How do you display the IPv6 NDISC cache in Linux?
I think the ip tool just doesn't print the NTF_PROXY flag. In ip/ipneigh.c, after the NTF_ROUTER block, try adding
if (r->ndm_flags & NTF_PROXY) {
fprintf(fp, " proxy");
}
I don't have an NDP proxy installation, so I can't test it. From reading the kernel sources, however, it appears that the entries will all get returned and the flag should be set for proxy entries.