BUG/MINOR: http-act: Properly generate 103 responses when several rules are used

When several "early-hint" rules are used, we try, as far as possible, to
merge links into the same 103-early-hints response. However, it only works
if there is no ACLs. If a "early-hint" rule is not executed an invalid
response is generated. the EOH block or the start-line may be missing,
depending on the rule order.

To fix the bug, we use the transaction status code. It is unused at this
stage. Thus, it is set to 103 when a 103-early-hints response is in
progress. And it is reset when the response is forwarded. In addition, the
response is forwarded if the next rule is an "early-hint" rule with an
ACL. This way, the response is always valid.

This patch must be backported as far as 2.2.

diff --git a/src/http_act.c b/src/http_act.c
index de462d298fa5cb0ba782a374d68c20d7e5089513..36c042a9173b100cfcf5da8b43dad0c7416c97a2 100644 (file)
--- a/src/http_act.c
+++ b/src/http_act.c
@@ -1348,7 +1348,7 @@ static enum act_parse_ret parse_http_auth(const char **args, int *orig_arg, stru
 static enum act_return http_action_early_hint(struct act_rule *rule, struct proxy *px,
                                              struct session *sess, struct stream *s, int flags)
 {
-       struct act_rule *prev_rule, *next_rule;
+       struct act_rule *next_rule;
        struct channel *res = &s->res;
        struct htx *htx = htx_from_buf(&res->buf);
        struct buffer *value = alloc_trash_chunk();
@@ -1363,13 +1363,10 @@ static enum act_return http_action_early_hint(struct act_rule *rule, struct prox
                goto error;
        }
 
-       /* get previous and next rules */
-       prev_rule = LIST_PREV(&rule->list, typeof(rule), list);
-       next_rule = LIST_NEXT(&rule->list, typeof(rule), list);
-
-       /* if no previous rule or previous rule is not early-hint, start a new response. Otherwise,
-        * continue to add link to a previously started response */
-       if (&prev_rule->list == s->current_rule_list || prev_rule->action_ptr != http_action_early_hint) {
+       /* if there is no pending 103 response, start a new response. Otherwise,
+        * continue to add link to a previously started response
+         */
+       if (s->txn->status != 103) {
                struct htx_sl *sl;
                unsigned int flags = (HTX_SL_F_IS_RESP|HTX_SL_F_VER_11|
                                      HTX_SL_F_XFER_LEN|HTX_SL_F_BODYLESS);
@@ -1379,6 +1376,7 @@ static enum act_return http_action_early_hint(struct act_rule *rule, struct prox
                if (!sl)
                        goto error;
                sl->info.res.status = 103;
+               s->txn->status = 103;
        }
 
        /* Add the HTTP Early Hint HTTP 103 response heade */
@@ -1386,18 +1384,16 @@ static enum act_return http_action_early_hint(struct act_rule *rule, struct prox
        if (!htx_add_header(htx, rule->arg.http.str, ist2(b_head(value), b_data(value))))
                goto error;
 
-       /* if it is the last rule or the next one is not an early-hint, terminate the current
-        * response. */
-       if (&next_rule->list == s->current_rule_list || next_rule->action_ptr != http_action_early_hint) {
-               if (!htx_add_endof(htx, HTX_BLK_EOH)) {
-                       /* If an error occurred during an Early-hint rule,
-                        * remove the incomplete HTTP 103 response from the
-                        * buffer */
+       /* if it is the last rule or the next one is not an early-hint or an
+        * conditional early-hint, terminate the current response.
+        */
+       next_rule = LIST_NEXT(&rule->list, typeof(rule), list);
+       if (&next_rule->list == s->current_rule_list || next_rule->action_ptr != http_action_early_hint || next_rule->cond) {
+               if (!htx_add_endof(htx, HTX_BLK_EOH))
                        goto error;
-               }
-
                if (!http_forward_proxy_resp(s, 0))
                        goto error;
+               s->txn->status = 0;
        }
 
   leave:
@@ -1409,6 +1405,7 @@ static enum act_return http_action_early_hint(struct act_rule *rule, struct prox
         * HTTP 103 response from the buffer */
        channel_htx_truncate(res, htx);
        ret = ACT_RET_ERR;
+       s->txn->status = 0;
        goto leave;
 }