to rewrite domain on incoming mails, we need to be able to extract

rfc822 addresses from some headers and parse them into a structure
that we can easily manipulate.

this implementation will parse addresses in the following formats:
	user, user <addr>, "user" <addr>, "user name" <addr>

2 files changed, 191 insertions, 0 deletions

diff --git a/usr.sbin/smtpd/rfc822.c b/usr.sbin/smtpd/rfc822.c
new file mode 100644
index 00000000000..b598fa1ff07
--- /dev/null
+++ b/usr.sbin/smtpd/rfc822.c
@@ -0,0 +1,148 @@
+/*	$OpenBSD: rfc822.c,v 1.1 2014/10/12 18:54:31 gilles Exp $	*/
+
+/*
+ * Copyright (c) 2014 Gilles Chehade <gilles@poolp.org>
+ *
+ * Permission to use, copy, modify, and distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ */
+
+#include <sys/types.h>
+#include <sys/queue.h>
+#include <sys/tree.h>
+
+#include <ctype.h>
+#include <errno.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+
+#include "rfc822.h"
+
+static int
+parse_addresses(struct rfc822_parser *rp, const char *buffer, size_t len)
+{
+	const char		*s;
+	char			*wptr;
+	struct rfc822_address	*ra;
+
+	s = buffer;
+
+	/* skip over whitespaces */
+	for (s = buffer; *s && isspace(*s); ++s, len--)
+		;
+
+	/* we should now pointing to the beginning of a recipient */
+	if (*s == '\0')
+		return 0;
+
+	ra = calloc(1, sizeof *ra);
+	if (ra == NULL)
+		return -1;
+
+	wptr = ra->name;
+	for (; len; s++, len--) {
+		if (*s == '(' && !rp->escape && !rp->quote)
+			rp->comment++;
+		if (*s == '"' && !rp->escape && !rp->comment)
+			rp->quote = !rp->quote;
+		if (!rp->comment && !rp->quote && !rp->escape) {
+			if (*s == '<' && rp->bracket)
+				return 0;
+			if (*s == '>' && !rp->bracket)
+				return 0;
+
+			if (*s == '<') {
+				wptr = ra->address;
+				rp->bracket++;
+				continue;
+			}
+			if (*s == '>') {
+				rp->bracket--;
+				continue;
+			}
+			if (*s == ',' || *s == ';')
+				break;
+		}
+		if (*s == ')' && !rp->escape && !rp->quote && rp->comment)
+			rp->comment--;
+		if (*s == '\\' && !rp->escape && !rp->comment && !rp->quote)
+			rp->escape = 1;
+		else
+			rp->escape = 0;
+		*wptr++ = *s;
+	}
+
+	/* no value, malformed header */
+	if (ra->name[0] == '\0' && ra->address[0] == '\0')
+		return 0;
+
+	/* no <>, use name as address */
+	if (ra->address[0] == '\0') {
+		memcpy(ra->address, ra->name, sizeof ra->address);
+		memset(ra->name, 0, sizeof ra->name);
+	}
+
+	/* strip first trailing whitespace from name */
+	wptr = &ra->name[0] + strlen(ra->name);
+	while (wptr != &ra->name[0]) {
+		if (*wptr && ! isspace(*wptr))
+			break;
+		*wptr-- = '\0';
+	}
+
+	TAILQ_INSERT_TAIL(&rp->addresses, ra, next);
+
+	/* do we have more to process ? */
+	for (; *s; ++s, --len)
+		if (*s == ',' || *s == ';')
+			break;
+
+	/* nope, we're done */
+	if (*s == '\0')
+		return 1;
+
+	/* there's more to come */
+	if (*s == ',' || *s == ';') {
+		s++;
+		len--;
+	}
+	if (len)
+		return parse_addresses(rp, s, len);
+	return 1;
+}
+
+void
+rfc822_parser_init(struct rfc822_parser *rp)
+{
+	memset(rp, 0, sizeof *rp);
+	TAILQ_INIT(&rp->addresses);
+}
+
+void
+rfc822_parser_reset(struct rfc822_parser *rp)
+{
+	struct rfc822_address	*ra;
+
+	while ((ra = TAILQ_FIRST(&rp->addresses))) {
+		TAILQ_REMOVE(&rp->addresses, ra, next);
+		free(ra);
+	}
+	memset(rp, 0, sizeof *rp);
+}
+
+int
+rfc822_parser_feed(struct rfc822_parser *rp, const char *line)
+{
+	return parse_addresses(rp, line, strlen(line));
+}
diff --git a/usr.sbin/smtpd/rfc822.h b/usr.sbin/smtpd/rfc822.h
new file mode 100644
index 00000000000..0e602e23d21
--- /dev/null
+++ b/usr.sbin/smtpd/rfc822.h
@@ -0,0 +1,43 @@
+/*	$OpenBSD: rfc822.h,v 1.1 2014/10/12 18:54:31 gilles Exp $	*/
+
+/*
+ * Copyright (c) 2014 Gilles Chehade <gilles@poolp.org>
+ *
+ * Permission to use, copy, modify, and distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ */
+
+#ifndef _RFC822_H_
+#define	_RFC822_H_
+
+#define	RFC822_MAX_LINE_SIZE	998
+
+struct rfc822_address {
+	TAILQ_ENTRY(rfc822_address)	next;
+	char				name[RFC822_MAX_LINE_SIZE+1];
+	char				address[RFC822_MAX_LINE_SIZE+1];
+};
+
+struct rfc822_parser {
+	TAILQ_HEAD(addresses, rfc822_address)	addresses;
+
+	uint8_t				quote;
+	uint8_t				comment;
+	uint8_t				escape;
+	uint8_t				bracket;
+};
+
+void	rfc822_parser_init(struct rfc822_parser *);
+void	rfc822_parser_reset(struct rfc822_parser *);
+int	rfc822_parser_feed(struct rfc822_parser *, const char *);
+
+#endif