1 files changed, 315 insertions, 0 deletions

diff --git a/src/util/dict_tcp.c b/src/util/dict_tcp.c
new file mode 100644
index 0000000..922f449
--- /dev/null
+++ b/src/util/dict_tcp.c
@@ -0,0 +1,315 @@
+/*++
+/* NAME
+/*	dict_tcp 3
+/* SUMMARY
+/*	dictionary manager interface to tcp-based lookup tables
+/* SYNOPSIS
+/*	#include <dict_tcp.h>
+/*
+/*	DICT	*dict_tcp_open(map, open_flags, dict_flags)
+/*	const char *map;
+/*	int	open_flags;
+/*	int	dict_flags;
+/* DESCRIPTION
+/*	dict_tcp_open() makes a TCP server accessible via the generic
+/*	dictionary operations described in dict_open(3).
+/*	The only implemented operation is dictionary lookup. This map
+/*	type can be useful for simulating a dynamic lookup table.
+/*
+/*	Map names have the form host:port.
+/*
+/*	The TCP map class implements a very simple protocol: the client
+/*	sends a request, and the server sends one reply. Requests and
+/*	replies are sent as one line of ASCII text, terminated by the
+/*	ASCII newline character. Request and reply parameters (see below)
+/*	are separated by whitespace.
+/* ENCODING
+/* .ad
+/* .fi
+/*	In request and reply parameters, the character % and any non-printing
+/*	and whitespace characters must be replaced by %XX, XX being the
+/*	corresponding ASCII hexadecimal character value. The hexadecimal codes
+/*	can be specified in any case (upper, lower, mixed).
+/* REQUEST FORMAT
+/* .ad
+/* .fi
+/*	Requests are strings that serve as lookup key in the simulated
+/*	table.
+/* .IP "get SPACE key NEWLINE"
+/*	Look up data under the specified key.
+/* .IP "put SPACE key SPACE value NEWLINE"
+/*	This request is currently not implemented.
+/* REPLY FORMAT
+/* .ad
+/* .fi
+/*	Replies must be no longer than 4096 characters including the
+/*	newline terminator, and must have the following form:
+/* .IP "500 SPACE text NEWLINE"
+/*	In case of a lookup request, the requested data does not exist.
+/*	In case of an update request, the request was rejected.
+/*	The text gives the nature of the problem.
+/* .IP "400 SPACE text NEWLINE"
+/*	This indicates an error condition. The text gives the nature of
+/*	the problem. The client should retry the request later.
+/* .IP "200 SPACE text NEWLINE"
+/*	The request was successful. In the case of a lookup request,
+/*	the text contains an encoded version of the requested data.
+/* SECURITY
+/*	This map must not be used for security sensitive information,
+/*	because neither the connection nor the server are authenticated.
+/* SEE ALSO
+/*	dict(3) generic dictionary manager
+/*	hex_quote(3) http-style quoting
+/* DIAGNOSTICS
+/*	Fatal errors: out of memory, unknown host or service name,
+/*	attempt to update or iterate over map.
+/* BUGS
+/*	Only the lookup method is currently implemented.
+/* LICENSE
+/* .ad
+/* .fi
+/*	The Secure Mailer license must be distributed with this software.
+/* AUTHOR(S)
+/*	Wietse Venema
+/*	IBM T.J. Watson Research
+/*	P.O. Box 704
+/*	Yorktown Heights, NY 10598, USA
+/*--*/
+
+/* System library. */
+
+#include "sys_defs.h"
+#include <unistd.h>
+#include <string.h>
+#include <errno.h>
+#include <ctype.h>
+
+/* Utility library. */
+
+#include <msg.h>
+#include <mymalloc.h>
+#include <vstring.h>
+#include <vstream.h>
+#include <vstring_vstream.h>
+#include <connect.h>
+#include <hex_quote.h>
+#include <dict.h>
+#include <stringops.h>
+#include <dict_tcp.h>
+
+/* Application-specific. */
+
+typedef struct {
+    DICT    dict;			/* generic members */
+    VSTRING *raw_buf;			/* raw I/O buffer */
+    VSTRING *hex_buf;			/* quoted I/O buffer */
+    VSTREAM *fp;			/* I/O stream */
+} DICT_TCP;
+
+#define DICT_TCP_MAXTRY	10		/* attempts before giving up */
+#define DICT_TCP_TMOUT	100		/* connect/read/write timeout */
+#define DICT_TCP_MAXLEN	4096		/* server reply size limit */
+
+#define STR(x)		vstring_str(x)
+
+/* dict_tcp_connect - connect to TCP server */
+
+static int dict_tcp_connect(DICT_TCP *dict_tcp)
+{
+    int     fd;
+
+    /*
+     * Connect to the server. Enforce a time limit on all operations so that
+     * we do not get stuck.
+     */
+    if ((fd = inet_connect(dict_tcp->dict.name, NON_BLOCKING, DICT_TCP_TMOUT)) < 0) {
+	msg_warn("connect to TCP map %s: %m", dict_tcp->dict.name);
+	return (-1);
+    }
+    dict_tcp->fp = vstream_fdopen(fd, O_RDWR);
+    vstream_control(dict_tcp->fp,
+		    CA_VSTREAM_CTL_TIMEOUT(DICT_TCP_TMOUT),
+		    CA_VSTREAM_CTL_END);
+
+    /*
+     * Allocate per-map I/O buffers on the fly.
+     */
+    if (dict_tcp->raw_buf == 0) {
+	dict_tcp->raw_buf = vstring_alloc(10);
+	dict_tcp->hex_buf = vstring_alloc(10);
+    }
+    return (0);
+}
+
+/* dict_tcp_disconnect - disconnect from TCP server */
+
+static void dict_tcp_disconnect(DICT_TCP *dict_tcp)
+{
+    (void) vstream_fclose(dict_tcp->fp);
+    dict_tcp->fp = 0;
+}
+
+/* dict_tcp_lookup - request TCP server */
+
+static const char *dict_tcp_lookup(DICT *dict, const char *key)
+{
+    DICT_TCP *dict_tcp = (DICT_TCP *) dict;
+    const char *myname = "dict_tcp_lookup";
+    int     tries;
+    char   *start;
+    int     last_ch;
+
+#define RETURN(errval, result) { dict->error = errval; return (result); }
+
+    if (msg_verbose)
+	msg_info("%s: key %s", myname, key);
+
+    /*
+     * Optionally fold the key.
+     */
+    if (dict->flags & DICT_FLAG_FOLD_MUL) {
+	if (dict->fold_buf == 0)
+	    dict->fold_buf = vstring_alloc(10);
+	vstring_strcpy(dict->fold_buf, key);
+	key = lowercase(vstring_str(dict->fold_buf));
+    }
+    for (tries = 0; /* see below */ ; /* see below */ ) {
+
+	/*
+	 * Connect to the server, or use an existing connection.
+	 */
+	if (dict_tcp->fp != 0 || dict_tcp_connect(dict_tcp) == 0) {
+
+	    /*
+	     * Send request and receive response. Both are %XX quoted and
+	     * both are terminated by newline. This encoding is convenient
+	     * for data that is mostly text.
+	     */
+	    hex_quote(dict_tcp->hex_buf, key);
+	    vstream_fprintf(dict_tcp->fp, "get %s\n", STR(dict_tcp->hex_buf));
+	    if (msg_verbose)
+		msg_info("%s: send: get %s", myname, STR(dict_tcp->hex_buf));
+	    last_ch = vstring_get_nonl_bound(dict_tcp->hex_buf, dict_tcp->fp,
+					     DICT_TCP_MAXLEN);
+	    if (last_ch == '\n')
+		break;
+
+	    /*
+	     * Disconnect from the server if it can't talk to us.
+	     */
+	    if (last_ch < 0)
+		msg_warn("read TCP map reply from %s: unexpected EOF (%m)",
+			 dict_tcp->dict.name);
+	    else
+		msg_warn("read TCP map reply from %s: text longer than %d",
+			 dict_tcp->dict.name, DICT_TCP_MAXLEN);
+	    dict_tcp_disconnect(dict_tcp);
+	}
+
+	/*
+	 * Try to connect a limited number of times before giving up.
+	 */
+	if (++tries >= DICT_TCP_MAXTRY)
+	    RETURN(DICT_ERR_RETRY, 0);
+
+	/*
+	 * Sleep between attempts, instead of hammering the server.
+	 */
+	sleep(1);
+    }
+    if (msg_verbose)
+	msg_info("%s: recv: %s", myname, STR(dict_tcp->hex_buf));
+
+    /*
+     * Check the general reply syntax. If the reply is malformed, disconnect
+     * and try again later.
+     */
+    if (start = STR(dict_tcp->hex_buf),
+	!ISDIGIT(start[0]) || !ISDIGIT(start[1])
+	|| !ISDIGIT(start[2]) || !ISSPACE(start[3])
+	|| !hex_unquote(dict_tcp->raw_buf, start + 4)) {
+	msg_warn("read TCP map reply from %s: malformed reply: %.100s",
+	       dict_tcp->dict.name, printable(STR(dict_tcp->hex_buf), '_'));
+	dict_tcp_disconnect(dict_tcp);
+	RETURN(DICT_ERR_RETRY, 0);
+    }
+
+    /*
+     * Examine the reply status code. If the reply is malformed, disconnect
+     * and try again later.
+     */
+    switch (start[0]) {
+    default:
+	msg_warn("read TCP map reply from %s: bad status code: %.100s",
+	       dict_tcp->dict.name, printable(STR(dict_tcp->hex_buf), '_'));
+	dict_tcp_disconnect(dict_tcp);
+	RETURN(DICT_ERR_RETRY, 0);
+    case '4':
+	if (msg_verbose)
+	    msg_info("%s: soft error: %s",
+		     myname, printable(STR(dict_tcp->hex_buf), '_'));
+	dict_tcp_disconnect(dict_tcp);
+	RETURN(DICT_ERR_RETRY, 0);
+    case '5':
+	if (msg_verbose)
+	    msg_info("%s: not found: %s",
+		     myname, printable(STR(dict_tcp->hex_buf), '_'));
+	RETURN(DICT_ERR_NONE, 0);
+    case '2':
+	if (msg_verbose)
+	    msg_info("%s: found: %s",
+		     myname, printable(STR(dict_tcp->raw_buf), '_'));
+	RETURN(DICT_ERR_NONE, STR(dict_tcp->raw_buf));
+    }
+}
+
+/* dict_tcp_close - close TCP map */
+
+static void dict_tcp_close(DICT *dict)
+{
+    DICT_TCP *dict_tcp = (DICT_TCP *) dict;
+
+    if (dict_tcp->fp)
+	(void) vstream_fclose(dict_tcp->fp);
+    if (dict_tcp->raw_buf)
+	vstring_free(dict_tcp->raw_buf);
+    if (dict_tcp->hex_buf)
+	vstring_free(dict_tcp->hex_buf);
+    if (dict->fold_buf)
+	vstring_free(dict->fold_buf);
+    dict_free(dict);
+}
+
+/* dict_tcp_open - open TCP map */
+
+DICT   *dict_tcp_open(const char *map, int open_flags, int dict_flags)
+{
+    DICT_TCP *dict_tcp;
+
+    /*
+     * Sanity checks.
+     */
+    if (dict_flags & DICT_FLAG_NO_UNAUTH)
+	return (dict_surrogate(DICT_TYPE_TCP, map, open_flags, dict_flags,
+		     "%s:%s map is not allowed for security sensitive data",
+			       DICT_TYPE_TCP, map));
+    if (open_flags != O_RDONLY)
+	return (dict_surrogate(DICT_TYPE_TCP, map, open_flags, dict_flags,
+			       "%s:%s map requires O_RDONLY access mode",
+			       DICT_TYPE_TCP, map));
+
+    /*
+     * Create the dictionary handle. Do not open the connection until the
+     * first request is made.
+     */
+    dict_tcp = (DICT_TCP *) dict_alloc(DICT_TYPE_TCP, map, sizeof(*dict_tcp));
+    dict_tcp->fp = 0;
+    dict_tcp->raw_buf = dict_tcp->hex_buf = 0;
+    dict_tcp->dict.lookup = dict_tcp_lookup;
+    dict_tcp->dict.close = dict_tcp_close;
+    dict_tcp->dict.flags = dict_flags | DICT_FLAG_PATTERN;
+    if (dict_flags & DICT_FLAG_FOLD_MUL)
+	dict_tcp->dict.fold_buf = vstring_alloc(10);
+
+    return (DICT_DEBUG (&dict_tcp->dict));
+}