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1 | /**/ |
2 | |
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3 | #include <errno.h> |
4 | #include <string.h> |
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5 | #include <stdlib.h> |
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6 | |
7 | #include <sys/uio.h> |
8 | |
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9 | #include "internal.h" |
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10 | |
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11 | adns_status adns__mkquery(adns_state ads, const char *owner, int ol, int id, |
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12 | const typeinfo *typei, adns_queryflags flags) { |
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13 | /* Assembles a query packet in ads->rqbuf. */ |
14 | int ll, c, nlabs; |
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15 | byte label[255], *rqp; |
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16 | const char *p, *pe; |
17 | |
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18 | #define MKQUERY_ADDB(b) *rqp++= (b) |
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19 | #define MKQUERY_ADDW(w) (MKQUERY_ADDB(((w)>>8)&0x0ff), MKQUERY_ADDB((w)&0x0ff)) |
20 | |
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21 | if (!adns__vbuf_ensure(&ads->rqbuf,DNS_HDRSIZE+strlen(owner)+1+5)) |
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22 | return adns_s_nolocalmem; |
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23 | rqp= ads->rqbuf.buf; |
24 | |
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25 | MKQUERY_ADDW(id); |
26 | MKQUERY_ADDB(0x01); /* QR=Q(0), OPCODE=QUERY(0000), !AA, !TC, RD */ |
27 | MKQUERY_ADDB(0x00); /* !RA, Z=000, RCODE=NOERROR(0000) */ |
28 | MKQUERY_ADDW(1); /* QDCOUNT=1 */ |
29 | MKQUERY_ADDW(0); /* ANCOUNT=0 */ |
30 | MKQUERY_ADDW(0); /* NSCOUNT=0 */ |
31 | MKQUERY_ADDW(0); /* ARCOUNT=0 */ |
32 | p= owner; pe= owner+ol; |
33 | nlabs= 0; |
34 | if (!*p) return adns_s_invaliddomain; |
35 | do { |
36 | ll= 0; |
37 | while (p!=pe && (c= *p++)!='.') { |
38 | if (c=='\\') { |
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39 | if (!(flags & adns_qf_anyquote)) return adns_s_invaliddomain; |
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40 | if (ctype_digit(p[0])) { |
41 | if (ctype_digit(p[1]) && ctype_digit(p[2])) { |
42 | c= (*p++ - '0')*100 + (*p++ - '0')*10 + (*p++ - '0'); |
43 | if (c >= 256) return adns_s_invaliddomain; |
44 | } else { |
45 | return adns_s_invaliddomain; |
46 | } |
47 | } else if (!(c= *p++)) { |
48 | return adns_s_invaliddomain; |
49 | } |
50 | } |
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51 | if (!(flags & adns_qf_anyquote)) { |
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52 | if (ctype_digit(c) || c == '-') { |
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53 | if (!ll) return adns_s_invaliddomain; |
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54 | } else if (!ctype_alpha(c)) { |
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55 | return adns_s_invaliddomain; |
56 | } |
57 | } |
58 | if (ll == sizeof(label)) return adns_s_invaliddomain; |
59 | label[ll++]= c; |
60 | } |
61 | if (!ll) return adns_s_invaliddomain; |
62 | if (nlabs++ > 63) return adns_s_invaliddomain; |
63 | MKQUERY_ADDB(ll); |
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64 | memcpy(rqp,label,ll); rqp+= ll; |
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65 | } while (p!=pe); |
66 | |
67 | MKQUERY_ADDB(0); |
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68 | MKQUERY_ADDW(typei->type & adns__rrt_typemask); /* QTYPE */ |
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69 | MKQUERY_ADDW(DNS_CLASS_IN); /* QCLASS=IN */ |
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70 | |
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71 | ads->rqbuf.used= rqp - ads->rqbuf.buf; |
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72 | assert(ads->rqbuf.used <= ads->rqbuf.avail); |
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73 | |
74 | return adns_s_ok; |
75 | } |
76 | |
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77 | void adns__query_tcp(adns_state ads, adns_query qu, struct timeval now) { |
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78 | /* Query must be in state tcpwait/timew; it will be moved to a new state |
79 | * if possible and no further processing can be done on it for now. |
80 | * (Resulting state is one of tcpwait/timew (if server not connected), |
81 | * tcpsent/timew, child/childw or done/output.) |
82 | * |
83 | * adns__tcp_tryconnect should already have been called - _tcp |
84 | * will only use an existing connection (if there is one), which it |
85 | * may break. If the conn list lost then the caller is responsible for any |
86 | * reestablishment and retry. |
87 | */ |
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88 | byte length[2]; |
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89 | struct iovec iov[2]; |
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90 | int wr, r; |
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91 | |
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92 | if (ads->tcpstate != server_ok) return; |
93 | |
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94 | length[0]= (qu->querylen&0x0ff00U) >>8; |
95 | length[1]= (qu->querylen&0x0ff); |
96 | |
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97 | if (!adns__vbuf_ensure(&ads->tcpsend,ads->tcpsend.used+qu->querylen+2)) return; |
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98 | |
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99 | timevaladd(&now,TCPMS); |
100 | qu->timeout= now; |
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101 | qu->state= query_tcpsent; |
102 | LIST_LINK_TAIL(ads->timew,qu); |
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103 | |
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104 | if (ads->tcpsend.used) { |
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105 | wr= 0; |
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106 | } else { |
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107 | iov[0].iov_base= length; |
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108 | iov[0].iov_len= 2; |
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109 | iov[1].iov_base= qu->querymsg; |
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110 | iov[1].iov_len= qu->querylen; |
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111 | wr= writev(ads->tcpsocket,iov,2); |
112 | if (wr < 0) { |
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113 | if (!(errno == EAGAIN || errno == EINTR || errno == ENOSPC || |
114 | errno == ENOBUFS || errno == ENOMEM)) { |
115 | adns__tcp_broken(ads,"write",strerror(errno)); |
116 | return; |
117 | } |
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118 | wr= 0; |
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119 | } |
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120 | } |
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121 | |
122 | if (wr<2) { |
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123 | r= adns__vbuf_append(&ads->tcpsend,length,2-wr); assert(r); |
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124 | wr= 0; |
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125 | } else { |
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126 | wr-= 2; |
127 | } |
128 | if (wr<qu->querylen) { |
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129 | r= adns__vbuf_append(&ads->tcpsend,qu->querymsg+wr,qu->querylen-wr); assert(r); |
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130 | } |
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131 | } |
132 | |
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133 | static void query_usetcp(adns_state ads, adns_query qu, struct timeval now) { |
134 | timevaladd(&now,TCPMS); |
135 | qu->timeout= now; |
136 | qu->state= query_tcpwait; |
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137 | LIST_LINK_TAIL(ads->timew,qu); |
138 | adns__query_tcp(ads,qu,now); |
139 | adns__tcp_tryconnect(ads,now); |
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140 | } |
141 | |
142 | void adns__query_udp(adns_state ads, adns_query qu, struct timeval now) { |
143 | /* Query must be in state udp/NONE; it will be moved to a new state, |
144 | * and no further processing can be done on it for now. |
145 | * (Resulting state is one of udp/timew, tcpwait/timew (if server not connected), |
146 | * tcpsent/timew, child/childw or done/output.) |
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147 | */ |
148 | struct sockaddr_in servaddr; |
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149 | int serv, r; |
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150 | |
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151 | assert(qu->state == query_udp); |
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152 | if ((qu->flags & adns_qf_usevc) || (qu->querylen > DNS_MAXUDP)) { |
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153 | query_usetcp(ads,qu,now); |
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154 | return; |
155 | } |
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156 | |
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157 | if (qu->udpretries >= UDPMAXRETRIES) { |
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158 | adns__query_fail(ads,qu,adns_s_timeout); |
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159 | return; |
160 | } |
161 | |
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162 | serv= qu->udpnextserver; |
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163 | memset(&servaddr,0,sizeof(servaddr)); |
164 | servaddr.sin_family= AF_INET; |
165 | servaddr.sin_addr= ads->servers[serv].addr; |
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166 | servaddr.sin_port= htons(DNS_PORT); |
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167 | |
168 | r= sendto(ads->udpsocket,qu->querymsg,qu->querylen,0,&servaddr,sizeof(servaddr)); |
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169 | if (r<0 && errno == EMSGSIZE) { query_usetcp(ads,qu,now); return; } |
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170 | if (r<0) adns__warn(ads,serv,"sendto failed: %s",strerror(errno)); |
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171 | |
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172 | timevaladd(&now,UDPRETRYMS); |
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173 | qu->timeout= now; |
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174 | qu->udpsent |= (1<<serv); |
175 | qu->udpnextserver= (serv+1)%ads->nservers; |
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176 | qu->udpretries++; |
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177 | LIST_LINK_TAIL(ads->timew,qu); |
178 | } |
179 | |
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180 | static void adns__query_done(adns_state ads, adns_query qu) { |
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181 | adns_answer *ans; |
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182 | allocnode *an, *ann; |
183 | |
184 | qu->answer= ans= realloc(qu->answer, |
185 | MEM_ROUND(MEM_ROUND(sizeof(*ans)) + |
186 | qu->interim_allocd)); |
187 | qu->final_used= MEM_ROUND(sizeof(*ans)); |
188 | |
189 | adns__makefinal_str(qu,&ans->cname); |
190 | if (ans->nrrs) { |
191 | adns__makefinal_block(qu,&ans->rrs.untyped,ans->rrsz*ans->nrrs); |
192 | for (i=0; i<ans->nrrs; i++) |
193 | qu->typei->makefinal(ads,qu,ans->rrs.bytes+ans->rrsz*i); |
194 | } |
195 | |
196 | for (an= qu->allocations; an; an= ann) { ann= an->next; free(an); } |
197 | |
198 | adns__vbuf_free(&qu->vb); |
199 | |
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200 | qu->id= -1; |
201 | LIST_LINK_TAIL(ads->output,qu); |
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202 | } |
203 | |
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204 | void adns__reset_cnameonly(adns_state ads, adns_query qu) { |
205 | qu->answer->nrrs= 0; |
206 | qu->answer->rrs= 0; |
207 | qu->permalloclen= qu->answer->cname ? MEM_ROUND(strlen(qu->answer->cname)+1) : 0; |
208 | } |
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209 | |
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210 | void adns__query_fail(adns_state ads, adns_query qu, adns_status stat) { |
211 | adns__reset_cnameonly(ads,qu); |
212 | qu->answer->status= stat; |
213 | qu->answer->type= qu->type; |
214 | adns__query_done(ads,qu,stat); |
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215 | } |