MEDIUM: logs: add support for RFC5424 header format per logger

The function __send_log() iterates over senders and passes the header as
the first vector to sendmsg(), thus it can send a logger-specific header
in each message.

A new logger arguments "format rfc5424" should be used in order to enable
RFC5424 header format. For example:

    log 10.2.3.4:1234 len 2048 format rfc5424 local2 info

include/proto/log.h

@@ -39,7 +39,12 @@ extern char *log_format;
 extern char default_tcp_log_format[];
 extern char default_http_log_format[];
 extern char clf_http_log_format[];
+
+extern char default_host_tag_pid_log_format[];
+extern char rfc5424_host_tag_pid_log_format[];
+
 extern char *logheader;
+extern char *logheader_rfc5424;
 extern char *logline;
 
 
@@ -108,6 +113,11 @@ void send_log(struct proxy *p, int level, const char *format, ...)
 
 void __send_log(struct proxy *p, int level, char *message, size_t size);
 
+/*
+ * returns log format for <fmt> or -1 if not found.
+ */
+int get_log_format(const char *fmt);
+
 /*
  * returns log level for <lev> or -1 if not found.
  */
@@ -141,7 +151,7 @@ char *lf_port(char *dst, struct sockaddr *sockaddr, size_t size, struct logforma
 /*
  * Write hostname, log_tag and pid to the log string
  */
-char *lf_host_tag_pid(char *dst, const char *hostname, const char *log_tag, int pid, size_t size);
+char *lf_host_tag_pid(char *dst, const char *format, const char *hostname, const char *log_tag, int pid, size_t size);
 
 
 #endif /* _PROTO_LOG_H */

include/types/log.h

@@ -37,6 +37,13 @@
 /* The array containing the names of the log levels. */
 extern const char *log_levels[];
 
+/* enum for log format */
+enum {
+	LOG_FORMAT_RFC3164 = 0,
+	LOG_FORMAT_RFC5424,
+	LOG_FORMATS,          /* number of supported log formats, must always be last */
+};
+
 /* lists of fields that can be logged */
 enum {
 
@@ -158,6 +165,7 @@ struct logformat_node {
 struct logsrv {
 	struct list list;
 	struct sockaddr_storage addr;
+	int format;
 	int facility;
 	int level;
 	int minlvl;

include/types/proxy.h

@@ -346,7 +346,8 @@ struct proxy {
 	struct list logsrvs;
 	struct list logformat; 			/* log_format linked list */
 	char *log_tag;                          /* override default syslog tag */
-	struct chunk log_htp;			/* a syslog header part that contains hostname, log_tag and pid */
+	struct chunk log_htp;			/* a syslog header part that contains hostname, log_tag and pid (RFC3164 format) */
+	struct chunk log_htp_rfc5424;		/* a syslog header part that contains hostname, log_tag and pid (RFC5424 format) */
 	char *header_unique_id; 		/* unique-id header */
 	struct list format_unique_id;		/* unique-id format */
 	int to_log;				/* things to be logged (LW_*) */

src/cfgparse.c

@@ -1572,9 +1572,23 @@ int cfg_parse_global(const char *file, int linenum, char **args, int kwm)
 		if (logsrv->maxlen > global.max_syslog_len) {
 			global.max_syslog_len = logsrv->maxlen;
 			logheader = realloc(logheader, global.max_syslog_len + 1);
+			logheader_rfc5424 = realloc(logheader_rfc5424, global.max_syslog_len + 1);
 			logline = realloc(logline, global.max_syslog_len + 1);
 		}
 
+		/* after the length, a format may be specified */
+		if (strcmp(args[arg+2], "format") == 0) {
+			logsrv->format = get_log_format(args[arg+3]);
+			if (logsrv->format < 0) {
+				Alert("parsing [%s:%d] : unknown log format '%s'\n", file, linenum, args[arg+3]);
+				err_code |= ERR_ALERT | ERR_FATAL;
+				goto out;
+			}
+
+			/* skip these two args */
+			arg += 2;
+		}
+
 		if (alertif_too_many_args_idx(3, arg + 1, file, linenum, args, &err_code))
 			goto out;
 
@@ -5855,9 +5869,23 @@ stats_error_parsing:
 			if (logsrv->maxlen > global.max_syslog_len) {
 				global.max_syslog_len = logsrv->maxlen;
 				logheader = realloc(logheader, global.max_syslog_len + 1);
+				logheader_rfc5424 = realloc(logheader_rfc5424, global.max_syslog_len + 1);
 				logline = realloc(logline, global.max_syslog_len + 1);
 			}
 
+			/* after the length, a format may be specified */
+			if (strcmp(args[arg+2], "format") == 0) {
+				logsrv->format = get_log_format(args[arg+3]);
+				if (logsrv->format < 0) {
+					Alert("parsing [%s:%d] : unknown log format '%s'\n", file, linenum, args[arg+3]);
+					err_code |= ERR_ALERT | ERR_FATAL;
+					goto out;
+				}
+
+				/* skip these two args */
+				arg += 2;
+			}
+
 			if (alertif_too_many_args_idx(3, arg + 1, file, linenum, args, &err_code))
 				goto out;
 
@@ -7217,6 +7245,7 @@ int check_config_validity()
 		struct sticking_rule *mrule;
 		struct act_rule *trule;
 		struct act_rule *hrqrule;
+		struct logsrv *tmplogsrv;
 		unsigned int next_id;
 		int nbproc;
 
@@ -7819,25 +7848,62 @@ int check_config_validity()
 out_uri_auth_compat:
 
 		/* write a syslog header string that contains hostname, log_tag and pid */
-		curproxy->log_htp.str = lf_host_tag_pid(logheader,
-		                                        global.log_send_hostname ? global.log_send_hostname : "",
-		                                        curproxy->log_tag ? curproxy->log_tag : global.log_tag, pid,
-		                                        global.max_syslog_len);
+		list_for_each_entry(tmplogsrv, &curproxy->logsrvs, list) {
+			char *hdr;
+			struct chunk *htp;
+			char *htp_fmt;
+			char *host = global.log_send_hostname;
 
-		if ((curproxy->log_htp.str == NULL) ||
-		    (curproxy->log_htp.len = curproxy->log_htp.str - logheader) >= global.max_syslog_len) {
-			Alert("Proxy '%s': cannot write a syslog header string that contains "
-			      "hostname, log_tag and pid.\n",
-			      curproxy->id);
-			cfgerr++;
-		}
-		else {
-			curproxy->log_htp.str = (char *)malloc(curproxy->log_htp.len);
-			memcpy(curproxy->log_htp.str, logheader, curproxy->log_htp.len);
-			curproxy->log_htp.size = 0;
-		}
+			switch (tmplogsrv->format) {
+			case LOG_FORMAT_RFC3164:
+				hdr = logheader;
+				htp = &curproxy->log_htp;
+				htp_fmt = default_host_tag_pid_log_format;
+				host = host ? host : "";
+				break;
 
-		logheader[0] = 0;
+			case LOG_FORMAT_RFC5424:
+				hdr = logheader_rfc5424;
+				htp = &curproxy->log_htp_rfc5424;
+				htp_fmt = rfc5424_host_tag_pid_log_format;
+				break;
+
+			default:
+				continue; /* must never happen */
+			}
+
+			if (htp->str)
+				continue;
+
+			if (!host) {
+				int len = strlen(hostname);
+				host = malloc(len + 2);
+				snprintf(host, len + 2, "%s ", hostname);
+			}
+
+			htp->str = lf_host_tag_pid(hdr, htp_fmt, host,
+			                           curproxy->log_tag ? curproxy->log_tag : global.log_tag,
+			                           pid, global.max_syslog_len);
+
+			if ((host != global.log_send_hostname) && strlen(host))
+				free(host);
+
+			if ((htp->str == NULL) ||
+			    ((htp->len = htp->str - hdr) >= global.max_syslog_len)) {
+				Alert("Proxy '%s': cannot write a syslog header string that contains "
+				      "hostname, log_tag and pid.\n",
+				      curproxy->id);
+				cfgerr++;
+				goto out_host_tag_pid;
+			}
+
+			htp->str = (char *)malloc(htp->len);
+			memcpy(htp->str, hdr, htp->len);
+			htp->size = 0;
+
+			hdr[0] = 0;
+		}
+out_host_tag_pid:
 
 		/* compile the log format */
 		if (!(curproxy->cap & PR_CAP_FE)) {

src/haproxy.c

@@ -1329,6 +1329,7 @@ void deinit(void)
 			free(log);
 		}
 		chunk_destroy(&p->log_htp);
+		chunk_destroy(&p->log_htp_rfc5424);
 
 		list_for_each_entry_safe(lf, lfb, &p->logformat, list) {
 			LIST_DEL(&lf->list);

src/log.c

@@ -41,6 +41,11 @@
 #include <proto/ssl_sock.h>
 #endif
 
+const char *log_formats[LOG_FORMATS] = {
+	[LOG_FORMAT_RFC3164] = "rfc3164",
+	[LOG_FORMAT_RFC5424] = "rfc5424"
+};
+
 const char *log_facilities[NB_LOG_FACILITIES] = {
 	"kern", "user", "mail", "daemon",
 	"auth", "syslog", "lpr", "news",
@@ -50,7 +55,6 @@ const char *log_facilities[NB_LOG_FACILITIES] = {
 	"local4", "local5", "local6", "local7"
 };
 
-
 const char *log_levels[NB_LOG_LEVELS] = {
 	"emerg", "alert", "crit", "err",
 	"warning", "notice", "info", "debug"
@@ -151,11 +155,20 @@ char clf_http_log_format[] = "%{+Q}o %{-Q}ci - - [%T] %r %ST %B \"\" \"\" %cp %m
 char default_tcp_log_format[] = "%ci:%cp [%t] %ft %b/%s %Tw/%Tc/%Tt %B %ts %ac/%fc/%bc/%sc/%rc %sq/%bq";
 char *log_format = NULL;
 
-/* This is a global syslog header, common to all outgoing messages. It
- * begins with time-based part and is updated by update_log_hdr().
+char default_host_tag_pid_log_format[] = "%s%s[%d]: ";
+char rfc5424_host_tag_pid_log_format[] = "%s%s %d - - ";
+
+/* This is a global syslog header, common to all outgoing messages in
+ * RFC3164 format. It begins with time-based part and is updated by
+ * update_log_hdr().
  */
 char *logheader = NULL;
 
+/* This is a global syslog header for messages in RFC5424 format. It is
+ * updated by update_log_hdr_rfc5424().
+ */
+char *logheader_rfc5424 = NULL;
+
 /* This is a global syslog message buffer, common to all outgoing
  * messages. It contains only the data part.
  */
@@ -617,6 +630,20 @@ void qfprintf(FILE *out, const char *fmt, ...)
 	}
 }
 
+/*
+ * returns log format for <fmt> or -1 if not found.
+ */
+int get_log_format(const char *fmt)
+{
+	int format;
+
+	format = LOG_FORMATS - 1;
+	while (format >= 0 && strcmp(log_formats[format], fmt))
+		format--;
+
+	return format;
+}
+
 /*
  * returns log level for <lev> or -1 if not found.
  */
@@ -631,7 +658,6 @@ int get_log_level(const char *lev)
 	return level;
 }
 
-
 /*
  * returns log facility for <fac> or -1 if not found.
  */
@@ -739,12 +765,12 @@ char *lf_port(char *dst, struct sockaddr *sockaddr, size_t size, struct logforma
 	return ret;
 }
 
-char *lf_host_tag_pid(char *dst, const char *hostname, const char *log_tag, int pid, size_t size)
+char *lf_host_tag_pid(char *dst, const char *format, const char *hostname, const char *log_tag, int pid, size_t size)
 {
 	char *ret = dst;
 	int iret;
 
-	iret = snprintf(dst, size, "%s%s[%d]: ", hostname, log_tag, pid);
+	iret = snprintf(dst, size, format, hostname, log_tag, pid);
 	if (iret < 0 || iret > size)
 		return NULL;
 	ret += iret;
@@ -752,10 +778,11 @@ char *lf_host_tag_pid(char *dst, const char *hostname, const char *log_tag, int
 	return ret;
 }
 
-/* Re-generate the syslog header at the beginning of logheader once a second and
- * return the pointer to the first character after the header.
+/* Re-generate time-based part of the syslog header in RFC3164 format at
+ * the beginning of logheader once a second and return the pointer to the
+ * first character after it.
  */
-char *update_log_hdr()
+static char *update_log_hdr()
 {
 	static long tvsec;
 	static char *dataptr = NULL; /* backup of last end of header, NULL first time */
@@ -787,6 +814,43 @@ char *update_log_hdr()
 	return dataptr;
 }
 
+/* Re-generate time-based part of the syslog header in RFC5424 format at
+ * the beginning of logheader_rfc5424 once a second and return the pointer
+ * to the first character after it.
+ */
+static char *update_log_hdr_rfc5424()
+{
+	static long tvsec;
+	static char *dataptr = NULL; /* backup of last end of header, NULL first time */
+
+	if (unlikely(date.tv_sec != tvsec || dataptr == NULL)) {
+		/* this string is rebuild only once a second */
+		struct tm tm;
+		int hdr_len;
+
+		tvsec = date.tv_sec;
+		get_localtime(tvsec, &tm);
+
+		hdr_len = snprintf(logheader_rfc5424, global.max_syslog_len,
+				   "<<<<>1 %4d-%02d-%02dT%02d:%02d:%02d%s ",
+				   tm.tm_year+1900, tm.tm_mon+1, tm.tm_mday,
+				   tm.tm_hour, tm.tm_min, tm.tm_sec,
+				   localtimezone);
+		/* WARNING: depending upon implementations, snprintf may return
+		 * either -1 or the number of bytes that would be needed to store
+		 * the total message. In both cases, we must adjust it.
+		 */
+		if (hdr_len < 0 || hdr_len > global.max_syslog_len)
+			hdr_len = global.max_syslog_len;
+
+		dataptr = logheader_rfc5424 + hdr_len;
+	}
+
+	dataptr[0] = 0; // ensure we get rid of any previous attempt
+
+	return dataptr;
+}
+
 /*
  * This function sends the syslog message using a printf format string. It
  * expects an LF-terminated message.
@@ -828,8 +892,9 @@ void __send_log(struct proxy *p, int level, char *message, size_t size)
 	struct logsrv *tmp = NULL;
 	int nblogger;
 	char *log_ptr;
-	char *hdr_ptr;
+	char *hdr, *hdr_ptr;
 	size_t hdr_size;
+	struct chunk *htp;
 
 	dataptr = message;
 
@@ -846,9 +911,6 @@ void __send_log(struct proxy *p, int level, char *message, size_t size)
 	if (!logsrvs)
 		return;
 
-	hdr_ptr = update_log_hdr();
-	hdr_size = hdr_ptr - logheader;
-
 	/* Send log messages to syslog server. */
 	nblogger = 0;
 	list_for_each_entry(tmp, logsrvs, list) {
@@ -883,6 +945,25 @@ void __send_log(struct proxy *p, int level, char *message, size_t size)
 			shutdown(*plogfd, SHUT_RD);
 		}
 
+		switch (logsrv->format) {
+		case LOG_FORMAT_RFC3164:
+			hdr = logheader;
+			hdr_ptr = update_log_hdr();
+			htp = &p->log_htp;
+			break;
+
+		case LOG_FORMAT_RFC5424:
+			hdr = logheader_rfc5424;
+			hdr_ptr = update_log_hdr_rfc5424();
+			htp = &p->log_htp_rfc5424;
+			break;
+
+		default:
+			continue; /* must never happen */
+		}
+
+		hdr_size = hdr_ptr - hdr;
+
 		/* For each target, we may have a different facility.
 		 * We can also have a different log level for each message.
 		 * This induces variations in the message header length.
@@ -891,17 +972,17 @@ void __send_log(struct proxy *p, int level, char *message, size_t size)
 		 * and we change the pointer to the header accordingly.
 		 */
 		fac_level = (logsrv->facility << 3) + MAX(level, logsrv->minlvl);
-		hdr_ptr = logheader + 3; /* last digit of the log level */
+		hdr_ptr = hdr + 3; /* last digit of the log level */
 		do {
 			*hdr_ptr = '0' + fac_level % 10;
 			fac_level /= 10;
 			hdr_ptr--;
-		} while (fac_level && hdr_ptr > logheader);
+		} while (fac_level && hdr_ptr > hdr);
 		*hdr_ptr = '<';
 
 		log_ptr = dataptr;
 
-		hdr_max = hdr_size - (hdr_ptr - logheader);
+		hdr_max = hdr_size - (hdr_ptr - hdr);
 
 		if (unlikely(hdr_size >= logsrv->maxlen)) {
 			hdr_max = MIN(hdr_max, logsrv->maxlen) - 1;
@@ -909,7 +990,7 @@ void __send_log(struct proxy *p, int level, char *message, size_t size)
 		}
 
 		maxlen = logsrv->maxlen - hdr_max;
-		htp_max = p->log_htp.len;
+		htp_max = htp->len;
 
 		if (unlikely(htp_max >= maxlen)) {
 			htp_max = maxlen - 1;
@@ -930,7 +1011,7 @@ send:
 
 		iovec[0].iov_base = hdr_ptr;
 		iovec[0].iov_len = hdr_max;
-		iovec[1].iov_base = p->log_htp.str;
+		iovec[1].iov_base = htp->str;
 		iovec[1].iov_len = htp_max;
 		iovec[2].iov_base = dataptr;
 		iovec[2].iov_len = max;