summaryrefslogtreecommitdiff
path: root/dnsstub/dns_transmit.c
diff options
context:
space:
mode:
Diffstat (limited to 'dnsstub/dns_transmit.c')
-rw-r--r--dnsstub/dns_transmit.c436
1 files changed, 0 insertions, 436 deletions
diff --git a/dnsstub/dns_transmit.c b/dnsstub/dns_transmit.c
deleted file mode 100644
index 2513565..0000000
--- a/dnsstub/dns_transmit.c
+++ /dev/null
@@ -1,436 +0,0 @@
-#include <sys/types.h>
-#include <sys/socket.h>
-#include <unistd.h>
-#include "socket_if.h"
-#include "alloc.h"
-#include "error.h"
-#include "byte.h"
-#include "uint_t.h"
-#include "ip.h"
-#include "dnsresolv.h"
-
-/**
- @file dns_transmit.c
- @authors djb, fefe, feh
- @source qlibs
- @brief DNS query function
- @brief scope_ids[32] -> 32 LLU root servers supported
-*/
-
-#define DNSPORT 53
-
-uint32 scope_ids[QUERY_MAXNS];
-
-static const int timeouts[5] = { 1, 2, 4, 8, 16 }; /* quadratic, not exponentially */
-
-int getscopeid(const struct dns_transmit *d,const char *ip)
-{
- int i;
-
- if (byte_diff(ip,2,V6linklocal)) return 0;
- for (i = 0; i < QUERY_MAXNS; ++i)
- if (byte_equal(d->servers + 16 * i,16,ip))
- return scope_ids[i];
-
- return 0;
-}
-
-int serverwantstcp(const char *buf,unsigned int len)
-{
- char out[12];
-
- if (!dns_packet_copy(buf,len,0,out,12)) return 1;
- if (out[2] & 2) return 1;
-
- return 0;
-}
-
-int serverfailed(const char *buf,unsigned int len)
-{
- char out[12];
- unsigned int rcode;
-
- if (!dns_packet_copy(buf,len,0,out,12)) return 1;
- rcode = out[3];
- rcode &= 15;
- if (rcode && (rcode != 3)) { errno = EAGAIN; return 1; }
-
- return 0;
-}
-
-int irrelevant(const struct dns_transmit *d,const char *buf,unsigned int len)
-{
- char out[12];
- char *dn;
- unsigned int pos;
-
- pos = dns_packet_copy(buf,len,0,out,12); if (!pos) return 1;
- if (byte_diff(out,2,d->query + 2)) return 1;
- if (out[4] != 0) return 1;
- if (out[5] != 1) return 1;
-
- dn = 0;
- pos = dns_packet_getname(buf,len,pos,&dn); if (!pos) return 1;
- if (!dns_domain_equal(dn,d->query + 14)) { alloc_free(dn); return 1; }
- alloc_free(dn);
-
- pos = dns_packet_copy(buf,len,pos,out,4); if (!pos) return 1;
- if (byte_diff(out,2,d->qtype)) return 1;
- if (byte_diff(out + 2,2,DNS_C_IN)) return 1;
-
- return 0;
-}
-
-void packetfree(struct dns_transmit *d)
-{
- if (!d->packet) return;
- alloc_free(d->packet);
- d->packet = 0;
-}
-
-void queryfree(struct dns_transmit *d)
-{
- if (!d->query) return;
- alloc_free(d->query);
- d->query = 0;
-}
-
-void socketfree(struct dns_transmit *d)
-{
- if (!d->s1) return;
- close(d->s1 - 1);
- d->s1 = 0;
-}
-
-void dns_transmit_free(struct dns_transmit *d)
-{
- queryfree(d);
- socketfree(d);
- packetfree(d);
-}
-
-int randombind6(struct dns_transmit *d)
-{
- int j;
-
- for (j = 0; j < 10; ++j) {
- if (socket_bind6(d->s1 - 1,d->localip,1025 + dns_random(64510),d->scope_id) == 0)
- return 0;
- }
- if (socket_bind6(d->s1 - 1,d->localip,0,d->scope_id) == 0)
- return 0;
-
- return DNS_COM;
-}
-
-int randombind4(struct dns_transmit *d)
-{
- int j;
-
- for (j = 0; j < 10; ++j) {
- if (socket_bind4(d->s1 - 1,d->localip + 12,1025 + dns_random(64510)) == 0)
- return 0;
- }
- if (socket_bind4(d->s1 - 1,d->localip + 12,0) == 0)
- return 0;
-
- return DNS_COM;
-}
-
-int thisudp(struct dns_transmit *d)
-{
- const char *ip;
-
- socketfree(d);
-
- while (d->udploop < 5) {
- for (; d->curserver < QUERY_MAXNS; ++d->curserver) {
- ip = d->servers + 16 * d->curserver;
- if (byte_diff(ip,16,V6localnet)) {
- d->query[2] = dns_random(256);
- d->query[3] = dns_random(256);
-
- if (ip6_isv4mapped(ip)) {
- d->s1 = 1 + socket_udp4();
- if (!d->s1) { dns_transmit_free(d); return DNS_COM; }
- if (randombind4(d) < 0) { dns_transmit_free(d); return DNS_COM; }
- } else {
- d->s1 = 1 + socket_udp6();
- if (!d->s1) { dns_transmit_free(d); return DNS_COM; }
- if (randombind6(d) < 0) { dns_transmit_free(d); return DNS_COM; }
- }
-
- if (byte_equal(ip,2,V6linklocal) && !d->scope_id)
- d->scope_id = getscopeid(d,ip);
- if (socket_connect(d->s1 - 1,ip,DNSPORT,d->scope_id) == 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 DNS_COM;
-}
-
-int firstudp(struct dns_transmit *d)
-{
- d->curserver = 0;
- return thisudp(d);
-}
-
-int nextudp(struct dns_transmit *d)
-{
- ++d->curserver;
- return thisudp(d);
-}
-
-int thistcp(struct dns_transmit *d)
-{
- struct taia now;
- const char *ip;
-
- socketfree(d);
- packetfree(d);
-
- for (; d->curserver < QUERY_MAXNS; ++d->curserver) {
- ip = d->servers + 16 * d->curserver;
- if (byte_diff(ip,16,V6localnet)) {
- d->query[2] = dns_random(256);
- d->query[3] = dns_random(256);
-
- if (ip6_isv4mapped(ip)) {
- d->s1 = 1 + socket_tcp4();
- if (!d->s1) { dns_transmit_free(d); return DNS_COM; }
- if (randombind4(d) < 0) { dns_transmit_free(d); return DNS_COM; }
- } else {
- d->s1 = 1 + socket_tcp6();
- if (!d->s1) { dns_transmit_free(d); return DNS_COM; }
- if (randombind6(d) < 0) { dns_transmit_free(d); return DNS_COM; }
- }
-
- taia_now(&now);
- taia_uint(&d->deadline,10);
- taia_add(&d->deadline,&d->deadline,&now);
-
- if (byte_equal(ip,2,V6linklocal) && !d->scope_id)
- d->scope_id = getscopeid(d,ip);
- if (socket_connect(d->s1 - 1,ip,DNSPORT,d->scope_id) == 0) {
- d->tcpstate = 2;
- return 0;
- }
- if ((errno == EINPROGRESS) || (errno == EWOULDBLOCK)) {
- d->tcpstate = 1;
- return 0;
- }
-
- socketfree(d);
- }
- }
-
- dns_transmit_free(d);
- return DNS_COM;
-}
-
-int firsttcp(struct dns_transmit *d)
-{
- d->curserver = 0;
- return thistcp(d);
-}
-
-int nexttcp(struct dns_transmit *d)
-{
- ++d->curserver;
- return thistcp(d);
-}
-
-int dns_transmit_start(struct dns_transmit *d,const char servers[QUERY_MAXIPLEN], \
- int flagrecursive,const char *q,const char qtype[2],const char localip[16])
-{
- unsigned int len;
-
- dns_transmit_free(d);
- errno = EIO;
-
- len = dns_domain_length(q);
- d->querylen = len + 18;
- d->query = alloc(d->querylen);
- if (!d->query) return DNS_COM;
-
- 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,(char *) qtype);
- d->servers = servers;
- byte_copy(d->localip,16,(char *) localip);
-
- d->udploop = flagrecursive ? 1 : 0;
-
- if (len + 16 > MSGSIZE) return firsttcp(d);
- return firstudp(d);
-}
-
-int dns_transmit_start6(struct dns_transmit *d,const char servers[QUERY_MAXIPLEN], \
- int flagrecursive,const char *q,const char qtype[2], \
- const char localip[16],const uint32 scopes[QUERY_MAXNS])
-{
- byte_copy(scope_ids,128,(char *) scopes);
-
- return dns_transmit_start(d,servers,flagrecursive,q,qtype,localip);
-}
-
-void dns_transmit_io(struct dns_transmit *d,iopause_fd *x,struct taia *deadline)
-{
- x->fd = d->s1 - 1;
-
- switch (d->tcpstate) {
- case 0: case 3: case 4: case 5:
- x->events = IOPAUSE_READ;
- break;
- case 1: case 2:
- x->events = IOPAUSE_WRITE;
- break;
- }
-
- if (taia_less(&d->deadline,deadline))
- *deadline = d->deadline;
-}
-
-int dns_transmit_get(struct dns_transmit *d,const iopause_fd *x,const struct taia *when)
-{
- char udpbuf[MSGSIZE + 1];
- unsigned char ch;
- int r;
- int fd;
-
- errno = EIO;
- fd = d->s1 - 1;
-
- if (!x->revents) {
- if (taia_less((struct taia *)when,&d->deadline)) return 0;
- errno = ETIMEDOUT;
- if (d->tcpstate == 0) return nextudp(d);
- return nexttcp(d);
- }
-
-/*
-have attempted to send UDP query to each server udploop times
-have sent query to curserver on UDP socket s
-*/
- if (d->tcpstate == 0) {
- r = recv(fd,udpbuf,sizeof(udpbuf),0);
- if (r <= 0) {
- if (errno == ECONNREFUSED) 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 DNS_COM; }
- byte_copy(d->packet,d->packetlen,udpbuf);
- queryfree(d);
- return 1;
- }
-
-/*
-have sent connection attempt to curserver on TCP socket s
-pos not defined
-*/
- if (d->tcpstate == 1) {
- if (!socket_connected(fd)) return nexttcp(d);
- d->pos = 0;
- d->tcpstate = 2;
- return 0;
- }
-
-/*
-have connection to curserver on TCP socket s
-have sent pos bytes of query
-*/
- if (d->tcpstate == 2) {
- 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;
- }
-
-/*
-have sent entire query to curserver on TCP socket s
-pos not defined
-*/
- if (d->tcpstate == 3) {
- r = read(fd,&ch,1);
- if (r <= 0) return nexttcp(d);
- d->packetlen = ch;
- d->tcpstate = 4;
- return 0;
- }
-
-/*
-have sent entire query to curserver on TCP socket s
-pos not defined
-have received one byte of packet length into packetlen
-*/
- if (d->tcpstate == 4) {
- 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 DNS_COM; }
- return 0;
- }
-
-/*
-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
-*/
- if (d->tcpstate == 5) {
- 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;
-}
generated by cgit v1.2.3 (git 2.39.1) at 2024-12-23 12:19:01 +0000