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1 | /**/ |
2 | |
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3 | #include <errno.h> |
4 | #include <string.h> |
5 | |
6 | #include <sys/uio.h> |
7 | |
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8 | #include "internal.h" |
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9 | |
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10 | adns_status adns__mkquery(adns_state ads, const char *owner, int ol, int id, |
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11 | adns_rrtype type, adns_queryflags flags) { |
12 | /* Assembles a query packet in ads->rqbuf. */ |
13 | int ll, c, nlabs; |
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14 | byte label[255], *rqp; |
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15 | const char *p, *pe; |
16 | |
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17 | #define MKQUERY_ADDB(b) *rqp++= (b) |
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18 | #define MKQUERY_ADDW(w) (MKQUERY_ADDB(((w)>>8)&0x0ff), MKQUERY_ADDB((w)&0x0ff)) |
19 | |
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20 | if (!adns__vbuf_ensure(&ads->rqbuf,DNSHDRSIZE+strlen(owner)+1+5)) |
21 | return adns_s_nolocalmem; |
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22 | rqp= ads->rqbuf.buf; |
23 | |
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24 | MKQUERY_ADDW(id); |
25 | MKQUERY_ADDB(0x01); /* QR=Q(0), OPCODE=QUERY(0000), !AA, !TC, RD */ |
26 | MKQUERY_ADDB(0x00); /* !RA, Z=000, RCODE=NOERROR(0000) */ |
27 | MKQUERY_ADDW(1); /* QDCOUNT=1 */ |
28 | MKQUERY_ADDW(0); /* ANCOUNT=0 */ |
29 | MKQUERY_ADDW(0); /* NSCOUNT=0 */ |
30 | MKQUERY_ADDW(0); /* ARCOUNT=0 */ |
31 | p= owner; pe= owner+ol; |
32 | nlabs= 0; |
33 | if (!*p) return adns_s_invaliddomain; |
34 | do { |
35 | ll= 0; |
36 | while (p!=pe && (c= *p++)!='.') { |
37 | if (c=='\\') { |
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38 | if (!(flags & adns_qf_anyquote)) return adns_s_invaliddomain; |
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39 | if (ctype_digit(p[0])) { |
40 | if (ctype_digit(p[1]) && ctype_digit(p[2])) { |
41 | c= (*p++ - '0')*100 + (*p++ - '0')*10 + (*p++ - '0'); |
42 | if (c >= 256) return adns_s_invaliddomain; |
43 | } else { |
44 | return adns_s_invaliddomain; |
45 | } |
46 | } else if (!(c= *p++)) { |
47 | return adns_s_invaliddomain; |
48 | } |
49 | } |
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50 | if (!(flags & adns_qf_anyquote)) { |
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51 | if (ctype_digit(c) || c == '-') { |
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52 | if (!ll) return adns_s_invaliddomain; |
53 | } else if ((c < 'a' || c > 'z') && (c < 'A' && c > 'Z')) { |
54 | return adns_s_invaliddomain; |
55 | } |
56 | } |
57 | if (ll == sizeof(label)) return adns_s_invaliddomain; |
58 | label[ll++]= c; |
59 | } |
60 | if (!ll) return adns_s_invaliddomain; |
61 | if (nlabs++ > 63) return adns_s_invaliddomain; |
62 | MKQUERY_ADDB(ll); |
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63 | memcpy(rqp,label,ll); rqp+= ll; |
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64 | } while (p!=pe); |
65 | |
66 | MKQUERY_ADDB(0); |
67 | MKQUERY_ADDW(type & adns__rrt_typemask); /* QTYPE */ |
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68 | MKQUERY_ADDW(DNS_CLASS_IN); /* QCLASS=IN */ |
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69 | |
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70 | ads->rqbuf.used= rqp - ads->rqbuf.buf; |
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71 | assert(ads->rqbuf.used <= ads->rqbuf.avail); |
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72 | |
73 | return adns_s_ok; |
74 | } |
75 | |
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76 | void adns__query_tcp(adns_state ads, adns_query qu, struct timeval now) { |
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77 | /* Query must be in state tcpwait/timew; it will be moved to a new state |
78 | * if possible and no further processing can be done on it for now. |
79 | * (Resulting state is one of tcpwait/timew (if server not connected), |
80 | * tcpsent/timew, child/childw or done/output.) |
81 | * |
82 | * adns__tcp_tryconnect should already have been called - _tcp |
83 | * will only use an existing connection (if there is one), which it |
84 | * may break. If the conn list lost then the caller is responsible for any |
85 | * reestablishment and retry. |
86 | */ |
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87 | byte length[2]; |
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88 | struct iovec iov[2]; |
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89 | int wr, r; |
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90 | |
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91 | if (ads->tcpstate != server_ok) return; |
92 | |
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93 | length[0]= (qu->querylen&0x0ff00U) >>8; |
94 | length[1]= (qu->querylen&0x0ff); |
95 | |
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96 | if (!adns__vbuf_ensure(&ads->tcpsend,ads->tcpsend.used+qu->querylen+2)) return; |
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97 | |
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98 | timevaladd(&now,TCPMS); |
99 | qu->timeout= now; |
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100 | qu->state= query_tcpsent; |
101 | LIST_LINK_TAIL(ads->timew,qu); |
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102 | |
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103 | if (ads->tcpsend.used) { |
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104 | wr= 0; |
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105 | } else { |
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106 | iov[0].iov_base= length; |
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107 | iov[0].iov_len= 2; |
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108 | iov[1].iov_base= qu->querymsg; |
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109 | iov[1].iov_len= qu->querylen; |
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110 | wr= writev(ads->tcpsocket,iov,2); |
111 | if (wr < 0) { |
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112 | if (!(errno == EAGAIN || errno == EINTR || errno == ENOSPC || |
113 | errno == ENOBUFS || errno == ENOMEM)) { |
114 | adns__tcp_broken(ads,"write",strerror(errno)); |
115 | return; |
116 | } |
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117 | wr= 0; |
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118 | } |
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119 | } |
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120 | |
121 | if (wr<2) { |
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122 | r= adns__vbuf_append(&ads->tcpsend,length,2-wr); assert(r); |
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123 | wr= 0; |
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124 | } else { |
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125 | wr-= 2; |
126 | } |
127 | if (wr<qu->querylen) { |
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128 | r= adns__vbuf_append(&ads->tcpsend,qu->querymsg+wr,qu->querylen-wr); assert(r); |
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129 | } |
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130 | } |
131 | |
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132 | static void query_usetcp(adns_state ads, adns_query qu, struct timeval now) { |
133 | timevaladd(&now,TCPMS); |
134 | qu->timeout= now; |
135 | qu->state= query_tcpwait; |
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136 | LIST_LINK_TAIL(ads->timew,qu); |
137 | adns__query_tcp(ads,qu,now); |
138 | adns__tcp_tryconnect(ads,now); |
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139 | } |
140 | |
141 | void adns__query_udp(adns_state ads, adns_query qu, struct timeval now) { |
142 | /* Query must be in state udp/NONE; it will be moved to a new state, |
143 | * and no further processing can be done on it for now. |
144 | * (Resulting state is one of udp/timew, tcpwait/timew (if server not connected), |
145 | * tcpsent/timew, child/childw or done/output.) |
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146 | */ |
147 | struct sockaddr_in servaddr; |
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148 | int serv, r; |
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149 | |
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150 | assert(qu->state == query_udp); |
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151 | if ((qu->flags & adns_qf_usevc) || (qu->querylen > MAXUDPDGRAM)) { |
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152 | query_usetcp(ads,qu,now); |
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153 | return; |
154 | } |
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155 | |
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156 | if (qu->udpretries >= MAXUDPRETRIES) { |
157 | adns__query_fail(ads,qu,adns_s_timeout); |
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158 | return; |
159 | } |
160 | |
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161 | serv= qu->udpnextserver; |
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162 | memset(&servaddr,0,sizeof(servaddr)); |
163 | servaddr.sin_family= AF_INET; |
164 | servaddr.sin_addr= ads->servers[serv].addr; |
165 | servaddr.sin_port= htons(NSPORT); |
166 | |
167 | r= sendto(ads->udpsocket,qu->querymsg,qu->querylen,0,&servaddr,sizeof(servaddr)); |
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168 | if (r<0 && errno == EMSGSIZE) { query_usetcp(ads,qu,now); return; } |
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169 | if (r<0) adns__warn(ads,serv,"sendto failed: %s",strerror(errno)); |
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170 | |
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171 | timevaladd(&now,UDPRETRYMS); |
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172 | qu->timeout= now; |
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173 | qu->udpsent |= (1<<serv); |
174 | qu->udpnextserver= (serv+1)%ads->nservers; |
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175 | qu->udpretries++; |
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176 | LIST_LINK_TAIL(ads->timew,qu); |
177 | } |
178 | |
179 | void adns__query_nomem(adns_state ads, adns_query qu) { |
180 | qu->answer.used= 0; |
181 | qu->id= -1; |
182 | LIST_LINK_TAIL(ads->output,qu); |
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183 | } |
184 | |
185 | void adns__query_fail(adns_state ads, adns_query qu, adns_status stat) { |
186 | adns_answer *ans; |
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187 | |
188 | if (!adns__vbuf_ensure(&qu->answer,sizeof(adns_answer))) { |
189 | adns__query_nomem(ads,qu); |
190 | return; |
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191 | } |
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192 | ans= (adns_answer*)qu->answer.buf; |
193 | ans->status= stat; |
194 | ans->cname= 0; |
195 | ans->type= qu->type; |
196 | ans->nrrs= 0; |
197 | qu->answer.used= sizeof(adns_answer); |
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198 | qu->id= -1; |
199 | LIST_LINK_TAIL(ads->output,qu); |
200 | } |