logger: Add support to logger for RFC6587 octet counting

This patch adds support to logger for RFC6587 octet counting.
RFC6587 provides support for two sorts of framing:

1. Octet counting (at RFC6587 s3.4.1)

   In essence each frame is preceded by a decimal length and a
   space.

2. Non-transparent framing (at RFC6587 s3.4.2), also called
   'octet stuffing'

   In essence each frame is terminated by a `\n`

Prior to this patch, logger used option 2 (non-transparent framing)
on TCP, and used no framing on UDP. After this patch, the default
behaviour is unchanged, but if the '--octet-count' option is supplied,
option 1 is used for both TCP and UDP. Arguably octet count framing
makes little sense on UDP, but some servers provide it and this
allows testing of those servers.

Signed-off-by: Alex Bligh <alex@alex.org.uk>

diff --git a/misc-utils/logger.1 b/misc-utils/logger.1
index bb81295a1d05db66bf7eef5ae0a68c9a1b207012..36c923d52cc2f8911b6bc44520db8e327ec414ac 100644 (file)
--- a/misc-utils/logger.1
+++ b/misc-utils/logger.1
@@ -179,6 +179,11 @@ The RFC 5424 protocol has been the default for
 .B logger
 since version 2.26.
 .TP
+.B \-\-octet\-count
+Use the RFC 6587 octet counting framing method for sending messages. When
+this option is not used, the default is no framing on UDP, and RFC6587
+non-transparent-framing (also known as octet stuffing) on TCP.
+.TP
 .BR \-s , " \-\-stderr"
 Output the message to standard error as well as to the system log.
 .TP

diff --git a/misc-utils/logger.c b/misc-utils/logger.c
index 9947b75e42b3c359f36b2b850c2e45bcdc86a5e6..181121a29cd17ccc46817a2f1e072d6ab07d9a82 100644 (file)
--- a/misc-utils/logger.c
+++ b/misc-utils/logger.c
@@ -92,7 +92,8 @@ enum {
        OPT_SOCKET_ERRORS,
        OPT_MSGID,
        OPT_NOACT,
-       OPT_ID
+       OPT_ID,
+       OPT_OCTET_COUNT
 };
 
 struct logger_ctl {
@@ -116,7 +117,8 @@ struct logger_ctl {
                        rfc5424_time:1,         /* include time stamp */
                        rfc5424_tq:1,           /* include time quality markup */
                        rfc5424_host:1,         /* include hostname */
-                       skip_empty_lines:1; /* do not send empty lines when processing files */
+                       skip_empty_lines:1,     /* do not send empty lines when processing files */
+                       octet_count:1;          /* use RFC6587 octet counting */
 };
 
 /*
@@ -373,19 +375,22 @@ static const char *rfc3164_current_time(void)
 }
 
 /* writes generated buffer to desired destination. For TCP syslog,
- * we use RFC6587 octet-stuffing. This is not great, but doing
- * full blown RFC5425 (TLS) looks like it is too much for the
- * logger utility.
+ * we use RFC6587 octet-stuffing (unless octet-counting is selected).
+ * This is not great, but doing full blown RFC5425 (TLS) looks like
+ * it is too much for the logger utility. If octet-counting is
+ * selected, we use that.
  */
 static void write_output(const struct logger_ctl *ctl, const char *const msg)
 {
        char *buf;
-       const size_t len = xasprintf(&buf, "%s%s", ctl->hdr, msg);
+       const size_t len = ctl->octet_count ?
+               xasprintf(&buf, "%zu %s%s", strlen(ctl->hdr)+strlen(msg), ctl->hdr, msg):
+               xasprintf(&buf, "%s%s", ctl->hdr, msg);
 
        if (!ctl->noact) {
                if (write_all(ctl->fd, buf, len) < 0)
                        warn(_("write failed"));
-               else if (ctl->socket_type == TYPE_TCP) {
+               else if ((ctl->socket_type == TYPE_TCP) && !ctl->octet_count) {
                        /* using an additional write seems like the best compromise:
                         * - writev() is not yet supported by framework
                         * - adding the \n to the buffer in formatters violates layers
@@ -706,6 +711,7 @@ static void __attribute__ ((__noreturn__)) usage(FILE *out)
        fputs(_(" -e, --skip-empty         do not log empty lines when processing files\n"), out);
        fputs(_("     --no-act             do everything except the write the log\n"), out);
        fputs(_(" -p, --priority <prio>    mark given message with this priority\n"), out);
+       fputs(_("     --octet-count        use rfc6587 octet counting\n"), out);
        fputs(_("     --prio-prefix        look for a prefix on every line read from stdin\n"), out);
        fputs(_(" -s, --stderr             output message to standard error as well\n"), out);
        fputs(_(" -S, --size <size>        maximum size for a single message\n"), out);
@@ -781,6 +787,7 @@ int main(int argc, char **argv)
                { "port",          required_argument, 0, 'P'               },
                { "version",       no_argument,       0, 'V'               },
                { "help",          no_argument,       0, 'h'               },
+               { "octet-count",   no_argument,       0, OPT_OCTET_COUNT   },
                { "prio-prefix",   no_argument,       0, OPT_PRIO_PREFIX   },
                { "rfc3164",       no_argument,       0, OPT_RFC3164       },
                { "rfc5424",       optional_argument, 0, OPT_RFC5424       },
@@ -855,6 +862,9 @@ int main(int argc, char **argv)
                        exit(EXIT_SUCCESS);
                case 'h':
                        usage(stdout);
+               case OPT_OCTET_COUNT:
+                       ctl.octet_count = 1;
+                       break;
                case OPT_PRIO_PREFIX:
                        ctl.prio_prefix = 1;
                        break;