- port to Cygwin (DLL support, etc.)

[citadel.git] / citadel / domain.c

diff --git a/citadel/domain.c b/citadel/domain.c
index 3efb74fefb1235cc747a99a927340e7ee9eedf68..ccf62f7c795753d9d09e65f2b7eb035b903eb11d 100644 (file)
--- a/citadel/domain.c
+++ b/citadel/domain.c
@@ -1,11 +1,86 @@
+/*
+ * $Id$
+ *
+ * DNS lookup for SMTP sender
+ *
+ */
+
 #include <stdlib.h>
 #include <unistd.h>
+#include <string.h>
 #include <netinet/in.h>
+#include <stdio.h>
 #include <arpa/nameser.h>
 #include <resolv.h>
+#include "sysdep_decls.h"
+#include "citadel.h"
 #include "domain.h"
+#include "server.h"
+#include "tools.h"
+#include "internet_addressing.h"
+
+
+/*
+ * get_smarthosts() checks the Internet configuration for "smarthost"
+ * entries and returns them in the same format as getmx() does -- fill the
+ * buffer with a delimited list of hosts and return the number of hosts.
+ */
+int get_smarthosts(char *mxbuf) {
+       int config_lines;
+       int i;
+       char buf[SIZ];
+       char host[SIZ], type[SIZ];
+       int total_smarthosts = 0;
+
+       if (inetcfg == NULL) return(0);
+       strcpy(mxbuf, "");
+
+       config_lines = num_tokens(inetcfg, '\n');
+       for (i=0; i<config_lines; ++i) {
+               extract_token(buf, inetcfg, i, '\n');
+               extract_token(host, buf, 0, '|');
+               extract_token(type, buf, 1, '|');
+
+               if (!strcasecmp(type, "smarthost")) {
+                       strcat(mxbuf, host);
+                       strcat(mxbuf, "|");
+                       ++total_smarthosts;
+               }
+       }
+
+       return(total_smarthosts);
+}
+
+
+
+
+/*
+ * sort_mxrecs()
+ *
+ * Sort a pile of MX records (struct mx, definted in domain.h) by preference
+ *
+ */
+void sort_mxrecs(struct mx *mxrecs, int num_mxrecs) {
+       int a, b;
+       struct mx hold1, hold2;
+
+       if (num_mxrecs < 2) return;
+
+       /* do the sort */
+       for (a = num_mxrecs - 2; a >= 0; --a) {
+               for (b = 0; b <= a; ++b) {
+                       if (mxrecs[b].pref > mxrecs[b+1].pref) {
+
+                               memcpy(&hold1, &mxrecs[b], sizeof(struct mx));
+                               memcpy(&hold2, &mxrecs[b+1], sizeof(struct mx));
+                               memcpy(&mxrecs[b], &hold2, sizeof(struct mx));
+                               memcpy(&mxrecs[b+1], &hold1, sizeof(struct mx));
+                       }
+               }
+       }
+}
+
 
-#define SMART_HOST     "gatekeeper.wdcs.com"
 
 /* 
  * getmx()
@@ -20,23 +95,105 @@
 int getmx(char *mxbuf, char *dest) {
        char answer[1024];
        int ret;
-       int i;
-
+       unsigned char *startptr, *endptr, *ptr;
+       char expanded_buf[1024];
+       unsigned short pref, type;
+       int n = 0;
+       HEADER *hp;
+       int qdcount;
 
+       struct mx *mxrecs = NULL;
+       int num_mxrecs = 0;
+       
        /* If we're configured to send all mail to a smart-host, then our
         * job here is really easy.
         */
-       if (1) {        /* FIX */
-               strcpy(mxbuf, SMART_HOST);
-               return(1);
-       }
+       n = get_smarthosts(mxbuf);
+       if (n > 0) return(n);
 
-       /* No smart-host?  Look up the best MX for a site.
+       /*
+        * No smart-host?  Look up the best MX for a site.
         */
        ret = res_query(
                dest,
-               C_IN, T_MX, answer, sizeof(answer)  );
+               C_IN, T_MX, (unsigned char *)answer, sizeof(answer)  );
+
+       if (ret < 0) {
+               mxrecs = mallok(sizeof(struct mx));
+               mxrecs[0].pref = 0;
+               strcpy(mxrecs[0].host, dest);
+               num_mxrecs = 1;
+       }
+       else {
 
-       lprintf(9, "res_query() returned %d\n", ret);
-       return(0); /* FIX not yet working!! */
+               /* If we had to truncate, shrink the number to avoid fireworks */
+               if (ret > sizeof(answer))
+                       ret = sizeof(answer);
+       
+               hp = (HEADER *)&answer[0];
+               startptr = &answer[0];          /* start and end of buffer */
+               endptr = &answer[ret];
+               ptr = startptr + HFIXEDSZ;      /* advance past header */
+       
+               for (qdcount = ntohs(hp->qdcount); qdcount--; ptr += ret + QFIXEDSZ) {
+                       if ((ret = dn_skipname(ptr, endptr)) < 0) {
+                               lprintf(9, "dn_skipname error\n");
+                               return(0);
+                       }
+               }
+       
+               while(1) {
+                       memset(expanded_buf, 0, sizeof(expanded_buf));
+                       ret = dn_expand(startptr,
+                                       endptr,
+                                       ptr,
+                                       expanded_buf,
+                                       sizeof(expanded_buf)
+                                       );
+                       if (ret < 0) break;
+                       ptr += ret;
+       
+                       GETSHORT(type, ptr);
+                       ptr += INT16SZ + INT32SZ;
+                       GETSHORT(n, ptr);
+       
+                       if (type != T_MX) {
+                               ptr += n;
+                       }
+       
+                       else {
+                               GETSHORT(pref, ptr);
+                               ret = dn_expand(startptr,
+                                               endptr,
+                                               ptr,
+                                               expanded_buf,
+                                               sizeof(expanded_buf)
+                                               );
+                               ptr += ret;
+       
+                               ++num_mxrecs;
+                               if (mxrecs == NULL) {
+                                       mxrecs = mallok(sizeof(struct mx));
+                               }
+                               else {
+                                       mxrecs = reallok(mxrecs,
+                                           (sizeof(struct mx) * num_mxrecs) );
+                               }
+       
+                               mxrecs[num_mxrecs - 1].pref = pref;
+                               strcpy(mxrecs[num_mxrecs - 1].host,
+                                      expanded_buf);
+                       }
+               }
+       }
+
+       sort_mxrecs(mxrecs, num_mxrecs);
+
+       strcpy(mxbuf, "");
+       for (n=0; n<num_mxrecs; ++n) {
+               strcat(mxbuf, mxrecs[n].host);
+               strcat(mxbuf, "|");
+       }
+       phree(mxrecs);
+       return(num_mxrecs);
 }