/*
* $Id$
*
- * locate the originating host
+ * Functions which handle hostname/address lookups and resolution
*
*/
-#ifdef DLL_EXPORT
-#define IN_LIBCIT
-#endif
-
#include "sysdep.h"
#include <stdlib.h>
#include <unistd.h>
#include <stdio.h>
+#include <ctype.h>
#include <signal.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
+#include <arpa/inet.h>
#include <limits.h>
#include <netdb.h>
#include <string.h>
+#include <errno.h>
+#include <libcitadel.h>
#include "citadel.h"
#include "server.h"
-#include "dynloader.h"
#include "locate_host.h"
#include "sysdep_decls.h"
#include "config.h"
-#include "tools.h"
+#include "domain.h"
+#include "context.h"
+#include "ctdl_module.h"
+
+#ifdef HAVE_RESOLV_H
+#include <arpa/nameser.h>
+#ifdef HAVE_ARPA_NAMESER_COMPAT_H
+#include <arpa/nameser_compat.h>
+#endif
+#include <resolv.h>
+#endif
-void locate_host(char *tbuf, size_t n, const struct in_addr *addr)
+
+void locate_host(char *tbuf, size_t n, char *abuf, size_t na, int client_socket)
{
- struct hostent *ch;
- const char *i;
- char *j;
- int a1, a2, a3, a4;
+ struct sockaddr_in6 clientaddr;
+ unsigned int addrlen = sizeof(clientaddr);
- lprintf(9, "locate_host() called\n");
+ tbuf[0] = 0;
+ abuf[0] = 0;
-#ifdef HAVE_NONREENTRANT_NETDB
- begin_critical_section(S_NETDB);
-#endif
+ 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);
- if ((ch = gethostbyaddr((const char *) addr, sizeof(*addr), AF_INET)) ==
- NULL) {
- bad_dns:
- i = (const char *) addr;
- a1 = ((*i++) & 0xff);
- a2 = ((*i++) & 0xff);
- a3 = ((*i++) & 0xff);
- a4 = ((*i++) & 0xff);
- snprintf(tbuf, n, "%d.%d.%d.%d", a1, a2, a3, a4);
- goto end; /* because we might need to end the critical
- section */
+ /* Convert IPv6-mapped IPv4 addresses back to traditional dotted quad */
+ if ( (strlen(abuf) > 7) && (!strncasecmp(abuf, "::ffff:", 7)) ) {
+ strcpy(abuf, &abuf[7]);
}
- /* check if the forward DNS agrees; if not, they're spoofing */
- j = strdoop(ch->h_name);
- ch = gethostbyname(j);
- phree(j);
- if (ch == NULL)
- goto bad_dns;
-
- /* check address for consistency */
- for (; *ch->h_addr_list; ch->h_addr_list++)
- if (!memcmp(*ch->h_addr_list, addr,
- sizeof *addr)) {
- safestrncpy(tbuf, ch->h_name, 63);
- goto end;
+}
+
+
+/*
+ * RBL check written by Edward S. Marshall [http://rblcheck.sourceforge.net]
+ */
+#define RESULT_SIZE 4096 /* What is the longest result text we support? */
+int rblcheck_backend(char *domain, char *txtbuf, int txtbufsize) {
+ 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;
+
+ /* Make our DNS query. */
+ //res_init();
+ answer = fixedans;
+ if (CtdlThreadCheckStop())
+ {
+ 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, "");
}
- goto bad_dns; /* they were spoofing. report a numeric IP
- address. */
+ return(0);
+ }
- end:
+ 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 (CtdlThreadCheckStop())
+ {
+ if (txtbuf != NULL)
+ snprintf(txtbuf, txtbufsize, "System shutting down");
+ if (need_to_free_answer) free(answer);
+ return (1);
+ }
-#ifdef HAVE_NONREENTRANT_NETDB
- end_critical_section(S_NETDB);
-#endif
+ 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. */
+ res_init();
+ len = res_query( domain, C_IN, T_TXT, answer, PACKETSZ );
+ if (CtdlThreadCheckStop())
+ {
+ 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) {
+ snprintf(txtbuf, txtbufsize, "%s", result);
+ }
+ /* Remove nonprintable characters */
+ for (p=txtbuf; *p; ++p) {
+ if (!isprint(*p)) strcpy(p, p+1);
+ }
+ if (need_to_free_answer) free(answer);
+ free(result);
+ return(1);
+}
+
+
+/*
+ * Check to see if a host is on some sort of spam list (RBL)
+ * If spammer, returns nonzero and places reason in 'message_to_spammer'
+ */
+int rbl_check_addr(struct in_addr *addr, char *message_to_spammer)
+{
+ int a1, a2, a3, a4;
+ char tbuf[256];
+ int rbl;
+ int num_rbl;
+ char rbl_domains[SIZ];
+ char txt_answer[1024];
+ char dotted_quad[32];
+
+ strcpy(message_to_spammer, "ok");
+ safestrncpy(dotted_quad, inet_ntoa(*addr), sizeof dotted_quad);
+ sscanf(dotted_quad, "%d.%d.%d.%d", &a1, &a2, &a3, &a4);
+
+ /* 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) {
+ snprintf(tbuf, sizeof tbuf,
+ "%d.%d.%d.%d.",
+ a4, a3, a2, a1);
+ extract_token(&tbuf[strlen(tbuf)], rbl_domains, rbl, '|', (sizeof tbuf - strlen(tbuf)));
+
+ if (rblcheck_backend(tbuf, txt_answer, sizeof txt_answer)) {
+ strcpy(message_to_spammer, txt_answer);
+ CtdlLogPrintf(CTDL_INFO, "RBL: %s\n", txt_answer);
+ return(1);
+ }
+ }
+
+ return(0);
+}
+
+
+/*
+ * Check to see if the client host is on some sort of spam list (RBL)
+ * If spammer, returns nonzero and places reason in 'message_to_spammer'
+ *
+ * PORTABILITY NOTE! I've made my best effort to rewrite this in a portable fashion.
+ * If anyone makes changes to this function, please shout-out so we can test it to
+ * make sure it didn't break on Linux!
+ */
+int rbl_check(char *message_to_spammer) {
+ int r;
+ struct sockaddr_in peer;
+ socklen_t peer_len = 0;
+
+ peer_len = sizeof(peer);
+ r = getpeername(CC->client_socket, &peer, &peer_len);
+ if (r == 0) {
+ return(rbl_check_addr(&peer.sin_addr, message_to_spammer));
+ }
+ else {
+ CtdlLogPrintf(CTDL_INFO, "RBL getpeername() failed: %s\n", strerror(errno));
+ }
+ return(0);
+}
+
+/*
+ * Convert a host name to a dotted quad address.
+ * Returns zero on success or nonzero on failure.
+ */
+int hostname_to_dotted_quad(char *addr, char *host) {
+ 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);
+ }
- tbuf[63] = 0;
- lprintf(9, "locate_host() exiting\n");
+ 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);
}
projects / citadel.git / blobdiff