+
+void send_ipv6_ra(sessionidt s, tunnelidt t, struct in6_addr *ip)
+{
+ struct nd_opt_prefix_info *pinfo;
+ struct ipv6_pseudo_hdr *phdr;
+ uint8_t b[MAXETHER + 20];
+ uint8_t c[MAXETHER + 20];
+ int l;
+ uint8_t *o;
+
+ LOG(3, s, t, "Sending IPv6 RA\n");
+
+ memset(b, 0, sizeof(b));
+ o = makeppp(b, sizeof(b), 0, 0, s, t, PPPIPV6, 0, 0, 0);
+
+ if (!o)
+ {
+ LOG(3, s, t, "failed to send IPv6 RA\n");
+ return;
+ }
+
+ *o = 0x60; // IPv6
+ *(o+1) = 0;
+ *(o+5) = 48; // Length of payload (not header)
+ *(o+6) = 58; // icmp6 is next
+ *(o+7) = 255; // Hop limit
+ memset(o+8, 0, 16); // source = FE80::1
+ *(o+8) = 0xFE;
+ *(o+9) = 0x80;
+ *(o+23) = 1;
+ if (ip != NULL)
+ {
+ memcpy(o+24, ip, 16); // dest = ip
+ }
+ else
+ {
+ // FF02::1 - all hosts
+ *(o+24) = 0xFF;
+ *(o+25) = 2;
+ *(o+39) = 1;
+ }
+ *(o+40) = 134; // RA message
+ *(o+41) = 0; // Code
+ *(o+42) = *(o+43) = 0; // Checksum
+ *(o+44) = 64; // Hop count
+ *(o+45) = 0; // Flags
+ *(o+46) = *(o+47) = 255; // Lifetime
+ *(uint32_t *)(o+48) = 0; // Reachable time
+ *(uint32_t *)(o+52) = 0; // Retrans timer
+ pinfo = (struct nd_opt_prefix_info *)(o+56);
+ pinfo->nd_opt_pi_type = ND_OPT_PREFIX_INFORMATION;
+ pinfo->nd_opt_pi_len = 4;
+ pinfo->nd_opt_pi_prefix_len = 64; // prefix length
+ pinfo->nd_opt_pi_flags_reserved = ND_OPT_PI_FLAG_ONLINK;
+ pinfo->nd_opt_pi_flags_reserved |= ND_OPT_PI_FLAG_AUTO;
+ pinfo->nd_opt_pi_valid_time = htonl(2592000);
+ pinfo->nd_opt_pi_preferred_time = htonl(604800);
+ pinfo->nd_opt_pi_reserved2 = 0;
+ pinfo->nd_opt_pi_prefix = config->ipv6_prefix;
+ l = sizeof(*pinfo) + 56;
+
+ memset(c, 0, sizeof(c));
+ phdr = (struct ipv6_pseudo_hdr *) c;
+ memcpy(&phdr->src, o+8, 16);
+ memcpy(&phdr->dest, o+24, 16);
+ phdr->ulp_length = htonl(l - 40);
+ phdr->nexthdr = IPPROTO_ICMPV6;
+
+ memcpy(c + sizeof(*phdr), o + 40, l - 40);
+
+ // Checksum is over the icmp6 payload plus the pseudo header
+ *(uint16_t *)(o+42) = _checksum(c, l - 40 + sizeof(*phdr));
+
+ tunnelsend(b, l + (o-b), t); // send it...
+ return;
+}