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citadel  8.12
Functions
locate_host.h File Reference
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Functions

void locate_host (char *tbuf, size_t n, char *abuf, size_t na, int client_socket)
 END:some missing macros on OpenBSD 3.9.
int rbl_check (char *message_to_spammer)
int hostname_to_dotted_quad (char *addr, char *host)
int rblcheck_backend (char *domain, char *txtbuf, int txtbufsize)

Function Documentation

int hostname_to_dotted_quad ( char *  addr,
char *  host 
)

Definition at line 349 of file locate_host.c.

                                                    {
       struct hostent *ch;
       const char *i;
       int a1, a2, a3, a4;

       ch = gethostbyname(host);
       if (ch == NULL) {
              strcpy(addr, "0.0.0.0");
              return(1);
       }

       i = (const char *) ch->h_addr_list[0];
       a1 = ((*i++) & 0xff);
       a2 = ((*i++) & 0xff);
       a3 = ((*i++) & 0xff);
       a4 = ((*i++) & 0xff);
       sprintf(addr, "%d.%d.%d.%d", a1, a2, a3, a4);
       return(0);
}

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void locate_host ( char *  tbuf,
size_t  n,
char *  abuf,
size_t  na,
int  client_socket 
)

END:some missing macros on OpenBSD 3.9.

Definition at line 75 of file locate_host.c.

{
       struct sockaddr_in6 clientaddr;
       unsigned int addrlen = sizeof(clientaddr);

       tbuf[0] = 0;
       abuf[0] = 0;

       getpeername(client_socket, (struct sockaddr *)&clientaddr, &addrlen);
       getnameinfo((struct sockaddr *)&clientaddr, addrlen, tbuf, n, NULL, 0, 0);
       getnameinfo((struct sockaddr *)&clientaddr, addrlen, abuf, na, NULL, 0, NI_NUMERICHOST);

       /* Convert IPv6-mapped IPv4 addresses back to traditional dotted quad.
        *
        * Other code here, such as the RBL check, will expect IPv4 addresses to be represented
        * as dotted-quad, even if they come in over a hybrid IPv6/IPv4 socket.
        */
       if ( (strlen(abuf) > 7) && (!strncasecmp(abuf, "::ffff:", 7)) ) {
              if (!strcmp(abuf, tbuf)) strcpy(tbuf, &tbuf[7]);
              strcpy(abuf, &abuf[7]);
       }
}

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int rbl_check ( char *  message_to_spammer)

Definition at line 260 of file locate_host.c.

{
       char tbuf[256] = "";
       int suffix_pos = 0;
       int rbl;
       int num_rbl;
       char rbl_domains[SIZ];
       char txt_answer[1024];

       strcpy(message_to_spammer, "ok");

       if ((strchr(CC->cs_addr, '.')) && (!strchr(CC->cs_addr, ':'))) {
              int a1, a2, a3, a4;

              sscanf(CC->cs_addr, "%d.%d.%d.%d", &a1, &a2, &a3, &a4);
              snprintf(tbuf, sizeof tbuf, "%d.%d.%d.%d.", a4, a3, a2, a1);
              suffix_pos = strlen(tbuf);
       }
       else if ((!strchr(CC->cs_addr, '.')) && (strchr(CC->cs_addr, ':'))) {
              int num_colons = 0;
              int i = 0;
              char workbuf[sizeof tbuf];
              char *ptr;

              /* tedious code to expand and reverse an IPv6 address */
              safestrncpy(tbuf, CC->cs_addr, sizeof tbuf);
              num_colons = haschar(tbuf, ':');
              if ((num_colons < 2) || (num_colons > 7)) return(0);    /* badly formed address */

              /* expand the "::" shorthand */
              while (num_colons < 7) {
                     ptr = strstr(tbuf, "::");
                     if (!ptr) return(0);                      /* badly formed address */
                     ++ptr;
                     strcpy(workbuf, ptr);
                     strcpy(ptr, ":");
                     strcat(ptr, workbuf);
                     ++num_colons;
              }

              /* expand to 32 hex characters with no colons */
              strcpy(workbuf, tbuf);
              strcpy(tbuf, "00000000000000000000000000000000");
              for (i=0; i<8; ++i) {
                     char tokbuf[5];
                     extract_token(tokbuf, workbuf, i, ':', sizeof tokbuf);

                     memcpy(&tbuf[ (i*4) + (4-strlen(tokbuf)) ], tokbuf, strlen(tokbuf) );
              }
              if (strlen(tbuf) != 32) return(0);

              /* now reverse it and add dots */
              strcpy(workbuf, tbuf);
              for (i=0; i<32; ++i) {
                     tbuf[i*2] = workbuf[31-i];
                     tbuf[(i*2)+1] = '.';
              }
              tbuf[64] = 0;
              suffix_pos = 64;
       }
       else {
              return(0);    /* unknown address format */
       }

       /* See if we have any RBL domains configured */
       num_rbl = get_hosts(rbl_domains, "rbl");
       if (num_rbl < 1) return(0);

       /* Try all configured RBL's */
        for (rbl=0; rbl<num_rbl; ++rbl) {
                extract_token(&tbuf[suffix_pos], rbl_domains, rbl, '|', (sizeof tbuf - suffix_pos));

              if (rblcheck_backend(tbuf, txt_answer, sizeof txt_answer)) {
                     strcpy(message_to_spammer, txt_answer);
                     syslog(LOG_INFO, "RBL: %s\n", txt_answer);
                     return(1);
              }
       }

       return(0);
}

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int rblcheck_backend ( char *  domain,
char *  txtbuf,
int  txtbufsize 
)

Definition at line 103 of file locate_host.c.

                                                                 {
       int a, b, c;
       char *result = NULL;
       u_char fixedans[ PACKETSZ ];
       u_char *answer;
       int need_to_free_answer = 0;
       const u_char *cp;
       u_char *rp;
       const u_char *cend;
       const u_char *rend;
       int len;
       char *p = NULL;
       static int res_initted = 0;

       if (!res_initted) {         /* only have to do this once */
              res_init();
              res_initted = 1;
       }

       /* Make our DNS query. */
       answer = fixedans;
       if (server_shutting_down)
       {
              if (txtbuf != NULL) {
                     snprintf(txtbuf, txtbufsize, "System shutting down");
              }
              return (1);
       }
       len = res_query(domain, C_IN, T_A, answer, PACKETSZ);

       /* Was there a problem? If so, the domain doesn't exist. */
       if (len == -1) {
              if (txtbuf != NULL) {
                     strcpy(txtbuf, "");
              }
              return(0);
       }

       if( len > PACKETSZ )
       {
              answer = malloc(len);
              need_to_free_answer = 1;
              len = res_query(domain, C_IN, T_A, answer, len);
              if( len == -1 ) {
                     if (txtbuf != NULL) {
                            snprintf(txtbuf, txtbufsize,
                                    "Message rejected due to known spammer source IP address");
                     }
                     if (need_to_free_answer) free(answer);
                     return(1);
              }
       }
       if (server_shutting_down)
       {
              if (txtbuf != NULL)
                     snprintf(txtbuf, txtbufsize, "System shutting down");
              if (need_to_free_answer) free(answer);
              return (1);
       }

       result = (char *) malloc(RESULT_SIZE);
       result[ 0 ] = '\0';


       /* Make another DNS query for textual data; this shouldn't
        * be a performance hit, since it'll now be cached at the
        * nameserver we're using.
        */
       len = res_query(domain, C_IN, T_TXT, answer, PACKETSZ);
       if (server_shutting_down)
       {
              if (txtbuf != NULL) {
                     snprintf(txtbuf, txtbufsize, "System shutting down");
              }
              if (need_to_free_answer) free(answer);
              free(result);
              return (1);
       }

       /* Just in case there's no TXT record... */
       if (len ==(-1))
       {
              if (txtbuf != NULL) {
                     snprintf(txtbuf, txtbufsize,
                             "Message rejected due to known spammer source IP address");
              }
              if (need_to_free_answer) free(answer);
              free(result);
              return(1);
       }

       /* Skip the header and the address we queried. */
       cp = answer + sizeof( HEADER );
       while( *cp != '\0' )
       {
              a = *cp++;
              while( a-- )
                     cp++;
       }

       /* This seems to be a bit of magic data that we need to
        * skip. I wish there were good online documentation
        * for programming for libresolv, so I'd know what I'm
        * skipping here. Anyone reading this, feel free to
        * enlighten me.
        */
       cp += 1 + NS_INT16SZ + NS_INT32SZ;

       /* Skip the type, class and ttl. */
       cp += (NS_INT16SZ * 2) + NS_INT32SZ;

       /* Get the length and end of the buffer. */
       NS_GET16(c, cp);
       cend = cp + c;

       /* Iterate over any multiple answers we might have. In
        * this context, it's unlikely, but anyway.
        */
       rp = (u_char *) result;
       rend = (u_char *) result + RESULT_SIZE - 1;
       while (cp < cend && rp < rend)
       {
              a = *cp++;
              if( a != 0 )
                     for (b = a; b > 0 && cp < cend && rp < rend; b--)
                     {
                            if (*cp == '\n' || *cp == '"' || *cp == '\\')
                            {
                                   *rp++ = '\\';
                            }
                            *rp++ = *cp++;
                     }
       }
       *rp = '\0';
       if (txtbuf != NULL) {
              long len;
              len = snprintf(txtbuf, txtbufsize, "%s", result);
       
              /* Remove nonprintable characters */
              for (p = txtbuf; *p != '\0'; p++) {
                     if (!isprint(*p)) {
                            memmove (p,
                                    p + 1,
                                    len - (p - txtbuf) - 1);
                     }
              }
       }
       if (need_to_free_answer) free(answer);
       free(result);
       return(1);
}

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