temporary data
This commit is contained in:
Bjorn Andersson
parent
ba2abc6e69
commit
c25e1500a4
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/*
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* Copyright (c) 2006 Bjorn Andersson <flex@kryo.se>
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*
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* Permission to use, copy, modify, and distribute this software for any
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* purpose with or without fee is hereby granted, provided that the above
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* copyright notice and this permission notice appear in all copies.
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*
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* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
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* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
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* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
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* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
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* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
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* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
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* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
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*/
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#include <sys/types.h>
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#include <sys/socket.h>
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#include <netinet/in.h>
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#include <arpa/inet.h>
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#include <arpa/nameser.h>
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#include <time.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <unistd.h>
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#include <string.h>
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#include <ctype.h>
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#include "mdns.h"
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#define MAX_PACKET_LEN 1024
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struct servicetree services = RB_INITIALIZER(&services);
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int
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servicecmp(struct mdns_service *a, struct mdns_service *b)
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{
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return strcmp(a->net, b->net);
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}
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RB_GENERATE(servicetree, mdns_service, entry, servicecmp);
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extern void peer_event(int, struct mdns_peer*);
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void
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mdns_register_service(struct mdns_service *service)
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{
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RB_INSERT(servicetree, &services, service);
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}
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void
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mdns_unregister_service(struct mdns_service *service)
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{
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if(service) {
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RB_REMOVE(servicetree, &services, service);
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}
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}
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static int
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readname(char *packet, char *dst, char *src)
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{
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char l;
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int len;
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int offset;
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len = 0;
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while(*src) {
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l = *src++;
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len++;
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if(l & 0x80 && l & 0x40) {
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offset = ((src[-1] & 0x3f) << 8) | src[0];
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readname(packet, dst, packet + offset);
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dst += strlen(dst);
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break;
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}
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while(l) {
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*dst++ = *src++;
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l--;
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len++;
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}
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*dst++ = '.';
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}
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*dst = '\0';
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src++;
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len++;
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return len;
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}
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#define READNAME(packet, dst, src) (src) += readname((packet), (dst), (src));
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#define READSHORT(dst, src) \
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(dst) = ntohs(*(short*)(src)); (src)+=2;
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#define READLONG(dst, src) \
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(dst) = ntohl(*(long*)(src)); (src)+=4;
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#define READDATA(dst, src, len) \
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memcpy((dst), (src), (len)); (src)+=(len);
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int
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mdns_open()
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{
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int fd;
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int ttl;
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int flag;
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struct sockaddr_in addr;
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struct ip_mreq mc;
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bzero(&addr, sizeof(addr));
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addr.sin_family = AF_INET;
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addr.sin_port = htons(5353);
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addr.sin_addr.s_addr = 0;
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fd = socket(AF_INET, SOCK_DGRAM, 0);
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if(fd < 0) {
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perror("socket");
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exit(1);
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}
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flag = 1;
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setsockopt(fd, SOL_SOCKET, SO_REUSEPORT, &flag, sizeof(flag));
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setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, &flag, sizeof(flag));
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if(bind(fd, (struct sockaddr*)&addr, sizeof(addr)) < 0) {
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perror("bind");
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exit(1);
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}
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mc.imr_multiaddr.s_addr = inet_addr("224.0.0.251");
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mc.imr_interface.s_addr = inet_addr("192.168.7.208"); //htonl(INADDR_ANY);
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if(setsockopt(fd, IPPROTO_IP, IP_ADD_MEMBERSHIP, &mc, sizeof(mc)) < 0) {
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perror("ip_add_membership");
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exit(1);
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}
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ttl = 255;
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setsockopt(fd, IPPROTO_IP, IP_MULTICAST_TTL, &ttl, sizeof(ttl));
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return fd;
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}
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static int
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host2dns(const char *host, char *buffer, int size)
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{
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char *h;
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char *p;
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char *word;
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h = strdup(host);
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memset(buffer, 0, size);
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p = buffer;
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word = strtok(h, ".");
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while(word) {
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*p++ = (char)strlen(word);
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memcpy(p, word, strlen(word));
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p += strlen(word);
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word = strtok(NULL, ".");
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}
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*p++ = 0;
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free(h);
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return p - buffer;
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}
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static void
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mdns_respond(int fd, struct mdns_service *service)
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{
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int len;
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int size;
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HEADER *header;
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char *p;
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int addrlen;
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char buf[1024];
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char host[256];
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struct sockaddr_in addr;
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snprintf(host, sizeof(host), "%s.%s", service->name, service->net);
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memset(buf, 0, sizeof(buf));
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len = 0;
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header = (HEADER*)buf;
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header->id = 0;
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header->qr = 1;
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header->opcode = 0;
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header->aa = 1;
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header->tc = 0;
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header->rd = 0;
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header->ra = 0;
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header->ancount = htons(2);
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p = buf + sizeof(HEADER);
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p += host2dns(service->net, p, strlen(service->net));
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PUTSHORT(T_PTR, p);
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PUTSHORT(C_IN, p);
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PUTLONG(htons(3600), p);
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size = host2dns(host, p+2, strlen(host));
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PUTSHORT(size, p);
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p += size;
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p += host2dns(host, p, strlen(host));
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PUTSHORT(T_SRV, p);
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PUTSHORT(0x8001, p);
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PUTLONG(service->ttl, p);
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size = host2dns(service->host, p+8, strlen(service->host));
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size += 6;
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PUTSHORT(size, p);
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PUTSHORT(0, p);
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PUTSHORT(0, p);
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PUTSHORT(service->port, p);
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p+= size;
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bzero(&addr, sizeof(addr));
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addr.sin_family = AF_INET;
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addr.sin_addr.s_addr = inet_addr("224.0.0.251");
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addr.sin_port = htons(5353);
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addrlen = sizeof(addr);
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len = p - buf;
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sendto(fd, buf, len + 1, 0, (struct sockaddr*)&addr, addrlen);
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}
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void
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mdns_handle(int fd)
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{
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int i;
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int ssize;
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long ttl;
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short rlen;
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short type;
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short class;
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short ancount;
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short qdcount;
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char *data;
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char name[255];
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char rdata[256];
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HEADER *header;
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struct mdns_peer *peer;
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struct sockaddr_in from;
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char buf[MAX_PACKET_LEN];
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i = recvfrom(fd, buf, MAX_PACKET_LEN, 0, (struct sockaddr*)&from, &ssize);
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if(i == -1) {
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perror("recvfrom");
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} else {
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header = (HEADER*)buf;
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data = buf + sizeof(HEADER);
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if(header->qr) { /* qr=1 => response */
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peer = malloc(sizeof(struct mdns_peer));
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ancount = ntohs(header->ancount);
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for(i=0;i<ancount;i++) {
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READNAME(buf, name, data);
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READSHORT(type, data);
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READSHORT(class, data);
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READLONG(ttl, data);
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READSHORT(rlen, data);
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READDATA(rdata, data, rlen);
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if(type == T_SRV && rlen > 6) {
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char *r;
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short priority;
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short weight;
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r = rdata;
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peer->name = strdup(name);
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peer->host = malloc(rlen);
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peer->ttl = ttl;
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READSHORT(priority, r);
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READSHORT(weight, r);
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READSHORT(peer->port, r);
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READNAME(buf, peer->host, r);
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peer->host[strlen(peer->host)-1] = '\0';
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peer_event(1, peer);
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}
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}
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} else { /* qr=0 => query */
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qdcount = ntohs(header->qdcount);
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for(i=0;i<qdcount;i++) {
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READNAME(buf, name, data);
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READSHORT(type, data);
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READSHORT(class, data);
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if(type == T_PTR) {
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struct mdns_service needle;
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struct mdns_service *service;
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needle.net = name;
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service = RB_FIND(servicetree, &services, &needle);
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if(service && strcmp(service->net, name) == 0) {
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mdns_respond(fd, service);
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}
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}
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}
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}
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}
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}
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void
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mdns_query(int fd, char *host, int type)
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{
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char *p;
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int len;
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int addrlen;
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char buf[1024];
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HEADER *header;
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struct sockaddr_in addr;
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len = 0;
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memset(buf, 0, sizeof(buf));
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header = (HEADER*)buf;
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header->id = 0;
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header->qr = 0;
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header->opcode = 0;
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header->aa = 0;
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header->tc = 0;
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header->rd = 0;
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header->ra = 0;
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header->qdcount = htons(1);
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p = buf + sizeof(HEADER);
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p += host2dns(host, p, strlen(host));
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PUTSHORT(type, p);
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PUTSHORT(01, p);
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bzero(&addr, sizeof(addr));
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addr.sin_family = AF_INET;
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addr.sin_addr.s_addr = inet_addr("224.0.0.251");
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addr.sin_port = htons(5353);
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addrlen = sizeof(addr);
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len = p - buf;
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sendto(fd, buf, len+1, 0, (struct sockaddr*)&addr, addrlen);
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}
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@ -0,0 +1,50 @@
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/*
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* Copyright (c) 2006 Bjorn Andersson <flex@kryo.se>
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*
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* Permission to use, copy, modify, and distribute this software for any
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* purpose with or without fee is hereby granted, provided that the above
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* copyright notice and this permission notice appear in all copies.
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||||
*
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||||
* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
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* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
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* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
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* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
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* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
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* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
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* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
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*/
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#ifndef __MDNS_H__
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#define __MDNS_H__
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#include <sys/tree.h>
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struct mdns_peer {
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RB_ENTRY(mdns_peer) entry;
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char *name;
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char *host;
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short port;
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short ttl;
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};
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struct mdns_service {
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RB_ENTRY(mdns_service) entry;
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char *name;
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char *net;
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char *host;
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short port;
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short ttl;
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};
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RB_HEAD(servicetree, mdns_service);
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int mdns_open();
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void mdns_query(int, char*, int);
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void mdns_handle(int);
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void mdns_register_service(struct mdns_service *);
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void mdns_unregister_service(struct mdns_service *);
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#endif
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