Like it has been done in commit 2ecba2d1e45b ("net: sched: act_csum: Fix
csum calc for tagged packets"), also 'pedit' needs to adjust the network
offset when multiple tags are present in the packets: otherwise wrong IP
headers (but good checksums) can be observed with the following command:
# tc filter add dev test0 parent ffff: protocol 802.1Q flower \
vlan_ethtype ipv4 action \
pedit ex munge ip ttl set 10 pipe \
csum ip and icmp pipe \
mirred egress redirect dev test1
Reported-by: Li Shuang <shu...@redhat.com>
Fixes: d8b9605d2697 ("net: sched: fix skb->protocol use in case of accelerated
vlan path")
Signed-off-by: Davide Caratti <dcara...@redhat.com>
---
net/sched/act_pedit.c | 38 ++++++++++++++++++++++++++++++++++----
1 file changed, 34 insertions(+), 4 deletions(-)
diff --git a/net/sched/act_pedit.c b/net/sched/act_pedit.c
index d790c02b9c6c..25dcf9ee092e 100644
--- a/net/sched/act_pedit.c
+++ b/net/sched/act_pedit.c
@@ -277,9 +277,12 @@ static bool offset_valid(struct sk_buff *skb, int offset)
}
static int pedit_skb_hdr_offset(struct sk_buff *skb,
- enum pedit_header_type htype, int *hoffset)
+ enum pedit_header_type htype, int *hoffset,
+ unsigned int *vlan_hdr_count)
{
+ bool orig_vlan_tag_present = false;
int ret = -EINVAL;
+ __be16 protocol;
switch (htype) {
case TCA_PEDIT_KEY_EX_HDR_TYPE_ETH:
@@ -291,8 +294,29 @@ static int pedit_skb_hdr_offset(struct sk_buff *skb,
case TCA_PEDIT_KEY_EX_HDR_TYPE_NETWORK:
case TCA_PEDIT_KEY_EX_HDR_TYPE_IP4:
case TCA_PEDIT_KEY_EX_HDR_TYPE_IP6:
- *hoffset = skb_network_offset(skb);
- ret = 0;
+ protocol = tc_skb_protocol(skb);
+again:
+ switch (protocol) {
+ case cpu_to_be16(ETH_P_8021AD): /* fall through */
+ case cpu_to_be16(ETH_P_8021Q):
+ if (skb_vlan_tag_present(skb) &&
+ !orig_vlan_tag_present) {
+ protocol = skb->protocol;
+ orig_vlan_tag_present = true;
+ } else {
+ struct vlan_hdr *vlan;
+
+ vlan = (struct vlan_hdr *)skb->data;
+ protocol = vlan->h_vlan_encapsulated_proto;
+ skb_pull(skb, VLAN_HLEN);
+ skb_reset_network_header(skb);
+ (*vlan_hdr_count)++;
+ }
+ goto again;
+ default:
+ *hoffset = skb_network_offset(skb);
+ ret = 0;
+ }
break;
case TCA_PEDIT_KEY_EX_HDR_TYPE_TCP:
case TCA_PEDIT_KEY_EX_HDR_TYPE_UDP:
@@ -313,6 +337,7 @@ static int tcf_pedit_act(struct sk_buff *skb, const struct
tc_action *a,
struct tcf_result *res)
{
struct tcf_pedit *p = to_pedit(a);
+ unsigned int vlan_hdr_count = 0;
int i;
if (skb_unclone(skb, GFP_ATOMIC))
@@ -343,7 +368,8 @@ static int tcf_pedit_act(struct sk_buff *skb, const struct
tc_action *a,
tkey_ex++;
}
- rc = pedit_skb_hdr_offset(skb, htype, &hoffset);
+ rc = pedit_skb_hdr_offset(skb, htype, &hoffset,
+ &vlan_hdr_count);
if (rc) {
pr_info("tc action pedit bad header type
specified (0x%x)\n",
htype);
@@ -407,6 +433,10 @@ static int tcf_pedit_act(struct sk_buff *skb, const struct
tc_action *a,
bad:
p->tcf_qstats.overlimits++;
done:
+ while (vlan_hdr_count--) {
+ skb_push(skb, VLAN_HLEN);
+ skb_reset_network_header(skb);
+ }
bstats_update(&p->tcf_bstats, skb);
spin_unlock(&p->tcf_lock);
return p->tcf_action;
--
2.20.1
