[patch libteam] teamd: lw: arp_ping: bitmask VID in VLAN BPF filter

[Robert Karbowski]

(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 
---
 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),

[Jiri Pirko]

Sun, May 19, 2024 at 11:56:38PM CEST, [e-mail] wrote:
> (2nd attempt to publish patch since update via “git send-mail” seems to be lost)

I see the first, ignoring this one.