diff options
| -rw-r--r-- | proto/babel/packets.c | 34 |
1 files changed, 33 insertions, 1 deletions
diff --git a/proto/babel/packets.c b/proto/babel/packets.c index b52c2ddf..72ac4f29 100644 --- a/proto/babel/packets.c +++ b/proto/babel/packets.c @@ -133,6 +133,8 @@ struct babel_write_state { u8 router_id_seen; ip_addr next_hop_ip4; ip_addr next_hop_ip6; + u8 def_ip6_prefix[16]; /* Implicit IPv6 prefix in network order */ + u8 def_ip6_pxlen; }; @@ -150,6 +152,14 @@ struct babel_write_state { #define NET_SIZE(n) BYTES(net_pxlen(n)) +static inline uint +bytes_equal(u8 *b1, u8 *b2, uint maxlen) +{ + uint i; + for (i = 0; (i < maxlen) && (*b1 == *b2); i++, b1++, b2++) + ; + return i; +} static inline u16 get_time16(const void *p) @@ -696,7 +706,29 @@ babel_write_update(struct babel_tlv *hdr, union babel_msg *m, { tlv->ae = BABEL_AE_IP6; tlv->plen = net6_pxlen(&msg->net); - put_ip6_px(tlv->addr, &msg->net); + + /* Address compression - omit initial matching bytes */ + u8 buf[16], omit; + put_ip6(buf, net6_prefix(&msg->net)); + omit = bytes_equal(buf, state->def_ip6_prefix, + MIN(tlv->plen, state->def_ip6_pxlen) / 8); + + if (omit > 0) + { + memcpy(tlv->addr, buf + omit, NET_SIZE(&msg->net) - omit); + + tlv->omitted = omit; + tlv->length -= omit; + len -= omit; + } + else + { + put_ip6_px(tlv->addr, &msg->net); + tlv->flags |= BABEL_FLAG_DEF_PREFIX; + + put_ip6(state->def_ip6_prefix, net6_prefix(&msg->net)); + state->def_ip6_pxlen = tlv->plen; + } } put_time16(&tlv->interval, msg->interval); |