static int
thistcp (struct dns_transmit *d)
{
struct taia now;
const char *ip = NULL;
socketfree (d);
packetfree (d);
for (; d->curserver < 16; ++d->curserver)
{
ip = d->servers + 4 * d->curserver;
if (byte_diff (ip, 4, "\0\0\0\0"))
{
d->query[2] = dns_random (256);
d->query[3] = dns_random (256);
d->s1 = 1 + socket_tcp ();
if (!d->s1)
{
dns_transmit_free (d);
return -1;
}
if (randombind (d) == -1)
{
dns_transmit_free (d);
return -1;
}
taia_now (&now);
taia_uint (&d->deadline, 10);
taia_add (&d->deadline, &d->deadline, &now);
if (socket_connect4 (d->s1 - 1, ip, 53) == 0)
{
d->pos = 0;
d->tcpstate = 2;
return 0;
}
if (errno == error_inprogress || errno == error_wouldblock)
{
d->tcpstate = 1;
return 0;
}
socketfree(d);
}
}
dns_transmit_free(d);
return -1;
}
int dns_transmit_start(struct dns_transmit *d,const char servers[64],int flagrecursive,const char *q,const char qtype[2],const char localip[4])
{
unsigned int len;
dns_transmit_free(d);
errno = error_io;
len = dns_domain_length(q);
d->querylen = len + 18;
d->query = alloc(d->querylen);
if (!d->query) return -1;
uint16_pack_big(d->query,len + 16);
byte_copy(d->query + 2,12,flagrecursive ? "\0\0\1\0\0\1\0\0\0\0\0\0" : "\0\0\0\0\0\1\0\0\0\0\0\0gcc-bug-workaround");
byte_copy(d->query + 14,len,q);
byte_copy(d->query + 14 + len,2,qtype);
byte_copy(d->query + 16 + len,2,DNS_C_IN);
byte_copy(d->qtype,2,qtype);
d->servers = servers;
byte_copy(d->localip,4,localip);
d->udploop = flagrecursive ? 1 : 0;
if (len + 16 > 512) return firsttcp(d);
return firstudp(d);
}
int dns_mx(stralloc *out,const stralloc *fqdn)
{
if (!dns_domain_fromdot(&q,fqdn->s,fqdn->len)) return -1;
if (dns_resolve(q,DNS_T_MX) == -1) return -1;
if (dns_mx_packet(out,dns_resolve_tx.packet,dns_resolve_tx.packetlen) == -1) return -1;
dns_transmit_free(&dns_resolve_tx);
dns_domain_free(&q);
return 0;
}
/** Request the name (PTR) record for an IPv4 address. */
int dns_name4_r(struct dns_transmit* tx, struct dns_result* out, const ipv4addr *ip)
{
char name[DNS_NAME4_DOMAIN];
dns_name4_domain(name,ip);
if (dns_resolve(tx,name,DNS_T_PTR) == -1) return -1;
if (dns_name_packet(out,tx->packet,tx->packetlen) == -1) return -1;
dns_transmit_free(tx);
return 0;
}
static int doit(stralloc *out,stralloc *fqdn)
{
unsigned int i;
char code;
char ch;
char ip[16];
if (!stralloc_copys(out,"")) return -1;
if (!stralloc_readyplus(fqdn,1)) return -1;
fqdn->s[fqdn->len]=0;
if ((i=ip6_scan(fqdn->s,ip))) {
if (!fqdn->s[i]) {
stralloc_copyb(out,ip,16);
return 0;
}
}
if ((i=ip4_scan(fqdn->s,ip+12))) {
if (!fqdn->s[i]) {
byte_zero(ip,10);
ip[10]=ip[11]=0xff;
stralloc_copyb(out,ip,16);
return 0;
}
}
code = 0;
for (i = 0;i <= fqdn->len;++i) {
if (i < fqdn->len)
ch = fqdn->s[i];
else
ch = '.';
if ((ch == '[') || (ch == ']')) continue;
if (ch == '.') {
if (!stralloc_append(out,&code)) return -1;
code = 0;
continue;
}
if ((ch >= '0') && (ch <= '9')) {
code *= 10;
code += ch - '0';
continue;
}
if (!dns_domain_fromdot(&q,fqdn->s,fqdn->len)) return -1;
if (dns_resolve(q,DNS_T_AAAA) == -1) return -1;
if (dns_ip6_packet(out,dns_resolve_tx.packet,dns_resolve_tx.packetlen) == -1) return -1;
dns_transmit_free(&dns_resolve_tx);
dns_domain_free(&q);
return 0;
}
out->len &= ~3;
return 0;
}
static int thisudp(struct dns_transmit *d)
{
const char *ip;
socketfree(d);
while (d->udploop < 4) {
for (;d->curserver < 16;++d->curserver) {
ip = d->servers + 4 * d->curserver;
if (byte_diff(ip,4,"\0\0\0\0")) {
d->query[2] = dns_random(256);
d->query[3] = dns_random(256);
d->s1 = 1 + socket_udp();
if (!d->s1) { dns_transmit_free(d); return -1; }
if (randombind(d) == -1) { dns_transmit_free(d); return -1; }
if (socket_connect4(d->s1 - 1,ip,53) == 0)
if (send(d->s1 - 1,d->query + 2,d->querylen - 2,0) == d->querylen - 2) {
struct taia now;
taia_now(&now);
taia_uint(&d->deadline,timeouts[d->udploop]);
taia_add(&d->deadline,&d->deadline,&now);
d->tcpstate = 0;
return 0;
}
socketfree(d);
}
}
++d->udploop;
d->curserver = 0;
}
dns_transmit_free(d); return -1;
}
static int thistcp(struct dns_transmit *d)
{
struct taia now;
const char *ip;
socketfree(d);
packetfree(d);
for (;d->curserver < 16;++d->curserver) {
ip = d->servers + 16 * d->curserver;
if (byte_diff(ip,16,V6any)) {
d->query[2] = dns_random(256);
d->query[3] = dns_random(256);
d->s1 = 1 + socket_tcp6();
if (!d->s1) { dns_transmit_free(d); return -1; }
if (randombind(d) == -1) { dns_transmit_free(d); return -1; }
taia_now(&now);
taia_uint(&d->deadline,10);
taia_add(&d->deadline,&d->deadline,&now);
if (socket_connect6(d->s1 - 1,ip,53,d->scope_id) == 0) {
d->tcpstate = 2;
return 0;
}
if ((errno == error_inprogress) || (errno == error_wouldblock)) {
d->tcpstate = 1;
return 0;
}
socketfree(d);
}
}
dns_transmit_free(d); return -1;
}
/** Request the IPv4 address (A) records for a domain name. */
int dns_ip4_r(struct dns_transmit* tx, struct dns_result *out, const char* fqdn)
{
char *q = 0;
ipv4addr ip;
const char* x;
if ((x = ipv4_scan(fqdn, &ip)) != 0 && *x == 0) {
if (dns_result_alloc(out, DNS_T_A, 1, 0) < 0)
return -1;
memcpy(out->rr.ip4, &ip, sizeof ip);
return 0;
}
if (!dns_domain_fromdot(&q,fqdn,strlen(fqdn))) return -1;
if (dns_resolve(tx,q,DNS_T_A) == -1) { free(q); return -1; }
free(q);
if (dns_ip4_packet(out,tx->packet,tx->packetlen) == -1) return -1;
dns_transmit_free(tx);
return 0;
}
int dns_ip4(stralloc *out,const stralloc *fqdn)
{
unsigned int i;
char code;
char ch;
if (!stralloc_copys(out,"")) return -1;
code = 0;
for (i = 0;i <= fqdn->len;++i) {
if (i < fqdn->len)
ch = fqdn->s[i];
else
ch = '.';
if ((ch == '[') || (ch == ']')) continue;
if (ch == '.') {
if (!stralloc_append(out,&code)) return -1;
code = 0;
continue;
}
if ((ch >= '0') && (ch <= '9')) {
code *= 10;
code += ch - '0';
continue;
}
if (!dns_domain_fromdot(&q,fqdn->s,fqdn->len)) return -1;
if (dns_resolve(q,DNS_T_A) == -1) return -1;
if (dns_ip4_packet(out,dns_resolve_tx.packet,dns_resolve_tx.packetlen) == -1) return -1;
dns_transmit_free(&dns_resolve_tx);
dns_domain_free(&q);
return 0;
}
out->len &= ~3;
return 0;
}
int dns_transmit_get(struct dns_transmit *d,const iopause_fd *x,const struct taia *when)
{
char udpbuf[513];
unsigned char ch;
int r;
int fd;
errno = error_io;
fd = d->s1 - 1;
if (!x->revents) {
if (taia_less(when,&d->deadline)) return 0;
errno = error_timeout;
if (d->tcpstate == 0) return nextudp(d);
return nexttcp(d);
}
if (d->tcpstate == 0) {
/*
have attempted to send UDP query to each server udploop times
have sent query to curserver on UDP socket s
*/
r = recv(fd,udpbuf,sizeof udpbuf,0);
if (r <= 0) {
if (errno == error_connrefused) if (d->udploop == 2) return 0;
return nextudp(d);
}
if (r + 1 > sizeof udpbuf) return 0;
if (irrelevant(d,udpbuf,r)) return 0;
if (serverwantstcp(udpbuf,r)) return firsttcp(d);
if (serverfailed(udpbuf,r)) {
if (d->udploop == 2) return 0;
return nextudp(d);
}
socketfree(d);
d->packetlen = r;
d->packet = alloc(d->packetlen);
if (!d->packet) { dns_transmit_free(d); return -1; }
byte_copy(d->packet,d->packetlen,udpbuf);
queryfree(d);
return 1;
}
if (d->tcpstate == 1) {
/*
have sent connection attempt to curserver on TCP socket s
pos not defined
*/
if (!socket_connected(fd)) return nexttcp(d);
d->pos = 0;
d->tcpstate = 2;
return 0;
}
if (d->tcpstate == 2) {
/*
have connection to curserver on TCP socket s
have sent pos bytes of query
*/
r = write(fd,d->query + d->pos,d->querylen - d->pos);
if (r <= 0) return nexttcp(d);
d->pos += r;
if (d->pos == d->querylen) {
struct taia now;
taia_now(&now);
taia_uint(&d->deadline,10);
taia_add(&d->deadline,&d->deadline,&now);
d->tcpstate = 3;
}
return 0;
}
if (d->tcpstate == 3) {
/*
have sent entire query to curserver on TCP socket s
pos not defined
*/
r = read(fd,&ch,1);
if (r <= 0) return nexttcp(d);
d->packetlen = ch;
d->tcpstate = 4;
return 0;
}
if (d->tcpstate == 4) {
/*
have sent entire query to curserver on TCP socket s
pos not defined
have received one byte of packet length into packetlen
*/
r = read(fd,&ch,1);
if (r <= 0) return nexttcp(d);
d->packetlen <<= 8;
d->packetlen += ch;
d->tcpstate = 5;
d->pos = 0;
d->packet = alloc(d->packetlen);
if (!d->packet) { dns_transmit_free(d); return -1; }
return 0;
}
if (d->tcpstate == 5) {
/*
have sent entire query to curserver on TCP socket s
have received entire packet length into packetlen
packet is allocated
have received pos bytes of packet
*/
r = read(fd,d->packet + d->pos,d->packetlen - d->pos);
if (r <= 0) return nexttcp(d);
d->pos += r;
if (d->pos < d->packetlen) return 0;
socketfree(d);
if (irrelevant(d,d->packet,d->packetlen)) return nexttcp(d);
if (serverwantstcp(d->packet,d->packetlen)) return nexttcp(d);
if (serverfailed(d->packet,d->packetlen)) return nexttcp(d);
queryfree(d);
return 1;
}
return 0;
}
static int
thisudp (struct dns_transmit *d)
{
const char *ip = NULL;
socketfree (d);
mergefree (d);
while (d->udploop < 4)
{
for (; d->curserver < 16; ++d->curserver)
{
ip = d->servers + 4 * d->curserver;
if (byte_diff (ip, 4, "\0\0\0\0"))
{
if (merge_enable && try_merge (d))
{
if (merge_logger)
merge_logger (ip, d->qtype, d->query + 14);
return 0;
}
d->query[2] = dns_random (256);
d->query[3] = dns_random (256);
d->s1 = 1 + socket_udp ();
if (!d->s1)
{
dns_transmit_free (d);
return -1;
}
if (randombind (d) == -1)
{
dns_transmit_free (d);
return -1;
}
if (socket_connect4 (d->s1 - 1, ip, 53) == 0)
{
if (send (d->s1 - 1, d->query + 2, d->querylen - 2, 0)
== d->querylen - 2)
{
struct taia now;
taia_now (&now);
taia_uint (&d->deadline, timeouts[d->udploop]);
taia_add (&d->deadline, &d->deadline, &now);
d->tcpstate = 0;
if (merge_enable)
register_inprogress (d);
return 0;
}
}
socketfree (d);
}
}
++d->udploop;
d->curserver = 0;
}
dns_transmit_free (d);
return -1;
}
