For openSUSE Tumbleweed run the following as root:
zypper addrepo https://download.opensuse.org/repositories/security:netfilter/openSUSE_Tumbleweed/security:netfilter.repo
zypper refresh
zypper install shorewall
For openSUSE Factory PowerPC run the following as root:
zypper addrepo https://download.opensuse.org/repositories/security:netfilter/openSUSE_Factory_PowerPC/security:netfilter.repo
zypper refresh
zypper install shorewall
For openSUSE Factory ARM run the following as root:
zypper addrepo https://download.opensuse.org/repositories/security:netfilter/openSUSE_Factory_ARM/security:netfilter.repo
zypper refresh
zypper install shorewall