ex(b, key, &val_b)) {
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json_object_object_add(b, key, val_a);
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continue;
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}
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json_object_get(val_b);
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json_object_object_add(b, key, merge_json(val_a, val_b));
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}
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json_object_put(a);
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return b;
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}
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static const struct respondd_provider_info * get_providers(const char *filename) {
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/*
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Prefix the filename with "./" to open the module in the current directory
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(dlopen looks in the standard library paths by default)
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*/
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char path[2 + strlen(filename) + 1];
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snprintf(path, sizeof(path), "./%s", filename);
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void *handle = dlopen(path, RTLD_NOW|RTLD_LOCAL);
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if (!handle)
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return NULL;
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const struct respondd_provider_info *ret = dlsym(handle, "respondd_providers");
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if (!ret) {
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dlclose(handle);
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return NULL;
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}
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return ret;
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}
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bool schedule_push_request(struct request_schedule *q, char* req,
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struct sockaddr *addr, socklen_t addrlen,
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int64_t scheduled_time) {
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if (q->length >= SCHEDULE_LEN)
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// schedule is full
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return false;
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struct request_task *new_task = malloc(sizeof(struct request_task));
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// store the request
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new_task->scheduled_time = scheduled_time;
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strcpy(new_task->request, req);
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memcpy(&new_task->client_addr, addr, addrlen);
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new_task->client_addrlen = addrlen;
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if (!q->list_head || q->list_head->scheduled_time > new_task->scheduled_time) {
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new_task->next = q->list_head;
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q->list_head = new_task;
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} else {
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struct request_task *t;
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for (t = q->list_head; t && t->next; t = t->next) {
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if (t->next->scheduled_time > new_task->scheduled_time) {
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break;
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}
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}
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new_task->next = t->next;
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t->next = new_task;
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}
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q->length++;
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return true;
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}
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// the returned task is already set as processed
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struct request_task * schedule_pop_request(struct request_schedule *q) {
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if (!q->list_head)
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// schedule is empty
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return NULL;
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if (q->list_head->scheduled_time > now) {
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// nothing to do yet
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return NULL;
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}
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struct request_task *result = q->list_head;
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q->list_head = q->list_head->next;
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q->length--;
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return result;
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}
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static void load_cache_time(struct request_type *r, const char *name) {
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r->cache = NULL;
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r->cache_time = 0;
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r->cache_timeout = now;
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char filename[strlen(name) + 7];
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snprintf(filename, sizeof(filename), "%s.cache", name);
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FILE *f = fopen(filename, "r");
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if (!f)
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return;
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fscanf(f, "%"SCNu64, &r->cache_time);
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fclose(f);
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}
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static void add_provider(const char *name, const struct respondd_provider_info *provider) {
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ENTRY key = {
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.key = (char *)provider->request,
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.data = NULL,
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};
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ENTRY *entry;
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if (!hsearch_r(key, FIND, &entry, &htab)) {
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struct request_type *r = malloc(sizeof(*r));
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r->providers = NULL;
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load_cache_time(r, provider->request);
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key.data = r;
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if (!hsearch_r(key, ENTER, &entry, &htab)) {
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perror("hsearch_r");
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exit(EXIT_FAILURE);
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}
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}
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struct request_type *r = entry->data;
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struct provider_list *pentry = malloc(sizeof(*pentry));
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pentry->name = strdup(name);
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pentry->provider = provider->provider;
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struct provider_list **pos;
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for (pos = &r->providers; *pos; pos = &(*pos)->next) {
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if (strcmp(pentry->name, (*pos)->name) < 0)
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break;
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}
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pentry->next = *pos;
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*pos = pentry;
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}
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static void load_providers(void) {
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update_time();
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/* Maximum number of request types, might be made configurable in the future */
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if (!hcreate_r(32, &htab)) {
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perror("hcreate_r");
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exit(EXIT_FAILURE);
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}
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DIR *dir = opendir(".");
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if (!dir) {
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perror("opendir");
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exit(EXIT_FAILURE);
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}
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struct dirent *ent;
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while ((ent = readdir(dir)) != NULL) {
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if (ent->d_name[0] == '.')
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continue;
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size_t len = strlen(ent->d_name);
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if (len < 4)
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continue;
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if (strcmp(&ent->d_name[len-3], ".so"))
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continue;
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const struct respondd_provider_info *providers = get_providers(ent->d_name);
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if (!providers)
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continue;
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for (; providers->request; providers++)
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add_provider(ent->d_name, providers);
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}
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closedir(dir);
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}
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static struct json_object * eval_providers(struct provider_list *providers) {
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struct json_object *ret = json_object_new_object();
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for (; providers; providers = providers->next)
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ret = merge_json(providers->provider(), ret);
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return ret;
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}
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static struct json_object * single_request(char *type) {
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ENTRY key = {
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.key = type,
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.data = NULL,
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};
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ENTRY *entry;
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if (!hsearch_r(key, FIND, &entry, &htab))
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return NULL;
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struct request_type *r = entry->data;
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if (r->cache_time && now < r->cache_timeout)
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return json_object_get(r->cache);
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struct json_object *ret = eval_providers(r->providers);
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if (r->cache_time) {
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if (r->cache)
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json_object_put(r->cache);
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r->cache = json_object_get(ret);
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r->cache_timeout = now + r->cache_time;
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}
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return ret;
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}
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static struct json_object * multi_request(char *types) {
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struct json_object *ret = json_object_new_object();
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char *type, *saveptr;
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for (type = strtok_r(types, " ", &saveptr); type; type = strtok_r(NULL, " ", &saveptr)) {
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struct json_object *sub = single_request(type);
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if (sub)
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json_object_object_add(ret, type, sub);
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}
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return ret;
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}
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static struct json_object * handle_request(char *request, bool *compress) {
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if (!*request)
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return NULL;
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if (!strncmp(request, "GET ", 4)) {
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*compress = true;
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return multi_request(request+4);
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}
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else {
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*compress = false;
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return single_request(request);
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}
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}
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// the return value indicates whether there was a request
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static bool accept_request(struct request_schedule *schedule, int sock) {
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char input[REQUEST_MAXLEN];
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ssize_t input_bytes;
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struct sockaddr_in6 addr;
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socklen_t addrlen = sizeof(addr);
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input_bytes = recvfrom(sock, input, sizeof(input)-1, 0, (struct sockaddr *)&addr, &addrlen);
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// Timeout
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if (input_bytes < 0 && errno == EWOULDBLOCK)
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return false;
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if (input_bytes < 0) {
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perror("recvfrom failed");
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exit(EXIT_FAILURE);
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}
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input[input_bytes] = 0;
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// TODO: only multicast requests should be scheduled in future
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schedule_push_request(schedule, input, (struct sockaddr *)&addr, addrlen, now + 5000);
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return true;
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}
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void send_response(int sock, struct json_object *result, bool compress,
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struct sockaddr_in *addr, socklen_t addrlen) {
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const char *output = NULL;
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size_t output_bytes;
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const char *str = json_object_to_json_string_ext(result, JSON_C_TO_STRING_PLAIN);
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if (compress) {
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size_t str_bytes = strlen(str);
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mz_ulong compressed_bytes = mz_compressBound(str_bytes);
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unsigned char *compressed = alloca(compressed_bytes);
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if (!mz_compress(compressed, &compressed_bytes, (const unsigned char *)str, str_bytes)) {
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output = (const char*)compressed;
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output_bytes = compressed_bytes;
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}
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}
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else {
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output = str;
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output_bytes = strlen(str);
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}
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if (output) {
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if (sendto(sock, output, output_bytes, 0, addr, addrlen) < 0)
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perror("sendto failed");
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}
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json_object_put(result);
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}
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void serve_request(struct request_schedule *schedule, int sock) {
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struct request_task* task = schedule_pop_request(schedule);
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if (task == NULL)
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return;
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bool compress;
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struct json_object *result = handle_request(task->request, &compress);
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if (!result)
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return;
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send_response(
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sock,
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result,
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compress,
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(struct sockaddr_in *) &task->client_addr,
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task->client_addrlen
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);
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free(task);
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}
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int main(int argc, char **argv) {
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const int one = 1;
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int sock;
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struct sockaddr_in6 server_addr = {};
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struct in6_addr mgroup_addr;
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sock = socket(PF_INET6, SOCK_DGRAM, 0);
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if (sock < 0) {
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perror("creating socket");
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exit(EXIT_FAILURE);
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}
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if (setsockopt(sock, IPPROTO_IPV6, IPV6_V6ONLY, &one, sizeof(one))) {
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perror("can't set socket to IPv6 only");
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exit(EXIT_FAILURE);
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}
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struct timeval timeout;
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timeout.tv_sec = 0;
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timeout.tv_usec = 10000;
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if (setsockopt (sock, SOL_SOCKET, SO_RCVTIMEO, (char *)&timeout,
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sizeof(timeout)) < 0)
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perror("setsockopt failed\n");
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server_addr.sin6_family = AF_INET6;
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server_addr.sin6_addr = in6addr_any;
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opterr = 0;
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int group_set = 0;
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int c;
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while ((c = getopt(argc, argv, "p:g:i:d:h")) != -1) {
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switch (c) {
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case 'p':
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server_addr.sin6_port = htons(atoi(optarg));
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break;
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case 'g':
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if (!inet_pton(AF_INET6, optarg, &mgroup_addr)) {
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perror("Invalid multicast group. This message will probably confuse you");
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exit(EXIT_FAILURE);
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}
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group_set = 1;
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break;
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case 'i':
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if (!group_set) {
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fprintf(stderr, "Multicast group must be given before interface.\n");
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exit(EXIT_FAILURE);
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}
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join_mcast(sock, mgroup_addr, optarg);
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break;
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case 'd':
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if (chdir(optarg)) {
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perror("Unable to change to given directory");
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exit(EXIT_FAILURE);
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}
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break;
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case 'h':
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usage();
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exit(EXIT_SUCCESS);
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break;
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default:
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fprintf(stderr, "Invalid parameter -%c ignored.\n", optopt);
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}
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}
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if (bind(sock, (struct sockaddr *)&server_addr, sizeof(server_addr)) < 0) {
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perror("bind failed");
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exit(EXIT_FAILURE);
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}
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load_providers();
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struct request_schedule schedule = {};
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while (true) {
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update_time();
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// TODO: adjust timeout, remove polling
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accept_request(&schedule, sock);
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serve_request(&schedule, sock);
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}
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return EXIT_FAILURE;
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}
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