From 249866e3d1e11dc72eaa1305f4bb479ded92ef38 Mon Sep 17 00:00:00 2001 From: Jannis Hoffmann Date: Tue, 9 Jul 2024 13:58:20 +0200 Subject: reorganized file structure Moved c files into src/. Corrected VERSION file. Removed BUILD and FILES. --- dnsstub/dns_transmit.c | 436 ------------------------------------------------- 1 file changed, 436 deletions(-) delete mode 100644 dnsstub/dns_transmit.c (limited to 'dnsstub/dns_transmit.c') 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 -#include -#include -#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; -} -- cgit v1.2.3