From 09710e07305369be6638f4ada597a4b186b3fe97 Mon Sep 17 00:00:00 2001
From: Karel Slany <karel.slany@nic.cz>
Date: Tue, 24 May 2016 12:06:13 +0200
Subject: [PATCH] Force fall-back to TCP when bad cookie received.
---
modules/cookies/cookies.c | 22 ++++++++++++----------
1 file changed, 12 insertions(+), 10 deletions(-)
diff --git a/modules/cookies/cookies.c b/modules/cookies/cookies.c
index 28632cfe3..84498b056 100644
--- a/modules/cookies/cookies.c
+++ b/modules/cookies/cookies.c
@@ -149,8 +149,13 @@ static int check_response(knot_layer_t *ctx, knot_pkt_t *pkt)
return ctx->state;
}
+ struct kr_request *req = ctx->data;
+ struct kr_query *qry = req->current_query;
+ struct kr_nsrep *ns = &qry->ns;
+
uint8_t *cookie_opt = knot_edns_get_option(pkt->opt_rr, KNOT_EDNS_OPTION_COOKIE);
if (!cookie_opt) {
+ /* Don't do anything if no cookies received. */
return ctx->state;
}
@@ -165,8 +170,9 @@ static int check_response(knot_layer_t *ctx, knot_pkt_t *pkt)
&cc, &cc_len, &sc, &sc_len);
if (ret != KNOT_EOK) {
DEBUG_MSG(NULL, "%s\n", "received malformed DNS cookie");
- /* TODO -- Generate error. */
- return ctx->state;
+ DEBUG_MSG(NULL, "%s'n", "falling back to TCP");
+ qry->flags |= QUERY_TCP;
+ return KNOT_STATE_PRODUCE;
}
assert(cc_len == KNOT_OPT_COOKIE_CLNT);
@@ -175,17 +181,13 @@ static int check_response(knot_layer_t *ctx, knot_pkt_t *pkt)
const struct sockaddr *srvr_sockaddr = NULL;
- struct kr_request *req = ctx->data;
- struct kr_query *qry = req->current_query;
- struct kr_nsrep *ns = &qry->ns;
-
/* Abusing name server reputation mechanism to obtain IP addresses. */
srvr_sockaddr = guess_server_addr(cc, ns, kr_cookies_control.secret);
if (!srvr_sockaddr) {
- DEBUG_MSG(NULL, "%s\n",
- "could not ensure any server for received cookie");
- /* TODO -- Generate error. */
- return ctx->state;
+ DEBUG_MSG(NULL, "%s\n", "could not match received cookie");
+ DEBUG_MSG(NULL, "%s\n", "falling back to TCP");
+ qry->flags |= QUERY_TCP;
+ return KNOT_STATE_PRODUCE;
}
if (!is_cookie_cached(&kr_cookies_control.cache, srvr_sockaddr,
--
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