chiark / gitweb /
changelog: finalise 0.6.1
[secnet.git] / resolver.c
1 /*
2  * This file is part of secnet.
3  * See README for full list of copyright holders.
4  *
5  * secnet is free software; you can redistribute it and/or modify it
6  * under the terms of the GNU General Public License as published by
7  * the Free Software Foundation; either version 3 of the License, or
8  * (at your option) any later version.
9  * 
10  * secnet is distributed in the hope that it will be useful, but
11  * WITHOUT ANY WARRANTY; without even the implied warranty of
12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
13  * General Public License for more details.
14  * 
15  * You should have received a copy of the GNU General Public License
16  * version 3 along with secnet; if not, see
17  * https://www.gnu.org/licenses/gpl.html.
18  */
19 /* Name resolution using adns */
20
21 #include <errno.h>
22 #include "secnet.h"
23 #include "util.h"
24 #ifndef HAVE_LIBADNS
25 #error secnet requires ADNS version 1.0 or above
26 #endif
27 #include <adns.h>
28 #include <arpa/inet.h>
29 #include <string.h>
30
31
32 struct adns {
33     closure_t cl;
34     struct resolver_if ops;
35     struct cloc loc;
36     adns_state ast;
37 };
38
39 struct query {
40     void *cst;
41     const char *name;
42     int port;
43     struct comm_if *comm;
44     resolve_answer_fn *answer;
45     adns_query query;
46 };
47
48 static resolve_request_fn resolve_request;
49 static bool_t resolve_request(void *sst, cstring_t name,
50                               int port, struct comm_if *comm,
51                               resolve_answer_fn *cb, void *cst)
52 {
53     struct adns *st=sst;
54     struct query *q;
55     int rv;
56     const int maxlitlen=
57 #ifdef CONFIG_IPV6
58         ADNS_ADDR2TEXT_BUFLEN*2
59 #else
60         50
61 #endif
62         ;
63     ssize_t l=strlen(name);
64     if (name[0]=='[' && l<maxlitlen && l>2 && name[l-1]==']') {
65         char trimmed[maxlitlen+1];
66         memcpy(trimmed,name+1,l-2);
67         trimmed[l-2]=0;
68         struct comm_addr ca;
69         ca.comm=comm;
70         ca.ix=-1;
71 #ifdef CONFIG_IPV6
72         socklen_t salen=sizeof(ca.ia);
73         rv=adns_text2addr(trimmed, port, adns_qf_addrlit_ipv4_quadonly,
74                           &ca.ia.sa, &salen);
75         assert(rv!=ENOSPC);
76         if (rv) {
77             char msg[250];
78             snprintf(msg,sizeof(msg),"invalid address literal: %s",
79                      strerror(rv));
80             msg[sizeof(msg)-1]=0;
81             cb(cst,0,0,0,name,msg);
82         } else {
83             cb(cst,&ca,1,1,name,0);
84         }
85 #else
86         ca.ia.sin.sin_family=AF_INET;
87         ca.ia.sin.sin_port=htons(port);
88         if (inet_aton(trimmed,&ca.ia.sin.sin_addr))
89             cb(cst,&ca,1,1,name,0);
90         else
91             cb(cst,0,0,0,name,"invalid IP address");
92 #endif
93         return True;
94     }
95
96     NEW(q);
97     q->cst=cst;
98     q->comm=comm;
99     q->port=port;
100     q->name=name;
101     q->answer=cb;
102
103     rv=adns_submit(st->ast, name, adns_r_addr, 0, q, &q->query);
104     if (rv) {
105         Message(M_WARNING,
106                 "resolver: failed to submit lookup for %s: %s",name,
107                 adns_strerror(rv));
108         free(q);
109         return False;
110     }
111
112     return True;
113 }
114
115 static int resolver_beforepoll(void *sst, struct pollfd *fds, int *nfds_io,
116                                int *timeout_io)
117 {
118     struct adns *st=sst;
119     return adns_beforepoll(st->ast, fds, nfds_io, timeout_io, tv_now);
120 }
121
122 static void resolver_afterpoll(void *sst, struct pollfd *fds, int nfds)
123 {
124     struct adns *st=sst;
125     adns_query aq;
126     adns_answer *ans;
127     void *qp;
128     struct query *q;
129     int rv;
130
131     adns_afterpoll(st->ast, fds, nfds, tv_now);
132
133     while (True) {
134         aq=NULL;
135         rv=adns_check(st->ast, &aq, &ans, &qp);
136         if (rv==0) {
137             q=qp;
138             if (ans->status!=adns_s_ok) {
139                 q->answer(q->cst,NULL,0,0,q->name,adns_strerror(ans->status));
140                 free(q);
141                 free(ans);
142             } else {
143                 int rslot, wslot, total;
144                 int ca_len=MIN(ans->nrrs,MAX_PEER_ADDRS);
145                 struct comm_addr ca_buf[ca_len];
146                 for (rslot=0, wslot=0, total=0;
147                      rslot<ans->nrrs;
148                      rslot++) {
149                     total++;
150                     if (!(wslot<ca_len)) continue;
151                     adns_rr_addr *ra=&ans->rrs.addr[rslot];
152                     struct comm_addr *ca=&ca_buf[wslot];
153                     ca->comm=q->comm;
154                     ca->ix=-1;
155                     assert(ra->len <= (int)sizeof(ca->ia));
156                     memcpy(&ca->ia,&ra->addr,ra->len);
157                     switch (ra->addr.sa.sa_family) {
158                     case AF_INET:
159                         assert(ra->len == sizeof(ca->ia.sin));
160                         ca->ia.sin.sin_port=htons(q->port);
161                         break;
162 #ifdef CONFIG_IPV6
163                     case AF_INET6:
164                         assert(ra->len == sizeof(ca->ia.sin6));
165                         ca->ia.sin6.sin6_port=htons(q->port);
166                         break;
167 #endif /*CONFIG_IPV6*/
168                     default:
169                         /* silently skip unexpected AFs from adns */
170                         continue;
171                     }
172                     wslot++;
173                 }
174                 q->answer(q->cst,ca_buf,wslot,total,q->name,0);
175                 free(q);
176                 free(ans);
177             }
178         } else if (rv==EAGAIN || rv==ESRCH) {
179             break;
180         } else {
181             fatal("resolver_afterpoll: adns_check() returned %d",rv);
182         }
183     }
184
185     return;
186 }
187
188 /* Initialise adns, using parameters supplied */
189 static list_t *adnsresolver_apply(closure_t *self, struct cloc loc,
190                                   dict_t *context, list_t *args)
191 {
192     struct adns *st;
193     dict_t *d;
194     item_t *i;
195     string_t conf;
196
197     NEW(st);
198     st->cl.description="adns";
199     st->cl.type=CL_RESOLVER;
200     st->cl.apply=NULL;
201     st->cl.interface=&st->ops;
202     st->loc=loc;
203     st->ops.st=st;
204     st->ops.request=resolve_request;
205
206     i=list_elem(args,0);
207     if (!i || i->type!=t_dict) {
208         cfgfatal(st->loc,"adns","first argument must be a dictionary\n");
209     }
210     d=i->data.dict;
211     conf=dict_read_string(d,"config",False,"adns",loc);
212
213     adns_initflags iflags = 0;
214 #if USE_MONOTONIC
215     iflags |= adns_if_monotonic;
216 #endif
217
218     if (conf) {
219         if (adns_init_strcfg(&st->ast, iflags, 0, conf)) {
220             fatal_perror("Failed to initialise ADNS");
221         }
222     } else {
223         if (adns_init(&st->ast, iflags, 0)) {
224             fatal_perror("Failed to initialise ADNS");
225         }
226     }
227
228     register_for_poll(st, resolver_beforepoll, resolver_afterpoll,
229                       "resolver");
230
231     return new_closure(&st->cl);
232 }
233
234 void resolver_module(dict_t *dict)
235 {
236     add_closure(dict,"adns",adnsresolver_apply);
237 }