Adding upstream version 2.9.5.upstream/2.9.5

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

16 files changed, 1478 insertions, 0 deletions

diff --git a/addons/ot/include/cli.h b/addons/ot/include/cli.h
new file mode 100644
index 0000000..80ed6e8
--- /dev/null
+++ b/addons/ot/include/cli.h
@@ -0,0 +1,50 @@
+/***
+ * Copyright 2020 HAProxy Technologies
+ *
+ * This file is part of the HAProxy OpenTracing filter.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
+ */
+#ifndef _OPENTRACING_CLI_H_
+#define _OPENTRACING_CLI_H_
+
+#define FLT_OT_CLI_CMD                 "flt-ot"
+
+#define FLT_OT_CLI_LOGGING_OFF         "off"
+#define FLT_OT_CLI_LOGGING_ON          "on"
+#define FLT_OT_CLI_LOGGING_NOLOGNORM   "dontlog-normal"
+#define FLT_OT_CLI_LOGGING_STATE(a)    ((a) & FLT_OT_LOGGING_ON) ? (((a) & FLT_OT_LOGGING_NOLOGNORM) ? "enabled, " FLT_OT_CLI_LOGGING_NOLOGNORM : "enabled") : "disabled"
+
+#define FLT_OT_CLI_MSG_CAT(a)          ((a) == NULL) ? "" : (a), ((a) == NULL) ? "" : "\n"
+
+enum FLT_OT_LOGGING_enum {
+	FLT_OT_LOGGING_OFF       = 0,
+	FLT_OT_LOGGING_ON        = 1 << 0,
+	FLT_OT_LOGGING_NOLOGNORM = 1 << 1,
+};
+
+
+void flt_ot_cli_init(void);
+
+#endif /* _OPENTRACING_CLI_H_ */
+
+/*
+ * Local variables:
+ *  c-indent-level: 8
+ *  c-basic-offset: 8
+ * End:
+ *
+ * vi: noexpandtab shiftwidth=8 tabstop=8
+ */
diff --git a/addons/ot/include/conf.h b/addons/ot/include/conf.h
new file mode 100644
index 0000000..c9c4863
--- /dev/null
+++ b/addons/ot/include/conf.h
@@ -0,0 +1,228 @@
+/***
+ * Copyright 2020 HAProxy Technologies
+ *
+ * This file is part of the HAProxy OpenTracing filter.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
+ */
+#ifndef _OPENTRACING_CONF_H_
+#define _OPENTRACING_CONF_H_
+
+#define FLT_OT_CONF(f)              ((struct flt_ot_conf *)FLT_CONF(f))
+#define FLT_OT_CONF_HDR_FMT         "%p:{ { '%.*s' %zu %d } "
+#define FLT_OT_CONF_HDR_ARGS(a,b)   (a), (int)(a)->b##_len, (a)->b, (a)->b##_len, (a)->cfg_line
+#define FLT_OT_STR_HDR_ARGS(a,b)    (a)->b, (a)->b##_len
+
+#define FLT_OT_DBG_CONF_SAMPLE_EXPR(f,a) \
+	FLT_OT_DBG(3, "%s%p:{ '%s' %p }", (f), (a), (a)->value, (a)->expr)
+
+#define FLT_OT_DBG_CONF_SAMPLE(f,a)               \
+	FLT_OT_DBG(3, "%s%p:{ '%s' '%s' %s %d }", \
+	           (f), (a), (a)->key, (a)->value, flt_ot_list_debug(&((a)->exprs)), (a)->num_exprs)
+
+#define FLT_OT_DBG_CONF_STR(f,a) \
+	FLT_OT_DBG(3, f FLT_OT_CONF_HDR_FMT "}", FLT_OT_CONF_HDR_ARGS(a, str))
+
+#define FLT_OT_DBG_CONF_CONTEXT(f,a) \
+	FLT_OT_DBG(3, f FLT_OT_CONF_HDR_FMT "0x%02hhx }", FLT_OT_CONF_HDR_ARGS(a, id), (a)->flags)
+
+#define FLT_OT_DBG_CONF_SPAN(f,a)                                                                                   \
+	FLT_OT_DBG(3, f FLT_OT_CONF_HDR_FMT "'%s' %zu %d '%s' %zu %hhu 0x%02hhx %s %s %s }",                        \
+	           FLT_OT_CONF_HDR_ARGS(a, id), FLT_OT_STR_HDR_ARGS(a, ref_id), (a)->ref_type,                      \
+	           FLT_OT_STR_HDR_ARGS(a, ctx_id), (a)->flag_root, (a)->ctx_flags, flt_ot_list_debug(&((a)->tags)), \
+	           flt_ot_list_debug(&((a)->logs)), flt_ot_list_debug(&((a)->baggages)))
+
+#define FLT_OT_DBG_CONF_SCOPE(f,a)                                                                           \
+	FLT_OT_DBG(3, f FLT_OT_CONF_HDR_FMT "%hhu %d %s %p %s %s %s }",                                      \
+	           FLT_OT_CONF_HDR_ARGS(a, id), (a)->flag_used, (a)->event, flt_ot_list_debug(&((a)->acls)), \
+	           (a)->cond, flt_ot_list_debug(&((a)->contexts)), flt_ot_list_debug(&((a)->spans)),         \
+	           flt_ot_list_debug(&((a)->finish)))
+
+#define FLT_OT_DBG_CONF_GROUP(f,a)                       \
+	FLT_OT_DBG(3, f FLT_OT_CONF_HDR_FMT "%hhu %s }", \
+	           FLT_OT_CONF_HDR_ARGS(a, id), (a)->flag_used, flt_ot_list_debug(&((a)->ph_scopes)))
+
+#define FLT_OT_DBG_CONF_PH(f,a) \
+	FLT_OT_DBG(3, f FLT_OT_CONF_HDR_FMT "%p }", FLT_OT_CONF_HDR_ARGS(a, id), (a)->ptr)
+
+#define FLT_OT_DBG_CONF_TRACER(f,a)                                                                                                     \
+	FLT_OT_DBG(3, f FLT_OT_CONF_HDR_FMT "'%s' %p '%s' %p %u %hhu %hhu 0x%02hhx %p:%s 0x%08x %s %s %s }",                            \
+	           FLT_OT_CONF_HDR_ARGS(a, id), (a)->config, (a)->cfgbuf, (a)->plugin, (a)->tracer, (a)->rate_limit, (a)->flag_harderr, \
+	           (a)->flag_disabled, (a)->logging, &((a)->proxy_log), flt_ot_list_debug(&((a)->proxy_log.loggers)), (a)->analyzers,   \
+	           flt_ot_list_debug(&((a)->acls)), flt_ot_list_debug(&((a)->ph_groups)), flt_ot_list_debug(&((a)->ph_scopes)))
+
+#define FLT_OT_DBG_CONF(f,a)                                                  \
+	FLT_OT_DBG(3, "%s%p:{ %p '%s' '%s' %p %s %s }",                       \
+	           (f), (a), (a)->proxy, (a)->id, (a)->cfg_file, (a)->tracer, \
+	           flt_ot_list_debug(&((a)->groups)), flt_ot_list_debug(&((a)->scopes)))
+
+#define FLT_OT_STR_HDR(a)        \
+	struct {                 \
+		char   *a;       \
+		size_t  a##_len; \
+	}
+
+#define FLT_OT_CONF_HDR(a)            \
+	struct {                      \
+		FLT_OT_STR_HDR(a);    \
+		int         cfg_line; \
+		struct list list;     \
+	}
+
+
+struct flt_ot_conf_hdr {
+	FLT_OT_CONF_HDR(id);
+};
+
+/* flt_ot_conf_sample->exprs */
+struct flt_ot_conf_sample_expr {
+	FLT_OT_CONF_HDR(value);   /* The sample value. */
+	struct sample_expr *expr; /* The sample expression. */
+};
+
+/*
+ * flt_ot_conf_span->tags
+ * flt_ot_conf_span->logs
+ * flt_ot_conf_span->baggages
+ */
+struct flt_ot_conf_sample {
+	FLT_OT_CONF_HDR(key);   /* The sample name. */
+	char        *value;     /* The sample content. */
+	struct list  exprs;     /* Used to chain sample expressions. */
+	int          num_exprs; /* Number of defined expressions. */
+};
+
+/* flt_ot_conf_scope->finish */
+struct flt_ot_conf_str {
+	FLT_OT_CONF_HDR(str); /* String content/length. */
+};
+
+/* flt_ot_conf_scope->contexts */
+struct flt_ot_conf_context {
+	FLT_OT_CONF_HDR(id); /* The name of the context. */
+	uint8_t flags;       /* The type of storage from which the span context is extracted.  */
+};
+
+/* flt_ot_conf_scope->spans */
+struct flt_ot_conf_span {
+	FLT_OT_CONF_HDR(id);    /* The name of the span. */
+	FLT_OT_STR_HDR(ref_id); /* The reference name, if used. */
+	int         ref_type;   /* The reference type. */
+	FLT_OT_STR_HDR(ctx_id); /* The span context name, if used. */
+	uint8_t     ctx_flags;  /* The type of storage used for the span context. */
+	bool        flag_root;  /* Whether this is a root span. */
+	struct list tags;       /* The set of key:value tags. */
+	struct list logs;       /* The set of key:value logs. */
+	struct list baggages;   /* The set of key:value baggage items. */
+};
+
+struct flt_ot_conf_scope {
+	FLT_OT_CONF_HDR(id);        /* The scope name. */
+	bool             flag_used; /* The indication that the scope is being used. */
+	int              event;     /* FLT_OT_EVENT_* */
+	struct list      acls;      /* ACLs declared on this scope. */
+	struct acl_cond *cond;      /* ACL condition to meet. */
+	struct list      contexts;  /* Declared contexts. */
+	struct list      spans;     /* Declared spans. */
+	struct list      finish;    /* The list of spans to be finished. */
+};
+
+struct flt_ot_conf_group {
+	FLT_OT_CONF_HDR(id);   /* The group name. */
+	bool        flag_used; /* The indication that the group is being used. */
+	struct list ph_scopes; /* List of all used scopes. */
+};
+
+struct flt_ot_conf_ph {
+	FLT_OT_CONF_HDR(id); /* The scope/group name. */
+	void *ptr;           /* Pointer to real placeholder structure. */
+};
+#define flt_ot_conf_ph_group      flt_ot_conf_ph
+#define flt_ot_conf_ph_scope      flt_ot_conf_ph
+
+struct flt_ot_conf_tracer {
+	FLT_OT_CONF_HDR(id);              /* The tracer name. */
+	char              *config;        /* The OpenTracing configuration file name. */
+	char              *cfgbuf;        /* The OpenTracing configuration. */
+	char              *plugin;        /* The OpenTracing plugin library file name. */
+	struct otc_tracer *tracer;        /* The OpenTracing tracer handle. */
+	uint32_t           rate_limit;    /* [0 2^32-1] <-> [0.0 100.0] */
+	bool               flag_harderr;  /* [0 1] */
+	bool               flag_disabled; /* [0 1] */
+	uint8_t            logging;       /* [0 1 3] */
+	struct proxy       proxy_log;     /* The log server list. */
+	uint               analyzers;     /* Defined channel analyzers. */
+	struct list        acls;          /* ACLs declared on this tracer. */
+	struct list        ph_groups;     /* List of all used groups. */
+	struct list        ph_scopes;     /* List of all used scopes. */
+};
+
+struct flt_ot_counters {
+#ifdef DEBUG_OT
+	struct {
+		bool     flag_used; /* Whether this event is used. */
+		uint64_t htx[2];    /* htx_is_empty() function result counter. */
+	} event[FLT_OT_EVENT_MAX];
+#endif
+
+	uint64_t disabled[2];       /* How many times stream processing is disabled. */
+};
+
+/* The OpenTracing filter configuration. */
+struct flt_ot_conf {
+	struct proxy              *proxy;    /* Proxy owning the filter. */
+	char                      *id;       /* The OpenTracing filter id. */
+	char                      *cfg_file; /* The OpenTracing filter configuration file name. */
+	struct flt_ot_conf_tracer *tracer;   /* There can only be one tracer. */
+	struct list                groups;   /* List of all available groups. */
+	struct list                scopes;   /* List of all available scopes. */
+	struct flt_ot_counters     cnt;      /* Various counters related to filter operation. */
+};
+
+
+#define flt_ot_conf_ph_group_free   flt_ot_conf_ph_free
+#define flt_ot_conf_ph_scope_free   flt_ot_conf_ph_free
+
+struct flt_ot_conf_ph          *flt_ot_conf_ph_init(const char *id, int linenum, struct list *head, char **err);
+void                            flt_ot_conf_ph_free(struct flt_ot_conf_ph **ptr);
+struct flt_ot_conf_sample_expr *flt_ot_conf_sample_expr_init(const char *id, int linenum, struct list *head, char **err);
+void                            flt_ot_conf_sample_expr_free(struct flt_ot_conf_sample_expr **ptr);
+struct flt_ot_conf_sample      *flt_ot_conf_sample_init(char **args, int linenum, struct list *head, char **err);
+void                            flt_ot_conf_sample_free(struct flt_ot_conf_sample **ptr);
+struct flt_ot_conf_str         *flt_ot_conf_str_init(const char *id, int linenum, struct list *head, char **err);
+void                            flt_ot_conf_str_free(struct flt_ot_conf_str **ptr);
+struct flt_ot_conf_context     *flt_ot_conf_context_init(const char *id, int linenum, struct list *head, char **err);
+void                            flt_ot_conf_context_free(struct flt_ot_conf_context **ptr);
+struct flt_ot_conf_span        *flt_ot_conf_span_init(const char *id, int linenum, struct list *head, char **err);
+void                            flt_ot_conf_span_free(struct flt_ot_conf_span **ptr);
+struct flt_ot_conf_scope       *flt_ot_conf_scope_init(const char *id, int linenum, struct list *head, char **err);
+void                            flt_ot_conf_scope_free(struct flt_ot_conf_scope **ptr);
+struct flt_ot_conf_group       *flt_ot_conf_group_init(const char *id, int linenum, struct list *head, char **err);
+void                            flt_ot_conf_group_free(struct flt_ot_conf_group **ptr);
+struct flt_ot_conf_tracer      *flt_ot_conf_tracer_init(const char *id, int linenum, char **err);
+void                            flt_ot_conf_tracer_free(struct flt_ot_conf_tracer **ptr);
+struct flt_ot_conf             *flt_ot_conf_init(struct proxy *px);
+void                            flt_ot_conf_free(struct flt_ot_conf **ptr);
+
+#endif /* _OPENTRACING_CONF_H_ */
+
+/*
+ * Local variables:
+ *  c-indent-level: 8
+ *  c-basic-offset: 8
+ * End:
+ *
+ * vi: noexpandtab shiftwidth=8 tabstop=8
+ */
diff --git a/addons/ot/include/config.h b/addons/ot/include/config.h
new file mode 100644
index 0000000..3b26365
--- /dev/null
+++ b/addons/ot/include/config.h
@@ -0,0 +1,46 @@
+/***
+ * Copyright 2020 HAProxy Technologies
+ *
+ * This file is part of the HAProxy OpenTracing filter.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
+ */
+#ifndef _OPENTRACING_CONFIG_H_
+#define _OPENTRACING_CONFIG_H_
+
+#undef  DEBUG_OT_SYSTIME
+#define USE_POOL_BUFFER
+#define USE_POOL_OT_SPAN_CONTEXT
+#define USE_POOL_OT_SCOPE_SPAN
+#define USE_POOL_OT_SCOPE_CONTEXT
+#define USE_POOL_OT_RUNTIME_CONTEXT
+#define USE_TRASH_CHUNK
+
+#define FLT_OT_ID_MAXLEN        64
+#define FLT_OT_MAXTAGS          8
+#define FLT_OT_MAXBAGGAGES      8
+#define FLT_OT_RATE_LIMIT_MAX   100.0
+#define FLT_OT_DEBUG_LEVEL      0b00001111
+
+#endif /* _OPENTRACING_CONFIG_H_ */
+
+/*
+ * Local variables:
+ *  c-indent-level: 8
+ *  c-basic-offset: 8
+ * End:
+ *
+ * vi: noexpandtab shiftwidth=8 tabstop=8
+ */
diff --git a/addons/ot/include/debug.h b/addons/ot/include/debug.h
new file mode 100644
index 0000000..c749960
--- /dev/null
+++ b/addons/ot/include/debug.h
@@ -0,0 +1,104 @@
+/***
+ * Copyright 2020 HAProxy Technologies
+ *
+ * This file is part of the HAProxy OpenTracing filter.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
+ */
+#ifndef _OPENTRACING_DEBUG_H_
+#define _OPENTRACING_DEBUG_H_
+
+#ifdef DEBUG_FULL
+#  define DEBUG_OT
+#endif
+
+#ifdef DEBUG_OT
+#  ifdef DEBUG_OT_SYSTIME
+#     define FLT_OT_DBG_FMT(f)      "[% 2d] %ld.%06ld [" FLT_OT_SCOPE "]: " f, tid, date.tv_sec, date.tv_usec
+#  else
+#     define FLT_OT_DBG_FMT(f)      "[% 2d] %11.6f [" FLT_OT_SCOPE "]: " f, tid, FLT_OT_TV_UDIFF(&(flt_ot_debug.start), &date) / 1e6
+#  endif
+#  define FLT_OT_DBG_INDENT         "                                                                                "
+#  define FLT_OT_DBG(l,f, ...)                                                             \
+	do {                                                                               \
+		if (!(l) || (flt_ot_debug.level & (1 << (l))))                             \
+			(void)fprintf(stderr, FLT_OT_DBG_FMT("%.*s" f "\n"),               \
+			              dbg_indent_level, FLT_OT_DBG_INDENT, ##__VA_ARGS__); \
+	} while (0)
+#  define FLT_OT_FUNC(f, ...)       do { FLT_OT_DBG(1, "%s(" f ") {", __func__, ##__VA_ARGS__); dbg_indent_level += 3; } while (0)
+#  define FLT_OT_RETURN(a)          do { dbg_indent_level -= 3; FLT_OT_DBG(1, "}"); return a; } while (0)
+#  define FLT_OT_RETURN_EX(a,t,f)   do { dbg_indent_level -= 3; { t _r = (a); FLT_OT_DBG(1, "} = " f, _r); return _r; } } while (0)
+#  define FLT_OT_RETURN_INT(a)      FLT_OT_RETURN_EX((a), int, "%d")
+#  define FLT_OT_RETURN_PTR(a)      FLT_OT_RETURN_EX((a), void *, "%p")
+#  define FLT_OT_DBG_IFDEF(a,b)     a
+#  define FLT_OT_DBG_ARGS(a, ...)   a, ##__VA_ARGS__
+#  define FLT_OT_DBG_BUF(a,b)       do { FLT_OT_DBG((a), "%p:{ %zu %p %zu %zu }", (b), (b)->size, (b)->area, (b)->data, (b)->head); } while (0)
+
+struct flt_ot_debug {
+#ifndef DEBUG_OT_SYSTIME
+	struct timeval start;
+#endif
+	uint8_t        level;
+};
+
+
+extern THREAD_LOCAL int    dbg_indent_level;
+extern struct flt_ot_debug flt_ot_debug;
+
+#else
+
+#  define FLT_OT_DBG(...)           while (0)
+#  define FLT_OT_FUNC(...)          while (0)
+#  define FLT_OT_RETURN(a)          return a
+#  define FLT_OT_RETURN_EX(a,t,f)   return a
+#  define FLT_OT_RETURN_INT(a)      return a
+#  define FLT_OT_RETURN_PTR(a)      return a
+#  define FLT_OT_DBG_IFDEF(a,b)     b
+#  define FLT_OT_DBG_ARGS(...)
+#  define FLT_OT_DBG_BUF(a,b)       while (0)
+#endif /* DEBUG_OT */
+
+/*
+ *  ON  | NOLOGNORM |
+ * -----+-----------+-------------
+ *   0  |     0     |  no log
+ *   0  |     1     |  no log
+ *   1  |     0     |  log all
+ *   1  |     1     |  log errors
+ * -----+-----------+-------------
+ */
+#define FLT_OT_LOG(l,f, ...)                                                                                                    \
+	do {                                                                                                                    \
+		if (!(conf->tracer->logging & FLT_OT_LOGGING_ON))                                                               \
+			FLT_OT_DBG(3, "NOLOG[%d]: [" FLT_OT_SCOPE "]: [%s] " f, (l), conf->id, ##__VA_ARGS__);                  \
+		else if ((conf->tracer->logging & FLT_OT_LOGGING_NOLOGNORM) && ((l) > LOG_ERR))                                 \
+			FLT_OT_DBG(2, "NOLOG[%d]: [" FLT_OT_SCOPE "]: [%s] " f, (l), conf->id, ##__VA_ARGS__);                  \
+		else {                                                                                                          \
+			send_log(&(conf->tracer->proxy_log), (l), "[" FLT_OT_SCOPE "]: [%s] " f "\n", conf->id, ##__VA_ARGS__); \
+                                                                                                                                \
+			FLT_OT_DBG(1, "LOG[%d]: %s", (l), logline);                                                             \
+		}                                                                                                               \
+	} while (0)
+
+#endif /* _OPENTRACING_DEBUG_H_ */
+
+/*
+ * Local variables:
+ *  c-indent-level: 8
+ *  c-basic-offset: 8
+ * End:
+ *
+ * vi: noexpandtab shiftwidth=8 tabstop=8
+ */
diff --git a/addons/ot/include/define.h b/addons/ot/include/define.h
new file mode 100644
index 0000000..3c3e4a3
--- /dev/null
+++ b/addons/ot/include/define.h
@@ -0,0 +1,107 @@
+/***
+ * Copyright 2020 HAProxy Technologies
+ *
+ * This file is part of the HAProxy OpenTracing filter.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
+ */
+#ifndef _OPENTRACING_DEFINE_H_
+#define _OPENTRACING_DEFINE_H_
+
+#define FLT_OT_DEREF(a,m,v)        (((a) != NULL) ? (a)->m : (v))
+#define FLT_OT_DDEREF(a,m,v)       ((((a) != NULL) && (*(a) != NULL)) ? (*(a))->m : (v))
+#define FLT_OT_TABLESIZE(a)        (sizeof(a) / sizeof((a)[0]))
+#define FLT_OT_IN_RANGE(v,a,b)     (((v) >= (a)) && ((v) <= (b)))
+#define FLT_OT_DPTR_ARGS(a)        (a), ((a) == NULL) ? NULL : *(a)
+#define FLT_OT_ARG_ISVALID(n)      ((args[n] != NULL) && *args[n])
+#define FLT_OT_TV_UDIFF(a,b)       (((b)->tv_sec - (a)->tv_sec) * 1000000 + (b)->tv_usec - (a)->tv_usec)
+#define FLT_OT_U32_FLOAT(a,b)      ((a) * (double)(b) / UINT32_MAX)
+#define FLT_OT_FLOAT_U32(a,b)      ((uint32_t)((a) / (double)(b) * UINT32_MAX + 0.5))
+
+#define FLT_OT_STR_DASH_72         "------------------------------------------------------------------------"
+#define FLT_OT_STR_DASH_78         FLT_OT_STR_DASH_72 "------"
+#define FLT_OT_STR_FLAG_YN(a)      (a) ? "yes" : "no"
+
+#define FLT_OT_STR_SIZE(a)         (sizeof(a) - 1)
+#define FLT_OT_STR_ADDRSIZE(a)     (a), FLT_OT_STR_SIZE(a)
+#define FLT_OT_STR_ISVALID(a)      (((a) != NULL) && (*(a) != '\0'))
+#define FLT_OT_STR_CMP(S,s,l)      (((l) == FLT_OT_STR_SIZE(S)) && (memcmp((s), FLT_OT_STR_ADDRSIZE(S)) == 0))
+#define FLT_OT_STR_ELLIPSIS(a,n)   do { if ((a) != NULL) { if ((n) > 0) (a)[(n) - 1] = '\0'; if ((n) > 3) (a)[(n) - 2] = (a)[(n) - 3] = (a)[(n) - 4] = '.'; } } while (0)
+#define FLT_OT_NIBBLE_TO_HEX(a)    ((a) + (((a) < 10) ? '0' : ('a' - 10)))
+
+#define FLT_OT_FREE(a)             do { if ((a) != NULL) OTC_DBG_FREE(a); } while (0)
+#define FLT_OT_FREE_VOID(a)        do { if ((a) != NULL) OTC_DBG_FREE((void *)(a)); } while (0)
+#define FLT_OT_FREE_CLEAR(a)       do { if ((a) != NULL) { OTC_DBG_FREE(a); (a) = NULL; } } while (0)
+#define FLT_OT_STRDUP(s)           OTC_DBG_STRDUP(s)
+#define FLT_OT_STRNDUP(s,n)        OTC_DBG_STRNDUP((s), (n))
+#define FLT_OT_CALLOC(n,e)         OTC_DBG_CALLOC((n), (e))
+#define FLT_OT_MALLOC(s)           OTC_DBG_MALLOC((s))
+#define FLT_OT_MEMINFO()           OTC_DBG_MEMINFO()
+
+#define FLT_OT_RUN_ONCE(f)         do { static bool __f = 1; if (__f) { __f = 0; f; } } while (0)
+
+#define FLT_OT_LIST_ISVALID(a)     (((a) != NULL) && ((a)->n != NULL) && ((a)->p != NULL))
+#define FLT_OT_LIST_DEL(a)         do { if (FLT_OT_LIST_ISVALID(a)) LIST_DELETE(a); } while (0)
+#define FLT_OT_LIST_DESTROY(t,h)                                                  \
+	do {                                                                      \
+		struct flt_ot_conf_##t *_ptr, *_back;                             \
+                                                                                  \
+		if (!FLT_OT_LIST_ISVALID(h) || LIST_ISEMPTY(h))                   \
+			break;                                                    \
+                                                                                  \
+		FLT_OT_DBG(2, "- deleting " #t " list %s", flt_ot_list_debug(h)); \
+                                                                                  \
+		list_for_each_entry_safe(_ptr, _back, (h), list)                  \
+			flt_ot_conf_##t##_free(&_ptr);                            \
+	} while (0)
+
+#define FLT_OT_BUFFER_THR(b,m,n,p)                \
+	static THREAD_LOCAL char    b[m][n];      \
+	static THREAD_LOCAL size_t  __idx = 0;    \
+	char                       *p = b[__idx]; \
+	__idx = (__idx + 1) % (m)
+
+#define FLT_OT_ERR(f, ...)                                             \
+	do {                                                           \
+		if ((err != NULL) && (*err == NULL)) {                 \
+			(void)memprintf(err, f, ##__VA_ARGS__);        \
+                                                                       \
+			FLT_OT_DBG(3, "%d err: '%s'", __LINE__, *err); \
+		}                                                      \
+	} while (0)
+#define FLT_OT_ERR_APPEND(f, ...)                               \
+	do {                                                    \
+		if (err != NULL)                                \
+			(void)memprintf(err, f, ##__VA_ARGS__); \
+	} while (0)
+#define FLT_OT_ERR_FREE(p)                                                  \
+	do {                                                                \
+		if ((p) == NULL)                                            \
+			break;                                              \
+                                                                            \
+		FLT_OT_DBG(0, "%s:%d: ERROR: %s", __func__, __LINE__, (p)); \
+		FLT_OT_FREE_CLEAR(p);                                       \
+	} while (0)
+
+#endif /* _OPENTRACING_DEFINE_H_ */
+
+/*
+ * Local variables:
+ *  c-indent-level: 8
+ *  c-basic-offset: 8
+ * End:
+ *
+ * vi: noexpandtab shiftwidth=8 tabstop=8
+ */
diff --git a/addons/ot/include/event.h b/addons/ot/include/event.h
new file mode 100644
index 0000000..8d59163
--- /dev/null
+++ b/addons/ot/include/event.h
@@ -0,0 +1,120 @@
+/***
+ * Copyright 2020 HAProxy Technologies
+ *
+ * This file is part of the HAProxy OpenTracing filter.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
+ */
+#ifndef _OPENTRACING_EVENT_H_
+#define _OPENTRACING_EVENT_H_
+
+/*
+ * This must be defined in order for macro FLT_OT_EVENT_DEFINES
+ * and structure flt_ot_event_data to have the correct contents.
+ */
+#define AN_REQ_NONE                 0
+#define AN_REQ_CLIENT_SESS_START    0
+#define AN_REQ_SERVER_UNAVAILABLE   0
+#define AN_REQ_CLIENT_SESS_END      0
+#define AN_RES_SERVER_SESS_START    0
+#define AN_RES_SERVER_SESS_END      0
+#define SMP_VAL_FE_                 0
+#define SMP_VAL_BE_                 0
+
+/*
+ * Event names are selected to be somewhat compatible with the SPOE filter,
+ * from which the following names are taken:
+ *   - on-client-session -> on-client-session-start
+ *   - on-frontend-tcp-request
+ *   - on-frontend-http-request
+ *   - on-backend-tcp-request
+ *   - on-backend-http-request
+ *   - on-server-session -> on-server-session-start
+ *   - on-tcp-response
+ *   - on-http-response
+ *
+ * FLT_OT_EVENT_NONE is used as an index for 'ot-scope' sections that do not
+ * have an event defined.  The 'ot-scope' sections thus defined can be used
+ * within the 'ot-group' section.
+ *
+ * A description of the macro arguments can be found in the structure
+ * flt_ot_event_data definition
+ */
+#define FLT_OT_EVENT_DEFINES                                                                                \
+	FLT_OT_EVENT_DEF(              NONE, REQ,        ,        , 0, "")                                  \
+	FLT_OT_EVENT_DEF( CLIENT_SESS_START, REQ, CON_ACC,        , 1, "on-client-session-start")           \
+	FLT_OT_EVENT_DEF(        INSPECT_FE, REQ, REQ_CNT,        , 1, "on-frontend-tcp-request")           \
+	FLT_OT_EVENT_DEF(         WAIT_HTTP, REQ,        ,        , 1, "on-http-wait-request")              \
+	FLT_OT_EVENT_DEF(         HTTP_BODY, REQ,        ,        , 1, "on-http-body-request")              \
+	FLT_OT_EVENT_DEF(   HTTP_PROCESS_FE, REQ, HRQ_HDR,        , 1, "on-frontend-http-request")          \
+	FLT_OT_EVENT_DEF(   SWITCHING_RULES, REQ,        ,        , 1, "on-switching-rules-request")        \
+	FLT_OT_EVENT_DEF(        INSPECT_BE, REQ, REQ_CNT, REQ_CNT, 1, "on-backend-tcp-request")            \
+	FLT_OT_EVENT_DEF(   HTTP_PROCESS_BE, REQ, HRQ_HDR, HRQ_HDR, 1, "on-backend-http-request")           \
+/*	FLT_OT_EVENT_DEF(       HTTP_TARPIT, REQ,        ,        , 1, "on-http-tarpit-request") */         \
+	FLT_OT_EVENT_DEF(         SRV_RULES, REQ,        ,        , 1, "on-process-server-rules-request")   \
+	FLT_OT_EVENT_DEF(        HTTP_INNER, REQ,        ,        , 1, "on-http-process-request")           \
+	FLT_OT_EVENT_DEF(   PRST_RDP_COOKIE, REQ,        ,        , 1, "on-tcp-rdp-cookie-request")         \
+	FLT_OT_EVENT_DEF(    STICKING_RULES, REQ,        ,        , 1, "on-process-sticking-rules-request") \
+	FLT_OT_EVENT_DEF(   CLIENT_SESS_END, REQ,        ,        , 0, "on-client-session-end")             \
+	FLT_OT_EVENT_DEF(SERVER_UNAVAILABLE, REQ,        ,        , 0, "on-server-unavailable")             \
+                                                                                                            \
+	FLT_OT_EVENT_DEF( SERVER_SESS_START, RES,        , SRV_CON, 0, "on-server-session-start")           \
+	FLT_OT_EVENT_DEF(           INSPECT, RES, RES_CNT, RES_CNT, 0, "on-tcp-response")                   \
+	FLT_OT_EVENT_DEF(         WAIT_HTTP, RES,        ,        , 1, "on-http-wait-response")             \
+	FLT_OT_EVENT_DEF(       STORE_RULES, RES,        ,        , 1, "on-process-store-rules-response")   \
+	FLT_OT_EVENT_DEF(   HTTP_PROCESS_BE, RES, HRS_HDR, HRS_HDR, 1, "on-http-response")                  \
+	FLT_OT_EVENT_DEF(   SERVER_SESS_END, RES,        ,        , 0, "on-server-session-end")
+
+enum FLT_OT_EVENT_enum {
+#define FLT_OT_EVENT_DEF(a,b,c,d,e,f)   FLT_OT_EVENT_##b##_##a,
+	FLT_OT_EVENT_DEFINES
+	FLT_OT_EVENT_MAX
+#undef FLT_OT_EVENT_DEF
+};
+
+enum FLT_OT_EVENT_SAMPLE_enum {
+	FLT_OT_EVENT_SAMPLE_TAG = 0,
+	FLT_OT_EVENT_SAMPLE_LOG,
+	FLT_OT_EVENT_SAMPLE_BAGGAGE,
+};
+
+struct flt_ot_event_data {
+	uint        an_bit;           /* Used channel analyser. */
+	uint        smp_opt_dir;      /* Fetch direction (request/response). */
+	uint        smp_val_fe;       /* Valid FE fetch location. */
+	uint        smp_val_be;       /* Valid BE fetch location. */
+	bool        flag_http_inject; /* Span context injection allowed. */
+	const char *name;             /* Filter event name. */
+};
+
+struct flt_ot_conf_scope;
+
+
+extern const struct flt_ot_event_data flt_ot_event_data[FLT_OT_EVENT_MAX];
+
+
+int flt_ot_scope_run(struct stream *s, struct filter *f, struct channel *chn, struct flt_ot_conf_scope *conf_scope, const struct timespec *ts, uint dir, char **err);
+int flt_ot_event_run(struct stream *s, struct filter *f, struct channel *chn, int event, char **err);
+
+#endif /* _OPENTRACING_EVENT_H_ */
+
+/*
+ * Local variables:
+ *  c-indent-level: 8
+ *  c-basic-offset: 8
+ * End:
+ *
+ * vi: noexpandtab shiftwidth=8 tabstop=8
+ */
diff --git a/addons/ot/include/filter.h b/addons/ot/include/filter.h
new file mode 100644
index 0000000..c97a0cc
--- /dev/null
+++ b/addons/ot/include/filter.h
@@ -0,0 +1,68 @@
+/***
+ * Copyright 2020 HAProxy Technologies
+ *
+ * This file is part of the HAProxy OpenTracing filter.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
+ */
+#ifndef _OPENTRACING_FILTER_H_
+#define _OPENTRACING_FILTER_H_
+
+#define FLT_OT_FMT_NAME           "'" FLT_OT_OPT_NAME "' : "
+#define FLT_OT_FMT_TYPE           "'filter' : "
+#define FLT_OT_VAR_UUID           "sess", "ot", "uuid"
+#define FLT_OT_ALERT(f, ...)      ha_alert(FLT_OT_FMT_TYPE FLT_OT_FMT_NAME f "\n", ##__VA_ARGS__)
+
+#define FLT_OT_CONDITION_IF       "if"
+#define FLT_OT_CONDITION_UNLESS   "unless"
+
+enum FLT_OT_RET_enum {
+	FLT_OT_RET_ERROR  = -1,
+	FLT_OT_RET_WAIT   = 0,
+	FLT_OT_RET_IGNORE = 0,
+	FLT_OT_RET_OK     = 1,
+};
+
+#define FLT_OT_DBG_LIST(d,m,p,t,v,f)                                 \
+	do {                                                         \
+		if (LIST_ISEMPTY(&((d)->m##s))) {                    \
+			FLT_OT_DBG(3, p "- no " #m "s " t);          \
+		} else {                                             \
+			const struct flt_ot_conf_##m *v;             \
+                                                                     \
+			FLT_OT_DBG(3, p "- " t " " #m "s: %s",       \
+			           flt_ot_list_debug(&((d)->m##s))); \
+			list_for_each_entry(v, &((d)->m##s), list)   \
+				do { f; } while (0);                 \
+		}                                                    \
+	} while (0)
+
+
+extern const char     *ot_flt_id;
+extern struct flt_ops  flt_ot_ops;
+
+
+bool flt_ot_is_disabled(const struct filter *f FLT_OT_DBG_ARGS(, int event));
+
+#endif /* _OPENTRACING_FILTER_H_ */
+
+/*
+ * Local variables:
+ *  c-indent-level: 8
+ *  c-basic-offset: 8
+ * End:
+ *
+ * vi: noexpandtab shiftwidth=8 tabstop=8
+ */
diff --git a/addons/ot/include/group.h b/addons/ot/include/group.h
new file mode 100644
index 0000000..a9bfcc6
--- /dev/null
+++ b/addons/ot/include/group.h
@@ -0,0 +1,61 @@
+/***
+ * Copyright 2020 HAProxy Technologies
+ *
+ * This file is part of the HAProxy OpenTracing filter.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
+ */
+#ifndef _OPENTRACING_GROUP_H_
+#define _OPENTRACING_GROUP_H_
+
+#define FLT_OT_ACTION_GROUP   "ot-group"
+
+enum FLT_OT_ARG_enum {
+	FLT_OT_ARG_FILTER_ID = 0,
+	FLT_OT_ARG_GROUP_ID,
+
+	FLT_OT_ARG_FLT_CONF = 0,
+	FLT_OT_ARG_CONF,
+	FLT_OT_ARG_GROUP,
+};
+
+/*
+ * A description of the macro arguments can be found in the structure
+ * flt_ot_group_data definition
+ */
+#define FLT_OT_GROUP_DEFINES                                                     \
+	FLT_OT_GROUP_DEF(ACT_F_TCP_REQ_CON, SMP_VAL_FE_CON_ACC, SMP_OPT_DIR_REQ) \
+	FLT_OT_GROUP_DEF(ACT_F_TCP_REQ_SES, SMP_VAL_FE_SES_ACC, SMP_OPT_DIR_REQ) \
+	FLT_OT_GROUP_DEF(ACT_F_TCP_REQ_CNT, SMP_VAL_FE_REQ_CNT, SMP_OPT_DIR_REQ) \
+	FLT_OT_GROUP_DEF(ACT_F_TCP_RES_CNT, SMP_VAL_BE_RES_CNT, SMP_OPT_DIR_RES) \
+	FLT_OT_GROUP_DEF(ACT_F_HTTP_REQ,    SMP_VAL_FE_HRQ_HDR, SMP_OPT_DIR_REQ) \
+	FLT_OT_GROUP_DEF(ACT_F_HTTP_RES,    SMP_VAL_BE_HRS_HDR, SMP_OPT_DIR_RES)
+
+struct flt_ot_group_data {
+	enum act_from act_from;    /* ACT_F_* */
+	uint          smp_val;     /* Valid FE/BE fetch location. */
+	uint          smp_opt_dir; /* Fetch direction (request/response). */
+};
+
+#endif /* _OPENTRACING_GROUP_H_ */
+
+/*
+ * Local variables:
+ *  c-indent-level: 8
+ *  c-basic-offset: 8
+ * End:
+ *
+ * vi: noexpandtab shiftwidth=8 tabstop=8
+ */
diff --git a/addons/ot/include/http.h b/addons/ot/include/http.h
new file mode 100644
index 0000000..c323cde
--- /dev/null
+++ b/addons/ot/include/http.h
@@ -0,0 +1,41 @@
+/***
+ * Copyright 2020 HAProxy Technologies
+ *
+ * This file is part of the HAProxy OpenTracing filter.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
+ */
+#ifndef _OPENTRACING_HTTP_H_
+#define _OPENTRACING_HTTP_H_
+
+#ifndef DEBUG_OT
+#  define flt_ot_http_headers_dump(...)   while (0)
+#else
+void                 flt_ot_http_headers_dump(const struct channel *chn);
+#endif
+struct otc_text_map *flt_ot_http_headers_get(struct channel *chn, const char *prefix, size_t len, char **err);
+int                  flt_ot_http_header_set(struct channel *chn, const char *prefix, const char *name, const char *value, char **err);
+int                  flt_ot_http_headers_remove(struct channel *chn, const char *prefix, char **err);
+
+#endif /* _OPENTRACING_HTTP_H_ */
+
+/*
+ * Local variables:
+ *  c-indent-level: 8
+ *  c-basic-offset: 8
+ * End:
+ *
+ * vi: noexpandtab shiftwidth=8 tabstop=8
+ */
diff --git a/addons/ot/include/include.h b/addons/ot/include/include.h
new file mode 100644
index 0000000..f1a5672
--- /dev/null
+++ b/addons/ot/include/include.h
@@ -0,0 +1,66 @@
+/***
+ * Copyright 2020 HAProxy Technologies
+ *
+ * This file is part of the HAProxy OpenTracing filter.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
+ */
+#ifndef _OPENTRACING_INCLUDE_H_
+#define _OPENTRACING_INCLUDE_H_
+
+#include <errno.h>
+#include <stdbool.h>
+
+#include <haproxy/api.h>
+#include <haproxy/cfgparse.h>
+#include <haproxy/acl.h>
+#include <haproxy/cli.h>
+#include <haproxy/clock.h>
+#include <haproxy/filters.h>
+#include <haproxy/http_htx.h>
+#include <haproxy/http_rules.h>
+#include <haproxy/log.h>
+#include <haproxy/proxy.h>
+#include <haproxy/sample.h>
+#include <haproxy/tcp_rules.h>
+#include <haproxy/tools.h>
+#include <haproxy/vars.h>
+
+#include "config.h"
+#include "debug.h"
+#include "define.h"
+#include "cli.h"
+#include "event.h"
+#include "conf.h"
+#include "filter.h"
+#include "group.h"
+#include "http.h"
+#include "opentracing.h"
+#include "parser.h"
+#include "pool.h"
+#include "scope.h"
+#include "util.h"
+#include "vars.h"
+
+#endif /* _OPENTRACING_INCLUDE_H_ */
+
+/*
+ * Local variables:
+ *  c-indent-level: 8
+ *  c-basic-offset: 8
+ * End:
+ *
+ * vi: noexpandtab shiftwidth=8 tabstop=8
+ */
diff --git a/addons/ot/include/opentracing.h b/addons/ot/include/opentracing.h
new file mode 100644
index 0000000..2b88a33
--- /dev/null
+++ b/addons/ot/include/opentracing.h
@@ -0,0 +1,86 @@
+/***
+ * Copyright 2020 HAProxy Technologies
+ *
+ * This file is part of the HAProxy OpenTracing filter.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
+ */
+#ifndef _OPENTRACING_OT_H_
+#define _OPENTRACING_OT_H_
+
+#include <opentracing-c-wrapper/include.h>
+
+
+#define FLT_OT_VSET(p,t,v) \
+	do { (p)->type = otc_value_##t; (p)->value.t##_value = (v); } while (0)
+
+#define FLT_OT_DBG_TEXT_MAP(a)                     \
+	FLT_OT_DBG(3, "%p:{ %p %p %zu/%zu %hhu }", \
+	           (a), (a)->key, (a)->value, (a)->count, (a)->size, (a)->is_dynamic)
+
+#define FLT_OT_DBG_TEXT_CARRIER(a,f)                                                 \
+	FLT_OT_DBG(3, "%p:{ { %p %p %zu/%zu %hhu } %p }",                            \
+	           (a), (a)->text_map.key, (a)->text_map.value, (a)->text_map.count, \
+	           (a)->text_map.size, (a)->text_map.is_dynamic, (a)->f)
+
+#define FLT_OT_DBG_CUSTOM_CARRIER(a,f)                                \
+	FLT_OT_DBG(3, "%p:{ { %p %zu %hhu } %p }",                    \
+	           (a), (a)->binary_data.data, (a)->binary_data.size, \
+	           (a)->binary_data.is_dynamic, (a)->f)
+
+#define FLT_OT_DBG_SPAN_CONTEXT(a) \
+	FLT_OT_DBG(3, "%p:{ %" PRId64 " %p %p }", (a), (a)->idx, (a)->span, (a)->destroy)
+
+
+#ifndef DEBUG_OT
+#  define ot_debug()              while (0)
+#  define ot_text_map_show(...)   while (0)
+#else
+void                     ot_text_map_show(const struct otc_text_map *text_map);
+void                     ot_debug(void);
+#endif
+int                      ot_init(struct otc_tracer **tracer, const char *plugin, char **err);
+int                      ot_start(struct otc_tracer *tracer, const char *cfgbuf, char **err);
+struct otc_span         *ot_span_init(struct otc_tracer *tracer, const char *operation_name, const struct timespec *ts_steady, const struct timespec *ts_system, int ref_type, int ref_ctx_idx, const struct otc_span *ref_span, const struct otc_tag *tags, int num_tags, char **err);
+int                      ot_span_tag(struct otc_span *span, const struct otc_tag *tags, int num_tags);
+int                      ot_span_log(struct otc_span *span, const struct otc_log_field *log_fields, int num_fields);
+int                      ot_span_set_baggage(struct otc_span *span, const struct otc_text_map *baggage);
+struct otc_span_context *ot_inject_http_headers(struct otc_tracer *tracer, const struct otc_span *span, struct otc_http_headers_writer *carrier, char **err);
+struct otc_span_context *ot_extract_http_headers(struct otc_tracer *tracer, struct otc_http_headers_reader *carrier, const struct otc_text_map *text_map, char **err);
+void                     ot_span_finish(struct otc_span **span, const struct timespec *ts_finish, const struct timespec *log_ts, const char *log_key, const char *log_value, ...);
+void                     ot_close(struct otc_tracer **tracer);
+
+/* Unused code. */
+struct otc_span         *ot_span_init_va(struct otc_tracer *tracer, const char *operation_name, const struct timespec *ts_steady, const struct timespec *ts_system, int ref_type, int ref_ctx_idx, const struct otc_span *ref_span, char **err, const char *tag_key, const char *tag_value, ...);
+int                      ot_span_tag_va(struct otc_span *span, const char *key, int type, ...);
+int                      ot_span_log_va(struct otc_span *span, const char *key, const char *value, ...);
+int                      ot_span_log_fmt(struct otc_span *span, const char *key, const char *format, ...) __attribute__ ((format(printf, 3, 4)));
+int                      ot_span_set_baggage_va(struct otc_span *span, const char *key, const char *value, ...);
+struct otc_text_map     *ot_span_baggage_va(const struct otc_span *span, const char *key, ...);
+struct otc_span_context *ot_inject_text_map(struct otc_tracer *tracer, const struct otc_span *span, struct otc_text_map_writer *carrier);
+struct otc_span_context *ot_inject_binary(struct otc_tracer *tracer, const struct otc_span *span, struct otc_custom_carrier_writer *carrier);
+struct otc_span_context *ot_extract_text_map(struct otc_tracer *tracer, struct otc_text_map_reader *carrier, const struct otc_text_map *text_map);
+struct otc_span_context *ot_extract_binary(struct otc_tracer *tracer, struct otc_custom_carrier_reader *carrier, const struct otc_binary_data *binary_data);
+
+#endif /* _OPENTRACING_OT_H_ */
+
+/*
+ * Local variables:
+ *  c-indent-level: 8
+ *  c-basic-offset: 8
+ * End:
+ *
+ * vi: noexpandtab shiftwidth=8 tabstop=8
+ */
diff --git a/addons/ot/include/parser.h b/addons/ot/include/parser.h
new file mode 100644
index 0000000..53e414b
--- /dev/null
+++ b/addons/ot/include/parser.h
@@ -0,0 +1,172 @@
+/***
+ * Copyright 2020 HAProxy Technologies
+ *
+ * This file is part of the HAProxy OpenTracing filter.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
+ */
+#ifndef _OPENTRACING_PARSER_H_
+#define _OPENTRACING_PARSER_H_
+
+#define FLT_OT_SCOPE                        "OT"
+
+/*
+ * filter FLT_OT_OPT_NAME FLT_OT_OPT_FILTER_ID <FLT_OT_OPT_FILTER_ID_DEFAULT> FLT_OT_OPT_CONFIG <file>
+ */
+#define FLT_OT_OPT_NAME                     "opentracing"
+#define FLT_OT_OPT_FILTER_ID                "id"
+#define FLT_OT_OPT_FILTER_ID_DEFAULT        "ot-filter"
+#define FLT_OT_OPT_CONFIG                   "config"
+
+#define FLT_OT_PARSE_SECTION_TRACER_ID      "ot-tracer"
+#define FLT_OT_PARSE_SECTION_GROUP_ID       "ot-group"
+#define FLT_OT_PARSE_SECTION_SCOPE_ID       "ot-scope"
+
+#define FLT_OT_PARSE_SPAN_ROOT              "root"
+#define FLT_OT_PARSE_SPAN_REF_CHILD         "child-of"
+#define FLT_OT_PARSE_SPAN_REF_FOLLOWS       "follows-from"
+#define FLT_OT_PARSE_CTX_AUTONAME           "-"
+#define FLT_OT_PARSE_CTX_IGNORE_NAME        '-'
+#define FLT_OT_PARSE_CTX_USE_HEADERS        "use-headers"
+#define FLT_OT_PARSE_CTX_USE_VARS           "use-vars"
+#define FLT_OT_PARSE_OPTION_HARDERR         "hard-errors"
+#define FLT_OT_PARSE_OPTION_DISABLED        "disabled"
+#define FLT_OT_PARSE_OPTION_NOLOGNORM       "dontlog-normal"
+
+/*
+ * A description of the macro arguments can be found in the structure
+ * flt_ot_parse_data definition
+ */
+#define FLT_OT_PARSE_TRACER_DEFINES                                                                                                                          \
+	FLT_OT_PARSE_TRACER_DEF(         ID, 0, CHAR, 2, 2, "ot-tracer",   " <name>")                                                                           \
+	FLT_OT_PARSE_TRACER_DEF(        ACL, 0, CHAR, 3, 0, "acl",         " <name> <criterion> [flags] [operator] <value> ...")                                \
+	FLT_OT_PARSE_TRACER_DEF(        LOG, 0, CHAR, 2, 0, "log",         " { global | <addr> [len <len>] [format <fmt>] <facility> [<level> [<minlevel>]] }") \
+	FLT_OT_PARSE_TRACER_DEF(     CONFIG, 0, NONE, 2, 2, "config",      " <file>")                                                                           \
+	FLT_OT_PARSE_TRACER_DEF(     PLUGIN, 0, NONE, 2, 2, "plugin",      " <file>")                                                                           \
+	FLT_OT_PARSE_TRACER_DEF(     GROUPS, 0, NONE, 2, 0, "groups",      " <name> ...")                                                                       \
+	FLT_OT_PARSE_TRACER_DEF(     SCOPES, 0, NONE, 2, 0, "scopes",      " <name> ...")                                                                       \
+	FLT_OT_PARSE_TRACER_DEF( RATE_LIMIT, 0, NONE, 2, 2, "rate-limit",  " <value>")                                                                          \
+	FLT_OT_PARSE_TRACER_DEF(     OPTION, 0, NONE, 2, 2, "option",      " { disabled | dontlog-normal | hard-errors }")                                      \
+	FLT_OT_PARSE_TRACER_DEF(DEBUG_LEVEL, 0, NONE, 2, 2, "debug-level", " <value>")
+
+#define FLT_OT_PARSE_GROUP_DEFINES                                        \
+	FLT_OT_PARSE_GROUP_DEF(    ID, 0, CHAR, 2, 2, "ot-group", " <name>") \
+	FLT_OT_PARSE_GROUP_DEF(SCOPES, 0, NONE, 2, 0, "scopes",   " <name> ...")
+
+#ifdef USE_OT_VARS
+#  define FLT_OT_PARSE_SCOPE_INJECT_HELP    " <name-prefix> [use-vars] [use-headers]"
+#  define FLT_OT_PARSE_SCOPE_EXTRACT_HELP   " <name-prefix> [use-vars | use-headers]"
+#else
+#  define FLT_OT_PARSE_SCOPE_INJECT_HELP    " <name-prefix> [use-headers]"
+#  define FLT_OT_PARSE_SCOPE_EXTRACT_HELP   " <name-prefix> [use-headers]"
+#endif
+
+/*
+ * In case the possibility of working with OpenTracing context via HAProxyu
+ * variables is not used, args_max member of the structure flt_ot_parse_data
+ * should be reduced for 'inject' keyword.  However, this is not critical
+ * because in this case the 'use-vars' argument cannot be entered anyway,
+ * so I will not complicate it here with additional definitions.
+ */
+#define FLT_OT_PARSE_SCOPE_DEFINES                                                                                    \
+	FLT_OT_PARSE_SCOPE_DEF(     ID, 0, CHAR, 2, 2, "ot-scope", " <name>")                                            \
+	FLT_OT_PARSE_SCOPE_DEF(   SPAN, 0, NONE, 2, 5, "span",     " <name> [<reference>] [root]")                       \
+	FLT_OT_PARSE_SCOPE_DEF(    TAG, 1, NONE, 3, 0, "tag",      " <name> <sample> ...")                               \
+	FLT_OT_PARSE_SCOPE_DEF(    LOG, 1, NONE, 3, 0, "log",      " <name> <sample> ...")                               \
+	FLT_OT_PARSE_SCOPE_DEF(BAGGAGE, 1,  VAR, 3, 0, "baggage",  " <name> <sample> ...")                               \
+	FLT_OT_PARSE_SCOPE_DEF( INJECT, 1,  CTX, 2, 4, "inject",   FLT_OT_PARSE_SCOPE_INJECT_HELP)                       \
+	FLT_OT_PARSE_SCOPE_DEF(EXTRACT, 0,  CTX, 2, 3, "extract",  FLT_OT_PARSE_SCOPE_EXTRACT_HELP)                      \
+	FLT_OT_PARSE_SCOPE_DEF( FINISH, 0, NONE, 2, 0, "finish",   " <name> ...")                                        \
+	FLT_OT_PARSE_SCOPE_DEF(    ACL, 0, CHAR, 3, 0, "acl",      " <name> <criterion> [flags] [operator] <value> ...") \
+	FLT_OT_PARSE_SCOPE_DEF(  EVENT, 0, NONE, 2, 0, "event",    " <name> [{ if | unless } <condition>]")
+
+enum FLT_OT_PARSE_INVCHAR_enum {
+	FLT_OT_PARSE_INVALID_NONE,
+	FLT_OT_PARSE_INVALID_CHAR,
+	FLT_OT_PARSE_INVALID_DOM,
+	FLT_OT_PARSE_INVALID_CTX,
+	FLT_OT_PARSE_INVALID_VAR,
+};
+
+enum FLT_OT_PARSE_TRACER_enum {
+#define FLT_OT_PARSE_TRACER_DEF(a,b,c,d,e,f,g)   FLT_OT_PARSE_TRACER_##a,
+	FLT_OT_PARSE_TRACER_DEFINES
+#undef FLT_OT_PARSE_TRACER_DEF
+};
+
+enum FLT_OT_PARSE_GROUP_enum {
+#define FLT_OT_PARSE_GROUP_DEF(a,b,c,d,e,f,g)   FLT_OT_PARSE_GROUP_##a,
+	FLT_OT_PARSE_GROUP_DEFINES
+#undef FLT_OT_PARSE_GROUP_DEF
+};
+
+enum FLT_OT_PARSE_SCOPE_enum {
+#define FLT_OT_PARSE_SCOPE_DEF(a,b,c,d,e,f,g)   FLT_OT_PARSE_SCOPE_##a,
+	FLT_OT_PARSE_SCOPE_DEFINES
+#undef FLT_OT_PARSE_SCOPE_DEF
+};
+
+enum FLT_OT_CTX_USE_enum {
+	FLT_OT_CTX_USE_VARS    = 1 << 0,
+	FLT_OT_CTX_USE_HEADERS = 1 << 1,
+};
+
+struct flt_ot_parse_data {
+	int         keyword;       /* Keyword index. */
+	bool        flag_check_id; /* Whether the group ID must be defined for the keyword. */
+	int         check_name;    /* Checking allowed characters in the name. */
+	int         args_min;      /* The minimum number of arguments required. */
+	int         args_max;      /* The maximum number of arguments allowed. */
+	const char *name;          /* Keyword name. */
+	const char *usage;         /* Usage text to be printed in case of an error. */
+};
+
+#define FLT_OT_PARSE_WARNING(f, ...) \
+	ha_warning("parsing [%s:%d] : " FLT_OT_FMT_TYPE FLT_OT_FMT_NAME "'" f "'\n", ##__VA_ARGS__);
+#define FLT_OT_PARSE_ALERT(f, ...)                                                                         \
+	do {                                                                                               \
+		ha_alert("parsing [%s:%d] : " FLT_OT_FMT_TYPE FLT_OT_FMT_NAME "'" f "'\n", ##__VA_ARGS__); \
+                                                                                                           \
+		retval |= ERR_ABORT | ERR_ALERT;                                                           \
+	} while (0)
+#define FLT_OT_POST_PARSE_ALERT(f, ...) \
+	FLT_OT_PARSE_ALERT(f, flt_ot_current_config->cfg_file, ##__VA_ARGS__)
+
+#define FLT_OT_PARSE_ERR(e,f, ...)                              \
+	do {                                                    \
+		if (*(e) == NULL)                               \
+			(void)memprintf((e), f, ##__VA_ARGS__); \
+                                                                \
+		retval |= ERR_ABORT | ERR_ALERT;                \
+	} while (0)
+#define FLT_OT_PARSE_IFERR_ALERT()                            \
+	do {                                                  \
+		if (err == NULL)                              \
+			break;                                \
+                                                              \
+		FLT_OT_PARSE_ALERT("%s", file, linenum, err); \
+		FLT_OT_ERR_FREE(err);                         \
+	} while (0)
+
+#endif /* _OPENTRACING_PARSER_H_ */
+
+/*
+ * Local variables:
+ *  c-indent-level: 8
+ *  c-basic-offset: 8
+ * End:
+ *
+ * vi: noexpandtab shiftwidth=8 tabstop=8
+ */
diff --git a/addons/ot/include/pool.h b/addons/ot/include/pool.h
new file mode 100644
index 0000000..df72c84
--- /dev/null
+++ b/addons/ot/include/pool.h
@@ -0,0 +1,39 @@
+/***
+ * Copyright 2020 HAProxy Technologies
+ *
+ * This file is part of the HAProxy OpenTracing filter.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
+ */
+#ifndef _OPENTRACING_POOL_H_
+#define _OPENTRACING_POOL_H_
+
+void          *flt_ot_pool_alloc(struct pool_head *pool, size_t size, bool flag_clear, char **err);
+void          *flt_ot_pool_strndup(struct pool_head *pool, const char *s, size_t size, char **err);
+void           flt_ot_pool_free(struct pool_head *pool, void **ptr);
+
+struct buffer *flt_ot_trash_alloc(bool flag_clear, char **err);
+void           flt_ot_trash_free(struct buffer **ptr);
+
+#endif /* _OPENTRACING_POOL_H_ */
+
+/*
+ * Local variables:
+ *  c-indent-level: 8
+ *  c-basic-offset: 8
+ * End:
+ *
+ * vi: noexpandtab shiftwidth=8 tabstop=8
+ */
diff --git a/addons/ot/include/scope.h b/addons/ot/include/scope.h
new file mode 100644
index 0000000..7a3a776
--- /dev/null
+++ b/addons/ot/include/scope.h
@@ -0,0 +1,126 @@
+/***
+ * Copyright 2020 HAProxy Technologies
+ *
+ * This file is part of the HAProxy OpenTracing filter.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
+ */
+#ifndef _OPENTRACING_SCOPE_H_
+#define _OPENTRACING_SCOPE_H_
+
+#define FLT_OT_SCOPE_SPAN_FINISH_REQ   "*req*"
+#define FLT_OT_SCOPE_SPAN_FINISH_RES   "*res*"
+#define FLT_OT_SCOPE_SPAN_FINISH_ALL   "*"
+
+#define FLT_OT_RT_CTX(a)               ((struct flt_ot_runtime_context *)(a))
+
+#define FLT_OT_DBG_SCOPE_SPAN(f,a)                                         \
+	FLT_OT_DBG(3, "%s%p:{ '%s' %zu %u %hhu %p %d %p %p }",             \
+	           (f), (a), FLT_OT_STR_HDR_ARGS(a, id), (a)->smp_opt_dir, \
+	           (a)->flag_finish, (a)->span, (a)->ref_type, (a)->ref_span, (a)->ref_ctx)
+
+#define FLT_OT_DBG_SCOPE_CONTEXT(f,a)                                      \
+	FLT_OT_DBG(3, "%s%p:{ '%s' %zu %u %hhu %p }",                      \
+	           (f), (a), FLT_OT_STR_HDR_ARGS(a, id), (a)->smp_opt_dir, \
+	           (a)->flag_finish, (a)->context)
+
+#define FLT_OT_DBG_SCOPE_DATA(f,a)               \
+	FLT_OT_DBG(3, "%s%p:{ %p %d %p %p %d }", \
+	           (f), (a), (a)->tags, (a)->num_tags, (a)->baggage, (a)->log_fields, (a)->num_log_fields)
+
+#define FLT_OT_DBG_RUNTIME_CONTEXT(f,a)                                                                \
+	FLT_OT_DBG(3, "%s%p:{ %p %p '%s' %hhu %hhu 0x%02hhx 0x%08x %s %s }",                           \
+	           (f), (a), (a)->stream, (a)->filter, (a)->uuid, (a)->flag_harderr,                   \
+	           (a)->flag_disabled, (a)->logging, (a)->analyzers, flt_ot_list_debug(&((a)->spans)), \
+	           flt_ot_list_debug(&((a)->contexts)))
+
+#define FLT_OT_CONST_STR_HDR(a)      \
+	struct {                     \
+		const char *a;       \
+		size_t      a##_len; \
+	}
+
+
+struct flt_ot_scope_data {
+	struct otc_tag        tags[FLT_OT_MAXTAGS];         /* Defined tags. */
+	int                   num_tags;                     /* The number of tags used. */
+	struct otc_text_map  *baggage;                      /* Defined baggage. */
+	struct otc_log_field  log_fields[OTC_MAXLOGFIELDS]; /* Defined logs. */
+	int                   num_log_fields;               /* The number of log fields used. */
+};
+
+/* flt_ot_runtime_context->spans */
+struct flt_ot_scope_span {
+	FLT_OT_CONST_STR_HDR(id);               /* The span operation name/len. */
+	uint                       smp_opt_dir; /* SMP_OPT_DIR_RE(Q|S) */
+	bool                       flag_finish; /* Whether the span is marked for completion. */
+	struct otc_span           *span;        /* The current span. */
+	otc_span_reference_type_t  ref_type;    /* Span reference type. */
+	struct otc_span           *ref_span;    /* Span to which the current span refers. */
+	struct otc_span_context   *ref_ctx;     /* Span context to which the current span refers. */
+	struct list                list;        /* Used to chain this structure. */
+};
+
+/* flt_ot_runtime_context->contexts */
+struct flt_ot_scope_context {
+	FLT_OT_CONST_STR_HDR(id);             /* The span context name/len. */
+	uint                     smp_opt_dir; /* SMP_OPT_DIR_RE(Q|S) */
+	bool                     flag_finish; /* Whether the span context is marked for completion. */
+	struct otc_span_context *context;     /* The current span context. */
+	struct list              list;        /* Used to chain this structure. */
+};
+
+/* The runtime filter context attached to a stream. */
+struct flt_ot_runtime_context {
+	struct stream      *stream;        /* The stream to which the filter is attached. */
+	struct filter      *filter;        /* The OpenTracing filter. */
+	char                uuid[40];      /* Randomly generated UUID. */
+	bool                flag_harderr;  /* [0 1] */
+	bool                flag_disabled; /* [0 1] */
+	uint8_t             logging;       /* [0 1 3] */
+	uint                analyzers;     /* Executed channel analyzers. */
+	struct list         spans;         /* The scope spans. */
+	struct list         contexts;      /* The scope contexts. */
+};
+
+
+#ifndef DEBUG_OT
+#  define flt_ot_pools_info()   while (0)
+#else
+void                           flt_ot_pools_info(void);
+#endif
+struct flt_ot_runtime_context *flt_ot_runtime_context_init(struct stream *s, struct filter *f, char **err);
+void                           flt_ot_runtime_context_free(struct filter *f);
+
+struct flt_ot_scope_span      *flt_ot_scope_span_init(struct flt_ot_runtime_context *rt_ctx, const char *id, size_t id_len, otc_span_reference_type_t ref_type, const char *ref_id, size_t ref_id_len, uint dir, char **err);
+void                           flt_ot_scope_span_free(struct flt_ot_scope_span **ptr);
+struct flt_ot_scope_context   *flt_ot_scope_context_init(struct flt_ot_runtime_context *rt_ctx, struct otc_tracer *tracer, const char *id, size_t id_len, const struct otc_text_map *text_map, uint dir, char **err);
+void                           flt_ot_scope_context_free(struct flt_ot_scope_context **ptr);
+void                           flt_ot_scope_data_free(struct flt_ot_scope_data *ptr);
+
+int                            flt_ot_scope_finish_mark(const struct flt_ot_runtime_context *rt_ctx, const char *id, size_t id_len);
+void                           flt_ot_scope_finish_marked(const struct flt_ot_runtime_context *rt_ctx, const struct timespec *ts_finish);
+void                           flt_ot_scope_free_unused(struct flt_ot_runtime_context *rt_ctx, struct channel *chn);
+
+#endif /* _OPENTRACING_SCOPE_H_ */
+
+/*
+ * Local variables:
+ *  c-indent-level: 8
+ *  c-basic-offset: 8
+ * End:
+ *
+ * vi: noexpandtab shiftwidth=8 tabstop=8
+ */
diff --git a/addons/ot/include/util.h b/addons/ot/include/util.h
new file mode 100644
index 0000000..776ddd2
--- /dev/null
+++ b/addons/ot/include/util.h
@@ -0,0 +1,109 @@
+/***
+ * Copyright 2020 HAProxy Technologies
+ *
+ * This file is part of the HAProxy OpenTracing filter.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
+ */
+#ifndef _OPENTRACING_UTIL_H_
+#define _OPENTRACING_UTIL_H_
+
+#define HTTP_METH_STR_OPTIONS   "OPTIONS"
+#define HTTP_METH_STR_GET       "GET"
+#define HTTP_METH_STR_HEAD      "HEAD"
+#define HTTP_METH_STR_POST      "POST"
+#define HTTP_METH_STR_PUT       "PUT"
+#define HTTP_METH_STR_DELETE    "DELETE"
+#define HTTP_METH_STR_TRACE     "TRACE"
+#define HTTP_METH_STR_CONNECT   "CONNECT"
+
+/* Defined in include/haproxy/channel-t.h. */
+#define FLT_OT_AN_DEFINES                     \
+	FLT_OT_AN_DEF(AN_REQ_INSPECT_FE)      \
+	FLT_OT_AN_DEF(AN_REQ_WAIT_HTTP)       \
+	FLT_OT_AN_DEF(AN_REQ_HTTP_BODY)       \
+	FLT_OT_AN_DEF(AN_REQ_HTTP_PROCESS_FE) \
+	FLT_OT_AN_DEF(AN_REQ_SWITCHING_RULES) \
+	FLT_OT_AN_DEF(AN_REQ_INSPECT_BE)      \
+	FLT_OT_AN_DEF(AN_REQ_HTTP_PROCESS_BE) \
+	FLT_OT_AN_DEF(AN_REQ_HTTP_TARPIT)     \
+	FLT_OT_AN_DEF(AN_REQ_SRV_RULES)       \
+	FLT_OT_AN_DEF(AN_REQ_HTTP_INNER)      \
+	FLT_OT_AN_DEF(AN_REQ_PRST_RDP_COOKIE) \
+	FLT_OT_AN_DEF(AN_REQ_STICKING_RULES)  \
+	FLT_OT_AN_DEF(AN_REQ_HTTP_XFER_BODY)  \
+	FLT_OT_AN_DEF(AN_REQ_WAIT_CLI)        \
+	FLT_OT_AN_DEF(AN_RES_INSPECT)         \
+	FLT_OT_AN_DEF(AN_RES_WAIT_HTTP)       \
+	FLT_OT_AN_DEF(AN_RES_STORE_RULES)     \
+	FLT_OT_AN_DEF(AN_RES_HTTP_PROCESS_BE) \
+	FLT_OT_AN_DEF(AN_RES_HTTP_PROCESS_FE) \
+	FLT_OT_AN_DEF(AN_RES_HTTP_XFER_BODY)  \
+	FLT_OT_AN_DEF(AN_RES_WAIT_CLI)
+
+#define FLT_OT_PROXIES_LIST_START()                                             \
+	do {                                                                    \
+		struct flt_conf *fconf;                                         \
+		struct proxy    *px;                                            \
+                                                                                \
+		for (px = proxies_list; px != NULL; px = px->next)              \
+			list_for_each_entry(fconf, &(px->filter_configs), list) \
+				if (fconf->id == ot_flt_id) {                   \
+					struct flt_ot_conf *conf = fconf->conf;
+#define FLT_OT_PROXIES_LIST_END() \
+				} \
+	} while (0)
+
+#ifdef DEBUG_OT
+#  define FLT_OT_ARGS_DUMP()   do { if (flt_ot_debug.level & (1 << 2)) flt_ot_args_dump(args); } while (0)
+#else
+#  define FLT_OT_ARGS_DUMP()   while (0)
+#endif
+
+
+#ifndef DEBUG_OT
+#  define flt_ot_filters_dump()   while (0)
+#else
+void        flt_ot_args_dump(char **args);
+void        flt_ot_filters_dump(void);
+const char *flt_ot_chn_label(const struct channel *chn);
+const char *flt_ot_pr_mode(const struct stream *s);
+const char *flt_ot_stream_pos(const struct stream *s);
+const char *flt_ot_type(const struct filter *f);
+const char *flt_ot_analyzer(uint an_bit);
+const char *flt_ot_str_hex(const void *data, size_t size);
+const char *flt_ot_str_ctrl(const void *data, size_t size);
+const char *flt_ot_list_debug(const struct list *head);
+#endif
+
+ssize_t     flt_ot_chunk_add(struct buffer *chk, const void *src, size_t n, char **err);
+int         flt_ot_args_count(char **args);
+void        flt_ot_args_to_str(char **args, int idx, char **str);
+double      flt_ot_strtod(const char *nptr, double limit_min, double limit_max, char **err);
+int64_t     flt_ot_strtoll(const char *nptr, int64_t limit_min, int64_t limit_max, char **err);
+int         flt_ot_sample_to_str(const struct sample_data *data, char *value, size_t size, char **err);
+int         flt_ot_sample_to_value(const char *key, const struct sample_data *data, struct otc_value *value, char **err);
+int         flt_ot_sample_add(struct stream *s, uint dir, struct flt_ot_conf_sample *sample, struct flt_ot_scope_data *data, int type, char **err);
+
+#endif /* _OPENTRACING_UTIL_H_ */
+
+/*
+ * Local variables:
+ *  c-indent-level: 8
+ *  c-basic-offset: 8
+ * End:
+ *
+ * vi: noexpandtab shiftwidth=8 tabstop=8
+ */
diff --git a/addons/ot/include/vars.h b/addons/ot/include/vars.h
new file mode 100644
index 0000000..550cc89
--- /dev/null
+++ b/addons/ot/include/vars.h
@@ -0,0 +1,55 @@
+/***
+ * Copyright 2020 HAProxy Technologies
+ *
+ * This file is part of the HAProxy OpenTracing filter.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
+ */
+#ifndef _OPENTRACING_VARS_H_
+#define _OPENTRACING_VARS_H_
+
+#define FLT_OT_VARS_SCOPE       "txn"
+#define FLT_OT_VAR_CTX_SIZE     int8_t
+#define FLT_OT_VAR_CHAR_DASH    'D'
+#define FLT_OT_VAR_CHAR_SPACE   'S'
+
+struct flt_ot_ctx {
+	char value[BUFSIZ];
+	int  value_len;
+};
+
+typedef int (*flt_ot_ctx_loop_cb)(struct sample *, size_t, const char *, const char *, const char *, FLT_OT_VAR_CTX_SIZE, char **, void *);
+
+
+#ifndef DEBUG_OT
+#  define flt_ot_vars_dump(...)   while (0)
+#else
+void                 flt_ot_vars_dump(struct stream *s);
+#endif
+int                  flt_ot_var_register(const char *scope, const char *prefix, const char *name, char **err);
+int                  flt_ot_var_set(struct stream *s, const char *scope, const char *prefix, const char *name, const char *value, uint opt, char **err);
+int                  flt_ot_vars_unset(struct stream *s, const char *scope, const char *prefix, uint opt, char **err);
+struct otc_text_map *flt_ot_vars_get(struct stream *s, const char *scope, const char *prefix, uint opt, char **err);
+
+#endif /* _OPENTRACING_VARS_H_ */
+
+/*
+ * Local variables:
+ *  c-indent-level: 8
+ *  c-basic-offset: 8
+ * End:
+ *
+ * vi: noexpandtab shiftwidth=8 tabstop=8
+ */