In order to receive the neighbor solicitation messages on the backup slave,
we should add the NS target's corresponding MAC address. But the target in
bonding is a unicast addresses. We can't use it directly. Instead, we should
convert it to a Solicited-Node Multicast Address first and then convert
the multicast address to the right MAC address.

Fixes: 8eb36164d1a6 ("bonding: add ns target multicast address to slave device")
Signed-off-by: Hangbin Liu <liuhangbin@gmail.com>
---
 drivers/net/bonding/bond_options.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/net/bonding/bond_options.c b/drivers/net/bonding/bond_options.c
index 327b6ecdc77e..63cf209dcdc9 100644
--- a/drivers/net/bonding/bond_options.c
+++ b/drivers/net/bonding/bond_options.c
@@ -1246,6 +1246,7 @@ static void slave_set_ns_maddrs(struct bonding *bond, struct slave *slave, bool
 {
 	struct in6_addr *targets = bond->params.ns_targets;
 	char slot_maddr[MAX_ADDR_LEN];
+	struct in6_addr mcaddr;
 	int i;
 
 	if (!slave_can_set_ns_maddr(bond, slave))
@@ -1255,7 +1256,8 @@ static void slave_set_ns_maddrs(struct bonding *bond, struct slave *slave, bool
 		if (ipv6_addr_any(&targets[i]))
 			break;
 
-		if (!ndisc_mc_map(&targets[i], slot_maddr, slave->dev, 0)) {
+		addrconf_addr_solict_mult(&targets[i], &mcaddr);
+		if (!ndisc_mc_map(&mcaddr, slot_maddr, slave->dev, 0)) {
 			if (add)
 				dev_mc_add(slave->dev, slot_maddr);
 			else
-- 
2.39.5 (Apple Git-154)

Oh, I just found the subject is incorrect. We want to receive the NS
message, not NA message on backup slaves.

Thanks
Hangbin
On Wed, Feb 05, 2025 at 08:03:35AM +0000, Hangbin Liu wrote:
> In order to receive the neighbor solicitation messages on the backup slave,
> we should add the NS target's corresponding MAC address. But the target in
> bonding is a unicast addresses. We can't use it directly. Instead, we should
> convert it to a Solicited-Node Multicast Address first and then convert
> the multicast address to the right MAC address.
> 
> Fixes: 8eb36164d1a6 ("bonding: add ns target multicast address to slave device")
> Signed-off-by: Hangbin Liu <liuhangbin@gmail.com>
> ---
>  drivers/net/bonding/bond_options.c | 4 +++-
>  1 file changed, 3 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/net/bonding/bond_options.c b/drivers/net/bonding/bond_options.c
> index 327b6ecdc77e..63cf209dcdc9 100644
> --- a/drivers/net/bonding/bond_options.c
> +++ b/drivers/net/bonding/bond_options.c
> @@ -1246,6 +1246,7 @@ static void slave_set_ns_maddrs(struct bonding *bond, struct slave *slave, bool
>  {
>  	struct in6_addr *targets = bond->params.ns_targets;
>  	char slot_maddr[MAX_ADDR_LEN];
> +	struct in6_addr mcaddr;
>  	int i;
>  
>  	if (!slave_can_set_ns_maddr(bond, slave))
> @@ -1255,7 +1256,8 @@ static void slave_set_ns_maddrs(struct bonding *bond, struct slave *slave, bool
>  		if (ipv6_addr_any(&targets[i]))
>  			break;
>  
> -		if (!ndisc_mc_map(&targets[i], slot_maddr, slave->dev, 0)) {
> +		addrconf_addr_solict_mult(&targets[i], &mcaddr);
> +		if (!ndisc_mc_map(&mcaddr, slot_maddr, slave->dev, 0)) {
>  			if (add)
>  				dev_mc_add(slave->dev, slot_maddr);
>  			else
> -- 
> 2.39.5 (Apple Git-154)
>