| 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 | if (conf) { |
| 214 | if (adns_init_strcfg(&st->ast, 0, 0, conf)) { |
| 215 | fatal_perror("Failed to initialise ADNS"); |
| 216 | } |
| 217 | } else { |
| 218 | if (adns_init(&st->ast, 0, 0)) { |
| 219 | fatal_perror("Failed to initialise ADNS"); |
| 220 | } |
| 221 | } |
| 222 | |
| 223 | register_for_poll(st, resolver_beforepoll, resolver_afterpoll, |
| 224 | "resolver"); |
| 225 | |
| 226 | return new_closure(&st->cl); |
| 227 | } |
| 228 | |
| 229 | void resolver_module(dict_t *dict) |
| 230 | { |
| 231 | add_closure(dict,"adns",adnsresolver_apply); |
| 232 | } |