| 1 | /* |
| 2 | * transmit.c |
| 3 | * - construct queries |
| 4 | * - send queries |
| 5 | */ |
| 6 | /* |
| 7 | * This file is part of adns, which is |
| 8 | * Copyright (C) 1997-2000,2003,2006,2014 Ian Jackson |
| 9 | * Copyright (C) 2014 Mark Wooding |
| 10 | * Copyright (C) 1999-2000,2003,2006 Tony Finch |
| 11 | * Copyright (C) 1991 Massachusetts Institute of Technology |
| 12 | * (See the file INSTALL for full details.) |
| 13 | * |
| 14 | * This program is free software; you can redistribute it and/or modify |
| 15 | * it under the terms of the GNU General Public License as published by |
| 16 | * the Free Software Foundation; either version 3, or (at your option) |
| 17 | * any later version. |
| 18 | * |
| 19 | * This program is distributed in the hope that it will be useful, |
| 20 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 21 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 22 | * GNU General Public License for more details. |
| 23 | * |
| 24 | * You should have received a copy of the GNU General Public License |
| 25 | * along with this program; if not, write to the Free Software Foundation. |
| 26 | */ |
| 27 | |
| 28 | #include <errno.h> |
| 29 | |
| 30 | #include <sys/types.h> |
| 31 | #include <sys/uio.h> |
| 32 | |
| 33 | #include "internal.h" |
| 34 | #include "tvarith.h" |
| 35 | |
| 36 | #define MKQUERY_START(vb) (rqp= (vb)->buf+(vb)->used) |
| 37 | #define MKQUERY_ADDB(b) *rqp++= (b) |
| 38 | #define MKQUERY_ADDW(w) (MKQUERY_ADDB(((w)>>8)&0x0ff), MKQUERY_ADDB((w)&0x0ff)) |
| 39 | #define MKQUERY_STOP(vb) ((vb)->used= rqp-(vb)->buf) |
| 40 | |
| 41 | static adns_status mkquery_header(adns_state ads, vbuf *vb, |
| 42 | int *id_r, int qdlen) { |
| 43 | int id; |
| 44 | byte *rqp; |
| 45 | |
| 46 | if (!adns__vbuf_ensure(vb,DNS_HDRSIZE+qdlen+4)) return adns_s_nomemory; |
| 47 | |
| 48 | vb->used= 0; |
| 49 | MKQUERY_START(vb); |
| 50 | |
| 51 | *id_r= id= (ads->nextid++) & 0x0ffff; |
| 52 | MKQUERY_ADDW(id); |
| 53 | MKQUERY_ADDB(0x01); /* QR=Q(0), OPCODE=QUERY(0000), !AA, !TC, RD */ |
| 54 | MKQUERY_ADDB(0x00); /* !RA, Z=000, RCODE=NOERROR(0000) */ |
| 55 | MKQUERY_ADDW(1); /* QDCOUNT=1 */ |
| 56 | MKQUERY_ADDW(0); /* ANCOUNT=0 */ |
| 57 | MKQUERY_ADDW(0); /* NSCOUNT=0 */ |
| 58 | MKQUERY_ADDW(0); /* ARCOUNT=0 */ |
| 59 | |
| 60 | MKQUERY_STOP(vb); |
| 61 | |
| 62 | return adns_s_ok; |
| 63 | } |
| 64 | |
| 65 | static adns_status mkquery_footer(vbuf *vb, adns_rrtype type) { |
| 66 | byte *rqp; |
| 67 | |
| 68 | MKQUERY_START(vb); |
| 69 | MKQUERY_ADDW(type & adns_rrt_typemask); /* QTYPE */ |
| 70 | MKQUERY_ADDW(DNS_CLASS_IN); /* QCLASS=IN */ |
| 71 | MKQUERY_STOP(vb); |
| 72 | assert(vb->used <= vb->avail); |
| 73 | |
| 74 | return adns_s_ok; |
| 75 | } |
| 76 | |
| 77 | static adns_status qdparselabel(adns_state ads, |
| 78 | const char **p_io, const char *pe, |
| 79 | char label_r[], int *ll_io, |
| 80 | adns_queryflags flags) { |
| 81 | int ll, c; |
| 82 | const char *p; |
| 83 | |
| 84 | ll= 0; |
| 85 | p= *p_io; |
| 86 | |
| 87 | while (p!=pe && (c= *p++)!='.') { |
| 88 | if (c=='\\') { |
| 89 | if (!(flags & adns_qf_quoteok_query)) return adns_s_querydomaininvalid; |
| 90 | if (ctype_digit(p[0])) { |
| 91 | if (p+1==pe || p+2==pe) return adns_s_querydomaininvalid; |
| 92 | if (ctype_digit(p[1]) && ctype_digit(p[2])) { |
| 93 | c= (*p++ - '0')*100; |
| 94 | c += (*p++ - '0')*10; |
| 95 | c += (*p++ - '0'); |
| 96 | if (c >= 256) return adns_s_querydomaininvalid; |
| 97 | } else { |
| 98 | return adns_s_querydomaininvalid; |
| 99 | } |
| 100 | } else if (!(c= *p++)) { |
| 101 | return adns_s_querydomaininvalid; |
| 102 | } |
| 103 | } |
| 104 | if (ll == *ll_io) return adns_s_querydomaininvalid; |
| 105 | label_r[ll++]= c; |
| 106 | } |
| 107 | |
| 108 | *p_io= p; |
| 109 | *ll_io= ll; |
| 110 | return adns_s_ok; |
| 111 | } |
| 112 | |
| 113 | adns_status adns__mkquery(adns_state ads, vbuf *vb, int *id_r, |
| 114 | const char *owner, int ol, |
| 115 | const typeinfo *typei, adns_rrtype type, |
| 116 | adns_queryflags flags) { |
| 117 | int ll, nbytes; |
| 118 | byte label[255]; |
| 119 | byte *rqp; |
| 120 | const char *p, *pe; |
| 121 | adns_status st; |
| 122 | |
| 123 | st= mkquery_header(ads,vb,id_r,ol+2); if (st) return st; |
| 124 | |
| 125 | MKQUERY_START(vb); |
| 126 | |
| 127 | p= owner; pe= owner+ol; |
| 128 | nbytes= 0; |
| 129 | while (p!=pe) { |
| 130 | ll= sizeof(label); |
| 131 | st= qdparselabel(ads, &p,pe, label, &ll, flags); |
| 132 | if (st) return st; |
| 133 | if (!ll) return adns_s_querydomaininvalid; |
| 134 | if (ll > DNS_MAXLABEL) return adns_s_querydomaintoolong; |
| 135 | nbytes+= ll+1; |
| 136 | if (nbytes >= DNS_MAXDOMAIN) return adns_s_querydomaintoolong; |
| 137 | MKQUERY_ADDB(ll); |
| 138 | memcpy(rqp,label,ll); rqp+= ll; |
| 139 | } |
| 140 | MKQUERY_ADDB(0); |
| 141 | |
| 142 | MKQUERY_STOP(vb); |
| 143 | |
| 144 | st= mkquery_footer(vb,type); |
| 145 | |
| 146 | return adns_s_ok; |
| 147 | } |
| 148 | |
| 149 | adns_status adns__mkquery_frdgram(adns_state ads, vbuf *vb, int *id_r, |
| 150 | const byte *qd_dgram, int qd_dglen, |
| 151 | int qd_begin, |
| 152 | adns_rrtype type, adns_queryflags flags) { |
| 153 | byte *rqp; |
| 154 | findlabel_state fls; |
| 155 | int lablen, labstart; |
| 156 | adns_status st; |
| 157 | |
| 158 | st= mkquery_header(ads,vb,id_r,qd_dglen); if (st) return st; |
| 159 | |
| 160 | MKQUERY_START(vb); |
| 161 | |
| 162 | adns__findlabel_start(&fls,ads,-1,0,qd_dgram,qd_dglen,qd_dglen,qd_begin,0); |
| 163 | for (;;) { |
| 164 | st= adns__findlabel_next(&fls,&lablen,&labstart); assert(!st); |
| 165 | if (!lablen) break; |
| 166 | assert(lablen<255); |
| 167 | MKQUERY_ADDB(lablen); |
| 168 | memcpy(rqp,qd_dgram+labstart,lablen); |
| 169 | rqp+= lablen; |
| 170 | } |
| 171 | MKQUERY_ADDB(0); |
| 172 | |
| 173 | MKQUERY_STOP(vb); |
| 174 | |
| 175 | st= mkquery_footer(vb,type); |
| 176 | |
| 177 | return adns_s_ok; |
| 178 | } |
| 179 | |
| 180 | void adns__querysend_tcp(adns_query qu, struct timeval now) { |
| 181 | byte length[2]; |
| 182 | struct iovec iov[2]; |
| 183 | int wr, r; |
| 184 | adns_state ads; |
| 185 | |
| 186 | if (qu->ads->tcpstate != server_ok) return; |
| 187 | |
| 188 | assert(qu->state == query_tcpw); |
| 189 | |
| 190 | length[0]= (qu->query_dglen&0x0ff00U) >>8; |
| 191 | length[1]= (qu->query_dglen&0x0ff); |
| 192 | |
| 193 | ads= qu->ads; |
| 194 | if (!adns__vbuf_ensure(&ads->tcpsend,ads->tcpsend.used+qu->query_dglen+2)) |
| 195 | return; |
| 196 | |
| 197 | qu->retries++; |
| 198 | |
| 199 | /* Reset idle timeout. */ |
| 200 | ads->tcptimeout.tv_sec= ads->tcptimeout.tv_usec= 0; |
| 201 | |
| 202 | if (ads->tcpsend.used) { |
| 203 | wr= 0; |
| 204 | } else { |
| 205 | iov[0].iov_base= length; |
| 206 | iov[0].iov_len= 2; |
| 207 | iov[1].iov_base= qu->query_dgram; |
| 208 | iov[1].iov_len= qu->query_dglen; |
| 209 | adns__sigpipe_protect(qu->ads); |
| 210 | wr= writev(qu->ads->tcpsocket,iov,2); |
| 211 | adns__sigpipe_unprotect(qu->ads); |
| 212 | if (wr < 0) { |
| 213 | if (!(errno == EAGAIN || errno == EINTR || errno == ENOSPC || |
| 214 | errno == ENOBUFS || errno == ENOMEM)) { |
| 215 | adns__tcp_broken(ads,"write",strerror(errno)); |
| 216 | return; |
| 217 | } |
| 218 | wr= 0; |
| 219 | } |
| 220 | } |
| 221 | |
| 222 | if (wr<2) { |
| 223 | r= adns__vbuf_append(&ads->tcpsend,length,2-wr); assert(r); |
| 224 | wr= 0; |
| 225 | } else { |
| 226 | wr-= 2; |
| 227 | } |
| 228 | if (wr<qu->query_dglen) { |
| 229 | r= adns__vbuf_append(&ads->tcpsend,qu->query_dgram+wr,qu->query_dglen-wr); |
| 230 | assert(r); |
| 231 | } |
| 232 | } |
| 233 | |
| 234 | static void query_usetcp(adns_query qu, struct timeval now) { |
| 235 | qu->state= query_tcpw; |
| 236 | qu->timeout= now; |
| 237 | timevaladd(&qu->timeout,TCPWAITMS); |
| 238 | LIST_LINK_TAIL(qu->ads->tcpw,qu); |
| 239 | adns__querysend_tcp(qu,now); |
| 240 | adns__tcp_tryconnect(qu->ads,now); |
| 241 | } |
| 242 | |
| 243 | struct udpsocket *adns__udpsocket_by_af(adns_state ads, int af) { |
| 244 | int i; |
| 245 | for (i=0; i<ads->nudpsockets; i++) |
| 246 | if (ads->udpsockets[i].af == af) return &ads->udpsockets[i]; |
| 247 | return 0; |
| 248 | } |
| 249 | |
| 250 | void adns__query_send(adns_query qu, struct timeval now) { |
| 251 | int serv, r; |
| 252 | adns_state ads; |
| 253 | struct udpsocket *udp; |
| 254 | adns_rr_addr *addr; |
| 255 | |
| 256 | assert(qu->state == query_tosend); |
| 257 | if ((qu->flags & adns_qf_usevc) || (qu->query_dglen > DNS_MAXUDP)) { |
| 258 | query_usetcp(qu,now); |
| 259 | return; |
| 260 | } |
| 261 | |
| 262 | if (qu->retries >= UDPMAXRETRIES) { |
| 263 | adns__query_fail(qu,adns_s_timeout); |
| 264 | return; |
| 265 | } |
| 266 | |
| 267 | ads= qu->ads; |
| 268 | serv= qu->udpnextserver; |
| 269 | addr= &ads->servers[serv]; |
| 270 | udp= adns__udpsocket_by_af(ads, addr->addr.sa.sa_family); |
| 271 | assert(udp); |
| 272 | |
| 273 | r= sendto(udp->fd,qu->query_dgram,qu->query_dglen,0, |
| 274 | &addr->addr.sa,addr->len); |
| 275 | if (r<0 && errno == EMSGSIZE) { |
| 276 | qu->retries= 0; |
| 277 | query_usetcp(qu,now); |
| 278 | return; |
| 279 | } |
| 280 | if (r<0 && errno != EAGAIN) |
| 281 | adns__warn(ads,serv,0,"sendto failed: %s",strerror(errno)); |
| 282 | |
| 283 | qu->timeout= now; |
| 284 | timevaladd(&qu->timeout,UDPRETRYMS); |
| 285 | qu->udpsent |= (1<<serv); |
| 286 | qu->udpnextserver= (serv+1)%ads->nservers; |
| 287 | qu->retries++; |
| 288 | LIST_LINK_TAIL(ads->udpw,qu); |
| 289 | } |