Re: [RFC 01/12] ip: Introduce multi-address data structures for IPv4 and IPv6

On Sun, Dec 14, 2025 at 08:54:30PM -0500, Jon Maloy wrote:

As preparation for supporting multiple addresses per interface, we replace the single addr/prefix_len fields with arrays.

- We add an ip4_addr_entry and an ip6_addr_entry struct containing address and prefix length.

- We set the array sizes to IP4_MAX_ADDRS=8 and IP6_MAX_ADDRS=16, respectively.

The only functional change is that the IPv6 prefix length now is properly stored instead of being hardcoded to 64 even when set via the -a option.

Signed-off-by: Jon Maloy --- arp.c | 4 +-- conf.c | 97 +++++++++++++++++++++++++++++++++----------------------- dhcp.c | 8 ++--- dhcpv6.c | 6 ++-- fwd.c | 12 +++---- ip.h | 26 +++++++++++++++ ndp.c | 6 ++-- passt.h | 16 ++++++---- pasta.c | 12 ++++--- tap.c | 4 +-- util.h | 1 + 11 files changed, 122 insertions(+), 70 deletions(-)

diff --git a/arp.c b/arp.c index bb042e9..7eaf517 100644 --- a/arp.c +++ b/arp.c @@ -54,7 +54,7 @@ static bool ignore_arp(const struct ctx *c, return true;

/* Don't resolve the guest's assigned address, either. */ - if (!memcmp(am->tip, &c->ip4.addr, sizeof(am->tip))) + if (!memcmp(am->tip, &c->ip4.addrs[0].addr, sizeof(am->tip))) return true;

Sorry, missed this on my first pass. This needs to skip *all* of the guest addresses, not just the first one. Otherwise passt will respond to arps for the guest's other addresses with its own MAC which will break everything. -- 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