| 1 | /* |
| 2 | * transmit.c |
| 3 | * - construct queries |
| 4 | * - send queries |
| 5 | */ |
| 6 | /* |
| 7 | * This file is part of adns, which is Copyright (C) 1997, 1998 Ian Jackson |
| 8 | * |
| 9 | * This program is free software; you can redistribute it and/or modify |
| 10 | * it under the terms of the GNU General Public License as published by |
| 11 | * the Free Software Foundation; either version 2, or (at your option) |
| 12 | * any later version. |
| 13 | * |
| 14 | * This program is distributed in the hope that it will be useful, |
| 15 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 16 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 17 | * GNU General Public License for more details. |
| 18 | * |
| 19 | * You should have received a copy of the GNU General Public License |
| 20 | * along with this program; if not, write to the Free Software Foundation, |
| 21 | * Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. |
| 22 | */ |
| 23 | |
| 24 | #include <errno.h> |
| 25 | #include <string.h> |
| 26 | |
| 27 | #include <sys/uio.h> |
| 28 | |
| 29 | #include "internal.h" |
| 30 | |
| 31 | adns_status adns__mkquery(adns_state ads, vbuf *vb, int *id_r, |
| 32 | const char *owner, int ol, |
| 33 | const typeinfo *typei, adns_queryflags flags) { |
| 34 | int ll, c, nlabs, id; |
| 35 | byte label[255], *rqp; |
| 36 | const char *p, *pe; |
| 37 | |
| 38 | #define MKQUERY_ADDB(b) *rqp++= (b) |
| 39 | #define MKQUERY_ADDW(w) (MKQUERY_ADDB(((w)>>8)&0x0ff), MKQUERY_ADDB((w)&0x0ff)) |
| 40 | |
| 41 | vb->used= 0; |
| 42 | if (!adns__vbuf_ensure(vb,DNS_HDRSIZE+strlen(owner)+1+5)) |
| 43 | return adns_s_nolocalmem; |
| 44 | rqp= vb->buf; |
| 45 | |
| 46 | *id_r= id= (ads->nextid++) & 0x0ffff; |
| 47 | |
| 48 | MKQUERY_ADDW(id); |
| 49 | MKQUERY_ADDB(0x01); /* QR=Q(0), OPCODE=QUERY(0000), !AA, !TC, RD */ |
| 50 | MKQUERY_ADDB(0x00); /* !RA, Z=000, RCODE=NOERROR(0000) */ |
| 51 | MKQUERY_ADDW(1); /* QDCOUNT=1 */ |
| 52 | MKQUERY_ADDW(0); /* ANCOUNT=0 */ |
| 53 | MKQUERY_ADDW(0); /* NSCOUNT=0 */ |
| 54 | MKQUERY_ADDW(0); /* ARCOUNT=0 */ |
| 55 | p= owner; pe= owner+ol; |
| 56 | nlabs= 0; |
| 57 | if (!*p) return adns_s_invalidquerydomain; |
| 58 | do { |
| 59 | ll= 0; |
| 60 | while (p!=pe && (c= *p++)!='.') { |
| 61 | if (c=='\\') { |
| 62 | if (!(flags & adns_qf_anyquote)) return adns_s_invalidquerydomain; |
| 63 | if (ctype_digit(p[0])) { |
| 64 | if (ctype_digit(p[1]) && ctype_digit(p[2])) { |
| 65 | c= (*p++ - '0')*100 + (*p++ - '0')*10 + (*p++ - '0'); |
| 66 | if (c >= 256) return adns_s_invalidquerydomain; |
| 67 | } else { |
| 68 | return adns_s_invalidquerydomain; |
| 69 | } |
| 70 | } else if (!(c= *p++)) { |
| 71 | return adns_s_invalidquerydomain; |
| 72 | } |
| 73 | } |
| 74 | if (!(flags & adns_qf_anyquote)) { |
| 75 | if (c == '-') { |
| 76 | if (!ll) return adns_s_invalidquerydomain; |
| 77 | } else if (!ctype_alpha(c) && !ctype_digit(c)) { |
| 78 | return adns_s_invalidquerydomain; |
| 79 | } |
| 80 | } |
| 81 | if (ll == sizeof(label)) return adns_s_invalidquerydomain; |
| 82 | label[ll++]= c; |
| 83 | } |
| 84 | if (!ll) return adns_s_invalidquerydomain; |
| 85 | if (nlabs++ > 63) return adns_s_domaintoolong; |
| 86 | MKQUERY_ADDB(ll); |
| 87 | memcpy(rqp,label,ll); rqp+= ll; |
| 88 | } while (p!=pe); |
| 89 | |
| 90 | MKQUERY_ADDB(0); |
| 91 | MKQUERY_ADDW(typei->type & adns__rrt_typemask); /* QTYPE */ |
| 92 | MKQUERY_ADDW(DNS_CLASS_IN); /* QCLASS=IN */ |
| 93 | |
| 94 | vb->used= rqp - vb->buf; |
| 95 | assert(vb->used <= vb->avail); |
| 96 | |
| 97 | return adns_s_ok; |
| 98 | } |
| 99 | |
| 100 | void adns__query_tcp(adns_query qu, struct timeval now) { |
| 101 | byte length[2]; |
| 102 | struct iovec iov[2]; |
| 103 | int wr, r; |
| 104 | adns_state ads; |
| 105 | |
| 106 | if (qu->ads->tcpstate != server_ok) return; |
| 107 | |
| 108 | length[0]= (qu->query_dglen&0x0ff00U) >>8; |
| 109 | length[1]= (qu->query_dglen&0x0ff); |
| 110 | |
| 111 | ads= qu->ads; |
| 112 | if (!adns__vbuf_ensure(&ads->tcpsend,ads->tcpsend.used+qu->query_dglen+2)) return; |
| 113 | |
| 114 | timevaladd(&now,TCPMS); |
| 115 | qu->timeout= now; |
| 116 | qu->state= query_tcpsent; |
| 117 | LIST_LINK_TAIL(ads->timew,qu); |
| 118 | |
| 119 | if (ads->tcpsend.used) { |
| 120 | wr= 0; |
| 121 | } else { |
| 122 | iov[0].iov_base= length; |
| 123 | iov[0].iov_len= 2; |
| 124 | iov[1].iov_base= qu->query_dgram; |
| 125 | iov[1].iov_len= qu->query_dglen; |
| 126 | wr= writev(qu->ads->tcpsocket,iov,2); |
| 127 | if (wr < 0) { |
| 128 | if (!(errno == EAGAIN || errno == EINTR || errno == ENOSPC || |
| 129 | errno == ENOBUFS || errno == ENOMEM)) { |
| 130 | adns__tcp_broken(ads,"write",strerror(errno)); |
| 131 | return; |
| 132 | } |
| 133 | wr= 0; |
| 134 | } |
| 135 | } |
| 136 | |
| 137 | if (wr<2) { |
| 138 | r= adns__vbuf_append(&ads->tcpsend,length,2-wr); assert(r); |
| 139 | wr= 0; |
| 140 | } else { |
| 141 | wr-= 2; |
| 142 | } |
| 143 | if (wr<qu->query_dglen) { |
| 144 | r= adns__vbuf_append(&ads->tcpsend,qu->query_dgram+wr,qu->query_dglen-wr); assert(r); |
| 145 | } |
| 146 | } |
| 147 | |
| 148 | static void query_usetcp(adns_query qu, struct timeval now) { |
| 149 | timevaladd(&now,TCPMS); |
| 150 | qu->timeout= now; |
| 151 | qu->state= query_tcpwait; |
| 152 | LIST_LINK_TAIL(qu->ads->timew,qu); |
| 153 | adns__query_tcp(qu,now); |
| 154 | adns__tcp_tryconnect(qu->ads,now); |
| 155 | } |
| 156 | |
| 157 | void adns__query_udp(adns_query qu, struct timeval now) { |
| 158 | struct sockaddr_in servaddr; |
| 159 | int serv, r; |
| 160 | adns_state ads; |
| 161 | |
| 162 | assert(qu->state == query_udp); |
| 163 | if ((qu->flags & adns_qf_usevc) || (qu->query_dglen > DNS_MAXUDP)) { |
| 164 | query_usetcp(qu,now); |
| 165 | return; |
| 166 | } |
| 167 | |
| 168 | if (qu->udpretries >= UDPMAXRETRIES) { |
| 169 | adns__query_fail(qu,adns_s_timeout); |
| 170 | return; |
| 171 | } |
| 172 | |
| 173 | serv= qu->udpnextserver; |
| 174 | memset(&servaddr,0,sizeof(servaddr)); |
| 175 | |
| 176 | ads= qu->ads; |
| 177 | servaddr.sin_family= AF_INET; |
| 178 | servaddr.sin_addr= ads->servers[serv].addr; |
| 179 | servaddr.sin_port= htons(DNS_PORT); |
| 180 | |
| 181 | r= sendto(ads->udpsocket,qu->query_dgram,qu->query_dglen,0,&servaddr,sizeof(servaddr)); |
| 182 | if (r<0 && errno == EMSGSIZE) { query_usetcp(qu,now); return; } |
| 183 | if (r<0) adns__warn(ads,serv,0,"sendto failed: %s",strerror(errno)); |
| 184 | |
| 185 | timevaladd(&now,UDPRETRYMS); |
| 186 | qu->timeout= now; |
| 187 | qu->udpsent |= (1<<serv); |
| 188 | qu->udpnextserver= (serv+1)%ads->nservers; |
| 189 | qu->udpretries++; |
| 190 | LIST_LINK_TAIL(ads->timew,qu); |
| 191 | } |