mirror of
https://github.com/yarrick/iodine.git
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151 lines
2.9 KiB
C
151 lines
2.9 KiB
C
/*
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* Copyright (c) 2006 Bjorn Andersson <flex@kryo.se>, Erik Ekman <yarrick@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 <netdb.h>
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#include <time.h>
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#include <err.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 "dns.h"
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static int host2dns(const char *, char *, int);
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struct sockaddr_in peer;
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int
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open_dns()
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{
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int fd;
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int flag;
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struct sockaddr_in addr;
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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(0);
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addr.sin_addr.s_addr = htonl(INADDR_ANY);
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fd = socket(AF_INET, SOCK_DGRAM, 0);
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if(fd < 0) {
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warn("Could not get UDP socket");
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return 0;
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}
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flag = 1;
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#ifdef SO_REUSEPORT
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setsockopt(fd, SOL_SOCKET, SO_REUSEPORT, &flag, sizeof(flag));
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#endif
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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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warn("Could not bind UDP socket locally");
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return 0;
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}
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printf("Opened UDP socket\n");
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return fd;
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}
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void
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close_dns(int fd)
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{
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close(fd);
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}
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void
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dns_set_peer(const char *host)
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{
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struct hostent *h;
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h = gethostbyname(host);
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bzero(&peer, sizeof(peer));
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peer.sin_family = AF_INET;
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peer.sin_port = htons(53);
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peer.sin_addr = *((struct in_addr *) h->h_addr);
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}
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void
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dns_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 peerlen;
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char buf[1024];
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HEADER *header;
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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 = 1;
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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(C_IN, p);
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peerlen = sizeof(peer);
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len = p - buf;
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sendto(fd, buf, len+1, 0, (struct sockaddr*)&peer, peerlen);
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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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