mdw@git.distorted.org.uk Git - adns/blob - src/query.c

   1 /**/
   2
   3 #include "internal.h"
   4
   5 adns_status adns__mkquery(adns_state ads, const char *owner, int ol, int id,
   6                           adns_rrtype type, adns_queryflags flags) {
   7   /* Assembles a query packet in ads->rqbuf. */
   8   int ll, c, nlabs;
   9   unsigned char label[255], *rqp;
  10   const char *p, *pe;
  11
  12 #define MKQUERY_ADDB(b) *rqp++= (b)
  13 #define MKQUERY_ADDW(w) (MKQUERY_ADDB(((w)>>8)&0x0ff), MKQUERY_ADDB((w)&0x0ff))
  14
  15   if (!vbuf_ensure(&ads->rqbuf,12+strlen(owner)+3)) return adns_s_nolocalmem;
  16   rqp= ads->rqbuf.buf;
  17
  18   MKQUERY_ADDW(id);
  19   MKQUERY_ADDB(0x01); /* QR=Q(0), OPCODE=QUERY(0000), !AA, !TC, RD */
  20   MKQUERY_ADDB(0x00); /* !RA, Z=000, RCODE=NOERROR(0000) */
  21   MKQUERY_ADDW(1); /* QDCOUNT=1 */
  22   MKQUERY_ADDW(0); /* ANCOUNT=0 */
  23   MKQUERY_ADDW(0); /* NSCOUNT=0 */
  24   MKQUERY_ADDW(0); /* ARCOUNT=0 */
  25   p= owner; pe= owner+ol;
  26   nlabs= 0;
  27   if (!*p) return adns_s_invaliddomain;
  28   do {
  29     ll= 0;
  30     while (p!=pe && (c= *p++)!='.') {
  31       if (c=='\\') {
  32         if (!(flags & adns_f_anyquote)) return adns_s_invaliddomain;
  33         if (ctype_digit(p[0])) {
  34           if (ctype_digit(p[1]) && ctype_digit(p[2])) {
  35             c= (*p++ - '0')*100 + (*p++ - '0')*10 + (*p++ - '0');
  36             if (c >= 256) return adns_s_invaliddomain;
  37           } else {
  38             return adns_s_invaliddomain;
  39           }
  40         } else if (!(c= *p++)) {
  41           return adns_s_invaliddomain;
  42         }
  43       }
  44       if (!(flags & adns_f_anyquote)) {
  45         if (ctype_digit(c) || c == '-') {
  46           if (!ll) return adns_s_invaliddomain;
  47         } else if ((c < 'a' || c > 'z') && (c < 'A' && c > 'Z')) {
  48           return adns_s_invaliddomain;
  49         }
  50       }
  51       if (ll == sizeof(label)) return adns_s_invaliddomain;
  52       label[ll++]= c;
  53     }
  54     if (!ll) return adns_s_invaliddomain;
  55     if (nlabs++ > 63) return adns_s_invaliddomain;
  56     MKQUERY_ADDB(ll);
  57     memcpy(rqp,label,ll); rqp+= ll;
  58   } while (p!=pe);
  59
  60   MKQUERY_ADDB(0);
  61   MKQUERY_ADDW(type & adns__rrt_typemask); /* QTYPE */
  62   MKQUERY_ADDW(1); /* QCLASS=IN */
  63
  64   ads->rqbuf.used= rqp - ads->rqbuf.used;
  65   assert(ads->rqbuf.used < ads->rqbuf.avail);
  66
  67   return adns_s_ok;
  68 }
  69
  70 void adns__query_tcp(adns_state ads, adns_query qu) {
  71   /* Query must be in state tcpwait/timew; it will be moved to a new state
  72    * if possible and no further processing can be done on it for now.
  73    * (Resulting state is one of tcpwait/timew (if server not connected),
  74    *  tcpsent/timew, child/childw or done/output.)
  75    *
  76    * adns__tcp_tryconnect should already have been called - _tcp
  77    * will only use an existing connection (if there is one), which it
  78    * may break.  If the conn list lost then the caller is responsible for any
  79    * reestablishment and retry.
  80    */
  81   unsigned char length[2];
  82   struct iovec iov[2];
  83
  84   if (ads->tcpstate != server_ok) return;
  85
  86   length[0]= (qu->querylen&0x0ff00U) >>8;
  87   length[1]= (qu->querylen&0x0ff);
  88
  89   if (!vbuf_ensure(&ads->tcpsend,ads->tcpsend.used+qu->querylen+2)) return;
  90
  91   timevaladd(&now,TCPMS);
  92   qu->timeout= now;
  93   qu->senttcpserver= ads->tcpserver;
  94   DLIST_LINKTAIL(ads->timew,qu);
  95
  96   if (ads->opbufused) {
  97     wr= 0;
  98   } else {
  99     iov[0].iovbase= length;
 100     iov[0].iov_len= 2;
 101     iov[1].iovbase= qu->querymsg;
 102     iov[1].iov_len= qu->querylen;
 103     wr= writev(ads->tcpsocket,iov,2);
 104     if (wr < 0) {
 105       if (!(errno == EAGAIN || errno == EINTR || errno == ENOSPC ||
 106             errno == ENOBUFS || errno == ENOMEM)) {
 107         adns__tcp_broken(ads,"write",strerror(errno));
 108         return;
 109       }
 110       wr= 0;
 111     }
 112   }
 113
 114   if (wr<2) {
 115     r= vbuf_append(&ads->tcpsend,length,2-wr); assert(r);
 116     wr= 0;
 117   } esle {
 118     wr-= 2;
 119   }
 120   if (wr<qu->querylen) {
 121     r= vbuf_append(&ads->tcpsend,qu->querymsg+wr,qu->querylen-wr); assert(r);
 122   }
 123 }
 124
 125 static void query_usetcp(adns_state ads, adns_query qu, struct timeval now) {
 126   timevaladd(&now,TCPMS);
 127   qu->timeout= now;
 128   qu->state= query_tcpwait;
 129   DLIST_LINKTAIL(ads->timew,qu);
 130   adns__query_tcp(ads,qu);
 131   adns__tcp_tryconnect(ads);
 132 }
 133
 134 void adns__query_udp(adns_state ads, adns_query qu, struct timeval now) {
 135   /* Query must be in state udp/NONE; it will be moved to a new state,
 136    * and no further processing can be done on it for now.
 137    * (Resulting state is one of udp/timew, tcpwait/timew (if server not connected),
 138    *  tcpsent/timew, child/childw or done/output.)
 139    */
 140   struct sockaddr_in servaddr;
 141   int serv;
 142
 143   assert(qu->state == query_udp);
 144   if ((qu->flags & adns_f_usevc) ||
 145       (qu->querylen > UDPMAXDGRAM)) {
 146     query_usetcp(ads,qu,now);
 147     return;
 148   }
 149
 150   if (qu->udpretries >= UDPMAXRETRIES) {
 151     query_fail(ads,qu,adns_s_notresponding);
 152     return;
 153   }
 154
 155   serv= qu->nextudpserver;
 156   memset(&servaddr,0,sizeof(servaddr));
 157   servaddr.sin_family= AF_INET;
 158   servaddr.sin_addr= ads->servers[serv].addr;
 159   servaddr.sin_port= htons(NSPORT);
 160
 161   r= sendto(ads->udpsocket,qu->querymsg,qu->querylen,0,&servaddr,sizeof(servaddr));
 162   if (r<0 && errno == EMSGSIZE) { query_usetcp(ads,qu,now); return; }
 163   if (r<0) warn("sendto %s failed: %s",inet_ntoa(servaddr.sin_addr),strerror(errno));
 164
 165   timevaladd(&now,UDPRETRYMS);
 166   qu->timeout= now;
 167   qu->sentudp |= (1<<serv);
 168   qu->nextudpserver= (serv+1)%ads->nservers;
 169   qu->udpretries++;
 170   DLIST_LINKTAIL(ads->timew,qu);
 171 }
 172
 173 void adns__query_fail(adns_state ads, adns_query qu, adns_status stat) {
 174   adns_answer *ans;
 175
 176   ans= qu->answer;
 177   if (!ans) ans= malloc(sizeof(*qu->answer));
 178   if (ans) {
 179     ans->status= stat;
 180     ans->cname= 0;
 181     ans->type= qu->type;
 182     ans->nrrs= 0;
 183   }
 184   qu->answer= ans;
 185   qu->id= -1;
 186   LIST_LINK_TAIL(ads->output,qu);
 187 }