MINOR: cfgparse: add str2receiver() to parse dgram receivers

This is at least temporary, as the migration at once is way too difficuly.
For now it still creates listeners but only allows DGRAM sockets. This
aims at easing the split between listeners and receivers.

include/haproxy/cfgparse.h

@@ -96,6 +96,7 @@ void cfg_unregister_keywords(struct cfg_kw_list *kwl);
 void init_default_instance();
 int check_config_validity();
 int str2listener(char *str, struct proxy *curproxy, struct bind_conf *bind_conf, const char *file, int line, char **err);
+int str2receiver(char *str, struct proxy *curproxy, struct bind_conf *bind_conf, const char *file, int line, char **err);
 int cfg_register_section(char *section_name,
                          int (*section_parser)(const char *, int, char **, int),
                          int (*post_section_parser)());

src/cfgparse.c

@@ -146,6 +146,55 @@ int str2listener(char *str, struct proxy *curproxy, struct bind_conf *bind_conf,
 	return 0;
 }
 
+/*
+ * converts <str> to a list of datagram-oriented listeners which are dynamically
+ * allocated.
+ * The format is "{addr|'*'}:port[-end][,{addr|'*'}:port[-end]]*", where :
+ *  - <addr> can be empty or "*" to indicate INADDR_ANY ;
+ *  - <port> is a numerical port from 1 to 65535 ;
+ *  - <end> indicates to use the range from <port> to <end> instead (inclusive).
+ * This can be repeated as many times as necessary, separated by a coma.
+ * Function returns 1 for success or 0 if error. In case of errors, if <err> is
+ * not NULL, it must be a valid pointer to either NULL or a freeable area that
+ * will be replaced with an error message.
+ */
+int str2receiver(char *str, struct proxy *curproxy, struct bind_conf *bind_conf, const char *file, int line, char **err)
+{
+	char *next, *dupstr;
+	int port, end;
+
+	next = dupstr = strdup(str);
+
+	while (next && *next) {
+		struct sockaddr_storage *ss2;
+		int fd = -1;
+
+		str = next;
+		/* 1) look for the end of the first address */
+		if ((next = strchr(str, ',')) != NULL) {
+			*next++ = 0;
+		}
+
+		ss2 = str2sa_range(str, NULL, &port, &end, &fd, err,
+		                   curproxy == global.stats_fe ? NULL : global.unix_bind.prefix,
+		                   NULL, PA_O_RESOLVE | PA_O_PORT_OK | PA_O_PORT_MAND | PA_O_PORT_RANGE |
+		                          PA_O_SOCKET_FD | PA_O_DGRAM | PA_O_XPRT);
+		if (!ss2)
+			goto fail;
+
+		/* OK the address looks correct */
+		if (!create_listeners(bind_conf, ss2, port, end, fd, err)) {
+			memprintf(err, "%s for address '%s'.\n", *err, str);
+			goto fail;
+		}
+	} /* end while(next) */
+	free(dupstr);
+	return 1;
+ fail:
+	free(dupstr);
+	return 0;
+}
+
 /*
  * Report an error in <msg> when there are too many arguments. This version is
  * intended to be used by keyword parsers so that the message will be included