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770bce967c
In the most common case, an IPv6 address doesn't have a peer and the IFA_ADDRESS netlink attribute contains the address itself. But if the address has a peer (typically for point to point links), then IFA_ADDRESS contains the peer address and IFA_LOCAL contains the address [1]. [1] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/net/ipv6/addrconf.c?h=v5.17#n5030 Fix the parsing of IPv6 addresses with peers, as currently dnsmasq unsuccessfully tries to bind on the peer address. A simple reproducer is: dnsmasq --conf-file=/dev/null -i dummy1 -d --bind-dynamic & sleep 2 ip link add dummy1 type dummy ip link set dummy1 up ip addr add dev dummy1 fd01::1/64 peer fd01::2/64 ip addr add dev dummy1 fd01::42/64 sleep 2 ss -lnp | grep dnsmasq | grep fd01 Before the patch: dnsmasq: failed to create listening socket for fd01::2: Cannot assign requested address dnsmasq: failed to create listening socket for fd01::2: Cannot assign requested address udp UNCONN 0 [fd01::42]:53 [::]:* users:(("dnsmasq",pid=23947,fd=14)) tcp LISTEN 0 [fd01::42]:53 [::]:* users:(("dnsmasq",pid=23947,fd=15 After: udp UNCONN 0 [fd01::42]:53 [::]:* users:(("dnsmasq",pid=23973,fd=16)) udp UNCONN 0 [fd01::1]:53 [::]:* users:(("dnsmasq",pid=23973,fd=14)) tcp LISTEN 0 [fd01::42]:53 [::]:* users:(("dnsmasq",pid=23973,fd=17)) tcp LISTEN 0 [fd01::1]:53 [::]:* users:(("dnsmasq",pid=23973,fd=15))