Added rfc1035BuildPTRQuery()

Changed rfc1035AnswersUnpack() to unpack DNS names into character
buffers so that the upper layers don't have to.   This is the switch
statement inside that function that exectues different copies
based on the record type.

diff --git a/lib/rfc1035.c b/lib/rfc1035.c
index 759a003757f2b9bbcc84ece0bdf00dd163e70ecc..00f3b748dcf396ba865a4755673949da1b6d8b07 100644 (file)
--- a/lib/rfc1035.c
+++ b/lib/rfc1035.c
@@ -1,5 +1,5 @@
 /*
- * $Id: rfc1035.c,v 1.4 1999/04/14 06:38:03 wessels Exp $
+ * $Id: rfc1035.c,v 1.5 1999/04/18 05:10:07 wessels Exp $
  *
  * Low level DNS protocol routines
  * AUTHOR: Duane Wessels
@@ -319,9 +319,19 @@ rfc1035RRUnpack(const char *buf, size_t sz, off_t off, rfc1035_rr * RR)
     RR->ttl = ntohl(i);
     memcpy(&s, buf + off, sizeof(s));
     off += sizeof(s);
-    RR->rdlength = ntohs(s);
-    RR->rdata = malloc(RR->rdlength);
-    memcpy(RR->rdata, buf + off, RR->rdlength);
+    switch (RR->type) {
+    case RFC1035_TYPE_PTR:
+       RR->rdata = malloc(RFC1035_MAXHOSTNAMESZ);
+       rfc1035NameUnpack(buf, sz, off, RR->rdata, RFC1035_MAXHOSTNAMESZ);
+       RR->rdlength = strlen(RR->rdata);
+       break;
+    case RFC1035_TYPE_A:
+    default:
+       RR->rdlength = ntohs(s);
+       RR->rdata = malloc(RR->rdlength);
+       memcpy(RR->rdata, buf + off, RR->rdlength);
+       break;
+    }
     off += RR->rdlength;
     assert(off <= sz);
     return off;
@@ -428,7 +438,7 @@ rfc1035AnswersUnpack(const char *buf,
 }
 
 /*
- * rfc1035BuildQuery()
+ * rfc1035BuildAQuery()
  * 
  * Builds a message buffer with a QUESTION to lookup A records
  * for a hostname.  Caller must allocate 'buf' which should
@@ -460,17 +470,59 @@ rfc1035BuildAQuery(const char *hostname, char *buf, size_t * szp)
     return h.id;
 }
 
+/*
+ * rfc1035BuildPTRQuery()
+ * 
+ * Builds a message buffer with a QUESTION to lookup PTR records
+ * for an address.  Caller must allocate 'buf' which should
+ * probably be at least 512 octets.  The 'szp' initially
+ * specifies the size of the buffer, on return it contains
+ * the size of the message (i.e. how much to write).
+ * Return value is the query ID.
+ */
+unsigned short
+rfc1035BuildPTRQuery(const struct in_addr addr, char *buf, size_t * szp)
+{
+    static rfc1035_header h;
+    off_t offset = 0;
+    size_t sz = *szp;
+    static char rev[32];
+    unsigned int i;
+    memset(&h, '\0', sizeof(h));
+    i = (unsigned int) addr.s_addr;
+    snprintf(rev, 32, "%u.%u.%u.%u.in-addr.arpa",
+       (i >> 24) & 255,
+       (i >> 16) & 255,
+       (i >> 8) & 255,
+       i & 255);
+    printf("rfc1035BuildPTRQuery: {%s}\n", rev);
+    h.id = rfc1035Qid();
+    h.qr = 0;
+    h.rd = 1;
+    h.opcode = 0;              /* QUERY */
+    h.qdcount = (unsigned int) 1;
+    offset += rfc1035HeaderPack(buf + offset, sz - offset, &h);
+    offset += rfc1035QuestionPack(buf + offset,
+       sz - offset,
+       rev,
+       RFC1035_TYPE_PTR,
+       RFC1035_CLASS_IN);
+    assert(offset <= sz);
+    *szp = (size_t) offset;
+    return h.id;
+}
+
 #if DRIVER
+#include <sys/socket.h>
+#include <sys/time.h>
 int
 main(int argc, char *argv[])
 {
-    rfc1035_header h;
     char input[512];
     char buf[512];
     char rbuf[512];
     size_t sz = 512;
     unsigned short sid;
-    off_t offset = 0;
     int s;
     int rl;
     struct sockaddr_in S;
@@ -482,26 +534,20 @@ main(int argc, char *argv[])
        return 1;
     }
     while (fgets(input, 512, stdin)) {
+       struct in_addr junk;
        strtok(input, "\r\n");
        memset(buf, '\0', 512);
-       memset(&h, '\0', sizeof(h));
-       offset = 0;
-       h.id = sid = (unsigned short) 0x1234;
-       h.qr = 0;
-       h.rd = 1;
-       h.opcode = 0;
-       h.qdcount = (unsigned int) 1;
-       offset += rfc1035HeaderPack(buf + offset, sz - offset, &h);
-       offset += rfc1035QuestionPack(buf + offset,
-           sz - offset,
-           input,
-           RFC1035_TYPE_A,
-           RFC1035_CLASS_IN);
+       sz = 512;
+       if (inet_aton(input, &junk)) {
+           sid = rfc1035BuildPTRQuery(junk, buf, &sz);
+       } else {
+           sid = rfc1035BuildAQuery(input, buf, &sz);
+       }
        memset(&S, '\0', sizeof(S));
        S.sin_family = AF_INET;
        S.sin_port = htons(53);
        S.sin_addr.s_addr = inet_addr("128.117.28.219");
-       sendto(s, buf, (size_t) offset, 0, (struct sockaddr *) &S, sizeof(S));
+       sendto(s, buf, sz, 0, (struct sockaddr *) &S, sizeof(S));
        do {
            fd_set R;
            struct timeval to;
@@ -521,24 +567,31 @@ main(int argc, char *argv[])
            unsigned short rid;
            int i;
            int n;
-           struct in_addr addrs[10];
-           time_t ttl = 0;
-           char rname[RFC1035_MAXHOSTNAMESZ];
-           n = rfc1035ARecordsUnpack(rbuf,
+           rfc1035_rr *answers = NULL;
+           n = rfc1035AnswersUnpack(rbuf,
                rl,
-               addrs, 10,
-               rname, RFC1035_MAXHOSTNAMESZ,
-               &rid,
-               &ttl);
+               &answers,
+               &rid);
            if (rid != sid) {
                printf("ERROR, ID mismatch (%#hx, %#hx)\n", sid, rid);
            } else if (n < 0) {
                printf("ERROR %d\n", rfc1035_errno);
            } else {
-               printf("name\t%s, %d A records\n", rname, n);
-               printf("ttl\t%d\n", (int) ttl);
-               for (i = 0; i < n; i++)
-                   printf("addr %d\t%s\n", i, inet_ntoa(addrs[i]));
+               printf("%d answers\n", n);
+               for (i = 0; i < n; i++) {
+                   if (answers[i].type == RFC1035_TYPE_A) {
+                       struct in_addr a;
+                       memcpy(&a, answers[i].rdata, 4);
+                       printf("A\t%d\t%s\n", answers[i].ttl, inet_ntoa(a));
+                   } else if (answers[i].type == RFC1035_TYPE_PTR) {
+                       char ptr[128];
+                       strncpy(ptr, answers[i].rdata, answers[i].rdlength);
+                       printf("PTR\t%d\t%s\n", answers[i].ttl, ptr);
+                   } else {
+                       fprintf(stderr, "can't print answer type %d\n",
+                           (int) answers[i].type);
+                   }
+               }
            }
        }
     }