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/*
* Copyright (c) 2009 - 2012 Marco Peereboom <marco@peereboom.us>
*
* Permission to use, copy, modify, and distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies.
*
* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*/
#include <stdio.h>
#include <stdlib.h>
#include <err.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <ldns/ldns.h>
#define INBUF_SIZE 4096
#define PORT 53
struct sockaddr paddr;
socklen_t plen = (socklen_t)sizeof(paddr);
int
udp_bind(int sock, uint16_t port)
{
struct sockaddr_in addr;
in_addr_t maddr = INADDR_ANY;
addr.sin_family = AF_INET;
addr.sin_port = (in_port_t) htons((uint16_t)port);
addr.sin_addr.s_addr = maddr;
return (bind(sock, (struct sockaddr*)&addr, (socklen_t) sizeof(addr)));
}
int
socket_create(uint16_t port) {
int so = socket(AF_INET, SOCK_DGRAM, 0);
if (so == -1)
err(1, "can't open socket");
if (udp_bind(so, port))
err(1, "can't udp bind");
return so;
}
void
printpacket(ldns_pkt *pkt)
{
char *str = ldns_pkt2str(pkt);
if (str) {
printf("%s", str);
LDNS_FREE(str);
} else
warnx("could not convert packet to string");
}
void receive_and_print(int so) {
uint8_t inbuf[INBUF_SIZE];
ssize_t nb;
ldns_status status;
ldns_pkt *query_pkt;
nb = recvfrom(so, inbuf, INBUF_SIZE, 0, &paddr, &plen);
if (nb == -1) {
if (errno == EINTR || errno == EAGAIN)
return;
else
err(EXIT_FAILURE, "recvfrom");
}
status = ldns_wire2pkt(&query_pkt, inbuf, (size_t)nb);
if (status != LDNS_STATUS_OK) {
warnx("bad packet: %s", ldns_get_errorstr_by_id(status));
return;
} else {
puts("received packet:");
printpacket(query_pkt);
}
ldns_pkt_free(query_pkt);
}
int main(int argc, char **argv) {
int so;
if (geteuid())
errx(1, "need root privileges");
so = socket_create(PORT);
while (1)
receive_and_print(so);
}
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