1 files changed, 215 insertions, 0 deletions
diff --git a/src/smtp/smtp_key.c b/src/smtp/smtp_key.c
new file mode 100644
index 0000000..643f4db
--- /dev/null
+++ b/src/smtp/smtp_key.c
@@ -0,0 +1,215 @@
+/*++
+/* NAME
+/*	smtp_key 3
+/* SUMMARY
+/*	cache/table lookup key management
+/* SYNOPSIS
+/*	#include "smtp.h"
+/*
+/*	char	*smtp_key_prefix(buffer, delim_na, iterator, context_flags)
+/*	VSTRING	*buffer;
+/*	const char *delim_na;
+/*	SMTP_ITERATOR *iterator;
+/*	int	context_flags;
+/* DESCRIPTION
+/*	The Postfix SMTP server accesses caches and lookup tables,
+/*	using lookup keys that contain information from various
+/*	contexts: per-server configuration, per-request envelope,
+/*	and results from DNS queries.
+/*
+/*	These lookup keys sometimes share the same context information.
+/*	The primary purpose of this API is to ensure that this
+/*	shared context is used consistently, and that its use is
+/*	made explicit (both are needed to verify that there is no
+/*	false cache sharing).
+/*
+/*	smtp_key_prefix() constructs a lookup key prefix from context
+/*	that may be shared with other lookup keys. The user is free
+/*	to append additional application-specific context. The result
+/*	value is a pointer to the result text.
+/*
+/*	Arguments:
+/* .IP buffer
+/*	Storage for the result.
+/* .IP delim_na
+/*	The field delimiter character, and the optional place holder
+/*	character for a) information that is unavailable, b)
+/*	information that is inapplicable, or c) that would result
+/*	in an empty field.  Key fields that contain "delim_na"
+/*	characters will be base64-encoded.
+/*	Do not specify "delim_na" characters that are part of the
+/*	base64 character set.
+/* .IP iterator
+/*	Information that will be selected by the specified flags.
+/* .IP context_flags
+/*	Bit-wise OR of one or more of the following.
+/* .RS
+/* .IP SMTP_KEY_FLAG_SERVICE
+/*	The global service name. This is a proxy for
+/*	destination-independent and request-independent context.
+/* .IP SMTP_KEY_FLAG_SENDER
+/*	The envelope sender address. This is a proxy for sender-dependent
+/*	context, such as per-sender SASL authentication.
+/* .IP SMTP_KEY_FLAG_REQ_NEXTHOP
+/*	The delivery request nexthop destination, including optional
+/*	[] and :port (the same form that users specify in a SASL
+/*	password or TLS policy lookup table). This is a proxy for
+/*	destination-dependent, but host-independent context.
+/* .IP SMTP_KEY_FLAG_CUR_NEXTHOP
+/*	The current iterator's nexthop destination (delivery request
+/*	nexthop or fallback nexthop, including optional [] and
+/*	:port).
+/* .IP SMTP_KEY_FLAG_HOSTNAME
+/*	The current iterator's remote hostname.
+/* .IP SMTP_KEY_FLAG_ADDR
+/*	The current iterator's remote address.
+/* .IP SMTP_KEY_FLAG_PORT
+/*	The current iterator's remote port.
+/* .RE
+/* DIAGNOSTICS
+/*	Panic: undefined flag or zero flags. Fatal: out of memory.
+/* 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
+/*
+/*	Wietse Venema
+/*	Google, Inc.
+/*	111 8th Avenue
+/*	New York, NY 10011, USA
+/*--*/
+
+ /*
+  * System library.
+  */
+#include <sys_defs.h>
+#include <netinet/in.h>			/* ntohs() for Solaris or BSD */
+#include <arpa/inet.h>			/* ntohs() for Linux or BSD */
+#include <string.h>
+
+ /*
+  * Utility library.
+  */
+#include <msg.h>
+#include <vstring.h>
+#include <base64_code.h>
+
+ /*
+  * Global library.
+  */
+#include <mail_params.h>
+
+ /*
+  * Application-specific.
+  */
+#include <smtp.h>
+
+ /*
+  * We use a configurable field terminator and optional place holder for data
+  * that is unavailable or inapplicable. We base64-encode content that
+  * contains these characters, and content that needs obfuscation.
+  */
+
+/* smtp_key_append_na - append place-holder key field */
+
+static void smtp_key_append_na(VSTRING *buffer, const char *delim_na)
+{
+    if (delim_na[1] != 0)
+	VSTRING_ADDCH(buffer, delim_na[1]);
+    VSTRING_ADDCH(buffer, delim_na[0]);
+}
+
+/* smtp_key_append_str - append string-valued key field */
+
+static void smtp_key_append_str(VSTRING *buffer, const char *str,
+				        const char *delim_na)
+{
+    if (str == 0 || str[0] == 0) {
+	smtp_key_append_na(buffer, delim_na);
+    } else if (str[strcspn(str, delim_na)] != 0) {
+	base64_encode_opt(buffer, str, strlen(str), BASE64_FLAG_APPEND);
+	VSTRING_ADDCH(buffer, delim_na[0]);
+    } else {
+	vstring_sprintf_append(buffer, "%s%c", str, delim_na[0]);
+    }
+}
+
+/* smtp_key_append_uint - append unsigned-valued key field */
+
+static void smtp_key_append_uint(VSTRING *buffer, unsigned num,
+				         const char *delim_na)
+{
+    vstring_sprintf_append(buffer, "%u%c", num, delim_na[0]);
+}
+
+/* smtp_key_prefix - format common elements in lookup key */
+
+char   *smtp_key_prefix(VSTRING *buffer, const char *delim_na,
+			        SMTP_ITERATOR *iter, int flags)
+{
+    static const char myname[] = "smtp_key_prefix";
+    SMTP_STATE *state = iter->parent;	/* private member */
+
+    /*
+     * Sanity checks.
+     */
+    if (state == 0)
+	msg_panic("%s: no parent state", myname);
+    if (flags & ~SMTP_KEY_MASK_ALL)
+	msg_panic("%s: unknown key flags 0x%x",
+		  myname, flags & ~SMTP_KEY_MASK_ALL);
+    if (flags == 0)
+	msg_panic("%s: zero flags", myname);
+
+    /*
+     * Initialize.
+     */
+    VSTRING_RESET(buffer);
+
+    /*
+     * Per-service and per-request context.
+     */
+    if (flags & SMTP_KEY_FLAG_SERVICE)
+	smtp_key_append_str(buffer, state->service, delim_na);
+    if (flags & SMTP_KEY_FLAG_SENDER)
+	smtp_key_append_str(buffer, state->request->sender, delim_na);
+
+    /*
+     * Per-destination context, non-canonicalized form.
+     */
+    if (flags & SMTP_KEY_FLAG_REQ_NEXTHOP)
+	smtp_key_append_str(buffer, STR(iter->request_nexthop), delim_na);
+    if (flags & SMTP_KEY_FLAG_CUR_NEXTHOP)
+	smtp_key_append_str(buffer, STR(iter->dest), delim_na);
+
+    /*
+     * Per-host context, canonicalized form.
+     */
+    if (flags & SMTP_KEY_FLAG_HOSTNAME)
+	smtp_key_append_str(buffer, STR(iter->host), delim_na);
+    if (flags & SMTP_KEY_FLAG_ADDR)
+	smtp_key_append_str(buffer, STR(iter->addr), delim_na);
+    if (flags & SMTP_KEY_FLAG_PORT)
+	smtp_key_append_uint(buffer, ntohs(iter->port), delim_na);
+
+    /*
+     * Requested TLS level, if applicable. TODO(tlsproxy) should the lookup
+     * engine also try the requested TLS level and 'stronger', in case a
+     * server hosts multiple domains with different TLS requirements?
+     */
+    if (flags & SMTP_KEY_FLAG_TLS_LEVEL)
+#ifdef USE_TLS
+	smtp_key_append_uint(buffer, state->tls->level, delim_na);
+#else
+	smtp_key_append_na(buffer, delim_na);
+#endif
+
+    VSTRING_TERMINATE(buffer);
+
+    return STR(buffer);
+}