sortix-mirror/dnsconfig/dnsconfig.c

131 lines
3.4 KiB
C

/*
* Copyright (c) 2021 Juhani 'nortti' Krekelä.
*
* 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.
*
* dnsconfig.c
* Configure kernel DNS resolver list.
*/
#include <sys/dnsconfig.h>
#include <sys/socket.h>
#include <arpa/inet.h>
#include <err.h>
#include <getopt.h>
#include <stdbool.h>
#include <stdio.h>
#include <string.h>
int main(int argc, char* argv[])
{
bool append = false;
bool delete = false;
bool set = false;
int opt;
while ( (opt = getopt(argc, argv, "ads")) != -1 )
{
switch ( opt )
{
case 'a': append = true; break;
case 'd': delete = true; break;
case 's': set = true; break;
}
}
if ( append + delete + set > 1 )
errx(1, "-a, -d, -s are mutually exclusive");
// If no mode is provided but there are arguments, default to set.
if ( !append && !delete && !set && optind < argc )
set = true;
struct dnsconfig dnsconfig = {0};
if ( !set && getdnsconfig(&dnsconfig) < 0 )
err(1, "getdnsconfig");
if ( append || delete || set )
{
for ( int i = optind; i < argc; i++ )
{
struct dnsconfig_server server = {0};
if ( inet_pton(AF_INET, argv[i], &server.addr.in) )
{
server.family = AF_INET;
server.addrsize = sizeof(server.addr.in);
}
else if ( inet_pton(AF_INET6, argv[i], &server.addr.in6) )
{
server.family = AF_INET6;
server.addrsize = sizeof(server.addr.in6);
}
else
errx(1, "Invalid address: %s", argv[i]);
if ( !delete )
{
size_t index = dnsconfig.servers_count++;
if ( dnsconfig.servers_count > DNSCONFIG_MAX_SERVERS )
errx(1, "Too many DNS resolvers (%zu max)",
(size_t) DNSCONFIG_MAX_SERVERS);
dnsconfig.servers[index] = server;
}
else
{
// Search for a matching entry.
bool found = false;
for ( size_t j = 0; j < dnsconfig.servers_count; j++ )
{
if ( dnsconfig.servers[j].family != server.family ||
memcmp(&dnsconfig.servers[j].addr, &server.addr,
server.addrsize) )
continue;
for ( size_t k = j + 1; k < dnsconfig.servers_count; k++ )
dnsconfig.servers[k - 1] = dnsconfig.servers[k];
dnsconfig.servers_count--;
memset(&dnsconfig.servers[dnsconfig.servers_count], 0,
sizeof(struct dnsconfig_server));
found = true;
break;
}
if ( !found )
errx(1, "Resolver not in the list: %s", argv[i]);
}
}
if ( setdnsconfig(&dnsconfig) < 0 )
err(1, "setdnsconfig");
}
else
{
for ( size_t i = 0; i < dnsconfig.servers_count; i++ )
{
char address[INET6_ADDRSTRLEN];
if ( !inet_ntop(dnsconfig.servers[i].family,
&dnsconfig.servers[i].addr,
address, sizeof(address)) )
err(1, "inet_ntop");
if ( printf("%s\n", address) < 0 )
err(1, "stdout");
}
if ( fflush(stdout) )
err(1, "stdout");
}
return 0;
}