Applied RFC 4862; separation into 128-N and N bits (for N=14)

diff --git a/6bed4peer.c b/6bed4peer.c
index 47ff2d6..b01833c 100644 (file)
--- a/6bed4peer.c
+++ b/6bed4peer.c
@@ -54,6 +54,7 @@
 
 
 #define MTU 1280
+#define PREFIX_SIZE 114
 
 typedef enum {
        METRIC_LOW,
@@ -335,7 +336,7 @@ syslog (LOG_CRIT, "Bad news!\n");
        if (ok && system (cmd) != 0) {
                ok = false;
        }
-       snprintf (cmd, 512, "/sbin/ip -6 addr add %s/64 dev %s", v6prefix, ifreq.ifr_name);
+       snprintf (cmd, 512, "/sbin/ip -6 addr add %s/114 dev %s", v6prefix, ifreq.ifr_name);
        if (ok && system (cmd) != 0) {
                ok = false;
        }
@@ -885,7 +886,7 @@ void handle_4to6_nd (struct sockaddr_in *sin, ssize_t v4ngbcmdlen) {
                                return;   /* out of packet length */
                        } else if (v4v6icmpdata [rdofs + 3] & 0xc0 != 0xc0) {
                                /* no on-link autoconfig prefix */
-                       } else if (v4v6icmpdata [rdofs + 2] != 114) {
+                       } else if (v4v6icmpdata [rdofs + 2] != PREFIX_SIZE) {
                                /* not a /114 prefix, so no 6bed4 offer */
                                return;
                        } else {
@@ -897,11 +898,27 @@ void handle_4to6_nd (struct sockaddr_in *sin, ssize_t v4ngbcmdlen) {
                        memcpy (v6listen.s6_addr + 0, destprefix, 16);
                        v6listen.s6_addr [14] &= 0xc0;
                        v6listen.s6_addr [15]  = 0x01;  // choose client 1
-                       memcpy (v6listen_linklocal_complete+0,
-                                       v6listen_linklocal, 8);
-                       memcpy (v6listen_linklocal_complete+8,
-                                       v6listen.s6_addr+8, 8);
-                       memcpy (v6lladdr, v6listen_linklocal_complete+8, 8);
+                       int prefixBits = PREFIX_SIZE;
+                       int i;
+                       for (i = 0; prefixBits >= 8; i++) {
+                               v6listen_linklocal_complete [i] = v6listen_linklocal [i];
+                               prefixBits -= 8;
+                       }
+                       if (prefixBits > 0) {
+                               int mask = (1 << (8 - prefixBits)) - 1;
+                               v6listen_linklocal_complete [i] = v6lladdr [i] = (v6listen_linklocal [i] & ~mask) | (v6listen.s6_addr [i] & mask);
+                               i++;
+                       }
+                       while (i < 16) {
+                               v6listen_linklocal_complete [i] = v6lladdr [i] = v6listen.s6_addr [i];
+                               i++;
+                       }
+
+//                     memcpy (v6listen_linklocal_complete+0,
+//                                     v6listen_linklocal, 8);
+//                     memcpy (v6listen_linklocal_complete+8,
+//                                     v6listen.s6_addr+8, 8);
+//                     memcpy (v6lladdr, v6listen_linklocal_complete+8, 8);
                        //TODO// Is v6lladdr useful?  Should it include lanip?
                        v6lladdr [0] &= 0xfc;
                        v6lladdr [0] |= (v6listen_linklocal_complete [14] >> 6);