(2nd attempt to publish patch since update via “git send-mail” seems to be lost)
BPF filter arp_vlan_rpl_flt fails if in the ARP response the VLAN tag has,
in addition to VID, also PCP (priority code point).
This patch is masking the last 12 bits from SKF_AD_VLAN_TAG field
to extract VID only.
Signed-off-by: Robert Karbowski <robert_karbowski(a)hotmail.com>
---
teamd/teamd_lw_arp_ping.c | 7 ++++---
1 file changed, 4 insertions(+), 3 deletions(-)
diff --git a/teamd/teamd_lw_arp_ping.c b/teamd/teamd_lw_arp_ping.c
index c3d4710..5b5c044 100644
--- a/teamd/teamd_lw_arp_ping.c
+++ b/teamd/teamd_lw_arp_ping.c
@@ -90,10 +90,11 @@ static const struct sock_fprog arp_novlan_rpl_fprog = {
static struct sock_filter arp_vlan_rpl_flt[] = {
BPF_STMT(BPF_LD + BPF_B + BPF_ABS, SKF_AD_OFF + SKF_AD_PROTOCOL),
- BPF_JUMP(BPF_JMP + BPF_JEQ + BPF_K, ETH_P_ARP, 0, 8),
+ BPF_JUMP(BPF_JMP + BPF_JEQ + BPF_K, ETH_P_ARP, 0, 9),
BPF_STMT(BPF_LD + BPF_B + BPF_ABS, SKF_AD_OFF + SKF_AD_VLAN_TAG_PRESENT),
- BPF_JUMP(BPF_JMP + BPF_JEQ + BPF_K, 0, 6, 0),
+ BPF_JUMP(BPF_JMP + BPF_JEQ + BPF_K, 0, 7, 0),
BPF_STMT(BPF_LD + BPF_B + BPF_ABS, SKF_AD_OFF + SKF_AD_VLAN_TAG),
+ BPF_STMT(BPF_ALU + BPF_AND + BPF_K, 0xfff),
BPF_JUMP(BPF_JMP + BPF_JEQ + BPF_K, 0xffff, 0, 4), /* 0xffff will be replaced by vland id */
BPF_STMT(BPF_LD + BPF_H + BPF_ABS, OFFSET_ARP_OP_CODE),
BPF_JUMP(BPF_JMP + BPF_JEQ + BPF_K, ARPOP_REPLY, 1, 0),
@@ -103,7 +104,7 @@ static struct sock_filter arp_vlan_rpl_flt[] = {
};
/* this hack replaces vlanid value in filter code */
-#define SET_FILTER_VLANID(fprog, vlanid) (fprog)->filter[5].k = vlanid
+#define SET_FILTER_VLANID(fprog, vlanid) (fprog)->filter[6].k = vlanid
static const struct sock_fprog arp_vlan_rpl_fprog = {
.len = ARRAY_SIZE(arp_vlan_rpl_flt),
--
2.35.3