Re: [PATCH v5 05/13] netlink: Return prefix length for IPv6 addresses in nl_addr_get()

On Sun, Feb 22, 2026 at 12:44:37PM -0500, Jon Maloy wrote:

nl_addr_get() was not setting the prefix_len output parameter for IPv6 addresses, only for IPv4. This meant callers always got 0 for IPv6, forcing them to use a hardcoded default (64).

Fix by assigning *prefix_len in the IPv6 case, matching the IPv4 behavior.

Signed-off-by: Jon Maloy

Reviewed-by: David Gibson Moving this patch before 1/13 would address my comment there about the never exercised check on the prefix_len from nl_addr_get().

--- conf.c | 2 +- netlink.c | 4 ++-- 2 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/conf.c b/conf.c index f2ff8af..eb967c7 100644 --- a/conf.c +++ b/conf.c @@ -814,7 +814,7 @@ static unsigned int conf_ip6(struct ctx *c, unsigned int ifi) if (!e) { e = &c->addrs[c->addr_count++]; e->addr = addr; - e->prefix_len = prefix_len ? prefix_len : 64; + e->prefix_len = prefix_len; e->flags = CONF_ADDR_HOST; }

diff --git a/netlink.c b/netlink.c index 82a2f0c..769cb23 100644 --- a/netlink.c +++ b/netlink.c @@ -752,7 +752,7 @@ int nl_addr_set_ll_nodad(int s, unsigned int ifi) * @ifi: Interface index in outer network namespace * @af: Address family * @addr: Global address to fill - * @prefix_len: Mask or prefix length, to fill (for IPv4) + * @prefix_len: Mask or prefix length, to fill * @addr_l: Link-scoped address to fill (for IPv6) * * Return: 0 on success, negative error code on failure @@ -797,7 +797,7 @@ int nl_addr_get(int s, unsigned int ifi, sa_family_t af, ifa->ifa_prefixlen > prefix_max) { memcpy(addr, RTA_DATA(rta), RTA_PAYLOAD(rta));

- prefix_max = ifa->ifa_prefixlen; + prefix_max = *prefix_len = ifa->ifa_prefixlen; }

if (addr_l && -- 2.52.0

-- David Gibson (he or they) | I'll have my music baroque, and my code david AT gibson.dropbear.id.au | minimalist, thank you, not the other way | around. http://www.ozlabs.org/~dgibson