Debug: internal consistency under testsuite
[exim.git] / src / src / routers / rf_lookup_hostlist.c
1 /*************************************************
2 * Exim - an Internet mail transport agent *
3 *************************************************/
4
5 /* Copyright (c) University of Cambridge 1995 - 2015 */
6 /* See the file NOTICE for conditions of use and distribution. */
7
8
9 #include "../exim.h"
10 #include "rf_functions.h"
11
12
13
14 /*************************************************
15 * Look up IP addresses for a set of hosts *
16 *************************************************/
17
18 /* This function is called by a router to fill in the IP addresses for a set of
19 hosts that are attached to an address. Each host has its name and MX value set;
20 and those that need processing have their address fields set NULL. Multihomed
21 hosts cause additional blocks to be inserted into the chain.
22
23 This function also supports pseudo-hosts whose names end with "/MX". In this
24 case, MX records are looked up for the name, and the list of hosts obtained
25 replaces the incoming "host". In other words, "x/MX" is shorthand for "those
26 hosts pointed to by x's MX records".
27
28 It is also possible for a port to be specified along with the host name or IP
29 address. The syntax is to add ":port" on to the end. This doesn't work with
30 IPv6 addresses, so we allow IP addresses to be enclosed in [] in order to make
31 this work. The specification of the port must come last, that is, after "/MX"
32 if that is present.
33
34 Arguments:
35 rblock the router block
36 addr the address being routed
37 ignore_target_hosts list of hosts to ignore
38 lookup_type LK_DEFAULT or LK_BYNAME or LK_BYDNS,
39 plus LK_IPV4_{ONLY,PREFER}
40 hff_code what to do for host find failed
41 addr_new passed to rf_self_action for self=reroute
42
43 Returns: OK
44 DEFER host lookup defer
45 PASS timeout etc and pass_on_timeout set
46 self_action: PASS, DECLINE, DEFER, FAIL, FREEZE
47 hff_code after host find failed
48 */
49
50 int
51 rf_lookup_hostlist(router_instance *rblock, address_item *addr,
52 uschar *ignore_target_hosts, int lookup_type, int hff_code,
53 address_item **addr_new)
54 {
55 BOOL self_send = FALSE;
56
57 /* Look up each host address. A lookup may add additional items into the chain
58 if there are multiple addresses. Hence the use of next_h to start each cycle of
59 the loop at the next original host. If any host is identified as being the local
60 host, omit it and any subsequent hosts - i.e. treat the list like an ordered
61 list of MX hosts. If the first host is the local host, act according to the
62 "self" option in the configuration. */
63
64 for (host_item * prev = NULL, * h = addr->host_list, *next_h; h; h = next_h)
65 {
66 const uschar *canonical_name;
67 int rc, len, port, mx, sort_key;
68
69 next_h = h->next;
70 if (h->address) { prev = h; continue; }
71
72 DEBUG(D_route|D_host_lookup)
73 debug_printf("finding IP address for %s\n", h->name);
74
75 /* Handle any port setting that may be on the name; it will be removed
76 from the end of the name. */
77
78 port = host_item_get_port(h);
79
80 /* Store the previous mx and sort_key values, which were assigned in
81 host_build_hostlist and will be overwritten by host_find_bydns. */
82
83 mx = h->mx;
84 sort_key = h->sort_key;
85
86 /* If the name ends with "/MX", we interpret it to mean "the list of hosts
87 pointed to by MX records with this name", and the MX record values override
88 the ordering from host_build_hostlist. */
89
90 len = Ustrlen(h->name);
91 if (len > 3 && strcmpic(h->name + len - 3, US"/mx") == 0)
92 {
93 int whichrrs = lookup_type & LK_IPV4_ONLY
94 ? HOST_FIND_BY_MX | HOST_FIND_IPV4_ONLY
95 : lookup_type & LK_IPV4_PREFER
96 ? HOST_FIND_BY_MX | HOST_FIND_IPV4_FIRST
97 : HOST_FIND_BY_MX;
98
99 DEBUG(D_route|D_host_lookup)
100 debug_printf("doing DNS MX lookup for %s\n", h->name);
101
102 mx = MX_NONE;
103 h->name = string_copyn(h->name, len - 3);
104 rc = host_find_bydns(h,
105 ignore_target_hosts,
106 whichrrs, /* look only for MX records */
107 NULL, /* SRV service not relevant */
108 NULL, /* failing srv domains not relevant */
109 NULL, /* no special mx failing domains */
110 &rblock->dnssec, /* dnssec request/require */
111 NULL, /* fully_qualified_name */
112 NULL); /* indicate local host removed */
113 }
114
115 /* If explicitly configured to look up by name, or if the "host name" is
116 actually an IP address, do a byname lookup. */
117
118 else if (lookup_type & LK_BYNAME || string_is_ip_address(h->name, NULL) != 0)
119 {
120 DEBUG(D_route|D_host_lookup) debug_printf("calling host_find_byname\n");
121 rc = host_find_byname(h, ignore_target_hosts, HOST_FIND_QUALIFY_SINGLE,
122 &canonical_name, TRUE);
123 }
124
125 /* Otherwise, do a DNS lookup. If that yields "host not found", and the
126 lookup type is the default (i.e. "bydns" is not explicitly configured),
127 follow up with a byname lookup, just in case. */
128
129 else
130 {
131 BOOL removed;
132 int whichrrs = lookup_type & LK_IPV4_ONLY
133 ? HOST_FIND_BY_A
134 : lookup_type & LK_IPV4_PREFER
135 ? HOST_FIND_BY_A | HOST_FIND_BY_AAAA | HOST_FIND_IPV4_FIRST
136 : HOST_FIND_BY_A | HOST_FIND_BY_AAAA;
137
138 DEBUG(D_route|D_host_lookup) debug_printf("doing DNS lookup\n");
139 switch (rc = host_find_bydns(h, ignore_target_hosts, whichrrs, NULL,
140 NULL, NULL,
141 &rblock->dnssec, /* domains for request/require */
142 &canonical_name, &removed))
143 {
144 case HOST_FOUND:
145 if (removed) setflag(addr, af_local_host_removed);
146 break;
147 case HOST_FIND_FAILED:
148 if (lookup_type & LK_DEFAULT)
149 {
150 DEBUG(D_route|D_host_lookup)
151 debug_printf("DNS lookup failed: trying %s\n",
152 f.running_in_test_harness
153 ? "host_fake_gethostbyname" : "getipnodebyname");
154 rc = host_find_byname(h, ignore_target_hosts, HOST_FIND_QUALIFY_SINGLE,
155 &canonical_name, TRUE);
156 }
157 break;
158 }
159 }
160
161 /* Temporary failure defers, unless pass_on_timeout is set */
162
163 if (rc == HOST_FIND_SECURITY)
164 {
165 addr->message = string_sprintf("host lookup for %s done insecurely" , h->name);
166 addr->basic_errno = ERRNO_DNSDEFER;
167 return DEFER;
168 }
169 if (rc == HOST_FIND_AGAIN)
170 {
171 if (rblock->pass_on_timeout)
172 {
173 DEBUG(D_route)
174 debug_printf("%s router timed out and pass_on_timeout set\n",
175 rblock->name);
176 return PASS;
177 }
178 addr->message = string_sprintf("host lookup for %s did not complete "
179 "(DNS timeout?)", h->name);
180 addr->basic_errno = ERRNO_DNSDEFER;
181 return DEFER;
182 }
183
184 /* Permanent failure is controlled by host_find_failed */
185
186 if (rc == HOST_FIND_FAILED)
187 {
188 if (hff_code == hff_ignore)
189 {
190 if (prev == NULL) addr->host_list = next_h; else prev->next = next_h;
191 continue; /* With the next host, leave prev unchanged */
192 }
193
194 if (hff_code == hff_pass) return PASS;
195 if (hff_code == hff_decline) return DECLINE;
196
197 addr->basic_errno = ERRNO_UNKNOWNHOST;
198 addr->message =
199 string_sprintf("lookup of host \"%s\" failed in %s router%s",
200 h->name, rblock->name,
201 f.host_find_failed_syntax? ": syntax error in name" : "");
202
203 if (hff_code == hff_defer) return DEFER;
204 if (hff_code == hff_fail) return FAIL;
205
206 addr->special_action = SPECIAL_FREEZE;
207 return DEFER;
208 }
209
210 /* Deal with the settings that were previously cleared:
211 port, mx and sort_key. */
212
213 if (port != PORT_NONE)
214 for (host_item * hh = h; hh != next_h; hh = hh->next)
215 hh->port = port;
216
217 if (mx != MX_NONE)
218 for (host_item * hh = h; hh != next_h; hh = hh->next)
219 {
220 hh->mx = mx;
221 hh->sort_key = sort_key;
222 }
223
224 /* A local host gets chopped, with its successors, if there are previous
225 hosts. Otherwise the self option is used. If it is set to "send", any
226 subsequent hosts that are also the local host do NOT get chopped. */
227
228 if (rc == HOST_FOUND_LOCAL && !self_send)
229 {
230 if (prev)
231 {
232 DEBUG(D_route)
233 {
234 debug_printf("Removed from host list:\n");
235 for (; h; h = h->next) debug_printf(" %s\n", h->name);
236 }
237 prev->next = NULL;
238 setflag(addr, af_local_host_removed);
239 break;
240 }
241 rc = rf_self_action(addr, h, rblock->self_code, rblock->self_rewrite,
242 rblock->self, addr_new);
243 if (rc != OK)
244 {
245 addr->host_list = NULL; /* Kill the host list for */
246 return rc; /* anything other than "send" */
247 }
248 self_send = TRUE;
249 }
250
251 /* Ensure that prev is the host before next_h; this will not be h if a lookup
252 found multiple addresses or multiple MX records. */
253
254 prev = h;
255 while (prev->next != next_h) prev = prev->next;
256 }
257
258 return OK;
259 }
260
261 /* End of rf_lookup_hostlist.c */