There is a bug here in that the control connection should still be created even
though it is likely an unused control connection.
The following incremental fixes it.
diff --git a/lib/conntrack.c b/lib/conntrack.c
index fed9f61..18016c1 100644
--- a/lib/conntrack.c
+++ b/lib/conntrack.c
@@ -505,7 +505,7 @@ handle_alg_ctl(struct conntrack *ct, const struct
conn_lookup_ctx *ctx,
const struct conn *conn_for_expectation)
{
/* ALG control packet handling with expectation creation. */
- if (OVS_UNLIKELY(alg_helpers[ct_alg_ctl] && conn)) {
+ if (OVS_UNLIKELY(alg_helpers[ct_alg_ctl] && conn && conn->alg)) {
alg_helpers[ct_alg_ctl](ct, ctx, pkt, conn_for_expectation, now,
CT_FTP_CTL_INTEREST, nat);
}
@@ -871,15 +871,14 @@ conn_not_found(struct conntrack *ct, struct dp_packet
*pkt,
return nc;
}
- if (!ct_verify_helper(helper, ct_alg_ctl)) {
- return nc;
- }
-
nc = new_conn(&ct->buckets[bucket], pkt, &ctx->key, now);
ctx->conn = nc;
nc->rev_key = nc->key;
conn_key_reverse(&nc->rev_key);
- nc->alg = nullable_xstrdup(helper);
+
+ if (ct_verify_helper(helper, ct_alg_ctl)) {
+ nc->alg = nullable_xstrdup(helper);
+ }
if (alg_exp) {
nc->alg_related = true;
This deserves a test case and I created one, which I will submit with this patch
Darrell
On 11/22/17, 12:56 AM, "[email protected] on behalf of Darrell
Ball" <[email protected] on behalf of [email protected]> wrote:
Presently, alg processing is enabled by default to better exercise code.
This is similar to kernels before 4.7 as well. The recommended default
behavior in the newer kernels is to only process algs if a helper is
supplied in a conntrack rule. The behavior is changed to match the
later kernels.
Signed-off-by: Darrell Ball <[email protected]>
---
lib/conntrack.c | 35 +++++++++++++++++++++++++++++------
1 file changed, 29 insertions(+), 6 deletions(-)
diff --git a/lib/conntrack.c b/lib/conntrack.c
index 1364d05..fed9f61 100644
--- a/lib/conntrack.c
+++ b/lib/conntrack.c
@@ -819,6 +819,26 @@ conn_clean(struct conntrack *ct, struct conn *conn,
}
}
+static bool
+ct_verify_helper(const char *helper, enum ct_alg_ctl_type ct_alg_ctl)
+{
+ if (ct_alg_ctl == CT_ALG_CTL_NONE) {
+ return true;
+ } else if (helper) {
+ if ((ct_alg_ctl == CT_ALG_CTL_FTP) &&
+ !strncmp(helper, "ftp", strlen("ftp"))) {
+ return true;
+ } else if ((ct_alg_ctl == CT_ALG_CTL_TFTP) &&
+ !strncmp(helper, "tftp", strlen("tftp"))) {
+ return true;
+ } else {
+ return false;
+ }
+ } else {
+ return false;
+ }
+}
+
/* This function is called with the bucket lock held. */
static struct conn *
conn_not_found(struct conntrack *ct, struct dp_packet *pkt,
@@ -826,7 +846,8 @@ conn_not_found(struct conntrack *ct, struct dp_packet
*pkt,
const struct nat_action_info_t *nat_action_info,
struct conn *conn_for_un_nat_copy,
const char *helper,
- const struct alg_exp_node *alg_exp)
+ const struct alg_exp_node *alg_exp,
+ enum ct_alg_ctl_type ct_alg_ctl)
{
unsigned bucket = hash_to_bucket(ctx->hash);
struct conn *nc = NULL;
@@ -850,14 +871,15 @@ conn_not_found(struct conntrack *ct, struct dp_packet
*pkt,
return nc;
}
+ if (!ct_verify_helper(helper, ct_alg_ctl)) {
+ return nc;
+ }
+
nc = new_conn(&ct->buckets[bucket], pkt, &ctx->key, now);
ctx->conn = nc;
nc->rev_key = nc->key;
conn_key_reverse(&nc->rev_key);
-
- if (helper) {
- nc->alg = xstrdup(helper);
- }
+ nc->alg = nullable_xstrdup(helper);
if (alg_exp) {
nc->alg_related = true;
@@ -1222,7 +1244,8 @@ process_one(struct conntrack *ct, struct dp_packet
*pkt,
ct_rwlock_unlock(&ct->resources_lock);
conn = conn_not_found(ct, pkt, ctx, commit, now, nat_action_info,
- &conn_for_un_nat_copy, helper, alg_exp);
+ &conn_for_un_nat_copy, helper, alg_exp,
+ ct_alg_ctl);
}
write_ct_md(pkt, zone, conn, &ctx->key, alg_exp);
--
1.9.1
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