dhcpv6: use a per-interface IAID for IA_NA requests

This ensures that the same IAID isn't used when odhcpd is e.g. running
on different interfaces (RFC8415, §12). This is more important now that
global DUID support has landed [1], meaning that odhcp6c won't typically
use per-interface DUIDs.

[1] https://github.com/openwrt/openwrt/pull/20359

Signed-off-by: David Härdeman <[email protected]>
Link: https://github.com/openwrt/odhcp6c/pull/105
Signed-off-by: Álvaro Fernández Rojas <[email protected]>

diff --git a/src/dhcpv6.c b/src/dhcpv6.c
index fa0c2a1787ca91b7b0b686767b4b37b5a89176a8..2075006b6cc61de772648df563d14284eb590ea5 100644 (file)
--- a/src/dhcpv6.c
+++ b/src/dhcpv6.c
@@ -479,9 +479,11 @@ static void dhcpv6_send(enum dhcpv6_msg type, uint8_t trid[3], uint32_t ecs)
        ia_na_entries /= sizeof(*e);
 
        struct dhcpv6_ia_hdr hdr_ia_na = {
-               htons(DHCPV6_OPT_IA_NA),
-               htons(sizeof(hdr_ia_na) - 4),
-               htonl(1), 0, 0
+               .type = htons(DHCPV6_OPT_IA_NA),
+               .len = htons(sizeof(hdr_ia_na) - 4),
+               .iaid = htonl(ifindex),
+               .t1 = 0,
+               .t2 = 0,
        };
 
        struct dhcpv6_ia_addr pa[ia_na_entries];
@@ -1156,7 +1158,7 @@ static int dhcpv6_handle_reply(enum dhcpv6_msg orig, _unused const int rc,
                                        continue;
 
                                // Test ID
-                               if (ia_hdr->iaid != htonl(1) && otype == DHCPV6_OPT_IA_NA)
+                               if (ia_hdr->iaid != htonl(ifindex) && otype == DHCPV6_OPT_IA_NA)
                                        continue;
 
                                uint16_t code = DHCPV6_Success;